EMISSIVITY ENHANCED MID IR SOURCE

• US 20110068271A1
• Filed: 09/18/2009
• Published: 03/24/2011
• Est. Priority Date: 09/18/2009
• Status: Active Grant

• Current Assignee: Thermo Electron Scientific Instruments LLC (Thermo Fisher Scientific Incorporated)
• Original Assignee: Thermo Electron Scientific Instruments LLC (Thermo Fisher Scientific Incorporated)
• Inventors: Coffin, John Magie, IVERSON, John R.
• Granted Patent: US 8,975,604 B2
• Time in Patent Office: Days
• US Class Current: 250/338.4
• CPC Class Codes: G01J 3/108 for measurement in the infrared range

Abstract

An infrared (IR) source apparatus that includes a desired infrared source element coupled to an insulating housing so to minimize overall source inefficiency at desired optical bandwidths is introduced. The insulation itself is machined or configured in a way so that the infrared source element is in contact with a designed cavity in the insulation so that the IR source image becomes the average of the insulation material and the infrared element. Such an arrangement of the present invention increases the emissivity of the IR source below about 1500 wave numbers, more often, below about 1100 wave numbers, and even more particularly, at about 1079 wave numbers. Accordingly, the combined emissivity of the infrared source and the insulation substantially enhances spectral emission and eliminates or reduces spectral artifacts from the formation of oxides on the infrared source surfaces.

Claims

1. An infrared source, comprising:

an infrared element which provides infrared radiation at desired wavelengths when heated by an excitation means to a predetermined temperature range;

an insulator coupled with said infrared element so as to reach a collaborative temperature range provided by the generated heat from said infrared element, wherein said insulator at said collaborative temperature range provides for one or more desired infrared emission spectral bands that co-add with the output emission of said infrared element so as to eliminate spectral deficiencies resulting from said infrared element reaching said collaborative temperature range; and

wherein one or more walls of said insulator are configured as a conical interior that converges to an to an opening that defines an optical aperture of said source so as to enhance emission of the co-added said insulator and said infrared element optical spectral output and additionally match a field of view of a coupled spectrometer imaging element.

2. The infrared source of claim 1, wherein said co-added one or more desired infrared emission spectral bands provided by said heated insulator comprise optical radiation of less than about 1500 wavenumbers.

3. The infrared source of claim 1, wherein said co-added one or more desired infrared emission spectral bands provided by said heated insulator comprise optical radiation of at about 1079 wavenumbers.

4. The infrared source of claim 1, wherein said coupled insulator is in contact with said infrared element, and wherein said insulator heats up to a desired temperature range with said infrared source that increases the co-added emissivity by up to about 50%.

5. The infrared source of claim 1, wherein said coupled insulator is adjacent to said insulator, and wherein said insulator heats up to a desired temperature range with said infrared element so as to increase the emissivity by up to about 50%.

6. The infrared source of claim 1, wherein said infrared element comprises silicon nitride.

7. The infrared source of claim 1, wherein said infrared element comprises silicon carbide.

8. The infrared source of claim 1, wherein said insulator comprises a porous ceramic material configured to withstand the operating temperatures.

9. The infrared source of claim 7, wherein said insulator comprises at least one insulator selected from:

an aluminum oxide or a zirconium insulator.

10. The infrared source of claim 1, wherein said predetermined temperature range comprises a range from about 700 degrees C. up to about 1400 degrees C.

11. The infrared source of claim 1, wherein collaborative temperature range comprises a range from about 700 degrees C. up to about 1400 degrees C.

12. The infrared source of claim 1, wherein said excitation means comprises at least one excitation means selected from:

an electrical source and an optical source.

13. The infrared source of claim 1, wherein said optical source includes a laser diode.

14. The infrared source of claim 1, wherein said walls of said insulator are configured as conical interior surfaces converging to a circular opening which defines said optical aperture of said source.

15. The infrared source of claim 14, wherein said coupled spectrometer imaging element comprises f-numbers from about f/4 to about f/1 so as to have said field of view optimized with said optical aperture.