Liquid Crystal Composition for Optically Anisotropic Layer Light Resistance
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Solution Overview
Problem
Existing optically anisotropic layers used in image display devices face challenges with light resistance and contrast, particularly in the compositions described in JP2016-081035A and JP2019-105851A, indicating a need for improved formulations to enhance these properties.
Innovation Solution
A liquid crystal composition is developed containing a liquid crystal compound and a non-liquid crystal compound with specific aromatic rings, where the molecular weight ratio of the non-liquid crystal compound to the liquid crystal compound is 1 or less, and both compounds exhibit reverse wavelength dispersibility, improving light resistance and contrast in the optically anisotropic layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optically anisotropic layer is formed using a liquid crystal compound as described in JP2016-081035A, then the optical anisotropy is achieved, but the light resistance is insufficient
Solution Approach 1:
The patent uses a composite liquid crystal composition containing multiple liquid crystal compounds with different molecular weights and aromatic ring structures. This composite approach improves light resistance by combining the advantages of different compounds while maintaining the necessary optical anisotropy properties.
Solution Approach 2:
The patent systematically varies parameters including molecular weight ratios (maintaining Mw(MLC-1)/Mw(MLC-2) between 0.5-2.0), aromatic ring substitution patterns, and chemical structures of liquid crystal compounds to optimize both light resistance and optical performance. This parameter optimization resolves the contradiction by finding the optimal balance point.
2Reliability
If the molecular weight ratio of non-liquid crystal compound to liquid crystal compound is increased, then the light resistance improves, but the contrast of the image display device deteriorates
Solution Approach 1:
The patent precisely controls the molecular weight ratio parameter (Mw(MLC-1)/Mw(MLC-2) between 0.5-2.0) to achieve the optimal balance between light resistance and image contrast. This parameter optimization ensures that neither property is sacrificed for the other.
Solution Approach 2:
The patent introduces compounds with specific local aromatic ring structures (different substitution patterns and positions) to enhance light resistance in specific regions of the optical spectrum while maintaining overall contrast performance. This localized structural optimization resolves the contradiction.
3Stability of the object's composition
If a polymerizable liquid crystal compound is used to form the optically anisotropic layer, then the layer can be cured to improve stability, but the contrast and light resistance remain insufficient
Solution Approach 1:
The patent combines polymerizable liquid crystal compounds with non-polymerizable liquid crystal compounds in a composite formulation. This composite approach maintains the curing stability benefit while the non-polymerizable components contribute to improved light resistance and contrast properties that were insufficient in previous single-component systems.
Solution Approach 2:
The patent optimizes the ratio and molecular weight parameters of the composite liquid crystal compounds to achieve simultaneous improvement in light resistance, contrast, and stability. By carefully controlling these parameters, the patent resolves the contradiction between stability and optical performance.
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 proposed liquid crystal composition significantly enhances the light resistance and contrast of the optically anisotropic layer, leading to improved performance in image display devices by suppressing light absorption and increasing the number of moles with a small addition amount, thereby achieving better optical compensability.
Implementation Method 1
both of the liquid crystal compound and the non-liquid crystal compound are compounds having any of aromatic rings selected from the group consisting of groups represented by Formulae (Ar-1) to (Ar-7) and a ratio of a molecular weight of the non-liquid crystal compound to a molecular weight of the liquid crystal compound is 1 or less
Implementation Method 2
the light resistance of an optically anisotropic layer thus formed is improved, and the contrast of an image display device having the optically anisotropic layer is also good
Implementation Method 3
an optical film having an optically anisotropic layer consisting of a liquid crystal compound instead of the stretched birefringent film
Implementation Method 4
A stretched birefringent film has been used as the optical film
Data Source
AI summary
A liquid crystal composition containing a liquid crystal compound and a non-liquid crystal compound, in which both of the liquid crystal compound and the non-liquid crystal compound are compounds having any of aromatic rings selected from the group consisting of groups represented by predetermined formulae, and a ratio of a molecular weight of the non-liquid crystal compound to a molecular weight of the liquid crystal compound is 1 or less.