Infrared radiation detector

• US 6,111,254 A
• Filed: 11/22/1989
• Issued: 08/29/2000
• Est. Priority Date: 07/14/1986
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Aspen Systems Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Eden, Dayton D.
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US07/451,715
• Time in Patent Office: 3,933 Days
• Field of Search: 250/332, 250/338.4, 250/338.1, 357/30.11, 257/258, 257/275, 257/442, 257/448, 343/721, 343/727, 343/793
• US Class Current: 250/338.1
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0837 Microantennas, e.g. bow-tie
• CPC Class Codes: G01J 5/10 using electric radiation detectors
• CPC Class Codes: H01L 27/14669 Infrared imagers
• CPC Class Codes: H01L 31/0224 Electrodes
• CPC Class Codes: H01L 31/09 Devices sensitive to infrared, visible or ultraviolet radiation H01L31/101 takes precedence
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence
• CPC Class Codes: H01Q 9/16 with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence

Abstract

An infrared radiation detector is disclosed which is fabricated on a dielectric substrate. The detector utilizes photosensitive segments which are included within elongate members disposed on the surface of the substrate. The elongate members comprise photosensitive detector segments which are located between and contact non-photosensitive segments and the entirety of each strip is electrically conductive. The elongate members are preferably offset from each other by less than the wavelength of the radiation and the photosensitive segments within the elongate members are also preferably spaced apart by less than the wavelength of the radiation. A reflective plane, typically an aluminum layer, is offset from the plane of the detector segments by less than the wavelength of the radiation. Incident radiation is captured by the overall detector structure which includes the reflective plane and the elongate members which include both photosensitive and non-photosensitive segments. The radiation power is transferred to the photosensitive detector segments to produce a detection signal. The detection signals are combined along the length of the elongate members and conveyed through electrical conductors at the ends of the members to produce a composite radiation detection signal. A plurality of the detectors can be combined to produce an infrared imager.

Claims

1. A detector for infrared radiation, comprising:

a plurality of elongate, segmented, electrically conductive members, each member comprising a plurality of photosensitive segments responsive to said infrared radiation and a plurality of non-photosensitive segments which are not responsive to said infrared radiation, said photosensitive segments having each of the linear dimensions thereof less than the wavelength of said infrared radiation,

said photosensitive segments and said non-photosensitive segments positioned alternately and electrically connected in series to form each of said members,

a plane reflective to said infrared radiation, said plane offset from said photosensitive segments by less than the wavelength of said radiation, and

electrical conductors connected to said elongate, segmented, electrically conductive members for conveying signals produced by said photosensitive segments in response to said infrared radiation.

2. A detector for infrared radiation as recited in claim 1 wherein said photosensitive elements are spared apart along said elongate members by less than the wavelength of said radiation.

3. A detector for infrared radiation as recited in claim 1, wherein said elongate members are spaced apart by less than the wavelength of said radiation.

4. A detector for infrared radiation as recited in claim 1 wherein said photosensitive and said non-photosensitive segments have substantially the same dielectric constant.

5. A detector for infrared radiation as recited in claim 1 wherein said conductive members are parallel to each other.

6. A detector for infrared radiation as recited in claim 1 wherein said plane is a layer of aluminum.

7. A detector for infrared radiation as recited in claim 1 wherein the wavelength of said infrared radiation is in the band of 8-12 microns.

8. A detector for infrared radiation as recited in claim 1, wherein said photosensitive segments comprise mercury cadmium telluride having an alloy ratio of x equal to approximately 0.15.

9. A detector for infrared radiation as recited in claim 1 wherein said non-photosensitive segments are mercury cadmium telluride having an alloy ratio of x equal to or greater than 0.2.

10. A detector for infrared radiation as recited in claim 1 including a plurality of parallel conductors positioned on the opposite side of said photosensitive segments from said reflective plane and spaced offset from said photosensitive segments by less than the wavelength of said radiation, and said parallel conductors spaced apart from each other by less than the wavelength of said radiation.

11. A detector for infrared radiation as recited in claim 1 wherein said photosensitive segments comprise a dielectric material which absorbs and conducts said infrared radiation.

12. A detector for infrared radiation as recited in claim 1 wherein said photosensitive segments have a dielectric index n of approximately 3.6.

13. A detector for infrared radiation as recited in claim 1 wherein said non-photosensitve segments comprise a material which does not absorb said infrared radiation.

14. A detector for infrared radiation as recited in claim 1 wherein said non-photosensitive segments have a dielectric index n of approximately 23.6.

15. A detector for infrared radiation comprising:

a plurality of elongate, segmented, electrically conductive members, each member comprising a plurality of photosensitive segments responsive to said infrared radiation and a plurality of non-photosensitive segments which are not responsive to said infrared radiation, and said conductive members being spaced apart by less than the wavelength of said infrared radiation,

said photosensitive segments and said non-photosensitive segments positioned alternately and electrically connected in series to form each of said members, said photosensitive segments in each said member being spaced apart by less than the wavelength of said infrared radiation,

a plane reflective to said infrared radiation, said plane offset from said photosensitive segments by less than the wavelength of said infrared radiation, and

electrical conductors connected to said elongate, segmented, electrically conductive members for conveying signals produced by said photosensitive segments in response to said infrared radiation.

16. A detector for infrared radiation as recited in claim 15 wherein said photosensitive and said non-photosensitive segments have substantially the same dielectric constant.

17. A detector for infrared radiation as recited in claim 15 wherein said elongate conductive members are parallel to each other.

18. A detector for infrared radiation as recited in claim 15 wherein said photosensitive segments comprise a dielectric material which absorbs and conducts said infrared radiation.

19. A detector for infrared radiation as recited in claim 15 wherein said plane is a layer of aluminum.

20. A detector for infrared radiation as recited in claim 15 wherein the wavelength of said infrared radiation is in the band of 8-12 microns.

21. A detector for infrared radiation as recited in claim 15 wherein said photosensitive segments are mercury cadmium telluride having an alloy ratio of X equal to approximately 0.15.

22. A detector for infrared radiation as recited in claim 15 wherein said non-photosensitive segments are mercury cadmium telluride having an alloy ratio of X equal to or greater than 0.2.

23. A detector for infrared radiation as recited in claim 15 including a plurality of parallel conductors positioned on the opposite side of said photosensitive segments from said reflective plane and spaced offset from said photosensitive segments by less than the wavelength of said radiation, and said parallel conductors spaced apart from each other by less than the wavelength of said radiation.

24. A detector for infrared radiation as recited in claim 15 wherein said non-photosensitive segments comprise a material which does not absorb said infrared radiation.

25. A detector for infrared radiation as recited in claim 15 wherein said photosensitive segments have a dielectric index n of approximately 3.6.

26. A detector for infrared radiation as recited in claim 15 wherein said non-photosensitive segments have a dielectric index n of approximately 3.6.

27. A detector for infrared radiation comprising:

a substrate;

a plurality of non-conductive segments on said substrate,

a plurality of electrically conductive, elongate members supported on said nonconductive segments and spaced apart by less than the wavelength of said radiation, each said member comprising a plurality of photosensitive detector segments spaced apart along the member by less than the wavelength of said radiation, with non-photosensitive segments separating said photosensitive segments, said photosensitive and said non-photosensitive segments having substantially the same dielectric constant,

a radiation reflecting plane offset from said elongate members by less than the wavelength of said radiation, wherein said radiation is captured by said radiation detector and power of said radiation is conveyed to said photosensitive detector segments which produce detection signals therefrom, and electrical conductors connected to said elongate members for conveying said detection signals produced by said photosensitive detector segments.

28. A detector for infrared radiation as recited in claim 27 wherein said elongate, conductive members are parallel to each other.

29. A detector for infrared radiation as recited in claim 27 wherein said photosensitive segments comprise a dielectric material which absorbs and conducts infrared radiation.

30. A detector for infrared radiation as recited in claim 27 wherein said photosensitive detector segments have a dielectric index n of approximately 3.6.

31. A detector for infrared radiation as recited in claim 27 wherein said photosensitive and said non-photosensitive segments have substantially the same dielectric constant.

32. A detector for infrared radiation as recited in claim 27 wherein said plane is a layer of aluminum.

33. A detector for infrared radiation as recited in claim 27 wherein said non-photosensitive segments have a dielectric index n of approximately 3.6.

34. A detector for infrared radiation as recited in claim 27 wherein said non-photosensitive segments comprise a dielectric material which does not absorb said infrared radiation.

35. A detector for infrared radiation as recited in claim 27 wherein said photosensitive segments comprise mercury cadmium telluride having an alloy ratio of X equal to approximately 0.15.

36. A detector for infrared radiation as recited in claim 27 wherein said non-photosensitive segments comprise mercury cadmium telluride having an alloy ratio X equal to or greater than 0.2.

37. A detector for infrared radiation comprising;

a plurality of electrically conductive, elongate members supported on said substrate and spaced apart by less than the wavelength of said radiation, each said member comprising a plurality of photosensitive detector segments which are responsive to said infrared radiation and are spaced apart along the member by less than the wavelength of said radiation, with non-photosensitive segments which are not responsive to said radiation separating said photosensitive segments, said photosensitive and said non-photosensitive segments having substantially the same dielectric constant,

a radiation reflecting plane offset from said elongate members by less than the wavelength of said radiation, wherein said radiation is captured by said photosensitive detector and power of said radiation is conveyed to said detector segments which produce detection signals therefrom,

a plurality of elongate, electrically conductive, non-photosensitive members spaced apart by less than the wavelength of said radiation and offset in a plane from said elongate members by less than the wavelength of said radiation, and

electrical conductors connected to said elongate members having photosensitive segments for conveying said detection signals produced by said photosensitive detector segments.

38. A detector for infrared radiation as recited in claim 37 wherein said elongate members having photosensitive segments are parallel to each other.

39. A detector for infrared radiation as recited in claim 37 wherein said elongate, non-photosensitive members are on the opposite side of said elongate members having photosensitive segments from said reflecting plane.

40. A detector for infrared radiation as recited in claim 37 wherein said non-photosensitive members are parallel to each other.

41. A detector for infrared radiation as recited in claim 37 wherein said photosensitive detector segments have a dielectric constant n of at least 3.6.

42. A detector for infrared radiation as recited in claim 37 wherein said photosensitive detector segments are dielectrics which absorb and conduct infrared radiation.

43. A detector for infrared radiation as recited in claim 37 wherein said non-photosensitive segments are dielectrics which do not absorb infrared radiation.

44. A detector for infrared radiation as recited in claim 37 wherein said photosensitive detector segments have a dielectric constant n of at least 3.6.

45. An infrared detector array for producing an infrared image from infrared radiation comprising:

a plurality of infrared detectors positioned in a planar array, each detector comprising;

a plurality of elongate, segmented, electrically conductive members, each member comprising a plurality of photosensitive segments responsive to said infrared radiation and a plurality of non-photosensitive segments which are not responsive to said infrared radiation, and said conductive members spaced apart by less than the wavelength of said infrared radiation,

said photosensitive segments and said non-photosensitive segments positioned alternately and electrically connected in series to form each of said members, said photosensitive segments in each said member spaced apart by less than the wavelength of said infrared radiation,

a plane reflective to said infrared radiation, said plane offset from said photosensitive segments by less than the wavelength of said infrared radiation, and

electrical conductors connected to said elongate, segmented, electrically conductive members for extracting signals produced by said photosensitive segments in response to said infrared radiation.

46. An infrared detector array for producing an infrared image from infrared radiation comprising:

a plurality of infrared detectors positioned in a planar array, each detector comprising;

a substrate;

a plurality of electrically conductive, elongate members supported on said substrate and spaced apart by less than the wavelength of said radiation, each said member comprising a plurality of photosensitive detector segments spaced apart along the member by less than the wavelength of said radiation, with non-photosensitive segments separating said photosensitive segments, said photosensitive and said non-photosensitive segments having substantially the same dielectric constant

a radiation reflecting plane offset from said elongate members by less than the wavelength of said radiation, wherein said radiation is captured by said radiation detector and power of said radiation is conveyed to said photosensitive detector segments which produce detection signals therefrom, and

electrical conductors connected to said elongate members for conveying said detection signals produced by said photosensitive detector segments.

47. An infrared detector array for producing an infrared image from infrared radiation comprising:

a plurality of infrared detectors positioned in a planar array, each detector comprising;

a plurality of electrically conductive, elongate members supported on said substrate and spaced apart by less than the wavelength of said radiation, each said member comprising a plurality of photosensitive detector segments which are responsive to said infrared radiation and are spaced apart along the member by less than the wavelength of said radiation, with non-photosensitive segments which are not responsive to said radiation separating said photosensitive segments, said photosensitive and said non-photosensitive segments having substantially the same dielectric constant,

a radiation reflecting plane offset from said elongate members by less than the wavelength of said radiation, wherein said radiation is captured by said photosensitive detector and power of said radiation is conveyed to said detector segments which produce detection signals therefrom,

a plurality of elongate, electrically conductive, non-photosensitive members spaced apart by less than the wavelength of said radiation and offset from said elongate members by less than the wavelength of said radiation, and

electrical conductors connected to said elongate members having photosensitive segments for conveying said detection signals produced by said photosensitive detector segments.

48. A detector for infrared radiation comprising:

a dielectric substrate,

an array of insulating blocks on the surface of said substrate, said insulating blocks organized in elongate groups, wherein the insulating blocks in each group are spaced apart by less than the wavelength of said infrared radiation and said groups are spaced apart by less than said wavelength,

a plurality of photosensitive segments positioned respectively on the surfaces of said insulating blocks, said photosensitive segments having essentially the same lateral dimensions as said insulating blocks and have a thickness less than said wavelength,

a plurality of electrically conducting bridging segments for respectively connecting pairs of said photosensitive segments within said groups for producing a plurality of elongate, conducting members comprising alternating ones of photosensitive segments and said conducting bridging segments,

a reflecting plane positioned on the opposite side of said substrate from said photosensitive segments and offset from said photosensitive segments by a distance less than said wavelength, and

first and second electrical conductors connected to each of said elongate, conducting members for providing a conduction path for detection signals produced by said photosensitive segments in response to said infrared radiation.

49. A detector for infrared radiation as recited in claim 48 wherein there is a heterojunction at each interface between said photosensitive segments and said electrically conducting bridge segments.

50. A detector for infrared radiation as recited in claim 48 wherein there is a blocking junction at each interface between said photosensitive segments and said insulating blocks.

51. A detector for infrared radiation as recited in claim 48 wherein said elongate members are parallel to each other.

52. A detector for infrared indication as recited in claim 48 including a plurality of parallel conductors positioned above said photosensitive segments by less than the wavelength of said indication, spaced apart from each other by less than said wavelength and aligned perpendicular to said elongate groups.

53. A nonpolarized detector for infrared radiation comprising:

a dielectric substrate,

an array of insulating blocks on the surface of said substrate, said insulating blocks comprising first and second sets each having a plurality of groups of said blocks, each group comprising an elongate collection of said blocks, wherein the groups in said first set are parallel to each other and the groups in said second set are parallel to each other and said groups in said first and second sets are perpendicular to each other, wherein the insulating blocks in each group are spaced apart by less than the wavelength of said infrared radiation and said parallel groups are spaced apart by less than the wavelength of said radiation,

a plurality of photosensitive segments positioned respectively on the surfaces of said insulating blocks, said photosensitive segments having essentially the same lateral dimensions as said insulating blocks and have a thickness less than said wavelength,

a plurality of X-shaped electrically conducting bridging segments for respectively connecting a pair of adjacent ones of said photosensitive segments from within said first set to an adjacent pair of said photosensitive segments from within said second set for producing a plurality of elongate, conducting members comprising alternating ones of photosensitive segments and said conducting bridging segments, a half of said conducting members parallel to each other and perpendicular to the other half of said conducting members, which are parallel to each other,

a reflecting plane positioned on the opposite side of said substrate from said photosensitive segments and offset from said photosensitive segments by a distance less than said wavelength, and

first and second electrical conductors connected to each of said elongate, conducting members for providing a conduction path for detection signals produced by said photosensitive segments in response to said infrared radiation.

54. A nonpolarized detector for infrared radiation as recited in claim 53 wherein there is a heterojunction at each interface between said photosensitive segments and said electrically conducting bridge segments.

55. A nonpolarized detector for infrared radiation as recited in claim 53 wherein there is a blocking junction at each interface between said photosensitive segments and said insulating blocks.