Front-Plate-Integrated Polarizing Plates for LCD Warping Control
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Solution Overview
Problem
Conventional liquid crystal display panels experience warping issues in high temperature environments due to the shrinkage of polarizing plates, particularly when the front plate is integrated with a pressure sensitive adhesive or ultraviolet curing resin for improved visibility, leading to accommodation problems in final products.
Innovation Solution
A set of polarizing plates comprising a front-plate-integrated polarizing plate with a Young's modulus of 2 GPa or greater, and a back-side polarizing plate, where the distance from the liquid crystal cell to the polarizer of the front-plate-integrated polarizing plate is greater than that of the back-side polarizing plate, ensuring a relationship of d1 > d2, with d1 up to 100 μm and d2 5 μm or more, to minimize warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the front plate is integrated with the liquid crystal display panel using pressure sensitive adhesive or ultraviolet curing resin, then visibility is enhanced by eliminating reflection and scattering at interfaces, but warping occurs in high temperature environments
Solution Approach 1:
The patent applies parameter changes by specifying a minimum thickness of 2 μm for the polarizing film on the front plate and a minimum Young's modulus of 2 GPa for the front plate material. These parameter thresholds ensure the front plate has sufficient rigidity to resist thermal warping while maintaining optical transparency for enhanced visibility.
Solution Approach 2:
The patent employs composite materials by combining the front plate (with Young's modulus ≥2 GPa) and polarizing film (thickness ≥2 μm) as an integrated structure. This composite construction provides both the optical clarity needed for visibility enhancement and the mechanical strength required to suppress warping in high temperature environments.
2Weight of stationary object
If the thickness of the liquid crystal cell and front plate is reduced, then weight and thickness of the display panel are reduced, but warping increases in high temperature environments
Solution Approach 1:
The patent uses parameter changes by establishing minimum thresholds: polarizing film thickness of at least 2 μm and front plate Young's modulus of at least 2 GPa. These parameters ensure that even when overall dimensions are reduced for lighter and thinner devices, the critical structural components maintain sufficient rigidity to prevent thermal warping.
Solution Approach 2:
The patent applies local quality by concentrating mechanical strength requirements specifically on the front plate and polarizing film interface region. By ensuring the front plate has high Young's modulus (≥2 GPa) and the polarizing film has adequate thickness (≥2 μm), the patent locally reinforces the structure where thermal stress is most problematic, while allowing other parts of the device to remain thin and light.
3Shape
If the polarizing film thickness is reduced to suppress warping, then warping is reduced, but the liquid crystal display panel with integrated front plate may still warp due to thermal shrinkage
Solution Approach 1:
The patent employs composite materials by creating an integrated front-plate-polarizing plate structure where the front plate (Young's modulus ≥2 GPa) and polarizing film (thickness ≥2 μm) work together. This composite structure provides both warping suppression and thermal stability, as the rigid front plate compensates for thermal shrinkage of the polarizing film while maintaining optical performance.
Solution Approach 2:
The patent applies parameter changes by setting minimum thresholds that balance warping suppression and thermal stability: polarizing film thickness of at least 2 μm prevents excessive shrinkage, while front plate Young's modulus of at least 2 GPa provides sufficient rigidity to maintain dimensional stability under thermal stress.
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 suppresses warping of the liquid crystal display panel to an absolute value of 0.5 mm or less when heated at 85° C. for 240 hours, allowing the panel to be accommodated in a casing, thereby resolving the thermal expansion issues.
Implementation Method 1
stuck via an ultraviolet curing type resin or a pressure sensitive adhesive
Data Source
AI summary
Provided are a set of polarizing plates comprising a front-plate-integrated polarizing plate to be disposed at a viewing side of a liquid crystal cell and a back-side polarizing plate to be disposed at a back side of the cell, and a front-plate-integrated liquid crystal display panel including the set of polarizing plates. The front-plate-integrated polarizing plate including a front-side polarizing plate and a front plate disposed at a viewing side of the front-side polarizing plate, being stuck via an ultraviolet curing type resin or a pressure sensitive adhesive, and having a Young's modulus of at least 2 GPa. A distance d1 to the liquid crystal cell from the surface of a polarizer of the front-side polarizing plate is larger than a distance d2 to the liquid crystal cell from the surface of a polarizer of the back-side polarizing plate.