Polarizing Plate Adhesive Layer Design for LCD Durability
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Solution Overview
Problem
Conventional polarizing plates for liquid crystal display devices face challenges in maintaining desired performance without protective films, leading to issues with durability, optical properties, and water resistance due to the low dimensional stability of polyvinyl alcohol-based polarizers.
Innovation Solution
A polarizing plate structure is developed with an adhesive layer directly attached to the polarizer and a pressure-sensitive adhesive layer directly attached to the adhesive layer, eliminating the need for protective films, while ensuring physical properties and water resistance through controlled thicknesses and tensile moduli of the adhesive and pressure-sensitive adhesive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If protective films are omitted from the polarizer to reduce thickness and weight, then the polarizing plate becomes thinner and lighter, but the dimensional stability, durability, and water resistance deteriorate
Solution Approach 1:
The protective function is segmented into two distinct layers: an adhesive layer (10-600 nm thick) directly bonded to the polarizer for dimensional stability, and a pressure-sensitive adhesive layer (10-80 μm thick) for protection and mounting. This segmentation allows each layer to specialize in specific functions, enabling thinness while maintaining stability.
Solution Approach 2:
The invention uses a composite structure combining the polarizer with two adhesive layers having different material properties and thicknesses. The adhesive layer provides strong bonding and dimensional stability, while the pressure-sensitive adhesive layer provides protection and ease of mounting, achieving both thinness and functional performance.
2Weight of stationary object
If protective films are omitted to reduce weight, then the polarizing plate becomes lighter, but the durability and adhesion performance worsen
Solution Approach 1:
The protective and adhesive functions are segmented into two layers: the adhesive layer ensures strong bonding and durability through direct attachment to the polarizer, while the pressure-sensitive adhesive layer provides additional protection and ease of handling, achieving both lightness and reliability.
Solution Approach 2:
The invention optimizes the thickness parameters of the adhesive layers (adhesive layer: 10-600 nm, pressure-sensitive adhesive layer: 10-80 μm) to achieve the right balance between weight reduction and durability maintenance, using controlled thickness to optimize performance.
3Device complexity
If a single adhesive layer is used to simplify the structure, then the device complexity is reduced, but the water resistance and adhesion performance are insufficient
Solution Approach 1:
The adhesive system is segmented into two layers with distinct functions: the adhesive layer provides strong bonding and water resistance through direct contact with the polarizer, while the pressure-sensitive adhesive layer provides additional protection and mounting functionality, together achieving superior water resistance without excessive complexity.
Solution Approach 2:
The invention employs a composite adhesive structure where two different adhesive materials work synergistically, with the adhesive layer providing baseline protection and the pressure-sensitive adhesive layer enhancing water resistance and ease of application, achieving high performance with manageable complexity.
Data Source
AI summary
Provided are a polarizing plate and a liquid crystal display device. The polarizing plate, which is lightweight and has a thin thickness and excellent physical properties including durability, water resistance, workability, pressure-sensitive adhesion and a light leakage prevention effect; and the liquid crystal display device including the same are provided.