Liquid crystal backlight controller

Abstract

Abstract PURPOSE:To prevent the waste of a battery power source by providing a photodetector which responds to visible light on the bottom part of a photodetecting hole having an opening part on the liquid crystal display surface side of a liquid crystal plate holding tool. CONSTITUTION:There is a hole-like photodetecting hole 5 on a liquid crystal display surface 7, and there is a photodetecting device 6 on the bottom part of the hole 5. A shape of the hole 5 is like a hole, and structured so that only a light beam from the direction C vertical to the liquid crystal display surface 7 reaches directly the device 6. The output of the device 6 is brought to current amplification by an amplifier 9, inputted to a control terminal 10a of a lighting control part 10, and controls opening/closing of a switch 10b. A backlight 4 is driven by a backlight use power source 11. In such a case, sensitivity of the amplifier 9 is set so as to close the switch 10b of the lighting control part 10, when an external light by which the display contents of a liquid crystal display device 2 can be read enough even if the backlight 4 is turned off is made incident directly on the device 6. In such a way, waste of a battery power source can be prevented.

Inventors

• 👤 Toshiaki Miyazaki
• 👤 敏明 宮崎

Bibliographic Details