PSVA Liquid Crystal Alignment via Photopolymerization
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Solution Overview
Problem
PSVA liquid crystal display panels face issues with low aperture ratio and color shift at large viewing angles due to gamma curve deviations, which are exacerbated by increased complexity and drive difficulty from sub-pixel circuit designs.
Innovation Solution
An alignment method for PSVA liquid crystal display panels involves doping the liquid crystal layer with photopolymerizable monomers and using a semi-transparent mask with areas of different transmittance to apply alternating voltage and ultraviolet light, allowing the monomers to polymerize and form granular polymers, resulting in liquid crystal molecules tilting at different angles, thereby reducing color shift and maintaining a high aperture ratio without additional circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sub-pixel circuit design is used to attenuate color shift at large viewing angles, then color shift is reduced, but aperture ratio decreases and drive difficulty increases
Solution Approach 1:
The patent replaces the electrical/circuit-based solution (additional gate lines, data lines, and thin film transistors) with a photochemical alignment method. By using photopolymerizable monomers that polymerize under UV light to form granular projections, the alignment structure is created through chemical transformation rather than electrical circuit design, thereby eliminating the need for additional driving circuits and reducing device complexity.
Solution Approach 2:
The patent changes the physical-chemical parameters of the liquid crystal system by introducing photopolymerizable monomers with specific photopolymerization characteristics. These monomers undergo phase transformation from liquid to solid polymer structure when exposed to UV light, creating alignment structures with controlled pretilt angles. This parameter change enables alignment control without additional circuitry, resolving the contradiction between color shift correction and device complexity.
2Object-affected harmful factors
If sub-pixel circuit design is used to attenuate color shift at large viewing angles, then color shift is reduced, but aperture ratio decreases
Solution Approach 1:
The patent substitutes the mechanical/electrical approach of adding more circuit elements (which occupy physical space and reduce aperture ratio) with a photochemical approach. The photopolymerizable monomers are dissolved in the liquid crystal material itself, and upon UV irradiation, they form alignment structures in-situ within the liquid crystal layer, requiring no additional physical components that would reduce the aperture ratio.
Solution Approach 2:
The patent creates a composite liquid crystal material system by doping the liquid crystal with photopolymerizable monomers. This composite material combines the optical properties of liquid crystal with the photo-responsive properties of the monomers, enabling the liquid crystal layer itself to form alignment structures through photopolymerization. This eliminates the need for separate alignment layers or additional circuit elements, thereby maintaining high aperture ratio while correcting color shift.
3Area of stationary object
If photopolymerizable monomers are used to form alignment structures, then aperture ratio is maintained high, but additional light treatment process is required
Solution Approach 1:
The patent merges the alignment layer function with the liquid crystal material function by incorporating photopolymerizable monomers directly into the liquid crystal composition. This eliminates the need for separate alignment layers and their associated coating and curing processes. The single liquid crystal layer serves both as the display medium and as the alignment structure-forming material, simplifying the overall manufacturing process despite the addition of UV treatment.
Solution Approach 2:
The photopolymerizable monomers act as intermediaries that bridge the gap between liquid crystal molecules and UV light. When UV light irradiates the liquid crystal layer, the monomers absorb the energy and undergo polymerization, forming granular projections that serve as alignment structures. This intermediary mechanism enables alignment structure formation through a single UV treatment step without requiring complex multi-step processes, balancing manufacturing simplicity with effective alignment control.
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 method effectively reduces color shift at large viewing angles and maintains a high aperture ratio for PSVA liquid crystal display panels by creating alignment areas with different pretilt angles, eliminating the need for additional gate lines, data lines, and thin film transistors.
Implementation Method 1
using the semi-transparent mask to perform light treatment on the liquid crystal display panel, so as to allow the photopolymerizable monomers to polymerize on surfaces of the two substrates
Implementation Method 2
applying an alternating voltage to the liquid crystal display panel, so as to allow liquid crystal molecules and the photopolymerizable monomers in the liquid crystal layer to tilt along certain directions
Data Source
AI summary
Provided is an alignment method suitable for a PSVA liquid crystal display panel, This belongs to the field of display technologies, and can solve the technical problem of a low aperture ratio of an existing PSVA liquid crystal display panel.