Backing with integrated ground and signal conductors for ultrasonic transducers

Abstract

A backing with integrated ground and signal conductors for an ultrasonic transducer is provided. For the ultrasonic transducer, the signal line and the ground line are integrated as part of a backing block. In one method, a recess extending only partially into a backing block is filled to provide a ground path. Interposition layers (e.g., flex circuits) between transducer elements and backing blocks are replaced by integrated signal lines and ground lines, thus less energy loss and higher contrast resolution.

Description

TECHNICAL FIELD

[0001] This embodiment relates to ultrasonic transducers. BACKGROUND

[0002] This embodiment relates to ultrasonic transducers. A typical ultrasonic transducer includes a piezoelectric (PZT) layer stacked on a backing block. A ground tab and a flex circuit can be stacked between the PZT layer and the backing block. The ground tab and flex circuit material cause loss of acoustic energy and degrade contrast resolution due to reverberation caused by acoustic mismatch. SUMMARY

[0003] By way of introduction, the preferred embodiments described below include methods, systems, backings, and assemblies for ultrasonic transducers. Signal and ground lines are integrated as part of the backing block. In one method, a recess extending only partially into the backing block is filled to provide a ground path. An intermediate layer (e.g., a flex circuit) between the transducer elements and the backing block is replaced by the integrated signal and ground lines, so there is less energy loss and higher contrast resolution.

[0004] In a first aspect, a transducer array system is provided. 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 are connected with an array of transducer elements.

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

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

[0007] Further aspects and features are summarized below in illustrative embodiments. Different aspects and / or features can be used in various combinations. An aspect and / or feature in one context (e.g., a system, a backing, or a method) can be used in another context.

[0008] The invention is defined by the claims appended hereto, and nothing in this section should be interpreted as a limitation on those claims. Additional aspects and advantages of the invention will be discussed below in connection with preferred embodiments, and can be claimed independently or in combination later. Different embodiments can or can not achieve different advantages or objects. BRIEF DESCRIPTION OF DRAWINGS

[0009] The components and appendices are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the application. In addition, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0010] Figure 1A and 1B are cross-sectional and perspective views of an example transducer stack using a backing with integrated signal and ground lines;

[0011] Figure 2A and 2B are cross-sectional and perspective views of another example transducer stack using a backing with integrated signal and ground;

[0012] Figure 3A and 3B are cross-sectional and perspective views of yet another example transducer stack using a backing with integrated signal and ground;

[0013] Figures 4-7 are perspective views of different embodiments of a backing block with integrated signal and ground conductors; and

[0014] Figure 8 is a flowchart of one embodiment of a method for forming a backing with integrated signal and ground lines and forming a transducer with the backing. DETAILED DESCRIPTION

[0015] The backing block structure includes signal and ground lines. This structure avoids the need for intervening metal layers for signal and ground lines between the transducer elements and the backing block. The signal and ground lines are implemented by forming grooves on the backing block and filling the grooves with conductive material, replacing traditional signal flex circuits and ground metal sheets. The signal and ground lines are arranged to match the distribution of the array elements, such as one-dimensional (ID) or multi-dimensional arrangements.

[0016] The integrated ground and signal lines in the backing can reduce cost and improve acoustic performance by avoiding performance degradation from intervening metal layers. In addition, this backing block structure is effective in terms of heat dissipation because the piezoelectric ceramics, which are heat sources, are directly coupled to the signal and ground lines on the surface of the backing block. By setting the width and depth of the ground lines filled with conductive material, the acoustic and thermal design can be optimized.

[0017] Figure 1A and 1B are cross-sectional and perspective views of one embodiment of a transducer array system. The cross-section is in the depth-elevation dimension, where depth is vertical on the drawing sheet, and elevation is horizontal on the drawing sheet. The elements 135 of the array 132 are distributed along the azimuth dimension. The transducer array system includes a backing block 180 with integrated ground conductors 140 and signal conductors 170.

[0018] The transducer array system is used in an ultrasound transducer probe, such as a hand-held probe for scanning from outside a patient's body or from within a body cavity (e.g., TEE or TTE), or a catheter-based probe for scanning from within a patient's body. The system includes 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 elements 135 distributed in both azimuth and elevation.

[0019] The transducer array system includes a matching layer 100, 120, a surround electrode 150, an array layer (e.g., a piezoelectric (PZT) layer 130), and an acoustic backing (a backing block of acoustically attenuating material) 180. Additional, different, or fewer layers can be included, such as including an integrated circuit or chip connected to the backing layer and / or not including one of the matching layers 100, 120. In some examples, a lens and / or a housing are provided around or adjacent to the second acoustic matching layer 100. In other examples, a layer of flexible circuit material is connected to the backing block 180 opposite the PZT layer 130. The transducer array system and corresponding probe are formed using the method of Figure 8 or another method.

[0020] The matching layers 100 and 120 are layers of material of wavelength thickness. Multiple layers of gradually changing acoustic impedance can be used, but in other implementations only one matching layer is provided. The second matching layer 100 provides a transition in acoustic impedance between the patient, lens, or other material and the first matching layer 120. Similarly, the first matching layer 120 provides a transition in acoustic impedance from the second matching layer 100 to the piezoelectric or other transducer array layer 130.

[0021] The array layer is shown as a PZT layer 130, but can include the first matching layer 120. The PZT layer 130 is a thin sheet or plate of PZT material. Solid PZT can be used. Single crystal or polycrystalline PZT material can be used. In other embodiments, a composite of piezoelectric and epoxy or another polymer is used. Microelectromechanical (capacitive membrane) elements 135 can be used instead of PZT. The piezoelectric example is used here, so the array layer will be referred to as a PZT layer 130.

[0022] Once cut, the PZT layer 130 forms an array 132 of transducer elements 135. The array 132 or transducer elements 135 of the PZT layer 130 are distributed in a one- or two-dimensional grid. As shown in Figure 1B the PZT layer 130 can form a ID array, with the transducer elements 135 distributed in a straight or curved line. Figure 3B A multi-dimensional array 132 is shown, with elements 135 distributed in two dimensions (azimuth and elevation). The multi-dimensional array 132 shown is a 1.5 or 1.75D array, but a 1.25 or 2D array can also be used.

[0023] The transducer array 132 is an array of PZT elements 135. The elements 135 convert between acoustic and electrical energy, for example an array of transducer elements 135 formed of PZT material. The cuts separate the elements 135 of the PZT layer 130. The cuts can also separate the first acoustic matching layer 120. In other embodiments, the cuts separate the second matching layer 100. In still other embodiments, the cuts do not extend through the first acoustic matching layer 120. The array is flat, concave, or convex.

[0024] Each transducer element 135 of the array includes at least two electrodes. The surround electrode 150 provides one electrode or is used to form two electrodes. The signal electrode is separated from the PZT layer 130 by the cut, for example an electrode 165 deposited on the PZT layer 130. The element 135 converts between electrical and acoustic energy. The surround electrode 150 or a portion thereof defines a 0 volt or ground signal. Electrical energy generated by or provided to the PZT is provided on the electrode 165 separated from the ground portion of the surround electrode 150. The signal electrode 165 is separate for each element 135, providing a conductive path separate from the PZT layer 130. The signal electrode 165 is connected with a signal conductor 170 of the backing block, forming a signal path to and from the array 132.

[0025] The surround electrode 150 is a deposited conductor on the PZT layer 130 (e.g., sputter deposited or plated). The surround electrode 150 is deposited on the PZT layer 130, for example on at least a portion of the top, around the sides, and the bottom. The cuts are formed to separate the transducer elements 135, and in some implementations, to separate the signal and ground electrodes. Alternatively, the signal electrode is formed separate from the surround electrode 150. The surround electrode 150 is adjacent to the acoustic array 132 on a side opposite the backing block 180 (e.g., against the elements 135 and / or conductively connected to the PZT layer 130). In alternative implementations, the surround electrode 150 does not surround the PZT layer 130 and / or is a sheet placed on the PZT layer 130.

[0026] The surround electrode 150 or a portion thereof provides an electrode for transduction on a side of the PZT layer 130. The surround electrode 150 can have traces, wires, or another sheet that extend on a side of the PZT layer 130 and / or to a side of the PZT layer 130 adjacent to the backing 180. In the example of FIG. 1, the surround electrode 150 extends on a side and forms a signal electrode with separate portions forming ground connections or pads 160. The ground portions of the surround electrode 150 are connected with the ground electrode 140 of the backing block 180 to form a ground path for the array 132. In the example of FIG. 2, the surround electrode 150 forms a ground electrode and a separate signal electrode is formed by a portion of the surround electrode 150 or separately formed.

[0027] Array 132 and corresponding PZT layer 130 are located near backing block 180. One side of the backing is in contact (e.g., rough contact or through solder) with one side of array 132. This contact is without a full ground tab and without any intervening flex circuit material. Other layers can separate PZT layer 130 from backing block 180, such as adhesive material.

[0028] Backing block 180 is a backing for the ultrasonic transducer. Backing block 180 can be a single molded or formed (e.g., machined) block for all elements 135. Alternatively, separate backing blocks 180 are provided for different groups of elements 135.

[0029] Backing block 180 is shaped and sized to mate with array 132. The dimensions of backing block 180 along the azimuthal and lateral dimensions of array 132 can match array 132 or extend beyond array 132. The depth of backing block 180 can be greater than the longest wavelength used by array 132. In some embodiments, this depth is greater than the depth of PZT layer 130. Backing block 180 can include protrusions or recesses for mating with PZT layer 130. Epoxy or other adhesive or glue can be used to connect backing block 180 with PZT layer 130 in rough contact. Clamps or other structures can be added to mate or connect backing block 180 with array 132. Once aligned, backing block 180 (e.g., a molded block of acoustic absorber) is bonded or fixed to PZT layer 130.

[0030] Backing block 180 is an acoustic absorber. Backing block 180 is formed from epoxy, another thermoset or thermoplastic polymer, or another acoustic absorber. This acoustic attenuating material can be one material (e.g., cured epoxy) or a composite of different materials. Different materials can be mixed, such as a composite backing. The base or base material is epoxy, but other adhesives can be used for the acoustic attenuating material, such as elastomers. Backing block 180 is formed from a support structure of cured epoxy, such as epoxy mixed with thermoset and thermoplastic components to chemically cure. Heat, pressure, or other environmental controls can be used to form the cured epoxy. Any fillers, such as fillers to change the acoustic attenuation, can be mixed with the epoxy before curing.

[0031] Backing block 180 includes one or more integrated ground conductors 140. Ground conductors 140 are integrated with the acoustic energy attenuating material (e.g., the block of epoxy forming backing block 180).

[0032] The backing block 180 is formed with one or more grooves. Alternatively, one or more grooves are cut or carved out of the block. The grooves have any shape, such as a cross-section that is “U” shaped or “V” shaped. The shape can vary. The width and / or depth of the entire groove is the same or varies. The depth of the groove is only partially into the backing block 180, so the groove does not extend to the opposite side of the side of the block 180 from which the groove is formed. The groove is on one side of the block 180, and the depth is less than the distance from that side to the opposite side. Alternatively, the groove and the corresponding ground conductor 140 extend between the opposite sides.

[0033] The groove is formed on one or more sides of the backing block 180. Figure 1A and 1B One groove on one side is shown, with the groove extending through the entire side. Smaller extensions can be used.

[0034] Figure 1A and 1B A single groove is shown that is centered along the elevation dimension of the array 132. Figure 2A and 2B A single groove is shown that extends along the azimuth dimension offset from the elevation center. Figure 3A and 3B Two parallel grooves are shown along the azimuth dimension, and offset on opposite sides along the elevation dimension. Other placements of one groove can be used. Other arrangements of multiple grooves with parallel or non-parallel positioning can be used.

[0035] The ground conductor 140 is formed by filling the groove with a conductive material. Any conductive material can be used. For example, electronic solder, other solder, graphite, silver epoxy, or metal (e.g., copper or stainless steel) is used. The conductive material flows into the groove and solidifies. Alternatively, the conductive material is cut to fit the groove, and then bonded (e.g., with epoxy) in the groove. The backing block 180 can be molded or cast with the ground conductor 140 around the ground conductor 140, and then solidified. The composite of the attenuating material and the ground conductor 140 can bond to the sidewalls of other attenuating materials to form the backing block 180. The integrated ground conductor 140 can replace any ground layer between the PZT layer 130 and the backing block 180.

[0036] The groove and the resulting ground conductor 140 can be adjusted for acoustic attenuation, thermal conductivity, and / or other considerations. The width, shape, depth, and / or conductive material used can be selected to provide the desired thermal conductivity and / or acoustic attenuation. Figure 4 An example of a ground conductor 140 with one width and depth is shown. Figure 5 Another example of a ground conductor 140 that is wider and shallower is shown.

[0037] Grounding conductor 140 forms a grounding path from the surrounding electrode 150 of the grounding electrodes forming array 132 through backing block 180. Grounding conductor 140 is connected to a wire and / or system ground using wire bonding, rough contact, or other electrical connections. Grounding conductor 140 integrated into backing block 180 forms at least a portion of the grounding path of the grounding electrodes (e.g., surrounding electrode 150) of array 132. More than one path may be provided, for example, using multiple grounding conductors 140 (see [link to relevant documentation]). Figure 3A and 3B ).

[0038] A ground conductor 140 replaces the metal sheet between array 132 and backing block 180. The ground conductor 140 can also form a heat path from array 132 for heat dissipation.

[0039] The backing block 180 also integrates one or more signal conductors 170. The signal conductors 170 are integrated with an acoustic attenuation material. Multiple signal conductors 170 are formed, for example, one or two signal conductors per transducer element 135. The signal conductors 170 are connected to the signal electrodes 165 of the array 132, forming separate signal paths to and from the element 135 for connection to an ultrasound imaging system. Due to the signal conductors 170, the signal paths extend through the backing block 180.

[0040] A groove is formed for the signal conductor 170. The groove is formed as discussed above for the ground conductor 140 or in another manner. The groove may be a through hole drilled through the backing block 180, a groove cut into the backing block 180, and / or a molded groove formed during the curing of the backing block 180.

[0041] The groove can be filled to form the signal conductor 170. For example, electronic solder, other solder, or silver epoxy resin can be poured or placed in the groove and cured to form the signal conductor 170. The groove can also be a cut formed by cutting to form the signal conductor from a sheet or plate of conductive material. The cut can be filled with or not filled with epoxy resin.

[0042] In some implementations, the groove and the corresponding signal conductor 170 are formed on the outside of the backing block 180. Figure 1A and 1B The signal conductor 170 is shown on the side. In other implementations, the groove and the corresponding signal conductor 170 are formed inside the backing block 180. Figure 2A and 2B An example is shown. For the internal signal conductor 170, the groove (e.g., through-hole) may be filled or epoxy resin may be cured around the signal conductor 170. The signal conductor 170 may be any material used for the ground conductor 170.

[0043] Other processes can be used to form any pattern of the internal signal conductor 170.Figure 6 An example is shown. A block of acoustic attenuating material is cut with grooves on two opposite sides. These grooves are filled to form signal conductors 170. The block is then cut, and the two exposed sides with the signal conductors 170 are placed opposite each other to form… Figure 6 The pattern of signal conductor 170 shown. Figure 7 Another example is shown. Backing material layers with the formed signal conductor 170 are stacked and bonded to form a desired pattern for the signal conductor 170. Other processes can be used, such as supporting the signal conductor 170 in a frame, filling the frame with epoxy resin, and curing.

[0044] The signal conductor 170 formed on the side of the acoustic attenuating material can be used in this arrangement, or it can be cut from some material for stacking with the backing block 180 in another arrangement. In one method for forming the signal conductor 170 on one side of the backing block, a sheet of conductive material is deposited, for example, by placing a foil or by depositing a gold sheet. The sheet is then cut to form individual signal conductors 170. In another method, a conductive material plate is bonded to the acoustic attenuating material. The plate is then cut to form individual signal conductors 170 as rods. As another method, a groove is cut into the acoustic attenuating material and the signal conductor 170 is placed in the groove (e.g., by curing a conductive fluid or by bonding a solid conductor into the groove).

[0045] Signal conductors 170 extend parallel from one side of the backing block 180 to the other. A non-parallel arrangement can be used, for example, changing the spacing of the signal conductors 170 from one spacing on one side of the array 132 to another spacing for connection with flexible circuits and / or integrated circuits. Signal conductors 170 can extend to sides other than the opposite side.

[0046] Signal conductor 170 is electrically connected, for example, to the electrodes 165 of transducer element 135 of array 132 via rough contact. The distribution of signal conductor 170 exposed on one side of backing block 180 matches the distribution of transducer element 135 and / or electrodes 165 of element 135.

[0047] Signal conductors 170 integrated into the backing block 180 replace the conventional flexible circuit or flexible circuit material layer between the PZT layer 130 and the backing block 180. These signal conductors 170 provide signal paths as well as thermal paths for conducting heat away from the array 132.

[0048] For further connection to the ultrasound system, flexible circuitry, wire bonding, or other electrical connections extend from the ground conductor 140 and signal conductor 170 of the backing block 180. For example, flexible circuitry material with pads and metal traces is bonded to the backing block 180 opposite the array 132 in a rough contact manner. Jumpers or bonding wires connect the ground conductor 140 to the flexible circuitry material or another wire. As another example, flip-chip bonding or other connections to the backing block 180 are formed using integrated circuits.

[0049] Figure 8 This is a flowchart of one embodiment of a method for forming a backing for an acoustic transducer and stacking it with the transducer. The backing is formed with ground lines and signal lines, eliminating the need for grounding plates or flexible circuit material between the array in the transducer and the backing.

[0050] This method forms an array system of patterns 1A, 1B, 2A, 2B, 3A, 3B, or another array system. This method forms a backing as shown in Figures 1-7, or another backing. This method is implemented for the fabrication of the array system and / or the backing. Technicians or robots perform stacking and alignment, for example, using guide posts or frames. Ovens, irons, induction brazing machines, presses, and / or wave soldering baths are used for joining or interconnecting. Frames, housings, fixtures, or supports are used for shaping and positioning within the probe housing.

[0051] Additional, different, or fewer actions may be used. For example, in the case of providing a prefabricated initial block of acoustic attenuation material, action 800 is not provided. As another example, actions 840, 850, and / or 860 are not provided. As yet another example, in the case where the groove is formed as part of the curing in 800, action 810 is not provided. In another example, actions are provided for adding a matching layer, adding a lens, cutting, adding other probe components, and / or other manufacturing (e.g., grinding). In yet another example, testing of components or parts, subassemblies, and / or the entire assembly is provided.

[0052] These actions are performed in the order shown (top to bottom or numbered) or other orders. For example, actions 830, 820, and / or 800 may be performed simultaneously. As another example, actions 850 and / or 860 are performed before action 840 and in any order relative to each other.

[0053] In action 800, the backing is cured. Epoxy resin or other acoustic damping material is poured or injected into the mold. The backing cures through a chemical reaction with or without heat and / or pressure. The result is that blocks are shaped and sized for an array, or shaped and sized to be cut into arrays. The blocks can be ground or cut for further shaping and / or sizing.

[0054] The cured block or acoustic attenuating material may have a flat plane and / or curved surface without grooves for grounding and / or signal lines. The cured block or backing may include one or more grooves for conductors. For example, the mold includes grooves for grounding conductors and / or grooves for signal conductors.

[0055] In action 810, one or more grooves are formed in the acoustic damping material. A saw or grinder cuts grooves on one or more outer surfaces of the block. Alternatively, a drill bit cuts grooves as through holes through the interior of the block.

[0056] To form signal lines in action 830, grooves can be formed as cuts in action 810 by cutting. For example, gold plating or other conductive metal is deposited as a sheet on the surface of the block. Sputter deposition or bonding foil can be used. The sheet is cut, separating it into individual signal conductors. Grooves are cuts between signal lines. In another example, a sheet of conductive material (e.g., graphite) is bonded to the block. The sheet is then cut, separating it into individual signal conductors. Grooves are cuts between signal lines. As another example, grooves are cut into an attenuating material. These grooves are then filled, for example, by adding a fluid or placing a solid. The filling material in the grooves is conductive, thus forming signal lines.

[0057] The grooves are formed at a desired spacing. In one approach, the spacing is the same as the number of elements in the array. Larger spacing can be used, for example, when multiple signal conductors are connected to each element.

[0058] To deposit a conductor for grounding in the groove in action 820, a groove is formed in action 810 to connect to the ground of each element and / or array. For example, the groove extends along the azimuth of the array at 1, 1.25, 1.5, or 1.75D. The groove can extend from one side of the block to the other side to connect to the array. Shorter extensions are possible. The depth of the groove is less than the full depth of the block, but in other methods it can extend through the block.

[0059] The width and / or depth of one or more grooves used for the grounding conductor can 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 can provide a larger heat conduction path to help cool the array. These considerations, with or without other considerations (e.g., the cost of conductive materials), are balanced to determine the width and / or depth of the grooves.

[0060] In action 820, a conductor is deposited in one or more recesses for a grounding path. For example, the recesses are filled with electronic solder, other solder, or silver epoxy. Other fluid conductors may be deposited. The fluid conductor cures or solidifies in the recess. Excess conductors may be ground away. As another example, a solid conductor sized to fit the recess is placed in and bonded to it. In yet another example, a surface sheet or plate is cut to form a grounding conductor, and an attenuating material is added next to the grounding conductor to form the recess. Other techniques for filling the recesses with conductive materials may be used.

[0061] In action 830, signal lines are formed in the acoustic attenuation material. The signal lines are separated from each other and from the ground conductor. The signal conductor is formed by depositing the ground conductor using the same or different methods.

[0062] The array-based elements form signal lines at a desired spacing. The distribution of the signal lines on the backing surface of the contact array matches the distribution of the array elements. 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 a combination of vias and lines on the outer surfaces.

[0063] In one method, signal lines are formed on an outer surface. Blocks are then cut from the signal lines at any desired depth to form one or more thin plates with signal conductors. By stacking and bonding these thin plates, some or all of the signal conductors are then located within a backing block, such as... Figure 2A , 2B As shown in 3A, 3B, 6, or 7. In Figure 6 In the example, the block can be divided into two halves, which are then flipped so that the signal conductors 170 are adjacent to each other rather than opposite each other. The two halves are then joined together. Figure 7 In the example, after the signal lines are formed, different thin plates of the same or different widths are cut out, and then the plates are stacked to provide the distribution of the signal lines 170. Alternatively, through-holes are drilled in the blocks as internal recesses at the desired pattern locations. The through-holes are then filled with a conductive material.

[0064] The signal and ground lines are integrated into the backing. This integration provides the signal and / or ground lines on the surface of the backing and / or through the interior of the backing. For example, by depositing attenuating material and planing, the signal and / or ground lines may not extend beyond the surface of the backing. Alternatively, the signal and / or ground lines may extend from the attenuating material while being integrated with or part of the backing block. The signal and ground lines are formed on or within the backing block, rather than using a separate layer for the transducer probe.

[0065] In action 840, an array of transducer elements is stacked on a backing block. This array may include a matching layer, a ground plane, electrodes, and / or other components. Components bonded together are stacked on the backing. Alternatively, different layers may be stacked sequentially using other processes, such as stacking PZT with deposited conductors and matching layers on the backing, bonding, then cutting, and then stacking another matching layer and bonding.

[0066] Before or after stacking, an array is formed by cutting the PZT layers and signal electrodes. The resulting transducer elements are distributed in one or two dimensions. The elements and / or the signal electrodes of the elements are aligned with signal conductors in an acoustic attenuation material backing block. The stack alignment is to provide rough or solder contact for the electrical path from the elements through the signal lines. Similarly, the ground electrodes of the array stack are aligned to contact or solder to the ground conductor in the backing block, providing a ground path from the array through the backing block.

[0067] As part of a stack, the layers are bonded together. Epoxy resin or other adhesives bind the layers together. The result is a transducer formed from an array of elements and acoustic attenuation material behind the array. The integrated signal and ground lines of the acoustic attenuation material are used for communication signals from and to the ultrasound imaging system.

[0068] In action 850, the grounding path is connected to the grounding conductor of the backing block. Wire joints, solders, rough contacts, or other conductive connections are formed from the probe or system ground to the grounding wire in the backing block, thereby grounding the array. Wires, traces, or other conductors of flexible circuits or printed circuit boards are electrically connected to the grounding conductor of the backing block.

[0069] In action 860, the signal path of the probe or ultrasound system is connected to the signal line in the backing. Any connection discussed for action 850 can be used. For example, the channel of the probe cable or the signal line is connected to the signal line in the backing via traces on a flexible circuit material that is in rough contact with the bottom surface of the backing block (the side opposite the array).

[0070] Once the grounding and signal lines are connected in actions 850 and 860, the array can be used for ultrasound scanning or imaging. The grounding and signal paths, including the portion passing through the backing block, are used for imaging.

[0071] The following are illustrative embodiments. These illustrative embodiments outline various aspects or features. Different illustrative embodiments may be combined as provided below, or in other combinations. One type of aspect or feature (e.g., system, backing, or method) may be combined with or used with another type.

[0072] Illustrative Example 1. A transducer array system includes: an array of transducer elements; and a backing including an acoustic attenuation material, a ground conductor integrated with the acoustic attenuation material, and a signal conductor integrated with the acoustic attenuation material, wherein the ground conductor and the signal conductor are connected to the array.

[0073] Illustrative Example 2. The transducer array system according to Illustrative Example 1, wherein the array comprises a one-dimensional array, and wherein the transducer elements are linearly distributed.

[0074] Illustrative Example 3. A transducer array system according to any one of the illustrative examples 1-2, wherein the array includes a ground electrode connected to the ground conductor, and wherein the ground conductor forms a ground path from the ground electrode through the backing.

[0075] Illustrative Example 4. A transducer array system according to any one of the illustrative examples 1-3, wherein the array includes signal electrodes connected to the signal conductor, and wherein the signal conductor forms a signal path from the signal electrodes through the backing.

[0076] Illustrative Example 5. A transducer array system according to any one of the illustrative examples 1-4, wherein the array is connected to the backing without the intervention of flexible circuit material.

[0077] Illustrative Example 6. A transducer array system according to any one of the illustrative Examples 1-5, wherein the acoustic attenuation material comprises a thermosetting or thermoplastic polymer.

[0078] Illustrative Example 7. A transducer array system according to any one of the illustrative Examples 1-6, wherein the array is located near a first side of the backing, and the grounding conductor is located in a groove on the first side of the backing without extending to a second opposite side of the backing.

[0079] Illustrative Example 8. According to the transducer array system of Illustrative Example 7, the groove has a width on the first side and a depth extending from the first side, the width and the depth being adjusted for thermal conductivity.

[0080] Illustrative Example 9. The transducer array system of claim 1, wherein the array is located near a first side of the backing, and the signal conductor extends from the first side of the backing to a second side opposite to the first side.

[0081] Illustrative Example 10. A transducer array system according to any one of the illustrative Examples 1-9, wherein the signal conductor comprises a diced piece of deposited conductor material.

[0082] Illustrative Example 11. A transducer array system according to any of the illustrative Examples 1-10, wherein the signal conductor comprises a conductive material deposited in a groove of the acoustic attenuation material.

[0083] Illustrative Example 12. A transducer array system according to any of the illustrative examples 1-11, wherein the signal conductor comprises a plate of conductive material separated into rods.

[0084] Illustrative Example 13. A transducer array system according to any one of the illustrative examples 1-12, wherein the array comprises a multidimensional array, wherein the transducer elements are distributed in two dimensions, wherein the signal conductors have a distribution in the backing that matches the distribution of the transducer elements, and wherein the ground conductors comprise a plurality of ground conductors in the backing.

[0085] Illustrative Example 14. A backing for an ultrasonic transducer, the backing comprising: a block of acoustic attenuating material; a grounding conductor in a first recess of the block; and a plurality of signal conductors in the block.

[0086] Illustrative Example 15. The backing according to Illustrative Example 14, wherein the first groove is on the first side of the block.

[0087] Illustrative Example 16. A backing according to any of the embodiments in Illustrative Examples 14-15, wherein the signal conductor comprises a dicing bar, a dicing blade, or a conductive material filling a through-hole through the block.

[0088] Illustrative Example 17. A method for forming a backing for an acoustic transducer, the method comprising: forming a groove in an acoustic attenuating material; depositing a first conductor in the groove; connecting a ground path to the first conductor; forming a signal line in the acoustic attenuating material, the signal line being separate from the first conductor; and connecting a signal path to the signal line.

[0089] Illustrative Example 18. According to the method of Illustrative Example 17, forming the groove includes forming a groove having a width and / or depth at least partially based on thermal conductivity, the depth of the groove being less than the depth of the acoustic attenuating material.

[0090] Illustrative Example 19. The method according to any of the illustrative Examples 17-18, wherein forming a signal line includes: (a) depositing a conductive material sheet and dicing the sheet; (b) connecting a conductive material plate and dicing the plate; or (c) cutting through a via through the acoustic attenuation material and filling the via with conductive material.

[0091] Illustrative Example 20. The method according to any of the embodiments of Exemplary Examples 17-19 further includes: stacking an array of transducer elements distributed in two dimensions on the acoustic attenuation material; wherein forming signal lines includes forming signal lines having a two-dimensional distribution that matches the distribution of the transducer elements.

[0092] In this patent application, nouns and pronouns referring to people generally do not specify a particular gender.

[0093] While the invention has been described above 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. Therefore, the foregoing detailed description is intended to be illustrative rather than restrictive, and it should be understood that the spirit and scope of the invention are intended to be defined by the appended claims, including all equivalents.

Claims

1. A transducer array system comprising: an array of transducer elements; and a backing comprising 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 connected with the array.

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

3. The transducer array system of claim 1, wherein the array comprises a ground electrode connected with the ground conductor, and wherein the ground conductor forms a ground path through the backing from the ground electrode.

4. The transducer array system of claim 1, wherein the array comprises a signal electrode connected with the signal conductor, and wherein the signal conductor forms a signal path through the backing from the signal electrode.

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

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

7. The transducer array system of claim 1, wherein the array is located near a first side of the backing, the ground conductor is located in a recess on the first side of the backing without extending to a second, opposite side of the backing.

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

9. The transducer array system of claim 1, wherein the array is located near a first side of the backing, the signal conductor extends from the first side to a second side of the backing, the second side opposite the first side.

10. The transducer array system of claim 1, wherein the signal conductor comprises a cut piece of deposited conductor material.

11. The transducer array system of claim 1, wherein the signal conductor comprises a conductive material deposited in a recess of the acoustic attenuating material.

12. The transducer array system of claim 1, wherein the signal conductor comprises a plate of conductive material separated into sticks.

13. The transducer array system of claim 1, wherein the array comprises a multi- dimensional array, wherein the transducer elements are distributed two-dimensionally, wherein the signal conductor has a distribution in the backing that matches the distribution of the transducer elements, and wherein the ground conductor comprises a plurality of ground conductors in the backing.

14. A backing for an ultrasonic transducer, the backing comprising: a block of acoustic attenuating material; a ground conductor in a first recess of the block; and a plurality of signal conductors in the block.

15. The backing of claim 14, wherein the first recess is on a first side of the block.

16. The backing of claim 14, wherein the signal conductors comprise cut sticks, cut pieces, or conductive material filled through-holes through the block.

17. A method for forming a backer for an acoustic transducer, the method comprising: forming a recess in an acoustically attenuating material; depositing a first conductor in the recess; connecting a ground path to the first conductor; forming a signal line in the acoustically attenuating material, the signal line being separate from the first conductor; and connecting a signal path to the signal line.

18. The method of claim 17, wherein forming a recess comprises forming a recess having a width and / or depth based at least in part on thermal conductivity, the recess having a depth less than a depth of the acoustically attenuating material.

19. The method of claim 17, wherein forming a signal line comprises: (a) depositing a sheet of conductive material and cutting the sheet; (b) connecting a plate of conductive material and cutting the plate; or (c) slitting a through-hole through the acoustically attenuating material and filling the through-hole with conductive material.

20. The method of claim 17, further comprising: stacking an array of transducer elements in a two-dimensional distribution on the acoustically attenuating material; wherein forming a signal line comprises forming a signal line having a two-dimensional distribution matching the distribution of the transducer elements. ​

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