Patent ID: 8125433
Filing Date: 2012-02-28
Classification: G09G

Abstract:
1. A liquid crystal display device, comprising: a liquid crystal display panel for displaying gray levels by a potential difference between a common electrode for applying a variable common voltage and pixel electrodes for applying data voltages; a common voltage regulating circuit for generating the variable common voltage which is longitudinally symmetrical with respect to a DC common voltage of a predetermined level and whose voltage level is stepwisely varied at predetermined intervals; a black gamma reference voltage regulating circuit for adding the variable common voltage to an offset voltage set as a gamma reference voltage of a black gray level to generate a variable gamma reference voltage varying with respect to the gamma reference voltage of the black gray level; and a data drive circuit for converting a digital video data into a gamma compensation voltage, whose level is sequentially varied, on the basis of the variable gamma reference voltage supplied from the black gamma reference voltage regulating circuit, and for supplying the gamma compensation voltage as the data voltage of a black gray level to data lines of the liquid crystal display panel, wherein the variable gamma reference voltage is varied in synchronization with the variable common voltage.