WO2014165662A2

WO2014165662A2 - Portable electronic devices with integrated imaging capabilities

Info

Publication number: WO2014165662A2
Application number: PCT/US2014/032803
Authority: WO
Inventors: Noah Zachary ROTHBERG
Original assignee: Butterfly Network, Inc.
Priority date: 2013-04-03
Filing date: 2014-04-03
Publication date: 2014-10-09
Also published as: US20140300720A1; JP2016515903A; JP2019030736A; JP6786384B2; CA2908631A1; EP2981215A2; WO2014165662A3; CN105263419A; KR20150145236A; CA2908631C; US20170228862A1; US20170309023A1; US9667889B2

Abstract

A portable electronic device (e.g., smart phone or tablet computer) is provided for generating and displaying images (e.g., 2-dimensional or 3-dimensional images) of an imaging target such as a human body. The portable electronic device may include imaging elements configured to receive radiation signals transmitted through and/or reflected by the imaging target, an imaging interface, and one or more processors. The portable electronic device may display what appears to be a window into the imaging target (e.g., a human body), and/or an exploded view (e.g., 3-dimensional, upwardly projected image) of the target. The generated image may be a real-time continuous image of the internal features of the target (e.g., a human body) that is updated to track movements of the target (e.g., breathing patterns) and the relative position of the portable electronic device as the portable electronic device moves relative to a surface of the target.

Description

PORTABLE ELECTRONIC DEVICES

WITH INTEGRATED IMAGING CAPABILITIES

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application No. 13/856,252, filed on April 3, 2013, and entitled "Portable Electronic Devices with Integrated Imaging Capabilities," and incorporates its disclosure herein by reference in its entirety.

FIELD OF THE TECHNOLOGY

[0002] The present disclosure relates generally to imaging devices and methods (e.g., ultrasound imaging devices and methods).

BACKGROUND

[0003] Imaging technologies are used at various stages of medical care. For example, imaging technologies are used to non-invasively diagnose patients, to monitor the performance of medical (e.g., surgical) procedures, and/or to monitor post-treatment progress or recovery.

[0004] Conventional imaging devices and methods, including magnetic resonance imaging (MRI) technology, are typically configured for and limited to use within a fixed location in a hospital setting. MRI technology is also generally slow, and suffers from other drawbacks including high cost, loud noise, and the use of potentially harmful magnetic fields.

[0005] In view of the foregoing, it would be desirable to provide portable electronic devices and associated methods with integrated imaging capabilities.

SUMMARY

[0006] Some embodiments of the present disclosure relate to a portable electronic device (e.g., smart phone and/or tablet computer) for generating and displaying an image (e.g., 2- dimensional or 3-dimensional image) of what appears to be a window into an underlying object, such as a human body, when placed in proximity to (e.g., on or close to) the object. The window and corresponding image displayed on a display screen of the portable electronic device change as the portable electronic device is moved over various portions of the body (e.g., abdomen, thorax, etc.). The image displayed by the portable electronic device may identify, for example, organs, arteries, veins, tissues, bone, and/or other bodily contents or parts. In various embodiments, the image may be presented in 3 dimensions such at it appears to the viewer as if the viewer is looking into the body, or as if the body parts have been projected up (e.g., exploded view) from the body.

[0007] The present disclosure provides numerous embodiments of systems, apparatus, computer readable media, and methods for providing imaging functionality using a portable electronic device, such as, for example, a smart phone or a tablet computer. In some embodiments, the portable electronic device is configured to generate and display an image of what appears to be an exploded view (e.g., 3 -dimensional, upwardly projected image) of an object or its constituent parts. In some embodiments, movement of the portable electronic device results in the rendering of a different internal image of the target (e.g., different portion(s) of a human body). In some embodiments, the generated window of the underlying object (e.g., the portion of the human body) may provide an internal view of the object (e.g., a three-dimensional rendering of an organ or a portion of an organ).

[0008] In some embodiments according to one aspect of the present disclosure, a portable electronic device is provided that includes a processor configured to generate an image (e.g., ultrasound image) of an internal feature of a target when the device is positioned at an external surface of the target, and a display configured to display the image.

[0009] In some embodiments according to another aspect of the present disclosure, a portable ultrasound device is provided that includes multiple ultrasound elements configured to receive ultrasound radiation reflected by or passing through a target when the ultrasound device is pointed at the target. The portable ultrasound device also includes a display configured to display an image of an internal feature of the target based at least in part on the ultrasound radiation received by the plurality of ultrasound elements.

[0010] In some embodiments according to another aspect of the present disclosure, a method is provided that includes pointing a portable electronic device at an external surface of a subject, and viewing, on a display of the portable electronic device, an image of an internal feature of the subject while pointing the portable electronic device at the external surface of the subject. In some embodiments, the portable electronic device includes a radiation sensor, and the method further includes receiving, with the radiation sensor, radiation reflected by or passing through the subject, and creating the image of the internal feature based at least in part on the radiation received by the radiation sensor.

[0011] In some embodiments according to yet another aspect of the present disclosure, a portable electronic device is provided that renders within a window on a display of the device an image (e.g., 3-dimensional image) of an inside of a human body when the device is directed at the body (e.g., within about one meter or less of the body). In some embodiments, the image changes to reflect additional body parts as the device is moved relative to the body.

[0012] In some embodiments, the portable electronic device renders the image by processing radiation signals received by a radiation sensor which are reflected by or passing through the human body. In some embodiments, the portable electronic device is positioned within approximately one meter from the body (e.g., within 0.75 to 1.25 meters from the body).

[0013] In some embodiments according to another aspect of the present disclosure, a portable electronic device is provided that includes multiple imaging elements configured to receive radiation signals transmitted through or reflected by an imaging target and an imaging interface. The portable electronic device also includes one or more processors configured to receive one or more sensing signals from at least one of the plurality of imaging elements, and to render an image of the imaging target for display through the imaging interface based at least in part on the one or more sensing signals.

[0014] In some embodiments, each of the imaging elements is separately processed by a corresponding imaging processor, such that combining the processed signals of the imaging elements is utilized to render images having higher resolution and/or higher frame rate than images rendered based on a single imaging element. In some embodiments, the combined processed signals are used to generate a three-dimensional image of the target.

[0015] In some embodiments, the portable electronic device is a handheld portable electronic device, such as a cellular phone or a tablet computer.

[0016] In some embodiments, imaging elements may include their own dedicated processing circuitry, such as a graphic processing unit (GPU), digital signal processor (DSP), and/or central processing unit (CPU), and/or may utilize processing circuitry of the portable electronic device. For example, in some embodiments, the CPU and/or GPU of the portable electronic device 100 may be utilized for image acquisition/reconstruction and image rendering. In some embodiments, the CPU of portable electronic device may be utilized to process computations based on received signals (e.g., back-scattered signals and/or transmissive signals) in order to generate an image or topography, while the GPU may be utilized to render an image based on the information received from the CPU to generate a real-time or substantially real-time image display. In some embodiments, portable electronic device may include one or more components for processing, filtering, amplification, and/or rendering images.

[0017] In some embodiments, the processing circuitry may be fabricated on the same semiconductor chip as the ultrasound elements.

[0018] In some embodiments, the portable electronic device may include one or more processors for identifying structure(s) identified in the image based at least in part on stored data (e.g., data stored in random access memory or other storage device of portable electronic device). For example, data stored within device may identify characteristic(s) of structure(s) (e.g., one or more shapes, colors, textures, cellular characteristics, tissue characteristics, and/or other distinctive and/or surrounding features or structures) that may be present within different areas of the human body for use by personal electronic device to identify and/or predict the type(s) of structures depicted in an image rendered by device. In some embodiments, data stored within device may identify characteristics of particular disease(s) such as cancer or other abnormalities (e.g., based on image data corresponding to previously stored characteristics of particular structures associated with a disease) for use by personal electronic device to identify and/or predict the type(s) of structures depicted in an image rendered by device.

BRIEF DESCRIPTION OF DRAWINGS

[0019] Aspects and embodiments of the present disclosure will be described with reference to the following figures. It should be appreciated that the figures are not necessarily drawn to scale. Items appearing in multiple figures are indicated by the same reference number in all the figures in which they appear. [0020] FIG. 1A illustrates a portable electronic device including an imaging interface for generating and/or rendering an internal image of a human body or a portion of a human body according to some embodiments of the present disclosure.

[0021] FIG. IB illustrates a three-dimensional internal image of a portion of a human body that is generated and/or rendered by a portable electronic device according to some embodiments of the present disclosure.

[0022] FIG. 2A illustrates a front view of portable electronic device including an imaging interface according to some embodiments of the present disclosure.

[0023] FIG. 2B illustrates a back view of portable electronic device including imaging elements according to some embodiments of the present disclosure.

[0024] FIG. 3 illustrates a transmissive imaging system and method according to some embodiments of the present disclosure.

[0025] FIG. 4 illustrates a reflective imaging system and method according to some embodiments of the present disclosure.

[0026] FIG. 5 illustrates a transmissive and/or reflective imaging system and method according to some embodiments of the present disclosure.

[0027] FIG. 6A illustrates a portable electronic device including an imaging interface for generating and/or rendering an internal image of a portion of a human body at a first position and at a second position according to some embodiments of the present disclosure.

[0028] FIG. 6B illustrates a three-dimensional internal image of a portion of a human body at the first position shown in FIG. 6A that is generated and/or rendered by a portable electronic device according to some embodiments of the present disclosure.

[0029] FIG. 6C illustrates a three-dimensional internal image of a portion of a human body at the second position shown in FIG. 6A that is generated and/or rendered by a portable electronic device according to some embodiments of the present disclosure.

[0030] FIG. 7A illustrates a front view of a portable electronic device according to some embodiments of the present disclosure.

[0031] FIG. 7B illustrates a back view of a portable electronic device according to some embodiments of the present disclosure. [0032] FIG. 7C illustrates a front view of a case for a portable electronic device according to some embodiments of the present disclosure.

[0033] FIG. 7D illustrates a back view of a case including imaging elements for a portable electronic device according to some embodiments of the present disclosure.

[0034] FIG. 8A illustrates a front view of a case for a portable electronic device according to some embodiments of the present disclosure.

[0035] FIG. 8B illustrates a back view of a case including a retaining mechanism for a modular unit utilized with a portable electronic device according to some embodiments of the present disclosure.

[0036] FIG. 8C illustrates a front view of a case for a portable electronic device according to some embodiments of the present disclosure.

[0037] FIG. 8D illustrates a back view of a case including a retaining mechanism for a modular unit utilized with a portable electronic device according to some embodiments of the present disclosure.

[0038] FIG. 8E illustrates a modular unit including an imaging circuit according to some embodiments of the present disclosure.

[0039] FIG. 9A illustrates how, in some embodiments, a single transducer element may fit within a larger transducer array.

[0040] FIGs. 9B-F show five different examples of how a given transducer element within an array might be configured in some embodiments.

[0041] FIG. 10A shows an illustrative example of a monolithic ultrasound device according to some embodiments.

[0042] FIG. 10B is a block diagram illustrating how, in some embodiments, the TX control circuit and the RX control circuit for a given transducer element may be used either to energize the element to emit an ultrasonic pulse, or to receive and process a signal from the element representing an ultrasonic pulse sensed by it.

[0043] FIG. 11 illustrates an example technique for biasing transducer elements in an array or other arrangement. [0044] FIGs. 12 and 13 show illustrative examples of components that may be included within the analog processing block and the digital processing block of the RX control circuit shown in Fig. 10.

[0045] FIGs. 14A-14K illustrate a process sequence for fabricating a CMOS ultrasonic transducer (CUT) having a membrane formed above a cavity in a CMOS wafer, according to a non-limiting embodiment of the present application.

DETAILED DESCRIPTION

[0046] According to some embodiments of the present disclosure, a portable electronic device is provided that includes an imaging interface and one or more imaging elements. For example, the portable electronic device may be a cellular phone, personal digital assistant, smart phone, tablet device, digital camera, laptop computer, or the like. An image may be generated and/or rendered utilizing the portable electronic device. For example, the portable electronic device may be utilized to simulate a "window" into an imaging target, such as a human body or portion of the body. The simulated "window" may provide a view of the inside of a human body or portion of the body, including organs, arteries, veins, tissues, bone, and/or other bodily contents or parts. For example, an image (e.g., ultrasound or sonographic image) may be generated that illustrates and/or simulates internal features of the imaging target for a user. In some embodiments, a real-time continuous or substantially real-time continuous image (e.g., 10 frames/second, 20 frames/second, 25 frames/second, 30 frames/second, or the like) may be generated and/or rendered such that movement of the portable electronic device results in a substantially real-time updated image of the area that corresponds to the new position of the portable electronic device. In some embodiments, internal movement of the target object (e.g., such as expansion and/or contraction of organs) may be rendered in real-time by the portable electronic device.

[0047] In some embodiments, the portable electronic devices and methods described herein may include, be coupled to (e.g., via a suitable communications connection or port such as a USB link), or otherwise utilize one or more radiation sources, sensors, and/or transducers (e.g., array(s) of ultrasound transducers), front-end processing circuitry and associated processing techniques, and/or image reconstruction devices and/or methods, in order to generate and/or render images to a user according to the non-limiting embodiments described in detail throughout the present disclosure.

[0048] In some embodiments of the present disclosure, one or more of the devices described in Figures 1A-8E herein may include or be coupled to one or more ultrasound imaging elements (e.g., one or more arrays of ultrasound sources, sensors, and/or transducers). One or more computers or processors within the portable electronic device may perform image analysis and/or image rendering based at least in part on radiation signals received by an imaging device.

[0049] FIG. 1 A illustrates a portable electronic device 100 including an imaging interface 102 for generating and/or rendering an internal image of a human body or a portion of a human body 106 according to some embodiments. FIG. IB illustrates a three-dimensional internal image 110 of a portion of a human body that is generated and/or rendered by a portable electronic device 100 according to some embodiments. As shown in FIG. 1A, the portable electronic device 100 may be positioned in an area near (e.g. in contact with the surface of or within about one meter from the surface of) a portion of a human body that is to be imaged and/or analyzed. The portable electronic device 100 may include imaging elements 104 that are configured to transmit and/or receive radiation signals. The imaging elements 104, along with other components and functions of the portable electronic device 100 according to some embodiments of the present disclosure will be described in greater detail below with reference to FIG. 2A-2B. An internal image 110 as shown in FIG. IB may be generated by the portable electronic device 100. The internal image 1 10 may be a three- dimensional internal image of a portion of the human body that appears to a viewer 117 to project upward from a surface of the portable electronic device 100, giving the viewer the perception of a viewing window into the underlying body. Through generation of the internal image, the portable electronic device 100 may provide a window into the internal areas of the human body that are below the surface. As will be described in greater detail below with reference to FIGs. 6A-6C, the generated images may be real-time continuous images such that the images are dynamically updated based on movement of the portable electronic device 100 and/or the image target (e.g., internal organs of the human body). [0050] FIG. 2A illustrates a front view of portable electronic device 100 including an imaging interface 102 according to some embodiments of the present disclosure. The imaging interface 102 of the portable electronic device 100 may include a display that is configured to output a two-dimensional (2-D) or three-dimensional (3-D) image of an imaging target. In some embodiments, the imaging interface 102 is interactive and is capable of receiving user input, for example through a touch-screen. An image that is displayed via the imaging interface 102 may be adjusted based on the received inputs, for example, to adjust zoom level, centering position, level of detail, depth of an underlying object to be imaged, resolution, brightness, color and/or the like of the image. For example, in some embodiments, imaging interface 102 may be configured to allow a user to selectively traverse various layers and imaging depths of the underlying object using, for example, the touch screen.

[0051] Portable electronic device 100 may render a three-dimensional image of the imaging target using any suitable method or combination of methods (e.g., anaglyph, polarization, eclipse, interference filtering, and/or austosteroscopy). For example, in some embodiments, the imaging interface 102 includes a circular polarizer and/or a linear polarizer such that a viewer having polarizing filtering spectacles can view a three-dimensional image. In some embodiments, the imaging interface 102 is configured to display alternating left and right images such that a viewer having spectacles with shutters that alternate in conjunction with the displayed image views the image as a three-dimensional image. In some embodiments, the imaging interface 102 may utilize an autostereoscopy method such that 3- D spectacles are not necessary for use by a viewer to view the three-dimensional image.

[0052] In some embodiments, portable electronic device 100 may display information (e.g., text and/or graphics) in addition to (e.g., graphically overlaid on top of or adjacent to) an image of a targeted object, such as, for example, text and/or graphics identifying the structure(s) identified in the image (e.g., organs, arteries, veins, tissues, bone, and/or other bodily contents or parts). In some embodiments, portable electronic device 100 may include one or more processors for identifying structure(s) identified in the image based at least in part on stored data (e.g., data stored in random access memory or other storage device of portable electronic device 100). For example, data stored within device 100 may identify characteristic(s) of structure(s) (e.g., one or more shapes, colors, textures, cellular characteristics, tissue characteristics, and/or other distinctive and/or surrounding features or structures) that may be present within different areas of the human body for use by personal electronic device 100 to identify and/or predict the type(s) of structures depicted in an image rendered by device 100. In some embodiments, data stored within device 100 may identify characteristics of particular disease(s) such as cancer or other abnormalities for use by personal electronic device 100 to identify and/or predict the type(s) of structures depicted in an image rendered by device 100. In some embodiments, the image, text, graphics, and/or other information displayed on the user interface 104 may be adjusted through user interaction with one or more inputs (e.g., touch screen, buttons, touch-sensitive areas, or the like) of the portable electronic device 100.

[0053] FIG. 2B illustrates a back view of portable electronic device 100 including imaging elements 104 according to some embodiments of the present disclosure. The imaging elements 104 may be configured as sources (emitters) and/or sensors of ultrasound radiation and/or other radiation. In some embodiments, the imaging elements 104 may be of substantially the same size and/or may be arranged in an array as shown in FIG. 2B. In some embodiments, the imaging elements 104 may be of different sizes and/or arranged in an irregular or scattered configuration. In some embodiments, one or more (e.g., all) of the imaging elements 104 may be arranged in the same plane. In other embodiments, at least some of imaging elements may be arranged in at least two different planes. In some embodiments, all of the imaging elements 104 included in the portable electronic device 100 may be either emitting elements or sensing elements. In some embodiments, the imaging elements 104 may include both emitting elements and sensing elements. The embodiment shown in FIG. 2B includes a 4x6 array of imaging elements 104, by way of illustration only and is not intended to be limiting. In other embodiments, any other suitable numbers of imaging elements may be provided (e.g., 10, 20, 30, 40, 50, 100, 200, 500, 1000, or any number in between, or more) and may be arranged in any suitable configuration.

[0054] In some embodiments, the imaging elements 104 may be integrated within a circuit board (e.g., a printed circuit board) that includes, for example, processing (e.g., image processing) components of the portable electronic device 100. In some embodiments, the imaging elements 104 may be provided on a separate circuit board or layer of a circuit board than the processing components of the portable electronic device 100, and may be in communication with the processing circuitry through a suitable communications link (e.g., an internal bus, USB link, or other port). In some embodiments, as will be described in connection with FIGs. 14A-14K below, the imaging elements 104 may be micro fabricated on a semiconductor chip having the processing circuitry.

[0055] The imaging elements 104 according to some embodiments of the present disclosure may include their own dedicated processing circuitry, such as a graphic processing unit (GPU), digital signal processor (DSP), and/or central processing unit (CPU), and/or may utilize processing circuitry of the portable electronic device 100. For example, in some embodiments, the CPU and/or GPU of the portable electronic device 100 may be utilized for image acquisition/reconstruction and image rendering. In some embodiments, the CPU of portable electronic device 100 may be utilized to process computations based on received signals (e.g., back-scattered signals and/or transmissive signals) in order to generate an image or topography, while the GPU may be utilized to render an image based on the information received from the CPU to generate a real-time or substantially real-time image display. In some embodiments, portable electronic device 100 may include one or more components for processing, filtering, amplification, and/or rendering images.

[0056] FIG. 3 illustrates a transmissive imaging system and method 301 according to some embodiments of the present disclosure. As shown in FIG. 3, the transmissive imaging system 301 includes two portable electronic devices 100 A and 100B that are on opposing or generally opposing sides of an imaging target 306. In other embodiments, devices 100A and 100B may be positioned in any other relationship with respect to one another. In some embodiments, devices 100A and/or 100B may include one or more sensors for determining the relative positions of these devices to aid in the generation of image(s). While shown as a portable electronic device 100B (e.g., smart phone), in some embodiments device 100B may be a dedicated sensing and/or emitting device such as an array of ultrasound elements and associated circuitry. Signals (e.g., waves or beams 308) emitted from the portable electronic device 100B are sensed by the portable electronic device 100A and are utilized to render a 2- D or 3-D image 310 (e.g., real-time or substantially real-time image) of the target 306. In some embodiments, a generated 3-D image may be in the form of a pop-out image or a depth image. In some embodiments, the portable electronic device 100A may be configured to transmit signals (e.g., waves or beams) 308 though the target 306 to be received by the portable electronic device 100B. In some embodiments, the portable electronic device 100B may simultaneously or substantially simultaneously render an image (e.g., back view or alternate view or level of detail of an image rendered by device 100A) based at least in part on processing sensed signals. In some embodiments, the portable electronic devices 100A and/or 100B may communicate the results of the sensed signals to the other in order to generate or improve a rendered image, for example, by providing higher resolution and/or a greater frame rate. For example, a rendering device may send feedback to a signal emission device regarding the rendered image, and in response, the signal emitting device may adjust a power level, signal type, signal frequency, or other signaling parameter in order to improve the image rendered by the rendering device.

[0057] FIG. 4 illustrates a back-scatter or reflective imaging system and method 401 according to some embodiments of the present disclosure. As shown in FIG. 4, a portable electronic device 100 may utilize emission and/or sensing elements 104 in order to render an image 410 based at least in part on reflection (e.g., back-scatter effect) of the signals 408. In some embodiments, portable electronic device 100 is the only device utilized in order to image the target (e.g., to produce an image appearing as a window into a human body). For example, the portable electronic device 100 may include both radiation sources and sensors (e.g., separate sources and sensors, and/or multiple transducers functioning as both sources and sensors), where all or substantially all of the radiation utilized by the sensors to reconstruct image(s) is backscatter radiation or radiation produced through a similar effect.

[0058] FIG. 5 illustrates a transmissive and/or reflective imaging system and method 501 according to some embodiments of the present disclosure. As shown in FIG. 5, a plurality of devices, such as portable electronic devices 500A, 500B, 500C, and/or 500D may be utilized in order to render one or more image(s) 510 of target 506 on portable electronic device 500B. Each of the portable electronic devices 500A-500D may be configured to emit signals (e.g., waves or beams) 508 as shown in FIG. 5. The image 510, or alternate views of the image or imaged structure, may be rendered on the other portable electronic devices (e.g., 500A, 500C, and 500D) through communication with one-another. In some embodiments, each of the devices (e.g., 500A, 500C, and/or 500D) may be configured as emitting and/or sensing devices only. The image 510 that is rendered on portable device 500B may be based at least in part on signals 508 that are emitted by one or more of the devices 500A-500D, and which are sensed through reflection (e.g., back-scatter) and/or transmission by one or more of the devices 500A-500D.

[0059] In some embodiments, one or more portable electronic devices according to the present disclosure may generate and/or render an image based solely on signals received by one or more sensors (e.g., ultrasound transducers) of the device. In some embodiments, one or more portable electronic devices according to the present disclosure may generate and/or render an image based at least in part on information stored in memory (e.g., random access memory) of the portable device(s) identifying detail(s) regarding the structure(s), part(s), composition(s), and/or other characteristic(s) of object(s) to be imaged. For example, in some embodiments, when data received by one or more sensor(s) of the portable electronic devices indicates that the object being imaged is a particular body part or region, the portable electronic devices may use stored data in addition to the received data in order to generate an image of the object and/or its constituent part(s), and/or to provide additional detail or explanation regarding an object and/or its constituent parts. For example, stored data may be compared to the received data in order to determine differences between a previously rendered image or frame and a current image or frame such that an updated image can be generated by changing the output of pixels corresponding to the determined differences.

[0060] In some embodiments of the present disclosure, the generated and/or rendered image may be a real-time or substantially real-time image that is dynamically updated based on movement of a portable electronic device 100 along a surface of an imaging target and/or motion of the imaging target. FIG. 6A illustrates a portable electronic device 100 including an imaging interface 102 for generating and/or rendering an internal image of a portion of a human body at a first position and at a second position according to some embodiments. FIG. 6B illustrates a three-dimensional internal image 610 of a portion of a human body at the first position shown in FIG. 6A that is generated and/or rendered by a portable electronic device 100 according to some embodiments. FIG. 6C illustrates a three-dimensional internal image 610 of a portion of a human body at the second position shown in FIG. 6A that is generated and/or rendered by a portable electronic device 100 according to some embodiments. As shown in FIG. 6B, a three-dimensional internal image 610 of a portion of the human body may be generated and displayed to a viewer 617. The three-dimensional image 610 may appear to the viewer 617 as an image having variations in, for example, topography that correspond to the surfaces and/or other aspects or features of the internal portion of the body at the first position of the portable electronic device 100 as shown in FIG. 6A. The three-dimensional image 610 may be a real-time continuous image (e.g., video image) that is dynamically updated based on movement of the portable electronic device 100 and/or the internal portion of the body that is being analyzed. As shown in FIG. 6C, a different three-dimensional internal image 610 is displayed to the viewer 617 showing different underlying structures and/or aspects (e.g., organs, arteries, veins, tissues, bone, and/or other bodily contents or parts). The three-dimensional internal image 610 shown in FIG. 6C corresponds to the internal image of the body portion corresponding to the second position of the portable electronic device 100 as shown in FIG. 6A. As shown in FIG. 6C, the internal image 610 is illustrated as a different image showing different topographical and/or other aspects or features of the body portion than the internal image 610 shown in FIG. 6B. As discussed above, through selection of different aspect ratios and/or zoom settings, as well as through positioning of the portable electronic device 600, different types of internal images of a target may be generated, such as a three-dimensional view of an entire organ or multiple organs.

[0061] In some embodiments, the imaging elements, including sensors and/or sources (e.g., transducers), may be provided on, in, or otherwise coupled to a case for a portable electronic device. FIG. 7A illustrates a front view of a portable electronic device 700 according to some embodiments of the present disclosure. The portable electronic device 700 includes an imaging interface 702. FIG. 7B illustrates a back view of the portable electronic device 700 according to some embodiments of the present disclosure. As shown in FIGs. 7A and 7B, unlike the portable electronic device 100, the portable electronic device 700 does not include imaging elements 104 as part of the main housing or enclosure of device 700. [0062] FIG. 7C illustrates a front view of a case 711 for a portable electronic device according to some embodiments of the present disclosure. FIG. 7D illustrates a back view of the case 711 including imaging elements for a portable electronic device according to some embodiments of the present disclosure. The case 711 may be configured to be attached to the portable electronic device so as to at least partially enclose the portable electronic device 700. In some embodiments, case 711 may simultaneously provide imaging capabilities to portable electronic device 700 and serve as a protective case. The case may be made of any suitable material such as rubber, plastic, leather, and/or the like. As shown in FIG. 7D, an imaging circuit 712 (e.g., an integrated circuit) may be provided on (e.g., directly on), embedded in, and/or otherwise coupled to the back surface and/or other surface(s) of the case 711. Case 711 may be considered part of portable electronic device 700.

[0063] The imaging circuit 712 may include one or more imaging elements 104. As discussed above, the imaging elements 104 may include sources and/or sensors. The imaging circuit 712 may also include a communication device 714 configured to communicate with the portable electronic device 700 via a wired or wireless link. For example, the imaging circuit 712 may include a communication transmitter/receiver which utilizes an infrared signal, a Bluetooth communication signal, a near-field communication signal, and/or the like to communicate with the portable electronic device 700. In some embodiments, the communication device 714 may be in communication with the processing circuitry of a portable electronic device through a wired communications link (e.g., a USB port, or other data port), or combination of wired and wireless links. In some embodiments, the imaging circuit 712 may receive power through wired and/or wireless connection(s) to the portable electronic device. In some embodiments, the imaging circuit 712 may receive power from a separate power source (e.g., a battery) that is coupled to the imaging circuit 712. In some embodiments, when the portable electronic device 700 is coupled to or attached to the case 711, a software application and/or drivers are automatically loaded and/or executed by the portable electronic device 700 in order to render an image based on communication with the imaging circuit 712. The software application and/or drivers may be stored in a memory of the imaging circuit 712 and communicated to the portable electronic device 700 and/or may be retrieved by the portable electronic device through a network (e.g., the internet). [0064] In some embodiments, the portable electronic device 700 receives raw data from the communication device 714 and processes the raw data using processing circuitry (e.g., image signal processor, digital signal processor, filters, and/or the like) included in the portable electronic device 700. In some embodiments, the imaging circuit 712 includes a local imaging processor 716 configured to process signals received by imaging elements 104. The communication device 714 may be configured to communicate data received from the imaging elements 104 (e.g., such as raw sensor data) and/or may communicate processed data that is received from the local imaging processor 716. As shown in FIG. 7A, the portable electronic device 700 includes an interface 702 for displaying an image that is rendered by processing signals received from the communication device 714.

[0065] In some embodiments, an imaging circuit (e.g., an integrated circuit) may be provided separately such that it can be mounted and/or attached to different cases used by different portable electronic devices. FIG. 8A illustrates a front view of a case 811 A for a portable electronic device according to some embodiments of the present disclosure. FIG. 8B illustrates a back view of the case 811 A including a retaining mechanism 820 for a modular unit 830 utilized with a portable electronic device according to some embodiments of the present disclosure. FIG. 8C illustrates a front view of a case 81 IB for a portable electronic device according to some embodiments of the present disclosure. FIG. 8D illustrates a back view of the case 81 IB including a retaining mechanism for a modular unit 830 utilized with a portable electronic device according to some embodiments of the present disclosure. FIG. 8E illustrates a modular unit 830 including an imaging circuit 712 according to some embodiments of the present disclosure. As shown in FIGs. 8A-8D, the case 811 A has a different shape than the case 81 IB. The case 811 A may be utilized for a first portable electronic device, while the case 81 IB may be utilized for a second portable electronic device having a different size and/or shape than the first portable electronic device. Each of the cases 811 A and 81 IB includes a retaining mechanism 820 that is configured to retain the modular unit 830.

[0066] The modular unit 830 may include the imaging circuit 712 as discussed above with reference to FIGs. 7A-7D. The imaging circuit 712 may include one or more imaging elements 104, a communication device 714, and/or a local imaging processor 716. The modular unit 830 also includes a coupling mechanism 832 that is configured to engage with the retaining mechanism 820 of the cases 811 A and 81 IB. For example, in some embodiments, the retaining mechanism 820 may correspond to a slot on the case 811 A and/or 81 IB that is configured to receive the modular unit 830. The coupling mechanism 832 may be shaped to correspond to the slot of the case 811 A and/or 81 IB such that the modular unit 830 may be secured by the case 811 A and/or 81 IB. In some embodiments, the retaining mechanism 820 and the coupling mechanism 832 may include corresponding structures for locking the modular unit 830 in place during use. In some embodiments, the retaining mechanism 820 may include one or more magnets having a first polarity, and the coupling mechanism 832 may include one or more magnets having a second polarity that is opposite of the first polarity such that the modular unit 830 can be retained by the case 81 1 A and/or 811B.

[0067] As described with reference to FIGs. 8A-8E, since the modular unit 830 may be incorporated with different cases 811 A and/or 81 IB that are utilized for different portable electronic devices, the modular unit 830 may advantageously provide flexibility in the incorporation of an imaging system with different portable electronic devices. Furthermore, different cases 811 A and 81 IB may be manufactured using any suitable techniques (e.g., 3-D printing, injection molding, or the like). In some embodiments, case 811 A and/or case 81 IB may be manufactured at low cost such that the different cases 811 A and 81 IB may be discarded and/or upgraded while remaining compatible with the modular unit 830. As a result, the modular unit 830 can be integrated into and utilized by a user with a plurality of portable electronic devices even when the design of the portable electronic devices is changed (e.g., updated and/or upgraded).

[0068] Examples of suitable imaging devices that may integrated within or coupled to a portable electronic device according to some embodiments of the present disclosure are described in connection with FIGs. 9A-9F, 13, and 14A-14K below, and in commonly-owned U.S. Patent Application Serial No. 13/654,337 filed October 17, 2012, and entitled "Transmissive Imaging and Related Apparatus and Methods;" U.S. Provisional Application Serial No. 61/798,851 filed March 15, 2013, and entitled "Monolithic Ultrasonic Imaging Devices, Systems and Methods;" and U.S. Provisional Application Serial No. 61/794,744 filed on March 15, 2013, and entitled "Complementary Metal Oxide Semiconductor (CMOS) Ultrasonic Transducers and Methods for Forming the Same," each of which is incorporated by reference in its entirety.

[0069] FIG. 9 A illustrates how, in some embodiments, a single transducer element 104 may fit within a larger transducer array 900. Figs. 9B-F show five different examples of how a given transducer element 104 comprised of circular transducer cells 900 within an array 900 might be configured in some embodiments. As shown in Fig. 9B, in some embodiments, each transducer element 104 in an array 900 may include only a single transducer cell 902 (e.g., a single CUT or CMUT). As shown in Figs. 9B-F, in other embodiments, each transducer element 104 in an array 900 may include a group of individual transducer cells 902 (e.g., CUTs or CMUTs). Other possible configurations of transducer elements 104 include trapezoidal elements, triangular elements, hexagonal elements, octagonal elements, etc. Similarly, each transducer cell 902 (e.g., CUT or CMUT) making up a given transducer element 104 may itself take on any of the aforementioned geometric shapes, such that a given transducer element 104 may, for example, include one or more square transducer cells 902, rectangular transducer cells 902, circular transducer cells 902, asterisk-shaped transducer cells 902, trapezoidal transducer cells 902, triangular transducer cells 902, hexagonal transducer cells 902, and/or octagonal transducer cells 902, etc.

[0070] In some embodiments, at least two of (e.g., all) of the transducer cells 902 within each given transducer element 104 act as a unit and together generate outgoing ultrasonic pulses in response to the output of the same pulser (described below) and/or together receive incident ultrasonic pulses and drive the same analog reception circuitry. When multiple transducer cells 902 are included in each transducer element 104, the individual transducer cells 902 may be arranged in any of numerous patterns, with the particular pattern being chosen so as to optimize the various performance parameters, e.g., directivity, signal-to-noise ratio (SNR), field of view, etc., for a given application. In some embodiments in which CUTs are used as transducer cells 902, an individual transducer cell 902 may, for example, be on the order of about 20-1 ΙΟμιη wide, and have a membrane thickness of about 0.5-1.0μιη, and an individual transducer element 104 may have a depth on the order of about 0.1-2.0 μιη, and have a diameter of about 0.1mm-3mm, or any values in between. These are only illustrative examples of possible dimensions, however, and greater and lesser dimensions are possible and contemplated.

[0071] Fig. 10A shows an illustrative example of a monolithic ultrasound device 1000 according to some embodiments. As shown, the device 1000 may include one or more transducer arrangements (e.g., arrays) 900, a transmit (TX) control circuit 1004, a receive (RX) control circuit 1006, a timing & control circuit 1008, a signal conditioning/processing circuit 1010, a power management circuit 1018, and/or a high-intensity focused ultrasound (HIFU) controller 1020. In the embodiment shown, all of the illustrated elements are formed on a single semiconductor die 1012. It should be appreciated, however, that in alternative embodiments one or more of the illustrated elements may be instead located off-chip. In addition, although the illustrated example shows both a TX control circuit 1004 and an RX control circuit 1006, in alternative embodiments only a TX control circuit or only an RX control circuit may be employed. For example, such embodiments may be employed in a circumstance where one or more transmission-only devices 1000 are used to transmit acoustic signals and one or more reception-only devices 1000 are used of receive acoustic signals that have been transmitted through or reflected by a subject being ultrasonically imaged.

[0072] Fig. 10B is a block diagram illustrating how, in some embodiments, the TX control circuit 1004 and the RX control circuit 1006 for a given transducer element 104 may be used either to energize the transducer element 104 to emit an ultrasonic pulse, or to receive and process a signal from the transducer element 104 representing an ultrasonic pulse sensed by it. In some implementations, the TX control circuit 1004 may be used during a "transmission" phase, and the RX control circuit may be used during a "reception" phase that is non-overlapping with the transmission phase. In other implementations, one of the TX control circuit 1004 and the RX control circuit 1006 may simply not be used in a given device 1000, such as when a pair of ultrasound units 200 is used for only transmissive imaging. As noted above, in some embodiments, a device 1000 may alternatively employ only a TX control circuit 1004 or only an RX control circuit 1006, and aspects of the present technology do not necessarily require the presence of both such types of circuits. In various embodiments, each TX control circuit 1004 and/or each RX control circuit 1006 may be associated with a single transducer cell 900 (e.g., a CUT or CMUT), a group of two or more transducer cells 902 within a single transducer element 104, a single transducer element 104 comprising a group of transducer cells 902, a group of two or more transducer elements 104 within an array 900, or an entire array 900 of transducer elements 104.

[0073] In the example shown in Fig. 10B, there is a separate TX control circuit 1004/RX control circuit 1006 combination for each transducer element 104 in the array(s) 900, but there is only one instance of each of the timing & control circuit 1008 and the signal conditioning/processing circuit 1010. Accordingly, in such an implementation, the timing & control circuit 1008 may be responsible for synchronizing and coordinating the operation of all of the TX control circuit 1004/RX control circuit 1006 combinations on the die 1012, and the signal conditioning/processing circuit 1010 may be responsible for handling inputs from all of the RX control circuits 1006 (see element 1005 in Fig. 10) on the die 1012.

[0074] As shown in Fig. 10B, in addition to generating and/or distributing clock signals to drive the various digital components in the device 1000, the timing and control circuit 1008 may output either a "TX enable" signal to enable the operation of each TX control circuit 1004, or an "RX enable" signal to enable operation of each RX control circuit 1006. In the example shown, a switch 1003 in the RX control circuit 1006 may always be opened before the TX control circuit 1004 is enabled, so as to prevent an output of the TX control circuit 1004 from driving the RX control circuit 1006. The switch 1003 may be closed when operation of the RX control circuit 1006 is enabled, so as to allow the RX control circuit 1006 to receive and process a signal generated by the transducer element 104.

[0075] As shown, the TX control circuit 1004 for a respective transducer element 104 may include both a waveform generator 1007 and a pulser 1009. The waveform generator 1007 may, for example, be responsible for generating a waveform that is to be applied to the pulser 1009, so as to cause the pulser 1009 to output a driving signal to the transducer element 104 corresponding to the generated waveform.

[0076] In the example shown in Fig. 10B, the RX control circuit 1006 for a respective transducer element 104 includes an analog processing block 1011, an analog-to-digital converter (ADC) 1013, and a digital processing block 1015. The ADC 1013 may, for example, comprise a 10-bit, 20Msps, 40Msps, or 80Msps ADC. [0077] After undergoing processing in the digital processing block 1015, the outputs of all of the RX control circuits 1006 on the die 1012 (the number of which, in this example, is equal to the number of transducer elements 104 on the chip) are fed to a multiplexer (MUX) 1017 in the signal conditioning/processing circuit 1010. The MUX 1017 multiplexes the digital data from the various RX control circuits 1006, and the output of the MUX 1017 is fed to a multiplexed digital processing block 1019 in the signal conditioning/processing circuit 1010, for final processing before the data is output from the die 1012, e.g., via one or more high-speed serial output ports 1014. Examples of implementations of the various circuit blocks shown in Fig. 10B are discussed further below. As explained in more detail below, various components in the analog processing block 1011 and/or the digital processing block 1015 may serve to decouple waveforms from the received signal and otherwise reduce the amount of data that needs to be output from the die 1012 via a high-speed serial data link or otherwise. In some embodiments, for example, one or more components in the analog processing block 1011 and/or the digital processing block 1015 may thus serve to allow the RX control circuit 1006 to receive transmitted and/or scattered ultrasound pressure waves with an improved signal-to-noise ratio (SNR) and in a manner compatible with a diversity of waveforms. The inclusion of such elements may thus further facilitate and/or enhance the disclosed "ultrasound-on-a-chip" solution in some embodiments.

[0078] Although particular components that may optionally be included in the analog processing block 1011 are described below, it should be appreciated that digital counterparts to such analog components may additionally or alternatively be employed in the digital processing block 1015. The converse is also true. That is, although particular components that may optionally be included in the digital processing block 1015 are described below, it should be appreciated that analog counterparts to such digital components may additionally or alternatively be employed in the analog processing block 1011.

[0079] Fig. 11 illustrates an example of a technique for biasing the transducer elements 104 in an array 900. As shown, the side of each of the transducer elements 104 that faces the patient may be connected to ground, so as to minimize risk of electric shock. The other side of each transducer element 104 may be connected to the output of the pulser 1009 via a resistor 1102. Accordingly, each transducer element 104 is always biased via the output of the pulser 1009, regardless of whether the switch SI is open or closed. In some embodiments, e.g., embodiments employing transducer elements 104 comprising one or more CUTs or CMUTs, the bias voltage applied across the element may be on the order of 100V.

[0080] As illustrated in the accompanying timing diagram of Fig.11 , the switch S 1 may be closed during a transmit operation and may be open during a receive operation. Conversely, the switch S2 may be closed during a receive operation and may be open during a transmit operation. (Note that there is always a gap between the opening of switch S 1 and the closing of switch S2, as well as between the opening of switch S2 and the closing of switch SI, so as to ensure the pulser 1009 does not apply an outgoing pulse to the LNA 1101 in the RX control circuit 1006.)

[0081] As also shown in the timing diagram, the pulser 1009 may hold the bottom plate of the transducer element 104 at its high output level at all times except when it is applying a waveform pulse to its transducer element 104, and the waveform pulse applied during the transmit phase may be referenced from the high output level of the pulser 1009. Accordingly, each individual pulser 1009 is able to maintain a bias on its corresponding transducer element 104 at all times. As shown in Fig.11 , a capacitor 1104 may be placed between the switch S2 and the LNA 1101 of the RX control circuit 1006 so as to block the DC bias signal (i.e., the high output of the pulser 1009) from reaching the LNA 1101 during receive operations (i.e., when switch S2 is closed).

[0082] Biasing the transducer elements 104 via their respective pulsers 1009 may provide benefits in some embodiments, such as reducing cross-talk that would otherwise occur if the elements 104 were biased via a common bus, for example.

[0083] Fig. 12 shows an example implementation of the RX control circuit 1006 that includes a matched filter 1202 that may, for example, perform waveform removal and improve the signal-to-noise ratio of the reception circuitry. As shown in Fig. 12, the analog processing block 1011 may, for example, include a low-noise amplifier (LNA) 1201, a variable-gain amplifier (VGA) 1204, and a low-pass filter (LPF) 1206. In some embodiments, the VGA 1204 may be adjusted, for example, via a time-gain compensation (TGC) circuit. The LPF 1206 provides for anti-aliasing of the acquired signal. In some embodiments, the LPF 1206 may, for example, comprise a 2^nd order low-pass filter having a frequency cutoff on the order of 5MHz. Other implementations are, however, possible and contemplated.

[0084] In the example of Fig. 12, the digital control block 1015 of the RX control circuit 1006 includes a digital quadrature demodulation (DQDM) circuit 1208 and an output buffer 1216. The DQDM circuit 1208 may, for example, be configured to mix down the digitized version of the received signal from center frequency to baseband, and then low-pass filter and decimate the baseband signal. An illustrative embodiment of a circuit suitable for use as the matched filter 1202 is shown in FIG. 13.

[0085] Although labeled a "matched" filter, the filter circuit 1202 may actually operate as either a matched filter or a mismatched filter so as to decouple waveforms from the received signal. The matched filter 1202 may work for either linear frequency modulated (LFM) or non-LFM pulses.

[0086] As shown in FIG. 13, the matched filter 1202 may, for example, include a padding circuit 1302, a fast Fourier transformation (FFT) circuit 1304, a multiplier 1306, a low-pass filter 1308, a decimator circuit 1310, and an inverse FFT circuit 1312. If employed, the padding circuit 1302 may, for example, apply padding to the incoming signal sufficient to avoid artifacts from an FFT implementation of circular convolution.

[0087] To operate as a "matched" filter, the value of Ή(ω)" applied to the multiplier 1306 should be a conjugate of the transmission waveform Τ_χ(ω). In some embodiments, the filter 2202 may thus indeed operate as a "matched" filter, by applying a conjugate of the transmission waveform Τ_χ(ω) to the multiplier 1306. In other embodiments, however, the "matched" filter 2202 may instead operate as a mismatched filter, in which case some value other than a conjugate of the transmission waveform Τ_χ(ω) may be applied to the multiplier 1306.

[0088] A process for forming an ultrasonic transducer (e.g., transducer cells 902) having a membrane above a cavity in a CMOS wafer is now described. Referring to FIG. 14A, the process may begin with a CMOS wafer 1400 including a substrate 1402, a dielectric or insulating layer 1404, a first metallization layer 1406 and a second metallization layer 1408, which in some embodiments may be a top metallization layer of the CMOS wafer 1400. [0089] The substrate 1402 may be silicon or any other suitable CMOS substrate. In some embodiments, the CMOS wafer 1400 may include CMOS integrated circuitry (IC), and thus the substrate 1402 may be a suitable substrate for supporting such circuitry.

[0090] The insulating layer 1404 may be formed of Si0₂ or any other suitable dielectric insulating material. In some embodiments, the insulating layer 1404 may be formed via tetraethyl orthosilicate (TEOS), though alternative processes may be used.

[0091] While the CMOS wafer 1400 is shown as including two metallization layers 1406 and 1408, it should be appreciated that CMOS wafers according to the various aspects of the present application are not limited to having two metallization layers, but rather may have any suitable number of metallization layers, including more than two in some embodiments. Such metallization layers may be used for wiring (e.g., as wiring layers) in some embodiments, though not all embodiments are limited in this respect.

[0092] The first and second metallization layers 1406 and 1408 may have any suitable construction. In the embodiment illustrated, at least the second metallization layer 1408 may have a multi-layer construction, including a middle conductive layer 1412 (e.g., formed of aluminum or other suitable conductive material) and upper and lower liner layers 1410 and 1414, respectively. The liner layers 1410 and 1414 may be formed of titanium nitride (TiN) or other suitable conductive material (e.g., metals other than TiN, such as tantalum, or other suitable metals for acting as a liner). In some embodiments, the upper liner layer 1410 may be used as an etch stop, for example during one or more etch steps used in as part of a process for forming a cavity for an ultrasonic transducer. Thus, the liner layer 1410 may be formed of a material suitable to act as an etch stop in some embodiments. Moreover, while not shown, the first and second metallization layers 1406 and 1408, as well as any other metallization layers described herein, may optionally include silicon oxynitride (SiON) as an upper layer (e.g., on top of liner layer 1410) to serve as an anti-reflective coating during lithography stages.

[0093] In some embodiments, it may be desirable to form an electrode from the second metallization layer 1408 serving as an electrode of an ultrasonic transducer. Also, the second metallization layer 1408 may be used to make electrical contact to a membrane of a CUT to be formed on the CMOS wafer. Accordingly, as shown in FIG. 14B, the second metallization layer 1408 may be suitably patterned to form an electrode 1416 and one or more contacts 1418.

[0094] While FIG. 14B illustrates a configuration in which an electrode and electrical contacts are formed on a CMOS wafer from a metallization layer, it should be appreciated that other manners of forming an electrode (e.g., electrode 1416) and/or electrical contacts (e.g., electrical contacts 1418) may be implemented. For example, conductive materials other than metals but suitable to act as electrodes and/or electrical contacts may be suitably processed on the CMOS wafer to form the illustrated electrode and/or electrical contacts.

[0095] An insulating layer 1420 may then be deposited as shown in FIG. 14C. The insulating layer 1420 may be Si0₂ or any other suitable insulator, and may be formed in any suitable manner. In some embodiments, the insulating layer 1420 may be formed by high density plasma (HDP) deposition. The insulating layer 1420 may then be planarized (not shown), for example using chemical mechanical polishing (CMP) or other suitable planarization technique.

[0096] In FIG. 14D, the insulating layer 1420 may be etched as shown to expose the upper surface of the electrode 1416 and electrical contacts 1418. In some embodiments, the upper liner layer 1410 may be used as an etch stop for a selective etch used to etch the insulating layer 1420. As an example, the liner layer 1410 may be formed of TiN and may be used as an etch stop, though not all embodiments are limited in this respect.

[0097] A further insulating layer 1422 may be deposited as shown in FIG. 14E to cover the upper surfaces of the electrode 1416 and electrical contacts 1418 and may then be patterned as shown in FIG. 14F to open contact holes 1424 for the electrical contacts 1418. The insulating layer 1422 may be Si0₂ or any other suitable insulator.

[0098] As shown in FIG. 14G, a conductive layer 1426 may be deposited. The conductive layer may be used to form electrical contacts to a membrane of an ultrasonic transducer, as will be shown in connection with FIG. 14 J. Also, the conductive layer 1426 may be patterned to form a cavity therein for a CUT, with a remaining portion of the conductive layer 1426 defining one or more sidewalls of the cavity. In some embodiments, then, the conductive layer 1426 may also represent a spacer in that a membrane may be separated from the surface of the CMOS wafer 1400 by the height of the conductive layer 1426. Thus, the conductive layer 1426 may serve one or more of multiple possible functions.

[0099] The conductive layer 1426 may be formed of any suitable conductive material. In some embodiments, the conductive layer 1426 may be formed of a metal. For example, the conductive layer 1426 may be TiN in some embodiments.

[0100] The conductive layer 1426 may be planarized (not shown) using CMP or other suitable planarization technique, and then may be patterned as shown in FIG. 14H to form contacts 1428. It can be seen that at this stage a cavity 1430 has been formed in the CMOS wafer with the contacts 1428 serving to at least partially define the cavity. The contacts 1428 (which in some embodiments may represent a single contact forming a closed contour) function as sidewalls of the cavity 1430 in the embodiment illustrated and, as will be further appreciated from consideration of FIG. 14K, create a standoff between the electrode 1416 and a membrane overlying the cavity 1430.

[0101] As shown in FIGs. 141- 14 J, a second wafer 1431 may be bonded to the CMOS wafer. In general, the second wafer may be any suitable type of wafer, such as a bulk silicon wafer, a silicon-on-insulator (SOI) wafer, or an engineered substrate including a polysilicon or amorphous silicon layer with an insulating layer between a single crystal silicon layer and the polysilicon or amorphous silicon layer. In the embodiment illustrated, the second wafer 1431 may include four layers including a base layer or handle layer 1432, insulating layer 1434, layer 1436, and layer 1438. The second wafer 1431 may be used to transfer layers 1436 and 1438 to the CMOS wafer for forming a membrane over cavity 1430, and thus may be referred to herein as a transfer wafer.

[0102] As a non- limiting example of suitable materials making up the second wafer 1431 , the base layer 1432 may be a silicon layer (e.g., single crystal silicon), the insulating layer 1434 may be Si0₂ and may represent a buried oxide (BOX) layer, and layer 1436 may be silicon. In some embodiments, the layer 1436 may be degeneratively doped silicon phosphide (SiP+). In some embodiments, the layer 1436 may be polysilicon or amorphous silicon, though other embodiments may utilize single crystal silicon. The layer 1438 may be formed of a material suitable for bonding to the contacts 1428 on the CMOS wafer. For example, the contacts 1428 and layer 1438 may be formed of the same material. In some embodiments, the contacts 1428 and layer 1438 may be formed of TiN.

[0103] The process used for bonding the second wafer 1431 to the CMOS wafer 1400 may be a low temperature bonding process, for example not exceeding 450° C. In some embodiments, the temperature of the bonding process may be between approximately 200° C and 450° C, between approximately 300° C and approximately 400° C, any temperature(s) within those ranges, any other temperature described herein for low temperature bonding, or any other suitable temperature. Thus, damage to the metallization layers on the CMOS wafer, and any ICs on the CMOS wafer, may be avoided.

[0104] The wafer bonding process may be one of various types. In some embodiments, the wafer bonding may be direct bonding (i.e., fusion bonding). Thus, the wafer bonding may involve energizing respective surfaces of the CMOS and second wafers and then pressing the wafers together with suitable pressure to create the bond. A low temperature anneal may be performed. While fusion bonding represents one example of a suitable bonding technique, other bonding techniques may alternatively be used, including for example bonding two wafers through the use of one or more intermediate layers (e.g., adhesive(s)). In some embodiments, anodic or plasma assisted bonding may be used.

[0105] The bonding illustrated in FIGs. 14I-14J may result in the second wafer 1431 being monolithically integrated with the CMOS wafer 1400. Thus, the two may form a unitary body in some situations.

[0106] A membrane may then be formed from the second wafer 1431. The second wafer 1431 may be thinned from the backside. Such thinning may be performed in stages. For example, mechanical grinding providing coarse thickness control (e.g., 10 micron control) may initially be implemented to remove a relatively large amount of the bulk wafer. In some embodiments, the thickness control of the mechanical grinding may vary from coarse to fine as the thinning process progresses. Then, CMP may be performed on the backside, for example to get to a point close to the layer 1436. Next, a selective etch, such as a selective chemical etch, may be performed to stop on the layer 1436. Other manners of thinning are also possible. [0107] Thus, as shown in FIG. 14K, the base layer or handle layer 1432 and insulating layer 1434 may be removed. A membrane 1440 formed of the layer 1436 and layer 1438 may remain. The membrane may be any suitable thickness TM, non-limiting examples of which are described below. In some embodiments, the layer 1436 may be etched or otherwise thinned to provide a desired membrane thickness.

[0108] Various features of the structure illustrated in FIG. 14K are noted. First, the structure includes a sealed cavity 1430 which is sealed by the membrane 1440. Also, the sidewalls of the cavity are conductive, i.e., the contacts 1428 are conductive and form the sidewalls of the sealed cavity. In this respect, the contacts 1428 represent a conductive standoff for the membrane 1440 from the surface of the CMOS wafer. The contacts 1428 may be relatively large area electrical contacts and make contact with a relatively large area of the membrane, thus providing a low resistivity electrical path to/from the membrane. For example, the contacts may provide electrical control between the membrane and an IC on the CMOS wafer (e.g., disposed beneath the cavity) which may interact with the membrane to provide/receive electrical signals and thus in some embodiments control operation of the membrane.

[0109] Moreover, it is noted that the membrane 1440 has a first side 1442 proximate the cavity 1430 and a second side 1444 distal the cavity, and that direct electrical contact is made to the first side 1442 via the contacts 1428. The first side 1442 may be referred to as a bottom side of the membrane and the second side 1444 may be referred to as a top side of the membrane. Local connection to the membrane 1440 may be made in this manner, and the membrane 1440 may be connected to integrated circuitry in the CMOS wafer via this connection (e.g., via contact 1418). In some embodiments, an IC may be positioned beneath the cavity 1430 and the conductive path configuration illustrated may facilitate making connection between the integrated circuitry beneath the cavity and the membrane 1440. The configuration of FIG. 14K provides a non- limiting example of an embedded contact to the membrane, in that electrical contact is provided by way of a conductive path in the CMOS wafer (e.g., to contact 1418) rather than a contact made on the second side 1444. Such a configuration may be preferable to making electrical contact on the second side 1444 since any contact on the second side 1444 may (negatively) impact vibration of the membrane 1440.

[0110] Also, it is noted that in the embodiment of FIG. 14K the electrode 1416 is narrower than the cavity 1430. Namely, the electrode 1416 has a width Wl less than a width W2 of the cavity 1430. Such a configuration may be desirable at least in those embodiments in which the cavity has conductive sidewalls (e.g., the contacts 1428) to provide electrical isolation between the sidewalls and the electrode.

[0111] Moreover, it is noted that the structure of FIG. 14K may be altered by not including the layer 1438 in an embodiment. Thus, in an embodiment a direct bond may be formed between contacts 1428 (e.g., formed of TiN) and layer 1436 (e.g., silicon).

[0112] The structure illustrated in FIG. 14K may have any suitable dimensions. Non- limiting examples of dimensions for the membrane 1440 and cavity 1430 are described further below.

[0113] As non-limiting examples, the width W2 of the cavity 1430 may be between Dl approximately 5 microns and approximately 500 microns, between approximately 20 microns and approximately 100 microns, may be approximately 30 microns, approximately 40 microns, approximately 50 microns, any width or range of widths in between, or any other suitable width. In some embodiments, the width may be selected to maximize the void fraction, i.e., the amount of area consumed by the cavity compared to the amount of area consumed by surrounding structures. The width dimension may also be used to identify the aperture size of the cavity, and thus the cavities may have apertures of any of the values described above or any other suitable values.

[0114] The depth may be between approximately 0.05 microns and approximately 10 microns, between approximately 0.1 microns and approximately 5 microns, between approximately 0.5 microns and approximately 1.5 microns, any depth or range of depths in between, or any other suitable depth. If the contacts 1428 are formed of TiN, it may be preferable in such embodiments for Dl to be less than 5 microns, since TiN is commonly formed as a thin film. In some embodiments, the cavity dimensions and/or the membrane thickness of any membrane overlying the cavity may impact the frequency behavior of the membrane, and thus may be selected to provide a desired frequency behavior (e.g., a desired resonance frequency of the membrane). For example, it may be desired in some embodiments to have an ultrasonic transducer with a center resonance frequency of between approximately 20 kHz and approximately 200 MHz, between approximately 1 MHz and approximately 10 MHz, between approximately 2 MHz and approximately 5 MHz, between approximately 50 kHz and approximately 200 kHz, of approximately 2.5 MHz, approximately 4 MHz, any frequency or range of frequencies in between, or any other suitable frequency. For example, it may be desired to use the devices in air, gas, water, or other environments, for example for medical imaging, materials analysis, or for other reasons for which various frequencies of operation may be desired. The dimensions of the cavity and/or membrane may be selected accordingly.

[0115] The membrane thickness TM (e.g., as measured in the direction generally parallel to the depth Dl) may be less than 100 microns, less than 50 microns, less than 40 microns, less than 30 microns, less than 20 microns, less than 10 microns, less than 5 microns, less than 1 micron, less than 0.1 microns, any range of thicknesses in between, or any other suitable thickness. The thickness may be selected in some embodiments based on a desired acoustic behavior of the membrane, such as a desired resonance frequency of the membrane.

[0116] Also, it should be appreciated that the cavity 1430, and more generally the cavities of any embodiments described herein, may have various shapes, and that when multiple cavities are formed not all cavities need have the same shape or size. For example, FIGs. 22A-22D illustrate various potential shapes for cavity 1430 and the other cavities described herein. Specifically, FIGs. 22A-22D illustrate top views of a portion 2200 of a CMOS wafer having cavities 1430 formed therein of various shapes. FIG. 22A illustrates that the cavities 1430 may have a square aperture. FIG. 22B illustrates the cavities 1430 may have a circular aperture. FIG. 22C illustrates the cavities may have a hexagonal aperture. FIG. 22D illustrates the cavities 1430 may have an octagonal aperture. Other shapes are also possible.

[0117] While the portion 2200 is shown as including four cavities, it should be appreciated that aspects of the present application provide for one or more such cavities to be formed in a CMOS wafer. In some embodiments a single substrate (e.g., a single CMOS wafer) may have tens, hundreds, thousands, tens of thousands, hundreds of thousands, or millions of CUTs (and corresponding cavities) formed therein. [0118] FIG. 14K illustrates an ultrasonic transducer which has a membrane 1440 overlying the cavity 1430, wherein the membrane has a substantially uniform thickness. In some embodiments, it may be desirable for the membrane to have a non-uniform thickness. For example, it may be desirable for the membrane to be configured as a piston, with a center portion having a greater thickness than an outer portion of the membrane, non-limiting examples of which are described below.

[0119] Ultrasonic transducers such as that illustrated in FIG. 14K may be used to send and/or receive acoustic signals. The operation of the transducer in terms of power generated, frequencies of operation (e.g., bandwidth), and voltages needed to control vibration of the membrane may depend on the shape and size of the membrane. A membrane shaped as a piston with a center mass-like portion that is connected to a CMOS wafer by a thinner peripheral portion may provide various beneficial operating characteristics.

[0120] Accordingly, an aspect of the present application provides ultrasonic transducers having piston membranes. Such transducers may be formed by wafer bonding processes according to some embodiments of the present application. In general, the thicker center portion of such membranes may be formed on the top side or bottom side of the membrane, and may be formed prior to or after wafer bonding.

[0121] Having thus described several aspects and embodiments of the technology described herein, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be within the spirit and scope of the technology described in the present disclosure. For example, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the embodiments described herein. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described. In addition, any combination of two or more features, systems, articles, materials, kits, and/or methods described herein, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the scope of the present disclosure.

[0122] The above-described embodiments can be implemented in any of numerous ways. One or more aspects and embodiments of the present disclosure involving the performance of processes or methods may utilize program instructions executable by a device (e.g., a computer, a processor, or other device) to perform, or control performance of, the processes or methods. In this respect, various inventive concepts may be embodied as a computer readable storage medium (or multiple computer readable storage media) (e.g., a non- transitory computer memory, one or more floppy discs, compact discs, optical discs, magnetic tapes, flash memories, circuit configurations in Field Programmable Gate Arrays or other semiconductor devices, or other tangible computer storage medium) encoded with one or more programs that, when executed on one or more computers or other processors, perform methods that implement one or more of the various embodiments described above. The computer readable medium or media can be transportable, such that the program or programs stored thereon can be loaded onto one or more different computers or other processors to implement various ones of the aspects described above. In some embodiments, computer readable media may be non-transitory media.

[0123] The terms "program" or "software" are used herein in a generic sense to refer to any type of computer code or set of computer-executable instructions that can be employed to program a computer or other processor to implement various aspects as described above. Additionally, it should be appreciated that according to one aspect, one or more computer programs that when executed perform methods of the present application need not reside on a single computer or processor, but may be distributed in a modular fashion among a number of different computers or processors to implement various aspects of the present application.

[0124] Computer-executable instructions may be in many forms, such as program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Typically the functionality of the program modules may be combined or distributed as desired in various embodiments. [0125] Also, data structures may be stored in computer-readable media in any suitable form. For simplicity of illustration, data structures may be shown to have fields that are related through location in the data structure. Such relationships may likewise be achieved by assigning storage for the fields with locations in a computer-readable medium that convey relationship between the fields. However, any suitable mechanism may be used to establish a relationship between information in fields of a data structure, including through the use of pointers, tags or other mechanisms that establish relationship between data elements.

[0126] When implemented in software, the software code can be executed on any suitable processor or collection of processors, whether provided in a single computer or distributed among multiple computers.

[0127] Further, it should be appreciated that a computer may be embodied in any of a number of forms, such as a rack-mounted computer, a desktop computer, a laptop computer, or a tablet computer, as non-limiting examples. Additionally, a computer may be embedded in a device not generally regarded as a computer but with suitable processing capabilities, including a Personal Digital Assistant (PDA), a smart phone or any other suitable portable or fixed electronic device.

[0128] Also, a computer may have one or more input and output devices. These devices can be used, among other things, to present a user interface. Examples of output devices that can be used to provide a user interface include printers or display screens for visual presentation of output and speakers or other sound generating devices for audible presentation of output. Examples of input devices that can be used for a user interface include keyboards, and pointing devices, such as mice, touch pads, and digitizing tablets. As another example, a computer may receive input information through speech recognition or in other audible formats.

[0129] Such computers may be interconnected by one or more networks in any suitable form, including a local area network or a wide area network, such as an enterprise network, and intelligent network (IN) or the Internet. Such networks may be based on any suitable technology and may operate according to any suitable protocol and may include wireless networks, wired networks or fiber optic networks. [0130] Also, as described, some aspects may be embodied as one or more methods. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0131] All definitions, as defined and used herein, should be understood to control over dictionary definitions and/or ordinary meanings of the defined terms.

[0132] The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[0133] The phrase "and/or," as used herein in the specification and in the claims, should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with "and/or" should be construed in the same fashion, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to "A and/or B", when used in conjunction with open-ended language such as "comprising" can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0134] As used herein in the specification and in the claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase "at least one" refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently "at least one of A and/or B") can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0135] Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having," "containing," "involving," and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Claims

CLAIMS What is claimed is:

1. A device, comprising:

a processor configured to generate an image of an internal feature of a target when the device is positioned at an external surface of the target; and

a display configured to display the image, wherein the device is a portable electronic device.

2. The device of claim 1, wherein the target is a human body or a portion of a human body, and wherein the image is a real-time continuous image of the internal feature of the target.

3. The device of claims 1 or 2, wherein the image is an ultrasound image.

4. The device of any of the preceding claims, wherein the device comprises at least one transducer configured to receive radiation from the target, and wherein the image is generated based at least in part on the radiation received by the at least one transducer.

5. The device of claim 4, wherein the at least one transducer is an ultrasound transducer.

6. The device of any of claims 1-5, wherein the device comprises a body and a removable case that at least partially encloses the body.

7. The portable electronic device of claim 6, wherein the body comprises the imaging interface.

8. The portable electronic device of claims 6 or 7, wherein the body comprises at least one of the one or more processors.

9. The portable electronic device of any of claims 6-8, wherein the case comprises at least one of the one or more processors.

10. The portable electronic device of any of claims 6-9, wherein the case comprises the plurality of imaging elements.

11. The portable electronic device of one of claims 6-10, wherein the case comprises a modular unit comprising the plurality of imaging elements, wherein the case and the modular unit are configured to allow the case to retain the modular unit and wherein the modular unit is also configured for retention by a second case for a second portable electronic device having a different size and/or shape than the first portable electronic device.

12. A portable ultrasound device, comprising:

a plurality of ultrasound elements configured to receive ultrasound radiation reflected by or passing through a target when the ultrasound device is pointed at the target; and

a display configured to display an image of an internal feature of the target based at least in part on the ultrasound radiation received by the plurality of ultrasound elements.

13. The portable ultrasound device of claim 12, further comprising at least one processor configured to render the image based at least in part on the ultrasound radiation received by the plurality of ultrasound elements.

14. A method, comprising;

pointing a portable electronic device at an external surface of a subject; and viewing, on a display of the portable electronic device, an image of an internal feature of the subject while pointing the portable electronic device at the external surface of the subject.

15. The method of claim 14, wherein the portable electronic device comprises a radiation sensor, and wherein the method further comprises receiving, with the radiation sensor, radiation reflected by or passing through the subject, and creating the image of the internal feature based at least in part on the radiation received by the radiation sensor.

16. The method of claim 15, wherein the radiation comprises ultrasound signals.

17. A portable electronic device that renders within a window on a display of the device an image of an inside of a human body when the device is directed at the body.

18. The portable electronic device of claim 17, wherein the device renders the image when the device is within approximately one meter of the body.

19. The portable electronic device of claims 17 or 18, wherein the image changes to show images representing different body parts as the device is moved relative to the body.

20. The portable electronic device of any of claims 17-20, wherein the image is three- dimensional image.

21. A portable electronic device comprising:

a plurality of imaging elements configured to receive radiation signals transmitted through or reflected by an imaging target;

an imaging interface; and

one or more processors configured to receive one or more sensing signals from at least one of the plurality of imaging elements, and to render an image of the imaging target for display through the imaging interface based at least in part on the one or more sensing signals.

22. The portable electronic device of claim 21, wherein the plurality of imaging elements are ultrasound imaging elements that are configured to receive ultrasound signals.

23. The portable electronic device of claims 21 or 22, wherein the plurality of imaging elements comprise a plurality of ultrasound transducers.

24. The portable electronic device of any of claims 21-23, wherein the plurality of imaging elements comprise an array of ultrasound transducers.

25. The portable electronic device of any of claims 21-24, wherein the plurality of imaging elements are configured to receive a plurality of radiation signals transmitted through an imaging target.

26. The portable electronic device of claim 25, further comprising a second plurality of imaging elements configured to transmit the plurality of radiation signals to the plurality of imaging elements.

27. The portable electronic device of any of claims 21-26, wherein the plurality of imaging elements are configured to receive radiation signals reflected by an imaging target.

28. The portable electronic device of any of claims 21-27, wherein the portable electronic device comprises a smart phone.

29. The portable electronic device of any of claims 21-28, wherein the portable electronic device comprises a tablet computer.

30. The portable electronic device of any of claims 21-29, wherein the one or more processors are configured to render text, a graphic, and/or other information associated with the image of the imaging target for simultaneous display with the image.

31. The portable electronic device of any of claims 21-30, further comprising memory configured to store data for use by the one or more processors to identify or characterize one or more structures or objects within the image.

32. The portable electronic device of claim 31, wherein the data comprises image data associated with at least one of an organ, artery, vein, tissue, bone, and/or other bodily content or part.

33. The portable electronic device of claim 31 or 32, wherein the data comprises image data associated with at least one of a shape, color, texture, cellular characteristic, and/or tissue characteristic of an imaged structure or object.

34. The portable electronic device of any of claims 31-33, wherein the data comprises data associated with one or more abnormalities in an imaged structure or object.

35. The portable electronic device of any of claims 21-34, wherein the portable electronic device comprises a body and a removable case that at least partially encloses the body.

36. The portable electronic device of claim 35, wherein the body comprises the imaging interface.

37. The portable electronic device of claim 35 or 36, wherein the body comprises at least one of the one or more processors.

38. The portable electronic device of any of claims 35-37, wherein the case comprises at least one of the one or more processors.

39. The portable electronic device of any of claims 35-38, wherein the case comprises the plurality of imaging elements.

40. The portable electronic device of any of claims 35-39, wherein the case comprises a modular unit comprising the plurality of imaging elements, wherein the case and the modular unit are configured to allow the case to retain the modular unit and wherein the modular unit is also configured for retention by a second case for a second portable electronic device having a different size and/or shape than the first portable electronic device.