Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
  • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
  • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
  • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
  • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
  • B06B1/0607—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements
  • B06B1/0622—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements on one surface
  • B06B1/0629—Square array
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
  • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
  • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
  • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
  • B06B1/0292—Electrostatic transducers, e.g. electret-type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
  • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
  • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
  • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
  • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
  • B06B1/0607—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements
  • B06B1/0622—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements on one surface

Definitions

• This relates generally to ultrasound transducers, and more particularly to combined discrete transmitter circuitry with a separate ultrasonic transducer receiver array.
• Ultrasound transducers exist for transmitting ultrasound waves and detecting a reflection or echo of the transmitted wave. Such devices are also sometimes referred to as ultrasound or ultrasonic transducers or transceivers. Ultrasound transducers have myriad uses, including consumer devices, vehicle safety, and medical diagnostics. In these and other fields, signals detected by the transducer may be processed to determine distance which may be further combined with directional or area processing to determine shape and aspects in connection with two and three dimensional processing, including image processing.
• a micromachined ultrasonic transducer (MUT) array is commonly used in conventional implementations as an ultrasound transducer to perform both the transmission of ultrasonic sounds and the detection of the sound echo.
• Such an array is typically formed using semiconductor processing, whereby an array of micromachined mechanical elements is created relative to the semiconductor substrate. Each array element has a same construction but is separately excitable to transmit a signal and separately readable to detect the signal echo.
• pMUT piezoelectric micromachined ultrasonic transducer
• cMUT capacitive micromachined ultrasonic transducer
• the pMUT array elements function in response to the known nature of piezoelectric materials combined sometimes with a thin film membrane, which collectively generate electricity from applied mechanical strain and, in a reversible process, generate a mechanical strain from applied electricity.
• the cMUT array elements function in response to the known nature of capacitive structure and in combination with an associated membrane, so the elements generate an alternating electrical signal from a change in capacitance caused by vibration of the membrane and, in a reversible process, generate vibration of the membrane from an applied alternating signal across the capacitor.
• acoustic power is a function of the product of pressure, area, and velocity
• the membrane used in a MUT may limit the transmission power because of limitations in sustaining pressure, a relatively small areal coverage on part of the transducer surface, and also due to reduced velocity form non-uniformities across the membrane.
• the number of elements in the MUT array are often increased to achieve greater resolution or other performance, and wire bonding or flex cable are often implemented for interconnectivity to each element, so a large number of elements (e.g., 50x50 or above) creates considerable complexity and cost in a wire bundle or cable to electrically communicate with all elements.
• an ultrasonic transducer has an interposer having electrical connectivity contacts.
• the ultrasonic transducer also has an ultrasonic receiver, including an array of receiving elements, physically fixed relative to the interposer and coupled to electrically communicate with electrical connectivity contacts of the interposer.
• the ultrasonic transducer also has at least one ultrasonic transmitter, separate from the ultrasonic receiver, physically fixed relative to the interposer and coupled to electrically communicate with electrical connectivity contacts of the interposer.
• FIG. 1 illustrates an electrical block diagram of a first side of an ultrasound transducer per the preferred embodiments.
• FIG. 2 illustrates an example, in cross-sectional view, of an element EL that may represent any of the various array elements in FIG. 1.
• FIG. 3 illustrates an electrical block diagram of a second side of the ultrasound transducer of FIG. 1.
• FIG. 4 illustrates a preferred embodiment transmitter.
• FIG. 5 illustrates a cross-sectional view of an electrical block diagram of the ultrasound transducer of FIGS. 1 and 2.
• FIG. 6 illustrates a cross-sectional view of a first alternative preferred embodiment ultrasound transducer.
• FIG. 7 illustrates a cross-sectional view of a second alternative preferred embodiment ultrasound transducer.
• FIG. 8 illustrates a cross-sectional view of a third alternative preferred embodiment ultrasound transducer.
• FIG. 1 illustrates an electrical block diagram of an ultrasound transducer 10 per the preferred embodiments.
• Various matters known in the transducer field may be used to supplement the block and functional description of this document.
• the preferred embodiments, therefore, are described with this understanding and with a concentration on the combination of certain technologies and layouts to achieve an overall ultrasound transducer device that provides advantages over conventional implementations.
• Ultrasound transducer 10 is constructed to include an interposer (or carrier) 12 that provides a structural and electrical foundation for connection to various other devices that are part of the overall device.
• interposer 12 may be a printed or other type of circuit board.
• FIG. 3 illustrates a second side S 2 , which is the opposite of side Si, of interposer 12;
• FIG. 5 illustrates a partial cross-sectional view across interposer 12.
• an ultrasound receiver array 14 which may be constructed as various types of micromachined ultrasonic transducer receiver (MUT) arrays, known and further being developed.
• MUT arrays are commonly used both to transmit ultrasound waves and then detect their resultant echo; however, in the preferred embodiments, while using this same structure, array 14 is functionally used as an ultrasound receiver (i.e., imager), whereas as discussed below different apparatus is used as an ultrasound transmitter.
• Array 14 as shown as being two-dimensional, having rows and columns of elements. For the illustrated embodiment, various elements are labeled with a coordinate shown as EL(row number, column number).
• each element EL(xj ) provides a cavity, shown generally in FIG. 1 as a small square, where the cavity is surrounded by a material from which all the elements are formed; thus, array 14 may be formed by starting with a silicon member (e.g., square or circular) and forming the elements therein. Further, each element usually has a membrane along the bottom of the element cavity that will flex in response to response to receiving an ultrasound wave.
• the total number of row and column elements EL(xj ) are the same and equal to x+1, where preferably x is at least 7, and more preferably x is 49 or greater.
• the number of row elements could differ from the number of column elements.
• array 14 could be linear, whereby its elements are aligned in a single line. And in still another alternative embodiment, array 14 could be annular. Array 14 also may be constructed using various MUT technologies.
• One example embodiment uses a piezoelectric micromachined ultrasonic transducer (pMUT) as array 14.
• An alternatively preferred embodiment uses a capacitive micromachined ultrasonic transducer (cMUT), although a tradeoff is expected to include a higher cost of manufacturing.
• pMUT or cMUT may be constructed relative to a (e.g., silicon) wafer using known and developed semiconductor and micromachining fabrication technologies, so that the elements are formed in part from the wafer material, as further described below.
• FIG. 2 illustrates an example, in cross-sectional view, of an element EL that may represent any of the various elements in of array 14 in FIG. 1.
• Element EL includes a semiconductor surrounding a cavity in three-dimensional space, so the cross-sectional view of FIG. 2 illustrates this as two semiconductor sidewall members MEMsw along with a rear wall member MEM RW shown by and below a dashed line; in the illustrated cross-section, the front wall that otherwise would complete the surround around the element is not visible, but is further included, as also visible in FIG. 1.
• all such members MEM may be formed or result, such as by directionally etching from a surface of a semiconductor substrate or wafer, thereby creating respective cavities enclosed by surrounding semiconductor material, referred to herein as sidewall, front wall, and rear wall members for sake of reference.
• the members MEM are therefore the height of the original semiconductor substrate, with a usual contemporary example being 400 microns. Further therefore, with such a structure, preferably the cavities of each element are generally of the same size and shape. The design of cavity dimensions for acoustic performance is known.
• An element membrane ELMEM is a layer adjacent one end of all the members and contiguous over the cavity.
• element membrane ELMEM is in the range of 2 to 10 microns thick and extends across numerous different elements (e.g., across the entire array). Therefore, the drawings are not to scale, as the element membrane ELMEM is virtually indiscernible to view, as compared to the 400 microns or so of the members MEM.
• membrane ELMEM is formed as an insulator (e.g., silicon dioxide or silicon nitride), as such materials are common in semiconductor manufacturing.
• insulator e.g., silicon dioxide or silicon nitride
• Another preferable attribute of element membrane ELMEM, as achieved by the indicated insulator materials, is being inert to chemicals, where such insulators are inert to a variety of common chemicals.
• Membrane ELMEM is a mechanical structural element that sustains pressure from fluids (e.g., air) that transmit acoustic signals, so for each element, the pressure sustained in the cavity is received by the portion of membrane ELMEM under the cavity.
• Adjacent to element membrane ELMEM is a conductive layer providing a first electrode ELELECI, which is preferably a metal layer in the range of 0.1 to 1 micron thick.
• First electrode ELELECI also is not illustrated to scale, relative to the members MEM. Electrode ELELECI also preferably extends across numerous different elements (e.g., across the entire array). Alternatively, each element can have a separate electrode ELELECI that is electrically isolated from other elements.
• first electrode ELELECI Adjacent to first electrode ELELECI is a piezoelectric film layer EL PZ F, which as its name suggest is a piezoelectric layer, and it is the range of 0.1 to 2 microns thick (also not shown to scale relative to members MEM).
• Piezoelectric film layer EL PZ F also preferably extends across numerous different elements (e.g., across the entire array), but its flexure under the cavity of an individual element is represented by electrical signals to detect a measure of ultrasound wave receipt by that element.
• each element can have a disjoint piezoelectric film layer EL PZF SO to further isolate electrical signals generated between different elements.
• Adjacent piezoelectric film layer EL PZF is a conductive layer providing a second electrode EL ELE C 2 , which is preferably a metal layer in the range of 0.1 to 1 micron thick (also not shown to scale relative to members MEM). Second electrode EL ELE C 2 does not apply across multiple elements, but instead is sized to be less than the cavity for a given cell except for a portion of that electrode that extends beyond the width of the cavity to provide an interconnect, as further detailed below. For example, therefore, electrode EL ELE C 2 may have dimensions in the range of 10% to 80% of the cavity area.
• a first conductive contact ELC TI may be a metal formed through an opening created in piezoelectric film layer EL PZF , to reach a portion of first electrode EL ELE C I , and a second and separate conductive contact EL CT2 is connected to EL ELE C 2 -
• first conductive contact ELC TI is provided to electrically communicate first electrode EL ELE C I
• a second conductive contact ELC T2 is provided to electrically communicate second electrode EL ELE C 2 , as interconnects to an interposer, as detailed below. Electrodes EL ELE C I and EL ELE C 2 are capacitively coupled.
• each element of array 14 is operable to receive an ultrasonic reflection and, due to its structure and materials, provide an electrical signal representative of the received reflection.
• the first electrode EL ELE C I may be connected to a reference potential such as ground, and the voltage on second electrode EL ELE C 2 of any element may be electrically sensed relative to the reference, with that difference representing the flexure of piezoelectric film layer EL PZF , in response to receiving an ultrasonic wave.
• additional circuitry described below, is connected to separately access each such element so that any combination of respective elements signals may be processed to further develop information from the received reflections.
• FIG. 3 illustrates side S 2 of interposer 12.
• physically attached to side S 2 are three separate electrical and operational blocks, including a receive (RX) analog-front-end (AFE) 16, an ultrasonic transmitter 18, and a transmit (TX) driver 20.
• RX receive
• AFE analog-front-end
• TX transmit
• RX AFE 16 is preferably an integrated circuit and includes analog signal conditioning circuitry, such as operational amplifiers and filters that provide a configurable electronic functional block for interfacing the analog signals provided by elements in ultrasound receiver array 14 to an external (e.g., digital) circuit, such as an outside processor (e.g., microcontroller, digital signal processor, microprocessor).
• an external circuit such as an outside processor (e.g., microcontroller, digital signal processor, microprocessor).
• an outside processor e.g., microcontroller, digital signal processor, microprocessor
• Transmitter 18 includes the actuator for generating the ultrasonic sound waves, independent of, and apart from, receiver array 14.
• a MUT (such as may be implemented in receiver array 14) is used in some conventional implementations as a transmitter; however, in the preferred embodiments, the ultrasonic transmission functionality is provided by independent apparatus.
• transmitter 18 may be constructed from various technologies, known or ascertainable.
• transmitter 18 is shown in a perspective view in FIG. 4.
• transmitter 18 is a single element ultrasonic transmitter, preferably constructed using bulk piezoelectric ceramic; in this regard, FIG.
• FIG. 4 illustrates a transmitter with a generally circular cross-section and having a single plate piezoelectric element 18 PE made of piezoelectric ceramic, such as lead zirconate titanate (PZT) or single crystal lead magnesium niobate-lead titanate solid solution (PMN- PT), sandwiched by two electrodes to couple to electrical excitations.
• PZT lead zirconate titanate
• PMN- PT single crystal lead magnesium niobate-lead titanate solid solution
• the preferred embodiment implements bulk ceramics for transmitting ultrasound waves, which thereby afford much greater power as compared to certain other types of transmitters, such as if a MUT were used for the transmitter.
• a thicker bulk ceramic can sustain greater voltage and allow more electric power converted through strain energy, as compared to MUT technology.
• TX driver 20 is included in the preferred embodiment inasmuch as the power and noise requirements are likely to differ as between the lower power needs of RX AFE 16 and the higher power needs of transmitter 18.
• TX driver 20 is preferably an integrated circuit and includes circuitry that provides level shifting as between the lower power available for RX AFE 16 and the higher power needed for transmitter 18. Such level shifting may include control/regulation of current and voltage within a varying range of input voltages.
• FIG. 5 illustrates a cross-sectional view across interposer 12 and other items described above, where additional details are now observed.
• each of array 14, RX AFE 16, transmitter 18, and TX driver 20 is physical and electrically interconnected to interposer 12.
• each of these items is constructed using bumping metallization or other flip chip bumps such as solder or plated copper so that contacts, such as via miniature ball grid arrays (BGA), may be used to both physically and electrically connect each respective circuit to conductors on interposer 12.
• array 14 is shown to have a respective BGA 14 B GA to connect to side Si of interposer 12 to electrodes of array 14, where as shown in FIG.
• each of RX AFE 16, transmitter 18, and TX driver 20 has a respective BGA 16 B GA, 18 B GA E , and 20 B GA to connect to side S 2 of interposer 12.
• the relatively large number of elements of array 14 will give rise to a shorter pitch and greater connectivity density among BGA 14 B GA, as compared to that of arrays BGA 16 B GA, 18 B GA, and 20 B GA-
• the former may be in the range of usually less than 250 microns, or less than 100 microns, or even less than 50 micron, while the latter is in the range of usually greater than 400 microns.
• the BGA (or other connectors) between transmitter 18 and interposer 12 are positioned to be out of the path of the acoustic wave transmitted by transmitter 18, which in the orientation of FIG. 5 is upward.
• Transmitter 18 also may be electrically connected to interposer 12 with other package footprints, such as used in quad flat packages (QFP), quad flat no-leads packages (QFN), or other outline packages such small outline integrated circuit (SOIC), or through-hole connectors.
• QFP quad flat packages
• QFN quad flat no-leads packages
• SOIC small outline integrated circuit
• FIG. 5 also illustrates that an acoustic couplant layer (or multiple layers) 14ACI is formed upward between and vertically beyond the substrate members (i.e., in the cavities) of array 14, and an acoustic couplant layer (or multiple layers) 14AC2 is formed between interposer 12and array 14.
• an acoustic couplant layer (or multiple layers) 18 A c is formed along transmitter 18 and more specifically on the transmitter surface that faces interposer 12 (recall, such an acoustic couplant layer 18AC is also shown in FIG. 4).
• Each acoustic couplant layer may be formed by flowing the couplant during a dispense step, while then curing the layer to the positions shown.
• Each such acoustic couplant provides an acoustic matching layer to more readily communicate ultrasonic sounds and sensitivity from the structure to the medium in which transducer 10 is located. Accordingly, acoustic couplant layer 18AC facilitates the transmission of ultrasonic waves from transmitter 18 in the direction of interposer 12, through array 14, and upward in the perspective of FIG. 5. Similarly, acoustic couplant layer 14 A c will facilitate the receipt by array 14 of the reflected echo of waves transmitted by transmitter 18.
• array 14 as a pMUT receiver has an additional benefit that both sides of the silicon receiver can serve as a sound port and receive acoustic signals; in contrast, if array 14 is implemented as a cMUT receiver, then preferably it further includes "through silicon via” (TSV) construction to send electric signals from the front side imager to the backside interconnect.
• TSV through silicon via
• transducer 10 Given the preceding, the general operation of transducer 10 should be readily understood.
• an enabled power supply e.g., battery, not shown
• TX driver 20 applies sufficient level adjusting to drive transmitter 18 with relatively high power.
• Transmitter 18 then emits ultrasonic waves, such as sound or other vibrations at an ultrasonic frequency, and such emissions are optimized by acoustic couplant 18AC, in the direction to and through interposer 12 and through and beyond array 14.
• receiver array 14 After the passage of a time window for receiving an expected response, receiver array 14, lower-powered yet more resolution-sensitive relative to single-element transmitter 18, receives an echo of the transmitted signal, and the piezoelectric (or capacitive) nature of array 14 converts those echoes into proportional electrical signals. These element signals are then conditioned by RX AFE 16 for further processing, either by circuitry also on interposer 12 or connected via an interface of RX AFE 16.
• an array 14 for receiving permits design adjustments for size and pitch determined by resolution needs to optimize sensing
• one or more single-element transmitter 18 (as described below) will be sufficient in various applications for focus and/or synthetic aperture transmissions and may be further optimized for transmitting.
• each of array 14 and transmitter 18 may be independently optimized to adjust its own respective function, with little or no effect on the opposite function of the other.
• the apparatus therefore requires only a relatively higher voltage signal path for the transmitter(s) apparatus/functionality, while a low voltage signal path is sufficient for the receiver apparatus/functionality.
• additional benefits may be realized in various alternative preferred embodiments.
• FIG. 6 illustrates a cross-sectional view of an alternative preferred embodiment ultrasound transducer 10AI.
• Transducer 10AI generally shares much of the same construction and functionality as transducer 10 described above, with the difference that transducer 10AI includes transmitters, shown in FIG. 4 as preferably three such transmitters, namely, transmitters 18.1, 18.2, and 18.3.
• Each transmitter 18.x is physically and electrically connected to side S 2 of interposer 12, in a manner comparable to transmitter 18 for transducer 10.
• each transmitter 18.x in FIG. 4 is preferably a single element transmitter, having a respective acoustic couplant layer 18AC along it and facing interposer 12, and electrically each transmitter is connected to interposer 12 via a respective BGA or other formats (not expressly numbered in the Figure).
• transducer 10AI the operation and functionality of transducer 10AI is comparable to transducer 10, whereby each transmitter 18.x emits ultrasonic waves in the direction of its respective acoustic couplant, through interposer 12 and into the desired medium; such waves may be reflected by a nearby object, with the echo received and sensed by array 14.
• TX driver 20 (or related circuitry) is operable to excite any or transmitter 18.x with controlled phase delay with respect to the other transmitter(s) for beam steering.
• the echo of such transmissions, as received by array 14, and with signals therefrom communicated via RX AFE 16, may be processed to determine some measure of directionality as a result of beam steering, rather than having a singular direction of emission/detection as in the case of a single transmitter.
• FIG. 7 illustrates a cross-sectional view of an alternative preferred embodiment ultrasound transducer 10 ⁇ 2 ⁇ Transducer 10A2 generally shares much of the same construction and functionality as transducer 10 described above, with the difference that transducer 10A2 also includes transmitters, shown in FIG. 7 as preferably two such transmitters 18.1 and 18.2, and in addition each such transmitter 18.x is connected to side Si of interposer 12. Further in this regard, a respective acoustic couplant layer 18AC is formed along a side of each of transmitters 18.1 and 18.2, but in FIG. 7 such layer is on the surface of the transmitter that is opposite of the surface that is electrically connected to interposer 12. Thus, in the perspective of FIG.
• each transmitter 18.1 and 18.2 is connected, via a respective BGA, to interposer 12, while along the upper surface of each transmitter 18.1 and 18.2 is a respective acoustic couplant layer 18AC- [0034]
• transducer 10A2 is comparable to transducer 10AI, whereby each transmitter 18.x emits ultrasonic waves in the direction of its respective acoustic couplant.
• emissions for transducer 10A2 do not pass through interposer 12 (or array 14), so any signal dissipation that otherwise may be caused by such signal passage is avoided.
• having multiple transmitters allow beam steering.
• the placement of the transmitters may be important for this purpose. Generally, transmitters may be placed at constant spacing for ease of use.
• FIG. 8 illustrates a cross-sectional view of an alternative preferred embodiment ultrasound transducer 10 ⁇ 3 ⁇
• Transducer 10A3 combines aspects illustrated and discussed above with respect to transducers IOAI and 10 ⁇ 2 ⁇
• transducer 10A3 includes three transmitters 18.1, 18.2, and 18.3.
• a difference is that two of the transmitters in FIG. 8 are positioned on surface Si, as was the case for transducer 10A2, while the third transducer is positioned on surface S 2 , as was the case for the transmitters in transducers 10 and IOAI.
• transducer 10A 3 should be readily understood to combine aspects described above, with the additional directional resolution of three transmitters, while recognizing that some dissipation of the emission from transmitter 18.2 may occur as its emitted signal is directed through interposer 12 and array 14.
• various preferred embodiments provide improvements to ultrasound transducers by providing such a transducer that combines discrete transmitter circuitry with a micromachined ultrasonic transducer receiver array.
• conventional ultrasonic transducers seek to accomplish both transmission and imaging (sensing echo) with a same array, and usually greater sensitivity and resolution is sought by increasing the number of elements in such an array to a great degree.
• Such efforts increase complexity and cost.
• the use of such arrays may tend to decrease range, given the physical limitations of thin films and small imager elements.
• the preferred embodiments provide numerous benefits. For example, signal processing between transmission and detection can be re-optimized for best transmission beam forming and phase-array imaging.
• the MUT in one mode of operation, can still be used for both receiving signals and transmissions, where for such short distances minimum transmission power is required and low voltage drive would be acceptably provided by RX AVE 16.
• discrete transmitters provide a high achievable transmitted power
• the array receiver provides a high achievable receiving resolution and integrated signal path.
• the transmit and receive paths are decoupled, thereby providing improved signal integrity and optimized overall system sensitivity by handling transmission and sensing separately, namely, removing the need for transmission by the array to thereby provide the ability to maximize the array receiver sensitivity.
• power is likewise separated, so that low voltage may be used with the array to reduce potential noise, maximize individual process capability, and improve potential on-chip coupling problems.
• Costs in the preferred embodiments are also well managed by implementing a low cost transmitter(s) without complicated machining and a smaller receiver than would be necessary as compared to one necessary to size up to transmit power. Still further, flip chip assembly provides a modest interconnect and assembly complexity.
• the preferred embodiments may be implemented in numerous applications, such as: (i) high sensitivity finger print sensor; (ii) intra-vascular Ultrasound Sensor with photo acoustic TX or capability; (iii) ultrasound vein detector; or (iv) ultrasound commuted tomography (CT) or micro-CT, in which the TX element and RX element are not in the same transducer/location.
• the preferred embodiments are thus demonstrated to provide an ultrasound transducer combining discrete transmitter circuitry with a separate ultrasonic transducer receiver array.
• the preferred embodiments have been shown to have numerous benefits, and still others will be further determined.
• adjustments are contemplated to various measures and architectures according to application and other considerations.
• one preferred embodiment may include array 14 as annular in shape; with the various illustrations of alternative transmitter locations, therefore, the annular array could include a transmitter(s) in the middle open area defined by the annulus and/or a transmitter(s) outside the perimeter of the annulus. In this manner, the various transmitters are useful to steer the beam in various x, y, z dimensions.
• another preferred embodiment may include an array with multiple voids, such as areas where no semiconductor member wall material exists, and where each such void includes a respective transmitter.
• illustrated preferred embodiments depict at least one ultrasonic transmitter and a separate ultrasonic receiver both physically connected to the interposer via their respective electrical contacts, in alternative preferred embodiments the physical connection may be separated from the electrical connection, and/or also may be facilitated by some intermediary structure, where in any event the transmitter is affixed, by some member or apparatus, physically relative to the interposer and also by the same or separate structure coupled to electrically communicate with electrical connectivity contacts of the interposer.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transducers For Ultrasonic Waves (AREA)
• Ultra Sonic Daignosis Equipment (AREA)
• Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
• Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)

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