Parallelogram Slit Pixel Electrode with Arcuate Recesses for LCD
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Solution Overview
Problem
In liquid crystal display devices using a transverse electric field driving mode, non-uniform electric fields near the slits of the pixel electrode lead to alignment defects of liquid crystal molecules, resulting in reduced transmittance and inadequate luminance, especially when displaying a white screen.
Innovation Solution
The pixel electrode is designed with slits of a substantially parallelogrammatic shape, featuring arcuate recess portions at the corner portions with acute interior angles, which reduces non-uniformity of electric fields and suppresses alignment defects, thereby improving transmittance and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pixel electrode is designed with straight-edged slits, then the manufacturing process is simple, but non-uniform electric fields occur at the corner portions causing alignment defects of liquid crystal molecules
Solution Approach 1:
The patent applies curvature by replacing the sharp corner portions of the slit with arcuate recess portions. This curvature modification eliminates the non-uniform electric field concentration that occurs at sharp corners, thereby preventing alignment defects of liquid crystal molecules while maintaining manufacturing feasibility through standard photolithography processes.
2Area of moving object
If the slit has acute corner portions, then the area of the pixel electrode is maximized, but alignment defects occur reducing transmittance and luminance
Solution Approach 1:
By introducing arcuate recess portions at the corner portions of the slit, the patent maintains most of the pixel electrode area while eliminating the harmful electric field concentration at sharp corners. This curvature modification prevents alignment defects that would otherwise reduce transmittance and luminance, thus resolving the contradiction between area maximization and display quality.
3Device complexity
If the slit edges are straight and sharp, then the photomask pattern is simple, but electric field non-uniformity causes dark lines in the display
Solution Approach 1:
The arcuate recess portions are designed with radii and dimensions that can be directly implemented using standard photomask fabrication techniques. This curvature modification eliminates electric field non-uniformity and the resulting dark lines in display, while adding only minimal complexity to the photomask pattern that remains within manufacturing capabilities.
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
The design enhances transmittance and achieves good display quality with high luminance during white screen display by minimizing alignment defects and maintaining uniform electric field directions, particularly at the corner portions of the slits.
Implementation Method 1
the directions of electric fields are not uniform in the vicinity of both end portions of the slit. Hence, in the vicinity of both end portions of the slit, the directions of alignment of liquid crystal molecules, which are driven by electric fields in non-uniform directions, also become non-uniform.
Implementation Method 2
the directions of alignment of liquid crystal molecules, which are driven by electric fields in non-uniform directions, also become non-uniform
Data Source
AI summary
A liquid crystal display device includes a liquid crystal display panel which is configured to hold a liquid crystal layer between an array substrate and a counter-substrate. The array substrate includes a pixel electrode which is connected to a switching element, and a counter-electrode which is opposed to the pixel electrode via an interlayer insulation film. The pixel electrode includes a plurality of slits. The slit is formed in a substantially parallelogrammatic shape, and includes, at a corner portion with an acute interior angle, an arcuate recess portion which is recessed toward an outside of an edge.