Optical Layered Structure for High-Temperature Emission

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Solution Overview

Problem

Existing optical layered structures for emitter use face challenges with stability and high-temperature durability, limiting their efficiency and longevity, especially when compared to detector applications.

Innovation Solution

A layered structure comprising a reflecting layer, a partly transparent layer, and an intermediate layer, with a protecting layer, designed to maintain stability and high emissivity at elevated temperatures, allowing for efficient emission, absorption, and reflection of electromagnetic radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a simple single-material component is used for emission, then the manufacturing is simple, but the emissivity is low and efficiency is poor

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidemissivity
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent applies composite materials by stacking multiple layers with different materials (e.g., silicon nitride, silicon oxide, tungsten, molybdenum) to achieve high emissivity in the mid-wavelength infrared range. This layered composite structure enables selective thermal radiation while maintaining manufacturability through standard semiconductor fabrication processes.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If a known absorber structure is used for emitter application, then the absorption efficiency is high, but the structure cannot withstand high temperatures required for emitter use

Engineering Contradiction:
Improveabsorption efficiencyVSAvoidtemperature resistance
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the material parameters by selecting substances with high melting points and thermal stability (e.g., tungsten, molybdenum, silicon nitride) to maintain structural integrity at emitter operating temperatures while preserving optical absorption properties through controlled layer thicknesses and compositions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite layered structure combines materials with complementary properties: some layers provide thermal stability and structural strength, while others optimize optical absorption in the infrared range, achieving both high temperature resistance and high absorption efficiency simultaneously.

Inventive Principle:
Principle #40Composite materials

3Loss of energy

If the optical structure is optimized for detector use, then the emission/absorption performance is excellent, but the structure is not suitable for emitter use due to temperature limitations

Engineering Contradiction:
Improveemission efficiencyVSAvoiddual-use capability
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent designs a universal optical structure that functions effectively as both a detector and an emitter by using symmetric layered configurations and materials that maintain their optical and thermal properties across different operating conditions, allowing the same structure to be adapted for dual purposes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The structure achieves dual functionality by controlling material parameters such as layer thickness, composition ratios, and doping levels to optimize performance for both detection and emission modes, with the ability to adjust parameters based on the specific application requirements.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If a protecting layer is added to enhance stability at high temperature, then the reliability improves, but the device complexity increases

Engineering Contradiction:
Improvestability at high temperatureVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the protecting layer function with existing structural layers by integrating thermal barrier and oxidation protection capabilities into the emitter body structure itself, rather than adding separate protective components, thereby enhancing reliability while minimizing increases in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 structure achieves enhanced stability and reduced thermal mass, enabling efficient operation as both an emitter and detector at high temperatures, with improved manufacturing cost-effectiveness and reliability.

Implementation Method 1

a layered structure in the surface, which absorbs (and correspondingly thus emits) radiation extremely well in the wavelength range in question

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

the same optical structure can, suitably adapted, be also used as a detector, which absorbs electromagnetic radiation... in thermal infrared detectors, a surface is required that absorbs effectively infrared radiation in the desired wavelength range. Correspondingly, in infrared emitters, a surface is required that emits effectively

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

a white surface refers, in turn, to a surface, which reflects radiation extremely well in the wavelength range in question... it is, among other things, possible to reduce disturbances outside the selected wavelength range

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2893770B1Optical layered structure, manufacturing method, and use
Publication Date: 2023.04.26 VAISALA
  • EP2893770B1 patent drawingFigure 1~2
  • EP2893770B1 patent drawingFigure 3~4
  • EP2893770B1 patent drawingFigure 5~6

AI summary

The present publication describes a heat-resistant optical layered structure, a manufacturing method for a layered structure, and the use of a layered structure as a detector, emitter, and reflecting surface. The layered structure comprises a reflecting layer (2), an optical structure on top of the reflecting layer (2), and preferably shielding layers (1, 3, 5, 7) for shielding the reflecting layer (2) and the optical structure. According to the invention, the optical structure on top of the reflecting layer (2) comprises at least one partially transparent layer (6), which is optically fitted at a distance to the reflecting layer (2).