Portable IR thermometer having thermal imaging capability

• US 8,136,984 B1
• Filed: 04/20/2009
• Issued: 03/20/2012
• Est. Priority Date: 04/20/2009
• Status: Active Grant

• Current Assignee: Fluke Corporation (Fortive Corp.)
• Original Assignee: Fluke Corporation (Fortive Corp.)
• Inventors: Heinke, Thomas
• Primary Examiner(s): Verbitsky, Gail
• Application Number:
  US12/411,908
• Time in Patent Office: 1,065 Days
• Field of Search: 374/120, 374/121, 374/137, 374/179, 374/208, 374/124, 374/129, 374/1, 374/170, 374/2, 374/29, 374110-112, 374/115, 374166-167, 374/4, 374/5, 374/100, 374/178, 250/338.1, 250/339.02, 250/339.11, 250/338.03, 250/339.04, 136/200, 136/225, 136/213, 136/224
• US Class Current: 374/121
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/025 Interfacing a pyrometer to an external device or network; User interface
• CPC Class Codes: G01J 5/0265 Handheld, portable ear thermometers G01J5/049
• CPC Class Codes: G01J 5/14 Electrical features thereof

Abstract

A portable noncontact thermometer comprising a housing defining an aperture for ingress of incident thermal energy in a field of view. A graphical display is fixed with respect to the housing. The thermometer further comprises a thermopile array including a plurality of thermopile elements positioned inside the housing so as to be impinged by the incident thermal energy. The thermometer further includes processing circuitry in electrical communication with the thermopile array. The processing circuitry is operative to produce on the graphical display a thermal image of the field of view. The processing circuitry is further operative to determine a temperature of a target location within the field of view based on electrical signals derived from a subset of the thermopile elements. The subset of thermopile elements may be a single thermopile element located approximately at a center of the thermopile array.

Claims

1. A portable noncontact thermometer comprising:

a housing defining an aperture for ingress of incident thermal energy in a field of view;

a graphical display fixed with respect to said housing;

a thermopile array including a plurality of thermopile elements, said thermopile array being positioned inside said housing so as to be impinged by said incident thermal energy;

processing circuitry in electrical communication with said thermopile array, said processing circuitry being operative to produce on said graphical display a thermal image of said field of view;

said processing circuitry being further operative to determine a temperature of a target location within said field of view based on electrical signals derived from a subset of said thermopile elements; and

wherein said subset of said thermopile elements are connected to said processing circuitry without passing through a multiplexer in a common package with said thermopile array whereas outputs of said thermopile elements which are not among said subset of thermopile elements are multiplexed before amplification.

2. A portable noncontact thermometer as set forth in claim 1, wherein said subset of said thermopile elements is a single thermopile element.

3. A portable noncontact thermometer as set forth in claim 2, wherein said single thermopile element is located approximately at a center of said thermopile array.

5. A portable noncontact thermometer as set forth in claim 3, wherein said single thermopile element is directly connected to an amplifier without multiplexing.

6. A portable noncontact thermometer as set forth in claim 1, wherein said thermopile elements other than said subset are connected to said processing circuitry by passing through a multiplexer in said common package.

7. A portable noncontact thermometer as set forth in claim 1, wherein said thermopile elements within said subset are each connected to a respective amplifier.

8. A portable noncontact thermometer as set forth in claim 1, wherein said thermopile array is a 4×

4 array.

9. A portable noncontact thermometer as set forth in claim 1, wherein said thermopile array is a 10×

10 array.

10. A portable noncontact thermometer as set forth in claim 1, wherein said thermopile array is a 16×

16 array.

11. A portable noncontact thermometer as set forth in claim 1, wherein said thermopile array is a 32×

32 array.

12. A portable noncontact thermometer as set forth in claim 1, wherein said processing circuitry is further operative to show said temperature of said target location on said graphical display.

13. A portable noncontact thermometer as set forth in claim 12, wherein said temperature of said target location is superimposed on said thermal image.

14. A portable noncontact thermometer as set forth in claim 1, wherein said target location is indicated by crosshairs superimposed on said thermal image.

4. A portable noncontact thermometer comprising:

a housing defining an aperture for ingress of incident thermal energy in a field of view;

a graphical display fixed with respect to said housing;

a thermopile array including a plurality of thermopile elements, said thermopile array being positioned inside said housing so as to be impinged by said incident thermal energy;

processing circuitry in electrical communication with said thermopile array, said processing circuitry being operative to produce on said graphical display a thermal image of said field of view;

said processing circuitry being further operative to determine a temperature of a target location within said field of view based on electrical signals derived from a subset of said thermopile elements; and

wherein said subset of said thermopile elements is a single thermopile element that is located approximately at a center of said thermopile array and occupies greater surface area on said array than other of said thermopile elements.

15. A noncontact thermometer comprising:

a housing defining an aperture for ingress of incident thermal energy in a field of view;

a graphical display;

a thermopile detector including a thermopile array having a plurality of thermopile elements arranged in rows and columns;

said thermopile detector further having at least one multiplexer in a common package with said array through which a subset of said thermopile elements are connected;

processing circuitry in electrical communication with said thermopile detector so as to receive electrical signals from said thermopile elements other than said subset through said at least one multiplexer and from said subset without multiplexing;

said processing circuitry being operative to produce on said graphical display a thermal image of said field of view; and

said processing circuitry being further operative to determine a temperature of a target location within said field of view based on electrical signals from said subset of said thermopile elements.

16. A noncontact thermometer as set forth in claim 15, wherein said subset of said thermopile elements is a single thermopile element.

17. A noncontact thermometer as set forth in claim 16, wherein said single thermopile element is located approximately at a center of said thermopile array.

18. A noncontact thermometer as set forth in claim 17, wherein said single thermopile element occupies greater surface area on said array than other of said thermopile elements.

19. A noncontact thermometer as set forth in claim 15, wherein said subset of said thermopile elements are each connected to a respective amplifier.

20. A noncontact thermometer as set forth in claim 15, wherein said temperature of said target location is superimposed on said thermal image.

21. A noncontact thermometer as set forth in claim 15, wherein said target location is indicated by crosshairs superimposed on said thermal image.

22. A method of detecting temperature of a target location within a field of view, said method comprising steps of:

(a) providing a thermopile array having a plurality of thermopile elements;

(b) amplifying electrical signals produced at a subset of said thermopile elements using a narrower bandwidth amplifier to yield amplified non-multiplexed signals;

(c) multiplexing electrical signals produced at said thermopile elements other than said subset to yield multiplexed signals;

(d) amplifying said multiplexed signals using a wider bandwidth amplifier to yield amplified multiplexed signals;

(e) processing said amplified multiplexed signals and said amplified non-multiplexed signals to produce a thermal image of said field of yield; and

(f) processing said amplified non-multiplexed signals to determine temperature of said target location.

23. A method as set forth in claim 22, wherein said subset of said thermopile elements is a single thermopile element.

24. A method as set forth in claim 23, wherein said single thermopile element is located approximately at a center of said thermopile array.

25. A method as set forth in claim 22, wherein said electrical signals are multiplexed in step (c) using at least one multiplexer located in a common package with said thermopile array.

26. A method as set forth in claim 22, wherein said temperature of said target location is superimposed on said thermal image.

27. A thermopile detector configured as a discrete electronic package, said detector comprising:

a thermopile array having a plurality of thermopile elements;

at least one multiplexer located in said package;

a subset of said thermopile elements being connected to respective output terminals of said package without multiplexing; and

said thermopile elements other than said subset being connected to an output terminal of said package shared with at least one other of said thermopile elements other than said subset via one of said at least one multiplexer.