Small detector array for infrared imaging microscope

• US 20020033452A1
• Filed: 08/29/2001
• Published: 03/21/2002
• Est. Priority Date: 08/29/2000
• Status: Active Grant

• Current Assignee: PerkinElmer Singapore Pte Ltd. (Revvity, Inc.)
• Original Assignee: PerkinElmer Singapore Pte Ltd. (Revvity, Inc.)
• Inventors: Turner, Andrew James, Hoult, Robert Alan
• Granted Patent: US 7,378,657 B2
• Time in Patent Office: Days
• US Class Current: 250/332
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G02B 21/06 Means for illuminating specimens
• CPC Class Codes: G02B 21/361 Optical details, e.g. image relay to the camera or image sensor G02B21/364 takes precedence; illumination details G02B21/06 and subgroups
• CPC Class Codes: G02B 21/365 Control or image processing arrangements for digital or video microscopes G02B21/361, G02B21/362 take precedence

Abstract

An infrared imaging microscope, particularly of the type used to carry out FT-IR measurement, has a detector in the form of a small detector array (85) of individual detector elements (86). The outputs of the detector elements (86) are fed in parallel to processing means which process the output signals. The use of a small array means that the outputs can be processed without the need for complex multiplexing or perhaps no multiplexing at all thus avoiding the reduction in signal to noise ratio which is associated with large scale multiplexing. The small detector array will generally have between 3 and 100 detector elements. Typically the upper limit will be 64 and a preferred arrangement has 16 detector elements.

Claims

1. An IR microscope comprising a sample stage, optical components for guiding analysing radiation so that it is incident on a sample to be analysed which is carried on said stage, and for guiding radiation from the sample to a detector, wherein said detector comprises a small array of individual detector elements, the outputs of the detector elements being fed in parallel to processing means for processing the detector element outputs.

2. A microscope according to claim 1, wherein each detector element has its own associated detector circuitry.

3. A microscope according to claim 1 or claim 2, wherein the detector elements are arranged in a linear array.

4. A microscope according to claim 3, wherein the detecting elements of the linear array are spaced apart.

5. A microscope according to any preceding claim, wherein the detector elements are arranged in a plurality of rows.

6. A microscope according to claim 5, wherein the detector elements in each row are spaced apart and said rows are spaced apart.

7. A microscope according to claim 5 or claim 6, wherein the detector elements in each row are offset relative to those in a next adjacent row.

8. A microscope according to any preceding claims, wherein the centre of each element is located at a position corresponding to a point on a regular grid.

9. A microscope according to claim 8, wherein the grid pattern is square or rectangular.

10. A microscope according to claim 8 or claim 9, wherein the spacing between the centres of elements in each row corresponds to a multiple of the spacing of the points on the grid.

11. A microscope according to claims 7 and 8, wherein the offset in detector element position in adjacent rows corresponds to the spacing of the grid or a multiple of that spacing.

12. A microscope according to any one of claims 8 to 11 wherein the dimensions of each detector element are substantially equal to the spacing of the points on the grid.

13. A microscope according to any preceding claim, including, in addition to said detector array, a single detector element, said processing means being arranged to process output signals received from either said array or said single detector element.

15. A detector array according to claim 14, wherein the detector elements are arranged in a linear array.

16. A detector array according to claim 14, wherein the detector elements of the linear array are spaced apart.

18. A detector array according to claim 17, wherein the detector elements in each row are spaced apart, and the rows are spaced apart.

19. A detector array according to claim 17 or claim 18, wherein the detector elements in each row are offset relative to those in a next adjacent row.

23. A detector array according to claim 19 or claim 20 wherein the offset in detector element position in adjacent rows corresponds to the spacing of the grid or a multiple of that spacing.

28. A microscope according to any one of claims 1 to 10 including an assembly which can be moved into or out of the beam of radiation in order to change the magnification provided by the optical elements of the microscope.

34. A microscope according to any one of claims 28 to 33, wherein the magnifying assembly is movable between an operative and an inoperative condition by rotation about an axis.

37. A microscope according to any one of claims 28 to 36 including a shield for shielding the detector from unwanted radiation, said shield being switchable between an operative and an inoperative position.

14. A detector array for use in a IR microscope, said detector array comprising a plurality of individual detector elements, each corresponding to a pixel, which are disposed in spaced relationship, the centre to centre spacing of adjacent elements being substantially equal to or a multiple of the pixel pitch.

17. A detector array according to any one of claims 14 to 16, wherein the detector elements are arranged in a plurality of rows.

20. A detector array according to any one of claims 14 to 19, wherein the detector elements are arranged such that the centre of each element is located at a position corresponding to a point on a regular grid.

21. A detector array according to claim 20, wherein the grid pattern is square or rectangular.

22. A detector array according to claim 20 or claim 21, wherein the spacing between the centres of the elements in each row corresponds to a multiple of the spacing of the points of the grid.

24. A detector array according to any one of claims 20 to 23, wherein the dimensions of each detector element are substantially equal to the spacing of the points of the grid.

26. A detector assembly according to claim 25, where the detector elements are located in a Dewar type vessel.

27. A detector assembly according to claim 25 or claim 26, wherein said array comprises an array according to any one of claims 14 to 24.

29. A microscope according to claim 28, wherein said magnifying assembly is located between the objective mirror of the microscope and its intermediate focus.

30. A microscope according to claim 28 or claim 29, wherein the magnifying assembly includes a reflecting element which in its operative position reflects the beam of radiation away from its normal direction of propagation and a magnifying component or components which can receive the reflected radiation.

31. A microscope according to claim 30, wherein the magnifying assembly includes first and second magnifying components, the first of which receives radiation from the reflecting element and the second of which receives the radiation from the first magnifying component, and a second reflecting element for directing radiation from the second magnifying component along its normal direction of propagation.

32. A microscope according to claim 31, wherein the first and second magnifying components comprise spherical mirrors.

33. A microscope according to claim 31 or claim 32, wherein the first and second reflecting elements are plane mirrors.

35. A microscope according to any one of claims 30 to 34, wherein the assembly is movable between an operative position in which the reflecting element is located in the beam of radiation and an inoperative position in which the radiation can propagate to the detector elements without magnification by the magnifying assembly by rotation about an axis through the first and second components.

36. A microscope according to claim 34 or claim 35, wherein the angle of rotation through which the assembly can be rotated is of the order of 90°

.

38. A microscope according to claim 37 when dependent upon any one or claims 31 to 36, wherein the shield comprises an element disposed along the propagation path of radiation reflected from the first magnifying component to the second magnifying component, said element having therein an aperture and acting as a cold shield to prevent unrequited radiation arriving at the detector.

39. A microscope according to claim 38, wherein said element comprises a plane mirror which allows through the aperture a beam of rays to be detected but blocks rays outside that beam.

25. A detector assembly for an infrared microscope comprising a small array of individual detector elements the outputs of which can be fed in parallel to a processing means, in combination with a single detector element.