Optical Adhesive Bonding Composition for Image Display Devices
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Solution Overview
Problem
Adhesive bonding compositions for optical use face challenges in preventing overflow phenomena and achieving excellent bonding strength and step absorbency, particularly in image display devices, where air layers between display and protective parts degrade visibility and are difficult to apply uniformly, leading to raw material loss and productivity issues.
Innovation Solution
A methacrylate-based and acrylate-based monomer composition with a weight ratio ranging from 1:1 to 1:10, applied in a multistage curing process, primarily and secondarily photo-cured to form a bonding agent between the image display part and protective part, reducing cure shrinkage and preventing overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If adhesive film or adhesive sheet is used to fill the air layer, then visibility is improved, but it is difficult to apply to various structures and remove bubbles during adhesion
Solution Approach 1:
The patent changes the physical state of the adhesive from solid (film/sheet) to liquid, allowing it to flow and adapt to various structures. The liquid adhesive can be applied by coating methods and easily removes bubbles during adhesion, while maintaining optical transparency to improve visibility.
Solution Approach 2:
The patent uses liquid adhesive that can flow like a fluid to fill the air layer between display and protective parts. This liquid state allows the adhesive to automatically level and remove bubbles through flow, solving the application difficulty while maintaining optical properties.
2Strength
If adhesive composition is applied to bond image display part and protective part, then bonding strength is achieved, but overflow phenomenon occurs during adhesion
Solution Approach 1:
The patent applies a release agent to the protective part before applying the adhesive composition. This preliminary action prevents the adhesive from adhering to the protective part surface, thereby preventing overflow phenomenon during the adhesion process while maintaining bonding strength.
Solution Approach 2:
The release agent acts as an intermediary between the adhesive composition and the protective part. It temporarily prevents adhesion during application, allowing controlled placement without overflow, and can be removed later to enable proper bonding.
3Device complexity
If single-stage curing is used for adhesive bonding composition, then process simplicity is maintained, but curing shrinkage is large causing warpage and overflow
Solution Approach 1:
The patent divides the single-stage curing process into multiple stages: a first curing stage with controlled shrinkage, and a second curing stage to complete the bonding. This segmentation allows the adhesive to set initially without excessive shrinkage, preventing warpage and overflow, while achieving full bonding strength in the second stage.
Solution Approach 2:
The patent uses periodic curing action with two distinct stages. The first stage provides controlled, gradual curing to minimize shrinkage effects, and the second stage completes the curing process. This periodic approach prevents warpage and overflow while maintaining process manageability.
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 multistage curing method effectively prevents overflow, reduces raw material loss, and enhances bonding strength and durability, maintaining excellent visibility and surface appearance by adjusting curing rates and minimizing warpage and plasticizer migration.
Implementation Method 1
primarily photo-curing the adhesive bonding composition, and subsequently, a bonding agent may be formed by adhering the protective part onto a top of the adhesive agent, and then secondarily photo-curing the adhesive agent
Data Source
AI summary
Provided are an adhesive bonding composition for optical use and a multistage curing method thereof, the composition including a methacrylate-based monomer and an acrylate-based monomer, in which a weight ratio of the methacrylate-based monomer to the acrylate-based monomer ranges from about 1:1 to about 1:10.