A 2.7 in. 1.3 MPixel driver-integrated poly-Si TFT-LCD for multimedia projectors

The rapid progress of multimedia demands liquid crystal display (LCD) projectors that can display computer data, such as video-graphic arrays (VGA), super-video-graphic arrays (SVGA), extended-graphic arrays (XGA) and super-extended-graphic arrays (SXGA). One of the major challenges for poly-Si TFT drivers in such multi-scan LCDs is displaying as black in the peripheral region around the picture during a blanking period. Using conventional shift register driver circuits, the scanning speed in the up-and-down no-picture region is too high for pixel TFTs to write signals for black. Although decoder driver circuits for multi-scan operation have been introduced into an HDTV poly-Si TFT-LCD, they require many address signals and logic gates. These increase circuit area and thereby decrease the manufacturing yields. Poly-Si TFT drivers use a combination of bi-directional shift registers and decoder circuits to solve the above problems for a 2.7 in, 1.3 Mpixel TFT LCD light valve.