Force determination employing sheet sensor and capacitive array

Patent metadata

Field	Value
Publication number	US-10048789-B2
Application number	US-201514727601-A
Country	US
Kind code	B2
Filing date	Jun 1, 2015
Priority date	Feb 12, 2014
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

A device configured to sense a touch on a surface of the device. The device includes a cover and a force-sensing structure disposed below the cover. The force-sensing structure may be positioned below a display and used in combination with other force-sensing elements to estimate the force of a touch on the cover of a device.

First claim

We claim:

1. An electronic device comprising:
a cover;
a strain-sensitive gasket disposed along a perimeter of the cover, the strain-sensitive gasket having a first force sensing range for sensing forces applied to the cover;
a display positioned below the cover;
a force-sensing structure disposed below the display, wherein the force-sensing structure comprises:
a first capacitive plate;
a second capacitive plate disposed below the first capacitive plate; and
a compressible element disposed between the first and second capacitive plates; and

a plate affixed to and supporting the force-sensing structures;
wherein the force-sensing structure has a second force sensing range for sensing forces applied to the cover, the second force sensing range begins at a first threshold that corresponds to a minimum force that can be detected by the force-sensing structure, the first force sensing range ends at a second threshold that corresponds to a maximum force that can be detected by the strain-sensitive gasket, and the first threshold is less than the second threshold.

2. The electronic device of claim 1 , further comprising:
sensing circuitry that is operatively coupled to the force-sensing structure, wherein the sensing circuitry is configured to estimate the force of a touch on the cover based on a change in capacitance between the first capacitive plate and the second capacitive plate.

3. The electronic device of claim 1 , wherein the force-sensing structure is separated from the display by a compliant layer including an air gap.

4. The electronic device of claim 1 , wherein the force-sensing structure is separated from the display by a compliant layer comprised of compressible foam.

5. The electronic device of claim 1 , wherein the force-sensing structure is separated from the display by a compliant layer comprised of an array of compliant pillars and an optically transparent fluid.

6. The electronic device of claim 1 , further comprising:
a housing having a bezel surrounding the cover; and
an oleophobic coating disposed over at least a portion of a gap between the cover and the bezel;
wherein the strain-sensitive gasket is disposed in the gap.

7. An electronic device comprising:
a housing;
a cover disposed within an opening of the housing;
a strain-sensitive gasket disposed between the cover and the housing along a perimeter of the cover, the strain-sensitive gasket having a first force sensing range; and
a force-sensing structure disposed below the cover, the force-sensing structure having a second force sensing range;
wherein the second force sensing range begins at a first threshold, the first force sensing range ends at a second threshold, and the first threshold is less than the second threshold.

8. The electronic device of claim 7 , further comprising a plate fixed relative to the housing and supporting the force-sensing structure.

9. The electronic device of claim 7 , wherein the strain-sensitive gasket comprises:
a gasket first capacitive plate;
a gasket second capacitive plate; and
a gasket compressible element disposed between the gasket first capacitive plate and the gasket second capacitive plate.

10. The electronic device of claim 7 , further comprising:
a display disposed between the cover and the force-sensing structure; and
a compressible layer comprising an air gap between the display and the force-sensing structure.

11. The electronic device of claim 10 , wherein:
the air gap of the compressible layer is configured to at least partially collapse in response to a force of a touch that exceeds the first threshold.

12. The electronic device of claim 7 , further comprising:
a display disposed between the cover and the force-sensing structure; and
a compressible layer between the display and the force-sensing structure, wherein
the compressible layer is configured to at least partially collapse in response to a force of a touch that exceeds the first threshold.

13. The electronic device of claim 7 , wherein the force-sensing structure comprises:
a first capacitive plate;
a second capacitive plate; and
a compressible element disposed between the first capacitive plate and the second capacitive plate.

14. The electronic device of claim 7 , wherein the force-sensing structure comprises a strain gauge.

15. An electronic device comprising:
a cover;
a capacitive sense layer comprising a strain-sensitive gasket positioned along a perimeter and below the cover, the strain-sensitive gasket having a first force sensing range;
a compressible layer below the capacitive sense layer; and
a force-sensing structure disposed below the compressible layer, wherein the force-sensing structure comprises:
a first capacitive plate;
a compressible element disposed on one side of the first capacitive plate; and
a second capacitive plate disposed on a side of the compressible element that is opposite the first capacitive plate;
wherein, the force-sensing structure has a second force sensing range, the second force sensing range begins at a first threshold, the first force sensing range ends at a second threshold, and the first threshold is less than the second threshold.

16. The electronic device of claim 15 , further comprising:
a plate positioned below the force-sensing structure and supporting the force-sensing structure.

17. The electronic device of claim 15 , wherein the compressible layer comprises an air gap.

18. The electronic device of claim 15 , further comprising:
a display positioned below the cover; and
a backlight positioned below the display, wherein the capacitive sense layer is disposed between the display and the backlight.

19. The electronic device of claim 15 , further comprising:
sensing circuitry is operatively coupled to the capacitive sense layer and the force-sensing structure, wherein the sensing circuitry is configured to estimate the force of a touch on the cover based on a change in mutual capacitance between the capacitive sense layer and the second capacitive plate of the force-sensing structure.

20. The electronic device of claim 19 , wherein the sensing circuitry is configured to:
obtain a first capacitance between the first capacitive plate and the second capacitive plate of the force-sensing structure;
obtain a second capacitance between the first capacitive plate and the capacitive sense layer; and
generate an estimate of a force of a touch on the cover using the first and second capacitances.

Assignees

• Apple Inc

Inventors

• Filiz Sinan
• Grunthaner Martin P
• Smith John Stephen
• Ogata Charley T
• Sauer Christian M
• Choi Shin John
• Butler Christopher J
• Martisauskas Steven J

Classifications

• G06F3/0412

  Digitisers structurally integrated in a display · CPC title

• G06F2203/04105

  Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position · CPC title

• G06F3/0416

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06F3/0414 Primary

  using force sensing means to determine a position · CPC title

• G06F3/044 Primary

  by capacitive means · CPC title