Systems and methods for acoustic touch and force sensing

Abstract

The present application relates to systems and methods for acoustic touch and force sensing. The present invention provides an acoustic touch and / or force sensing system architecture and a method for acoustic touch and / or force sensing, which can be used to detect the location of an object touching a surface and the amount of force applied by the object to the surface. For example, the time of flight (TOF) technology can be used to determine the location and / or the applied force. Acoustic touch sensing can use a transducer (e.g., piezoelectric) to simultaneously transmit ultrasonic waves along a surface and through the thickness of a deformable material. The location of the object and the applied force can be determined based on the amount of time that elapsed between transmitting the wave and receiving the reflected wave. In some examples, the acoustic touch sensing system may be insensitive to water contact on the surface of the device, so that acoustic touch sensing can be used for touch sensing in devices that may become wet or completely immersed in water.

Description

[0001] This application is a divisional application of the invention patent application with application date of May 24, 2018, application number 201810507207.6, and invention name “System and method for acoustic touch and force sensing”. Technical Field

[0002] The present invention relates generally to touch and / or force sensing systems and, more particularly, to integrated acoustic touch and force sensing systems and methods for acoustic touch and force sensing. Background Art

[0003] Currently, many types of input devices can be used to perform operations in computing systems, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens, and the like. In particular, touch screens have become increasingly popular due to their ease and flexibility in operation, as well as their decreasing price. A touch screen may include a touch sensor panel and a display device, such as a liquid crystal display (LCD). The touch sensor panel may be a transparent panel with a touch-sensitive surface, and the display device may be positioned partially or completely behind the panel so that the touch-sensitive surface covers at least a portion of the display device's viewable area. A touch screen allows a user to perform various functions by touching the touch sensor panel with a finger, stylus, or other object at a location often indicated by a user interface (UI) displayed by the display device. Generally speaking, a touch screen can identify a touch and its location on the touch sensor panel, and the computing system can then interpret the touch based on the displayed content appearing at the time of the touch, and can then perform one or more actions based on the touch. With some touch sensing systems, detecting a touch does not require a physical touch on the display. For example, in some capacitive touch sensing systems, the fringing electric field used to detect a touch may extend beyond the surface of the display, and objects approaching the surface may be detected as being near the surface without actually contacting the surface. However, capacitive touch sensing systems may experience performance degradation due to contact of conductive, electrically floating objects (eg, water droplets) with the touch-sensitive surface. Summary of the Invention

[0004] The present invention relates to acoustic touch and / or force sensing systems and methods for acoustic touch and / or force sensing. For example, time-of-flight (TOF) techniques can be used to determine the location of an object contacting a surface. Acoustic touch and / or force sensing utilizes a transducer (such as a piezoelectric transducer) to transmit ultrasonic waves along a surface and / or through the thickness of one or more materials (e.g., the thickness of an electronic device housing). As the waves propagate along the surface and / or through the thickness of one or more materials, an object (e.g., a finger, a stylus, etc.) in contact with the surface can interact with the transmitted waves, causing at least a portion of the transmitted waves to be reflected. The portion of the energy of the transmitted waves after interaction with the object can be measured to determine the touch location of the object on the device surface. For example, one or more transducers (e.g., acoustic transducers) coupled to the device surface can be configured to transmit acoustic waves along the surface and / or through the thickness of one or more materials and receive a portion of the reflected waves when the acoustic waves encounter a finger or other object touching the surface. For example, the location of the object can be determined based on the amount of time that elapses between the emission of the waves and the detection of the reflected waves. Acoustic touch sensing can be used in place of or in addition to other touch sensing technologies (such as resistive, optical, and / or capacitive touch sensing). In some embodiments, the acoustic touch sensing technology described herein can be used on metal housing surfaces of a device that may not be suitable for capacitive or resistive touch sensing due to interference (e.g., the housing has a capacitive or resistive sensor housed within the metal housing). In some embodiments, the acoustic touch sensing technology described herein can be used on glass surfaces of displays or touch screens. In some embodiments, the acoustic touch sensing system can be configured to be insensitive to water contact with the device surface, and thus acoustic touch sensing can be used for touch sensing on devices that may become wet or completely submerged in water.

[0005] In addition or alternatively, TOF technology can also be used to determine the force applied by an object on a surface. For example, one or more transducers can transmit ultrasonic waves through the thickness of a deformable material, and the reflected waves from the opposite edges of the deformable material can be measured to determine the TOF or a change in TOF. The TOF or the change in TOF (ΔTOF) can correspond to the thickness (or change in thickness) of the deformable material caused by the force applied to the surface. Therefore, the TOF or the change in TOF (or the thickness or the change in thickness) can be used to determine the applied force. In some embodiments, the use of acoustic touch and force sensing can reduce the complexity of the touch and force sensing system by reducing the sensing hardware requirements (for example, the transducers, sensing circuits / controllers, etc. can be integrated / shared). BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figures 1A to 1G An exemplary system with a touch screen that may include an acoustic sensor for detecting contact between an object and a surface of the system is shown in accordance with an embodiment of the present disclosure.

[0007] Figure 2 An exemplary block diagram of an electronic device including an acoustic touch and / or force sensing system according to an embodiment of the present disclosure is shown.

[0008] Figure 3A An exemplary process for acoustic touch and / or force sensing of an object in contact with a touch-sensitive and / or force-sensitive surface is shown in accordance with an embodiment of the present disclosure.

[0009] Figure 3B An exemplary system is shown that can perform exemplary processes for acoustic touch and / or force sensing of an object in contact with a touch-sensitive and / or force-sensitive surface in accordance with an embodiment of the present disclosure.

[0010] Figure 4 Exemplary configurations of acoustic touch and / or force sensing circuitry according to embodiments of the present disclosure are shown.

[0011] Figures 5A to 5C An exemplary system configuration and timing diagram for acoustic touch sensing using time-of-flight measurements to determine position according to an embodiment of the present disclosure is shown.

[0012] 6A to 6D An exemplary system configuration and timing diagram are shown for acoustic force sensing using time-of-flight measurements to determine the amount of applied force, according to an embodiment of the present disclosure.

[0013] Figure 7 A timing diagram for acoustic touch and force sensing is shown according to an embodiment of the present disclosure.

[0014] Figures 8A to 8C An exemplary circuit for force detection according to an embodiment of the present disclosure is shown.

[0015] Figure 9 Exemplary configurations of acoustic touch and / or force sensing circuitry according to embodiments of the present disclosure are shown.

[0016] Figures 10A to 10E Exemplary integration of acoustic touch and force sensing circuitry and / or one or more processors with transducers mechanically and acoustically coupled to a surface and / or deformable material according to embodiments of the present disclosure is shown.

[0017] Figure 11 An exemplary configuration of acoustic touch and force sensing circuitry according to an embodiment of the present disclosure is shown.

[0018] Figures 12A to 12E An exemplary integration of acoustic touch and force sensing circuitry and / or one or more processors with a transducer set mechanically and acoustically coupled to a surface and / or deformable material is shown in accordance with an embodiment of the present disclosure.

[0019] Figure 13 A first exemplary configuration for integrating touch-sensing and force-sensing circuitry with the housing and cover glass of an electronic device is shown.

[0020] Figure 14 A second exemplary configuration for integrating touch-sensing and force-sensing circuitry with the housing and cover glass of an electronic device is shown.

[0021] Figure 15 A third exemplary configuration for integrating touch-sensing and force-sensing circuitry with the housing and cover glass of an electronic device is shown.

[0022] Figure 16 A variation of the third configuration of FIG. 10 is shown with the addition of encapsulation material.

[0023] Figure 17 A fourth exemplary configuration for integrating touch-sensing and force-sensing circuitry with the housing and cover glass of an electronic device is shown.

[0024] Figure 18 A fifth exemplary configuration for integrating touch-sensing and force-sensing circuitry with a housing and cover glass of an electronic device is shown.

[0025] Figure 19A and 19B An exemplary configuration for integrating touch-sensing and force-sensing circuitry with shared elements with the housing and cover glass of an electronic device is shown. DETAILED DESCRIPTION

[0026] In the following description of the embodiments, reference will be made to the accompanying drawings which form a part of the following description, and in which are shown by way of example specific embodiments that may be implemented. It should be understood that other embodiments may be used and structural changes may be made without departing from the scope of the various embodiments.

[0027] The present invention relates to acoustic touch and / or force sensing systems and methods for acoustic touch and / or force sensing. For example, time-of-flight (TOF) techniques can be used to determine the location of an object contacting a surface. Acoustic touch and / or force sensing utilizes a transducer (such as a piezoelectric transducer) to transmit ultrasonic waves along a surface and / or through the thickness of one or more materials (e.g., the thickness of an electronic device housing). As the waves propagate along the surface and / or through the thickness of one or more materials, an object (e.g., a finger, a stylus, etc.) in contact with the surface can interact with the transmitted waves, causing at least a portion of the transmitted waves to be reflected. The portion of the energy of the transmitted waves after interaction with the object can be measured to determine the touch location of the object on the device surface. For example, one or more transducers (e.g., acoustic transducers) coupled to the device surface can be configured to transmit acoustic waves along the surface and / or through the thickness of one or more materials and receive a portion of the reflected waves when the acoustic waves encounter a finger or other object touching the surface. For example, the location of the object can be determined based on the amount of time that elapses between the emission of the waves and the detection of the reflected waves. Acoustic touch sensing can be used in place of or in addition to other touch sensing technologies (such as resistive, optical, and / or capacitive touch sensing). In some embodiments, the acoustic touch sensing technology described herein can be used on metal housing surfaces of a device that may not be suitable for capacitive or resistive touch sensing due to interference (e.g., the housing has a capacitive or resistive sensor housed within the metal housing). In some embodiments, the acoustic touch sensing technology described herein can be used on glass surfaces of displays or touch screens. In some embodiments, the acoustic touch sensing system can be configured to be insensitive to water contact with the device surface, and thus acoustic touch sensing can be used for touch sensing on devices that may become wet or completely submerged in water.

[0028] In addition or alternatively, TOF technology can also be used to determine the force applied by an object on a surface. For example, one or more transducers can transmit ultrasonic waves through the thickness of a deformable material, and the reflected waves from the opposite edges of the deformable material can be measured to determine the TOF or a change in TOF. The TOF or the change in TOF (ΔTOF) can correspond to the thickness (or change in thickness) of the deformable material caused by the force applied to the surface. Therefore, the TOF or the change in TOF (or the thickness or the change in thickness) can be used to determine the applied force. In some embodiments, the use of acoustic touch and force sensing can reduce the complexity of the touch and force sensing system by reducing the sensing hardware requirements (for example, the transducers, sensing circuits / controllers, etc. can be integrated / shared).

[0029] Figures 1A to 1GAn exemplary system with a touch screen that may include an acoustic sensor for detecting contact between an object (e.g., a finger or stylus) and a surface of the system according to an embodiment of the present disclosure is shown. Detecting contact may include detecting the location of the contact and / or the amount of force applied to the touch-sensitive surface. Figure 1A An exemplary mobile phone 136 is shown that includes a touch screen 124 and that may include acoustic touch and / or force sensing systems according to embodiments of the present disclosure. Figure 1B An exemplary digital media player 140 is shown that includes a touch screen 126 and that may include an acoustic touch and / or force sensing system according to embodiments of the present disclosure. Figure 1C An exemplary personal computer 144 is shown that includes a touch screen 128 and a trackpad 146 and that may include an acoustic touch and / or force sensing system according to embodiments of the present disclosure. Figure 1D An exemplary tablet computing device 148 is shown that includes a touch screen 130 and that may include an acoustic touch and / or force sensing system according to embodiments of the present disclosure. Figure 1E An exemplary wearable device 150 (eg, a watch) is shown that includes a touch screen 152 and can include acoustic touch and / or force sensing systems according to embodiments of the present disclosure. Wearable device 150 can be coupled to a user via a strap 154 ​​or any other suitable fastener. Figure 1F Another exemplary wearable device, over-ear headphones 160 , that may include an acoustic touch and / or force sensing system according to embodiments of the present disclosure is shown. Figure 1G Another exemplary wearable device, in-ear headphone 170, that may include an acoustic touch and / or force sensing system according to an embodiment of the present disclosure is shown. It should be understood that Figures 1A to 1G The exemplary devices shown are provided by way of example, and other types of devices may include acoustic touch and / or force sensing systems for detecting contact between an object and a surface of the device. Figures 1A to 1E The device shown in includes a touch screen, but in some embodiments the device may have a non-touch sensitive display (e.g., Figure 1F and Figure 1G ).

[0030] Acoustic sensors can be incorporated into the above-described systems to enhance acoustic touch and / or force sensing capabilities of system surfaces. For example, in some embodiments, a touch screen (e.g., capacitive, resistive, etc.) can be enhanced with acoustic sensors to provide touch and / or force sensing capabilities for use in humid environments or in conditions where the device may become wet (e.g., during exercise, swimming, rain, washing hands), or for use with non-conductive or partially conductive touch objects (e.g., a gloved or bandaged finger) or poorly grounded touch objects (e.g., an object not in contact with the device's system ground). In some embodiments, other non-touch-sensitive displays can be enhanced with acoustic sensors to provide touch and / or force sensing capabilities. In such embodiments, the touch screen can be implemented without the stack required for capacitive touch screens. In some embodiments, acoustic sensors can be used to provide touch and / or force sensing capabilities for non-display surfaces. For example, acoustic sensors can be used to provide touch and / or force sensing capabilities for a touchpad (e.g., touchpad 146 of personal computer 144), a button, a scroll wheel, part or all of a housing, or any other surface of a device (e.g., the front, back, or side). For example, acoustic sensors may be integrated into over-ear headphones 160 (e.g., outer circular area 162, inner circular area 164, and / or headband 166) or in-ear headphones 170 (e.g., earbuds 172 or protrusions 174) to provide touch and / or force input (e.g., single-touch or multi-touch gestures including taps, holds, and swipes). The acoustic sensing surface for acoustic touch and / or force sensing may be made of various materials (e.g., metal, plastic, glass, etc.) or combinations of materials.

[0031] Figure 2An exemplary block diagram of an electronic device including an acoustic touch and / or force sensing system according to an embodiment of the present disclosure is shown. In some embodiments, the housing 202 of the device 200 (e.g., corresponding to the above devices 136, 140, 144, 148, and 150) may be coupled (e.g., mechanically) to one or more acoustic transducers 204. In some embodiments, the transducer 204 may be a piezoelectric transducer that can be made to vibrate by applying an electrical signal when acting as a transmitter and generate an electrical signal based on the detected vibration when acting as a receiver. In some embodiments, the transducer 204 may be formed of a piezoelectric ceramic material (e.g., PZT or KNN) or a piezoelectric plastic material (e.g., PVDF or PLLA). Similarly, the transducer 204 can generate electrical energy as output when vibrated. In some embodiments, the transducer 204 can be bonded to the housing 202 by an adhesive (e.g., a thin layer of rigid epoxy). In some embodiments, the transducer 204 can be deposited on one or more surfaces (e.g., the cover glass and / or deformable material of the touch screen 208, as described in more detail below) by a process such as deposition, photolithography, etc. In some embodiments, the transducer 204 can be bonded to the one or more surfaces using a conductive or non-conductive adhesive material. When electrical energy is applied to the transducer 204, the transducer can be vibrated, and one or more surfaces in contact with the transducer can also be vibrated, and the vibrations of the molecules of the surface material can be propagated as sound waves through the one or more surfaces / materials. In some embodiments, the vibrations of the transducer 204 can be used to generate ultrasonic sound waves at a selected frequency across a wide frequency range (e.g., 500 kHz to 10 MHz) in a medium on the surface of the electronic device (which can be metal, plastic, glass, wood, etc.). It should be understood that other frequencies outside the above exemplary ranges can be used while still within the scope of the present disclosure.

[0032] In some embodiments, the transducer 204 may be partially or completely disposed on (or coupled to) a portion of the touch screen 208. For example, the (e.g., capacitive) touch screen 208 may include a glass panel (cover glass) or a plastic cover, and the display area of ​​the touch screen may be surrounded by a non-display area (e.g., a black border area around the perimeter of the display area of ​​the touch screen 208). In some embodiments, the transducer 204 may be partially or completely disposed in a black mask area of ​​the touch screen 208 (e.g., on the back side of the glass panel behind the black mask), so that the transducer is not visible (or only partially visible) to the user. In some embodiments, the transducer 204 may be partially or completely disposed on (or coupled to) a portion of a deformable material (not shown). In some embodiments, the deformable material may be disposed between the touch screen 208 and a rigid material (e.g., a portion of the housing 202). In some embodiments, the deformable material may be silicone, rubber, or polyethylene. In some embodiments, the deformable material may also be used to provide a watertight seal for the device.

[0033] Device 200 may also include acoustic touch and / or force sensing circuitry 206, which may include circuitry for driving electrical signals to stimulate vibration of transducer 204 (e.g., transmitting circuitry) and circuitry for sensing electrical signals output by transducer 204 when the transducer is stimulated by received acoustic energy (e.g., receiving circuitry). In some embodiments, timing operations for acoustic touch and / or force sensing circuitry 206 may optionally be provided by a separate acoustic touch and / or force sensing controller 210, which may control timing and other operations via acoustic touch and / or force sensing circuitry 206. In some embodiments, touch and / or force sensing controller 210 may be coupled between acoustic touch and / or force sensing circuitry 206 and host processor 214. In some embodiments, controller functionality may be integrated with acoustic touch and / or force sensing circuitry 206 (e.g., on a single integrated circuit). In particular, embodiments that integrate touch and force sensing circuitry and controller functionality into a single integrated circuit can reduce the number of transducers (sensor elements) and electronic chipsets used in touch and force sensing devices. Output data from acoustic touch and / or force sensing circuitry 206 can be output to host processor 214 for further processing to determine the location of an object contacting the device and the force exerted by the object, as will be described in more detail below. In some embodiments, the process for determining the location of the contacting object and the force exerted can be performed by acoustic touch and / or force sensing circuitry 206, acoustic touch and / or force sensing controller 210, or a separate sub-processor (not shown) of device 200.

[0034] In addition to acoustic touch and / or force sensing, device 200 may include additional touch circuitry 212 and, optionally, a touch controller (not shown) that may be coupled to touch screen 208. In embodiments that include a touch controller, the touch controller may be disposed between touch circuitry 212 and host processor 214. Touch circuitry 212 may be, for example, capacitive or resistive touch sensing circuitry and may be used to detect contact and / or hovering of an object (e.g., a finger, a stylus) in contact with and / or in proximity to touch screen 208, particularly within the display area of ​​the touch screen. Thus, device 200 may include multiple types of sensing circuitry (e.g., touch circuitry 212 and acoustic touch and / or force sensing circuitry 206) for detecting objects (and their positions and / or applied forces) in different areas of the device and / or for different purposes, as described in greater detail below. While described herein as including a touch screen, it should be understood that touch circuitry 212 may be omitted, and in some embodiments, touch screen 208 may be replaced by another non-touch-sensitive display (e.g., an acoustic sensor).

[0035] The host processor 214 can receive acoustic or other (e.g., capacitive) touch output and / or force output and perform actions based on the touch output and / or force output. The host processor 214 can also be connected to the program memory 216 and the touch screen 208. The host processor 214 can communicate with the touch screen 208, for example, to generate an image (such as an image of a user interface (UI)) on the touch screen 208, and can use the touch sensing circuit 212 and / or the acoustic touch and / or force sensing circuit 206 (and their respective controllers in some embodiments) to detect touches and / or applied forces (such as touch inputs and / or force inputs on a displayed UI) on or near the touch screen 208. Touch input and / or force input may be used by a computer program stored in program memory 216 to perform actions that may include, but are not limited to, moving an object such as a cursor or pointer, scrolling or panning, adjusting a control setting, opening a file or document, viewing a menu, making a selection, executing a command, operating a peripheral device connected to the host device, answering a phone call, placing a phone call, terminating a phone call, changing volume or audio settings, storing information related to telephone communications (such as addresses, frequently dialed numbers, received calls, missed calls), logging onto a computer or computer network, allowing authorized individuals to access restricted areas of a computer or computer network, loading a user profile associated with a user's preferred arrangement of a computer desktop, allowing access to web content, launching a specific program, encrypting or decrypting a message, etc. The host processor 214 may also perform additional functions that may not be related to touch and / or force processing.

[0036] It should be noted that one or more of the functions described herein may be performed by firmware stored in memory and executed by touch circuit 212 and / or acoustic touch and / or force sensing circuit 206 (or their respective controllers), or stored in program memory 216 and executed by host processor 214. The firmware may also be stored and / or transmitted in any non-transitory computer-readable storage medium for use by or in conjunction with an instruction execution system, apparatus, or device, such as a computer-based system, a system including a processor, or other system that can retrieve instructions from and execute instructions on an instruction execution system, apparatus, or device. In the context of this document, a "non-transitory computer-readable storage medium" can be any medium (excluding signals) that can contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. Non-transitory computer-readable medium storage may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, apparatus or devices, portable computer disks (magnetic), random access memory (RAM) (magnetic), read-only memory (ROM) (magnetic), erasable programmable read-only memory (EPROM) (magnetic), portable optical disks (such as CD, CD-R, CD-RW, DVD, DVD-R or DVD-RW), or flash memory (such as compact flash cards, secure digital cards), USB storage devices, memory sticks, etc.

[0037] The firmware may also be transmitted over any transmission medium for use by or in conjunction with an instruction execution system, device, or apparatus, such as a computer-based system, a system including a processor, or other system that can retrieve instructions from and execute instructions on an instruction execution system, device, or apparatus. In the context of this document, a "transmission medium" may be any medium that can convey, propagate, or transport a program for use by or in conjunction with an instruction execution system, device, or apparatus. Transmission-readable media may include, but are not limited to, electronic, magnetic, optical, electromagnetic, or infrared wired or wireless transmission media.

[0038] It should be understood that the device 200 is not limited to Figure 2 Rather, the components and configurations of the device 200 may include other components or additional components in a variety of configurations according to various embodiments. In addition, the components of the device 200 may be included in a single device or may be distributed among multiple devices. In addition, it should be understood that the connections between the components are exemplary and regardless of Figure 2 Depending on the configuration of the arrows shown, different unidirectional or bidirectional connections may be included between components.

[0039] Figure 3A An exemplary process 300 is shown for acoustic touch and / or force sensing of an object in contact with a touch-sensitive and / or force-sensitive surface according to an embodiment of the present disclosure. Figure 3BAn exemplary system 310 is shown that can perform an exemplary process 300 for acoustic touch and / or force sensing of an object in contact with a touch-sensitive and / or force-sensitive surface according to an embodiment of the present disclosure. For example, at 302, acoustic energy can be transmitted (e.g., via one or more transducers 204) in the form of ultrasonic waves along a surface and / or through the thickness of a material. For example, Figure 3B As shown, transducer 314 can generate transmitted ultrasonic waves 322 in cover glass 312 (or other material capable of propagating ultrasonic waves). In some embodiments, the waves can propagate as compression waves, guided waves (such as shear horizontal waves, Rayleigh waves, Lamb waves, Love waves, Stoneley waves), or surface acoustic waves. Other propagation modes for the transmitted acoustic energy may also exist based on the properties and geometry of the surface material, as well as the energy transmission method from the transducer to the device surface. In some embodiments, the surface can be formed of glass, plastic, or sapphire crystal (e.g., touch screen 208, cover glass 312), or the surface can be formed of metal, ceramic, plastic, or wood (e.g., housing 202). The transmitted energy can propagate along the surface (e.g., cover glass 312) and / or through the thickness until it reaches a discontinuity in the surface (e.g., by encountering an object in contact with the surface, such as finger 320), which can cause a portion of the energy to be reflected. In some embodiments, the discontinuity can occur at an edge of the surface material (e.g., edge 330) (e.g., when the ultrasonic wave propagates to the edge of the surface opposite the transducer). When the emitted energy reaches one of the above-mentioned interruptions, some of the energy may be reflected, and a portion of the reflected energy (e.g., object reflected wave 326, edge reflected wave 328) may be directed to one or more transducers (e.g., transducers 204, 314). In some embodiments, water or other fluid in contact with the surface of a device (e.g., device 200) will not interrupt the acoustic waves, and thus the acoustic touch sensing process can be effectively used to detect the presence of an object (e.g., a user's finger) even in the presence of water droplets (or other low-viscosity fluids) on the surface of the device or even when the device is completely submerged.

[0040] At 304, the returned acoustic energy may be received and converted into an electrical signal by one or more transducers (e.g., transducer 204). Figure 3B As shown, object reflection wave 326 and edge reflection wave 328 may be received by transducer 314 and converted into electrical signals.

[0041] At 306, the acoustic sensing system may determine whether one or more objects are in contact with the surface of the device, and may further detect the location of the one or more objects based on the received acoustic energy. In some embodiments, the distance of the object from the emission source (e.g., transducer 204) may be determined based on the transit time between the emission and reception of the reflected energy and the propagation rate of the ultrasonic wave through the material. In some embodiments, a baseline reflected energy from one or more intentionally included interruptions (e.g., edges) may be compared to the measurement of the reflected energy corresponding to the one or more interruptions. The baseline reflected energy may be determined during a measurement when no object (e.g., a finger) is in contact with the surface. Deviations in the reflected energy from the baseline may be associated with the presence of an object in contact with the surface.

[0042] Although process 300, as described above, generally refers to receiving reflected waves by the same transducer or transducers that transmitted the waves, in some embodiments, the transmitter and receiver functions can be separated such that the transmission of acoustic energy at 302 and the reception of acoustic energy at 304 can occur in different co-located transducers (e.g., one transducer in a transmitting configuration and another transducer in a receiving configuration). In some embodiments, acoustic energy can be transmitted along and / or through a surface (e.g., cover glass 312) by one or more transducers (e.g., transducer 314) and received at an opposite edge of the surface (e.g., edge 330) by one or more additional transducers (not shown). The attenuation of the received acoustic energy can be used to detect the presence and / or identify the location of one or more objects (e.g., finger 320) on the surface (e.g., cover glass 312). Example device configurations and measurement timing embodiments that can be used to implement process 300 are described in further detail below. In some embodiments, the transmitted acoustic energy from transducer 314 can be received at the transmitting transducer and also received by one or more other non-transmitting transducers located at different locations (e.g., at different edges of a surface (e.g., cover glass 312)). The energy can be reflected from one or more objects at multiple angles, and the energy received at all receiving transducers can be used to determine the location of the one or more objects. In some embodiments, the non-transmitting transducers can be free of distortion that can be associated with the transmitted acoustic energy (e.g., oscillations). In some embodiments, energy can be received by two transducers perpendicular to the transmitting transistor.

[0043] In some embodiments, acoustic energy transmitted and received through a deformable material can be used to determine changes in the thickness of the deformable material and / or the applied force. For example, at 302, acoustic energy may be transmitted (e.g., via transducer 314) in the form of transmitted ultrasonic waves 324 through the thickness of deformable material 316. The transmitted energy may propagate through deformable material 316 until it reaches a discontinuity in rigid material 318 (e.g., at opposing edges of deformable material 316). When the transmitted energy reaches the discontinuity, some of the energy may be reflected, and a portion of the reflected energy may be directed back to transducer 314. At 304, the returned acoustic energy may be received and converted by transducer 314 into an electrical signal. At 306, the acoustic sensing system may determine the amount of force applied by one or more objects contacting the surface (e.g., cover glass 312) based on the received acoustic energy. In some embodiments, the thickness of deformable material 316 may be determined based on the transit time between the transmission and reception of the reflected energy and the propagation rate of the ultrasonic wave through the material. As described in more detail below, the change in thickness of the deformable material (or the transit time through the deformable material) can be used to determine the amount of force applied.

[0044] Figure 4 FIG2 shows an exemplary configuration of an acoustic touch and / or force sensing circuit 400 according to an embodiment of the present disclosure. The acoustic touch and / or force sensing circuit 400 may include a transmitting circuit (also referred to herein as a Tx circuit or transmitter) 402, a switching circuit 404, a receiving circuit (also referred to herein as an Rx circuit or receiver) 408, and an input / output (I / O) circuit 420 (which together may correspond to the acoustic touch and / or force sensing circuit 206), and an acoustic scan control logic component 422 (which may correspond to the acoustic touch and / or force sensing controller 210). In some embodiments, the transmitter 402, the switching circuit 404, the receiver 408, the I / O circuit 420, and / or the acoustic scan control logic component 422 may be implemented in an application-specific integrated circuit (ASIC). In some embodiments, the acoustic touch and / or force sensing circuit 400 may also optionally include a transducer 406 (which may correspond to the transducer 204).

[0045] In some embodiments, transmitter 402 may generate an electrical signal for stimulating movement of one or more of multiple transducers 406. In some embodiments, the transmitted signal may be a differential signal, and in some embodiments, the transmitted signal may be a single-ended signal. In some embodiments, transmitter 402 may be a simple buffer, and the transmitted signal may be a pulse (or a pulse train at a specific frequency). In some embodiments, transmitter 402 may include a digital-to-analog converter (DAC) 402A and, optionally, a filter 402B, which may optionally be used to smooth the quantized output of DAC 402A. In some embodiments, the characteristics of the transducer itself may provide filtering properties, so filter 402B may be omitted. DAC 402A may be used to generate a transmit waveform (e.g., any transmit waveform suitable for touch and / or force sensing operations discussed herein). In some embodiments, the transmit waveform output may be pre-distorted to equalize the channels. In some embodiments, the characteristics of each channel (such as the surface material (and / or deformable material) coupled to transducer 406, the properties of discontinuities in the surface material and / or deformable material), and the reflective characteristics of the edge of the device or deformable material may be measured and stored. In some embodiments, the channel characteristics may be measured as a manufacturing step (or factory calibration step), and in other embodiments, the characteristics may be measured as a periodic calibration step (i.e., monthly, annually, etc., depending on the expected rate of change in the channel characteristics). In some embodiments, the channel characteristics may be converted into a transfer function of the channel, and the inverse of the channel transfer function may be used to configure the transmit waveform so that the return signal is balanced (e.g., although the transmit waveform has a seemingly arbitrary waveform, the return signal can be detected as a pulse or pulse train). In some embodiments, a single differential pulse may be used as the transmit waveform. For example, a bipolar rectangular pulse (in which the voltage applied to the transducer can be both positive and negative) may be used as the transmit waveform, and the bipolar rectangular pulse may be implemented using either a single-ended or differential implementation. In some embodiments, an energy recovery architecture may be used to recover some of the energy required to charge and discharge the transducer.

[0046] Switching circuitry 404 may include a multiplexer (MUX) and / or demultiplexer (DEMUX) that can be used to selectively couple transmitter 402 and / or receiver 408 to one of transducers 406, which may be the active transducer for a particular measurement step in a measurement cycle. In a differential implementation, switching circuitry 404 may include two MUXs and two DEMUXs. In some embodiments, the DEMUXs may have a ground connection, and unselected DEMUX outputs may be shorted, open, or connected to ground. In some embodiments, the same transducer 406 may be coupled to transmitter 402 via switching circuitry 404 (e.g., a DEMUX) during a drive mode and to receiver 408 via switching circuitry 404 (e.g., a MUX) during a receive mode. Thus, in some embodiments, a single transducer 406 may be used to both transmit and receive acoustic energy. In some embodiments, a first transducer can be coupled to transmitter 402 via switching circuitry 404 (e.g., a DEMUX), and a second transducer can be coupled to receiver 408 via switching circuitry 404 (e.g., a MUX). For example, the transmit and receive transducers can be separate piezoelectric elements, where the transmit transducer can be designed to be driven by a higher voltage (or current) to generate sufficient motion in transducer 406 to generate acoustic waves on the surface of a device (e.g., device 200 described above), and the receive transducer can be designed to receive smaller-amplitude reflected energy. In such a configuration, the transmit-side circuitry (e.g., transmitter 402 and the DEMUX of switching circuitry 404) can optionally be implemented on a high-voltage circuit, and the receive-side circuitry (e.g., receiver 408 and the MUX of switching circuitry 404) can optionally be implemented on a separate low-voltage circuit. In some embodiments, switching circuitry 404 (MUX and DEMUX) can also be implemented on a high-voltage circuit to properly isolate the remaining receive-side circuitry (e.g., receiver 408) during transmit operations of the transmit-side circuitry. Additionally or alternatively, in some embodiments, the transmit circuitry may include an energy recovery architecture that can be used to recover some of the energy required to charge and discharge the transducer. It should be understood that for a single-ended implementation, the switching circuitry 404 may include a single DEMUX and MUX. In such a configuration, the transmitter 402 and receiver 408 may also be single-ended. However, differential implementations may provide improved noise suppression compared to single-ended implementations.

[0047] Receiver 408 may include an amplifier 410, such as a low-noise amplifier (LNA) configured to sense the transducer. Receiver 408 may also include gain and offset correction circuitry 412. The gain and offset correction circuitry may include a programmable gain amplifier (PGA) configured to apply gain to increase (or, in some cases, decrease) the amplitude of a signal received from the LNA. The PGA may also be configured to filter (e.g., low-pass) the signal received from the LNA to remove high-frequency components. Furthermore, the PGA circuitry may also be configured to perform baseline (offset correction).

[0048] In some embodiments, the output of the gain and offset correction circuit 412 may optionally be coupled to one or more analog processing circuits. In some embodiments, the output of the gain and offset correction circuit 412 may be coupled to a demodulation circuit 414 configured to demodulate (e.g., via I / Q demodulation) the received signal. In some embodiments, the output of the gain and offset correction circuit 412 may be coupled to an envelope detection circuit 415 configured to perform envelope detection on the received signal. In some embodiments, the output of the gain and offset correction circuit 412 may be filtered at a filter 416. In some embodiments, these blocks / circuits may be placed in a different order. In some embodiments, processing by one or more of these analog processing circuits may be performed in the digital domain.

[0049] The received signal (whether raw or processed by one or more of demodulation circuit 414, envelope detection circuit 415, or filter 416) can be passed to analog-to-digital converter (ADC) 418 for conversion to a digital signal. In some embodiments, input / output (I / O) circuitry 420 can be used to transmit the received data for processing. In some embodiments, the output of I / O circuitry 420 can be transmitted to the device's host processor, or to an auxiliary processor (sub-processor) separate from the host processor. For example, as shown, the output of I / O circuitry 420 can be coupled to a processor system-on-chip (SoC) 430, which can include one or more processors. In some embodiments, processor SoC 430 can include a host processor 432 (e.g., an active mode processor) and an auxiliary processor 434 (e.g., a low-power processor). In some embodiments, some digital signal processing can be performed (e.g., by acoustic touch and / or force sensing circuitry 400) before the data is transmitted to other processors in the system (e.g., processor SoC 430). In some embodiments, I / O circuitry 420 is used not only for data transmission to processor SoC 430 (eg, host processor 432 ), but also for writing control registers and / or downloading firmware from processor SoC 430 .

[0050] The components of the receiver circuit 408 described above can be implemented to detect a touch (e.g., the presence and location of a touch on a surface). In some embodiments, the receiver 408 can also include a force detection circuit 424 to detect the force applied (e.g., a touch on the surface). In some embodiments, the force detection circuit 424 can include the same or similar components as described above (e.g., amplifier, gain, offset correction, etc.). In some embodiments, the functions of the force detection circuit 424 can be performed using the same components described above for determining the transit time for touch detection. In some embodiments, a low-power time-gating circuit can be used to determine the transit time for force detection. Data from the force sensing circuit 424 can be transmitted to the I / O circuit 420 and / or the processor SoC 430 for further processing of the force data using a formula similar to that described above for touch data. In some embodiments, the same circuitry used for touch detection can be used to detect force.

[0051] The control circuitry, acoustic scan control circuitry 422, may be used to control the timing and operation of the circuitry of the acoustic touch and / or force sensing circuitry 400. The acoustic scan control circuitry 422 may be implemented in hardware, firmware, software, or a combination thereof. In some examples, the acoustic scan control circuitry 422 may include digital logic and timing control. The digital logic may provide various components of the acoustic touch and / or sensing circuitry 400 with control signals. The timing control circuitry may generate timing signals for the acoustic touch and / or sensing circuitry 400 and generally sequence the operations of the acoustic touch and / or force sensing circuitry 400. In some examples, the acoustic touch and / or force sensing circuitry 400 may receive a master clock signal from an external source (e.g., a clock from a host processor, a crystal oscillator, a ring oscillator, an RC oscillator, or other high-performance oscillator). In some examples, an on-chip oscillator may be used to generate the clock. In some examples, the master clock signal may be generated by an on-chip phase-locked loop (PLL) included in and as part of the acoustic touch and / or force sensing circuitry 400 using the external clock as input. In some examples, a master clock signal can be routed to the acoustic touch sensing circuitry from the processor SoC 430. A suitable master clock source can be determined based on a tradeoff between area, stack-up thickness, power, and electromagnetic interference.

[0052] It should be understood that Figure 4 The configuration is not limited to Figure 4 Rather, the system may include other components or additional components (e.g., memory, signal processors, etc.) in a variety of configurations according to various examples. Figure 4 Some or all of the components shown may be included in a single circuit, or may be distributed among multiple circuits while remaining within the scope of the examples of the present disclosure.

[0053] As described herein, various acoustic sensing techniques can be used to determine the location of an object contacting a surface and / or the force it exerts on the surface. In some examples, one or more time-of-flight measurements can be performed using one or more acoustic transducers to determine the boundaries of the location of the contacting object. Figures 5A to 5C An exemplary system configuration and timing diagram are shown for acoustic touch sensing using time-of-flight measurements to determine position according to examples of the present disclosure. Figure 5A An exemplary acoustic touch sensing system configuration is shown using four acoustic transducers 502A to 502D mounted (or otherwise coupled) along the four edges of a surface 500 (e.g., corresponding to the cover glass 312). The transducers 502A to 502D can be configured to generate acoustic waves (e.g., shear horizontal waves) and receive reflected acoustic waves. Because low-viscosity fluids and gases (e.g., water and air) have very low shear moduli, the propagation of shear horizontal waves on the surface 500 can be unaffected by the water and, therefore, does not disrupt boundary conditions that affect wave propagation. Shear horizontal waves can be highly directional waves, making it possible to effectively define an effective detection area (or active area) 504 based on the location and size of the acoustic transducers 502A to 502D. However, it should be understood that the active area can vary based on the directional properties of the acoustic waves and the size and arrangement of the acoustic transducers 502A to 502D. Additionally, it should be understood that although shown as transmitting and receiving transducers (i.e., transceivers), in some examples, the transmit and receive functionality may be separated (e.g., between two transducers located proximate to each other, rather than in one transmit and receive transducer).

[0054] The location of touch 506 from an object in contact with surface 500 can be determined by calculating TOF measurements using each of acoustic transducers 502A to 502D during a measurement cycle. For example, in the first measurement step of the measurement cycle, acoustic transducer 502A can transmit an acoustic wave and receive reflections from the acoustic wave. When no object is present, the received reflections can be reflections from the acoustic wave reaching the opposite edge of surface 500. However, when an object touches surface 500 (e.g., corresponding to touch 506), a reflection corresponding to the object can be received before a reflection from the opposite edge. Based on the received reflection corresponding to the object received at transducer 502A, the system can determine the distance to the edge (e.g., the leading edge) of touch 506, marked by boundary line 510A. Similar measurements can be performed by transducers 502B, 502C, and 502D to determine the distance to the remaining edges of touch 506, indicated by boundary lines 510B, 510C, and 510D. Taken together, the measured distances represented by bounding lines 510A through 510D can form a bounding box 508. In some examples, based on the bounding box, the acoustic touch sensing system can determine the area of ​​the touch (e.g., the area of ​​the bounding box). Based on the bounding box, the acoustic touch sensing system can determine the location of touch 506 (e.g., based on the centroid and / or area of ​​the bounding box).

[0055] refer to Figure 5A The described acoustic touch sensing scan may correspond to the above reference Figure 3A and Figure 3B Acoustic touch detection as described. Acoustic waves transmitted and received along or through the cover glass 312 can be used to determine the position / orientation of an object touching the surface of the cover glass 312.

[0056] Figure 5B An example of the present disclosure is shown. Figure 5A An exemplary timing diagram 560 of an acoustic touch sensing scan as described in FIG. Figure 5B As shown, each transducer can transmit an acoustic wave and then receive a reflected wave in a series of measurement steps. For example, from t0 to t1, the first transducer (e.g., acoustic transducer 502A) can be excited, and the reflection at the first transducer can be received from t1 to t2. From t2 to t3, the second transducer (e.g., acoustic transducer 502B) can be excited, and the reflection at the second transducer can be received from t3 to t4. From t4 to t5, the third transducer (e.g., acoustic transducer 502C) can be excited, and the reflection at the third transducer can be received from t5 to t6. From t6 to t7, the fourth transducer (e.g., acoustic transducer 502D) can be excited, and the reflection at the fourth transducer can be received from t7 to t8. Although for each transducer, the transmit (Tx) and receive (Rx) functions are Figure 5B, but in some examples, gaps can be included between the Tx and Rx functions of a transducer (e.g., to minimize the capture of a portion of the transmitted wave at the receiver) and / or between the Tx / Rx functions of two different transducers (so that acoustic energy and transients caused by multiple reflections from the sweep of one transducer do not affect the sweep of the second transducer). In some examples, unused transducers can be grounded (e.g., by a multiplexer / demultiplexer in the switching circuit 404).

[0057] The distance between an object touching a surface and a transducer can be calculated based on the TOF principle. The acoustic energy received by the transducer can be used to determine timing parameters that indicate the leading edge of a touch. The propagation rate of acoustic waves through the material forming the surface can be a known relationship between distance and time. Together, this known relationship between distance and time and the timing parameters can be used to determine distance. Figure 5C An exemplary timing diagram according to examples of the present disclosure is shown. Figure 5C Transducer energy output versus time is shown. Signal 550 may correspond to acoustic energy at the transducer from an acoustic wave generated at a first edge of a surface. Signal 552 may correspond to acoustic energy received at the transducer from a wave reflected from a second edge opposite the first edge of the surface. Due to the known distance from the first edge to the opposite second edge on the surface and the known or measured propagation rate of the acoustic signal, the reflection from the opposite edge of the surface occurs at a known time. In addition, one or more objects (e.g., a finger) touching the surface may cause energy reflection in the time between the generation of the wave and the edge reflection (i.e., between signals 550 and 552). For example, signals 554 and 556 may correspond to reflections from two objects touching the surface (or the leading and trailing edges of an object). It should be understood that signals 550 to 556 are exemplary and that the actual shape of the received energy may vary in implementation.

[0058] In some examples, the timing parameter may be a moment in time that can be derived from the reflected energy. For example, the time may refer to the time at which a threshold amplitude of the reflected energy packet is detected. In some examples, a threshold energy of the reflected energy packet may be detected, rather than a threshold amplitude, and the time may refer to the time at which the threshold energy of the packet is detected. The threshold amplitude or threshold energy may indicate the leading edge of an object in contact with the surface. In some examples, the timing parameter may be a time range rather than a point in time. To improve the resolution of a TOF-based sensing scheme, the frequency of the ultrasonic wave and the sampling rate of the receiver may be increased (e.g., so that the reception of the reflected wave can be localized to a narrower peak that can be more accurately associated with a moment in time).

[0059] In some examples (e.g., Figure 5BAs shown in FIG. 1 , transducers 502A to 502D can be operated in a time-division multiplexed manner, such that each transducer transmits and receives acoustic waves at different times within a measurement cycle, so that waves from one transducer do not interfere with waves from another transducer. In other examples, the transducers can be operated in parallel or partially in parallel in time. The signals from the respective transducers can then be distinguished based on different characteristics of the signals (e.g., different frequencies, phases, and / or amplitudes).

[0060] Although Figure 5A Four transducers are shown in FIG, but in some examples, fewer transducers may be used. For example, when using an input object with known dimensions (e.g., a stylus or a finger of known dimensions), only two transducers mounted along two vertical edges may be used. Based on the known dimensions of the object, a bounding box 518 may be formed by adding the known dimensions of the object to the first distance and the second distance. Additionally, while Figure 5A Detection of a single object (e.g., a single touch) is shown, but in some examples, the acoustic touch sensing system can use multiple transducers and be configured to detect multiple touches (e.g., by replacing each of transducers 502A-502D with multiple smaller transducers).

[0061] refer to Figures 5A to 5C The described TOF scheme can provide touch sensing capabilities using a limited number of transducers (e.g., compared to the multiple electrodes / touch nodes of a capacitive touch sensing system), which can simplify transmit and receive electronics and can reduce processing time and memory requirements. Figures 5A to 5C The use of bounding boxes based on TOF measurements to determine the location of an object is discussed, but in other examples, different approaches can be used, including applying matched filtering to known transmitted ultrasound pulse shapes and using a centroid (e.g., rather than a centroid) calculation on the filtered output.

[0062] In some examples, time-of-flight measurements may be performed using one or more acoustic transducers to determine the amount of force exerted by an object touching the surface. 6A to 6D An exemplary system configuration and timing diagram are shown for acoustic force sensing using time-of-flight measurements to determine the amount of applied force according to examples of the present disclosure. Figure 6A An exemplary acoustic force sensing system stack-up structure 600 is shown that includes a deformable material 604 between two rigid surfaces. One of the rigid surfaces can be a cover glass 601 (e.g., corresponding to cover glass 312). The other rigid surface can be, for example, a portion of a device housing (e.g., corresponding to housing 202). An acoustic transducer 602 (e.g., corresponding to transducer 314) can be mounted to (or otherwise coupled to) the deformable material 604. For example, as Figure 6AAs shown, the transducer 602 can be disposed between the cover glass 601 and the deformable material 604. The transducer 602 can be configured to generate acoustic waves (e.g., shear horizontal waves) and receive reflected acoustic waves from discontinuities at the edge between the deformable material 604 and the rigid material 606. It should be understood that although shown as transmitting and receiving transducers (i.e., transceivers), in some examples, the transmitting and receiving functions can be separated (e.g., between two transducers located close to each other, rather than in one transmitting and receiving transducer). The shear horizontal waves can be highly directional waves, making time of flight an effective measure of the thickness of the deformable material. A baseline thickness (or time of flight) can be determined for a forceless condition, so that a change in thickness (Δd) (or time of flight) can be measured. The change in thickness or time of flight can correspond to the amount of force applied.

[0063] For example, Figure 6D Graph 630 shows an exemplary relationship between time of flight (or thickness) and applied force according to an example of the present disclosure. For example, under steady-state conditions, i.e., when the time of flight on the deformable material 604 does not change, the applied force may be zero. As the time of flight changes (e.g., decreases), the applied force may also change (e.g., increase). Graph 630 shows a linear relationship between TOF and force, but in some examples, the relationship may be nonlinear. The relationship between TOF and applied force can be determined empirically (e.g., at calibration) using correlation. In some examples, calibration can include linearizing the inferred applied force and normalizing the measurement results (e.g., removing gain and offset errors). In some examples, the Young's modulus of the deformable material may be selected to be below a threshold to allow smaller applied forces to introduce detectable normal deformation.

[0064] Figure 6B Another exemplary acoustic force sensing system stack-up structure 610 is shown that includes a deformable material 614 between two rigid surfaces (e.g., between a cover glass 611 and a rigid material 618). An acoustic transducer 612 can be mounted to (or otherwise coupled to) one side of the deformable material 614, and a second acoustic transducer 616 can be mounted to (or otherwise coupled to) a second side (opposite the first side) of the deformable material 614. For example, Figure 6BAs shown, transducer 612 can be disposed between cover glass 611 and deformable material 614, and transducer 616 can be disposed between rigid material 618 and deformable material 614. Transducer 612 can be configured to generate acoustic waves (e.g., shear horizontal waves), and transducer 616 can be configured to receive acoustic waves. The configuration of transducers in stacked structure 610 can be referred to as a "pitch-catch" configuration, where one transducer on one side of the material transmits an acoustic wave to a second transducer on the opposite side, rather than relying on reflected acoustic waves. The time of flight between the time of emission and the time of reception of the acoustic wave can be measured to compare with the above referenced time. Figure 6D The amount of force applied is determined in a similar manner as discussed above.

[0065] Figure 6C An exemplary timing diagram 640 is shown according to examples of the present disclosure. Figure 6C Transducer energy output versus time is shown. Signal 620 may correspond to acoustic energy at transducer 602 from an acoustic wave generated at a first edge of deformable material 604. Signal 622 may correspond to acoustic energy received at transducer 602 from a first wave reflected from a second edge opposite the first edge of deformable material 604. Due to the known distance from the first edge to the second edge (in steady state) on the surface and the known or measured propagation velocity of the acoustic signal, the reflection from the opposite edge of the surface occurs at a known time. In some examples, instead of using the first reflection, different reflections of the acoustic energy may be used to determine the time of flight. For example, signal 624 may indicate acoustic energy received at transducer 602 from a second wave reflected from the second edge of deformable material 604 (e.g., signal 622 may be reflected from the first side of deformable material 604 and again reflected from the second edge of deformable material 604). In some examples, signal 556 may correspond to an integer number of reflections following repeated reflections between two edges of deformable material 604. It should be understood that signals 620 to 626 are exemplary and that the actual shape of the received energy may vary in implementation. In some examples, the selection of reflections for time-of-flight calculations for force sensing may be a function of the thickness of the material and the frequency of the transmitted wave.

[0066] In some examples, rather than using time-of-flight measurements to determine the thickness of a deformable material, other methods can be used. For example, transducer 602 can excite deformable material 604 using ultrasound at a resonant frequency. When deformable material 604 changes due to an applied force, the resonant frequency can shift. The change in resonant frequency can be measured to determine the applied force. Using the resonant frequency can result in better signal-to-noise ratio (SNR) performance and greater accuracy compared to time-of-flight methods.

[0067] As mentioned above Figures 3A to 3BAs described, in some examples, both acoustic touch and force sensing can be performed. In some examples, these two operations can be time-division multiplexed. Transducers 502A to 502D (e.g., one of which can correspond to transducer 314) can generate transmit waveforms and receive reflections to determine the location / position of a touch on a surface (e.g., cover glass 312), as described with reference to timing diagram 560 during the acoustic touch sensing phase. Transducer 602 (e.g., corresponding to transducer 314) can generate transmit waveforms and receive reflections to determine the amount of force applied to the surface (e.g., cover glass 312), as described with reference to timing diagram 640 during the acoustic force sensing phase.

[0068] In some examples, acoustic touch and force sensing can be performed using simultaneously generated transmit waveforms. Figure 7 A timing diagram 700 for acoustic touch and force sensing according to an example of the present disclosure is shown. Signal 702 may correspond to a transmit waveform generated by a transducer (e.g., transducer 314) to propagate simultaneously in deformable material 316 and cover glass 312. Signal 704 may correspond to a reflection (e.g., a first reflection) from the boundary between deformable material 316 and rigid material 318. Signal 706 may correspond to a reflection from an object (e.g., a finger) on the surface of cover glass 312. Signal 708 may correspond to a reflection from the opposite edge of cover glass 312. Based on the timing of signal 704, the acoustic touch and force sensing circuitry may measure the time of flight through the deformable material. Based on the timing of signals 706 and / or 708, the acoustic touch and force sensing circuitry may measure the time of flight along the surface of cover glass 312 to the object (or edge when no object is contacting the cover glass). The time of flight measurement of the touch may be repeated (e.g., four times) for each transducer 502A-502D to determine the orientation / position of the object. The time-of-flight measurement can optionally be repeated (e.g., for each transducer 502A to 502D) to measure the force applied to the cover glass 312. In some examples, an average force measurement can be determined from the repeated force measurements. In some examples, the repeated measurements can indicate the relative forces applied to different edges of the cover glass. In some examples, the measurements can be combined with the different edges of the cover glass to determine the applied force.

[0069] Using one or more shared transducers to perform acoustic touch and force sensing can provide touch and force information using a set of ultrasonic transducers (e.g., 502A to 502D) and a single sensing circuit (e.g., acoustic touch and / or force sensing circuit 400). As a result, the touch and force sensing system can potentially reduce size, complexity, and power consumption.

[0070] The performance of ultrasonic touch and force sensing using ultrasonic waves simultaneously transmitted into deformable material 316 and cover glass 312 may, in some examples, depend on the separation between the transmitted ultrasonic waves used for touch and for force. Figure 7 Signals 704 and 706 corresponding to force and touch reflection, respectively, are shown, which may be well separated in time (e.g., such that the force reflection reaches the dead zone of the touch reflection). In practice, the integration of acoustic touch and force sensing may subject each measurement (touch / force) to noise / interference from the other measurements (force / touch).

[0071] In some examples, interference between ultrasonic waves in the deformable material and the cover glass can be reduced or eliminated based on the design of the deformable material. For example, the deformable material can be selected to have ultrasonic attenuation properties above a threshold, so that the signal in the deformable material can be suppressed before being reflected from the cover glass. In some examples, the thickness of the deformable material can be selected to allow one or more reflections through the deformable material to be received before being reflected from the cover glass. In some examples, the reflections through the deformable material (e.g., the first, second, nth) can be selected so that the reflection of interest occurring between reflections from the cover glass can be received. In some examples, an absorbent material can be coupled to the deformable material to further suppress oscillations of the ultrasonic signal in the deformable material. In some examples (e.g., when force and touch ultrasonic waves do not overlap in time), more than one transducer (and in some cases all transducers) can transmit waves and receive reflections simultaneously to measure the applied force. Each transducer can then transmit waves and receive reflected waves sequentially for touch detection.

[0072] Processing the data from the acoustic touch and / or force detection scans may be performed by different processing circuits of the acoustic touch and / or force sensing system. Figure 4 As described, an electronic device can include acoustic touch and force sensing circuitry 400 and a processor SoC 430 (e.g., including a host processor 432 and an auxiliary processor / sub-processor 434). As described in detail below, according to various examples, processing of touch and / or force data can be performed by one or more of these processors / circuits. For example, according to various examples, processing of touch and / or force data can be performed by the acoustic touch and force sensing circuitry, by the processor SoC, or partially by the acoustic touch and force sensing circuitry and partially by the processor SoC. The following description of data processing first addresses touch data processing and then addresses force data processing.

[0073] As described in more detail below, in some examples, the raw touch sensing data can be transmitted to the processor SoC for processing by one or more processors of the processor SoC (e.g., host processor 432 and auxiliary processor / sub-processor 434). In some examples, the touch sensing data can be processed in part by analog processing circuitry of an acoustic touch (and / or force) sensing circuit (e.g., as described above with reference to FIG). Figure 4 The touch sensing data may be processed by an acoustic touch (and / or force) sensing circuit (e.g., averaging of ADC outputs). Partially processed touch sensing data may be transmitted to a processor SoC for further processing. In some examples, acoustic touch (and / or force) sensing circuitry may process the touch sensing data and supply high-level touch information (e.g., the centroid of the touch) to the processor SoC. Acoustic touch and force sensing circuitry may be referred to as acoustic touch sensing circuitry to simplify the following description of touch data processing in various processors and circuits.

[0074] In some examples, the auxiliary processor (e.g., auxiliary processor 434) can be a low-power processor that can remain active even when the host processor (e.g., host processor 432) is idle and / or powered off. The acoustic touch sensing circuit (e.g., corresponding to the acoustic touch and force sensing circuit 400) can perform an acoustic touch sensing scan and generate acoustic touch data. The acoustic touch data can be transmitted to the auxiliary processor to be processed according to one or more touch sensing algorithms. For example, in the low-power mode, the acoustic touch sensing circuit can perform a low-power touch detection scan. The low-power touch detection scan can include receiving a signal from a transducer connected to one or more transducers (e.g., from a transducer other than the transducer). Figure 5A The system may be operable to detect reflections from a barrier (e.g., a surface edge) relative to one or more of the transducers (e.g., transducers other than the four transducers shown). Acoustic touch data corresponding to the received reflections from the one or more barriers may be transmitted to an auxiliary processor via a communication channel and processed by the auxiliary processor to determine the presence or absence of an object contacting the sensing surface. Once an object touching the sensing surface is detected, the system may transition from a low power mode to an active mode, and the acoustic touch sensing circuitry may perform an active mode touch detection scan. Additionally or alternatively, in some examples, a low power detection scheme (e.g., performed using one transducer) may be used in the low power mode. The active mode touch detection scan may include, for example, scanning the sensing surface, as described above with reference to Figure 5A As described above. Acoustic touch data corresponding to the active mode touch detection scan can be transmitted to the auxiliary processor via a communication channel and processed by the auxiliary processor to determine the location of the object. In some examples, determining the location of the object can include determining the area and / or centroid of the object. The host processor can receive the location of the object touching the surface from the auxiliary processor and perform an action based thereon.

[0075] In some examples, the acoustic touch sensing circuitry can perform some processing before sending the acoustic touch data to the auxiliary processor. For example, to reduce the requirements of the data communication channel between the acoustic touch sensing circuitry and the auxiliary processor, the acoustic touch sensing circuitry can include a digital signal processor that can average samples from the ADC output. Averaging the samples can reduce the amount of acoustic touch data to be transmitted to the auxiliary processor. The averaging performed by the digital signal processor can be controlled by control circuitry in the acoustic touch sensing circuitry (e.g., acoustic scan control logic 422). In some examples, the transmit signal can be encoded to allow averaging without time loss. Although averaging is described, in other examples, other forms of processing can be applied to the acoustic touch data before transmission.

[0076] In some examples, the data communication channel between the acoustic touch sensing circuit and the auxiliary processor can be a serial bus such as a serial peripheral interface (SPI) bus. In addition, the communication channel can also be bidirectional so that information (e.g., register information for programming the acoustic touch sensing circuit) can also be transmitted from the auxiliary processor to the acoustic touch sensing circuit. In addition, the acoustic touch sensing circuit can receive one or more synchronization signals from the auxiliary processor, wherein the auxiliary processor is configured to synchronize acoustic touch sensing scanning operations performed by the acoustic touch sensing circuit. In addition, the acoustic touch sensing circuit can generate an interrupt signal that is configured to provide appropriate acoustic data transmission from the acoustic touch sensing circuit to the auxiliary processor. In some examples, the detection and processing of the low-power touch detection mode can be completed on-chip (e.g., by the acoustic touch sensing circuit). In these examples, when a finger is detected on the surface of the device, an interrupt signal can be used to indicate this (e.g., to the auxiliary processor).

[0077] In some examples, the acoustic touch sensing circuitry may perform an acoustic touch sensing scan and generate acoustic touch data. The acoustic touch data may be transmitted to an auxiliary processor and / or a host processor for processing according to one or more touch sensing algorithms. For example, in low-power mode, the acoustic touch sensing circuitry may perform a low-power detection scan as described herein. The acoustic touch data may be transmitted to the auxiliary processor via a communication channel and processed by the auxiliary processor to determine whether an object is contacting the sensing surface. Once an object is detected contacting the sensing surface, the system may transition from low-power mode to active mode, and the acoustic touch sensing circuitry may perform an active mode detection scan as described herein. The acoustic touch data corresponding to the active mode detection scan may be transmitted to the host processor via a high-speed communication channel and processed by the host processor to determine the location of the object. In some examples, the data transmitted via the high-speed communication channel may be performed in burst mode. In some examples, determining the location of the object may include determining the area and / or centroid of the object. The host processor may perform operations based on the location.

[0078] In some examples, a high-speed communication channel can provide sufficient bandwidth to transmit raw acoustic touch data to a host processor without requiring processing by the acoustic touch sensing circuitry. In some examples, the high-speed communication channel can include circuitry (e.g., a serializer) that serializes the acoustic touch data and transmits the serialized acoustic touch data using low-voltage differential signaling (LVDS) communication circuitry. In some examples, the data can be transmitted using an I / O block. In some examples, the acoustic touch sensing circuitry can perform some processing (e.g., averaging) before sending the acoustic touch data to the host processor. In some examples, the amount of data generated by a low-power detection scan can be relatively small (compared to an active mode detection scan), allowing the raw acoustic touch data to be transmitted to the auxiliary processor without requiring processing by the acoustic touch sensing circuitry. In some examples, the acoustic touch sensing circuitry can perform some processing (e.g., averaging) before sending the acoustic touch data to the host processor. Other aspects of the operation (e.g., data transmitted from the auxiliary processor to the acoustic touch sensing circuitry, synchronization signals, interrupt signals, etc.) can be the same or similar to those described above. Although described above as processing acoustic touch data from a low-power detection scan in a secondary processor and processing acoustic touch data from an active mode detection scan in a host processor, it should be understood that in some examples the host processor may perform processing for both the low-power detection scan and the active mode detection scan.

[0079] In some examples, the acoustic touch sensing circuitry may include an acoustic touch digital signal processor (DSP). In some examples, the acoustic touch DSP may be a standalone chip coupled between the acoustic touch sensing circuitry and the processor SoC. The acoustic touch sensing circuitry may perform an acoustic touch sensing scan and generate acoustic touch data. The acoustic touch data may be transmitted to the acoustic touch DSP for processing according to one or more touch sensing algorithms. For example, in low-power mode, the acoustic touch sensing circuitry may perform a low-power detection scan as described herein. The acoustic touch data may be transmitted to the acoustic touch DSP via a communication channel and processed by the acoustic touch DSP to determine whether an object is contacting the sensing surface. In some examples, the acoustic touch sensing circuitry may process the acoustic touch data to determine whether an object is contacting the surface. Once an object is detected contacting the sensing surface, the system may transition from low-power mode to active mode, and the acoustic touch sensing circuitry may perform an active mode detection scan as described herein. The acoustic touch data corresponding to the active mode detection scan may be transmitted to the acoustic touch DSP via a high-speed communication channel and processed by the acoustic touch DSP to determine the location of the object. In some examples, determining the location of the object may include determining the area and / or centroid of the object. The location may be communicated to the auxiliary processor and / or the host processor, and the auxiliary processor and / or the host processor may perform an action based on the location.

[0080] In some examples, a high-speed communication channel can provide sufficient bandwidth to transmit raw acoustic touch data to the acoustic touch DSP without requiring processing by the acoustic touch sensing circuitry. In some examples, the high-speed communication channel can include circuitry (e.g., a CMOS serializer) that serializes the acoustic touch data and transmits the serialized acoustic touch data using low-voltage differential signaling (LVDS) communication circuitry. In some examples, the acoustic touch sensing circuitry can perform some processing (e.g., averaging) before sending the acoustic touch data to the acoustic touch DSP. In some examples, the amount of data generated by a low-power detection scan can be relatively small (compared to an active mode detection scan), allowing the raw acoustic touch data to be transmitted to the acoustic touch DSP without requiring processing by the acoustic touch sensing circuitry. In some examples, data from the low-power detection scan can also be transmitted to the acoustic touch DSP via the high-speed communication channel.

[0081] The data, synchronization signals, and interrupt signals transmitted from the auxiliary processor to the acoustic touch sensing circuitry can be the same or similar to those described above, except that, in some examples, the various signals and data can pass through the acoustic touch DSP.

[0082] In some examples, the acoustic touch sensing circuitry may perform an acoustic touch sensing scan and generate acoustic touch data. The acoustic touch data (e.g., for a low-power detection scan) may be processed by the acoustic touch sensing circuitry to determine whether an object is in contact with the surface. Once an object is detected contacting the sensing surface, the system may transition from a low-power mode to an active mode, and the acoustic touch sensing circuitry may perform an active mode detection scan as described herein. The acoustic touch data corresponding to the active mode detection scan may be processed by the acoustic touch sensing circuitry to determine the location of the object. In some examples, determining the location of the object may include determining an area and / or centroid of the object. The presence and / or location of the object may be communicated to an auxiliary processor and / or a host processor, and the auxiliary processor and / or the host processor may perform an action based on the presence and / or location of the object.

[0083] In some examples, the amount of post-processed information (e.g., center of gravity) can be relatively small (compared to the raw acoustic touch data), such that the information can be transmitted to an auxiliary processor and / or host processor via a serial communication bus (e.g., SPI) without requiring a high-speed data channel.

[0084] The data, synchronization signals, and interrupt signals transmitted from the auxiliary processor to the acoustic touch sensing circuit can be the same or similar to those described above. In some examples, separate data communication channels can be provided between the acoustic touch sensing circuit and each of the auxiliary processor and the host processor. In some examples, the data communication channel can be a shared bus (e.g., a shared SPI bus) between the acoustic touch sensing circuit and each of the auxiliary processor and the host processor.

[0085] As described herein, the acoustic touch sensing circuitry can be turned off or placed in a low-power state when not in use. In some examples, the acoustic touch sensing circuitry can be turned on only during acoustic touch detection scans (e.g., during Tx and Rx operations). In some examples, the acoustic touch sensing circuitry can be in a low-power state at all times (e.g., running at a low frame rate, performing low-power detection scans), and can transition to an active mode state when an object is detected.

[0086] In a similar manner, processing of force data may be performed by different processing circuits of the acoustic touch and / or force sensing system. Figure 4 As described, the electronic device may include acoustic touch and force sensing circuit 400 and processor SoC 430 (e.g., including host processor 432 and auxiliary processor / sub-processor 434). In some examples, force detection circuit 424 may be repeated (or reused) Figure 4touch sensing circuitry to collect and / or process force data. In some examples, the raw force sensing data may be transmitted to the processor SoC via the force detection circuit 424 for processing by one or more processors of the processor SoC (e.g., the host processor 432 and the auxiliary processor / sub-processor 434). In some examples, the force sensing data may be partially processed by analog processing circuitry and / or digital processing circuitry of the acoustic force (and / or touch) sensing circuitry. The partially processed force sensing data may be transmitted to the processor SoC for further processing. In some examples, the acoustic force (and / or touch) sensing circuitry may process the force sensing data and provide force information (e.g., the amount of force applied) to the processor SoC. In addition, in addition to or as an alternative to the low-power touch detection scan described above, a low-power detection scan may also be used (e.g., to cause the device to exit a low-power or idle mode). The low-power force detection scan may include, for example, determining the force applied to the surface using fewer than all transducers (e.g., one transducer).

[0087] In some examples, force detection circuitry 424 can be simplified relative to touch detection circuitry to reduce power and hardware requirements. Figures 8A to 8C An exemplary circuit for force detection according to an example of the present disclosure is shown. It should be understood that Figures 8A to 8C The circuits are exemplary and other circuits may be used for force sensing. Figures 8A to 8C The circuit can be single-ended, but partially or fully differential circuits can also be used. Figure 8AAn exemplary force detection circuit 800 according to an example of the present disclosure is shown. Force detection circuit 800 may include a gate (or switch) 801, a programmable gain amplifier (PGA) 802, an analog comparator 804, a time-to-digital signal converter 806, and optionally, a digital comparator 808. A gate timing signal may be used to activate (e.g., close a switch) gate 801 between the input of a transducer used to measure force and PGA 802. The gate timing signal may also be used to initiate timing by time-to-digital signal converter 806. The output of PGA 802 may be input to comparator 804, which may be used to detect a reliable transition edge in the received signal. When the comparator transitions, timing by time-to-digital signal converter 806 is stopped. The digital output (e.g., a digitized number) of time-to-digital signal converter 806, which may be proportional to the applied force, may be sent from the acoustic force (and / or touch) sensing circuit to a processor. In some examples, the optional digital comparator 808 may be used to transmit a force reading that exceeds a threshold value. In some examples, a time window can be selected, and all or some of the threshold spanning timestamps can be sent from the acoustic force (and / or touch) sensing circuitry to the processor SoC, and the timestamps can be used to detect changes in time of flight (and therefore applied force). In some examples, digitized data for a given time window can be sampled at two different times (one with no force applied and one with force applied), and a correlation between the two time of flight measurements can be used to determine changes in time of flight (and therefore applied force).

[0088] Figure 8B An exemplary force detection circuit 810 according to an example of the present disclosure is shown. Force detection circuit 810 may include a gate (or switch) 811, a PGA 812, a differential-to-single-ended converter circuit 812, an analog comparator 814, a logic AND gate 816, a digital counter 818, and a clock 820. A gate timing signal may be used to activate (e.g., close a switch) gate 811 between the input of a transducer used to measure force and the differential-to-single-ended converter circuit 812. The single-ended output of the differential-to-single-ended converter circuit 812 may be provided to PGA 812. The gate timing signal may also be output to logic AND gate 816. When both the gate timing signal and the output of analog comparator 814 are high, counter 818 may begin timing based on a clock signal from clock 820. The output of PGA 812 may be input to comparator 814, which may be used to detect a reliable transition edge in the received signal. When the comparator transitions, timing of counter 818 may be stopped. A digital output (eg, a digitized number) from the counter 818 , which may be proportional to the applied force, may be sent from the acoustic force (and / or touch) sensing circuit to the processor.

[0089] It should be understood that the exemplary force detection circuits 800 and 810 can be reconfigured to output a threshold crossing upon a rising edge, a falling edge, or both of the received signal. Figure 8A and Figure 8B The force detection circuits 800 and 810 shown in FIG output a rising edge threshold after each rising edge of the time gate signal. In some examples, a threshold crossing may be detected at both a rising edge and a falling edge of the input signal. Figure 8C An exemplary force detection circuit 830 according to an example of the present disclosure is shown. Force detection circuit 830 may include a gate (or switch) 831, a PGA 832, an analog comparator 834, a logic inverter 836, n-bit D flip-flops 838 and 840, a clock 842, and a digital counter 844. A reset signal may be used to reset D flip-flops 838 and 840. A time window signal may be used to activate gate 831 between the input of the transducer used to measure force and PGA 832. The time window signal may also enable counter 844 to begin timing based on a clock signal from clock 842. The output of PGA 832 may be input to comparator 834, which may be used to detect a reliable transition edge of the received signal. The output of comparator 834 may be used to clock D flip-flops 838 and 840. D flip-flop 838 may be clocked with an inverted version of the comparator output to detect opposing edges. D flip-flops 838 and 840 can each receive the output of counter 844 as a data input and output the count of counter 844 for counting rising and falling edge transitions. The digital outputs (e.g., digitized numbers) of D flip-flops 838 and 840, which can be proportional to the applied force, can be sent from the acoustic force (and / or touch) sensing circuit to a processor.

[0090] As described above, in some examples, force data may be sampled at two different times (once with no force applied and once with force applied), and the correlation between the two time-of-flight measurements may be used to determine the change in time of flight (and therefore the applied force). Figure 9 Exemplary configurations of acoustic touch and / or force sensing circuitry according to examples of the present disclosure are shown. Figure 9 The circuit shown corresponds to Figure 4 The example shown implements a corresponding circuit for detecting force. Figure 4 different, Figure 9 The acoustic touch and / or force sensing circuitry may include a correlator 950. The correlator 950 may be a digital correlator configured to correlate force data for a no-force condition (e.g., a baseline) with force data that may include a measurement of applied force. The correlation may indicate a change in the time of flight (or resonance) in the deformable material, thereby indicating an applied force.

[0091] As described above, the acoustic touch and force sensing scans performed by the acoustic touch and force sensing circuitry may involve stimulating and sensing one or more transducers. Figures 10A to 10EAn exemplary integration of acoustic touch and force sensing circuitry and / or one or more processors (e.g., a processor SoC) according to examples of the present disclosure is shown, wherein the transducer is mechanically and acoustically coupled to a surface (e.g., glass, plastic, metal, etc.) and / or a deformable material (e.g., silicone, rubber, etc.). Figure 10A An exemplary acoustic touch and force sensing system configuration 1000 is shown using four acoustic transducers 1004A to 1004D mounted (or otherwise coupled to) along four edges of a surface 1002 (e.g., the underside of a cover glass). The transducers 1004A to 1004D can be configured to generate acoustic waves (e.g., shear horizontal waves) and receive reflected acoustic waves. Additionally, the acoustic transducers 1004A to 1004D can also be mounted on (or otherwise coupled to) a deformable material (e.g., a gasket) disposed between the surface 1002 and a rigid material (e.g., a portion of a housing). One or more acoustic touch and force sensing circuits can be included. For example, Figure 10A A first acoustic touch and force sensing circuit 1006 is shown positioned adjacent to adjacent edges of transducers 1004C and 1004D. Similarly, a second acoustic touch and force sensing circuit 1006' can be positioned adjacent to adjacent edges of transducers 1004A and 1004B. The placement of the acoustic touch and force sensing circuits as shown can reduce routing between transducers 1004A through 1004D and the corresponding acoustic touch and force sensing circuits. Processor SoC 1008 can be coupled to one or more acoustic touch and force sensing circuits to perform various processes as described herein. In some examples, some or all of the driver circuitry (Tx circuitry) and / or some or all of the receiver circuitry (Rx circuitry) of the touch and force sensing circuitry can be implemented on different silicon chips.

[0092] In some examples, transducers 1004A- 1004D may be coupled to one or more acoustic touch and force sensing circuits via a flexible circuit (eg, a flexible printed circuit board). Figure 10B Shown along Figure 10A FIG1010 is a diagram of an exemplary acoustic touch and force sensing system configuration 1000, captured from FIG1010 in FIG1010 . Figure 10BAs shown, transducer 1004D can be coupled to surface 1002 by bonding between a bonding material layer 1014 on the underside of surface 1002 and a first signal metal layer 1012A on one side of transducer 1004D. In some examples, bonding material layer 1014 can be conductive (e.g., a metal layer). In some examples, bonding material layer 1014 can be non-conductive. The first signal metal layer 1012A on one side of transducer 1004D and the second signal metal layer 1012B on the second side of transducer 1004D can provide two terminals of transducer 1004D to which an excitation signal can be applied and through which a reflection can be received. The first signal metal layer 1012A wraps around the transducer from one side of transducer 1004D to the opposite side so that the two signal metal layers of transducer 1004D are bonded to one side of transducer 1004D. Figure 10B , acoustic touch and force sensing circuit 1006 can be coupled to flex circuit 1016, and the flex circuit can be bonded (e.g., via bond 1018) to signal metal layers 1012A and 1012B, respectively, of transducer 1004D. Similarly, transducer 1004C can be coupled to surface 1002 (e.g., via a bonding metal layer / first signal metal layer bond) and acoustic touch and force sensing circuit 1006 by bonding the flex circuit to the signal metal layer on the side of the transducer opposite the surface. Similarly, transducers 1004A and 1004B can be coupled to surface 1002 and second acoustic touch and force sensing circuit 1006′.

[0093] Transducers 1004A to 1004D may also be coupled to the deformable material 1003. For example, the deformable material 1003 may be a gasket disposed between the surface 1002 and the rigid material 1007. When assembled, the deformable material 1003 (e.g., the gasket) may form a watertight seal between the surface 1002 (e.g., the cover glass) and the rigid material 1007 (e.g., the housing). The transducers 1004A to 1004D in contact with the deformable material 1003 may apply an excitation signal to the deformable material 1007 and receive a reflection from the deformable material. In a similar manner, the transducers 1004A to 1004D may also be coupled to, for example, a surface 1002 and a rigid material 1007. Figures 10C to 10E Deformable material 1003 is shown.

[0094] In some examples, transducers 1004A- 1004D can be coupled to the acoustic touch and force sensing circuitry via an interposer (eg, a rigid printed circuit board). Figure 10C FIG1020 shows an exemplary acoustic touch and force sensing system configuration 1000 taken along view AA. Transducers 1004C and 1004D may be coupled to surface 1002, such as in conjunction with FIG1020 . Figure 10B shown and described. However, in Figure 10C1004D (e.g., via bond 1024), rather than bonding acoustic touch and force sensing circuit 1006 to flex circuit 1016 and flex circuit 1016 to signal metal layers 1012A and 1012B of transducer 1004D. Acoustic touch and force sensing circuit 1006 may be bonded or otherwise coupled to interposer 1022. Similarly, transducers 1004A and 1004B may be coupled to surface 1002 and second acoustic touch and force sensing circuit 1006'. In some examples, transducers 1004A through 1004D may be bonded directly to the acoustic touch and force sensing circuit. Figure 10D FIG1030 shows an exemplary acoustic touch and force sensing system configuration 1000 taken along view AA. Transducers 1004C and 1004D may be coupled to surface 1002, such as in conjunction with FIG1030 . Figure 10B shown and described. However, in Figure 10D 1004D, instead of bonding acoustic touch and force sensing circuit 1006 to a flex circuit or interposer, and bonding the flex circuit / interposer to signal metal layers 1012A and 1012B of transducer 1004D, acoustic touch and force sensing circuit 1006 may be bonded to signal metal layers 1012A and 1012B of transducer 1004D (e.g., via bond 1032). Similarly, transducers 1004A and 1004B may be coupled to surface 1002 and a second acoustic touch and force sensing circuit 1006′.

[0095] exist FIG. 10B to FIG. 10D , signal metal layer 1012A is routed away from surface 1002, and both signal metal layers 1012A and 1012B are bonded to the acoustic touch and force sensing circuitry via bonding (e.g., via a flex circuit, an interposer, or direct bonding) on ​​a side of transducer 1004D that is separate from surface 1002. In some examples, the acoustic touch and force sensing circuitry can be bonded to routing on surface 1002. Figure 10E A view 1040 of an exemplary acoustic touch and force sensing system configuration 1000 is shown, taken along view AA. Figure 10ADifferently, for example, transducer 1004D can be coupled to surface 1002 via two separate portions of metallic bonding layers. A first portion of metallic bonding layer 1042A can be bonded to first signal metal layer 1044A (using a metal-to-metal conductive bond), and a second portion of metallic bonding layer 1042B can be bonded to second signal metal layer 1044B (which can optionally be wrapped around transducer 1004D). Although not shown, the first and second portions of metallic bonding layers 1042A and 1042B can be routed along the underside of surface 1002 and can be bonded to or bonded to a flexible circuit or interposer including acoustic touch and force sensing circuitry. Similarly, transducer 1004C can be coupled to surface 1002 and acoustic touch and force sensing circuitry 1006 via on-surface routing. Similarly, transducers 1004A and 1004B can be coupled to surface 1002 via on-surface routing and to second acoustic touch and force sensing circuit 1006'. FIG. 10B to FIG. 10D , Figure 10E One advantage of the integration shown is that the deformable material 1003 can have a more uniform shape around the perimeter of the device. FIG. 10B to FIG. 10D As shown, the deformable material may include cutouts or notches, or have different properties (e.g., different thicknesses) at the location of the acoustic touch and force sensing circuitry (and / or the flex circuit or interposer). Alternatively, the transducer may be made thinner in the electrical connection area to accommodate FIG. 10B to FIG. 10D In some examples, a push-pull force sensing may be used. In such examples, a receiving transducer may be added between the deformable material 1003 and the rigid material 1007 (e.g., as shown in FIG6 ).

[0096] It should be understood that the integration of acoustic touch and force sensing circuitry, transducers, and surfaces described herein is exemplary, and many other techniques may be used. The transducers may be attached to the edge of the cover glass (e.g., on one side of the cover glass) or underneath the cover glass. In some examples, the transducers may be integrated into a recess in the cover glass. In all integrations of the transducer and cover glass, the attachment and bonding should be performed in a manner that allows the desired acoustic waves to be generated and propagated in the cover glass (or on top of the cover glass). In some examples, matching or backing materials may be added to the transducers to improve their performance and improve matching with the target surface medium (e.g., the cover glass). Similarly, matching or backing materials may be added to the transducers that are bonded to the deformable material 1003 to improve the performance of force detection and matching with the deformable material medium. In some examples, the transducers for touch detection may be implemented on the edge of the cover glass, and the transducers for force detection may be implemented on the corners of the cover glass.

[0097] As described above, in some examples, the transmitter and receiver functions can be separated so that the transmission of acoustic energy at 302 and the reception of acoustic energy at 304 may not occur at the same transducer. In some examples, the transmitting transducer and the receiving transducer can be made of different materials to maximize the transmission and reception efficiency, respectively. In some examples, having separate transmitting and receiving transducers can allow high-voltage transmitting circuits and low-voltage receiving circuits to be separated (for touch and / or force sensing circuits). Figure 11 1 shows an exemplary configuration of an acoustic touch and force sensing circuit 1100 according to an example of the present disclosure. Figure 11 Configuration, Figure 4 The configuration may include acoustic touch and force sensing circuit 1100 and processor SoC 1130. As described above, processor SoC 1130 may include host processor 1132 (eg, corresponding to processor 432) and auxiliary processor 1134 (corresponding to auxiliary processor 434). Similarly, acoustic touch and force sensing circuit 1100 may include: transmitter 1102 (corresponding to transmitter 402), transmit switching circuit 1104A (corresponding to the demultiplexer of switching circuit 404), receive switching circuit 1104B (e.g., corresponding to the multiplexer of switching circuit 404), amplifier 1110 (e.g., corresponding to amplifier 410), gain and offset correction circuit 1112 (e.g., corresponding to gain and offset correction circuit 412), demodulation circuit, envelope detection circuit and / or filters 1114 to 1116 (e.g., corresponding to demodulation circuit 414, envelope detection circuit 415 and / or filter 416), ADC 1118 (e.g., corresponding to ADC 418), and I / O circuit 1120 (e.g., corresponding to I / O circuit 420). Acoustic touch and force sensing circuit 1100 may also include force detection circuit 1124 (e.g., corresponding to force detection circuit 424). The operation of these components may be similar to the above with respect to Figure 4 and for the sake of brevity, the details will be omitted here. Figure 4 different, Figure 11 The configuration shown may include a transducer 1106A operating as a transmitter and a separate transducer 1106B operating as a receiver. Transducers 1106A and 1106B may be co-located in the previously described transmitting and receiving transducer locations. For example, transducer 502A may be replaced by a first transducer configured for transmitting and a second transducer configured for receiving.

[0098] It should be understood that Figure 11 The configuration is not limited to Figure 11 Rather, the components and configurations may include other components or additional components in a variety of configurations according to various examples. Figure 11Some or all of the components shown may be included in a single circuit, or may be distributed across multiple circuits while remaining within the scope of the examples disclosed herein. In some examples, some or all of transmit circuitry 1102 and transmit switching circuitry 1104A may be implemented in one chip, and some or all of receive circuitry 408 and receive switching circuitry 404B may be implemented in another chip. A first chip including transmit circuitry may receive and / or generate a high voltage power supply for energizing the surface via a voltage boost circuit. A second chip including receive circuitry may operate without receiving or generating a high voltage power supply. In some examples, more than two chips may be used, and each chip may house a portion of transmit circuitry and / or receive circuitry.

[0099] 12A to 12E An exemplary integration of acoustic touch and force sensing circuitry and / or one or more processors (e.g., a processor SoC) according to examples of the present disclosure is shown, wherein a transducer group (e.g., one for transmitting and one for receiving) is mechanically and acoustically coupled to a surface (e.g., glass, plastic, metal, etc.) and / or a deformable material (e.g., silicone, rubber, etc.). Figure 12A An exemplary acoustic touch and force sensing system configuration 1200 is shown using eight acoustic transducers, including four transmitting transducers 1204A to 1204D mounted along four edges of a surface 1202 (e.g., cover glass), and four receiving transducers 1205A to 1205D. The transmitting transducers 1204A to 1204D can be configured to generate acoustic waves (e.g., horizontal shear waves), and the receiving transducers 1205A to 1205D can be configured to receive reflected acoustic waves. Additionally, the acoustic transducers 1204A to 1204D and 1205A to 1205D can also be mounted on (or otherwise coupled to) a deformable material (e.g., a gasket) disposed between the surface 1002 and a rigid material (e.g., a portion of a housing). One or more acoustic touch and force sensing circuits can be included. For example, Figure 12A A first acoustic touch and force sensing circuit 1206 is shown positioned adjacent to adjacent edges of transmitting transducers 1204C-1204D and receiving transducers 1205C-1205D. Similarly, a second acoustic touch and force sensing circuit 1206' can be positioned adjacent to adjacent edges of transmitting transducers 1204A-1204B. The acoustic touch and force sensing circuits shown can reduce routing between transducers and corresponding acoustic touch and force sensing circuits. Processor SoC 1208 can be coupled to one or more acoustic touch and force sensing circuits.

[0100] In some examples, transducers 1204A-D / 1205A-D may be coupled to the acoustic touch and force sensing circuitry via a flexible circuit (eg, a flexible printed circuit board). Figure 12B Shown along Figure 12A FIG1210 is a diagram of an exemplary acoustic touch and force sensing system configuration 1200 captured from view AA of FIG1210. Figure 12B As shown, the receiving transducer 1205D can be coupled to the surface 1202 by bonding between an adhesive material layer 1214 on the underside of the surface 1202 and a first signal metal layer 1212A on one side of the receiving transducer 1205D. In some examples, the adhesive material layer 1214 can be conductive (e.g., a metal layer). In some examples, the adhesive material layer 1214 can be non-conductive. The first signal metal layer 1212A on one side of the receiving transducer 1205D and the second signal metal layer 1212B on the second side of the receiving transducer 1205D can provide two terminals of the receiving transducer 1205D from which reflections can be received. The first signal metal layer 1212A wraps around the transducer from one side of the receiving transducer 1205D to the opposite side so that the two signal metal layers of the receiving transducer 1205D are bonded to one side of the receiving transducer 1205D. Figure 12B , acoustic touch and force sensing circuit 1206 can be coupled to flexible circuit 1216, and the flexible circuit can be bonded to signal metal layers 1212A and 1212B, respectively, of receiving transducer 1205D (e.g., via bonding member 1218). Similarly, transmitting circuit 1204D (not shown) can be coupled to surface 1202 and can provide two terminals to which stimulation signals can be applied. The flexible circuit can be bonded to the corresponding signal metal layers of transmitting transducer 1204D. Similarly, transmitting transducer 1204C and receiving transducer 1204D can be coupled to surface 1202 (e.g., via bonding metal layer / first signal metal layer bonding member) and acoustic touch and force sensing circuit 1206 by bonding the flexible circuit to the signal metal layer on the transducer side opposite the surface. Similarly, transmitting transducers 1204A-B and receiving transducers 1205A-B can be coupled to surface 1202 and second acoustic touch and force sensing circuit 1206′.

[0101] Transducers 1204A-D and 1205A-D may also be coupled to the deformable material 1203. For example, the deformable material 1203 may be a gasket disposed between the surface 1202 and the rigid material 1207. When assembled, the deformable material 1203 (e.g., the gasket) may form a watertight seal between the surface 1202 (e.g., the cover glass) and the rigid material 1207 (e.g., the housing). The transducers 1204A-D and 1205A-D in contact with the deformable material 1203 may apply an excitation signal to the deformable material 1207 and receive a reflection from the deformable material. In a similar manner, the transducers 1204A-D and / or 1205A-D may also be coupled to, for example, a surface 1202 and a rigid material 1207. 12C to 12E Deformable material 1203 is shown.

[0102] In some examples, transmitting transducers 1204A-D and receiving transducers 1205A-D can be coupled to the acoustic touch and force sensing circuitry via an interposer (eg, a rigid printed circuit board). Figure 12C FIG1220 shows an exemplary acoustic touch and force sensing system configuration 1200 taken along view AA. Transmitting transducers 1204C-D and receiving transducers 1205C-D can be coupled to surface 1202, as shown in FIG1220 . Figure 12B shown and described. However, in Figure 12C 1205D, and the flex circuit is bonded to the signal metal layers 1212A and 1212B of the receiving transducer 1205D. In the embodiment shown in FIG. 1205D, instead of bonding the acoustic touch and force sensing circuit 1206 to the flex circuit 1216, and the flex circuit to the signal metal layers 1212A and 1212B of the receiving transducer 1205D, the interposer 1222 can be bonded (e.g., via bonding 1224) to the signal metal layers 1212A and 1212B of the receiving transducer 1205D. The acoustic touch and force sensing circuit 1206 can be bonded or otherwise coupled to the interposer 1222. Similarly, the remaining transducers (transmit and receive) can be coupled to the surface 1202 and the first or second acoustic touch and force sensing circuits 1206 and 1206′.

[0103] In some examples, transmitting transducers 1204A-D and receiving transducers 1205A-D can be bonded directly to the acoustic touch and force sensing circuitry. Figure 12D FIG1230 shows an exemplary acoustic touch and force sensing system configuration 1200 taken along view AA. Transmitting transducers 1204C-D and receiving transducers 1205C-D can be coupled to surface 1202, as shown in FIG1230 . Figure 12B shown and described. However, in Figure 12D 1205D, instead of coupling acoustic touch and force sensing circuit 1206 to a flex circuit or interposer, and bonding the flex circuit / interposer to signal metal layers 1212A and 1212B of receiving transducer 1205D, acoustic touch and force sensing circuit 1206 may be bonded to signal metal layers 1212A and 1212B of receiving transducer 1205D (e.g., via bonding member 1232). Similarly, the remaining transducers (transmit and receive) may be coupled to surface 1202 and first or second acoustic touch and force sensing circuits 1206 and 1206'.

[0104] exist 12B to 12D In FIG, signal metal layer 1212A is routed away from surface 1202, and both signal metal layers 1212A and 1212B are bonded to the acoustic touch and force sensing circuitry via a bond (e.g., via a flex circuit, an interposer, or direct bonding) on ​​a side of receiving transducer 1205D that is separate from surface 1202. In some examples, for example, the acoustic touch and force sensing circuitry may be bonded to routing on surface 1202 rather than to routing on surface 1202 similar to the embodiments described above with reference to FIG. Figure 10E Description.

[0105] Although Figure 12A The transmit transducers 1204A-D are shown side-by-side with the receive transducers 1205A-D, but in some examples, the transmit transducers 1204A-D and the receive transducers 1205A-D may be stacked on top of each other. Figure 12E A view 1240 of an exemplary acoustic touch and force sensing system configuration 1200 is shown, taken along view AA. Figure 12E As shown, receive transducer 1205D can be coupled to surface 1202 via bonding between bonding metal layer 1242 on the underside of surface 1202 and first signal metal layer 1246A on one side of receive transducer 1205D. Transmit transducer 1204D can be coupled to receive transducer 1205D via common second signal metal layer 1244 on a second side of receive transducer 1205D. First metal layer 1246B can be deposited on the second side of transmit transducer 1204D. First signal metal layer 1246A and common second signal metal layer 1244 can provide two terminals of receive transducer 1205D, from which reflections can be received. First signal metal layer 1246B and common second signal metal layer 1244 can provide two terminals of transmit transducer 1204D, to which a transmit wave can be applied. In some examples, the common signal metal layer can be a common ground for the transmit and receive transducers. In some examples, the metal connections for the transmit and receive transducers can be separated from each other, and differential or single-ended transmit and receive circuits can be used. Although not shown, the wiring of the signal metal layers 1244, 1246A, and 1246B can be positioned so that the acoustic touch and force sensing circuit 1206 can be connected to the wiring on the surface 1202 or exposed surface of the transmit transducer 1204D and / or receive transducer 1205D to enable the acoustic touch and force sensing circuit to be directly or indirectly bonded to the surface 1202 or to the transducers 1204D / 1205D. In some examples, the bonding metal 1242 can be bonded to the 1246A signal metal (using a metal-to-metal conductive bond). It should be noted that, compared to 12B to 12D Integration, Figure 12E One advantage of the integration shown may be that the deformable material 1003 may have a more uniform shape around the perimeter of the device. 12B to 12D As shown, the deformable material may include cutouts or have different properties (e.g., different thicknesses) in which the acoustic touch and force sensing circuitry (and / or flex circuit or interposer) is located.

[0106] Figure 13 1 through 19 illustrate various configurations for integrating touch and force sensing functionality within an electronic device. Figure 13Each of the embodiments shown in FIG. 19 includes a cover glass that may correspond to the cover glass 312 described above, a display stack, a housing that may correspond to the rigid material 318 described above, a transducer that may correspond to the transducer 314 described above, and a deformable material that may correspond to the deformable material 316 described above (e.g., as may be included in a force sensing stack). In some examples, the display stack may include a stack for touch sensing circuitry (e.g., capacitive touch sensing). Each of the different configurations can be used to build a device with touch sensing and force sensing capabilities, as will be described in more detail below.

[0107] Figure 13 A first exemplary configuration for integrating touch-sensing and force-sensing circuitry with a housing 1304 and cover glass 1302 of an electronic device is shown. In some examples, transducer 1308 can be coupled to one side of cover glass 1302. In some examples, cover glass 1302 can be disposed above display stackup 1306. In some examples, display stackup 1306 can include a touch sensor stackup, such as a capacitive touch sensor stackup. In some examples, transducer 1308 can have a height in the y-axis dimension that approximates the thickness of cover glass 1302 in the y-axis dimension. In some examples, this can allow transducer 1308 to generate uniform acoustic waves across the entire thickness of cover glass 1302. In some examples, by placing transducer 1308 on one side of the cover glass, stimulating the transducer with a voltage or current can generate horizontal shear waves, Rayleigh waves, Lamb waves, Love waves, Stoneley waves, or surface acoustic waves traveling in the x-axis direction in cover glass 1302. In some examples, more than one transducer 1304 can be positioned around the perimeter of the cover glass 1302 to provide touch measurements with two-dimensional coordinates on the cover glass surface (e.g., as described above with reference to transducers 502A-502D). The transducer 1308 can be disposed on a backing material 1310, which can in turn provide a mechanical connection between the transducer and the housing 1304. In some examples, an encapsulant 1316 can be provided to hide the transducer 1308 and backing material 1310 from the user and to provide additional mechanical stability. In some examples, the encapsulant 1316 can be part of the housing 1304, and in some examples, the encapsulant can be a different material than the housing (e.g., glass, zircon, titanium, sapphire, etc.). In some examples, the force sensor stack 1312 can be positioned behind the cover glass 1302 and can be operated to detect touch as described above in at least Figures 3 and 6 to 7. Figure 7 The force described in .

[0108] Figure 14A second exemplary configuration for integrating touch-sensing and force-sensing circuitry with a housing 1404 and cover glass 1402 of an electronic device is shown. Figure 14 Shown with Figure 13 A similar configuration is shown in which transducer 1408 is coupled to one side of cover glass 1402. In some examples, transducer 1408 can have a height in the y-axis dimension that can be close to the thickness of cover glass 1402 in the y-axis dimension. In some examples, by placing transducer 1408 on one side of the cover glass, stimulating the transducer with a voltage or current can generate horizontal shear waves that travel in the cover glass 1402 along the x-axis direction. In some examples, more than one transducer 1404 can be positioned around the periphery of cover glass 1402 to provide touch measurements with two-dimensional coordinates on the surface of the cover glass (e.g., as described above with reference to transducers 502A-502D). In some examples, each transducer 1408 can generate shear waves oriented in a different direction. In addition to encapsulant 1416 (which can correspond to encapsulant 1316 described above), a second encapsulant can be used to provide a mechanical base for cover glass 1402, transducer 1408, and backing material 1410. Including the second encapsulation 1418 can simplify the structure of the housing 1404 by requiring one less recess in the housing. In some examples, the force sensor stack 1412 can be supported directly by the housing 1404 and can be operated to detect the force sensor stack as described above in at least FIG. 3 and FIG. 6. Figure 7 The force described in .

[0109] Figure 15 A third exemplary configuration for integrating touch sensing and force sensing circuitry with a housing 1504 and curved cover glass 1502 of an electronic device is shown. Figure 13 and Figure 14 1504. In some examples, the transducer 1508 and backing material 1510 may be positioned within a recess or groove in the housing 1504, such as a recessed portion of the housing 1504. Figure 15 In some examples, the acoustic energy generated by the transducer 1508 can be directed along the curved edge 1502' of the cover glass and can continue to propagate along the surface to perform as described above with reference to Figure 25. In some examples, the gradual curvature of the cover glass 1502 can be used to guide waves along the curved edge 1502' of the cover glass toward the flat surface. The force sensor stack 1512 can be supported by the housing 1504, and the legs 1514 can be coupled to the cover glass 1502 to transmit the force applied to the cover glass to the touch detection device 1502 as described above at least in FIG. 3 and FIG. 6. Figure 7 Specifically, because the force sensor stackup 1512 can be located below the curved edge 1502' of the cover glass 1502, standoffs 1514 can be included to translate forces onto the flat force sensor stackup.

[0110] Figure 16 Shown Figure 15 10 , a force sensor stackup 1612 can be positioned below a curved edge 1602′ of the cover glass 1602, and standoffs 1614 can be coupled to the cover glass 1602 to transmit forces applied to the cover glass into the force sensor stackup.

[0111] Figure 17 A fourth exemplary configuration is shown for integrating touch sensing and force sensing circuitry with housing 1704 and cover glass 1702. Transducer 1708 can be disposed on backing material 1710 formed within a cavity behind cover glass 1702. The acoustic waves generated by stimulating transducer 1708 can approximate direct stimulation at one side of cover glass 1702, as shown in FIG. Figure 13 and Figure 14 As shown, while maintaining the curved edge 1702 covering the glass surface, as Figure 15 and Figure 16 In other words, the transducer 1708 can be used to generate a wave that travels in the x-axis direction along the flat surface of the cover glass 1702, without relying on directing the wave through the curved edge 1702' of the cover glass. The reflection of the emitted acoustic energy can be used for touch detection as described above (e.g., with reference to FIG. Figure 2 5). The force sensing stack 1712 may be disposed between the cover glass 1702 and the housing 1704 to perform the functions described above with respect to at least FIG. 3 and FIG. 6. Figure 7 Force sensing as described in.

[0112] Figure 18A fifth exemplary configuration for integrating touch sensing and force sensing circuitry with the housing 1804 and the cover glass 1802 is shown. In some examples, the transducer 1808 and the backing material 1810 can be disposed on the back side of the cover glass 1802. In some examples, acoustic energy from the transducer 1808 can begin propagating in the y-axis direction, can reflect from the curved edge 1802' of the cover glass 1802, and can travel in the x-axis direction as described in the examples above. In some examples, the amount of curvature of the curved edge 1802' can determine the dispersion of the reflected acoustic energy. In some examples, this dispersion can cause the reflected acoustic energy to be dispersed in the measured time of flight and can have an impact on touch detection, as described above Figure 2 5. The force sensor stack 1812 may be coupled to the housing 1804 to perform at least the functions described above with respect to FIG. 6 through FIG. Figure 7 Force sensing as described in.

[0113] Figure 19A and Figure 19B An exemplary configuration for integrating touch sensing and force sensing circuitry with shared elements with a housing 1904 and cover glass 1902 of an electronic device is shown. In some examples, Figure 19A and Figure 19B The diagram can be as above Figures 2 to 7 For a specific implementation of the integrated touch sensing and force sensing described in Figure 3B 、 Figure 5A 、 Figure 6A and Figure 6B . Figure 19A and Figure 19B There is a difference in the shape of the cover glass 1902. Figure 19A In FIG, the cover glass 1902 can have a flat back surface, and the transducer 1908 can be positioned directly on the back surface of the cover glass. Figure 19B In the example shown, the cover glass 1902 may have a downwardly extending portion at the edge of the cover glass, and the transducer 1908 may be disposed on the downwardly extending portion of the cover glass. In other examples, the transducer 1908 may be attached to a curved cover glass 1902, such as Figures 15 to 17 Those shown. Similar to Figure 18 In the configuration described, acoustic energy from the transducer 1808 may initially propagate along the y-axis, may reflect from the bead portion 1902' of the cover glass 1902, and may proceed along the x-axis. Figure 19A and Figure 19B In the example shown, the filler 1902' is drawn as a fully formed 45 degree angle, which can produce a 90 degree change in the orientation of the acoustic energy reflected from the filler. It should be understood that the same principles apply to Figure 18The curved cover glass 1802 can be used, and acceptable performance can be achieved with a non-flat bead 1902' (such as the curved edge 1802' described above). The flat bead 1902' shown can be used to provide the desired reflection, but can result in sharp edges that may be uncomfortable for the user to touch. In some examples, a portion of the bead 1902' can be flat, and the sharp edges of the bead can be avoided by rounding the edges. In some examples, the length of the transducer 1908 (e.g., the x-axis dimension) can be equal to or approximately equal to the thickness of the cover glass 1902 (e.g., the y-axis dimension) so that a uniform sound wave 1920 can be transmitted across the entire thickness of the cover glass material. Using the above Figure 2 5, transducer 1908 can be used to detect the touch location of object 1922 on the cover glass. It should be understood that Figure 19A and Figure 19B Shows how to Figure 3B The configuration of the embodiment of the present invention can be integrated into the cover glass of the electronic device to perform touch sensing. In addition, by placing the deformable material 1910 behind the transducer (for example, as a backing material), the same transducer 1908 can be used to perform the above Figures 3 to 4 at the same time. Figure 7 For example, with the force sensing Figure 6A In contrast, cover glass 1902, transducer 1908, deformable material 1910, and housing 1904 may correspond to cover glass 601, transducer 602, deformable material 604, and rigid material 606, respectively. Additionally, although not shown, a second transducer may be included between deformable material 1910 and housing 1904 to match the housing 1904. Figure 6B The configuration shown in .

[0114] Therefore, in accordance with the foregoing, some examples of the present disclosure relate to an electronic device comprising: a cover surface; a deformable material disposed between the cover surface and a housing of the electronic device; and an acoustic transducer coupled to the cover surface and the deformable material and configured to generate a first acoustic wave in the cover surface and a second acoustic wave in the deformable material. Additionally or alternatively, in some examples, the deformable material and the cover surface are further configured to enable the first acoustic wave to propagate in a first direction and the second acoustic wave to propagate in a second direction different from the first direction. Additionally or alternatively, in some examples, the first acoustic wave is incident on a bezel portion of the cover glass along a third direction and is reflected by the bezel portion of the cover glass along a first direction different from the third direction. Additionally or alternatively, in some examples, the first and third directions are opposite to each other. Additionally or alternatively, in some examples, the first and third directions are orthogonal. Additionally or alternatively, in some examples, the deformable material is included in a gasket positioned between the housing and a first side of the cover surface.

[0115] Some examples disclosed herein relate to touch- and force-sensitive devices. The device may include: a surface; a deformable material disposed between the surface and a rigid material such that a force on the surface causes the deformable material to deform; a plurality of transducers coupled to the surface and the deformable material; and a processor circuit coupled to the plurality of transducers. The processing circuit is capable of stimulating the plurality of transducers to transmit ultrasonic waves to the surface and the deformable material; receiving reflected ultrasonic waves from the surface and the deformable material from the plurality of transducers; determining a contact location of an object on the surface based on the reflected ultrasonic waves propagating through the surface and received at the plurality of transducers; and determining a force exerted by the contact on the surface based on one or more reflected ultrasonic waves propagating through the deformable material and received from one or more of the plurality of transducers. Additionally or alternatively, in some examples, the surface may include an exterior surface of the device. Additionally or alternatively, in some examples, the rigid material may include a portion of a housing of the device. Additionally or alternatively, in some examples, the deformable material may form a gasket between a portion of the housing and the exterior surface of the device. In addition to or alternatively to one or more of the examples disclosed above, in some examples, the plurality of transducers may include at least four transducers bonded to the surface. Each of the four transducers may be positioned adjacent to a different one of four corresponding edges of the surface and may be positioned above a portion of a gasket adjacent to a corresponding edge of the device housing. In addition to or alternatively to one or more of the examples disclosed above, in some examples, the processing circuitry may include one or more acoustic touch and force sensing circuits. The acoustic touch and force sensing circuitry may be coupled to the plurality of transducers via direct bonding between the plurality of transducers and the one or more acoustic touch and force sensing circuits, via bonding between the plurality of transducers and a flexible circuit board coupled to the one or more acoustic touch and force sensing circuits, or via bonding between the plurality of transducers and a rigid circuit board coupled to the one or more acoustic touch and force sensing circuits. In addition to or alternatively to one or more of the examples disclosed above, in some examples, the device may further include wiring deposited on the surface adjacent to the plurality of transducers. The processing circuitry may include one or more acoustic touch and force sensing circuits. The one or more acoustic touch and force sensing circuits may be coupled to the plurality of transducers via wiring that couples the one or more acoustic touch and force sensing circuits to deposited on a surface.In addition to or alternatively to one or more of the examples disclosed above, in some examples, stimulating the multiple transducers to transmit ultrasonic waves to the surface and the deformable material and receiving reflected ultrasonic waves from the surface and the deformable material from the multiple transducers may include: stimulating a first transducer of the multiple transducers to transmit a first ultrasonic wave to the surface and receiving a first reflected ultrasonic wave from the first transducer from the surface in response to the transmitted first ultrasonic wave; stimulating a second transducer of the multiple transducers to transmit a second ultrasonic wave to the surface and receiving a second reflected ultrasonic wave from the second transducer from the surface in response to the transmitted second ultrasonic wave; stimulating a third transducer of the multiple transducers to transmit a third ultrasonic wave to the surface and receiving a third reflected ultrasonic wave from the third transducer from the surface in response to the transmitted third ultrasonic wave; and stimulating a fourth transducer of the multiple transducers to transmit a fourth ultrasonic wave to the surface and receiving a fourth reflected ultrasonic wave from the fourth transducer from the surface in response to the transmitted fourth ultrasonic wave. In addition to or alternatively in the examples disclosed above, in some examples, the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave may be transmitted in series to reduce interference between the plurality of transducers. In addition to or alternatively in the examples disclosed above, in some examples, determining the location of the contact of the object on the surface may be based on the first reflected ultrasonic wave, the second reflected ultrasonic wave, the third reflected ultrasonic wave, and the fourth reflected ultrasonic wave. In addition to or alternatively to one or more of the examples disclosed above, in some examples, stimulating the multiple transducers to transmit ultrasonic waves to the surface and the deformable material and receiving reflected ultrasonic waves from the surface and the deformable material from the multiple transducers may also include: stimulating a first transducer of the multiple transducers to transmit a fifth ultrasonic wave to the deformable material and receiving a fifth reflected ultrasonic wave from the first transducer from the deformable material in response to the transmitted fifth ultrasonic wave; stimulating a second transducer of the multiple transducers to transmit a sixth ultrasonic wave to the deformable material and receiving a sixth reflected ultrasonic wave from the second transducer from the deformable material in response to the transmitted sixth ultrasonic wave; stimulating a third transducer of the multiple transducers to transmit a seventh ultrasonic wave to the deformable material and receiving a seventh reflected ultrasonic wave from the third transducer from the deformable material in response to the transmitted seventh ultrasonic wave; and stimulating a fourth transducer of the multiple transducers to transmit an eighth ultrasonic wave to the deformable material and receiving an eighth reflected ultrasonic wave from the fourth transducer from the deformable material in response to the transmitted eighth ultrasonic wave. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the fifth ultrasonic wave, the sixth ultrasonic wave, the seventh ultrasonic wave, and the eighth ultrasonic wave may be transmitted in series to reduce interference among the plurality of transducers.In addition to or alternatively to one or more of the examples disclosed above, in some examples, determining the force exerted by the contact on the surface may be based on the fifth reflected ultrasonic wave, the sixth reflected ultrasonic wave, the seventh reflected ultrasonic wave, and the eighth reflected ultrasonic wave. In addition to or alternatively to one or more of the examples disclosed above, in some examples, determining the force exerted by the contact on the surface may include average time-of-flight measurements corresponding to the fifth reflected ultrasonic wave, the sixth reflected ultrasonic wave, the seventh reflected ultrasonic wave, and the eighth reflected ultrasonic wave. In addition to or alternatively to one or more of the examples disclosed above, in some examples, stimulating the plurality of transducers to transmit ultrasonic waves to a surface and a deformable material and receiving reflected ultrasonic waves from the surface and the deformable material from the plurality of transducers may include: stimulating a first transducer of the plurality of transducers to simultaneously transmit a first ultrasonic wave to the surface and the deformable material; receiving a first reflected ultrasonic wave from the surface from the first transducer in response to the first ultrasonic wave transmitted to the surface, and receiving a first reflected ultrasonic wave from the deformable material from the first transducer in response to the first ultrasonic wave transmitted to the deformable material; stimulating a second transducer of the plurality of transducers to simultaneously transmit a second ultrasonic wave to the surface and the deformable material; receiving a second reflected ultrasonic wave from the surface from the second transducer in response to the second ultrasonic wave transmitted to the surface and receiving a second reflected ultrasonic wave from the second transducer from the deformable material in response to the second ultrasonic wave transmitted to the deformable material; stimulating a third transducer of the plurality of transducers to simultaneously transmit a third ultrasonic wave to the surface and the deformable material; receiving a third reflected ultrasonic wave from the third transducer from the surface in response to the third ultrasonic wave transmitted to the surface, and receiving a third reflected ultrasonic wave from the third transducer from the deformable material in response to the third ultrasonic wave transmitted to the deformable material; and stimulating a fourth transducer of the plurality of transducers to simultaneously transmit a fourth ultrasonic wave to the surface and the deformable material; receiving a fourth reflected ultrasonic wave from the fourth transducer from the surface in response to the fourth ultrasonic wave transmitted to the surface, and receiving a fourth reflected ultrasonic wave from the fourth transducer from the deformable material in response to the fourth ultrasonic wave transmitted to the deformable material. In addition to or alternatively to one or more of the examples disclosed above, in some examples, the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave may be transmitted in series to reduce interference between the plurality of transducers. In addition to or alternatively to one or more of the examples disclosed above, in some examples, determining the location of the object's contact on the surface may be based on a first reflected ultrasonic wave from the surface, a second reflected ultrasonic wave from the surface, a third reflected ultrasonic wave from the surface, and a fourth reflected ultrasonic wave from the surface.Additionally or alternatively to one or more of the examples disclosed above, in some examples, determining the force exerted by a contact on a surface can be based on a first reflected ultrasonic wave from the deformable material, a second reflected ultrasonic wave from the deformable material, a third reflected ultrasonic wave from the deformable material, and a fourth reflected ultrasonic wave from the deformable material. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the processing circuitry can include a force detection circuit. The force detection circuitry can be configured to use time gating to detect one or more transitions in the reflected ultrasonic waves to determine the arrival time of the reflected ultrasonic waves. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the processing circuitry can include one or more acoustic touch and force sensing circuits. Each of the one or more acoustic touch and force sensing circuits can include an acoustic touch sensing circuit implemented on a first integrated circuit and an acoustic force sensing circuit implemented on a second integrated circuit separate from the first integrated circuit. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the processing circuitry can include one or more acoustic touch and force sensing circuits. Each of the one or more acoustic touch and force sensing circuits can include an acoustic transmit circuit and an acoustic receive circuit. The acoustic transmit circuitry may be implemented on a first integrated circuit, and the acoustic receive circuitry may be implemented on a second integrated circuit separate from the first integrated circuit.

[0116] Some examples of the present disclosure relate to a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium may store instructions that, when executed by a device comprising a surface, a deformable material, a plurality of acoustic transducers coupled to the surface and the deformable material, and a processing circuit, cause the processing circuit to: for each of the plurality of acoustic transducers: simultaneously transmit an ultrasonic wave in the surface toward opposite edges of the surface and transmit the ultrasonic wave through the deformable material; receive an ultrasonic reflection from the deformable material in response to the ultrasonic wave transmitting through the deformable material and traversing the thickness of the deformable material; receive the ultrasonic reflection from the surface; determine a first time-of-flight between the ultrasonic wave transmitted through the deformable material and the ultrasonic reflection from the deformable material; and determine a second time-of-flight between the ultrasonic wave transmitted in the surface and the ultrasonic reflection from the surface; the instructions may further cause the processing circuit to determine a position of an object on the surface based on corresponding second time-of-flight measurements corresponding to the plurality of transducers; and determine an amount of force exerted by the object on the surface based on corresponding first time-of-flight measurements corresponding to the plurality of transducers.

[0117] Some examples of the present disclosure relate to a method for determining the position of an object on a surface and the amount of force exerted by the object on the surface. The method may include: for each of a plurality of acoustic transducers: transmitting a first ultrasonic wave in the surface toward an opposite edge of the surface; receiving a first ultrasonic reflection from the surface; and determining a first time of flight between the first ultrasonic wave transmitted in the surface and the first ultrasonic reflection from the surface; and determining the position of the object on the surface based on the corresponding first time of flight measurements corresponding to the plurality of transducers. The method may also include: for each of the plurality of acoustic transducers: transmitting a second ultrasonic wave through a deformable material; receiving a second ultrasonic reflection from the deformable material in response to the second ultrasonic wave being transmitted through the deformable material and passing through the thickness of the deformable material; and determining a second time of flight between the second ultrasonic wave transmitted through the deformable material and the second ultrasonic reflection from the deformable material. The method may also include determining the amount of force exerted by the object on the surface based on the corresponding second time of flight measurements corresponding to the plurality of transducers.

[0118] Some examples disclosed herein relate to touch- and force-sensitive devices. The device may include: a surface; a deformable material disposed between the surface and a rigid material such that a force on the surface causes the deformable material to deform; one or more transducers coupled to the surface and the deformable material and configured to transmit and receive ultrasonic waves to and from the surface and the deformable material; and a processor. The processor may determine a contact location of an object on the surface based on the ultrasonic waves propagating through the surface, and may determine a force exerted by the contact on the surface based on the ultrasonic waves propagating through the deformable material. In addition to or alternatively to one or more of the examples disclosed above, in some examples, the surface may include a glass or sapphire outer surface of the device, the rigid material may include a portion of a metal housing of the device, and the deformable material may form a gasket between the metal housing and the surface. In addition to or alternatively to one or more of the examples disclosed above, in some examples, the one or more transducers may include at least a first transducer coupled to the deformable material. The first transducer may be configured to transmit the ultrasonic waves through the thickness of the deformable material. Additionally or alternatively, in some examples, the first transducer may be configured to receive one or more ultrasonic reflections from a boundary between the deformable material and the rigid material. Additionally or alternatively, in some examples, the one or more transducers may include at least a second transducer coupled between the deformable material and the rigid material. The second transducer may be configured to receive ultrasonic waves transmitted through the thickness of the deformable material. Additionally or alternatively, in some examples, the one or more transducers may include at least one transducer configured to simultaneously transmit ultrasonic waves in the surface and through the deformable material. Additionally or alternatively, in some examples, the one or more transducers may include four transducers. Each of the four transducers may be positioned adjacent to a respective edge of the surface. Additionally or alternatively, in some examples, the device may further include an ultrasonically absorbing material coupled to the deformable material. The ultrasonically absorbing material may be configured to dampen ultrasonic oscillations in the deformable material.In addition to or alternatively to one or more of the examples disclosed above, in some examples, determining the contact location of the object on the surface may include: determining a first time of flight of an ultrasonic wave propagating between a first edge of the surface and a first leading edge of the object adjacent to the first edge, determining a second time of flight of an ultrasonic wave propagating between a second edge of the surface and a second leading edge of the object adjacent to the second edge, determining a third time of flight of an ultrasonic wave propagating between a third edge of the surface and a third leading edge of the object adjacent to the third edge, and determining a fourth time of flight of an ultrasonic wave propagating between a fourth edge of the surface and a fourth leading edge of the object adjacent to the fourth edge. In addition to or alternatively to one or more of the examples disclosed above, in some examples, determining the force exerted by the contact on the surface may include determining a time of flight of an ultrasonic wave propagating from a first side of the deformable material and reflected from a second side of the deformable material opposite the first side.

[0119] Some examples disclosed herein relate to a method. The method may include transmitting an ultrasonic wave through a surface, receiving an ultrasonic reflection from the surface, transmitting the ultrasonic wave through a deformable material, receiving an ultrasonic reflection from the deformable material, determining a location of an object in contact with the surface based on the ultrasonic reflection received from the surface, and determining a force exerted by the object in contact with the surface based on the ultrasonic reflection received from the deformable material. Additionally or alternatively, in some examples, at least one of the ultrasonic waves transmitted through the surface and at least one of the ultrasonic waves transmitted through the deformable material are transmitted simultaneously. Additionally or alternatively, in some examples, at least one of the ultrasonic waves transmitted through the surface and at least one of the ultrasonic waves transmitted through the deformable material are transmitted by a common transducer. Additionally or alternatively, in some examples, the method may further include determining a time of flight through the deformable material based on a time difference between transmitting the ultrasonic wave through the deformable material and receiving an ultrasonic reflection from the deformable material. The force exerted by the object may be determined based on the time of flight through the deformable material. In addition to or alternatively to one or more of the examples disclosed above, in some examples, the ultrasonic reflection from the deformable material may originate from an ultrasonic wave that propagates through the deformable material and reaches a boundary between the deformable material and the rigid material. In addition to or alternatively to one or more of the examples disclosed above, in some examples, the ultrasonic reflection from the deformable material may be received before the ultrasonic reflection from the surface. In addition to or alternatively to one or more of the examples disclosed above, in some examples, the method may further include determining a time of flight in the surface based on a time difference between transmitting the ultrasonic wave in the surface and receiving the ultrasonic reflection from the surface corresponding to the object in contact with the surface. Determining the position of the object may include determining a distance from an edge of the surface to a leading edge of the object adjacent to the edge of the surface based on the time of flight in the surface.

[0120] Some examples of the present disclosure relate to a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium may store instructions that, when executed by a device comprising a surface, a plurality of acoustic transducers coupled to an edge of the surface, acoustic touch and force sensing circuitry, and one or more processors, cause the acoustic touch and force sensing circuitry and the one or more processors to: for each of the plurality of acoustic transducers: simultaneously transmit an ultrasonic wave in the surface toward opposite edges of the surface and transmit the ultrasonic wave through a deformable material; receive an ultrasonic reflection from the deformable material in response to the ultrasonic wave transmitting through the deformable material and traversing a thickness of the deformable material; receive the ultrasonic reflection from the surface; determine a first time-of-flight between the ultrasonic wave transmitted through the deformable material and the ultrasonic reflection from the deformable material; and determine a second time-of-flight between the ultrasonic wave transmitted in the surface and the ultrasonic reflection from the surface; the instructions may further cause the acoustic touch and force sensing circuitry and the one or more processors to determine a position of an object on the surface based on corresponding second time-of-flight measurements corresponding to the plurality of transducers, and determine an amount of force exerted by the object on the surface based on corresponding first time-of-flight measurements corresponding to the plurality of transducers. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the ultrasonic waves transmitted in the surface and transmitted through the deformable material may include shear waves. Additionally or alternatively to one or more of the examples disclosed above, in some examples, ultrasonic reflections may be received from the deformable material before ultrasonic reflections from the surface.

[0121] Although the examples of the present disclosure have been fully described with reference to the accompanying drawings, it should be noted that various changes and modifications will become apparent to those skilled in the art. It should be understood that such changes and modifications are considered to be included within the scope of the examples of the present disclosure as defined by the appended claims.

Claims

1. A touch and force sensitive device comprising: surface; a deformable material disposed between the surface and the rigid material such that a force applied by contact of an object on the surface causes deformation of the deformable material; a plurality of transducers coupled to the surface and the deformable material and configured to transmit ultrasonic waves to the surface and the deformable material and to receive reflected ultrasonic waves from the surface and the deformable material, wherein the plurality of transducers comprises a first transducer coupled to the surface and the deformable material and configured to transmit a subset of the ultrasonic waves to the surface and the deformable material and to receive a subset of the reflected ultrasonic waves from the surface and the deformable material; as well as a processing circuit coupled to the plurality of transducers and configured to: energizing the plurality of transducers to transmit the ultrasonic waves; receiving the reflected ultrasonic wave; determining a location of the contact on the surface based on one or more of the reflected ultrasonic waves propagating in the surface and received at one or more of the plurality of transducers; as well as A force exerted by the contact on the surface is determined based on one or more reflected ultrasonic waves propagating in the deformable material and received at one or more transducers of the plurality of transducers.

2. The apparatus according to claim 1, wherein: said surface comprising an outer surface of said device, The rigid material comprises a portion of the housing of the device, and The deformable material forms a gasket between the portion of the housing and an exterior surface of the device.

3. The device of claim 2, wherein the plurality of transducers comprises at least four transducers bonded to the surface, wherein each of the four transducers is disposed adjacent to a different one of four corresponding edges of the surface and adjacent to a corresponding edge of the housing of the device on a portion of the gasket.

4. The device of claim 3, wherein the processing circuit comprises one or more acoustic touch and force sensing circuits coupled to the plurality of transducers via direct bonding between the plurality of transducers and the one or more acoustic touch and force sensing circuits, via bonding between the plurality of transducers and a flexible circuit board coupled to the one or more acoustic touch and force sensing circuits, or via bonding between the plurality of transducers and a rigid circuit board coupled to the one or more acoustic touch and force sensing circuits.

5. The device according to claim 3, further comprising: wiring deposited on the surface adjacent the plurality of transducers; wherein the processing circuitry includes one or more acoustic touch and force sensing circuits; as well as Wherein the one or more acoustic touch and force sensing circuits are coupled to the plurality of transducers via coupling of the one or more acoustic touch and force sensing circuits to the wiring deposited on the surface.

6. The device according to claim 1, wherein: Exciting the plurality of transducers and receiving the reflected ultrasonic waves comprises: exciting the first transducer of the plurality of transducers to transmit a first ultrasonic wave toward the surface, and receiving a first reflected ultrasonic wave from the surface at the first transducer in response to the transmitted first ultrasonic wave; exciting a second transducer of the plurality of transducers to transmit a second ultrasonic wave toward the surface, and receiving a second reflected ultrasonic wave from the surface at the second transducer in response to the transmitted second ultrasonic wave; exciting a third transducer of the plurality of transducers to transmit a third ultrasonic wave toward the surface, and receiving a third reflected ultrasonic wave from the surface at the third transducer in response to the transmitted third ultrasonic wave; and A fourth transducer of the plurality of transducers is excited to transmit a fourth ultrasonic wave toward the surface, and a fourth reflected ultrasonic wave from the surface is received at the fourth transducer in response to the transmitted fourth ultrasonic wave. 7 . The apparatus according to claim 6 , wherein the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave are transmitted in series to reduce interference between the plurality of transducers. 8 . The apparatus of claim 6 , wherein determining the location of the contact on the surface is based on the first reflected ultrasonic wave, the second reflected ultrasonic wave, the third reflected ultrasonic wave, and the fourth reflected ultrasonic wave.

9. The device according to claim 6, wherein: Exciting the plurality of transducers and receiving the reflected ultrasonic waves further comprises: energizing the first transducer of the plurality of transducers to transmit a fifth ultrasonic wave to the deformable material, and receiving a fifth reflected ultrasonic wave from the deformable material at the first transducer in response to the transmitted fifth ultrasonic wave; exciting the second transducer of the plurality of transducers to transmit a sixth ultrasonic wave to the deformable material, and receiving a sixth reflected ultrasonic wave from the deformable material at the second transducer in response to the transmitted sixth ultrasonic wave; exciting the third transducer of the plurality of transducers to transmit a seventh ultrasonic wave to the deformable material, and receiving a seventh reflected ultrasonic wave from the deformable material at the third transducer in response to the transmitted seventh ultrasonic wave; and The fourth transducer of the plurality of transducers is excited to transmit an eighth ultrasonic wave to the deformable material, and an eighth reflected ultrasonic wave is received at the fourth transducer from the deformable material in response to the transmitted eighth ultrasonic wave.

10. The device according to claim 9, wherein: The fifth ultrasonic wave, the sixth ultrasonic wave, the seventh ultrasonic wave, and the eighth ultrasonic wave are transmitted in series to reduce interference among the plurality of transducers.

11. The device according to claim 9, wherein: Determining the force exerted by the contact on the surface is based on the fifth reflected ultrasonic wave, the sixth reflected ultrasonic wave, the seventh reflected ultrasonic wave, and the eighth reflected ultrasonic wave.

12. The device according to claim 11, wherein Determining a force exerted by the contact on the surface includes averaging time-of-flight measurements corresponding to the fifth, sixth, seventh, and eighth reflected ultrasonic waves.

13. The apparatus according to claim 1, wherein: Exciting the plurality of transducers and receiving the reflected ultrasonic waves comprises: energizing the first transducer of the plurality of transducers to simultaneously transmit a first ultrasonic wave toward the surface and the deformable material; receiving, at the first transducer, a first reflected ultrasonic wave from the surface in response to the first ultrasonic wave being transmitted to the surface, and receiving, at the first transducer, a first reflected ultrasonic wave from the deformable material in response to the first ultrasonic wave being transmitted to the deformable material; energizing a second transducer of the plurality of transducers to simultaneously transmit a second ultrasonic wave toward the surface and the deformable material; receiving, at the second transducer, a second reflected ultrasonic wave from the surface in response to the second ultrasonic wave being transmitted to the surface, and receiving, at the second transducer, a second reflected ultrasonic wave from the deformable material in response to the second ultrasonic wave being transmitted to the deformable material; energizing a third transducer of the plurality of transducers to simultaneously transmit a third ultrasonic wave toward the surface and the deformable material; receiving, at the third transducer, a third reflected ultrasonic wave from the surface in response to the third ultrasonic wave being transmitted to the surface, and receiving, at the third transducer, a third reflected ultrasonic wave from the deformable material in response to the third ultrasonic wave being transmitted to the deformable material; and energizing a fourth transducer of the plurality of transducers to simultaneously transmit a fourth ultrasonic wave toward the surface and the deformable material; In response to the fourth ultrasonic wave being transmitted to the surface, a fourth reflected ultrasonic wave from the surface is received at the fourth transducer, and in response to the fourth ultrasonic wave being transmitted to the deformable material, a fourth reflected ultrasonic wave from the deformable material is received at the fourth transducer. 14 . The apparatus according to claim 13 , wherein the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave are transmitted in series to reduce interference between the plurality of transducers.

15. The device according to claim 13, wherein the position of the contact on the surface is determined based on the one or more reflected ultrasonic waves among the reflected ultrasonic waves propagating in the surface based on the first reflected ultrasonic wave from the surface, the second reflected ultrasonic wave from the surface, the third reflected ultrasonic wave from the surface and the fourth reflected ultrasonic wave from the surface; and wherein the force exerted by the contact on the surface is determined based on the one or more reflected ultrasonic waves propagating in the deformable material based on the first reflected ultrasonic wave from the deformable material, the second reflected ultrasonic wave from the deformable material, the third reflected ultrasonic wave from the deformable material and the fourth reflected ultrasonic wave from the deformable material.

16. The device of claim 1, wherein the processing circuit comprises a force detection circuit configured to detect one or more transitions in the reflected ultrasonic waves of the one or more reflected ultrasonic waves using time gating to determine a time of arrival of the reflected ultrasonic waves.

17. The device of claim 1 , wherein the processing circuit comprises one or more acoustic touch and force sensing circuits, each of the one or more acoustic touch and force sensing circuits comprising an acoustic touch sensing circuit implemented on a first integrated circuit and an acoustic force sensing circuit implemented on a second integrated circuit separate from the first integrated circuit.

18. The device of claim 1 , wherein the processing circuit comprises one or more acoustic touch and force sensing circuits, each of the one or more acoustic touch and force sensing circuits comprising an acoustic transmitting circuit and an acoustic receiving circuit, wherein the acoustic transmitting circuit is implemented on a first integrated circuit and the acoustic receiving circuit is implemented on a second integrated circuit separate from the first integrated circuit.

19. A non-transitory computer-readable storage medium storing instructions that, when executed by a device comprising a surface, a deformable material, a plurality of acoustic transducers coupled to the surface and the deformable material, and a processing circuit, cause the processing circuit to: For each acoustic transducer of the plurality of acoustic transducers: transmitting ultrasonic waves in the surface simultaneously toward opposite edges of the surface and through the deformable material; receiving ultrasonic reflections from the deformable material in response to the ultrasonic wave transmitted through the deformable material passing through a thickness of the deformable material; receiving ultrasonic reflections from the surface in response to the ultrasonic wave being transmitted in the surface toward the opposite edge of the surface; determining a first time of flight between the ultrasonic wave transmitted through the deformable material and a reflection of the ultrasonic wave from the deformable material; as well as determining a second time of flight between the ultrasonic wave transmitted in the surface and the ultrasonic wave reflected from the surface; determining a position of an object contacting the surface based on one or more respective second time-of-flight measurements corresponding to one or more acoustic transducers of the plurality of acoustic transducers; as well as An amount of force exerted by the object on the surface is determined based on one or more respective first time-of-flight measurements corresponding to one or more acoustic transducers of the plurality of acoustic transducers.

20. A method for determining a position of an object contacting a surface and an amount of force exerted by the object contacting the surface, the method comprising: For each acoustic transducer of the plurality of acoustic transducers: transmitting a first ultrasonic wave in the surface toward opposite edges of the surface; receiving a first ultrasonic reflection from the surface; as well as determining a first time of flight between the first ultrasonic wave transmitted in the surface and the first ultrasonic wave reflection from the surface; determining a position of the object contacting the surface based on one or more respective first time-of-flight measurements corresponding to one or more acoustic transducers of the plurality of acoustic transducers; For each acoustic transducer of the plurality of acoustic transducers: transmitting a second ultrasonic wave through a deformable material disposed between the surface and the rigid material; receiving a second ultrasonic reflection from the deformable material in response to the second ultrasonic wave transmitted through the deformable material passing through the thickness of the deformable material; as well as determining a second time of flight between the second ultrasonic wave transmitted through the deformable material and the second ultrasonic wave reflected from the deformable material; as well as An amount of force exerted by the object contacting the surface is determined based on one or more respective second time-of-flight measurements corresponding to one or more acoustic transducers of the plurality of acoustic transducers.

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