Active Matrix Substrate Repair via Laser Isolation and Through-Hole Connection
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Solution Overview
Problem
Active matrix substrates for display devices often suffer from short-circuited pixels due to defects, leading to bright-spot pixels that deteriorate display quality, and conventional repair methods either fail to route common lines effectively or decrease the aperture ratio.
Innovation Solution
A method for producing active matrix substrates that involves forming thin-film transistor elements, insulating films, and common electrodes, detecting short-circuited pixels, removing the pixel electrode inside the contact hole using laser irradiation, and creating a through hole to connect the pixel and common electrodes, thereby isolating the drain electrode without reducing the aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common line for repair is routed into the pixel to connect the common electrode to the drain electrode, then the short-circuited pixel can be repaired, but the aperture ratio of the pixel decreases
Solution Approach 1:
The patent extracts the common line routing operation from the pixel interior to the pixel exterior. By forming the through hole in the second insulating film outside the contact hole, the common line can be connected to the pixel electrode without penetrating through the pixel interior, thereby avoiding aperture ratio reduction while still achieving the repair function of connecting the common electrode to the drain electrode
Solution Approach 2:
The patent changes the spatial dimension of the repair approach by moving from a planar routing within the pixel to a vertical through-hole connection outside the pixel. The through hole penetrates the second insulating film in a direction perpendicular to the substrate, allowing the common line to connect to the pixel electrode from the side rather than through the pixel interior, thus preserving the aperture ratio
2Reliability
If the pixel electrode is removed inside the contact hole to isolate it from the drain electrode, then the short circuit is eliminated, but the structural integrity of the pixel electrode may be compromised
Solution Approach 1:
The patent applies local quality by selectively removing the pixel electrode material only in the specific region inside the contact hole where the short circuit occurs, while preserving the pixel electrode structure in all other regions. This localized removal eliminates the short circuit between the pixel electrode and drain electrode while maintaining the overall structural integrity and functionality of the pixel electrode
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective repair of short-circuited pixels without decreasing the aperture ratio, improving display quality by converting bright-spot pixels into black-spot pixels without the need for routing a common line, thus enhancing production efficiency and maintaining high-definition display capabilities.
Implementation Method 1
removing the pixel electrode inside the contact hole in the short-circuited pixel... The step (C) includes removing the pixel electrode by laser beam irradiation
Implementation Method 2
forming a through hole that penetrates the second insulating film... The step (D) includes melt-connecting the pixel electrode and the common electrode while forming the through hole by laser beam irradiation
Data Source
AI summary
A method for producing an active matrix substrate includes the steps of: (A) forming in individual pixels a thin-film transistor element, a first insulating film, a pixel electrode to be connected to a drain electrode of the thin-film transistor element through a contact hole formed at least in the first insulating film, a second insulating film, and a common electrode to be superposed on the pixel electrode outside the contact hole, with the second insulating film in between; (B) detecting a short-circuited pixel among the pixels; (C) removing the pixel electrode inside the contact hole in the short-circuited pixel and thereby isolating the pixel electrode from the drain electrode; and (D) forming a through hole that penetrates the second insulating film outside the contact hole in the short-circuited pixel, and connecting the pixel electrode and the common electrode to each other through the through hole.