Planar linear array for ultrasound

Abstract

Examples provided herein include piezoelectric layers for ultrasonic transducers, ultrasonic transducers, methods for manufacturing transducers, and methods for manufacturing piezoelectric layers for ultrasonic transducers. In one example, the piezoelectric layer for an ultrasonic transducer includes a nonmetallic frame and a piezoelectric material. The nonmetallic frame surrounds at least two sides of the piezoelectric material and is coupled to a lens support structure having a structure such that the acoustic lens and the piezoelectric material are oriented substantially parallel to each other. The piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens.

Description

TECHNICAL FIELD

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 18 / 477,127 entitled "PLANAR LINEAR ARRAY FOR ULTRASOUND" filed on September 8, 2023, which is a continuation-in-part of U.S. Patent Application No. 18 / 158,904 entitled "PLANAR LINEAR ARRAY FOR ULTRASOUND" filed on January 24, 2023, which claims priority to U.S. Provisional Patent Application No. 63 / 368,756 entitled "PLANAR LINEAR ARRAY FOR ULTRASOUND" filed on July 18, 2022, all of which are incorporated herein by reference in their entireties for all purposes. BACKGROUND ART

[0002] In conventional ultrasound imaging systems, arrays are used as interfaces to convert electrical signals into ultrasound and to convert received ultrasound reflected from tissue structures back into electrical signals. Some arrays use fixed acoustic lenses, such as convex RTV (room-temperature-vulcanizing silicone) lenses, in the elevation direction to focus the ultrasound beam in order to improve image resolution or image slice thickness. Currently, the most common ultrasound transducers in medical imaging are ID arrays that improve image resolution by using fixed apertures with acoustic lenses in the elevation direction. Transducer elements are arranged in the form of a linear ID row or chain (a so-called linear array), and an electronic control unit can control them individually or in groups to achieve a directing effect. While elevation resolution can be improved by using controlled multi-row arrays (e.g., 1.25D or I.SD) for elevation aperture adjustment, the complex electrical interconnections between rows and columns make such arrays costly to construct during manufacturing. Furthermore, the complexity of these connections increases the likelihood of failure and can affect the lifespan of the equipment. Additionally, although elevation resolution can be improved, current multi-row arrays are typically limited to all rows having the same center frequency.

[0003] Among the arrays used in connection with ultrasonic imaging are free-field voltage sensitivity (FFVS) and high-frequency (HF) arrays, which are constructed on metal tapered support structures. Existing structures used to mount these arrays have been found to require various angled mounting configurations for the functionality and structural integrity of the arrays, resulting in increased complexity of the resulting probes. For example, mounting the array's flex circuitry on this tapered support structure at an angle of 45 degrees or slightly above or below preserves lateral space, and a vertical electrical path is formed by adding a molded insulating layer. The metal of the tapered support structure provides mechanical strength to the array structure and acts as a ground path. However, the angled nature of the structure, which provides the desired functionality as described above, makes assembly difficult. Existing ultrasonic transducers have complex 3D structures within their array stacks. Assembly of these stacks is a lengthy process involving complex tooling by highly skilled operators. [Overview of the project]

[0004] By providing a piezoelectric layer for an ultrasonic transducer, the shortcomings of the prior art can be overcome, and the advantages described below can be achieved. Various examples of piezoelectric layers are described below, and these piezoelectric layers overcome these shortcomings in any combination (unless they are contradictory), whether or not they include the further examples listed below. The piezoelectric layer includes, for example, a nonmetallic frame and a piezoelectric material, the nonmetallic frame surrounding at least two sides of the piezoelectric material, the nonmetallic frame being coupled to a lens support structure having a structure such that the acoustic lens and the piezoelectric material are oriented substantially parallel to each other, and the piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens.

[0005] By providing transducers, the shortcomings of the prior art can be overcome, and the advantages described below can be achieved. Various examples of transducers are described below, which overcome these shortcomings in any combination (unless contradictory) whether or not they include the further examples listed below. The transducer includes, for example, a planar linear array stack, the planar linear array stack includes a lens layer including an acoustic lens and a lens support structure, and a piezoelectric layer, the piezoelectric layer includes a nonmetallic frame and a piezoelectric material, the nonmetallic frame surrounds at least two sides of the piezoelectric material, the nonmetallic frame is coupled to a lens support structure having a structure such that a portion of the acoustic lens and a portion of the nonmetallic frame are oriented substantially parallel to each other, the piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens, the structure positions one or more flex circuits, and the one or more flex circuits are coupled to the structure.

[0006] By providing ultrasonic transducers, the shortcomings of the prior art can be overcome, and the advantages described below can be achieved. Various examples of ultrasonic transducers are described below, which overcome these shortcomings in any combination (unless contradictory) whether or not they include the further examples listed below. An ultrasonic transducer includes, for example, a planar linear array stack, the planar linear array stack includes a lens layer including a lens, one or more matching layers between the lens layer and the piezoelectric layer, and a piezoelectric layer, the piezoelectric layer includes a nonmetallic frame and a piezoelectric material, the nonmetallic frame surrounds at least two sides of the piezoelectric material, the nonmetallic frame is coupled to part of a lens support structure having a structure such that the acoustic lens and the nonmetallic frame are oriented substantially parallel to each other, the piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens, the structure positions one or more flex circuits, and the one or more flex circuits are coupled to the structure.

[0007] By providing a method for manufacturing a piezoelectric layer for an ultrasonic transducer, the shortcomings of the prior art can be overcome, and the advantages described below can be achieved. Various examples of the method are described below, but the method overcomes these shortcomings in any combination (unless contradictory) of the further examples listed below, with or without. The method includes, for example, dicing a piezoelectric material to form a piezoelectric material piece of a certain size, including sizing the piezoelectric material piece of a certain size to cover an area equivalent to the active surface of the acoustic lens in the ultrasonic transducer; assembling a four-sided frame from a non-metallic material; forming at least one trench on at least one of the two parallel sides of the four-sided frame; bonding the piezoelectric material of a certain size to the four-sided frame such that the four-sided frame surrounds at least two sides of the piezoelectric material of a certain size; cutting the piezoelectric material of a certain size to form one or more kerfs oriented in a consistent direction; filling the kerfs with a material that hardens over a certain period of time; and sputtering at least a certain size of piezoelectric material piece with a conductive material based on the passage of time.

[0008] By providing a method for manufacturing transducers, the shortcomings of the prior art can be overcome, and the advantages described below can be achieved. Various examples of the method are described below, and these methods overcome these shortcomings in any combination (unless they are contradictory), whether or not they include the further examples listed below. The method includes, for example, dicing a piezoelectric material to form piezoelectric material pieces of one or more sizes, including sizing one or more pieces of piezoelectric material of one or more sizes to cover at least the area of ​​the active surface of the acoustic lens of an ultrasonic transducer; assembling one or more four-sided frames from a nonmetallic material; forming at least one trench on each side of two parallel sides of each frame of the one or more four-sided frames; stretching and arranging a foil on an object including a first parallel surface; arranging one or more stencils on the top surface of the foil, each including an opening for receiving and holding each piece of the one or more pieces of one or more sizes in a set position; arranging each piece of the one or more pieces of one or more sizes using each stencil of the one or more stencils; joining each nonmetallic frame of the one or more nonmetallic frames to each piece of the one or more pieces of one or more sizes; and arranging a second object including a second parallel surface parallel to the first parallel surface on the one or more nonmetallic frames.

[0009] Further features are also realized through the apparatus and techniques described herein. Other embodiments and aspects are also described in detail herein and are also considered to be part of the claimed embodiments.

[0010] The last claim of this specification specifically identifies one or more embodiments, and claims them as examples. The purposes, features, and advantages of the foregoing and one or more embodiments will become apparent from the following detailed description, accompanied by the accompanying drawings. [Brief explanation of the drawing]

[0011] [Figure 1]This is an exploded view of an example of a planar linear array stack for ultrasonic transducers. [Figure 2] This figure shows an example of a lens layer that can be incorporated into the planar linear array stack example described herein. [Figure 3] This figure shows an example of a lens layer that can be incorporated into the planar linear array stack example described herein. [Figure 4] This figure shows an example of a piezoelectric layer that can be incorporated into the planar linear array stack example described herein. [Figure 5] This figure shows different patterns that can be formed using a laser on piezoelectric material incorporated into an example of a planar linear array stack described herein. [Figure 6] This figure shows a structure that can be incorporated into the planar linear array stack example described herein, and which serves to fix a flexible circuit within the planar linear array stack. [Figure 7] This figure shows an example of an interposer frame that can be incorporated into the planar linear array stack example described herein. [Figure 8] This figure shows a flexible circuit structure that can be incorporated into the example of a planar linear array stack described herein. [Figure 9A] This figure shows the various elements of the planar linear array stack described herein. [Figure 9B] This figure shows the various elements of the planar linear array stack described herein. [Figure 10] This figure shows the various elements of the planar linear array stack described herein. [Figure 11] This figure shows examples of interposer frame connections to traces on the surface of one or more flex circuits in some examples of planar linear arrays described herein. [Figure 12] This figure shows an example of the assembly of a flex-bending frame and several elements of a planar linear array, as described herein. [Figure 13] FIG. 2 is a diagram illustrating an exemplary assembly of a flex bending frame and several elements of a planar linear array described herein. [Figure 14] FIG. 4 is an enlarged view of a flex bending frame incorporated into an example of a planar linear array stack described herein. [Figure 15] FIG. 7 is a diagram illustrating a backing preform during assembly of an example planar linear array for a transducer disclosed herein. [Figure 16] FIG. 10 is a diagram illustrating an example of an assembled planar linear array for a transducer disclosed herein. [Figure 17] FIG. 13 is a diagram illustrating an example of a shielding element included in several examples of the planar linear array described herein. [Figure 18] FIG. 16 is an orthographic view of an example of a planar linear array stack described herein. [Figure 19] FIG. 19 is a front view of an example of a planar linear array stack described herein. [Figure 20] FIG. 22 is an illustrative example of a bending spacer that can be incorporated into several examples of the planar linear array described herein. [Figure 21] FIG. 25 is a diagram illustrating a workflow describing various aspects of several methods of manufacturing the planar linear array described herein. [Figure 22] FIG. 28 is a diagram illustrating an example technique for forming a lens utilized in a transducer including an example of the planar linear array stack described herein. [Figure 23] FIG. 31 is a diagram illustrating an example technique for forming a piezoelectric layer used in a transducer including an example of the planar linear array stack described herein. [Figure 24] FIG. 34 is a diagram illustrating a workflow describing various aspects of several methods of manufacturing a piezoelectric layer described in FIGS. 23 and 25. [Figure 25] FIG. 37 is a diagram illustrating an example of a piezoelectric layer that can be incorporated into an example of the planar linear array stack described herein. [Figure 26]FIG. 2 is a diagram showing an example of a technique for forming a plurality of piezoelectric layers used in a transducer that can include the example planar linear array stack described in the present specification. [Figure 27] FIG. 27 is a diagram showing an example of a cross-section that is part of the process shown in FIG. 26. [Figure 28] FIG. 28 is an exploded view of an example of a planar linear array stack for an ultrasonic transducer. [Figure 29] FIG. 29 is an alternative view of the planar linear array of FIG. 28. [Figure 30] FIG. 30 is an enlarged view of a planar linear array including a tapered structure. [Figure 31] FIG. 31 is a top view of an embodiment of the planar linear array of FIGS. 28 to 30. DETAILED DESCRIPTION OF EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0012] The accompanying drawings, which are not drawn to scale for ease of understanding, wherein like reference numerals may refer to identical or functionally similar elements throughout the separate views, and which are incorporated in and form a part of this specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention. As will be appreciated by those skilled in the art, the accompanying drawings are provided for ease of understanding and illustrate aspects of several embodiments of the present invention. The present invention is not limited to the embodiments shown in the drawings.

[0013] Example Terms In this specification, terms such as “connect,” “connected,” “contact,” and / or “coupled” are broadly defined to encompass a variety of divergent arrangements and assembly techniques. These arrangements and techniques include, but are not limited to, (1) direct joining of one component to another without the presence of intervening components (i.e., the components are in direct physical contact), and (2) joining of one component to another in the presence of one or more components, provided that one component that is “connected,” “contacted,” or “coupled” to the other component communicates with the other component in some form of operational communication (e.g., electrical, fluid, physical, optical, etc.) despite the presence of one or more further components in between. It should be understood that some components that are in direct physical contact with each other may or may not be in electrical and / or fluid contact with each other. Furthermore, two electrically connected, electrically coupled, optically connected, optically coupled, fluidically connected, or fluidly coupled components may or may not be in direct physical contact, and one or more other components may be present between them.

[0014] As used herein, the terms “including” and “comprising” have the same meaning.

[0015] The terms “substantially,” “approximately,” “about,” “relatively,” or other similar terms, which may be used throughout this disclosure, including the claims, are used to describe small variations from a standard or parameter resulting from variations in processing, etc. Such small variations include zero variation from the standard or parameter. For example, these variations may mean ±10% or less, such as ±5% or less, ±2% or less, ±1% or less, ±0.5% or less, ±0.2% or less, ±0.1% or less, ±0.05% or less. The terms “substantially,” “approximately,” “about,” “relatively,” or other similar terms as used herein may also mean no variation.

[0016] As used herein, "electrically coupled" means the transfer of electrical energy between any combination of power sources, electrodes, conductive surfaces, droplets, conductive traces, wires, waveguides, nanostructures, and other circuit segments. The term electrically coupled can be used in relation to direct or indirect connections and can pass through various intermediaries such as fluid intermediaries and air gaps.

[0017] As used herein, the term "kerf" refers to an adjustable gap between diced portions of an acoustic surface, which in each example can be filled with a different material (to maintain and adjust the gap).

[0018] The term "ROC" refers to the radius of curvature and is used herein in the context of acoustic design. In medical ultrasound arrays, the ROC lens is generally a cylindrical focusing lens. Lenses referred to herein as ROC lenses are single-radius focusing lenses, while lenses referred to herein as multi-ROC lenses are multi-radius focusing lenses. The ROC of a convex acoustic lens is the product of the geometric focal length and a value smaller than the result of dividing the velocity of sound in the medium by the velocity of sound in the lens material. The acoustic lenses used herein are designed based on the paraxial theory or Fresnel approximation in geometrical optics, assuming a plane wavefront emitted perpendicular to the transducer surface.

[0019] As used herein, the term "PZT" refers to a ceramic perovskite material that exhibits the piezoelectric effect, i.e., lead zirconate titanate (or lead zirconium titanate), a compound that changes shape when an electric field is applied. In this context, PZT is used in ultrasonic transducers. PZT ceramics are the most commonly used piezoelectric ceramics because they have higher sensitivity and operating temperatures than other piezoelectric ceramics. As used herein with "PZT" as "PZT / SX", the term "SX" refers to a single-crystal lead zirconate titanate or lead zirconate titanate layer.

[0020] As used herein, the term “matching layer” refers to a layer within a transducer array that facilitates the transfer of ultrasonic energy from the element to the medium. In the examples herein, the matching layer is generally located between the element and the lens (as in existing transducer arrays). The matching layer is composed of a material that facilitates energy transfer, including, but is not limited to, epoxy, elastomer, polyurethane, and polystyrene. In an ultrasonic transducer, one or more matching layers provide an acoustic impedance gradient that allows acoustic energy from the transducer to penetrate smoothly into body tissue and reflected acoustic waves (return echoes) to return smoothly to the transducer and be detected.

[0021] As used herein, the terms “signal flex” and “ground return flex” refer to signal and ground return elements in flexible electronics, also known as flex circuits, which are circuits that can conform to a desired shape (e.g., bend during use). The term “flex” refers to a flexible circuit. Flex circuits are used as connectors in a variety of applications where the serviceability of rigid circuit boards or hand wiring is limited by flexibility, space saving, and / or production constraints. Many flexible circuits are passive wiring structures used to interconnect electronic components.

[0022] As used herein, the term “stack configuration” means, in the context of the examples herein, a pile of objects referred to herein as a “stack,” which includes, in some cases, aligned and misaligned layers, and contains diced piezoelectric layer fragments arranged in multiple columns in the height direction. As described herein, each stack configuration is described in relation to three dimensions: width in the height direction, length perpendicular to the width, and stack-up thicknesses configuration perpendicular to both length and width. An example of these dimensions is shown in Figure 1 herein.

[0023] As used herein, the term “beam pattern” (which may also be called “acoustic radiation pattern”) refers to the relative sensitivity of a transducer as a function of spatial angle. This pattern is determined by factors such as the operating frequency of the vibrating surface, as well as its size, shape, and acoustic phase characteristics. The beam pattern of a transducer can be reciprocal, meaning that the beam pattern can be the same whether the transducer is used as a transmitter or a receiver. In general, transducers can be designed to radiate sound in many different types of patterns with different shapes (e.g., beam width) ranging from omnidirectional to very narrow beams.

[0024] As used herein, the term “phased array” (PA) refers to an array of ultrasonic transducers that emit individual elements on the array in a specific order to direct sound waves in a particular direction. For this purpose, a PA probe consists of many (e.g., small) ultrasonic transducers, each of which can be pulsed individually. By varying the timing through this pulsation (e.g., gradually delaying the pulses from each transducer as the line moves upward), the probe will radiate a beam pattern at a set angle based on a progressive time delay through constructive interference. By varying this progressive time delay, the beam can be electronically manipulated.

[0025] As used herein, the term "excimer laser" refers to a type of ultraviolet (UV) laser, also known as an "exciplex laser."

[0026] As used herein, the term “lens layer” means one or more elements in a planar linear array stack as described herein, which may include acoustic lenses fixed to a lens support structure. The lens support structure, or in some examples the lens layer, may include acoustic lenses that do not have a lens support structure.

[0027] As used herein, the term “piezoelectric layer” refers to a layer in a planar linear array stack that may contain piezoelectric material (e.g., PZT, PZT / SX, etc.). As will be described in more detail herein, in some examples, the piezoelectric layer may include a non-metallic frame (e.g., it may be made of ceramic) that borders (e.g., surrounds) at least two sides of the piezoelectric material. Hereinafter, this frame is referred to as a “non-metallic frame.”

[0028] As used herein, the term “interposer frame” means a non-conductive structure within a planar linear array stack that can be used to arrange conductive elements, and the examples herein may include one or more flexible circuits. The interposer frame may be made of a solid material (e.g., ceramic) coated with a conductive layer to bridge the ground and signal electrode connections within the planar linear array stack to the outside.

[0029] As used herein, the term “overmould” refers to a material that can be used to bond and position elements within a planar linear array stack. In the examples herein, overmoulds can be used to position one or more conductive elements, such as flex circuits.

[0030] As used herein, the term “flex bending frame” refers to an element of a planar linear array stack that can be used to shape the aforementioned conductive elements arranged by an interposer frame.

[0031] As used herein, the term “backing preform” refers to a backing layer within a planar linear array stack that can be used to improve transducer signal quality by absorbing and attenuating backend signals from ceramic elements (e.g., interposer frames).

[0032] As used herein, the term “bending spacer” means, in the examples herein, a spacer that can help bend a conductive element (e.g., a flexible circuit) based on its position (spacers can be used in transducers to suppress side imaging and interference).

[0033] As used herein, the term “conductive shapes of uniform scale” means shapes including, but not limited to, spheres, pyramids, and cubes. The term “uniform scale” means shapes having a uniform height (e.g., stack-up thickness). The relative orientation of height measures is described herein.

[0034] As used herein, the term "parallel lap" refers to the removal of material, including metal and oxide layers, layer by layer using chemical solutions, etching gases, or mechanical polishing. The parallel lapping process allows for the controlled removal and / or retention of specific layers.

[0035] As used herein, the term “trench” broadly refers to any impression formed in a material by the removal of a portion of the material. Thus, as used herein, a trench can be a notch, channel, hole, groove, slot, channel, corrugation, fold, crimp, or cut. Wherever material is removed to form a hole or impression, regardless of its depth, this gap may always be referred to as a trench. Furthermore, each of these listed terms is used synonymously to mean any possible impression or hole.

[0036] The term “bond,” as used herein in various forms as either a noun or a verb, means the act of attaching one item to another using a binder, and may include, but is not limited to, making such a connection using a binder such as an adhesive and / or epoxy. In some examples herein, a binder may be selected (to form a bond) based on a binder containing a material that is not modified by the use of a transducer formed using one or more processes described herein.

[0037] In this specification, the term "high frequency" in relation to transducers refers to transducers operating at ultrasound frequencies above 3–5 MHz. Conversely, "ultra-high frequency" refers to transducers operating at ultrasound frequencies above 10 MHz. The term "low frequency" refers to transducers operating at ultrasound frequencies below 3 MHz. These terms are not strictly defined, but as will be explained herein, some examples of transducers described herein can operate at frequencies ranging from low to ultra-high.

[0038] As used herein, the terms “pitch error” and “walk off” are synonymous with unintended geometric changes that occur in various layers, including piezoelectric layers, during the manufacturing process due to warping of layer dimensions caused by the use of heat in the manufacturing process. For example, the functionality of a piezoelectric layer may be related to its manufacturing process, such as the consistent spacing of trenches. In a piezoelectric layer, the sum of the gap width and the kerf width multiplied by the number of kerfs equals the end-to-end length of the piezoelectric body. Any difference between the measured mathematical number and the theoretical number is the pitch error or walk off. Some manufacturing processes involve applying heat to piezoelectric materials (e.g., PZTs), and this heat is very stressful for the PZT, which in some cases can manifest as shape changes and pitch errors or walk off. Piezoelectric layers manufactured by forming ground trenches in piezoelectric materials using lasers are particularly susceptible to pitch errors or walk off.

[0039] As used herein, the term “active surface of the acoustic lens” refers to the portion of the lens enclosed by a non-metallic frame within an opening (e.g., a central opening) in a planar linear array as described herein. The active surface of the acoustic lens is the surface covered by the piezoelectric material of the piezoelectric layer as described herein. In some literature, the active surface of a transducer refers to the piezoelectric material, and the “active surface of the acoustic lens” is defined by the location of the piezoelectric material in the transducer stack.

[0040] As used herein, the term “machined” means a general manufacturing method that includes, but is not limited to, conventional machining with an end mill, forming, casting, 3D printing, and any of the machines or tools used in any other way to form the components described below.

[0041] As mentioned above, some existing arrays used in ultrasonic transducers are built on metal tapered support structures, which are examples of the complex three-dimensional (3D) structures used in this technology. Such tapered structures provide mechanical strength to the array structure, including the retention of lateral space, and can function as grounding paths. However, the resulting 3D structures can be complex and difficult (and expensive) to assemble. Also, the need to angle the flexible circuit (e.g., 45 degrees) limits the ability to miniaturize the array, and therefore the resulting probes may not be suitable for specific applications. Furthermore, complex 3D structures make it difficult to form flat and parallel surfaces with a certain tolerance. As the footprint of the array increases, such as in ultra-high resolution transrectal ultrasound (UHR-TRUS) probes, it becomes even more difficult to maintain flatness to tight tolerances. As the footprint decreases, it becomes difficult to form tools to handle such small arrays and to assemble components into the small arrays. As will be discussed later, there is a need to reduce the 3D complexity and volume of transducer arrays, regardless of whether the array includes a tapered support structure or another existing 3D structure of similar volume. The examples described herein address this need.

[0042] This specification describes a method for manufacturing an ultrasonic transducer including a planar linear array stack, and examples of transducers including this planar linear array stack. By utilizing transducers including the planar structure examples described herein, the manufacturing process is simplified compared to existing non-planar examples, and the yield is increased without compromising acoustic quality. The planar array structure examples described herein can be incorporated into suitable ultrasonic probes such as UHR-TRUS probes or periodontal probes. Various embodiments of the examples described herein are described, but some examples may include: 1) a substantially horizontal (e.g., flat) interposer frame which can be made of a non-metallic material including, but not limited to, ceramic; 2) an electrical connection part which utilizes a shape covered with a conductive material; 3) a piezoelectric frame (also referred to herein as a layer) of non-conductive material (e.g., ceramic) used to increase mechanical strength, flatten the array to facilitate manufacturing, and provide an embedded conductive channel for grounding; 4) a backing preform which conforms to the planar structure and reduces material costs; and 5) a lens layer which includes a lens with or without a peripheral frame. The presence of a lens frame enhances mechanical strength and electrical safety isolation. Advantages of the arrays described herein and their manufacturing processes include, but are not limited to, simplification of manufacturing tools, elimination of lengthy manufacturing processes, reduced manufacturing difficulties, reduced reliance on operator skills, reduced failure rates, and decreasing reduction costs.

[0043] Figure 1 is an exploded view of an example of a planar linear array stack 100 for an ultrasonic transducer. Several embodiments are described in general terms in this figure, and these embodiments are described in more detail in the following figures. For example, Figures 2 and 3 show various embodiments of the lens layers 210 and 310 in the planar linear array stack 100 (Figure 1). Figure 4 is a top view of various embodiments of the piezoelectric layer 420 in the planar linear array stack 100 (Figure 1), and Figure 5 shows various examples of piezoelectric material that is part of the piezoelectric layer 120 (Figure 1) in the planar linear array described herein. Figure 6 shows an overmolding 632 that fixes the flex circuit 630 to the interposer frame 625. Figure 7 shows an example of the interposer frame 725. Figure 8 shows a flex circuit structure including a flex registration strip 833 and the flex circuit 830. Figures 12 and 13 show flex bending frames 1235 and 1335. Figure 15 shows a backing preform 1540. Figure 20 shows the bent spacer 2045. The contents of the remaining figures will also be described in this specification.

[0044] Referring to Figure 1, the illustrated example of the planar linear array stack 100 includes indicators of width along the longitudinal axis 101, also called the longitudinal axis 101, width axis 108, and stack-up thickness 109. In this specification, reference to the bottom of the planar linear array stack 100 means the planar linear array stack 100 starting from the lens layer 110. Reference to the top of the planar linear array stack 100 in this specification means the planar linear array stack 100 starting from the bending spacer 145. Therefore, the statement that the first element is located below the second element means that the first element is closer to the lens layer 110 than the second element. The statement that the first element is located above the second element means that the first element is closer to the bending spacer 145 than the second element.

[0045] Referring to Figure 1, the planar linear array stack 100 includes a lens layer 110. This lens layer 110 may include acoustic lenses fixed to a lens support structure, or, in some examples, the lens layer 110 may include acoustic lenses without a lens support structure. The acoustic lenses used in various examples may be concave or convex. As an example, the acoustic lenses shown in the figures of this specification are concave only.

[0046] The planar linear array stack 100 also includes a piezoelectric layer 120 of a piezoelectric material (e.g., PZT, PZT / SX, etc.). As shown in the following figure, this piezoelectric layer 120 includes a frame, which is not made of metal (e.g., can be formed of ceramic), that borders (e.g., surrounds) at least two sides of the piezoelectric material, and is referred to herein as a “non-metallic frame”. In some examples, the non-metallic frame surrounds four sides of the piezoelectric material. This frame can position the piezoelectric material centrally with respect to the longitudinal axis 101 and the width axis 108 of the planar linear array stack 100. The non-metallic frame of the piezoelectric layer 120 not only centers the piezoelectric material with respect to the width axis 108 and the longitudinal axis 101 of the planar linear array stack but also defines the elevational depth.

[0047] In some examples of the planar linear array stack 100, the nonmetallic frame of the piezoelectric layer 120 is coupled to part of the lens support structure such that the acoustic lens and the nonmetallic frame are oriented substantially parallel to each other along the axis of the stack-up thickness 109. In some examples, such as the planar linear array stack 100 in Figure 1, at least one matching layer 115 separates the lens layer 110 and the piezoelectric layer 120. The matching layer 115 can provide a material buffer from acoustic impedance between elements in the transducer, including an insulating element, and elements through which the generated signal passes. The surface of the piezoelectric material of the piezoelectric layer 120 adjacent to at least one matching layer 115 may include at least one electrode. This surface electrically couples the piezoelectric material with at least one matching layer 115. Above the piezoelectric layer 120 is an interposer frame 125 that positions one or more flex circuits 130. The interposer frame 125, which can be made of ceramic or solid material, is not conductive, but is used to lock conductive materials and / or interconnect conductive elements within the planar linear array stack 100, thereby enabling conductivity. In some examples, a conductive layer is added to the interposer frame 125 so that it can bridge ground connections and signal electrode connections within the planar linear array stack 100 (described in further detail below).

[0048] For ease of illustration, only a single flex circuit 130 is shown in Figure 1. Multiple flex circuits can be used, as illustrated in the following figures, and these flex circuits can electrically couple the interposer frame 125 to the piezoelectric layer 120. The flex circuit 130 can also be further coupled to the ground electrode. Although not shown in Figure 1, multiple shapes of uniform scale (e.g., metallic microshapes) coated with or composed entirely of conductive material can couple the interposer frame 125 to the flex circuit 130. While spheres are used throughout as an example of shapes, as those skilled in the art will understand, conductive shapes available in the various examples herein may include, but are not limited to, pyramids and cubes, provided that the height of the shape (e.g., stack-up thickness 109) is uniform (when placed). Different shapes can also be mixed.

[0049] In Figure 1, the relative position of the interposer frame 125 is below one or more flex circuits 130 (i.e., closer to the lens layer 110) and above the piezoelectric layer 120 (i.e., closer to the bending spacer 145), and the flex bending frame 135 is substantially parallel (along the stack-up thickness axis 109) to the first portion of one or more flex circuits 130. The flex circuits 130 are fixed to the interposer frame 125 by an overmolding 132. As described herein, a second portion of each flex circuit 130 is bent in the direction of the stack-up thickness 109 such that this portion of the flex circuit 130 is substantially perpendicular to the surface of the flex-bending frame 135 along the width axis 108 of the planar linear array 100 (for example, this portion of the flex circuit 130 is substantially perpendicular to a plane defined by the width axis 108 dimension and the longitudinal axis 101 dimension, and the surface of the flex-bending frame 135 is substantially parallel to this plane). Thus, the flex-bending frame 135 can be used to form one or more flex circuits 130 such that a portion of the bent flex circuit is perpendicular to the width axis 108 of the planar linear array stack 100 and bent in the direction of the stack-up thickness 109.

[0050] As shown in Figure 1, both the interposer frame 125 and the flex bending frame 135 have cavities 126 and 136. These cavities 126 and 136 align with each other when stacked in the planar linear array stack 100, forming an opening or cavity at a central position along the width axis 108 and longitudinal axis 101 of the planar linear array stack 100. Part of the backing preform 140 passes through this opening (formed by cavities 126 and 136). Above the backing preform 140, a bending spacer 145 is positioned along the stack-up thickness 109 to help bend / position one or more flex circuits 130, so that a portion of each flex circuit of the one or more flex circuits 130 is substantially parallel to the surface of the bending spacer (along the width 108), while the other portions of the one or more flex circuits 130 are bent and therefore perpendicular to the width axis 108 of the planar linear array stack (extending in the direction of the stack-up thickness 109). As described above, the backing preform 140 conforms to the planar structure and reduces material costs because the volume of the backing preform is smaller than that of other structural guides and is formed to conform to the planar structure on the planar linear array. The backing preform 140 accommodates bending spacers 146 used to guide one or more flex circuits 130.

[0051] Figures 2 and 3 show examples of lens layers 210, 310 (e.g., Figures 1 and 3) that can be incorporated into examples of planar linear array stacks described herein, including, but not limited to, the planar linear array stack 100 of Figure 1. The difference between the lens layer 210 in Figure 2 and the lens layer 310 in Figure 3 lies in the lens support structures 212, 312 used to position the acoustic lenses 211, 311 in each example.

[0052] In the lens layer 210 of Figure 2, the support structure 212 for the acoustic lens 211 includes a first bar 213a and a second bar 213b located on either side of the acoustic lens 211. The acoustic lens 211 may be made of a dielectric material, including, but not limited to, Rexolite®. The material of the support structure 212 may be selected based on having a similar coefficient of thermal expansion to that of the acoustic lens 211, minimizing warping, including arching deformation of the lens layer 210, when heated (e.g., during use of an ultrasonic transducer). For the integrity and lifespan of the planar linear array stack 100 (Figure 1) and any transducer incorporating the planar linear array stack 100 (Figure 1), it is desirable to avoid differential expansion between the acoustic lens 211 and the support structure 212. Materials for the support structure 212 include, but are not limited to, ceramics, gypsum containing ceramics, and gypsum containing metals (e.g., silver, gold).

[0053] As those skilled in the art will understand, the acoustic lens 211 can be used to focus an ultrasonic beam to improve image sensitivity. For this purpose, the acoustic lens 211 has a certain curved portion (e.g., ROC) formed in it to properly focus the ultrasonic beam. Thus, the acoustic lens 211 in Figure 2 includes a curved portion 214. The support structure 212 of the lens layer 210 positions the curved portion 214 in width axis 108 and longitudinal axis 101 coordinates similar to those of the piezoelectric material of the piezoelectric layer (e.g., 120 in Figure 1) when assembled into a planar linear array stack (e.g., 100 in Figure 1). This positioning centers the acoustic lens 211 and the piezoelectric material along the width axis 108 and longitudinal axis 101 of the planar linear array stack 100.

[0054] In the lens layer 310 of Figure 3, the support structure 312 for the acoustic lens 311 includes a frame 313 located at the periphery of the acoustic lens 311. The acoustic lens may be made of a dielectric material, including, but not limited to, Rexolite®. Similar to the support structure 212 in Figure 2, in the lens layer 310 of Figure 3, the material of this support structure 312 may be selected based on having a similar coefficient of thermal expansion to that of the acoustic lens 311, minimizing warping, including arch deformation, of the lens layer 310 when heated (during use of the ultrasonic transducer). For the integrity and lifespan of the planar linear array stack 100 (Figure 1) and any transducer incorporating the planar linear array stack 100 (Figure 1), it is desirable to avoid differences in elongation between the acoustic lens 311 and the support structure 312. Materials for the support structure 312 include, but are not limited to, ceramics, gypsum containing ceramics, and gypsum containing metals (e.g., silver, gold). As shown in Figure 3, the acoustic lens 311 may include a curved portion 314, and the portion of the support structure 312 that contacts the curved portion 314 may also include this shape. When the support structure 312 of the lens layer 310 is incorporated into a planar linear array stack (for example, Figure 1, 100), it positions the curved portion 314 of the lens at a central position along the width axis 108 (Figure 1) and longitudinal axis 101 (Figure 1) of the planar linear array stack.

[0055] Figure 4 shows an example of a piezoelectric layer 420, which is shown in Figure 1 as another example of piezoelectric layer 120. The top view shown in Figure 4 shows an example of a piezoelectric layer 420 including a non-metallic frame 421, which can be made of insulating material including, but is not limited to, ceramic. In the context of this example, the non-metallic frame 421 performs at least one of three functions: 1) centering the piezoelectric material 422 along the longitudinal axis 101 (Figure 1) and width axis 108 (Figure 1) of the planar linear array 100 (Figure 1); 2) defining the height of the planar linear array 100 (Figure 1) (e.g., Figure 1, 101); and 3) including a ground trench 423 that provides a ground connection from the front to the back of the piezoelectric layer 420 (forming part of the return signal path).

[0056] The non-metallic frame 421 surrounds the piezoelectric material 422 (e.g., PZT, PZT / SX, etc.). The piezoelectric layer 420 functions as a pure 1-3 composite used in a high-frequency transducer. To set the shape, size, and thickness of the piezoelectric material 422, the material itself can be pre-diced into sections or array elements of the desired shape, size, and thickness for the desired application. In one non-limiting example, the piezoelectric material 422 is cut to the precise size of 46.0 mm × 2.8 mm with an elevation width of 2.4 mm. The PZT is then bonded to the piezoelectric frame 421 using a binder (e.g., adhesive). This structure can be used to fabricate a pure 1-3 composite that can be used in a high-frequency transducer. The non-metallic frame 421 holds the piezoelectric material 422 in place such that the piezoelectric material 422 is centered along the width axis 108 (Figure 1) and the longitudinal axis 101 (Figure 1). The non-metallic frame 421 determines a uniform vertical width by controlling the width of the central opening based on its positioning according to the width axis 108 (Figure 1) and the longitudinal axis 101 (Figure 1) (in which the piezoelectric material 422 is positioned). For example, the non-metallic frame 421 can maintain consistency in vertical width. The non-metallic frame 421 also provides a grounding path from the piezoelectric material 422 to the flexible circuit (e.g., Figure 1, 130) via the ground trench 423. Electrical connectivity within the planar linear array will be further described in the description of Figures 9A and 9B, collectively referred to as Figure 9 in this specification.

[0057] The non-metallic frame 421 maintains the rigidity of the piezoelectric material 422 and improves the lifespan of the piezoelectric material 422, which functions as the active region of the piezoelectric layer 420. As described above, the size of the piezoelectric material 422 can be determined according to the intended use of the resulting transducer. In the example shown in Figure 4, the non-metallic frame 421 surrounds all four sides of the piezoelectric material 422, but in some examples, the non-metallic frame 421 surrounds only two sides of the piezoelectric material 422. In some examples, the non-metallic frame 421 centers the piezoelectric material 422 with respect to the width axis 108 (Figure 1) and the longitudinal axis 101 (Figure 1) of a planar linear array stack (e.g., Figure 1, 100). As with the lens layer (e.g., Figures 2, 210 and 3, 310), the element centered with respect to the width axis 108 (Figure 1) and the longitudinal axis 101 (Figure 1) by the support structure can be attached to the support structure using a binder such as an adhesive or epoxy that does not degrade during use of the resulting transducer.

[0058] The size of the piezoelectric material 422 can be determined according to the intended use of the transducer. The size of the piezoelectric material 422 can vary, and in some examples it is similar in size to the acoustic lens (e.g., Figures 2, 211 and 3, 311). The non-metallic frame 421 can be positioned such that the piezoelectric material 422 is substantially in the same position as the acoustic lens (e.g., Figures 2 and 3, 211 and 311, respectively) with respect to the width axis 108 (Figure 1) and longitudinal axis 101 (Figure 1) of the planar linear array stack, but at different coordinates on the axis representing the stack-up thickness 109 (Figure 1). Thus, in these examples, the lens layer (e.g., Figures 2, 210 and 3, 310) and the piezoelectric layer 420 are substantially parallel to each other in the planar linear array stack (e.g., Figure 1, 100).

[0059] As shown in Figure 4, the non-metallic frame 421 may include one or more ground trenches 423. To create a ground trench 423 in a non-metallic (e.g., ceramic) frame 421, as will be described later with respect to the manufacturing method of the planar linear array stack disclosed herein, in one example, a trench is drilled (e.g., by machine or milling) in the non-metallic frame 421, the trench is filled with a first conductive material metal (e.g., silver, gold), and the filled trench is covered with a second conductive material to form the ground trench 423. These conductive materials may be the same or different. For example, the ground trench can be covered with gold and filled with solver epoxy. Providing a ground trench 423 in the non-metallic frame 421 means that the ground connection of the array is simplified compared to the ground connection of existing arrays. When working with piezoelectric materials, it is generally difficult to create a signal ground because exposed electrodes are used, which may interfere with the desired planar quality of the array. In the examples herein, the non-metallic frame 421 can function as an insulator around the ground trench 423, which can be positioned coplanar with the upper surface of the piezoelectric layer 420, thereby maintaining the planar quality of the array.

[0060] Turning to the piezoelectric material 422 itself, the piezoelectric material 422 includes one or more kerfs cut into a pattern. The timing of cutting the pattern into the piezoelectric material 422 varies. In some examples, the piezoelectric material 422 is patterned before assembling the piezoelectric layer 420. In other examples, the piezoelectric material 422 is patterned after assembling the piezoelectric layer 420. Different patterns can be selected depending on the intended use of the transducer. In yet another example, the piezoelectric material 422 is patterned both before and after assembling the piezoelectric layer 420. Figure 23, later described herein, shows an embodiment of a method for forming example 2320 of the piezoelectric layer 420. In non-limiting examples, the piezoelectric layer 2320 can be incorporated into different stacks for use in different ultrasonic technologies, such as a planar linear array 100 (Figure 1).

[0061] Figure 5 shows different patterns that can be formed on the piezoelectric material 422 using a laser, including bonding the piezoelectric material 422 to the piezoelectric material 422, or bonding the piezoelectric material 422 to the non-metallic frame 421, either before or after incorporating the piezoelectric material 422 into the piezoelectric layer 420. These patterns include a first pattern 502, a second pattern 503, and a third pattern 504. Figure 5 also shows the height 505 (e.g., longitudinal axis 101, Figure 1) and thickness 506 (e.g., stack-up thickness 109, Figure 1) of the piezoelectric material in each pattern. As those skilled in the art will understand, the piezoelectric material can be patterned with a conventional sub-dice pattern, which longitudinally divides the center of the transducer element by a single sub-dice kerf cut. This sub-dice kerf cut has the same length as the transducer element. As those skilled in the art will understand, the width / height ratio of the transducer elements should be less than or equal to the "golden ratio" of approximately 0.6 to minimize the lateral vibrational modes of the PZT. As shown in Figure 5, each pattern includes a main kerf 507, which is the aforementioned sub-diced kerf that subdivides the dielectric (e.g., piezoelectric) material. The main kerf 507 can be cut between each element at this pitch. Sub-diced kerfs are cut in the center of each element. In addition to the main kerf 507, a second pattern 503 also includes a square pattern, and a third pattern 504 also includes a parallelogram pattern. These patterns can be used, for example, in arrays with a 90-micron pitch. In some examples, but not limited to, lasers including excimer lasers can be used to machine the piezoelectric material 422 to form these kerfs. For example, a laser can cut 8-10 micron kerfs to a depth of ~100 microns in piezoelectric materials such as PZT ceramics, forming kerfs of approximately 3-5 microns in piezoelectric material 422. This measurement is for illustrative purposes only and does not imply limitations.In some cases, a back-cut is also performed using a laser to maintain uniformity in calf width along the vertical structure.

[0062] As shown in Figure 1, the planar linear array stack 100 may include an interposer frame 125 for positioning one or more flex circuits 130. Figure 6 shows a structure 600 that serves to fix the flex circuits within the planar linear array stack. The structure 600 shown in Figure 6 as an exploded view includes the interposer frame 625 (e.g., Figure 1, 125) described above, the flex circuits 630 (e.g., Figure 1, 130) described above, and an overmolding 632 that fixes the flex circuits 630 to the interposer frame 625. In some examples, the overmolding 632 may include electrodes on its surface, and these electrodes may include conductive materials such as metals (e.g., gold, silver). The electrodes may be channels, but are not limited to, gold channels. For example, the overmolding may include gold foil. The flex circuits 630 may include traces (not shown in Figure 6) of conductive material (e.g., copper (Cu), gold, and / or silver, etc.) on several surfaces. Figure 6 does not include the flex alignment strip, which will be discussed later, but in this example of Figure 6, the interposer frame 625 is positioned below one or more flex circuits 630, and the overmolding 632 helps to secure one or more flex circuits 630 to the interposer frame 625.

[0063] Figures 7 and 8 provide further insight into the embodiment of Figure 6. Since the interposer frame 625 is slightly obscured in Figure 6, Figure 7 shows only the interposer frame 725 itself for easier understanding. Figure 8, on the other hand, shows a flexible circuit structure 800 including a flexible alignment strip 833 and flexible circuits 830. In various examples of the planar linear arrays described herein, the flexible alignment strip 833 is positioned substantially parallel to a portion of one or more flexible circuits 830 between the interposer frame 625 and the flexible bending frame 135 (e.g., Figure 1). As shown in Figure 8, in some embodiments of the planar linear arrays described herein, each flexible alignment strip 833 joins four flexible circuits 830. The flexible alignment strip 833 provides the array elements with precise alignment (e.g., linear alignment) with a 90-micron pitch.

[0064] Figures 9 and 10 are alternative diagrams (compared to Figure 1) of various elements of the planar linear array stack described herein. These figures are provided before describing structures used to transmit electrical signals from the surface of the interposer frame 625 (Figure 6) to traces on the surface of one or more flex circuits 630 (Figure 6), uniform-scale conductive shapes 950, 1050 (Figures 9, 10) in some embodiments. Figure 9B shows a further diagram of the electrical connection of ground from the piezoelectric material to one or more flex circuits 930. Also, Figure 9A shows one or more flex circuits 930 before bending, and Figure 9B shows one or more flex circuits 930 after bending. In this specification, the uniform-scale conductive shapes (950, 1050 (Figures 9, 10)) are shown as spheres, but these shapes may also include pyramids, cubes, etc., so spheres are provided as non-limiting examples. In a planar linear array stack, the shape including the conductive shape of uniform scale can be uniform or mixed, and can have a uniform height along the stack-up depth 10⁹ axis (Figure 1).

[0065] As shown in Figures 9 and 10, the array, starting from the bottom surface of a portion of the planar linear array 900, 1000 and proceeding upward (for example, along the stack-up thickness axis from lens layer 110 to bending spacer 145, Figure 1), includes lens layers 910, 1010, which include an acoustic lens 911 having a curved portion 914. One or more matching layers 915, 1015 are present above the upper surface of the lens layers 910, 1010. Lens bonding glue 934, 1034 bonds the upper surface of lens layer 910 to the piezoelectric layer 920, or the matching layer 1015 to the piezoelectric layer 1020. The piezoelectric layers 920, 1020 include piezoelectric material 922, 1022 having electrodes on both sides, non-metallic frames 921, 1021, and ground trenches 923, 1023. The flexible circuits 930 and 1030 are connected to the ground electrode 947 after being bent. This connection is further illustrated and described in detail in Figure 9B.

[0066] Interposer frames 925, 1025 containing conductive electrodes and / or traces (e.g., gold, copper, silver) are positioned on the horizontal plane above the piezoelectric layers 920, 1020 (relative to the stack-up thickness 109 in Figure 1). Figures 9A and 10 show the flex circuits 930, 1030 before bending, so that each flex circuit 930, 1030 as a whole is parallel to the piezoelectric layer 920 (i.e., the coordinates along the stack-up thickness axis 109 are different, but the coordinates with respect to the width axis 108 and longitudinal axis 101 in Figure 1 are common). Figure 9B shows the flex circuit 930 after bending. In this example, the interposer frames 925, 1025 contain conductive electrodes and / or traces (e.g., gold, copper, silver). Overmoldes 932, 1032 are present on the surface including the top surface of the interposer frame 925. The overmoldes contain electrodes (e.g., gold) on their top surface. As shown in Figure 10, the overmolded structure 1032 includes separation ridges 1051 and trenches 1052 below the separation ridges 1051. These trenches 1052 are coated with a conductive material, but not limited to gold.

[0067] The interposer frames 925, 1025 are electrically coupled to one or more flexible circuits 930, 1030 via one or more uniform-scale conductive shapes 950, 1050 coated with a conductive material (e.g., gold, silver, etc.). In this non-limiting example, the surfaces of the interposer frames 925, 1025 are in contact with the uniform-scale conductive shapes 950, 1050 and include one or more conductive traces. The uniform-scale conductive shapes 950, 1050 transmit electrical signals from the surfaces of the interposer frames 925, 1025 in contact with the uniform-scale conductive shapes 950, 1050 to the traces on the surfaces of the one or more flexible circuits 930, 1030 in contact with the uniform-scale conductive shapes 950, 1050. Each shape is made of a dielectric material and can be uniformly coated with a conductive material. When the array is oriented as in the example in Figure 9, the uniform-scale conductive shapes 950 form vertical electrical connections.

[0068] Figure 9B shows various elements of the planar linear array 900, but focuses on the electrical connection of the ground from the piezoelectric layer 920 to one or more flexes 930 (shown as connection 947 in Figure 9A). Figure 9B shows an example of a portion of the planar linear array 900 with one or more bends 930 bent into its final configuration (for simplicity, Figure 9B shows a single bend representing one or more bends). Figure 9B also includes diagrams of the insulating and conductive portions of the planar linear array 900. In Figure 9B, the electrical path 941 shows connection 947 (e.g., Figure 9A).

[0069] The electrical path 941 is a grounding path that forms a return signal path. The electrical path 941 shows the grounding and its path in the ground trench 923 on the piezoelectric layer 920 via the ground plane 939 of one or more flex 930 and the conductive layer 943 on the interposer frame 925 (as described above, the interposer frame 925 includes conductive electrodes and / or traces (e.g., gold, copper, silver) as a conductive layer). The grounding path, the electrical path 941 proceeds from the ground trench 923 on the piezoelectric layer 920 to the nonmetal frame 921 and proceeds to one or more flex 930 via the conductive electrodes on the interposer frame 925. The ground trench 923 includes a conductive material, but is not limited to epoxy. In this example, the interposer frame 925 includes an electrical insulating material 946, but is not limited to epoxy, and a conductive material 949, which may also be epoxy. The conductive material 949 may be adjacent to the electrical path 941, and the electrical insulating material 946 bridges a portion of the conductive layer 943 on the interposer frame 925 with the conductive material 949. Connections between the conductive layer 943 on the interposer frame (which may include copper fingers 931) and one or more bent portions 930 can be bridged by a conductive shape 950 of uniform scale.

[0070] Figure 11 shows a more detailed example of the connection points 1100 of the interposer frames 925, 1025 to traces on the surface of one or more flex circuits 930, 1030 (these traces are shown as ground surfaces 939 in Figure 9B). Uniform-scale conductive shapes 1150 are doped with bonding adhesive and placed between the interposer frame and the flex circuit. Specifically, the uniform-scale conductive shapes 1150 electrically connect traces (e.g., Cu fingers) 1137 on each flex circuit (not shown in Figure 11) to traces (e.g., gold traces) on the interposer frame 1125. In this example, each shape 1150 is made of a dielectric material (e.g., glass, polymer) and uniformly coated with a conductive material (e.g., copper, gold, silver, titanium, etc.).

[0071] Figures 12–14 show examples of the flex bending frame 135 (Figure 1). Figure 12 shows the flex bending frame 1235 assembled with specific elements of the planar linear array described herein, and Figure 13 shows these parts of the planar linear array after the flex circuit 1330 has been bent using the flex bending frame 1335. Figure 14 is a magnified view of the flex bending frame 1435. The flex bending frames 1235, 1335, and 1435 can be mounted on top of the flex circuits 1230, 1330, and 1430. The flex bending frames 1235, 1335, and 1435 provide a consistent and reliable guide for bending the flex circuits 1230, 1330, and 1430, securing these connections. Figures 12 to 14 illustrate the orientation of the flex bending frames 1235, 1335, and 1435 within the array (e.g., Figures 1, 100), showing elements described in other figures, such as the lens layers 1210, 1310, and 1410, the overmoldes 1232, 1332, and 1432, the interposer frames 1225, 1325, and 1425, and the flex alignment strips 1233, 1333, and 1433. Generally, the flex bending frames 1235, 1335, and 1435 guide the flex circuits 1230, 1330, and 1430 when they are bent.

[0072] Figures 15 and 16 (1540, 1640) further illustrate the backing preform 140 and its orientation with respect to the planar linear array for transducers disclosed herein. Figure 15 shows the backing preform 1540 during assembly of an example of a planar linear array for transducers disclosed herein, and Figure 16 shows an assembled view of the example of a planar linear array for transducers disclosed herein, showing the relative orientation of the backing preform 1640. Figures 15 and 16 also show, as part of the example of the planar linear array shown in both figures, the lens layers 1510, 1610, the interposer frame utilizing the flex alignment strip 1533 (to which one or more flex circuits 1530, 1630 are mounted), and the overmoldes 1532, 1632 described herein. The number of flex circuits 1530, 1630 in Figures 15 and 16 is shown as an example only, as with all figures. The number of flex circuits 1530, 1630 and the number of flex circuits 1530, 1630 attached to each flex alignment strip 1533, 1633 can vary. In Figure 16, the flex circuits 1630 have not yet been bent using the flex bending frames 1535, 1635. For clarity, Figure 16 includes a piezoelectric layer 1620 oriented above the lens layer 1610 to illustrate the elements of the example planar linear array described herein and their relative positions to one another.

[0073] In some embodiments of the present invention, a machine or individual deposits a layer of conductive material onto the backing preforms 1540, 1640 to suppress electromagnetic interference (EMI). For example, the backing preforms 1540, 1640 can be wrapped with conductive tape, including but not limited to copper tape, to form an EMI shielding element that bridges the return signal to ground. Alternatively, in some embodiments, layers of conductive material can be deposited on the surface of the backing preforms and on the bending frame. Figure 17 shows an example of a shielding element 1742 added to an example of a planar linear array described herein. In this example, the shielding element 1742 is a conductive coating (e.g., copper) deposited on the top surface of the backing preform 1740 and the flex-bending frame 1735.

[0074] In some embodiments, a bending spacer 145 (Figure 1) is included as another element of the planar linear array described herein. The bending spacer 145 assists an individual or machine assembling the planar linear array for transducers in bending and / or positioning one or more flex circuits 130 (Figure 1). The individual or machine positions the bending spacer 145 (Figure 1) above the backing preform 140 (Figure 1) so that when one or more flex circuits 130 (Figure 1) are bent, one or more flex circuits 130 are substantially parallel to the stack-up thickness axis 109. Referring again to Figure 9B, when one or more flex circuits 930 are bent, a first portion of each of the one or more flex circuits 930 remains parallel to the piezoelectric layer along the longitudinal axis 101 (Figure 1), while a second portion of the one or more flex circuits 930 is bent perpendicular to the piezoelectric layer along the longitudinal axis 101 (Figure 1). The portion parallel to the piezoelectric layer along the longitudinal axis 101 (Figure 1) includes copper fingers 931.

[0075] Figures 18 and 19 show examples of planar linear array stacks 1800, 1900 including bending spacers 1845, 1945 from two different viewpoints. Figure 18 is an orthographic projection of the planar linear array stack 1800, and Figure 19 is a front view of the planar linear array stack 1900. As shown in both figures, the planar linear array stacks 1800, 1900 include lens layers 1810, 1910, on which piezoelectric layers 1820, 1920 are stacked. As described above, in some embodiments of the planar linear array stacks 1800, 1900, one or more matching layers separate the lens layers 1810, 1910 and the piezoelectric layers 1820, 1920. Although not shown, as described above, the lens layers 1810, 1910 may include both the acoustic lenses themselves and the lens support structures. Similarly, the piezoelectric layers 1820, 1920 may include a piezoelectric material and a support or frame structure that positions the piezoelectric material on a plane parallel to the longitudinal axis 101 (Figure 1) and the width axis 108 (Figure 1) in substantially the same orientation as the acoustic lens. The piezoelectric layers 1820, 1920 may include ground trenches. The interposer frames 1825, 1925, overmoldes 1832, 1932, and flex alignment strips 1833, 1933 work together to secure the flex circuits 1830, 1930. The flex bending frames 1835, 1935 and backing preforms 1540, 1640 guide the bending of the flex circuits 1830, 1930, and the bending spacers 1845, 1945 play a role in holding the flex circuits 1830, 1930 in place after they have been bent. The flex circuits 1830 and 1930 are bent such that a portion of each flex circuit 1830 and 1930 is substantially perpendicular to the width axis 108 (Figure 1), and another portion is substantially parallel to the width axis 108 (Figure 1). The bent spacers 1845 and 1945 are adjacent to and roughly surround portions of the top surfaces 1861 and 1961 and at least two side surfaces 1862 and 1962 of the backing preforms 1540 and 1640. Figure 20 shows an example of the bent spacer 2045 alone so that the shape of the bent spacer 2045 can be understood even outside the context of a planar linear array.

[0076] Figures 1 to 20 show various aspects of several embodiments of a planar linear array that can be incorporated into an ultrasonic transducer. Figure 21 shows a workflow 2100 illustrating various aspects of several manufacturing methods of the planar linear arrays shown in Figures 1 to 20 and 22 and described herein. The steps of the process described in workflow 2100 can be achieved by human and / or automated processes utilizing various machines and manufacturing techniques. The steps provided are examples of aspects in several embodiments of the present invention, and in some examples one or more embodiments may be combined, omitted, and / or added. To manufacture a planar linear array stack for an ultrasonic transducer as described in Figures 1 to 20, a piezoelectric layer is formed including a nonmetallic frame and piezoelectric material (2110). To manufacture several embodiments, at least two sides of the piezoelectric material are surrounded with a nonmetallic material to form the piezoelectric layer. The nonmetallic material can be fixed to a portion of the periphery of the piezoelectric material. In some embodiments, to form a piezoelectric layer, one or more gland trenches are formed in a nonmetallic material, one or more gland trenches are filled with a first conductive material (e.g., silver, gold), and one or more gland trenches are covered with a second conductive material (e.g., silver, gold). The first and second materials may be the same or different materials. In some embodiments of a planar linear array, one or more electrodes are formed on the surface of the piezoelectric material.

[0077] Continuing workflow 2100, a lens support structure is formed (2120). The formed device aligns the lens to the center position in the stack, but the lens formation workflow is described below. The lens support device is also called a lens support structure (see Figures 2, 212 and 3, 312). The method of forming the structure varies depending on the structure of the lens support device (also called a lens support structure), which may be ceramic. In some examples, a lens support structure as shown in Figure 2 includes a first bar 213a and a second bar 213b, and thus forming the lens support structure involves oriented the first bar and the second bar so that they are located on both sides of the lens 211. In some examples, such as in Figure 3, the lens support structure (lens support structure 312) is a frame, and forming the lens support structure involves oriented the frame along the periphery of the lens 314. In some examples, lenses of the planar linear array are added after all aspects of the planar linear array (illustrated in Figures 1, 18, and 19), excluding the bending spacers, have been formed or arranged. Therefore, although this workflow 2100 includes forming the lens support device, it is not necessarily required to form the lens, as the lens can be formed at a different point in the manufacturing process.

[0078] In some cases, the piezoelectric material can be machined (e.g., laser-cut) to include one or more kerfs (see Figure 5) before forming the piezoelectric layer. Thus, one or more kerfs can be formed in the piezoelectric material using, for example, an excimer laser before forming the piezoelectric layer (2110). The kerf patterns that can be formed can vary and are not limited to the following, but include cutting at least one kerf into the piezoelectric material that subdivides the piezoelectric material while maintaining the aspect ratio, and / or cutting square patterns and / or parallelogram patterns. Examples of these patterns are shown in Figure 5.

[0079] Continuing workflow 2100 with reference to Figure 21 again, one or more matching layers are formed between the lens layer and the piezoelectric layer (2140). The non-metallic material of the piezoelectric layer is bonded to the interposer frame (e.g., Figures 6, 625, 7, 725) (2150). The interposer frame (including the opening as the frame) is electrically coupled to one or more flex circuits (see Figure 8) (2160). These flex circuits include traces. In some examples, overmolding and / or flex alignment strips (see Figures 6-8) are used to secure the flex circuits to the interposer frame. The interposer frame is electrically coupled to the traces by orienting multiple uniform-scale conductive shapes on the surface of the interposer frame so that uniform-scale conductive shapes contact the traces and the interposer frame (2170). In some examples, as shown in Figure 11, the uniform-scale conductive shapes 1150 can be doped with a bonding adhesive and oriented between the interposer frame and the flex circuit to electrically connect the traces (e.g., Cu fingers) 1137 on each flex circuit to the traces (e.g., gold traces) on the interposer frame 1125. As described above, in this example, each conductive shape of the uniform-scale conductive shape 1150 is composed of a dielectric material (e.g., glass, polymer) and uniformly coated with a conductive material (e.g., copper, gold, silver, titanium, etc.).

[0080] Once the flex is fixed to the interposer frame and electrical connections are established via a uniformly scaled conductive shape, the flex-bending frame (with openings) is oriented substantially parallel to the first portion of one or more flex circuits, such that the second portion of each flex circuit extends beyond the outer boundary of the interposer frame. The second portion is bent near this outer boundary (2180). Figures 12–14 include examples of flex-bending frames 1235, 1345, and 1435, and their orientation within a planar linear stack during stack assembly. The bending of the flex circuits is also guided by bending spacers. To enable bending, the backing preform is oriented so that the bending spacers pass through the openings in the interposer frame and the flex-bending frame (see, for example, Figures 14–16) (2190).

[0081] As described above, the lens can be formed at different points in the workflow 2100. Alternatively, the lens can be formed within the lens support structure. Specifically, once the array is complete up to the stage where the flex circuit is attached, and the array is backed and the structure (e.g., backing preform) is fixed, the lens can be inserted into the lens support structure and the curved portion can be formed on the lens by rotating a rod and performing parallel rubbing on the lens surface to a certain depth. Alternatively, the lens can be added when the lens layer is added to the stack, but the curved portion will be formed at a later point after the backing preform is attached. Therefore, the curved portion can be added and / or mounted on the lens (2192) when the preform is attached.

[0082] Figure 22 shows an example of a technique for forming a lens used in a transducer, including an example of a planar linear array stack described herein. The resulting transducer focuses an ultrasonic beam to a certain depth in the imaging field. The curvature of lens 2216 provides this focus. To form the curvature of the lens, in this non-limiting example, a portion of a planar linear array stack 2200 is assembled, including a lens layer which is the acoustic lens 2211 alone, an interposer frame 2225, one or more flexes 2230, a flex bending frame 2235, and a backing preform 2240. The assembly of the planar linear array stack 2200 is completed by attaching one or more flexes 2230 and backing the structure with the backing preform 2240 (e.g., Figures 21, 2110, -2910). The planar linear array 2200 is placed within the fixture, and the acoustic lens 2211 is oriented upward (this orientation is the reverse of the vertical orientation of this element compared to Figure 1). By rotating the rod and performing parallel rubbing on the exposed upper surface 2217 to a certain depth, a curved portion 2216 is formed on the acoustic lens 2211.

[0083] Referring again to Figure 21, to further enable bending and support the flex circuit when it reaches the bent position, bend spacers (e.g., bend spacer 145 in Figure 1, bend spacer 1945 in Figure 19, and bend spacer 2045 in Figure 20) are oriented above the top surface of the backing preform and on parts of the two sides of the backing preform parallel to the top surface of the backing preform (2194). The flex is bent around the outer boundary of the flex bending frame and the bend spacers (2195). The resulting planar linear array can be placed in a housing for use in an ultrasonic probe.

[0084] The advantages of the linear planar arrays described herein and the manufacturing processes for these arrays include, but are not limited to, simplification of manufacturing tools, elimination of long manufacturing processes, reduction of manufacturing difficulties, reduced dependence on operator skills, reduced failure rates, and reduced costs. When incorporated into ultrasonic transducers, the arrays described herein offer the above advantages, excluding yield, and thus provide substantially the same and / or improved suitability, shape, and function compared to existing systems.

[0085] Embodiments of the present invention include an ultrasonic transducer, and methods for manufacturing and using the ultrasonic transducer. In some examples, the ultrasonic transducer includes a planar linear array stack. The planar linear array stack may include a lens layer including an acoustic lens and a lens support structure. A portion of the acoustic lens is fixed to the lens support structure. The planar linear array stack may also include a piezoelectric layer including a nonmetallic frame and a piezoelectric material, the nonmetallic frame surrounding at least two sides of the piezoelectric material, and the nonmetallic frame being coupled to a portion of the lens support structure such that the acoustic lens and the nonmetallic frame are oriented substantially parallel to each other. The ultrasonic transducer may also include an interposer frame for arranging one or more flex circuits, the interposer frame being coupled to the nonmetallic frame via conductive elements within the nonmetallic frame and also to one or more flex circuits. The ultrasonic transducer also includes one or more flex circuits.

[0086] In some examples of ultrasonic transducers, one or more flexible circuits and interposer frames are electrically coupled to the ground electrode.

[0087] In some examples of ultrasonic transducers, the lens support structure includes a first bar and a second bar. The first bar and the second bar are located on either side of the acoustic lens.

[0088] In some examples of ultrasonic transducers, the lens support structure includes a frame that surrounds the rectangular periphery of the acoustic lens.

[0089] In some examples of ultrasonic transducers, the lens support structure includes ceramic.

[0090] In some examples of ultrasonic transducers, the acoustic lens includes a curved portion having a minimum value on a line parallel to the piezoelectric material in a planar linear array stack.

[0091] In some examples of ultrasonic transducers, the acoustic lens contains a dielectric material.

[0092] In some examples of ultrasonic transducers, the piezoelectric material includes one or more kerfs, and the kerfs include patterns.

[0093] In some examples of ultrasonic transducers, one or more kerfs include lines that subdivide the dielectric material to maintain the aspect ratio.

[0094] In some examples of ultrasonic transducers, the pattern is selected from a group consisting of square patterns and parallelogram patterns.

[0095] In some examples of ultrasonic transducers, the non-metallic frame includes one or more ground trenches.

[0096] In some examples of ultrasonic transducers, at least one of one or more ground trenches is filled with a first conductive material and, based on that filling, covered with a second conductive material.

[0097] In some examples of ultrasonic transducers, a non-metallic frame surrounding the piezoelectric material is bonded to the outer boundary of the piezoelectric material with adhesive.

[0098] In some examples of ultrasonic transducers, the ultrasonic transducer includes one or more matching layers between the lens layer and the piezoelectric layer.

[0099] In some examples of ultrasonic transducers, the piezoelectric layer includes electrodes on a surface adjacent to one or more matching layers.

[0100] In some examples of ultrasonic transducers, the interposer frame is electrically coupled to one or more flexible circuits via a plurality of uniform-scale conductive shapes covered with a conductive material.

[0101] In some examples of ultrasonic transducers, multiple uniform-scale conductive shapes transmit electrical signals from the surface of an interposer frame in contact with the multiple uniform-scale conductive shapes to traces on the surface of one or more flexible circuits in contact with the multiple uniform-scale conductive shapes.

[0102] In some examples of ultrasonic transducers, each conductive shape of multiple uniform-scale conductive shapes is composed of a dielectric material.

[0103] In some examples of ultrasonic transducers, each conductive shape of multiple uniform-scale conductive shapes is covered with a conductive material.

[0104] In some examples of ultrasonic transducers, the surface of the interposer frame, which is in contact with multiple uniform-scale conductive shapes, includes one or more conductive traces.

[0105] In some examples of ultrasonic transducers, electrical connections via multiple uniform-scale conductive shapes coated with conductive material form perpendicular electrical connections between one or more conductive traces oriented on a plane parallel to the interposer frame.

[0106] In some examples of ultrasonic transducers, the ultrasonic transducer includes a frame positioned substantially parallel to the first portion of one or more flexible circuits, such that the second portion of each flexible circuit of one or more flexible circuits is bent substantially perpendicular to the surface of the frame perpendicular to the planar linear array stack, and the frame and lens layer lie on a parallel horizontal plane.

[0107] In some examples of ultrasonic transducers, the ultrasonic transducer includes one or more flexible alignment strips. Each flexible alignment strip is positioned between the interposer frame and a frame that is substantially parallel to the first portion of one or more flexible circuits.

[0108] In some examples of ultrasonic transducers, each of the one or more flex circuits is attached to one of the one or more flex alignment strips.

[0109] In some examples of ultrasonic transducers, a frame positioned substantially parallel to a first portion of one or more flexible circuits includes a first cavity, and an interposer frame includes a second cavity. In this example, the ultrasonic transducer also includes a backing preform that contacts the portion of one or more flexible circuits and penetrates the first and second cavities.

[0110] In some examples of ultrasonic transducers, the backing preform is covered with conductive tape.

[0111] In some examples of ultrasonic transducers, the transducer includes a bending spacer. The bending spacer is positioned above the backing preform such that the second portion of each flex circuit of one or more flex circuits is substantially parallel to the surface of the bending spacer, which is perpendicular to the planar linear array stack.

[0112] In some examples of ultrasonic transducers, a non-metallic frame positions the piezoelectric material centrally relative to the height and width of the planar linear array stack.

[0113] In some examples of ultrasonic transducers, the transducer includes an overmolding that secures one or more flexible circuits to the interposer frame.

[0114] In some examples of ultrasonic transducers, the overmolding includes electrodes on at least one surface.

[0115] In some examples of ultrasonic transducers, the ultrasonic transducer includes a planar linear array stack, the planar linear array stack includes a lens layer containing lenses, one or more matching layers between the lens layer and the piezoelectric layer, and a piezoelectric layer containing a nonmetallic frame and piezoelectric material, the nonmetallic frame surrounding at least two sides of the piezoelectric material. The transducer may also include an interposer frame on which one or more flex circuits are arranged. The interposer frame is coupled to the nonmetallic frame via conductive elements within the nonmetallic frame and is also coupled to one or more flex circuits. The transducer also includes one or more flex circuits.

[0116] In some examples of ultrasonic transducers, the ultrasonic transducer includes a planar linear array stack, the planar linear array stack includes a lens layer containing lenses and a piezoelectric layer containing a nonmetallic frame and piezoelectric material, the nonmetallic frame being coupled to a portion of the lens layer by surrounding at least two sides of the piezoelectric material. The transducer may also include an interposer frame on which one or more flex circuits are arranged, the interposer frame being coupled to the nonmetallic frame via conductive elements within the nonmetallic frame and also to one or more flex circuits. The transducer may also include one or more flex circuits.

[0117] In some examples of methods for manufacturing a planar linear array stack for ultrasonic transducers, the method includes forming a piezoelectric layer comprising a nonmetallic material and a piezoelectric material, wherein forming includes surrounding at least two sides of the piezoelectric material with the nonmetallic material. The method may also include forming a lens support structure, which orients the acoustic lens to a central position with respect to the width and height of the planar linear array stack. The method may also include coupling the lens support structure to the piezoelectric layer such that the lens support structure and the piezoelectric layer are parallel with respect to width and height.

[0118] In some examples of the method, the lens support structure includes a first bar and a second bar, and forming the lens support structure involves oriented the first bar and the second bar so that they are located on either side of the lens.

[0119] In some examples of the method, the lens support structure includes a frame, and forming the lens support structure involves oriented the frame along the periphery of the lens.

[0120] In some examples of the method, the lens support structure includes ceramic.

[0121] In some examples of the method, the method includes forming one or more kerfs on a piezoelectric material.

[0122] In some examples of the method, forming one or more kerfs involves cutting at least one kerf into the piezoelectric material to subdivide the piezoelectric material in order to maintain the aspect ratio.

[0123] In some examples of the method, forming one or more calves involves cutting a calf pattern into a piezoelectric material.

[0124] In some examples of the method, the pattern is selected from a group consisting of square patterns and parallelogram patterns.

[0125] In some examples of the method, the method involves forming one or more ground trenches in a nonmetallic material.

[0126] In some examples of the method, the method includes filling one or more gland trenches with a first conductive material. The method may also include covering one or more gland trenches with a second conductive material.

[0127] In some examples of the method, forming a piezoelectric layer further includes fixing a non-metallic material to a portion of the periphery of the piezoelectric material.

[0128] In some examples of the method, the method includes forming one or more matching layers between the lens layer and the piezoelectric layer.

[0129] In some examples of the method, forming a piezoelectric layer further includes forming one or more electrodes on the surface of a piezoelectric material.

[0130] In some examples of the method, the method involves bonding a non-metallic material of the piezoelectric layer to an interposer frame.

[0131] In some examples of the method, the method comprises electrically coupling an interposer frame to one or more flexible circuits, each surface of the one or more flexible circuits comprising a trace, the interposer frame comprising a first opening, and the electrical coupling comprises fixing the one or more flexible circuits to the interposer frame with an overmolde, the surface of which comprises one or more electrodes.

[0132] In some examples of the method, the electrical coupling involves oriented multiple uniform-scale conductive shapes on the surface of the interposer frame. The method may also include electrically coupling the interposer frame to the traces by coupling the traces to the multiple uniform-scale conductive shapes.

[0133] In some examples of the method, each conductive shape of a plurality of uniform scales includes a dielectric material coated with a conductive material.

[0134] In some examples of the method, the method involves oriented a flex-bending frame substantially parallel to a first portion of one or more flex circuits such that a second portion of each flex circuit extends beyond the outer boundary of the interposer frame, and the flex-bending frame includes a second opening.

[0135] In some examples of the method, electrically coupling an interposer frame to one or more flexible circuits further includes attaching each of the one or more flexible circuits to one of a plurality of alignment strips, and oriented each of the plurality of flexible alignment strips to be positioned between the interposer frame and the bending frame.

[0136] In some examples of the method, the method includes oriented a backing preform, which contacts one or more portions of a given flex based on penetrating a first opening and a second opening.

[0137] In some examples of the method, the method involves forming a lens within a lens support structure.

[0138] In some examples of the method, the method includes bending a second portion of each of one or more flex circuits so that the second portion of each flex circuit is oriented substantially perpendicular to the surface of the flex bending frame.

[0139] In some examples of the method, the method involves oriented the spacer above the top surface of the backing preform, on portions of two sides of the backing preform, where the two sides of the backing preform are parallel to the top surface of the backing preform.

[0140] In some examples of the method, the method involves depositing a copper shield on the upper surface of the backing preform.

[0141] In some examples of the method, the method involves using a non-metallic material to position a piezoelectric material at a central position relative to the height and width of a planar linear array stack.

[0142] Figures 23 and 24 show various top-view aspects of non-limiting methods 2300, 2400 for forming the piezoelectric layer 2320 (e.g., 420 in Figure 4). Figure 23 shows the gradual change of the piezoelectric layer 2320 itself throughout the manufacturing process, and Figure 24 shows a workflow illustrating various aspects of several methods for forming the piezoelectric layer 2320.

[0143] Referring to Figure 23, the piezoelectric layer 2320 includes, at the end of its formation, a non-metallic frame 2321, also referred to herein as a piezoelectric frame, which may be composed of an insulating material including, but not limited to, ceramics. The reason the non-metallic frame 2321 can be called a piezoelectric frame is that it is positioned surrounding the piezoelectric material 2322 in the transducer stack. The term piezoelectric frame does not mean the material that constitutes the frame. Rather, the non-metallic frame 2321 or piezoelectric frame is formed from a material including, but not limited to, ceramics, and the material of the non-metallic frame 2321 (or piezoelectric frame) is selected for its hardness, high melting point, low thermal expansion, and / or good chemical resistance.

[0144] The non-metallic frame 2321 surrounds the piezoelectric material 2322 (e.g., PZT, PZT / SX, etc.). In the context of this example, the non-metallic frame 2321 performs at least one of four functions: 1) defining the center of the piezoelectric material 2322 along the longitudinal axis 101 (Figure 1) and width axis 108 (Figure 1) of the planar linear array 100 (Figure 1); 2) defining the height (Figure 1) of the planar linear array 100 (Figure 1, 101); 3) including a ground trench 2323 that provides a ground connection from the front to the back of the piezoelectric layer 2320 (forming part of the return signal path); and 4) suppressing stress applied to the piezoelectric layer 2320 material during the manufacturing processes 2300, 2400.

[0145] The piezoelectric layer 2320 can function as a pure 1-3 composite used in transducers, including ultra-high frequency transducers operating at ultrasonic frequencies above 15 MHz. As described above, the transducers described herein can operate at frequencies ranging from low to ultra-high frequencies. The non-metallic frame 2321 holds the piezoelectric material 2322 in place such that it is centered along the width axis 108 (Figure 1) and the longitudinal axis 101 (Figure 1). The non-metallic frame 2321 defines its vertical width by controlling the width of the central opening (also called the active surface) based on its positioning along the width axis 108 (Figure 1) and the longitudinal axis 101 (Figure 1) (where the piezoelectric material 2322 is positioned). For example, the non-metallic frame 2321 can maintain a consistent vertical width. The non-metallic frame 2321 also provides a grounding path from the piezoelectric material 2322 to a flexible circuit (e.g., Figure 1, 130) via a ground trench 2323. In some examples, a ground trench includes a series of holes (e.g., round and / or rectangular holes). While the piezoelectric layer 2320 is shown in the context of the planar linear array 100 in Figure 1, the piezoelectric layer 2320 is also used in further devices and may replace the piezoelectric layer in these devices. As mentioned above, this specification uses the term trench to describe different types of fissures within a material. In Figure 4, the trench is a literal ground trench 423, which is a more traditionally understood concept, although in this example the ground trench 2323 could be more accurately described as a groove. The structure of this element is flexible and can vary depending on the resulting transducer, hence the use of the term "trench" in such general embodiments. Grounding paths such as trenches and their internal elements provide a grounding connection from one side to the other of the piezoelectric layer 2320 (forming part of the return signal path). In some examples, the trench 423 includes a series of holes, including, but not limited to, round and / or rectangular holes. The trench provides a grounding connection from one side to the other.

[0146] Transducers manufactured according to the methods described herein can operate at high and very high frequencies, but in some examples, the manufacturing methods described herein can be used to manufacture transducers that operate over a wide frequency range. For example, several methods described herein can be used to manufacture arrays that can cover operating center frequencies from at least ~1 MHz to ~70 MHz.

[0147] Referring to Figures 23 and 24, in order to manufacture the piezoelectric layer 2320 (2300, 2400), the nonmetallic frame 2321 and the piezoelectric material 2322 are both prepared separately before being incorporated into the piezoelectric layer 2320. To prepare the nonmetallic frame 2321, the nonmetallic frame 2321 (piezoelectric frame) is formed by pre-dicing or machining two (e.g., two or three or more) ground trenches 2323 into the nonmetallic frame 2321 (2410). To prepare the piezoelectric material 2322, the piezoelectric material 2322 is diced to fit within the nonmetallic frame 2321 (2415). To set the shape, size and thickness of the piezoelectric material 2322, the material itself can be pre-diced into sections or array elements of the desired shape, size and thickness for the desired application. Since the piezoelectric material 2322 is placed within a piezoelectric layer 2320 of a frame not formed from the piezoelectric material, the amount of piezoelectric material 2322 within the piezoelectric layer 2320 is limited to the minimum length necessary to cover the active region. This configuration of the piezoelectric layer 2320 (e.g., including a non-metallic frame 2321) represents a cost reduction in the manufacturing process. In a non-limiting example, the piezoelectric material 2322 is cut to a precise size of 46.0 mm × 2.8 mm with a vertical width of 2.4 mm. Dicing the piezoelectric material 2322 to only the size that covers the active region is a departure from previous methods in which the piezoelectric material 2322 was diced to a size larger than the active region, and then only the area covering the active region was processed, leaving excess around the edges where a ground connection was formed. Once the piezoelectric material 2322 and nonmetallic frame 2321 are prepared (along with a ground trench 2323 which can be formed using a laser or otherwise pre-machined), the piezoelectric material 2322 (e.g., PZT) can be bonded 2328 within the nonmetallic frame 2321 (e.g., piezoelectric frame) (2420). The bond 2328 may consist of a binder such as an adhesive and / or epoxy that does not degrade during use of the resulting transducer.

[0148] Once the piezoelectric material 2322 is bonded 2328 within the non-metallic frame 2321 (2420), the piezoelectric material 2322 can be thinned to a desired thickness by removing excess adhesive and / or residue and making the surface of the piezoelectric material 2322 uniform (2430). To make the surface uniform, various techniques can be used, including, but not limited to, lapping (including parallel lapping), grinding, shaving, and / or machining. The piezoelectric material 2322 can then be kerf-cut 2327 (2440). Various examples of kerf-cuts are shown in Figure 5 of this specification. However, in some examples, instead of cutting both short and long notches, it is possible to cut a notch in only one direction (e.g., a single cut) into the piezoelectric material 2322 instead of the standard short / long notches found in some existing transducers. Performing such a kerf-cut makes it possible to fill the kerf with different types of materials, including materials that harden quickly. Therefore, in the example shown in Figure 23, a usable piezoelectric layer 2320 can be produced despite the accelerated hardening process, allowing for the use of various kerf filling materials. In some existing high-frequency transducers, using a piezoelectric layer 2320 with a non-metallic frame 2321 adds further stability to the piezoelectric layer 2320, thus protecting the piezoelectric material 2322 and reducing the likelihood of damage being prevented by a long hardening time, which can result in a longer hardening process.

[0149] As described above, the calf is filled with calf filler 2325 (2450). The calf 2327 of the piezoelectric layer 2320 can be filled with various types of materials, including, but not limited to, liquids or solids such as polymers. In these examples, a faster-curing calf filler 2325 can be used. In some examples, the calf filler can be cured in as little as one day to maintain the structural integrity of the piezoelectric layer 2320 and the resulting transducer. In general, existing transducers that include a piezoelectric layer formed of piezoelectric material instead of using a non-metallic frame 2321 cure over at least five days. Therefore, by incorporating a non-metallic frame element into the piezoelectric layer, the manufacturing time can be reduced by shortening the time used for curing the material filling the kerf of the piezoelectric material. As shown in Figures 23 and 24, the material is cured (2460), and once curing is complete (e.g., after 1 day), the ground trench 2323 is lapped and cleaned (e.g., to remove any undesirable filler material that may have moved during the curing process), and the piezoelectric layer 2320 can be made to the desired thickness (2470). Referring to Figure 9, the piezoelectric layer 920 shows the desired thickness of the piezoelectric layer 2324 (Figure 23). In some examples, the piezoelectric layer 2320 can be lapped down to a height of ~100 microns. Since the kerf material has a shorter curing time compared to conventional methods, the lapping process is simplified. After lapping, the surface of the piezoelectric layer 2320 is sputtered with gold 2329 so that the gold 2329 covers the piezoelectric material 2322 (2480). Rather than sputtering the entire piezoelectric layer as is done in some existing methods, the sputtering can be targeted to cover the active region (e.g., the piezoelectric material 2322), thus avoiding the risk that the sputtering will adversely affect the piezoelectric layer 2320.

[0150] The configuration of the piezoelectric layer 2320 offers various advantages to the manufacturing process and the integrity of the resulting ultrasonic transducer. For example, the non-metallic frame 2321 provides the ultrasonic transducer with an additional structure to prevent warping of the piezoelectric material 2322 during use. Also, as shown in Figure 24, when constructing the piezoelectric layer 2320, ground trenches 2323 are formed in the piezoelectric layer 2320, so the non-metallic frame 2321 also protects the piezoelectric material 2322 during manufacturing. In existing transducer stacks, trenches are formed in the piezoelectric material itself, specifically in the piezoelectric material surrounding the portion of the piezoelectric layer on the active surface. However, since the piezoelectric material is continuous, laser cutting trenches into a portion of the piezoelectric layer may affect the structural integrity of the entire layer. Therefore, by pre-machining the trenches, the piezoelectric material is not exposed to the heat associated with trench formation, preventing warping, combustion, or other deformation as a result of the heat. For example, the piezoelectric layer can often crumble due to thermal deformation of the material, but the pre-machined non-metallic frame 2321 protects the entire piezoelectric layer 2320 and the piezoelectric material 2322 from crumbling. The configuration of the piezoelectric layer 2320 also reduces pitch error or walk-off. The ground trenches 2323 are machined into the non-metallic frame 2321 before the piezoelectric material 2322 is bonded to the non-metallic frame 2321, so the piezoelectric material 2322 is less likely to warp through the heating process that causes pitch error or walk-off. Heat can also cause pitch error or walk-off of kerf.

[0151] Some existing piezoelectric layers have ground trenches or ground slots (sometimes multiple ground slots) machined into the portion of the piezoelectric material that does not cover the active surface, but this portion is the same as the portion of piezoelectric material that covers the active surface. For example, if grounding for a piezoelectric layer is drilled using a high-power laser process, the entire layer may be exposed to heat and its dimensions may change, meaning that the slots may no longer be at optimal distance from each other. Some existing piezoelectric layers contain multiple ground slots, but some examples of piezoelectric layer 2320 described herein contain only two ground trenches. In one example, piezoelectric layer 2320 contains a single ground trench. Reducing the number of ground vias also reduces the possibility of pitch error or walk-off. Drilling slots or channels of any type directly into the piezoelectric material may create stress points in the material. The methods shown in Figures 23 and 24 avoid this step, thus preserving the integrity of the piezoelectric material.

[0152] Referring again to Figures 23 and 24, to form a grounding path utilizing the trench 2323, the trench can be pre-filled with a conductive material such as silver-filled epoxy, and then the tapered structure 2343 can be mounted on the filled trench 2323 to form a grounding path (2490). This filling ensures electrical conductivity from ground to the tapered support structure 2343. In some examples herein, such support structures are shown as tapered supports due to the cross-sectional shape of the support structure used in the disclosed transducer. However, in various examples herein, any shape can be used, whether tapered or otherwise, as long as it provides the advantages of the illustrated examples; therefore, this shape is merely one type of geometric configuration for the support structure. Thus, for example, Figure 23 shows a tapered support structure 2343, but further shapes of support structures can also be incorporated into the examples herein.

[0153] Referring to the non-limiting example shown in Figure 23, the tapered structure 2343 (in this example) can be attached with bonding adhesive and functions as a grounding path located on the open-slot trench 2323. In this non-limiting example, there are only two grounding trenches 2323, so aligning the tapered structure 2343 to function as a grounding path is simpler than some existing piezoelectric layers that can include multiple slots instead of these two trenches 2323 (shown in Figure 25 as upper trench 2523a and lower trench 2523b). The tapered support and configuration of this trench 2323 is shown only as an example of a possible configuration. In Figure 25, both the upper trench 2523a and lower trench 2523b ground the transducer, although in some examples the upper trench 2523a is slightly narrower than the lower trench 2523b. In other examples the lower trench 2523b can be narrower than the upper trench 2523a. As shown in Figure 23 and described above, the non-metallic frame 2321 can be formed in various patterns (e.g., machining, molding, casting, 3D printing, etc.) and combined with different types of supports to form grounding paths. The tapered support 2343 in Figure 23 is provided to demonstrate the flexibility of the piezoelectric layer 2320 and the ease with which it can be incorporated into known configurations. Compared to the examples of transducers herein that include an interposer frame, the tapered support 2343 can be understood as an alternative or substitute for an interposer frame (e.g., Figure 9, 925) because it provides a support structure that can combine rigidity, grounding paths, and an overmolding (e.g., Figure 932) similar to that of an interposer frame (e.g., Figure 9, 925).

[0154] Figure 25 is a detail view of a piezoelectric layer 2520, an example of a piezoelectric layer shown in Figures 4 and 23. As shown in Figure 25, the piezoelectric layer 2520 of a transducer may include a non-metallic frame 2521 (piezoelectric frame) and a piezoelectric material 2522 (shown as PZT in Figure 25). The non-metallic frame 2521 (piezoelectric frame) includes two ground trenches 2523a and 2523b (collectively 2523), also called cutouts, as they were pre-machined before the piezoelectric layer 2520 was assembled. In this non-limiting example, the widths of the ground trenches 2523 (cutouts) differ, but are approximately 0.4 mm to the edge of the piezoelectric layer 2520. The figure also specifies the piezoelectric margin 2531 and the vertical width / opening width 2532.

[0155] During the manufacturing of piezoelectric layers 2320 and 2520, the layers can be constructed in a batch process, which is more advantageous than manufacturing several existing piezoelectric layers individually. Figure 26 shows the various steps of process 2600 for producing a batch of piezoelectric layers (e.g., piezoelectric layers 2320 and 2520). This example shows a batch of eight piezoelectric layers, but this example is provided only to illustrate the process, and batches of different sizes can be constructed depending on the machinery and / or available space. In some examples, a wrapping machine can perform the process.

[0156] Figure 26 shows workflow 2600, which includes elements that help illustrate the workflow. As shown in Figure 26, workflow 2600 begins by placing foil or sheet material 2611 on a surface (2610) including, but not limited to, a plate (not shown). Examples of foil 2611 include gold, silver, aluminum, and plastic. Individual stencils 2612 can be placed on the foil 2611 (of piezoelectric layers (e.g., piezoelectric layers 2320, 2520, 2620)). The illustrated stencils 2612 are merely examples of stencil shapes that can be used to guide the placement of the piezoelectric material 2622 portions of the resulting piezoelectric layers (e.g., piezoelectric layers 2320, 2520). These stencils 2612 (which offer non-limiting options) have openings that allow for targeted placement of binders, including, but not limited to, cyanoacrylate. The stencil 2612 is used as a placement guide (2630) to bond the pre-diced piezoelectric material 2622 onto the foil 2611. Once the piezoelectric material 2622 is in place, the non-metallic frame 2621 can be bonded to the piezoelectric material 2622 (or the piezoelectric material 2622 to the non-metallic frame 2621) (2640). A second plate (not shown) can be placed on the assembly to hold the resulting piezoelectric layers (e.g., piezoelectric layers 2320, 2520) parallel to each other while the adhesive cures. Once the bond is secure (e.g., when the adhesive has cured if an adhesive is used as the binder), the plate, excess binder and foil 2611 can be removed (before calf-cutting, filling, and / or sputtering the piezoelectric layers) leaving the piezoelectric layers (e.g., piezoelectric layers 2320, 2520). Figure 27 shows a cross-section 2700 of a single piezoelectric layer 2720 located between the first plate 2766 and the second plate 2767. In the cross-section 2700, the foil 2711, stencil 2712, piezoelectric material 2722, and nonmetallic frame 2721 are visible.

[0157] Figures 28, 29, 30, and 31 show planar structures described herein, which, unlike some other examples, include a tapered structure 2343 (e.g., Figure 23) which may be called and / or understood as such. This tapered structure 2343 (e.g., Figure 23) is used in place of the interposer frames 125, 1225, 1325, and 1425 (Figures 12, 13, and 14, respectively) in the planar structure. In embodiments of planar structures including the tapered structure 2343 (e.g., Figure 23), the tapered structure 2343 is coupled to overmoldes 932, 1032 (e.g., Figures 9 and 10) and one or more flex circuits 930 (Figure 9). These embodiments are shown in Figures 28, 29, and 30.

[0158] Comparing this configuration to other configurations described herein, Figure 28 is similar to Figure 1 but includes a tapered structure 2843 and excludes the interposer frame 125 (Figure 1). Figure 28 is an exploded view of an example of a planar linear array stack for ultrasonic transducers having a tapered structure 2843. Figure 29 is similar to Figure 10 in that it shows views of various elements of the planar linear array stack described herein, but this example includes a tapered structure 2943. Figure 30 is a magnified side view of several planar linear array stacks described herein, similar to Figure 14, but Figure 30 includes a tapered structure 3043. Although the support is described herein as a tapered support, the descriptor tapered is only used as an example, as this structure can take various forms in different embodiments of the planar linear arrays for transducers described herein.

[0159] Figure 28 is an exploded view of an example of a planar linear array stack 2800 for ultrasonic transducers. Several embodiments are described in general terms in this figure, and these embodiments are described in more detail in the following figures. The illustrated example of the planar linear array stack 2800 includes an indicator of width on the longitudinal axis 2801, also called the longitudinal axis 2801, the width axis 2808, and the stack-up thickness 2809. In this specification, references to the bottom of the planar linear array stack 2800 mean the planar linear array stack 2800 starting from the lens layer 2810. In this specification, references to the top of the planar linear array stack 2800 mean the planar linear array stack 2800 starting from the bending spacer 2845. Thus, as in the description of Figure 1, when it is described in Figure 28 that the first element is located below the second element, it means that the first element is closer to the lens layer 2810 than the second element. When describing the first element as being located above the second element, it means that the first element is closer to the bending spacer 2845 than the second element.

[0160] Referring to Figure 28, the planar linear array stack 2800 includes a lens layer 2810. This lens layer 2810 may include acoustic lenses fixed to a lens support structure, or, in some examples, the lens layer 2810 may include acoustic lenses without a lens support structure. The acoustic lenses used in various examples may be concave or convex. As an example, the acoustic lenses shown in the figures herein are concave only.

[0161] The planar linear array stack 2800 also includes a piezoelectric layer 2820 containing a piezoelectric material (e.g., PZT, PZT / SX, etc.) 2822. Although the piezoelectric material 2822 and piezoelectric layer 2820 are shown as rectangular, their shapes can vary in various embodiments, and the rectangle was chosen for these examples for ease of explanation and does not imply limitation. Various embodiments of the present invention may include piezoelectric material 2822 and piezoelectric layer 2820 of various shapes, including rectangular, polygonal (including non-rectangular polygons), oval, elliptical, circular, and the like, but are not limited to the present invention.

[0162] As shown in the following figures, the piezoelectric layer 2820 (e.g., Figures 25, 2520) includes a frame 2821 (e.g., Figures 25, 2521) which is not made of metal (e.g., can be formed of ceramic), and is referred to herein as a “non-metallic frame”. In some examples, the non-metallic frame 2821 surrounds four sides of the piezoelectric material 2822 (e.g., Figures 25, 2522). The frame 2821 of the piezoelectric layer 2820 can position the piezoelectric material 2822 at a central position (or any other desired position such as an offset from the central position) with respect to the longitudinal axis 2801 and the width axis 2808 of the planar linear array stack 2800. The non-metallic frame 2821 of the piezoelectric layer 2820 can not only position the piezoelectric material 2822 (e.g., PZT) with respect to the width axis 2808 and the longitudinal axis 2801 in the planar linear array stack, but can also define the elevation depth (e.g., the stack-up thickness 2809 dimension).

[0163] In some examples, such as the planar linear array stack 2800 in Figure 28, at least one matching layer 2815 separates the lens layer 2810 and the piezoelectric layer 2820. The matching layer 2815 can provide a material buffer from acoustic impedance between elements in the transducer containing insulating elements and elements through which the signal passes. The surface of the piezoelectric material 2822 of the piezoelectric layer 2820 adjacent to at least one matching layer 2815 may include at least one electrode. This surface electrically couples the piezoelectric material 2822 with at least one matching layer 2815. Above the piezoelectric layer 2820, there is a tapered structure 2843 (e.g., Figures 23, 2343) that is useful for arranging one or more flex circuits 2830. In some examples, one or more flex circuits 2830 are coupled to the tapered structure 2843.

[0164] For ease of explanation, only a single flex circuit 2830 is shown in Figure 28. Multiple flex circuits can also be used, as described in the following figures, and these flex circuits can electrically couple the tapered structure 2843 to the piezoelectric layer 2820. The flex circuits 2830 can also be further coupled to the ground electrode. Flex locator tabs 2844 on the overmolding 2832 are involved in coupling one or more flex circuits 2830 to the tapered structure 2843. The flex circuits 2830 include flex alignment strips 2833 (e.g., Figure 8, 833). In some examples, each flex alignment strip 2833 bonds four flex circuits 2830. The flex alignment strips 2833 can provide array elements with precise alignment (e.g., linear alignment) with a 90-micron pitch. The overmolding 2832 secures the flex circuits 2830 to the tapered structure 2843. The backing preform 2840 conforms to the planar structure and reduces material costs because the volume of the backing preform is smaller than that of other structural guides and is formed to conform to the planar structure on the planar linear array. The backing preform 2823 accommodates the bending spacers 2846 used to guide one or more flex circuits 2830.

[0165] Figure 29 is an alternative diagram (in comparison with Figure 28) of various elements of the planar linear array stack described herein (here the planar stack includes tapered structures 2843, 2943). These figures are provided before describing structures used to transmit electrical signals from the tapered structure 2943 to traces on the surface of one or more flex circuits 2930 (flex alignment strips 2933 are also shown), uniform-scale conductive shapes (e.g., Figures 10, 1050). In this specification, the uniform-scale conductive shapes in Figure 10, which are also present in this example but not visible from the viewpoint of Figure 29, are shown as spheres, but these shapes can include pyramids, cubes, etc., so the spheres are provided as a non-limiting example. Shapes including uniform-scale conductive shapes in the planar linear array stack can be uniform or mixed and can have a uniform height along the stack-up depth axis (Figure 28). In different examples, the materials and their arrangement of these shapes can vary, and may include fingers of pure gold (facing each other) in direct contact, Cu fingers, silver (which can improve the burden of electrical contact rate), and / or Cu fingers facing upward on the flex.

[0166] A planar linear array 2900, shown in Figure 29, moves upward along the stack-up thickness 2809 axis from the lens layer 2810 to the bending spacer 2845 (e.g., Figure 28), and includes a lens layer 2910 which may include an acoustic lens having a curved portion. One or more matching layers 2915 are present above the upper surface of the lens layer 2910. The upper surface of the lens layer 2910 is bonded to the piezoelectric layer 2920 and / or matching layers 2915 by a binder including, but not limited to, a lens adhesive 2934. The piezoelectric layer 2920 includes a piezoelectric material 2822 (Figure 28) and may include electrodes on both sides, a non-metallic frame 2821 (Figure 28), and a ground trench 2923. The flex circuit 2930 can be connected to the ground electrode after bending. This connection is further shown and described in detail in Figure 9B.

[0167] The tapered structure 2943 is partially located on the horizontal plane above the piezoelectric layer 2920 (with a stack-up thickness of 2809, relative to Figure 28). An overmolded structure 2932 is present on the surface including the top surface of the tapered structure 2943. The overmolded structure may include electrodes (e.g., gold, copper) on its top surface. In the illustrated example, the top surface of the overmolded structure 2932 includes copper fingers 2963 as conductive shapes. As described above, various examples of this specification may include various different types of conductive shapes. As shown in Figure 29, the overmolded structure 2932 includes a separation ridge 2951 and trenches 2952 below the separation ridge 2951. These trenches 2952 are coated with a conductive material, including, but not limited to, gold. In some examples, the trenches 2952 are gold channels. The overmolded structure 2932 and one or more flex circuits 2930 are coupled to the tapered structure 2943.

[0168] Figure 30 is an enlarged view of a planar array 3000 including a tapered structure 3043. The overmolded 3032 and one or more flex circuits 3030 are coupled to the tapered structure 3043 and the flex alignment strip 3033. To illustrate the orientation of the tapered structure 3043 within the array (e.g., Figures 28, 2800), Figure 30 shows elements described in other figures, such as lens layers 2810, 2910, 3010, overmolded 2832, 2932, 3032, and flex alignment strips 2833, 2933, 3033. Figure 30 also shows a piezoelectric layer 3020 and a matching layer 3015.

[0169] Figure 31 is a top view of an embodiment of the planar array 3100 described herein. Figure 31 shows (in a partially exploded view) tapered structures 2843, 2943, 3043, and 3143 partially separated from the piezoelectric layers 2820, 2920, 3020, and 3120. The tapered structures 3143 are coupled to the overmolded 3132. Figure 31 further shows the piezoelectric layers 2820, 2920, 3020, and 3120, which consist of lens layers 2810, 2910, 3010, and non-metallic frames 2821, 3121 surrounding the four sides of the piezoelectric material 2822, 3122. Below the piezoelectric layer 3120 is the lens layer 3110.

[0170] Examples described herein include piezoelectric layers for ultrasonic transducers, ultrasonic transducers, methods for manufacturing transducers, and methods for manufacturing piezoelectric layers for ultrasonic transducers. In some examples of piezoelectric layers for ultrasonic transducers, the piezoelectric layer includes a nonmetallic frame. In these examples, the piezoelectric layer also includes a piezoelectric material. The nonmetallic frame surrounds at least two sides of the piezoelectric material and is coupled to a lens support structure having a structure such that the acoustic lens and the piezoelectric material are oriented substantially parallel to each other. The piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens.

[0171] In some examples of piezoelectric layers, the non-metallic frame includes ceramic.

[0172] In some examples of piezoelectric layers, the nonmetallic frame includes at least one notch on one or more of the at least two sides of the nonmetallic frame, and the at least one notch on one or more of the at least two sides forms part of the grounding path.

[0173] In some examples of piezoelectric layers, at least one notch includes a groove.

[0174] In some examples of piezoelectric layers, the piezoelectric material includes a calf cut filled with a hardened calf filler material.

[0175] In some examples of piezoelectric layers, the piezoelectric layer further includes a sputtered metal layer on the surface of the piezoelectric material.

[0176] In some examples of piezoelectric layers, at least two sides include four sides, and the piezoelectric material is rectangular, trapezoidal, oval, elliptical, circular, or square.

[0177] In some examples of piezoelectric layers, the structure includes a tapered structure.

[0178] In some examples, the ultrasonic transducer includes a planar linear array stack. In these examples, the planar linear array stack may include a lens layer comprising an acoustic lens and a lens support structure, and a piezoelectric layer. The piezoelectric layer may include a nonmetallic frame and a piezoelectric material. In some examples, the nonmetallic frame surrounds at least two sides of the piezoelectric material. The nonmetallic frame is coupled to a lens support structure having a structure such that a portion of the acoustic lens and a portion of the nonmetallic frame are oriented substantially parallel to each other, and the piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens. The structure positions one or more flex circuits, and the one or more flex circuits are coupled to the structure.

[0179] In some examples of ultrasonic transducers, the lens support structure includes a first bar and a second bar, with the first and second bars located on either side of the acoustic lens.

[0180] In some examples of ultrasonic transducers, the lens support structure includes a frame that surrounds the periphery of the acoustic lens.

[0181] In some examples of ultrasonic transducers, the lens support structure includes ceramic.

[0182] In some examples of ultrasonic transducers, the acoustic lens includes a curved portion whose extremum lies on a line parallel to the piezoelectric material in a planar linear array stack.

[0183] In some examples of ultrasonic transducers, the acoustic lens contains a dielectric material.

[0184] Some examples of ultrasonic transducers include a tapered structure.

[0185] In some examples of ultrasonic transducers, a non-metallic frame surrounding the piezoelectric material is bonded to the outer boundary of the piezoelectric material with a binder.

[0186] In some examples of ultrasonic transducers, a planar linear array stack includes one or more matching layers between the lens layer and the piezoelectric layer.

[0187] In some examples of ultrasonic transducers, the piezoelectric layer includes electrodes on a surface adjacent to one or more matching layers.

[0188] In some examples of ultrasonic transducers, a planar linear array stack includes an overmolding that secures one or more flexible circuits to the structure.

[0189] In some examples of ultrasonic transducers, a planar linear array stack includes one or more flexible alignment strips attached to one or more flexible circuits, and at least one flexible alignment strip is positioned on an overmolded surface by at least one flexible locator tab.

[0190] In some examples of ultrasonic transducers, a planar linear array stack includes a backing preform that contacts a portion of one or more flexible circuits.

[0191] In some examples of ultrasonic transducers, the backing preform is covered with conductive tape.

[0192] In some examples of ultrasonic transducers, the planar linear array stack includes a bending spacer. In these examples, the bending spacer is positioned above the backing preform such that a portion of each flex circuit is perpendicular to the piezoelectric layer of the planar linear array stack.

[0193] In some examples, the ultrasonic transducer includes a planar linear array stack. The planar linear array stack may include a lens layer containing lenses, one or more matching layers between the lens layer and the piezoelectric layer, and the piezoelectric layer. The piezoelectric layer may include a nonmetallic frame and piezoelectric material. In these examples, the nonmetallic frame surrounds at least two sides of the piezoelectric material, and the nonmetallic frame is coupled to part of a lens support structure having a structure such that the acoustic lens and the nonmetallic frame are oriented substantially parallel to each other, and the piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens. The structure may accommodate one or more flex circuits, and one or more flex circuits are coupled to the structure.

[0194] An example of a method for manufacturing the piezoelectric layer of an ultrasonic transducer may include dicing a piezoelectric material to form piezoelectric material pieces of a certain size, where dicing includes sizing the piezoelectric material pieces to cover an area equivalent to the active surface of the acoustic lens of the ultrasonic transducer. The method may include assembling a four-sided frame from a non-metallic material. The method may include forming at least one trench on at least one of the two parallel sides of the four-sided frame. The method may include bonding piezoelectric material pieces of a certain size to a four-sided frame such that the four-sided frame surrounds at least two sides of the piezoelectric material of a certain size. The method may include cutting the piezoelectric material of a certain size to form one or more kerfs oriented in a consistent direction. The method may include filling the kerfs with a material that hardens over a certain period of time. The method may include sputtering at least a certain size of piezoelectric material pieces with a conductive material based on the passage of time.

[0195] In some examples of the method, the method further includes bonding a piezoelectric layer to a structure, and based on this bonding, at least one trench on at least one of two parallel sides forms part of a grounding path to the structure.

[0196] In some examples of the method, the method further includes wrapping a piezoelectric material piece of a certain size before kerf cutting.

[0197] In some examples of the method, the method further includes wrapping and cleaning each trench before sputtering.

[0198] In some examples of this method, the conductive material is a metal.

[0199] In some examples of the method, the metal is selected from the group consisting of gold, silver, and copper.

[0200] In some examples of the method, at least one trench is selected from the group consisting of notches, channels, holes, grooves, slots, waterways, corrugations, folds, crimps and cuts.

[0201] In some examples of the method, the duration is one day or less.

[0202] In some examples of the method, when a piezoelectric layer is implemented on an ultrasonic transducer, at least one trench is involved in providing a ground connection from the front to the back of the piezoelectric layer, forming part of the return signal path for the ultrasonic transducer.

[0203] In some examples of the method, the wrapping includes parallel wrapping.

[0204] An example of a method for manufacturing the piezoelectric layer of an ultrasonic transducer may include dicing a piezoelectric material to form one or more piezoelectric material pieces of a fixed size, wherein dicing includes sizing each of the one or more fixed-size piezoelectric material pieces to cover at least the area of ​​the active surface of the acoustic lens of the ultrasonic transducer. The method may also include assembling one or more tetrahedron frames from a nonmetallic material. The method may include forming at least one trench on each side of two parallel sides of each frame of the one or more tetrahedron frames. The method may include stretching and arranging a foil on an object including a first parallel surface. The method may include arranging one or more stencils on the upper surface of the foil, wherein each stencil of the one or more stencils includes an opening for receiving and holding each fixed-size piece of the one or more fixed-size pieces in a set position. The method may include using each stencil of the one or more stencils to arrange each fixed-size piece of the one or more fixed-size pieces. The method may include joining each nonmetallic frame of the one or more nonmetallic frames to each fixed-size piece of the one or more fixed-size pieces. The method may include arranging a second object, which includes a second parallel plane parallel to a first parallel plane, on one or more non-metallic frames.

[0205] In some examples, the method includes removing a first object, a second object, one or more stencils, and foil to form one or more piezoelectric layers.

[0206] In some examples, joining each nonmetal frame of one or more nonmetal frames to each of one or more pieces of a fixed size includes arranging each piece of a fixed size such that the nonmetal frames surround at least two sides of each piece of a fixed size.

[0207] In some examples, each of the multiple pieces of a fixed size is a shape selected from the group consisting of rectangles, ovals, circles, non-rectangular polygons, and circles.

[0208] In some cases, removal is carried out using a process selected from the group consisting of lapping, grinding, and milling.

[0209] In some examples, the method includes, for each piezoelectric layer of one or more piezoelectric layers, kerf-cutting a piezoelectric material of a certain size to form one or more kerfs oriented in a consistent direction; filling the kerfs with a material that hardens over a certain period of time; and, based on the passage of time, sputtering piezoelectric material pieces of at least a certain size with a conductive material.

[0210] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of instructions containing one or more executable instructions for performing a specified (single or multiple) logical function. In some alternative implementations, the functions shown in the blocks may occur in a different order than that shown. For example, depending on the related functions, two consecutively shown blocks may actually be executed substantially simultaneously, or sometimes the blocks may be executed in reverse order. Furthermore, each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, may be implemented by a dedicated hardware-based system that performs a specified function or action, or a combination of dedicated hardware and computer instructions.

[0211] The terms used herein are for the sole purpose of describing specific embodiments and are not intended to be limiting. The singular English articles ("a," "an," and "the") used herein are intended to include plural forms unless the context clearly indicates otherwise. Furthermore, the terms “comprises and / or comprising” as used herein specify the presence of the features, integers, steps, actions, elements, and / or components referred to, but are not intended to exclude the presence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof.

[0212] Where corresponding structures, materials, actions, and equivalents exist for all means or step-plus-function elements within the following claims, these are intended to include any structure, material, or action for performing the function in combination with any other elements specifically claimed. While descriptions of one or more embodiments are provided for illustrative and explanatory purposes, they are not intended to be exhaustive or limit the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are selected and described in a manner that best illustrates various aspects and practical applications, and that allows other persons skilled in the art to understand various embodiments with various modifications suitable for the specific intended use. [Explanation of symbols]

[0213] 100 Planar Linear Array Stack 101 Longitudinal axis 108 Width axis 109 stacking thickness 110 lens layers 115 Matching layer 120 Piezoelectric layer 125 Interposer Frame 126 Cavity 130 Flex Circuit 132 Overmolding 135 Flex Bending Frame 136 Cavity 140 Backing Preforms 145 Bending Spacer

Claims

1. A piezoelectric layer of an ultrasonic transducer, Non-metallic frame, Piezoelectric materials and, Includes, The non-metallic frame surrounds at least two sides of the piezoelectric material, and the non-metallic frame is coupled to a lens support structure having a structure such that the acoustic lens and the piezoelectric material are oriented substantially parallel to each other, and the piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens. Piezoelectric layer.

2. The piezoelectric layer according to claim 1, wherein the nonmetallic frame includes ceramic.

3. The piezoelectric layer according to claim 1, wherein the nonmetallic frame includes at least one notch on one or more of the at least two sides of the nonmetallic frame, and the at least one notch on the one or more of the at least two sides forms part of a grounding path.

4. The piezoelectric layer according to claim 3, wherein the at least one of the notches includes a groove.

5. The piezoelectric layer according to claim 1, wherein the piezoelectric material includes a calf cut filled with a hardened calf filler material.

6. The piezoelectric layer according to claim 1, further comprising a sputtered metal layer on the surface of the piezoelectric material.

7. The piezoelectric layer according to claim 1, wherein the at least two sides include four sides, and the piezoelectric material is rectangular, trapezoidal, oval, elliptical, circular, or square.

8. The piezoelectric layer according to claim 1, wherein the structure includes a tapered structure.

9. An ultrasonic transducer including a planar linear array stack, The aforementioned planar linear array stack is A lens layer including an acoustic lens and a lens support structure, Piezoelectric layer and The piezoelectric layer includes, Non-metallic frame, Piezoelectric materials and, Includes, The non-metallic frame surrounds at least two sides of the piezoelectric material, and the non-metallic frame is coupled to the lens support structure having a structure such that a portion of the acoustic lens and a portion of the non-metallic frame are oriented substantially parallel to each other, and the piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens. The structure positions one or more flexible circuits, and the one or more flexible circuits are coupled to the structure. Ultrasonic transducer.

10. The ultrasonic transducer according to claim 9, wherein the lens support structure includes a first bar and a second bar, the first bar and the second bar being located on both sides of the acoustic lens.

11. The ultrasonic transducer according to claim 9, wherein the lens support structure includes a frame surrounding the peripheral edge of the acoustic lens.

12. The ultrasonic transducer according to claim 9, wherein the lens support structure includes ceramic.

13. The ultrasonic transducer according to claim 9, wherein the acoustic lens includes a curved portion, and the curved portion has an extremum on a line parallel to the piezoelectric material in the planar linear array stack.

14. The ultrasonic transducer according to claim 9, wherein the acoustic lens includes a dielectric material.

15. The ultrasonic transducer according to claim 9, wherein the structure includes a tapered structure.

16. The ultrasonic transducer according to claim 9, wherein the non-metallic frame surrounding the piezoelectric material is bonded to the outer boundary of the piezoelectric material with a binder.

17. The ultrasonic transducer according to claim 9, wherein the planar linear array stack includes one or more matching layers between the lens layer and the piezoelectric layer.

18. The ultrasonic transducer according to claim 17, wherein the piezoelectric layer includes electrodes on a surface adjacent to the one or more matching layers.

19. The ultrasonic transducer according to claim 9, wherein the planar linear array stack includes an overmolding, and the overmolding fixes the one or more flex circuits to the structure.

20. The ultrasonic transducer according to claim 19, wherein the planar linear array stack includes one or more flexible alignment strips attached to the one or more flexible circuits, and the at least one flexible alignment strip is positioned on the overmolded by at least one flexible locator tab.

21. The ultrasonic transducer according to claim 16, wherein the planar linear array stack includes a backing preform that contacts a portion of the one or more flex circuits.

22. The ultrasonic transducer according to claim 21, wherein the backing preform is covered with conductive tape.

23. The ultrasonic transducer according to claim 21, wherein the planar linear array stack includes a bending spacer, the bending spacer is positioned above the backing preform such that a portion of each flex circuit is perpendicular to the piezoelectric layer of the planar linear array stack.

24. An ultrasonic transducer including a planar linear array stack, The aforementioned planar linear array stack is A lens layer including the lens, One or more matching layers between the lens layer and the piezoelectric layer, Piezoelectric layer and The piezoelectric layer includes, Non-metallic frame, Piezoelectric materials and, Includes, The non-metallic frame surrounds at least two sides of the piezoelectric material, and the non-metallic frame is coupled to a part of the lens support structure having a structure such that the acoustic lens and the non-metallic frame are oriented substantially parallel to each other, and the piezoelectric material is sized to cover an area greater than or equal to the active surface of the acoustic lens. The structure positions one or more flexible circuits, and the one or more flexible circuits are coupled to the structure. Ultrasonic transducer.

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