Liquid Crystal Display Light Shielding Position Control
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Solution Overview
Problem
In COA liquid crystal display devices, the thickness difference between the black matrix on the upper substrate and the color filter on the lower substrate leads to liquid crystal tilt, causing light leakage and decreased contrast, which is typically addressed by adding an overcoat layer, increasing manufacturing costs and reliability risks.
Innovation Solution
The position of the light shielding portion is controlled such that its projection area on the second substrate is within the electrode portions, effectively covering the tilted liquid crystals and reducing light leakage without the need for an overcoat layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an overcoat layer is provided to cover the black matrix layer, then light leakage is reduced, but manufacturing cost and reliability risk increase
Solution Approach 1:
The invention extracts and eliminates the overcoat layer from the display device structure. Instead of adding an overcoat layer to cover the black matrix layer, the patent positions the light shielding portion's projection area within the electrode portions, allowing the electrode layers to directly cover the tilted liquid crystals at the edges without requiring an additional overcoat layer, thereby reducing manufacturing steps and reliability risks
Solution Approach 2:
The invention uses the electrode layers (first electrode portion and second electrode portion) as intermediaries to cover the tilted liquid crystals at the edges of the light shielding portion. By positioning the light shielding portion's projection area within the electrode portions, the electrode layers serve as the covering structure that prevents light leakage, replacing the traditional overcoat layer function
2Stability of the object's composition
If the black matrix layer thickness is increased to match the color filter layer, then liquid crystal alignment is improved, but the device structure becomes more complex
Solution Approach 1:
The invention applies local quality by creating a specific positional relationship between the light shielding portion and electrode portions. The projection area of the light shielding portion is positioned within the electrode portions, ensuring that the tilted liquid crystals at the edges are locally covered by the electrode layers, rather than requiring a global structural modification like increasing black matrix layer thickness
Data Source
AI summary
A liquid crystal display device includes a first substrate, a second substrate disposed opposite to the first substrate, a gate line disposed on the second substrate, an electrode layer disposed on the second substrate, and a light shielding portion disposed at a side of the first substrate facing the second substrate. The electrode layer includes a first electrode portion and a second electrode portion. The gate line is disposed between the first electrode portion and the second electrode portion. A projection area of the light shielding portion projected on the second substrate is overlapped with the gate line, and the projection area has a first side and a second side. The first electrode portion has a third side and a fourth side. The third side is disposed away from the gate line, and the first side is disposed between the third side and the fourth side.