Liquid crystal displays: The third generation

Abstract

Liquid crystal displays became commercialized in the mid-1970s and compact, attractive LCD calculators and watches soon became household items. Now, some 10 years later, low cost LCDs of this first generation are being made by the hundreds of millions. These displays are, for the most part, directly driven with each segment receiving full voltage. Today, we see more sophisticated LCDs appearing in industrial and consumer products. These second-generation LCDs, driven by some multiplexing scheme, provide a higher level of information content.This literature review and discussion deals with the third generation of LCDs which are based on the use of active matrix and thin-film electronic devices to drive a large number of picture elements (pixels) without the loss of contrast or angle of view. Silicon back-to-back diodes, ring diodes, and metal-insulator-metal, two-terminal devices as well as three-terminal, thin-film transistor devices using such semiconductor materials as amorphous silicon, polycrystalline silicon and cadmium selenide are discussed.