Optical Laminate Durability via Adhesive Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices with cycloolefin-based polymer retardation layers face durability issues when used in harsh environments such as outdoor signage or industrial applications due to the impact of organic low-molecular-weight components in pressure sensitive adhesive layers.
Innovation Solution
Incorporating an interlayer between the retardation layer and the pressure sensitive adhesive layer, or reducing the content of organic low-molecular-weight components in the adhesive, while ensuring specific optical and mechanical properties are maintained, such as in-plane and thickness direction retardation values, and using a polymer film with a thickness of 0.1 to 50 μm to enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an organic low-molecular-weight component is contained in the pressure sensitive adhesive layer to ensure adhesion, then the adhesive performance is improved, but the durability in harsh environments deteriorates
Solution Approach 1:
The patent extracts and removes the harmful organic low-molecular-weight component (with molecular weight of 32 to 200) from the pressure sensitive adhesive layer while maintaining necessary adhesive functionality through alternative means, thereby eliminating the cause of durability degradation in harsh environments
Solution Approach 2:
The patent changes the chemical composition parameters of the pressure sensitive adhesive layer by controlling the content of organic low-molecular-weight components to be 2.6% by mass or less, and by ensuring that after durability testing at 115°C for 100 hours, the content remains at 50% or less of the initial value, thus improving durability while maintaining adhesion
2Reliability
If the content of organic low-molecular-weight component is reduced to improve durability, then the durability is improved, but the adhesive strength may deteriorate
Solution Approach 1:
The patent optimizes the parameter of organic low-molecular-weight component content in the pressure sensitive adhesive layer, setting it at 2.6% by mass or less, which balances durability improvement with maintenance of sufficient adhesive strength through controlled composition
3Reliability
If an interlayer is added between the retardation layer and pressure sensitive adhesive layer to improve durability, then the durability is improved, but the device complexity increases
Solution Approach 1:
The patent segments the optical laminate structure by adding an interlayer between the retardation layer and pressure sensitive adhesive layer, which physically separates and protects the retardation layer from harmful components while maintaining the functional integrity of each layer
Solution Approach 2:
The interlayer acts as an intermediary protective barrier between the retardation layer and the pressure sensitive adhesive layer, preventing direct contact and interaction that would cause degradation, thus improving durability without requiring fundamental design changes
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 significantly improves the durability of the optical laminate and image display devices by reducing the content of organic low-molecular-weight components and maintaining optimal optical characteristics, thereby enhancing their performance in demanding environments.
Implementation Method 1
optical compensation particularly for a decrease in contrast and color shift due to light leakage in visual recognition in an oblique direction is known to be required
Implementation Method 2
a pressure sensitive adhesive layer
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 polarizer, a retardation layer including a cycloolefin-based polymer film, and a pressure sensitive adhesive layer in this order, in which the polarizer includes a protective layer on at least one side, and specific conditions are satisfied.