UV-Blocking Optically Clear Adhesive for Display Lamination
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Solution Overview
Problem
Current optically clear adhesives (OCAs) for display devices do not effectively block UV radiation, leading to degradation of organic components, especially in outdoor environments, and existing solutions suffer from issues like shrinkage and uneven adhesive layers during UV curing.
Innovation Solution
A UV-blocking OCA composition comprising a pressure-sensitive adhesive mixed with a package of UV absorbers, including hydroxyphenyl benzotriazole, benzophenone, and hindered amine light stabilizers, which absorbs over 90% of UV transmission below 380 nm while maintaining high transparency above 410 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a UV blocking layer is added to block UV radiation, then UV protection is improved, but optical clarity in the visible light range deteriorates
Solution Approach 1:
The adhesive composition is designed to have different optical properties at different wavelength ranges: high UV absorption (blocking harmful UV radiation below 380nm) while maintaining high visible light transmission (greater than 90% above 410nm). This local differentiation of optical properties resolves the contradiction between UV protection and visual clarity.
Solution Approach 2:
The patent combines pressure-sensitive adhesive materials with specific UV absorbers (hydroxyphenyl benzotriazole, benzophenone) and hindered amine light stabilizers to create a composite adhesive material that simultaneously provides bonding functionality, UV protection, and optical clarity. This composite approach allows multiple functions to coexist without compromising each other.
2Object-affected harmful factors
If UV absorbers are added to the adhesive composition, then UV blocking capability is improved, but adhesive performance deteriorates
Solution Approach 1:
The patent carefully controls the concentration parameters of UV absorbers (0.1-5% hydroxyphenyl benzotriazole, 0.1-5% benzophenone, 0.1-5% hindered amine light stabilizer) within the adhesive composition. By optimizing these parameter ranges, the formulation achieves sufficient UV blocking (greater than 90% UV absorption below 380nm) while maintaining the pressure-sensitive adhesive's bonding reliability through proper formulation balance.
3Object-affected harmful factors
If a broad-spectrum UV blocking adhesive is developed, then UV protection coverage is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple UV protection functions into a single adhesive layer by combining different types of UV absorbers (hydroxyphenyl benzotriazole for UVB protection, benzophenone for broad-spectrum protection) and hindered amine light stabilizers. This consolidation provides comprehensive UV protection (blocking UV A, B, and C bands) in one material rather than requiring multiple separate layers, thereby reducing overall system complexity.
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 provides excellent UV stability and optical clarity, preventing degradation of display devices by effectively blocking harmful UV radiation while ensuring transparency in the visible light range, thus enhancing the durability and image quality of electronic displays.
Implementation Method 1
the cured adhesive has a percent transmittance of less than 10% at 380 nm or less, and a percent transmittance greater than 90% at 410 nm or greater
Implementation Method 2
about 0.1 to about 5% hindered amine light stabilizer
Data Source
AI summary
Optically clear adhesives (OCA) with UV blocking below 380 nm are described. The OCA comprise a UV blocking package of UV absorbers and hindered amine light stabilizers. The UV blocking package is suitable for a variety of OCA, including PIB-based OCA, styrenic block copolymer-based OCA, silicone-based OCA, or acrylic-based OCA. The OCA with UV blocking in the invention are particularly suitable as laminating films, tapes or encapsulants for adhering display electronic devices, e.g., LCD displays, LED displays, flexible and foldable displays, and touch screens.