Patent ID: 6140989
Filing Date: 2000-10-31
Classification: G09G,H03M

Abstract:
An image signal control circuit for converting digital image data into analog image data and sending the data to source driving means for driving a source line of a multi-gradation liquid crystal display, comprising:digital-to-analog conversion means having a first reference voltage terminal to be supplied with a predetermined voltage value and second and third reference voltage terminals to be supplied with a gradation voltage value for the voltage value applied to the first reference voltage terminal for outputting, as analog image data, one value of gradated analog gradation data obtained by the division of the gradation voltage, andcontrol means for receiving input of digital image data, sample hold input clock and frame input clock, wherein said control means is operative to switch the polarity of said analog image data output from said digital-to-analog conversion means at every frame period by controlling said digital-to-analog conversion means based on the values of said digital image data said sample hold input clock and said frame input clock.