Multi-Structured Display Film for Optical Interference Fringe Control
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Solution Overview
Problem
Polymer films used as cover windows in display devices suffer from optical interference fringes due to differences in optical properties between the substrate and coating layer, leading to deteriorated visibility.
Innovation Solution
A film with a reflectance oscillation ratio (O r ) of 1.0 or less and a reflectance graph slope (G r ) of 0.122 or less is achieved by controlling the refractive index and thickness of coating layers using transparent polymers and dispersed particles, ensuring uniform light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating layer is formed on a polymer substrate to improve physical properties such as hardness and abrasion resistance, then the mechanical strength and durability are improved, but optical interference fringes occur due to differences in optical properties between the coating layer and substrate, deteriorating visibility
Solution Approach 1:
A buffer layer is introduced between the coating layer and the polymer substrate to serve as an optical intermediary. This buffer layer has optical properties (refractive index) that are intermediate between those of the coating layer and the substrate, thereby reducing the optical contrast and minimizing interference fringes while allowing the coating layer to maintain its protective mechanical functions
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers (coating layer, buffer layer, and substrate) with different material properties. The buffer layer is specifically designed with composite characteristics that balance mechanical support and optical compatibility, creating a multi-functional layered composite material system
2Reliability
If the thickness and refractive index of the coating layer are increased to enhance protective properties, then mechanical durability is improved, but the reflectance oscillation ratio and interference fringe visibility increase, deteriorating optical quality
Solution Approach 1:
The patent optimizes specific parameters including the thickness of the buffer layer (set to 1-10 times the coating layer thickness) and the refractive index of the buffer layer (selected to be between 1.3-1.7) to achieve the desired balance between protective properties and optical quality. These parameter adjustments minimize the reflectance oscillation ratio and eliminate visible interference fringes
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 film effectively prevents interference fringes, enhancing visibility and protecting the display surface with improved optical and mechanical properties.
Implementation Method 1
optical interference occurs in the film including the coating layer formed on the substrate due to the difference in optical properties between the coating layer and the substrate
Implementation Method 2
adjusting the reflectance oscillation ratio Or of the film to 1.0 or less and the reflectance graph slope Gr of the film to 0.122 or less
Data Source
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AI summary
The present invention provides a film comprising: a substrate; and a first coating layer on the substrate, wherein the film has, from a reflectance graph obtained by measuring the reflectance in a 380 nm to 780 nm wavelength region, a reflectance oscillation ratio (Or) of 1.0 or less and a reflectance graph slope (Gr) of 0.122 or less, and has improved interference fringes.