Adhesive Composition for Display Edge Bubble Prevention
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Solution Overview
Problem
Existing adhesive compositions for display apparatuses face challenges in maintaining reliability, particularly at edge portions, due to the formation of penetrating bubbles after pressure removal from the adhesive layer, especially in bending areas.
Innovation Solution
An adhesive composition comprising (meth)acrylate with an alicyclic group, a low-temperature glass transition (meth)acrylic monomer, (meth)acrylate with a hydroxyl group, a high-temperature glass transition (meth)acrylic monomer, and a reactive diluent monomer, which minimizes the occurrence of penetrating bubbles by enhancing the tensile strength and creep resistance of the adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesive compositions are used to bond the cover window to the display panel, then the adhesive layer provides basic bonding function, but penetrating bubbles form at edge portions especially in bending areas after pressure removal, reducing reliability
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive by incorporating specific monomers (alicyclic group-containing, hydroxyl group-containing, and high glass transition temperature components) in controlled ratios. This changes the physical and chemical properties of the adhesive layer, enhancing its tensile strength and creep resistance to prevent bubble formation and penetration at edge portions during bending operations.
Solution Approach 2:
The patent creates a composite adhesive system by combining multiple types of monomers with different functional properties: alicyclic group-containing monomers for structural integrity, hydroxyl group-containing monomers for adhesion enhancement, and high glass transition temperature monomers for thermal stability. This composite approach synergistically improves the adhesive layer's resistance to bubble formation and penetration.
2Volume of moving object
If the adhesive layer is made thinner to support thinner display apparatus designs, then the display apparatus becomes more compact, but the adhesive layer's ability to prevent bubble penetration and maintain reliability at edges deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive to achieve superior mechanical properties (tensile strength and creep resistance) that compensate for reduced thickness. By optimizing the ratio of alicyclic group-containing monomers (5-15 wt%), hydroxyl group-containing monomers (5-20 wt%), and high glass transition temperature monomers (60-85 wt%), the adhesive layer maintains high reliability even at reduced thicknesses suitable for compact display designs.
3Reliability
If the adhesive composition is optimized for high tensile strength to prevent bubble formation, then reliability improves, but the complexity of the composition increases with multiple monomer types and ratios
Solution Approach 1:
The patent defines specific parameter ranges for each monomer component to achieve the desired tensile strength and creep resistance. By specifying that alicyclic group-containing monomers comprise 5-15 wt%, hydroxyl group-containing monomers comprise 5-20 wt%, and high glass transition temperature monomers comprise 60-85 wt%, the composition achieves high reliability while maintaining manageable complexity through clearly defined formulation parameters.
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 proposed adhesive composition effectively reduces the formation of penetrating bubbles at edge portions of display apparatuses, thereby enhancing the reliability and reducing the defect rate in bending areas.
Implementation Method 1
an adhesive composition comprising (meth)acrylate having an alicyclic group, a low-temperature glass transition (meth)acrylic monomer, (meth)acrylate having a hydroxyl group, a high-temperature glass transition (meth)acrylic monomer, and a reactive diluent monomer
Data Source
AI summary
Provided are an adhesive composition having enhanced reliability at edge portions of a display apparatus and the display apparatus, the display apparatus including a display panel displaying an image to the outside, a cover window arranged on the display panel, and an adhesive layer interposed between the display panel and the cover window, the adhesive layer including an adhesive composition including (meth)acrylate having an alicyclic group, a low-temperature glass transition (meth)acrylic monomer, (meth)acrylate having a hydroxyl group, a high-temperature glass transition (meth)acrylic monomer, and a reactive diluent monomer, in which a maximum value of stress of the adhesive composition, with the stress changing over time when a strain of 25% is applied at 60° C. to the adhesive layer, is from about 30000 Pa to about 40000 Pa.