Proximity switch assembly and method therefor

• US 10,461,746 B2
• Filed: 03/20/2018
• Issued: 10/29/2019
• Est. Priority Date: 03/20/2018
• 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., Vemulapati, Satyanarayana Raju, Rankin, II, James Stewart
• Primary Examiner(s): Zhou, Hong
• Application Number:
  US15/926,228
• Publication Number:
  US 20190296738A1
• Time in Patent Office: 588 Days
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9455 constructional details of proximity switches using a magnetic detector H03K17/9505
• CPC Class Codes: H03K 2217/94026 Automatic threshold calibration; e.g. threshold automatically adapts to ambient conditions or follows variation of input
• CPC Class Codes: H03K 2217/945 Proximity switches
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches

Abstract

A proximity switch assembly is provided. The proximity switch assembly includes a proximity switch comprising a proximity sensor providing an activation field, and control circuitry monitoring a signal responsive to the activation signal and determining an activation of the switch, detecting a first peak value above a threshold when the signal is not stable followed by a drop and a subsequent rise to a second peak value followed by a sharp drop.

Claims

1. A proximity switch assembly comprising:

a proximity switch comprising a proximity sensor providing an activation field; and

control circuitry monitoring a signal responsive to the activation field and determining an activation of the switch based on detecting a first peak value above a threshold when the signal is not stable, followed by a drop and a subsequent rise to a second peak value followed by a sharp drop, wherein the control circuitry further delays recalibration of the switch assembly by a predetermined time period when the signal is detected dropping fast.

2. The switch assembly of claim 1, wherein the delay in recalibration is at least two seconds.

3. The switch assembly of claim 1, wherein the control circuitry further determines the signal drops below a baseline value.

4. The switch assembly of claim 1, wherein the drop from the first peak value exceeds a noise threshold.

5. The switch assembly of claim 4, wherein the drop from the first peak value exceeds at least twice the noise threshold.

6. The switch assembly of claim 1, wherein the proximity sensor comprises a sensor circuit formed on a flexible substrate.

7. The switch assembly of claim 1, wherein the proximity switch comprises a capacitive switch comprising a capacitive sensor.

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

9. A method of determining activation of a proximity switch comprising:

generating an activation field with a proximity sensor;

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

detecting a first peak value of the signal when the signal is not stable, followed by a drop in the signal, then a subsequent rise to a second peak value, followed by a sharp drop below a baseline value;

delaying recalibration of the switch by a fixed time when the signal drops below the baseline value; and

determining an activation of the switch based on the detecting step.

10. The switch assembly of claim 9, wherein the delay in recalibrating is at least two seconds.

11. The method of claim 9, wherein the drop from the first peak value exceeds a noise threshold.

12. The switch assembly of claim 11, wherein the drop from the first peak value exceeds at least twice the noise threshold.

13. The method of claim 9, wherein the proximity sensor comprises a sensor circuit formed on a flexible substrate.

14. The method of claim 9, wherein the proximity switch comprises a capacitive switch comprising a capacitive sensor.

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