tft display technology pdf quotation

A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technologyactive matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven (i.e. with segments directly connected to electronics outside the LCD) LCDs with a few segments.

In February 1957, John Wallmark of RCA filed a patent for a thin film MOSFET. Paul K. Weimer, also of RCA implemented Wallmark"s ideas and developed the thin-film transistor (TFT) in 1962, a type of MOSFET distinct from the standard bulk MOSFET. It was made with thin films of cadmium selenide and cadmium sulfide. The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968. In 1971, Lechner, F. J. Marlowe, E. O. Nester and J. Tults demonstrated a 2-by-18 matrix display driven by a hybrid circuit using the dynamic scattering mode of LCDs.T. Peter Brody, J. A. Asars and G. D. Dixon at Westinghouse Research Laboratories developed a CdSe (cadmium selenide) TFT, which they used to demonstrate the first CdSe thin-film-transistor liquid-crystal display (TFT LCD).active-matrix liquid-crystal display (AM LCD) using CdSe TFTs in 1974, and then Brody coined the term "active matrix" in 1975.high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.

The liquid crystal displays used in calculators and other devices with similarly simple displays have direct-driven image elements, and therefore a voltage can be easily applied across just one segment of these types of displays without interfering with the other segments. This would be impractical for a large display, because it would have a large number of (color) picture elements (pixels), and thus it would require millions of connections, both top and bottom for each one of the three colors (red, green and blue) of every pixel. To avoid this issue, the pixels are addressed in rows and columns, reducing the connection count from millions down to thousands. The column and row wires attach to transistor switches, one for each pixel. The one-way current passing characteristic of the transistor prevents the charge that is being applied to each pixel from being drained between refreshes to a display"s image. Each pixel is a small capacitor with a layer of insulating liquid crystal sandwiched between transparent conductive ITO layers.

The circuit layout process of a TFT-LCD is very similar to that of semiconductor products. However, rather than fabricating the transistors from silicon, that is formed into a crystalline silicon wafer, they are made from a thin film of amorphous silicon that is deposited on a glass panel. The silicon layer for TFT-LCDs is typically deposited using the PECVD process.

Polycrystalline silicon is sometimes used in displays requiring higher TFT performance. Examples include small high-resolution displays such as those found in projectors or viewfinders. Amorphous silicon-based TFTs are by far the most common, due to their lower production cost, whereas polycrystalline silicon TFTs are more costly and much more difficult to produce.

The twisted nematic display is one of the oldest and frequently cheapest kind of LCD display technologies available. TN displays benefit from fast pixel response times and less smearing than other LCD display technology, but suffer from poor color reproduction and limited viewing angles, especially in the vertical direction. Colors will shift, potentially to the point of completely inverting, when viewed at an angle that is not perpendicular to the display. Modern, high end consumer products have developed methods to overcome the technology"s shortcomings, such as RTC (Response Time Compensation / Overdrive) technologies. Modern TN displays can look significantly better than older TN displays from decades earlier, but overall TN has inferior viewing angles and poor color in comparison to other technology.

Most TN panels can represent colors using only six bits per RGB channel, or 18 bit in total, and are unable to display the 16.7 million color shades (24-bit truecolor) that are available using 24-bit color. Instead, these panels display interpolated 24-bit color using a dithering method that combines adjacent pixels to simulate the desired shade. They can also use a form of temporal dithering called Frame Rate Control (FRC), which cycles between different shades with each new frame to simulate an intermediate shade. Such 18 bit panels with dithering are sometimes advertised as having "16.2 million colors". These color simulation methods are noticeable to many people and highly bothersome to some.gamut (often referred to as a percentage of the NTSC 1953 color gamut) are also due to backlighting technology. It is not uncommon for older displays to range from 10% to 26% of the NTSC color gamut, whereas other kind of displays, utilizing more complicated CCFL or LED phosphor formulations or RGB LED backlights, may extend past 100% of the NTSC color gamut, a difference quite perceivable by the human eye.

Initial iterations of IPS technology were characterised by slow response time and a low contrast ratio but later revisions have made marked improvements to these shortcomings. Because of its wide viewing angle and accurate color reproduction (with almost no off-angle color shift), IPS is widely employed in high-end monitors aimed at professional graphic artists, although with the recent fall in price it has been seen in the mainstream market as well. IPS technology was sold to Panasonic by Hitachi.

IPS has since been superseded by S-IPS (Super-IPS, Hitachi Ltd. in 1998), which has all the benefits of IPS technology with the addition of improved pixel refresh timing.

In 2004, Hydis Technologies Co., Ltd licensed its AFFS patent to Japan"s Hitachi Displays. Hitachi is using AFFS to manufacture high end panels in their product line. In 2006, Hydis also licensed its AFFS to Sanyo Epson Imaging Devices Corporation.

A technology developed by Samsung is Super PLS, which bears similarities to IPS panels, has wider viewing angles, better image quality, increased brightness, and lower production costs. PLS technology debuted in the PC display market with the release of the Samsung S27A850 and S24A850 monitors in September 2011.

TFT dual-transistor pixel or cell technology is a reflective-display technology for use in very-low-power-consumption applications such as electronic shelf labels (ESL), digital watches, or metering. DTP involves adding a secondary transistor gate in the single TFT cell to maintain the display of a pixel during a period of 1s without loss of image or without degrading the TFT transistors over time. By slowing the refresh rate of the standard frequency from 60 Hz to 1 Hz, DTP claims to increase the power efficiency by multiple orders of magnitude.

Due to the very high cost of building TFT factories, there are few major OEM panel vendors for large display panels. The glass panel suppliers are as follows:

External consumer display devices like a TFT LCD feature one or more analog VGA, DVI, HDMI, or DisplayPort interface, with many featuring a selection of these interfaces. Inside external display devices there is a controller board that will convert the video signal using color mapping and image scaling usually employing the discrete cosine transform (DCT) in order to convert any video source like CVBS, VGA, DVI, HDMI, etc. into digital RGB at the native resolution of the display panel. In a laptop the graphics chip will directly produce a signal suitable for connection to the built-in TFT display. A control mechanism for the backlight is usually included on the same controller board.

The low level interface of STN, DSTN, or TFT display panels use either single ended TTL 5 V signal for older displays or TTL 3.3 V for slightly newer displays that transmits the pixel clock, horizontal sync, vertical sync, digital red, digital green, digital blue in parallel. Some models (for example the AT070TN92) also feature input/display enable, horizontal scan direction and vertical scan direction signals.

New and large (>15") TFT displays often use LVDS signaling that transmits the same contents as the parallel interface (Hsync, Vsync, RGB) but will put control and RGB bits into a number of serial transmission lines synchronized to a clock whose rate is equal to the pixel rate. LVDS transmits seven bits per clock per data line, with six bits being data and one bit used to signal if the other six bits need to be inverted in order to maintain DC balance. Low-cost TFT displays often have three data lines and therefore only directly support 18 bits per pixel. Upscale displays have four or five data lines to support 24 bits per pixel (truecolor) or 30 bits per pixel respectively. Panel manufacturers are slowly replacing LVDS with Internal DisplayPort and Embedded DisplayPort, which allow sixfold reduction of the number of differential pairs.

The bare display panel will only accept a digital video signal at the resolution determined by the panel pixel matrix designed at manufacture. Some screen panels will ignore the LSB bits of the color information to present a consistent interface (8 bit -> 6 bit/color x3).

With analogue signals like VGA, the display controller also needs to perform a high speed analog to digital conversion. With digital input signals like DVI or HDMI some simple reordering of the bits is needed before feeding it to the rescaler if the input resolution doesn"t match the display panel resolution.

Kawamoto, H. (2012). "The Inventors of TFT Active-Matrix LCD Receive the 2011 IEEE Nishizawa Medal". Journal of Display Technology. 8 (1): 3–4. Bibcode:2012JDisT...8....3K. doi:10.1109/JDT.2011.2177740. ISSN 1551-319X.

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K. H. Lee; H. Y. Kim; K. H. Park; S. J. Jang; I. C. Park & J. Y. Lee (June 2006). "A Novel Outdoor Readability of Portable TFT-LCD with AFFS Technology". SID Symposium Digest of Technical Papers. AIP. 37 (1): 1079–82. doi:10.1889/1.2433159. S2CID 129569963.

Kim, Sae-Bom; Kim, Woong-Ki; Chounlamany, Vanseng; Seo, Jaehwan; Yoo, Jisu; Jo, Hun-Je; Jung, Jinho (15 August 2012). "Identification of multi-level toxicity of liquid crystal display wastewater toward Daphnia magna and Moina macrocopa". Journal of Hazardous Materials. Seoul, Korea; Laos, Lao. 227–228: 327–333. doi:10.1016/j.jhazmat.2012.05.059. PMID 22677053.

The integration of active matrix polysilicon TFT technology with organic light emitting diode (OLED) displays has been investigated with the goal of producing displays of uniform brightness. This work identifies and addresses several process integration issues unique to this type of display which are important in achieving bright and uniform displays. Rapid thermal processing has been incorporated to achieve uniform polysilicon microstructure, along with silicides to reduce parasitic source and drain series resistance. Using these processes, TFT drain current nonuniformity has been reduced below 5% for 90% of the devices. This work also introduces transition metals to produce low resistance contacts to ITO and to eliminate hillock formation in the aluminum metallization. These processes, along with spin on glasses for planarization, have been used to produce functional active matrix arrays for OLED displays. The final array pixel performance is also presented.

A dynamic analysis of an amorphous silicon (a-Si) Thin-Film-Transistor-Liquid-Crystal-Display (TFT-LCD) pixel is presented using new a-Si TFT model and new Liquid Crystal (LC) capacitance models for SPICE simulators. This analysis is useful to all Active Matrix LCD designers for evaluating and predicting the performance of LCD"s. The a-Si TFT model is developed to simulate important a-Si TFT characteristics such as off-leakage current, threshold voltage shift due to voltage stress and…Expand

An LCD (Liquid Crystal Display) is a standard display device for hand-held embedded systems. Today, color TFT (Thin-Film Transistor) LCDs are common even in cost-effective equipments. An LCD display system is composed of an LCD panel, a frame buffer memory, an LCD and frame buffer controller, and a backlight inverter and lamp. All of them are heavy power consumers, and their portion becomes much more dominant when running interactive applications. This is because interactive applications are…Expand

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IPS, also known as In-Plane Switching, is a type of monitor display and screen technology that uses a voltage to control the alignment of liquid crystals, similar to TN technology. However, IPS displays use a different crystal orientation where the crystals are parallel to the glass substrates, hence the term ‘in-plane’. Rather than ‘twisting’ the crystals to modify the amount of light let through, IPS crystals are essentially rotated, which has a range of benefits. IPS displays offer the best color reproduction as well as the widest viewing angles compared to other LCD technologies.

While TN LCD’s support high refresh rates with low response times, they do come with sub-optimal viewing angles, and slightly diminished color reproduction. IPS panels address these downfalls with 80 degree viewing angles that eliminate color inversion and contrast diminishment. IPS technology is ideal for a wide array of applications such as medical, industrial, HVAC, Pool/Spa due to the ability to use the displays in both landscape and portrait mode while maintaining uniform viewing angles. This also allows for displays to be seen from different angles and heights, ideal for jacuzzi controls and thermostats that tend to require consideration of dynamic user parameters.

In recent years, China and other countries have invested heavily in the research and manufacturing capacity of display technology. Meanwhile, different display technology scenarios, ranging from traditional LCD (liquid crystal display) to rapidly expanding OLED (organic light-emitting diode) and emerging QLED (quantum-dot light-emitting diode), are competing for market dominance. Amidst the trivium strife, OLED, backed by technology leader Apple"s decision to use OLED for its iPhone X, seems to have a better position, yet QLED, despite still having technological obstacles to overcome, has displayed potential advantage in color quality, lower production costs and longer life.

Which technology will win the heated competition? How have Chinese manufacturers and research institutes been prepared for display technology development? What policies should be enacted to encourage China"s innovation and promote its international competitiveness? At an online forum organized by National Science Review, its associate editor-in-chief, Dongyuan Zhao, asked four leading experts and scientists in China.

Zhao: We all know display technologies are very important. Currently, there are OLED, QLED and traditional LCD technologies competing with each other. What are their differences and specific advantages? Shall we start from OLED?

Huang: OLED has developed very quickly in recent years. It is better to compare it with traditional LCD if we want to have a clear understanding of its characteristics. In terms of structure, LCD largely consists of three parts: backlight, TFT backplane and cell, or liquid section for display. Different from LCD, OLED lights directly with electricity. Thus, it does not need backlight, but it still needs the TFT backplane to control where to light. Because it is free from backlight, OLED has a thinner body, higher response time, higher color contrast and lower power consumption. Potentially, it may even have a cost advantage over LCD. The biggest breakthrough is its flexible display, which seems very hard to achieve for LCD.

Liao: Actually, there were/are many different types of display technologies, such as CRT (cathode ray tube), PDP (plasma display panel), LCD, LCOS (liquid crystals on silicon), laser display, LED (light-emitting diodes), SED (surface-conduction electron-emitter display), FED (filed emission display), OLED, QLED and Micro LED. From display technology lifespan point of view, Micro LED and QLED may be considered as in the introduction phase, OLED is in the growth phase, LCD for both computer and TV is in the maturity phase, but LCD for cellphone is in the decline phase, PDP and CRT are in the elimination phase. Now, LCD products are still dominating the display market while OLED is penetrating the market. As just mentioned by Dr Huang, OLED indeed has some advantages over LCD.

Huang: Despite the apparent technological advantages of OLED over LCD, it is not straightforward for OLED to replace LCD. For example, although both OLED and LCD use the TFT backplane, the OLED’s TFT is much more difficult to be made than that of the voltage-driven LCD because OLED is current-driven. Generally speaking, problems for mass production of display technology can be divided into three categories, namely scientific problems, engineering problems and production problems. The ways and cycles to solve these three kinds of problems are different.

Liao: I want to supplement some data. According to the consulting firm HIS Markit, in 2018, the global market value for OLED products will be US$38.5 billion. But in 2020, it will reach US$67 billion, with an average compound annual growth rate of 46%. Another prediction estimates that OLED accounts for 33% of the display market sales, with the remaining 67% by LCD in 2018. But OLED’s market share could reach to 54% in 2020.

Huang: While different sources may have different prediction, the advantage of OLED over LCD in small and medium-sized display screen is clear. In small-sized screen, such as smart watch and smart phone, the penetration rate of OLED is roughly 20% to 30%, which represents certain competitiveness. For large size screen, such as TV, the advancement of OLED [against LCD] may need more time.

Xu: LCD was first proposed in 1968. During its development process, the technology has gradually overcome its own shortcomings and defeated other technologies. What are its remaining flaws? It is widely recognized that LCD is very hard to be made flexible. In addition, LCD does not emit light, so a back light is needed. The trend for display technologies is of course towards lighter and thinner (screen).

But currently, LCD is very mature and economic. It far surpasses OLED, and its picture quality and display contrast do not lag behind. Currently, LCD technology"s main target is head-mounted display (HMD), which means we must work on display resolution. In addition, OLED currently is only appropriate for medium and small-sized screens, but large screen has to rely on LCD. This is why the industry remains investing in the 10.5th generation production line (of LCD).

Xu: While deeply impacted by OLED’s super thin and flexible display, we also need to analyse the insufficiency of OLED. With lighting material being organic, its display life might be shorter. LCD can easily be used for 100 000 hours. The other defense effort by LCD is to develop flexible screen to counterattack the flexible display of OLED. But it is true that big worries exist in LCD industry.

Some experts working at a market survey institute CCID (China Center for Information Industry Development) predicted that in five to six years, OLED will be very influential in small and medium-sized screen. Similarly, a top executive of BOE Technology said that after five to six years, OLED will counterweigh or even surpass LCD in smaller sizes, but to catch up with LCD, it may need 10 to 15 years.

Xu: Besides LCD, Micro LED (Micro Light-Emitting Diode Display) has evolved for many years, though people"s real attention to the display option was not aroused until May 2014 when Apple acquired US-based Micro LED developer LuxVue Technology. It is expected that Micro LED will be used on wearable digital devices to improve battery"s life and screen brightness.

Micro LED, also called mLED or μLED, is a new display technology. Using a so-called mass transfer technology, Micro LED displays consist of arrays of microscopic LEDs forming the individual pixel elements. It can offer better contrast, response times, very high resolution and energy efficiency. Compared with OLED, it has higher lightening efficiency and longer life span, but its flexible display is inferior to OLED. Compared with LCD, Micro LED has better contrast, response times and energy efficiency. It is widely considered appropriate for wearables, AR/VR, auto display and mini-projector.

However, Micro LED still has some technological bottlenecks in epitaxy, mass transfer, driving circuit, full colorization, and monitoring and repairing. It also has a very high manufacturing cost. In short term, it cannot compete traditional LCD. But as a new generation of display technology after LCD and OLED, Micro LED has received wide attentions and it should enjoy fast commercialization in the coming three to five years.

Peng: It comes to quantum dot. First, QLED TV on market today is a misleading concept. Quantum dots are a class of semiconductor nanocrystals, whose emission wavelength can be continuously tuned because of the so-called quantum confinement effect. Because they are inorganic crystals, quantum dots in display devices are very stable. Also, due to their single crystalline nature, emission color of quantum dots can be extremely pure, which dictates the color quality of display devices.

Interestingly, quantum dots as light-emitting materials are related to both OLED and LCD. The so-called QLED TVs on market are actually quantum-dot enhanced LCD TVs, which use quantum dots to replace the green and red phosphors in LCD’s backlight unit. By doing so, LCD displays greatly improve their color purity, picture quality and potentially energy consumption. The working mechanisms of quantum dots in these enhanced LCD displays is their photoluminescence.

Another big difference between OLED and QLED is their production technology. OLED relies on a high-precision technique called vacuum evaporation with high-resolution mask. QLED cannot be produced in this way because quantum dots as inorganic nanocrystals are very difficult to be vaporized. If QLED is commercially produced, it has to be printed and processed with solution-based technology. You can consider this as a weakness, since the printing electronics at present is far less precision than the vacuum-based technology. However, solution-based processing can also be considered as an advantage, because if the production problem is overcome, it costs much less than the vacuum-based technology applied for OLED. Without considering TFT, investment into an OLED production line often costs tens of billions of yuan but investment for QLED could be just 90–95% less.

Given the relatively low resolution of printing technology, QLED shall be difficult to reach a resolution greater than 300 PPI (pixels per inch) within a few years. Thus, QLED might not be applied for small-sized displays at present and its potential will be medium to large-sized displays.

Peng: Good questions. Ligand chemistry of quantum dots has developed quickly in the past two to three years. Colloidal stability of inorganic nanocrystals should be said of being solved. We reported in 2016 that one gram of quantum dots can be stably dispersed in one milliliter of organic solution, which is certainly sufficient for printing technology. For the second question, several companies have been able to mass produce quantum dots. At present, all these production volume is built for fabrication of the backlighting units for LCD. It is believed that all high-end TVs from Samsung in 2017 are all LCD TVs with quantum-dot backlighting units. In addition, Nanosys in the United States is also producing quantum dots for LCD TVs. NajingTech at Hangzhou, China demonstrate production capacity to support the Chinese TV makers. To my knowledge, NajingTech is establishing a production line for 10 million sets of color TVs with quantum-dot backlighting units annually.China"s current demands cannot be fully satisfied from the foreign companies. It is also necessary to fulfill the demands of domestic market. That is why China must develop its OLED production capability.

Huang: Based on my understanding of Samsung, the leading Korean player in OLED market, we cannot say it had foresight in the very beginning. Samsung began to invest in AMOLED (active-matrix organic light-emitting diode, a major type of OLED used in the display industry) in about 2003, and did not realize mass production until 2007. Its OLED production reached profitability in 2010. Since then, Samsung gradually secured a market monopoly status.

So, originally, OLED was only one of Samsung"s several alternative technology pathways. But step by step, it achieved an advantageous status in the market and so tended to maintain it by expanding its production capacity.

Also, Samsung has spent considerable time and efforts on the development of the product chain. Twenty or thirty years ago, Japan owned the most complete product chain for display products. But since Samsung entered the field in that time, it has spent huge energies to cultivate upstream and downstream Korean firms. Now the Republic of Korea (ROK) manufacturers began to occupy a large share in the market.

Although we cannot say that our advantages triumph over ROK, where Samsung and LG have been dominating the field for many years, we have achieved many significant progresses in developing the material and parts of OLED. We also have high level of innovation in process technology and designs. We already have several major manufacturers, such as Visionox, BOE, EDO and Tianma, which have owned significant technological reserves.

Peng: As mentioned above, there are two ways to apply quantum dots for display, namely photoluminescence in backlightingFor QLED, the three stages of technological development [from science issue to engineering and finally to mass production] have been mingled together at the same time. If one wants to win the competition, it is necessary to invest on all three dimensions.

After I returned to China, NajingTech (co-founded by Peng) purchased all key patents invented by me in the United States under the permission of US government. These patents cover the basic synthesis and processing technologies of quantum dots. NajingTech has already established capability for large-scale production of quantum dots. Comparatively, Korea—represented by Samsung—is the current leading company in all aspects of display industry, which offers great advantages in commercialization of quantum-dot displays. In late 2016, Samsung acquired QD Vision (a leading quantum-dot technology developer based in the United States). In addition, Samsung has invested heavily in purchasing quantum-dot-related patents and in developing the technology.

China is internationally leading in electroluminescence at present. In fact, it was the 2014 Nature publication by a group of scientists from Zhejiang University that proved QLED can reach the stringent requirements for display applications. However, who will become the final winner of the international competition on electroluminescence remains unclear. China"s investment in quantum-dot technology lags far behind US and ROK. Basically, the quantum-dot research has been centered in US for most of its history, and South Korean players have invested heavily along this direction as well.

For electroluminescence, it is very likely to co-exist with OLED for a long period of time. This is so because, in small screen, QLED’s resolution is limited by printing technology.

Peng: If electroluminescence can be successfully achieved with printing, it will be much cheaper, with only about 1/10th cost of OLED. Manufacturers like NajingTech and BOE in China have demonstrated printing displays with quantum dots. At present, QLED does not compete with OLED directly, given its market in small-sized screen. A while ago, Dr. Huang mentioned three stages of technological development, from science issue to engineering and finally to mass production. For QLED, the three stages have been mingled together at the same time. If one wants to win the competition, it is necessary to invest on all three dimensions.

It seems to be possible that the flexible display will eventually lead a killer advantage. I think QLED will also face similar situation. What is its real advantage if it is compared with OLED or LCD? For QLED, it seems to have been difficult to find the advantage in small screen. Dr. Peng has suggested its advantage lies in medium-sized screen, but what is its uniqueness?

Peng: The two types of key advantages of QLED are discussed above. One, QLED is based on solution-based printing technology, which is low cost and high yield. Two, quantum-dot emitters vender QLED with a large color gamut, high picture quality and superior device lifetime. Medium-sized screen is easiest for the coming QLED technologies but QLED for large screen is probably a reasonable extension afterwards.

Huang: But customers may not accept only better wider color range if they need to pay more money for this. I would suggest QLED consider the changes in color standards, such as the newly released BT2020 (defining high-definition 4 K TV), and new unique applications which cannot be satisfied by other technologies. The future of QLED seems also relying on the maturity of printing technology.

Peng: New standard (BT2020) certainly helps QLED, given BT2020 meaning a broad color gamut. Among the technologies discussed today, quantum-dot displays in either form are the only ones that can satisfy BT2020 without any optical compensation. In addition, studies found that the picture quality of display is highly associated with color gamut. It is correct that the maturity of printing technology plays an important role in the development of QLED. The current printing technology is ready for medium-sized screen and should be able to be extended to large-sized screen without much trouble.

Xu: For QLED to become a dominant technology, it is still difficult. In its development process, OLED precedes it and there are other rivaling technologies following. While we know owning the foundational patents and core technologies of QLED can make you a good position, holding core technologies alone cannot ensure you to become a mainstream technology. The government"s investment in such key technologies after all is small as compared with industry and cannot decide QLED to become mainstream technology.

Liao: Due to their lack of kernel technologies, Chinese OLED panel manufacturers heavily rely on investments to improve their market competitiveness. But this may cause the overheated investment in the OLED industry. In recent years, China has already imported quite a few new OLED production lines with the total cost of about 450 billion yuan (US$71.5 billion).Lots of advantages of OLED over LCD were highlighted, such as high color gamut, high contrast and high response speed and so on …. It seems to be possible that the flexible display will eventually lead a killer advantage.

Zhao: Today there are really good observations, discussions and suggestions. The industry-academics-research collaboration is crucial to the future of China"s display technologies. We all should work hard on this.

Sharp demonstrated a fourteen-inch TFT-LCD for TV in 1988 when the display size of the mass-produced TFT-LCD was three inches. The high display quality in Cathode Ray Tube size convinced other electronic companies to join the infant TFT-LCD industry aimed at emerging full-color portable PCs. Two decades later, TFT-LCDs replaced CRTs, making the vision of RCA"s LCD group in the 1960s a reality.

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

The milestone plaque is to be kept in Sharp Technology Innovation Museum, and shown to the public along with other milestones of Sharp business activities of a 100 year history.

Sharp Technology Innovation Museum is located in the premise of Sharp Technology Center where LCD research was started and culminated in mass-producing the world-first mini-calculator mounted with LCD and C-MOS logic : the calculator is displayed at the British Science Museum.

It showed that an ideal display, namely, a flat, low-power, light-weight, CRT-sized full-color video display ,which could be used also in high ambient light, is technologically feasible, and that is exactly what had been long waited for to be used in an emerging information age since LCD was press-released in 1968 by RCA.

3. A large mother glass scheme could work for a-Si-TFT-LCD, which was proved by the high display uniformity across the entire display area. The mother glass 300mm x 320mm was the very forerunner of the mother glass generation competition which started around 1990, 2 years after Sharp 14-in. full color TFT-LCD was demonstrated.

At the time when a mere small 3-in. a-Si-TFT-LCD production was just started with poor yield, unstable and far-from-being-matured production equipment, small output capacity drivers, engineers had to prepare line-defect free TFT-LCD panels with high display quality, meaning large contrast ratio, high color saturation with high uniformity, and they made a precise electrical and physical system analysis and designing and devised redundant pixel and bus line schemes, and employed normally-white LCD operation mode, which was first employed in 3-in. TFT-LCD panel, and developed the TFT-LCD panel and its driving scheme to achieve higher contrast ratio, better gray scale and full-color rendition, wider tolerance in temperature and cell-gap variations, leading higher display uniformity across the entire large display area, than normally-black mode could achieve in those days.

Sharp"s first application of TFT-LCD was television which is supposed to be exposed to "critical" consumers 3-5 hours everyday for more than 10 years.

So, from the very beginning of development project started in April 1984, TV business group, who understand the market, located in Yaita-shi, Tochigi-ken, and TFT-LCD research group located in Tenri-shi, Nara-ken, worked closely; even though, two places are about 600km apart.

TV group, headed by Magohiro ARAMOTO, whose leading member was Masakazu YAMAMOTO, joined by Shuhji KOHZAI later on, showed the clear target specifications and pointed out critical display quality factors to be improved, and also transferred TV evaluation methods to TFT-LCD research group; TFT-LCD research group, headed by Masataka MATUURA, whose leading members were Funada FUMIAKI, with Yutaka ISHII as sub-leader, for LC material and operation mode and acting deputy to Matsuura, Kohzo YANO for TFT process, Hiroshi TAKE for system designing of TFT, LCD panel and driving circuitry, and evaluation of TFT-LCD as an integrated system, achieved and acquired them.

In the production project started in November 1985, LCD business group, headed by Mitsuo ISHII, located in Yamato-Kohriyama-shi, Nara-ken, joined the project, bringing in panel production technology including large mother glass handling know-hows, and, the thin-film solar battery group, headed by Toshio TAKEMOTO, located in Shinjoh-shi, Nara-ken, was also incorporated into ISHII"s group,afterward, bringing in amorphous-Silicon(a-Si) thin-film solar-cell mass-production technology whose basics are similar to those of a-Si TFT.

In the Japanese Consumer Electronics Show, October 1986, the production project demonstrated 3-inch TFT-LCD TV which employed a normally-white LCD operation mode. The mechanical design of the 3-inch TFT-LCD module mounted on the demonstrated TV was done by Kenichi UKAI who joined the project June 1986 from Electronic Component Business Division, whose main products included miniaturized electronic TV tuners, located in Osaka-shi, Osaka-fu.

The world-first TFT-LCD factory with a large mother glass 300mmx320mm was build in the precinct of Research and Development Group, located in Tenri-shi, Nara-ken, toward the end of 1986, near the Central Reaearch Laboratories TFT-LCD research group belonged to.

April 1987, YANO and TAKE of TFT-LCD research group moved to LCD Business Division whose general manager was Isamu WASHIZUKA, to be the technology and engineering core members of the newly-created The 3rd Production Department which had all the essential functions to execute TFT-LCD business, such as TFT-LCD process engineering, electronics and mechanical engineerings, administration, and production, irregularly incorporated with Mitsuo ISHII as general manager.

The 1st Sharp LC-TV "3C-E1" with 3-inch TFT-LCD, display dot 384Hx240V in a triangle arrangement, was put on the martket June 1987, half a year later than originally scheduled; the TFT-LCD production yield was miserable, though.

In one of meetings held everyday in the evening to improve production yield of 3-inch TFT-LCD panel, Washizuka gave an additional mission to look into the future, and to search for TFT-LCD technology capability for TV, and instigated young engineers to study and propose larger display prototype development plans without giving any clear target size numbers and time frames.

Around middle of 1987, a voluntary project team was set up, headed by Mitsuo ISHII, whose leading members were Toshio AKAI for product planning, Kohzo YANO for TFT-LCD process and Hiroshi TAKE for electronics and system.

The project team almost reached a consensus to adopt 8.9-in. size for a challenging target: 6.6-in. seemed to give only a small impact; 14-in. seemed to be too risky to get good panels, meaning with high display uniformity across the entire display area, no-line defects and acceptable dot defects by infant technology and equipment.

TAKE made a phone call to Magohiro ARAMOTO, general manager of TV Division, and had guided the TFT-LCD development project to improve display quality for TV, to try to understand the TV market, and asked ARAMOTO what would be the minimum size of TFT-LCD to be widely used by people.

TAKE, evaluation and characterization research engineer by background, knew the difficulty to prepare 14-in. panel using the same process and equipment used to mass-produce 3-in. panels with poor yield, but decided to accept ARAMOTO’s number 14-in., saying to himself the possible largest size on the mother glass would show up, more clearly than smaller sizes, problems and issues TFT-LCD had to solve and tackle with to be a viable technology in TV and other markets dominated by CRTs.

The panel should be compatible with NTSC/M TV system, and display dot number was decided to be 642Hx480V with available analog driver-LSI output terminal numbers taken into consideration. The trios of red, green and blue primary color dots were arranged in a triangle pattern to maximize the resolution with the limited display dot number.

The target TFT-LCD panel specifications was accepted in the project team after YANO, with Hiroaki KATOH as his process designing section leader, made a thorough review of the TFT-LCD process and equipment in the 3-in.-mass-producing factory to make sure 14-in. was NOT impossible　, and authorized by WASHIZUKA afterwards.

The 14-in. TFT-LCD panels were prepared by using the production line whose main product was 3-inch TFT-LCD panel, and 4-inch TFT-LCD production was just started.

There were a lot of fierce arguments and misunderstandings within the newly-formed production department whoes members had been recruited from various departments of various business divisions of Sharp Corporation, but those were managed and solved by tightly sharing the common mission: Make TV displays for OUR TVs!: Sharp Corporation mass-produced B/W CRT-TV in 1953, 1st in Japan, under the license agreement with RCA, and had been one of the leading worldwide TV makers, but had not produced CRTs inhouse; all CRTs on Sharp TVs been bought from outside.

At the very beginning of a-Si-TFT-LCD business startup, this work clearly showed a-Si-TFT-LCD have the potential to replace monster CRT in the coming information age by its superior characteristics: flatness, light-weight, small power consumption, high saturation full-color rendition, high readability in high ambient light, realized on the 14-in. display size, the most dominant size in the contemporary market by using the technology which was developed to mass-produce twenty 3-in. TFT-LCD TV panels laid out on the mother glass of 300mm x 320mm dimensions.

TV business group knew the market and joined the development project from the very beginning and gave a clear display quality target to TFT-LCD research group to achieve and make the TFT-LCD a viable display technology against CRT dominance.

[114] T. Nagayasu, T. Oketani, T. Hirobe, H. Kato, S. Mizushima, H. Take, K. Yano, M. Hijikigawa, and I. Washizuka, “A 14-in-diagonal full color a-Si TFT LCD,” in Proc. Int. Display Research Conf., San Diego, CA, Oct. 1988, pp. 56–58.

[9] G. H. Heilmeier, “Liquid crystal displays: An experiment in interdisciplinary research that worked,” IEEE Trans. Electron Devices, vol. ED-23, July 1976.

[２] B.J.Lechner, "History Crystallized_A First-Person Account of the Development of Matrix-Addressed LCDs for television at RCA in the 1960s",Information Display 1/08 p26-30

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