Piezo Based Force Sensing

• US 20190042046A1
• Filed: 09/28/2018
• Published: 02/07/2019
• Est. Priority Date: 10/28/2013
• Status: Abandoned Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Filiz, Sinan, Huppi, Brian Q., Butler, Christopher J., Grunthaner, Martin P., Shahparnia, Shahrooz, Kang, Sunggu, Wang, Kai
• Application Number:
  US16/145,627
• Publication Number:
  US 20190042046A1
• Time in Patent Office: Days
• CPC Class Codes: G01L 1/144 with associated circuitry G01L1/146 and G01L1/148 take precedence
• CPC Class Codes: G01L 1/146 for measuring force distributions, e.g. using force arrays G01L1/148 takes precedence
• CPC Class Codes: G01L 1/16 using properties of piezoelectric devices
• 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 3/04144 using an array of force sensing means position sensing using the local deformation of sensor cells G06F3/0447
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 17/964 Piezoelectric touch switches
• CPC Class Codes: H03K 17/9643 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2017/9602 characterised by the type or shape of the sensing electrodes
• CPC Class Codes: H03K 2217/96031 Combination of touch switch and LC display
• CPC Class Codes: H03K 2217/960735 characterised by circuit details
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches
• CPC Class Codes: H10N 30/302 Sensors

Abstract

Systems for detecting an amount and/or location of a force applied to a device using a piezoelectric film are provided. One example system can include a transparent piezoelectric film for generating an electric charge in response to a deformation of the film. Electrodes positioned on opposite surfaces of the piezoelectric film can be used to detect the generated electric charge and determine an amount and/or location of force applied to the film based on the generated electric charge. In another embodiment, the system can include a capacitive touch sensor for determining a location of a touch event on the device.

Claims

1-20. -20. (canceled)

21. A display stack, comprising:

a cover material defining an outer surface of the display stack and configured to receive a touch input from a user;

a touch input sensor substrate below the cover material;

a first touch input sensor electrode disposed on a first surface of the touch input sensor substrate;

a second touch input sensor electrode disposed on a second surface of the touch input sensor substrate;

a light-emitting layer below the touch input sensor substrate;

a force sensor layer below the light-emitting layer;

a first force sensor electrode disposed on the force sensor layer;

a second force sensor electrode disposed on the force sensor layer and aligned with the first force sensor electrode; and

sense circuitry operable to detect an electric charge generated by the force sensor layer in response to a deformation of the force sensor layer and the light-emitting layer that results from the touch input.

22. The display stack of claim 21, wherein:

the touch input sensor is coupled to the cover via a first adhesive layer;

the light-emitting layer is coupled to the touch input sensor a second adhesive layer; and

the force sensor layer is coupled to the light-emitting layer via a third adhesive layer.

23. The display stack of claim 22, wherein the first adhesive layer and the second adhesive layer comprise an optically clear adhesive.

24. The display stack of claim 21, wherein the light-emitting layer is an organic light emitting diode display.

25. The display stack of claim 21, wherein the first touch input sensor electrode is capacitively coupled to the second touch input sensor electrode.

26. The display stack of claim 21, wherein the first touch input sensor electrode and the second touch input sensor electrode are formed from a transparent conductive material.

27. The display stack of claim 21, wherein the force sensor layer comprises a piezoelectric material.

28. A display stack, comprising:

a touch input sensor comprising;

a transparent substrate;

a first touch input sensor electrode array disposed on a first surface of the transparent substrate; and

a second touch input sensor electrode array disposed on a second surface of the transparent substrate opposite the first touch input sensor electrode array;

an organic light-emitting diode display layer coupled to the touch input sensor;

a force sensor coupled to the organic light-emitting diode display layer and comprising;

a piezoelectric substrate;

a first force sensor electrode array disposed on the piezoelectric substrate; and

a second force sensor electrode array disposed on the piezoelectric substrate adjacent to the first force sensor electrode array; and

sense circuitry operable to detect an electric charge generated by the force sensor in response to a deformation of the light-emitting layer that results from a touch input to the touch input sensor.

29. The display stack of claim 28, wherein:

the first touch input sensor electrode array is disposed in a first pattern; and

the second touch input sensor electrode array is disposed in a second pattern.

30. The display stack of claim 29, wherein:

the first pattern comprises a first set of parallel electrodes; and

the second pattern comprises a second set of parallel electrodes perpendicular to the first set of parallel electrodes.

31. The display stack of claim 28, wherein the first force sensor electrode array comprises a grid of individual electrodes.

32. The display stack of claim 31, wherein the second force sensor electrode array comprises a grid of individual electrodes.

33. The display stack of claim 28, wherein:

the piezoelectric substrate is a first piezoelectric sheet; and

the display stack comprises;

a second piezoelectric sheet below the first piezoelectric sheet; and

a third force sensor electrode array disposed between the second piezoelectric sheet and the first piezoelectric sheet.

34. The display stack of claim 33, wherein the second force sensor electrode array comprises a grid of individual electrodes.

35. The display stack of claim 33, wherein the third force sensor electrode array comprises a shared ground electrode.

36. A display stack, comprising:

a transparent outer cover;

a light-emitting layer below the transparent outer cover; and

a force sensor adhered to the light-emitting layer and comprising;

a first force-sensing film;

a first force sensor electrode array disposed on a first surface of the first force-sensing film;

a shared electrode disposed on a second surface of the first force-sensing film, the second surface opposite the first surface;

a second force-sensing film coupled to the shared electrode; and

a second force sensor electrode array disposed on the second force-sensing film opposite the shared ground electrode.

37. The display stack of claim 36, wherein the shared ground electrode is coupled to circuit ground.

38. The display stack of claim 36, wherein:

the first force-sensing film comprises a first piezoelectric material; and

the second force-sensing film comprises a second piezoelectric material.

39. The display stack of claim 38, wherein the first piezoelectric material is the same as the second piezoelectric material.

40. The display stack of claim 36, further comprising a transparent capacitive touch input sensor adhered to the protective outer cover and positioned above the light-emitting layer.