LCD Panel Photo-Alignment Method for Contrast Improvement
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Solution Overview
Problem
Current LCD display panel manufacturing techniques face issues such as low aperture ratio, inferior contrast, and slow response speed due to mechanical rubbing processes, which result in un-uniform alignment and low yield, while photo-alignment techniques are sensitive to ultraviolet light and have limitations in controlling liquid crystal molecule alignment.
Innovation Solution
The method involves applying perpendicular electrical fields and photo-alignment using ultraviolet light to improve the preset angles of liquid crystal molecules in both vertical and lateral directions, enhancing contrast by using strip-shaped electrodes and varying electrical field strengths and illumination angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical rubbing process is used for alignment, then the process can be conducted under normal temperature with short rubbing time and high productivity, but the alignment becomes un-uniform due to deterioration during storage or transportation, particles, residual static electricity, and brush marks
Solution Approach 1:
The patent replaces the mechanical rubbing system with a photo-alignment system using ultraviolet light and polyimide alignment films. The alignment is achieved through light-induced molecular orientation rather than mechanical contact, eliminating brush marks, static electricity issues, and particle contamination while maintaining high productivity and uniform alignment quality.
Solution Approach 2:
The patent changes the alignment mechanism from mechanical force to optical field interaction. By controlling the polarization direction and intensity of ultraviolet light, precise alignment angles can be achieved without the defects associated with mechanical rubbing, thereby improving both uniformity and productivity.
2Manufacturing precision
If traditional photo-alignment techniques are used, then the liquid crystal panel does not require domain separators and has high aperture ratio, but the alignment material is sensitive to ultraviolet light and has limitations in controlling liquid crystal molecule alignment
Solution Approach 1:
The patent applies photo-alignment treatment to the polyimide alignment film before liquid crystal injection. This preliminary alignment of the alignment film molecules creates a controlled surface that guides liquid crystal orientation, enabling precise alignment control while reducing sensitivity to subsequent ultraviolet exposure during operation.
Solution Approach 2:
The patent uses controllable ultraviolet light sources with adjustable intensity and exposure duration to dynamically optimize the photo-alignment process. This allows precise control of the alignment degree while managing the ultraviolet sensitivity of the materials involved.
3Reliability
If VA techniques with domain separators are used, then the display panel can be manufactured, but the aperture ratio is low and the process is complicated
Solution Approach 1:
The patent removes domain separators and their associated complex manufacturing processes by using photo-alignment techniques. The alignment is achieved through controlled molecular orientation of the polyimide film via ultraviolet light, eliminating the need for physical domain separation structures and simplifying the overall manufacturing process while maintaining display performance.
4Loss of time
If Rubbing-type alignment process is used, then the process is conducted under normal temperature with short rubbing time, but the PI material is highly water-absorptive and produces residual static electricity and brush marks
Solution Approach 1:
The patent replaces mechanical rubbing with optical field-based photo-alignment. Ultraviolet light induces molecular orientation in the polyimide alignment film without mechanical contact, thereby eliminating brush marks and residual static electricity while maintaining short processing time and normal temperature conditions.
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 approach improves the contrast of the display panel by precisely controlling liquid crystal molecule alignment, avoiding the drawbacks of mechanical rubbing and enhancing productivity and uniformity.
Implementation Method 1
Non-rubbing-type process utilizes ultraviolet light to cause photopolymer monomer to react
Implementation Method 2
producing a first electrical field between the first and second electrode plates perpendicular to the array substrate
Implementation Method 3
conducting a first photo-alignment on the first alignment film using an ultra-violet light whose polarization direction is parallel to the array substrate
Data Source
AI summary
A display panel manufacturing method and a liquid crystal display device are disclosed. The method contains the following steps. Firstly, a first electrode plate, an opposing second electrode plate, and an array substrate in between are provided. Secondly, a first electrical field between the first and second electrode plates is produced, and a first photo-alignment on the first alignment film is conducted. Thirdly, a third electrode plate and an opposing color film substrate are provided. Fourthly, a second electrical field between the third electrode plate and the second transparent electrode is produced, and a second photo-alignment on the second alignment film is conducted. Finally, the array and color film substrates are joined together to form the display panel. The method is able to improve liquid crystal molecules' preset angles in the vertical direction, thereby enhancing the contrast of the display panel.