UV-Cured Resin Layer Adhesion in Image Displays
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Solution Overview
Problem
Existing methods for manufacturing image display devices using photocurable resin compositions face challenges such as insufficient adhesive strength and adhesion retainability, particularly when a thermal polymerization process is not used, leading to issues like peeling and air bubbles between the light-transmitting cover member and the image display member.
Innovation Solution
A photocurable resin composition comprising an acrylate-based oligomer, acrylic-based monomer, plasticizer, and photopolymerization initiator, with specific mass ratios and components, is used to form a light-transmitting cured resin layer, allowing for complete photo-curing without thermal polymerization, enhancing adhesion and shape retainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thermal polymerization process is added to cure the resin composition between the light-shielding layer and image display member, then adhesive strength is improved, but capital investment burden increases and storage stability decreases
Solution Approach 1:
The invention extracts the thermal polymerization step from the curing process, using only photopolymerization initiated by ultraviolet light. This eliminates the need for thermal processing equipment and reduces process complexity while maintaining adequate adhesive strength through optimized photocurable resin formulation and UV irradiation parameters.
Solution Approach 2:
The invention changes the curing mechanism from thermal to photopolymerization by adjusting the resin composition to include photopolymerization initiators and selecting appropriate UV irradiation parameters (intensity, duration, wavelength). This parameter change eliminates thermal processing equipment requirements while achieving sufficient adhesion.
2Strength
If the light-transmitting cover member is coated with resin composition before stacking, then adhesion is improved, but the resin is excluded from the gap between the light-shielding layer and cover member, causing steps and air bubbles
Solution Approach 1:
The invention applies a preliminary thin layer of photocurable resin to the light-transmitting cover member surface before stacking with the image display member. This preliminary coating ensures adequate resin presence in the bonding gap while maintaining surface flatness, as the thin layer can be uniformly distributed without creating excessive steps or air bubbles.
Solution Approach 2:
The invention applies resin locally to specific areas of the light-transmitting cover member where bonding is required, rather than uniformly coating the entire surface. This localized application ensures resin presence in the bonding gap while minimizing surface irregularities and air bubble formation.
3Ease of manufacture
If the resin composition is cured by UV irradiation only, then process simplicity is improved, but adhesive strength between the light-shielding layer and image display member is insufficient
Solution Approach 1:
The invention uses a composite photocurable resin composition containing multiple components including photopolymerization initiators, oligomers, and monomers in specific ratios. This composite formulation enables adequate adhesive strength to be achieved through photopolymerization alone, eliminating the need for thermal processing while maintaining bonding performance.
Solution Approach 2:
The invention optimizes photopolymerization parameters including UV irradiation intensity, duration, and wavelength, along with resin composition parameters such as initiator concentration and monomer/oligomer ratios. These parameter optimizations enable sufficient adhesive strength to be achieved through photopolymerization alone, simplifying the manufacturing process.
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 composition ensures improved adhesion and shape retainability of the cured resin layer, preventing peeling and air bubbles, and maintaining adhesion even after thermal stress, thus enhancing the manufacturing process for image display devices.
Implementation Method 1
curing the composition by irradiation with ultraviolet rays to form a light-transmitting cured resin layer
Data Source
AI summary
A UV-photocured resin layer (and an image display device including the UV-photocured resin layer), the UV-photocured resin layer including the following cured components: an acrylate-based oligomer component selected from the group consisting of a polyisoprene-based (meth)acrylate oligomer, a polybutadiene-based (meth)acrylate oligomer, and a polyurethane-based (meth)acrylate oligomer; an acrylic-based monomer component; a plasticizer component; and a photoradical polymerization initiator component.