METHOD AND APPARATUS FOR REMOTE DETECTION OF ALCOHOL VAPORS IN THE ATMOSPHERE

• US 20130334419A1
• Filed: 05/23/2013
• Published: 12/19/2013
• Est. Priority Date: 05/29/2012
• Status: Active Grant

• Current Assignee: Airoptic Sp. z o.o.
• Original Assignee: Airoptic Sp. z o.o.
• Inventors: KLUCZYNSKI, Pawel, LUNDQVIST, Stefan
• Granted Patent: US 9,068,885 B2
• Time in Patent Office: Days
• US Class Current: 250/339.13
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 33/4972 Determining alcohol content for vehicle safety devices B60K28/06

Abstract

A light beam generated by a light source having a wavelength corresponding to the ethanol absorption spectrum, preferably in the wavelength range of 3.28-3.52 μm or in one or more wavelength ranges 6.49-7.46 μm, 7.74-8.33 μm, 8.84-10.10 μm, 10.7-12.00 μm, is sent through a measuring space containing a sample of exhaled breath, and then the intensity of the light beam passing through the measuring space is measured. Based on the spectral analysis of the dependence of the light intensity to the alcohol concentration, the concentration of ethanol vapor is determined and the information about the level of the ethanol content is provided to a suitable display or device.

Claims

1-22. -22. (canceled)

23. A method for remote detection of alcohol vapor in the atmosphere, particularly useful for determination of the concentration of ethanol vapor in the air exhaled by humans, wherein a beam of light, preferably from a laser light source with a wavelength corresponding to the absorption spectrum of alcohol, preferably in the wavelength range of 3.28-3.52 μ

m, or in one or several wavelength ranges of 6.49-7.46 μ

m, 7.74-8.33 μ

m, 8.84-10.10 μ

m, 10.7-12.00 μ

m, is sent across a measurement space, and then the light intensity is measured after the beam has passed through said space, and then, based on spectral analysis of the dependence of the light intensity on the alcohol level, the concentration of alcohol vapor is determined.

24. The method according to claim 23, wherein the wavelength of the light source is tuned over a wavelength range covering a sharp absorption feature of ethanol at a wavelength of 3.345 μ

m or 7.174 μ

m or 8.057 μ

m or 9.377 μ

m or 11.372 μ

m and a part of and/or the whole of an absorption ‘

plateau’

, preferably located in close proximity of said sharp feature.

25. The method according to claim 24, wherein in addition the wavelength is tuned over a wavelength range covering a single absorption line or multiple absorption lines of a tracer gas, such as carbon dioxide and/or water vapor used to measure the amount of exhaled breath.

33. The method according to claim 23, wherein after the determination of the level of alcohol vapor concentration, the information is supplied to a suitable display and/or other equipment for further processing.

26. A method of remote detection of ethanol vapor concentration in the exhaled breath from persons inside the cabin of a vehicle, wherein a beam of laser light at a wavelength range corresponding to the spectrum of ethanol absorption is generated, preferably in the wavelength range around 3.345 μ

m, said wavelength range covering the whole or a part of a sharp absorption feature of ethanol at a wavelength of 3.345 μ

m, whereas said laser beam is sent through the cabin of the vehicle, and then the intensity of the light is measured after the beam is passed through the measurement space and the concentration of alcohol vapor is determined by means of spectral analysis of the dependence of the light intensity on the alcohol concentration.

27. The method according to claim 26, wherein the wavelength of the light source is tuned over a wavelength range covering a sharp absorption feature of ethanol at a wavelength of 3.345 μ

m, including a part of, or the whole of, an absorption ‘

plateau’

preferably located in proximity of the sharp absorption feature of ethanol.

28. The method according to claim 27, wherein immediately before the measurement of ethanol, a background signal, which contains the absorption signal from atmospheric gases, the characteristics of the light source including any distortion of the received optical signal, is recorded and removed from the measurement signal.

29. The method according to claim 27, wherein in addition the wavelength is tuned over a wavelength range covering a single absorption line or multiple absorption lines of a tracer gas, such as carbon dioxide and/or water vapor.

30. The method according to claim 28, wherein also a second light source with a wavelength corresponding to an absorption feature of a tracer gas such as carbon dioxide or water vapor is used, the generated light beam from the second light source is passed through the passenger compartment of the vehicle containing a sample of exhaled air, the level of carbon dioxide or water vapor in the cabin of the vehicle is determined based on the measurement of the level of light detected from the second source, and then the level of alcohol in the breath is calculated using the measured absorption level of the ethanol vapor and the measured tracer gas level in the cabin.

31. A method for detecting the presence of ethanol vapor in the air exhaled by humans wherein a modulated beam of light is generated at a wavelength corresponding to an absorption feature of ethanol within the wavelength range of 3.28-3.52 μ

m, or within one or more of the wavelength ranges of 6.49-7.46 μ

m, 7.74-8.33 μ

m, 8.84-10.10 μ

m, 10.7-12.00 μ

m, and the said beam of light is passed through a space containing the exhaled breath, the light passing through this space is measured, preferably using the Wavelength Modulation Spectroscopy (WMS) method, and the level of ethanol vapor in the exhaled air is determined based on the level of light detected after the said beam passed through the said space.

32. The method according to claim 31, wherein a source of light of a wavelength corresponding to the absorption spectrum of a tracer gas, such as carbon dioxide or water vapor, present in the exhaled air, is generated and sent through a defined space, containing the sample of exhaled breath, the intensity of said light passing through this space is measured and the level of carbon dioxide and/or water vapor in the breath sample is determined based on the level of detected light, and then the level of ethanol vapor in the exhaled breath is calculated by means of the measured absorption level of ethanol vapor and the tracer gas concentration level in said measuring space.

34. A device for remote detection of ethanol vapor concentration in exhaled air, comprising a light source, preferably a laser, and a detector for detecting the intensity of the light from said light source emitting at a wavelength corresponding to the spectrum of ethanol absorption, wherein said device is equipped with a synchronizing-calculating module for determination of the concentration of ethanol by means of spectral analysis which is connected to the detector for detecting the light intensity whereas the said light source emits a beam of light in the wavelength range of 3.28-3.52 μ

m, or within one or more of the wavelength ranges of 6.49-7.46 μ

m, 7.74-8.33 μ

m, 8.84-10.10 μ

m, 10.7-12.00 μ

m.

35. The device according to claim 34, wherein the light source is a tunable, single-mode semiconductor laser GaInAsSb/AlGaInAsSb

36. The device according to claim 34, wherein the light source is a tunable quantum cascade laser, preferably an Interband Cascade Laser (ICL).

37. The device according to claim 34, wherein the light source is a tunable vertical-cavity surface-emitting laser (VCSEL).

38. The device according to claim 34, wherein the light beam is a created by difference frequency generation (DFG), which generates light by means of differential mixing of light waves from two lasers.

39. The device according to claim 34, wherein the light source is configured to emit a light beam with a wavelength of 3.345 μ

m or 7.174 μ

m or 8.057 μ

m or 9.377 μ

m or 11.372 μ

m, with the possibility of wavelength tuning through a sharp absorption feature of ethanol vapor, which occur at wavelengths of 3.345 μ

m or 7.174 μ

m or 8.057 μ

m or 9.377 μ

m or 11.372 μ

m.

40. The device according to claim 34, wherein the light source is additionally tuned over a wavelength range covering a single absorption line or multiple absorption lines of a trace gas, such as carbon dioxide and/or water vapor, in order to determine the absolute concentration of ethanol in the exhaled air.

41. The device according to claim 34, wherein it is equipped with an additional source of laser light at a wavelength corresponding to an absorption line of tracer gas contained in the exhaled breath, such as carbon dioxide or water vapor, in order to determine the absolute concentration of ethanol in the exhaled air.

42. The device according to claim 34, wherein it is configured to detect the presence of alcohol vapor in the passenger compartment of a vehicle, using a beam of light with a wavelength of 3.345 μ

m.

43. The device according to claim 34, wherein the transmitter and receiver are located on opposite sides of the measuring space.

44. The device according to claim 34, wherein it is equipped with a retro-reflector to redirect the beam to a receiver, where the transmitter and receiver are on the same side of the measuring space.