The history of liquid-crystal display and its industry Developments from 1964 to 1988
Blaze Display Technology Co., Ltd. | Updated: Nov 27, 2018
A. Dynamic Sacttering Mode (DSM) of Operation
In 1964 George Heilmeier discovered DSM and hence invented a liquid-crystal display. When a high electrical field is applied across two electrically conductive and transparent plates that sandwich negative, nematic liquid-crystals, the LC molecules go into a random motion thus scatter a light incident on the plate making screen appear in a white color.
In 1968 RCA held a press conference in New York City on the discovery of the flat electronic display. This caused the display researchers in the world jump in the research of making displays out of liquid crystals.
B. Pocket Calculator
As soon as they heard the news of RCA announcement, Sharp Corp. started the research on liquid crystals. In June 1973, T. Wada et al. developed and marketed a pocket calculator based on the DSM.
C. Twisted-Nematic (TN) Mode of Operation
Though it was a commercial success, the pocket calculator was the only DSM product that was offered to the market place; DSM was low in contrast and was not able to display color picture thus not applicable to television applications. It required an electrical current, though it was very small, thus was not suitable for use in digital watch, which is expected to have a long working life.
In 1970, Wolfgang Helfrich conceived an idea of solving the above problems. He switched polarized light by relaxing a twisted alignment of positive liquid crystals by applying an electrical field, now called TN (twisted nematic) mode, and Martin Schadt of Hoffmann-La Roche constructed such device.
Their February 1971 paper [2] excited the electronic display researchers and made them go into the work on the TN mode. It may not be an overstatement to say that their concept of controlling the amount of light by reorienting liquid crystals with applying electrical filed is the basis of the LCD industry today.
D. Digital Watch
In 1971, Optel and Microma marketed DSM watches, but the products stopped working in a short time because of the hydrolysis problem of Schiff s base LCs. In September 1973, based on the TN mode and using azoxy compounds, SuwaSeikn marketed the first commercia 1 T. Cf) digital watch
E. Cyanobiphenyl Liquid-Crystals
The LC materials used when the DSM was discovered became the LC state in the temperature range of 117 °C to 134°C The first task at RCA was to find LC materials that work in room temperatures, which turned out to be Schiff s bases, and Sharp used them in the pocket calculator. But the materials were easily hydrolyzed thus had to be tightly sealed for reliability. In 1973, based on the TN mode, a British team made of RRE and Hull University headed by George Gray, synthesized cyanobiphenyl liquid-crystals (Fig. 5), which solved shortcomings of Schiff's bases and thus gave LCD the first commercial success.
F. TFT (Thin-Film Transistor) Active-Matrix Drive
Engineers tried to use the TN mode for scanning a dot matrix scheme, but they could not achieve more than 60 scanning lines. A Super TN mode was discovered, but was not proper for graphic display. Back in 1968, Bernard Lechner of RCA had conceived the idea of driving the matrix scheme by placing TFTs at each dots.
In 1973 Peter Brody, Fang Luo et al. of Westinghouse constructed the first dot-matrix display, 6-in. × 6-in., with using CdSe as base TFT material.
G. Fourteen-Inch TV-Type Display
In 1979 the University of Dundee in Scotland invented hydrogen-added amorphous silicon for use in TFT, replacing CdSe. This made it possible to construct LCD TV s. The size of TV started from 2.3-in., then to 3-in. and up to 12.5-in. [3]. In 1988 Washizuka, Take, Yano et al. of Sharp demonstrated a 14-in. full-color, full-motion display, the size of which at minimum could be defined as the size of a table-top television, not of portable type [4].
This convinced the electronic industry that LCD would soon replace existing cathode ray tube (CRT), and thus caused giant electronic-companies join the burgeoning LCD industry. This 14-in. display vaulted the LCD industry to the major league status.