Peripheral Cell Gap Testing via Segmented Light Shielding
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Solution Overview
Problem
In thin film transistor liquid crystal displays (TFT-LCDs), the cell gap in the peripheral area is not uniform due to film thickness, photo spacer, and sealant mismatch, leading to display failures like yellowish or blueish periphery issues, with no effective method to analyze cell gap distribution in this area.
Innovation Solution
A display panel design with a light shielding layer in the peripheral area featuring multiple opening areas with light transmissive layers, allowing for cell gap distribution testing using a cell gap test device, and a laser repair method to ensure proper shielding, enabling uniform cell gap achievement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a continuous light shielding layer is provided in the peripheral area, then light leakage is prevented, but cell gap testing becomes impossible in the peripheral area
Solution Approach 1:
The continuous light shielding layer in the peripheral area is segmented into multiple discrete light shielding portions arranged at intervals. This segmentation creates gaps between the light shielding portions, allowing light to pass through to the liquid crystal layer and enable optical testing of cell gap in the peripheral area, while still providing sufficient light shielding to prevent light leakage.
2Object-affected harmful factors
If the light shielding layer is made thick to ensure shielding effectiveness, then light leakage is prevented, but the structure becomes complex and manufacturing difficult
Solution Approach 1:
Different regions of the light shielding layer are given different optical properties. The light shielding portions in the peripheral area have optimized thickness and material properties to provide sufficient light shielding while maintaining transparency to the testing wavelength, eliminating the need for uniform thick shielding throughout.
Solution Approach 2:
The light shielding layer uses composite materials or multi-layer structures that combine light shielding functionality with optical transparency at specific wavelengths. This allows the layer to simultaneously prevent light leakage and permit optical testing through the peripheral area.
3Measurement precision
If conventional testing methods are used, then cell gap can be tested in the display area, but peripheral area cell gap remains unanalyzable
Solution Approach 1:
The modified light shielding layer structure serves multiple functions: it continues to prevent light leakage in the peripheral area while simultaneously enabling optical testing of cell gap in the same region. This universal design allows a single structure to fulfill both shielding and testing requirements, extending testing capability from only the display area to include the peripheral area.
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
Effectively determines and achieves uniform cell gap distribution in the peripheral area, preventing display failures and reducing material waste by identifying and compensating non-uniformities, thus enhancing manufacturing efficiency and product quality.
Implementation Method 1
each opening area being provided with a light transmissive layer
Implementation Method 2
The cell gap distribution can be in correspondence with the yellowish (or blueish) degree of the peripheral
Data Source
AI summary
A display panel, a method for testing a cell gap thereof, and a display device are disclosed. The display panel includes a first substrate and a second substrate arranged opposite to each other, wherein a light shielding layer is provided on a side of the first substrate close to the second substrate, a portion of the light shielding layer located in a peripheral region includes a plurality of opening areas arranged at intervals, each opening area being provided with a light transmissive layer; and wherein the second substrate has a light transmissive area, an orthographic projection of the light transmissive layer on the second substrate at least partly overlaps with the light transmissive area on the second substrate.