Target for calibrating and testing infrared devices

• US 5,324,937 A
• Filed: 01/21/1993
• Issued: 06/28/1994
• Est. Priority Date: 01/21/1993
• Status: Expired due to Fees

• Current Assignee: Hughes Aircraft Company (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Shih, I-Fu, Chen, Wallace W.
• Primary Examiner(s): Hannaher, Constantine
• Assistant Examiner(s): Glick, Edward J.
• Application Number:
  US08/010,125
• Time in Patent Office: 523 Days
• Field of Search: 250/252.1 A, 250/252.1 R, 250/330, 250/338.1, 250/493.1, 250/504 R, 374/1, 374/2, 29/458, 29/460
• US Class Current: 250/252.1
• CPC Class Codes: F41J 2/02 Active targets transmitting infrared radiation
• CPC Class Codes: G01J 5/53 Reference sources, e.g. standard lamps; Black bodies

Abstract

An improved target for testing and calibrating a detection device. The target (10) includes a metal substrate (12) with a first layer (14) of high emissivity material and a second layer (16) of low emissivity material are deposited thereon. In the specific implementation, the substrate (12) is copper, the first layer (14) is chromium-oxide and the second layer (16) is chrome. In the illustrative embodiment, an aperture (22) is drilled through the substrate (12) and the first and second layers (14, 16) thereon. An infrared emitter (20) is located at the aperture (22) to provide point source radiation. A conventional heater (26) is applied to the back surface of the target. A pattern is etched on second layer (16) on the front surface of the target using electron beam lithography. The use of a metal substrate (12) allows for the drilling of small holes more easily than in the conventional target. In addition, the metal substrate (12) provides good temperature uniformity without use of a separate metal plate due to the higher thermal conductivity of metal over glass. The elimination of the separate metal plate also simplifies target assembly and reduces target costs.

Claims

1. An improved target for testing and calibrating a detection device, comprising;

a metal substrate;

a first layer of high emissivity material formed on said metal substrate;

a second layer of low emissivity coated on said first layer; and

an aperture extending through said metal substrate, said first layer and said second layer.

2. The invention of claim 1 wherein said metal substrate is copper.

3. The invention of claim 2 wherein said first layer is chromium-oxide.

4. The invention of claim 3 wherein said second layer is chrome.

5. The invention of claim 1 wherein said metal substrate is molybdenum.

6. The invention of claim 1 wherein said first layer is chromium-oxide.

7. The invention of claim 1 wherein said second layer is chrome.

8. The invention of claim 1 wherein said aperture is aligned with a bore formed in said substrate and having a bore diameter, and said aperture has an aperture cross-sectional dimension which is smaller than said bore diameter.

9. An improved target for testing and calibrating a detection device comprising:

a metal substrate;

a first layer of high emissivity material on said metal substrate;

a second layer of low emissivity coated on said first layer;

said substrate having an aperture which extends through said first and second layers;

a source of optical energy disposed to radiate optical energy through said aperture; and

means for applying heat to said metal substrate.

10. The invention of claim 9 wherein said metal substrate is copper.

11. The invention of claim 10 wherein said first layer is chromium-oxide.

12. The invention of claim 11 wherein said second layer is chrome.

13. The invention of claim 9 wherein said source includes an optical fiber.

14. The invention of claim 13 wherein said source includes an emitter of infrared radiation.

15. The invention of claim 9 wherein said aperture is aligned with a bore formed in said substrate and having a bore diameter, and said aperture has an aperture cross-sectional dimension which is smaller than said bore diameter.

16. The invention of claim 15 wherein said source comprises an optical fiber having an end fitted into said bore.

17. An improved method of fabricating emissivity targets, including the steps of:

depositing a first layer of high emissivity material on a metal substrate;

depositing a second layer of low emissivity material on said first layer; and

forming an aperture extending through said substrate and said first and second layers.

18. The invention of claim 17 wherein said step of forming an aperture comprises drilling said aperture through said substrate and said first and second layers thereon.

19. The invention of claim 17 wherein said aperture is aligned with a bore formed in said substrate and having a bore diameter, and said aperture has an aperture cross-sectional dimension which is smaller than said bore diameter.

20. The invention of claim 19 further comprising the step of inserting an end of an optical fiber into said bore.