Passive infra-red detectors

• US 7,504,633 B2
• Filed: 06/22/2006
• Issued: 03/17/2009
• Est. Priority Date: 03/21/2005
• Status: Active Grant

• Current Assignee: Tyco Fire & Security GmbH (Johnson Controls International plc)
• Original Assignee: Visonic Incorporated (Johnson Controls International plc)
• Inventors: Zhevelev, Boris, Kotlicki, Yaacov, Lahat, Michael
• Primary Examiner(s): Porta; David P
• Assistant Examiner(s): Malevic; Djura
• Application Number:
  US11/425,770
• Publication Number:
  US 20070145277A1
• Time in Patent Office: 999 Days
• Field of Search: 250/353
• US Class Current: 250/353
• CPC Class Codes: G01J 5/0025 Living bodies ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00
• CPC Class Codes: G01J 5/026 Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• CPC Class Codes: G01J 5/07 Arrangements for adjusting the solid angle of collected radiation, e.g. adjusting or orienting field of view, tracking position or encoding angular position optical collimating elements G01J5/0806
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0802 Optical filters
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors
• CPC Class Codes: G01J 5/0846 having multiple detectors for performing different types of detection, e.g. using radiometry and reflectometry channels
• CPC Class Codes: G08B 13/193 using focusing means
• CPC Class Codes: G08B 29/18 Prevention or correction of operating errors G08B29/02, G08B29/12 take precedence
• CPC Class Codes: Y10S 250/01 Passive intrusion detectors

Abstract

A passive infra-red detector including at least three sub-detectors, each sub-detector being operative to receive infra-red radiation from a corresponding one of at least three sub fields-of-view, each sub field-of-view being exclusively defined by an optical element which does not define any other sub field of view, the sub fields-of-view being angled with respect to each other, adjacent ones of the sub fields-of-view being separated by a gap of no more than 30 degrees and at least one of the sub fields-of-view having at least one of the following characteristics: extending over no more then 45 degrees in azimuth; and including not more than three azimuthally distributed detection zones, and signal processing circuitry, operative to receive output signals from the sub detectors and to provide a motion detection output.

Claims

1. A radiation detector comprising:

a housing defining an elongate radiation receiving slit aperture lying along a slit axis;

a radiation sensor disposed within said housing along said slit axis at a location spaced from said elongate radiation receiving slit aperture; and

a radiation reflecting surface arranged to receive radiation passing through said elongate radiation receiving slit aperture and to focus said radiation on said radiation sensor, said radiation reflecting surface being defined at least partially by rotation through a rotation angle about said slit axis of a portion of a parabola, whose axis of symmetry extends perpendicularly to said slit axis through said radiation sensor.

2. A radiation detector according to claim 1 and wherein said rotation angle is 90 degrees.

3. A radiation detector according to claim 1 and being operative such that when said slit axis is a horizontal axis, said rotation angle defines the angular extent of a radiation receiving curtain in a vertical plane.

4. A radiation detector according to claim 1 and also comprising at least one intermediate reflecting surface located along an optical path defined by said radiation reflecting surface at a location suitable for redirecting radiation from said radiation reflecting surface to said radiation sensor.

5. A radiation detector according to claim 1 and also comprising a window transparent to infra-red radiation, located adjacent said radiation receiving slit aperture.

6. A radiation detector according to claim 5 and wherein a center of said window is located generally at a center of said radiation receiving slit aperture.

7. A radiation detector according to claim 6 and wherein said window does not have optical power and does have varying thickness, thereby providing varying radiation attenuation.

8. A radiation detector according to claim 7 and wherein said varying radiation attenuation provides pet immunity.

9. A radiation detector according to claim 5 and wherein said window has a circular cross-section.

10. A radiation detector according to claim 5 and wherein said window is generally flat.

11. A radiation detector according to claim 5 and wherein said window is formed of at least one of HDPE, Silicon and Germanium.

12. A radiation detector according to claim 1 and wherein said radiation reflecting surface includes a plurality of reflecting surface areas corresponding to a plurality of radiation receiving areas, wherein different ones of said plurality of reflecting surface areas have different widths, thereby providing different sensitivity of said radiation sensor at corresponding ones of said plurality of radiation receiving areas.

13. A radiation detector according to claim 12 and wherein said different sensitivity of said radiation sensor at corresponding ones of said plurality of radiation receiving areas provides pet immunity.

14. A radiation detector according to claim 1 and wherein said radiation sensor is operative to view a field-of-view comprising a curtain-like field-of-view.

15. A radiation detector according to claim 14 and wherein said curtain-like field-of-view extends generally through 90 degrees.

16. A radiation detector according to claim 15 and wherein said curtain-like field-of-view extends generally through 90 degrees from the vertical to the horizontal.

17. A radiation detector comprising:

a housing defining an elongate radiation receiving slit aperture lying along a slit axis;

a radiation sensor disposed within said housing at a location spaced from said elongate radiation receiving slit aperture; and

a radiation reflecting surface arranged to receive radiation passing through said elongate radiation receiving slit aperture and to focus said radiation on said radiation sensor, said radiation reflecting surface being defined at least partially by rotation through a rotation angle about said slit axis of a portion of a parabola, whose axis of symmetry extends perpendicularly to said slit axis.

18. A radiation detector according to claim 17 and wherein said rotation angle is 90 degrees.

19. A radiation detector according to claim 17 and being operative such that when said slit axis is a horizontal axis, said rotation angle defines the angular extent of a radiation receiving curtain in a vertical plane.

20. A radiation detector according to claim 17 and also comprising at least one intermediate reflecting surface located along an optical path defined by said radiation reflecting surface at a location suitable for redirecting radiation from said radiation reflecting surface to said radiation sensor.

21. A radiation detector according to claim 17 and also comprising a window transparent to infra-red radiation, located adjacent said radiation receiving slit aperture.

22. A radiation detector according to claim 21 and wherein a center of said window is located generally at a center of said radiation receiving slit aperture.

23. A radiation detector according to claim 22 and wherein said window does not have optical power and does have varying thickness, thereby providing varying radiation attenuation.

24. A radiation detector according to claim 23 and wherein said varying radiation attenuation provides pet immunity.

25. A radiation detector according to claim 21 and wherein said window has a circular cross-section.

26. A radiation detector according to claim 21 and wherein said window is generally flat.

27. A radiation detector according to claim 21 and wherein said window is formed of at least one of HDPE, Silicon and Germanium.

28. A radiation detector according to claim 17 and wherein said radiation reflecting surface includes a plurality of reflecting surface areas corresponding to a plurality of radiation receiving areas, wherein different ones of said plurality of reflecting surface areas have different widths, thereby providing different sensitivity of said radiation sensor at corresponding ones of said plurality of radiation receiving areas.

29. A radiation detector according to claim 28 and wherein said different sensitivity of said radiation sensor at corresponding ones of said plurality of radiation receiving areas provides pet immunity.

30. A radiation detector according to claim 17 and wherein said radiation sensor is operative to view a field-of-view comprising a curtain-like field-of-view.

31. A radiation detector according to claim 30 and wherein said curtain-like field-of-view extends generally through 90 degrees.

32. A radiation detector according to claim 31 and wherein said curtain-like field-of-view extends generally through 90 degrees from the vertical to the horizontal.