Interference Coating for Homogeneous Red Residual Reflection
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Solution Overview
Problem
Existing ophthalmic lenses with anti-reflective coatings struggle to achieve a homogeneous red residual reflection color, as existing coatings often appear orange or pink, and are difficult to reproduce due to variability in deposition conditions.
Innovation Solution
An ophthalmic lens with an interference coating having a hue angle of 0° to 40° and a Chroma value greater than or equal to 20, comprising a stack of specific physical thickness layers with high and low refractive indices, ensuring a perceived red residual reflection color that is consistent and reproducible across curved surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If existing anti-reflective coatings are used to reduce visible reflection, then the reflection factor is reduced, but the residual color appears orange or pink instead of homogeneous red
Solution Approach 1:
The patent applies parameter changes by precisely controlling the physical thickness of each layer in the interference stack. The specific thickness ranges (100-120 nm for first high index layer, 110-140 nm for first low index layer, 75-95 nm for second high index layer, 55-77 nm for second low index layer) are optimized to achieve the desired red residual reflection color while maintaining low visible reflection. This precise parameter control transforms the coating's optical properties to resolve the color uniformity issue.
Solution Approach 2:
The patent uses composite materials by combining multiple layers of alternating high and low refractive index materials. This multi-layer interference stack creates constructive and destructive interference patterns that produce the desired red residual reflection while minimizing overall visible reflection. The composite structure of four distinct layers with specific thicknesses enables simultaneous achievement of low reflection and homogeneous red color.
2Ease of operation
If anti-reflective coatings are applied to improve gaze visibility and comfort, then reflection and glare are reduced, but the residual color perception varies between lenses due to deposition variability
Solution Approach 1:
The patent addresses color reproducibility through parameter changes by defining specific thickness ranges for each layer that are robust to deposition variability. The optimized thickness parameters create a tolerance window that maintains consistent red color perception across different lenses manufactured under varying conditions, thereby improving reliability without sacrificing gaze visibility benefits.
Solution Approach 2:
The interference stack design achieves universality by creating a coating structure that simultaneously provides multiple functions: reducing visible reflection, eliminating glare, improving contrast perception, and ensuring homogeneous red color consistency across all lenses. This multi-functional design makes the coating universally applicable while maintaining reliable color reproduction.
3Manufacturing precision
If the hue angle is set to achieve red color perception, then the residual reflection appears red, but achieving homogeneous color across curved surfaces becomes difficult
Solution Approach 1:
The patent resolves the curvature issue through parameter changes by optimizing the absolute thickness values of all four layers. This specific thickness configuration compensates for the optical path differences caused by surface curvature, ensuring that the interference conditions for red color perception remain consistent across flat and curved surfaces, thereby achieving homogeneous color appearance.
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 achieves a homogeneous red residual reflection color that is stable and reproducible, overcoming the challenges of achieving a red hue in ophthalmic lenses, even under varying deposition conditions, and maintains a low visible reflection value.
Implementation Method 1
comprising an interference stack having a perceived chromatic color of homogeneous residual reflection
Implementation Method 2
whose perceived chromatic color of residual reflection is homogeneous red coloring
Implementation Method 3
at least one of these two main faces comprises an interference stack, in particular an anti-reflection stack
Implementation Method 4
to reduce the average reflection factor in the visible
Data Source
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AI summary
The present invention relates to a transparent article comprising a substrate comprising at least one front face and one back face, at least one of these two main faces being coated with an interference coating having a reflection value in the visible Rv lower than or equal to 97% and preferably lower than or equal to 50%, characterized in that said interference coating possesses a hue angle h and a chroma value C* able to render the present residual reflection a given perceived chromatic colour in the red.