Multilayer AR Coating UV IR Reflectance Reduction

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Solution Overview

Problem

Conventional anti-reflective (AR) coatings on eyeglass lenses do not effectively reduce reflectance in the UV and IR spectral bands, which can be harmful to eye health, while maintaining optimal visible light transmission and glare reduction.

Innovation Solution

A multilayer AR coating comprising high refractive index (HighIndex) and low refractive index (LowIndex) materials, specifically ZrO2 and SiO2, is applied to the backside of lenses, with a configuration that includes a final LowIndex layer and a penultimate HighIndex layer, along with additional layers for scratch resistance and hydrophobic properties, to minimize UV and IR reflectance while maintaining low visible light reflectance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional anti-reflective coatings are applied to reduce visible light reflection, then visible light transmission is improved, but UV and IR reflectance remains high which is harmful to eye health

Engineering Contradiction:

Improvevisible light transmissionVSAvoidUV and IR reflectance

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The AR coating is divided into multiple distinct layers, each optimized for specific spectral ranges. The multilayer structure includes layers with different refractive indices and thicknesses designed to target different wavelength bands (UV, visible, IR) independently, allowing simultaneous optimization of visible light transmission and UV/IR reflectance reduction

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The coating uses composite material structure combining multiple materials with different optical properties (different refractive indices). This includes alternating layers of high and low refractive index materials, and potentially incorporates specialized materials like fluorinated compounds for UV protection and metal oxides for IR management, creating a composite system that addresses multiple spectral bands simultaneously

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If multilayer AR coating with specific thicknesses is applied, then UV and IR reflectance is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

ImproveUV and IR reflectance reductionVSAvoidcoating layer thickness control

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent specifies precise parameter ranges for layer thicknesses (e.g., first layer 5-20 nm, second layer 20-50 nm, third layer 50-100 nm) and refractive indices to optimize the balance between UV/IR reflectance reduction and manufacturing feasibility. These parameter specifications provide clear manufacturing targets while maintaining effectiveness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The coating design uses relatively thin layers (especially the first fluorinated layer at only 5-20 nm) to achieve UV protection, which reduces the total coating thickness and simplifies manufacturing precision requirements compared to thicker conventional coatings. This partial action approach focuses thickness on where it's most needed

Inventive Principle:

Principle #16Partial or excessive action

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 achieves a significant reduction in UV and IR reflectance, providing full-spectrum protection by limiting backside reflectance to less than 13% in the UV range and 14% in the IR range, while maintaining low visible light reflectance, thus safeguarding eye health.

Implementation Method 1

A multilayer AR coating comprising high refractive index (HighIndex) and low refractive index (LowIndex) materials, specifically ZrO2 and SiO2, is applied to the backside of lenses

Methodology Applied

Scientific EffectOptical interference: Interference

Implementation Method 2

the HighIndex material has a refractive index of at least 1.6 and the LowIndex material has a refractive index of no greater than 1.5

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS20220043186A1Visible Spectrum Anti-Reflective Coatings with Reduced Reflections in Ultraviolet and Infrared Spectral Bands

Publication Date: 2022.02.10 I COAT CO LLC

AI summary

Lens coatings and coated lenses which offer full-spectrum protection by reducing back-side reflection of all light spanning from the ultraviolet sub-band B (UVB) to infrared (IR-A) region are provided. The full-spectrum back-side anti-reflective coatings disclosed herein are comprised of multiple thin-film layers of high refractive index (HighIndex) and low refractive index (LowIndex) materials. In many embodiments, the penultimate layer distal from the substrate lens is a HighIndex layer, and the final layer distal from the substrate lens is a LowIndex layer.