Sanyo Electric Co., Ltd.

Tottori Sanyo Electric Co., Ltd.

Kouji Maeta

Toshihiko Tanaka

Shoji Iwasaki

Jouji Yamada

Masahiro Nakamura

Norimitsu Kobayashi

Akinori Matsushita

Makoto Kasami

A simple matrix drive type liquid crystal display device with enhanced display quality is provided. In line-at-a-time scanning, a scanning electrode group is supplied with two selecting voltages alternately; a signal electrode group is supplied with two voltages close to the intermediate value between the two selecting voltages. Which voltage is applied to the signal electrode is determined in accordance with the selecting voltage applied to the scanning electrode at that moment and a video signal in such a way that selected picture elements receive a large voltage and non-selected picture elements receive a small voltage. The output voltage of the power source circuit, which supplies power to the scanning circuit and the signal circuit that apply voltages to the scanning and signal electrode groups, is monitored so that, if the voltage is below a predetermined value, the liquid display device will not start display even when it receives a signal requesting starting of display from the outside.

Liquid crystal display device

A driving power supply and a driving circuit are provided which are suitable for use in a high resolution matrix liquid crystal display. A power source circuit generates two selecting potentials and an intermediate potential between the selecting potentials to be supplied to scanning electrodes through a scanning circuit, two potentials close to the intermediate potential to be supplied to signal electrodes through a signal circuit, and potentials for driving the scanning circuit and the signal circuit. A receiving circuit controls the scanning circuit and the signal circuit based on control signals and an image signal and monitors the potential of the power supplied to the liquid crystal display to start the potential generation by the power source circuit when the potential has sufficiently increased.

Liquid crystal display

Growing community of inventors

Tottori, Japan

Kouji Maeta