LCD Asymmetric Alignment Layers for Misalignment Tolerance
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Solution Overview
Problem
In liquid crystal displays, misalignment of substrates during initial alignment of liquid crystal molecules can lead to irregular pretilt directions at domain boundaries, deteriorating display quality.
Innovation Solution
A liquid crystal display with a first alignment layer having larger photo-polymerization protrusions than a second alignment layer, and including ultraviolet light absorption particles, is manufactured with a curvature where the axis of curvature is parallel to the gate and data lines, preventing irregular pretilt directions when substrates are misaligned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If substrates are misaligned during initial alignment of liquid crystal molecules, then manufacturing simplicity is maintained, but display quality deteriorates due to irregular pretilt directions at domain boundaries
Solution Approach 1:
The patent changes the physical-chemical parameters of the alignment layer by introducing photo-polymerization protrusions with specific density and size characteristics. The first alignment layer has photo-polymerization protrusions with higher density and larger size compared to the second alignment layer, creating asymmetric alignment characteristics that compensate for substrate misalignment and maintain consistent pretilt directions at domain boundaries
Solution Approach 2:
The patent applies different properties to different regions of the alignment layers. The first alignment layer is designed with specific photo-polymerization protrusion characteristics (higher density, larger size) while the second alignment layer has different characteristics (lower density, smaller size). This local differentiation allows the system to tolerate substrate misalignment while maintaining overall display quality
2Manufacturing precision
If asymmetric photo-polymerization protrusions are created in alignment layers, then pretilt direction consistency is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-forming photo-polymerization protrusions in the alignment layers before liquid crystal molecule alignment. The asymmetric protrusion structure is prepared in advance, and upon light irradiation, it automatically generates the desired pretilt directions without requiring precise substrate alignment during the alignment process
Solution Approach 2:
The patent replaces the mechanical precision requirement (substrate alignment) with a photochemical mechanism (light-induced polymerization of asymmetric protrusions). Instead of relying on precise mechanical positioning of substrates, the system uses light irradiation to activate the photo-polymerization process, which inherently creates the correct pretilt directions through the asymmetric protrusion structure
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 prevents deterioration of display quality by ensuring consistent liquid crystal molecule alignment even when substrates are misaligned, maintaining image quality across domain boundaries.
Implementation Method 1
the liquid crystal layer may include ultraviolet (UV) light absorption particles
Implementation Method 2
a method for pretilting liquid crystal molecules by using prepolymers, which may be polymerized by light such as ultraviolet light
Data Source
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AI summary
A liquid crystal display (LCD) includes a first substrate, a gate line and a data line disposed on the first substrate, a pixel electrode connected to the gate line and the data line, a first alignment layer disposed on the pixel electrode, a second substrate opposite to the first substrate, a common electrode disposed on the second substrate, and a second alignment layer disposed on the common electrode, in which a thickness of the first alignment layer is greater than a thickness of the second alignment layer.