Peripheral circuit integrated poly-Si TFT LCD with gray scale representation

A 3.3-in.-diagonal fully-integrated low-temperature-processed poly-Si TFT LCD (thin-film transistor liquid-crystal diode) with 4 gray scale (64 colours) representation was fabricated on a glass substrate. Good viewing characteristics, with a high contrast ratio more than 25 were obtained. Integrated data drive circuits consisted of divided matrix switches, line memories, and multilevel selectors. High-frequency drive capability was realized by using divided matrix switches with small line memory capacitance. Four-level gray-scale voltage was generated by the multilevel selectors. Integrated scan drive circuits consist of shift registers, level shifters, ratioless buffers, and multiplexers. Using a ratioless buffer, high-speed operation and low-power consumption was realized. By integrating peripheral drive circuits in a prototype display with (132*3)*133 dots, the number of external connections was reduced from 531 to 101. The maximum scan and data frequencies were 100 kHz and 10 MHz, respectively. These integrated peripheral circuits were capable of driving a display with (640*3)*400 dots at a frame frequency of 60 Hz.<>