Hygroscopic Broadband Window with Protective Coatings

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Solution Overview

Problem

There is a need for broadband windows that can transmit electromagnetic radiation across multiple spectral bands, including near ultraviolet, visible, near infrared, shortwave infrared, mid-wave infrared, and longwave infrared, with minimal loss due to internal absorption and reflections, while being hygroscopic and water-soluble, which existing materials like diamond and potassium bromide fail to address effectively.

Innovation Solution

The development of a hygroscopic broadband optical window with non-water-soluble protective layers made from materials like potassium bromide, potassium chloride, and thin-film coatings to reduce surface reflections and protect against humidity, using mounts and seals for easy replacement, and structural support for enhanced strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If hygroscopic broadband window materials are used to achieve broad spectral transmission, then transmission across multiple spectral bands is improved, but the window becomes susceptible to water damage and degradation

Engineering Contradiction:

Improvespectral transmission rangeVSAvoidresistance to water damage

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent combines hygroscopic broadband window materials (such as potassium bromide, potassium chloride, or other salt crystals) with hydrophobic protective coatings to create a composite structure. The inner broadband material provides transmission across multiple spectral bands including visible, infrared, and ultraviolet ranges, while the outer hydrophobic coating layer protects against water damage, humidity, and environmental degradation, allowing the window to maintain both broad spectral adaptability and reliability in humid conditions

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces a hydrophobic protective coating as an intermediary layer between the hygroscopic broadband window material and the external environment. This coating acts as a mediator that prevents direct contact between water/moisture and the sensitive broadband material, thereby preserving the material's structural integrity and optical properties while maintaining its broad spectral transmission capabilities

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If broadband window materials with broad spectral transmission are used, then transmission across multiple spectral bands is improved, but internal absorption and reflection losses increase

Engineering Contradiction:

Improvespectral transmission rangeVSAvoidinternal absorption and reflection losses

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent optimizes the physical and chemical parameters of the broadband window material, such as controlling crystal purity, minimizing inclusions and defects, and selecting materials with appropriate refractive indices. These parameter changes reduce internal absorption by ensuring high material purity and minimizing scattering centers, while also reducing reflection losses by selecting materials with refractive indices that minimize Fresnel reflections at the air-material interface

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If expensive broadband window materials like diamond are used, then transmission across multiple spectral bands is improved, but cost and availability become problematic

Engineering Contradiction:

Improvespectral transmission rangeVSAvoidcost and availability

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive, difficult-to-manufacture broadband materials like diamond with cheaper, more readily available hygroscopic crystal materials such as potassium bromide (KBr), potassium chloride (KCl), or other salt crystals. These alternative materials can be grown as single crystals or pressed into transparent forms at lower costs and are more readily available from commercial suppliers, making broadband windows economically viable while maintaining their broad spectral transmission properties across visible, infrared, and ultraviolet ranges

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 inexpensive, replaceable broadband windows with low loss across a broad spectral range, offering protection from water and mechanical damage, and enabling larger apertures with reduced reflection losses compared to existing technologies.

Implementation Method 1

the layer has sufficient thickness to protect the hygroscopic window from water or water vapor

Methodology Applied

Scientific EffectPhysical barrier protection:

Implementation Method 2

thin-film coatings to reduce surface reflections

Methodology Applied

Scientific EffectOptical interference: Interference

Data Source

PatentUS10847853B1Broadband windows

Publication Date: 2020.11.24 WAVEFRONT RESEARCH INC

AI summary

Broadband windows that transmit light simultaneously across several spectral bands are disclosed.