Floating Plate Capacitive Sensor

• US 20110182458A1
• Filed: 01/28/2010
• Published: 07/28/2011
• Est. Priority Date: 01/28/2010
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Plantronics, Inc. (HP Inc.)
• Inventors: Lee, Barry J., Rosener, Douglas K.
• Granted Patent: US 9,479,857 B2
• Time in Patent Office: Days
• US Class Current: 381/384
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2217/96077 comprising an electrode which is floating
• CPC Class Codes: H04R 1/1041 Mechanical or electronic switches, or control elements switches in general H01H

Abstract

Methods and apparatuses for capacitive sensing are disclosed. In one example, a capacitive sensor includes a floating sense electrode disposed within proximity of an outward facing surface adapted to be brought in proximity to or touch a user skin surface. An interior electrode is disposed in proximity to the floating sense electrode, where the interior electrode and floating sense electrode form a capacitor.

Claims

1. A headset comprising:

a decoupled electrically conductive material disposed within proximity of a headset surface adapted to be brought in contact with a user ear, wherein a first capacitance is formed when the headset surface is brought in contact with the user ear;

a coupled electrically conductive material disposed in proximity to the decoupled electrically conductive material, the coupled electrically conductive material and decoupled electrically conductive material forming a capacitor having a second capacitance in series with the first capacitance; and

a processor coupled to the coupled electrically conductive material adapted to receive signals from the coupled electrically conductive material to determine a measured capacitance associated with the first capacitance and the second capacitance indicating a headset donned state or a headset doffed state.

2. The headset of claim 1, wherein the decoupled electrically conductive material is disposed at a headset earpiece.

3. The headset of claim 1, wherein the decoupled electrically conductive material is disposed at a spine portion of a headset housing.

4. The headset of claim 1, wherein the decoupled electrically conductive material is copper.

5. The headset of claim 1, wherein the measured capacitance is approximately the second capacitance when the headset is in a donned state.

6. The headset of claim 1, wherein the headset surface comprises an insulating material disposed over the decoupled electrically conductive material, the insulating material configured to contact the user ear when the headset is in a donned state.

7. The headset of claim 1, wherein the decoupled electrically conductive material is disposed on an outer headset surface, the decoupled electrically conductive material configured to contact the user ear when the headset is in a donned state.

8. A capacitive sensor comprising:

a decoupled sense electrode disposed within proximity of an outward facing surface adapted to be brought in proximity to or touch a user skin surface, wherein a first capacitance is formed when the decoupled sense electrode is brought in proximity to the user skin surface;

a coupled interior electrode disposed in proximity to the decoupled sense electrode, the coupled interior electrode and decoupled sense electrode forming a capacitor having a second capacitance; and

a sense circuit coupled to the coupled interior electrode, the sense circuit adapted to determine whether the decoupled sense electrode is in proximity to or touching the user skin surface.

9. The capacitive sensor of claim 8, wherein the sense circuit measures a capacitance approximately equal to the second capacitance when the decoupled sense electrode is touching the user skin surface.

10. The capacitive sensor of claim 8, wherein the outward facing surface comprises an insulating material disposed over the decoupled sense electrode, the insulating material configured to contact the user skin surface.

11. The capacitive sensor of claim 8, wherein the decoupled sense electrode is disposed on the outward facing surface, the decoupled sense electrode configured to contact the user skin surface.

12. The capacitive sensor of claim 8, wherein the decoupled sense electrode comprises an electrically conductive material.

13. The capacitive sensor of claim 8, wherein the sense circuit measures a capacitance dependent upon the first capacitance and the second capacitance.

14. A capacitive sensor comprising:

a decoupled electrically conductive material disposed within proximity of a surface adapted to be brought in proximity to or touch a user skin surface;

a coupled electrically conductive material, the coupled electrically conductive material and decoupled electrically conductive material forming a capacitor having an internal capacitance; and

a sense circuit coupled to the coupled electrically conductive material, the sense circuit adapted to determine whether the decoupled electrically conductive material is in proximity to or touching the user skin surface responsive to a measured capacitance determined by the internal capacitance and a sense capacitance between the user skin surface and the decoupled electrically conductive material.

15. The capacitive sensor of claim 14, wherein the sense circuit measures a capacitance approximately equal to the internal capacitance when the decoupled electrically conductive material is touching the user skin surface.

16. The capacitive sensor of claim 14, wherein the surface comprises an insulating material disposed over the decoupled electrically conductive material, the insulating material configured to contact the user skin surface.

17. The capacitive sensor of claim 14, wherein the decoupled electrically conductive material is disposed on an exterior face of the surface, the decoupled electrically conductive material configured to contact the user skin surface.

18. The capacitive sensor of claim 14, wherein the decoupled electrically conductive material is copper.

19. The capacitive sensor of claim 14, wherein the user skin surface is at a user finger brought in proximity to the capacitive sensor to indicate a user interface input action.

20. The capacitive sensor of claim 14, further comprising a printed circuit board, the sense circuit coupled to the printed circuit board, wherein the decoupled electrically conductive material is decoupled from the printed circuit board.

21. A capacitive sensor comprising:

a floating sense electrode disposed within proximity of an outward facing surface adapted to be brought in proximity to or touch a user skin surface; and

an interior electrode disposed in proximity to the floating sense electrode, wherein the interior electrode and the floating sense electrode form a capacitor having a capacitance, and the interior electrode is adapted to be directly coupled to a sense circuit configured to determine whether the floating sense electrode is in proximity to or touching the user skin surface.

22. The capacitive sensor of claim 21, wherein the floating sense electrode is an electrically conductive material deposited at a headset housing.

23. The capacitive sensor of claim 21, wherein the capacitance between the interior electrode and the floating sense electrode is measured when the floating sense electrode touches the user skin surface.

24. The capacitive sensor of claim 21, further comprising a second floating sense electrode disposed in proximity to the floating sense electrode.