Infrared radiation-burglary detector

• US 4,081,680 A
• Filed: 11/04/1976
• Issued: 03/28/1978
• Est. Priority Date: 06/21/1976
• Status: Expired due to Term

• Current Assignee: Cerberus ABP Investor LLC (Cerberus Capital Management LP)
• Original Assignee: Cerberus ABP Investor LLC (Cerberus Capital Management LP)
• Inventors: Keller, Hansjurg
• Primary Examiner(s): Borchelt, Archie R.
• Application Number:
  US05/738,909
• Time in Patent Office: 509 Days
• Field of Search: 250/338, 250/340, 250/342, 250/353, 350/1, 350/2, 340/258 D
• US Class Current: 250/342
• CPC Class Codes: G02B 5/10 with curved faces
• CPC Class Codes: G08B 13/193 using focusing means
• CPC Class Codes: Y10S 250/01 Passive intrusion detectors

Abstract

An infrared radiation-burglary detector comprising a number of reflector surfaces which focus the radiation incident from different separate receiving regions upon a common radiation receiver. The reflector surfaces are arranged and aligned such that the intersection locations of the receiving regions, viewed in the radiation direction, are located behind the front of the detector.

Claims

1. An infrared radiation-burglary detector comprising a common radiation receiver for different receiving regions, a number of reflector surfaces focusing the radiation arriving from the different receiving regions upon the common radiation receiver, said reflector surfaces being arranged and aligned such that any intersection locations of the receiving regions, viewed in the irradiation direction, are located behind the front of the detector, so that there is prevented focusing of radiation upon said common radiation receiver from an object disposed at any location in front of the detector by more than one of said reflector surfaces.

2. The detector as defined in claim 1, wherein given ones of said reflector surfaces are located externally of the lengthwise axis of the detector and aligned such that the angle formed by their main normal with such lengthwise axis lies outside of the angular range between the incident angle of the radiation arriving at the radiation receiver formed with the lengthwise axis and one-half of such angle.

3. The detector as defined in claim 1, wherein each of the reflector surfaces comrpise paraboloids of revolution.

4. The detector as defined in claim 3, wherein at least given ones of the reflector surfaces are located externally of the lengthwise axis of the detector, said externally located reflector surfaces comprising eccentric sections of paraboloids of revolution, the respective axis of which is aligned essentially parallel to the momentary receiving direction.

5. The detector as defined in claim 1, wherein the reflector surfaces each comprise double-curved surfaces possessing different main radii of curvature, the radiation receiver is arranged substantially at the focal point of a main section of the associated individual reflector surfaces.

6. The detector as defined in claim 1, wherein the reflector surfaces each comprise a substantially spherical surface, and a cylindrical lense arranged at the front of the detector.

7. The detector as defined in claim 6, wherein the cylindrical lense comprises an echelon lense.

8. The detector as defined in claim 1, wherein the reflector surfaces each comprise a substantially paraboloid-shaped surface, and a cylindrical lense arranged at the front of the detector.

9. The detector as defined in claim 7, wherein the cylindrical lense comprises an echelon lense.

10. The detector as defined in claim 1, wherein each reflector surface comprises a substantially cylindrical surface.

11. The detector as defined in claim 1, wherein the reflector surfaces comprise portions of a cylinder surface, radiation-absorbing strips mounted at the surface of said cylinder surface, the radiation receiver being arranged at the focal line of the cylinder surface.

12. The detector as defined in claim 11, wherein the radiation-absorbing strips comprise displaceable strips.

13. The detector as defined in claim 1, further including a filter arranged at the front of the detector.

14. The detector as defined in claim 13, wherein said filter is permeable to infrared radiation in a predetermined spectral range.

15. The detector as defined in claim 13, wherein the filter has a front face structured such that radiation of a wavelength falling outside of a predetermined infrared-throughpass range is at least partially reflected.

16. The detector as defined in claim 1, further including diaphragm means having openings and arranged forwardly of the front of the detector and aligned such that the openings thereof only permit passage of radiation emanating from predetermined receiving directions.

17. The detector as defined in claim 16, wherein the diaphragm means contains radiation-absorbing surfaces.

18. The detector as defined in claim 16, wherein the diaphragm means comprise lamellae.

19. The detector as defined in claim 16, wherein the diaphragm means is essentially honeycomb-shaped.

20. The detector as defined in claim 16, wherein the diaphragm means comprise bores provided in a good thermally-conductive solid body member.

21. The detector as defined in claim 13, further including an additional filter with equivalent properties as said filter arranged at the front of the detector, said additional filter being arranged in front of the radiation receiver.

22. The detector as defined in claim 1, wherein the intersection locations of the receiving regions are disposed behind the radiation receiver.

23. The detector as defined in claim 1, wherein the intersection location of the receiving regions are located behind the reflector surfaces.

24. An infrared radiation-burglary detector comprising a common radiation receiver for different receiving regions, a number of reflector surfaces focusing the radiation arriving from the different receiving regions upon the common radiation receiver, said reflector surfaces being arranged and aligned such that all real and virtual intersection locations of the receiving regions, viewed in the irradiation direction are located behind the front of the detector, in order to thereby prevent focusing of radiation upon said common radiation receiver from an object disposed at any location in front of the detector by more than one of said reflector surfaces.