Patent Description:
In some present ultrasonic transducers, electrical energy is converted into ultrasonic waves, i.e., above <NUM> kilohertz (kHz), and vice versa. Ultrasonic transducers are sometimes referred to as ultrasonic transmitters, receivers, or transceivers, depending on their application. An ultrasonic transducer can include a membrane that oscillates in response to an alternating current (AC) signal applied to the ultrasonic transducer, or in response to a received ultrasonic signal. When transmitting, the membrane oscillates to produce an ultrasonic wave that propagates away from the membrane. When receiving, the membrane oscillates in a measurable manner, producing an AC signal in the ultrasonic transducer.

Ultrasonic transducers are used in many fields for testing. For example, in medical fields, ultrasonic transducers are used for medical imaging. In other fields, ultrasonic transducers are used for nondestructive testing. Generally, ultrasonic transducers transmit an ultrasonic wave into an object. As the ultrasonic wave propagates through and reaches various features of the object, the ultrasonic wave can be partially reflected. The ultrasonic transducer detects the reflections. The reflections are interpreted based on the transmitted ultrasonic wave and the lapsed time between the transmission and receiving the reflections to analyze certain features of the object. Testing systems utilizing ultrasonic transducers can produce images, graphic displays, or measurements from the collected data.

Single-element ultrasonic transducers can produce an ultrasonic wave characterized by its wavelength and its beam width, and propagating in a single direction. In some instances, ultrasonic testing, single-element ultrasonic transducers offer limited utility, because of their narrow unidirectional beam. In such instances, single-element ultrasonic transducers may be physically scanned, moved, or turned to sweep the ultrasonic beam over the area of the object being tested. In some instances, multiple ultrasonic transducers can be arranged in a phased array. Phased array arrangements vary widely according to their application, arrangements including one-dimensional (<NUM>-D) arrays, two-dimensional (<NUM>-D) arrays, and three-dimensional (<NUM>-D) arrays. Phased array ultrasonic transducers can facilitate electronically sweeping the ultrasonic beam over the area of the object being tested. Each ultrasonic transducer in the phased array can be individually controlled in amplitude, frequency, and phase, allowing the phased array ultrasonic transducer to produce a directed ultrasonic beam that can be electronically swept over the area of the object being tested.

During operation, the ultrasonic energy emitted by the phased array ultrasonic transducer can be generally concentrated in the main beam. However, some amount of ultrasonic energy can be emitted in other, less desirable directions. Some conventional ultrasonic transducers and phased array ultrasonic transducers are manufactured such that the transducer membrane is in direct contact with a printed circuit board (PCB). The PCB includes an integrated circuit (IC) that carries the AC signals to and from each ultrasonic transducer in the phased array. Certain phased arrays require multiple PCB layers to provide sufficient contacts for the numerous ultrasonic transducers. Consequently, the PCB may absorb at least some of the undesired ultrasonic energy, reducing performance of the PCB itself and the phased array ultrasonic transducer.

<CIT> discloses an acoustic transducer assembly including a backing block of acoustically attenuating material having conductors extending through the block. <CIT> discloses an integrated backing layer for an ultrasonic matrix array transducer. <CIT> relates to a piezoelectric composite comprising piezoelectric ceramic material surrounded by a piezoelectrically passive polymer matrix, for use in an ultrasonic transducer. <CIT> discloses a stack of acoustic elements coupled to an integrated circuit.

The present disclosure describes ultrasonic transducers and techniques for manufacturing a phased array ultrasonic transducer with integrated bonding wire. As described more fully below, embodiments of the present disclosure provide a bonding wire structure that connects the ultrasonic transducer to the printed circuit board. The bonding wire structure is surrounded by an ultrasonic damping material that reduces the amount of ultrasonic energy that reaches the printed circuit board. Such a bonding wire structure and damping material is manufactured using additive manufacturing techniques. For example, a bonding wire structure can be 3D-printed using a conductive material. A resin-based damping material is then applied to the bonding wire structure and cured, resulting in an integrated bonding wire structure. The integrated bonding wire structure can then be trimmed and mounted between ultrasonic transducers and a printed circuit board. Other embodiments are within the scope of the present disclosure.

Embodiments of the present disclosure relate to phased array ultrasonic transducers. More specifically, the phased array ultrasonic transducers described herein include an integrated bonding wire structure that can couple the ultrasonic transducers to a printed circuit board. The bonding wire structure is manufactured by additive manufacturing techniques, sequentially depositing layers of a conductive material to form multiple bonding wire elements on top of a structural base. A damping material is then added to the bonding wire structure and cured. The damping material can be trimmed to design dimensions, including removal of the structural base for the bonding wire structure. The membrane for the ultrasonic transducers may be laminated on a first face of the damping material, and a printed circuit board can be laminated to an opposite face.

<FIG> is a cross-sectional diagram of an embodiment of a conventional phased array ultrasonic transducer <NUM>. Phased array ultrasonic transducer <NUM> includes transducers <NUM>, <NUM>, and <NUM>. Phased array ultrasonic transducer <NUM> may include additional or fewer transducers (not shown), however, for clarity, <FIG> illustrates only a portion of phased array ultrasonic transducer <NUM>. Transducers <NUM>, <NUM>, and <NUM> can include respective membranes <NUM>, <NUM>, and <NUM> that oscillate in response to an alternating current (AC) signal applied to transducers <NUM>, <NUM>, and <NUM>, and/or in response to a received ultrasonic wave. Transducers <NUM>, <NUM>, and <NUM> may be embodied by any suitable ultrasonic transducers, including a piezoelectric transducers and capacitive transducers.

Transducers <NUM>, <NUM>, and <NUM> are coupled to a printed circuit board (PCB) <NUM> through respective contacts <NUM>, <NUM>, and <NUM>. PCB <NUM> includes multiple circuits (not shown) for carrying signals to and from each of transducers <NUM>, <NUM>, and <NUM>. Voids between each of transducers <NUM>, <NUM>, and <NUM> and PCB <NUM> can be filled by a filler material <NUM>. PCB <NUM> may include a rigid PCB or a flexible PCB, and may further include one or more PCB layers to accommodate the necessary circuits and contacts for transducers <NUM>, <NUM>, and <NUM>.

Phased array ultrasonic transducer <NUM> includes a damping material <NUM> fixed to a side, for example, the back side of PCB <NUM>. Properties of damping material <NUM> further define the operating characteristics of phased array ultrasonic transducer <NUM>, including frequency response and sensitivity. During operation, each of transducers <NUM>, <NUM>, and <NUM> produces an ultrasonic wave <NUM> that propagates away from respective membranes <NUM>, <NUM>, and <NUM>. Likewise, some of the generated ultrasonic energy is directed into PCB <NUM> and damping material <NUM>. Such ultrasonic energy is illustrated as ultrasonic wave <NUM>. Damping material <NUM> attenuates ultrasonic wave <NUM>.

<FIG> is a diagram of an exemplary <NUM>-D phased array ultrasonic transducer <NUM>. Phased array ultrasonic transducer <NUM> includes a plurality of ultrasonic transducers <NUM> arranged in a row <NUM>. Phased array ultrasonic transducer <NUM>, in certain embodiments, may be formed at least partially by dicing a larger rectangular transducer. During operation, the ultrasonic beam generated by phased array ultrasonic transducer <NUM> is steerable in a single plane.

<FIG> is a diagram of an exemplary <NUM>-D phased array ultrasonic transducer <NUM>. Phased array ultrasonic transducer <NUM> includes a plurality of ultrasonic transducers <NUM> arranged in rows <NUM> and columns <NUM> to form a grid. During operation, the ultrasonic beam generated by phased array ultrasonic transducer <NUM> can be steerable in three dimensions.

<FIG> is a diagram of an exemplary <NUM>-D phased array ultrasonic transducer <NUM>. Phased array ultrasonic transducer <NUM> includes a plurality of ultrasonic transducers <NUM> arranged in rows <NUM> and columns <NUM>, also forming a grid. Each of rows <NUM> of ultrasonic transducers <NUM> is curved, allowing the generated ultrasonic beam to conform to the curve or the geometry of an object being tested. The generated ultrasonic beam is further steerable in three dimensions. In other embodiments, rows <NUM> of ultrasonic transducers <NUM> may be curved in one direction and change to another, for example, in an "S" configuration or another shape to enable the ultrasonic beam to conform to the curve or the geometry of the object being tested.

<FIG> is a diagram of the exemplary phased array ultrasonic transducer <NUM> with an integrated bonding wire structure <NUM>. Integrated bonding wire structure <NUM> includes a plurality of bonding wire elements <NUM>, <NUM>, and <NUM> respectively coupled between PCB <NUM> and transducers <NUM>, <NUM>, and <NUM>. Bonding wire elements <NUM>, <NUM>, and <NUM> conduct AC signals from PCB <NUM> to transducers <NUM>, <NUM>, and <NUM>. Transducers <NUM>, <NUM>, and <NUM> are respectively coupled to bonding wire elements <NUM>, <NUM>, and <NUM> through contacts <NUM>, <NUM>, and <NUM>.

In certain embodiments, bonding wire elements <NUM>, <NUM>, and <NUM> are formed in various shapes. For example, in one embodiment, integrated bonding wire structure <NUM> includes a plurality of conductive cones, where the broad end is coupled to a transducer, such as transducers <NUM>, <NUM>, and <NUM>, and the narrow end is coupled to a PCB, such as, for example, PCB <NUM>. In another embodiment, integrated bonding wire structure <NUM> includes a plurality of conductive cylinders.

Phased array ultrasonic transducer <NUM> includes a damping material <NUM> that surrounds and is interposed with bonding wire elements <NUM>, <NUM>, and <NUM>. Voids between each of transducers <NUM>, <NUM>, and <NUM> and damping material <NUM> are filled by a filler material <NUM>. During operation, each of transducers <NUM>, <NUM>, and <NUM> produce an ultrasonic wave <NUM> that propagates away from respective membranes <NUM>, <NUM>, and <NUM>. Likewise, some of the generated ultrasonic energy is directed into damping material <NUM>, where it is attenuated before reaching PCB <NUM>. Such ultrasonic energy is illustrated as ultrasonic wave <NUM>. Damping material <NUM> defines a first face <NUM> to which transducers <NUM>, <NUM>, and <NUM> are coupled. Damping material <NUM> further defines a second face <NUM>. PCB <NUM> is coupled to second face <NUM>. Phased array ultrasonic transducer <NUM> includes first face <NUM> and second face <NUM> that is positioned opposite first face <NUM>.

<FIG> is a perspective diagram of an exemplary 3D-printed integrated bonding wire structure <NUM> for phased array ultrasonic transducer <NUM> (shown in <FIG>). Integrated bonding wire structure <NUM> is composed of a conductive material, such as, for example, and without limitation, copper, tin, aluminum, tungsten, or gold. Integrated bonding wire structure <NUM> includes a plurality of bonding wire elements <NUM> arranged in a grid <NUM>. Grid <NUM> may have any suitable spacing for a given application. For example, in one embodiment, bonding wire elements <NUM> are arranged on a <NUM> millimeter (mm) grid. In another embodiment, for example, bonding wire elements <NUM> are arranged on a <NUM> grid.

In some embodiments, each of bonding wire elements <NUM>, such as bonding wire elements <NUM>, <NUM>, and <NUM> (shown in <FIG>) is configured to couple an ultrasonic transducer to a PCB, such as PCB <NUM> (shown in <FIG> and <FIG>). In other embodiment, one or more bonding wire elements are configured to couple with an ultrasonic transducer PCB, such as PCB <NUM>. Bonding wire elements <NUM> each may include a conductive column extending from a structural base <NUM>. Integrated bonding wire structure <NUM> is formed using an additive manufacturing technique, sometimes referred to as 3D printing. More specifically, integrated bonding wire structure <NUM> is formed by depositing sequential layers of conductive material to form each of bonding wire elements <NUM>. Such techniques include, for example, and without limitation, metal powder injection, fused deposition modeling, fused filament fabrication, robocasting, stereolithography, digital light processing, powder bed and inkjet head 3D printing, electron beam melting, selective laser melting, selective heat sintering, selective laser sintering, direct metal laser sintering, laminated object manufacturing, directed energy deposition, and electron beam freeform fabrication. The conductive material is deposited in layers until a desired length of the conductive columns is reached. In certain embodiments, the conductive column length is <NUM>. The length of the conductive columns may vary based on the application of phased array ultrasonic transducer <NUM>. The shape of each of bonding wire elements <NUM> may also vary based on the application. In certain embodiments, bonding wire elements <NUM> are round. In alternative embodiments, bonding wire elements <NUM> may be rectangular, conical, or any other suitable shape. Further, bonding wire elements <NUM> can be formed to match the geometry of the transducer surface. In certain embodiments, bonding wire elements <NUM> follow a defined <NUM>-D spline.

<FIG> is a perspective diagram of an exemplary integrated bonding wire structure <NUM>, including damping material <NUM> and integrated bonding wire structure <NUM>. Damping material <NUM> is added to integrated bonding wire structure <NUM> and can then be cured into a solid. Damping material <NUM> surrounds integrated bonding wire structure <NUM> and is interposed with bonding wire elements <NUM>. Damping material <NUM> may include, for example, and without limitation, a resin based material, i.e., a curable resin. When cured, damping material <NUM> forms a coating that absorbs and attenuates ultrasonic energy. In alternative embodiments, damping material <NUM> includes, for example, and without limitation, a plastic based material, an injectable material, tungsten powder, carbon powder, and other suitable materials for attenuating ultrasonic energy.

<FIG> is a perspective diagram of an exemplary integrated bonding wire structure <NUM> (shown in <FIG>) after trimming to design dimensions. During trimming, structural base <NUM> (shown in <FIG>) can be removed from second face <NUM> of damping material <NUM>. Additional, damping material <NUM> defines first face <NUM>, which is positioned opposite second face <NUM>. First face <NUM> is oriented parallel to grid <NUM>.

<FIG> is a perspective diagram of an exemplary integrated bonding wire structure <NUM> (shown in <FIG>), forming phased array ultrasonic transducer <NUM>. <FIG> further illustrates a transducer membrane <NUM> laminated to first face <NUM> and PCB <NUM> laminated to second face <NUM>. Beneath transducer membrane <NUM> are a plurality of ultrasonic transducers <NUM> arranged in a matrix and respectively coupled to at least one of bonding wire elements <NUM> of integrated bonding wire structure <NUM>. Likewise, PCB <NUM> includes a plurality of circuits respectively coupled to opposite ends of at least one of bonding wire elements <NUM>.

<FIG> is a perspective cross-sectional diagram of an exemplary phased array ultrasonic transducer <NUM> shown in <FIG> and <FIG> illustrates bonding wire elements <NUM> of integrated bonding wire structure <NUM> coupling transducer membrane <NUM> and PCB <NUM>.

<FIG> illustrate various shapes in which integrated bonding wire structure <NUM> may be formed. <FIG> is a cross-sectional diagram of an exemplary straight bonding wire structure <NUM>. <FIG> is a cross-sectional diagram of an exemplary straight bonding wire structure <NUM> for a curved phased array ultrasonic transducer. <FIG> is a cross-sectional diagram of an exemplary <NUM>-D shaped bonding wire structure <NUM> for a <NUM>-D phased array ultrasonic transducer. <FIG> is a cross-sectional diagram of another exemplary <NUM>-D shaped bonding wire structure <NUM> for a <NUM>-D phased array ultrasonic transducer. In additional embodiments, other <NUM>-D shaped bonding wire structures may be used.

<FIG> is a flow diagram of an exemplary method <NUM> of manufacturing phased array ultrasonic transducer <NUM> (shown in <FIG>). Method <NUM> begins at a start step <NUM>. At an additive manufacturing step <NUM>, integrated bonding wire structure <NUM> is formed using a conductive material, such as, for example, copper. Additive manufacturing step <NUM> includes sequentially depositing layers of the conductive material to build up a plurality of bonding wire elements <NUM>, or conductive columns on top of structural base <NUM>, for example. Bonding wire elements <NUM> are arranged in grid <NUM>.

At a second additive manufacturing step <NUM>, damping material <NUM> is added to integrated bonding wire structure <NUM> to surround bonding wire elements <NUM>, and interposed with bonding wire elements <NUM>. Damping material <NUM> is then cured at a curing step <NUM>, forming a solid damping mass and further forming integrated bonding wire structure <NUM>. Damping material <NUM> can be trimmed at a trimming step <NUM> to design dimensions. Trimming step <NUM>, in certain embodiments, includes removing structural base <NUM>, because each of bonding wire elements <NUM> are held in place by damping material <NUM>. Trimming step <NUM> defines first face <NUM> of damping material <NUM> and second face <NUM> of damping material <NUM>. First face <NUM> is oriented parallel to grid <NUM> in which spacing among bonding wire elements <NUM> is defined. Second face <NUM> is positioned opposite first face <NUM>, where structural base <NUM> initially existed.

At a first lamination step <NUM>, transducer membrane <NUM> is laminated to first face <NUM> of damping material <NUM>. Beneath transducer membrane <NUM> are a plurality of ultrasonic transducers <NUM> arranged in a matrix. At least one of ultrasonic transducers <NUM> is coupled to a corresponding bonding wire element of bonding wire elements <NUM>.

At a second lamination step <NUM>, PCB <NUM> is laminated to second face <NUM> of damping material <NUM>. PCB <NUM> includes a plurality of circuits for carrying AC signals to corresponding bonding wire elements, and ultimately conductively coupling to ultrasonic transducers <NUM> through integrated bonding wire structure <NUM>.

Voids between each of the plurality of ultrasonic transducers and the damping material <NUM> are filled by a filler material <NUM>. The method ends at an end step <NUM>. In various embodiments of method <NUM>, additional steps may be performed, and/or the order of the steps may vary depending upon the application.

In the embodiments of the above described phased array ultrasonic transducers, an integrated bonding wire structure is included that couples the ultrasonic transducers to a printed circuit board. The bonding wire structure is manufactured by additive manufacturing techniques, sequentially depositing layers of a conductive material to form multiple bonding wire elements on top of a structural base. A damping material is added to the bonding wire structure and cured. The damping material can be trimmed to design dimensions, including removal of the structural base for the bonding wire structure. The membrane for the ultrasonic transducers can be laminated on a first face of the damping material, and a printed circuit board is laminated to an opposite face.

Additive manufacturing processes and systems include, for example, and without limitation, vat photopolymerization, powder bed fusion, binder jetting, material jetting, sheet lamination, material extrusion, directed energy deposition and hybrid systems. These processes and systems include, for example, and without limitation, SLA - Stereolithography Apparatus, DLP - Digital Light Processing, 3SP - Scan, Spin, and Selectively Photocure, CLIP - Continuous Liquid Interface Production, SLS - Selective Laser Sintering, DMLS - Direct Metal Laser Sintering, SLM - Selective Laser Melting, EBM - Electron Beam Melting, SHS - Selective Heat Sintering, MJF - Multi-Jet Fusion, 3D Printing, Voxeljet, Polyjet, SCP - Smooth Curvatures Printing, MJM - Multi-Jet Modeling Projet, LOM - Laminated Object Manufacture, SDL - Selective Deposition Lamination, UAM - Ultrasonic Additive Manufacturing, FFF - Fused Filament Fabrication, FDM - Fused Deposition Modeling, LMD - Laser Metal Deposition, LENS - Laser Engineered Net Shaping, DMD - Direct Metal Deposition, Hybrid Systems, and combinations of these processes and systems. These processes and systems may employ, for example, and without limitation, all forms of electromagnetic radiation, heating, sintering, melting, curing, binding, consolidating, pressing, embedding, and combinations thereof.

Additive manufacturing processes and systems employ materials including, for example, and without limitation, polymers, plastics, metals, ceramics, sand, glass, waxes, fibers, biological matter, composites, and hybrids of these materials. These materials may be used in these processes and systems in a variety of forms as appropriate for a given material and the process or system, including, for example, and without limitation, as liquids, solids, powders, sheets, foils, tapes, filaments, pellets, liquids, slurries, wires, atomized, pastes, and combinations of these forms.

An exemplary technical effect of the methods, systems, and apparatus described herein can include at least one of: (a) positioning an ultrasonic damping mass between an ultrasonic transducer membrane and the PCB, (b) reducing ultrasonic energy passing through or absorbed into the PCB, (c) increasing contact density on the PCB for phased array ultrasonic transducers, (d) reducing number of PCB layers necessary for phased array ultrasonic transducers, (e) improving performance at high ultrasonic frequencies, (f) manufacturing a bonding wire structure integrated within the ultrasonic damping mass, (g) simplifying manufacture of integrated bonding wire structure through use of additive manufacturing techniques to form the bonding wire structure and the damping mass, (h) reducing manufacturing cost for phased array ultrasonic transducers through simplified additive manufacturing, (i) further reducing manufacturing cost for phased array ultrasonic transducers through reduced PCB layers, and (j) improving reliability of phased array ultrasonic transducers through reduced ultrasonic energy imparted on the PCB.

In the preceding specification and the claims, a number of terms are referenced that have the following meanings.

Here and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.

Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only.

Claim 1:
An ultrasonic transducer array for a phased array ultrasonic transducer (<NUM>;<NUM>;<NUM>;<NUM>), the ultrasonic transducer array comprising:
a bonding wire structure (<NUM>;<NUM>;<NUM>;<NUM>;<NUM>;<NUM>) comprising a plurality of bonding wire elements (<NUM>,<NUM>,<NUM>;<NUM>), each bonding wire element (<NUM>,<NUM>,<NUM>;<NUM>) consisting of a conductive column;
a damping material (<NUM>) for attenuating ultrasonic energy surrounding the bonding wire structure and interposed with the plurality of bonding wire elements (<NUM>,<NUM>,<NUM>), wherein the damping material defines a first face (<NUM>) and a second face (<NUM>) that is opposite the first face (<NUM>);
a plurality of ultrasonic transducers (<NUM>,<NUM>,<NUM>;<NUM>;<NUM>;<NUM>;<NUM>) arranged in a matrix, wherein the ultrasonic transducers are coupled to said first face (<NUM>) of the damping material (<NUM>), each of said ultrasonic transducers coupled to one of said plurality of bonding wire elements (<NUM>,<NUM>,<NUM>) through a contact (<NUM>,<NUM>,<NUM>); and
a printed circuit board (<NUM>) comprising a plurality of circuits, wherein the printed circuit board (<NUM>) is coupled to said second face (<NUM>) of the damping material (<NUM>), each said circuit coupled to a wire element of said plurality of bonding wire elements; wherein
the bonding wire structure is manufactured by additive manufacturing techniques;
a filler material (<NUM>) fills voids between each of the plurality of ultrasonic transducers (<NUM>,<NUM>,<NUM>) and the damping material (<NUM>); and
each transducer (<NUM>,<NUM>,<NUM>) has a membrane (<NUM>,<NUM>,<NUM>) for propagating ultrasonic waves, located opposite to the first face (<NUM>) of the damping material (<NUM>).