Apparatus and method for in-situ calibration of a photoacoustic sensor

Patent metadata

Field	Value
Publication number	US-11275059-B2
Application number	US-201916699993-A
Country	US
Kind code	B2
Filing date	Dec 2, 2019
Priority date	Sep 7, 2015
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

An apparatus for in-situ calibration of a photoacoustic sensor is provided. The apparatus includes a calibration unit that includes at least one processor configured to calculate calibration information. A light emitter of the photoacoustic sensor is configured to emit an electromagnetic spectrum and the photoacoustic sensor is configured to provide at least two measurement signals based on at least two electromagnetic spectra. The calibration unit is configured to compare the at least two measurement signals to obtain the calibration information and apply the calibration information to the photoacoustic sensor to perform the in-situ calibration.

First claim

What is claimed is:

1. An apparatus for in-situ calibration of a photoacoustic sensor, the apparatus comprising:
a calibration unit comprising at least one processor, configured to calculate calibration information, wherein a light emitter of the photoacoustic sensor is configured to emit a first electromagnetic spectrum that is sensitive to a gas and a second electromagnetic spectrum that is not sensitive to the gas, wherein the photoacoustic sensor is configured to provide at least two measurement signals based on the first and the second electromagnetic spectrum passing through the gas,
wherein the calibration unit is configured to compare the at least two measurement signals to obtain the calibration information, and
wherein the calibration unit is configured to apply the calibration information to the photoacoustic sensor to perform the in-situ calibration.

2. The apparatus according to claim 1 , wherein the calibration unit is configured to apply the calibration information to an output signal of the photoacoustic sensor to perform the in-situ calibration.

3. The apparatus according to claim 1 , wherein the calibration unit is configured to control an electric signal at the light emitter,
wherein the light emitter is configured to emit an electromagnetic spectrum based on the electric signal, and
wherein the calibration unit is further configured to adjust the electric signal at the light emitter based on the calibration information to perform the in-situ calibration.

4. The apparatus according to claim 1 , further comprising:
a processing unit, comprising as least one further processor, configured to calibrate a determination of a gas concentration in the photoacoustic sensor using the calibration information to perform the in-situ calibration,
wherein the determination of the gas concentration is based on a further measurement signal of the photoacoustic sensor.

5. The apparatus according to claim 1 , further comprising:
a processing unit, comprising as least one further processor, configured to process an output signal of the photoacoustic sensor based on the calibration information to obtain an adjusted output signal of the photoacoustic sensor.

6. The apparatus according to claim 1 , wherein:
the calibration unit is configured to calculate a current ratio of a first one of the at least two measurement signals and a second one of the at least two measurement signals,
the calibration unit is further configured to compare the current ratio to a target ratio, and
the calibration unit is configured to adjust an electric power of the light emitter such that an absolute difference of the current ratio to the target ratio is reduced.

7. The apparatus according to claim 1 , wherein the light emitter of the photoacoustic sensor is configured to alternate the emission of the first and the second electromagnetic spectrum a plurality of times and the photoacoustic sensor is configured to provide the at least two measurement signals based the alternated emission of the first and the second electromagnetic spectrum passing through the gas.

8. The apparatus according to claim 7 , wherein the emission of the first and the second electromagnetic spectrum are alternated at a frequency higher than an average change of a composition of the gas.

9. A method for in-situ calibration of a photoacoustic sensor, the method comprising:
calculating a calibration information, wherein an IR emitter of the photoacoustic sensor is configured to emit a first electromagnetic spectrum that is sensitive to a gas and a second electromagnetic spectrum that is not sensitive to the gas based on an electric signal, wherein the photoacoustic sensor is configured to provide at least two measurement signals based on the first and the second electromagnetic spectrum passing through the gas; and
comparing the at least two measurement signals to obtain calibration information; and
applying the calibration information to the photoacoustic sensor to perform the in-situ calibration.

10. The method of claim 9 , wherein applying the calibration information to the photoacoustic sensor includes applying the calibration information to an output signal of the photoacoustic sensor to perform the in-situ calibration.

11. The method of claim 9 , further comprising:
controlling an electric signal at the IR emitter;
emitting an electromagnetic spectrum from the IR emitter based on the electric signal; and
adjusting the electric signal at the IR emitter based on the calibration information to perform the in-situ calibration.

12. The method of claim 9 , further comprising:
calibrating a determination of a gas concentration in the photoacoustic sensor using the calibration information to perform the in-situ calibration,
wherein the determination of the gas concentration is based on a further measurement signal of the photoacoustic sensor.

13. The method of claim 9 , further comprising:
processing an output signal of the photoacoustic sensor based on the calibration information to obtain an adjusted output signal of the photoacoustic sensor.

14. The method of claim 9 , further comprising:
calculating a current ratio of a first one of the at least two measurement signals and a second one of the at least two measurement signals;
comparing the current ratio to a target ratio; and
adjusting an electric power of the IR emitter such that an absolute difference of the current ratio to the target ratio is reduced.

15. The method of claim 9 , wherein the light emitter of the photoacoustic sensor is configured to alternate the emission of the first and the second electromagnetic spectrum a plurality of times and the photoacoustic sensor is configured to provide the at least two measurement signals based the alternated emission of the first and the second electromagnetic spectrum passing through the gas.

16. The method of claim 15 , wherein the emission of the first and the second electromagnetic spectrum are alternated at a frequency higher than an average change of a composition of the gas.

17. An apparatus for in-situ calibration of a photoacoustic sensor, the apparatus comprising:
a calibration unit comprising at least one processor, configured to calculate calibration information, wherein a light emitter of the photoacoustic sensor is configured to emit a plurality of electromagnetic spectrum, wherein the photoacoustic sensor is configured to provide at least two measurement signals based on at least two electromagnetic spectra,
wherein the calibration unit is configured to compare the at least two measurement signals to obtain the calibration information,
wherein the calibration unit is configured to apply the calibration information to the photoacoustic sensor to perform the in-situ calibration,
wherein the calibration unit is configured to calculate a current ratio of a first one of the at least two measurement signals and a second one of the at least two measurement signals,
wherein the calibration unit is further configured to compare the current ratio to a target ratio, and
wherein the calibration unit is configured to adjust an electric power of the light emitter such that an absolute difference of the current ratio to the target ratio is reduced.

18. The apparatus according to claim 17 , wherein the at least two measurement signals are produced by an acoustic sensor element of the photoacoustic sensor based on the at least two electromagnetic spectra passing through a gas.

19. A method for in-situ calibration of a photoacoustic sensor, the method comp

Assignees

• Infineon Technologies Ag

Inventors

• Kolb Stefan
• Dehe Alfons
• Huber Jochen
• Jost Franz
• Theuss Horst
• Woellenstein Juergen

Classifications

• G01N21/3504

  for analysing gases, e.g. multi-gas analysis · CPC title

• G01N29/30 Primary

  Arrangements for calibrating or comparing, e.g. with standard objects · CPC title

• G01N29/2418

  using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics (photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046) · CPC title

• G01N2021/1704

  in gases · CPC title

• G01N2291/021

  Gases · CPC title