Multilayer Antireflection Coating for Selective Blue Light Reflection
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Solution Overview
Problem
Current optical lenses fail to provide adequate protection against harmful blue light, especially from LED digital devices, while maintaining good visibility and comfort, as they either filter too little blue light or compromise antireflection performance and circadian rhythm regulation.
Innovation Solution
A multilayer antireflection coating with a high refractive index layer and a low refractive index layer, designed to reflect a significant portion of blue light in the 440-460 nm range while minimizing reflection at lower wavelengths, ensuring high transparency and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a traditional antireflection coating is used to minimize light reflection, then visibility and visual comfort are improved, but protection against harmful blue light is insufficient
Solution Approach 1:
The coating is divided into multiple functional layers with different refractive indices (high refractive index layer and low refractive index layer), where each layer serves a specific purpose in reflecting or transmitting different wavelengths of light. This segmentation allows the coating to selectively reflect harmful blue light while maintaining antireflection performance for visible light.
Solution Approach 2:
The coating applies different optical properties to different wavelength ranges: the high refractive index layer (≥1.55) and low refractive index layer (≤1.55) are designed with specific thicknesses and refractive indices to create constructive interference for blue light reflection (440-460 nm) while maintaining destructive interference for visible light transmission.
2Object-affected harmful factors
If blue light filtering is increased to protect against phototoxic effects, then retinal protection is improved, but circadian rhythm regulation is compromised
Solution Approach 1:
The coating parameters (refractive index, layer thickness) are precisely optimized to create a reflection peak centered at 450 nm with a full width at half maximum of 20-40 nm. This narrow bandwidth selectively reflects harmful blue light (440-460 nm) while transmitting beneficial blue light (465-495 nm) needed for circadian rhythm regulation.
Solution Approach 2:
The coating provides different optical functions for different wavelength ranges: strong reflection for harmful blue light (440-460 nm) and high transmission for beneficial blue light (465-495 nm) and visible light, thereby simultaneously achieving phototoxic protection and circadian rhythm preservation.
3Object-affected harmful factors
If a multilayer coating structure is implemented to reflect blue light, then blue light protection is improved, but manufacturing complexity increases
Solution Approach 1:
The invention extracts and optimizes the essential functional elements needed for blue light reflection: a high refractive index layer (≥1.55) and a low refractive index layer (≤1.55) with specifically controlled thicknesses. This simplified multilayer structure achieves the desired optical performance without requiring excessive layers, balancing protection effectiveness with manufacturing feasibility.
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 coating effectively reduces blue light exposure, enhancing visual comfort and protecting against phototoxic effects while maintaining good antireflection performance and preserving circadian rhythm regulation.
Implementation Method 1
a multilayer antireflection coating comprising a stack of at least one high refractive index layer having a refractive index higher than 1.55 and at least one low refractive index layer having a refractive index of 1.55 or less
Implementation Method 2
the multilayer antireflection coating provides the optical lens with an average blue light reflection factor RmB3 within a wavelength range of from 440 nm to 460 nm, which is higher than or equal to 15%
Data Source
AI summary
Disclosed is an optical lens including a substrate having a front main face and a rear main face, at least one of the main faces including a multilayer antireflection coating having a stack of at least one high refractive index layer and at least one low refractive index layer, wherein the multilayer antireflection coating(s) present on the main face(s) provide(s) the optical lens with an average blue light reflection factor RmB3 within the wavelength range 440-460 nm, which is higher than or equal to 15%, for an angle of incidence ranging from 0° to 15°, and the spectral reflectivity curve of the multilayer antireflection coating has a reflection peak centered at a wavelength in the 340-420 nm range, and the reflection peak has a maximum reflectivity lower than or equal to 50% and exhibits a full width at half maximum higher than 70 nm.