Differential acoustic touch and force sensing

Patent metadata

Field	Value
Publication number	US-11669199-B2
Application number	US-202117450441-A
Country	US
Kind code	B2
Filing date	Oct 8, 2021
Priority date	May 24, 2017
Publication date	Jun 6, 2023
Grant date	Jun 6, 2023

Abstract

Acoustic touch and/or force sensing system architectures and methods for acoustic touch and/or force sensing can be used to detect a position of an object touching a surface and an amount of force applied to the surface by the object. The position and/or an applied force can be determined using time-of-flight (TOF) techniques, for example. Acoustic touch sensing can utilize transducers (e.g., piezoelectric) to simultaneously transmit ultrasonic waves along a surface and through a thickness of a deformable material. The location of the object and the applied force can be determined based on the amount of time elapsing between the transmission of the waves and receipt of the reflected waves. In some examples, an acoustic touch sensing system can be insensitive to water contact on the device surface, and thus acoustic touch sensing can be used for touch sensing in devices that may become wet or fully submerged in water.

First claim

What is claimed is:

1. A sensing system comprising:
a transducer comprising:
a piezoelectric material including a first side and a second side, the second side opposite the first side;
a plurality of first electrodes disposed on the first side of the piezoelectric material;
one or more second electrodes disposed on the second side of the piezoelectric material; and

sensing circuitry coupled to the transducer and configured to perform a differential measurement of the plurality of first electrodes to sense a touch signal at one or more spatial modulation frequencies corresponding to a differential electrode configuration of sensing the plurality of first electrodes and reject a spatial common mode signal having a common spatial characteristic relative to the differential electrode configuration of sensing the plurality of first electrodes.

2. The sensing system of claim 1 , wherein:
the one or more second electrodes wrap around from the second side of the piezoelectric material to the first side of the piezoelectric material; and
the one or more second electrodes wrapped around to the first side of the piezoelectric material are separated from the first electrodes on the first side of the piezoelectric material by one or more gaps.

3. The sensing system of claim 1 , further comprising:
an insulating material disposed on a third side of the piezoelectric material, the third side of the piezoelectric material between the first side of the piezoelectric material and the second side of the piezoelectric material;
wherein the one or more second electrodes wrap around to a side of the insulating material that is coplanar with the first side of the piezoelectric material via the insulating material without contacting the third side of the piezoelectric material.

4. The sensing system of claim 1 , wherein:
the piezoelectric material further includes a third side between the first side of the piezoelectric material and the second side of the piezoelectric material;
the plurality of first electrodes wrap around from the first side of the piezoelectric material to the third side of the piezoelectric material;
the one or more second electrodes wrap around from the second side of the piezoelectric material to the third side of the piezoelectric material; and
the plurality of first electrodes wrapped around to the third side of the piezoelectric material and the one or more second electrodes wrapped around to the third side of the piezoelectric material are separated by one or more gaps.

5. The sensing system of claim 1 , further comprising:
an insulating material disposed on a third side of the piezoelectric material, the third side of the piezoelectric material between the first side of the piezoelectric material and the second side of the piezoelectric material, wherein:
the plurality of first electrodes wrap around from the first side of the piezoelectric material to the insulating material;
the one or more second electrodes wrap around from the second side of the piezoelectric material to the insulating material; and
the plurality of first electrodes wrapped around to the insulating material and the one or more second electrodes wrapped around to the insulating material are separated by one or more gaps.

6. The sensing system of claim 1 , wherein:
the piezoelectric material further includes a third side between the first side of the piezoelectric material and the second side of the piezoelectric material and a fourth side between the first side of the piezoelectric material and the second side of the piezoelectric material, the third side opposite the fourth side;
the plurality of first electrodes wrap around from the first side of the piezoelectric material to the third side of the piezoelectric material; and
the one or more second electrodes wrap around from the second side of the piezoelectric material to the fourth side of the piezoelectric material.

7. The sensing system of claim 1 , further comprising:
a first insulating material disposed on a third side of the piezoelectric material, the third side of the piezoelectric material between the first side of the piezoelectric material and the second side of the piezoelectric material; and
a second insulating material disposed on a fourth side of the piezoelectric material, the fourth side of the piezoelectric material between the first side of the piezoelectric material and the second side of the piezoelectric material and opposite the third side of the piezoelectric material, wherein:
the plurality of first electrodes wrap around from the first side of the piezoelectric material to the first insulating material, and
the one or more second electrodes wrap around from the second side of the piezoelectric material to the second insulating material.

8. The sensing system of claim 1 , wherein:
the plurality of first electrodes are separated from one another by a plurality of first gaps; and
the one or more second electrodes comprise a plurality of second electrodes separated from one another by a plurality of second gaps.

9. The sensing system of claim 1 , wherein:
the plurality of first electrodes are separated from one another by a plurality of first gaps, and
the one or more second electrodes consists of one second electrode.

10. The sensing system of claim 9 , further comprising:
an insulating material disposed on a third side of the piezoelectric material, the third side of the piezoelectric material between the first side of the piezoelectric material and the second side of the piezoelectric material, wherein:
the one second electrode wraps around to a side of the insulating material that is coplanar with the first side of the piezoelectric material via the insulating material without contacting the third side of the piezoelectric material.

11. The sensing system of claim 1 , wherein the plurality of first electrodes consists of two interlocking first electrodes separated by a gap.

12. The sensing system of claim 11 , further comprising:
an insulating material disposed on a third side of the piezoelectric material, the third side of the piezoelectric material between the first side of the piezoelectric material and the second side of the piezoelectric material, wherein:
the one or more second electrodes consists of one second electrode; and
the one second electrode wraps around to a side of the insulating material that is coplanar with the first side of the piezoelectric material via the insulating material without contacting the third side of the piezoelectric material.

13. The sensing system of claim 11 , wherein:
the piezoelectric material includes a third side between the first side of the piezoelectric material and the second side of the piezoelectric material and a fourth side between the first side of the piezoelectric material and the second side of the piezoelectric material, the third side of the piezoelectric material opposite the fourth side of the piezoelectric material;
the plurality of first electrodes consists of two first electrodes, one of the two first electrodes comprising a plurality of first conductive segments wrapping around to and electrically connected on the third side of the piezoelectric material and the other of the two first electrodes comprising a plurality of second conductive segments wrapping around to and electrically connected on the fourth side of the piezoelectric material; and
the one or more second electrodes wrap around the piezoelectric material from the second side of the piezoelectric material to the third side of the piezoelectric material.

14. The sensing system of claim 1 , further compris

Assignees

• Apple Inc

Inventors

• Yousefpor Marduke
• YEKE YAZDANDOOST Mohammad
• Tucker Aaron Scott
• Yip Marcus
• Khajeh Ehsan
• King Brian Michael
• Gozzini Giovanni

Classifications

• G06F2203/04106

  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 title

• G06F2203/04105

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

• G06F3/0436

  in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate · CPC title

• G06F3/043

  using propagating acoustic waves · CPC title

• G06F3/04166 Primary

  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 title