PROXIMITY SWITCH HAVING DIFFERENTIAL CONTACT SURFACE

• US 20130271204A1
• 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: Salter, Stuart C., Buttolo, Pietro, Gardner, Cornel Lewis
• Granted Patent: US 9,197,206 B2
• Time in Patent Office: Days
• US Class Current: 327/517
• CPC Class Codes: H03K 17/94 characterised by the way in which the control signals are generated
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/975 using a capacitive movable element

Abstract

A proximity switch assembly and method for activating a proximity switch is provided. The assembly includes a proximity sensor generating a signal, and a contact surface proximate to the proximity sensor and having a differential elevation change feature. The proximity switch also includes control circuitry processing the signal to detect a differential increase in the activation signal indicative of a hard press on the contact surface. The control circuitry detects activation of the switch based on the differential increase exceeding a differential threshold. Activation can further be determined based on a stable signal.

Claims

1. A proximity switch comprising:

a proximity sensor generating a signal;

a contact surface proximate to the proximity sensor and comprising a differential elevation change feature; and

control circuitry processing the signal to detect a differential increase in the signal indicative of a hard press on the contact surface, wherein the control circuitry detects activation of the switch based on the differential increase exceeding a differential threshold.

2. The proximity switch of claim 1, wherein the control circuitry compares the signal to a threshold and actives the switch when the signal exceeds the threshold and the differential signal exceeds the differential threshold.

3. The proximity switch of claim 1, wherein the control circuitry further detects a substantially stable state of the signal following detection of the differential signal increase and activates the switch based on the presence of the substantially stable state and the differential signal exceeding the differential threshold.

4. The proximity switch of claim 3, wherein the substantially stable state comprises the signal being at a substantially constant value for a time period of at least 100 milliseconds.

5. The proximity switch of claim 1, wherein the differential elevation change feature comprises a recessed region in the contact surface.

6. The proximity switch of claim 5, wherein the recessed region comprises a ring-shaped trough.

7. The proximity switch of claim 1, wherein the differential elevation change feature comprises an elevated member extending from the contact surface.

8. The proximity switch of claim 7, wherein the elevated member comprises a ring-shaped member.

9. The proximity switch of claim 1 further comprising a backlight located proximate to the contact surface.

10. The proximity switch of claim 1, wherein the proximity sensor comprises a capacitive sensor.

11. The proximity switch of claim 1, wherein the proximity switch is employed on a vehicle.

12. A method of activating a proximity switch comprising:

providing a proximity sensor generating a signal;

providing a contact surface having a differential elevation change feature proximate to the proximity sensor;

processing the signal to detect a differential increase in the signal indicative of a hard press on the contact surface; and

detecting activation of the switch based on the differential increase exceeding a differential threshold.

13. The method of claim 12 further comprising the step of comparing the signal to a threshold and activating the switch when the signal exceeds the threshold and the differential signal exceeds the differential threshold.

14. The method of claim 12 further comprising the step of detecting a substantially stable state of the signal following detection of the differential signal increase and activating the switch based on the presence of the substantially stable state and the differential signal exceeding the differential threshold.

15. The method of claim 14, wherein the step of detecting a substantially stable state of the signal comprises detecting a substantially stable state of the signal at a substantially constant value for a time period of at least 100 milliseconds.

16. The method of claim 12, wherein the differential elevation change feature comprises a recessed region in the contact surface.

17. The method of claim 16, wherein the recessed region comprises a ring-shaped trough.

18. The method of claim 12, wherein the differential elevation change feature comprises an elevated member extending from a contact surface.

19. The method of claim 18, wherein the elevated member comprises a ring-shaped member.

20. The method of claim 12 further comprising the step of backlighting the contact surface.

21. The method of claim 12, wherein the proximity sensor comprises a capacitive sensor.

22. The method of claim 12, wherein the proximity switch is employed on a vehicle.