TFT LCD 驱动原理与系统.ppt

TFT LCD 驅動原理與系統 液晶及液晶顯示器簡介 TFT LCD 驅動原理 影響TFT LCD 畫面品質的因素 TFT LCD Driver IC LCD 數位界面簡介 背光板簡介 未來趨勢與走向 被動式/主動矩陣式液晶顯示器Passive/Active Matrix LCD The Color Pixel of TFT LCD Arrangement of Color Filter Aperture Ratio TFT LCD 驅動 Timing Chart of TFT LCDS TFTL LCDS Driving Method Direct Driving of TFT LCDs Vcom Ac ModulationAddressing of TFT LCDs Direct Driving Vs Vcom Modulation 影響 LCD 畫面品質的因素 Horizontal Crosstalk Vertical Crosstalk Shading Crosstalk 液晶電容的效應 液晶電容CLC會隨液晶作用電壓的改變而變化，因此在驅動液晶時會有殘存的DC成份，其所造成的影響 Image Sticking. Picture Flicker. 液晶作用電壓大時，液晶分子趨向平行電場方向排列 液晶作用電場小時，液晶分子趨向垂直電場方向排列 Horizontal Line Crosstalk Horizontal Area Crosstalk TFT LCD Driver IC Scan (gate, row) driver Data (source, column) driver High voltage, mixed mode Usually TCP package Vendors：TI Japan, sharp, NEC, Toshiba, Matsushita, Hitachi, Samsung, LG, vivid, Winbond (cirrus logic, vivid), Mosel(sharp)… Maybe in the future, driver IC is not necessary in Large size LCD The Block Diagram of the TFT LCD Module Video Signal Timing Spec. TFT-LCD Module Video Signal Timing Spec. Resolution Vs Outputs - 1 Resolution Vs Fmax Data Driver Key Specifications Channel number Gray Scale (6bits, 8bit… ) Max Operation Freq. (45MHz, 55MHz,65MHz… ) Pixel Charging Time (eg. R=2K,C=20pF,6.5 μs90%, 11.5 μs 100%) Line or column/dot inversion Output voltage deviation (±10mV,±5mV,±3mV…) Operation voltage Digital：5V, 3.3V, 2.5V Analog：10V ~ 15V Others(data inversion, low-power mode, offset canceling, RSDS/LVDS input…etc) Driver IC Trend LCD數位界面簡介 類比PC界面簡介 LCD數位界面簡介 LVDS TMDS GVIF Analog Interface TFT LCD Module Digital Interface TFT LCD Module Digital Interface High image quality Long transmission distance Simple hardware High speed, EMI problem ADC/DAC not needed Transmitter/receiver needed Main technology LVDS, TMDS, GVIF Standard OpenLDI, DFP, DVI, DISM,….. The Digital Interface --LVDS LVDS interface (TI, NS, Thine) Low voltage differential signaling Mainstream in the notebook PC now(close system) 7x in