tft lcd display wikipedia pricelist
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.
The transmittance of a pixel of an LCD panel typically does not change linearly with the applied voltage,sRGB standard for computer monitors requires a specific nonlinear dependence of the amount of emitted light as a function of the RGB value.
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.
Less expensive PVA panels often use dithering and FRC, whereas super-PVA (S-PVA) panels all use at least 8 bits per color component and do not use color simulation methods.BRAVIA LCD TVs offer 10-bit and xvYCC color support, for example, the Bravia X4500 series. S-PVA also offers fast response times using modern RTC technologies.
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.
Brody, T. Peter; Asars, J. A.; Dixon, G. D. (November 1973). "A 6 × 6 inch 20 lines-per-inch liquid-crystal display panel". 20 (11): 995–1001. Bibcode:1973ITED...20..995B. doi:10.1109/T-ED.1973.17780. ISSN 0018-9383.
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 TFT-LCD (Flat Panel) Antitrust Litigationclass-action lawsuit regarding the worldwide conspiracy to coordinate the prices of Thin-Film Transistor-Liquid Crystal Display (TFT-LCD) panels, which are used to make laptop computers, computer monitors and televisions, between 1999 and 2006. In March 2010, Judge Susan Illston certified two nationwide classes of persons and entities that directly and indirectly purchased TFT-LCDs – for panel purchasers and purchasers of TFT-LCD integrated products; the litigation was followed by multiple suits.
TFT-LCDs are used in flat-panel televisions, laptop and computer monitors, mobile phones, personal digital assistants, semiconductors and other devices;
In mid-2006, the U.S. Department of Justice (DOJ) Antitrust Division requested FBI assistance in investigating LCD price-fixing. In December 2006, authorities in Japan, Korea, the European Union and the United States revealed a probe into alleged anti-competitive activity among LCD panel manufacturers.
The companies involved, which later became the Defendants, were Taiwanese companies AU Optronics (AUO), Chi Mei, Chunghwa Picture Tubes (Chunghwa), and HannStar; Korean companies LG Display and Samsung; and Japanese companies Hitachi, Sharp and Toshiba.cartel which took place between January 1, 1999, through December 31, 2006, and which was designed to illegally reduce competition and thus inflate prices for LCD panels. The companies exchanged information on future production planning, capacity use, pricing and other commercial conditions.European Commission concluded that the companies were aware they were violating competition rules, and took steps to conceal the venue and results of the meetings; a document by the conspirators requested everybody involved "to take care of security/confidentiality matters and to limit written communication".
Companies directly affected by the LCD price-fixing conspiracy, as direct victims of the cartel, were some of the largest computer, television and cellular telephone manufacturers in the world. These direct action plaintiffs included AT&T Mobility, Best Buy,Costco Wholesale Corporation, Good Guys, Kmart Corp, Motorola Mobility, Newegg, Sears, and Target Corp.Clayton Act (15 U.S.C. § 26) to prevent Defendants from violating Section 1 of the Sherman Act (15 U.S.C. § 1), as well as (b) 23 separate state-wide classes based on each state"s antitrust/consumer protection class action law.
In November 2008, LG, Chunghwa, Hitachi, Epson, and Chi Mei pleaded guilty to criminal charges of fixing prices of TFT-LCD panels sold in the U.S. and agreed to pay criminal fines (see chart).
The South Korea Fair Trade Commission launched legal proceedings as well. It concluded that the companies involved met more than once a month and more than 200 times from September 2001 to December 2006, and imposed fines on the LCD manufacturers.
Sharp Corp. pleaded guilty to three separate conspiracies to fix the prices of TFT-LCD panels sold to Dell Inc., Apple Computer Inc. and Motorola Inc., and was sentenced to pay a $120 million criminal fine,
In South Korea, regulators imposed the largest fine the country had ever imposed in an international cartel case, and fined Samsung Electronics and LG Display ₩92.29 billion and ₩65.52 billion, respectively. AU Optronics was fined ₩28.53 billion, Chimmei Innolux ₩1.55 billion, Chungwa ₩290 million and HannStar ₩870 million.
Seven executives from Japanese and South Korean LCD companies were indicted in the U.S. Four were charged with participating as co-conspirators in the conspiracy and sentenced to prison terms – including LG"s Vice President of Monitor Sales, Chunghwa"s chairman, its chief executive officer, and its Vice President of LCD Sales – for "participating in meetings, conversations and communications in Taiwan, South Korea and the United States to discuss the prices of TFT-LCD panels; agreeing during these meetings, conversations and communications to charge prices of TFT-LCD panels at certain predetermined levels; issuing price quotations in accordance with the agreements reached; exchanging information on sales of TFT-LCD panels for the purpose of monitoring and enforcing adherence to the agreed-upon prices; and authorizing, ordering and consenting to the participation of subordinate employees in the conspiracy."
On December 8, 2010, the European Commission announced it had fined six of the LCD companies involved in a total of €648 million (Samsung Electronics received full immunity under the commission"s 2002 Leniency Notice) – LG Display, AU Optronics, Chimei, Chunghwa Picture and HannStar Display Corporation.
On July 3, 2012, a U.S. federal jury ruled that the remaining defendant, Toshiba Corporation, which denied any wrongdoing, participated in the conspiracy to fix prices of TFT-LCDs and returned a verdict in favor of the plaintiff class. Following the trial, Toshiba agreed to resolve the case by paying the class $30 million.
Flat-panel displays are thin panels of glass or plastic used for electronically displaying text, images, or video. Liquid crystal displays (LCD), OLED (organic light emitting diode) and microLED displays are not quite the same; since LCD uses a liquid crystal that reacts to an electric current blocking light or allowing it to pass through the panel, whereas OLED/microLED displays consist of electroluminescent organic/inorganic materials that generate light when a current is passed through the material. LCD, OLED and microLED displays are driven using LTPS, IGZO, LTPO, and A-Si TFT transistor technologies as their backplane using ITO to supply current to the transistors and in turn to the liquid crystal or electroluminescent material. Segment and passive OLED and LCD displays do not use a backplane but use indium tin oxide (ITO), a transparent conductive material, to pass current to the electroluminescent material or liquid crystal. In LCDs, there is an even layer of liquid crystal throughout the panel whereas an OLED display has the electroluminescent material only where it is meant to light up. OLEDs, LCDs and microLEDs can be made flexible and transparent, but LCDs require a backlight because they cannot emit light on their own like OLEDs and microLEDs.
Liquid-crystal display (or LCD) is a thin, flat panel used for electronically displaying information such as text, images, and moving pictures. They are usually made of glass but they can also be made out of plastic. Some manufacturers make transparent LCD panels and special sequential color segment LCDs that have higher than usual refresh rates and an RGB backlight. The backlight is synchronized with the display so that the colors will show up as needed. The list of LCD manufacturers:
Organic light emitting diode (or OLED displays) is a thin, flat panel made of glass or plastic used for electronically displaying information such as text, images, and moving pictures. OLED panels can also take the shape of a light panel, where red, green and blue light emitting materials are stacked to create a white light panel. OLED displays can also be made transparent and/or flexible and these transparent panels are available on the market and are widely used in smartphones with under-display optical fingerprint sensors. LCD and OLED displays are available in different shapes, the most prominent of which is a circular display, which is used in smartwatches. The list of OLED display manufacturers:
MicroLED displays is an emerging flat-panel display technology consisting of arrays of microscopic LEDs forming the individual pixel elements. Like OLED, microLED offers infinite contrast ratio, but unlike OLED, microLED is immune to screen burn-in, and consumes less power while having higher light output, as it uses LEDs instead of organic electroluminescent materials, The list of MicroLED display manufacturers:
Sony produces and sells commercial MicroLED displays called CLEDIS (Crystal-LED Integrated Displays, also called Canvas-LED) in small quantities.video walls.
LCDs are made in a glass substrate. For OLED, the substrate can also be plastic. The size of the substrates are specified in generations, with each generation using a larger substrate. For example, a 4th generation substrate is larger in size than a 3rd generation substrate. A larger substrate allows for more panels to be cut from a single substrate, or for larger panels to be made, akin to increasing wafer sizes in the semiconductor industry.
"Samsung Display has halted local Gen-8 LCD lines: sources". THE ELEC, Korea Electronics Industry Media. August 16, 2019. Archived from the original on April 3, 2020. Retrieved December 18, 2019.
"TCL to Build World"s Largest Gen 11 LCD Panel Factory". www.businesswire.com. May 19, 2016. Archived from the original on April 2, 2018. Retrieved April 1, 2018.
"Panel Manufacturers Start to Operate Their New 8th Generation LCD Lines". 대한민국 IT포털의 중심! 이티뉴스. June 19, 2017. Archived from the original on June 30, 2019. Retrieved June 30, 2019.
"Business Place Information – Global Operation | SAMSUNG DISPLAY". www.samsungdisplay.com. Archived from the original on 2018-03-26. Retrieved 2018-04-01.
"Samsung Display Considering Halting Some LCD Production Lines". 비즈니스코리아 - BusinessKorea. August 16, 2019. Archived from the original on April 5, 2020. Retrieved December 19, 2019.
Herald, The Korea (July 6, 2016). "Samsung Display accelerates transition from LCD to OLED". www.koreaherald.com. Archived from the original on April 1, 2018. Retrieved April 1, 2018.
Byeonghwa, Yeon. "Business Place Information – Global Operation – SAMSUNG DISPLAY". Samsungdisplay.com. Archived from the original on 2018-03-26. Retrieved 2018-04-01.
www.etnews.com (30 June 2017). "Samsung Display to Construct World"s Biggest OLED Plant". Archived from the original on 2019-06-09. Retrieved 2019-06-09.
"China"s BOE to have world"s largest TFT-LCD+AMOLED capacity in 2019". ihsmarkit.com. 2017-03-22. Archived from the original on 2019-08-16. Retrieved 2019-08-17.
Liquid-crystal-display televisions (LCD TVs) are television sets that use liquid-crystal displays to produce images. They are, by far, the most widely produced and sold television display type. LCD TVs are thin and light, but have some disadvantages compared to other display types such as high power consumption, poorer contrast ratio, and inferior color gamut.
LCD TVs rose in popularity in the early years of the 21st century, surpassing sales of cathode ray tube televisions worldwide in 2007.plasma display panels and rear-projection television.
Passive matrix LCDs first became common as portable computer displays in the 1980s, competing for market share with plasma displays. The LCDs had very slow refresh rates that blurred the screen even with scrolling text, but their light weight and low cost were major benefits. Screens using reflective LCDs required no internal light source, making them particularly well suited to laptop computers. Refresh rates of early devices were too slow to be useful for television.
Portable televisions were a target application for LCDs. LCDs consumed far less battery power than even the miniature tubes used in portable televisions of the era. In 1980, Hattori Seiko"s R&D group began development on color LCD pocket televisions. In 1982, Seiko Epson released the first LCD television, the Epson TV Watch, a small wrist-worn active-matrix LCD television. Sharp Corporation introduced the dot matrix TN-LCD in 1983, and Casio introduced its TV-10 portable TV.Citizen Watch introduced the Citizen Pocket TV, a 2.7-inch color LCD TV, with the first commercial TFT LCD display.
Throughout this period, screen sizes over 30" were rare as these formats would start to appear blocky at normal seating distances when viewed on larger screens. LCD projection systems were generally limited to situations where the image had to be viewed by a larger audience. At the same time, plasma displays could easily offer the performance needed to make a high quality display, but suffered from low brightness and very high power consumption. Still, some experimentation with LCD televisions took place during this period. In 1988, Sharp introduced a 14-inch active-matrix full-color full-motion TFT-LCD. These were offered primarily as high-end items, and were not aimed at the general market. This led to Japan launching an LCD industry, which developed larger-size LCDs, including TFT computer monitors and LCD televisions. Epson developed the 3LCD projection technology in the 1980s, and licensed it for use in projectors in 1988. Epson"s VPJ-700, released in January 1989, was the world"s first compact, full-color LCD projector.
In 2006, LCD prices started to fall rapidly and their screen sizes increased, although plasma televisions maintained a slight edge in picture quality and a price advantage for sets at the critical 42" size and larger. By late 2006, several vendors were offering 42" LCDs, albeit at a premium price, encroaching upon plasma"s only stronghold. More decisively, LCDs offered higher resolutions and true 1080p support, while plasmas were stuck at 720p, which made up for the price difference.
Predictions that prices for LCDs would rapidly drop through 2007 led to a "wait and see" attitude in the market, and sales of all large-screen televisions stagnated while customers watched to see if this would happen.Christmas sales season.
When the sales figures for the 2007 Christmas season were finally tallied, analysts were surprised to find that not only had LCD outsold plasma, but CRTs as well, during the same period.Pioneer Electronics was ending production of the plasma screens was widely considered the tipping point in that technology"s history as well.
In spite of LCD"s dominance of the television field, other technologies continued to be developed to address its shortcomings. Whereas LCDs produce an image by selectively blocking a backlight, organic LED, microLED, field-emission display and surface-conduction electron-emitter display technologies all produce an illuminated image directly. In comparison to LCDs all of these technologies offer better viewing angles, much higher brightness and contrast ratio (as much as 5,000,000:1), and better color saturation and accuracy. They also use less power, and in theory they are less complex and less expensive to build.
Manufacturing these screens proved to be more difficult than originally thought, however. Sony abandoned their field-emission display project in March 2009,
A thin-film transistor (TFT) is a special type of field-effect transistor (FET) where the transistor is thin relative to the plane of the device.substrate. A common substrate is glass, because the traditional application of TFTs is in liquid-crystal displays (LCDs). This differs from the conventional bulk metal oxide field effect transistor (MOSFET), where the semiconductor material typically is the substrate, such as a silicon wafer.
TFTs can be fabricated with a wide variety of semiconductor materials. Because it is naturally abundant and well understood, amorphous or polycrystalline silicon was historically used as the semiconductor layer. However, because of the low mobility of amorphous siliconcadmium selenide,metal oxides such as indium gallium zinc oxide (IGZO) or zinc oxide,organic semiconductors,carbon nanotubes,metal halide perovskites.
Because TFTs are grown on inert substrates, rather than on wafers, the semiconductor must be deposited in a dedicated process. A variety of techniques are used to deposit semiconductors in TFTs. These include chemical vapor deposition (CVD), atomic layer deposition (ALD), and sputtering. The semiconductor can also be deposited from solution,printing
Some wide band gap semiconductors, most notable metal oxides, are optically transparent.electrodes, such as indium tin oxide (ITO), some TFT devices can be designed to be completely optically transparent.head-up displays (such as on a car windshield).The first solution-processed TTFTs, based on zinc oxide, were reported in 2003 by researchers at Oregon State University.Universidade Nova de Lisboa has produced the world"s first completely transparent TFT at room temperature.
The best known application of thin-film transistors is in TFT LCDs, an implementation of liquid-crystal display technology. Transistors are embedded within the panel itself, reducing crosstalk between pixels and improving image stability.
As of 2008LCD TVs and monitors use this technology. TFT panels are frequently used in digital radiography applications in general radiography. A TFT is used in both direct and indirect capturemedical radiography.
The most beneficial aspect of TFT technology is its use of a separate transistor for each pixel on the display. Because each transistor is small, the amount of charge needed to control it is also small. This allows for very fast re-drawing of the display.
In February 1957, John Wallmark of RCA filed a patent for a thin film MOSFET in which germanium monoxide was used as a gate dielectric. 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. In 1966, T.P. Brody and H.E. Kunig at Westinghouse Electric fabricated indium arsenide (InAs) MOS TFTs in both depletion and enhancement modes.
The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard J. Lechner of RCA Laboratories in 1968.dynamic scattering LCD that used standard discrete MOSFETs, as TFT performance was not adequate at the time.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).electroluminescence (EL) in 1973, using CdSe.active-matrix liquid-crystal display (AM LCD) using CdSe in 1974, and then Brody coined the term "active matrix" in 1975.
A breakthrough in TFT research came with the development of the amorphous silicon (a-Si) TFT by P.G. le Comber, W.E. Spear and A. Ghaith at the University of Dundee in 1979. They reported the first functional TFT made from hydrogenated a-Si with a silicon nitride gate dielectric layer.research and development (R&D) of AM LCD panels based on a-Si TFTs in Japan.
By 1982, Pocket TVs based on AM LCD technology were developed in Japan.Fujitsu"s S. Kawai fabricated an a-Si dot-matrix display, and Canon"s Y. Okubo fabricated a-Si twisted nematic (TN) and guest-host LCD panels. In 1983, Toshiba"s K. Suzuki produced a-Si TFT arrays compatible with CMOS integrated circuits (ICs), Canon"s M. Sugata fabricated an a-Si color LCD panel, and a joint Sanyo and Sanritsu team including Mitsuhiro Yamasaki, S. Suhibuchi and Y. Sasaki fabricated a 3-inch a-SI color LCD TV.
The first commercial TFT-based AM LCD product was the 2.1-inch Epson ET-10Hitachi research team led by Akio Mimura demonstrated a low-temperature polycrystalline silicon (LTPS) process for fabricating n-channel TFTs on a silicon-on-insulator (SOI), at a relatively low temperature of 200°C.Hosiden research team led by T. Sunata in 1986 used a-Si TFTs to develop a 7-inch color AM LCD panel,Apple Computers.Sharp research team led by engineer T. Nagayasu used hydrogenated a-Si TFTs to demonstrate a 14-inch full-color LCD display,electronics industry that LCD would eventually replace cathode-ray tube (CRT) as the standard television display technology.notebook PCs.IBM Japan introduced a 12.1-inch color SVGA panel for the first commercial color laptop by IBM.
TFTs can also be made out of indium gallium zinc oxide (IGZO). TFT-LCDs with IGZO transistors first showed up in 2012, and were first manufactured by Sharp Corporation. IGZO allows for higher refresh rates and lower power consumption.polyimide substrate.
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.
Brody, T. Peter; Asars, J. A.; Dixon, G. D. (November 1973). "A 6 × 6 inch 20 lines-per-inch liquid-crystal display panel". 20 (11): 995–1001. Bibcode:1973ITED...20..995B. doi:10.1109/T-ED.1973.17780. ISSN 0018-9383.
Morozumi, Shinji; Oguchi, Kouichi (12 October 1982). "Current Status of LCD-TV Development in Japan". Molecular Crystals and Liquid Crystals. 94 (1–2): 43–59. doi:10.1080/00268948308084246. ISSN 0026-8941.
Mimura, Akio; Oohayashi, M.; Ohue, M.; Ohwada, J.; Hosokawa, Y. (1986). "SOI TFT"s with directly contacted ITO". IEEE Electron Device Letters. 7 (2): 134–6. Bibcode:1986IEDL....7..134M. doi:10.1109/EDL.1986.26319. ISSN 0741-3106. S2CID 36089445.
Sunata, T.; Yukawa, T.; Miyake, K.; Matsushita, Y.; Murakami, Y.; Ugai, Y.; Tamamura, J.; Aoki, S. (1986). "A large-area high-resolution active-matrix color LCD addressed by a-Si TFT"s". 33 (8): 1212–1217. Bibcode:1986ITED...33.1212S. doi:10.1109/T-ED.1986.22644. ISSN 0018-9383. S2CID 44190988.
Sunata, T.; Miyake, K.; Yasui, M.; Murakami, Y.; Ugai, Y.; Tamamura, J.; Aoki, S. (1986). "A 640 × 400 pixel active-matrix LCD using a-Si TFT"s". IEEE Transactions on Electron Devices. 33 (8): 1218–21. Bibcode:1986ITED...33.1218S. doi:10.1109/T-ED.1986.22645. ISSN 0018-9383. S2CID 6356531.
Nagayasu, T.; Oketani, T.; Hirobe, T.; Kato, H.; Mizushima, S.; Take, H.; Yano, K.; Hijikigawa, M.; Washizuka, I. (October 1988). "A 14-in.-diagonal full-color a-Si TFT LCD". Conference Record of the 1988 International Display Research Conference: 56–58. doi:10.1109/DISPL.1988.11274. S2CID 20817375.
Electrically operated display devices have developed from electromechanical systems for display of text, up to all-electronic devices capable of full-motion 3D color graphic displays. Electromagnetic devices, using a solenoid coil to control a visible flag or flap, were the earliest type, and were used for text displays such as stock market prices and arrival/departure display times. The cathode ray tube was the workhorse of text and video display technology for several decades until being displaced by plasma, liquid crystal (LCD), and solid-state devices such as thin-film transistors (TFTs), LEDs and OLEDs. With the advent of metal-oxide-semiconductor field-effect transistors (MOSFETs), integrated circuit (IC) chips, microprocessors, and microelectronic devices, many more individual picture elements ("pixels") could be incorporated into one display device, allowing graphic displays and video.
One of the earliest electronic displays is the cathode ray tube (CRT), which was first demonstrated in 1897 and made commercial in 1922.electron gun that forms images by firing electrons onto a phosphor-coated screen. The earliest CRTs were monochrome and were used primarily in oscilloscopes and black and white televisions. The first commercial colour CRT was produced in 1954. CRTs were the single most popular display technology used in television sets and computer monitors for over half a century; it was not until the 2000s that LCDs began to gradually replace them.
A derivative of CRTs were storage tubes, which had the ability to retain information displayed on them, unlike standard CRTs which need to be refreshed periodically. In 1968, Tektronix introduced the Direct-View Bistable Storage Tube, which went on to be widely used in oscilloscopes and computer terminals.
1968Direct-View Bistable Storage Tube CRT retains static information displayed upon it, written using a steerable electron beam that can be turned off. The DVBST was used in vector displays of early computers and in oscilloscopes.
1984 Super-twisted nematic display (STN LCD) to improve passive-matrix LCDs, allowing for the first time higher resolution panels with 540x270 pixels.
IMOD displays are now available in the commercial marketplace. QMT"s displays, using IMOD technology, are found in the Acoustic Research ARWH1 Stereo Bluetooth headset device, the Showcare Monitoring system (Korea), the Hisense C108,Freestyle Audio and Skullcandy. In the mobile phone marketplace, Taiwanese manufacturers Inventec and Cal-Comp have announced phones with Mirasol displays, and LG claims to be developing "one or more" handsets using Mirasol technology. These products all have only 2-color (black plus one other) "bi-chromic" displays. UniPixel"s TMOS and Pixtronix"s DMS display technologies utilize vertically and horizontally moving MEMS structures to modulate a backlight, respectively.
The technology is still in its nascent stages, and the project is unusual for Microsoft, which is not in the display business. There is a possibility that Microsoft will collaborate with a display manufacturer, but commercial production will not begin until at least 2013.
On 25 February 2011, Prysm announced that its high-definition stackable display tiles, powered by its Laser Phosphor Display (LPD) technology, are now available for shipping to customers.
Although MicroLED displays have not been mass-produced for home use, after pioneering the technology in 2012,China Star Optoelectronics Technology (CSoT) demonstrated a 3.3" transparent microLED display with around 45% transparency, also co-developed with PlayNitride.Plessey Semiconductors Ltd demonstrated a GaN-on-Silicon wafer to CMOS backplane wafer bonded native Blue monochrome 0.7" active-matrix microLED display with an 8-micron pixel pitch.Ostendo Technologies, Inc. demonstrated a vertically integrated LED that can emit light from red to blue, including white – from a monolithic InGaN-based LED device.
Many expect that quantum dot display technology can compete or even replace liquid crystal displays (LCDs) in near future, including the desktop and notebook computer spaces and televisions. These initial applications alone represent more than a $8-billion addressable market by 2023 for quantum dot-based components. Other than display applications, several companies are manufacturing QD-LED light bulbs; these promise greater energy efficiency and longer lifetime.
Glass substrate with ITO electrodes. The shapes of these electrodes will determine the shapes that will appear when the LCD is switched ON. Vertical ridges etched on the surface are smooth.
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directlybacklight or reflector to produce images in color or monochrome.seven-segment displays, as in a digital clock, are all good examples of devices with these displays. They use the same basic technology, except that arbitrary images are made from a matrix of small pixels, while other displays have larger elements. LCDs can either be normally on (positive) or off (negative), depending on the polarizer arrangement. For example, a character positive LCD with a backlight will have black lettering on a background that is the color of the backlight, and a character negative LCD will have a black background with the letters being of the same color as the backlight. Optical filters are added to white on blue LCDs to give them their characteristic appearance.
LCDs are used in a wide range of applications, including LCD televisions, computer monitors, instrument panels, aircraft cockpit displays, and indoor and outdoor signage. Small LCD screens are common in LCD projectors and portable consumer devices such as digital cameras, watches, digital clocks, calculators, and mobile telephones, including smartphones. LCD screens are also used on consumer electronics products such as DVD players, video game devices and clocks. LCD screens have replaced heavy, bulky cathode-ray tube (CRT) displays in nearly all applications. LCD screens are available in a wider range of screen sizes than CRT and plasma displays, with LCD screens available in sizes ranging from tiny digital watches to very large television receivers. LCDs are slowly being replaced by OLEDs, which can be easily made into different shapes, and have a lower response time, wider color gamut, virtually infinite color contrast and viewing angles, lower weight for a given display size and a slimmer profile (because OLEDs use a single glass or plastic panel whereas LCDs use two glass panels; the thickness of the panels increases with size but the increase is more noticeable on LCDs) and potentially lower power consumption (as the display is only "on" where needed and there is no backlight). OLEDs, however, are more expensive for a given display size due to the very expensive electroluminescent materials or phosphors that they use. Also due to the use of phosphors, OLEDs suffer from screen burn-in and there is currently no way to recycle OLED displays, whereas LCD panels can be recycled, although the technology required to recycle LCDs is not yet widespread. Attempts to maintain the competitiveness of LCDs are quantum dot displays, marketed as SUHD, QLED or Triluminos, which are displays with blue LED backlighting and a Quantum-dot enhancement film (QDEF) that converts part of the blue light into red and green, offering similar performance to an OLED display at a lower price, but the quantum dot layer that gives these displays their characteristics can not yet be recycled.
Since LCD screens do not use phosphors, they rarely suffer image burn-in when a static image is displayed on a screen for a long time, e.g., the table frame for an airline flight schedule on an indoor sign. LCDs are, however, susceptible to image persistence.battery-powered electronic equipment more efficiently than a CRT can be. By 2008, annual sales of televisions with LCD screens exceeded sales of CRT units worldwide, and the CRT became obsolete for most purposes.
Each pixel of an LCD typically consists of a layer of molecules aligned between two transparent electrodes, often made of Indium-Tin oxide (ITO) and two polarizing filters (parallel and perpendicular polarizers), the axes of transmission of which are (in most of the cases) perpendicular to each other. Without the liquid crystal between the polarizing filters, light passing through the first filter would be blocked by the second (crossed) polarizer. Before an electric field is applied, the orientation of the liquid-crystal molecules is determined by the alignment at the surfaces of electrodes. In a twisted nematic (TN) device, the surface alignment directions at the two electrodes are perpendicular to each other, and so the molecules arrange themselves in a helical structure, or twist. This induces the rotation of the polarization of the incident light, and the device appears gray. If the applied voltage is large enough, the liquid crystal molecules in the center of the layer are almost completely untwisted and the polarization of the incident light is not rotated as it passes through the liquid crystal layer. This light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black. By controlling the voltage applied across the liquid crystal layer in each pixel, light can be allowed to pass through in varying amounts thus constituting different levels of gray.
The chemical formula of the liquid crystals used in LCDs may vary. Formulas may be patented.Sharp Corporation. The patent that covered that specific mixture expired.
Most color LCD systems use the same technique, with color filters used to generate red, green, and blue subpixels. The LCD color filters are made with a photolithography process on large glass sheets that are later glued with other glass sheets containing a TFT array, spacers and liquid crystal, creating several color LCDs that are then cut from one another and laminated with polarizer sheets. Red, green, blue and black photoresists (resists) are used. All resists contain a finely ground powdered pigment, with particles being just 40 nanometers across. The black resist is the first to be applied; this will create a black grid (known in the industry as a black matrix) that will separate red, green and blue subpixels from one another, increasing contrast ratios and preventing light from leaking from one subpixel onto other surrounding subpixels.Super-twisted nematic LCD, where the variable twist between tighter-spaced plates causes a varying double refraction birefringence, thus changing the hue.
LCD in a Texas Instruments calculator with top polarizer removed from device and placed on top, such that the top and bottom polarizers are perpendicular. As a result, the colors are inverted.
The optical effect of a TN device in the voltage-on state is far less dependent on variations in the device thickness than that in the voltage-off state. Because of this, TN displays with low information content and no backlighting are usually operated between crossed polarizers such that they appear bright with no voltage (the eye is much more sensitive to variations in the dark state than the bright state). As most of 2010-era LCDs are used in television sets, monitors and smartphones, they have high-resolution matrix arrays of pixels to display arbitrary images using backlighting with a dark background. When no image is displayed, different arrangements are used. For this purpose, TN LCDs are operated between parallel polarizers, whereas IPS LCDs feature crossed polarizers. In many applications IPS LCDs have replaced TN LCDs, particularly in smartphones. Both the liquid crystal material and the alignment layer material contain ionic compounds. If an electric field of one particular polarity is applied for a long period of time, this ionic material is attracted to the surfaces and degrades the device performance. This is avoided either by applying an alternating current or by reversing the polarity of the electric field as the device is addressed (the response of the liquid crystal layer is identical, regardless of the polarity of the applied field).
Displays for a small number of individual digits or fixed symbols (as in digital watches and pocket calculators) can be implemented with independent electrodes for each segment.alphanumeric or variable graphics displays are usually implemented with pixels arranged as a matrix consisting of electrically connected rows on one side of the LC layer and columns on the other side, which makes it possible to address each pixel at the intersections. The general method of matrix addressing consists of sequentially addressing one side of the matrix, for example by selecting the rows one-by-one and applying the picture information on the other side at the columns row-by-row. For details on the various matrix addressing schemes see passive-matrix and active-matrix addressed LCDs.
LCDs, along with OLED displays, are manufactured in cleanrooms borrowing techniques from semiconductor manufacturing and using large sheets of glass whose size has increased over time. Several displays are manufactured at the same time, and then cut from the sheet of glass, also known as the mother glass or LCD glass substrate. The increase in size allows more displays or larger displays to be made, just like with increasing wafer sizes in semiconductor manufacturing. The glass sizes are as follows:
Until Gen 8, manufacturers would not agree on a single mother glass size and as a result, different manufacturers would use slightly different glass sizes for the same generation. Some manufacturers have adopted Gen 8.6 mother glass sheets which are only slightly larger than Gen 8.5, allowing for more 50 and 58 inch LCDs to be made per mother glass, specially 58 inch LCDs, in which case 6 can be produced on a Gen 8.6 mother glass vs only 3 on a Gen 8.5 mother glass, significantly reducing waste.AGC Inc., Corning Inc., and Nippon Electric Glass.
The origins and the complex history of liquid-crystal displays from the perspective of an insider during the early days were described by Joseph A. Castellano in Liquid Gold: The Story of Liquid Crystal Displays and the Creation of an Industry.IEEE History Center.Peter J. Wild, can be found at the Engineering and Technology History Wiki.
In 1922, Georges Friedel described the structure and properties of liquid crystals and classified them in three types (nematics, smectics and cholesterics). In 1927, Vsevolod Frederiks devised the electrically switched light valve, called the Fréedericksz transition, the essential effect of all LCD technology. In 1936, the Marconi Wireless Telegraph company patented the first practical application of the technology, "The Liquid Crystal Light Valve". In 1962, the first major English language publication Molecular Structure and Properties of Liquid Crystals was published by Dr. George W. Gray.RCA found that liquid crystals had some interesting electro-optic characteristics and he realized an electro-optical effect by generating stripe-patterns in a thin layer of liquid crystal material by the application of a voltage. This effect is based on an electro-hydrodynamic instability forming what are now called "Williams domains" inside the liquid crystal.
The MOSFET (metal-oxide-semiconductor field-effect transistor) was invented by Mohamed M. Atalla and Dawon Kahng at Bell Labs in 1959, and presented in 1960.Paul K. Weimer at RCA developed the thin-film transistor (TFT) in 1962.
In 1964, George H. Heilmeier, then working at the RCA laboratories on the effect discovered by Williams achieved the switching of colors by field-induced realignment of dichroic dyes in a homeotropically oriented liquid crystal. Practical problems with this new electro-optical effect made Heilmeier continue to work on scattering effects in liquid crystals and finally the achievement of the first operational liquid-crystal display based on what he called the George H. Heilmeier was inducted in the National Inventors Hall of FameIEEE Milestone.
In the late 1960s, pioneering work on liquid crystals was undertaken by the UK"s Royal Radar Establishment at Malvern, England. The team at RRE supported ongoing work by George William Gray and his team at the University of Hull who ultimately discovered the cyanobiphenyl liquid crystals, which had correct stability and temperature properties for application in LCDs.
The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968.dynamic scattering mode (DSM) LCD that used standard discrete MOSFETs.
On December 4, 1970, the twisted nematic field effect (TN) in liquid crystals was filed for patent by Hoffmann-LaRoche in Switzerland, (Swiss patent No. 532 261) with Wolfgang Helfrich and Martin Schadt (then working for the Central Research Laboratories) listed as inventors.Brown, Boveri & Cie, its joint venture partner at that time, which produced TN displays for wristwatches and other applications during the 1970s for the international markets including the Japanese electronics industry, which soon produced the first digital quartz wristwatches with TN-LCDs and numerous other products. James Fergason, while working with Sardari Arora and Alfred Saupe at Kent State University Liquid Crystal Institute, filed an identical patent in the United States on April 22, 1971.ILIXCO (now LXD Incorporated), produced LCDs based on the TN-effect, which soon superseded the poor-quality DSM types due to improvements of lower operating voltages and lower power consumption. Tetsuro Hama and Izuhiko Nishimura of Seiko received a US patent dated February 1971, for an electronic wristwatch incorporating a TN-LCD.
In 1972, the concept of the active-matrix thin-film transistor (TFT) liquid-crystal display panel was prototyped in the United States by T. Peter Brody"s team at Westinghouse, in Pittsburgh, Pennsylvania.Westinghouse Research Laboratories demonstrated the first thin-film-transistor liquid-crystal display (TFT LCD).high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.active-matrix liquid-crystal display (AM LCD) in 1974, and then Brody coined the term "active matrix" in 1975.
In 1972 North American Rockwell Microelectronics Corp introduced the use of DSM LCDs for calculators for marketing by Lloyds Electronics Inc, though these required an internal light source for illumination.Sharp Corporation followed with DSM LCDs for pocket-sized calculators in 1973Seiko and its first 6-digit TN-LCD quartz wristwatch, and Casio"s "Casiotron". Color LCDs based on Guest-Host interaction were invented by a team at RCA in 1968.TFT LCDs similar to the prototypes developed by a Westinghouse team in 1972 were patented in 1976 by a team at Sharp consisting of Fumiaki Funada, Masataka Matsuura, and Tomio Wada,
In 1983, researchers at Brown, Boveri & Cie (BBC) Research Center, Switzerland, invented the passive matrix-addressed LCDs. H. Amstutz et al. were listed as inventors in the corresponding patent applications filed in Switzerland on July 7, 1983, and October 28, 1983. Patents were granted in Switzerland CH 665491, Europe EP 0131216,
The first color LCD televisions were developed as handheld televisions in Japan. In 1980, Hattori Seiko"s R&D group began development on color LCD pocket televisions.Seiko Epson released the first LCD television, the Epson TV Watch, a wristwatch equipped with a small active-matrix LCD television.dot matrix TN-LCD in 1983.Citizen Watch,TFT LCD.computer monitors and LCD televisions.3LCD projection technology in the 1980s, and licensed it for use in projectors in 1988.compact, full-color LCD projector.
In 1990, under different titles, inventors conceived electro optical effects as alternatives to twisted nematic field effect LCDs (TN- and STN- LCDs). One approach was to use interdigital electrodes on one glass substrate only to produce an electric field essentially parallel to the glass substrates.Germany by Guenter Baur et al. and patented in various countries.Hitachi work out various practical details of the IPS technology to interconnect the thin-film transistor array as a matrix and to avoid undesirable stray fields in between pixels.
Hitachi also improved the viewing angle dependence further by optimizing the shape of the electrodes (Super IPS). NEC and Hitachi become early manufacturers of active-matrix addressed LCDs based on the IPS technology. This is a milestone for implementing large-screen LCDs having acceptable visual performance for flat-panel computer monitors and television screens. In 1996, Samsung developed the optical patterning technique that enables multi-domain LCD. Multi-domain and In Plane Switching subsequently remain the dominant LCD designs through 2006.South Korea and Taiwan,
In 2007 the image quality of LCD televisions surpassed the image quality of cathode-ray-tube-based (CRT) TVs.LCD TVs were projected to account 50% of the 200 million TVs to be shipped globally in 2006, according to Displaybank.Toshiba announced 2560 × 1600 pixels on a 6.1-inch (155 mm) LCD panel, suitable for use in a tablet computer,transparent and flexible, but they cannot emit light without a backlight like OLED and microLED, which are other technologies that can also be made flexible and transparent.
In 2016, Panasonic developed IPS LCDs with a contrast ratio of 1,000,000:1, rivaling OLEDs. This technology was later put into mass production as dual layer, dual panel or LMCL (Light Modulating Cell Layer) LCDs. The technology uses 2 liquid crystal layers instead of one, and may be used along with a mini-LED backlight and quantum dot sheets.
Since LCDs produce no light of their own, they require external light to produce a visible image.backlight. Active-matrix LCDs are almost always backlit.Transflective LCDs combine the features of a backlit transmissive display and a reflective display.
CCFL: The LCD panel is lit either by two cold cathode fluorescent lamps placed at opposite edges of the display or an array of parallel CCFLs behind larger displays. A diffuser (made of PMMA acrylic plastic, also known as a wave or light guide/guiding plateinverter to convert whatever DC voltage the device uses (usually 5 or 12 V) to ≈1000 V needed to light a CCFL.
EL-WLED: The LCD panel is lit by a row of white LEDs placed at one or more edges of the screen. A light diffuser (light guide plate, LGP) is then used to spread the light evenly across the whole display, similarly to edge-lit CCFL LCD backlights. The diffuser is made out of either PMMA plastic or special glass, PMMA is used in most cases because it is rugged, while special glass is used when the thickness of the LCD is of primary concern, because it doesn"t expand as much when heated or exposed to moisture, which allows LCDs to be just 5mm thick. Quantum dots may be placed on top of the diffuser as a quantum dot enhancement film (QDEF, in which case they need a layer to be protected from heat and humidity) or on the color filter of the LCD, replacing the resists that are normally used.
WLED array: The LCD panel is lit by a full array of white LEDs placed behind a diffuser behind the panel. LCDs that use this implementation will usually have the ability to dim or completely turn off the LEDs in the dark areas of the image being displayed, effectively increasing the contrast ratio of the display. The precision with which this can be done will depend on the number of dimming zones of the display. The more dimming zones, the more precise the dimming, with less obvious blooming artifacts which are visible as dark grey patches surrounded by the unlit areas of the LCD. As of 2012, this design gets most of its use from upscale, larger-screen LCD televisions.
RGB-LED array: Similar to the WLED array, except the panel is lit by a full array of RGB LEDs. While displays lit with white LEDs usually have a poorer color gamut than CCFL lit displays, panels lit with RGB LEDs have very wide color gamuts. This implementation is most popular on professional graphics editing LCDs. As of 2012, LCDs in this category usually cost more than $1000. As of 2016 the cost of this category has drastically reduced and such LCD televisions obtained same price levels as the former 28" (71 cm) CRT based categories.
Monochrome LEDs: such as red, green, yellow or blue LEDs are used in the small passive monochrome LCDs typically used in clocks, watches and small appliances.
Today, most LCD screens are being designed with an LED backlight instead of the traditional CCFL backlight, while that backlight is dynamically controlled with the video information (dynamic backlight control). The combination with the dynamic backlight control, invented by Philips researchers Douglas Stanton, Martinus Stroomer and Adrianus de Vaan, simultaneously increases the dynamic range of the display system (also marketed as HDR, high dynamic range television or FLAD, full-area local area dimming).
The LCD backlight systems are made highly efficient by applying optical films such as prismatic structure (prism sheet) to gain the light into the desired viewer directions and reflective polarizing films that recycle the polarized light that was formerly absorbed by the first polarizer of the LCD (invented by Philips researchers Adrianus de Vaan and Paulus Schaareman),
Due to the LCD layer that generates the desired high resolution images at flashing video speeds using very low power electronics in combination with LED based backlight technologies, LCD technology has become the dominant display technology for products such as televisions, desktop monitors, notebooks, tablets, smartphones and mobile phones. Although competing OLED technology is pushed to the market, such OLED displays do not feature the HDR capabilities like LCDs in combination with 2D LED backlight technologies have, reason why the annual market of such LCD-based products is still growing faster (in volume) than OLED-based products while the efficiency of LCDs (and products like portable computers, mobile phones and televisions) may even be further improved by preventing the light to be absorbed in the colour filters of the LCD.
A pink elastomeric connector mating an LCD panel to circuit board traces, shown next to a centimeter-scale ruler. The conductive and insulating layers in the black stripe are very small.
A standard television receiver screen, a modern LCD panel, has over six million pixels, and they are all individually powered by a wire network embedded in the screen. The fine wires, or pathways, form a grid with vertical wires across the whole screen on one side of the screen and horizontal wires across the whole screen on the other side of the screen. To this grid each pixel has a positive connection on one side and a negative connection on the other side. So the total amount of wires needed for a 1080p display is 3 x 1920 going vertically and 1080 going horizontally for a total of 6840 wires horizontally and vertically. That"s three for red, green and blue and 1920 columns of pixels for each color for a total of 5760 wires going vertically and 1080 rows of wires going horizontally. For a panel that is 28.8 inches (73 centimeters) wide, that means a wire density of 200 wires per inch along the horizontal edge.
The LCD panel is powered by LCD drivers that are carefully matched up with the edge of the LCD panel at the factory level. The drivers may be installed using several methods, the most common of which are COG (Chip-On-Glass) and TAB (Tape-automated bonding) These same principles apply also for smartphone screens that are much smaller than TV screens.anisotropic conductive film or, for lower densities, elastomeric connectors.
Monochrome and later color passive-matrix LCDs were standard in most early laptops (although a few used plasma displaysGame Boyactive-matrix became standard on all laptops. The commercially unsuccessful Macintosh Portable (released in 1989) was one of the first to use an active-matrix display (though still monochrome). Passive-matrix LCDs are still used in the 2010s for applications less demanding than laptop computers and TVs, such as inexpensive calculators. In particular, these are used on portable devices where less information content needs to be displayed, lowest power consumption (no backlight) and low cost are desired or readability in direct sunlight is needed.
A comparison between a blank passive-matrix display (top) and a blank active-matrix display (bottom). A passive-matrix display can be identified when the blank background is more grey in appearance than the crisper active-matrix display, fog appears on all edges of the screen, and while pictures appear to be fading on the screen.
Displays having a passive-matrix structure are employing Crosstalk between activated and non-activated pixels has to be handled properly by keeping the RMS voltage of non-activated pixels below the threshold voltage as discovered by Peter J. Wild in 1972,
STN LCDs have to be continuously refreshed by alternating pulsed voltages of one polarity during one frame and pulses of opposite polarity during the next frame. Individual pixels are addressed by the corresponding row and column circuits. This type of display is called response times and poor contrast are typical of passive-matrix addressed LCDs with too many pixels and driven according to the "Alt & Pleshko" drive scheme. Welzen and de Vaan also invented a non RMS drive scheme enabling to drive STN displays with video rates and enabling to show smooth moving video images on an STN display.
Bistable LCDs do not require continuous refreshing. Rewriting is only required for picture information changes. In 1984 HA van Sprang and AJSM de Vaan invented an STN type display that could be operated in a bistable mode, enabling extremely high resolution images up to 4000 lines or more using only low voltages.
High-resolution color displays, such as modern LCD computer monitors and televisions, use an active-matrix structure. A matrix of thin-film transistors (TFTs) is added to the electrodes in contact with the LC layer. Each pixel has its own dedicated transistor, allowing each column line to access one pixel. When a row line is selected, all of the column lines are connected to a row of pixels and voltages corresponding to the picture information are driven onto all of the column lines. The row line is then deactivated and the next row line is selected. All of the row lines are selected in sequence dur