Photocurable Adhesive Composition for Optical Displays
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Solution Overview
Problem
Current optically-transparent adhesives used in displays and touch panels have limitations such as low refractive index, poor light transmittance, and inadequate flow properties, leading to issues like reflection, bubbles, and undesirable visual effects like water ripples.
Innovation Solution
A photocurable adhesive composition comprising (meth)acrylate oligomers, mono- or multi-functional monomers, a photoinitiator, and a plasticizer with a refractive index of no less than 1.48, which provides improved flowability, softness, and high refractive index, allowing for better light transmittance and adhesion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If liquid optically clear adhesives are used to simplify the adhering process, then the adhering steps are simplified and reworkability is improved, but the light transmittance and refractive index are poor
Solution Approach 1:
The patent changes the refractive index parameter of the adhesive by incorporating specific plasticizers with high refractive indexes (1.48-1.65) into the adhesive composition, thereby improving light transmittance while maintaining the liquid adhesive's ease of application
Solution Approach 2:
The patent creates a composite adhesive system by combining (meth)acrylate oligomers, monomers, photoinitiators, and high refractive index plasticizers to achieve both good optical properties (refractive index 1.45-1.55) and ease of manufacture
2Strength
If optical adhesive tape is used to provide sufficient thickness, then adhesion strength is improved, but bubbles or wrinkles may generate and the process complexity increases
Solution Approach 1:
The patent uses liquid adhesive that can be applied in thin layers, eliminating the need for thick adhesive tapes. The liquid formulation allows for bubble-free application and simplifies the adhering process while maintaining adequate adhesion strength through proper composition design
Solution Approach 2:
The patent optimizes the viscosity and composition parameters of the liquid adhesive to achieve proper flow properties that prevent overflow during application while ensuring sufficient adhesion strength, eliminating the need for thick adhesive layers
3Strength
If common optically-transparent adhesive with refractive index of 1.4 to 1.45 is used, then the adhesive provides basic adhesion, but light reflection occurs and light transmittance is reduced
Solution Approach 1:
The patent directly addresses the refractive index parameter by incorporating plasticizers with high refractive indexes (1.48-1.65) into the adhesive composition, raising the overall refractive index to 1.45-1.55 to reduce light reflection and improve light transmittance while maintaining adhesion
Solution Approach 2:
The patent enhances the optical properties locally at the adhesive layer by selecting specific plasticizers with high refractive indexes, creating an optical matching layer that reduces reflection at the interface between optical devices and adhesive
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 composition achieves high light transmittance and refractive index, preventing reflection and visual defects, while being easy to coat and adhere, thus enhancing the aesthetic appearance of screens and simplifying the manufacturing process.
Implementation Method 1
a photocurable adhesive composition comprising: a) a (meth)acrylate oligomer having one or more functional groups, b) a mono-functional monomer, a multi-functional monomer, or a mixture thereof, c) a photoinitiator
Data Source
AI summary
A photocurable adhesive composition is provided, which comprises: a) a (meth)acrylate oligomer having one or more functional groups, b) a mono-functional monomer, a multi-functional monomer, or a mixture thereof, c) a photoinitiator, and d) a plasticizer having a refractive index of no less than 1.48. The photocurable adhesive composition of the present invention has good light transmittance, high refractive index and appropriate flowability and softness, and is easy to be coated and adhered. The photocurable adhesive composition of the present invention can be applied to optical products and simplify the manufacture processes, and provide adhesion property while retaining good reworkability and optical properties.