Vertical Photo Alignment Method for LCD Panel Sub-Regions
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Solution Overview
Problem
Current liquid crystal display panel manufacturing methods face challenges with alignment precision and contamination issues in non-contact alignment techniques, particularly in achieving wide view angles and preventing color deviation, due to the complexity and precision loss in mask movement during sub-pixel alignment.
Innovation Solution
A vertical photo alignment method where each pixel region is divided into four sub-regions with different alignment directions, achieved by coating a photo alignment polymer on substrates and using a mask with transparent and opaque regions to direct linear UV light irradiation at specific angles, ensuring high precision and low cost through steady mask positioning and substrate rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mask movement is used to divide pixel regions into sub-regions for multi-directional alignment, then view angle and color deviation are improved, but alignment precision is reduced due to mask movement errors
Solution Approach 1:
Instead of moving the mask to different positions for irradiating different sub-regions, the invention inverts the approach by keeping the mask stationary and rotating the substrate to bring different sub-regions under the fixed mask. This inversion eliminates mask movement errors while achieving the same multi-directional alignment effect, thus resolving the contradiction between view angle adaptation and alignment precision.
Solution Approach 2:
The invention transitions from two-dimensional mask movement (moving mask in X-Y plane to cover different regions) to three-dimensional substrate rotation (rotating substrate around Z-axis while keeping mask fixed). This dimensional change allows multi-region irradiation without compromising mask positioning accuracy, thereby maintaining alignment precision while achieving wide view angle and color deviation compensation.
2Strength
If rubbing alignment is used to align liquid crystal molecules, then alignment ability is improved, but contamination from electrostatic and particles increases
Solution Approach 1:
The invention replaces the mechanical rubbing system (fabric roller physically contacting and frictioning the alignment layer) with a photo-induced alignment system (UV light irradiating the alignment layer through a mask). This substitution eliminates mechanical contact that generates electrostatic and particle contamination, while still achieving strong alignment ability through photopolymerization of the alignment layer, thus resolving the contradiction between alignment strength and contamination prevention.
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 method enhances alignment precision, resulting in liquid crystal display panels with wide view angles, high transmission rates, no color deviation, high contrast, and high resolution by maintaining mask stability and achieving perpendicular alignment directions on corresponding sub-regions of CF and TFT substrates.
Implementation Method 1
The photo alignment agent is a kind of Polymer, which is consisted of many monomer small molecule bonds. By baking or irradiating thereto, the monomers are bonded with one another to form the macromolecules.
Implementation Method 2
The photo alignment is to use the linearly polarized UV light to irradiate on the polymer alignment film having photosensitizer to make the polymer possess the alignment ability.
Data Source
AI summary
In a provided vertical alignment method, a pixel region, and the pixel region is divided into four sub regions of equal sizes which each is designed to be a square, and a pattern unit on the mask comprises a photic region corresponding to one sub region and a shading region corresponding to the other three sub regions in shape and size. The mask is employed to implement linear UV light irradiation to one sub region according to a certain irradiation angle to obtain a alignment direction of the one sub region, and then, the position of the mask and the certain irradiation angle of the irradiation are maintained to be unchanged. By rotating the pixel region 90° with three times, and the irradiation is implemented to the other three sub regions. Accordingly, the four sub regions have four alignment directions different from one another.