Non-contact temperature measurement systems and methods

Patent metadata

Field	Value
Publication number	US-12025504-B2
Application number	US-202117499370-A
Country	US
Kind code	B2
Filing date	Oct 12, 2021
Priority date	Oct 12, 2021
Publication date	Jul 2, 2024
Grant date	Jul 2, 2024

Abstract

Methods and systems for non-contact temperature measurement of an object on which is attached or etched a diffraction grating. The diffraction grating expands and contracts as the object expands and contracts upon there being a change in temperature of the object. Upon a light beam being received on the diffraction grating, the diffraction grating produces a pair of complementary light beams and one of the light beams is reflected back onto the diffraction grating and then onto the other light beam in a manner that causes the reflected light beam to propagate alongside and non-parallel to the other light beam. The resultant two light beams are thereafter impinged onto a camera at respective first and second impingement locations. The temperature of the object is then determined based on the separation distance between the first and second impingement locations.

First claim

What is claimed is:

1. A system for non-contact temperature measurement of an object that expands and contracts with a change in temperature of the object, the system comprising:
a light source configured to emit a light beam;
a diffraction grating including grating lines, the diffraction grating attached to or etched on the object, the diffraction grating configured to expand and contract as the object expands and contracts so that spacing between the grating lines change with a change in temperature of the object, the diffraction grating configured to receive the light beam and to produce an order pair of first and second light beams;
a mirror arranged to reflect the first light beam back onto the diffraction grating, the mirror and diffraction grating being configured to cause the reflected first light beam to propagate alongside and non-parallel to the second light beam;
a camera configured to simultaneously receive the reflected first light beam and the second light beam at respective first and second impinging locations; and
means for determining the temperature of the object based on a separation distance between the first and second impingement locations.

2. The system according to claim 1 , further comprising a plurality of mirrors disposed in an optical pathway located between the diffraction grating and the camera, the plurality of mirrors being arranged with respect to one another to cause an increase in distance traveled by the reflected first light beam and the second light beam before being received in the camera.

3. The system according to claim 1 , wherein the diffraction grating is a reflective grating.

4. The system according to claim 1 , wherein the diffraction grating is a transmission grating.

5. The system according to claim 1 , wherein the camera is a charge coupled device.

6. The system according to claim 1 , further comprising a telescope located in an optical pathway between the light source and diffraction grating that expands the light beam emitted by the light source.

7. The system according to claim 1 , wherein the light beam is a laser beam.

8. The system according to claim 1 , wherein the diffraction grating diffracts the first and second light beams in a horizontal plane.

9. The system according to claim 1 , wherein the diffraction grating diffracts the first and second light beams in a vertical plane.

10. The system according to claim 1 , further comprising an optical filter located in an optical flow path of the reflected first light beam and the second light beam, the optical filter configured to permit a particular wavelength of the reflected first light beam and the second light beam to pass onto the camera.

11. A method for non-contact temperature measurement of an object on which is attached or etched a diffraction grating, the diffraction grating configured to expand and contract as the object expands and contracts with a change in temperature of the object, the method comprising:
directing a light beam onto the diffraction grating to produce an order pair of first and second light beams;
reflecting the first light beam back onto the diffraction grating in a manner that causes the reflected first light beam to propagate alongside and non-parallel to the second light beam;
impinging the reflected first light beam and the second light beam onto a camera at respective first and second impingement locations;
determining a separation distance between the first and second impingement locations; and
determining the temperature of the object based on the determined separation distance.

12. The method according to claim 11 , further comprising reflecting the reflected first light beam and the second light beam with the use of a plurality of mirrors disposed in an optical pathway located between the diffraction grating and the camera to cause an increase in distance traveled by the reflected first light beam and the second light beam before being received in the camera.

13. The method according to claim 11 , wherein the diffraction grating is a reflective grating.

14. The method according to claim 11 , wherein the diffraction grating is a transmission grating.

15. The method according to claim 11 , wherein the camera is a charge coupled device.

16. The method according to claim 11 , further comprising expanding the light beam emitted by the light source by the use of a telescope.

17. The method according to claim 11 , wherein the light beam is a laser beam.

18. The method according to claim 11 , wherein the diffraction grating diffracts the positive order light beam and negative order light beam in a horizontal plane.

19. The method according to claim 11 , wherein the diffraction grating diffracts the positive order light beam and negative order light beam in a vertical plane.

20. The method according to claim 11 , further comprising placing an optical filter in an optical flow path of the reflected first light beam and of the second light beam, the optical filter configured to permit a particular wavelength of the reflected first light beam and of the second light beam to pass onto the camera.

Assignees

• L3Harris Technologies Inc

Inventors

• Miesak Edward
• Blenke Lawrence

Classifications

• G01B11/165

  by means of a grating deformed by the object · CPC title

• G01K5/48

  the material being a solid · CPC title

• G01K11/12

  using changes in colour, translucency or reflectance · CPC title

• G01K1/024

  for remote indication · CPC title

• G02B27/0944 Primary

  Diffractive optical elements, e.g. gratings, holograms (gratings per se G02B5/18; holograms used as optical elements per se G02B5/32) · CPC title