Optical Laminate Structure 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 thicknesses, enhances resistance to surface pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the light absorption anisotropic layer is made thin to reduce overall laminate thickness, then the display device becomes more suitable for folded/wound applications, but the layer becomes more susceptible to deformation under stylus pressure
Solution Approach 1:
The patent changes the parameter of indentation elastic modulus by selecting a pressure sensitive adhesive layer with specific material properties (indentation elastic modulus of 10 MPa or more) to protect the thin light absorption anisotropic layer from deformation under stylus pressure while maintaining the thin overall structure
Solution Approach 2:
The patent uses a composite structure combining a surface protective layer, a pressure sensitive adhesive layer with specific elastic properties, and a thin light absorption anisotropic layer to achieve both thinness and pressure resistance
2Reliability
If a surface protective layer is added to protect against stylus pressure, then resistance to surface pressure improves, but the overall laminate thickness increases
Solution Approach 1:
The patent optimizes the thickness parameter of the surface protective layer to 1 μm or more (preferably 1 to 10 μm) to provide sufficient pressure resistance while minimizing the increase in overall laminate thickness
Solution Approach 2:
The patent uses a thin film structure for the surface protective layer (1 μm or more) that provides pressure resistance while maintaining flexibility and minimizing thickness increase, suitable for folded/wound display devices
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
An optical laminate used for a display device having excellent resistance to the pressure from the surface and a display device including the same. The optical laminate includes a first pressure sensitive adhesive layer, a light absorption anisotropic layer, and a second pressure sensitive adhesive layer in this order from a viewing side of the display device, 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 contains a dichroic substance, and a thickness of the second pressure sensitive adhesive layer is in a range of 5 to 50 μm.