Optical Interference Layer Coating for Curved Surface Antireflection
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Solution Overview
Problem
Existing optical members with curved surfaces face significant deviations in antireflection performance due to thickness variations caused by vacuum film formation methods, leading to inconsistent reflection suppression, especially on surfaces with large half-opening angles.
Innovation Solution
A member with an optical interference layer composed of two layers, including a first layer and a porous layer containing inorganic compound particles, formed by a coating method to ensure consistent thickness distribution and improved adhesion, thereby enhancing antireflection performance regardless of substrate shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a vacuum film formation method is used to form the optical interference layer, then the film can be formed on the substrate, but the film thickness becomes non-uniform on curved surfaces with larger thickness at the central portion and smaller thickness at the periphery
Solution Approach 1:
The patent replaces the vacuum film formation method (physical vapor deposition) with a coating method (chemical deposition or solution-based coating). This substitution allows the optical interference layer to be formed uniformly on curved surfaces by controlling the coating process parameters such as coating speed, angle, and material viscosity, thereby achieving uniform film thickness regardless of substrate curvature.
2Shape
If a coating method is used to form the optical interference layer, then the film can be formed on curved surfaces, but the film thickness becomes non-uniform with larger thickness at the periphery and smaller thickness at the central portion
Solution Approach 1:
The patent optimizes coating parameters including coating speed, coating angle, material viscosity, and substrate rotation speed to achieve uniform film thickness distribution on curved surfaces. By carefully controlling these parameters, the coating method can accommodate curved surface geometry while maintaining manufacturing precision.
3Reliability
If the optical interference layer is designed for the central portion of the curved surface, then the antireflection performance is optimized at the center, but the peripheral portion has large deviation from optical design and insufficient reflection suppression
Solution Approach 1:
The patent designs the optical interference layer with position-dependent optical properties, where the refractive index and/or thickness vary across the surface from central to peripheral regions. This allows each region to be optimized for its specific incident angle and optical path, achieving consistent antireflection performance across the entire curved surface including regions with large half-opening angles.
4Reliability
If a multilayer structure with inorganic underlayer and surface modification layer is used, then the antireflection effect is enhanced, but the manufacturing complexity and process steps increase
Solution Approach 1:
The patent employs a multilayer optical interference structure comprising an inorganic underlayer and an organic surface modification layer with different refractive indices. This composite structure enhances the antireflection effect by creating optimal refractive index gradients, while the coating method maintains manufacturing feasibility by forming both layers in a single process sequence.
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 solution provides high antireflection performance across the entire surface, improving light transmittance and reducing flare and ghost effects in imaging systems, suitable for various optical elements and apparatuses.
Implementation Method 1
an optical interference layer that includes an inorganic underlayer formed of an inorganic material, a surface modification layer containing silicon oxide
Data Source
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Figure 3
AI summary
A member includes a substrate and an optical interference layer provided on at least one main surface side of the substrate and constituted by at least two layers, wherein the optical interference layer includes a first layer and a porous layer containing particles of an inorganic compound in this order from the substrate side.