Thermal isolation device for infrared surveillance camera

Patent metadata

Field	Value
Publication number	US-9386239-B2
Application number	US-201213622304-A
Country	US
Kind code	B2
Filing date	Sep 18, 2012
Priority date	Sep 20, 2011
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

A thermal imaging system includes a mounting structure characterized by a first thermal conductivity and a focal plane array mounted to the mounting structure. The thermal imaging system also includes an optical system coupled to the mounting structure and a heating element coupled to the mounting structure. The thermal imaging system further includes a thermal isolator coupled to the mounting structure and characterized by a second thermal conductivity lower than the first thermal conductivity.

First claim

What is claimed is:

1. A thermal imaging system comprising:
a substantially circular mounting structure characterized by a first thermal conductivity;
a focal plane array mounted to the mounting structure;
an optical system coupled to the mounting structure;
a flexible electrical heating element that is thermally coupled to and wraps around a circumference of the mounting structure; and
a thermal isolator coupled to the mounting structure and characterized by a second thermal conductivity lower than the first thermal conductivity.

2. The thermal imaging system of claim 1 wherein the mounting structure comprises a metallic material and the thermal isolator comprises a plastic material.

3. The thermal imaging system of claim 2 wherein the metallic material comprises an aluminum material.

4. The thermal imaging system of claim 1 wherein the optical system comprises a germanium lens.

5. The thermal imaging system of claim 1 wherein the thermal imaging system complies with the 802.3af Power over Ethernet (PoE) standard.

6. The thermal imaging system of claim 2 wherein the plastic material comprises a polycarbonate resin thermoplastic.

7. The thermal imaging system of claim 1 wherein an outside diameter of the thermal isolator is greater than an outside diameter of the mounting structure.

8. A thermal camera including:
a housing;
a multi-element front cover comprising:
a thermal dam joined to the housing and having a first thermal conductivity; and
a substantially circular mounting structure joined to the thermal dam, spatially separated from the housing, and characterized by a second thermal conductivity greater than the first thermal conductivity; and
a flexible electrical heating element thermally coupled to and wrapped around a circumference of the mounting structure;

an infrared imager mounted to the mounting structure; and
a front window mounted to the mounting structure.

9. The thermal camera of claim 8 wherein the thermal camera complies with the 802.3af Power over Ethernet (PoE) standard.

10. The thermal camera of claim 8 wherein the housing conforms to Ingress Protection Code 66 (IP66).

11. The thermal camera of claim 8 wherein the thermal dam comprises a plastic material.

12. The thermal camera of claim 8 wherein the mounting structure comprises aluminum.

13. The thermal camera of claim 8 wherein the infrared imager comprises a focal plane array.

14. The thermal camera of claim 8 wherein the front window comprises an optical element.

15. The thermal camera of claim 14 wherein the optical element comprises a germanium lens.

16. The thermal camera of claim 14 wherein the mounting structure surrounds the optical element circumferentially.

17. A method of operating a thermal imaging system, the method comprising:
providing a thermal camera disposed in a housing, wherein the thermal camera comprises:
a substantially circular mounting structure operable to support a focal plane array;
a thermal isolator spatially separating the mounting structure from the housing;
an electrical heating element thermally coupled to and wrapped around a circumference of the mounting structure; and
a front window coupled to the mounting structure;

providing power to the thermal imaging system in compliance with the 802.3af Power over Ethernet (PoE) standard;
determining that an ambient temperature is less than or equal to a threshold temperature;
heating the electrical heating element; and
conducting heat from the electrical heating element to the focal plane array and the front window.

18. The method of claim 17 wherein the threshold temperature ranges from −40° C. to +65° C.

19. The method of claim 17 wherein the thermal isolator is characterized by an outside diameter greater than an outside diameter of the mounting structure.

20. The method of claim 17 wherein the electrical heating element is flexible.

Assignees

• Drs Rsta Inc
• Drs Network & Imaging Systems Llc

Inventors

• Gustafson Eric J
• Francisco Glen
• Ward Adam J

Classifications

• G01J5/05 Primary

  Means for preventing contamination of the components of the optical system; Means for preventing obstruction of the radiation path · CPC title

• H04N23/50 Primary

  Constructional details · CPC title

• H04N23/52 Primary

  Elements optimising image sensor operation, e.g. for electromagnetic interference [EMI] protection or temperature control by heat transfer or cooling elements · CPC title

• H04N23/23

  from thermal infrared radiation · CPC title

• H04N5/33 Primary

  Transforming infrared radiation (cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20) · CPC title