Cover Glass Adhesive Elastic Modulus for Crack Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In-vehicle display devices face issues with low crack resistance at the edge portions of cover glass, leading to floating glass fragments and display unevenness during cracking.
Innovation Solution
A display device configuration featuring a cover glass with a chemically strengthened glass substrate, a frame, and adhesive layers with specific elastic moduli to prevent cracking and fragment floating, including a first adhesive layer with an elastic modulus of 5 MPa or more and 400 MPa or less, and a second adhesive layer with a lower elastic modulus, ensuring effective adhesion and preventing display unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cover glass is used to protect the display device, then protection and durability are improved, but crack resistance at edge portions deteriorates due to latent scratches
Solution Approach 1:
The patent applies beforehand cushioning by providing a buffer layer between the cover glass and the adhesive layer. This buffer layer absorbs and distributes stress concentrations that would otherwise propagate cracks from latent scratches at the edge portions, thereby maintaining protection capability while improving crack resistance
Solution Approach 2:
The patent uses composite materials by combining the cover glass with a specifically designed adhesive layer having controlled elastic modulus. This composite structure allows the adhesive layer to compensate for stress concentrations at the edges, preventing crack propagation while maintaining the protective function of the cover glass
2Reliability
If adhesive strength is increased to prevent floating of glass fragments, then safety is improved, but display unevenness occurs due to rigid adhesion
Solution Approach 1:
The patent applies parameter changes by precisely controlling the elastic modulus of the adhesive layer within a specific range. This allows the adhesive to maintain sufficient strength to prevent floating of glass fragments while having enough flexibility to accommodate thermal expansion and contraction, thereby preventing display unevenness
Solution Approach 2:
The patent applies local quality by designing the adhesive layer with specific local properties - sufficient adhesion strength at the bonding interface to prevent fragment floating, while maintaining appropriate flexibility in the bulk to allow for dimensional changes without causing display unevenness
3Manufacturing precision
If adhesive elasticity is increased to prevent display unevenness, then display uniformity is improved, but adhesive strength decreases allowing glass fragment floating
Solution Approach 1:
The patent resolves this contradiction by optimizing the elastic modulus parameter of the adhesive layer to a specific range. This balanced parameter selection ensures that the adhesive has sufficient strength to prevent glass fragment floating while maintaining enough elasticity to accommodate thermal and mechanical stresses, thereby preventing display unevenness
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 solution effectively prevents display unevenness and reduces glass fragment floating during cracking by maintaining the necessary adhesive strength and flexibility, enhancing the durability of the in-vehicle display device.
Implementation Method 1
the first adhesive layer has an elastic modulus of 5 MPa or more and 400 MPa or less in an indentation elastic modulus test
Data Source
AI summary
The present invention relates to a display device including: a display panel; a frame including a portion provided outside the display panel; a cover glass including a first main surface and a second main surface, the cover glass being provided on or above the display panel and the frame such that the second main surface faces the display panel and the frame; and a first adhesive layer provided between the second main surface of the cover glass and the frame, the first adhesive layer adhering the second main surface of the cover glass and the frame to each other, in which the first adhesive layer has an elastic modulus of 5 MPa or more and 400 MPa or less in an indentation elastic modulus test.