Patent ID: 7768489

Claim:
A method for driving a liquid crystal display (LCD) comprising a liquid crystal layer, a thin film transistor (TFT) comprising a source for receiving a source signal, a pixel electrode coupled to a drain of the TFT, and a counter electrode for receiving a common signal with a predetermined voltage, wherein a brightness of the LCD is brighter when a voltage difference between the pixel electrode and the counter electrode is higher, the method comprising: driving the LCD by applying uncompensated source signals corresponding to gray levels; recording first optimized common signal voltages of a plurality of common signals corresponding to the gray levels; and adjusting the source signal to drive the LCD such that second optimized common signal voltages of the common signals corresponding to the gray levels conform to either of the following conditions: (1) when the gray level is lower than a predetermined gray level, the second optimized common signal voltage is higher than the predetermined voltage of the common signal, and the absolute difference between the second optimized common signal voltage and the predetermined voltage is less than or equal to that between the first optimized common signal voltage and the predetermined voltage; and (2) when the gray level is not lower than the predetermined gray level, the absolute difference between the second optimized common signal voltage and the predetermined voltage is less than or equal to that between the first optimized common signal voltage and the predetermined voltage.