Patent ID: 6417827
Filing Date: 2002-07-09
Classification: G09G

Abstract:
A liquid crystal display device comprising:a liquid crystal panel having a plurality of scanning signal lines and a plurality of video signal lines and having a plurality of pixels to which video signal voltages corresponding to A number of pieces of display data are to be applied via the video signal lines by a plurality of video signals; and video signal line driving means for supplying to the video signal lines the video signal voltages corresponding to the A number of pieces of display data, the video signal line driving means having: a power source circuit for outputting K number of grayscale reference voltages; a plurality of grayscale generation circuits for generating grayscale voltages corresponding to the A number of pieces of display data, for the respective video signal lines; and a video signal line driving circuit made of a plurality of amplifier circuits and output selecting circuits for amplifying the grayscale voltages and outputting video signal voltages corresponding to the display data to the respective video signal lines, the video signal lines driving means including: grayscale voltage generation means for dividing the K number of grayscale reference voltages outputted from the power source circuit to generate M-level grayscale voltages and selecting one of the generated grayscale voltages; and output means for making maximum output levels for N grayscale levels out of the M grayscale levels greater than maximum output levels for the other (Mâˆ’N) grayscale levels, the grayscale voltage generation means being a grayscale voltage selection circuit having switching elements corresponding to the A number of pieces of display data; among switching elements for selecting display data for the N grayscale levels, switching elements corresponding to the B number of pieces of display data among the A number of pieces of display data having the switching characteristics of being turned on or off at all the N grayscale levels, and on-resistances of switching elements corresponding to (Aâˆ’B) number of pieces of display data being smaller than on-resistances of switching elements for selecting display data for the (Mâˆ’N) grayscale levels.