Planar Linear Array for Ultrasonic

Abstract

The ultrasonic transducer includes a planar array stack. The stack includes a lens layer that includes an acoustic lens and a lens support structure, and a portion of the acoustic lens is fixed to the lens support structure. The stack also includes a piezoelectric layer that includes a non-metallic frame and a piezoelectric material, the non-metallic frame surrounds the piezoelectric material on at least two sides, and the non-metallic frame is coupled to a portion of the lens support structure such that the acoustic lens and the non-metallic frame are oriented substantially parallel to each other. The transducer also includes an interposer frame for positioning one or more flex circuits, and the interposer frame is coupled to the non-metallic frame and to one or more flex circuits through conductive elements within the non-metallic frame.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This PCT international patent application claims priority to U.S. Patent Application No. 63 / 368,756, entitled "PLANAR LINEAR ARRAY FOR ULTRASOUND", filed on July 18, 2022, and U.S. Patent Application No. 18 / 158,904, entitled "PLANAR LINEAR ARRAY FOR ULTRASOUND", both of which are hereby incorporated by reference in their entirety.

Background Art

[0002] In conventional ultrasound diagnostic imaging systems, an array is used as an interface that converts an electrical signal into ultrasound and reconverts the reflected ultrasound from the received tissue structure back into an electrical signal. Certain arrays utilize a fixed acoustic lens, such as a convex RTV (room - temperature vulcanizing silicone) lens, in the elevation direction to focus the ultrasound beam to improve image resolution or image slice thickness. Currently, the most common ultrasound transducers in medical imaging are 1D arrays that utilize a fixed aperture with an acoustic lens within the elevation to improve image resolution. The transducer elements can be arranged in a linear 1D row or chain (so - called linear array) and can be controlled separately or in groups by an electronic control unit to achieve an orientation effect. Elevation resolution can be improved by using a controlled multi - row array (e.g., 1.25D or 1.5D) for elevation aperture adjustment, but the cost of constructing a multi - row array in production is high due to the complex electrical interconnections between rows and columns. The complexity of these connections also broadens the possibility of malfunction and can affect the lifespan of the device. In addition, although the elevation direction resolution can be improved, current multi - row arrays introduce the limitation that all rows typically have the same center frequency.

[0003] A certain array used for ultrasonic imaging is a free-field voltage sensitivity (FFVS) high-frequency (HF) array and is constructed on a tapered metal support structure. The existing structures used to mount these arrays increase the complexity of the resulting probe, as it has been demonstrated that mounting in various ways at an angle is necessary for the functionality and structural integrity of the array. For example, mounting the flex circuit of the array at an angle equal to or near 45 degrees on this tapered support structure maintains lateral space and creates a vertical electrical path by adding a molded insulating layer. The metal within the tapered support structure provides mechanical strength to the array structure and functions as a ground path. However, the slanted nature of this structure that provides the desired functionality makes assembly difficult, as described above. Existing ultrasonic transducers have a composite 3D structure within their array stack. Assembling these stacks is a long process that involves complex setups by operators with a high level of skill. Summary of the Invention Means for Solving the Problems

[0004] The disadvantages of the prior art can be overcome, and the benefits as described later in the disclosure of the present invention can be achieved by providing a transducer. Various examples of the transducer are described below, and transducers that include and exclude any combination (on the premise that these combinations are not contradictory) of the additional embodiments listed below overcome these disadvantages. The transducer includes, for example, a lens layer including an acoustic lens and a lens support structure, wherein a portion of the acoustic lens is fixed to the lens support structure, and a piezoelectric layer including a non-metallic frame and a piezoelectric material, wherein the non-metallic frame surrounds the piezoelectric material on at least two sides, and the non-metallic frame is coupled to a portion of the lens support structure such that the acoustic lens and the non-metallic frame are oriented substantially parallel to each other, a planar array stack including the piezoelectric layer, an interposer frame for positioning one or more flexible circuits, the interposer frame being coupled to the non-metallic frame and to one or more flexible circuits through conductive elements within the non-metallic frame, and the one or more flexible circuits.

[0005] The disadvantages of the prior art can be overcome, and the benefits as described later in the disclosure of the present invention can be achieved by providing a transducer. Various examples of the transducer are described below, and transducers that include and exclude any combination (on the premise that these combinations are not contradictory) of the additional embodiments listed below overcome these disadvantages. The transducer includes, for example, a lens layer including a lens, one or more matching layers between the lens layer and the piezoelectric layer, and the piezoelectric layer including a non-metallic frame and a piezoelectric material, wherein the non-metallic frame surrounds the piezoelectric material on at least two sides, a planar array stack including the piezoelectric layer, an interposer frame for positioning one or more flexible circuits, the interposer frame being coupled to the non-metallic frame and to one or more flexible circuits through conductive elements within the non-metallic frame, and the one or more flexible circuits.

[0006] The drawbacks of the prior art can be overcome, and the benefits, as will be described later in the disclosure of the present invention, can be achieved by providing a transducer. Various examples of the transducer are described below, and transducers that include and exclude any combination (on the premise that these combinations are not contradictory) of the additional embodiments listed below overcome these drawbacks. The transducer includes, for example, a lens layer including a lens, and a piezoelectric layer including a non-metallic frame and a piezoelectric material, wherein the non-metallic frame surrounds the piezoelectric material on at least two sides, and the non-metallic frame is coupled to a portion of the lens layer, a planar array stack including the piezoelectric layer, an interposer frame for positioning one or more flexible circuits, the interposer frame being coupled to the non-metallic frame through conductive elements within the non-metallic frame and to the one or more flexible circuits, and the one or more flexible circuits.

[0007] The drawbacks of the prior art can be overcome, and the benefits, as will be described later in the disclosure of the present invention, can be achieved by providing a method of fabricating a transducer. Various examples of the method are described below, and the method that includes and excludes any combination (on the premise that these combinations are not contradictory) of the additional embodiments listed below overcome these drawbacks. The method includes, for example, forming a piezoelectric layer including a non-metallic material and a piezoelectric material, the forming including assembling the piezoelectric material with the non-metallic material on at least two sides. The method can also include forming a lens support structure that directs an acoustic lens to a central position with respect to the width and elevation of the planar array stack. The method can also include adhering the lens support structure to the piezoelectric layer such that the lens support structure and the piezoelectric layer are parallel with respect to the width and elevation.

[0008] Additional features are realized through the devices and techniques described herein. Other embodiments and aspects are described in detail herein and are considered to be part of the claimed aspects.

[0009] One or more aspects are specifically pointed out and expressly claimed by way of example in the appended claims of this specification. The foregoing and the objects, features, and advantages of one or more aspects will be apparent from the following detailed description taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

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Best Mode for Carrying Out the Invention

[0011] The drawings are not drawn to scale for ease of understanding, and like reference numerals may refer to the same or functionally similar elements throughout the separate drawings. The accompanying drawings, which are incorporated herein and constitute a part hereof, illustrate the invention in more detail and, together with the detailed description of the invention, explain the principles of the invention. As will be understood by those skilled in the art, the accompanying drawings are provided for ease of understanding and show aspects of certain embodiments of the invention. The invention is not limited to the embodiments depicted in these drawings.

[0012] Term Examples As used herein, terms such as "connecting," "connected," "contacting," and / or "coupled" are defined broadly to include a variety of different arrangements and assembly techniques. These arrangements and techniques include (1) the direct joining of one component to another without any intervening components (i.e., the components are in physical direct contact), and (2) the joining of one component to another with one or more intervening components, where one of the components that is "connected to," "in contact with," or "coupled to" the other component is in operative communication with the other component in some manner (e.g., electrically, fluidically, physically, and / or optically, etc.) (including, but not limited to, such joining on the premise that such operative communication exists despite the presence of one or more additional intervening components). It is understood that some components that are in physical direct contact with each other may or may not be in electrical and / or fluidic contact with each other. Further, two components that are electrically coupled, electrically connected, optically connected, optically coupled, fluidically connected, or fluidically coupled may or may not be in physical direct contact, and one or more other components may be disposed between these components.

[0013] As used herein, the term "including" means the same as the term "comprising."

[0014] Terms such as "substantially", "approximately", "about", "relatively", or other similar such terms that can be used throughout the disclosure of the present invention including the claims represent and are used to account for minor variations from a standard or parameter due to, for example, variations in processing. Such minor variations include zero variation from the standard or parameter. For example, these variations can mean variations less than or equal to ±10%, such as variations less than or equal to ±5%, variations less than or equal to ±2%, variations less than or equal to ±1%, variations less than or equal to ±0.5%, variations less than or equal to ±0.2%, variations less than or equal to ±0.1%, variations less than or equal to ±0.05%, etc. When used herein, the terms "substantially", "approximately", "about", "relatively", or other similar such terms may mean no variation.

[0015] As used herein, "electrical coupling" means the transfer of electrical energy between a power source, an electrode, a conductive surface, a droplet, a conductive trace, a wire, a waveguide, a nanostructure, other circuit segments, and the like, in any combination. The term "electrical coupling" can be used with respect to direct or indirect connections, and the electrical coupling may pass through various media such as a fluid medium and a void.

[0016] As used herein, the term "kerf" refers to an adjustable gap between die-cut portions of an acoustic surface, which can be filled with different materials in each embodiment (for maintaining and adjusting these gaps).

[0017] The term "ROC" means radius of curvature and is used in this specification in the context of acoustic design. In a medical ultrasound array, generally, an ROC lens is a cylindrical focusing lens. The lenses referred to as ROC lenses in this specification are single-radius focusing lenses, and the lenses referred to as multi-ROC lenses in this specification are multi-radius focusing lenses. The ROC for a convex acoustic lens is the product of the geometric focal length and a value smaller than the result of dividing the speed of sound in the medium by the speed of sound in the lens material. The acoustic lenses used in this specification are designed based on the paraxial theory or Fresnel approximation in geometric optics assuming a plane wavefront emitted in a direction perpendicular to the transducer surface.

[0018] When used in this specification, the term "PZT" means lead zirconate titanate or lead zirconium titanate, which is a ceramic perovskite material that exhibits the piezoelectric effect, i.e., it changes shape when an electric field is applied. Against the backdrop of exhibiting this piezoelectric effect, PZT is used for ultrasonic transducers. PZT ceramics are the most commonly used piezoelectric ceramics because they have higher sensitivity and operating temperature than other piezoelectric ceramics. When used in this specification, when the term "SX" is used together with "PZT" as in "PZT / SX", it means a single-crystal lead zirconate titanate layer or a single-crystal lead zirconium titanate layer.

[0019] When used in this specification, the term "matching layer" means a layer that helps transmit ultrasonic energy from an element to a medium within a transducer array. The matching layer is generally positioned between the element and the lens in the examples described in this specification (as well as in existing transducer arrays). The matching layer includes, but is not limited to, epoxy, elastomer, polyurethane, polystyrene, etc., and is composed of a material having conductivity for providing an acoustic impedance gradient for the acoustic energy from the transducer to smoothly penetrate the body tissue and for the reflected acoustic wave (return echo) to smoothly return to the transducer for detection.

[0020] As used herein, the terms "signal flex" and "ground return flex" mean signal elements and ground return elements within a flexible electronic device, also known as a flex circuit, which is a circuit that can be shape adapted (e.g., bent during use) to a desired shape. The term "flex" refers to the flex circuit. Flex circuits are utilized as connectors in various applications where flexibility, space savings, and / or productivity constraints limit the usefulness of rigid circuit boards or manual wiring. Many flex circuits are passive wiring structures used to interconnect electronic components.

[0021] As used herein, the term "stack configuration" means the stacking of objects referred to herein as "stacks" that include multiple piezoelectric layers diced into multiple rows in the elevation direction, as well as matching layers and in some cases detuning layers, in the context of the embodiments described herein. As described herein, each stack configuration is represented with respect to three dimensions, namely, the width in the elevation direction, the length perpendicular to this width, and the stack thickness configuration perpendicular to the length and also perpendicular to the width. Examples of these dimensions are provided in FIG. 1 herein.

[0022] As used herein, the term "beam pattern" (which may also be referred to as an 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, as well as the size, shape, and acoustic phase characteristics of the vibrating surface. The beam pattern of a transducer is reciprocal, i.e., the beam is the same regardless of whether the transducer is used as a transmitter or a receiver. In general, a transducer can be designed to radiate sound in many different types of patterns, from an omnidirectional beam to a very narrow beam.

[0023] As discussed herein, a "phased array" (PA) refers to an ultrasonic transducer array that causes individual elements on the array to emit in a specific order to direct sound waves in a specific direction. For this purpose, a PA probe is composed of many (e.g., small) ultrasonic transducers that can be pulsed independently. As a result of changing the timing by this pulsing (e.g., gradually delaying the pulses from each transducer when moving a linear array), the probe emits a beam pattern due to constructive interference of set angles based on a gradual time delay. By changing the gradual time delay, the beam is electronically steered.

[0024] The term "excimer laser", also referred to herein as "exciplex laser" when used herein, refers to a form of ultraviolet (UV) laser.

[0025] The term "lens layer" as used herein means one or more elements within the planar linear array stack described herein that can include an acoustic lens fixed to a lens support structure or, in some embodiments, the lens layer can include an acoustic lens without a lens support structure.

[0026] The term "piezoelectric layer" as used herein refers to a layer within a planar array stack that can include a piezoelectric material (e.g., such as PZT, PZT / SX). As discussed in more detail herein, in some embodiments, the piezoelectric layer is not composed of metal (e.g., can include ceramics) and can include a frame that assembles (surrounds) the piezoelectric material on at least two sides. In this specification, this frame is referred to as a "non-metallic frame".

[0027] As used herein, the term "interposer frame" refers to a structure within a planar array stack that is a non-conductive structure that can be used to position conductive elements, including one or more flex circuits, in the embodiments described herein. The interposer frame can include a solid material (e.g., ceramic) coated with a conductive layer for bridging a ground connection and a signal electrode connection within the planar array stack.

[0028] As used herein, the term "overmold" refers to a material that can be used to bond and position elements within a planar array stack. In the embodiments described herein, the overmold can be used to position conductive elements such as one or more flex circuits.

[0029] As used herein, the term "flexure bending frame" refers to an element of a planar array stack that can be used to shape the above-described conductive elements positioned by the interposer frame.

[0030] As used herein, the term "backing preform" refers to a backing layer within a planar array stack that can be used to enhance the signal quality of a transducer by absorbing and attenuating back-end signals from ceramic elements (e.g., interposer frames).

[0031] As used herein, the term "bending spacer" refers to a spacer that can assist in bending a conductive element (e.g., a flex circuit) based on positioning in the embodiments described herein (the spacer can be used in a transducer to reduce side imaging and interference).

[0032] As used herein, the term "uniform-scale conductive shape" refers to shapes including, but not limited to, spheres, pyramids, and cubes. The term "uniform scale" refers to a shape having a uniform height (e.g., stack thickness). In this specification, the relative orientation of height measurements is discussed.

[0033] As discussed above, some existing arrays used in ultrasonic transducers are configured on a tapered metal support structure, which is an example of a composite three-dimensional (3D) structure utilized in this technology. These tapered structures can provide mechanical strength to the array structure by means such as maintaining lateral space and can further function as a ground path. However, as a result, a composite 3D structure that can be difficult (and expensive) to assemble is brought about. Similarly, the function of miniaturizing the array is limited by the need to bend the flex circuit (e.g., by 45 degrees), which can make the resulting probe inappropriate for certain applications. Further, in a composite 3D structure, it can be difficult to generate flat and parallel surfaces with a certain tolerance. As the footprint of the array increases, as in the case of an ultra-high resolution endorectal ultrasound (UHR-TRUS) probe, it becomes more difficult to maintain flatness with a strict tolerance. As the footprint decreases, it becomes difficult to handle such a very small array and manufacture tools for assembling components thereon. As will be described below, there is a need to reduce 3D complexity and bulk in the transducer array regardless of whether the array includes either a tapered support structure or another existing 3D structure with a similar bulk. The examples described herein take this need into account.

[0034] This specification describes a method of manufacturing an ultrasonic transducer including a planar array stack, and an example of a transducer including this planar array stack. By using a transducer having an example of the planar structure described in this specification, when compared with existing non-planar examples, the manufacturing process is simplified without degrading the acoustic quality, and at the same time the yield is improved. The examples of the planar array structure described in this specification can be integrated into a UHR-TRUS probe. Various aspects of the examples described in this specification will be discussed, but certain examples include: 1) a substantially flat (e.g., planar) intervening frame that can include, but is not limited to, non-metallic materials including ceramics; 2) electrical connections that utilize a shape coated with a conductive material; 3) a piezoelectric frame (also referred to herein as a layer) that is non-conductive (e.g., ceramic), increases mechanical strength, facilitates manufacturing by flattening the array, and is used to provide an embedded conductive channel for grounding; 4) a backing preform that conforms to the planar structure and reduces material costs; 5) a lens layer that can include a lens with or without a surrounding frame. The lens frame, if present, will improve mechanical strength and electrically safe insulation. The advantages of the examples of the arrays described in this specification and the manufacturing processes suitable for these examples include, but are not limited to, simplifying manufacturing tools, eliminating manufacturing processes that consume long hours, reducing the difficulty of manufacturing, reducing dependence on operator skills, reducing the defect rate, and reducing the cost of reduction.

[0035] FIG. 1 depicts an exploded assembly view of Example 100 of a planar array stack for an ultrasonic transducer. In this figure, certain aspects are outlined, and the figures that follow this figure illustrate these aspects in more detail. For example, FIGS. 2 and 3 show various aspects of lens layers 210, 310 within the planar array stack 100 (FIG. 1). FIG. 4 is a top view of various aspects of piezoelectric layer 420 within the planar array stack 100 (FIG. 1), whereas FIG. 5 depicts various examples of piezoelectric materials that are part of piezoelectric layer 120 (FIG. 1) within the planar linear array described herein. FIG. 6 depicts an overmold 632 that secures flex circuit 630 to interposer frame 625. FIG. 7 depicts an example 725 of an interposer frame. FIG. 8 depicts a flex circuit structure that includes flex alignment strip 833 and flex circuit 830. FIGS. 12 and 13 show flex bending frames 1235, 1335. FIG. 15 shows a backing preform 1540. FIG. 20 depicts a bending spacer 2045. The content of the remaining figures is also described below in this specification.

[0036] Referring to FIG. 1, the illustrated Example 100 of the planar array stack includes labeling of width 101, width 108, and stack thickness 109 in the elevation direction, also denoted as elevation 101. References herein to the bottom of planar array stack 100 mean the location where planar array stack 100 begins with lens layer 110. References herein to the top of planar array stack 100 mean the location where planar array stack 100 begins with bending spacer 145. Thus, when it is described that a first element is positioned below a second element, it means that the first element is closer to lens layer 110 than the second element. When it is described that a first element is above a second element, it means that the first element is closer to bending spacer 145 than the second element.

[0037] Referring to FIG. 1, the planar array stack 100 includes a lens layer 110. This lens layer 110 can include an acoustic lens fixed to a lens support structure, or in some embodiments, the lens layer 110 can include an acoustic lens without a lens support structure. The acoustic lenses utilized for various examples can be concave or convex. The depiction of the acoustic lens in the figures described herein is only concave as an example.

[0038] The planar array stack 100 further includes a piezoelectric layer 120 of a piezoelectric material (such as PZT, PZT / SX, etc.). As illustrated in later figures, this piezoelectric layer 120 is not composed of metal (can be manufactured from ceramic) and includes a frame referred to herein as a "non-metal frame" that assembles (surrounds) the piezoelectric material on at least two sides. In some embodiments, the non-metal frame surrounds the piezoelectric material on four sides. This frame can position the piezoelectric material at a central position with respect to height 101 and width 108 within the planar array stack 100. The non-metal frame of the piezoelectric layer 120 not only positions the piezoelectric material centrally with respect to width 108 and elevation 101 within the planar array stack but also defines the depth in the elevation direction.

[0039] In some embodiments of the planar array stack 100, the non-metallic frame of the piezoelectric layer 120 is coupled to a portion of the lens support structure such that the acoustic lens and the non-metallic frame are oriented substantially parallel to each other along the axis of the stack thickness 109. In some embodiments, such as the planar array stack 100 of FIG. 1, at least one matching layer 115 separates the lens layer 110 and the piezoelectric layer 120. The matching layer 115 can provide a substantial buffer from the acoustic impedance between the elements within the transducer including the insulating element and the elements through which the generated signal will pass. The surface of the piezoelectric material near the at least one matching layer 115 within the piezoelectric layer 120 can include at least one electrode that electrically couples the piezoelectric material and the at least one matching layer 115. Above the piezoelectric layer 120 is an interposer frame 125 that disposes one or more flexible circuits 130. The interposer frame 125, which can include a ceramic or solid material, is non-conductive and is used to anchor conductive materials and / or interconnect conductive elements into the planar array stack 100, thereby enabling conductivity. In some embodiments, a conductive layer is added to the interposer frame 125 such that the interposer layer 125 can bridge the ground connection and the signal electrode connection within the planar array stack 100.

[0040] For ease of illustration, FIG. 1 shows only a single flex circuit 130. As illustrated in subsequent figures, multiple flex circuits can be used, and these flex circuits can electrically couple the interposer frame 125 to the piezoelectric layer 120. The flex circuit 130 can, in addition, be coupled to a ground electrode. Although not shown in FIG. 1, a plurality of uniform scale shapes (e.g., metal micro shapes) coated with or composed entirely of a conductive material can couple the interposer frame 125 to the flex circuit 130. A sphere is used as an example of a throughout shape, but it will be understood by those skilled in the art that conductive shapes that can be utilized for the various examples herein can include, but are not limited to, pyramids and cubes, provided that the height of the shape (e.g., stack thickness 109) is uniform (when positioned). Various shapes can be mixed with each other.

[0041] In FIG. 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 than them) and above the piezoelectric layer 120 (i.e., closer to the bending spacer 145 than it), and the flex bending frame 135 is substantially parallel to a first portion of one or more flex circuits 130 (along the axis of the stack thickness 109). The overmold 132 fixes the flex circuit 130 to the interposer frame 125. As illustrated herein, the second portion of each flex circuit of one or more flex circuits 130 is substantially perpendicular to the plane of the flex bending frame 135 along the width 108 of the planar linear array 100 (e.g., this portion of one or more flex circuits 130 is substantially perpendicular to the plane defined by the dimension of the width 108 and the dimension of the elevation 101, and the plane of the flex bending frame 135 is substantially parallel to this plane), and this portion of one or more flex circuits 130 is bent in the direction of the stack thickness 109. Therefore, a portion of the bent flex circuit can be perpendicular to the axis of the width 108 of the planar array stack 100, and one or more flex circuits 130 can be shaped using the flex bending frame 135 so as to be bent in the direction of the stack thickness 109.

[0042] As shown in FIG. 1, both the interposer frame 125 and the flexure bending frame 135 have cavities 126, 136. When stacked within the planar array stack 100, these cavities 126, 136 fit precisely together, creating an opening or cavity at a central location along the width 108 and elevation 101 of the planar array stack 100. A portion of the backing preform 140 extends through this opening (created by 126, 136). A portion of each of the one or more flex circuits 130 is substantially parallel to the surface of the bending spacer (along the width 108), while other portions of the one or more flex circuits 130 are bent so as to be perpendicular to the width 108 of the planar array stack (extending in the direction of the stack thickness 109). A bending spacer 145 that helps to bend / position the one or more flex circuits 130 is positioned above the backing preform 140 along the stack thickness 109.

[0043] FIGS. 2 and 3 depict examples of lens layers 210, 310 (e.g., 110 of FIG. 1) that can be integrated into examples of the planar array stacks described in this specification, which include but are not limited to the planar array stack 100 of FIG. 1. The difference between the lens layer 210 of FIG. 2 and the lens layer 310 of FIG. 3 is the lens support structures 212, 312 used to position the acoustic lenses 211, 311 in each example.

[0044] In the lens layer 210 of FIG. 2, the support structure 212 for the acoustic lens 211 includes a first bar 213a and a second bar 213b located on both sides of the acoustic lens 211. The acoustic lens 211 can include, but is not limited to, a dielectric material including Rexolite (registered trademark). The material of the support structure 212 can be selected based on having a thermal expansion rate similar to that of the acoustic lens 211 in order to minimize any distortion including bending of the lens layer 210 when exposed to heat (e.g., during use of an ultrasonic transducer). Avoiding the expansion difference between the acoustic lens 211 and the support structure 212 is desirable for the integrity and lifespan of the planar array stack 100 (FIG. 1) and any transducer integrated therein. The material constituting the support structure 212 can include, but is not limited to, ceramic, gypsum with ceramic, and gypsum with metal (e.g., silver, gold).

[0045] As will be understood by those skilled in the art, the acoustic lens 211 can be used to focus an ultrasonic beam to improve the sensitivity of an image. For this purpose, a predetermined radius of curvature (ROC) is provided to properly focus the ultrasonic beam within the acoustic lens 211. Accordingly, the acoustic lens 211 of FIG. 2 includes a curved portion 214. The support structure 212 within the lens layer 210, when integrated into a planar array stack (e.g., 100 of FIG. 1), positions the curved portion 214 at coordinates of a width 108 and an elevation 101 similar to those of the piezoelectric material within the piezoelectric layer (e.g., 120 of FIG. 1). This positioning centers the acoustic lens 211 and the piezoelectric material along the width 108 and the elevation 101 of the planar array stack 100.

[0046] In the lens layer 310 of FIG. 3, the support structure 312 for the acoustic lens 311 includes a frame 313 placed around the perimeter of the acoustic lens 311. This acoustic lens can include, but is not limited to, a dielectric material including Rexolite®. Similar to the case of the support structure 212 in FIG. 2, within the lens layer 310 of FIG. 3, based on having a thermal expansion rate similar to that of the acoustic lens 311 in order to minimize any distortion including the bending of the lens layer 310 when exposed to heat (during the use of the ultrasonic transducer), the material of this support structure 312 can likewise be selected. Avoiding the expansion difference between the acoustic lens 311 and the support structure 312 is desirable for the integrity and lifespan of the planar array stack 100 (FIG. 1) and any transducer integrated therein. The material constituting the support structure 312 can include, but is not limited to, ceramics, gypsum with ceramics, and gypsum with metals (e.g., silver, gold). The acoustic lens 311 can include a curved portion 314, and the portion of the support structure 312 that abuts the curved portion 314 can also include this shape as shown in FIG. 3. The support structure 312 within the lens layer 310, when integrated into a planar array stack (e.g., 100 of FIG. 1), positions the curved portion 314 of the lens at a central location along the width 108 (FIG. 1) and elevation 101 (FIG. 1) of the planar array stack.

[0047] FIG. 4 depicts an embodiment of the piezoelectric layer 420, another embodiment of which is depicted as the piezoelectric layer 120 in FIG. 1. The top view provided in FIG. 4 depicts an embodiment 420 of the piezoelectric layer including a non-metallic frame 421 that can include, but is not limited to, an insulating material including ceramics. In the context of this embodiment, the non-metallic frame 421 provides at least one of three functions: 1) the function of positioning the piezoelectric material 422 centrally along the elevation 101 (FIG. 1) and width 108 (FIG. 1) of the planar linear array 100 (FIG. 1), 2) the function of defining the elevation (e.g., 101 of FIG. 1) of the planar linear array 100 (FIG. 1), and 3) the function of including a ground trench 423 for routing (forming part of the return signal path) a ground connection from the front surface to the back surface of the piezoelectric layer 420.

[0048] The non-metallic frame 421 surrounds a piezoelectric material 422 (such as PZT, PZT / SX, etc.). The piezoelectric layer 420 functions as a high-purity 1-3 composite used in a high-frequency converter. The material itself can be pre-die cut into sections or array elements of a desired shape, size, and thickness suitable for the desired use to set the shape, size, and thickness of the piezoelectric material 422. In one non-limiting example, the piezoelectric material 422 is cut to an exact size of 46.0 mm × 2.8 mm with an elevation width of 2.4 mm. Next, the PZT is glued into the piezoelectric frame 421. This structure can be used to manufacture a high-purity 1-3 composite and use it for a high-frequency converter. The non-metallic frame 421 holds the piezoelectric material 422 in a fixed position such that the piezoelectric material 422 is centered over the width 108 (FIG. 1) and the elevation 101 (FIG. 1). The non-metallic frame 421 defines an equal elevation width by controlling the width of the central opening based on the positioning according to the width 108 (FIG. 1) and the elevation 10 (FIG. 1) in which the piezoelectric material 422 is positioned. The non-metallic frame 421 also provides a grounding path from the piezoelectric material 422 through the grounding trench 423 to a flex circuit (such as 130 in FIG. 1). For electrical connections within a planar linear array, it will be discussed in more detail in the discussion of FIGS. 9A and 9B, referred to herein as FIG. 9 for each other.

[0049] The non-metallic frame 421 maintains the rigidity of the piezoelectric material 422 and improves the lifespan of the piezoelectric material 422 that functions as the active area of the piezoelectric layer 420. As described above, the piezoelectric material 422 can be sized according to the intended use of the resulting transducer. In the embodiment shown in FIG. 4, the non-metallic frame 421 surrounds the piezoelectric material 422 on four sides, while in some embodiments it surrounds on two sides. In some embodiments, the non-metallic frame 421 positions the piezoelectric material 422 to be centered with respect to the width 108 (FIG. 1) and elevation 101 (FIG. 1) within a planar array stack (e.g., 100 of FIG. 1). In the case of the lens layer (e.g., 210 and 310 described respectively in FIGS. 2 and 3), an element centered with respect to the width 108 (FIG. 1) and elevation 101 (FIG. 1) by a support structure can be fixed to the support structure using an adhesive or epoxy that will not deform during use of the resulting transducer.

[0050] The piezoelectric material 422 can be sized according to the intended use of the resulting transducer. The piezoelectric material 422 can vary in size, and in some embodiments is sized the same as the acoustic lens (e.g., 211 and 311 described respectively in FIGS. 2 and 3). The non-metallic frame 421 can position the piezoelectric material 422 such that it is in substantially the same location as the acoustic lens (e.g., 211 and 311 described respectively in FIGS. 2 and 3) with respect to the width 108 (FIG. 1) and elevation 101 (FIG. 1) of the planar array stack, but at different coordinates on the axis representing the stack thickness 109 (FIG. 1). Thus, in these embodiments, the lens layer (e.g., 210 and 310 described respectively in FIGS. 2 and 3) and the piezoelectric layer 420 are substantially parallel to each other within the planar array stack (e.g., 100 of FIG. 1).

[0051] The non-metallic frame 421 can include one or more grounding trenches 423 as shown in FIG. 4. To fabricate the grounding trench 421 within the non-metallic (e.g., ceramic) frame 421, in one embodiment, a trench is drilled within the non-metallic frame 421 and filled with a first conductive material metal (e.g., silver, gold), and the filled trench is coated with a second conductive material to provide the grounding trench 423, as will be discussed later with respect to the method of manufacturing the planar array stack disclosed herein. These conductive materials may be the same or different. For example, the grounding trench can be coated with gold and filled with solder epoxy. Providing the grounding trench 423 within the non-metallic frame 421 means a grounding connection for a simple array when compared to the grounding connection in an existing array. Since exposed electrodes that may interfere with the desired planar quality of the array when using piezoelectric materials are commonly utilized, signal grounding can sometimes be difficult to fabricate. In the embodiments herein, the non-metallic frame 421 acts as an insulator around the grounding trench 423 and can be flush with the upper surface of the piezoelectric layer 420, so the planar (flat) quality of the array is maintained.

[0052] Returning to the piezoelectric material 422 itself, the piezoelectric material 422 includes one or more kerfs cut in a pattern. The timing of cutting the pattern into the piezoelectric material 422 can be varied. In some embodiments, the piezoelectric material 422 is patterned before assembling the piezoelectric layer 410. In other embodiments, the piezoelectric material 422 is patterned after assembling the piezoelectric layer 410. Different patterns can be selected depending on the intended use of the transducer. In still other embodiments, the piezoelectric material 422 is patterned both before and after assembling the piezoelectric layer 410.

[0053] FIG. 5 shows different patterns that can be formed in piezoelectric material 422 using a laser either before or after integrating the piezoelectric material 422 into piezoelectric layer 420 by adhering the piezoelectric material 422 to non-metallic frame 421 by a procedure that includes, for example, gluing non-metallic frame 421 to piezoelectric material 422 or vice versa. These patterns include a first pattern 502, a second pattern 503, and a third pattern 504. Similarly, FIG. 5 also illustrates an elevation 505 (e.g., elevation 101 of FIG. 1) and a thickness 506 (e.g., stack thickness 109 of FIG. 1) of the piezoelectric material for each pattern. As will be appreciated by those skilled in the art, the piezoelectric material can be patterned in a conventional sub-die pattern where the transducer element is split longitudinally along its center by a single sub-die scribe. This sub-die scribe has the same length as the length of the transducer element. As will be appreciated by those skilled in the art, the width / height ratio of the transducer element must be less than or equal to the "golden ratio" of about 0.6 in order to minimize the lateral vibration mode in PZT. As shown in FIG. 5, each pattern includes a main scribe 507 which is the above-described sub-die scribe that re-divides the dielectric (e.g., piezoelectric) material. The main scribe 507 can be scribed between each element at the above-described pitch. The sub-die cut scribe is scribed at the center of each element. In addition to the main scribe 507, the second pattern 503 further includes a square pattern, while the third pattern 504 further includes a parallelogram pattern. These patterns can be utilized, for example, in a 90 micron pitch array. In some embodiments, a laser including, but not limited to, an excimer laser can machine the piezoelectric material 422 to generate these scribes. For example, the laser can scribe a kerf of 8 - 10 microns into a piezoelectric material such as a PZT ceramic to a depth of ~100 microns and form a kerf of about 35 microns in the piezoelectric material 422. In some embodiments, the laser is also used to perform reverse cuts to maintain the uniformity of the kerf width along the vertical structure.

[0054] As shown in FIG. 1, the planar linear array stack 100 can include an interposer frame 125 that positions one or more flexible circuits 130. FIG. 6 depicts a structure 600 that functions to secure a flexible circuit within a planar linear array stack. This structure 600, shown in FIG. 6 as an exploded view, includes the aforementioned interposer frame 625 (e.g., 125 in FIG. 1), the aforementioned flexible circuit 630 (e.g., 130 in FIG. 1), and an overmold 632 that secures the flexible circuit 630 to the interposer frame 625. In some embodiments, the overmold 632 includes electrodes on its surface, and these electrodes can include a conductive material such as a metal (e.g., gold, silver). The electrodes can be channels that include but are not limited to gold channels. For example, the overmold can include gold foil. The flexible circuit 630 includes traces (not depicted in FIG. 6) of a conductive material (such as copper (Cu), gold, and / or silver) on a certain surface. FIG. 6 does not include a flexible alignment strip, which is discussed below. In this embodiment of FIG. 6, the interposer frame 625 is positioned under one or more flexible circuits 630, while the overmold 632 helps secure one or more flexible circuits 630 to the interposer frame 625.

[0055] Figures 7 and 8 provide additional insights into the embodiment of FIG. 6. Since the interposer frame 625 is somewhat difficult to see in FIG. 6, for ease of understanding, FIG. 7 shows only the interposer frame 725 itself. On the other hand, FIG. 8 depicts a flexible circuit structure 800 including a flexible alignment strip 833 and a flexible circuit 830. In various examples of the planar linear arrays described herein, the flexible alignment strip 833 is positioned between the interposer frame 625 and the flexible bending frame 135 (e.g., FIG. 1) and is substantially parallel to a portion of one or more flexible circuits 830. As shown in FIG. 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 high-precision alignment (e.g., linear alignment) with array elements at a pitch of 90 microns.

[0056] Figures 9 and 10 provide another view (when compared to FIG. 1) of various elements of the planar linear arrays described herein. These figures are provided before describing the structures used to transmit electrical signals from the surface of the interposer frame 625 (FIG. 6) to traces on the surface of one or more flexible circuits 630 (FIG. 6), uniform-scale conductive shapes 950, 1050 (FIGS. 9, 10) in some embodiments. FIG. 9B provides an additional embodiment of the electrical connection of ground from one or more piezoelectric materials to a flexible circuit 930. Further, FIG. 9A shows one or more flexible circuits 930 before being bent, while FIG. 9B shows one or more flexible circuits 930 after being bent. Although uniform-scale conductive shapes (950, 1050 (FIGS. 9, 10)) are exemplified as spheres herein, the shapes can include pyramids, cubes, etc., so the sphere is provided as a non-limiting example. The shapes including uniform-scale conductive shapes within the planar array stack can be uniform or mixed and can have a uniform height along the axis of the stack depth 109 (FIG. 1).

[0057] Starting from the bottom of this portion of the planar linear arrays 900, 1000 shown in FIGS. 9 and 10 and moving upward (e.g., in FIG. 1, from the lens layer 110 along the axis of the stack thickness 109 to the bending spacer 145), the array includes lens layers 910, 1010 that include acoustic lenses 911 having a curved portion 914. Above the upper surfaces of the lens layers 910, 1010, there are one or more matching layers 915, 1015. The lens adhesives 934, 1034 bond the upper surface of the 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 materials 922, 1022 having electrodes on both sides, non-metallic frames 921, 1021, and ground trenches 923, 1023. The flex circuits 930, 1030 are connected to the ground electrodes 947 after being bent. This connection is described and illustrated in more detail in FIG. 9B.

[0058] The interposer frames 925, 1025 including conductive electrodes and / or traces (e.g., gold, copper, silver) are positioned on a horizontal plane above the piezoelectric layers 920, 1020 (with respect to the stack thickness 109 in FIG. 1). FIGS. 9A and 10 show the flex circuits 930, 1030 before being bent, which is the reason why the entire flex circuits 930, 1030 are parallel to the piezoelectric layer 920 (i.e., they are at different coordinates along the axis of the stack thickness 109 in FIG. 1 but have shared coordinates with respect to the width 108 and elevation 101). FIG. 9B shows the flex circuit 930 after being bent. The interposer frames 925, 1025 include conductive electrodes and / or traces (e.g., gold, copper, silver) in this embodiment. There are overmolds 932, 1032 on the surface including the upper surface of the interposer frame 925. The overmolds include electrodes (e.g., gold) on their upper surfaces. As shown in FIG. 10, the structure of the overmold 1032 includes a separation ridge 1051 and a trench 1052 lower than it. These trenches 1052 are coated with a conductive material including but not limited to gold.

[0059] The spacer frames 925, 1025 are electrically coupled to one or more flex circuits 930, 1030 through one or more uniform-scale conductive shapes 950, 1050 coated with a conductive material (e.g., such as gold, silver). In this non-limiting example, the surfaces of the spacer 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 conduct electrical signals from the surface of the spacer frames 925, 1025 in contact with this shape to the traces on the surface of one or more flex circuits 930, 1030 in contact with this shape. Each shape is composed of a dielectric material and can be uniformly coated with a conductive material. When the array is oriented as in the embodiment of FIG. 9, the uniform-scale conductive shape 950 forms a vertical electrical connection.

[0060] FIG. 9B shows various elements of the planar linear array 900, with an emphasis on the electrical connection for grounding from the piezoelectric layer 920 to one or more flexes 930 (shown as connection 947 in FIG. 9A). FIG. 9B shows an example of a portion of the planar linear array 900 in which one or more flexes 930 are bent into their final configuration (FIG. 9B illustrates only a single flex representative of one or more flexes for simplicity of illustration). Similarly, FIG. 9B includes diagrams of the insulating and conductive portions of the planar linear array 900. In FIG. 9B, the electrical path 941 indicates the connection 947 (e.g., FIG. 9A).

[0061] Electrical path 941 is a ground path that forms a return signal path. Electrical path 941 shows a ground path from ground, through the ground plane 939 of one or more flexes 930, through the conductive layer 943 on the interposer frame 925 (as previously discussed, the interposer frame 925 includes a conductive electrode and / or trace (e.g., gold, copper, silver) as the conductive layer), and into the ground trench 923 on the piezoelectric layer 920. The ground path that is electrical path 941 travels from the ground trench 923 on the piezoelectric layer 920 to the non-metallic frame 921 and then to one or more flexes 930 through the conductive electrode on the interposer frame 925. The ground trench 923 includes a conductive material including but not limited to epoxy. In this embodiment, the interposer frame 925 includes an electrical insulating material 946 including but not limited to epoxy and a conductive material 949 that can also be epoxy. The conductive material 949 can be adjacent to the electrical path 941, and at the same time the electrical insulating material 946 bridges the conductive layer 943 on the interposer frame 925 and the conductive material 949. The connection between the conductive layer 943 (which can include copper fingers 931) on the interposer frame and one or more flexes 930 can be bridged by a conductive shape 950 of uniform scale.

[0062] Figure 11 provides a more detailed example of the connection from the interposer frames 925, 1025 to the traces (shown as ground plane 939 in FIG. 9B) on the surface of one or more flex circuits 930, 1030. An adhesive is applied to the conductive shape 1150 of uniform scale, and this shape is placed between the interposer frame and the flex circuit. Specifically, the conductive shape 1150 of uniform scale electrically couples a trace (e.g., Cu finger) 1137 on each flex circuit (not shown in FIG. 11) to a trace (e.g., gold trace) on the interposer frame 1125. Each shape 1150 in this embodiment includes a dielectric material (e.g., glass, polymer) and is uniformly coated with a conductive material (e.g., such as copper, gold, silver, titanium).

[0063] Figures 12-14 illustrate an embodiment of the flexure frame 135 (FIG. 1). FIG. 12 shows an assembly of the flexure frame 1235 and certain elements of the planar linear array described herein, while FIG. 13 exemplifies these portions of the planar linear array after the flex circuit 1330 has been bent using the flexure frame 1335. FIG. 14 shows an enlarged view of the flexure frame 1435. The flexure frames 1235, 1335, 1435 can be attached to the tops of the flex circuits 1230, 1330, 1430. The flexure frames 1235, 1335, 1435 provide a consistent and reliable guide for bending the flex circuits 1230, 1330, 1430 and ensure their adhesion. To show the orientation of the flexure frames 1235, 1335, 1435 within the array (e.g., 100 of FIG. 1), FIGS. 12-14 show elements described in other figures such as the lens layers 1210, 1310, 1410, overmolds 1232, 1332, 1432, interposer frames 1225, 1325, 1425, and flex alignment strips 1233, 1333, 1433. Generally, the flexure frames 1235, 1335, 1435 guide the flex circuits 1230, 1330, 1430 when these flex circuits are bent.

[0064] Returning to FIG. 1, in addition to the flex bending frame 135 that guides the flex circuit 130, in some embodiments of the present invention, when the flex circuit 130 is bent (either individually or by a mechanical process), the backing preform 140 further guides the flex circuit 130. The backing preform 140 is shaped to receive the planar structure of the planar linear array 100. Due to the planar structure of the array embodiments described herein, the structure of the backing preform is simpler and easier to manufacture than the structure of additional embodiments in existing non-planar arrays. By utilizing the backing preform 140 described herein, cost and manufacturing complexity are reduced. As illustrated in and described above with respect to FIG. 1, both the flex bending frame 135 and the interposer frame 125 have cavities 126, 136 (or an opening area having similar or the same coordinates with respect to the width 108 (FIG. 1) and the elevation 101 (FIG. 1)). The backing preform 140 is oriented to extend through the cavities 126, 136. Based on this positioning, the backing preform 140 is in contact with a portion of one or more flex circuits 130.

[0065] The orientation of the backing preform 140 for the backing preform 140 and the planar linear array for the transducer disclosed herein is further illustrated in FIGS. 15 and 16 (1540, 1640). FIG. 15 shows the backing preform 1540 during the assembly of an embodiment of a planar linear array for the transducer disclosed herein, while FIG. 16 shows a view of an embodiment after the assembly of a planar linear array for the transducer disclosed herein to show the relative orientation of the backing preform 1640. Further, both FIGS. 15 and 16 show, as part of the embodiment of the planar linear array shown in both figures, lens layers 1510, 1610, flex alignment strips 1533 as described above herein, and an interposer frame (to which one or more flex circuits 1530, 1630 are attached) utilizing overmolds 1532, 1632. The number of flex circuits 1530, 1630 in FIGS. 15 and 16 is provided by way of example only as in all figures. The number of flex circuits 1530, 1630, as well as the number of flex circuits 1530, 1630 fixed to each flex alignment strip 1533, 1633, may vary. In FIG. 16, the flex circuit 1630 has not yet been bent using the flex bending frames 1535, 1635. Due to the viewing angle of FIG. 16, a piezoelectric layer 1620 directed upward of the lens layer 1610 is included to illustrate the elements of this embodiment of the planar linear array discussed herein and the relative arrangement of these elements with respect to each other.

[0066] In some embodiments of the present invention, to reduce electromagnetic interference (EMI), a layer of conductive material is deposited mechanically or individually on the backing preforms 1540, 1640. For example, to create an EMI shielding element and bridge the return signal to ground, the backing preforms 1540, 1640 can be wrapped with a conductive tape, including but not limited to copper tape. Alternatively, in some embodiments, the layer of conductive material can be deposited across the surface of the backing preform and across the flexure frame. FIG. 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 across the upper surface of the backing preform 1740 and the upper surface of the flexure frame 1735.

[0067] Another element of the planar linear array described herein included in some embodiments is the bend spacer 145 (FIG. 1). The bend spacer 145 helps an individual or machine assembling the planar linear array for the transducer to bend and / or position one or more flex circuits 130 (FIG. 1). The bend spacer 145 (FIG. 1) is positioned above the backing preform 140 (FIG. 1) by an individual or machine such that when one or more flex circuits 130 (FIG. 1) are bent, they are substantially parallel to the axis of the stack thickness 109. Returning to FIG. 9B, when one or more flex circuits 930 are bent, each first portion of the one or more flex circuits 930 remains parallel to the piezoelectric layer along the elevation 101 (FIG. 1), while the second portion of the one or more flex circuits 930 is bent perpendicular to the piezoelectric layer along the elevation 101 (FIG. 1). The portion parallel to the piezoelectric layer along the elevation 101 (FIG. 1) includes copper fingers 931.

[0068] Figures 18 and 19 show examples of planar linear array stacks 1800, 1900 that include bending spacers 1845, 1945 viewed from two different perspectives. Figure 18 provides an orthographic projection view of the planar linear array stack 1800, while Figure 19 provides 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 discussed previously, in certain embodiments of the planar linear array stacks 1800, 1900, one or more matching layers separate the lens layers 1810, 1910 from the piezoelectric layers 1820, 1920. Although not depicted, as discussed previously, the lens layers 1810, 1910 can include both the acoustic lens itself and the lens support structure. Similarly, the piezoelectric layers 1820, 1920 can also include both the piezoelectric material and the support structure or frame structure, and the support or frame structure positions the piezoelectric material on a plane parallel to the acoustic lens in substantially the same orientation along the elevation 101 (Figure 1) and the width 108 (Figure 1). The piezoelectric layers 1820, 1920 can include ground trenches. The interposer frames 1825, 1925, overmolds 1832, 1932, and flex alignment strips 1833, 1933 are combined to secure the flex circuits 1830, 1930. The flex bending frames 1835, 1935 and the backing preforms 1540, 1640 guide the bending of the flex circuits 1830, 1930, while the bending spacers 1845, 1945 function to hold the flex circuits 1830, 1930 in place after they are bent. The flex circuits 1830, 1930 are bent such that a portion of each flex circuit 1830, 1930 is substantially perpendicular to the axis of the width 108 (Figure 1) and another portion is substantially parallel to the width 108 (Figure 1). The bending spacers 1845, 1945 are adjacent to the upper surfaces 1861, 1961 of the backing preforms 1540, 1640, and at least two side surfaces 1862, 1962 substantially surround a portion of these surfaces. Figure 20 depicts an example view of this element alone so that the shape of the bending spacer 2045 can be recognized outside the context of the planar linear array.

[0069] Figures 1-20 show various aspects of some embodiments of a planar linear array that can be integrated within an ultrasonic transducer. Figure 21 shows a workflow 2100 that illustrates various aspects of some methods of manufacturing the planar linear arrays shown in Figures 1-20 and 22 discussed herein. The steps of the process described in workflow 2100 can be achieved individually and / or by automated processes using various machines and manufacturing techniques. The provided steps are examples of aspects of some embodiments of the present invention, and certain examples can combine, omit, and / or add one or more aspects. To manufacture a planar array stack for an ultrasonic transducer as described in Figures 1-20, a piezoelectric layer including a non-metallic frame and a piezoelectric material is formed (2110). To manufacture certain embodiments for forming the piezoelectric layer, the piezoelectric material is assembled with the non-metallic material on at least two sides. The non-metallic material can be fixed to a portion around the piezoelectric material. In some embodiments, to form the piezoelectric layer, one or more ground trenches are further formed within the non-metallic material, filled with a first conductive material (e.g., silver, gold), and coated with a second conductive material (e.g., silver, gold). The first and second materials can be the same material or different materials. In some embodiments of the planar linear array, one or more electrodes are formed on the surface of the piezoelectric material.

[0070] Continuing with the workflow 2100, a lens support structure is formed (2120). The formed device will align the lens to a certain position within the stack, which will be discussed later in this specification with respect to the lens formation workflow. This lens support device is also referred to as the lens support structure (see 212 in FIG. 2 and 312 in FIG. 3). The method of forming this structure will vary depending on the structure of the lens support device (also referred to as the lens support structure) which can be made of ceramic. In some embodiments, the lens support structure includes a first bar 213a and a second bar 213b as shown in FIG. 2, and thus forming the lens support structure includes orienting the first bar and the second bar such that they are located on both sides of the lens 211. In some embodiments, as illustrated in FIG. 3, the lens support structure (lens support structure 312) is a frame, and forming the lens support structure includes orienting this frame around the perimeter of the lens 314. In some embodiments, the lenses within a planar linear array are added after all aspects (shown in FIGS. 1, 18, and 19) except the bending spacers of the planar linear array are formed or positioned. Thus, since the lenses can be formed at various times during the manufacturing process, this workflow 2100 includes forming the lens support device but does not necessarily include forming the lenses.

[0071] In some embodiments, prior to forming the piezoelectric layer, the piezoelectric material can be machined (e.g., laser machined) to include one or more kerfs (see FIG. 5). Thus, prior to forming the piezoelectric layer (2110), one or more kerfs can be formed within the piezoelectric material, for example, by utilizing an excimer laser. The kerf pattern that can be formed can be varied and can include cutting at least one kerf into the piezoelectric material to re-divide the piezoelectric material while maintaining the aspect ratio, and / or cutting a square pattern and / or a parallelogram pattern, but is not limited thereto. Examples of these patterns are illustrated in FIG. 5.

[0072] Returning again to FIG. 21 to continue workflow 2100, one or more matching layers are formed (2140) between the lens layer and the piezoelectric layer. The non-metallic material of the piezoelectric layer is joined (2150) to a spacer frame (e.g., 625 of FIG. 6, 725 of FIG. 7). The spacer frame (including an opening as the frame) is electrically coupled (2160) to one or more flexible circuits (see FIG. 8). These flexible circuits include traces. In some embodiments, an overmold and / or a flexible alignment strip (see FIGS. 6-8) are utilized to fix the flexible circuit to the spacer frame. By orienting a plurality of conductive shapes of a uniform scale on the surface of the spacer frame such that they are in contact with the traces and the spacer frame, the spacer frame is electrically coupled (2170) to the traces. In some embodiments, as shown in FIG. 11, an adhesive is applied to the conductive shape 1150 of the uniform scale, and the conductive shape 1150 of the uniform scale is oriented between the spacer frame and the flexible circuit such that they are electrically coupled to the traces (e.g., Cu fingers) 1137 on each flexible circuit and further electrically coupled to the traces (e.g., gold traces) on the spacer frame 1125. As discussed above, in this embodiment, each conductive shape 1150 of the uniform scale is composed of a dielectric material (e.g., glass, polymer) and uniformly coated with a conductive material (e.g., such as copper, gold, silver, titanium).

[0073] With the flex fixed to the interposer frame and electrical connection established by a conductive pattern of uniform scale, the flex bending frame (having an opening) is oriented substantially parallel to the first portion of the one or more flex circuits such that the second portion of each of the one or more flex circuits extends beyond the outer boundary of the interposer frame. The second portion is to be bent around this outer boundary (2180). FIGS. 12-14 include examples of the orientation of the flex bending frames 1235, 1345, 1435 and these frames within this stack during assembly of the planar linear stack. The bending of the flex circuit is also guided by the backing preform. To enable bending, the backing preform is oriented such that it extends through the openings in the interposer frame and the flex bending frame (see, e.g., FIGS. 14-16) (2190).

[0074] As discussed previously, the lens can be formed at various times within the workflow 2100. On the one hand, the lens can be formed within the lens support structure. Specifically, with the flex circuit attached and the array completed to the point where the array is backed against a structure (e.g., the backing preform) to secure the structure, the lens is inserted into the lens support structure and the rod is rotated to generate the curvature by parallel polishing the surface of the lens to a predetermined depth. Alternatively, the lens can be provided at the time when the lens layer is added to the stack, but the curvature is achieved at a time after the backing preform is attached. Thus, after the preform is attached, the curvature can be added and / or implemented within the lens (2192).

[0075] FIG. 22 shows an example of a technique for forming a lens used in a transducer including an embodiment of the planar linear array stack described herein. The resulting transducer will focus an ultrasonic beam to a predetermined depth in the imaging field of view. The curvature of lens 2216 provides this focusing. To form the curvature of the lens, in this non-limiting example, a portion of planar linear array stack 2200 including only a lens layer 2211, which is an acoustic lens, an interposer frame 2225, one or more flexes 2230, a flex bending frame 2235, and a backing preform 2240 is assembled. The assembly of planar linear array stack 2200 is completed by attaching one or more flexes 2230 and backing this structure with backing preform 2240 (e.g., 2110 - 2910 in FIG. 21). Planar linear array 2200 is positioned within a fixture that orientates acoustic lens 2211 upward (this orientation is opposite the vertical orientation of this element when compared to FIG. 1). By rotating a rod to parallel polish exposed top surface 2217 to a certain depth, curvature 2216 is generated on acoustic lens 2211.

[0076] Returning to FIG. 21, spacers are oriented above the top surface of the backing preform and on a portion of two sides of the backing preform to further enable bending and support the flex circuit after the flex circuit is in a bent position, where the two sides of the backing preform are parallel to the top surface of the backing preform (2194). The flex is bent around the outer boundaries of the flex bending frame and the spacers (2195). The resulting planar linear array can be positioned within a housing for use in an ultrasonic probe.

[0077] The advantages of the embodiments of the linear planar arrays described herein and the manufacturing processes for these embodiments include, but are not limited to, simplifying manufacturing tools, eliminating manufacturing processes that consume long hours, reducing the difficulty of manufacturing, reducing dependence on operator skills, reducing the defect rate, and reducing the cost of reduction. The arrays described herein, when integrated into ultrasonic transducers, provide the advantages listed above without sacrificing yield, and thus provide substantially the same and / or improved compatibility, form, and function when compared to existing systems.

[0078] Embodiments of the present invention include ultrasonic transducers and methods of manufacturing and using the same. In some embodiments, the ultrasonic transducer includes a planar array stack. The planar array stack can include a lens layer that includes an acoustic lens and a lens support structure. A portion of the acoustic lens is fixed to the lens support structure. Further, the planar array stack can include a piezoelectric layer that includes a non-metallic frame and a piezoelectric material, wherein the non-metallic frame surrounds the piezoelectric material on at least two sides, and the non-metallic frame is coupled to a portion of the lens support structure such that the acoustic lens and the non-metallic frame are oriented substantially parallel to each other. The ultrasonic transducer can further include an interposer frame for positioning one or more flexible circuits, wherein the interposer frame is coupled to the non-metallic frame and to one or more flexible circuits through conductive elements within the non-metallic frame. One or more flexible circuits are also included within the ultrasonic transducer.

[0079] In some embodiments of the ultrasonic transducer, one or more flexible circuits and the interposer frame are electrically coupled to a ground electrode.

[0080] In some embodiments of the ultrasonic transducer, the lens support structure includes a first bar and a second bar. The first bar and the second bar are located on both sides of the acoustic lens.

[0081] In some embodiments of the ultrasonic transducer, the lens support structure includes a frame surrounding the rectangular perimeter of the acoustic lens.

[0082] In some embodiments of the ultrasonic transducer, the lens support structure includes ceramic.

[0083] In some embodiments of the ultrasonic transducer, the acoustic lens includes a curvature, and the curvature has a minimum value on a line parallel to the piezoelectric material within the planar array stack.

[0084] In some embodiments of the ultrasonic transducer, the acoustic lens includes a dielectric material.

[0085] In some embodiments of the ultrasonic transducer, the piezoelectric material includes one or more kerfs, and the kerfs include a pattern.

[0086] In some embodiments of the ultrasonic transducer, one or more kerfs include lines that re-divide the dielectric material to maintain an aspect ratio.

[0087] In some embodiments of the ultrasonic transducer, the pattern is selected from the group consisting of a square pattern and a parallelogram pattern.

[0088] In some embodiments of the ultrasonic transducer, the non-metallic frame includes one or more ground trenches.

[0089] In some embodiments of the ultrasonic transducer, at least one of the one or more ground trenches is filled with a first conductive material and coated with a second conductive material based on the filling.

[0090] In some embodiments of the ultrasonic transducer, the non-metallic frame surrounding the piezoelectric material is adhesively bonded to the outer boundary of the piezoelectric material using glue.

[0091] In some embodiments of the ultrasonic transducer, the ultrasonic transducer includes one or more matching layers between the lens layer and the piezoelectric layer.

[0092] In some embodiments of the ultrasonic transducer, the piezoelectric layer includes electrodes on a surface proximate to one or more matching layers.

[0093] In some embodiments of the ultrasonic transducer, the interposer frame is electrically coupled to one or more flex circuits through a plurality of conductive shapes of a uniform scale coated with a conductive material.

[0094] In some embodiments of the ultrasonic transducer, a plurality of conductive shapes of a uniform scale conduct an electrical signal from a surface of the interposer frame in contact with these conductive shapes to a trace on a surface of one or more flex circuits in contact with these conductive shapes.

[0095] In some embodiments of the ultrasonic transducer, each conductive shape of a uniform scale of the plurality of conductive shapes of a uniform scale is composed of a dielectric material.

[0096] In some embodiments of the ultrasonic transducer, each conductive shape of a uniform scale of the plurality of conductive shapes of a uniform scale is coated with a conductive material.

[0097] In some embodiments of the ultrasonic transducer, the surface of the interposer frame in contact with the plurality of conductive shapes of a uniform scale includes one or more conductive traces.

[0098] In some embodiments of the ultrasonic transducer, the electrical connection through the plurality of conductive shapes of a uniform scale coated with a conductive material forms a vertical electrical connection between the interposer frame and one or more conductive traces oriented on a parallel plane.

[0099] In some embodiments of the ultrasonic transducer, the ultrasonic transducer includes the above frame in which a second portion of each of the one or more flex circuits is bent substantially perpendicular to a surface of the frame perpendicular to the planar array stack and is positioned substantially parallel to a first portion of the one or more flex circuits such that the frame and the lens layer are on a parallel horizontal plane.

[0100] In some embodiments of the ultrasonic transducer, the ultrasonic transducer includes one or more flex alignment strips. Each flex alignment strip is positioned between the interposer frame and a frame positioned substantially parallel to a first portion of one or more flex circuits.

[0101] In some embodiments of the ultrasonic transducer, each flex circuit of one or more flex circuits is attached to a flex alignment strip of the one or more flex alignment strips.

[0102] In some embodiments of the ultrasonic transducer, the frame positioned substantially parallel to a first portion of one or more flex circuits includes a first cavity, and the interposer frame includes a second cavity. In this embodiment, the ultrasonic transducer further includes a backing preform that extends through the first cavity and the second cavity and contacts a portion of one or more flex circuits.

[0103] In some embodiments of the ultrasonic transducer, the backing preform is coated with a conductive tape.

[0104] In some embodiments of the ultrasonic transducer, the transducer includes a bend spacer. The bend spacer is positioned above the backing preform such that a second portion of each flex circuit of one or more flex circuits is substantially parallel to the surface of the bend spacer that is perpendicular to the planar array stack.

[0105] In some embodiments of the ultrasonic transducer, the non-metallic frame positions the piezoelectric material at a central position with respect to the elevation and width of the planar array stack.

[0106] In some embodiments of the ultrasonic transducer, the transducer includes an overmold that fixes one or more flex circuits to the interposer frame.

[0107] In some embodiments of the ultrasonic transducer, the overmold includes electrodes on at least one surface.

[0108] In some embodiments of the ultrasonic transducer, the ultrasonic transducer includes a lens layer including a lens, one or more matching layers between the lens layer and the piezoelectric layer, and a piezoelectric layer including a non-metallic frame and a piezoelectric material, wherein the non-metallic frame surrounds the piezoelectric material on at least two sides, and the ultrasonic transducer includes a planar array stack including the piezoelectric layer. Further, the transducer can include an interposer frame for positioning one or more flex circuits. The interposer frame is coupled to the non-metallic frame and to one or more flex circuits through conductive elements within the non-metallic frame. The transducer further includes one or more flex circuits.

[0109] In some embodiments of the ultrasonic transducer, the ultrasonic transducer includes a lens layer including a lens, and a piezoelectric layer including a non-metallic frame and a piezoelectric material, wherein the non-metallic frame surrounds the piezoelectric material on at least two sides and is coupled to a portion of the lens layer, and the ultrasonic transducer includes a planar array stack including the piezoelectric layer. The transducer can further include an interposer frame for positioning one or more flex circuits, the interposer frame being coupled to the non-metallic frame and to one or more flex circuits through conductive elements within the non-metallic frame. Further, the transducer can include one or more flex circuits.

[0110] In some embodiments of a method of manufacturing a planar array stack for an ultrasonic transducer, the method includes forming a piezoelectric layer including a non-metallic material and a piezoelectric material, the forming including assembling the piezoelectric material with the non-metallic material on at least two sides. The method can also include forming a lens support structure that orients an acoustic lens to a central position with respect to the width and elevation of the planar array stack. The method can also include adhering the lens support structure to the piezoelectric layer such that the lens support structure and the piezoelectric layer are parallel with respect to the width and elevation.

[0111] In some embodiments of the method, the lens support structure includes a first bar and a second bar, and forming the lens support structure includes orienting the first bar and the second bar on both sides of the lens.

[0112] In some embodiments of the method, the lens support structure includes a frame, and forming the lens support structure includes orienting the frame around the lens.

[0113] In some embodiments of the method, the lens support structure includes ceramic.

[0114] In some embodiments of the method, the method includes forming one or more kerfs in the piezoelectric material.

[0115] In some embodiments of the method, forming one or more kerfs includes cutting at least one kerf into the piezoelectric material to re-divide the piezoelectric material while maintaining the aspect ratio.

[0116] In some embodiments of the method, forming one or more kerfs includes cutting a pattern of kerfs into the piezoelectric material.

[0117] In some embodiments of the method, the pattern is selected from the group consisting of a square pattern and a parallelogram pattern.

[0118] In some embodiments of the method, the method includes forming one or more ground trenches in the non-metallic material.

[0119] In some embodiments of the method, the method includes filling one or more ground trenches with a first conductive material. The method may also include coating one or more ground trenches with a second conductive material.

[0120] In some embodiments of the method, forming the piezoelectric layer further includes fixing the non-metallic material to a portion around the piezoelectric material.

[0121] In some embodiments of the method, the method includes forming one or more matching layers between the lens layer and the piezoelectric layer.

[0122] In some embodiments of the method, forming the piezoelectric layer further includes forming one or more electrodes on the surface of the piezoelectric material.

[0123] In some embodiments of the method, the method includes bonding the non-metallic material of the piezoelectric layer to the spacer frame.

[0124] In some embodiments of the method, the method includes electrically coupling the spacer frame to one or more flexible circuits, wherein the surface of each of the one or more flexible circuits includes traces, the spacer frame includes a first opening, and electrically coupling includes fixing one or more flexible circuits to the spacer frame using overmolding, and the surface of the overmolding includes one or more electrodes.

[0125] In some embodiments of the method, electrically coupling includes directing a plurality of conductive shapes of a uniform scale onto the surface of the spacer frame. The method can further include electrically coupling the spacer frame to the traces by coupling the traces to a plurality of conductive shapes of a uniform scale.

[0126] In some embodiments of the method, each conductive shape of the plurality of conductive shapes of a uniform scale includes a dielectric material coated with a conductive material.

[0127] In some embodiments of the method, the method includes orienting a flexible bending frame including a second opening substantially parallel to a first portion of one or more flexible circuits such that a second portion of each of the one or more flexible circuits extends beyond the outer boundary of the spacer frame.

[0128] In some embodiments of the method, electrically coupling the spacer frame to one or more flex circuits includes fixing each of the one or more flex circuits to an alignment strip of a plurality of alignment strips and orienting each of the plurality of alignment strips to be positioned between the spacer frame and the flex bending frame.

[0129] In some embodiments of the method, the method includes orienting a backing preform in a direction such that it contacts a given portion of one or more flexes based on it extending through a first opening and a second opening.

[0130] In some embodiments of the method, the method includes forming a lens within a lens support structure.

[0131] In some embodiments of the method, the method includes bending a second portion of each flex circuit of one or more flex circuits to be oriented substantially perpendicular to the surface of the flex bending frame.

[0132] In some embodiments of the method, the method includes orienting spacers above the upper surface of the backing preform and on a portion of two sides of the backing preform parallel to this upper surface.

[0133] In some embodiments of the method, the method includes depositing a copper shield on the upper surface of the backing preform.

[0134] In some embodiments of the method, the method includes using a non-metallic material to position a piezoelectric material at a central position with respect to elevation and width within a planar array stack.

[0135] 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 the flowchart or block diagram can represent a module, segment, or portion of instructions that include one or more executable instructions for implementing a defined logical function. In some alternative implementations, the functions represented by the blocks can be performed using an order different from that shown in the figures. For example, two blocks shown in succession can actually be performed substantially simultaneously, or can sometimes be performed in the reverse order depending on the functions involved. It should also be noted that each block and combination of blocks in the exemplary block diagrams and / or flowcharts can be implemented by a system based on dedicated hardware that performs the defined function or acts as a combination of dedicated hardware and computer instructions or implements it.

[0136] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an", and "the" are intended to include the plural referents as well, unless the context clearly indicates otherwise. As used herein, "comprising" and / or "comprises" specify the presence of the features, integers, steps, operations, elements, and / or components described, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0137] In the case where any of all the means or steps in the following claims, and corresponding structures, materials, acts, and equivalents of functional elements exist, they are intended to include any structure, material, or act for implementing the function in combination with other claimed elements specifically claimed. For purposes of illustration and description, descriptions of one or more embodiments have been provided, but these descriptions are not intended to be comprehensive or to limit the disclosed forms. Many modifications and changes will be apparent to those skilled in the art. The embodiments were selected and described with the aim of most clearly explaining various aspects and practical applications, and enabling those skilled in the art to understand various embodiments having various modifications suitable for specific applications contemplated.

Description of Reference Numerals

[0138] 100 Planar array stack for ultrasonic transducer 101 Elevation of planar array stack 110 Lens layer 120 Piezoelectric layer 125 Interposer frame 130 Flexible circuit

Claims

1. An ultrasonic transducer, comprising: a lens layer including an acoustic lens and a lens support structure, wherein a portion of the acoustic lens is fixed to the lens support structure; and a piezoelectric layer including a non-metallic frame and a piezoelectric material, wherein the non-metallic frame surrounds the piezoelectric material on at least two sides, and the non-metallic frame is coupled to a portion of the lens support structure such that the acoustic lens and the non-metallic frame are substantially parallel to each other; a planar array stack including the above; an interposer frame for positioning one or more flexible circuits, the interposer frame being coupled to the non-metallic frame and the one or more flexible circuits through conductive elements within the non-metallic frame; the one or more flexible circuits; An ultrasonic transducer comprising the above.

2. The ultrasonic transducer according to claim 1, wherein the one or more flexible circuits and the interposer frame are electrically coupled to a ground electrode.

3. The lens support structure includes a first bar and a second bar, wherein the first bar and the second bar are located on both sides of the acoustic lens. The ultrasonic transducer according to claim 1.

4. The ultrasonic transducer according to claim 1, wherein the lens support structure includes a frame surrounding a rectangular perimeter of the acoustic lens.

5. The ultrasonic transducer according to claim 1, wherein the lens support structure includes ceramic.

6. The acoustic lens includes curvature, wherein the curvature has a minimum value on a line parallel to the piezoelectric material within the planar array stack. The ultrasonic transducer according to claim 1.

7. The ultrasonic transducer according to claim 1, wherein the acoustic lens includes a dielectric material.

8. The piezoelectric material includes one or more kerfs, wherein the kerfs include a pattern. The ultrasonic transducer according to claim 1.

9. The ultrasonic transducer according to claim 8, wherein the one or more kerfs include lines that re-divide the dielectric material to maintain an aspect ratio.

10. The ultrasonic transducer according to claim 8, wherein the pattern is selected from the group consisting of a square pattern and a parallelogram pattern.

11. The ultrasonic transducer according to claim 1, wherein the non-metallic frame includes one or more ground trenches.

12. The ultrasonic transducer according to claim 11, wherein at least one of the one or more grounding trenches is filled with a first conductive material and coated with a second conductive material based on the filling.

13. The ultrasonic transducer according to claim 1, wherein the non-metallic frame surrounding the piezoelectric material is adhered to the outer boundary of the piezoelectric material using an adhesive.

14. The ultrasonic transducer according to claim 1, further comprising one or more matching layers between the lens layer and the piezoelectric layer.

15. The ultrasonic transducer according to claim 15, wherein the piezoelectric layer includes an electrode on a surface proximate to the one or more matching layers.

16. The ultrasonic transducer according to claim 1, wherein the intervening frame is electrically coupled to the one or more flexible circuits through a plurality of conductive shapes of a uniform scale coated with a conductive material.

17. The ultrasonic transducer according to claim 16, wherein the plurality of conductive shapes of the uniform scale conduct an electrical signal from a surface of the intervening frame in contact with the plurality of conductive shapes of the uniform scale to a trace on a surface of the one or more flexible circuits in contact with the plurality of conductive shapes of the uniform scale.

18. The ultrasonic transducer according to claim 16, wherein each conductive shape of the plurality of conductive shapes of the uniform scale is composed of a dielectric material.

19. The ultrasonic transducer according to claim 16, wherein each conductive shape of the plurality of conductive shapes of the uniform scale is coated with the conductive material.

20. The ultrasonic transducer according to claim 17, wherein the surface of the intervening frame in contact with the plurality of conductive shapes of the uniform scale includes one or more conductive traces.

21. The ultrasonic transducer according to claim 16, wherein the electrical connection through the plurality of conductive shapes of the uniform scale coated with the conductive material forms a vertical electrical connection between the intervening frame and the one or more conductive traces oriented on a parallel plane.

22. The frame, wherein a second portion of each of the one or more flexible circuits is bent substantially perpendicular to a surface of a frame perpendicular to the planar array stack, such that the frame and the lens layer are positioned substantially parallel to each other on a horizontal plane, and the frame is positioned substantially parallel to a first portion of the one or more flexible circuits. The ultrasonic transducer according to claim 1, further comprising. Claim 23 One or more flex alignment strips positioned between the spacer frame and a frame positioned substantially parallel to a first portion of the one or more flex circuits, each flex alignment strip being one of the one or more flex alignment strips so positioned. The ultrasonic transducer according to claim 22, further comprising. Claim 24 The ultrasonic transducer according to claim 23, wherein each flex circuit of the one or more flex circuits is attached to a flex alignment strip of the one or more flex alignment strips. Claim 25 The frame positioned substantially parallel to the first portion of the one or more flex circuits includes a first cavity, and the spacer frame includes a second cavity. The ultrasonic transducer is A backing preform extending through the first cavity and the second cavity and contacting a portion of the one or more flex circuits. further comprising The ultrasonic transducer according to claim 22. Claim 26 The ultrasonic transducer according to claim 25, wherein the backing preform is coated with a conductive tape. Claim 27 A bending spacer, wherein the second portion of each flex circuit of the one or more flex circuits is positioned above the backing preform such that it is substantially parallel to a surface of the bending spacer perpendicular to the planar array stack. The ultrasonic transducer according to claim 25, further comprising. Claim 28 The ultrasonic transducer according to claim 1, wherein the non-metallic frame positions the piezoelectric material at a central position with respect to the elevation and width of the planar array stack. Claim 29 An overmold for fixing the one or more flex circuits to the spacer frame. The ultrasonic transducer according to claim 1, further comprising. Claim 30 The ultrasonic transducer according to claim 29, wherein the overmold includes electrodes on at least one surface. Claim 31 An ultrasonic transducer comprising A lens layer including a lens, One or more matching layers between the lens layer and the piezoelectric layer, and The piezoelectric layer including a non-metallic frame and a piezoelectric material, the non-metallic frame surrounding the piezoelectric material on at least two sides. A planar array stack including, An interposer frame for positioning one or more flexible circuits, the interposer frame being coupled to the non-metallic frame and the one or more flexible circuits through conductive elements within the non-metallic frame the one or more flexible circuits An ultrasonic transducer comprising Claim 32 An ultrasonic transducer comprising a lens layer including a lens, and a piezoelectric layer including a non-metallic frame and a piezoelectric material, the non-metallic frame surrounding the piezoelectric material on at least two sides, the non-metallic frame being coupled to a portion of the lens layer a planar array stack including An interposer frame for positioning one or more flexible circuits, the interposer frame being coupled to the non-metallic frame and the one or more flexible circuits through conductive elements within the non-metallic frame the one or more flexible circuits An ultrasonic transducer comprising

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