Liquid crystal display having common voltages

摘要

A liquid crystal display including a plurality of pixels arranged in a matrix includes a variable common voltage generator. The variable common voltage generator includes a frame memory storing image data for one frame, an average gray calculator calculating the average gray of the image data for one frame, a comparator comparing the calculated average gray from the average gray calculator with a reference gray and generating an adjusting value based on the compared result, and a D/A converter selecting a voltage having an appropriate value among a plurality of voltages generated based on the adjusting value from the comparator and applying the selected voltage as a common voltage.