LCD Through-Hole Taper Structure for Uniform Alignment Films
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Solution Overview
Problem
In high definition liquid crystal display devices, the increased taper angle of through holes in the organic passivation film leads to difficulties in aligning liquid crystal molecules, resulting in display defects such as light leakage and uneven brightness due to the surface tension preventing alignment film material from entering the through holes.
Innovation Solution
The through holes in the organic passivation film are designed with a smaller taper angle near the upper base and a larger taper angle near the lower base, allowing the alignment film material to easily enter and form a uniform layer, preventing display defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the taper angle of through holes is increased to reduce pixel size for high definition screens, then the pixel area is reduced, but the alignment film material cannot enter the through holes due to surface tension, causing display defects
Solution Approach 1:
The through hole is designed with different taper angles at different locations: a first taper angle in the lower portion and a second taper angle (smaller than the first) in the upper portion. This local variation in geometric properties allows the alignment film material to easily enter the through hole while maintaining structural integrity and achieving high definition display quality.
2Measurement precision
If the through hole diameter is reduced for high definition screens, then the pixel density increases, but the bonding strength between organic passivation film and interlayer insulating film is reduced, causing film removal
Solution Approach 1:
The through hole structure employs different taper angles at different heights to locally optimize both pixel density and bonding strength. The varied geometric configuration maintains sufficient bonding area and strength while achieving the required high pixel density for definition screens.
3Area of moving object
If the taper angle is increased to reduce through hole diameter, then the pixel area is reduced, but the alignment film material is prevented from entering due to surface tension, resulting in light leakage and uneven brightness
Solution Approach 1:
The through hole is configured with a first taper angle in the lower portion and a second taper angle (smaller than the first) in the upper portion. This local differentiation in geometric properties facilitates easy entry of alignment film material into the through hole while maintaining reduced pixel area, thereby preventing display defects such as light leakage and uneven brightness.
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 configuration ensures stable formation of the alignment film within the through holes, preventing display defects like light leakage and uneven brightness, while maintaining high transmittance and image quality in high definition screens.
Implementation Method 1
allowing the alignment film material to easily enter and form a uniform layer, preventing display defects
Data Source
AI summary
In a liquid crystal display device, a common electrode is formed on an organic passivation film, an interlayer insulating film is formed on the common electrode, a pixel electrode with a slit is formed on the interlayer insulating film, and a through hole is formed in the organic passivation film and the interlayer insulating film, so that the pixel electrode is connected to a source electrode of a TFT through the through hole. Further, the taper angle around the upper base of the through hole is smaller than the taper angle around the lower base. Thus, the alignment film material can easily flow into the through hole when the diameter of the through hole is reduced to connect the pixel and source electrodes, preventing display defects such as uneven brightness due to the absence of the alignment film or due to the alignment film irregularity around the through hole.