A Mixed Drive Method for High Gray Scale TFT-LCD

A novel mix-control grey scale modulation method is proposed. It features spatial modulation, temporal modulation and amplitude modulation and outperforms traditional methods for high grey scale TFT-LCD display in terms of clock frequency, complexity of driving circuits and so on. In the method, we take into consideration of human visual characters and employ dithering algorithm, frame rate control (FRC) and voltage amplitude DAC (VADAC) to approach the modulation process. In this way, bit width of source driver IC could be reduced while the display grey scale of the input image almost remains its original levels. We implemented the proposed method on an FPGA platform. Experimental result has indicated that, without obvious increase of lock frequency or hardware complexity, the structure can achieve 256 level (pseudo 1024 level) grey scale display on 6-bit TFT-LCD with satisfied visual effect, which has presented us a new approach to achieve high grey scale display.