Multi-functional Monomer for LCD Alignment Film Production
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Solution Overview
Problem
Current methods for producing alignment films for LCDs face issues such as reduced yield, contamination, increased production costs, and difficulty in producing large-sized films due to rubbing and inclined deposition processes, and existing photoreactive polymers have poor mobility and efficiency in aligning liquid crystals under light exposure.
Innovation Solution
A multi-functional monomer with a photoreactive group and a heat-curable functional group is used, allowing for rapid alignment under light exposure and improved physical properties through heat curing, enabling efficient production of alignment films with enhanced liquid crystal alignment and dichroic ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer resin film is used for alignment film production, then the alignment film can be formed on the substrate, but the yield is reduced and contrast deteriorates due to contamination from rubbing contact and static electricity
Solution Approach 1:
The patent replaces the mechanical rubbing process with a transcription process using a transcription body that transfers alignment patterns through heat and pressure. This eliminates contact between the alignment film and rubbing materials, thereby preventing contamination and static electricity generation while maintaining alignment functionality.
Solution Approach 2:
The patent uses a transcription body with pre-formed protrusions and recesses that copies its surface pattern onto the resin film through heat and pressure. This copying mechanism creates the necessary alignment structure without direct rubbing contact, avoiding contamination while achieving the desired alignment effect.
2Reliability
If inclined deposition of silicon dioxide is used to produce alignment film, then the alignment film can be formed, but production cost increases and it is difficult to produce large-sized films
Solution Approach 1:
The patent employs a transcription body that can be manufactured independently and then used to pattern the alignment film through heat and pressure. This approach allows for cost-effective production of large transcription bodies that can subsequently produce multiple large-sized alignment films, overcoming the limitations of inclined deposition for large-scale manufacturing.
Solution Approach 2:
The patent separates the alignment pattern creation into two independent stages: first manufacturing the transcription body with the desired pattern, then using it to transfer the pattern to the alignment film. This segmentation allows the transcription body to be produced using cost-effective methods and reused multiple times, reducing overall production costs and enabling large-scale film production.
3Reliability
If a polymer with photosensitive groups in the main chain is used, then the alignment film can be formed, but the photosensitive groups are restrained and cannot rapidly react with polarized light, reducing process efficiency
Solution Approach 1:
The patent separates the photosensitive groups from the polymer main chain, placing them only in the side chains. This segmentation allows the photosensitive groups to remain mobile and accessible to polarized light while the main chain provides structural integrity. The increased freedom of movement enables faster photoreaction and improved process efficiency.
Solution Approach 2:
The patent creates a dynamic structure where the side chains containing photosensitive groups can move freely relative to the main chain. This dynamic configuration allows the photosensitive groups to rapidly reorient and react with polarized light when exposed, significantly increasing the photoreaction speed compared to restrained main-chain photosensitive groups.
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 multi-functional monomer reduces production time and costs while improving the alignment regulating force of liquid crystals, increasing the dichroic ratio and thermal stability of the alignment film.
Implementation Method 1
a photoreactive group and, more particularly, to a multi-functional monomer having a photoreactive group and a heat-curable functional group
Implementation Method 2
a multi-functional monomer having a photoreactive group and a heat-curable functional group
Data Source
AI summary
Disclosed is a multi-functional monomer including a heat-curable functional group as well as a typical photoreactive group. In the multi-functional monomer, the photoreactive group is not chained to a main chain of a polymer. Thus, since it is possible to perform desirable alignment treatment even though polarized UV is radiated for a short time, the production time and the production cost are reduced and alignment regulating force of liquid crystals is increased, thereby increasing a dichroic ratio.