Electronic device with an integrated touch sensing and force sensing device

• US 10,152,187 B2
• Filed: 06/19/2017
• Issued: 12/11/2018
• Est. Priority Date: 09/26/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Krah, Christoph H.
• Primary Examiner(s): Chow, Van N
• Application Number:
  US15/627,058
• Publication Number:
  US 20170285810A1
• Time in Patent Office: 540 Days
• 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 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

An integrated touch sensing and force sensing device is included in an electronic device. The integrated touch sensing and force sensing device includes a force-sensitive layer operably attached to an input surface, a first electrode layer attached to a first surface of the force-sensitive layer, and a second electrode layer attached to a second surface of the force-sensitive layer. An analog front end processing channel is operable to process a touch signal that is based on a change in an electrical property between the first and second electrode layers and operable to process a force signal that is based on an electrical property generated by the force-sensitive layer based on a force applied to the input surface.

Claims

1. A method of power management in an integrated touch-sensing and force-sensing device, the method comprising:

detecting, at a force-sensitive layer of the integrated touch sensing and force sensing device, a force input to the integrated touch sensing and force sensing device while a touch-sensing operation of the integrated touch sensing and force sensing device is disabled;

enabling the touch-sensing operation in response to detecting the force input; and

detecting a touch input to the integrated touch sensing and force sensing device by detecting a change in an electrical property between a first electrode layer attached to a first surface of the force-sensitive layer and a second electrode layer attached to a second surface of the force-sensitive layer opposite the first surface.

2. The method of claim 1, wherein:

detecting the force input comprises;

processing the force input by a force processing channel to produce a force signal; and

determining that the force signal equals or exceeds a threshold value; and

enabling the touch-sensing operation in response to detecting the force input comprises;

enabling the touch-sensing operation when the force signal equals or exceeds the threshold value.

3. The method as in claim 1, further comprising processing a touch signal based on the touch input to the integrated touch sensing and force sensing device.

4. The method of claim 3, further comprising:

disabling the touch-sensing operation after processing the touch signal.

5. The method of claim 1, wherein enabling the touch-sensing operation comprises enabling circuitry in a touch processing channel.

6. The method of claim 5, wherein enabling circuitry in the touch processing channel comprises transitioning the circuitry from an off or lower power state to an operational state.

7. The electronic device of claim 1, wherein the first surface is opposite the second surface.

8. The electronic device of claim 1, wherein the force-sensitive layer comprises a piezoelectric layer.

9. The electronic device of claim 1, wherein the first and second electrode layers form a capacitive sensor.

10. The electronic device of claim 1, wherein the at least one of the first or second electrode layers is conductively coupled to the force-sensitive layer.

11. An electronic device, comprising:

an integrated touch sensing and force sensing device, comprising;

an input surface;

a force-sensitive layer attached to the input surface;

a first electrode layer attached to a first surface of the force sensitive layer; and

a second electrode layer attached to a second surface of the force-sensitive layer; and

an analog front end (AFE) processing channel operably connected to the integrated touch sensing and force sensing device, the AFE processing channel comprising;

a touch processing channel configured to process a touch signal that is based on a change in an electrical property between the first and second electrode layers; and

a touch power management channel configured to detect a force applied to the force-sensitive layer and, in response, enable a touch-sensing operation of the integrated touch sensing and force sensing device.

12. The electronic device of claim 11, wherein the force-sensitive layer comprises a piezoelectric layer.

13. The electronic device of claim 11, wherein enabling the touch-sensing operation comprises enabling circuitry of the touch processing channel.

14. The electronic device of claim 13, wherein enabling circuitry of the touch processing channel comprises transitioning the circuity from an off or lower power state to an operational state.

15. The electronic device of claim 11, wherein the touch power management channel comprises a comparator configured to compare a force signal corresponding to the force applied to the force sensitive layer to a threshold value, and to enable the touch-sensing operation based on the comparison.

16. The electronic device of claim 11, wherein:

the first electrode layer comprises a set of discrete electrodes;

the AFE processing channel further comprises a receiver AFE channel operably connected to at least one respective discrete electrode in the set of discrete electrodes;

the touch processing channel is operably connected to a first output of the AFE receiver channel; and

the touch power management channel is operably connected to a second output of the AFE receiver channel.

17. The electronic device of claim 16, wherein enabling the touch-sensing operation comprises enabling circuitry of the touch processing channel or the receiver AFE channel.

18. The electronic device of claim 17, wherein enabling circuitry of the touch processing channel comprises transitioning the circuity from an off or lower power state to an operational state.

19. The electronic device of claim 17, wherein the touch processing channel comprises:

a demodulator operably connected to the first output of the AFE receiver channel; and

an accumulator operably connected to an output of the demodulator;

wherein the enabled circuitry of the touch processing channel comprises the demodulator and the accumulator.

20. The electronic device of claim 11, wherein the touch power management channel is further configured to disable the touch-sensing operation after touch signal processing.