Optical Laminate Modulus Layering for Stylus Pressure Resistance
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Solution Overview
Problem
Display devices with optical laminates experience degradation of display performance due to deformation of the light absorption anisotropic layer caused by pressure from stylus pens, as existing optical laminates lack sufficient resistance to surface pressure.
Innovation Solution
An optical laminate configuration with a surface protective layer, a first pressure sensitive adhesive layer with higher indentation elastic modulus than the light absorption anisotropic layer, and a thickness of the anisotropic layer less than 5 μm, along with specific adhesive and layer thickness specifications, enhances resistance to surface pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the light absorption anisotropic layer is reduced to less than 5 μm to achieve a thinner optical laminate, then the overall thickness is reduced, but the resistance to surface pressure deteriorates causing deformation under stylus pen pressure
Solution Approach 1:
The patent uses a composite pressure sensitive adhesive layer combining a first pressure sensitive adhesive and a second pressure sensitive adhesive with different properties. The first adhesive provides bonding functionality while the second adhesive with higher storage elastic modulus provides mechanical support and pressure resistance. This composite structure allows the thin light absorption anisotropic layer (less than 5 μm) to maintain both thinness and sufficient resistance to surface pressure through the synergistic combination of different adhesive materials.
Solution Approach 2:
The patent changes the key parameter of storage elastic modulus by introducing a second pressure sensitive adhesive with higher storage elastic modulus than the first adhesive. This parameter change in the adhesive layer's mechanical properties provides the necessary support to prevent deformation of the thin light absorption anisotropic layer under surface pressure, while maintaining the overall thin structure of the optical laminate.
2Ease of manufacture
If a pressure sensitive adhesive layer is used to bond the surface protective layer to the light absorption anisotropic layer, then assembly is simplified, but the resistance to surface pressure is insufficient causing deformation under stylus pen pressure
Solution Approach 1:
The patent applies a composite pressure sensitive adhesive layer consisting of two different pressure sensitive adhesives with distinct functional characteristics. The first pressure sensitive adhesive provides ease of bonding and assembly, while the second pressure sensitive adhesive with higher storage elastic modulus provides the necessary mechanical strength and resistance to surface pressure. This composite approach maintains the simplicity of pressure-sensitive bonding while overcoming the insufficiency of single-adhesive structures in providing adequate pressure resistance.
Solution Approach 2:
The patent applies different properties of pressure sensitive adhesives at different positions or functions within the same adhesive layer system. The first pressure sensitive adhesive is optimized for bonding capability, while the second pressure sensitive adhesive is optimized for mechanical support and pressure resistance. This local differentiation of adhesive properties allows the system to simultaneously achieve ease of manufacture and sufficient resistance to surface pressure.
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 laminate provides excellent resistance to surface pressure, preventing deformation of the light absorption anisotropic layer and maintaining display performance.
Implementation Method 1
an indentation elastic modulus of the first pressure sensitive adhesive layer is greater than an indentation elastic modulus of the light absorption anisotropic layer
Data Source
AI summary
Provided is an optical laminate having excellent resistance to the pressure from the surface and a display device including the same. The optical laminate includes a surface protective layer, a first pressure sensitive adhesive layer, a light absorption anisotropic layer, and a second pressure sensitive adhesive layer in this order, in which an indentation elastic modulus of the first pressure sensitive adhesive layer is greater than an indentation elastic modulus of the light absorption anisotropic layer, the light absorption anisotropic layer is a layer formed of a composition for forming a light absorption anisotropic layer containing a liquid crystal compound and a dichroic substance, and a thickness of the light absorption anisotropic layer is less than 5 μm.