DRIVING METHOD TO IMPROVE RESPONSE TIME OF TWISTED NEMATIC AND SUPER TWISTED NEMATIC LCDS WITHOUT INCREASING GRAM

摘要

A method for improving response time of TN(Twisted Nematic) and STN(Super Twisted Nematic) LCD(Liquid Crystal Display) devices without increasing GRAM is provided to suppress flickers by utilizing an over drive voltage compensation scheme. When current data is different from previous image data, overdrive data of three primary colors are outputted by processing three primary color data based on an overdrive scheme through a motion determination mechanism. The three primary color data is converted into YCbCr data. The overdrive data of three primary colors is converted into overdrive V'Cb'Cr' data. The YCbCr data and the overdrive V'Cb'Cr' data are processed based on video compression standard. Bit allocation on the reduced YCbCr and V'Cb'Cr' data is performed based on the process. YCbCr data reduced by reducing CbCr storing bits of the YCbCr data and overdrive V'Cb'Cr' data reduced by reducing V'Cb'Cr' storing bits of the overdrive V'Cb'Cr' data are stored in a GRAM(Graphic Random Access Memory)(21). An overdrive compensation voltage level higher than or lower than an original output voltage level is provided n times according to the overdrive data within an update period of respective data buses through an output frequency multiplying circuit.