Adhesive Layer Hardness for Display Panel Impact Resistance
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Solution Overview
Problem
Display devices face issues with substrate detachment and crack formation due to external impacts, as existing adhesive layers lack sufficient hardness to prevent tilting and misalignment of the window and display panel substrates.
Innovation Solution
An adhesive composition with a high hardness is developed, comprising an oligomer, multiple monomers with varying glass transition temperatures, and a photopolymerization initiator, which forms an adhesive layer with a shore A hardness of more than 10, effectively bonding the display panel and window while distributing external impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional adhesive layer is used to bond the display panel and window, then the device can be assembled, but the adhesive layer lacks sufficient hardness to prevent substrate detachment and crack formation under external impacts
Solution Approach 1:
The patent changes the physical and chemical parameters of the adhesive composition by incorporating specific monomers with different glass transition temperatures (Tg values). The first monomer has Tg of 95-120°C, the second has Tg of 60-90°C, the third has Tg of -35 to -25°C, and the fourth has Tg of -60 to -45°C. This multi-parameter approach to material composition achieves the desired hardness (Shore A ≥ 10) while maintaining bonding reliability under external impacts
Solution Approach 2:
The patent creates a composite adhesive material by combining multiple monomers with different Tg characteristics in specific ratios (first monomer: 35-65 wt%, second monomer: 15-25 wt%, third monomer: 15-25 wt%, fourth monomer: 5-15 wt%). This composite structure allows the adhesive layer to exhibit both high hardness for impact resistance and appropriate adhesion for substrate bonding, resolving the contradiction between strength and reliability
2Strength
If the adhesive layer hardness is increased to prevent substrate detachment, then bonding strength improves, but the adhesive layer may become too rigid to absorb external shocks
Solution Approach 1:
The patent utilizes the glass transition temperature parameter of monomers to create an adhesive layer with optimized mechanical properties. By selecting monomers with Tg values spanning from -60°C to 120°C and combining them in specific ratios, the adhesive achieves Shore A hardness ≥ 10 while maintaining sufficient flexibility to absorb external shocks without transmitting excessive force to the substrates
Solution Approach 2:
The patent applies local quality by having different monomer components contribute different properties to the adhesive layer. The first monomer (high Tg: 95-120°C) provides hardness and structural stability, while the third and fourth monomers (low Tg: -35 to -45°C) provide flexibility and shock absorption. This spatial and functional differentiation within the adhesive composition resolves the contradiction between hardness and impact resistance
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 adhesive layer prevents substrate detachment and crack formation by providing enhanced hardness and adhesion, ensuring the display device's structural integrity under external shocks and impacts.
Implementation Method 1
a photopolymerization initiator in an amount of about 1 wt % to about 5 wt %
Data Source
AI summary
Disclosed is a display device that includes: a display panel; a window on a surface of the display panel; and an adhesive layer between the display panel and the window. The adhesive layer may include an adhesive composition, the adhesive composition containing: a first polymer having a glass transition temperature (Tg) in a range of about 95° C. to about 120° C.; a second polymer having a glass transition temperature (Tg) in a range of about 60° C. to about 90° C.; a third polymer having a glass transition temperature (Tg) in a range of about −35° C. to about −25° C.; and a fourth polymer having a glass transition temperature (Tg) in a range of about −60° C. to about −45° C.