A 6.7-in Square High-Resolution Full-Color TFT-LCD

Abstract

A 6.7-in. square, full-color, a-Si TFT-LCD with 1, 024 × 1, 024 dots and 153 lines-per-in. resolution has been developed. TFT-LCDs with such large display area and high-resolution have several problems : a decreased scan period, an increased scan-line time-constant, and so on. An advanced scanning method in which contiguous scan pulses overlap each other was adopted for the TFT-LCD. Using this driving method, the TFT channel width is reduced. As a result, the scan line capacitance of TFT-LCD has been reduced to 4/5. Moreover, the scan line has low resistance. This line consists of a straight Mo-Ta alloy main and Al islands. Each Al island is connected with the main line through a via hole in a gate insulator layer. With this structure, scan line resistance has been reduced to 1/2. Using these methods, TFT-LCD has good uniformity and gray scale reproduction over a large display area with high resolution.