Patent ID: 6414664
Filing Date: 2002-07-02
Classification: G09G

Abstract:
A method for controlling contrast in a liquid crystal display (â€œLCDâ€ ) device in which a full gray scale comprising minimum light out to maximum light out is used with variable video signal input ranges, with each video signal input range comprising a fraction of a total range of zero to full amplitude to be displayed by the LCD device, the full gray scale having a finite number of shades of gray, the LCD device having a contrast control for input by a user, the LCD device communicating with a drive voltage generator that supplies drive voltages V to the LCD device corresponding to the video signal input and a user contrast control setting, the method comprising the steps of:providing a plurality of look-up tables, the plurality of look-up tables representing a plurality of contrast settings of the LCD device; and selecting a single look-up table from the plurality of look-up tables in response to the contrast control setting selected by the user from the plurality of contrast settings through the contrast control device to affect a transfer function of the LCD device, the single look-up table containing all shade of gray available on the gray scale with each contrast setting.