The History of LCD Technology

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.

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.