Electromagnetic radiation attenuating and scattering member with improved thermal stability

• US 6,912,049 B2
• Filed: 12/18/2002
• Issued: 06/28/2005
• Est. Priority Date: 12/19/2001
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: NIR Diagnostics Incorporated
• Inventors: Pawluczyk, Romuald, Cadell, Theodore, Bednarz, Bronislaw, Kaushal, Ashwani
• Primary Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US10/321,510
• Publication Number:
  US 20040008343A1
• Time in Patent Office: 923 Days
• Field of Search: 356/243.1, 356/243.8, 356300-302, 356304-307, 356/319, 356/326, 356/328
• US Class Current: 356/243.1
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/0294 adapted to provide an additional optical effect, e.g. anti-reflection or filter
• CPC Class Codes: G02B 7/008 with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation

Abstract

The present invention provides a thermally stable reference member comprising, at least one radiation attenuating element and at least one radiation scattering element. The radiation attenuating element comprising at least one aperture for transmission of radiation therethrough. The attenuating and scattering elements placed in series so that radiation transmitted through the reference member passes through each of the attenuating and scattering elements. The attenuating and scattering elements of the reference member may further comprise a thermally stable mount to hold the elements in a selected position relative to each other, and in relation to an instrument, or the elements may be bonded together. The radiation attenuating element may be comprised of a material selected from the group consisting of INVAR, tungsten, brass, and a material substantially non-transparent for incident radiation, and the radiation scattering element may be comprised of a radiation scattering material selected from the group consisting of opalescent glass, SPECTRALON, PTFE, ZERODUR, fused silica, quartz, sapphire, diamond, and a transparent material with essentially low thermal expansion.

Claims

1. A radiation attenuating and scattering reference member with improved thermal stability comprising:

one, or more than one partially or totally radiation attenuating element comprising at least one aperture for transmission of radiation therethrough, and

one, or more than one radiation scattering element,

wherein said radiation attenuating and scattering elements are placed in series so that radiation transmitted through said reference member passes through each of said attenuating and scattering elements.

2. The reference member of claim 1, further comprising a mount to hold said radiation attenuating element and said scattering element in a selected position relative to each other within said mount, and in relation to an instrument.

3. The reference member of claim 1, wherein said one, or more than one attenuating element and said one, or more than one scattering element are bonded together.

4. The reference member according to claim 1, wherein said radiation attenuating element comprises two, or more than two apertures for transmission of radiation therethrough.

5. The reference member according to claim 3, wherein said radiation attenuating element comprises two, or more than two apertures for transmission of radiation therethrough.

6. The reference member according to claim 4, wherein said radiation attenuating element is formed of a material that partially or totally blocks, absorbs, reflects, back scatters or a combination thereof, any incident radiation.

7. The reference member according to claim 6, wherein said material is selected from the group consisting of INVAR, tungsten, brass, and a material substantially non-transparent for incident radiation.

8. The reference member according to claim 1, wherein said radiation scattering element comprises a radiation volume scattering material selected from the group consisting of opalescent glass, SPECTRALON, PTFE, and a material whose surface may be modified to scatter radiation selected from the group consisting of ZERODUR, fused silica, quartz, sapphire, diamond, and a transparent material with substantially low thermal expansion.

9. The reference member according to claim 2, wherein said radiation scattering element is formed of a volume radiation scattering material selected from the group consisting of opalescent glass, SPECTRALON, PTFE, and a material whose surface may be modified to scatter incident radiation in a random or controlled fashion, selected from the group consisting of ZERODUR, fused silica, quartz, sapphire, diamond, and a transparent material with substantially low thermal expansion.

10. The reference member according to claim 8, wherein said radiation scattering element comprises an electromagnetic radiation scattering structure on one or both surfaces.

11. The reference member according to claim 9, wherein said radiation scattering element comprises an electromagnetic radiation scattering structure on one or both surfaces.

12. The reference member according to claim 1, wherein said radiation attenuating element and said scattering element are in the form of plates.

13. The reference member according to claim 3, wherein said radiation attenuating element and said scattering element are in the form of plates.

15. The reference member according to claim 1, wherein said radiation attenuating element is made of radiation non-transparent foil comprising a plurality of openings, said openings having a diameter and spaced apart in a manner suitable to achieve a required attenuation of incident radiation.

16. The reference member according to claim 1, wherein said radiation attenuating element comprises one aperture.

17. The reference member according to claim 8 wherein said radiation attenuating element comprises one aperture.

23. The reference member of claim 1, wherein said reference member comprises a plurality of radiation attenuation elements and a plurality of radiation scattering elements.

24. A method for attenuating electromagnetic radiation comprising;

i) providing a source of electromagnetic radiation;

ii) placing the reference member according to claim 1 between said source of electromagnetic radiation and a detector to produce an attenuated electromagnetic beam; and

iii) detecting said beam at said detector.

25. The method according to claim 23 wherein said reference member is adjusted to match scattering and attenuation characteristics of a given sample.

26. A method for calibrating a spectrometer comprising, placing the reference member according to claim 1 between a source of electromagnetic radiation and a detector to produce an attenuated electromagnetic beam, measuring the absorbance of said reference member, and adjusting said spectrometer.

14. A reference member comprising one, or more than one radiation attenuating element made from INVAR, adjacent to and in series with, at least one thermally stable scattering element made from ZERODUR.

18. A radiation attenuating and scattering reference member with improved thermal stability comprising, a radiation attenuating-scattering element comprising a first, and a second surface, wherein a portion of said radiation attenuating-scattering element is opaque to electromagnetic radiation and comprises one, or more than one aperture for transmission of radiation there through, and wherein said second surface is modified to scatter electromagnetic radiation.

19. The radiation attenuating and scattering reference member of claim 18, wherein said radiation attenuating-scattering element comprises a volume scattering material selected from the group consisting of opalescent glass, light scattering ceramic, TEFLON®

, PTFE, SPECTRALON.

20. The radiation attenuating and scattering reference member of claim 18, wherein said radiation attenuating-scattering element comprises a partially or totally radiation non-absorbing thermally stable material, whose surface can be modified to scatter incident radiation in a random or controlled fashion, said thermally stable material selected from the group consisting of ZERODUR, fused silica, quartz, sapphire, diamond, low expansion glass and a non-absorbing material with low thermal expansion, and wherein said first surface is covered with an electromagnetic radiation opaque layer.

21. The radiation attenuating and scattering reference member of claim 20, wherein said electromagnetic radiation opaque layer is selected from the group consisting of chromium, alloy of nickel, alloy of chromium, aluminum, silver, gold, and a material that is non-transparent to light.

22. The radiation attenuating and scattering reference member of claim 18, wherein said second surface is ground, etched or otherwise processed to scatter incident radiation in a random or controlled fashion.