Optical Laminate Elasticity Control for Moist-Heat Durability
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Solution Overview
Problem
Optical laminates used in image display devices experience durability issues under high-temperature and high-humidity environments, leading to surface reflection unevenness due to deformation of the resin layer.
Innovation Solution
The optical laminate is configured with a specific relationship between the storage elastic modulus of the pressure sensitive adhesive layer and the storage elastic modulus and moist heat strain of the resin layer, satisfying Expressions (1-1) and (1-2), which prevents deformation and wrinkles in the resin layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photo-alignment layer or resin layer is used in the optical laminate, then the alignment and optical properties are improved, but the durability against high-temperature and high-humidity environments deteriorates due to deformation and surface reflection unevenness
Solution Approach 1:
The patent applies parameter changes by establishing specific quantitative relationships between the storage elastic modulus of the pressure sensitive adhesive layer (Ep) and the storage elastic modulus (Ea) and moist heat strain (Sa) of the resin layer. By controlling these mechanical parameters to satisfy specific expressions, the patent prevents deformation of the resin layer under high-temperature and high-humidity conditions, thereby maintaining surface reflection uniformity while ensuring durability.
2Reliability
If the storage elastic modulus of the pressure sensitive adhesive layer is increased to prevent deformation, then the durability is improved, but the flexibility and ease of bonding deteriorate
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the storage elastic modulus Ep of the pressure sensitive adhesive layer within a specific range defined by mathematical expressions involving the resin layer's properties (Ea and Sa). This parameter optimization ensures that the adhesive layer has sufficient stiffness to prevent resin layer deformation under thermal stress while maintaining adequate flexibility for practical bonding operations.
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 laminate achieves enhanced durability and resistance to high-temperature and high-humidity conditions, maintaining consistent surface reflection without unevenness.
Implementation Method 1
a storage elastic modulus Ep of the pressure sensitive adhesive layer 1 and a storage elastic modulus Ea and a moist heat strain Sa of the resin layer satisfy a predetermined relationship
Implementation Method 2
the light absorption anisotropic layer contains a dichroic substance
Data Source
AI summary
Provided is an optical laminate with excellent durability and an image display device formed of the optical laminate. The optical laminate includes a pressure sensitive adhesive layer 1, a specific laminate including a resin layer and a light absorption anisotropic layer which are adjacent to each other, and a pressure sensitive adhesive layer 2 in order, in which the light absorption anisotropic layer contains a dichroic substance, the pressure sensitive adhesive layer 1 is adjacent to the resin layer of the specific laminate, and a storage elastic modulus Ep of the pressure sensitive adhesive layer 1 and a storage elastic modulus Ea and a moist heat strain δa of the resin layer satisfy Expression (1-1) ¼ (3×Ep/Ea)2/3>δa.