Capacitive sensors in vehicular environments

• US 6,794,728 B1
• Filed: 08/24/2001
• Issued: 09/21/2004
• Est. Priority Date: 02/24/1999
• Status: Expired due to Term

• Current Assignee: Methode Electronics Incorporated
• Original Assignee: Advanced Safety Concepts, Inc.
• Inventors: Kithil, Philip W.
• Primary Examiner(s): NGUYEN, CUONG QUANG
• Application Number:
  US09/914,285
• Time in Patent Office: 1,124 Days
• Field of Search: 257/530-535
• US Class Current: 257/532
• CPC Class Codes: B60H 1/00742 by detection of the vehicle occupants' presence; by detection of conditions relating to the body of occupants, e.g. using radiant heat detectors
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60R 2021/01302 monitoring vehicle body vibrations or noise
• CPC Class Codes: B60R 21/013 including means for detecting collisions, impending collisions or roll-over
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558
• CPC Class Codes: B60R 21/0152 using strain gauges
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors

Abstract

Capacitive sensors used to detect force upon a transparency product for detecting and discriminating crash characteristics of a vehicle, as well as capacitive sensors used in conjunction with a conductive panel functioning as an airbag cover and ground plane for the capacitive sensors. The capacitive sensors are made up of electrodes, of which one may be a conductive coating. The capacitive sensors can be arranged upon a substrate and can include a reference sensor. Long term effects of temperature upon sensor output are compensated for with an algorithm comparing constant desired sensor output to low frequency drift due to temperature effects. Moisture upon a transparency product is distinguished from a nearby object due to the capacitance sensed. A sleep detection algorithm detects when a vehicle operator is drowsy. A capacitive sensor array having a nested circle sensor and L-shaped sensors, along with a dummy sensor is used in a sunroof-equipped vehicle for sensing occupant head position.

Claims

1. A force detecting capacitive sensor comprising a plurality of sets of at least two electrodes integral with a transparency product, said electrodes having mutual capacitance affected by force acting against the transparency product, wherein said plurality is configured for discriminating different vehicle crash characteristics.

2. The sensor of claim 1 wherein at least two of said at least two electrodes are parallel with one another.

3. The sensor of claim 1 wherein at least two of said at least two electrodes are non-parallel with one another.

4. The sensor of claim 1 wherein at least one of said at least two electrodes comprises a conductive coating integral with the transparency product.

5. The sensor of claim 1 further comprising a vehicle occupant protection system comprised of at least one occupant restraint device which operates in conjunction with said sensor.

6. The sensor of claim 1 wherein said sensor distinguishes between a visibility condition and an object in proximity to the transparency product based on said sensor response.

7. The sensor of claim 6 further comprising a vehicle occupant protection system that operates in conjunction with said sensor upon detecting an object in proximity to the transparency product.

8. The sensor of claim 6 further comprising means for initiating a response to modify a detected visibility condition.

9. A capacitive sensor comprising at least two electrodes integral with a transparency product, said electrodes having mutual capacitance affected by force acting against the transparency product, wherein said sensor distinguishes between a visibility condition and an object in proximity to the transparency product based on said sensor response.

10. The sensor of claim 9 further comprising a vehicle occupant protection system that operates in conjunction with said sensor upon detecting an object in proximity to the transparency product.

11. The sensor of claim 9 further comprising means for initiating a response to modify a detected visibility condition.

12. A method of employing a force detecting capacitive sensor, the method comprising the steps of:

employing a plurality of sets of at least two electrodes integral with a transparency product, the electrodes having mutual capacitance affected by force acting against the transparency product; and

configuring the plurality for discriminating different vehicle crash characteristics.

13. The method of claim 12 wherein in the employing step at least two of the at least two electrodes are parallel with one another.

14. The method of claim 12 wherein in the employing step at least two of the at least two electrodes are non-parallel with one another.

15. The method of claim 12 wherein in the employing step at least one of the at least two electrodes comprises a conductive coating integral with the transparency product.

16. The method of claim 15 further comprising the step of incorporating the sensor within a vehicle occupant protection system comprised of at least one occupant restraint device which operates in conjunction with the sensor.

17. The method of claim 12 additionally comprising the step of employing the sensor to distinguish between a visibility condition and an object in proximity to the transparency product based on the sensor response.

18. The method of claim 17 further comprising the step of incorporating the sensor within a vehicle occupant protection system that operates in conjunction with the sensor upon detecting an object in proximity to the transparency product.

19. The method of claim 17 further comprising the step of initiating a response to modify a detected visibility condition.

20. A method of employing a force detecting capacitive sensor, the method comprising the steps of:

employing at least two electrodes integral with a transparency product, the electrodes having mutual capacitance affected by force acting against the transparency product; and

distinguishing between a visibility condition and an object in proximity to the transparency product based on the sensor response.

21. The sensor of claim 20 further comprising the step of incorporating the sensor within a vehicle occupant protection system that operates in conjunction with the sensor upon detecting an object in proximity to the transparency product.

22. The sensor of claim 20 further comprising the step of initiating a response to modify a detected visibility condition.