Transflective Display Panel Polymer Network Alignment
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Solution Overview
Problem
Transflecting liquid crystal display devices face issues with dark state leakage and complex manufacturing processes, particularly in achieving the same display effect in both transmission and reflection regions with single-cell-thickness liquid crystal layers.
Innovation Solution
A display panel design featuring a liquid crystal layer with nematic liquid crystals and polymerizable monomers in both transmission and reflection regions, where the polymer network in the reflection region assists in aligning the liquid crystals differently, and the alignment direction in the transmission region matches the alignment layer, eliminating the need for additional retarders and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-cell-thickness liquid crystal layer is used in both transmission and reflection regions, then the manufacturing complexity is reduced, but dark state light leakage occurs and contrast is reduced
Solution Approach 1:
The patent applies different liquid crystal alignment configurations to different regions of the display panel. Specifically, the reflection region uses a special alignment angle (10-20 degrees relative to the alignment layer) while the transmission region uses conventional alignment, allowing each region to optimize its performance for its specific function while using a uniform cell thickness
Solution Approach 2:
The patent changes the alignment angle parameter of the liquid crystal molecules in the reflection region to achieve proper optical performance. By adjusting the alignment angle to 10-20 degrees relative to the alignment layer, the reflection region achieves the necessary optical path difference without requiring additional retarder layers, thus maintaining single-cell-thickness while improving display quality
2Reliability
If the initial alignment direction of nematic liquid crystal in reflection regions is adjusted to form an angle with the electrodes, then the display effect is improved, but dark state light leakage and reduced contrast occur
Solution Approach 1:
The patent optimizes the alignment angle parameter to a specific range (10-20 degrees) rather than using conventional angles. This specific angle range creates the necessary optical path difference for reflection mode operation while minimizing light leakage in the dark state, thereby improving display contrast and eliminating the harmful effect of light leakage
Solution Approach 2:
The patent utilizes the dynamic response of liquid crystal molecules to electric fields in combination with the special alignment angle. When voltage is applied, the liquid crystal molecules reorient to achieve the desired optical effect for reflection, while in the off-state, the special alignment configuration ensures minimal light leakage, creating dynamic control over light transmission and reflection
3Reliability
If an additional 1/4 wave plate is added in the reflection region, then dark state light leakage is reduced, but the manufacturing process becomes complex
Solution Approach 1:
The patent extracts the wave plate function from a separate optical component and integrates it into the liquid crystal layer itself through special alignment configuration. By using the liquid crystal molecules' inherent birefringence properties combined with the 10-20 degree alignment angle, the system achieves the optical path difference effect of a wave plate without adding physical wave plate layers, thus reducing manufacturing complexity while maintaining dark state performance
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 solution reduces dark state leakage, enhances contrast, and simplifies the manufacturing process while maintaining sharp boundaries between transmission and reflection regions with wide viewing angles and matching display curves.
Implementation Method 1
The liquid crystal layer in the reflection region includes nematic liquid crystal and a polymer network. The liquid crystal layer in the transmission region includes a liquid crystal mixture including the nematic liquid crystal and polymerizable monomers. The polymer network in the reflection region is formed by polymerizing the polymerizable monomers in the liquid crystal mixture.
Implementation Method 2
In case of no electric field, an alignment direction of the nematic liquid crystal in the reflection region is different from that of the first alignment layer, and an alignment direction of the nematic liquid crystal in the transmission region is same as that of the first alignment layer.
Data Source
AI summary
A display panel and a manufacturing method thereof are provided. Each pixel of the display panel includes a transmission region and a reflection region, and the display panel includes a first polarizer, a first base substrate, a first alignment layer, a liquid crystal layer, a second alignment layer, a second base substrate, and a second polarizer. A reflection layer is provided between the second alignment layer and the second polarizer in the reflection region. The liquid crystal layer in the reflection region includes nematic liquid crystal and a polymer network. The liquid crystal layer in the transmission region includes a liquid crystal mixture including the nematic liquid crystal and polymerizable monomers. The polymer network in reflection region is formed by polymerizing the polymerizable monomers in the liquid crystal mixture.