Plastic Protective Panel Warping Control in Image Display Devices
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Solution Overview
Problem
The use of plastic protective panels in image display devices, such as liquid crystal display devices, leads to warping issues due to internal, external, and residual stresses, causing image unevenness and light leakage, which conventional methods fail to adequately address despite attempts to minimize volume shrinkage and elastic modulus of resin compositions.
Innovation Solution
The implementation of a configuration where a plastic protective panel with an outer dimension larger than the image display panel is fixed with a jig during resin curing to prevent warping, and in another configuration, the panels are sized equally to fit within a case with the resin interposed, ensuring uniform curing and minimizing warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plastic protective panel is used instead of glass, then cost is reduced and impact resistance is improved, but warping occurs due to internal, external, and residual stresses, causing image unevenness and light leakage
Solution Approach 1:
The patent modifies the resin composition parameters by incorporating specific components (polyurethane acrylate, polyisoprene-based acrylate, hydrogenated terpene resin) and controlling the curing shrinkage ratio to be 0-2%, which changes the physical and chemical properties of the cured resin to reduce warping of the plastic protective panel while maintaining cost-effectiveness and impact resistance
Solution Approach 2:
The patent uses a composite material system consisting of a multi-component resin composition that combines polyurethane acrylate, polyisoprene-based acrylate, and hydrogenated terpene resin, creating a cured resin with balanced properties that adheres to the plastic panel without causing excessive warping, thus resolving the contradiction between using plastic panels and controlling warping precision
2Reliability
If a resin composition is filled between the image display panel and protective panel and cured, then adhesion is improved and gaps are eliminated, but internal stress from curing shrinkage causes warping and image unevenness
Solution Approach 1:
The patent changes the chemical composition parameters of the resin by incorporating polyurethane acrylate and polyisoprene-based acrylate with low curing shrinkage, and controls the curing shrinkage ratio to 0-2%, which maintains strong adhesion between panels while minimizing internal stress that causes warping and image unevenness
Solution Approach 2:
The patent applies different functional properties to different components of the resin composition: polyurethane acrylate provides adhesion, polyisoprene-based acrylate reduces shrinkage stress, and hydrogenated terpene resin enhances mechanical properties, creating a locally optimized composite that achieves both strong bonding and minimal warping
3Area of stationary object
If the protective panel size is made larger than the image display panel with a shielding part, then coverage is improved, but warping tendency increases and light leakage occurs at peripheral portions
Solution Approach 1:
The patent modifies the resin composition parameters to include polyisoprene-based acrylate and control curing shrinkage to 0-2%, which reduces internal stress in the cured resin, thereby preventing warping at the peripheral portions of the enlarged protective panel while maintaining adequate coverage and eliminating light leakage
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
This approach effectively suppresses warping of the protective panel, maintains image quality, enhances outdoor visibility, and provides sufficient impact resistance, ensuring reliable image display without unevenness and light leakage.
Implementation Method 1
the resin composition is cured by UV irradiation
Data Source
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AI summary
The present invention relates to an image display device comprising an image display panel and a transparent protective panel formed from a polymethyl methacrylate which are arranged facing each other via a cured resin, wherein an outer dimension of the protective panel is substantially equal to an outer dimension of the image display panel, the outer dimension is substantially equal to an inner dimension of a case of the protective panel and the image display panel, and a substantially whole face of the protective panel is adhered to the image display panel by the cured resin.