2-Transistor, 1.5-Gate Redundancy Technology for Color TFT-LCDs

Tadamichi KAWADA  Hideki NAKAJIMA  Shigeto KOHDA  Shigenobu SAKAI  

IEICE TRANSACTIONS on Electronics   Vol.E79-C   No.8   pp.1083-1090
Publication Date: 1996/08/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Liquid-Crystal Displays)
TFT-LCD,  duplication redundancy,  automatic defect tolerance,  active matrix,  

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This paper proposes a new duplication redundancy technology, 2 Transistors for 1.5 Gates, that is capable of automatic defect tolerance, so making large, high-resolution, color TFT-LCD panel fabrication both easy and economical. This redundancy technology with automatic defect tolerant capability has a low hardware overhead and is very capable of compensating for open circuit defects in a large active-matrix panel. This technology was confirmed by fabricating a 9.5-inch color TFT-LCD panel with 640480 pixels(960960 dots). This panel showed excellent display performance and produced pictures without defects. The yield improvement effect of this technology was also confirmed by calculation based on the Boltzmann statistics model. Consequently, this technology is clearly seen to have a yield improvement effect equal to defect density reduction of about one order, compared to non redundancy. This technology drastically reduces dot and line defects, enabling fabrication of large, high-resolution, color TFT-LCD panels at a relatively low cost.