Thin Polarizing Plate Structure for Crack and Warp Prevention
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Solution Overview
Problem
Thin polarizing plates without protective films are prone to cracks, warping, and twisting due to asymmetric structures, posing challenges for applications in display devices like LCDs and OLEDs.
Innovation Solution
A polarizing plate design with a protective film and pressure-sensitive adhesive layer, where the protective film and polarizing film have controlled shrinkage forces, maintaining a total thickness of 200 µm or less, and a specific ratio of shrinkage forces to ensure structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a protective film is omitted to reduce thickness, then the polarizing plate becomes thinner, but cracks and structural defects occur due to asymmetric structure
Solution Approach 1:
The patent applies asymmetry principle by deliberately creating an asymmetric multi-layer structure with different materials (PVA film, TAC film, adhesive layers) and different thicknesses on each side of the polarizing film. This controlled asymmetry compensates for the inherent asymmetry caused by omitting the protective film, maintaining structural balance and preventing cracks while achieving reduced overall thickness.
Solution Approach 2:
The patent changes physical parameters by controlling the thickness of each layer (PVA film: 6-12 μm, TAC film: 50-100 μm, adhesive layers: 3-7 μm each) and adjusting the shrinkage forces through material selection and processing conditions. These parameter optimizations ensure the total thickness remains thin (150-200 μm) while maintaining structural integrity without protective film.
2Length of moving object
If the polarizing plate is made thinner by omitting protective film, then thickness is reduced, but warping and twisting occur
Solution Approach 1:
The patent applies counterweight principle by introducing TAC films with controlled shrinkage forces on both sides of the PVA polarizing film. These TAC films act as counterbalancing elements that offset the warping and twisting tendencies caused by the asymmetric structure and omitted protective film, maintaining flatness while achieving thin overall thickness.
Solution Approach 2:
The patent uses composite materials by combining PVA film (providing polarizing function), TAC films (providing structural support and shrinkage control), and adhesive layers (providing bonding). This composite structure achieves both thinness and shape stability through the synergistic properties of different materials with complementary functions.
3Length of moving object
If protective film is removed to achieve thinness, then thickness is reduced, but the polarizing plate induces problems when applied to display devices
Solution Approach 1:
The patent applies preliminary action by pre-controlling the shrinkage forces of the TAC films and adhesive layers during manufacturing. The shrinkage forces are adjusted in advance to match and compensate for the asymmetric structure, ensuring that when the polarizing plate is applied to display devices, it maintains structural stability and does not induce warping, twisting, or other defects.
Solution Approach 2:
The patent optimizes parameters by carefully controlling the thickness, material composition, and shrinkage force characteristics of each layer. The TAC film thickness (50-100 μm) and adhesive layer thickness (3-7 μm) are specifically tuned to provide adequate structural support while maintaining thin overall profile, preventing harmful effects on display devices.
Data Source
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AI summary
The present application relates to a polarizing plate. The present application can provide a polarizing plate which does not cause cracks or the like while having a thin thickness, does not induce warping or twisting in itself and does not induce the above problems even when applied to a display device such as an LCD or OLED.