Patent ID: 7027025

Claim:
A liquid crystal display device, which has pixels arranged in the form of a matrix, with each group of pixels forming respective lines extending along gate signal lines, and which comprises means for alternating the polarities of voltages applied to a liquid crystal during a frame period with respect to an alternation signal, comprising: means for accumulating signal levels of pixel data for odd-numbered lines of the pixels for every frame period; means for accumulating signal levels of pixel data for even-numbered lines of the pixels for every frame period; subtracting means for obtaining a subtracted value by subtracting one of the accumulated values of the signal levels for the odd-numbered lines and one of the accumulated values of the signal levels for the even-numbered lines from one another; and alternation signal transmitter means for transmitting an alternation signal different from a current alternation signal when, the subtracted value obtained by the subtracting means is not less than a reference value.