Embedded force measurement

• US 10,095,366 B2
• Filed: 07/21/2017
• Issued: 10/09/2018
• Est. Priority Date: 11/29/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Lynch, Stephen Brian, Rappoport, Benjamin Mark, Rothkopf, Fletcher R., Drzaic, Paul Stephen, Myers, Scott Andrew
• Primary Examiner(s): Sasinowski, Andrew
• Application Number:
  US15/656,983
• Publication Number:
  US 20170322653A1
• Time in Patent Office: 445 Days
• CPC Class Codes: G06F 1/1643 the display being associated to a digitizer, e.g. laptops that can be used as penpads details related to the relative motion of the display enclosure with respect to the body enclosure, e.g. to move between laptop and tablet PC configuration G06F1/1615
• CPC Class Codes: G06F 1/1652 the display being flexible, e.g. mimicking a sheet of paper, or rollable
• 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 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04144 using an array of force sensing means position sensing using the local deformation of sensor cells G06F3/0447
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

Disclosed embodiments relate to a force detection system that detects force exerted on a flexible display based upon changes in resistance and/or capacitance. In one embodiment, a method includes measuring a baseline comprising a baseline resistance or a baseline capacitance or both of a force measurement layer disposed within or overlaid on the display panel. The method further includes detecting a change in the baseline resistance or the baseline capacitance or both and calculating a change location where the change in the baseline resistance or the baseline capacitance or both occurred. The method also includes calculating a magnitude of the change in the baseline resistance or the baseline capacitance or both.

Claims

1. An electronic device, comprising:

a display;

a force measurement layer overlapping the display; and

processing circuitry configured to;

measure changes in a capacitance associated with a portion of the force measurement layer that occur in response to a touch input to the display;

in response to the changes in the capacitance of the force measurement layer, use the changes in the capacitance to determine a magnitude of force of the touch input; and

in response to the changes in the capacitance of the force measurement layer, use the changes in the capacitance to determine a location of the touch input.

2. The electronic device defined in claim 1, wherein the processing circuitry is further configured to provide a graphical output to the display that depends on the location and the magnitude of force of the touch input.

3. The electronic device defined in claim 1, wherein the processing circuitry is further configured to provide a graphical output to the display that depends on the magnitude of force of the touch input.

4. The electronic device defined in claim 1, wherein the processing circuitry is configured to measure a change from a baseline capacitance to a modified capacitance in response to the touch input.

5. The electronic device defined in claim 4, wherein the processing circuitry is further configured to provide a graphical output to the display that depends on a difference between the baseline capacitance and the modified capacitance.

6. The electronic device defined in claim 1, wherein the processing circuitry is further configured to:

provide a first graphical output to the display when the magnitude of force is equal to a first level of force; and

provide a second graphical output to the display when the magnitude of force is equal to a second level of force, wherein the first and second graphical outputs are different and wherein the first and second levels of force are different.

7. The electronic device defined in claim 6, wherein the processing circuitry is further configured to provide a third graphical output to the display when the magnitude of force is equal to a third level of force, wherein the first, second, and third graphical outputs are different, and wherein the first, second, and third levels of force are different.

8. The electronic device defined in claim 1, wherein the force measurement layer comprises at least one thin film plate.

9. The electronic device defined in claim 1, further comprising a cover layer that covers the display.

10. The electronic device defined in claim 9, wherein the cover layer has a first thickness in first portion of the cover layer and a second thickness that is different from the first thickness in a second portion of the cover layer.

11. An electronic device, comprising:

a housing;

a display coupled to the housing;

a force measurement layer overlapping the display, wherein a capacitance associated with the force measurement layer changes from a baseline capacitance to a modified capacitance in response to a touch input, wherein the touch input flexes the display relative to the housing, thereby changing the capacitance; and

processing circuitry configured to;

determine a difference between the baseline capacitance and the modified capacitance;

in response to determining the difference between the baseline capacitance and the modified capacitance, use the difference between the baseline capacitance and the modified capacitance to determine a magnitude of force of the touch input; and

provide a graphical output to the display that depends on the magnitude of force of the touch input.

12. The electronic device defined in claim 11, wherein the processing circuitry is further configured to use the difference between the baseline capacitance and the modified capacitance to determine a location of the touch input.

13. The electronic device defined in claim 12, wherein the graphical output provided to the display depends on the magnitude of force and the location of the touch input.

14. The electronic device defined in claim 11, further comprising a cover layer that covers the display.

15. An electronic device, comprising:

a display;

a force measurement layer that comprises an array of rows and columns of conductive structures, wherein the array overlays the display;

processing circuitry configured to;

measure a capacitance associated with the array, wherein the capacitance changes from a first capacitance to a second capacitance in response to a touch input on the display and wherein there is a difference between the first capacitance and the second capacitance; and

determine a magnitude of force of the touch input using the difference between the first capacitance and the second capacitance.

16. The electronic device defined in claim 15, wherein the processing circuitry is further configured to determine a location of the touch input using the difference between the first capacitance and the second capacitance.

17. The electronic device defined in claim 16, wherein the processing circuitry is further configured to provide a graphical output to the display that depends on the location and the magnitude of force of the touch input.

18. The electronic device defined in claim 15, wherein the processing circuitry is further configured to provide a graphical output to the display that depends on the magnitude of force of the touch input.

19. The electronic device defined in claim 15, further comprising a cover layer that covers the display.

20. The electronic device defined in claim 15, wherein the first capacitance and the second capacitance are associated with the force measurement layer and wherein the processing circuitry is further configured to determine a location of the touch input using the difference between the first capacitance of the force measurement layer and the second capacitance of the force measurement layer.