Optical Film Alignment Composition Suppressing Bright Point Defects
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Solution Overview
Problem
Optical films with optically anisotropic layers often suffer from bright point defects due to scraps generated during the rubbing treatment of alignment films, which affect display performance and application diversity.
Innovation Solution
An optical film comprising an alignment film and an optically anisotropic layer, where the alignment film is formed using a composition with an additive having an alkyl group of 5 to 29 carbon atoms and a polymer with no alkyl group, improving alignment properties and reducing bright point defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubbing treatment is applied to the alignment film to impart alignment restricting force, then the alignment properties of liquid crystal compound are improved, but bright point defects occur due to scraps generated during rubbing
Solution Approach 1:
The invention extracts and removes the harmful rubbing treatment process from the manufacturing flow. By replacing the rubbing treatment with a non-rubbing alignment method using the specific polymer composition, the source of bright point defects (scraps generated during rubbing) is completely eliminated while still achieving the necessary alignment restricting force for liquid crystal orientation.
Solution Approach 2:
The invention substitutes the mechanical rubbing treatment with a chemical/physical alignment mechanism. Instead of using mechanical friction and contact to impart alignment restricting force, the patent employs a specially formulated polymer composition that provides alignment through its molecular structure and interaction with liquid crystal compounds, thereby eliminating mechanical scraps and bright point defects.
2Ease of manufacture
If conventional alignment film composition is used, then the manufacturing process is simple, but bright point defects occur and alignment properties need improvement
Solution Approach 1:
The invention changes the chemical composition parameters of the alignment film by specifying a polymer with particular properties: no alkyl groups with 5 to 29 carbon atoms, and containing at least one of specific functional groups. This parameter change in the polymer composition enables the film to provide adequate alignment restricting force without requiring rubbing treatment, thus preventing bright point defects while maintaining manufacturing simplicity.
Solution Approach 2:
The invention uses a composite polymer composition comprising multiple components with specific characteristics. The polymer blend is designed to combine the benefits of different materials: providing both the necessary alignment properties and defect suppression, while maintaining ease of manufacture through a single coating process that forms the alignment film with the required functional properties.
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 solution enhances the alignment properties of liquid crystal compounds in optically anisotropic layers while suppressing bright point defects, leading to improved display performance and broader application possibilities.
Implementation Method 1
the alignment film is a film formed of a composition for forming an alignment film, containing an additive having an alkyl group having 5 to 29 carbon atoms and a polymer having no alkyl group having 5 to 29 carbon atoms
Data Source
AI summary
An optical film having good alignment properties of a liquid crystal compound in an optically anisotropic layer while suppressing an occurrence of bright point defects, an optically anisotropic layer, a composition for forming an alignment film, a method for producing an optical film, a polarizing plate, and an image display device. The optical film includes an alignment film and an optically anisotropic layer, in which the optically anisotropic layer is a layer formed of a composition for forming an optically anisotropic layer, containing a polymerizable liquid crystal compound, and the alignment film is a film formed of a composition for forming an alignment film, containing an additive having an alkyl group having 5 to 29 carbon atoms and a polymer having no alkyl group having 5 to 29 carbon atoms.