Capacitive sensor

• US 9,886,119 B1
• Filed: 08/02/2016
• Issued: 02/06/2018
• Est. Priority Date: 08/02/2016
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Arola, Joni, Sasaki, Hiroshi
• Primary Examiner(s): Sharifi-Tafreshi, Koosha
• Application Number:
  US15/226,513
• Publication Number:
  US 20180039365A1
• Time in Patent Office: 553 Days
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A sensor and a method for detecting a displacement are disclosed with one implementation having a force sensor on a display. The sensor reacts to a bend of a conductor, wherein a diameter of the bends corresponds to a self-capacitance that is measurable from the conductor. In one embodiment the bent conductor is placed between two circuit boards or between a circuit board and a display, wherein a force applied to either surface causes a change in the bend diameter and the force may be measured. The sensor may be digital with a processor or analog with discrete components.

Claims

1. A sensor, comprising:

a conductor having a first end and a second end,

the conductor having a bend between the first end connectable to a first element and the second end connectable to a second element,

an electric voltage causing a self-capacitance in the conductor relative to a diameter of the bend, wherein the diameter of the bend corresponds a displacement of the second element in relation to the first element,

a signal source configured to generate an electric sensor signal, the electric sensor signal being applied to the conductor;

a signal receiver configured to measure a charge formed by the electric sensor signal from the conductor; and

a signal analyzer configured to detect a change in the charge formed by the electric sensor signal.

2. A sensor according to claim 1, comprising a processor and a memory storing instructions that, when executed, control operation of the sensor.

3. A sensor according to claim 1, wherein the signal source comprises a switching mode signal generator.

4. A sensor according to claim 1, wherein the signal receiver comprises a charge amplifier.

5. A sensor according to claim 1, wherein the electric sensor signal comprises a waveform.

6. A sensor according to claim 1, wherein the signal analyzer is configured to compare a capacitance formed by at least two sequences of the electric sensor signal to detect the change in the charge.

7. A sensor according to claim 1, wherein the conductor is configured on a flexible flat cable.

8. A sensor according to claim 1, wherein the conductor is configured on a flexible printed circuit.

9. A sensor according to claim 1, wherein the displacement of the second element is relative to a force applied on the second element and the signal analyzer is configured to transform the change in the charge formed by the electric sensor signal to a force applied on the second element.

10. A device, comprising:

a body,

a display,

a conductor having a first end connected to the body and a second end connected to the display,

the conductor having a bend between the first end and the second end,

an electric voltage causing a self-capacitance in the conductor relative to a diameter of the bend, wherein the diameter of the bend corresponds a displacement of the display in relation to the body,

a signal source configured to generate an electric sensor signal, the electric sensor signal being applied to the conductor;

a signal receiver configured to measure a charge formed by the electric sensor signal from the conductor; and

a signal analyzer configured to detect a change in the charge formed by the electric sensor signal.

11. A device according to claim 10, comprising a processor and a memory storing instructions that, when executed, control operation of the device.

12. A device according to claim 10, wherein the signal source comprises a switching mode signal generator.

13. A device according to claim 10, wherein the signal analyzer comprises a charge amplifier.

14. A device according to claim 10, wherein the signal analyzer is configured to compare a capacitance formed by at least two sequences of the electric sensor signal to detect the change in the charge.

15. A device according to claim 10, wherein the conductor is configured on a flexible flat cable or on a flexible printed circuit.

16. A device according to claim 10, wherein the first end of the conductor is connected to a portion of the body having a lower portion of the display and the second end of the conductor is connected to a top portion of the display.

17. A device according to claim 10, wherein the displacement of the display is relative to a force applied on the display and the signal analyzer is configured to transform the change in the charge formed by the electric sensor signal to a force applied on the display.

18. A method, comprising:

generating an electric sensor signal and applying it to a conductor having a first end, a second end, and a bend between the first end and the second end, wherein the bend is causing a distortion in the electric sensor signal and the distortion is relative to a diameter of the bend;

receiving the electric sensor signal from the conductor;

detecting the distortion from the electric sensor signal; and

analyzing the diameter of the bend.

19. A method according to claim 18, wherein the electric sensor signal comprises a square waveform.

20. A method according to claim 18, wherein analyzing the diameter of the bend comprises detecting a force applied on an element connected to the second end of the conductor.