Backing with integrated ground and signal conductors for an ultrasound transducer

Abstract

To provide a transducer array system in which energy loss is reduced and contrast resolution is improved, a backing, and a method for forming the backing for an acoustic transducer.SOLUTION: In the transducer array 132, the signal conductor 170 and the ground conductor 140 are integrated as part of the backing block 180. A groove extending only partially into the backing block 180 is filled to constitute a ground conductor. Between the transducer elements 135 and the backing block, the signal conductors 170 are integrated into the backing block to replace a flexible circuit or flexible circuit material layer between the PZT layer 130 and the backing block, resulting in less energy loss and improved contrast resolution.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION The presently disclosed embodiments relate to an ultrasound transducer. [Background technology]

[0002] A typical ultrasound transducer includes a piezoelectric (PZT) layer laminated to a backing block. A ground sheet and flexible circuit may be laminated between the PZT layer and the backing block. The ground sheet and flexible circuit materials introduce acoustic energy loss and reduce contrast resolution due to reflections from acoustic mismatch. Summary of the Invention

[0003] By way of preamble, the preferred embodiments described below include methods, systems, backings, and components related to ultrasound transducers. Signal and ground wires are integrated as part of the backing block. In one approach, grooves that extend only partially into the backing block are filled to provide a ground path. The intervening layer (e.g., flexible circuit) between the transducer elements and the backing block is replaced with integrated signal and ground wires, thus resulting in less energy loss and better contrast resolution.

[0004] In a first aspect, a transducer array system is provided, wherein a backing includes an acoustic energy attenuating material, a ground conductor integrated with the acoustic energy attenuating material, and a signal conductor integrated with the acoustic energy attenuating material, the ground conductor and the signal conductor connecting to an array of transducer elements.

[0005] In a second aspect, a backing for an ultrasonic transducer is provided. A block of acoustically attenuating material is provided. A ground conductor is located within a first groove in the block. A plurality of signal conductors are located within the block.

[0006] In a third aspect, a method is provided for forming a backing for an acoustic transducer. A groove is formed in an acoustically attenuating material. A first conductor is deposited in the groove. A ground path is connected to the first conductor. A signal line is formed in the acoustically attenuating material. The signal line is separated from the first conductor. A signal path is connected to the signal line.

[0007] Further aspects and features are outlined below in exemplary embodiments. Each aspect and / or feature may be used in various combinations. An aspect and / or feature in one environment (e.g., a system, backing, or method) may be used in another environment.

[0008] The present invention is defined by the claims, and nothing in this section should be construed as a limitation on those claims. Further aspects and advantages of the present invention are described below in connection with preferred embodiments, and may be later claimed independently or in combination. Different embodiments may or may not achieve different objectives or advantages. [Brief explanation of the drawings]

[0009] The components and drawings are not necessarily to scale, but rather have been exaggerated to illustrate the principles of the present invention. In the drawings, like reference characters indicate corresponding parts throughout the various views. [Figure 1] 1A and 1B are cross-sectional and perspective views, respectively, of an example of a transducer stack using a backing with integrated signal and ground wires. [Figure 2] 2A and 2B are cross-sectional and perspective views, respectively, of another example of a transducer stack using a backing with integrated signal and ground wires. [Figure 3] 3A and 3B are cross-sectional and perspective views, respectively, of another example of a transducer stack using a backing with integrated signal and ground wires. [Figure 4]FIG. 1 is a perspective view of an embodiment of a backing block with integrated signal and ground conductors. [Figure 5] FIG. 1 is a perspective view of an embodiment of a backing block with integrated signal and ground conductors. [Figure 6] FIG. 1 is a perspective view of an embodiment of a backing block with integrated signal and ground conductors. [Figure 7] FIG. 1 is a perspective view of an embodiment of a backing block with integrated signal and ground conductors. [Figure 8] 1 is a flow chart of one embodiment of a method for forming a backing with integrated signal and conductor lines and forming a transducer having the backing. Detailed Description of the Drawings and Presently Preferred Embodiments

[0010] The backing block structure includes signal and ground lines. This structure does not require an intervening metal layer for the signal and ground lines between the transducer elements and the backing block. By forming grooves in the backing block and filling the grooves with a conductive material, the signal and ground lines are implemented in place of conventional signal flexible circuits and ground metal sheets. The signal and ground lines are arranged to match the distribution of the elements in the array, such as in a one-dimensional (1D) or multi-dimensional arrangement.

[0011] The integrated ground and signal wires within the backing eliminate the performance degradation caused by intervening metal layers, thereby reducing costs and improving acoustic performance. Furthermore, this backing block structure effectively dissipates heat because the heat source, the piezoelectric ceramic, is directly bonded to the signal and ground wires on the backing block surface. The width and depth of the ground wires filled with conductive material can be adjusted to optimize acoustic and thermal design.

[0012] 1A and 1B show a cross-sectional view and a perspective view of one embodiment of a transducer array system. The cross-section is in depth-altitude dimensions, with depth corresponding to the vertical direction on the plane of the plane and altitude corresponding to the horizontal direction on the plane of the plane. The elements 135 of the array 132 are distributed along the azimuth dimension (the azimuth direction). The transducer array system includes a backing block 180 with integrated ground conductors 140 and signal conductors 170.

[0013] Transducer array systems are used for ultrasound transducer probes, such as handheld probes for scanning from outside the patient, and intracavity (e.g., TEE or TTE) or catheter-based probes for scanning from inside the patient. The systems include a one-dimensional or multi-dimensional transducer array 132. As a multi-dimensional array 132, the array 132 can be a 1.25, 1.5, 1.75, or 2D array with a distribution of elements 135 in both azimuth and elevation.

[0014] The transducer array system includes matching layers 100, 120, a wraparound electrode 150, an array layer (e.g., a piezoelectric (PZT) layer 130), and an acoustic backer (a backing block of acoustically attenuating material) 180. Additional or different layers, or fewer layers, may be included, such as including an integrated circuit or chip connected to the backing layer and / or excluding one of the matching layers 100, 120. In some examples, a lens and / or housing is provided around the transducer array system or adjacent to the second acoustic matching layer 100. In other examples, a layer of flexible circuit material connects to the backing block 180 opposite the PZT layer 130. The transducer array system and corresponding probes are formed using the method of FIG. 8 or another method.

[0015] Matching layer 100 and matching layer 120 are quarter-wave thick layers of material. While multiple layers can be used to provide a gradation in acoustic impedance, in other embodiments, only one matching layer is provided. Second matching layer 100 provides an acoustic impedance transition between the patient, lens, or other material and first matching layer 120. Similarly, first matching layer 120 provides an acoustic impedance transition from second matching layer 100 to piezoelectric or other transducer array layer 130.

[0016] The array layer is shown as a PZT layer 130, but may include a first matching layer 120. The PZT layer 130 is a slab or plate of PZT material. Solid PZT may be used. Single crystal or polycrystalline PZT material may be used. In other embodiments, a composite of piezoelectric and epoxy or other polymer is used. Instead of PZT, a microelectromechanical (capacitive film) element 135 may be used. Since the example of a piezoelectric is used here, the array layer is referred to as a PZT layer 130.

[0017] After dicing, the PZT layer 130 forms an array 132 of transducer elements 135. The transducer elements 135 of the array 132 or PZT layer 130 are distributed in a grid pattern in one or two dimensions. As shown in FIG. 1B, the PZT layer 130 can form a 1D array with the transducer elements 135 aligned in a straight or curved line. FIG. 3B shows a multidimensional array 132 in which the elements 135 are distributed in two dimensions (azimuth and elevation). The illustrated multidimensional array 132 is a 1.5D or 1.75D array, although 1.25D and 2D arrays can also be used.

[0018] The transducer array 132 is an array of PZT elements 135. The elements 135 transduce acoustic energy to electrical energy, such as an array of transducer elements 135 formed from PZT material. Cuts separate the elements 135 in the PZT layer 130. The cuts may also separate the first acoustic matching layer 120. In other embodiments, the cuts separate the second matching layer 100. In yet other embodiments, the cuts do not extend through the first acoustic matching layer 120. The array may be flat, concave, or convex.

[0019] Each transducer element 135 of the array includes at least two electrodes. A wrap-around electrode 150 is used to provide one or both of the electrodes. A signal electrode is separated by a cutout along with the PZT layer 130, such as an electrode 165 deposited on the PZT layer 130. The elements 135 transduce electrical and acoustic energy. The wrap-around electrode 150, or a portion thereof, defines a zero volt or ground signal. Electrical energy generated by or provided to the PZT is provided to the electrode 165, which is separated from the ground portion of the wrap-around electrode 150. This signal electrode 165 is separate for each element 135, providing a separate conductive path from the PZT layer 130. The signal electrode 165 connects to a signal conductor 170 in the backing block, forming a signal path to and from the array 132.

[0020] The wrap-around electrode 150 is a deposited conductor (e.g., sputter-deposited or plated) on the PZT layer 130. The wrap-around electrode 150 is deposited on the PZT layer 130, for example, on the top, around the sides, and on at least a portion of the bottom. Cutouts are formed to separate the transducer elements 135, and in some embodiments, separate the signal and ground electrodes. Alternatively, the signal electrode is formed separately from the wrap-around electrode 150. The wrap-around electrode 150 is adjacent to the acoustic array 132 on the opposite side from the backing block 180 (e.g., abutting the elements 135 and / or conductively connected to the PZT layer 130). In alternative embodiments, the wrap-around electrode 150 is not wrapped around the PZT layer 130 and / or is a sheet laid on the PZT layer 130.

[0021] The wrap-around electrode 150, or a portion thereof, provides an electrode for transduction on one side of the PZT layer 130. The wrap-around electrode 150 may include traces, wires, or additional sheets that extend to both sides and / or to the sides of the PZT layer 130 adjacent the backing 180. In the example of FIG. 1, the wrap-around electrode 150 extends through both sides to form a signal electrode with a separate portion forming a ground connection or pad 160. The ground portion of the wrap-around electrode 150 connects with the ground electrode 140 on the backing block 180 to form a ground path for the array 132. In the example of FIG. 2, the wrap-around electrode 150 forms a ground electrode, while a separate signal electrode is formed, formed from or separately from a portion of the wrap-around electrode 150.

[0022] The array 132 and corresponding PZT layer 130 are positioned adjacent to a backing block 180. One side of the backing contacts a side of the array 132 (e.g., by asperity contact or solder). This contact is without a full ground sheet or any intervening flexible circuit material. Other layers, such as bonding material, may separate the PZT layer 130 from the backing block 180.

[0023] The backing block 180 is the backing (backing member) of the ultrasonic transducer. The backing block 180 can be a single molded or formed (e.g., machined) block for all of the elements 135. Alternatively, separate backing blocks 180 are provided for different groups of elements 135.

[0024] The backing block 180 is shaped and sized to fit snugly with the array 132. The dimensions of the backing block 180 along the azimuthal and lateral dimensions of the array 132 can match or exceed the array 132. The depth of the backing block 180 can be greater than one-quarter of the longest wavelength at which the array 132 will be used. In some embodiments, this depth is greater than the depth of the PZT layer 130. The backing block 180 can include protrusions or indentations to mate with the PZT layer 130. Epoxy or other bonding or adhesive can be used to connect the backing block 180 to the PZT layer 130 with micro-asperity contact. Clips or other structures can be added to bond or connect the backing block 180 to the array 132. After alignment, the backing block 180 (e.g., an acoustic absorber mold block) is bonded or secured to the PZT layer 130.

[0025] The backing block 180 is an acoustic absorber. It is formed from epoxy, other thermosetting or thermoplastic polymers, or other acoustic absorbers. This acoustic attenuation material can be a single material (e.g., cured epoxy) or a composite of different materials. Different materials can be mixed, such as a composite backing. While the matrix or base material is epoxy, other binders, such as elastomers, can be used for the acoustic attenuation material. The backing block 180 is formed with a supporting structure of cured epoxy, such as an epoxy having thermosetting and thermoplastic components mixed together to chemically cure. Heat, pressure, or other environmental controls can be used to form the cured epoxy. Optional fillers, such as for modifying acoustic attenuation, can be mixed with the epoxy before curing.

[0026] The backing block 180 includes one or more integrated ground conductors 140. The ground conductors 140 are integrated with the acoustic energy attenuating material (e.g., the epoxy block that forms the backing block 180).

[0027] One or more grooves are formed in the backing block 180. Alternatively, one or more grooves are cut or diced into the block. The grooves have any shape, such as a "U" or "V" shape in cross section. This shape may vary. The width and / or depth may be the same or different throughout the groove. The depth of the grooves may be only partially within the backing block 180, i.e., the grooves do not extend from the side on which they are formed to the opposite side. The grooves may be on one side of the block 180 and have a depth that does not extend the full length from that side to the opposite side. Alternatively, the grooves and corresponding ground conductors 140 extend between the two sides.

[0028] The grooves are formed in one or more sides of the backing block 180. Figures 1A and 1B show one groove on one side, where the groove extends the entire side. Shorter lengths may also be used.

[0029] Figures 1A and 1B show a single groove formed in the center of the elevation dimension of array 132. Figures 2A and 2B show a single groove extending in the azimuthal dimension off-center in elevation. Figures 3A and 3B show two parallel grooves in the azimuthal dimension, offset to either side in the elevation dimension. Other arrangements of a single groove may also be used. Other arrangements of multiple grooves, either parallel or non-parallel, may also be used.

[0030] The ground conductor 140 is formed by filling the groove with a conductive material. Any conductive material can be used, such as E-solder, other solders, graphite, silver epoxy, or metals (e.g., copper or stainless steel). The conductive material is poured into the groove and allowed to harden. Alternatively, the conductive material can be cut to fit within the groove and then bonded (e.g., with epoxy) into the groove. The backing block 180 can be molded with the ground conductor 140 or poured around the ground conductor 140 and allowed to harden. A composite of the damping material and the ground conductor 140 can also be bonded to the sidewall of another damping material to form the backing block 180. The integrated ground conductor 140 can replace any of the ground layers between the PZT layer 130 and the backing block 180.

[0031] The grooves and resulting ground conductor 140 may be tailored for acoustic attenuation, thermal conductivity, and / or other considerations. The width, shape, depth, and / or conductive material used may be selected to provide the desired thermal conductivity and / or acoustic attenuation. Figure 4 shows an example of a ground conductor 140 having one width and depth. Figure 5 shows another example of a wider and shallower ground conductor 140.

[0032] The ground conductor 140 forms a ground path through the backing block 180 from the wrap-around electrode 150, which forms the ground electrode of the array 132. Using wire bonding, micro-asperity contacts, or other electrical connections, the ground conductor 140 connects to a wire and / or system ground. The ground conductor 140 integrated into the backing block 180 forms at least a portion of the path to ground for the ground electrode (e.g., the wrap-around electrode 150) of the array 132. More than one path may also be provided, such as in an example where multiple ground conductors 140 (see FIGS. 3A and 3B) are used.

[0033] The ground conductor 140 replaces the sheet of metal between the array 132 and the backing block 180. The ground conductor 140 may also provide a thermal path from the array 132 for heat dissipation.

[0034] The backing block 180 also integrates one or more signal conductors 170. The signal conductors 170 are integrated with an acoustic energy attenuating material. Multiple signal conductors 170 are formed, such as one or two per transducer element 135. The signal conductors 170 connect to the signal electrodes 165 of the array 132 and form separate signal paths to and from the elements 135 for connection to an ultrasound imaging system. The signal paths extend through the backing block 180 following the signal conductors 170.

[0035] A groove is formed for signal conductor 170. The groove may be formed as described above for ground conductor 140 or by another method. The groove may be a via drilled through backing block 180, a groove cut into backing block 180, and / or a molded groove formed when backing block 180 is cured.

[0036] The grooves may be filled to form signal conductors 170. For example, E-solder, other solder, or silver epoxy is poured or placed into the grooves and allowed to harden to form signal conductors 170. Such grooves may also be cuts made by dicing to create signal conductors from a sheet or plate of conductive material. The cuts may or may not be filled with epoxy.

[0037] In some embodiments, the grooves and corresponding signal conductors 170 are formed on the outside of the backing block 180. Figures 1A and 1B show the signal conductors 170 on the side. In other embodiments, the grooves and corresponding signal conductors 170 are formed on the interior of the backing block 180. Figures 2A and 2B show an example. For internal signal conductors 170, the grooves (e.g., vias) are filled or epoxy is cured around the signal conductors 170. The signal conductors 170 may be any of the materials used for the ground conductors 140.

[0038] Other processes may be used to form the internal signal conductors 170 in any desired pattern. One example is shown in FIG. 6. A block of acoustically attenuating material has grooves cut into two sides. These grooves are filled to form the signal conductors 170. The block is then cut, and the two exposed sides of the signal conductors 170 are placed opposite each other to form the pattern of signal conductors 170 shown in FIG. 6. FIG. 7 shows another example. Layers of backing material with signal conductors 170 formed on them are stacked and bonded to form the desired pattern for the signal conductors 170. Other processes may be used, such as supporting the signal conductors 170 in a frame, filling the frame with epoxy, and curing.

[0039] The signal conductors 170 formed on the sides of the acoustically attenuating material can be used in that arrangement, or portions of the material can be cut out and laminated in another arrangement as a backing block 180. In one approach to forming the signal conductors 170 on the sides of a backing block, a sheet of conductive material is deposited, such as a gold sheet, by laying down a foil or by deposition. The sheet is then diced to form the individual signal conductors 170. In another approach, a plate of conductive material is bonded to the acoustically attenuating material. The plate is then diced to form the individual signal conductors 170 in rod form. As another approach, grooves are cut into the acoustically attenuating material and the signal conductors 170 are placed in the grooves (e.g., by curing a conductive fluid, bonding a solid conductor into the groove, etc.).

[0040] The signal conductors 170 extend parallel from one side to the other of the backing block 180. Non-parallel configurations may also be used, such as varying the pitch of the signal conductors 170 from one pitch on the array 132 side to another pitch for connection to a flexible circuit and / or integrated circuit. The signal conductors 170 may extend to sides other than the opposite side.

[0041] The signal conductors 170 are electrically connected, for example via micro-asperity contacts, to the electrodes 165 of the transducer elements 135 of the array 132. The distribution of the signal conductors 170 exposed on one surface of the backing block 180 matches the distribution of the transducer elements 135 and / or the electrodes 165 of the elements 135.

[0042] Signal conductors 170 are integrated into backing block 180 and replace the conventional flexible circuit or flexible circuit material layer between PZT layer 130 and backing block 180. These signal conductors 170 provide a signal path as well as a thermal path for conducting heat away from array 132.

[0043] Flexible circuits, wire bonds, or other electrical connections extend from the ground conductors 140 and signal conductors 170 of the backing block 180 for further connection to the ultrasound system. For example, a flexible circuit material having pads and metal traces is bonded to the backing block 180 on the side opposite the array 132 with micro-asperity contacts. Wire jumpers or wire bonds connect the ground conductors 140 to the flexible circuit material or another wire. As another example, flip-chip bonding or other connections are made to an integrated circuit to the backing block 180.

[0044] 8 is a flow chart of one embodiment of a method for forming a backing for an acoustic transducer and laminating it to the transducer. The backing is formed with ground and signal lines, eliminating the need for a ground sheet or flexible circuit material between the transducer array and the backing.

[0045] The method forms the array system of Figures 1A, 1B, 2A, 2B, 3A, 3B, or another array system. The method forms the backing of Figures 1-7 or other backings. The method is performed as fabrication of the array system and / or backing. A technician or robot stacks and aligns, such as using guide posts or frames. Ovens, irons, induction solder, presses, and / or flow baths are used for bonding or interconnection. A frame, housing, clamp, or holder is used to define the shape and position within the probe housing.

[0046] Additional or different steps may be used, or fewer steps may be used. For example, step 800 is not required if a pre-fabricated initial block of acoustically attenuating material is used. As another example, steps 840, 850, and / or 860 are not provided. As yet another example, step 810 is not provided if grooves are formed as part of curing in step 800. In other examples, steps of adding matching layers, adding lenses, dicing, adding other probe components, and / or other manufacturing (e.g., grinding) steps are provided. In yet another example, steps of testing components or parts, subassemblies, and / or the entire assembly are provided.

[0047] The steps may be performed in the order shown (top to bottom or numerical order) or in other orders. For example, step 830, step 820, and / or step 800 may be performed simultaneously. As another example, step 850 and / or step 860 may be performed one after the other before step 840.

[0048] In process 800, the backing is cured. Epoxy or other acoustically attenuating material is poured or injected into the mold. The backing is hardened through a chemical reaction with or without the application of heat and / or pressure. This results in a block shaped and sized for the array, or a block shaped and sized for cutting into arrays. The block may also be ground or cut for further shaping and / or sizing.

[0049] The cured block or acoustically attenuating material may have flat and / or curved surfaces without grooves for ground and / or signal conductors. The cured block or backing may include one or more grooves for conductors. For example, a mold may include grooves for ground conductors and / or grooves for signal conductors.

[0050] In step 810, one or more grooves are formed in the acoustically attenuating material. A saw or grinder cuts the grooves into one or more outer surfaces of the block, or a drill cuts grooves as vias through the interior of the block.

[0051] To form signal lines in step 830, grooves can be formed in step 810 as dicing cuts. For example, gold plating or other conductive metal can be deposited in a sheet on the surface of the block. Sputter deposition or foil bonding can be used. The sheet is diced to separate the sheet into individual signal conductors. The grooves are the cuts between the signal lines. In another example, a plate of conductive material (e.g., graphite) is bonded to the block. The plate is then diced to separate the plate into individual signal conductors. The grooves are the cuts between the signal lines. In another example, grooves are cut in a damping material. These grooves are then filled, for example, by adding a fluid or by depositing a solid. The filler material in the grooves is conductive to form the signal lines.

[0052] The grooves are formed at a desired pitch. In one approach, the pitch is the same as the elements of the array. A different pitch can also be used, such as when multiple signal conductors are connected to each element.

[0053] The grooves are formed in step 810 to connect to the ground of each element and / or array for depositing a ground conductor in the groove in step 820. For example, the grooves extend in the azimuthal direction of a 1D, 1.25D, 1.5D, or 1.75D array. The grooves may extend from one side of the block to another to connect to the array. Shorter lengths may also be provided. The groove depth is less than the depth of the entire block, although in other approaches it may extend all the way through the block.

[0054] The width and / or depth of the one or more grooves for the one or more ground conductors may be adjusted or optimized for attenuation and / or thermal conductivity. For example, a smaller width may result in less reverberation and greater attenuation. A larger width may provide a larger thermal conduction path to aid in cooling the array. These considerations are balanced to establish the groove width and / or depth, with or without other considerations (e.g., cost of conductive material).

[0055] In step 820, a conductor is deposited into one or more grooves used for the ground path. For example, the grooves are filled with E-solder, other solder, or silver epoxy. Other fluid conductors may also be deposited. The fluid conductor is allowed to harden or solidify in the groove. Any excess may be scraped off. As another example, a solid conductor sized to fit the groove is placed in the groove and bonded into the groove. As another example, a face sheet or plate is cut to form the ground conductor, and a damping material is applied alongside the ground conductor to form the groove. Other techniques for filling the groove with conductive material may also be used.

[0056] In step 830, signal lines are formed in the acoustically attenuating material. The signal lines are isolated from each other and from the ground conductors. The signal conductors are formed using the same or a different approach than when depositing the ground conductors.

[0057] The signal lines are formed at a desired pitch according to the elements of the array. The distribution of the signal lines on the surface of the backing that contacts the array matches the distribution of the elements in the array. For 1D or 1.25D arrays, the signal lines may be formed only on one or more outer surfaces of the backing. For any array, the signal lines may be formed as vias in the backing or as a combination of vias and lines on the outer surface.

[0058] In one approach, signal lines are formed on the outer surface. The block is then cut at the desired depth from the signal lines to form one or more slabs with signal conductors. The slabs are stacked and joined, with some or all of the signal conductors within the backing block, as shown in Figures 2A, 2B, 3A, 3B, 6, or 7. In the example of Figure 6, the block can be split into two halves, and the two halves can be flipped over so that the signal conductors 170 face each other rather than opposite each other. The halves are then joined. In the example of Figure 7, after the signal lines are formed, multiple slabs of the same or different widths are cut out and stacked to provide a distribution of signal lines 170. Alternatively, vias are drilled into the block as internal grooves in the desired pattern. The vias are then filled with a conductive material.

[0059] The signal and ground wires are integrated into the backing. This integration provides the signal and / or ground wires to run on and / or through the surface of the backing. The signal and / or ground wires can be prevented from extending beyond the surface of the backing, such as by depositing and planarizing a damping material. Alternatively, the signal and / or ground wires can be integrated with or part of the backing block while extending from the damping material. The signal and ground wires are formed in or within the backing block for the transducer probe, rather than using a separate layer.

[0060] In step 840, an array of transducer elements is stacked onto a backing block. The array may include matching layers, ground planes, electrodes, and / or other components. The components bonded together are stacked onto the backing. Alternatively, each layer may be stacked sequentially in another process. For example, a PZT with deposited conductor and matching layers may be stacked onto a backing, bonded, diced, and then another matching layer may be stacked and bonded.

[0061] The array is formed by dicing the PZT layers and signal electrodes, either before or after lamination. The resulting transducer elements are distributed in one or two dimensions. Each element and / or its signal electrode is aligned with a signal conductor on a backing block of acoustically attenuating material. The laminations (stacks) are aligned to provide micro-asperities or solder contacts for electrical paths from the elements through the signal lines. Similarly, the ground electrodes of the array stack are aligned to contact or solder to ground conductors on the backing, providing a ground path from the array through the backing block.

[0062] As part of the stack, the layers are bonded together. Epoxy or other adhesive bonds the layers together. The result is a transducer formed by the array of elements and the acoustically attenuating material behind the array. Integrated signal and ground wires in the acoustically attenuating material are used to transmit electrical signals from the ultrasound imaging system to the array and from the array to the ultrasound imaging system.

[0063] In step 850, a ground path is connected to the ground conductor in the backing. Wirebonding, soldering, micro-asperity contact, or other conductive connection is made from the probe or system ground to a ground wire in the backing to ground the array. A wire, trace on a flexible circuit, or printed circuit board, or other conductor is electrically connected to the ground conductor in the backing block.

[0064] In step 860, signal paths for the probe or ultrasound system are connected to the signal lines in the backing. Any of the connection methods described for step 850 can be used. For example, channels or signal lines in the probe cable connect to the signal lines in the backing via traces of flexible circuit material bonded to the bottom surface of the backing block (opposite the array) by micro-asperity contact.

[0065] Once the ground and signal lines are connected in steps 850 and 860, the array can be used for ultrasound scanning or imaging. The ground and signal paths, including portions that pass through the backing block, are used for imaging.

[0066] The following are exemplary embodiments. These exemplary embodiments combine various aspects or features. Each exemplary embodiment can be combined as provided below or in other combinations. Aspects or features (e.g., systems, backings, or methods) of one type can be combined with or used in conjunction with other types.

[0067] Example embodiment 1: 1. A transducer array system comprising: an array of transducer elements and a backing; The backing is an acoustic energy attenuating material; a ground conductor integrated into the acoustic energy attenuating material; a signal conductor integrated into the acoustic energy attenuation material; A transducer array system, wherein the ground conductor and the signal conductor are connected to the array.

[0068] Example embodiment 2: In the transducer array system of exemplary embodiment 1, The array includes a one-dimensional array in which the transducer elements are distributed in a line.

[0069] Example embodiment 3: In the transducer array system of exemplary embodiment 1 or 2, the array includes a ground electrode connected to the ground conductor; The ground conductor provides a ground path from the ground electrode through the backing.

[0070] Example embodiment 4: In the transducer array system according to any one of exemplary embodiments 1 to 3, the array includes a signal electrode connected to the signal conductor; The signal conductor forms a signal path from the signal electrode through the backing.

[0071] Example embodiment 5: In the transducer array system of any one of exemplary embodiments 1 to 4, The array is connected to the backing without any intervening flexible circuit material.

[0072] Example embodiment 6: In the transducer array system of any one of exemplary embodiments 1 to 5, The acoustic energy attenuating material is composed of a thermoset or thermoplastic polymer.

[0073] Example embodiment 7: In the transducer array system of any one of exemplary embodiments 1 to 6, the array is disposed adjacent to a first side of the backing; The ground conductor is within a groove on the first side of the backing and does not extend to an opposite second side of the backing.

[0074] Example embodiment 8: In the transducer array system of exemplary embodiment 7, The groove has a width at the first side and a depth from the first side, the width and the depth being adjusted for thermal conductivity.

[0075] Example embodiment 9: In the transducer array system of exemplary embodiment 1, the array is disposed adjacent to a first side of the backing; The signal conductor extends from the first side of the backing to a second side of the backing opposite the first side.

[0076] Example embodiment 10: In any one of the transducer array systems according to exemplary embodiments 1 to 9, The signal conductors are constructed from diced sheets of deposited conductive material.

[0077] Example embodiment 11: In any one of the transducer array systems according to exemplary embodiments 1 to 10, The signal conductors consist of conductive material deposited in grooves in the acoustic energy attenuating material.

[0078] Example embodiment 12: In any one of the transducer array systems of example embodiments 1 to 11, The signal conductors consist of plates of conductive material separated into rods.

[0079] Example embodiment 13: In any one of the transducer array systems of example embodiments 1 to 12, the array includes a multidimensional array in which the transducer elements are distributed in two dimensions; the signal conductors have a distribution in the backing that matches the distribution of the transducer elements; The ground conductor is comprised of a plurality of ground conductors on the backing.

[0080] Example embodiment 14: 1. A backing for an ultrasonic transducer, comprising: a block of acoustically attenuating material; a ground conductor in a first groove of the block; a plurality of signal conductors in said block.

[0081] Example embodiment 15: In the backing of the fourteenth exemplary embodiment, The first groove is in a first side of the block.

[0082] Example embodiment 16: In the backing of exemplary embodiment 14 or 15, The signal conductors may include diced rods, diced sheets, or filled vias of conductive material passing through the block.

[0083] Example embodiment 17: 1. A method of forming a backing for an acoustic transducer, comprising: forming grooves in the acoustically attenuating material; depositing a first conductor within the trench; connecting a ground path to the first conductor; forming a signal line in the acoustically attenuating material separate from the first conductor; connecting a signal path to said signal line.

[0084] Example embodiment 18: In the method of example embodiment 17, Forming the grooves includes forming the grooves with a width and / or depth based at least in part on thermal conductivity, the depth of the grooves being less than a depth of the acoustically attenuating material.

[0085] Example embodiment 19: In the method of exemplary embodiment 17 or 18, Forming the signal lines includes (a) depositing a sheet of conductive material and dicing the sheet, (b) connecting plates of conductive material and dicing the plates, or (c) cutting vias through the acoustically attenuating material and filling the vias with conductive material.

[0086] Example embodiment 20: In any one of the methods of exemplary embodiments 17 to 19, further comprising stacking an array of two-dimensionally distributed transducer elements on the acoustically attenuating material; Forming the signal lines includes forming signal lines with a two-dimensional distribution that matches the distribution of the transducer elements.

[0087] Regardless of grammatical usage, individuals of male, female, or other gender identities are included within each term.

[0088] While the present invention has been described with reference to various embodiments, it should be understood that many changes and modifications can be made without departing from the scope of the invention. Accordingly, the foregoing detailed description is to be interpreted as illustrative rather than restrictive, and it is the following claims, including all equivalents, which are intended to define the spirit and scope of the invention.

Claims

1. 1. A transducer array system comprising: an array of transducer elements and a backing; The backing is an acoustic energy attenuating material; a ground conductor integrated into the acoustic energy attenuating material; a signal conductor integrated into the acoustic energy attenuation material; A transducer array system, wherein the ground conductor and the signal conductor are connected to the array.

2. The transducer array system of claim 1 , wherein the array comprises a one-dimensional array in which the transducer elements are distributed in a line.

3. the array includes a ground electrode connected to the ground conductor; The transducer array system of claim 1 , wherein the ground conductor forms a ground path from the ground electrode through the backing.

4. the array includes a signal electrode connected to the signal conductor; The transducer array system of claim 1 , wherein the signal conductor forms a signal path from the signal electrode through the backing.

5. The transducer array system of claim 1 , wherein the array connects to the backing without an intervening flexible circuit material.

6. The transducer array system of claim 1 , wherein the acoustic energy attenuating material is comprised of a thermoset or thermoplastic polymer.

7. the array is disposed adjacent a first side of the backing; 2. The transducer array system of claim 1, wherein the ground conductor is within a groove on the first side of the backing and does not extend to an opposite second side of the backing.

8. 8. The transducer array system of claim 7, wherein the groove has a width at the first side and a depth from the first side, the width and the depth being adjusted for thermal conductivity.

9. the array is disposed adjacent a first side of the backing; The transducer array system of claim 1 , wherein the signal conductors extend from the first side of the backing to a second side of the backing opposite the first side.

10. 10. The transducer array system of claim 1, wherein the signal conductors are constructed from diced sheets of deposited conductive material.

11. 10. The transducer array system of claim 1, wherein the signal conductors are comprised of conductive material deposited in grooves in the acoustic energy attenuating material.

12. 10. The transducer array system of claim 1, wherein the signal conductors are comprised of plates of conductive material separated into rods.

13. the array includes a multidimensional array in which the transducer elements are distributed in two dimensions; the signal conductors have a distribution in the backing that matches the distribution of the transducer elements; The transducer array system of claim 1 , wherein the ground conductor is comprised of a plurality of ground conductors on the backing.

14. 1. A backing for an ultrasonic transducer, comprising: a block of acoustically attenuating material; a ground conductor in a first groove of the block; a backing including a plurality of signal conductors in said block;

15. 15. The backing of claim 14, wherein the first groove is in a first side of the block.

16. 15. The backing of claim 14, wherein the signal conductors comprise diced rods, diced sheets, or filled vias of conductive material passing through the block.

17. 1. A method of forming a backing for an acoustic transducer, comprising: forming grooves in the acoustically attenuating material; depositing a first conductor within the trench; connecting a ground path to the first conductor; forming a signal line in the acoustically attenuating material separate from the first conductor; connecting a signal path to said signal line.

18. 20. The method of claim 17, wherein forming the grooves includes forming the grooves with a width and / or depth based at least in part on thermal conductivity, the depth of the grooves being less than a depth of the acoustically attenuating material.

19. 20. The method of claim 17, wherein forming the signal lines comprises: (a) depositing a sheet of conductive material and dicing the sheet; (b) connecting plates of conductive material and dicing the plates; or (c) cutting vias through the acoustically attenuating material and filling the vias with conductive material.

20. further comprising stacking an array of two-dimensionally distributed transducer elements on the acoustically attenuating material; 20. The method of claim 17, wherein forming the signal lines comprises forming signal lines with a two-dimensional distribution that matches the distribution of the transducer elements.

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