Firsts of Their Kinds:Products
Trial Production of the World's First Double-Coil Bulb
A world-class invention rivaling Edison's carbon bulb, Coolidge's drawn-wire tungsten bulb, and Langmuir's gas-filled bulb
Hakunetsu-sha (one of Toshiba's predecessors) was established in 1890 and started production of incandescent bulbs. However, making carbon filaments was extremely difficult back then. To create the bulb filament, the company first used cotton that had come with an English bulbmanufacturing machine the company had purchased from England, and then later followed Thomas Edison's example and tried bamboo. Since both materials had a high burnout rate, the company employed carbon filament made from cotton in 1900.
Having learned about the production of tungsten bulbs in the U.S. and Europe, Hakunetsu-sha began small-scale production of a prototype at its Mita main factory around 1907. The company later built a tungsten bulb production line and started full-scale production in 1910 at its newly constructed Kawasaki factory.
However, tungsten bulbs at the time used low-quality extruded-tungsten filament and productivity was low. The price of bulbs using this type of filament became quite high, and for a time the business was not profitable.
The news of William Coolidge's invention of drawn-wire tungsten filaments at the GE laboratories reached Japan in 1911. Hakunetsu-sha started production and sales of bulbs containing drawn-wire tungsten filament in October of the same year.
The invention of the ductile tungsten filament led to a fundamental improvement in material strength and uniform quality. It also had a revolutionary influence over the manufacturing of bulbs supported by the development of gas evacuation equipment for bulbs.
Irving Langmuir later discovered that the life of a bulb depended on the evaporation of tungsten from the filament. Thinking that the life of the filament could be extended by slowing the evaporation, in 1913 he invented a tungsten bulb filled with nitrogen gas, which is a substance that does not chemically combine with tungsten. Hearing the news, Hakunetsu-sha immediately imported and sold these bulbs in Japan and started making its own prototype.
A number of discoveries were made. Gas-filled bulbs were not so susceptible to blackening because less tungsten evaporated from the filament. A layer of gas is formed around the surface of the filament in an inert-gas environment–such as one using nitrogen–and a filament with a larger diameter loses less gas. Based on these facts, the effective diameter was made larger by converting a straight wire into a coil, and the assembly became known as a coiled-tungsten filament.
Engineers at Hakunetsu-sha conducted a great deal of research on the coiled-tungsten filament, particularly an engineer named Junichi Miura. Miura made the first prototype of the double-coil bulb in 1921. The double-coil bulb was more efficient than the single-coil bulb and people's expectations for the product were high. However, technology to mass-produce these bulbs was not yet available, and they were not put into practical use.
Hakunetsu-sha continued its research into tungsten filaments, gas-filled bulbs, and experimental double-coil bulbs. In 1930, the company adopted the product as a special bulb for kinetoscopes. It later created a technique to mass-produce double-coil bulbs that had the same level of uniformity as conventional gas-filled bulbs. They were launched as the new Mazda lamp–a gas-filled double-coil bulb–in 1936.
World's First Frosted Light Bulbs
An invention of global importance, on a par with the drawn-wire tungsten bulb developed by Dr. Coolidge and the gas-filled bulb developed by Dr. Langmuir.
Thomas Edison invented the incandescent lamp in 1879, incorporating a filament prepared by carbonating cotton fiber. Subsequently, in order to make long-lasting filaments, he gathered thousands of different materials from around the world and found that madake bamboo from Iwashimizu- Hachimangu in Kyoto was the best. He then developed practical carbon-filament light bulbs using madake bamboo for the filaments. This marked a turning point for the rapid development of electric lighting in Western countries.
In Japan, Tokyo Electric Light Company (the predecessor of Tokyo Electric Power Company) was established in 1883, and Dr. Ichisuke Fujioka, a professor at The Imperial College of Engineering (the predecessor of the Faculty of Engineering of The University of Tokyo), was invited to join the company as chief engineer. By 1888, several thermal power plants had been completed in succession and the number of electric lighting users finally began to increase. The reality was, however, that the key components—the light bulbs themselves—were all foreign products.
Fujioka therefore established a company called Hakunetsusha (one of Toshiba’s predecessors) in 1890 for the domestic production of light bulbs. The filaments were initially made using cotton thread, but it was found that incandescent bulbs suitable for practical use could not be produced by this method. Hearing that Japanese madake bamboo had been adopted as a filament material in the U.S., Hakunetsu-sha immediately started using it and, as a result, succeeded in manufacturing light bulbs for the first time in 1890. Although the production volume reached the level of 3,000 bulbs per month by 1892, they were not competitive in terms of price and foreign products continued to hold the largest market share. Several years later, in 1900, the company succeeded in manufacturing carbon filaments made from cotton and the volume of production rapidly increased.
In 1911, Dr. William Coolidge’s invention of drawn-wire tungsten filaments at General Electric Company (GE) in the U.S. was reported, and Hakunetsu-sha also started production and sales of bulbs incorporating drawn-wire tungsten filament. The development of this drawn-wire tungsten filament led to a fundamental improvement in material strength and uniformity of quality, and had a major impact on bulb manufacturing supported by the development of gas evacuation equipment for bulbs. Dr. Irving Langmuir of GE subsequently discovered that the life of a bulb depended on the evaporation of tungsten from the filament. Based on the hypothesis that the life of the filament could be extended by slowing this evaporation, in 1913 he invented a tungsten bulb filled with nitrogen gas, which does not chemically combine with tungsten. Upon hearing the news of this invention, Hakunetsu-sha immediately began to import and sell these bulbs in Japan and started making its own prototype. In 1915, it succeeded in manufacturing light bulbs filled with nitrogen gas.
With the appearance of gas-filled tungsten bulbs, the efficiency of bulbs was enhanced and both their luminous intensity and surface brightness became increasingly high. As a result, glare became a major problem in the field of general lighting. The first countermeasure taken to deal with this problem was frosting of the exterior surface of the bulbs. A drawback of this method, however, was that the surface became easily soiled and cleaning was difficult, leading to a rapid decrease in the amount of light transmitted. One of the company’s engineers, Kyozo Fuwa, then had the idea of frosting the interior surface of the bulbs and conducted research into this method. Unfortunately, glass bulbs with a chemically frosted interior surface turned out to be very fragile and unsuitable for practical use. After further strenuous research efforts, in 1925 he finally succeeded in manufacturing light bulbs with a frosted interior surface that were equivalent in strength to bulbs with exterior frosting.
World's Largest Hydropower Generating Units Installed on the Yalu River
Contract awarded for water turbines and generators for the Supung Power Station in 1938 amid rising political tensions at home and abroad
In the early Showa Period (1930s), a project was proposed to develop hydropower sources on the Pujon, Heochun, and Changjin rivers in the northern part of the Korean Peninsula to exploit the abundant hydropower potential in that area. The aim of the project was to supply electric power for the mass-production of chemical fertilizers, and the Korea Nitrogenous Fertilizer Company was established for this purpose. The hydropower development was managed by Korea Hydroelectric Power Company (KHPC) and Changjin Hydroelectric Power Company (CHPC).
At the beginning, Shibaura Engineering Works and Dengyosha Prime Mover Works (both of which were Toshiba's predecessors) received an order from KHPC for two vertical-shaft Francis turbine units for the Pujon River No. 2 Power Station. Thereafter, they received orders for a total of 35 units of turbines and generators for 11 power stations (all except for one power station in the whole project) from both hydroelectric power companies.
Most of these machines were unprecedented in those days in terms of operating head and unit capacity, so many U.S. and European manufacturers were competing with Shibaura and Dengyosha. However, they overcame the tough competition and successfully won the contracts, reflecting the customers' reliance on the companies and their technologies.
After the successful completion of the project, another major project was proposed to develop a large hydropower station called the Supung Power Station on the Yalu River on the border between Manchuria and Korea. Owing to their good performance in the previous project, Shibaura and Dengyosha successfully won the contract for all seven turbines rated at 105 MW each and five generators rated at 100 MVA each in March 1938 from Yalu River Hydropower Company, the developer of the project. At that time they were the world's largest units in terms of unit capacity.
The 105 MW turbines were vertical-shaft Francis turbines operating with an 82-meter head. Three of them were designed to be operated at both 50 and 60 Hz, while two were designed for 50 Hz and the other two for 60 Hz. They surpassed by far the 85 MW turbines at the Boulder Dam in the U.S., which were the largest turbines before that time. Political tension was already on the rise around Japan at the time of the contract. Therefore, upon receipt of the order, Shibaura and Dengyosha took immediate action for the production of these large-scale machines such as design work, procurement of materials, and so forth. In particular, they requested various material manufacturers for their cooperation to ensure smooth supplies of the large amounts of materials required to build these machines.
In September 1938, the embedded parts of the first turbine were shipped to the site and the main part of the turbine was completed in the shop early in the autumn of 1939. According to the documents detailing the shipments, these recordbreaking super-size turbines were shipped thereafter at an average interval of 4.5 months. This was an amazingly short interval for wartime, when labor and materials were scarce. Shibaura and Dengyosha built a new factory with a large pit for shop assembly of the huge generators and to perform rotation tests before shipment. The rotation test of the first 50/60 Hz generator was conducted in June 1940, verifying its performance and operational reliability.
The first unit was commissioned in September 1941 and a commemoration ceremony was held at the site. We can feel the sense of pride in those who accomplished this great task through a framed inscription written by former senior managing director Jugoro Otaguro, who was the founder of the turbine manufacturing business in Dengyosha. The inscription says, “In the early days, half a horsepower. Today, 143,000 horsepower, the highest in the world.”
The completion of these largest generators in the world owes much to the dedicated efforts of the engineers involved. They succeeded in achieving many technological breakthroughs toward larger unit capacity, higher voltage, larger machine design, and improvement of the bearings and the generator's construction as a whole.
World's First Helical Scan Video Tape Recorder
Toshiba made a major contribution to the growth of Japan's economy in the 1980's with its helical scan videotape recorder which are in use around the world by hundreds of millions.
When black-and-white television broadcasting in Japan began in 1953, there was a need for devices that could electronically record and playback the video signals of nonlive broadcasts. At that time, programs were recorded on movie film and played back by converting the film images to electric signals. Although the open-reel magnetic tape recording method was on the market for recording audio signals, since recording video signals required as much as 100 times the bandwidth used for recording audio signals, tape speed would need to be increased to 19 meters/second. However, since recording and playing back video images on movie film required long processing times and high costs, expectations were high for using a magnetic recording method.
RCA in the U.S. and BBC Laboratories in the U.K. had responded by increasing tape speeds to several meters/ second, but it was the American star Bing Crosby who funded, with his own money, development of a recording device that split video signals into ten simultaneous tracks. This experiment showed that if the relative speed of the tape and the magnetic heads could be increased by doubledigit amounts, video signals could be recorded on magnetic tape. This led to the idea of the rotating head. In 1956, a U.S. firm called Ampex succeeded in developing a practical device based on the recording method it had invented: using four rotating heads placed at 90-degree intervals across the width of a two-inch wide tape to record and playback one-fourth of the signal using each of the four heads.
But since this method combined the signal segments from these four heads into a single video image, it had drawbacks in that some color distortion arose from the characteristics of the individual heads, and joints were visible between signal segments. For this reason, in 1954 Toshiba began research into a recording method using diagonal heads. By forming a single diagonal, long track on two-inch-wide tape, it was possible to record a video signal on one tape using one head, with no joints. This helical scan method was invented by Dr. Kenichi Sawazaki of the Mazda Research Laboratory.
However, it is extremely difficult to run a device with stability when the head is constantly in contact with the tape, and only after much testing was an experimental prototype (Toshiba's first videotape recorder) announced, in 1959. This attracted attention from around the world, and made a major impact when announced at a meeting of the Society of Motion Picture Television Engineers (SMPTE) held at the Ambassador Hotel in Los Angeles. Broadcasting use videotape recorders needed to be compatible, however, the technology adopted as standard was Ampex's four-head method. But, as far as industrial videotape recorders were concerned, since the manufacturing cost using Toshiba's helical scan method was one-tenth or less that of the fourtrack method, Toshiba's helical scan method was adopted. The all-in-one open-reel videotape recorder was standardized in 1969 and introduced to the market for general use. Subsequently, this method was also used for home video recorders using the cassette β(beta) and VHS formats. Today, hundreds of millions of videotape recorders are in use around the world, and even broadcasting-use recorders use the helical scan method. The helical scan videotape recorder has earned high credit as a technology in use around the world, and it made a major contribution to the growth of Japan's economy in the 1980's.
World's First Large-Capacity Static Uninterruptible Power Supply (UPS)
Large-capacity power supply was made possible by the development of a power semiconductor device called a thyristor.
Toshiba laid the foundation for the development of the uninterruptible power supply (UPS) systems that support today's highly sophisticated information-based society.
In the past, rotating motor generators (MG sets) were used to provide a stable power supply for communication equipment and information processing systems, including computers. In 1964, Toshiba commercialized its first static UPS (5 kVA capacity), making use of a power semiconductor device called a thyristor. Three years later, in 1967, the company released a large-capacity UPS (200 kVA). This equipment was utilized in the air traffic control system at Haneda International Airport in Tokyo, where even a onesecond power outage could result in disaster.
Basically, a UPS receives commercial AC power and converts it into DC power through a silicon rectifier. The power is further converted into stable AC power by a thyristor inverter and supplied to the load system. At the same time, a battery is charged in order to supply DC power to the thyristor inverter, so that the inverter can continue to supply AC power to the load in the event of commercial power failure. In addition to making use of commercial power, a UPS is equipped with an emergency in-system power generator. The generator produces AC power in order to supply system operations in place of the commercial power supply, before the battery runs out of power.
At the time, the device was referred to as a constant voltage and constant frequency (CVCF) unit because it provided stable voltage and frequency. Today, it is called an uninterruptible power supply, or UPS for short, in order to emphasize its ability to supply power uninterruptedly. Japan was moving rapidly toward the computer era at the time the UPS was developed, and computers were becoming faster, increasingly sophisticated, and more widespread. Under these circumstances, stable and highly reliable UPS systems became essential for the protection of computers from power failure. In the 1970s, a number of technologies were developed that further enhanced the reliability of UPS systems. These technologies allowed for practical application of an uninterruptible switching device to supply power to the load uninterruptedly as a bypass power supply. It also allowed for the development of a high-speed thyristor interrupter that used a parallel redundancy system made up of several UPS units, and made possible the development of high-performance, highly reliable system control technologies. As a result, Toshiba was able to launch the TOSNIC (Toshiba noninterruptible converter) series, available in capacities from 50 to 300 kVA.
To convert DC power into AC power, the converter used a McMurray inverter incorporating a 600 V-300 A highspeed thyristor, a commutating reactor, and a commutating capacitor. Later, after a self-arc-suppression type power semiconductor device was developed, gate turn-off thyristor (GTO)-based inverters and converters were put to use, followed by insulated gate bipolar transistor (IGBT)-based inverters and converters. Thanks to the development of power semiconductor devices, UPS systems realized high efficiency, high functionality, and high reliability and have responded well to the needs of society. In the late 1980s, an online computer center equipped with a 13,000 kVA UPS was established. Today, UPS systems have become indispensable in supplying uninterrupted power for important systems at data centers, control centers, and semiconductor manufacturing sites.
World's First Mail Processing Equipment
Labor mechanized by the world's first automatic postal code reading and sorting device that could recognize handwritten characters, which led to development of labor-saving machines for an advanced information society which was soon to come.
Japan's postal system began in 1871. However, for about 100 years until Toshiba developed the world's first automatic postal code reading and sorting device that could recognize handwritten characters in 1967, mail was sorted by hand. For this reason, the efficiency of sorting operations depended on the level of expertise of the persons doing the sorting.
Adoption of machinery to improve the efficiency of postal operations was under consideration. In 1965, a project began under the leadership of the Ministry of Posts and Telecommunications. This project consisted of the Devices Division (at the time, the Yanagimachi Plant) and the General Research Laboratory (now the Research & Development Center), and was initiated with an analysis of the systems used inside a post office. What then followed was the development of machines with specific functions; firstly, an automatic mail reading and recognition device (TR), then an automatic mail handling and printing device (TC), and finally an automatic mail sorting device (TS).
In 1966, the first trial device was completed for reading non-cursive handwritten numerals. Next, the project was entrusted with research into reading freely written numerals, which involved a wide range of handwritten characters collected from around the country. This analysis resulted in a report that reading such numbers was feasible. In 1967, the General Research Laboratory's optical character recognition (OCR) technology was used to complete, at long last, the world's first device for reading handwritten characters, the TR-2.
This recognition device was composed of three types of components: the mechanical components that handled the letter itself, the recognition components that read and recognized the postal code, and the control components that determined the category for the letter based on the postal code written thereon. Letters placed in the feeder were sent through one at a time, and only the postal code was converted to an electrical signal, using a visicon (digital) camera. This signal was sent to the recognition section as a numerical signal via a circuit which detects and queries only the postal codes, where recognition was made using a unique selection system. The results from here were transmitted to the control components, where, after the appropriate category pocket had been chosen, the letter was transported via synchronized categorization gates into the designated pocket.
The red squares on envelopes used for writing postal codes are unique to Japan. The use of these boxes makes it possible for optical technology to convert the lines of the numerals within these fixed boxes to signals. However, freely written numerals vary widely according to factors such as the writing implement used, the size and location of the characters, and the width and density of the lines used. Repeated improvements were made by gathering samples containing as many as 300,000 characters from across the country and conducting analysis simulation. This resulted in the manufacture of the TR-3 (with 50 category pockets) and TR-4 (with 100 category pockets) models for practical use. Together with the start of the postal code system, these were announced publicly on July 1, 1968 at Tokyo's Central Post Office.
In parallel to practical realization of the mail reading and recognition device (TR), the company completed the world's first automatic mail handling and printing device (TC) through detection of stamps in 1967. In 1968, the company also completed the mail reading and recognition device capable of recognizing letterpress numbers. For all these efforts, Toshiba won the Prize of Japan Society for the Promotion of Machine Industry in 1969 and the Mainichi Industrial Technology Award in 1970 and received high acclaim from home and abroad. The machine led to development of labor-saving machines in post offices, stations and banks for an advanced information society which was soon to come.
World's First Set-Free Room Air Conditioner
Testing started with a cardboard model.
A room at the division director's home flooded with water during practical testing.
Around 100,000 small air conditioners were sold industrywide in 1965. By that time, TVs, refrigerators and washing machines had become ubiquitous, but although air conditioners were expected to become more widespread, they had yet to become popular. After an investigation as to why air conditioners were not adopted as quickly as other home appliances, the development team reached a conclusion that sales would increase if customers could install air conditioners by themselves where they wanted without having to pay for installation, and if they could remove the units when they were not necessary (air conditioners had only cooling functions at that time).
Development started from scratch. The members of the development team started with selection of the condensing heat exchanger, followed by choosing a hose to exhaust heat, a pump to circulate water and conducting a study on the ideal arrangement of components. The air conditioner was designed like a piece of furniture so that the whole unit would fit in aesthetically when it was installed in a room. The members also measured the sizes of doorsills, rails and carpets to make the product easy to move within the home. Members went from shop to shop, after work and on holidays, looking for suitable storage tanks, exhaust hoses, casters, and handles. A cardboard layout model was made to give shape to the designer's vision before building the first prototype.
In the summer of 1966, a practical test of the first prototype was conducted. The product had some flaws, and one room in the division director's home was flooded with water. The prototype had problems: it made a lot of noise, and had a faulty switch (designed to automatically stop the compressor when cooling water ran out). The members had to deal with a number of issues during the test, running around the house while doing so, yet they firmly believed that their air conditioner was worthy of being installed in Japanese homes in the years to come.
The next prototype was made at lower cost and the problems identified in the first test were overcome. The prototype was put through its second round of practical testing in the summer of 1967. A project team was organized to go over any design suggestions from testing. The team focused on finding ways to prevent substances in the water from accumulating in the water tank, surfaces of the copper piping and the water hose in the form of evaporation residue. They also conducted research on water deposit cleaners, and on the ideal construction that would make the air conditioners easier to clean.
On May 7, 1968, Toshiba started mass production of 500 units. Competitors were shocked by the news about this revolutionary air conditioner. Toshiba built 12,000 units in 1969 and more than 80,000 units in 1972. Toshiba was far ahead of other companies in this field for five consecutive years.
The company received the award for technological achievement (the advancement award) from the Japan Electrical Manufacturers' Association for its water-cooled set-free air conditioners in April 1970. In March 1973, Toshiba started mass production of air-cooled set-free air conditioners, which overcame the shortcomings of the previous water-cooled unit, e.g. water supply and deposit accumulation. Toshiba again received the technological achievement award from the Japan Electrical Manufacturers' Association in April 1974 for their new air-cooled version of the set-free air conditioner.
World's First Largely Integrated-circuit Color Television
A color TV incorporating the latest electronic technologies attracted attention by offering infrequent breakdowns, low energy consumption, and stable television images.
The integrated circuit (IC) was invented in 1959 by Texas Instruments' Jack Kilby in the US. The key point in Kilby's patent was the building of electronic components such as transistors, resistors, and condensers inside silicon crystal, so that the crystal itself functioned as a circuit. At the root of this technology was the planar transistor developed by Fairchild Semiconductor of the US. The technological innovations that made this planar (flat) structure possible — silicon-oxide film molding and diffusion processing of impurities — enabled the development of the small, highspeed, highly reliable IC devices essential to today's electronics.
Toshiba was quick to develop the first transistor television set built in Japan, which was completed in 1959. It also took the lead over its competitors in adopting IC technology to color televisions, starting with automatic fine tuning (AFT) circuitry in 1969. This was followed by the development of audio and color signal demodulation circuitry, as Toshiba aggressively worked to apply IC technologies to the television. In 1971, it introduced the world's first largely IC color television, the 20C60, which used 11 IC circuits.
This IC television did not use IC circuits entirely. Rather, it used both IC circuitry and transistors. The IC circuit was used for the tuner, output, power supply, horizontal oscillation, and amplifier, as well as most of the video amplifier components. All ICs used were bipolar semiconductors. Not only did this television use a large amount of IC technology, it also included a Brightron picture tube to ensure that the image on the CRT tube would not fade even under direct light, and a Uni-Auto system that made automatic fine-tuning possible using a single switch. In addition, the newly developed 2SC1172 transistor combined horizontal output and high-voltage generation.
Applying the strong points of IC technology made it possible to develop high-performance television circuitry that was not possible using previous individual components. In addition, it massively reduced the number of circuitry parts used, as well as the number of soldered points, thus improving reliability. The space required for circuitry was reduced, and printed-circuit boards were modularized by function, making it possible to attach them using connectors. Additionally, use of a smaller chassis reduced the cabinet depth by 40 millimeters. This development also made it possible to reduce the labor required in assembly processes by standardizing circuitry between different television models and by reducing the need for manual assembly.
The IC color television, which was completed through incorporation of the latest electronic technologies, achieved in all areas levels of quality inconceivable in the past, with infrequent breakdowns, low energy consumption, and stable television images, among other improvements.
World's First Black-stripe Color Cathode-ray Tube
Clearer and brighter – an innovative product incorporating a world-standard color cathode-ray tube.
In the late 1950's, joint research into trial production of color cathode-ray tubes took place among all television manufacturers, centered on the NHK Science & Technical Research Laboratories. A gradual shift to production took place in the 1960's, with the color television market growing rapidly due to the Tokyo Olympics held in 1964.
At the time, delta electric gun and round shadow masking methods based on U.S. technology were used. However, beginning in the latter half of the 1960s the shift from 70-degree tubes to 90-degree tubes took place. Performance improved massively with adoption of new technologies, such as improved brightness from use of rare-earth phosphors, use of bimetal technology for the heat expansion of shadow masking, and improved clarity from use of blackmatrix (BM) screens. However, there were many areas that needed improvement, and since color and convergence adjustments were complex, so too was the required circuitry, which made it costly. The core of the problem was to increase resolution and shorten the length of the tube, by widening it.
These issues were resolved by developing a color tube with an inline arrangement of three electron guns, together with a newly developed slit-shadow mask combination, and stripe screen. However, although this combination of technologies promised many benefits for color tubes in terms of performance and other factors, manufacture of such tubes was a lot more complex, since new parts and processes had to be developed to realize the new technologies.
Design and process conditions for the slit mask, the feasibility of which itself was unclear, were nevertheless determined through repeated trial and error. This led to the prospect of completion of a slit mask structure that had resolution, hole ratios, and power at levels that could be implemented at the practical level. This slit mask, which had a high hole ratio, achieved brightness levels 20% higher than previous tubes. For the screen, an inline color tube and a BM screen were used. Manufacture of BM screens was complicated by factors related to phase and out-of-sync slit mask holes. These were resolved over time by fluctuation of long light sources and adoption of a new exposure method using a shutter.
Inline color tubes not only achieved higher brightness levels and lower cost, they also made possible accurate landing not just for the upper and lower portions of the screen but horizontally as well, and further, they improved color performance and made adjustments easy. In 1971, a 14-inch screen using a phosphor stripe tube was brought to market, followed by a 110-degree 20-inch BKS tube. A non-BS tube also took the world by storm. This color cathode-ray tube was the origin of the global standard for present day color TV cathode-ray tubes (i.e., inline electron gun, slit mask, and stripe screen).
World's First One-Tube Color Camera for Consumer Use
The world's first helical VTR led to the development of the frequency interleaving camera tube.
The world's first color home video camera was developed by Toshiba in 1973.
Today, home video cameras can easily obtain high-quality color video signals, and are widely used throughout the world. Back in the 1970s, however, engineers at Toshiba struggled to develop a compact camera that could acquire the three primary color signals from only one image pickup tube.
At the time, large and expensive color video cameras were mostly used in television stations, although similar cameras were also used for educational and medical purposes. Those cameras employed a three-tube method, by which three camera tubes created image signals through an expensive optical prism that divided incident rays from an object into the three primary colors: red, green, and blue. The threetube method made it extremely difficult to put color cameras on the home market, because a single camera required three costly camera tubes and complicated adjustment technology to accurately overlap the three color images.
To realize a home-use video camera, it was necessary to make a compact camera using a single tube. The engineers therefore decided to use a frequency multiplexing method. Frequency multiplexing extracts red, green and blue signals by changing the pitch of two different color stripe filters. However, this method requires high-resolution camera tubes which, although they were used in specific applications, were too expensive for home-use color cameras. So the engineers tried various other ideas. A new frequency interleaving method, which placed color filters at an angle diagonal to the line scanning direction, was invented.
At the same time, Dr. Norikazu Sawazaki and other engineers at Toshiba Research & Development Center developed a helical video tape recorder (VTR). As in the helical VTR, if color filters could be placed at an angle to the scanning direction, the three primary colors would be able to be efficiently obtained. The best way to achieve this was through frequency interleaving, which allowed different frequencies to be shared with luminance signals. In addition, a single frequency could be shared between two color signals if the frequency interleaving method was used. Compared with the conventional method, which simply multiplexed red and blue signals in the frequency bandwidth, frequency interleaving was an innovative method for efficiently utilizing various frequency bands.
The next step was to incorporate the color stripe filter into a camera tube for mass-production. Most camera signal processing circuits used semiconductors, whereas camera tubes were still of the cathode-ray type. They were called vidicon tubes, and their operating properties continually changed–as though they had a life of their own–depending on their temperature and age. In addition, it was very difficult to maintain consistent color image quality because characteristics varied from tube to tube.
Product design had started from scratch in order to launch the color version of the home-use video camera on the market, and cost reduction would help to achieve this goal. So a special development, design, and formulation project was organized, in which the researchers determined which technologies would be most suited to mass-production. Production became possible in the summer of 1973, and the world's first one-tube color home video camera (model IK-12) was commercialized in 1974.
World's First Microcomputer-Based Digital Controller
Digital control contributes to energy saving, pollution prevention, and productivity increases in all industries.
Toshiba developed the TLCS-12 12-bit microcomputer as an electronic engine control for Ford Motors in 1973. The computer was designed for industrial applications such as process control, which required a measurement accuracy of 0.1%. In addition, it was equipped with a CPU and peripheral LSIs and was designed to withstand severe environmental conditions, including both temperature and humidity fluctuations. Engineers were pleased to learn that the size of the computer had been reduced to a palm-size unit.
The company soon launched an application development project for industrial control systems and in June 1975 successfully developed the world's first digital controller, named TOSDIC™, consisting of a conventional analog controller combined with a microcomputer.
Japanese industries expanded rapidly in the 1970s. As steel and petroleum production facilities became larger, more complicated plant operating systems were required in order to improve productivity, save energy, and prevent pollution. The demand for process computer-based digital control systems rapidly increased, because analog control required an individual controller to control each variable (e.g., temperature and flow rate). In the case of digital control, however, a problem in one computer could lead to the failure of the whole plant. Engineers therefore had to create a reliable system while keeping the economic efficiency of the facility in mind.
Digital controllers at the time were distributed systems consisting of a control station incorporating a microcomputer, and loop stations to monitor and operate up to eight control points. Since the digital controller was easier to use, monitor, and maintain than the previous system, the new system was accepted by industry as an innovative product surpassing the analog system in terms of reliability and economy. The controller was further developed into a one-loop controller in 1979, in which each of the loop stations was equipped with an embedded microcomputer.
The digital controller improved the quality of control of each control loop and was capable of performing complicated multivariable control. It was particularly useful in the combustion controls of boilers and reactors, as exemplified by the Double Cross Limit™ combustion control system that was developed to maintain the air/fuel ratio within the optimal combustion values, regardless of changes in combustion capacity. These systems contributed greatly to pollution prevention, energy saving, and productivity increases at industrial plants. The digital controller system was employed in most industrial sectors, including the iron and steel, petrochemical, thermal power generation, and water supply/sewage industries, and Toshiba received the Mainichi Industrial Technology Award for the controller in 1981.
In the 1980s, there was a growing need for high-mix, lowvolume production and flexible automation. To respond to these market requirements, Toshiba developed a CIE integrated control system called CIEMAC™, the term CIE being derived from a combination of computer (C), instrumentation (I), and electrical control (E). Technologies cultivated during digital controller development, including microelectronics, control, and information technologies, allowed microcomputers to be applied in other instrumentation equipment including rolling measurement instruments and electromagnetic flowmeters.
World's First Microcomputer for Automotive Engine
Ford unexpectedly sends Toshiba request to join project related to the US Clean Air Act.
In the 1970s, semiconductors rapidly replaced electronic tubes in general machinery and equipment control. Although automobile control still depended mostly on mechanical parts, the industry was expected to join the semiconductor era before long. At the time, Toshiba had a close relationship with Ford for the supply of rectifier diodes for automobile AC alternators. In March 1971, Ford unexpectedly sent a set bulky specifications asking Toshiba to join a project to make an electronic engine control (EEC) in response to US Clean Air Act (sometimes known as the Muskie Act). The project had begun six month before and RCA and Motorola were already conducting a feasibility study.
Ford's request came with only simple specifications for the electronic engine control, and Toshiba had to exert considerable effort to meet their request. Toshiba presented several proposals and Ford was most interested in Toshiba's microcomputer engine control. At the time however, Intel's 4-bit microprocessor has just come out, and Digital Equipment Corporation's minicomputer (PDP-11) was popular but expensive at USD10,000. It was 1.8m tall and 80cm in width and depth, and an air-conditioned room was necessary for installation. However, Ford wanted a microcomputer as capable as DEC's, at only USD100, and wanted it to fit in a limited area of the engine room and operate in conditions of severe vibration and heavy temperature fluctuation. For this company-wide project, Toshiba hastily organized a special development team in the electronic division to start building an LSI microcomputer. The first hurdle was a functionality test at Detroit, US. Thanks to the extensive effort of Toshiba's system designers, a -box-sized bread board was completed in summer of that year, and the breadboard was combined with Ford's equipment to conduct an on-vehicle test. The trunk of the initial test vehicle was filled with the engine control system.
The next step was to build an LSI circuit based upon the breadboard design. Those was successfully done by LSI process team worked day and night without CAD software or other automated tools, and without any failure succeeded in putting the LSI computer system into operation.
The next issue was mass production of the LSI. Due to the economic downturn caused by the first oil crisis, and the relaxation of the Muskie Act by US Congress, Toshiba had to make a decision on whether to begin mass production of the LSI or not, without receiving a formal order from Ford. As Ford had not made a firm commitment yet, much criticism was madeat those wishing to continue the project. However, Toshio Doko, chairman at that time, made the final decision to continue the project, and production began. The product passed all kind of heavy durability tests in 1976, and the company started to supply computers the next year. The electronic engine control was first incorporated into Ford's Lincoln Versailles and was afterwards adopted in many other models. The development of the electronic control engine (EEC) opened a new era in automotive electronics.
World's First High-Resolution Electronic Scanning Type Ultrasound Diagnostic Equipment
Toshiba's development of an original electronic linear scanning system for the abdominal region and an electronic sector scanning system for the heart provided greatly improved resolution compared with conventional products.
Ultrasound diagnostic equipment uses an ultrasound beam to scan the interior of the human body by means of a probe applied to the body surface, and displays cross-sectional images of the internal organs. From the brief lapse of time required for the ultrasound beam emitted by the probe to be reflected from each layer of an internal organ, distances are calculated and processed as image data. In 1971, the Electronic Device Research Laboratory of the Research and Development Center (currently the Corporate Research & Development Center) started conducting research on how to represent the moving internal organs of the body as image data.
The first prototype electronic linear scanning system for gallbladder examinations was completed in 1975, with the simple target of visualizing gallstones. However, although the system obtained clear images of a hollow experimental sponge, problems were encountered when visualizing a gallbladder. There were large variations in the sensor transmission and receiving properties and in the characteristics of the probe circuit components, and the design of the system for increasing the resolution was also found to be insufficient. These experiences revealed that it would be difficult to commercialize a product, but when another company started to sell electronic scanning type diagnostic equipment at around the same time, the urgent need to achieve commercialization became apparent. As the mission of the Research and Development Center was to connect original research to business opportunities, it was decided that full-scale efforts would be devoted to commercializing an original system.
The images produced by the product already released by the other company were not clear enough to be used for medical diagnosis, so we decided to develop an electronic linear scanning system for the abdominal region with high resolution that no other company possessed. Various technologies were incorporated into the system including subdicing, which reduced image-degrading sidelobes to 1/100 their former level; electron convergence, which converged the ultrasound beam within the surface of the region being scanned; the use of a small-angle sector, which doubled the scanning line density; and an integrated cutting method, which made it possible to uniformly manufacture the array oscillators with their electrodes. Also, with commercialization in mind, the properties of the components and circuits were thoroughly investigated to ensure the consistent performance of all channels at all times.
In 1976, the second prototype was completed and tested in a joint research project with the Kanto Central Hospital. The newly developed system successfully accomplished visualization including gallstones moving in a gallbladder and a fetus moving in the body of an expectant mother. Vivid images were obtained that had never been seen before, and one of the participating doctors reported that he was so moved by the experience that he started shaking. In August the same year, the first product (SAL-10A) attracted considerable attention when it was exhibited at the World Congress on Ultrasound in Medicine and Biology in San Francisco. It was then demonstrated at various hospitals in the U.S., where it received high evaluations for its remarkable image quality. After that, that SAL-20A model was developed as a much more compact version and sold throughout the world. The SAL-20A was widely acclaimed for its superior features, and was also exhibited at the U.S. Smithsonian Institution.
In addition to linear scanning of the abdominal region, there is another ultrasound beam scanning method called sector scanning. This performs scanning as though looking through a gap in the body at the heart surrounded by the lungs and ribs. In 1976, when our company developed the electronic linear scanning system for the abdominal region, another company commercialized an electronic sector scanning system for the heart. However, some of the components of that product had to be adjusted at the time of operation and it was not yet sufficiently useful as a finished product. We decided to create our own sector scanning type ultrasound diagnostic equipment that would be simple and require no adjustments as a basic policy, and started the development work. The key technology in this case was a variable delay circuit, which was necessary for sector scanning. Trial manufacturing was carried out with cooperation from a components group, but the circuitry was complicated and commercialization was abandoned for some time. Later, however, the concept of a read-only memory (ROM)-controlled delay line with high accuracy and a simple configuration was born, and the equipment was completed in May 1977.
World's First SAW Device for TV Receivers
SAW devices surpassed LC filters in performance but realizing their practical use was difficult.
Single-crystal growth technology and unique filter design opened the door to production.
A surface acoustic wave (SAW) device consists of a reflective pattern formed over a piezoelectric substrate and two thin, comb-shaped, metallic transducers called interdigital transducers (IDTs). The device is used to selectively filter out electrical signals at specific frequencies. A SAW is a wave of mechanical vibration that travels along the surface of a solid substance. By placing transducers on the surface of a piezoelectric substrate, electrical signals can be converted into acoustic waves. At high frequencies, a SAW device produces less transmission loss on the substrate, and the reflection transducer can more efficiently reflect waves from its extremely sensitive surface. A SAW device makes use of the property that the efficiency of digital-analogdigital energy conversion depends on the frequency imposed by the IDTs, and on the SAW resonance phenomena in the reflection transducer.
In 1977, Toshiba was the first company in the world to mass produce SAW filters for use in intermediate-frequency filters for TV receivers. In order to produce these filters, the company had to grow single-crystal lithium tantalite (LiTaO3) into piezoelectric SAW crystals, establish a new processing technology and determine the correct crystal cut angle, and develop a comb-shaped transducer design technology to determine the precise phase characteristics of the filter amplitude. In order to determine the phase characteristics, engineers looked for the causes of interference in surface acoustic waves and formulated methods to compensate for deterioration characteristics in the targeted frequency range. From this, an automatic design method was developed by which the design could be completed more efficiently in a short time.
Toshiba was also the first in the industry to mass produce radiators making use of SAW resonance phenomena and low-loss high-frequency filters, which contributed to the simplification of beeper circuits and made video tape recorder (VTR) modulators compatible with integrated circuits. Research into SAW filters continued as higher frequency bands were required and a lighter, more compact version was needed for mobile communication equipment. Today, the SAW filter is one of the key components in mobile phones.
By incorporating the reflection transducer in the internal digital transducer, surface acoustic waves could be transmitted in a single direction, and Toshiba's engineers were able to successfully build SAW devices with low transmission loss. The mode multiplexing filter structure was developed to achieve wider bandwidths, by placing a number of IDTs between the reflection transducers and integrating a higher order resonance mode inducer. As a result, low filter loss and wider bandwidth were achieved. Since the center frequency of a SAW filter is determined by the space between the IDT wires, microprocessing technology for IDTs became essential to obtain higher frequency bands. By making use of dry etching technology in semiconductor processing, mass production of 0.4 μm wire widths and 2.5 GHz filters was made possible, and these new filters covered the frequency bands assigned to third-generation mobile phones (W-CDMA) and wireless terminals (Bluetooth).
Toshiba developed dual filters consisting of two filter chips in one package and, in response to market demand, successfully implemented chip-scale packaging (CSP). With digital televisions dramatically changing the world of media, the line between communication and broadcasting is becoming unclear as TV tuner functions are being incorporated into mobile phones, mobile computers, and wireless terminals. Small and thin SAW devices, with their rapid frequency response characteristics, have contributed to the increased sophistication and size reduction of many such products.
World's First Vector-Control Inverter
The desire to control AC motors as freely as DC motors is fulfilled by using vector operation, opening up a new era of AC variable-speed motor drives.
In 1979, Toshiba implemented the world's first vectorcontrol AC variable-speed motor drive, an inverter and induction motor combination designed to provide highperformance control, in a large-scale factory. The company won the “Ten Great New Products of 1979” award from the Nikkan Kogyo Shimbun (Business & Technology Daily News) in recognition of its vector-control inverter for driving large-scale paper machines.
Until then, DC motors had been utilized in variable-speed motor drives to provide high-performance control. The output of DC motors can be controlled freely according to the DC voltage level. However, these motors also have to supply power to rotating parts and therefore have a complex structure. On the other hand, AC motors (induction motors) need to power only the fixed parts. They are simple in structure and require little maintenance, but controlling the AC voltage and frequency with an inverter results in transient vibration, and it takes time to stabilize the output. A concept had been developed to control the AC vector according to the magnetic flux vector produced by the induction motor, but it was difficult to detect the magnetic flux directly and the concept failed to reach the production stage. In 1978,Toshiba announced that it had found a way to determine the AC vector during operation, solving the detection problem, and in the following year implemented a practical vector control system in a 500 kW large-capacity motor drive.
Although it had been considered too early and risky to adopt this technology in 500 kW machines, the drives were used in a paper plant and operated smoothly with the help of elaborate vector-control design and fine tuning. This opened up a new era of AC variable-speed motor drives. Toshiba deployed its microcomputer-based digital controls ahead of other companies, and its AC motor drives were installed in steel plants with capacities of more than 10,000 kW. As a result of Toshiba's innovation, Japan became the world leader in AC variable-speed motor drive technology and DC motors were rapidly replaced by AC motors.
Today, this technology has become the standard control method. Vector control is implemented not only in the industrial sector but in many other fields, forming the basis of AC motor control in various motors of differing capacities including induction motors, synchronous motors, and permanent-magnet motors.
For example, the world's first inverter air conditioner was developed by Toshiba in 1982, and the introduction of vector-control technology further reduced noise and power consumption. Toshiba also adopted vector-control technology in its elevators and developed the world's first inverter-controlled high-speed gearless elevator in 1983, which simultaneously offered both high speed and comfort. And in the railway sector, vector-control technology allowed the development of the regenerative brake, effective to zero velocity, as well as a function to quickly respond to idle running of wheels.
World's First Bulb-type Fluorescent Lamp, “Neo Ball” (Ball-shaped)
An important point was how small we could go.
We finally succeeded in fitting Neo Ball in a ball-shaped glass with a diameter of 110 mm.
Ever since Japan's first general incandescent lamp was brought into practical use in 1890, the nights have become brighter and the living environment has significantly improved. In 1940, fluorescent lamps were produced for the first time in Japan as a new source of light. This type of lamp was well received by the public because it was five times more luminous than an incandescent lamp and lasted five times longer.
However, although these fluorescent lamps saved energy and lasted for a long time, they were only available in bar or torus shapes and their size did not allow them to be directly attached to incandescent lamp sockets. Therefore, lighting devices with incandescent lamp sockets that could not accept fluorescent lamps did not achieve energy savings, and users of incandescent lamps had to put up with their disadvantages of short life and the need to replace bulbs frequently.
The first oil crisis in 1973 had a great influence on life in Japan. People involved in the lighting industry, engineers in particular, worked hard to find a way to make a fluorescent lamp with high luminous efficiency into the shape of a bulb. A large fluorescent lamp with a bulb base was developed, but consumers never took to it.
A fluorescent lamp that actually looked like a bulb needed to be developed. There had been one idea to create a “bulbtype fluorescent lamp” by bending a fluorescent light tube into a smaller configuration and combining it with lighting equipment so that it could be inserted in light sockets, but it took a long time before Toshiba decided to start trial production.
Thanks to advancements in glassmaking technology and materials, including fluorescent substances, in 1978 a trial production run was conducted to assess the feasibility of the lamps. First, a thin, bar-shaped fluorescent lamp was bent and equipped with a stabilizer. It was then enclosed in a plastic ball-shaped cover. The test showed that temperatures within the assembly rose significantly due to the heat being generated by the lamp and stabilizer, so the product could not be commercialized.
The lamp became slightly more practical when a number of small holes were made at the top and bottom of the plastic cover, but a glass globe could not be employed because of those holes and the engineers had to use polycarbonate resin instead. Improvements were also made in the diameter, gas pressure, and electrodes in order to optimize characteristics such as luminosity, starting characteristics, and performance life. The major focus was on how far the lamp could be downsized, and at last the lamp was successfully placed in a 110 mm-diameter ball.
Finally, in July 1980, the world's first bulb-type fluorescent lamp, called Neo Ball™, was put on the market. It achieved great popularity despite its high price. In order to further improve marketability and promote the dissemination of this lamp, the globe had to have an enclosed structure to prevent insects and dust from entering through the air holes and the product's appearance had to be redesigned. Engineers found after a number of tests that these goals could be achieved by depositing a substance called indium close to the electrode. This technology helped to reduce heat generation and improve luminosity, and also made it possible to use a glass globe with an enclosed structure.
Toshiba then succeeded in realizing an electronic lighting circuit and commercialized the lighter and brighter electronic Neo Ball™ in 1984, before any of its competitors could release a similar product.
World's First Microprocessor-Based Numerical Relay
Through active research on a numerical protection relay incorporating a microcomputer both in Japan overseas, Toshiba commercialized the world’s first microprocessor-based numerical current differential protection relay.
The first scientific paper describing a numerical relay is considered to have been a report by G. D. Rockefeller of the U.S., which was published in 1968. This was before the arrival of microcomputers, and research was being conducted throughout the world on the operation of protection relays using large-scale process computers, including by our company. These efforts were not yet at the level of practical realization, however, because the scale of the devices was too large and the speed of operation was insufficient. The situation changed with the appearance of microcomputers, when the feasibility of the numerical relay rapidly increased. In the latter half of the 1970s, current differential protection systems became a target of research. The current differential protection system is a highly sensitive and highly reliable system for detecting and protecting against faults in power systems. When the sum of the current flowing in from each terminal of a power transmission line is zero, the system judges that there is no fault, whereas in the event that the value is not zero, a fault is judged to have occurred. In addition to analog frequency modulation (FM), digital pulse-code modulation (PCM) was also researched as a method of data communication for this system. A microprocessor-based numerical current differential protection system using PCM communication performs digital conversion by sampling after synchronizing the instantaneous value of the current of each terminal, requiring highly advanced technology. Basic research on a microprocessor-based numerical current differential protection relay of this type, also referred to as a PCM relay, had been carried since the early 1970s. After several field tests, the design progressed to the point where the protection function could be maintained for a long period with a high degree of reliability even under the high-voltage and high-current conditions of an electrical substation and in various temperature environments. In 1980, the world’s first microprocessor-based current differential relay, developed by our company, was applied to the 275 kV Azusagawa transmission line of The Tokyo Electric Power Company (TEPCO).
One of the key features of the PCM current differential relay is its sophisticated built-in function for out-of-step detection. In the event that any of the generators steps out due to an inability to maintain synchronization with the system, the voltage becomes zero at some point in the electric power system at the time when the generator phases are reversed by 180°. This point is called the out-of-step center. When an out-of-step has occurred, stable operation of the generator can be continued by isolating the system at the out-of-step center. A PCM current differential relay uses the transmitted bus voltage phase information of the other terminals to directly compare the voltage phase at both ends of the line and, when it judges that an out-of-step center has entered the line from the 180° reversal of both phases, reliably isolates the system at the out-of-step center.
These functions of the PCM current differential relay such as communication error detection capability, out-of-step detection by voltage phase comparison, and so on cannot be easily realized by the FM current differential relay. As a result, the PCM current differential relay has now established its position as the most reliable transmission line protection system, and is used throughout Japan in power systems ranging from 66 kV systems to extra-highvoltage trunk power systems.
The evolution of microprocessor-based numerical type protection relays, which began with the PCM current differential relay, has been gradually expanding to other areas including circuit selecting protection relay for the 66 kV Yokaichiba transmission line, which was also introduced in 1980. However, the first-generation DI type numerical relay suffered from the problem of heat generation due to its use of a bipolar type device. This problem was solved by the use of a special heat pipe.
Remarkable progress was seen in arithmetic devices and, a few years later, a metal-oxide semiconductor (MOS) type high-speed arithmetic device appeared that generated less heat. This triggered a shift to the era of the secondgeneration DII series MOS type numerical relays beginning in 1985. Since that time, their application has rapidly expanded throughout Japan and they have been playing the leading role in the protection relay field.
World's First Residential Inverter Air Conditioner
Initial stage of development saw many compressors broken when used with inverter.
Engineers gave up summer holidays and worked naked in the heat, making prototypes and checking their performance.
In the early 70s, cooling/heating type air conditioners had a limited heating capacity and most of them needed auxiliary heaters in their indoor units to complement their heating capacity.
As energy-saving awareness rose in the wake of the 1973 oil crisis, the emergence of new technology was long awaited for reducing energy loss by a continuous control of compressor capacity so that the conventional on-off control for temperature adjustment was to be replaced. Many had predicted that the use of an inverter, or frequency converter, would be an optimal choice to serve the purpose, but inverters in those days were too large and expensive to be built into air conditioners. Despite these challenges, Toshiba, with a state-of-the-art high-power transistor and microprocessor-controlled sinusoidal pulse width modulation, achieved a significant downsizing in its inverters. An inverter whose size and weight was only one-sixth that of a conventional inverter, was instrumental in Toshiba's launch of the world's first air conditioner for commercial use in December 1980.
Toshiba's next quest was to apply this inverter technology to residential air conditioners in the hope that the technology would also allow flexible capacity changes for residential air conditioners. The development started in January 1981. The biggest challenge was the price and size of the inverter, an electric circuit used to control the rotation speed of a compressor; and in addition, the engineers also had to deal with other big challenges. Prior to the emergence of inverter air conditioners, air conditioners operated with a compressor, the heart of an air conditioner, which rotates at a fixed speed. However, with this new inverter technology, the engineers did not know what trouble or damage to expect on the compressors that run at variable speeds controlled by the inverter.
So, the engineers started the development of an inverter air conditioner with trial and error, witnessing many compressors broken through the course of their development activities. The first issue found was that the compressor saw lubricant oil flowing out from its mechanical parts when operated at a high speed and lacked lubrication when operated at a low speed. The second problem was found in the discharge valves; all of them were found broken, resulting from an increased intensity of the impact on the valves as the roller speed increased. Some vane wear was also found due to a similar cause. The third problem was an abnormal high-pitched noise that occurred during the operation. The engineers worked hard to overcome these problems one by one.
Since residential air conditioners operate on AC 100V, the voltage doubler rectifier was utilized to convert the power into AC 200V for supply to the compressor. To reduce the size of the inverter, a larger transistor (so-called giant transistor) was needed. The transistor was an important component for controlling via computer the circuit connecting the compressor with the inverter, and development of that transistor was done in cooperation with the engineers in the semiconductor division.
The compressor and inverter were nearly complete by the end of August 1981. The size of the inverter was reduced to one-third that of a commercial inverter, which was small enough to be mounted above the compressor in an outdoor unit of the residential air conditioner, and the cost was reduced to 40% of the original value. The engineers also worked through challenges in developing the refrigeration cycle. They gave up their summer holidays and worked naked in the heat as the factory had a power outage due to some renovations in progress, making prototypes, and checking their performance.
The product was finally completed in September 1981, and received a rave review after a press release on November 12, 1981. For the revolutionary innovation in the history of air conditioning technologies, Toshiba won the Ichimura Industrial Award in 1984 from the New Technology Development Foundation. The product was one of the first-ever registered as “One-Step on Electro-Technology” in 2008 by the Institute of Electrical Engineers of Japan. Then, in 2020, it was certified by IEEE, the Institute of Electrical and Electronics Engineers, as an "IEEE Milestone".
World's First Inverter-Controlled High-Speed Gearless Elevator
Inverter control was an essential condition for achieving smooth riding comfort in high-speed AC motor-driven elevators.
Toshiba started manufacturing and selling elevators in 1966 and installed its first low- to medium-speed elevator at Kawai Musical Instruments Mfg.'s Maebashi facility the following year. In 1970, the company built its first Ward Leonard control-type high-speed elevator for the Toranomon 17 Mori Building. The elevator used a DC motor in its hoist. This type of high-speed elevator required advanced technologies in its construction. Vibration of the elevator during the ride had to be reduced as much as possible to maintain comfort while moving at high speed. It also had to stop accurately at each designated floor. These requirements were satisfied by using Ward Leonard control. Each DC motor was provided with a DC generator driven by a 3-phase induction motor, and the hoist was controlled by varying the voltage applied to the DC motor. However, Ward Leonard control was expensive and a great deal of space was required for installation.
In order to solve these problems and achieve both comfort and silence during operation, Toshiba developed a gearlessdrive hoisting motor without a reduction gear. This motor employed the static Ward Leonard control method, which utilized a thyristor for power conversion. The first static Ward Leonard control high-speed gearless elevator was built at the Daiichi Seimei Building in Shinjuku, Tokyo, in 1980, and an ultrahigh-speed gearless elevator was installed at the Toshiba Building in Tokyo's Shibaura district in 1984.
However, the static Ward Leonard method, which controlled the DC motors, caused power distortion and required a large power-supply capacity to improve the power factor. To overcome these shortcomings, Toshiba introduced vector-control technology and inverter technology, which had been rapidly developed in response to the need to save energy, in order to control AC induction motors with more accurate position control. The company employed a baskettype induction motor for the traction machine, and completed the world's first inverter-controlled high-speed gearless elevator in 1983, with the inverter performing variable-voltage/variable-frequency control.
While the elevator was traveling at full speed, the induction motor rotated at only a few revolutions per second, so a brushless resolver was employed to accurately detect motor rotation. Slip frequency control-type vector control was combined with inverter control, and the company was able to stabilize torque control (including stop control) and establish a method to freely control drive speed from ultraslow to full speed. In 1985, Toshiba installed its first inverter-controlled high-speed elevator at the research laboratory of Toho Gas Co., Ltd. in Aichi Prefecture.
The company continued research on thyristors for use in inverter control and dramatically enhanced their switching capacity. This resulted in the development of insulated gate bipolar transistors (IGBTs) at the end of the 1980s. The IGBT realized increased switching frequency and reduced magnetic noise in the motor, which eliminated the need for a filter circuit and resulted in a more compact system. The IGBT also allowed the development of a small, highly integrated and highly sophisticated all-digital control device, consisting of the combination of a high-speed processor, specially customized gate arrays, and a circuit capable of controlling large currents of several kHz. Today, the inverter-controlled gearless drive system is applied in high-speed elevators worldwide.
World's First Non-latchup IGBT
Outside-the-box thinking leads to a solution for the latchup problem during development of the insulated gate bipolar transistor (IGBT).
The power semiconductor device is a key component in all fields of power conversion. Toshiba started the development of a high-power gate turn-off (GTO) thyristor in the early 1970s, and discovered that the obstacle preventing its practical application was current concentration, or current hogging, in the turn-off state. The company therefore decided to develop a new device to solve this problem.
In 1977, Toshiba put a 1.3 kV-600 A GTO thyristor on the market, and in 1979 delivered Japan's first variable-voltage variable-frequency (VVVF) inverter using GTO thyristors to the Osaka Municipal Transportation Bureau, for use in electric railways. GTOs are commonly used not only in electric railways, but also in variable-speed control for industrial AC motors and large power-inverter power supplies. In the late 1970s, Toshiba began to develop a direct-light-triggered high-power thyristor, and in 1981 launched on the market a device using a high-output LED as a light source.
In the early 1980s, following the invention of the giant transistor and the GTO thyristor, inverter technology progressed to the extent that inverter-equipped home air conditioners were able to be commercialized. High performance, reliability, low noise, and compactness were essential in switching devices for power conversion equipment such as elevator motors and electric railways, and particularly for equipment that required switching at frequencies higher than the audio frequency range. Metaloxide- semiconductor field-effect transistors (MOSFETs) were used as high-speed switching devices at the time. However, they were limited in terms of current and voltage, and were therefore only used in lower voltage equipment (up to AC 200 V).
Almost all of the world's semiconductor manufacturers were competing in the development of new devices, and in 1982 a new insulated gate bipolar transistor (IGBT) was announced by General Electric (GE). This consisted of a vertical N-channel MOS structure applying drain layer conductive modulation, achieved by adding a P layer to the drain side. However, GE's IGBT structure inherently contained a parasitic thyristor action that could cause the device to switch on after latchup. This made it impossible to cut off a high current, and so the IGBT could not be put to practical use.
At the time, the Toshiba Research & Development Center (currently the Corporate Research & Development Center) had started research on GE's IGBT structure based on the expectation that the device structure might have the potential to replace the bipolar giant transistor. Comparing data using a two-dimensional device simulator, the researchers discovered that a simple stripe pattern mask prevented unexpected latchup rather than the mesh pattern mask that was generally used in MOS devices at the time.Shortly after that, the researchers came up with another idea. They decided to design the MOS saturation current so as to be lower than the current at which device latchup occurred. As a result, they demonstrated that a non-latchup structured IGBT was capable of cutting off high currents, leading to the practical use of this device in the market and mass-production.
In 1984, Toshiba developed a fracture-resistant non-latchup IGBT by designing a new structure, and presented it at the International Electron Device Meeting (IEDM) that year. The following year, in 1985, the company announced the commercialization of its IGBT. The device, a world first, received the I-R 100 Award and the Okochi Memorial Technology Prize and was also honored as “Cornerstone of Electro-Technology” by the Institute of Electrical Engineers of Japan in 2010.
World's First Laptop PC
Combining expertise to pursue portability, smaller size, and power saving, Toshiba pioneers laptop PCs, creating a new market.
Beginning around the mid-1970s, personal computers became increasingly popular among hobbyists, including in the form of assembly kits. Businesses began to use PCs in the 1980s, and the market grew rapidly. The IBM PC, developed by IBM in 1981, became the industry norm and dominated the global market as the first full-fledged business computer. Toshiba, which had been expanding its scope of business to small machines and office automation equipment, released a Japanese-language word processor called the JW-10 in 1979, followed by the Rupo series in 1985. These products were successful, but Toshiba had fallen behind other companies in the PC business. Desktop PCs with proprietary specifications, no matter how unique, were not adopted by the market unless they were compatible with standard machines; i.e. the IBM PC. Toshiba's PC division was operating at a deficit and the company was on the verge of quitting the business.
The only way for Toshiba to continue in the PC market was to introduce an innovative computer that the market had never seen. Toshiba believed that it would have a popular product if it pursued mobility, smaller size, and power saving to make a portable computer that was fully compatible with standard machines. The company also knew it would be able to take advantage of technologies it had accumulated in the development of Japanese-language word processors. A team of engineers started development of a laptop PC in April 1984, according to the specifications and development schedule decided by the team leader.
At first, the engineers thought that the project would be impossible to complete. However, they were eventually able to overcome the various problems and somehow achieved their goal, thanks to some technical assistance from Toshiba's Ome Operations facility as well as the fact that most of the key components that went into building the smaller laptop PC were developed in-house, including semiconductors, a 3.5-inch floppy disk drive, and a large liquid crystal display. The new product weighed only 4.1 kg, one-seventh the weight of a contemporary desktop computer.
In April 1985, Toshiba released the world's first laptop PC, the T1100, in Europe. The company had given up on the PC business in the U.S., and the Japanese market at the time was dominated by the NEC PC-98 computer lineup, which was not compatible with Toshiba's machine. The T1100 was an innovative product but had some problems. It used a 3.5-inch floppy disk drive, not the 5-inch type more commonly in use. The machine was also not very affordable (costing around 500,000 yen). Some people thought that it was too early to launch the product, but the head of Toshiba's PC business in Europe believed in the potential of laptop PCs and strongly promoted their sales. He convinced customers, leading software makers, and sales agents that desktop computers would soon be replaced by laptop computers. He was able to achieve an annual sales target of 10,000 machines, a feat that was remarkable for Toshiba's PC division at that time.
Encouraged by the success of the T1100 in Europe, Toshiba started selling laptop PCs in the U.S. and Japan the following year. The T1100 was modified and renamed the T1100Plus, and the even more advanced T3100 (J-3100 in Japan) was developed in 1986. The T3100 was equipped with the latest technologies, including a plasma display and a hard disk drive. The product earned wide acclaim as the “king of laptops” immediately after it was put on the market, and won a number of awards.
Through its technical innovation, Toshiba continued to lead the portable PC market, and was also able to make major contributions to the component market. In 1989, the company received the Okochi Memorial Production Award from the Okochi Memorial Foundation for these new technologies.
World's First Successful Test of the Light-Triggered Thyristor in an Actual Transmission Line System
The light-triggered thyristor, which does not require a power supply for its insulated gate, is a key device in the field of power electronics.
Power semiconductor devices are semiconductor devices such as diodes and transistors that are used in power supply and inverter applications, where they perform various functions including AC-DC conversion, voltage step-up/step-down, frequency conversion, and so on. In 1972, upon receiving a strong request from what was then the Systems Department of the Heavy Electronics Division, the Electron Devices Laboratory of the Research and Development Center (currently the Corporate Research & Development Center) began the full-fledged development of a high-power gate turn-off thyristor (GTO) (a thyristor that can be turned off by means of gate control). Scientific papers describing this type of device had already been published in the 1960s, and General Electric Company, Westinghouse Electric Corporation, and RCA Corporation in the U.S. developed GTOs in the early 1970s. However, they were unable to obtain the expected performance and either scaled down their activities or withdrew from this field. A number of Japanese companies also worked on GTOs, but all of their development efforts failed.
Toshiba's Semiconductor Division had also been engaged in the development of a small-sized GTO, but had decided to abandon this work due to insufficient yield rates and therefore had a cautious view of this field. Even so, the Systems Department made their strong request for renewed efforts with its sights set on power converters for use in industrial applications and electric railway systems. The president of the company agreed with this view and gave instructions for a new clean room to be established for this purpose, with the Systems Department to support the development work in cooperation with the Semiconductor Division.
The greatest challenge in this project was to find a way of increasing the turn-off current, with the aim of expanding the range of applications. In 1976, the company broke the world record for withstand voltage and current rating by a large margin and, in 1978, announced the development of a 2,500 V-600 A GTO with double the previous withstand voltage. This was followed by a 4,500 V-3,000 A GTO, which was adopted for the Nozomi Shinkansen ("Bullet Train") cars in Japan as well as for the locomotives of a rapid rail transit system in Europe and greatly contributed to the development of Toshiba’s power electronics-related business.
At around the same time, the light-triggered thyristor, which can be triggered by a light-emitting diode (LED), was under development. Compared with conventional electrically triggered thyristors, it realized greater miniaturization of equipment and the use of fewer components, leading to improved reliability. Upon receiving another strong request from the Systems Department, which wanted the extra-highvoltage thyristor valves used in frequency converter stations and DC power transmission systems to be exclusively of the light-triggered type, development efforts in this field were initiated in 1978. Already a 4,000 V-1,500 A electrically triggered thyristor had been commercialized, and the development of a high-power light-triggered thyristor using general-purpose LEDs as the trigger with nearly 100 times the light gate sensitivity while maintaining the same electrical characteristics was a risky venture.
From December 1983 to February 1985, a test was conducted on an actual transmission line system at the Sakuma Frequency Converter Station of Electric Power Development Co., Ltd. with as many as ninety 4,000 V-1,500 A light-triggered thyristors connected in series. The success of this project, the first time in the world that the light-triggered thyristor had been tested in an actual transmission line system, was a deeply moving experience for the people involved, and demonstrated the feasibility of DC power transmission using this device.
On the other hand, from around 1981, when the development of high-power light-triggered thyristors of 4,000 V capacity had reached a certain point, research with the objectives of realizing higher-output LEDs and higher withstand voltages also began. After trial manufacturing of more than 10 types of light gate structure, the company succeeded in the development of a new multistage amplification light gate structure that fully met these research objectives and, in 1982, a device with the world's largest capacity of 8,000 V-1,200 A was exhibited at an exhibition of Toshiba’s technologies. Then, in 1984, an 8,000 V device with an integrated overvoltage protection function was released. Toshiba's 4,000 V-1,500 A devices were widely used for reactive power compensators installed in transformer substations, while our 6,000 V-2,500 A devices were mainly adopted for frequency converter stations and DC power transmission systems, as well as for industrial applications such as converters for motor control in steel works. In 1990, the Semiconductor Division developed a 6,000 V-2,500 A light- triggered thyristor with an overvoltage protection function.
World's First Red Laser Capable of Continuous Oscillation at Room Temperature
After developing the world’s first red laser capable of continuous oscillation at room temperature, Toshiba again became a global pioneer the following year by developing the transverse mode control structure for application to optical discs.
U.S. physicist Theodore Maiman invented the world's first ruby laser in 1960. In 1962, pulse oscillation of a semiconductor laser was reported. Then, in 1970, continuous oscillation at room temperature was achieved by a galliumaluminum- arsenide (GaAlAs) infrared semiconductor laser. Inspired by these leading-edge technological developments, Toshiba’s Research and Development Center (currently the Corporate Research & Development Center) also started research on semiconductor lasers and, in 1973, succeeded in the recording and reproduction of holograms by semiconductor laser for the first time in the world.
After that, aiming at the application of semiconductor lasers to the optical communications field, our company participated in a large-scale project for the research and development of optical measurement control systems sponsored by what was then the Ministry of International Trade and Industry. Under this project, we conducted research on an integrated-wavelength semiconductor laser in which lasers with different oscillation wavelengths were integrated on the same substrate. A device achieving the integration of five wavelengths was developed in 1983 as a light source for wavelength-division multiplexing (WDM) optical communications, and received high evaluations worldwide.
On the other hand, with the objective of realizing optical discs with higher capacity, Toshiba was independently working on the development of an indium-galliumaluminum- phosphide (InGaAlP) red semiconductor laser. Although the GaAlAs infrared semiconductor laser was widely used at that time for conventional music CDs, optical discs required a semiconductor laser that could oscillate in the visible light region. For this purpose, we concentrated first on laser semiconductor crystal growth technology and in 1985, using a new crystal growth technique called metalorganic chemical vapor deposition, succeeded in developing a red laser capable of continuous oscillation at room temperature for the first time in the world.
We then focused our attention on the process technology for manufacturing the device, and developed a transverse mode control structure. This structure narrows down the emitted light to the extremely small spot necessary for a semiconductor laser serving as a light source for optical recording. As a result, a high-quality beam suitable for use as a light source for optical discs was realized in 1986. Furthermore, in a press release in November of the same year, we announced the successful reproduction of highdefinition optical discs using the red semiconductor laser. Needless to say, this was the world’s first optical disc using red laser technology. Toshiba went on to play a leading role in the formulation of standards for DVD incorporating red laser technology, which were announced in December 1995. This was followed by the commercialization of the world’s first DVD in 1996.
Another field of application of this technology was barcode readers. The red helium-neon (He-Ne) gas laser was already being used as a light source for such devices, and there were expectations that a large market for point of sales (POS) systems could be realized if these lasers were replaced by compact, power-saving semiconductor lasers with the same waveband. The power consumption of He-Ne gas lasers ranged from 10 W to several tens of watts, compared with a level of around 0.1 W for semiconductor lasers. The GaAlAs infrared semiconductor laser (wavelength: 780 nm) for CD use was unable to provide the reflectivity contrast specified in the JIS standards for blue barcodes, but the wavelength of the InGaAlP red semiconductor laser (670 nm) was close to that of the He-Ne laser (633 nm) and was able to satisfy the JIS standards. This InGaAlP red semiconductor laser opened up the large POS market, particularly in the U.S., and for a certain period Toshiba held the top share of more than 90% in this market.
World's First Large-Capacity Ultra-Supercritical-Pressure Steam Turbine
This historically significant technology was featured in “A Century of Power Engineering” in Power Engineering International magazine.
The May 2010 issue of Power Engineering International (PEi), an international news magazine devoted to electric power technology, carried a feature article on worldwide developments in this field over the preceding 100 years (1910 to 2010). Entitled “A Century of Power Engineering,” the article featured around 50 historically significant technologies and events in chronological form. Toshiba was honored with the inclusion of one of its projects: the world's first ultra-supercritical-pressure turbine, which had been developed in 1989. A photograph of the turbine was also shown.
An ultra-supercritical-pressure turbine operates at a main steam pressure of 31.1 MPa, significantly higher than the 22.1 MPa critical-point pressure of water vapor. Such turbines were so named to distinguish them from the existing supercritical-pressure turbines, which operated at a main steam pressure of 24.2 MPa. By 1989, the world had experienced two oil crises and demand for improved power generation efficiency was rapidly increasing. However, after a pilot system in the U.S. malfunctioned, there was some anxiety about whether the state of technology was sufficient to withstand the high temperatures and high pressures an ultra-supercritical thermal power plant would require for improved thermal efficiency. There had been few developments in high-temperature/pressure engineering for more than a decade, but Toshiba's turbine broke through this technological stagnation.
The first two units were 4-cylinder steam turbines built for Chubu Electric Power Company's LNG-fired Thermal Power Station in Kawagoe. They were rated at 700 MW at 60 Hz output, with double-reheat steam conditions of 31.1 MPa/566°C/566°C/566°C (TC4F-33.5 type). Under these steam conditions, thermal efficiency at the generating end of the turbine plant increased to 41.7% from 39.7% for an existing equivalent machine, showing a relative improvement of 5%.
Toshiba made use of the technology in existing intermediatepressure and low-pressure turbines, and focused development on high- and ultrahigh-pressure turbines. The first design change to come out of Toshiba's research and development was the adoption of new 12 Cr steel for all static and rotating parts, in order to reduce the thermal stresses that would accompany increased pressure. The second change was to use new testing equipment to determine the rotor system characteristics in advance, in order to prevent unstable rotor shaft vibration due to ultrahigh-pressure steam whirl phenomena. The final change was to confirm the reliability of the first-stage moving blade, which was exposed to the most severe conditions, by conducting thorough numerical analysis and rotation tests using actual equipment.
This steam turbine has, as expected, continued to operate smoothly for the past 20 years. Toshiba received high evaluations for this achievement, and also received a number of awards in 1991, including the Japan Society of Mechanical Engineers Award and the Institution of Mechanical Engineers (U.K.) Research Paper Award.
After the introduction of these ultra-supercritical-pressure turbines, more efficient combined-cycle systems came into use in LNG thermal power generation systems, and gas turbines began to take over from steam turbines. However, Toshiba's technology continues to be used in coal- and oilfired power plants, which still account for the majority of the world's electric power production, and it is contributing to energy saving and global-warming prevention in Japan, China, and many other countries worldwide.
Toshiba's steam turbine is internationally recognized as having played a significant role in the adoption of steam turbines in the modern world.
World's First Adjustable-Speed Pumped-Storage Generating System
The technology of the adjustable-speed hydroelectric generator, which had been developed 60 years before, was revived as the world's first adjustable-speed pumped-storage generating system.
In a conventional hydroelectric power plant, the generators rotate at a constant speed corresponding to the system frequency (50 Hz in eastern Japan and 60 Hz in western Japan). However, it was known that water turbines coupled to the generators could run with higher efficiency if their rotating speed could be adjusted to conform with variations in the operating head and power output.
Toshiba developed Japan's first adjustable-speed generator (rated 750 kVA), which could run a water turbine at its optimal speed to achieve the best operating efficiency. It went into operation in 1930 at the Yoshino No. 2 Power Station of the Kanazawa Municipal Utility Board (later merged into Hokuriku Electric Power Company). Although it was a highly advanced generator in those days, its technology was not implemented thereafter in other power plants.
With the rapid postwar growth of the Japanese economy, power demand increased significantly. In parallel, the imbalance of power demand between day and night became larger and load fluctuations also became greater. A power generation system must be capable of quickly adjusting to load variations in order to maintain stability of the power grid frequency. Hydroelectric power generation can readily satisfy this requirement because its output can be swiftly adjusted by regulating the flow rate. From the 1960s onward, however, very few sites were available in Japan for constructing large-capacity hydroelectric power plants that could cope with large load variations.
Pumped-storage power plants were therefore introduced as an alternative to conventional hydroelectric plants. Conventional hydroelectric plants use the natural flow of a river to generate electric power, whereas pumped-storage power plants use the water in an upper reservoir pumped up from a lower reservoir during the off-peak period at night. For pumping, this system uses surplus power generated by other generating sources such as nuclear power stations. This means that large-capacity pumpedstorage power plants can be built anywhere, regardless of the availability of a large river flow. Since the power output of pumped-storage plants can be adjusted as quickly as that of conventional hydroelectric plants, they are now playing an indispensable role in Japan for the stable supply of power and maintenance of system frequency.
However, the generator-motors of pumped-storage units have so far mostly been synchronous machines that have to run at a constant synchronous speed. Due to the basic characteristics of pump-turbines, the input power in the pumping operation cannot be changed when the system is running at a constant speed. If it were possible to change the rotation speed, it would be possible to change the pump input. This would make it possible to adjust the balance of power supply and demand and to regulate the system frequency even in pumping operations at night.
Focusing on this idea, Toshiba conducted a joint study with Tokyo Electric Power Company and developed the world's first adjustable-speed pumped-storage system using a generator-motor with low-frequency AC secondary excitation. The first commercial unit was commissioned at the Yagisawa Pumped Storage Power Plant in 1990.
The principle of this adjustable-speed generator-motor was the same as that of the generator installed at the Yoshino No. 2 Power Plant 60 years earlier, except for the use of a cycloconverter as the low-frequency AC excitation system in the new unit. The cycloconverter is a static frequency converter composed of a number of large-capacity thyristors. This adjustable-speed pumped-storage unit is controlled by a high-speed, high-performance digital controller, which allows its input or output to be changed much more quickly than in conventional hydroelectric units. Such fast power control realizes more complex and\advanced control than in conventional units, such as the stabilization of large power oscillations in the grid in the event of an emergency.
World's First LCD TVs with Overdrive Technology
Toshiba's overdrive technology, which reduces the image lag of LCDs and produces vivid pictures, was adopted for LCD TVs throughout the world.
Liquid crystal display televisions (LCD TVs) are now at the forefront of the global TV market. Overdrive technology, which greatly enhanced picture quality, made a major contribution to their commercialization. This technology is now incorporated in almost all LCD TVs, which have created a new market.
In 1988, a number of specialists in materials, devices, circuits, and systems were gathered together as a team at the Research and Development Center (currently the Corporate Research & Development Center), and a project to develop wall-mounted TVs was inaugurated. This marked the beginning of development of LCD TVs at Toshiba. The latter half of the 1980s was a time when LCDs for lap-top type PCs were just starting to appear on the market.
Overdrive technology is an image processing technology for LCDs that accentuates changes in the displayed pictures. Conventionally, the response speed of liquid crystals was slow when dealing with incremental variations in the brightness of a moving picture, making it difficult to follow sharp changes in brightness and resulting in blurred images due to the phenomenon of image lag occurring behind the object moving on the display. Overdrive technology accentuates such changes in advance so as to cancel out this image lag.
At the time when this project began, image lag in LCDs was considered to be caused by the slow response speed of switching between two values—namely, the darkest and lightest levels of brightness—and the switching response speed in the case of half tones, in which the changes of brightness are smaller, was not an issue. The development personnel had already been considering the feasibility of overdrive. However, the maximum voltage of the driver integrated circuit (IC) driving the LCD was fixed, and they realized that this limit would be exceeded if they tried to apply overdrive to the switching of the two values representing the darkest and lightest levels of brightness. They thought that since overdrive was not feasible with a voltage exceeding the upper limit, the only possible approach would be to increase the speed of the liquid crystal material itself to eliminate the image lag.
However, when an experiment was conducted in which response characteristics were precisely measured at all gray-scale levels, the outcome turned the conventional understanding upside down. The results showed that the response speed of the half tones was, in fact, slower, and that large changes in capacity with the movements of the liquid crystals occurred particularly in the case of half tones, generating image lag. In other words, the major cause of image lag in liquid crystals was the slow switching of the half tones. “If we’re dealing with half tones, overdrive can be applied!” Without delay, LCD TVs incorporating this technology were manufactured on an experimental basis and exhibited at the Japan Electronics Show (currently CEATEC JAPAN) in 1990 and the Consumer Electronics Show (CES) in the U.S. in 1991. Visitors were surprised at the high quality of the images with less image lag, making comments such as “Is this liquid crystal?” When the technical details were released in 1992, the improvement in image quality obtained by overdrive technology was even described by the press as “liquid crystal equivalent to a cathode-ray tube.” After enhancement of the memory efficiency for practical application, overdrive technology was incorporated into large-sized LCD TVs from around 2002, and diffused to the extent that almost all LCD TVs, including those manufactured by other companies, are now equipped with it. Although the response speed of the liquid crystal itself has been improving, doubling or even quadrupling of the refresh rate has become necessary to further enhance image quality, and at least double the refresh rate is required for three-dimensional displays. As a result, overdrive still remains an essential technology today. In 2004, Toshiba’s contribution as the pioneer of overdrive technology was recognized when the company received the Special Recognition Award from the Society for Information Display (SID), the world’s largest international society in the field of displays. This was followed in 2007 by the Contribution Prize of the Ichimura Industrial Awards, and in 2009 by the Imperial Invention Prize of the National Commendation for Invention.
World's First NAND Flash Memory
The NAND flash memory created by Toshiba achieved a position as Japan's first global memory standard.
Toshiba to use its own technologies to increase the capacity of NAND flash memory, receiving the Ichimura Industrial Award.
Key requirements of storage devices for digital data include: (1) high reading/writing speeds, (2) nonvolatility, (3) low energy consumption, and (4) low cost. In the past, magnetic media such as hard disks and floppy disks were used. Meanwhile, DRAM memory, which is superior in terms of high-speed processing and is used as the main memory in personal computers and other devices, was not suitable for use as an external storage medium due to the fact that it would lose stored data when its power was turned off (volatility). In addition, existing nonvolatile memory was still inadequate in terms of cost and capacity.
In 1989, Toshiba invented NAND flash memory, which surpassed previous types of nonvolatile memory in terms of both capacity and low cost. Toshiba was first in the world to put this memory to practical use as a semiconductor-based memory optimal for filing applications, by applying to it a serial interface compatible with that used for hard drives. Following its announcement at the IEEE International Solid-State Circuits Conference (ISSCC) in 1989, Toshiba developed file-storage applications for its NAND flash memory, succeeding in establishing its position as the de facto standard in the industry - Japan's first global standard in the memory field. As a core technology of digital homeelectronics products, used as memory in digital still cameras and digital audio players, this NAND flash memory has made major contributions to revitalizing Japanese industry. In April 2000, it received the New Technology Development Foundation's Ichimura Industrial Award - the first time in 28 years Toshiba had received the award.
In 1991, Toshiba announced new specifications for achieving a system completely different from existing memory protocols. It also announced a strategic partnership with IBM of the US for the development of solid-state disks to replace hard disks, and began development of 16-megabit products. The following year, it announced commercialization of its 16-megabit NAND flash-memory products, proceeding simultaneously with mass production at Iwate Toshiba Electronics Co., Ltd. and with market-development efforts. In this way, NAND flash memory became a fully-fledged new business for the company.
In 1995, the company resolved various issues that had made both technological development and mass production difficult, added 32-megabit products to its lineup, and began joint development efforts with Samsung Electronics Co., Ltd. of South Korea. In 1996, it proposed small flash-memory cards it named SmartMedia™, with 16-megabit and 32-megabit products built-in. That same year, a forum established with Fujifilm, Olympus, Sega, and other partners marked the start of the digital-camera industry. This was followed by severe competition between digital cameras using SmartMedia™ and those using the Compact Flash standard proposed by SanDisk of the United States. Development of NAND flash memory has proceeded at a fast pace, with storage capacity doubling every year. This technology has also contributed to creating a market for digital audio players.
In these ways, the NAND flash memory created by Toshiba has achieved a position as Japan's first global memory standard. As Toshiba has used its own technologies to increase the capacity of NAND flash memory, it has created new markets and a highly profitable business.
World's Largest 11MW Fuel Cell Power-generating Plant
Fuel cell power-generating plant receives a high evaluation for its high power-generating efficiency.
Even better efficiency is achieved through polymer electrolyte fuel cells.
Following the first and second oil crises, the Moonlight Plan of the Ministry of International Trade and Industry (MITI) included development of phosphoric-acid fuel cells (PAFCs), which boast high power-generating efficiency and superiority in terms of environmental considerations. These have attracted attention as a fourth type of power-generation technology, in addition to hydroelectric, thermoelectric, and nuclear power.
Toshiba began fundamental research in this field in the early 1960s. Beginning in 1982, it participated in the Moonlight Plan's project to develop pressurized fuel cells as a power source to replace thermoelectric power. A 1 MW plant was installed in Chubu Electric Power's Chita 2 Thermal Power Plant in 1987 for research purposes. In April 1985, Toshiba established a joint venture, International Fuel Cells (IFC), with United Technologies to seek new business for power companies. This joint venture fused United Technologies' fuel-cell technology (then the world's most advanced, and garnered through experience with spacecraft such as the Apollo series and the Space Shuttle) with Toshiba's power-generation plant technology. An 11 MW PAFC plant was delivered to Tokyo Electric Power's Goi Thermal Power Station in 1991. Operating through 1997, this plant was able to confirm the PAFC's high power-generating efficiency and environmental soundness.
Meanwhile, in 1990 a specialized on-site company, ONSI, was established as a joint venture with IFC. Beginning in 1991, 56 units of the semi-commercial PC25A;200 kW PACF, manufactured by Toshiba and featuring built-in reformers and electrical controls, were shipped domestically, to North America, and other markets around the world. These operated for a total of 40,000 hours, the target duration we had set for commercial models. The PC25C, which incorporated further cost and size reductions, was introduced for commercial use in 1996. In 1997, this model received the New Energy Foundation's New Energy Award (in the Commendations for the 21st Century Type New Energy Equipment/System Category). In Japan, this model is used for cogeneration purposes at facilities such as hospitals, hotels, breweries, amusement parks, and watersupply and sewage facilities. Recently, four 200 kW units were installed on the grounds of Expo 2005, held in Aichi prefecture beginning in March 2005, to supply electricity to the Japanese government's exhibition hall in the Expo's Nagakute Area.
In addition, since 1992, Toshiba has participated in the NEDO New Sunshine Plan. As part of this program, it began research and development into polymer electrolyte fuel cells (PEFCs), leading to the completion of a 1 kW class cell stack in 1995. It then began system development efforts, which led to completion of a 1 kW class PEFC cogeneration system for household use in 2000. Beginning in 2002, Toshiba has participated in the PEFC testing and other research projects of the New Energy Foundation (NEF), proceeding with development directed toward practical implementation of this technology.
World's First 550 kV Single-Break Gas Circuit Breaker
The development and practical application of high performance arc-extinguishing chamber of gas circuit breaker is a key technology to realize compact and high capacity substations, and they made it possible to transfer large power to urban area.
Toshiba developed a series of switchgears with higher voltage and current capacity during the postwar era of high economic growth. From around 1970, the company shifted its developmental efforts from air-insulated switchgear to gas circuit breaker (GCB) and gas-insulated switchgear (GIS) systems using sulfur hexafluoride (SF6), which has excellent insulation performance. GCBs with higher rated voltages, such as 300 kV or 550 kV, were initially realized by connecting multiple breaking points in series. However, further downsizing of GCB and GIS became an issue, so the factory and laboratory dealing with these systems worked together to reduce the number of breaking points.
In order to reconfigure a conventional 300 kV GCB with two breaking points into a single breaking point device, it was necessary to double the breaking performance. Moreover, a large-scale specialized test facility was required to perform the verification test of short-circuit performance. The world's largest short-circuit test facility was therefore constructed at Heavy Apparatus Engineering Laboratory, and by fully utilizing this facility, performance of a singlebreak 300 kV interrupting chamber was achieved through our original developmental efforts. We then applied this new technology to the world's first 300 kV single-break GCB, which was supplied to the Shin-Keiyo Substation of Tokyo Electric Power Company in 1982.
By replacing the double-break circuit breaker with the new single-break type, the height of GIS systems could be reduced and 300 kV underground substations became realized. This new technology was highly significant because it allowed large amounts of electric power to be efficiently supplied to urban areas where the installation of power sources is difficult. Initially, the rated breaking current was 50 kA, and it was increased to 63 kA. The hybrid puffer arc-extinguishing system is a key factor in this achievement. Hybrid puffer is Toshiba's original current breaking technology that utilizes the thermal energy of the arc during current interruption. 550 kV GCB with 2 breaks was developed, due to applying the technology of the 300 kV single-break GCB to 500 kV GCB with 4 breaks, In 1984, the first such system was delivered to the Buzen Substation of Kyushu Electric Power Company. This circuit breaker, which was utilized in a GIS, coupled with the technological innovations that had taken place in GIS systems such as the three-phase in common enclosure type main busbar, greatly contributed to the downsizing of the 550 kV GIS. A short-circuit current capacity of 63 kA and rated current of 8,000 A were also realized in response to the increase in system capacity.
In creating a 550 kV circuit breaker of the single-break type, further improvement of the breaking performance became necessary. Therefore, in addition to the hybrid puffer technology, we developed a dual-motion operation system. A conventional circuit breaker has a fixed contact and a movable contact, and only the movable contact is actuated. In contrast, the dual-motion configuration drives the movable contact in the usual way, while simultaneously driving another side contact in the opposite direction with one operating mechanism. This revolutionary technology greatly enhanced the relative operating speed of the contacts and played a major role in the realization of 550 kV single-break GCB. Toshiba's foresight in developing the dual-motion operation system is substantiated by the fact that other companies have been increasingly incorporating it into their systems in recent years.
We delivered the world's first 550 kV single-break GCB to the Shin-Tsukuba Substation of Tokyo Electric Power Company in 1993. 550 kV single-break GCBs were also incorporated into a GIS system, and has helped to achieve considerable reduction of required site area. In 1998, GIS of this type was supplied to the Shin-Toyosu Substation of Tokyo Electric Power Company, realizing the first 550 kV underground substation in the world. This substation has been attracting a great deal of attention, and even today many Japanese and overseas specialists make visits to study it.
World's First Large-Capacity Gas-Insulated Transformer
275 kV-300 MVA large-capacity nonflammable transformers with high-pressure SF6 gas used for both insulating and cooling medium, have been completed.
In 1967, Toshiba delivered nonflammable 66 kV-3,000 kVA transformers, using sulfur hexafluoride (SF6) gas instead of insulating oil for the first time in Japan, to the underground substation facility of The Dai-ichi Mutual Life Insurance Company (currently The Dai-ichi Life Insurance Co., Ltd.). The use of SF6 gas as an insulating medium started to spread widely and rapidly in the field of switchgears due to its high insulating performance and its advantage of nonflammability. In the case of transformers, however, use of SF6 did not expand like switchgears because of the quite weak cooling capability. As the result, the application of SF6 for transformers was limited within small transformers only. On the other hand, needs of large capacity gas insulated transformers for underground substations in urban area were getting higher and higher considering its excellent safety features. So the development of a largecapacity gas-insulated transformers (Large GIT) was a focus of expectations.
Early in 1980s, the development of large-capacity nonflammable transformers started in United States with the capacity around 300 MVA. But this plan was cancelled due to fiscal tightening by the U.S. government. In Japan, inspired by the plan above, the development of Large GIT has started in 1983. At that time, SF6 gas was believed to have insufficient cooling capacity by itself to realize Large GIT, so the concept of using fluorocarbon liquid as cooling medium was examined. Toshiba started its development with “Separate Cooling Structure”, applying independent metal cooling panels with fluorocarbon liquid between layers of sheet type winding insulated by PET film, which was originally tried by GE once. Transformer manufactures in Japan, each worked on development of Large GIT with its own invented structure and mechanism.
In 1989, Toshiba has completed its development as the world’ first Large GIT, with ratings of 154 kV-200 MVA, for the Asahi Substation of Tokyo Electric Power Company (TEPCO). Then, in 1990, Toshiba has expanded the application to the rating of 275 kV-300 MVA for TEPCO’s Shin-Sakado Substation.
Although Toshiba has realized Large GIT, the special structure with the built-in cooling panel to cool the coils, and the application of very expensive fluorocarbon liquid, raised the cost of Large GIT three times higher than that of the conventional oil type transformers. Considering commercial base continuity, Toshiba started further development of direct cooling with SF6 gas itself. In order to increase the cooling capacity, a development team was formed in Toshiba’s own Laboratory, and they started the research on measures to improve the cooling properties of the gas, the flow of gas inside the transformer coils, and the new structure to change the flow deviation of gas. These efforts resulted in a number of achievements and have reached the completion of 275 kV-300 MVA Large GIT with only SF6 as insulating and cooling medium in 1994 for TEPCO’s Higashi-Shinjuku Substation. It has realized with combination of technologies such as the boosting of gas pressure, the adoption of a highly heat-resistant insulating material that allowed the operation temperature higher, the development of a large-capacity high-pressure gas blower, and equalization of the temperature of the coil through detailed analysis of gas flow control in the coil. The rating of Large GIT developed here is one of our standard models and have been on sales since that time.
In the same year, Toshiba also commercialized 275 kV-150 MVA gas-insulated shunt reactors and delivered it to TEPCO’s Katsunan Substation. This marked a new era of gas-insulated transformers and shunt reactors that did not require a special system for cooling. As the result, Toshiba has realized “Oil-less substation” with gas-insulated equipment of this type and it has been replacing the oil type underground substation equipment as the mainstream of TEPCO’s underground substations. These gas-insulated systems have been adopted by other electric power companies in Japan as well, and also started to be applied in other countries, such as Australia, England, Russia, United States and Canada, as a key component for the safe and reliable underground substations in urban areas.
World's First Facsimile with a Cleanerless Process
Toshiba developed the ultimate electrophotographic technology used for copiers, facsimiles, etc., allowing more compact, maintenance-free laser printers to be realized that produced higher image quality.
Conventional electrophotography used a developer consisting of two particle components: toner particles and magnetic carrier particles. These were subjected to a process called triboelectrification in which the toner particles were electrified with a specified polarity. The particles were then conveyed to a photoreceptor drum by a magnetic roller. An electrostatic latent image was formed on the photoreceptor drum by image exposure. This image was visualized by the development process and transferred to paper. The toner particles remaining on the photoreceptor drum that had not been transferred to paper were removed by a cleaning blade and collected in a waste toner box. This gave rise to the need for periodical maintenance, which was an issue for this type of system. Moreover, the surfaces of the carrier particles were degraded by a coating of fine powder, etc. that was generated when they were churned together with the toner particles, so it was also necessary to periodically replace the carrier. On top of that, the carrier was held in place on the magnetic roller by magnetic force, and removing the carrier and toner particles from the roller was difficult work. We therefore focused our efforts on creating a developer consisting of a single component, with the aim of giving birth to a new technology that would eliminate these tasks and realize a maintenance-free system. Initially, we attempted to make a single-component magnetic toner that incorporated the carrier's function of conveyance by magnetic force into the function of the toner particles. However, due to the fact that the magnetic roller was necessary to carry the magnetic toner, miniaturization was difficult. We also judged that colorization would be problematic, and therefore abandoned that approach. Subsequently, we began to feel confident that a singlecomponent nonmagnetic toner was the best approach, and started development. Three difficult obstacles had to be overcome in order to realize such a system. The first was how to subject the toner particles to triboelectrification without the use of a carrier. The second was how to convey the nonmagnetic toner particles to the photoreceptor drum without magnetic force. And the third was how to reliably deposit the toner particles onto the charge distribution of the latent image in order to obtain high-quality images.
The first issue was solved by a design in which the toner particles were fed between the developing roller and an elastic blade. By optimizing the relations among the surface friction coefficients of the developing roller, the elastic blade and the toner, a thin monolayer of the toner on the rotating roller passed through under the blade. At the same time, a predetermined charge was given to the toner particles by triboelectric charging between the toner particles and the roller. Once a thin layer of charged toner particle was formed, it adhered to the roller by electrostatic force between the toner charge and the opposite charge which was induced on the conductive roller surface. As a result, toner particles were carried toward the photoreceptor drum without magnetic force, and the second issue was solved. As regards the third issue, we initially selected a noncontact developing method in which the toner was conveyed between the developing roller and the photoreceptor drum in a contact-free manner, and proceeded toward commercialization. Unfortunately, however, we had to abandon this method due to a problem with stability as well as an issue related to another company's patent, so we ultimately selected a contact type developing method. The development of an elastic developing roller using conductive rubber with specified triboelectrification and electrical resistivity properties was the key to success here.
We also found that the electric field enhancement effect produced by this newly developed contact type singlecomponent nonmagnetic developing method not only achieved developing with high image quality, but also a function of cleaning by the electric field used for developing. In 1995, after more than 10 years since the start of development work, we were able to commercialize a multifunctional laser facsimile.
World's First DVD Player
Toshiba acts as the leader of DVD standardization.
The “fire tower” turns into a slim DVD player.
In November 1996, Toshiba introduced the world's first DVD player, the SD-3000, as a result of developments initiated in 1994. At the time, the VHS VCR was dominating the market. Although high-quality laser disks had seen some success for Karaoke use, the disk size of 30 cm in diameter for a single movie was too large. Further, the laser disk used analog video.
The DVD (called SD at the time) produced by Toshiba used digital audio and video could fit an entire movie on a disk the same size as a CD: 12 cm in diameter. This was a revolutionary standard that made possible high audio and video quality and multiple functions. In order to record long video such as that of a movie on a single 12-centimeter disk, it was necessary to make the disks themselves high in density and to use technology to compress the video (MPEG2).
Fortunately, MPEG2 encoders for broadcasting applications had been developed, and Toshiba entered a partnership with Hollywood's Time-Warner in order to ensure a supply of content. Seeking to reduce the data size so that it would fit onto a single disk, while ensuring a level of quality that was acceptable to the professionals from Hollywood, repeated MPEG2 testing was conducted.
Two more requirements from Hollywood were that the price of disks be US $20 or less per title and that each side of a disk be capable of storing 135 minutes of video, in order to cover 90% of the films produced in Hollywood. In order to realize these goals, Toshiba proposed combining two 0.6 mm-thick high density disks to produce one 1.2 mm-thick disk (the same thickness as that of a CD).
In order to verify this unique method, trial player units were produced quickly. At the same time, trial production of disks began in cooperation with Warner Music of the US and Toshiba EMI (what is today EMI Music Japan Inc.). The trial player was called “fire tower” which included a great number of printed circuit boards in layers. Although it did not always operate with stability, it had a major impact on movie studios, computer companies, and the media worldwide, due to its extremely high picture quality and Dolby 5.1-channel Surround Sound. It was demonstrated to members of related industries in Japan with Toshiba strongly encouraging all companies to work together to promote a single DVD standard.
Toshiba's DVD standardization obtained a consensus among the industry and was promoted strongly. Later, Toshiba took the lead in combining the additional ideas of other companies into the DVD format and introduced the first slim DVD player, the SD-3000.
In 2004, terrestrial digital broadcasting was introduced, in addition to previously existing satellite digital broadcasting. Toshiba proposed the new AOD (advanced optical disk) format as a new optical disk medium for the high-definition television system era. It obtained the approval of the DVD Forum and began proceeding with development of this new technology.
Completion of the first Advanced Boiling Water Reactor
Development and construction of ABWR facilities brings together the essence of the latest technologies.
ABWRs will be the mainstay light water reactors in the 21st century.
In 1975, an industry-wide framework was established for an advanced boiling water reactor (ABWR). Under this framework, Toshiba cooperated with power companies to investigate the feasibility of a Reactor Internal Pump (RIP), a major component of the ABWR, contributing to the successful start of an ABWR development project.
In 1978, an international collaborative team, which consisted of the world BWR manufactures including General Electric (GE), Hitachi and Toshiba, began conceptual designs of the ABWR. Additionally, Toshiba participated in government-sponsored studies and a number of joint research projects with power companies to complete development testing and baseline design.
Consequently, the first ABWRs were adopted in Tokyo Electric Power Company's as Kashiwazaki-Kariwa Nuclear Power Plants Unit 6 and 7.
Toshiba represented the international joint venture, which consisted of GE, Hitachi and Toshiba, to put together the construction project for Unit 6, the first ABWR plant.
Unit 6 and 7 entered commercial operation in November 1996 and July 1997, respectively.
Since then, Toshiba has constructed several ABWR plants in Japan and is highly acclaimed by power companies around the world. In the United States, the ABWR plant design has obtained a standard design certification (SDC) from the U.S. Nuclear Regulatory Commission (NRC).
Toshiba's major technological contributions to the development of ABWR include the following;
To simplify piping interfaces for improved safety, reactor internal pumps (RIP) for control of core flow are directly mounted inside the reactor pressure vessel. The RIPs make it possible to do away with the external recirculation loop and jet pumps in former BWR plants. This eliminates the possibility of external pipe ruptures, enhancing the safety of a nuclear reactor and thus making it possible to reduce the capacity required for the emergency core cooling system (ECCS).
To reduce the per-kWh electricity cost, the ABWR is designed to provide larger power capacity and improved thermal efficiency. Therefore the ABWR has a rated output of about 1,350MW. To produce a large amount of power with higher efficiency, the ABWR uses a highefficiency turbine with 52-inch blades and a reheating cycle.
The fine motion control rod drive (FMCRD) is used to control the output of a nuclear power reactor. It slowly adjusts the positions of control rods using electric motors under normal conditions, while allowing for fast control rod adjustment using a hydraulic-driven system in the event of emergencies. The FMCRD controls the positions of multiple control rods simultaneously to shorten start-up time and is equipped with diverse drive source to improve reliability.
The ABWR uses a reinforced-concrete containment vessel (RCCV) integrated with a reactor building. This enhances economic efficiency by reducing the amount of steel materials and improving their structural utilization. It also helps to shorten the construction period because it allows simultaneous construction of the reactor building and RCCV. Additionally, the ABWR ensures higher seismic resistance by lowering the centers of gravity of the pressure vessel, RCCV and reactor building.
The ABWR fully utilizes state-of-the-art digital control systems such as digital instrumentation and control systems and optical multiplexing communication systems. The comprehensive digital control systems interconnected the main control panels and on-site equipment through an optical network to provide enhanced capabilities for efficient and safe operation of the plant.
Toshiba will continue to employ leading-edge technologies to further improve ABWRs so as to realize nuclear power plants with excellent safety, reliability, economic efficiency, operability, and maintainability.
Commercialization of World's First Hard Disk Drive Equipped with GMR Head
The recording density and capacity of hard disk drives were dramatically improved by innovative GMR head and perpendicular magnetic recording technologies.
To improve the recording density of a hard disk drive (HDD), a high-sensitivity head to read the weak magnetic field of the tiny recording bits is essential. The realization of a large rate of change in the magnetoresistance effect (referred to as the MR ratio) by a magnetic field is also important. In 1988, a major increase in the rate of change in resistance was achieved in Europe using an artificial lattice with alternately laminated layers of ultra-thin iron and chromium, which attracted considerable attention.
Toshiba responded to this situation by assembling a task force of personnel who had been working on video recorder heads and other devices, with the objective of developing a magnetic head, and in 1992 started research and development of a giant magnetoresistive (GMR) head. Rather than simply competing to attain a higher MR ratio, we focused our efforts on a spin valve configuration with two magnetic layers. The MR ratio was slightly smaller compared with that of a multilayer structure, but a good linear response was obtained that was suitable for detection of the reproduced signal. We then consolidated the basic design using an iridium-manganese (IrMn) alloy as a special magnetic layer with a magnetization fixed specifically for the spin valve configuration, and a cobalt-iron (CoFe) alloy that made it possible to control the crystal orientation so that a large MR ratio was produced even in a weak magnetic field.
Next we entered the phase of verifying a prototype of the head. The facilities available at the time were insufficient for this purpose, but with the understanding of management we introduced expensive equipment such as a stepper and accelerated the development work. As a result, at the end of 1997 we were able to issue a press release announcing the world's first practical HDD equipped with a GMR head, offering a recording density of 3 Gbit/in2. After that, HDDs began to be installed not only in PCs but also many other products such as portable music players, DVD players, and so on.
Concurrently with this development work, we also initiated research on perpendicular recording using a medium with perpendicular magnetic anisotropy that was made of cobaltchromium (CoCr)-based metallic magnetic material, aiming at the achievement of higher recording density. Although perpendicular recording was considered to be a superior technology in theoretical terms, at that stage nobody had been able to demonstrate its ability to provide performance significantly exceeding that of conventional longitudinal recording. A turning point came when a certain physical phenomenon, in which recording magnetization is attenuated by thermal fluctuations, became more conspicuous in longitudinal recording. In the case of perpendicular recording, on the other hand, it was understood that the higher the density, the greater the intensification of the adjacent magnetization. Moreover, the volume of magnetic particles could be increased. This meant that perpendicular recording would have a very high tolerance of thermal fluctuations.
Around 1994, we were working on the development of cobaltplatinum oxide (CoPtO)-based magnetic materials with high magnetic anisotropy, aiming at the realization of a longitudinal recording medium with a high tolerance of thermal fluctuations, when this development work had an unexpected outcome. The magnetic particle structure that we were investigating, in which CoPt crystal with high magnetic anisotropy served as a core surrounded by an amorphous layer with a high concentration of oxygen, was a unique configuration developed by our company. We embarked on the introduction of oxygen, which was considered to be taboo for metal films because of the fear of oxidation, but, as an outcome of this, were able to realize the ideal characteristics for perpendicular magnetization. The amorphous grain boundary containing a high oxygen concentration maintained the exchange coupling between the grains, and the material was found to have an excellent ability to maintain its magnetic characteristics from low to high temperatures.
In 1997, while engaged in a study to enhance the performance of magnetic film, we also found that ruthenium (Ru) was an excellent base material for crystal growth control. Through the combination of these discoveries—namely, the CoPtO-based magnetic material, grain boundary separation by an oxide, and the use of Ru as the base material for crystal growth—the design concept of the magnetic characteristics and recording material of the perpendicular recording medium became clear and the research and development work rapidly progressed. At a technological exhibition held at the Ome Works (currently the Ome Complex) in January 2002, a PC equipped with a perpendicular recording HDD was shown to the press for the first time in the world, and received an enthusiastic response. In 2005, we shipped the world's first perpendicular recording HDD products. These products had a recording density of 133 Gbit/in2, the highest HDD recording density in the world, as well as excellent environmental robustness. They led the way in a major shift in the field of recording systems, the first such shift to have occurred in the history of magnetic recording.
Practical Application of World's First Voice Synthesis System with High-Quality Sound
From the concept of voice coding, we developed a closed-loop learning method that automatically learned from voice data for the first time in the world and completed the world’s preeminent voice synthesis method.
Research on voice synthesis started with the aim of realizing a human interface technology for interaction with computers, similar to voice recognition. In 1982, we developed a voice word processor that converted voiced syllables into written characters, and applied it to a voice recognition response system for banks. After that, in addition to improving the method itself, we developed dedicated hardware as well as voice synthesis software running on a workstation and, in 1995, commercialized a voice synthesis software that operated on a PC. However, the sound quality and naturalness of the synthesized voice was not at all satisfactory, and it was described as a “nasal voice” or “robot voice.” The sound quality of the synthesized voice could have been improved by expanding the speech segment dictionary for waveform generation. However, this would have increased the size of the dictionary to the point where it would be difficult to implement the system on small-scale hardware. There was also the issue of the long time required for development, because the creation of a speech segment dictionary relies on a process of trial and error by technical specialists. Various approaches to solve these issues were investigated by a number of research institutions, but no decisive solution appeared.
This situation completely changed in 1994 with the participation of a voice coding researcher in our research efforts. The issues were reinvestigated from zero, free from the common perceptions of voice synthesis. Rather than basing our approach on existing knowledge or knowhow, we decided to focus on automatic learning of voice synthesis parameters from voice data as the fundamental policy. Finally, based on analysis of the causes of the nasal and robotic-sounding voices, we succeeded in formularizing the issue of sound quality in the form of errors from the learning data.
Next, we developed a closed-loop learning method for the speech segment dictionary that minimized errors in the synthesized sound based on this formularization, the first time in the world such a system had been actualized. This memory-efficient system solved the contradiction between sound quality and dictionary size, maximizing the quality of the sound while using a minimum of speech segments and providing high-quality, natural synthesized sound similar to the human voice. Another feature of the system was that, once the learning data had been prepared, a synthesis dictionary could be automatically created in a short period of time to produce synthesized sound close to the human voices used for the learning data. This closed-loop learning method was a revolutionary system that broke through the conventional belief up to that time that the development of a voice synthesis system inevitably required knowledge and knowhow accumulated over many years as well as a process of trial and error relying on the ears of technical specialists. In order to achieve the practical application of these research results, the researchers themselves visited customers and cultivated the market. In 1998, our voice synthesis middleware was adopted by a leading automobile manufacturer. Other manufacturers followed suit, and by 2006 it held a 94% share in the domestic car navigation market. In 2002, we established research and development bases in the U.K. and China and worked on the preparation of multilingual versions. Today, Toshiba’s voice synthesis and voice recognition technologies have been adopted in the European and American markets as well as the Chinese market. We are also pioneering new services such as the application of voice synthesis to the creation of contents, and are promoting the development of speaker adaptation and speaking characteristics adaptation technologies that can synthesize the voices of specific speakers and ways of speaking, as well as an emotional voice synthesis technology that can synthesize emotional voices. In these ways we are making efforts to expand the fields of application of our system.
World's First Variable-Cylinder Dual-Rotary Compressor
Fully utilizing precision processing technology, Toshiba was the first company in Japan to independently develop such compressors, leading the world in inverter technology and establishing the trend of compressors for air-conditioners.
General Electric Company (GE) in the U.S. commercialized a rotary compressor for air-conditioners in the early 1950s. In Japan, our company independently proceeded with the development of a rotary compressor for air-conditioners from 1967 onward, using GE's model 30 series as a reference. This development work became a company-wide project and finally, in 1969, we developed Japan's first rotary compressor for air-conditioners using our own technology. By the development of made high-speed and high precision processing on the order of micrometers, rotary compressors got high efficiency, structural simplicity, and low cost. Today, rotary compressors have been adopted in innumerable residential air conditioners throughout the world, and it would be no exaggeration to say that our company played the leading role in the history of rotary compressors.
Subsequently, accompanying the increased awareness of energy saving due to the oil crisis in 1973, variable speed compressors, which can control capacity, were needed with a function allowing variable capacity control instead of the conventional type in which the room temperature was controlled only by on/off operation. At that time, compressors, can not be operated such a wide range of rotation speeds from low to high, and equipping an inverter with an air conditioner was considered to be difficult due to high cost and bulky dimensions.
Once again, however, we overcame the obstacles and developed an AC inverter-driven single-rotary compressor for residential air-conditioners that was capable of handling variable speeds. By reduction in the size and weight of the inverter, we released the world's first inverter type rotary air conditioner for home use in 1981. This attracted a tremendous response, and in recognition of the revolutionary role of this product in the history of airconditioner technology, Toshiba received the 16th Contribution Prize of the Ichimura Industrial Awards from the New Technology Development Foundation in 1984. We then went on to develop an AC inverter-driven twinrotary compressor for home use in 1988. The twin-rotary compressor not only made it possible to significantly improve cooling and heating capacity, but also achieved lower vibration and quieter operation. Next we developed a DC inverter-driven twin-rotary compressor in 1993, which achieved such a high level of energy saving that the electricity bill was halved compared with conventional models. This development was made possible by driving the compressor with a newly developed DC motor instead of the AC motor used up to that time. Then, in 2004, we developed the world's first variable-cylinder dual-rotary compressor, which realized super energy saving. For this achievement, Toshiba was awarded the 2nd New JSPMI Prize by the Japan Society for the Promotion of Machine Industry in 2005.
In order to maintain a constant temperature in steady operation, the conventional twin-rotary compressors still wasted electricity by on and off operation, even with inverter control. The introduction of a dual variable-cylinder configuration can be allowed steady operation with only one cylinder off to maintain a constant temperature, realizing the ultimate super-energy-saving operation. The energy-saving effect is particularly conspicuous in presentday detached houses, condominiums, and offices, which have a highly airtight structure. Our high-efficiency variable-cylinder rotary compressor has continued to evolve, and was awarded the JSME Medal for New Technology by the Japan Society of Mechanical Engineers in 2012.