The History of LCD Technology

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When Friedrich Reinitzer first observed the liquid crystal structure and behavior of the cholesterol from carrots in 1888, a world of liquid crystal technology was opened. He discovered that these liquid crystals had two melting points: one at which the crystals melt and create a cloudy liquid and another at which it melts a second time to become clear. It was also found that these crystals had color generation properties. However, this was far from what consists of our modern LCD (liquid crystal display).

Twenty-three years after Reinitzer, Charles Mauguin was the first to begin placing thin layers of liquid crystals between plates, an idea that would later found the structural concept of LCDs. A man named Georges Friedel first classified liquid crystal structures in 1922, separating them into nematics, smectic, and cholesterics. It was also discovered in 1962 by Richard Williams of the Radio Corporation of America (RCA) that these liquid crystal structures have electro-optical effects that can be controlled through an applied voltage.

 

Who invented the LCD, and When?

The liquid crystal research of the 1960s was characterized by the discovery of and experiments on the properties of the liquid crystals. George H. Heilmeier of the RCA based his research on that of Williams, diving into the electro-optical nature of the crystals. After many attempts to use the liquid crystals to display different colors, he created the first working LCD using something called a dynamic scattering mode (DSM) that, when voltage is applied, turns the clear liquid crystal layer into a more translucent state. Heilmeier was thus deemed the inventor of the LCD.

Evolution of LCD and Important Milestones

In the late 1960s, the United Kingdom Royal Radar Establishment (RRE) discovered the cyanobiphenyl liquid crystal, a type that was fitting for LCD usage in terms of stability and temperature. In 1968, Bernard Lechner of RCA created the idea of a TFT-based LCD, and in that same year, he and several others brought that idea into reality using Heilmeier’s DSM LCD.

After the LCD’s entrance into the field of display technology, the 1970s were full of expansive research into improving the LCD and making it appropriate for a greater variety of applications. In 1970, the twisted nematic field effect was patented in Switzerland with credited inventors being Wolfgang Helfrich and Martin Schadt. This twisted nematic (TN) effect soon conjoined with products that entered the international markets like Japan’s electronic industry. In the US, the same patent was filed by James Fergason in 1971. His company, ILIXCO, known today as LXD Incorporated, manufactured TN-effect LCDs which grew to overshadow the DSM models. TN LCDs offered better features like lower operating voltages and power consumption.

 

From this, the first digital clock, or more specifically an electronic quartz wristwatch, using a TN-LCD and consisting of four digits was patented in the US and released to consumers in 1972. Japan’s Sharp Corporation, in 1975, began mass production of digital watch and pocket calculator TN LCDs, and eventually, other Japanese corporations began to rise in the market for wristwatch displays. Seiko, as an example, developed the first six-digit TN-based LCD quartz watch, an upgrade from the original four-digit watch.

 

Nevertheless, the DSM LCD was not rendered completely useless. A 1972 development by the North American Rockwell Microelectronics Corp integrated the DSM LCD into calculators marketed by Lloyds Electronics. These required a form of internal light to show the display, and so backlights were also incorporated into these calculators. Shortly after, in 1973, Sharp Corporation brought DSM LCD pocket-sized calculators into the picture. A polymer called polyimide was used as the orientation layer of liquid crystal molecules.

Thin film transistor (TFT) LCDs had been introduced in 1968 by the RCA, but the active-matrix TFT LCD panel that consumers are most familiar with today for high-resolution displays was not prototyped until 1972. Throughout the 1970s, however, the TFT struggled to resolve many issues with composition materials, and so the technologies of the 70s did not utilize the TFT.

In the 1980s, there was rapid progress made in creating usable products with this new LCD research. Color LCD television screens were first developed in Japan during this decade. Because of the limit in response times due to large display size (correlated with a large number of pixels), the first TVs were handheld/pocket TVs. Seiko Epson, or Epson, created the first LCD TV, releasing it to the public in 1982, which was soon followed by their first fully colored display pocket LCD TV in 1984. Also in 1984 was the first commercial TFT LCD display: Citizen Watch’s 2.7 inch color LCD TV. Shortly after, in 1988, Sharp Corporation created a 14 inch full-color TFT LCD that used an active matrix and had full-motion properties. Large-size LCDs now made LCD integration into large flat-panel displays like LCD screens and LCD monitors possible. LCD projection technology, first created by Epson, became readily available to consumers in compact and fully colored modes in 1989.

The LCD growth in the 1990s focused more on the optical properties of these new displays in attempts to advance their quality and abilities. Hitachi engineers were integral to the analysis of in-plane switching (IPS) technology in TFT active matrices, a concept that would expand viewing angles of devices that used this technique, especially large-screen LCDs. Another technique that was developed in the 90s was multi-domain vertical alignment (MVA), developed by Samsung. Both the IPS and MVA techniques grew in popularity due to their abilities to widen viewing angles, making displays more desirable and useful. As this research went on, the LCD industry, previously centered in Japan, began expanding and moving towards South Korea, Taiwan, and later China as well.

 

When did LCD Monitors Become Popular? 

As we entered the new century, the prominence of LCDs boomed. They surpassed the previously popular cathode-ray tube (CRT) displays in both image quality and sales across the world in 2007. Other developments continued to be made, such as the manufacturing of even larger displays, adoption of transparent and flexible materials for LCD hardware, and creation of more methods to widen viewing angles (O-film).

 

How does an LCD Work?

As of today, as LCD displays have developed quite a bit, but have remained consistent in structure. Illuminated by a backlight, the display consists of, from outermost to innermost two polarizers, two substrates (typically glass), electrodes, and the liquid crystal layer. Closer to the surface is sometimes a color filter as well, using an RGB scheme. As light passes through the polarizer closest to the backlight, it enters the liquid crystal layer. Now, depending on whether an electric field directed by the electrodes is present, the liquid crystal will behave differently. Whether using a TN, IPS, or MVS LCD, the electrode electric field will alter the orientation of the liquid crystal molecules to then affect the polarization of the passing light. If the light is polarized properly, it will pass completely through the color filter and surface polarizer, displaying a certain color. If partially polarized correctly, it will display a medium level of light, or a less bright color. If not polarized properly, the light will not pass the surface, and no color will be displayed.

 

The Milestones of LCD Technology are listed as below,

1888: Friedrich Reinitzer, an Austrian botanist discovered liquid crystal phase transition phenomenon

1889: Otto Lehmann, Physicist in Germany, coined the term “liquid crystal”

1911: Charles Mauguin, University of Paris, discovered the unique alignment liquid crystal material adopts on various surfaces.

1922: Georges Friedel in France named the three main liquid crystal phases smectic, nematic, and cholesteric.

1927: Vsevolod Frederiks in Russian devised the electrically switched light valve, called the Fréedericksz transition, the essential effect of all LCD technology.

1929: Zocher and Birstein in Germany first studied effects of magnetic and electric fields on liquid crystals.

1936: Barnett Levin and Nyman Levin, Marconi Wireless Telegraph Company in England, obtained the first patent on a liquid crystal light valve.

1959: Mohamed M. Atalla and Dawon Kahng at Bell Labs invented MOSFET (metal-oxide-semiconductor field-effect transistor).

1962: Paul Weimer developed the first thin film transistor (TFT) at RCA’s David Sarnoff Research Center.

1962: George Gray, University of Hull in England, published the first book on liquid crystal structure and properties.

1963: Richard Williams reported the formation of domains in a nematic liquid crystal under electrical excitation.

1966: Joseph Castellano and Joel Goldmacher developed the first l cyanobiphenyls liquid crystal material that operated at or below room temperature.

1967: Bernard Lechner, Frank Marlowe, Edward Nester and Juri Tults built the first LCD to operate at television rates using discrete MOS transistors wired to the device.

1968: A research group at RCA laboratories in the US, headed by George Heilmeier, developed the first LCDs based on DSM (dynamic scattering mode) and the first bistable LCD using a mixture of cholesteric and nematic liquid crystals. The result sparked a worldwide effort to further develop LCDs. George H. Heilmeier was inducted in the National Inventors Hall of Fame and credited with the invention of LCDs. Heilmeier’s work is an IEEE Milestone.

1969: James Fergason, an associate director of Liquid Crystal Institute at Kent State University in Ohio, discovered the TN (twisted nematic) field effect.

1979, Peter Le Comber and Walter Spear at University of Dundee discovered that hydrogenated amorphous silicon (Alpha-Si:H) thin film transistors were suitable to drive LCDs. This is the major breakthrough that led to LCD television and computer displays.

1970: Hosiden and NEC built first LCD use a co-planar electrode structure for in-plane switching (IPS)

1970: Nunzio Luce of Optel Corporatoin, Princeton, New Jersey designed the first integrated circuit chip for an LCD watch.

1972: S. Kobayashi in Japan produced first defect free LCD.

1972: Tadashi Sasaki and Tomio Wada at Sharp Corporation built a prototype desktop calculator with a dynamic scattering LCD and started a program to build the first truly portable handheld calculator.

1972: Wolfgang Helfrich and Martin Schadt at Hoffmann La Roche built the first twisted nematic (TN) LCD device.

1972: Sun Lu and Derek Jones at Riker-Maxson in New York built the first digital watch using the twisted nematic (TN).

1973: G. Gray of BDH Ltd in the UK invented biphenyl liquid crystal material, allowing better operating performance and low cost LCD manufacturing.

Biphenyl compounds in mixture E-7, the most famous and widely used materials in early LCD manufacturing.

1975: Ludwig Pohl, Rudolf Eidenshink at E.Merck developed non-ester, cyanophenylcyclohexane liquid crystal materials which were more stable and became widely used in TFT(Thin Film Transistor) LCDs.

Canophenylcyclohexanes developed by E.Merck

 

Thin Film Transistor (TFT) Cell

1983: Colin Waters, V.Brimmel, and Peter Raynes at RSRE in England demonstrated a supertwisted nematic, guest host LCD.

1983: Shinji Morozumi at Suwa Seikosha demonstrated the world’s first commercial color LCD television with a 2 inch TN LCD driven by an active matrix of polycrystalline Si thin film transistors. This was a major milestone in the development of LCDs and started the drive toward larger screen displays.

1985:Terry Scheffer and Jurgen Nehring at Brown Boveri in Switzerland built the first STN (super twisted nematic) field effect.

1988: Hiroshi Take, Kozo Yano and Isamu Washizuka at Sharp Laboratories in Japan built the world’s first defect free 14 inch color active matrix LCD made with amorphous Si TFT.

1992: Hitachi developed In-plane Switching (IPS) and Super IPS LCD devices.

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.

2001: Samsung produced 42″ TFT LCD.

2002: LCD overtook CRT as desktop monitors.

2007: The image quality of LCD televisions surpassed the image quality of cathode-ray-tube-based (CRT) TVs. In the fourth quarter of 2007, LCD televisions surpassed CRT TVs in worldwide sales for the first time.

 

Mother Glass Generation History

Generation Length [mm] Height [mm] Year of introduction
GEN 1 200-300 200-400 1990
GEN 2 370 470
GEN 3 550 650 1996-1998
GEN 3.5 600 720 1996
GEN 4 680 880 2000-2002
GEN 4.5 730 920 2000-2004
GEN 5 1100 1250-1300 2002-2004
GEN 6 1500 1800–1850 2002-2004
GEN 7 1870 2200 2006
GEN 7.5 1950 2250
GEN 8 2160 2460
GEN 8.5 2200 2500
GEN 10 2880 3130 2009
GEN 10.5 (also known as GEN 11) 2940 3370 2018[26]

 

Panel Size Generation

 

References:

1, Liquid Gold: The Story of Liquid Crystal Displays and the Creation of an Industry, Joseph A. Castellano, 2005 World Scientific Publishing Co. Pte. Ltd., ISBN 981-238-956-3.

2, Kawamoto, Hiroshi (2002). “The History of Liquid-Crystal Displays” . Proceedings of the IEEE. 90 (4): 460–500. doi:10.1109/JPROC.2002.1002521.