Object sensor and a windshield wiper controller using the same

• US 6,590,662 B2
• Filed: 12/26/2000
• Issued: 07/08/2003
• Est. Priority Date: 12/28/1999
• Status: Expired due to Fees

• Current Assignee: Niles Company Limited (Valeo SE)
• Original Assignee: Nippon Sheet Glass Company Limited
• Inventors: Kokuryo, Kazuto, Nagao, Shinji
• Primary Examiner(s): Rosenberger, Richard A.
• Assistant Examiner(s): Barth, Vincent P
• Application Number:
  US09/748,434
• Publication Number:
  US 20010012106A1
• Time in Patent Office: 924 Days
• Field of Search: 356/445, 250/214.R, 250/214.C, 250/214.1, 250/215, 250/573, 250/574, 318/483, 340/602, 327/514
• US Class Current: 356/445
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• CPC Class Codes: B60S 1/0833 Optical rain sensor
• CPC Class Codes: G01N 21/552 Attenuated total reflection

Abstract

An object sensor and object sensing method that sense the status of the sensing surface by detecting a dynamic impact of a rain drop, not by comparing the signal with a reference value. An object sensor sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprises: a means for generating a time lag signal from the output signal of the photo detector; a means for calculating a differential signal between the output signal of the photo detector and the time lag signal; and a means for judging the status of the sensing surface by detecting the generation of the differential signal.

Claims

1. An object sensor sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprising:

a means for generating a time lag signal from the output signal of the photo detector;

a means for calculating a differential signal between the output signal of the photo detector and the time lag signal; and

a means for judging the status of the sensing surface by detecting the generation of the differential signal.

2. The object sensor according to claim 1, wherein said means for canceling the noise and/or said means for generating a time lag signal are/is an analog circuit for generating the time lag signal.

3. The object sensor according to claim 1, further comprising an A/D conversion means for converting an analog signal to a digital signal by sampling the analog signal of the photo detector over a predetermined period;

wherein said means for canceling the noise and/or said means for generating a time lag signal are/is a means for leveling the predetermined number of the sampled signal inputted sequentially from the A/D conversion means.

4. The object sensor according to claim 1, wherein said object to be sensed is an impact of a water drop on the sensing surface.

5. The object sensor according to claim 1, wherein said object to be sensed is an impact of a water drop on the sensing surface, and when the differential signal is calculated as a value by subtracting the signal of the photo detector or the signal of the noise-cancelled signal from the time lag signal, the impact of a water drop on the sensing surface is sensed when a positive differential signal is generated.

6. The object sensor according to claim 5, wherein said object to be sensed is an impact of a rain drop on the sensing surface.

7. The object sensor according to claim 6, wherein the size of the water drop impacting the sensing surface is judged by the value of the differential signal.

8. The object sensor according to claim 1, the spike noise is cancelled from the signal of the photo detector.

9. A windshield wiper control system that controls a windshield wiper by the signal outputted from the object sensor claimed in claim 1.

10. An object sensor sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprising:

a means for canceling a noise in a signal outputted from a photo detector;

a means for generating a time lag signal from the noise-cancelled signal;

a means for calculating a differential signal between the noise-cancelled signal and the time lag signal; and

a means for judging the status of the sensing surface by detecting the generation of the differential signal.

11. The object sensor according to claim 10, wherein said means for canceling the noise and/or said means for generating a time lag signal are/is an analog circuit for generating the time lag signal.

12. The object sensor according to claim 10, further comprising an A/D conversion means for converting an analog signal to a digital signal by sampling the analog signal of the photo detector over a predetermined period;

wherein said means for canceling the noise and/or said means for generating a time lag signal are/is a means for leveling the predetermined number of the sampled signal inputted sequentially from the A/D conversion means.

13. The object sensor according to claim 10, wherein said object to be sensed is an impact of a water drop on the sensing surface.

14. The object sensor according to claim 10, wherein said object to be sensed is an impact of a water drop on the sensing surface, and when the differential signal is calculated as a value by subtracting the signal of the photo detector or the signal of the noise-cancelled signal from the time lag signal, the impact of a water drop on the sensing surface is sensed when a positive differential signal is generated.

15. The object sensor according to claim 14, wherein said object to be sensed is an impact of a rain drop on the sensing surface.

16. The object sensor according to claim 15, wherein the size of the water drop impacting the sensing surface is judged by the value of the differential signal.

17. The object sensor according to claim 10, the spike noise is cancelled from the signal of the photo detector.

18. A windshield wiper control system that controls a windshield wiper by the signal outputted from the object sensor claimed in claim 10.

19. An object sensor sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprising:

a means for generating a first order time lag signal from the output signal of the photo detector;

a means for generating a second order time lag signal from the first order time lag signal;

a means for calculating a differential signal between the first order time lag signal and the second order time lag signal; and

a means for judging the status of the sensing surface by detecting the generation of the differential signal.

20. The object sensor according to of claim 19, wherein said means for canceling the noise and/or said means for generating a time lag signal are/is an analog circuit for generating the time lag signal.

21. The object sensor according to claim 19, further comprising an A/D conversion means for converting an analog signal to a digital signal by sampling the analog signal of the photo detector over a predetermined period;

wherein said means for canceling the noise and/or said means for generating a time lag signal are/is a means for leveling the predetermined number of the sampled signal inputted sequentially from the A/D conversion means.

22. The object sensor according to claim 19, wherein said object to be sensed is an impact of a water drop on the sensing surface.

23. The object sensor according to claim 19, wherein said object to be sensed is an impact of a water drop on the sensing surface, and when the differential signal is calculated as a value by subtracting the first order time lag signal from the second order time lag signal, the impact of a water drop on the sensing surface is sensed when a positive differential signal is generated.

24. The object sensor according to claim 23, wherein said object to be sensed is an impact of a rain drop on the sensing surface.

25. The object sensor according to claim 24, wherein the size of the water drop impacting the sensing surface is judged by the value of the differential signal.

26. The object sensor according to claim 19, the spike noise is cancelled from the signal of the photo detector.

27. A windshield wiper control system for controlling a windshield wiper by the signal outputted from the object sensor claimed in claim 19.

28. An object sensor sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprising:

a circuit element for generating a time lag signal from the output signal of the photo detector;

a circuit element for calculating a differential signal between the output signal of the photo detector and the time lag signal; and

a circuit element for judging the status of the sensing surface by detecting the generation of the differential signal.

29. The object sensor according to claim 28, wherein said circuit element for canceling the noise and/or said circuit element for generating a time lag signal are/is an analog circuit for generating the time lag signal.

30. The object sensor according to claim 28, further comprising an A/D conversion circuit element for converting an analog signal to a digital signal by sampling the analog signal of the photo detector over a predetermined period;

wherein said circuit element for canceling the noise and/or said circuit element for generating a time lag signal are/is a circuit element for leveling the predetermined number of the sampled signal inputted sequentially from the A/D conversion circuit element.

31. The object sensor according to claim 28, wherein said object to be sensed is an impact of a water drop on the sensing surface.

32. The object sensor according to claim 28, wherein said object to be sensed is an impact of a water drop on the sensing surface, and when the differential signal is calculated as a value by subtracting the signal of the photo detector or the signal of the noise-cancelled signal from the time lag signal, the impact of a water drop on the sensing surface is sensed when a positive differential signal is generated.

33. The object sensor according to claim 32, wherein said object to be sensed is an impact of a rain drop on the sensing surface.

34. The object sensor according to claim 33, wherein the size of the water drop impacting the sensing surface is judged by the value of the differential signal.

35. The object sensor according to claim 28, the spike noise is cancelled from the signal of the photo detector.

36. A windshield wiper control system that controls a windshield wiper by the signal outputted from the object sensor claimed in claim 28.

37. An object sensor sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprising:

a circuit element for canceling a noise in a signal which is outputted from a photo detector;

a circuit element for generating a time lag signal from the noise-cancelled signal;

a circuit element for calculating a differential signal between the noise-cancelled signal and the time lag signal; and

a circuit element for judging the status of the sensing surface by detecting the generation of the differential signal.

38. The object sensor according to claim 37, wherein said circuit element for canceling the noise and/or said circuit element for generating a time lag signal are/is an analog circuit for generating the time lag signal.

39. The object sensor according to claim 37, further comprising an A/D conversion circuit element for converting an analog signal to a digital signal by sampling the analog signal of the photo detector over a predetermined period;

wherein said circuit element for canceling the noise and/or said circuit element for generating a time lag signal are/is a circuit element for leveling the predetermined number of the sampled signal inputted sequentially from the A/D conversion circuit element.

40. The object sensor according to claim 37, wherein said object to be sensed is an impact of a water drop on the sensing surface.

41. The object sensor according to claim 37, wherein said object to be sensed is an impact of a water drop on the sensing surface, and when the differential signal is calculated as a value by subtracting the signal of the photo detector or the signal of the noise-cancelled signal from the time lag signal, the impact of a water drop on the sensing surface is sensed when a positive differential signal is generated.

42. The object sensor according to claim 40, wherein said object to be sensed is an impact of a rain drop on the sensing surface.

43. The object sensor according to claim 41, wherein the size of the water drop impacting the sensing surface is judged by the value of the differential signal.

44. The object sensor according to claim 37, the spike noise is cancelled from the signal of the photo detector.

45. A windshield wiper control system that controls a windshield wiper by the signal outputted from the object sensor claimed in claim 37.

46. An object sensor sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprising:

a circuit element for generating a first order time lag signal from the output signal of the photo detector;

a circuit element for generating a second order time lag signal from the first order time lag signal;

a circuit element for calculating a differential signal between the first order time lag signal and the second order time lag signal; and

a circuit element for judging the status of the sensing surface by detecting the generation of the differential signal.

47. The object sensor according to claim 46, wherein said circuit element for canceling the noise and/or said circuit element for generating a time lag signal are/is an analog circuit for generating the time lag signal.

48. The object sensor according to claim 46, further comprising an A/D conversion circuit element for converting an analog signal to a digital signal by sampling the analog signal of the photo detector over a predetermined period;

wherein said circuit element for canceling the noise and/or said circuit element for generating a time lag signal are/is a circuit element for leveling the predetermined number of the sampled signal inputted sequentially from the A/D conversion circuit element.

49. The object sensor according to claim 46, wherein said object to be sensed is an impact of a water drop on the sensing surface.

50. The object sensor according to claim 46, wherein said object to be sensed is an impact of a water drop on the sensing surface, and when the differential signal is calculated as a value by subtracting the first order time lag signal from the second order time lag signal, the impact of a water drop on the sensing surface is sensed when a positive differential signal is generated.

51. The object sensor according to claim 50, wherein said object to be sensed is an impact of a rain drop on the sensing surface.

52. The object sensor according to claim 51, wherein the size of the water drop impacting the sensing surface is judged by the value of the differential signal.

53. The object sensor according to claim 46, the spike noise is cancelled from the signal of the photo detector.

54. A windshield wiper control system that controls a windshield wiper by the signal outputted from the object sensor claimed in claim 46.

55. An object sensing method for sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprising:

generating a time lag signal from the output signal of the photo detector;

calculating a differential signal between the output signal of the photo detector and the time lag signal; and

judging the status of the sensing surface by detecting the generation of the differential signal.

56. A windshield wiper control method comprising controlling a windshield wiper with the detection of differential signal claimed in claim 55.

57. An object sensing method for sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprising:

canceling a noise in a signal which is outputted from a photo detector;

generating a time lag signal from the noise-cancelled signal;

calculating a differential signal between the noise-cancelled signal and the time lag signal; and

judging the status of the sensing surface by detecting the generation of the differential signal.

58. A windshield wiper control method comprising controlling a windshield wiper with the detection of differential signal claimed in claim 57.

59. An object sensing method for sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface comprising:

generating a first order time lag signal from the output signal of the photo detector;

generating a second order time lag signal from the first order time lag signal;

calculating a differential signal between the first order time lag signal and the second order time lag signal; and

judging the status of the sensing surface by detecting the generation of the differential signal.

60. A windshield wiper control method comprising controlling a windshield wiper with the detection of differential signal claimed in claim 59.