Design of poly-Si TFT-LCD panel with integrated driver circuits for an HDTV/XGA projection system

Abstract

Design techniques of 2.25-in. diagonal poly-Si TFT-LCD panel for an HDTV/XGA projection system are described, especially focusing on the driver circuits. The area-efficiency of the driver circuits is a very important design issue, because the integrated poly-Si driver circuits takes a very large area due to inferior device characteristics of single crystal-Si transistors. For area-efficiency, the pixel with a novel structure of the line memory has been proposed, and the analog switch circuits have been carefully designed in respect of area-efficiency without sacrificing the other performances. A novel gate driver architecture has been also proposed which can provide both progressive and dual-line scanning patterns for HDTV and XGA images. The gate drivers using tri-state buffers are established at both sides of the panel for redundancy, so that a defective one can be electrically separated from gate lines by a control signal instead of a conventional laser-cutting method. Area-efficiency is also discussed in designing the gate driver. Using the proposed design techniques, a 2.25-in. diagonal poly-Si TFT-LCD panel with source driver circuits of 1100 /spl mu/m-width and gate driver circuits of 2650 /spl mu/m-width for an HDTV/XGA projection system has been successfully developed.