Patent ID: 6850218
Filing Date: 2005-02-01
Classification: G09G

Abstract:
1. A system for prewriting a video frame in a liquid crystal display, said system comprising: a liquid crystal display (LCD) having a matrix of liquid crystal pixels, said matrix further divided into a plurality of sub-matrices of pixels; at least one digital-to-analog converter (DAC) adapted to receive a digital input representative of an analog voltage and having an analog output adapted for applying the analog voltage to at least one of the pixels at a time; a plurality of column switches adapted for coupling the analog output of said at least one DAC to at least one of a plurality of columns of said LCD; a plurality of row switches adapted for selectively coupling the plurality of columns to the pixels of said LCD; logic circuits for calculating an average voltage value to be applied to each of the plurality of sub-matrices before applying final voltage values to each of the pixels of each of the sub-matrices, wherein the average voltage value is an average of the sum of the final voltage values; and logic circuits for controlling the plurality of column switches and the plurality of row switches so that each sub-matrix may be precharged with its calculated average voltage value, then each of the pixels charged with the final voltage value representative of that portion of the video frame represented by that pixel.