Segmented Pixel Electrode Laser Repair for IPS LCD Yield
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Solution Overview
Problem
The challenge in liquid crystal display devices is the difficulty in increasing fabrication yield due to pixel defects caused by conductive foreign substances entering between the pixel electrode and the common electrode, leading to short circuits and reduced manufacturing efficiency.
Innovation Solution
The solution involves dividing the pixel electrode into segments, allowing for disconnection from the source electrode using laser radiation, ensuring that even if one segment is shorted by a conductive foreign substance, the other segments can remain operational, thus preventing full pixel defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pixel electrode is formed as a single continuous structure, then the manufacturing process is simpler, but conductive foreign substances can cause complete pixel failure
Solution Approach 1:
The pixel electrode is divided into multiple independent segments (first pixel electrode segment and second pixel electrode segment) instead of forming a single continuous structure. This segmentation allows the pixel to maintain partial functionality even when conductive foreign substances cause short circuits in one segment, thereby improving reliability while managing structural complexity
Solution Approach 2:
Different segments of the pixel electrode are positioned at different locations (first segment at first location, second segment at second location) with different insulating films (first gate insulating film and second gate insulating film) formed at different times. This local differentiation ensures that defects in one location do not propagate to the entire pixel, maintaining local functionality and overall pixel reliability
2Productivity
If conductive foreign substances enter between pixel electrode and common electrode, then short circuits occur reducing fabrication yield, but implementing preventive measures increases manufacturing complexity
Solution Approach 1:
The first gate insulating film is formed before the pixel electrode, and the second gate insulating film is formed after the pixel electrode in a separate subsequent process. This preliminary and staged formation of insulating films creates multiple protective barriers against conductive foreign substances before they can cause complete pixel failure, thereby improving fabrication yield through preventive measures
Solution Approach 2:
Multiple gate insulating films are formed at different stages to provide protective cushioning against conductive foreign substances. The first gate insulating film provides initial protection, and the second gate insulating film provides additional protection in the subsequent process, creating a buffer that prevents complete pixel failure and maintains fabrication yield
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
This approach effectively increases the fabrication yield of liquid crystal display devices by maintaining pixel functionality despite the presence of conductive foreign substances, reducing the likelihood of pixel defects and enhancing manufacturing efficiency.
Implementation Method 1
the conducted segment of the pixel electrode is disconnected from the source electrode by applying laser radiation
Data Source
AI summary
The present invention seeks to decrease the number of pixel defects in an IPS liquid crystal display device. A gate electrode is formed on a TFT substrate, while a gate insulating film is overlaid on the gate electrode. A pixel electrode which is divided into segments is formed on the gate insulating film. The segments of the pixel electrode are normally interconnected by a source electrode. An inter-layer insulating film, on which a common electrode including slits is formed, is overlaid on the pixel electrode. In a case where the common electrode and one of the segments of the pixel electrode are conductively interconnected by a conductive foreign substance, the other segments of the pixel electrode are allowed to operate by disconnecting the conducted segment of the pixel electrode from the source electrode. Thus, one pixel is prevented from lapsing into a full pixel defect.