BR112016013140B1 - MICROMECHANICAL ULTRASONIC TRANSDUCERS AND SCREEN - Google Patents

Abstract

MICROMECHANICAL AND SCREEN ULTRASONIC TRANSDUCERS. A device may include a one- or two-dimensional array of ultrasonic transducer elements (PMUT) positioned below, beside, with, on, or above a backplate of a visual screen. The backplate may be a thin-film transistor (TFT) backplate. The PMUT element array can be either a piezoelectric micromechanical ultrasonic transducer (PMUT) array or a capacitive micromechanical ultrasonic transducer (CMUT) array. The PMUT matrix can be configured to work in modes corresponding to various frequency bands. When operating in low frequency mode, the equipment may be capable of gesture detection. A high frequency mode may include a fingerprint detection mode or a stylus detection mode.

Description

PRIORITY CLAIMS

[0001] This application claims priority over US Provisional Patent Application No. 61/915,361, filed on December 12, 2013 and entitled “MICROMECHANICAL ULTRASONIC TRANSDUCERS AND DISPLAY,” and US Provisional Patent Application No. 62/022,140 , filed July 8, 2014 and entitled “PIEZOELECTRIC ULTRASONIC TRANSDUCER AND PROCESS,” which are incorporated herein by reference.

TECHNICAL FIELD

[0002] This disclosure relates to screens that include sensor elements, and more particularly to a piezoelectric ultrasonic transducer suitable for use in an electronic sensor array or interactive screen for biometric detection, imaging, and touch or gesture recognition.

RELATED TECHNOLOGY DESCRIPTION

[0003] Current touch-sensitive display screens, such as liquid crystal display (LCD) and organic light-emitting diode (OLED) touch-sensitive screens, generally include pixels of at least three (e.g. RGB) sub-pixel elements and have overlay capacitive touch screens to detect a finger touch. The resolution of capacitive touch screens is generally insufficient for fingerprint imaging or stylus detection, and the detection range is generally insufficient for gesture detection, because capacitive touch detection is usually limited to a few millimeters from the surface of the screen. touch screen.

SUMMARY

[0004] The systems, methods, and devices of disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes described herein. An innovative aspect of the subject matter described in the present disclosure can be implemented in equipment that includes an array of piezoelectric micromechanical ultrasonic transducer elements (PMUT) positioned in close proximity (e.g., below, to the side, on or above) a screen. The apparatus may include a control system.

[0005] In some implementations, the control system may be able to make a determination of when to operate at least a portion of the PMUT matrix in a low-frequency mode and/or in a high-frequency mode. The control system may be capable of controlling at least a portion of the PMUT matrix to operate in the low frequency mode and/or the high frequency mode, as determined. The display device may include an interface system. In some examples, the determination may be made, at least in part, according to input received from the interface system.

[0006] According to some implementations, the low frequency mode can correspond to a frequency range from approximately 50 kHz to 200 kHz. In some examples, the low frequency mode may correspond to a gesture detection mode, whereby gestures in the free space close to the screen can be detected. According to some implementations, the high frequency mode may correspond to a frequency range from approximately 1 MHz to 25 MHz. In some examples, the high frequency mode may correspond to a fingerprint sensor mode or a fingerprint detection mode. graphic pen.

[0007] In some implementations, the control system may be able to perform an authentication process based, at least in part, on the acquired fingerprint data while the PMUT matrix operates in fingerprint sensor mode. In some examples, the equipment may include a memory system. In some of these examples, the authentication process might involve the following: providing an instruction, via the screen, to place at least one finger on a surface of the display device; receiving, via at least a portion of the PMUT matrix, at least one fingerprint image; determining received fingerprint data corresponding to the at least one fingerprint image; and comparing the received fingerprint data with the fingerprint data stored in the memory system.

[0008] According to some implementations, the control system may be able to make a determination of when to operate at least a portion of the PMUT matrix in a high frequency mode, and/or a medium frequency mode. The control system may be capable of controlling at least a portion of the PMUT matrix to operate in high frequency mode, low frequency mode and/or medium frequency mode, as determined. In some examples, the mid-frequency mode may correspond to a frequency range of approximately 200 kHz to 1 MHz. In accordance with some implementations, the display device may be capable of providing touch sensor functionality when the control system is controlling at least a portion of the PMUT matrix to operate in medium frequency mode.

[0009] In some implementations, the control system may be able to control some PMUT elements of the PMUT matrix to operate in low frequency mode and the other PMUT elements of the PMUT matrix to operate in high frequency mode. Alternatively or additionally, the control system may be able to control the same PMUT element of the PMUT matrix to operate in low frequency mode and to operate in high frequency mode. In some examples, the PMUT array may be a piezoelectric micromechanical ultrasonic transducer array (pMUT) or a capacitive micromechanical ultrasonic transducer array (cMUT).

[0010] According to some implementations, the control system may be able to address at least a portion of the PMUT matrix to at least one of wavefront beamforming, beam steering, receive-side beamforming, or selective reading of returned signals. For example, in some implementations, the control system may be able to address at least a portion of the PMUT matrix to produce wavefronts of a substantially flat, spherical or cylindrical shape. In some implementations, the control system may be able to address at least a portion of the PMUT matrix to produce constructive or destructive interference at at least one location.

[0011] In some examples, the control system may be able to excite the PMUT elements of the PMUT matrix and detect responses through the same PMUT elements. Alternatively or additionally, the control system may be capable of controlling a first PMUT element of the PMUT matrix as an acoustic transmitter and a second PMUT element of the PMUT matrix as an acoustic receiver.

[0012] According to some implementations, at least a portion of the PMUT matrix may be an active matrix PMUT matrix. In some examples, the active matrix PMUT matrix may include trigger circuit and detection circuit. In some implementations, the PMUT matrix of the active matrix may include at least one of a row and column addressing circuit, multiplexer circuit, demultiplexer circuit, local amplification circuit, and/or analog-to-digital converter circuit.

[0013] In some implementations, at least a portion of the PMUT matrix is arranged substantially behind the entire screen. In some of these implementations, a single PMUT element of the PMUT array may correspond to a second screen pixel. However, in some examples, at least a portion of the PMUT matrix is disposed of substantially only a portion of the screen.

[0014] Alternatively or additionally, at least a portion of the PMUT matrix is disposed in a peripheral area of the screen. According to some implementations, the control system may be capable of controlling a portion of the PMUT matrix that is disposed in the peripheral area of the screen for fingerprint sensor functionality, signature pad functionality, stylus detection functionality, gesture detection functionality and/or button functionality.

[0015] In some examples, at least a portion of the PMUT array is disposed on a substrate. According to some implementations, the substrate may be a glass substrate. However, in alternative implementations the substrate may be formed of another suitable material, which may or may not be transparent depending on the specific implementation.

[0016] According to some implementations, at least one array of thin-film transistors (TFTs) may also be disposed on the substrate. In some of these implementations, at least one array of TFTs may include circuitry to control the display. In some examples, at least one array of TFTs may include circuitry for controlling at least a portion of the PMUT array. In some of these implementations, the circuit to control at least a portion of the PMUT matrix and the circuit to control the screen may be able to share a flexible cable. According to some implementations, at least one array of TFTs including circuitry for controlling the display can be disposed on a second substrate.

[0017] In some implementations, the equipment may include a glass cover and electrodes arranged in the glass cover. The electrodes may be configured for electrical connections on the top side of the circuit to control at least a portion of the PMUT matrix. In some of these implementations, the electrodes may be configured for connections to the circuit for at least one PMUT element which may be disposed about a periphery of the screen.

[0018] Other features, aspects and advantages will be evident from an analysis of the disclosure. Note that the relative dimensions of the drawings and other diagrams of the present disclosure may not be drawn to scale. The sizes, thicknesses, arrangements, materials, etc. shown and described in the present disclosure are by way of example only and should not be construed as limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1A is a block diagram showing examples of elements of a display device.

[0020] Figure 1B shows an example of a PMUT element.

[0021] Figure 1C shows an example of a CMUT element.

[0022] Figure 2 is a graph showing examples of frequency ranges for PMUT excitation.

[0023] Figure 3A shows an example of a PMUT matrix.

[0024] Figures 3B-3F show several examples of circuit elements and PMUT elements.

[0025] Figure 4 shows another example of active components and a PMUT matrix on the same substrate.

[0026] Figure 5A shows an example of a display device that includes a PMUT matrix.

[0027] Figure 5B shows an example of a display device that has a PMUT matrix that is coextensive with a screen pixel matrix.

[0028] Figure 5C shows an exemplary stack for a display device that includes an LCD screen and a PMUT matrix.

[0029] Figure 5D shows an exemplary stack for a display device that includes an OLED screen and a PMUT matrix.

[0030] Figure 6A shows an example of a display device that includes a PMUT matrix behind only a portion of a screen.

[0031] Figures 6B-D show an example of a display device that includes a PMUT matrix near a periphery of a screen.

[0032] Figures 7A-7F show examples of PMUT arrays arranged in peripheral areas of a screen.

[0033] Figures 8A and 8B show sample system block diagrams illustrating a display device that includes at least one PMUT matrix as described herein.

[0034] Reference numbers and similar designations in the various drawings indicate similar elements.

DETAILED DESCRIPTION

[0035] The following description refers to certain implementations for the purposes of describing the innovative aspects of this disclosure. However, a person skilled in the art will readily recognize that the teachings described herein can be applied in a variety of different ways. The described implementations can be implemented in any device, device or system that can be capable of displaying an image, whether moving (such as video) or stationary (such as still images), and whether textual, graphic or pictorial. More particularly, it is contemplated that the described implementations may be included in, or associated with, a variety of electronic devices, such as, but not limited to: mobile phones, multimedia Internet-enabled cellular phones, mobile television receivers, wireless devices, smartphones , Bluetooth devices, personal data assistants (PDAs), wireless e-mail receivers, handheld or portable computers, netbooks, notebooks, smartbooks, tablets, printers, copiers, scanners, fax devices, positioning system receivers/navigators global (GPS), cameras, digital media players (such as MP3 players), camcorders, game consoles, wristwatches, watches, calculators, television monitors, flat panel monitors, electronic reading devices (e.g. , e-readers), mobile health devices, computer monitors, auto monitors (including odometer and speedometer screens, etc.), cockpit controls and/or displays, camera view screens (such as a rear view on a vehicle), electronic photographs, electronic billboards or signs, projectors, architectural structures, microwaves, refrigerators, stereos, tape recorders or cassette players, DVD players, CD players, VCRs, radios, portable memory chips , washers, dryers, washer/dryers, parking meters, packaging (such as in electromechanical systems (EMS) applications, including microelectromechanical systems (MEMS) applications as well as non-EMS applications), aesthetic structures (such as the display of images in a piece of jewelry or clothing) and a variety of EMS devices. The teachings here can also be used in non-visualization applications such as, but not limited to, electronic switching devices, radio frequency filters, sensors, accelerometers, gyroscopes, motion sensing devices, magnetometers, inertial components for consumer electronics , consumer electronics parts, varactors, liquid crystal devices, electrophoresis devices, drive schemes, manufacturing processes, and electronic test equipment. Thus, the teachings are not intended to be limited to the embodiments represented solely in the Figures, but rather have wide applicability as will be readily apparent to a person skilled in the art.

[0036] It can be challenging to provide a gesture detection system and/or a fingerprint imaging system on a display device, especially on a mobile display device. Capacitive touch systems (eg projected capacitive touch or PCT) are included with a mobile display device. However, the resolution of capacitive touch screens is generally insufficient for fingerprint imaging or stylus detection. Furthermore, the detection range provided by capacitive touch screens is generally insufficient for gesture detection, because capacitive touch detection is typically limited to a few millimeters from the surface of the touchscreen.

[0037] Some implementations disclosed here include equipment that has a mono- or bidirectional array of ultrasonic transducer elements (PMUT) positioned adjacent (eg, below, beside, with, on, or above) a backplate of a screen. The backplane, for example, may be a thin-film transistor (TFT) backplane. The PMUT matrix or sub-matrices thereof can be configurable to work in modes corresponding to various frequency bands. When operating in low frequency mode, the equipment may be capable of gesture detection. A high frequency mode can, for example, be a fingerprint detection mode, a stylus detection mode or a touch detection mode. In some implementations, a portion of the PMUT matrix or PMUT sub-matrix elements may operate in a low-frequency mode, and a second portion of the PMUT matrix or sub-array may operate in a high-frequency mode. In some implementations, the PMUT elements of the PMUT matrix can operate in either a high-frequency mode or a low-frequency mode.

[0038] Particular aspects of the subject described in the present disclosure may be implemented to realize one or more of the following potential advantages. Some implementations may provide a PMUT matrix capable of both gesture detection and fingerprint imaging. In some of these implementations, the PMUT array may be capable of transmitting and receiving ultrasonic signals through at least a portion of an array of display pixels. Such implementations can reduce the peripheral area of a display device that is not occupied by the screen. In some implementations, the PMUT matrix may also provide touch sensor functionality. In some of these implementations, the touchscreen normally provided with a display device may be omitted. However, in other implementations, at least a portion of the PMUT array, which may provide fingerprint sensor, signature pad, stylus detection, gesture detection and/or button functionality, may be located in a peripheral zone.

[0039] Furthermore, PMUT devices have generally been fabricated on a silicon substrate or insulator on silicon (SOI) with connections made to the circuit external to the substrate. Such configurations can limit the number of PMUT devices in an array, can require a large number of interconnects for external circuitry, and can potentially add expense, packaging restrictions, and loss of signal integrity. In some implementations provided here, a PMUT matrix can be co-fabricated with TFT circuits on the same substrate, which can reduce the number of external circuits to interconnect and can potentially reduce costs and improve signal integrity. Co-fabrication of PMUT elements with TFT circuit allows for typical large die sizes and mobile and stationary screens. Co-fabrication of PMUT elements and TFT circuits on the same (eg common) substrate reduces the number of parts to assemble into a display device, and can reduce the overall thickness of the display device. The number of external interconnections can be greatly reduced with large die sizes, as many of the interconnections between PMUT elements and TFT circuitry can be made with metal traces on the TFT substrate.

[0040] A piezoelectric micromechanical ultrasonic transducer (PMUT) array may include one or more microstructures such as diaphragms, plates, membranes, or ribbons that can be piezoelectrically actuated. A piezoelectric layer of deposited thin film and associated electrodes formed on, in, or under the microstructure can serve to drive the microstructure in one or more ways to generate ultrasonic waves. Ultrasonic waves can be used to detect free space gestures in some implementations. In other implementations, ultrasonic waves can be used to detect touches on the surface of a display device. Ultrasonic waves of high frequencies (smaller wavelengths) can be used to detect a stylus or other small or finely-featured object placed on the screen surface. In some implementations, a high density (e.g., about 500 pixels per inch) of PMUT elements in an array of sufficient size can be used to detect a stylus tip and/or image the peaks and valleys of a fingerprint. for verifying or authenticating a user. PMUT elements can be used as ultrasonic receivers, configured to detect ultrasonic waves that can be received after being reflected from an object in the air or on the surface of the screen. Many examples of PMUT matrices are provided in this disclosure and associated applications incorporated by reference in the present application. However, in some implementations a micromechanical ultrasonic transducer (MUT) array may include other types of MUT elements, such as capacitive micromechanical ultrasonic transducer (CMUT) elements. A more detailed description of the PMUT elements and CMUTs is described below with reference to Figures 1B and 1C.

[0041] Figure 1A is a block diagram showing examples of elements of a display device. In this example, the display device 40 includes a screen 30, a PMUT matrix 105 and a control system 110. The PMUT matrix 105 may be adjacent to the screen 30. In some implementations, the PMUT matrix 105 may be co-extensive with the display area active and formed substantially on the same plane as the screen subpixels (eg cell configurations). In some implementations, the PMUT matrix 105 can be substantially the same size as the screen 30 still positioned behind the active area of the screen. In some implementations, at least a portion of the PMUT matrix 105 may be disposed substantially behind the entire screen 30. In some implementations, the PMUT matrix 105 may be disposed substantially behind a portion of the screen 30. Alternatively, or additionally, at least a portion of the PMUT matrix 105 may be disposed in a peripheral area of the screen 30, such as an area outside the active display area of a display module. Numerous examples of these and other configurations are provided here.

[0042] Portions of the PMUT matrix 105 disposed in a peripheral area of the screen 30 can, for example, be controlled by the control system 110 to provide fingerprint sensor functionality, signature pad functionality or touchpad (e.g. stylus graphic) , graphic pen detection functionality, gesture detection functionality, and/or button functionality. Control button functionality may involve some aspect of display device 40, with or without authentication functionality. Therefore, these buttons can be referred to as “authentication” buttons or “de-authentication” buttons.

[0043] The PMUT matrix 105 may, for example, be a PMUT matrix or in some implementations a CMUT matrix. Control system 110 may include one or more processors, such as one or more general purpose single- or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays ( FPGA) or other programmable logic devices, discrete gate or transistor logic such as TFTs, discrete hardware components, or combinations thereof. Control system 110 may be capable of performing the methods described herein, at least in part.

[0044] For example, the control system 110 may be able to determine when to operate at least a portion of the PMUT matrix 105 in a low frequency mode or a high frequency mode and control at least a portion of the PMUT matrix 105 according to the determination. Some implementations of display device 40 may include an interface system. The determination process can be done, at least in part, according to the input received from the interface system. The interface system may, for example, include one or more network interfaces, user interfaces, etc. The interface system may include one or more serial bus (USB) interfaces or similar interfaces. The interface system can include wireless or wired interfaces.

[0045] Figure 2 is a graph showing examples of frequency ranges for PMUT excitation. In Figure 2, the horizontal axis indicates potential excitation frequencies according to a logarithmic scale, and the vertical axis corresponds to a typical output voltage (Vout) of one or more PMUT elements in a PMUT matrix. In this example, a low frequency mode corresponds to a frequency range between about 50 kHz and 400 kHz and a high frequency mode corresponds to a frequency range between about 5 MHz and 50 MHz. low frequency mode and/or high frequency mode can correspond to different frequency ranges. In some of these implementations, the low frequency mode can correspond to a frequency range from about 50 kHz to 200 kHz and the high frequency mode can correspond to a frequency range from approximately 1 MHz to 25 MHz. Alternatively, or in addition , in some implementations, the PMUT matrix may be configurable to operate in a mid-frequency mode that corresponds to a frequency range between the low-frequency range and the high-frequency range (e.g., about 200 kHz to about 1 MHz). When operating in medium frequency mode, the equipment may be able to provide touch sensor functionality and gesture detection capability, but with slightly less resolution than high frequency mode.

[0046] Referring again to Figure 1, A, in some implementations, when the control system operates at least a portion of the PMUT array 105 in low frequency mode, the display device 40 may be able to emit sound waves that are capable of relatively greater air penetration than when display device 40 is operating in high frequency mode. In some instances, such lower frequency sound waves may be transmitted through multiple overlapping layers, such as a cover glass, a touchscreen, a display matrix, a backlight, and/or other layers that may vary by implementation. . In some implementations, lower frequency sound waves may be transmitted through one or more holes in the glass cover or lens of the display cover. Various configurations are disclosed here.

[0047] In some implementations, a port may be opened through one or more overlying layers to optimize coupling of the PMUT 105 array to air. Lower frequency sound waves can be transmitted through the air above the surface of the screen, reflected from one or more objects near the surface of the display device 40, transmitted through the air and back through the overlying layers, and detected by an ultrasonic receiver (eg from the PMUT 105 matrix). Consequently, when operating in low frequency mode, the display device 40 may be able to operate in a gesture detection mode, whereby gestures in free space close to the screen can be detected.

[0048] When operating in the high frequency mode, the display device 40 may be able to image at relatively higher resolution. Accordingly, display device 40 may be able to detect touch, fingerprint, stylus, and/or biometric information from an object such as a finger placed on the surface of display device 40. In some implementations, the high frequency mode can correspond to touch detection mode and/or a stylus detection mode. In some implementations, high frequency mode may correspond to fingerprint sensor mode.

[0049] In some cases, the control system 110 may be able to perform an authentication process based, at least in part, on the acquired fingerprint data while at least a portion of the PMUT matrix 105 operates in fingerprint sensor mode. fingerprint. The authentication process may involve providing an instruction, via the screen, to place at least one finger on a surface of the display device and receive, via at least a portion of the PMUT matrix 105, at least one fingerprint image. . In some implementations, the portion of the PMUT array 105 that the control system 110 controls to obtain the fingerprint image(s) may be placed in a peripheral zone of the display device 40, such as at an edge, side or corner of the screen 30.

[0050] The control system 110 may be able to determine received fingerprint data corresponding to the received fingerprint image(s). The term "fingerprint data", as used herein, includes data that can be used to characterize fingerprint minutiae, such as data corresponding to the types, locations, orientations and/or spacing of fingerprint minutiae. The fingerprint data may also include surface fingerprint pattern or image information and other biometric data associated with subsurface features.

[0051] The control system 110 may be able to compare the digital data received with the fingerprint data stored as part of the authentication process. In some implementations, the stored fingerprint data may be stored in a memory system of display device 40. The memory system may include one or more non-transient media, such as random access memory (RAM) and/or memory. read-only (ROM). The memory system may include one or more other suitable types of non-transient storage media, such as flash memory, one or more hard disk drives, etc. In some implementations, an interface system may include at least one interface between the control system 110 and the memory system. However, in some implementations, the authentication process may involve retrieving stored fingerprint data from another device through the interface system. For example, stored fingerprint data may reside on a server accessible over the Internet.

[0052] In some implementations, the control system 110 may be able to control the PMUT matrix 105 to operate in a medium frequency mode. In some implementations, the mid-frequency mode may correspond to operation over a frequency range of approximately 200 kHz to 1 MHz. Display device 40 may be capable of providing touch sensing functionality when control system 110 is controlling at least a portion of PMUT matrix 105 for operating in medium frequency mode. According to some implementations, the control system 110 may be able to determine when to operate at least a portion of the PMUT matrix 105 in the high frequency mode, the low frequency mode or the medium frequency mode; and controlling at least a portion of the PMUT matrix 105 to operate in the high frequency mode, the low frequency mode or the medium frequency mode, in accordance with the determination.

[0053] In some implementations, the control system 110 may be able to address at least a portion of the PMUT array 105 for wavefront beamforming, beam steering, receive-side beamforming, and/or selective reading of the returned signals. In some implementations, control system 110 may control an array of PMUT array transmitters 105 to produce wavefronts of a specific shape, such as flat, circular (spherical), or cylindrical wavefronts. Control system 110 can control the amplitude and/or phase of the PMUT array transmitter array 105 to produce constructive or destructive interference at desired locations. For example, control system 110 can control the amplitude and/or phase of the array of transmitters to produce constructive interference at one or more locations on display device 40 where a touch or gesture has been detected.

[0054] The generation and emission of plane ultrasonic waves (for example, plane waves) can be achieved by exciting and driving a large number of PMUT elements in the PMUT array 105 simultaneously, which can generate an ultrasonic wave with a substantially flat wavefront. Driving the individual PMUT elements in the PMUT array 105 can generate substantially spherical waves, in a forward direction, with the PMUT element serving as the source of the spherical waves. Alternatively, spherical waves can be generated by selecting and exciting an individual PMUT element (the center element), determining a first ring of PMUT elements around the center of the PMUT element, and driving the first ring in a delayed fashion, determining of a second ring of PMUT elements around the first ring and driving the second ring in an even more delayed fashion, and so on, as needed. The timing of the excitations can be selected to form a substantially spherical wavefront. Likewise, a cylinder wave can be generated by selecting and exciting a group of PMUT elements in a row, with the row of PMUT elements serving as the source of cylinder waves. Alternatively, cylinder waves can be generated by selecting and exciting one row of PMUT elements (the center row), determining and exciting adjacent rows of PMUT elements equidistant from the center row, with a controlled time delay, and so on. . The timing of the excitations can be selected to form a substantially cylindrical wavefront.

[0055] While an array of PMUT elements is excited simultaneously it can produce an ultrasonic plane wave that travels perpendicular to the PMUT array, phase control of the PMUT excitation can allow redirection of the plane wave in various directions depending on the amount of delay of phase. For example, if a phase delay of 10 degrees is applied to adjacent rows of PMUT elements that are positioned one tenth of a wavelength apart, then the wavefront will transmit a plane wave at an angle of about 15.5° from normal. Scanning a plane wave at different angles while detecting echoes (reflected portions) from an object positioned in front of the PMUT array can allow detection of the approximate shape, distance and position of the object. Consecutive determinations of object distance and position can allow determination of air gestures.

[0056] Other ways of transmitting beamforming can be used. For example, a set of PMUT elements in the PMUT array 105 can be fired so as to focus the wavefront of an ultrasonic wave at a particular location in front of the array. For example, the focused wavefront can be cylindrical or spherical, by adjusting the timing (eg, phase) of selected PMUT elements so that the wave generated from each selected PMUT element arrives at a predetermined location in the region in front of the PMUT array at a predetermined time. Focused wavefronts can generate significantly higher acoustic pressure at a point of interest, and the reflected signal from an object at the point of interest can be detected by operating the PMUT matrix in a receive mode. Wavefronts emitted from various PMUT elements can constructively interfere in the focal region. Wavefronts from multiple PMUT elements can destructively interfere with regions close to the focal region, providing even greater isolation of focused beam energy (amplitude) and increasing the signal-to-noise ratio of the return signal. Likewise, control of the phase in which detection occurs by various PMUT elements in the PMUT array 105 allows beamforming on the receiving side, in which the returning signals can be correlated with distance from a region in space and combined accordingly to generate an image of an object in the detection region. Controlling the frequency, amplitude and phase of waves transmitted from PMUT elements in the PMUT array 105 can also allow for beam shaping and beam forming. In some implementations, not all PMUT elements in the PMUT array need to be read for every operating mode, or for every frame. To save processing time and reduce battery consumption, feedback signals detected by a select group of PMUT elements can be read during acquisition. Control system 110 may be configured to address at least a portion of the PMUT matrix to at least one of wavefront beamforming, beam steering, receive-side beamforming, or selective readout of returned signals.

[0057] In some implementations, PMUT array 105 may include one or more active-matrix PMUT arrays. In such implementations, active matrix PMUT matrices can eliminate the large number of external interconnections that may be required for passive PMUT matrices by including active components (eg, TFTs) on the same substrate. Such active components may be part of the control system 110. Some of these active matrix PMUT matrices may include both a driver circuit and a detection circuit. In some of these implementations, the TFTs may be able to drive the PMUT elements of the PMUT array 105 in a synchronous manner. Alternatively or additionally, in some implementations, TFTs may be able to drive the PMUT elements of the PMUT matrix 105 in a phased manner. The active matrix may also include detection circuits for detecting feedback signals from the PMUT elements of the PMUT matrix 105.

[0058] In some examples, control system 110 may include row and column addressing circuitry. In some implementations, control system 110 may include multiplexer and/or demultiplexer circuitry, a local amplification circuit, analog-to-digital (A/D) conversion circuitry, and/or other control circuitry.

[0059] Figure 1B shows an example of a PMUT element. The PMUT 100a element can have one or more layers of piezoelectric material such as aluminum nitride (AIN) or lead zirconium titanate (PZT) in a piezoelectric layer that can be used to drive the PMUT element to generate ultrasonic waves or to detect waves. of received ultrasonics. The piezoelectric layer stack may include a bottom electrode layer 112, a piezoelectric layer 115, and an top electrode layer 114, with the piezoelectric layer 115 sandwiched between at least a portion of the bottom and top electrodes 112 and 114. or more dielectric layers 116 may provide electrical insulation for a metal interconnect layer 118, while allowing connections to lower and upper electrodes 112 and 114, respectively. The piezoelectric layer stack can be disposed on, above, or below the mechanical layer 130. An anchor structure 170 can support the PMUT membrane or diaphragm that is suspended over a cavity 120 and a substrate 160. The substrate 160 can have TFT circuitry for the triggering and detection of PMUT 100a and for generating a visual display. The stack of piezoelectric layer and mechanical layer 130 can flex, bend or vibrate in response to driving voltages Va and Vb applied across electrode layers 114 and 112, respectively. Vibrations of the PMUT element 100a can generate ultrasonic waves 190 at a frequency determined by the excitation frequency of the drive voltages. Ultrasonic waves striking the PMUT diaphragm can result in the generation of sensing voltages Va and Vb with flexion of the diaphragm. An underlying cavity 120 allows deviations of the PMUT element 100a without contacting the underlying substrate 160. The operating frequencies of the PMUT elements 100a can be adapted for high frequency operation, low frequency operation, medium frequency operation, or a combination of frequencies.

[0060] Figure 1C shows an example of a CMUT element. The CMUT element 100b can have a mechanical layer 130 supported above a cavity 120 and a substrate 160 by an anchor structure 170. The bottom electrode 112 on the substrate below the cavity and the top electrode 114 above the cavity 120 can be driven with an excitation voltage applied to terminals Va and Vb to generate ultrasonic waves 190. A potential difference between electrodes 112 and 114 causes an electrostatic force to be generated which draws the flexible diaphragm of the CMUT element 100b downwards towards the substrate. As electrostatic forces are attractive in this configuration if Va is greater than Vb or Vb is greater than Va, one of the electrodes may need to be tilted at a relatively high DC voltage to allow the small applied AC voltages to drive the diaphragm upwards. and down. Bias is also required to detect CMUT diaphragm deflections above cavity 120.

[0061] The PMUT 100a element, while slightly more complex to manufacture than the CMUT 100b element, generally requires lower operating voltages than the CMUT 100b element to generate similar acoustic energy. The PMUT 100a element does not suffer consequential crimping stresses for electrostatic devices like the CMUT 100b element, allowing for a fuller range of travel. In addition, CMUT 100b elements may require significantly higher bias voltages to allow detection of incoming ultrasonic waves.

[0062] Figure 3A shows an example of a PMUT matrix. In this example, the PMUT matrix 105 has been co-fabricated with the TFT circuit on the same substrate 305 which may be a glass or plastic substrate in some implementations. The TFT circuit may be part of the control system 110 of Figure 1A.

[0063] The TFT circuit may include row and column addressing electronic circuits, multiplexers, local amplification stages and control circuitry. In some examples, at least one array of TFTs includes circuitry for controlling the display. According to some implementations, at least one array of TFTs including circuitry for controlling the display can be disposed on a second substrate. In some implementations, at least one array of TFTs includes circuitry for controlling at least a portion of the PMUT array. According to some of these implementations, the circuit for controlling at least a portion of the PMUT matrix and the circuit for controlling the screen may be able to share a flexible cable.

[0064] Figures 3B-3F show several examples of circuit elements and PMUT elements. Figure 3B shows a single PMUT element 310 which is a pMUT element in this case. The PMUT matrix, like the PMUT matrix 105 of Figure 3A, can include various instances of the PMUT element 310 and/or other types of PMUT elements disclosed herein. In some examples, as described in more detail elsewhere here, at least some PMUT elements 310 of a PMUT matrix 105 may correspond with individual pixels of a screen 30.

[0065] In the example shown in Figure 3B, the PMUT element 310 can be configured both as a transmit element (Tx) and as a receive element (Rx). In this implementation, the TFT circuit element 315 may include a drive stage and a detection stage. Therefore, in this example, the TFT circuit element 315 is capable of causing the PMUT element 310 to emit ultrasonic waves. Furthermore, in this example, the TFT circuit element 315 is capable of detecting the responses from the same PMUT element 310, corresponding to the ultrasonic waves detected by the PMUT element 310.

[0066] In the implementation shown in Figure 3C, the PMUT element 310a is capable of functioning as an acoustic transmitter and a second PMUT element 310b is capable of functioning as an acoustic receiver. In this example, the TFT circuit element 315A is capable of controlling the PMUT element 310a and the TFT circuit element 315b is capable of providing the signals corresponding to the ultrasonic waves detected by the PMUT element 310b.

[0067] In some configurations, different PMUT 310 elements of the PMUT 105 array may be able to operate at low and high frequency (eg, for gesture detection and fingerprint/graphic pen detection). In the example shown in Figure 3D, PMUT element 310c is capable of functioning as a high-frequency acoustic transmitter and receiver (A-Freq), and PMUT element 310d is capable of functioning as a low-frequency acoustic transmitter and receiver (B frequency). Although in Figure 3D the PMUT element 310c and the PMUT element 310D are shown to be approximately the same size, in some examples, the PMUT element 310c may be smaller than the PMUT element 310d. In this implementation, TFT circuit element 315c is capable of controlling PMUT element 310c for high frequency operation and TFT circuit element 315D is capable of controlling PMUT element 310d for low frequency operation.

[0068] In other configurations, the same PMUT 310 element can be used for both low and high frequency operation. In the example shown in Figure 3E, the PMUT 310e element is capable of functioning as a high frequency sounder transmitter and receiver, and as a low frequency sounder transmitter and receiver. In this implementation, the TFT circuit element 315e is capable of controlling the PMUT element 310e for high frequency operation and for low frequency operation. In one mode of operation, the 315e TFT circuit element can control the 310E PMUT element to operate in either a high frequency mode (e.g., for touch, stylus, or fingerprint detection) or a low frequency mode (e.g., for example, by gesture or low-resolution touch detection). In another mode of operation, the TFT circuitry element 315e can control the PMUT element 310E to operate in an alternate mode, firing at a relatively high speed (e.g., with a rate of between about 5 and about 240 frames per second ) between high frequency and low frequency modes. In another mode of operation, the PMUT 310E element can be excited with a trigger signal having a high-frequency component and a low-frequency component, so that low-resolution gestures and high-resolution fingerprint imaging can be performed at the same time. Electronic filtering can be used to distinguish the return signals for the various frequencies.

[0069] Figure 3F shows an example of a PMUT matrix 105. The PMUT matrix 105 shown in Figure 3F may, for example, be a sub-matrix that is a portion of a larger PMUT matrix 105. In this example, the PMUT matrix 105 includes PMUT elements 310f and 310i. Here, the 315f TFT circuit element includes row and column addressing electronics to control the 310f-310i PMUT elements. In this example, the TFT circuit element 315q includes the multiplexer circuit and local amplification circuit.

[0070] Figure 4 shows another example of active components and a PMUT array on the same substrate. In this example, the PMUT matrix 105 and TFT circuit are both provided over common substrate 305 which may be glass or plastic in some implementations. Here, the TFT circuit includes row drivers 405a and 405b, as well as the data multiplexer and control circuit 410. Here, the row drivers 405a and 405b are capable of handling individual rows of the PMUT matrix 105. In some examples, the TFT circuits may be capable of handling the individual columns, rows, PMUT elements 310 and/or groups of PMUT elements 310 of the PMUT matrix 105.

[0071] In this example, an array of flexible pads 415 can provide connectivity with other components of a device. According to some implementations, the components shown in Figure 4 are part of a display device, such as the display device 40 of Figure 1A. Accordingly, the TFT circuit shown in Figure 4 can be part of the control system 110 of Figure 1A. In some implementations, control signals and/or data being input through flexible pads 415 may be sent from control system 110, and data being output through flexible pads 415 may be sent to control system 110, for example, via a flexible cable. In some examples, the TFT circuit and the circuitry for controlling the display may be able to share a flexible cable connected to the flexible pads 415. In some implementations, the TFT circuit (and/or other components of the control system 110) may be capable of addressing at least a portion of the PMUT matrix to at least one of wavefront beamforming, beam steering, receive-side beamforming, or selective readout of returned signals.

[0072] Figure 5A shows an example of a display device that includes a PMUT matrix. In this example, a single screen pixel 505 of display device 40 corresponds to a single PMUT element 310 of PMUT matrix 105. These implementations may be referred to herein as "in-cell" implementations. In some implementations, a PMUT element 310 may correspond with each screen pixel 505 on screen 30. In some implementations, PMUT elements 310 may be positioned in a pixel portion of screen 505, or in selected areas of screen 30 as close to a corner or edge of the active display area.

[0073] In this example, the screen pixel 505 includes a red subpixel 505a, a green subpixel 505b and a blue subpixel 505c. Other in-cell implementations may include 505 screen pixels with different numbers and/or colors of subpixels. Still other in-cell implementations may have 505 screen pixels that do not include subpixels, such as multi-state IMOD pixels, each of which may provide a range of colors.

[0074] In some high resolution implementations of the display device 40, the screen 30 may include 500 pixels having a spacing or pitch of 50 microns, which is approximately 500 dots or pixels per inch. In order to have a high enough resolution for fingerprint detection, fingerprint sensor arrays may also need to be spaced on the order of 500 dots or pixels per inch. Therefore, in some in-cell implementations a display device 40, as shown in Figure 5A, can provide a high resolution screen 30 and a PMUT matrix 105 having a sufficiently high resolution for fingerprint sensor functionality. .

[0075] In the in-cell implementation shown in Figure 5A, the PMUT elements 310 of the PMUT matrix 105 are positioned in substantially the same plane as the screen subpixels, so that a portion of the screen area is used by the PMUT elements. In such implementations, it is desirable for the PMUT elements 310 to be non-transparent or substantially non-transparent. In other in-cell implementations, a portion or all of each PMUT element 310 of PMUT array 105 may be positioned above or below one or more screen subpixels of screen pixels 505. In such implementations, it is desirable that PMUT elements 310 are transparent or substantially transparent.

[0076] According to some implementations, at least a portion of the PMUT matrix 105 can be arranged substantially behind the entire screen 30. Figure 5B shows an example of a display device that has a PMUT matrix that is coextensive with a matrix of screen pixels. In this example, PMUT matrix 105 is positioned behind screen 30: screen pixels 505 are between PMUT elements 310 and a viewer 510. In this example, PMUT matrix 105 is disposed on substrate 305, which may be formed of any suitable material. For implementations in which light will be transmitted through substrate 305 (for example, if substrate 305 is positioned between screen 30 and a backlit panel), substrate 305 can be a transparent or substantially transparent glass, plastic, or other material. However, if it is not necessary for light to be transmitted through the substrate 305 (for example, if the substrate 305 is positioned below a backlit panel or if the screen 30 is an emissive screen, such as a light-emitting diode screen (OLED)), the substrate 305 need not be formed of a transparent or substantially transparent material. Here, screen 30 includes an array of screen pixels 505 on a substrate 515, which may be a glass or plastic substrate in some implementations.

[0077] The PMUT array 105 may include various types of PMUT elements 310, depending on the particular implementation. In some implementations, the PMUT matrix 105 may include PMUT elements 310 configurable as low frequency emitters and/or receivers for ultrasonic gesture detection. In some implementations, the PMUT matrix 105 may include configurable PMUT elements 310 as high frequency emitters and/or receivers, for example, fingerprint detection, stylus and/or other ultrasonic biometric detection. In some implementations, the PMUT matrix 105 may include PMUT elements 310 configurable as both low frequency and high frequency emitters and/or receivers, for example, for gesture detection and biometric detection. In some configurations, the PMUT matrix 105 may include PMUT elements 310 that are capable of button functionality, which may be authenticate button functionality and/or deauthenticate button functionality. In some implementations, the PMUT matrix 105 may include PMUT elements 310 configured to operate in a medium frequency mode. When operating in mid-frequency mode, display device 40 may be able to provide gesture sensing capability and/or touch sensor functionality, but with slightly less resolution than operating in low-frequency mode or high frequency.

[0078] In the example shown in Figure 5B, the substrate 305 and the substrate 515 can be joined by means of a coupling agent 520. Here, the substrate 515 and the cover glass 525 are joined by means of an adhesive 530. The agent coupling element 520 can include silicone, an adhesive such as epoxy, a pressure sensitive adhesive (PSA), or other suitable material with acoustic and optical properties. For example, coupling agent 520 may have little or substantially zero acoustic impedance difference with substrate 305 and substrate 515. Similarly, adhesive 530 may have little or substantially zero acoustic impedance difference with substrate 515 and substrate 525. Preferably, there is substantially no air gap between PMUT matrix 105 and cover glass 525.

[0079] Figure 5C shows an exemplary stack for a display device that includes an LCD screen and a PMUT matrix. For the sake of simplicity, the sticky layers of the stack are not shown. Here, the display device 40 may include a PMUT matrix 105, a backlight panel 532, an LCD screen module 535, a touch panel 540, and a glass cover 525.

[0080] In this example, the PMUT matrix 105 may include a pMUT matrix and TFT circuit on a substrate 305. Here, the backlight panel 532 includes a backlight substrate, a reflector film, a diffuser film, and a gloss enhancement film ( BEF). In this implementation, the LCD display module 535 includes polarization layers, a TFT substrate, TFT circuitry, liquid crystal material, color filters, and a color filter glass. In this example, touch panel 540 includes a touch panel substrate, which is formed of glass in this case, as well as transparent electrode layers, which are the indium tin oxide (ITO) layers in this implementation. In some implementations, the TFT circuit for controlling the PMUT matrix 105 and the TFT circuit for controlling the LCD display module 535 may be able to share a flex cable.

[0081] Figure 5D shows an exemplary stack for a display device that includes an OLED screen and a PMUT matrix. In this example, the stack is substantially simpler than that shown in Figure 5C. The OLED screen module 545, which includes a TFT substrate, TFT circuit and OLED material, is substantially simpler than the LCD screen module 535 shown in Figure 5C. Furthermore, because the OLED 545 display module is an emissive display module, no backlight panel is required. In some implementations, the TFT circuit for controlling the PMUT matrix 105 and the TFT circuit for controlling the LCD display module 545 may be able to share a flex cable.

[0082] As mentioned above, having a "full size" PMUT matrix 105 that is co-extensive with a variety of screen pixels can provide several potential advantages. However, a full-size PMUT matrix 105 attached to the rear of a screen 30 can substantially increase the expense and increase the thickness of the display device.

[0083] However, in some examples, at least a portion of the PMUT matrix 105 may be arranged behind only a portion of the screen. Figure 6A shows an example of a display device that includes a PMUT matrix behind only a portion of a screen. The elements shown in Figure 6A are substantially similar to those shown in Figure 5B. However, in the example of Figure 6A, the area 605 occupied by the PMUT matrix 105 is substantially smaller than the area 610 occupied by the screen 30.

[0084] In some implementations, the PMUT matrix 105 may include configurable PMUT elements 310 as high-frequency emitters and/or receivers, for example, fingerprint detection, pen graph and/or other ultrasonic biometric detection. In some of these implementations, PMUT matrix 105 may correspond to a fingerprint sensor area or ultrasonic touchpad area of display device 40. In some implementations, PMUT matrix 105 may include PMUT elements 310 configurable as low frequency emitters and /or receivers for ultrasonic gesture detection. In these implementations, display device 40 may include multiple areas 605 each of which correspond to a PMUT matrix 105. In some implementations, PMUT matrix 105 may include PMUT elements 310 configurable as both low frequency and high frequency emitters and/or receivers, for example, for gesture detection and biometric detection. In some implementations, the PMUT matrix 105 may include PMUT elements 310 configured to operate in a mid-frequency mode, for example, for lower resolution gesture detection and/or touch sensor functionality.

[0085] According to some implementations, at least a portion of the PMUT matrix 105 may be arranged in a peripheral area of the screen 30. A control system, such as the control system 110 of Figure 1A, may be able to control a portion of the PMUT matrix 105 that is disposed in the peripheral area of the screen 30 for biometric sensor functionality (such as fingerprint sensor functionality), touchpad or signature pad functionality (eg, stylus), gesture detection functionality, and /or button functionality.

[0086] Figures 6B-D show an example of a display device that includes a PMUT matrix near a periphery of a screen. As shown in Figure 6B, a display device 40 (a portion of which is shown) may include a screen 30 formed on a substrate 660 along with a PMUT matrix 105. The screen 30 may be optically and mechanically coupled to a cover lens or cover glass 630. One or more holes 180 may be formed in the cover glass 630 to allow transmission and reception of acoustic and ultrasonic waves 190. The holes 180 may include, for example, one or more circular, square or rectangular, elongated holes, tapered holes or slots. Figure 6C shows a portion of a display device 40 with a screen 30 and a PMUT matrix 105 formed on a substrate 660, with the assembly optically and mechanically coupled to a cover glass 630 that has one or more holes 180 formed therein. Holes 180 may be filled with an acoustic coupling material 186 such as a silicone gel to provide some environmental protection for the PMUT array 105 while also allowing transmission and reception of ultrasonic waves 190. Figure 6D shows a thin covering or coating 188 disposed over a mating material 186 positioned within a hole 180 formed in a cover glass 630. An adhesive layer 184 can connect a protective membrane 182 to the covering glass 630, while the protective membrane can be bonded to the matrix PMUT 105 which may be formed on substrate 660 along with visual display 30. Coating 188 may be a hard coating such as diamond-like carbon (DLC), an acrylic, or other suitable coating material that is sufficiently compatible for wave transmission. ultrasonic beams 190, providing additional environmental protection for the PMUT matrix 105, associated circuitry and screen 30 of display device 40.

[0087] Figures 7A-7F show examples of PMUT arrays arranged in peripheral areas of a screen. In these examples, the TFT circuit for the screen and the TFT circuit for the PMUT 105 matrices are arranged on the same substrate (eg common).

[0088] In Figure 7A, for example, the TFT circuit 705 for the PMUT matrix 105 is disposed on the same substrate (the substrate 305) as the TFT circuit 730 for a screen. The screen can, for example, be an LCD screen or an OLED screen. Here, the data multiplexer and control circuit 410 can be connected to the flexible pads through the fanout region 710. In this example, the PMUT matrix 105 is a PMUT matrix configurable as a fingerprint sensor or ultrasonic touch sensitive element. However, in alternative implementations at least a portion of the PMUT matrix 105 may be configurable for other functionality, such as gesture detection functionality and/or button functionality. In this implementation, PMUT matrix 105 is disposed in a corner of display device 40 outside an active display area. The display area can be approximately coextensive with the area of the TFT circuit 730 shown in Figure 7A. In some implementations, one or more flexible pads on substrate 305 may provide the electrical connection between TFT circuit 705 and external circuitry. One or more flexible cables may be attached or electrically connected to at least a portion of the flexible pads 415 on the substrate 305. For example, a flexible cable may be shared between circuitry for controlling at least a portion of the PMUT matrix 105 and TFT circuit 730 to control the screen.

[0089] In Figure 7B, the TFT circuit 705 for the PMUT matrix 105 is disposed on the same substrate 305 as the TFT circuit 730 for a screen. In this example, PMUT matrix 105 includes PMUT sub-matrices 105a and 105b. In this implementation, the PMUT 105a-b sub-arrays are laid out outside the active display area. In this implementation, PMUT sub-arrays 105a and 105b may extend along at least a portion of sides 715a and 715b, respectively, of display device 40. For example, a one-dimensional string of low-frequency PMUT elements may be positioned along a first side 715a of display device 40, and another string of low-frequency PMUT elements may be positioned along a second side 715b of display device 40. In another example, a first PMUT element may be positioned along a second side 715b of display device 40. along first side 715a near a corner of display device 40 and a second PMUT element may be positioned along first side 715a near a second corner of display device 40. A third and fourth PMUT element may be positioned along of the second side 715b near a third and fourth corner of the display device 40. PMUT elements configured near each of the four corners of the display device 40 can allow for gesture detection through triangulation of a finger, hand or other object positioned above display device 40. More than one PMUT element in a sub-array can be configured at each corner or along one or more sides of display device 40. In some examples, PMUT sub-arrays 105a and 105b can be configurable for gesture detection. In this implementation, PMUT sub-arrays 105F may be driven by TFT circuit 705 which may be disposed in two corners of display device 40. In alternative implementations, TFT circuit 705 and PMUT matrices 105 may be configurable for other functionality, such as functionality fingerprint detection and/or button functionality.

[0090] In Figure 7C, the PMUT matrix 105 includes PMUT sub-arrays 105a, 105b and 105f, all of which are disposed outside the active area of the screen. As in the implementation shown in Figure 7B, PMUT sub-arrays 105a and 105b may extend along a portion or all sides 715a and 715b, respectively, of display device 40. In some examples, PMUT sub-arrays 105a and 105b may be configurable for gesture detection. In this implementation, the 105f sub-array can be configurable for either fingerprint sensor or ultrasonic touchpad functionality. Accordingly, in this example, the TFT circuit 705 for the PMUT matrix 105 may include the TFT circuit for the fingerprint sensor and gesture detection functionality.

[0091] In Figure 7C, the PMUT matrix 105 includes PMUT sub-arrays 105g-105i, all of which are disposed outside the active area of the screen. Here, the fanout region 710 and the flex pads 415 are offset to allow space for the PMUT 105g-105i sub-arrays. In this implementation, sub-arrays 105g-105i may be configurable for button functionality. Accordingly, in this example, the TFT circuit 705 for the PMUT matrix 105 may include the TFT circuit for button functionality. Control button functionality may involve some aspect of display device 40, with or without authentication functionality. Therefore, these buttons can be referred to as “authentication” buttons or “de-authentication” buttons. The PMUT sub-arrays for authentication buttons can include substantially more PMUT elements 310 than the PMUT sub-arrays for de-authentication buttons, to allow higher resolution imaging of fingerprints. In some examples, a de-authenticate button may correspond with a single PMUT element 310, a small (e.g., two by two) array of PMUT elements 310, or a larger array of PMUT elements 310.

[0092] In some implementations, at least one of PMUT sub-arrays 105g-105i may be configured for authentication button functionality, and at least one of PMUT sub-arrays 105g-105i may be configured for button functionality of non-authentication. In such implementations, TFT circuitry 705 for PMUT matrix 105 may include TFT circuitry for authentication button functionality (e.g., fingerprint sensor functionality) and de-authentication button functionality. In some implementations, an authenticate button can also serve as a de-authenticate button.

[0093] Figure 7E includes PMUT sub-arrays 105j and 105k, each of which may be located in a corner of display device 40. In this example, PMUT sub-array 105j is capable of fingerprint sensor functionality and the PMUT 105K sub-matrix is capable of button functionality. Therefore, in this example, TFT circuit 705a for PMUT matrix 105 includes TFT circuitry for fingerprint sensor functionality and TFT circuit 705b includes TFT circuitry for button functionality, which can be authentication button functionality or the de-authenticate button.

[0094] Figure 7F includes PMUT sub-arrays 105a, 105b and 1051-105n. As in the implementation shown in Figure 7B, PMUT sub-arrays 105a and 105b extend along a portion or all sides 715a and 715b, respectively, of display device 40. In this example, PMUT sub-arrays 105a and 105b are configurable for gesture detection.

[0095] In this implementation, the PMUT sub-array 1051 is capable of providing fingerprint sensor functionality and gesture detection functionality. Here, the PMUT 105m sub-matrix is capable of button functionality. In this example, the PMUT 105n sub-array is capable of providing both gesture detection functionality and button functionality. Accordingly, in this example, the TFT circuit 705 for the PMUT matrix 105 includes the TFT circuit for the fingerprint sensor and gesture detection functionality. Here, the TFT circuit 705d includes TFT circuits for button functionality, which can be authentication button functionality or de-authentication button functionality, as well as TFT circuits for gesture detection functionality.

[0096] In view of the foregoing, it will be apparent to those skilled in the art that various other configurations are within the scope of the present disclosure. For example, some alternative implementations may include PMUT sub-arrays arranged at each corner of the screen periphery that are capable of providing gesture detection functionality. PMUT sub-arrays can provide full capability to send and receive ultrasonic signals for gesture detection. In some implementations, one or more microphones on a mobile device may be used to receive ultrasonic waves generated by PMUT elements to further aid in gesture detection. Typical microphones have a limited audio range (eg, 100 to 10,000 Hz response), while better performing audio microphones may be sensitive to ultrasonic frequencies up to 180 kHz or 200 kHz. Microphones can be placed in a variety of locations on the mobile device, such as near the bottom of the device's face. High performance phones may have multiple microphones on the front and/or back of the phone case for increased audio clarity and noise cancellation. Microphones with a high frequency response can help with gesture detection, along with PMUT elements that operate in a receive mode. Therefore, in some alternative implementations, at least some of the receivers used for gesture detection may be microphones on a display device.

[0097] In some implementations, a touch panel and at least portions of the PMUT 105 matrix may share a common flex cable. In accordance with some implementations, a touch panel substrate or cover glass may have additional electrodes for the topside electrical connections to at least a portion of the PMUT array 105 located at the periphery of a display area. In some of these implementations, these additional electrodes may provide electrical connectivity with at least a portion of a control system.

[0098] Some such implementations may have a control system that includes a separate TFT circuit disposed on separate substrates for the screen and for at least a portion of the PMUT matrix 105, which may be disposed on a periphery of the screen. In some of these implementations, these additional electrodes may be configured for electrical connectivity to circuits, such as TFT circuits, with a portion of the PMUT array 105 configured for fingerprint sensor functionality and/or gesture detection functionality. In some of these implementations, these additional electrodes may be configured for electrical connectivity to circuits, such as TFT circuits, with a portion of the PMUT matrix 105 configured for button functionality (eg, authenticate or de-authenticate button functionality).

[0099] Figures 8A and 8B show sample system block diagrams illustrating a display device that includes at least one PMUT matrix as described herein. The display device 40 can be, for example, a cellular or mobile phone. However, the same components of display device 40 or slight variations thereof are also illustrative of various types of display devices, such as televisions, computers, tablets, e-readers, handheld devices, and portable media devices.

[0100] The display device 40 includes a housing 41, a screen 30, an antenna 43, a speaker 45, an input device 48 and one or more microphones 46. The housing 41 may be formed from any one of a variety of manufacturing processes including injection molding and vacuum molding. Furthermore, housing 41 can be made from any of a variety of materials, including, but not limited to: plastic, metal, glass, rubber, and ceramic, or a combination thereof. The wrapper 41 may include removable portions (not shown) that may be interchanged with other removable portions of a different color, or with different logos, images or symbols.

[0101] Screen 30 can be any of a variety of screens, including a bistable or analog screen, as described herein. The display 30 can also include a flat panel display, such as plasma, EL, OLED, STN LCD, or TFT LCD, or a non-flat panel display, such as a CRT or other tube device. Additionally, screen 30 may include an interferometric modulator (IMOD) based screen.

[0102] The components of the display device 40 are schematically illustrated in Figure 8B. Display device 40 includes housing 41 and may include additional components at least partially encased therein. For example, display device 40 includes a network interface 27 that includes an antenna 43 that can be coupled to a transceiver 47. Network interface 27 can be a source for image data that can be displayed on display device 40 Therefore, network interface 27 is an example of an image source module, but processor 21 and input device 48 can also serve as an image source module. Transceiver 47 is connected to a processor 21, which is connected to conditioning hardware 52. Conditioning hardware 52 may be capable of conditioning a signal (such as a filter or otherwise manipulating a signal). The conditioning hardware 52 can be connected to a speaker 45 and a microphone 46. The processor 21 can also be connected to an input device 48 and a trigger controller 29. The trigger controller 29 can be coupled to a frame buffer 28, and to a matrix driver 22, which in turn may be coupled to a display matrix 30. One or more elements on display device 40, including elements not specifically depicted in Figure 8B, may be capable of functioning as a memory device and be able to communicate with the processor 21. In some implementations, a power supply 50 can supply power to virtually all components of the specific display device design 40.

[0103] In this example, the display device 40 may also include one or more two-dimensional linear or branched PMUT arrays 77. In some implementations, at least a portion of the PMUT array 77 may be disposed substantially behind the screen 30. In some of these implementations , a PMUT matrix 77 may be disposed behind only part of the screen 30, whereas in other implementations a PMUT matrix 77 may be disposed behind substantially the entire area of the screen 30. In some implementations, at least a portion of the PMUT matrix 77 may be included within one or more display pixels of display matrix 30. Processor 21 may be a portion of a control system that is capable of controlling PMUT matrix 77 (at least in part), such as described here. Accordingly, a control system 110 as described elsewhere herein may include processor 21 and/or other elements of display device 40, such as TFTs.

[0104] In some implementations, the processor 21 (and/or another element of the control system 110) may be able to provide input to control the display device 40 in accordance with one or more gestures detected when the PMUT matrix 77 it is running in a low frequency mode. In some implementations, processor 21 (and/or another element of control system 110) may be capable of providing input to control display device 40 in accordance with one or more designated touch locations and/or motions when the matrix PMUT 77 is working in a medium frequency mode. In some implementations, processor 21 (and/or another element of control system 110) may be capable of providing input to control display device 40 in accordance with one or more fingerprint data or pen input data. graphics determined when the PMUT 77 matrix is running in a high frequency mode.

[0105] The network interface 27 includes the antenna 43 and the transceiver 47 so that the display device 40 can communicate with one or more devices over a network. Network interface 27 may also have some processing resources to alleviate, for example, the data processing requirements of processor 21. Antenna 43 may transmit and receive signals. In some implementations, antenna 43 transmits and receives RF signals in accordance with the IEEE 16.11 standard, including IEEE 16.11(a), (b), or (g), or the IEEE 802.11 standard, including IEEE 802.11a, b , g, n, and other implementations thereof. In some other implementations, the antenna 43 transmits and receives the RF signals in accordance with the Bluetooth standard. In the case of a cellular telephone, antenna 43 may be designed to receive code division multiple access (CDMA), FDMA (FDMA), TDMA (TDMA), Global System for Mobile Communications (GSM), General Packet/GSM (GPRS), GSM Enhanced Data Environment (EDGE), Truncated Radio Terrestrial (TETRA), Broadband CDMA (W-CDMA), Evolution Data Enhanced (EV-DO), 1xEV-DO, EV -DO Rev A, EV-DO Rev B, High Speed Packet Access (HSPA), High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), Evolved High Speed Packet Access (HSPA+), Long Term Evolution (LTE), AMPS, or other known signals that are used to communicate within a wireless network, such as a system using 3G, 4G, or 5G technology. Transceiver 47 can pre-process signals received from antenna 43 so that they can be received by and further manipulated by processor 21. Transceiver 47 can also process signals received from processor 21 so that they can be transmitted from display device 40 via antenna 43.

[0106] In some implementations, the transceiver 47 can be replaced by a receiver. Furthermore, in some implementations, the network interface 27 may be replaced by an image source, which may store or generate image data to be sent to processor 21. Processor 21 may control the overall operation of the display device. 40. Processor 21 receives data, such as compressed image data, from network interface 27, or an image source, and processes the data into raw image data or a format that can be easily transformed into image data. gross. Processor 21 may send the processed data to trigger controller 29 or frame buffer 28 for storage. Raw data typically refers to information that identifies image features at each location within an image. For example, these image characteristics might include color, saturation, and grayscale level.

[0107] The processor 21 may include a microcontroller, PCU or logic unit to control the operation of the display device 40. The conditioning hardware 52 may include amplifiers and filters for transmitting signals to the speaker 45, and for receiving signals from from microphone 46. Conditioning hardware 52 may be discrete components within display device 40, or may be incorporated within processor 21 or other components.

[0108] The driver controller 29 can obtain the raw image data generated by the processor 21 either directly from the processor 21 or from the frame buffer 28 and can re-format the raw image data appropriately for high-speed transmission to matrix driver 22. In some implementations, driver controller 29 can re-format the raw image data into a data stream, which has a similar raster format, so that it has an order of adequate time for scanning across the display matrix 30. Next, the trigger controller 29 sends the formatted information to the matrix controller 22. Although a trigger controller 29, such as an LCD controller, is often associated with system processor 21 as a stand-alone integrated circuit (IC), such controllers can be implemented in many ways. For example, the controllers may be built into processor 21 as hardware, built into processor 21 as software, or fully integrated into hardware with matrix driver 22.

[0109] The matrix driver 22 can receive the formatted information from the driver controller 29 and can re-format the video data into a parallel set of waveforms that are applied many times per second to hundreds and sometimes , thousands (or more) of links coming from the x-y matrix of display element screens

[0110] In some implementations, the trigger controller 29, the matrix trigger 22, and the screen 30 are suitable for any of the types of screens described herein. For example, the trigger controller 29 can be a conventional screen controller or an IMOD display element controller, such as a multi-state IMOD (MS-IMOD display element controller). Furthermore, the matrix controller 22 can be a conventional trigger or a bistable screen trigger (such as an MS-IMOD display element controller). Furthermore, the screen 30 can be a conventional matrix screen or a bistable display matrix (such as a screen including a matrix of IMOD display elements). In some implementations, driver controller 29 may be integrated with matrix driver 22. Such an implementation may be useful in highly integrated systems, for example, cell phones, handheld electronic devices, watches or small area displays.

[0111] In some implementations, input device 48 may be capable of allowing, for example, a user to control the operation of display device 40. Input device 48 may include a keyboard, such as a QWERTY keyboard or a keyboard. telephone, a button, a switch, an oscillator, a touch screen, a touch screen integrated with the display matrix 30, or a pressure or heat sensitive membrane. Microphone 46 may be capable of functioning as an input device for display device 40. In some implementations, voice commands through microphone 46 may be used to control operations of display device 40.

[0112] Power supply 50 may include a variety of energy storage devices. For example, the power source 50 can be a rechargeable battery such as a nickel cadmium battery or a lithium ion battery. In implementations that use a rechargeable battery, the rechargeable battery may be chargeable using energy from, for example, a wall outlet or from a photovoltaic device or array. Alternatively, the rechargeable battery can be remotely recharged. The power supply 50 can also be a renewable energy source, a capacitor, or a solar cell, which includes a plastic solar cell or solar cell ink. Power supply 50 may also be capable of receiving power from a wall outlet.

[0113] In some implementations, the programmability of the control resides in the actuator controller 29, which may be located in various places on the electronic display system. In some other implementations, the control programmability resides in the matrix driver 22. The above-described optimization can be implemented on any number of hardware and/or software components and in various configurations.

[0114] As used here, a phrase referring to “at least one of a list of items refers to any combination of those items, including individual members. As an example, "at least one of: a, b, or c" is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

[0115] The various illustrative logic, blocks, modules, circuits, and algorithm logic processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally in terms of functionality and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware or software depends on the application and specific design limitations imposed on the overall system.

[0116] The hardware and data processing apparatus used to implement the various logic, modules and illustrative logic circuits described in connection with the aspects presented in the present invention can be implemented or executed with a single processor or several general purpose chips, a digital signal processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination designed to perform the functions described here. A general purpose processor can be a microprocessor or any conventional processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, for example a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors together with a DSP core, or any other type of configuration. In some implementations, specific processes and methods may be performed by circuitry that is specific to a given function.

[0117] In one or more aspects, the described functions can be implemented in hardware, digital electronic circuits, software, firmware, including the structures disclosed in this specification and their structural equivalents, or in any combination thereof. The subject implementations described herein may also be implemented as one or more computer programs, i.e., one or more computer program instruction modules, encoded on computer storage media for executing or controlling the operation of the data processing apparatus.

[0118] If implemented in software, the functions may be stored in or transmitted through one or more instructions or code on a computer-readable medium, such as a non-transient medium. The processes of a method or algorithm described herein may be implemented in a processor-executable software module that may reside on computer-readable media. Computer-readable media include computer storage media and communication media, including any medium that can be enabled for transferring a computer program from one place to another. Storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, non-transient media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be Used to store desired program code in the form of instructions or data structures that can be accessed by a computer. Also, any connection can properly be called a computer-readable medium. Disk and floppy disk as used herein include compact disk (CD), laser disk, optical disk, digital versatile disk (DVD), floppy disk and Blu-ray disk where floppy disks generally play data magnetically while disks play data optically with lasers. Combinations of the foregoing should also be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on machine-readable media and computer-readable media, which may be incorporated into a computer program product.

[0119] Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other implementations without departing from the spirit and scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to accord with the widest scope consistent with this disclosure, the principles and novel features described herein. Furthermore, a person skilled in the art will easily understand, that the terms "superior" and "inferior", "above" and "bso" and "superimposed" and "underlying" are sometimes used to facilitate the description of the figures, and indicate Relative positions correspond to the orientation of the figure on a properly oriented page, and may not reflect the proper orientation of the device as implemented.

[0120] Some features that are described in this descriptive memory, in the context of separate implementations can also be implemented in combination in a single application. On the other hand, various features that are described in the context of a single implementation may also be implemented in several implementations separately or in any suitable sub-combination. Furthermore, although features may be described above as acting in certain combinations and still initially claimed as such, one or more features of a claimed combination may in some cases be excised from the combination, and the claimed combination may be directed towards a subcombination or variation of a subcombination.

[0121] Likewise, while operations are represented in the drawings in a particular order, these should not be understood as requiring that these operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In addition, the drawings may schematically represent one or more exemplary processes in the form of a flowchart. However, other operations that are not described can be incorporated in the exemplary processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously with, or between any of the illustrated operations. In certain circumstances, multithreading and parallel processing can be advantageous. Furthermore, the separation of the various system components in the implementations described above should not be construed as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together into a single software product. or packaged in various software products. Furthermore, other implementations are within the scope of the following claims. In some cases, the actions listed in the claims can be performed in a different order and still achieve desirable results.

Claims (14)

1. Display device (40) comprising: a substrate; a display (30) coupled to the substrate; a piezoelectric micromechanical ultrasonic transducer array, PMUT, next to the display (105), wherein at least a portion of the PMUT array resides on the substrate; a plurality of thin-film transistors, TFTs, at least a first array of TFTs residing in the substrate and including circuitry for controlling the display, and at least a second array of TFTs residing in the substrate and including circuitry for controlling at least a portion of the PMUT array ; and a control system (110); and the control system characterized by being capable of: making a determination of the possibility of operating at least a portion of the PMUT array in at least one of a low frequency mode or a high frequency mode; and controlling at least a portion of the PMUT array to operate in at least one of a low frequency mode or a high frequency mode, as determined. 2. Display device according to claim 1, characterized in that it additionally includes an interface system, whereby the determination is made, at least in part, according to the input received from the interface system; and preferably, wherein the low frequency mode corresponds to a frequency range of approximately 50 kHz to 200 kHz; or wherein the low frequency mode corresponds to a gesture detection mode, wherein free space gestures close to the display can be detected; or wherein the high frequency mode corresponding to a frequency range of approximately 1 MHz to 25 MHz. Display device according to claim 1, characterized in that the high-frequency mode corresponds to a fingerprint sensor mode or a stylus-type detection mode; and, preferably, wherein the control system is capable of performing an authentication process based at least partially on fingerprint data acquired while the PMUT array operates in fingerprint sensor mode; and preferably further includes a memory system wherein the authentication process involves: providing a prompt, via the display, to place at least one finger on a surface of the display device; receiving, by means of at least a portion of the PMUT array, at least one fingerprint image; determining received fingerprint data corresponding to the at least one fingerprint image; and comparing the received fingerprint data with fingerprint data in the memory system. 4. Display device according to claim 1, characterized in that the control system has the ability to: make a determination of the possibility of operating at least a portion of the PMUT array in high-frequency mode, in low-frequency mode or in a medium frequency mode; and controlling at least a portion of the PMUT array to operate in the high frequency mode, the low frequency mode or the medium frequency mode, in accordance with the determination; and, preferably, wherein the display device is capable of providing touch sensor functionality when the control system is controlling at least a portion of the PMUT array to operate in the medium frequency mode; or where the medium frequency mode corresponds to a frequency range of approximately 2kHz to 1 MHz. 5. Display device according to claim 1, characterized in that the control system has the ability to control first PMUT elements of the PMUT array to operate in low-frequency mode and second PMUT elements of the PMUT array to operate in low-frequency mode. high frequency; or wherein the control system is capable of controlling a PMUT element of the PMUT array to operate in the low frequency mode and to operate in the high frequency mode. 6. Display device according to claim 1, characterized by the PMUT array being a piezoelectric micromechanical ultrasonic transducer array, pMUT, or a capacitive micromechanical ultrasonic transducer array, cMUT. 7. Display device according to claim 1, characterized in that the control system is capable of addressing at least a portion of the PMUT array for at least one of wavefront beamforming, beam steering, beamforming on the receiving side or selective reading of returned signals; and, preferably, wherein the control system is capable of addressing at least a portion of the PMUT array to produce wavefronts of substantially flat, spherical or cylindrical shape; or wherein the control system is capable of addressing at least a portion of the PMUT array to produce constructive or destructive interference at at least one location. 8. Display device according to claim 1, characterized in that the control system has the ability to excite PMUT elements of the PMUT array and detect response through PMUT elements; wherein the control system is capable of controlling a first PMUT element of the PMUT array as an acoustic transmitter and a second PMUT element of the PMUT array as an acoustic receiver. 9. Display device according to claim 1, characterized in that at least a portion of the PMUT array is an active matrix PMUT array; and preferably wherein the active matrix PMUT arrangement includes driver circuitry and pickup circuitry; or wherein the active matrix PMUT array includes at least one row and column of addressing circuitry, demultiplexer circuitry, local amplification circuitry, or analog-to-digital conversion circuitry. 10. Display device according to claim 1, characterized in that at least a portion of the PMUT array is arranged behind only a portion of the display; wherein at least a portion of the PMUT array is disposed in a peripheral area of the display; or wherein the control system is capable of controlling a portion of the PMUT array that is disposed in the peripheral area of the display for at least one of fingerprint sensor functionality, signature pad functionality, stylus pen detection functionality , gesture detection functionality or button functionality; or wherein at least a portion of the PMUT array is disposed substantially behind the entire display. 11. Display device according to claim 1, characterized in that at least a portion of the PMUT array is arranged on a substrate; and preferably wherein the substrate is a glass substrate; and, more preferably, wherein at least one array of thin film transistors, TFTs, is also disposed on the substrate. 12. Display device according to claim 11, characterized in that at least one array of TFTs includes circuitry for controlling the display; or wherein the at least one array of TFTs includes circuitry for controlling at least a portion of the PMUT array; and, preferably, wherein the circuitry for controlling at least a portion of the PMUT array and the circuitry for controlling the display are capable of sharing a flexible cable. 13. The display device of claim 11, characterized in that at least one array of TFTs includes circuitry for controlling at least a portion of the PMUT array and wherein at least one array of TFTs includes circuitry for controlling at least one portion of the PMUT array. controlling the display is disposed on a second substrate; and preferably further comprising: a cover glass; electrodes disposed in the cover glass, the electrodes being configured for electrical connections on the upper side of the circuitry for controlling at least a portion of the PMUT array; and, more preferably, wherein the electrodes are configured for connection with circuitry for at least one PMUT element that is disposed at a periphery of the display. 14. Display device according to claim 1, characterized in that a single PMUT element of the PMUT array corresponds to a single pixel of the display.