Nanoparticle Wavelength Conversion for Compact PAS Gas Sensing

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Solution Overview

Problem

Existing photo-acoustic spectroscopy (PAS) setups struggle to accurately detect multiple gasses, particularly those insensitive to infrared radiation, in space-constrained and cost-effective applications due to limitations in tunable optical filters, which compromise transmissivity, selectivity, and physical form factors.

Innovation Solution

A light emitting structure for PAS devices that utilizes a conversion structure with nanoparticles to convert input light to an output wavelength tailored to target gas absorption, eliminating the need for tunable optical filters, and includes a spectral filter for selective excitation, using LEDs and polymer-embedded nanoparticles for efficient and precise gas detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If tunable optical filters are used for multi-gas detection, then selectivity is improved, but transmissivity and device compactness deteriorate

Engineering Contradiction:
Improvegas detection selectivityVSAvoiddevice form factor
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent replaces mechanical tunable optical filters with semiconductor light emitting diodes (LEDs) that directly emit at specific wavelengths. This substitution eliminates the need for bulky mechanical filter systems while maintaining wavelength selectivity, thereby resolving the contradiction between detection selectivity and device compactness.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the approach from filtering broad spectrum light to emitting narrowband light at specific wavelengths using LEDs. By changing the light source parameter from broadband (filter-based) to narrowband (emission-based), the system achieves both high selectivity and compact form factor, resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If tunable optical filters are used for multi-gas detection, then gas detection accuracy is improved, but power consumption increases

Engineering Contradiction:
Improvegas detection accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent substitutes power-consuming tunable filter mechanisms with low-power semiconductor LEDs. The LEDs directly emit at the required wavelengths without needing mechanical adjustment or broad spectrum filtering, significantly reducing power consumption while maintaining detection accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs standard semiconductor LED technology, which is cost-effective and energy-efficient compared to specialized tunable filter systems. This approach uses readily available, low-power components to achieve the same functional outcome, resolving the contradiction between accuracy and power consumption.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If tunable optical filters are used for multi-gas detection, then multi-gas detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvemulti-gas detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses multiple LED emitters, each capable of emitting at a specific wavelength corresponding to different gas absorption bands. This multi-LED configuration provides universal multi-gas detection capability without requiring complex tunable filter mechanisms, thereby reducing system complexity while maintaining versatility.

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

Solution Approach 2:

The patent segments the multi-gas detection function into multiple independent LED emitters, each responsible for a specific wavelength/gas target. This segmentation simplifies the overall system architecture compared to a single complex tunable filter, as each LED can be independently controlled and optimized for its specific function.

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

Enables accurate, cost-effective, and space-efficient multi-gas detection in noisy environments by optimizing power consumption, stability, and reducing mechanical complexity, suitable for mobile and handheld devices.

Implementation Method 1

The conversion structure comprises an output conversion layer that comprises a plurality of nanoparticles. The nanoparticles are configured for absorbing light of the input wavelength, and that is further configured for emitting light of an output wavelength

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

Photo-acoustic spectroscopy (PAS) is the measurement of the effect of absorbed electromagnetic energy, particularly of light, on matter by means of acoustic detection. The emitted radiation excites a mixture of gasses in a detection chamber. The excitation exerts pressure in an audible range that is to be detected by a detector

Methodology Applied
Scientific EffectPhoto-acoustic effect: Photoacoustic Effect

Data Source

PatentEP3859307B1Light emitting structure, photo-acoustic spectroscopy sensing device, method for operating a photo-acoustic spectroscopy sensing device and apparatus for obtaining an information about a target gas
Publication Date: 2026.04.22 INFINEON TECHNOLOGIES AG
  • EP3859307B1 patent drawingFigure 1
  • EP3859307B1 patent drawingFigure 2
  • EP3859307B1 patent drawingFigure 3

AI summary

A light emitting structure for a photo-acoustic spectroscopy sensing device for sensing a target gas comprises a light source configured for emitting light of an input wavelength. The light emitting structure further comprises a conversion structure that is configured for absorbing light of the input wavelength, and that is further configured for emitting light of an output wavelength. The output wavelength of the conversion structure is adapted to an absorption wavelength of the target gas. The conversion structure comprises an output conversion layer that comprises a plurality of nanoparticles. The nanoparticles of the output conversion layer are configured for emitting light of the output wavelength.