Gradient Elastic Modulus Pressure-Sensitive Adhesive for Polarizing Plate
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Solution Overview
Problem
Conventional polarizing plates for LCD devices face challenges due to the moisture vulnerability and optical property degradation of hydrophilic resin polarizers, especially under humid conditions, which complicates achieving desired performance without protective films.
Innovation Solution
A pressure-sensitive adhesive with a gradient elastic modulus along its thickness direction is used, formed into a film with varying peel strengths on its surfaces, incorporating an interpenetrating polymer network and specific polymer structures to enhance durability and prevent light leakage, allowing for a thinner, lighter polarizing plate without protective films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protective films are attached to both surfaces of the polarizer, then durability and water resistance are improved, but device complexity and thickness increase
Solution Approach 1:
The patent removes one of the two protective films from the conventional dual-film structure, extracting the unnecessary layer while maintaining adequate protection through the gradient elastic modulus design of the pressure-sensitive adhesive
Solution Approach 2:
The pressure-sensitive adhesive is designed with non-uniform elastic modulus distribution, having higher elastic modulus at the interface with the polarizer and lower elastic modulus at the outer surface, creating local quality variations that provide both strong adhesion and flexibility without requiring protective films
2Reliability
If protective films are attached to both surfaces of the polarizer, then water resistance is improved, but thickness and weight increase
Solution Approach 1:
The patent eliminates one protective film from the conventional structure, reducing the overall weight of the polarizing plate while maintaining water resistance through the gradient elastic modulus pressure-sensitive adhesive
Solution Approach 2:
The pressure-sensitive adhesive uses gradient elastic modulus parameters to provide protective functions equivalent to protective films but with reduced thickness and weight, achieving water resistance through material property variation rather than additional layers
3Ease of manufacture
If conventional pressure-sensitive adhesive is used, then ease of manufacture is maintained, but light leakage prevention and durability under humid conditions deteriorate
Solution Approach 1:
The pressure-sensitive adhesive is designed with spatially varying elastic modulus, having higher stiffness at the polarizer interface for strong bonding and lower stiffness at the outer surface to prevent light leakage, achieving both durability and optical performance through local property differentiation
Solution Approach 2:
The pressure-sensitive adhesive uses a composite formulation combining acrylic polymer with specific ratios of alkyl acrylate and hydroxyl-containing monomer, creating a material with gradient elastic modulus that provides both manufacturing ease and superior light leakage prevention
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 effectively prevents light leakage and ensures excellent durability of the polarizing plate, maintaining suitable adhesive strength and optical properties even under humid conditions, enabling a thinner and lighter polarizing plate for LCD devices.
Implementation Method 1
a liquid crystal display (LCD) device is applied in various fields because it has low power consumption and can be formed in a thin plane... polarizing plates attached to both surfaces of the liquid crystal panel, by means of a pressure-sensitive adhesive
Data Source
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AI summary
Provided are a pressure-sensitive adhesive, a polarizing plate, and a liquid crystal display device. The pressure-sensitive adhesive may be used to provide a polarizing plate which has a tensile modulus that varies in a thickness direction, and for example, which has a smaller thickness and a lighter weight, and also satisfies all of the physical properties required for the polarizing plate such as durability, water resistance, workability and light leakage preventability, and a liquid crystal display device including the same.