PHOTO-ACOUSTIC GAS SENSOR AND METHOD FOR THE PRODUCTION AND USE THEREOF

• US 20120260719A1
• Filed: 10/07/2010
• Published: 10/18/2012
• Est. Priority Date: 10/15/2009
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Schade, Wolfgang
• Granted Patent: US 9,068,926 B2
• Time in Patent Office: Days
• US Class Current: 73/24.02
• CPC Class Codes: G01N 2021/1704 in gases
• CPC Class Codes: G01N 21/1702 with opto-acoustic detection, e.g. for gases or analysing solids
• CPC Class Codes: G01N 2201/024 Modular construction

Abstract

A photo-acoustic gas sensor and methods for producing same, the gas sensor having a resonance body and a device for detecting a vibration of the resonance body, including a device for optically detecting the location of at least one partial surface of the resonance body, wherein the resonance body and the device for detecting a vibration are disposed on exactly one substrate, the resonance body is formed by at least one first recess of the substrate, and the substrate is a semiconductor material.

Claims

1-19. -19. (canceled)

20. A photo-acoustic gas sensor, comprising a resonance body and an interferometer for identifying an oscillation of the resonance body by optically detecting the location of at least one partial area of the resonance body, wherein the interferometer is arranged on exactly one substrate comprising a semiconductor material, and the resonance body is formed by at least one first cutout in the substrate.

21. The gas sensor according to claim 20, wherein the resonance body has at least two elongated elements which are arranged approximately parallel to each other and wherein each of these elements is fixed to a connecting element at a base point and projects freely at their end opposite to the base point, wherein a second cutout is formed between both elements and the first cutout is formed between the substrate and one element.

22. The gas sensor according to claim 20, wherein the interferometer comprises at least two optical waveguides which are guided parallel in a partial section, such that a crosstalk of the signals respectively guided in the optical waveguides is possible.

23. The gas sensor according to claim 20, wherein at least one device for generating light and/or a device for detecting light and/or a device for electronic signal processing and/or a device for energy supply are/is integrated on the substrate.

24. The gas sensor according to claim 23, wherein at least one first electronic component is integrated on the substrate by means of CMOS technology and/or a second electronic component is connected to the substrate by means of flip-chip bonding.

25. The gas sensor according to claim 23, wherein the device, for electronic signal processing comprises a device for the radio transmission of a data signal and/or an A/D converter and/or a signal amplifier and/or a discriminator and/or a receiving device for a data signal.

26. The gas sensor according to claim 23, wherein the device for energy supply comprises at least one photovoltaic cell or a monolithically integrated photovoltaic cell.

27. The gas sensor according to claim 23, comprising further at least one resonator which at least partly delimits a volume intended for receiving molecules to be detected.

28. The gas sensor according to claim 27, wherein the resonator is connected to the substrate by means of a bonding method and/or is monolithically integrated in the substrate.

29. The gas sensor according to claim 20, comprising further at least one contact layer being adapted to electrically connect at least two devices and/or two electronic components of such a device.

30. The gas sensor according to claim 20, wherein at least one optical waveguide is integrated using silicon-on-insulator technology on and/or in the substrate.

31. The gas sensor according to claim 20, comprising at least one first substrate, comprising the resonance body and the interferometer for identifying an oscillation of the resonance body, and at least one second substrate, on which at least one device for generating light and/or a device for detecting light and/or a device for electronic signal processing and/or a device for energy supply are/is integrated on the substrate, wherein the first substrate and the second substrate is connectable by means of electrical and/or optical contact elements.

32. The gas sensor according to claim 31, wherein the first substrate has a recess provided for receiving the second substrate.

33. The method according to claim 32, wherein energy is supplied by means of at least one solar cell to at least one device for generating light and/or at least one device for identifying the oscillation of the resonance body and/or at least one device for transmitting a signal representing the oscillation of the resonance body.

34. The method according to claim 32, implementing any of a process control in industrial installations and/or a room air monitoring and/or a breath gas monitoring and/or a determination of the calorific value of a fuel gas and/or a fire protection monitoring and/or an analysis of skin emanations of a living organism and/or quality monitoring and/or ripeness degree monitoring of foodstuffs or plants in refrigerated containers.

32-1. A method for photo-acoustically detecting molecules in the gas phase, comprising the following steps:

introducing the molecules to be detected into a volume at least partly delimited by at least one micromechanical resonator,

supplying light for exciting a photo-acoustic signal into the volume intended for receiving the molecules to be detected,

identifying an oscillation of a resonance body by optically detecting the location of at least two partial areas of the resonance body, said oszillation being generated by a photoacoustic signal being stimulated inside the micromechanical resonator,

transmitting a signal representing the oscillation of the resonance body by means of radio transmission.

35. A method for producing a gas sensor, said method comprising the following steps:

providing a substrate comprising a semiconductor material,

producing at least one device for generating light and/or a device for detecting light and/or a device for electronic signal processing and/or a device for energy supply on the substrate,

introducing at least one first cutout and/or a second cutout into the substrate.

36. The method according to claim 35, comprising further the step of

producing a resonator at least partly delimiting a volume being intended for receiving molecules to be detected.

37. The method according to claim 35, wherein at least one electronic component is provided using CMOS technology and/or at least one electronic component is connected to the substrate by means of flip-chip bonding.