Display Substrate Optical Compensation Layers for Light Leakage
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Solution Overview
Problem
Liquid crystal displays (LCDs) suffer from light leakage in the dark state, particularly in Advanced Super Dimension Switch (ADS) and In-Plane Switching (IPS) types, due to phase delay and birefringence effects, leading to unwanted light emission when no voltage is applied.
Innovation Solution
A display substrate is designed with a base, color filter layer, cover layers, optical compensation layers, and spacers to compensate for phase delay and maintain polarization, preventing light leakage. The substrate includes alignment layers and a black matrix to enhance light control, with specific materials and processes like plasma treatment to improve wettability and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If optical compensation layers are added to compensate phase delay, then light leakage in dark state is reduced, but device complexity increases
Solution Approach 1:
The optical compensation function is divided into multiple separate layers (first optical compensation layer, second optical compensation layer) with different orientations. Each layer compensates for phase delay in specific directions, and together they achieve comprehensive compensation. This segmentation allows the system to address light leakage effectively while maintaining manageable structural complexity through modular design.
Solution Approach 2:
Different regions of the display substrate are equipped with differently oriented optical compensation layers. The first optical compensation layer is oriented in a first direction while the second is oriented in a second direction perpendicular to the first. This local variation in optical properties allows precise compensation of phase delay in different areas, reducing light leakage specifically where needed without uniformly increasing complexity across the entire device.
2Manufacturing precision
If multiple optical compensation layers with different orientations are used, then phase delay compensation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The first optical compensation layer is formed on the color filter substrate before the liquid crystal layer is assembled, and the second optical compensation layer is formed after the liquid crystal layer is in place. This preliminary and sequential formation allows each layer to be precisely positioned and oriented during its respective formation stage, ensuring accurate phase delay compensation without requiring post-assembly realignment, thus maintaining high manufacturing precision while managing complexity.
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 solution effectively compensates for phase delay and maintains the desired polarization state, significantly reducing light leakage in dark states, even under external forces like squeezing, thereby enhancing the display's dark-state performance.
Implementation Method 1
each optical compensation layer is positioned on a side of the first cover layer away from the base and is configured to compensate a phase delay of light emitted from a liquid crystal layer
Implementation Method 2
performing a plasma process on a surface of the first cover layer
Data Source
AI summary
There are provided a display substrate, a method for manufacturing a display substrate, and a liquid crystal display panel, the display substrate includes: a color filter layer disposed on a base; at least one cover layer positioned on a side of the color filter layer away from the base and including a first cover layer which is in contact with the color filter layer; at least one optical compensation layer, where each optical compensation layer is positioned on a side of the first cover layer away from the base and is configured to compensate a phase delay of light emitted from a liquid crystal layer of the liquid crystal display panel; and a spacer positioned on the side of the first cover layer away from the base and being in contact with one of the at least one cover layer.