Optical Sheet Functional Layer with Metal Oxide Reinforcement
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Solution Overview
Problem
Existing optical sheets with hollow silica particles suffer from inadequate abrasion resistance due to the fragility and detachment of these particles, leading to surface damage during use.
Innovation Solution
Incorporating metal oxide particles into the functional layer of the optical sheet, along with a controlled arithmetical mean roughness of 5.2 nm or less, enhances the abrasion resistance by improving the strength and hardness of the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If hollow silica particles are used in the functional layer to reduce refractive index, then the reflection-reducing function is improved, but the abrasion resistance deteriorates due to particle breakage and detachment
Solution Approach 1:
The patent combines hollow silica particles with metal oxide particles (such as alumina, silica, or titania) to form a composite functional layer. The metal oxide particles act as a protective matrix that embeds the hollow silica particles, preventing their breakage and detachment while maintaining the low refractive index property. This composite structure resolves the contradiction by providing both the optical function and mechanical durability.
Solution Approach 2:
The metal oxide particles serve as an intermediary protective layer between the hollow silica particles and the external environment. This intermediary structure protects the fragile hollow silica particles from mechanical stress and abrasion, allowing them to maintain their reflective properties without detaching or breaking during use.
2Reliability
If inorganic oxide particles are added to form projections on the surface to protect hollow silica particles, then abrasion resistance is improved, but surface roughness increases
Solution Approach 1:
The patent carefully controls the particle size parameters of the metal oxide particles, specifying that they range from 1 nm to 100 nm with an average particle diameter of 10 nm to 50 nm. By optimizing these size parameters, the metal oxide particles provide protective function without creating large surface projections, thus maintaining smooth surface finish while improving abrasion resistance.
Solution Approach 2:
The metal oxide particles are distributed throughout the functional layer at a specific concentration (1 wt% to 50 wt%), providing localized protection to hollow silica particles throughout the layer thickness. This distributed local protection approach prevents surface projections while maintaining overall abrasion resistance through uniform reinforcement of the functional layer structure.
Data Source
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AI summary
An optical sheet is an optical sheet having a first surface and a second surface opposite the first surface. The optical sheet includes a substrate and a functional layer in order from the second surface toward the first surface. The functional layer contains a binder resin, hollow silica particles, and metal oxide particles other than silica particles. The arithmetical mean roughness Sa on the first surface is 5.2 nm or less.