METHODOLOGY AND APPLICATION OF ACOUSTIC TOUCH DETECTION

• US 20180032211A1
• Filed: 07/28/2017
• Published: 02/01/2018
• Est. Priority Date: 07/29/2016
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: KING, Brian Michael, YEKE YAZDANDOOST, Mohammad, KHAJEH, Ehsan, TUCKER, Aaron Scott, GOZZINI, Giovanni, YIP, Marcus, YOUSEFPOR, Marduke, JADHAV, Digvijay, SEN, Indranil, NARANG, Mohit, JIANG, Yi, MAJIDZADEH BAFAR, Vahid, KERAMAT, Mansour, XU, Hao
• Granted Patent: US 11,402,950 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 1/1694 the I/O peripheral being a single or a set of motion sensors for pointer control or gesture input obtained by sensing movements of the portable computer
• CPC Class Codes: G06F 1/1698 the I/O peripheral being a sending/receiving arrangement to establish a cordless communication link, e.g. radio or infrared link, integrated cellular phone details of antennas disposed inside a computer H01Q1/2266
• CPC Class Codes: G06F 1/3231 Monitoring the presence, absence or movement of users
• CPC Class Codes: G06F 1/325 Power saving in peripheral device
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 2200/1637 Sensing arrangement for detection of housing movement or orientation, e.g. for controlling scrolling or cursor movement on the display of an handheld computer
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• 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 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/0433 in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate
• CPC Class Codes: H01Q 1/002 Protection against seismic waves, thermal radiation or other disturbances, e.g. nuclear explosion; Arrangements for improving the power handling capability of an antenna
• CPC Class Codes: H01Q 1/52 Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure absorbing means H01Q17/00
• CPC Class Codes: H01Q 7/005 with variable reactance for tuning the antenna
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Acoustic touch detection (touch sensing) system architectures and methods can be used to detect an object touching a surface. Position of an object touching a surface can be determined using time-of-flight (TOF) bounding box techniques, or acoustic image reconstruction techniques, for example. Acoustic touch sensing can utilize transducers, such as piezoelectric transducers, to transmit ultrasonic waves along a surface and/or through the thickness of an electronic device. Location of the object can be determined, for example, based on the amount of time elapsing between the transmission of the wave and the detection of the reflected wave. An object in contact with the surface can interact with the transmitted wave causing attenuation, redirection and/or reflection of at least a portion of the transmitted wave. Portions of the transmitted wave energy after interaction with the object can be measured to determine the touch location of the object on the surface of the device.

Claims

1. An acoustic sensing system, comprising:

a surface;

a plurality of ultrasonic transceivers coupled to edges of the surface; and

a processor coupled to the plurality of ultrasonic transceivers and configured to;

determine a first time of flight between a first ultrasonic wave generated by a first transceiver of the plurality of transceivers and a first reflection received at the first transceiver;

determine a second time of flight between a second ultrasonic wave generated by a second transceiver of the plurality of transceivers and a second reflection received at the second transceiver;

detect, based on at least one of the first time of flight or the second time of flight, an object in contact with the surface; and

determine a location of the object based on at least the first time of flight and the second time of flight.

2. The acoustic sensing system of claim 1, the processor further configured to:

determine a first location of a first edge of the object based on the first time of flight and a second location of a second edge of the object based on the second time of flight; and

determine the location of the object based on the first location of the first edge, the second location of second edge, and a dimension of the object.

3. The acoustic sensing system of claim 1, the processor further configured to:

determine a third time of flight between a third ultrasonic wave generated by a third transceiver of the plurality of transceivers and a third reflection received at the third transceiver;

determine a fourth time of flight between a fourth ultrasonic wave generated by a fourth transceiver of the plurality of transceivers and a fourth reflection received at the fourth transceiver;

detect, based on at least one of the first time of flight, the second time of flight, the third time of flight, or the fourth time of flight, the object in contact with the surface; and

determine the location of the object based on at least the first time of flight, the second time of flight, the third time of flight and the fourth time of flight.

4. The acoustic sensing system of claim 3, the processor further configured to:

determine a first location of a first edge of the object based on the first time of flight, a second location of a second edge of the object based on the second time of flight, a third location of a third edge of the object based on the third time of flight, and a fourth edge of the object based on the fourth time of flight; and

determine the location of the object based on the first location of the first edge, the second location of second edge, the third location of the third edge, and the fourth location of the fourth edge.

5. The acoustic sensing system of claim 4, wherein determining the location of the object comprises determining a centroid of the object based on a bounding box formed by the first edge, the second edge, the third edge, and the fourth edge.

6. The acoustic sensing system of claim 3, the processor further configured to:

determine a fifth time of flight between the first ultrasonic wave generated by the first transceiver of the plurality of transceivers and a fifth reflection received at the first transceiver;

determine a sixth time of flight between the second ultrasonic wave generated by the second transceiver of the plurality of transceivers and a sixth reflection received at the second transceiver;

determine a seventh time of flight between the third ultrasonic wave generated by the third transceiver of the plurality of transceivers and a seventh reflection received at the third transceiver;

determine an eighth time of flight between the fourth ultrasonic wave generated by the fourth transceiver of the plurality of transceivers and an eighth reflection received at the fourth transceiver;

detect, based on at least one of the first time of flight, the second time of flight, the third time of flight, the fourth time of flight, the fifth time of flight, the sixth time of flight, the seventh time of flight, or the eighth time of flight, an additional object in contact with the surface; and

determine a location of the additional object based on the location of the object and based on the first time of flight, the second time of flight, the third time of flight, the fourth time of flight, the fifth time of flight, the sixth time of flight, the seventh time of flight, and the eighth time of flight.

7. The acoustic sensing system of claim 3, the processor further configured to:

determine a fifth time of flight between a fifth ultrasonic wave generated by the fifth transceiver of the plurality of transceivers and a fifth reflection received at the fifth transceiver;

determine a sixth time of flight between a sixth ultrasonic wave generated by the sixth transceiver of the plurality of transceivers and a sixth reflection received at the sixth transceiver;

determine a seventh time of flight between a seventh ultrasonic wave generated by the seventh transceiver of the plurality of transceivers and a seventh reflection received at the seventh transceiver;

determine an eighth time of flight between an eighth ultrasonic wave generated by the eighth transceiver of the plurality of transceivers and an eighth reflection received at the eighth transceiver;

detect, based on at least one of the first time of flight, the second time of flight, the third time of flight, the fourth time of flight, the fifth time of flight, the sixth time of flight, the seventh time of flight, or the eighth time of flight, an additional object in contact with the surface; and

determine the location of the object and a location of the additional object based on the first time of flight, the second time of flight, the third time of flight, the fourth time of flight, the fifth time of flight, the sixth time of flight, the seventh time of flight, and the eighth time of flight.

8. The acoustic sensing system of claim 1, wherein the first transceiver is coupled to a first edge of the surface and the second transceiver is coupled to a second edge of the surface, wherein the first edge is perpendicular to the second edge.

9. The acoustic sensing system of claim 1, wherein the first transceiver is coupled to a first edge of the surface, the second transceiver is coupled to a second edge of the surface, the third transceiver is coupled to a third edge of the surface, and the fourth transceiver is coupled to a fourth edge of the surface, wherein the first edge, second edge, third edge, and fourth edge are different edges of the surface.

10. The acoustic sensing system of claim 1, wherein at least two of the plurality of transceivers are mounted on at least one edge of the surface.

11. The acoustic sensing system of claim 1, wherein the surface is a display screen.

12. A method of sensing for an acoustic sensing system comprising a surface and a plurality of ultrasonic transceivers coupled to edges of the surface, the method comprising:

determining a first time of flight between a first ultrasonic wave generated by a first transceiver of the plurality of transceivers and a first reflection received at the first transceiver;

determining a second time of flight between a second ultrasonic wave generated by a second transceiver of the plurality of transceivers and a second reflection received at the second transceiver;

detecting, based on at least one of the first time of flight or the second time of flight, an object in contact with the surface; and

determining a location of the object based on at least the first time of flight and the second time of flight.

13. The method of claim 12, further comprising:

determining a first location of a first edge of the object based on the first time of flight and a second location of a second edge of the object based on the second time of flight; and

determining the location of the object based on the first location of the first edge, the second location of second edge, and a dimension of the object.

14. The method of claim 12, further comprising:

determining a third time of flight between a third ultrasonic wave generated by a third transceiver of the plurality of transceivers and a third reflection received at the third transceiver;

determining a fourth time of flight between a fourth ultrasonic wave generated by a fourth transceiver of the plurality of transceivers and a fourth reflection received at the fourth transceiver;

detecting, based on at least one of the first time of flight, the second time of flight, the third time of flight, or the fourth time of flight, the object in contact with the surface; and

determining the location of the object based on at least the first time of flight, the second time of flight, the third time of flight and the fourth time of flight.

15. The method of claim 14, further comprising:

determining a first location of a first edge of the object based on the first time of flight, a second location of a second edge of the object based on the second time of flight, a third location of a third edge of the object based on the third time of flight, and a fourth edge of the object based on the fourth time of flight; and

determining the location of the object based on the first location of the first edge, the second location of second edge, the third location of the third edge, and the fourth location of the fourth edge.

16. The method of claim 15, wherein determining the location of the object comprises determining a centroid of the object based on a bounding box formed by the first edge, the second edge, the third edge, and the fourth edge.

17. The method of claim 14, further comprising:

determining a fifth time of flight between the first ultrasonic wave generated by the first transceiver of the plurality of transceivers and a fifth reflection received at the first transceiver;

determining a sixth time of flight between the second ultrasonic wave generated by the second transceiver of the plurality of transceivers and a sixth reflection received at the second transceiver;

determining a seventh time of flight between the third ultrasonic wave generated by the third transceiver of the plurality of transceivers and a seventh reflection received at the third transceiver;

determining an eighth time of flight between the fourth ultrasonic wave generated by the fourth transceiver of the plurality of transceivers and an eighth reflection received at the fourth transceiver;

detecting, based on at least one of the first time of flight, the second time of flight, the third time of flight, the fourth time of flight, the fifth time of flight, the sixth time of flight, the seventh time of flight, or the eighth time of flight, an additional object in contact with the surface; and

determining a location of the additional object based on the location of the object and based on the first time of flight, the second time of flight, the third time of flight, the fourth time of flight, the fifth time of flight, the sixth time of flight, the seventh time of flight, and the eighth time of flight.

18. The method of claim 14, further comprising:

determining a fifth time of flight between a fifth ultrasonic wave generated by the fifth transceiver of the plurality of transceivers and a fifth reflection received at the fifth transceiver;

determining a sixth time of flight between a sixth ultrasonic wave generated by the sixth transceiver of the plurality of transceivers and a sixth reflection received at the sixth transceiver;

determining a seventh time of flight between a seventh ultrasonic wave generated by the seventh transceiver of the plurality of transceivers and a seventh reflection received at the seventh transceiver;

determining an eighth time of flight between an eighth ultrasonic wave generated by the eighth transceiver of the plurality of transceivers and an eighth reflection received at the eighth transceiver;

detecting, based on at least one of the first time of flight, the second time of flight, the third time of flight, the fourth time of flight, the fifth time of flight, the sixth time of flight, the seventh time of flight, or the eighth time of flight, an additional object in contact with the surface; and

determining the location of the object and a location of the additional object based on the first time of flight, the second time of flight, the third time of flight, the fourth time of flight, the fifth time of flight, the sixth time of flight, the seventh time of flight, and the eighth time of flight.

19. A non-transitory computer readable storage medium storing instructions, which when executed by a device comprising a surface, a plurality of ultrasonic transceivers coupled to edges of the surface, and one or more processors, cause the one or more processors to perform a method comprising:

determining a first time of flight between a first ultrasonic wave generated by a first transceiver of the plurality of transceivers and a first reflection received at the first transceiver;

determining a second time of flight between a second ultrasonic wave generated by a second transceiver of the plurality of transceivers and a second reflection received at the second transceiver;

detecting, based on at least one of the first time of flight or the second time of flight, an object in contact with the surface; and

determining a location of the object based on at least the first time of flight and the second time of flight.

20. The non-transitory computer readable storage medium storing instructions, which when executed by the device comprising the surface, the plurality of ultrasonic transceivers coupled to edges of the surface, and the one or more processors, cause the one or more processors to perform the method of claim 19 further comprising:

determining a third time of flight between a third ultrasonic wave generated by a third transceiver of the plurality of transceivers and a third reflection received at the third transceiver;

determining a fourth time of flight between a fourth ultrasonic wave generated by a fourth transceiver of the plurality of transceivers and a fourth reflection received at the fourth transceiver;

detecting, based on at least one of the first time of flight, the second time of flight, the third time of flight, or the fourth time of flight, the object in contact with the surface; and

determining the location of the object based on at least the first time of flight, the second time of flight, the third time of flight and the fourth time of flight.

21. An electronic device comprising:

a plurality of acoustic touch sensors capable of detecting whether an object is contacting a specified portion of a surface of the electronic device, wherein a first acoustic touch sensor of the plurality of acoustic touch sensors comprises;

a transducer coupled to a first side of the surface and configured to detect an object contacting a second opposing side of the surface.

22. The electronic of claim 21, wherein the transmitted acoustic energy is a compressive wave transmitted from the first side toward the direction of the opposing first side of the surface.

23. The electronic device of claim 22, wherein the acoustic touch sensor is configured to transmit acoustic energy through the surface toward the second opposing side of the surface, and the acoustic touch sensor is capable of detecting whether the object is contacting the second opposing side directly across from the acoustic touch sensor.

24. The electronic device of claim 21, wherein the acoustic touch sensor is configured to transmit acoustic along the first side of the surface, and the acoustic touch sensor is capable of detecting whether the object is contacting a second side of the surface in a location that is not directly across from the acoustic touch sensor.

25. The electronic device of claim 24, wherein the transmitted acoustic energy is a shear horizontal wave.

26. The electronic device of claim 24, wherein a portion of the surface is curved relative to the direction of motion of the transmitted acoustic energy, and the acoustic touch sensor is capable of detecting contact by an object on the curved portion of the surface.

27. A method comprising:

transmitting acoustic energy from a transducer along a surface of an electronic device; and

comparing received reflected energy to a baseline measurement to determine a presence and a location of an object contacting the surface, wherein the baseline measurement is a measurement of reflected acoustic energy from surface discontinuities at different positions along the surface of the electronic device.

28. An electronic device comprising:

an antenna element;

an acoustic touch sensor capable of detecting whether an object is contacting a surface of the electronic device proximate to the antenna element; and

control circuitry configured to;

in accordance with a determination that an object is contacting the surface of the electronic device proximate to the antenna element, adjusting a parameter of the antenna operation to compensate for the contacting object.

29. The electronic device of claim 28, wherein adjusting the parameter of the antenna operation comprises adjusting an antenna loop length for the antenna element.

30. The electronic device of claim 28, wherein adjusting the parameter of the antenna operation comprises adjusting a value of a variable load element.

31. The electronic device of claim 30 wherein the variable load element is a variable capacitor.

32. The electronic device of claim 28, wherein the acoustic touch sensor is coupled to a first side of the surface, the acoustic touch sensor is configured to transmit acoustic energy through the surface toward a second opposing side of the surface, and the acoustic touch sensor is capable of detecting whether the object is contacting the second opposing side directly across from the acoustic touch sensor.

33. The electronic device of claim 28, wherein the acoustic touch sensor is coupled to a first side of the surface, the acoustic touch sensor is configured to transmit acoustic along the first side of the surface, and the acoustic touch sensor is capable of detecting whether the object is contacting a second side of the surface in a location that is not directly across from the acoustic touch sensor.

34. An electronic device comprising:

a housing;

a plurality of acoustic transducers coupled to a surface of the housing;

sense circuitry coupled to the plurality of acoustic transducers and configured to detect acoustic energy received by the plurality of acoustic transducers;

an orientation sensor for detecting a rotational orientation of the electronic device; and

a processor configured to;

detect the rotational orientation of the electronic device;

display an application on a display of the electronic device based on the orientation of the device;

associate a first acoustic transducer of the plurality of acoustic transducers with a first input to the application in a first orientation;

based on a change in the rotational orientation of the device, dissociate the first acoustic transducer from the first input to the application; and

associate a second acoustic transducer of the plurality of acoustic transducers, different from the first acoustic transducer with the first input to the application in a second rotational orientation of the electronic device.

35. The electronic device of claim 34, wherein the first acoustic transducer is associated with a second input to the application in the second orientation.

36. An acoustic touch sensing system, comprising:

an acoustic touch sensing circuit configured to perform a first detection scan of a surface and configured to perform a second detection scan of the surface; and

one or more processors coupled to the acoustic touch sensing circuit;

wherein at least one of the acoustic touch sensing circuit or the one or more processors is capable of processing results of the first detection scan or results of the second detection scan;

wherein the results of the first detection scan indicate a presence of an object touching the surface; and

wherein the results of the second detection scan indicate a location of the object touching the surface.

37. The acoustic touch sensing system of claim 36, wherein the one or more processors comprises a host processor and an auxiliary processor.

38. The acoustic touch sensing system of claim 37, wherein the auxiliary processor is configured to receive the results of the first detection scan and the results of the second detection scan;

and

wherein the auxiliary processor is capable of;

processing the results of the first detection scan to determine the presence of the object touching the surface; and

processing the results of the second detection scan to determine the location of the object touching the surface.

39. The acoustic touch sensing system of claim 38, wherein the acoustic touch sensing circuit is configured to average digital outputs of the first detection scan to generate the results of the first detection scan.

40. The acoustic touch sensing system of claim 38, wherein the acoustic touch sensing circuit is configured to average digital outputs of the second detection scan to generate the results of the second detection scan.

41. The acoustic touch sensing system of claim 37, wherein the auxiliary processor is configured to receive the results of the first detection scan and the host processor is configured to receive the results of the second detection scan;

wherein the auxiliary processor is capable of processing the results of the first detection scan to determine the presence of the object touching the surface; and

wherein the host processor is capable of processing the results of the second detection scan to determine the location of the object touching the surface.

42. The acoustic touch sensing system of claim 41, wherein the results of the first detection scan are transferred to the auxiliary processor by a first communication channel and the results of the second detection scan are transferred to the host processor by a second communication channel, wherein the second communication channel has a bandwidth greater than the first communication channel.

43. The acoustic touch sensing system of claim 36, further comprising:

an acoustic touch sensing digital signal processor configured to receive the results of the second detection scan;

wherein the acoustic touch sensing digital signal processor is capable of processing the results of the second detection scan to determine the location of the object touching the surface.

44. The acoustic touch sensing system of claim 36, wherein the acoustic touch sensing circuit is capable of processing the results of the first detection scan and the results of the second detection scan to determine the presence and the location of the object touching the surface.

45. The acoustic touch sensing system of claim 36, further comprising:

a plurality of transducers coupled to the surface; and

routing deposited along a side of the surface adjacent to the plurality of transducers;

wherein the acoustic touch sensing circuit is coupled to the plurality of transducers via coupling of the acoustic touch sensing circuit to the routing on the routing deposited along the side of the surface.

46. The acoustic touch sensing system of claim 36, further comprising:

a plurality of transducers coupled to the surface;

wherein the acoustic touch sensing circuit is coupled to the plurality of transducers via direct bonding between the plurality of transducers and the acoustic touch sensing circuit, via bonding between the plurality of transducers and a flexible circuit board coupled to the acoustic touch sensor circuit, or via bonding between the plurality of transducers and a rigid circuit board coupled to the acoustic touch sensor circuit.

47. The acoustic touch sensing system of claim 36, wherein the acoustic touch sensing circuit comprises an acoustic transmit circuit and an acoustic receive circuit;

wherein the acoustic transmit circuit is implemented on a first integrated circuit and the acoustic receive circuit is implemented on a second integrated circuit, separate from the first integrated circuit.

48. The acoustic touch sensing system of claim 36, further comprising a plurality of transmit transducers and a plurality of receive transducers;

wherein the acoustic touch sensing circuit is configured to generate an acoustic stimulation signal to apply to the plurality of transmit transducers; and

wherein the acoustic touch sensing circuit is configured to receive an acoustic receive signal from the plurality of receive transducers generated in response to the acoustic stimulation signal.

49. A method comprising:

performing a first acoustic detection scan of a surface;

processing results of the first acoustic detection scan to determine whether an object is contacting the surface;

in accordance with a determination that the object is contacting the surface, performing a second acoustic detection scan of the surface; and

processing results of the second acoustic detection scan to determine a location of the object contacting the surface.

50. The method of claim 49,

wherein performing the first acoustic detection scan comprises:

transmitting an acoustic wave into the surface from a first transducer; and

receiving an acoustic reflection corresponding to an edge of the surface opposite the first transducer at the first transducer; and

wherein processing the results of the first acoustic detection scan to determine whether to object is contacting the surface comprises;

determining that the object is contacting the surface when the received acoustic reflection corresponding to the edge of the surface is attenuated more than a threshold amount below a baseline received acoustic reflection corresponding to the edge of the surface.

51. The method of claim 49,

wherein performing the first acoustic detection scan comprises:

transmitting an acoustic wave into the surface from a first transducer; and

receiving the acoustic wave at a second transducer opposite the first transducer; and

processing the results of the first acoustic detection scan to determine whether to object is contacting the surface comprises;

determining that the object is contacting the surface when the received acoustic wave is attenuated more than a threshold amount below a baseline received acoustic wave.

52. The method of claim 49, wherein performing the second acoustic detection scan comprises:

transmitting, by a first transducer of a plurality of transducers, a first acoustic wave in the surface;

receiving, by the first transducer of the plurality of transducers, a first acoustic reflection in the surface;

transmitting, by a second transducer of the plurality of transducers, a second acoustic wave in the surface;

receiving, by the second transducer of the plurality of transducers, a second acoustic reflection in the surface;

transmitting, by a third transducer of the plurality of transducers, a third acoustic wave in the surface;

receiving, by the third transducer of the plurality of transducers, a third acoustic reflection in the surface;

transmitting, by a fourth transducer of the plurality of transducers, a fourth acoustic wave in the surface; and

receiving, by the fourth transducer of the plurality of transducers, a fourth acoustic reflection in the surface.

53. The method of claim 52, wherein processing the results of the second acoustic detection scan to determine the location of the object contacting the surface further comprises:

determining a first time of flight between the transmitted first acoustic wave and the received first acoustic reflection;

determining a second time of flight between the transmitted second acoustic wave and the received second acoustic reflection;

determining a third time of flight between the transmitted third acoustic wave and the received third acoustic reflection;

determining a fourth time of flight between the transmitted fourth acoustic wave and the received fourth acoustic reflection; and

determining the location of the object based on the first time of flight, the second time of flight, the third time of flight, and the fourth time of flight.

54. The method of claim 49,

wherein performing the first acoustic detection scan comprises:

transmitting an acoustic wave into the surface from a first transducer on a first side of the surface; and

receiving an acoustic reflection corresponding to an edge of the surface opposite the first transducer at a second transducer on the first side of the surface; and

wherein processing the results of the first acoustic detection scan to determine whether to object is contacting the surface comprises;

determining that the object is contacting the surface when the received acoustic reflection corresponding to the edge of the surface is attenuated more than a threshold amount below a baseline received acoustic reflection corresponding to the edge of the surface.

55. The method of claim 49, wherein performing the second acoustic detection scan comprises:

transmitting, by a first transmit transducer of a plurality of transducers, a first acoustic wave in the surface;

receiving, by a first receive transducer of the plurality of transducers, a first acoustic reflection in the surface, the first receive transducer collocated with the first transmit transducer;

transmitting, by a second transmit transducer of the plurality of transducers, a second acoustic wave in the surface;

receiving, by a second receive transducer of the plurality of transducers, a second acoustic reflection in the surface, the second receive transducer collocated with the second transmit transducer;

transmitting, by a third transmit transducer of the plurality of transducers, a third acoustic wave in the surface;

receiving, by a third receive transducer of the plurality of transducers, a third acoustic reflection in the surface, the third receive transducer collocated with the third transmit transducer;

transmitting, by a fourth transmit transducer of the plurality of transducers, a fourth acoustic wave in the surface; and

receiving, by a fourth receive transducer of the plurality of transducers, a fourth acoustic reflection in the surface, the fourth receive transducer collocated with the fourth transmit transducer.

56. The method of claim 55, wherein processing the results of the second acoustic detection scan to determine the location of the object contacting the surface further comprises:

determining a first time of flight between the transmitted first acoustic wave and the received first acoustic reflection;

determining a second time of flight between the transmitted second acoustic wave and the received second acoustic reflection;

determining a third time of flight between the transmitted third acoustic wave and the received third acoustic reflection;

determining a fourth time of flight between the transmitted fourth acoustic wave and the received fourth acoustic reflection; and

determining the location of the object based on the first time of flight, the second time of flight, the third time of flight, and the fourth time of flight.

57. A non-transitory computer readable storage medium storing instructions, which when executed by a device comprising a surface, a plurality of acoustic transducers coupled to edges of the surface, an acoustic touch sensing circuit, and one or more processors, cause the acoustic touch sensing circuit and the one or more processors to:

in a first state;

perform a first acoustic detection scan of the surface; and

process results of the first acoustic detection scan to determine whether an object is contacting the surface; and

in a second state;

perform a second acoustic detection scan of the surface; and

process results of the second acoustic detection scan to determine a location of the object contacting the surface.

58. The non-transitory computer readable storage medium of claim 57, further comprising instructions, which executed by the device, cause the acoustic touch sensing circuit to transition from the first state to the second state when the object is determined to be contacting the surface based on processing the results of the first acoustic detection scan.

59. The non-transitory computer readable storage medium of claim 57, further comprising instructions, which executed by the device, cause the acoustic touch sensing circuit to transition from the second state to the first state when no object is determined to be contacting the surface based on processing the results of the second acoustic detection scan for a threshold period of time or in response to receiving user input to power down a display of the device.

60. The non-transitory computer readable storage medium of claim 57, wherein the first acoustic detection scan and the second acoustic detection scan are performed by the acoustic touch sensing circuit.

61. The non-transitory computer readable storage medium of claim 57, wherein processing the results of the first acoustic detection scan is performed by a first processor of the one or more processors and processing the results of the second acoustic detection scan is performed by a second processor of the one or more processors.

62. An acoustic touch sensing system, comprising:

an acoustic touch sensing circuit configured to perform a touch detection scan of a surface;

wherein the acoustic touch sensing circuit is configured to generate results indicative of an object touching the surface at a first location when an input device contacts the surface at the first location and generate results indicative of no object touching the surface at a second location when a liquid contacts the surface at the second location.

63. An electronic device comprising:

a motion detector;

an antenna element;

an acoustic touch sensor capable of detecting whether an object is contacting a surface of the electronic device proximate to the antenna element; and

control circuitry configured to;

determine whether the electronic device is moving;

determine whether the object is contacting the surface of the electronic device proximate to the antenna element;

in accordance with a determination that the electronic device is not moving, operate the antenna element at a nominal power level; and

in accordance with a determination that the electronic device is moving and that the object is contacting the surface of the electronic device proximate to the antenna element, operate the antenna element at a reduced power level, lower than the nominal power level.

64. The electronic device of claim 63, wherein the control circuitry is further configured to:

in accordance with a determination that the electronic device is moving and that the object is not contacting the surface of the electronic device proximate to the antenna element, operate the antenna element at the nominal power level.

65. The electronic device of claim 63, wherein determining whether the electronic device is moving comprises determining whether motion detected by the motion detector is consistent with motion of a human body.

66. The electronic device of claim 63, wherein the acoustic touch sensor comprises:

an ultrasonic transducer; and

a plurality of reflective barriers on a surface of the electronic device, proximate to the antenna element, wherein the ultrasonic transducer transmits an acoustic wave toward the plurality of reflective barriers, and receives reflected signals from the barriers.

67. A method comprising:

determining whether an electronic device is moving;

determining whether an object is contacting a surface of the electronic device proximate to an antenna element;

in accordance with a determination that the electronic device is not moving, operating the antenna element at a nominal power level; and

in accordance with a determination that the electronic device is moving and that the object is contacting the surface of the electronic device proximate to the antenna element, operating the antenna element at a reduced power level, lower than the nominal power level.

68. The method of claim 67, wherein in accordance with a determination that the electronic device is moving and that the object is not contacting the surface of the electronic device proximate to the antenna element, operating the antenna element at the nominal power level.

69. The method of claim 67, wherein determining whether the electronic device is moving comprises determining whether motion detected by the motion detector is consistent with motion of a human body.

70. An electronic device comprising:

a configurable antenna element;

an acoustic touch sensor capable of detecting whether an object is contacting a surface of the electronic device proximate to the configurable antenna element; and

in accordance with a determination that the object is contacting the surface of the electronic device proximate to the configurable antenna element, adjusting a parameter of the configurable antenna element to compensate for presence of the object

71. The electronic device of claim 70, wherein the acoustic touch sensor is configured to detect contact directly in a transmission path of the configurable antenna element.

72. The electronic device of claim 70, wherein the acoustic touch sensor is capable of detecting whether an object is contacting a portion of the surface of the electronic device within a metal exclusion zone of the surface of the device.

73. The electronic device of claim 72, wherein the metal exclusion zone corresponds to a location of the configurable antenna element within the electronic device.

74. The electronic device of claim 70, wherein the acoustic touch sensor comprises:

an ultrasonic transducer; and

a plurality of reflective barriers on a surface of the electronic device, proximate to the antenna element, wherein the ultrasonic transducer transmits an acoustic wave toward the plurality of reflective barriers, and receives reflected signals from the barriers.

75. The electronic device of claim 74, wherein a first reflective barrier of the plurality of reflective barriers exhibits an anisotropic reflectance characteristic that depends upon a direction of travel of an acoustic wave encountering the first reflective barrier.

76. An electronic device comprising:

transmit circuitry configured to provide a stimulation signal to a transducer coupled to a surface of the device;

a plurality of surface discontinuities on a surface of the device located proximate to the transducer; and

receiver circuitry configured to capture a received signal based on motion of the transducer; and

control circuitry configured to;

couple the transmit circuitry to the transducer;

couple the receive circuitry to the transducer;

stimulate the transducer to produce an excitation in the surface of the device proximate to the transducer;

capture a first reflected energy at a first time based on a distance between the transducer and a first surface discontinuity of the plurality of surface discontinuities; and

capture a second reflected energy at a second time based on a distance between the transducer and a second surface discontinuity of the plurality of surface discontinuities,

wherein the second distance is greater than the first distance.

77. The electronic device of claim 76, wherein sampling the first reflected energy comprises integrating received energy during a first integration window interval based on a duration of the stimulation of the transducer and a distance between the transducer and the first surface discontinuity.

78. The electronic device of claim 77, wherein sampling the second reflected energy comprises integrating received energy during a second integration window having a same duration as the first integration window and beginning at a time after the first integration window begins.

79. The electronic device of claim 78, wherein the first integration window and the second integration window are non-overlapping.

80. The electronic device of claim 76, further comprising:

a filter configured to shape the stimulation signal based on a transfer function of a system formed by the transducer, the surface of the device, and the plurality of surface discontinuities on the surface of the device located proximate to the transducer.

81. The electronic device of claim 76, wherein the transducer is coupled to a cover glass of the device.

82. The electronic device of claim 81, wherein the cover glass comprises a transparent display region and a non-transparent border region, the transducer being coupled to the non-transparent border region.

83. The electronic device of claim 76, wherein the transducer is coupled to a metal housing of the device.

84. The electronic device of claim 76, further comprising a processor capable of determining a location of contact by an object with the surface of the device based on the first reflected energy and the second reflected energy.

85. The electronic device of claim 84, wherein the determination is based on a comparison between baseline values of the first reflected energy and the second energy and captured values of the first reflected energy and second reflected energy.

86. The electronic device of claim 85, wherein a determination that a difference between the first baseline value of the first reflected energy and the captured value of the first reflected energy exceeds a threshold difference corresponds to a contact by the object between the transducer and the first surface discontinuity of the plurality of surface discontinuities.

87. The electronic device of claim 76, further comprising:

a second transducer coupled to the surface of the device; and

a second plurality of surface discontinuities on the surface of the device located proximate to the second transducer;

wherein the control circuitry is further configured to;

decouple the transmit circuitry from the transducer;

couple the transmit circuitry to the second transducer;

decouple the receive circuitry from the transducer;

couple the receive circuitry to the second transducer;

stimulate the second transducer to produce an excitation in the surface of the device proximate to the second transducer;

capture a third reflected energy at a third time based on a distance between the transducer and a third surface discontinuity of the second plurality of surface discontinuities; and

capture a fourth reflected energy at a fourth time based on a distance between the transducer and a fourth surface discontinuity of the second plurality of surface discontinuities.

88. The electronic device of claim 87, further comprising:

a demultiplexer for selectively coupling and uncoupling the transmit circuitry from the transducer; and

a multiplexer for selectively coupling and decoupling the receive circuitry from the transducer.

89. The electronic device of claim 88, wherein the demultiplexer connects non-selected transducers to ground.