THERMAL ISOLATION DEVICE FOR INFRARED SURVEILLANCE CAMERA

• US 20130070102A1
• Filed: 09/18/2012
• Published: 03/21/2013
• Est. Priority Date: 09/20/2011
• Status: Active Grant

• Current Assignee: DRS Network & Imaging Systems, LLC (Leonardo S.p.A.)
• Original Assignee: DRS RSTA Incorporated (Leonardo S.p.A.)
• Inventors: Gustafson, Eric J., Francisco, Glen, Ward, Adam J.
• Granted Patent: US 9,386,239 B2
• Time in Patent Office: Days
• US Class Current: 348/164
• CPC Class Codes: G01J 2005/063 Heating; Thermostating
• CPC Class Codes: G01J 5/05 Means for preventing contamination of the components of the optical system; Means for preventing obstruction of the radiation path
• CPC Class Codes: H04N 23/23 from thermal infrared radiation
• CPC Class Codes: H04N 23/50 Constructional details
• CPC Class Codes: H04N 5/33 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

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.

Claims

1. A thermal imaging system comprising:

a 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 heating element coupled to 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.

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 isolator comprises a plastic material.

6. The thermal imaging system of claim 5 wherein the plastic material comprises a polycarbonate resin thermoplastic.

7. The thermal imaging system of claim 1 wherein the heating element is joined to a circumference of the mounting structure.

8. 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.

9. 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 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 heating element thermally coupled to the mounting structure;

an infrared imager mounted to the mounting structure; and

a front window mounted to the mounting structure.

10. The thermal camera of claim 9 wherein the thermal camera complies with the 802.3af PoE standard.

11. The thermal camera of claim 9 wherein the housing conforms to IP66.

12. The thermal camera of claim 9 wherein the thermal dam comprises a plastic material.

13. The thermal camera of claim 9 wherein the mounting structure comprises aluminum.

14. The thermal camera of claim 9 wherein the infrared imager comprises a focal plane array.

15. The thermal camera of claim 9 wherein the front window comprises an optical element.

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

17. The thermal camera of claim 15 wherein the mounting structure surrounds the optical element circumferentially.

18. 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 mounting structure;

a thermal isolator spatially separating the mounting structure from the housing;

a heating element bonded to 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 PoE standard;

determining that an ambient temperature is less than or equal to a threshold temperature;

heating the heating element; and

conducting heat from the heating element to the front window.

19. The method of claim 18 wherein the threshold temperature ranges from about −

40°

C. to about +65°

C.

20. The method of claim 18 wherein the thermal isolator is characterized by an outside diameter greater than an outside diameter of the mounting structure.