Modulatable Infrared Emitter with Segmented Micro-Heating Element

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Solution Overview

Problem

Existing modulatable infrared emitters face limitations in achieving high-frequency and broad-spectrum modulation with compact, robust, and cost-effective designs, particularly for applications like photoacoustic spectroscopy, due to thermal time constants and complex structures in prior art.

Innovation Solution

A modulatable infrared emitter comprising a structured micro-heating element and a diaphragm structure that can move relative to each other in parallel planes, allowing for quick and simple modulation of infrared radiation intensity, utilizing MEMS actuators to achieve high-frequency modulation beyond 100 Hz, and a control device for regulating the actuator for relative movement between defined positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If direct modulation by varying the current supply is used, then the emitter can be modulated, but the modulation frequency is limited due to thermal time constants and the component's lifespan is reduced

Engineering Contradiction:
Improvemodulation frequencyVSAvoidcomponent lifespan
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The heating element is segmented into multiple independent heating zones that can be individually controlled. This allows selective activation of only the necessary heating regions, reducing overall thermal mass and enabling faster modulation frequencies without compromising the lifespan of the entire component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control of the heating element by varying the current supply to different segments in real-time based on modulation requirements. This dynamic segmentation allows the system to achieve high modulation frequencies by activating/deactivating specific zones rather than modulating the entire element, thereby extending component lifespan.

Inventive Principle:
Principle #15Dynamics

2Speed

If external modulation using rotating chopper wheels is used, then faster modulation is achieved, but the setup becomes complex and not compact or robust

Engineering Contradiction:
Improvemodulation frequencyVSAvoidsetup complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent extracts the modulation function from external mechanical components (chopper wheels) and integrates it directly into the heating element itself through electronic control of segmented zones. This eliminates the need for separate modulation mechanisms, reducing setup complexity while maintaining high modulation frequencies and improving compactness and robustness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The modulation capability is merged with the heating element by implementing segmented control directly in the thermal source. This combination eliminates the need for separate modulation components like rotating choppers, thereby simplifying the overall setup while achieving the desired modulation speeds in a compact and robust configuration.

Inventive Principle:
Principle #5Merging (Combining)

3Speed

If narrowband laser sources are used, then high radiation intensities and high-frequency modulation are achieved, but only molecules matching the absorption spectrum can be detected and the cost is high

Engineering Contradiction:
Improvemodulation frequencyVSAvoiddetection range
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal infrared emitter that can detect multiple types of molecules by controlling different heating zones to emit at different wavelengths. The segmented heating element allows selective excitation of various molecular absorption bands, providing multi-functionality that replaces the need for multiple specialized lasers while maintaining high modulation frequencies and reducing costs.

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

4Adaptability or versatility

If thermal broadband emitters are used, then a broad spectrum and low cost are achieved, but the modulation frequency is limited and the setup is not compact or robust

Engineering Contradiction:
Improvespectrum breadthVSAvoidmodulation frequency
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The broadband thermal emitter is segmented into multiple independently controllable zones, each capable of being modulated at high frequencies. This segmentation allows the system to maintain the broad spectrum characteristic of thermal emitters while achieving high modulation frequencies by selectively activating and modulating individual zones, thereby resolving the contradiction between spectrum breadth and modulation speed.

Inventive Principle:
Principle #1Segmentation

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 enables high-frequency modulation of infrared radiation with a broad spectrum, achieving a high extinction ratio and improved signal-to-noise ratios, suitable for photoacoustic spectroscopy and other applications, while maintaining a compact and durable structure.

Implementation Method 1

the micro-heating element has heatable and non-heatable areas in a first plane

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

heating the heatable areas of the structured micro-heating element to emit infrared radiation

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

the aperture structure and the structured micro-heating element can be moved relative to each other in parallel planes by means of the actuator in order to modulate the intensity of the emitted infrared radiation

Methodology Applied
Scientific EffectMEMS actuation: Microelectromechanical Systems

Data Source

PatentEP3850317B1Modulation of a moving ir emitter by means of a shutter structure
Publication Date: 2024.03.20 HAHN SCHICKARD GESELLSCHAFT FUR ANGEWANDTE FORSCHUNG EV
  • EP3850317B1 patent drawingFigure 1~2
  • EP3850317B1 patent drawingFigure 3~4
  • EP3850317B1 patent drawingFigure 5~6

AI summary

The invention relates to an infrared emitter which can be modulated, comprising a diaphragm structure, a structured micro-heating element, and an actuator, wherein the diaphragm structure and the structured micro-heating element can be moved relative to each other on parallel planes using the actuator in order to modulate the intensity of the emitted infrared radiation. The invention additionally relates to methods for producing the infrared emitter, to a method for a modulated emission of infrared radiation using the infrared emitter, and to preferred applications of the infrared emitter. The invention also preferably relates to a system comprising the infrared emitter and to a controller for regulating the actuator.