Title:
LIQUID CRYSTAL DISPLAY DEVICE
Document Type and Number:
Japanese Patent JPH0431822
Kind Code:
A
Abstract:
PURPOSE:To prolong the usable time of a battery by switching the brightness of a back-light so as to reduce the power consumption of the back-light when the voltage of the battery drops below a prescribed level. CONSTITUTION:A system control circuit 10 switches the brightness of a back- light 12 for illuminating a liquid crystal display panel 6 based on the detected result of an outside light sensor 8. Namely, when the circumference is bright, the brightness of the back-light 12 is increased so as to increase the brightness of a picture displayed on the panel 6 and, when the circumference is dark, the brightness of the back-light 12 is decreased so as to decrease the brightness of the picture. In addition, the circuit 10 detects the voltage V of a battery 2 and, when the voltage V drops below a prescribed reference level, decreases the brightness of the back-light 12 so as to reduce the power consumption of the back-light 12. Therefore, the usable time of the battery can be prolonged.
Inventors:
TORII YOSHINAGA
Application Number:
JP13746590A
Publication Date:
February 04, 1992
Filing Date:
May 28, 1990
Export Citation:
Assignee:
SONY CORP
International Classes:
G02F1/133; G09F9/00; G09G3/18; H02J7/00; H05B37/02; G01R19/165; (IPC1-7): G01R19/165; G02F1/133; G09F9/00; G09G3/18; H02J7/00; H05B37/02
Attorney, Agent or Firm:
Keiki Tanabe
Next Patent: JPH0431823