Systems and methods for shielding a hand sensor system in a steering wheel

Patent metadata

Field	Value
Publication number	US-10124823-B2
Application number	US-201514719480-A
Country	US
Kind code	B2
Filing date	May 22, 2015
Priority date	May 22, 2014
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

Systems and methods of shielding a hand sensor system in a steering wheel are disclosed herein. An exemplary hand sensor system includes a sensor mat and a heater mat that is disposed between the sensor mat and a frame of the steering wheel. A power source selectively provides a heating current to the heater mat to provide heat to the steering wheel and a shielding voltage signal to the heater mat to provide electrical shielding for the sensor mat when heating is not needed or when sensing takes priority over heating. Alternatively, the system may include a shield mat that is separate from the heater mat and is disposed between the sensor mat and the heater mat. In addition, to isolate the signal carried by individual sensor return wires, a metallic or insulating covering or conduit may be provided around the wires or portions thereof.

First claim

The invention claimed is:

1. A system for shielding a hand sensor system in a steering wheel comprising:
a power source in communication with the hand sensor system;
a sensor mat comprising one or more capacitive sensing loops having respectively separate connections to the power source wherein each of the sensing loops receives, from the power source, a respective sensing voltage signal that defines a respective sensing zone in the sensor mat, and wherein the sensor mat transmits at least one presence signal from at least one of the sensor loops back to the power source to indicate a presence of an input in at least one of the sensing zones;
a heater mat disposed between a steering wheel frame and the sensor mat, the heater mat comprising one or more heating conductive loops connected to the power source, wherein the power source transmits a heating current to at least one of the heating conductive loops upon receiving the presence signal;
a shielding mat positioned between the heater mat and the sensor mat, the shielding mat comprising one or more shielding conductive loops having respectively separate connections to the power source wherein each of the shielding conductive loops receives a discrete shielding voltage signal from the power source, wherein the shielding conductive loops define respective shielding zones in the shielding mat,
wherein at least one of the sensing zones and at least one of the shielding zones occupy corresponding positions along the steering wheel, and the shielding zones shield the sensing zones from interference.

2. The system of claim 1 wherein the power source is further configured for generating the shielding voltage signal in response to receiving an override signal from another vehicle system in communication with the power source and indicating that sensing takes priority over heating.

3. The system of claim 1 , wherein the power source alternately generates the heating current and the shielding voltage signal periodically.

4. The system of claim 3 , wherein the power source is configured for alternately generating the heating current for about 10 to about 50 milliseconds and the shielding voltage signal for about 10 to about 50 milliseconds.

5. The system of claim 1 , wherein the heating current is between about 4 amperes and about 8 amperes.

6. The system of claim 1 , wherein the shielding voltage signal generates a shielding current on at least one of the shielding conductive loops that is less than about 200 microamperes.

7. The system of claim 1 , further comprising one or more sensor return wires extending out of the sensor mat and connecting the sensor loops to the power source and a metallic shield disposed around at least a portion of the sensor return wires, the metallic shield configured for substantially isolating the generated signal on the respective sensor return wires from another conductive element adjacent the sensor return wire.

8. The system of claim 7 , wherein:
the one or more sensing loops comprise a first sensing loop and a second sensing loop within the sensor mat;
a first sensor return wire extends out of the sensor mat and from the first sensing loop and a second sensor return wire extends out of the sensor mat and from the second sensing loop and a portion of the second sensor return wire crosses over the sensor mat and adjacent the first sensing loop; and
the metallic shield extends around at least the portion of the second sensor return wire that crosses over the first sensing loop.

9. The system of claim 8 , wherein the metallic shield extends around substantially all of the second sensor return wire that extends from the second sensing loop.

10. A system for shielding a hand sensor system in a steering wheel comprising:
an electronic control unit comprising a processor and a power source, wherein the electronic control unit accesses previously input shielding current values and heating current values for use by the processor in controlling the power source;
a sensor mat comprising one or more capacitive sensing loops connected to the electronic control unit with respectively separate sensor return wires and each of the sensing loops defining a sensing zone of the steering wheel upon receiving a sensing voltage signal from the power source;
a heater mat disposed between a steering wheel frame and the sensor mat, the heater mat comprising one or more heating conductive loops connected to the electronic control unit, wherein the processor instructs the power source to transmit a heating current, corresponding to the previously input heating current values, to at least one of the heating conductive loops upon receiving the presence signal; and
a shielding mat positioned between the heater mat and the sensor mat, the shielding mat comprising one or more shielding conductive loops connected to the electronic control unit by respectively separate conductive feed shielding wires, wherein the processor instructs the power source to transmit a shielding current, corresponding to the previously input shielding current values, to at least one of the shielding conductive loops such that the at least one of the shielding conductive loops defines a respective shielding zone in the shielding mat,
wherein the sensing zones and the shielding zones occupy corresponding positions along the steering wheel, and the shielding zones shield the sensing zones from interference.

11. The system of claim 10 , wherein the shielding electrical current is less than about 200 microamperes.

12. The system of claim 11 , wherein the shielding electrical current is about 10 microamperes.

13. The system of claim 10 , wherein the heating current generated is between about 4 amperes and about 8 amperes.

14. The system of claim 13 , wherein the heating current is about 7 amperes.

15. The system of claim 1 , wherein the power source is configured for generating the heating current for at least one of the one or more heating conductive loops of the heater mat in response to receiving an on signal for the heater mat.

16. The system of claim 1 , wherein the shielding mat is directly adjacent the sensor mat.

17. The system of claim 1 , further comprising an outer skin surrounding the sensor mat and under tension that squeezes the sensor mat and the shielding mat together.

18. The system of claim 1 , wherein respective sensor voltage signals and shielding voltage signals are substantially matching signals.

19. The system of claim 1 , wherein the electronic control unit is configured to generate the heating current for a selected heating conductive loop positioned adjacently a corresponding pair of a particular shielding conductive loop and a particular sensing loop when the particular sensing loop indicates that an input is sensed in the selected sensing zone.

20. A system for shielding a hand sensor system in a steering wheel comprising:
an electronic control unit comprising a power source and a processor accessing instructions in the electronic control unit, wherein the instructions allow the processor to determine an output from the power source;
a sensor mat comprising one or more capacitive sensing loops connected to the electronic control unit, wherein each of the sensing loops defines a respective sensing zone in the sensor mat, wherein each sensing loop is separately controlled by the power source;
a heater mat disposed between a steering wheel frame and the sensor mat, the heater mat comprising one or more heating conductive loops connected to the electronic control unit;
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Assignees

• Tk Holdings Inc
• Joyson Safety Systems Acquisition Llc

Inventors

• Van'Tzelfde Dwayne
• Maguire Phillip Bernard
• Mccurdy Justin Richard

Classifications

• B62D1/065

  Steering wheels with heating and ventilating means (heating and ventilation of steering wheel when connected to vehicle HVAC B60H1/00292) · CPC title

• H03K2217/960765

  Details of shielding arrangements · CPC title

• H03K17/962

  Capacitive touch switches · CPC title

• B62D1/06 Primary

  Rims, e.g. with heating means; Rim covers (B62D1/11 takes precedence) · CPC title

• H05K9/0071

  Active shielding · CPC title