TFT Layout for Flat Panel Displays Using Inkjet Printing
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Solution Overview
Problem
The inkjet method for forming organic semiconductor layers in flat panel displays often results in nonuniform thicknesses of TFTs due to bouncing droplets, which is exacerbated in high-precision displays with closely integrated pixels, leading to inconsistent pixel and TFT performance.
Innovation Solution
The design includes a specific layout where the distance between adjacent TFTs is greater than the pixel width, with TFTs positioned in alternating regions of adjacent pixels, and additional gate lines or branch gate lines are used to connect TFTs, ensuring uniformity and preventing organic semiconductor solution from entering adjacent pixel banks during the inkjet process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inkjet method is used to form organic semiconductor layers, then manufacturing cost is reduced and manufacturing process is simplified, but manufacturing precision deteriorates due to nonuniform thickness caused by bouncing droplets
Solution Approach 1:
The patent applies local quality by positioning TFTs at specific locations within pixels (corner regions) rather than uniformly distributing them. This localized positioning strategy ensures that the inkjet-deposited organic semiconductor material lands precisely on intended targets, avoiding bouncing droplets from affecting adjacent pixels, thereby maintaining thickness uniformity while preserving the simplicity of the inkjet manufacturing process
Solution Approach 2:
The patent implements preliminary action by carefully pre-positioning TFTs in corner regions of pixels before the inkjet deposition process. This advance positioning creates sufficient spacing and geometric constraints that prevent bouncing droplets from entering adjacent pixel banks, ensuring uniform thickness distribution is achieved before any deposition occurs
2Productivity
If pixels are highly integrated to increase productivity, then output per unit area is improved, but manufacturing precision deteriorates due to increased difficulty in controlling the inkjet process
Solution Approach 1:
The patent applies local quality by confining TFTs to corner regions within each pixel, creating a localized deposition target that reduces the effective deposition area. This allows for higher pixel integration density while maintaining adequate spacing between adjacent TFTs, thereby preventing bouncing droplet interference even in highly integrated displays
Solution Approach 2:
The patent utilizes dimensional strategy by positioning TFTs in corner regions, effectively using the two-dimensional pixel space more efficiently. This corner placement creates diagonal spacing between adjacent TFTs in neighboring pixels, increasing the distance that bouncing droplets must travel to reach adjacent pixels, thus maintaining manufacturing precision at high integration densities
Data Source
AI summary
A flat panel display includes a plurality of gate lines; a plurality of data lines insulated with the gate lines, the data lines defining a pixel by intersecting the gate line; and a thin film transistor (TFT) being provided in each of the pixels and containing an organic semiconductor layer, wherein a distance between the adjacent TFTs in a direction extended to the gate line is longer than a width of the pixel in a direction extended to the gate line.