《LCD驱动原理介绍》PPT课件.ppt

2019/9/20,1,crosstalk,Crosstalk is the different visible contrast of the OFF segments Crosstalk appears when the electro-optical state of individual pixels are affected by the electro-optical states of other pixels,2019/9/20,2,crosstalk,Crosstalk effects are correlated to the nonideal display components: the nonzero sheet resistance of the ITO - electrodes the output impedance of the row and column drivers acting in combination with the pixel capacitance entails a distortion of the addressing waveform,2019/9/20,3,crosstalk,min. frequency,horizontal crosstalk,Vertical + horizontal crosstalk,max. frequency,2019/9/20,4,crosstalk,Column all off or on,Column checkerboard,2019/9/20,5,Crosstalk vertical crosstalk,Vertical crosstalk ( ghosting ) is generated by the nonideal frequency response of the LCD and the image dependent frequency content of the column signal at low frequencies the necessary voltage to achieve a 50% transmission ( V50 ) decrease attributed to ionic effects in the LC layer the effective pixel voltage becomes high because the waveform is changed only slightly and the waveform distortion is small the pixel is dark crosstalk,2019/9/20,6,Crosstalk vertical crosstalk,Vertical crosstalk ( ghosting ) is generated by the nonideal frequency response of the LCD and the image dependent frequency content of the column signal at high frequencies the necessary V50 increases due to the low - pass filtering of the panel, caused by the ITO sheet resistance and the capacitance of the pixel and the frequence dependency of the effective pixel voltage becomes low because distorsion occurs in the column output waveform due to the driver and / or panel impedance the pixel is bright,2019/9/20,7,Reduction of Crosstalk,homogenize the frequency content of the column waveform improved driving schemes - IAP - MLA pattern dependent correction of the output voltage of the driver reduce space charge density reduce RC product of the whole panel ( cell gap ) low dV / df of the LC mixture sufficient e -o curve and selection of an optimum Vop,2019/9/20,8,STN 面板之dv/df特性,2019/9/20,9,Whats M signal(no M),Checkerboard waveform,All on/off waveform,2019/9/20,10,Whats M signal (M=1),在驅動波形中每(M+1)次就變換一次極性,Checkerboard waveform,All on/off waveform,2019/9/20,11,Whats M signal(032),032無設定M signal時COM waveform,032設定M=6al時COM waveform,2019/9/20,12,Whats M signal(032),032無設定M signal時A點合成waveform,032無設定M signal時B點合成waveform,2019/9/20,13,Whats M signal(032),032設定M=6時 A點合成waveform,032設定M=6時 B點合成waveform,2019/9/20,14,Whats M signal,How to