Ultrasound-Based Force Sensing

• US 20160054826A1
• Filed: 06/01/2015
• Published: 02/25/2016
• Est. Priority Date: 07/26/2012
• Status: Abandoned Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Huppi, Brian Q., Grunthaner, Martin P., Filiz, Sinan, Hotelling, Steven P., Elias, John G.
• Application Number:
  US14/727,839
• Publication Number:
  US 20160054826A1
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 3/043 using propagating acoustic waves
• 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: H03K 17/96 Touch switches specially adapted for electronic time-pieces with no moving parts G04G21/08
• CPC Class Codes: H03K 17/9618 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/96011 with propagation, SAW or BAW
• CPC Class Codes: H03K 2217/96031 Combination of touch switch and LC display

Abstract

A force sensing device for computer or electronic devices. The force sensing device is configured to determine an amount of force applied, and changes in amounts of force applied, by the user when contacting a device, such as a touch device, and which can be incorporated into devices using touch recognition, touch elements of a graphical user interface, and touch input or manipulation in an application program. Additionally, the force sensing device may determine an amount of force applied, and changes in amounts of force applied, by the user when contacting a device, such as a touch device, and in response thereto, provide additional functions available to a user of a touch device, track pad, or the like.

Claims

1. An electronic device, including:

a housing;

an electronic component at least partially surrounded by the housing and connected to the housing;

one or more force sensitive sensors positioned beneath the electronic component and providing information with respect to applied force, the information including a measure of an amount of force presented at the one or more locations on an exterior of the device at which a touch occurs;

wherein

the force sensitive sensors are responsive to an ultrasonic pulse emitted through the electronic component and reflected from a surface of the device corresponding to the applied force.

2. A device as in claim 1, wherein:

the electronic component is a touch-sensitive display;

the one or more force sensitive sensors are positioned beneath the display and a corresponding display stack; and

the ultrasonic pulse is emitted through, and returns through, the display and the display stack.

3. A device as in claim 1, wherein

the one or more force sensitive sensors are responsive to a change in the applied force and a change in the location at which the contact occurs.

4. A device as in claim 1, wherein

the one or more force sensitive sensors include one or more force sensing elements, each one of the one or more force sensing elements being disposed to determine an amount of applied force at a portion of the surface of the display.

5. A device as in claim 1, wherein:

each of the force sensitive sensors comprise;

an ultrasonic pulse generator disposed to direct an ultrasonic pulse toward a portion of the surface; and

a receiver coupled to a reflection of the ultrasonic pulse from the surface and disposed to receive the reflection from the portion of the surface; and

the device further comprises a measurement element to determine an amount of applied force at the portion of the surface based on the reflection.

6. A device as in claim 2, further comprising:

an ultrasonic pulse generator disposed to direct an ultrasonic pulse through the display and display stack;

a measurement element to determine an amount of applied force at the surface;

a touch-sensing circuit operative to sense touch during a period in which the ultrasonic pulse is not traveling through the display and display stack; and

wherein

each of the force sensitive circuits comprises a receiver to receive reflection of the ultrasonic pulse from the surface.

7. A device as in claim 6, wherein

the measurement element to determine a location of applied force at the surface.

8. A method for estimating a force applied to a surface, comprising:

emitting an ultrasonic pulse towards a surface and through an electronic component;

receiving a reflected ultrasonic signal from the surface, the reflected ultrasonic signal traveling through the component;

determining a difference in energy between the ultrasonic pulse and the reflected ultrasonic signal; and

estimating a force from the difference in energy.

9. The method of claim 8, further comprising the operation of employing the force as an input to a computing device.

10. The method of claim 8, wherein the reflected ultrasonic signal is at least partially reflected from the surface.

11. The method of claim 10, further comprising the operation of accounting for an attenuation of at least one of the ultrasonic pulse and the reflected ultrasonic signal prior to the operation of determining the difference in energy.

12. The method of claim 8, further comprising the operations of:

defining a temporal transmission window;

defining a temporal reception window;

wherein

the operation of emitting the ultrasonic pulse towards the surface occurs only during the temporal transmission window; and

the operation of receiving the reflected ultrasonic signal from the surface occurs only during the temporal reception window.

13. The method of claim 12, wherein the temporal transmission window and the temporal reception window do not overlap.

14. The method of claim 13, wherein an end of the temporal transmission window is separated by approximately 450 nanoseconds from a beginning of the temporal reception window.

15. The method of claim 8, further comprising the operations of:

comparing the difference in energy to a prior-determined difference in energy between a prior ultrasonic pulse and a prior reflected ultrasonic signal; and

based on the comparison, determining if an object is touching the surface.

16. An apparatus for accepting a force as an input, comprising:

at least one ultrasonic emitter;

an optically transparent surface disposed above the at least one ultrasonic transmitter;

a display disposed beneath the optically transparent surface and above the at least one ultrasonic emitter;

at least one ultrasonic receiver positioned below the at least one ultrasonic emitter; and

a measurement element operative to estimate a force applied to the optically transparent surface, the estimation based on an attenuation of an ultrasonic pulse emitted from the ultrasonic emitter, reflected from the optically transparent surface and received by the ultrasonic receiver.

18. The apparatus of claim 16, wherein the optically transparent surface comprises a glass.

19. The apparatus of claim 16, wherein the at least one ultrasonic emitter comprises a piezoelectric film.

20. The apparatus of claim 16, further comprising a processor operatively connected to the at least one ultrasonic receiver and configured to estimate a force exerted on the optically transparent surface based on a signal received by the at least one ultrasonic receiver.

17. (canceled)