Browse Prior Art Database

TFT Color Pixel Architecture

IP.com Disclosure Number: IPCOM000036050D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 3 page(s) / 30K

Publishing Venue

IBM

Related People

Alt, PM: AUTHOR [+2]

Abstract

We disclose a pel architecture for color TFT displays which combines a high image quality color mosaic arrangement with reduced problems from gate delay.

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TFT Color Pixel Architecture

We disclose a pel architecture for color TFT displays which combines a high image quality color mosaic arrangement with reduced problems from gate delay.

Thin film transistor/liquid crystal (TFT/LC) displays have a number of problems which prevent them from reaching the display market. One of the more pressing problems is called gate delay. The delay arises from the distributed series resistance and shunt capacitance necessarily associated with the metal line connecting the TFT gate terminals along a row in the display.

The above problem is coupled with the choice of the color mosaic pattern. Any color mosaic pattern which requires two gate lines to create the CRT equivalent pixel has only half the time available for the gate signal compared to a pattern requiring only one gate line. Because of the gate delay, a color pixel grouping associated with a single gate line is required. The simplest choice is an RGB sequence on a single gate line. This solution renders relatively poor images. Since the macro pixel wants to be square, the individual pixels must be rectangular and this would give different size horizontal & vertical lines in the monochrome mode.

We propose a pixel grouping whose geometry is that of the RGB triad with the brick tiling but with electrical contact to a single gate line. The proposed method of implementing this scheme is shown in the figure. The basic concept is to split the pixel pad, allowing the data lines to run between them from top to bottom. One TFT per pad pair is used, and all three pad pairs of the triad are connected to the gate line. The halves of the pixel pad are connected by a thin metal li...