Proximity switch assembly and activation method with exploration mode

• US 8,933,708 B2
• Filed: 04/11/2012
• Issued: 01/13/2015
• 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
• Primary Examiner(s): Vazquez, Arleen M
• Assistant Examiner(s): HAWKINS, DOMINIC E
• Application Number:
  US13/444,393
• Publication Number:
  US 20130271157A1
• Time in Patent Office: 1,007 Days
• Field of Search: 324/647, 324/667, 324686-688, 324/76.39, 324/76.41, 324/76.56, 324/76.79, 324/76.2, 324/520, 324/527, 324/340, 324/702, 345/169, 345/173, 340/58
• US Class Current: 324/647
• 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 selecting a proximity switch, said method comprising:

generating a plurality of activation fields with a plurality of proximity sensors;

monitoring signals indicative of the activation fields;

detecting sliding of an object relative to the sensors in an exploration mode which enables the user to explore the proximity sensors without activating the proximity switch;

detecting one sensor having a largest signal; and

generating an activation output when the monitored signal associated with the one sensor has a stable amplitude for a predetermined time in the exploration mode.

2. The method of claim 1, wherein the stable amplitude is detected at the maximum value of the signal.

3. The method of claim 1, wherein the stable amplitude is detected at a value below the maximum value.

4. The method of claim 1, wherein the predetermined time is at least 50 ms.

5. The method of claim 1, wherein the exploration mode is detected based on multiple signals indicative of an object sensed with multiple proximity sensors.

6. The method of claim 5, wherein the signals are generated at the same time and each comprise a change in sensor count associated with an activation field.

7. The method of claim 4 further comprising the step of preventing tapping activation of the switch in the exploration mode.

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

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

10. A method of selecting a proximity switch, said method comprising:

generating a plurality of activation fields with a plurality of proximity sensors;

monitoring signals indicative of the activation fields;

detecting sliding of a user'"'"'s finger based on multiple signals and entering an exploration mode which enables the user to explore the proximity sensors without activating the proximity switch;

preventing tapping activation of the switch in the exploration mode;

detecting one sensor having a largest signal; and

generating an activation output when the largest signal has a stable amplitude for a predetermined time while in the exploration mode.

11. The method of claim 10, wherein the stable amplitude is detected at the maximum value of the signal.

12. The method of claim 10, wherein the stable amplitude is detected a value below the maximum value.

13. The method of claim 10, wherein the stable amplitude is detected at a maximum value indicative of a press of an object on a sensor surface for a minimum time period.

14. The method of claim 10, wherein the proximity switch is installed on a vehicle for use by a passenger in the vehicle.

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

16. A proximity switch assembly comprising:

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

control circuitry processing the activation field of each proximity switch to sense activation, said control circuitry monitoring signals indicative of the activation fields, detecting sliding of an object relative to the switches in an exploration mode which enables the user to explore the proximity sensors without activating the proximity switch, detecting a largest signal associated with one switch, and generating an activation output when the maximum signal has a stable amplitude for a predetermined time in the exploration mode.

17. The proximity switch assembly of claim 16, wherein the control circuitry further prevents tapping activation of a switch in the activation mode.

18. The proximity switch assembly of claim 16, wherein the control circuitry enters the exploration mode based on multiple signals.

19. The proximity switch assembly of claim 16, wherein the plurality of proximity switches are installed on a vehicle for use by a passenger in the vehicle.

20. The proximity switch assembly of claim 16, wherein the proximity switches comprises capacitive switches comprising one or more capacitive sensors.