Oscillating mechanism driven monochromator

• US 6,587,196 B1
• Filed: 01/26/2000
• Issued: 07/01/2003
• Est. Priority Date: 01/26/2000
• Status: Expired due to Fees

• Current Assignee: GLT Acquisition Corporation
• Original Assignee: Sensys Medical, Inc. (Sensys Medical Limited)
• Inventors: Stippick, Tim, Meissner, Ken, Acosta, George
• Primary Examiner(s): Smith, Zandra V.
• Application Number:
  US09/491,350
• Time in Patent Office: 1,252 Days
• Field of Search: 356/334, 356/308, 356/326, 356/331
• US Class Current: 356/308
• CPC Class Codes: G01J 3/06 Scanning arrangements arrangements for order-selection

Abstract

The invention provides a mechanism for oscillating the spectral grating of a monochromator. The mechanism couples the spectral grating of the monochromator to an oscillating spatial linkage mechanism which accepts a rotational input and converts it into an oscillatory motion. A monochromator according to the invention comprises an oscillating grating that is oscillated by such spacial linkage mechanism drive.

Claims

1. An apparatus for oscillating a spectral dispersing element of a monochromator, comprising:

a spatial linkage mechanism for accepting a rotational input from a motive source and converting said rotational input into an oscillatory motion, said spatial linkage mechanism comprising;

a first coupler for receiving said rotational input directly from said motive source, said first coupler rotating in accordance therewith;

a link coupled to said first coupler; and

a second coupler coupled to said link;

wherein said link translates said rotational input of said motive source, as supplied thereto by said first coupler, to said oscillatory motion;

said link imparts said oscillatory motion to said second coupler, and said second coupler oscillates said spectral element.

2. The apparatus of claim 1, wherein said first coupler defines an aperture that is rotated off axis from a rotational axis of said motive source.

3. The apparatus of claim 2, said link further comprising:

a projection that is formed on said link and that is adapted for engagement with the aperture of said first coupler, wherein said projection and said aperture are arranged to move freely, one relative to the other.

4. The apparatus of claim 1, wherein said first coupler is bent away from said motive source at a predetermined angle.

5. The apparatus of claim 3, further comprising:

a bushing or bearing for reducing friction between said link and said first coupler at a projection/aperture interface.

6. The apparatus of claim 1, wherein said link comprises a U-shaped member.

7. The apparatus of claim 1, wherein said link defines an aperture in each of two projecting segments, and wherein said link is configured to receive opposing, cylindircal projections that are formed on said second coupler.

8. The appartus of claim 1, wherein said first coupler is affixed to, or formed integrally with, a spectral element drive shaft.

9. The apparatus of claim 7, further comprising:

a bushing or bearing for reducing friction between said link and said second coupler at a projection/aperture interface.

10. The apparatus of claim 1, wherein said spatial linkage mechanism oscillates said spectral element through one complete forward and reverse cycle for every one revolution of a shaft of said motive element.

11. The apparatus of claim 1, wherein the geometry of said spatial mechanism determines the number of oscillations of said spectral element per input revolution and the angle of oscillation.

12. The apparatus of claim 1, wherein 180 degrees of rotational input completes a first scan of said spectral element in a first direction;

and wherein a next 180 degrees of rotational input completes a second scan of said spectral element in a second, opposite direction.

13. The apparatus of claim 1, wherein any of a plurality of velocity profiles can be imparted to said motive source to produce a desired output velocity profile for said spectral element.

14. The apparatus of claim 13, wherein said output velocity profile is a constant velocity profile of said spectral element throughout an oscillation angle.

15. The apparatus of claim 1, further comprising:

an optical encoder for defining the postion of said spectral element.

16. The apparatus of claim 1, wherein the position of said spectral element is analytically determined by the geometry of said spatial mechanism and a known angular position of said motive source.

17. The apparatus of claim 16, wherein said analytical determination is made by any of counting steps, coupling an encoder to said motive source, and directly coupling to said second coupler to measure the angular position of said spectral element.

18. The appartus of claim 1, wherein said first coupler defines a slot along which a bushing may be positioned to increase or decrease, as desired, the extent to which said first coupler pulls said link from side to side during each rotation of said rotational input.

19. The apparatus of claim 1, wherein said spatial linkage mechanism is adapted to produce multiple oscillations during each rotation of said rotational input.

20. The apparatus of claim 1, wherein said spatial linkage mechanism is adapted to produce a fractional oscillation during each rotation of said rotational input.

21. The apparatus of claim 1, wherein said spectral element comprises any of a ruled spectral grating, a holographic grating, multiple gratings in which a plurality of gratings are coupled to a same output of said spatial linkage mechanism to allow said grating to be rotated with a same (or offset) angular position, and a prism.

22. The apparatus of claim 1, wherein said spatial linkage mechanism is used in a monochromator having a fixed spectral element and an oscillating mirror, wherein the mirror is coupled to said spatial linkage mechanism.

23. The apparatus of claim 1, wherein said first coupler further comprises a harmonic balancer.

24. An apparatus for oscillating a spectral element of a monochromator, comprising:

a spatial linkage mechanism for accepting a rotational input from a motive source and converting said rotational input into an oscillatory motion, said spatial linkage mechanism comprising;

a first coupler for receiving said rotational input, said first coupler rotating in accordance therewith, wherein said first coupler defines an aperture that is rotated off axis from a rotational axis of said motive source, wherein said first coupler is affixed to, or formed integrally with, a spectral element drive shaft;

a link coupled to said first coupler, said link further comprising a projection that is formed on said link and that is adapted for engagement with the aperture of said first coupler, wherein said projection and said aperture are arranged to move freely, one relative to the other, wherein said link comprises a U-shaped member, wherein said link defines an aperture in each of two projecting segments, and wherein said link is configured to receive opposing, cylindircal projections that are formed on said second coupler; and

a second coupler coupled to said link;

wherein said link translates said rotational input of said motive source, as supplied thereto by said first coupler, to said oscillatory motion;

said link imparts said oscillatory motion to said second coupler, and said second coupler oscillates said spectral element.

25. The apparatus of claim 24, wherein said spatial linkage mechanism oscillates said spectral element through one complete forward and reverse cycle for every one revolution of a shaft of said motive element.

26. The apparatus of claim 24, wherein said spatial linkage mechanism is adapted to produce multiple oscillations during each rotation of said rotational input.

27. The apparatus of claim 24, wherein said spatial linkage mechanism is adapted to produce a fractional oscillation during each rotation of said rotational input.

28. The apparatus of claim 24, wherein said spectral element comprises any of a ruled spectral grating, a holographic grating, multiple gratings in which a plurality of gratings are coupled to a same output of said spatial linkage mechanism to allow said grating to be rotated with a same (or offset) angular position, and a prism.

29. The apparatus of claim 24, wherein said spatial linkage mechanism is used in a monochromator having a fixed spectral element and an oscillating mirror, wherein the mirror is coupled to said spatial linkage mechanism.