Visibility sensor system

• US 5,982,288 A
• Filed: 04/01/1998
• Issued: 11/09/1999
• Est. Priority Date: 03/18/1997
• Status: Expired due to Fees

• Current Assignee: Sentech Incorporated (General Dynamics Corporation)
• Original Assignee: Sentech Incorporated (General Dynamics Corporation)
• Inventors: Sawatari, Takeo, Gaubis, Philip A., Charnetski, Clark J.
• Primary Examiner(s): Hofsass, Jeffery A.
• Assistant Examiner(s): TRIEU, VAN THANH
• Application Number:
  US09/053,034
• Time in Patent Office: 587 Days
• Field of Search: 340/601, 340/602, 340/604, 340/903, 340/905, 340/425.5, 318/483, 318/DIG. 2, 318/444, 250/338.1, 250/338.5, 250/339.1, 315/82, 315/156
• US Class Current: 340/601
• CPC Class Codes: B60Q 1/1423 Automatic dimming circuits, i.e. switching between high beam and low beam due to change of ambient light or light level in road traffic
• CPC Class Codes: G08G 1/096716 where the received information does not generate an automatic action on the vehicle control
• CPC Class Codes: G08G 1/096758 where no selection takes place on the transmitted or the received information
• CPC Class Codes: G08G 1/096775 where the origin of the information is a central station

Abstract

A visibility sensor system includes a housing having a sensor head opening. A removable sensor head assembly is removably coupled to the housing within the sensor head opening. The sensor head assembly has a sensor enclosure and a connector. An electronics module is coupled to the sensor head through the connector.

Claims

1. A visibility sensor assembly comprising:

a housing having a sensor head opening;

a removable sensor head assembly removably coupled to said housing within said sensor head opening, said sensor head assembly having a sensor enclosure and a connector wherein said sensor enclosure defines a first optical port and a second optical port each having a respective first hollow opening and a second hollow opening; and

an electronics module coupled to said sensor head through said connector.

2. A visibility sensor assembly as recited in claim 1, wherein said electronics module is coupled within said housing.

3. A visibility sensor assembly as recited in claim 1, wherein said removable sensor head assembly further comprises:

a first circuit board coupled to said sensor enclosure;

a first connector coupled to said first circuit board;

a light source coupled to said first circuit board, said first circuit board positioning said light source within said first optical port;

a second circuit board coupled to said sensor enclosure;

a second connector coupled to said second circuit board; and

a light detector coupled to said second circuit board, said second circuit board positioning said light detector within said second optical port.

4. A visibility sensor assembly as recited in claim 1, further comprising a first shutter for selectively closing said first hollow opening.

5. A visibility sensor assembly as recited in claim 1, further comprising a second shutter for selectively closing said second hollow opening.

6. A visibility sensor assembly as recited in claim 1, further comprising a heater positioned adjacent to said first hollow opening.

7. A visibility sensor assembly as recited in claim 1, wherein said housing includes a housing bottom surface and said sensor head assembly includes a sensor bottom surface flush with said housing bottom surface.

8. A visibility sensor assembly as recited in claim 1, further comprising a gasket sealing said sensor head opening.

9. A visibility sensor assembly as recited in claim 1, further comprising a magnet coupled within said housing.

10. A visibility sensor assembly as recited in claim 1, wherein said housing is an exterior mirror housing.

11. A visibility sensor assembly as recited in claim 1, further comprising a mechanical fastening device coupling said sensor head assembly to said housing.

12. A visibility sensor for an automotive vehicle comprising:

a housing having a sensor head opening;

a sensor head assembly including a mechanical fastening device configured to removably couple said assembly to said housing within said sensor head opening, said sensor head assembly further including a sensor enclosure having a first opening through which a light source in accordance with an input signal illuminates a sample volume outside said housing and a second opening through which a light detector detects light and generates an output signal indicative of the amount of light scattered from particles in the sample volume, said input signal and said output signal terminating in one or more connectors associated with said sensor head assembly;

means for selectively covering at least one of said first opening and said second opening;

an electronics module coupled to said sensor head assembly through said connector; and

a display electrically coupled to said sensor head assembly, said display coupled within the automotive vehicle.

13. A visibility sensor as recited in claim 12, wherein said electronics module is coupled within said housing.

14. A visibility sensor as recited in claim 12, wherein said electronics module is coupled within said automotive vehicle.

15. A visibility sensor as recited in claim 12 wherein said covering means includes a first shutter for selectively closing said first opening.

16. A visibility sensor as recited in claim 15 wherein said covering means further includes a second shutter for selectively closing said second opening.

17. A visibility sensor as recited in claim 12 further comprising a heater positioned adjacent to said first opening.

18. A visibility sensor as recited in claim 12, wherein said housing comprises an exterior rearview mirror housing.

19. A visibility sensor as recited in claim 12, further comprising one or more magnets coupled within said housing.

20. A visibility sensor as recited in claim 19, wherein said housing has a pair of legs, said magnets coupled to said legs.

21. A visibility sensor as recited in claim 12 wherein said covering means is responsive to a closure signal.

22. A visibility sensor as recited in claim 21 further including means for generating said closure signal as a function of at least temperature and humidity so as to open said covering means as the likelihood of fog increases.

23. A visibility sensor as recited in claim 22 wherein said closure signal generating means is further responsive to pressure.

24. A visibility sensor as recited in claim 21 further including means for generating said closure signal when a closure condition exists, said closure condition being one selected from the group consisting of a transmission of said automotive vehicle being in a neutral condition, the transmission being in a park condition, and an engine of said vehicle being in a stopped condition.

25. A visibility sensor as recited in claim 12 wherein said electronics module includes means for generating said input signal as a function of temperature and humidity so that said sample volume is illuminated at a rate corresponding to the likelihood of fog.

26. A visibility sensor as recited in claim 25 wherein said input signal generating means is further responsive to atmospheric pressure.

27. A sensor head assembly for a visibility sensor unit including a housing, said sensor head assembly comprising:

a sensor enclosure having a plurality of walls defining a first optical port and a second optical port, said first optical port having a first opening associated therewith and said second optical port having a second opening associated therewith;

a light source responsive to an input signal and disposed in said first optical port, said light source being configured to emit a light beam along a first optical axis through said first opening to illuminate a sample volume located outside of said head assembly;

means for selectively covering at least one of said first opening and said second opening;

a light detector disposed in said second optical port and configured to detect light through said second opening along a second optical axis and generate an output signal in response thereto indicative of the amount of light scattered from particles in the sample volume;

wherein said light source and said light detector are located at respective ends of said first and second optical ports distal from said first and second openings thereof to thereby minimize contamination of said light source and said light detector due to entry of contaminants through said first and second openings.

28. A sensor head assembly as recited in claim 27 wherein said covering means comprises a first shutter configured to selectively cover said first opening and a second shutter configured to selectively cover said second opening.

29. A sensor head assembly as recited in claim 28 wherein said first and second shutters are responsive to a closure signal generated as a function of at least temperature and humidity so as to open said first and second shutters at a rate increasing as the likelihood of fog increases.

30. A sensor head assembly as recited in claim 27 wherein said input signal and said output signal terminate in one or more connectors, said sensor head assembly further including a mechanical fastening device configured to removably secure said sensor head assembly to said housing.

31. A sensor head assembly as recited in claim 27 wherein said first and second optical ports comprise respective tubes.

32. A sensor head assembly as recited in claim 27 wherein said first optical axis and said second optical axis form an oblique angle therebetween.

33. A sensor head assembly as recited in claim 32 wherein said angle is about 150 degrees.