Optical particle detectors

• US 7,616,126 B2
• Filed: 07/18/2006
• Issued: 11/10/2009
• Est. Priority Date: 07/18/2006
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Kadwell, Brian J., Stirling, Christopher D.
• Primary Examiner(s): HOFSASS, JEFFERY A
• Application Number:
  US11/488,315
• Publication Number:
  US 20080018485A1
• Time in Patent Office: 1,211 Days
• Field of Search: 340/628, 340/629, 340/630
• US Class Current: 340/630
• CPC Class Codes: G08B 17/107 for detecting light-scattering due to smoke
• CPC Class Codes: G08B 17/113 Constructional details
• CPC Class Codes: G08B 3/10 using electric transmission; using electromagnetic transmission

Abstract

A particle sensor is provided that includes a light source, an optical transducer, and a controller, wherein the controller is in communication with the light source and the optical transducer. The controller is configured to reject substantially all signals except those contributed by the light source.

Claims

1. A particle sensor, comprising:

a light source, an optical transducer and a controller;

said controller in communication with said light source and said optical transducer, said controller is configured to reject substantially all signals except those contributed by said light source, wherein said controller is further configured to analyze a first output of said optical transducer taken at a first time while said light source is off.

2. A particle sensor as in claim 1 wherein said controller is further configured to analyze a second output of said optical transducer taken at a second time while said light source is on.

3. A particle sensor as in claim 2 wherein the particle sensor is configured to accept modulated power, said controller is further configured to delay said second output by a specific time delay.

4. A particle sensor as in claim 3 wherein said specific time delay is substantially a positive non-zero integer multiple of an input power source period.

5. A particle sensor as in claim 4 wherein said specific time delay is substantially equal to 1 period of an input power source.

6. A particle sensor as in claim 1 further comprising a chimney, an aesthetic cover, a circuit board, and a smoke cage at least partially defined by at least a portion of said chimney, at least a portion of said printed circuit board and at least a portion of said aesthetic cover.

7. A particle sensor as in claim 6 further comprising an alarm threshold.

8. A particle sensor as in claim 6 having a signal to noise ratio of 4:

1 or greater.

9. A particle sensor configured to be mounted to a substantially planar surface, comprising:

an aesthetic cover, a chimney and at least one additional component,

wherein at least a portion of said aesthetic cover, at least a portion of said chimney, and at least a portion of said at least one additional component at least partially defines a smoke cage, wherein airflow through said smoke cage flows substantially perpendicular to the substantially planar mounting surface; and

a light source, an optical transducer, and a controller in communication with said light source and said optical transducer, wherein the controller is configured to analyze a first output of said optical transducer taken at a first time while said light source is off.

10. A particle sensor as in claim 9 further comprising an alarm threshold.

11. A particle sensor as in claim 9 wherein said chimney comprises an optics block.

12. A particle sensor as in claim 11 wherein said chimney is constructed from a first portion and a second portion.

13. A particle sensor as in claim 12 wherein said first portion and second portion are configured to removably snap together.

14. A particle sensor as in claim 12 wherein said first portion and second portion are permanently attached to each other.

15. A particle sensor as in claim 9 wherein said smoke cage further comprises at least one finished surface.

16. A particle sensor as in claim 15 wherein said at least one finished surface comprises a low luster surface.

17. A particle sensor as in claim 16 wherein said at least one finished surface is substantially black.

18. A particle sensor as in claim 9 having an associated signal to noise ratio of 4:

1 or greater.

19. A particle sensor as in claim 18 having an associated signal to noise ratio of 5:

1 or greater.

20. A particle sensor as in claim 9 further configured such that a least sensitive particle sensor orientation with respect to airflow has an associated sensitivity of at least about 75%.

21. A particle sensor as in claim 9 further configured such that a least sensitive particle sensor orientation with respect to airflow has an associated sensitivity of at least about 90%.

22. A particle sensor as in claim 9 wherein said at least one additional component is a printed circuit board having an area configured to allow airflow therethrough.

23. A particle sensor as in claim 22 further comprising an alarm threshold.

24. A particle sensor as in claim 22 wherein said chimney comprises an optics block.

25. A particle sensor as in claim 24 wherein said chimney is constructed from a first portion and a second portion.

26. A particle sensor as in claim 25 wherein said first portion and second portion are configured to removably snap together.

27. A particle sensor as in claim 25 wherein said first portion and second portion are permanently attached to each other.

28. A particle sensor as in claim 22 wherein said smoke cage further comprises at least one finished surface.

29. A particle sensor as in claim 28 wherein said at least one finished surface comprises a low luster surface.

30. A particle sensor as in claim 29 wherein said at least one finished surface is substantially black.

31. A particle sensor as in claim 22 having an associated signal to noise ratio of 4:

1 or greater.

32. A particle sensor as in claim 31 having an associated signal to noise ratio of 5:

1 or greater.

33. A particle sensor as in claim 22 further configured such that a least sensitive particle sensor orientation with respect to airflow has an associated sensitivity of at least about 75%.

34. A particle sensor as in claim 22 further configured such that a least sensitive particle sensor orientation with respect to airflow has an associated sensitivity of at least about 90%.

35. A particle sensor as in claim 9, further comprising a light source wherein the primary optical axis of light emitted from said light source is substantially parallel to the planar mounting surface.

36. A particle sensor as in claim 35 further comprising an alarm threshold.

37. A particle sensor as in claim 35 wherein said chimney comprises an optics block.

38. A particle sensor as in claim 37 wherein said chimney is constructed from a first portion and a second portion.

39. A particle sensor as in claim 38 wherein said first portion and second portion are configured to removably snap together.

40. A particle sensor as in claim 38 wherein said first portion and second portion are permanently attached to each other.

41. A particle sensor as in claim 35 wherein said smoke cage further comprises at least one finished surface.

42. A particle sensor as in claim 41 wherein said at least one finished surface comprises a low luster surface.

43. A particle sensor as in claim 42 wherein said at least one finished surface is substantially black.

44. A particle sensor as in claim 35 having an associated signal to noise ratio of 4:

1 or greater.

45. A particle sensor as in claim 44 having an associated signal to noise ratio of 5:

1 or greater.

46. A particle sensor as in claim 35 further configured such that a least sensitive particle sensor orientation with respect to airflow has an associated sensitivity of at least about 75%.

47. A particle sensor as in claim 35 further configured such that a least sensitive particle sensor orientation with respect to airflow has an associated sensitivity of at least about 90%.

48. A particle sensor as in claim 9 wherein said aesthetic cover further comprises a removable portion at least partially covering said chimney, said removable portion configured to be removed in a single step.

49. A particle sensor as in claim 48 further comprising an alarm threshold.

50. A particle sensor as in claim 48 wherein said chimney comprises an optics block.

51. A particle sensor as in claim 50 wherein said chimney is constructed from a first portion and a second portion.

52. A particle sensor as in claim 51 wherein said first portion and second portion are configured to removably snap together.

53. A particle sensor as in claim 51 wherein said first portion and second portion are permanently attached to each other.

54. A particle sensor as in claim 48 wherein said smoke cage further comprises at least one finished surface.

55. A particle sensor as in claim 54 wherein said at least one finished surface comprises a low luster surface.

56. A particle sensor as in claim 55 wherein said at least one finished surface is substantially black.

57. A particle sensor as in claim 48 having an associated signal to noise ratio of 4:

1 or greater.

58. A particle sensor as in claim 57 having an associated signal to noise ratio of 5:

1 or greater.

59. A particle sensor as in claim 48 further configured such that a least sensitive particle sensor orientation with respect to airflow has an associated sensitivity of at least about 75%.

60. A particle sensor as in claim 48 further configured such that a least sensitive particle sensor orientation with respect to airflow has an associated sensitivity of at least about 90%.

67. A particle sensor as in claim 9 wherein said controller is further configured to analyze a second output of said optical transducer taken at a second time while said light source is on.

68. A particle sensor as in claim 67 wherein the particle sensor is configured to accept modulated power, said controller is further configured to delay said second output by a specific time delay.

69. A particle sensor as in claim 68 wherein said specific time delay is substantially a positive non-zero integer multiple of an input power source period.

70. A particle sensor as in claim 69 wherein said specific time delay is substantially equal to 1 period of an input power source.

71. A particle sensor as in claim 9 wherein said controller is further configured to reject substantially all signals except those contributed by said light source.

61. A particle sensor, comprising;

an aesthetic cover having a perimeter, a printed circuit board, a smoke cage, at least two thermal sensors, wherein said thermal sensors are positioned near the perimeter of the aesthetic cover and spaced about 120 degrees apart from each other, and a light source, an optical transducer, and a controller in communication with said light source and said optical transducer, wherein the controller is configured to analyze a first output of said optical transducer taken at a first time while said light source is off.

62. A particle sensor as in claim 61 wherein said aesthetic cover is configured to separate the thermal sensors from the area inside the aesthetic cover.

63. A particle sensor as in claim 61 further comprising an alarm threshold.

64. A particle sensor as in claim 63 having a signal to noise ratio of 4:

1 or greater.

65. A particle sensor as in claim 61 further comprising a chimney constructed from a first portion and a second portion.

66. A particle sensor as in claim 61 configured such that a least sensitive particle sensor orientation with respect to airflow has an associated sensitivity of at least about 75%.

72. A particle sensor as in claim 61 wherein said controller is further configured to analyze a second output of said optical transducer taken at a second time while said light source is on.

73. A particle sensor as in claim 72 wherein said specific time delay is substantially a positive non-zero integer multiple of an input power source period.

74. A particle sensor as in claim 73 wherein said specific time delay is substantially a positive non-zero integer multiple of an input power source period.

75. A particle sensor as in claim 74 wherein said specific time delay is substantially equal to 1 period of an input power source.

76. A particle sensor as in claim 61 wherein said controller is further configured to reject substantially all signals except those contributed by said light source.