Mirror-Coated Lens Optical Interference Design
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Solution Overview
Problem
Conventional mirror-coated lenses face issues with low transmittance, leading to glare and flare phenomena, while attempts to increase transmittance by reducing metal layer thickness result in decreased clarity of vision due to reflection from the back surface.
Innovation Solution
A mirror-coated lens design featuring a functional film on the front surface with a low refractive index layer, high refractive index layer, and metal layer, and a similar film on the back surface, optimizing luminous reflectance and transmittance to suppress glare and flare phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of the metal layer is reduced to increase transmittance, then the transmittance is increased, but conspicuous glare and flare phenomenon and ghost phenomenon occur
Solution Approach 1:
The patent applies composite materials by combining multiple layers with different optical properties: a low refractive index layer (SiO2, n=1.46), a high refractive index layer (TiO2, n=2.64), and a metal layer (Al, Ag, or Au). This composite structure creates constructive and destructive interference patterns that control light reflection and transmission, achieving high transmittance while suppressing glare and flare phenomena through optimized layer thicknesses and refractive index contrasts.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the thickness of each layer (low refractive index layer: 50-200 nm, high refractive index layer: 50-200 nm, metal layer: 5-50 nm) and selecting specific refractive indices to optimize the optical performance. By adjusting these parameters, the lens achieves high luminous transmittance (80-90%) while minimizing harmful reflections and flare effects.
2Illumination intensity
If the thickness of the metal layer is reduced to increase transmittance, then the transmittance is increased, but the clarity of vision is decreased due to reflection from the back surface
Solution Approach 1:
The patent uses a composite multilayer structure consisting of a low refractive index layer, a high refractive index layer, and a metal layer. This composite design creates controlled optical interference that reduces back-surface reflections while maintaining high forward transmittance, thereby preserving clarity of vision even with reduced metal layer thickness.
Solution Approach 2:
The patent applies local quality by assigning different functions to different layers: the low refractive index layer and high refractive index layer work together to control reflection at specific interfaces, while the metal layer provides the mirror coating function. This localized functional distribution allows the system to achieve both high transmittance and clear vision by optimizing each layer's contribution.
3Object-affected harmful factors
If a lens base material is colored to suppress reflection from the back surface, then the reflection is reduced, but the transmittance is largely decreased
Solution Approach 1:
Instead of coloring the lens base material, the patent uses a composite multilayer functional film structure on the back surface consisting of a low refractive index layer and a high refractive index layer. This composite optical coating suppresses back surface reflection through controlled interference without absorbing light, thereby maintaining high luminous transmittance while reducing unwanted reflections.
Solution Approach 2:
The patent replaces the chemical approach (coloring the lens base material to reduce reflection) with an optical approach (using a multilayer interference coating). This substitution eliminates light absorption associated with coloring and uses purely optical interference mechanisms to suppress reflection, preserving high transmittance.
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 design achieves high transmittance while effectively reducing glare and flare phenomena, enhancing visibility and clarity of vision.
Implementation Method 1
a functional film (C1) containing a low refractive index layer, a high refractive index layer, and a metal layer on a front surface of the lens base material; and a functional film (C2) containing a low refractive index layer and a high refractive index layer on a back surface of the lens base material
Implementation Method 2
a low refractive index layer, a high refractive index layer
Implementation Method 3
a metal layer on a front surface of the lens base material... luminous reflectance on the front surface side is from 3 to 30%
Data Source
AI summary
Provided is a mirror-coated lens having a high transmittance and capable of suppressing a flare phenomenon and a ghost phenomenon. The mirror-coated lens includes a lens base material, a functional film (C1) containing a low refractive index layer, a high refractive index layer, and a metal layer on a front surface of the lens base material, and a functional film (C2) containing a low refractive index layer and a high refractive index layer on a back surface of the lens base material. The luminous reflectance on the front surface side is from 3 to 30%, the transmittance of the eyeglass lens is from 55 to 80%, and the luminous reflectance on the back surface side is from 0.1 to 9%.