UV-Absorbing Adhesive Sheet for Blister-Resistant Display Bonding
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Solution Overview
Problem
The production of electronic license plates with a coat layer to protect the display device increases costs and is prone to issues like blistering and delamination due to exposure to harsh environmental conditions.
Innovation Solution
An adhesive sheet with active energy ray curability and ultraviolet ray absorbability, which is cured by irradiation, providing both light resistance and blister resistance without the need for a separate coat layer, ensuring suitable interfacial adhesion and cohesive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coat layer containing ultraviolet ray absorber is provided on the cover material to achieve light resistance, then light resistance is improved, but production cost increases and device complexity increases
Solution Approach 1:
The patent combines the adhesive layer and ultraviolet ray absorber into a single integrated adhesive sheet. The adhesive layer itself contains the ultraviolet ray absorber, eliminating the need for a separate coat layer on the cover material. This merging of functions achieves light resistance while simplifying the overall structure and reducing production costs.
Solution Approach 2:
The adhesive sheet serves multiple functions simultaneously: it provides adhesion between the cover material and display device, contains ultraviolet ray absorbers for light resistance, and offers blister resistance through proper formulation. This multi-functionality eliminates the need for separate dedicated coat layers.
2Reliability
If the adhesive layer is made to have ultraviolet ray absorbability for light resistance, then light resistance is improved, but curability by active energy rays may be hindered
Solution Approach 1:
The patent applies local quality by having the ultraviolet ray absorber distributed within the adhesive layer at specific concentrations that provide light resistance while allowing active energy ray curing. The absorber is present in amounts sufficient for protection but controlled to not completely block curing radiation.
Solution Approach 2:
The patent optimizes parameters including the type and concentration of ultraviolet ray absorbers, the thickness of the adhesive layer, and the wavelength characteristics of the active energy rays used for curing. By adjusting these parameters, the system achieves both light resistance and adequate curability.
3Reliability
If the adhesive sheet is exposed to high temperature and high humidity conditions, then durability is tested, but outgassing occurs causing blisters and delamination
Solution Approach 1:
The patent employs beforehand cushioning by selecting adhesive materials and formulations that are pre-screened for low outgassing characteristics under high temperature and humidity conditions. The adhesive composition is designed to minimize gas generation and trapping that would lead to blisters and delamination during durability testing.
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 sheet achieves both light resistance and blister resistance, preventing delamination and blistering under severe conditions, thus enhancing the durability of electronic license plates.
Implementation Method 1
an adhesive layer composed of an adhesive having active energy ray curability and ultraviolet ray absorbability
Implementation Method 2
when one surface of the adhesive layer is irradiated with ultraviolet rays having a light amount of 2000 mJ/cm2 to cure the adhesive layer
Data Source
AI summary
An adhesive sheet including an adhesive layer composed of an adhesive having active energy ray curability and ultraviolet ray absorbability, wherein when one surface of the adhesive layer is irradiated with ultraviolet rays having a light amount of 2000 mJ/cm2 to cure the adhesive layer and an infrared absorption spectrum is then measured for the irradiated surface and non-irradiated surface, the maximum absolute value of absorbance is 0.0001 to 0.012 within a wavenumber range of 700 to 1000 cm−1 in a difference spectrum obtained by subtracting the infrared absorption spectrum of the non-irradiated surface from the infrared absorption spectrum of the irradiated surface, and when the adhesive layer is irradiated with ultraviolet rays having a light amount of 2000 mJ/cm2 to cure the adhesive layer, the difference in a gel fraction of the adhesive constituting the adhesive layer before and after the irradiation is from 5 to 50 points.