UV-Cured Resin Layer for Display Cover Adhesion
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Solution Overview
Problem
Conventional methods for manufacturing image display devices using a light-transmitting cured resin layer between a liquid crystal display panel and a light-transmitting cover member face issues such as insufficient adhesive force, separation, and humidity ingress due to incomplete curing of the photo-curable resin composition, especially when a heat polymerization initiator is used in conjunction with a photopolymerization initiator, leading to increased capital investment and reduced preservation stability.
Innovation Solution
A method involving the application of a liquid photo-curable resin composition to a thickness greater than the light-shielding layer, pre-curing it with UV irradiation, and then stacking the image display member and light-transmitting cover member via the pre-cured resin layer, followed by complete curing with UV irradiation, effectively canceling the step between the light-shielding layer and the cover member surface without requiring a heat polymerization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a heat polymerization initiator is mixed with the photo-curable resin composition to enable heat-curing, then adhesive force can be improved, but capital investment increases and preservation stability deteriorates
Solution Approach 1:
The patent extracts and removes the heat polymerization initiator from the resin composition, eliminating the need for heat-curing equipment and processes. The solution relies solely on photopolymerization initiators and UV irradiation, thereby reducing capital investment while maintaining adhesive force through optimized photo-curing parameters.
Solution Approach 2:
The patent replaces the thermal curing mechanism (heat polymerization) with a photochemical curing mechanism (photopolymerization). By substituting the heat-based process with light-based photopolymerization, the invention eliminates the need for heat-curing equipment and achieves equivalent or superior adhesive force through UV irradiation.
2Manufacturing precision
If a light-shielding layer is provided on the light-transmitting cover member to enhance brightness and contrast, then image quality is improved, but curing of the resin composition becomes insufficient leading to separation and humidity ingress
Solution Approach 1:
The patent applies local quality by using a light-transmitting resin composition specifically in the region where the light-shielding layer is present. This localized approach allows the resin to receive sufficient UV irradiation through the light-transmitting properties, achieving complete curing and maintaining adhesive bond integrity while preserving the light-shielding function for image quality enhancement.
Solution Approach 2:
The patent changes the optical parameters of the resin composition by selecting materials with high light-transmitting properties in the UV range. This parameter change enables UV light to penetrate through the resin layer to the light-shielding layer region, ensuring complete photopolymerization and preventing adhesive failure despite the presence of the light-shielding layer.
3Shape
If the photo-curable resin composition is applied to a thickness greater than the light-shielding layer to cancel the step, then surface flatness is improved, but UV irradiation penetration becomes insufficient leading to incomplete curing
Solution Approach 1:
The patent changes the optical parameters by selecting resin composition materials with exceptional light-transmitting properties in the UV spectrum. This allows UV irradiation to penetrate through thicker resin layers, achieving complete photopolymerization even when the resin thickness exceeds the light-shielding layer thickness, thereby maintaining both surface flatness and curing completeness.
Solution Approach 2:
The patent employs periodic or extended UV irradiation protocols to ensure complete curing of thicker resin compositions. By controlling the duration and intensity of UV exposure, the system achieves thorough photopolymerization throughout the entire resin thickness, maintaining surface flatness while ensuring complete curing.
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 ensures sufficient photo-curing of the resin layer between the light-shielding layer and the image display member without elimination, enhancing adhesive strength and preventing air bubbles and interlayer delamination, while reducing capital investment and improving preservation stability.
Implementation Method 1
irradiating the composition with a UV ray and curing the composition to form a light-transmitting cured resin layer
Data Source
AI summary
According to a method of manufacturing an image display device of the present invention, a photo-curable resin composition in a liquid state is applied to a surface of a light-transmitting cover member including a light-shielding layer or a surface of the image display member to a thickness greater than that of the light-shielding layer. Then, in this state, the photo-curable resin composition is irradiated with a UV ray to be pre-cured, thereby forming a pre-cured resin layer. Next, the image display member and the light-transmitting cover member are stacked via the pre-cured resin layer and thereafter, the pre-cured resin layer is irradiated with a UV ray to be completely cured, thereby forming a light-transmitting cured resin layer.