PROXIMITY SWITCH ASSEMBLY AND ACTIVATION METHOD

• US 20130270896A1
• Filed: 04/11/2012
• Published: 10/17/2013
• Est. Priority Date: 04/11/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Buttolo, Pietro, Salter, Stuart C., Gardner, Cornel Lewis, Rankin, James Stewart, Majkowski, Matthew
• Granted Patent: US 9,660,644 B2
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 2217/94052 with evaluation of actuation pattern or sequence, e.g. tapping
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe

Abstract

A proximity switch assembly and method for detecting activation of a proximity switch assembly is provided. The assembly includes a plurality of proximity switches each having a proximity sensor providing a sense activation field and control circuitry processing the activation field of each proximity switch to sense activation. The control circuitry monitors the signal responsive to the activation field and determines a differential change in generated signal, and further generates an activation output when the differential signal exceeds a threshold. The control circuitry further distinguishes an activation from an exploration of the plurality of switches and may determine activation upon detection of a stable signal.

Claims

1. A method of activating a proximity switch comprising:

generating an activation field with a proximity sensor;

monitoring amplitude of a signal generated in response to the activation field;

determining a differential change in the generated signal; and

generating an activation output when the differential signal exceeds a threshold.

2. The method of claim 1, wherein the step of determining a differential change in the generated signal comprises determining a first value at a first threshold, determining a second value at a second threshold, and determining the differential change in the generated signal based on a difference between the first value and the second value.

3. The method of claim 2, wherein the second threshold comprises a signal threshold for determining activation of the switch.

4. The method of claim 2, wherein the second threshold comprises a peak value of the signal.

5. The method of claim 2, wherein the first value comprises a first time and the second value comprises a second time, wherein the differential change in the generated signal comprises the difference in time between the first time and the second time.

6. The method of claim 5, wherein the differential change in generated signal is compared to a predetermined time period, and wherein an activation output is generated when the differential signal exceeds the difference in time.

7. The method of claim 1, wherein a plurality of activation fields are generated for a plurality of proximity sensors, and wherein the largest amplitude signal associated with the plurality of activation fields is processed to determine activation of one of the proximity sensors.

8. The method of claim 7, wherein the method further processes the plurality of activation fields to determination exploration of the plurality of sensors.

9. The method of claim 1, wherein the proximity switch is installed on a vehicle for use by a passenger in the vehicle.

10. The method of claim 1, wherein the proximity switch comprises a capacitive switch comprising one or more capacitive sensors.

11. A proximity switch assembly comprising:

a plurality of proximity switches each comprising a proximity sensor providing a sense activation field; and

control circuitry processing the activation field of each proximity switch to sense activation, said control circuitry monitoring a signal responsive to the activation field, determining a differential change in the generated signal, and generating an activation output when the differential signal exceeds a threshold.

12. The switch assembly of claim 11, wherein the control circuitry determines a first value at a first threshold, determining a second value at a second threshold, and determines the differential change in the generated signal based on a difference between the first value and the second value.

13. The switch assembly of claim 12, wherein the second threshold comprises a signal threshold for determining activation of the switch.

14. The switch assembly of claim 12, wherein the second threshold comprises a peak value of the signal.

15. The switch assembly of claim 12, wherein the first value comprises a first time and the second value comprises a second time, wherein the differential change in the generated signal comprises the difference in time between the first time and the second time.

16. The switch assembly of claim 15, wherein the differential change in generated signal is compared to a predetermined time period, and wherein an activation output is generated when the differential signal exceeds the difference in time.

17. The switch assembly of claim 11, wherein a plurality of activation fields are generated for a plurality of proximity sensors, and wherein a largest amplitude signal associated with the plurality of activation fields is processed to determine activation of one of the proximity sensors.

18. The switch assembly of claim 17, wherein the method further processes the plurality of activation fields to determination exploration of the plurality of sensors.

19. The switch assembly of claim 11, wherein the plurality of proximity switches are installed in a vehicle for use by a passenger of the vehicle.

20. The switch assembly of claim 11, wherein the plurality of proximity switches comprises a plurality of capacitive switches each comprising one or more capacitive sensors.