Optical Laminate Surface Tension Control for Defect-Free Film Formation
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Solution Overview
Problem
Conventional optical laminates used in organic EL display devices often suffer from film thickness unevenness and point defects due to direct contact between optically anisotropic layers, leading to reduced contrast and glare issues.
Innovation Solution
The method involves forming optically anisotropic layers A and B with specific surface tensions, using a fluorine compound in both layers, and ensuring that the surface tension difference between them satisfies certain conditions, thereby preventing aggregate floating and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If optically anisotropic layers are in direct contact with each other, then the device complexity is reduced, but film thickness unevenness and point defects occur
Solution Approach 1:
The invention changes the surface tension parameter of the optically anisotropic layers by incorporating fluorine compounds. Specifically, it controls the surface tension of the first optically anisotropic layer to be 20.0 mN/m or less and the second layer to be 22.0 mN/m or less, with a difference of 0.5 mN/m or more between them. This parameter control prevents aggregate floating and eliminates point defects while maintaining direct contact between layers.
Solution Approach 2:
The invention applies different surface tension characteristics to different layers. The first optically anisotropic layer has a surface tension of 20.0 mN/m or less, while the second layer has a surface tension of 22.0 mN/m or less. This local differentiation in surface tension properties prevents defects at the interface while maintaining overall structural simplicity.
2Device complexity
If optically anisotropic layers are in direct contact with each other, then the device complexity is reduced, but point defects are generated
Solution Approach 1:
The invention changes the surface tension parameter of the optically anisotropic layers by incorporating fluorine compounds. Specifically, it controls the surface tension of the first optically anisotropic layer to be 20.0 mN/m or less and the second optically anisotropic layer to be 22.0 mN/m or less, with a difference of 0.5 mN/m or more between them. This parameter control prevents aggregate floating and eliminates point defects while maintaining direct contact between layers.
Solution Approach 2:
The invention uses fluorine compounds as additives in the coating solutions to modify surface tension. These are simple chemical additives that provide the necessary surface tension control without requiring complex structural modifications, achieving reliable defect-free performance through straightforward material selection.
3Manufacturing precision
If fluorine compound is added to control surface tension, then film thickness unevenness is suppressed, but the composition complexity increases
Solution Approach 1:
The invention changes the surface tension parameter of the optically anisotropic layers by incorporating fluorine compounds. Specifically, it controls the surface tension of the first optically anisotropic layer to be 20.0 mN/m or less and the second optically anisotropic layer to be 22.0 mN/m or less, with a difference of 0.5 mN/m or more between them. This parameter control prevents aggregate floating and eliminates point defects while maintaining direct contact between layers.
Solution Approach 2:
The invention creates composite coating solutions by combining fluorine compounds with liquid crystal compounds. The fluorine compound serves as a surface tension modifier added to the liquid crystal composition, creating a composite material that achieves both the desired optical properties and controlled surface tension for defect-free film formation.
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 results in an optical laminate with suppressed film thickness unevenness and absence of point defects, enhancing the optical performance and reliability of the organic EL display devices.
Implementation Method 1
the surface tension of a predetermined solution containing this fluorine compound satisfies a specific relationship between optically anisotropic layers that are in direct contact with each other
Data Source
AI summary
The present invention provides an optical laminate which is suppressed in film thickness unevenness of an optically anisotropic layer and is free from point defects, a method of producing the same, and a polarizing plate and an organic EL display device using the optical laminate. The method of producing an optical laminate having an optically anisotropic layer A and an optically anisotropic layer B, includes where the layer A and the layer B are provided in direct contact with each other. The method further includes where both a composition a for forming the layer A and a composition b for forming the layer B contain a fluorine compound, and when the layer A is formed using composition a and layer B is formed using composition b, layer A and layer B are formed in this order under the condition that composition a and composition b satisfy predetermined surface tension relationships.