Non-Planar Substrate Optical Coating Thickness Variation
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Solution Overview
Problem
Conventional coated articles with optical coatings on non-planar substrates face challenges in achieving abrasion resistance, scratch resistance, and improved optical performance, as the presence of optical coatings can compromise the mechanical strength and optical properties, particularly on curved surfaces where coating thickness and angle variations affect reflectance and color consistency.
Innovation Solution
A coated article design featuring a substrate with non-planar surfaces, where the optical coating has varying thicknesses to maintain low reflectance and color consistency across different angles, incorporating a scratch-resistant layer and alternating high and low refractive index layers, optimized for line-of-sight deposition processes to accommodate curvature and ensure robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If optical coatings are applied to non-planar substrates, then optical performance is improved, but mechanical strength is reduced
Solution Approach 1:
The patent applies parameter changes by modifying the coating thickness distribution across the non-planar substrate surface. The coating thickness is varied to compensate for the curvature-induced optical path differences, maintaining consistent optical performance while preserving mechanical strength through optimized material distribution.
Solution Approach 2:
The patent uses composite materials by combining multiple coating layers with different refractive indices and mechanical properties. This multi-layer composite structure achieves both the desired optical performance and enhanced mechanical strength, resolving the contradiction between optical improvement and strength preservation.
2Reliability
If optical coatings are applied to non-planar substrates, then scratch resistance is improved, but coating thickness uniformity deteriorates
Solution Approach 1:
The patent applies local quality by making the coating thickness location-dependent across the non-planar substrate. Different regions of the substrate receive coatings with locally optimized thickness values, ensuring scratch resistance while compensating for the non-uniform surface geometry through spatially varying coating parameters.
3Illumination intensity
If conventional anti-reflective coatings are used, then reflectance is reduced, but abrasion resistance deteriorates
Solution Approach 1:
The patent resolves this contradiction by using composite materials in the form of multi-layer coatings with different refractive indices and hardness values. The composite structure achieves low reflectance through optical interference while the harder outer layers provide abrasion resistance, combining optical and mechanical benefits.
Solution Approach 2:
The patent applies parameter changes by varying the refractive index, thickness, and composition parameters of different coating layers. This optimization allows the coating system to simultaneously achieve low reflectance and high abrasion resistance by tuning the physical and optical parameters of each layer.
4Stability of the object's composition
If coating thickness is reduced on curved portions, then optical consistency is improved, but coating coverage deteriorates
Solution Approach 1:
The patent applies local quality by adjusting coating thickness locally across different regions of the non-planar substrate. Areas with higher curvature receive thinner coatings while flatter areas receive thicker coatings, maintaining optical consistency through local optimization rather than uniform thickness.
Solution Approach 2:
The patent uses parameter changes by varying the coating thickness parameter as a function of surface curvature. This continuous parameter adjustment ensures optimal optical performance across the entire non-planar surface while maintaining adequate coating coverage where needed.
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 a coated article with enhanced mechanical strength, low reflectance, and neutral color appearance across various viewing angles, maintaining optical performance and resistance to abrasion and scratches on non-planar surfaces.
Implementation Method 1
The optical coating may form an anti-reflective surface... exhibit a single side light reflectance of about 3% or less at all wavelengths from 410 nm to at least 1050 nm
Implementation Method 2
optimized for line-of-sight deposition processes to accommodate curvature and ensure robustness
Data Source
AI summary
Articles are described that may include substrates having a major surface, the major surface comprising a first portion and a second portion. A first direction that is normal to the first portion of the major surface may not be equal to a second direction that is normal to the second portion of the major surface. The angle between the first direction and the second direction may be at least 15 degrees. An optical coating may be disposed on at least the first portion and the second portion of the major surface. The optical coating may form an antireflective surface.