AN OPTICAL MICRO-SPECTROMETER

• US 20060262303A1
• Filed: 05/16/2006
• Published: 11/23/2006
• Est. Priority Date: 05/17/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Johnson, Klein, Marta, Teresa, Detry, James, Bonne, Ulrich
• Granted Patent: US 7,502,109 B2
• Time in Patent Office: Days
• US Class Current: 356/328
• CPC Class Codes: G01F 1/6845 Micromachined devices
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/20 Rowland circle spectrometers
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 2021/058 Flat flow cell
• CPC Class Codes: G01N 2021/651 Cuvettes therefore
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons
• CPC Class Codes: G01N 27/02 by investigating impedance

Abstract

An optical spectrometer having a multi-wafer structure. The structure may be fabricated with MEMS technology. The spectrometer may be integrated with a fluid analyzer. A reflective grating such as a diffraction or holographic grating situated on the circumference of a Rowland circle along with a point of light emission and a detector may be a configuration of the spectrometer. Some configurations may use an external light source where the light may be optically conveyed to the point of emission on the circle. There may be a Raman configuration where an interaction of light with a sample or an interactive film of a channel in a fluid analyzer is the point of light emission for the spectrometer. In some configurations of the spectrometer, the grating and/or the film may be reflective or transmissive.

Claims

1. An optical spectrometer comprising:

a first wafer;

a second wafer having a first channel and second channel situated on the first wafer;

a light source situated at a first end of the first channel;

a reflector situated at a second end of the first channel and a first end of the second channel; and

a detector array situated at a second end of the second channel; and

wherein the light source, reflector and detector array are situated about a circumference of a circle in a plane.

2. The spectrometer of claim 1, wherein the reflector is a concave diffraction grating, a holographic concave reflective grating, or a focusing transmission grating.

3. The spectrometer of claim 1, wherein the circle is a Rowland circle.

4. The spectrometer of claim 1, wherein the light source is a micro discharge device, or a bright surface reflection from a laser focused onto a surface.

5. The spectrometer of claim 1, wherein:

the first channel and the second channel are connected to each other; and

a fluid flow channel has an inlet situated proximate to the light source, a path through the first channel and the second channel, and an outlet situated proximate to the detector array.

6. The spectrometer of claim 1, wherein the detector array is a photo-detector array.

7. The spectrometer of claim 1, wherein the first and second wafers and the first and second channels may be fabricated with MEMS technology.

8. The spectrometer of claim 2, wherein the grating comprises a set of grating grooves or a holographic grating having dimensions compatible with a spectrum or spectrums to be observed within the spectrometer.

9. A spectrometer comprising:

a first wafer;

a detector situated on the first wafer;

a second wafer situated on the first wafer, having a first opening about the detector, and having a light source;

a third wafer, situated on the second wafer, having a second opening approximately aligned with the first opening, and having a channel intersecting the first and second openings; and

a fourth wafer situated on the third wafer, and having a reflector-grating situated proximate to the second opening.

10. The spectrometer of claim 9, wherein a light path is available from the light source to the reflector-grating, and from the reflector-grating to the detector.

11. The spectrometer of claim 9, wherein:

the light source is a micro discharge device; and

the detector is a photo-detector.

12. The spectrometer of claim 9, wherein the light source, the reflector-grating and the detector are situated proximate to a circumference of a circle.

13. The spectrometer of claim 9, wherein the light source is an end of an optical fiber having another end coupled to a source of light.

14. A spectrometer comprising:

an enclosure;

a window at a first position of the enclosure;

a reflector-grating at a second position of the enclosure;

a detector at a third position of the enclosure; and

a source of light situated outside of the enclosure proximate to the window; and

wherein;

a light path may go from the source of light to the reflector-grating, and from the reflector-grating to the detector;

the source of light, the reflector-grating and the detector are situated proximate to a circumference of a circle.

15. The spectrometer of claim 14, wherein the circle is a Rowland circle.

16. The spectrometer of claim 14, wherein the source of light is for providing Raman scattering from a fluid adsorbed on a film-surface illuminated by the source of light.

17. The spectrometer of claim 14, wherein the source of light comprises a VCSEL for outputting light to impinge a sample fluid and result in Raman scattered light to follow the light path to the detector.

18. A spectrometer comprising:

a light source;

a film situated on a support;

a grating situated proximate to the film;

a detector; and

a filter situated between the grating and the detector; and

wherein;

a light path goes from the light source to the film, from the film to the grating, from the grating through the filter to the detector; and

the film emits Raman light upon impingement of light from the light source.

19. The spectrometer of claim 18, wherein the light source is a VCSEL.

20. A spectrometer comprising:

a light source;

a film situated on a support;

a filter situated between the light source and the film;

a grating situated proximate to the filter; and

a detector proximate to the grating; and

wherein;

a light path is from the light source to the film, from the film to the filter, from the filter to the grating, and from the grating to the detector; and

Raman light may be emitted from the film upon receipt of light from the light source.

21. The spectrometer of claim 20, wherein the light source is a VCSEL.