Pyroelectric intrusion detection in motor vehicles

• US 6,166,625 A
• Filed: 07/29/1997
• Issued: 12/26/2000
• Est. Priority Date: 09/26/1996
• Status: Expired due to Fees

• Current Assignee: Donnelly Corporation (Magna International Incorporated)
• Original Assignee: Donnelly Corporation (Magna International Incorporated)
• Inventors: Agrawal, Anoop, McCarthy, Kevin, Teowee, Gimtong
• Primary Examiner(s): TONG, NINA C
• Application Number:
  US08/901,929
• Time in Patent Office: 1,246 Days
• Field of Search: 340/425.5, 340/426, 340/430, 340/555, 340/556, 340/567, 340/573, 340/429, 340/541, 340/565, 340/942, 307/10.2, 307/10.3, 307/10.4, 307/10.5, 180/167, 180/169, 180/287, 250/342, 250/DIG. 1, 250/353, 250/338.3
• US Class Current: 340/426.26
• CPC Class Codes: B60R 2325/304 Boats
• CPC Class Codes: B60R 25/1004 Alarm systems characterised by the type of sensor, e.g. current sensing means using door lock sensors B60R25/1001

Abstract

Pyroelectric detector systems may be used in vehicles for security applications, such as intrusion detection and anti-theft alarms. The pyroelectric detectors are small in size, highly reliable and consume very low power. They can be physically and electrically integrated with other vehicle components, including rear-view mirror assemblies in automobiles, without incurring additional installation costs. They can also be easily integrated into aircraft cockpits.

Claims

1. A method of ensuring reliable thermal detection of the presence of a body having a thermal profile in a compartment of a parked motor vehicle comprising the steps of:

providing a thermal energy detection system including a pyroelectric detector, said pyroelectric detector having a first pyroelectric sensing element and a second pyroelectric sensing element, said first and second pyroelectric sensing elements arranged in opposed connection, said thermal energy detection system further comprising control circuitry responsive to electrical indicatives generated by said opposed first and second sensing elements;

mounting said thermal energy detection system either in a trunk compartment or an interior compartment of the vehicle;

monitoring a thermal profile of said trunk compartment or said interior compartment of the vehicle using said thermal energy detection system when the vehicle is parked and operating under vehicle battery power;

sensing a change in the thermal profile due to the presence of a moving human body having a temperature different than the thermal profile; and

generating a signal indicative of the change in the sensed thermal profile in the trunk compartment or the interior compartment,

wherein said thermal energy detection system is responsive to frequencies of change in sensed thermal profile in a restricted frequency range, thereby reducing the chance of a false alarm situation.

2. The method according to claim 1, wherein radiation incident on said pyroelectric detector is filtered to have a wavelength between approximately 8 and 14 microns.

3. The method according to claim 1, wherein said thermal energy detection system resolves movement of a body at about 37°

C. moving at a distance of within about 1 to 5 meters of said pyroelectric detector.

4. The method according to claim 1, wherein said thermal energy detection system resolves movement of a body at approximately 37°

C. moving at a frequency of approximately 5 Hz.

5. The method according to claim 1, wherein the sensing step senses with a sensitivity greater than approximately 10⁵ cm Hz/W.

6. The method according to claim 1, wherein the sensing step senses with a sensitivity greater than approximately 10⁶ cm Hz/W.

7. The method according to claim 1, wherein said thermal energy detection system has a power consumption of less than 1 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

8. The method according to claim 1, wherein said thermal energy detection system has a power consumption of less than 1 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

9. The method according to claim 1, wherein said thermal energy detection system has a power consumption of less than 0.02 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

10. The method according to claim 1, further comprising:

providing a lens, said lens positioned in front of said pyroelectric detector and focusing incident radiation onto said pyroelectric detector.

11. The method according to claim 10, wherein said lens comprises a material that transmits radiation in approximately the 8 to 14 micron wavelength range.

12. The method according to claim 11, wherein said lens blocks radiation having a wavelength of approximately 0.3 to 3 microns.

13. The method of claim 10, wherein said lens comprises a material comprising at least one of Ge, Si, ZnS, CdS and a polyolefin.

14. The method of claim 10, wherein said lens comprises a polyolefin material.

15. The method of claim 10, wherein said lens comprises a material including at least one of a polypropylene, a polyethylene and a polymethylpentene material, or a copolymer thereof.

16. The method of claim 10, wherein said lens comprises at least one of a fish eye lens, a diffractive optic lens, a wide angle lens and a Fresnel lens.

17. The method of claim 10, wherein said lens comprises a plastic lens.

18. The method of claim 1, wherein said thermal energy detection system consumes a current of less than approximately 5.0 mA when operating under vehicle battery power.

19. The method of claim 1, wherein said thermal energy detection system consumes a current of less than approximately 1.5 mA when operating under vehicle battery power.

20. The method of claim 1, wherein said interior compartment comprises a rear-seating area of the vehicle.

21. The method of claim 1, wherein said thermal energy detection system is provided as a module.

22. The method of claim 1, wherein said control circuitry comprises an application specific integrated circuit.

23. The method of claim 1, wherein said opposed pyroelectric sensing elements are arranged in a parallel opposed connection.

24. The method of claim 1, wherein said opposed pyroelectric sensing elements are arranged in a series opposed connection.

25. The method according to claim 1, wherein said restricted frequency range is between approximately 0.5 Hz and 10 Hz.

26. The method of claim 1, wherein said signal generating step will not generate a signal for changes in the sensed thermal profile that are less than approximately 0.5 Hz.

27. A method of ensuring reliable thermal detection of the presence of a body having a thermal profile in a compartment of a parked motor vehicle comprising the steps of;

providing a thermal energy detection system including a pyroelectric detector, said pyroelectric detector comprising a first pyroelectric sensing element and a second pyroelectric sensing element, said first and second pyroelectric sensing elements arranged in opposed connection, said thermal energy detection system further comprising control circuitry responsive to electrical indicatives generated by said opposed first and second sensing elements;

mounting said thermal energy detection system either in a trunk compartment or an interior compartment of the vehicle;

monitoring a thermal profile of said trunk compartment or said interior compartment of the vehicle using said thermal energy detection system when the vehicle is parked and operating under vehicle battery power;

sensing a change in the thermal profile due to the presence of a moving human body having a temperature different than the thermal profile; and

generating a signal indicative of the change in the sensed thermal profile in either the trunk compartment or the interior compartment,

wherein said thermal energy detection system resolves movement of a human body at approximately 37°

C. moving at a distance of approximately 1 to 5 meters of said pyroelectric detector,

whereby thermal radiation emitted by said moving human body incident on at least one of said first pyroelectric sensing element and said second pyroelectric sensing element generates an output of said thermal energy detection system indicative of presence of a human body in either the trunk compartment or the interior compartment.

28. The method according to claim 27, wherein said thermal energy detection system is responsive to frequencies of change in sensed thermal profile in a restricted frequency range.

29. The method according to claim 28, wherein said restricted frequency range is between approximately 0.5 Hz and 10 Hz.

30. The method according to claim 27, wherein radiation incident on said pyroelectric detector is filtered so as to having a wavelength approximately between 8 to 14 microns.

31. The method according to claim 27, wherein said thermal energy detection system resolves movement of a body at approximately 37°

C. moving at a frequency of approximately 5 Hz.

32. The method according to claim 27, wherein the sensing step senses with a sensitivity greater than approximately 10⁵ cm Hz/W.

33. The method according to claim 27, wherein the sensing step senses with a sensitivity greater than approximately 10⁶ cm Hz/W.

34. The method according to claim 27, wherein said thermal energy detection system has a power consumption of less than approximately 1 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

35. The method according to claim 27, wherein said thermal energy detection system has a power consumption of less than approximately 0.1 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

36. The method according to claim 27, wherein said thermal energy detection system has a power consumption of less than approximately 0.02 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

37. The method according to claim 27, further comprising:

providing a lens, said lens positioned in front of said pyroelectric detector and focusing incident radiation onto said pyroelectric detector.

38. The method according to claim 37, wherein said lens blocks radiation having a wavelength of approximately 0.3 to 3 microns.

39. The method of claim 37, wherein said lens comprises a polyolefin material.

40. The method of claim 37, wherein said lens comprises a material comprising at least one of a polypropylene, a polyethylene and a polymethylpentene material, or a copolymer thereof.

41. The method of claim 37, wherein said lens comprises at least one of a fish eye lens, a diffractive optic lens, a wide angle lens and a Fresnel lens.

42. The method of claim 37, wherein said lens comprises a plastic lens.

43. The method according to claim 37, wherein said lens comprises a material that transmits radiation with a wavelength between approximately 8 and 14 microns.

44. The method of claim 43, wherein said lens comprises a material comprising at least one of Ge, Si, ZnS, CdS and a polyolefin.

45. The method of claim 27, wherein said thermal energy detection system consumes a current of less than approximately 5.0 mA when operating under vehicle battery power.

46. The method of claim 27, wherein said thermal energy detection system consumes a current of less than approximately 1.5 mA when operating under vehicle battery power.

47. The method of claim 27, wherein said interior compartment comprises a rear-seating area of the vehicle.

48. The method of claim 27, wherein said thermal energy detection system is provided as a module.

49. The method of claim 27, wherein said control circuitry comprises an application specific integrated circuit.

50. The method of claim 27, wherein said opposed sensing elements are arranged in a parallel opposed connection.

51. The method of claim 27, wherein said opposed sensing elements are arranged in a series opposed connection.

52. The method of claim 27, wherein said signal generating step will not generate a signal for frequencies of change in sensed thermal profile that are less than approximately 0.5 Hz.

53. A method of ensuring reliable thermal detection of the presence of a body in a compartment of a parked motor vehicle comprising the steps of:

providing a thermal energy detection system including a pyroelectric detector, said pyroelectric detector comprising a first pyroelectric sensing element and a second pyroelectric sensing element, said first and second pyroelectric sensing elements arranged in opposed connection, said thermal energy detection system further comprising control circuitry responsive to electrical indicatives generated by said opposed first and second sensing elements;

mounting said thermal energy detection system either in a trunk compartment or an interior compartment of the vehicle;

monitoring a thermal profile of either said trunk compartment or said interior compartment of the vehicle using said thermal energy detection system when the vehicle is parked and operating under vehicle battery power;

sensing a change in the thermal profile due to the presence of a moving human body having a temperature different than the thermal profile; and

generating a signal indicative of the change in the sensed thermal profile in either the trunk compartment or the interior compartment,

wherein said opposed sensors are arranged in one of a parallel opposed connection and series opposed connection,

whereby thermal radiation emitted by said moving human body incident on at least one of said first pyroelectric sensing element and said second pyroelectric sensing element generates an output of said thermal energy detection system indicative of presence of a human body in either the trunk compartment or said interior compartment.

54. The method according to claim 53, wherein the radiation incident on said pyroelectric detector is filtered to have a wavelength of approximately 8 to 14 microns.

55. The method according to claim 53, wherein said thermal energy detection system resolves movement of a body at about 37°

C. moving at a distance of approximately 1 to 5 meters of said pyroelectric detector.

56. The method according to claim 53, wherein said thermal energy detection system resolves movement of a body at approximately 37°

C. moving at a frequency of approximately 5 Hz.

57. The method according to claim 53, wherein the sensing step senses with a sensitivity greater than approximately 10⁵ cm Hz/W.

58. The method according to claim 53, wherein the sensing step senses with a sensitivity greater than approximately 10⁶ cm Hz/W.

59. The method according to claim 53, wherein said thermal energy detection system has a power consumption of less than approximately 1 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

60. The method according to claim 53, wherein said thermal energy detection system has a power consumption of less than approximately 0.1 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

61. The method according to claim 53, wherein said thermal energy detection system has a power consumption of less than approximately 0.02 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

62. The method according to claim 53, further comprising:

providing a lens, said lens positioned in front of said pyroelectric detector and focusing incident radiation onto said pyroelectric detector.

63. The method according to claim 62, wherein said lens comprises a material that transmits radiation with a wavelength between approximately 8 and 14 microns.

64. The method according to claim 63, wherein said lens blocks radiation having a wavelength of approximately 0.3 to 3 microns.

65. The method of claim 63, wherein said lens comprises a material comprising at least one of Ge, Si, ZnS, CdS and a polyolefin.

66. The method of claim 62, wherein said lens comprises a polyolefin material.

67. The method of claim 62, wherein said lens comprises a material comprising at least one of a polypropylene, a polyethylene and a polymethylpentene material, or a copolymer thereof.

68. The method of claim 62, wherein said lens comprises at least one of a fish eye lens, a diffractive optic lens, a wide angle lens and a Fresnel lens.

69. The method of claim 62, wherein said lens comprises a plastic lens.

70. The method of claim 53, wherein said thermal energy detection system consumes a current of less than approximately 5.0 mA when operating under vehicle battery power.

71. The method of claim 53, wherein said thermal energy detection system consumes a current of less than approximately 1.5 mA when operating under vehicle battery power.

72. The method of claim 53, wherein said interior compartment comprises a rear-seating area of the vehicle.

73. The method of claim 53, wherein said thermal energy detection system is provided as a module.

74. The method of claim 53, wherein said control circuitry comprises an application specific integrated circuit.

75. The method of claim 53, wherein said opposed sensing elements are arranged in a parallel opposed connection.

76. The method of claim 53, wherein said opposed sensing elements are arranged in a series opposed connection.

77. The method of claim 53, wherein said signal generating step will not generate a signal for frequencies of change in sensed thermal profile that are less than approximately 0.5 Hz.

78. A method of ensuring reliable thermal detection of the presence of a body in a compartment of a parked motor vehicle comprising the steps of:

providing a thermal energy detection system including a pyroelectric detector, said pyroelectric detector comprising a first pyroelectric sensing element and a second pyroelectric sensing element, said first and second pyroelectric sensing elements arranged in opposed connection, said thermal energy detection system further comprising control circuitry responsive to electrical indicatives generated by said opposed first and second sensing elements;

mounting said thermal energy detection system either in a trunk compartment or an interior compartment of the vehicle;

monitoring a thermal profile of either said trunk compartment or said interior compartment of the vehicle using said thermal energy detection system when the vehicle is parked and operating under vehicle battery power;

sensing a change in the thermal profile due to the presence of a moving human body having a temperature different than the thermal profile; and

generating a signal indicative of the change in the sensed thermal profile in either the trunk compartment or the interior compartment;

wherein said thermal energy detection system consumes a current of less than 5.0 mA when operating under vehicle battery power,

whereby thermal radiation emitted by said moving human body incident on at least one of said first pyroelectric sensing element and said second pyroelectric sensing element generates an output of said thermal energy detection system indicative of presence of a human body in either the trunk compartment or said interior compartment.

79. The method according to claim 78, wherein the radiation incident on said pyroelectric detector is filtered to have a wavelength of approximately 8 to 14 microns.

80. The method according to claim 78, wherein said thermal energy detection system resolves movement of a body at about 37°

C. moving at a distance of approximately 1 to 5 meters of said pyroelectric detector.

81. The method according to claim 78, wherein said thermal energy detection system resolves movement of a body at approximately 37°

C. moving at a frequency of approximately 5 Hz.

82. The method according to claim 78, wherein the sensing step senses with a sensitivity greater than approximately 10⁵ cm Hz/W.

83. The method according to claim 78, wherein the sensing step senses with a sensitivity greater than approximately 10⁶ cm Hz/W.

84. The method according to claim 78, wherein said thermal energy detection system has a power consumption of less than approximately 1 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

85. The method according to claim 78, wherein said thermal energy detection system has a power consumption of less than approximately 0.1 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

86. The method according to claim 78, wherein said thermal energy detection system has a power consumption of less than approximately 0.02 Watt when connected to vehicle battery power and when the vehicle is in the parked state.

87. The method according to claim 78, further comprising:

providing a lens, said lens positioned in front of said pyroelectric detector and focusing incident radiation onto said pyroelectric detector.

88. The method according to claim 78, wherein said lens comprises a material that transmits radiation with a wavelength between approximately 8 and 14 microns.

89. The method according to claim 78 wherein said lens blocks radiation having a wavelength of approximately 0.3 to 3 microns.

90. The method of claim 78 wherein said lens comprises a material comprising at least one of Ge, Si, ZnS, CdS and a polyolefin.

91. The method of claim 78, wherein said lens comprises a polyolefin material.

92. The method of claim 78, wherein said lens comprises a material comprising at least one of a polypropylene, a polyethylene and a polymethylpentene material, or a copolymer thereof.

93. The method of claim 78, wherein said lens comprises at least one of a fish eye lens, a diffractive optic lens, a wide angle lens and a Fresnel lens.

94. The method of claim 78, wherein said thermal energy detection system consumes a current of less than approximately 1.5 mA when operating under vehicle battery power.

95. The method of claim 78, wherein said interior compartment comprises a rear-seating area of the vehicle.

96. The method of claim 78, wherein said thermal energy detection system is provided as a module.

97. The method of claim 78, wherein said lens comprises a plastic lens.

98. The method of claim 78, wherein said control circuitry comprises an application specific integrated circuit.

99. The method of claim 78, wherein said opposed sensing elements are arranged in a parallel opposed connection.

100. The method of claim 78, wherein said opposed sensing elements are arranged in a series opposed connection.

101. The method of claim 78, wherein said signal generating step will not generate a signal for frequencies of change in sensed thermal profile that are less than approximately 0.5 Hz.