Polymer Compound for Phase Difference Layer Alignment
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Solution Overview
Problem
Existing phase difference films used in liquid crystal display devices suffer from insufficient alignment and surface unevenness, particularly when used without an alignment film.
Innovation Solution
A polymer compound with specific repeating units and acid and hydroxyl values is blended into a liquid crystal composition before alignment, forming a phase difference layer with high alignment and suppressed surface unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a homeotropic alignment liquid crystal film is produced by directly coating a plastic substrate with a polymerizable and reactive liquid crystal mixture solution including a surfactant, then the alignment film is formed without requiring an alignment film, but the alignment is insufficient and surface unevenness may occur
Solution Approach 1:
The invention changes the chemical parameters of the liquid crystal composition by incorporating a polymerizable monomer and specific additives, transforming the coating solution into a composition that can achieve proper alignment and surface uniformity when polymerized, thereby resolving the contradiction between eliminating the alignment film and maintaining alignment quality
Solution Approach 2:
The invention uses a composite liquid crystal composition containing multiple components including polymerizable monomers, surfactants, and specific additives that work together to achieve both the elimination of the alignment film and the maintenance of high alignment quality and surface uniformity
2Length of stationary object
If the phase difference layer is formed without an alignment film to reduce device thickness, then the device structure is simplified, but alignment insufficiency and surface unevenness occur
Solution Approach 1:
The invention modifies the chemical composition parameters of the liquid crystal mixture to include polymerizable components that, upon polymerization, provide the necessary alignment control and surface uniformity, enabling the elimination of the alignment film while maintaining optical quality
Solution Approach 2:
The invention replaces the mechanical alignment function previously provided by a separate alignment film with a chemical alignment mechanism embedded in the polymerizable liquid crystal composition, allowing the alignment function to be integrated into the phase difference layer itself
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 polymer compound enhances the alignment of the phase difference layer and reduces surface unevenness, improving the performance of liquid crystal display devices by ensuring uniformity and optical quality.
Implementation Method 1
by blending a polymer compound which has a specific repeating unit and satisfies a predetermined acid value and hydroxyl value into a liquid crystal composition before alignment state of a liquid crystalline compound is fixed
Implementation Method 2
a liquid crystal composition comprising: the polymer compound according to any one of [1] to 11; and a liquid crystalline compound having a polymerizable group
Data Source
AI summary
An object of the present invention is to provide a polymer compound which can form a phase difference layer having high alignment and suppressed surface unevenness by being blended into a liquid crystal composition, and a liquid crystal composition, a phase difference layer, an optical film, a polarizing plate, and an image display device using the same. The polymer compound of the present invention includes a repeating unit represented by Formula (I), a repeating unit represented by Formula (II), and a repeating unit represented by Formula (III), in which an acid value is 115 mgKOH/g or more, and a hydroxyl value is 70 mgKOH/g or more.