4D ultrasound catheter

Abstract

The application relates to a 4D ultrasonic catheter. The 4D ultrasonic catheter comprises a catheter body, a plurality of transducer array elements arranged inside the distal end of the catheter body, a control chip and a flexible circuit board; the plurality of transducer array elements are arranged in a matrix; the control chip comprises a non-wire bonding area and a wire bonding area, the non-wire bonding area is provided with a plurality of central pads, the plurality of central pads are connected with the plurality of transducer array elements one by one through solder or direct bonding connection, the wire bonding area is provided with a plurality of IO pads, the signal pad types of the plurality of IO pads are divided into digital signal pads, analog signal pads, power supply pads and ground pads; the flexible circuit board comprises a plurality of functional layers, any functional layer is provided with a plurality of signal lines and a plurality of connection pads, the connection pads are connected with the IO pads through wire bonding, and the signal types of the signal lines are divided into digital signal lines, analog signal lines, power supply signal lines or ground signal lines.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a 4D ultrasound catheter. Background Technology

[0002] With the rapid development of medical and electronic technologies, ultrasound catheters have emerged. As people's requirements for ultrasound images have gradually increased, 4D ultrasound catheters have further developed based on 2D ultrasound catheters. 4D ultrasound catheters expand the one-dimensional ultrasound transducer array from one dimension to two dimensions. Therefore, based on the thousands of high-frequency, tiny transducer array elements included in the 4D ultrasound catheter, the 4D ultrasound catheter can realize high-resolution three-dimensional (4D) imaging of the human body in real time and accurately.

[0003] Since 2D ultrasonic catheters only require single-type signal extraction of multiple analog signals, which can be achieved using a thermoforming process, their design cannot cover the high-density digital signal, power signal, and ground signal extraction requirements of 4D ultrasonic catheters. Therefore, existing designs cannot be used. Furthermore, the high-density signal extraction of 4D ultrasonic catheters also needs to consider design requirements for miniaturization, signal stability, and signal reliability. Although indirect connection between the transducer array elements and the control chip can achieve multi-type signal extraction, it easily introduces additional parasitic inductance and capacitance, degrading the transmission quality of high-frequency ultrasonic signals and affecting imaging results. Additionally, indirect connection can easily reduce the number of ports and sacrifice the catheter's anti-interference capability due to space constraints. Summary of the Invention

[0004] Based on this, the present application aims to solve at least one technical problem existing in the background art and provide a 4D ultrasound catheter.

[0005] This application provides a 4D ultrasonic catheter, including a catheter body and multiple transducer elements, a control chip, and a flexible circuit board disposed inside the distal end of the catheter body. The multiple transducer elements are arranged in a matrix. The control chip includes a non-wire-bonded region and a wire-bonded region. The non-wire-bonded region has multiple central pads, which are connected to the multiple transducer elements one-to-one by solder or direct bonding. The wire-bonded region has multiple I / O pads, and the signal pad types of the multiple I / O pads are divided into digital signal pads, analog signal pads, power pads, and ground pads. The flexible circuit board includes multiple functional layers, each of which is provided with several signal lines and multiple connection pads. The connection pads are connected to the I / O pads by wire bonding. The signal types of the signal lines are divided into digital signal lines, analog signal lines, power signal lines, or ground signal lines. The flexible circuit board, the control chip, and the multiple transducer elements are connected sequentially to excite the transducer elements to emit ultrasonic signals and to feed back processed echo electrical signals.

[0006] The aforementioned ultrasonic catheter has a control chip with both a non-wire bonding region and a wire bonding region. The non-wire bonding region has multiple central pads for connecting multiple transducer elements. Based on this, the multiple transducer elements can be vertically bonded to the surface of the control chip, achieving a direct connection between the multiple transducer elements and the control chip. Since the ultrasonic catheter provided in this embodiment does not require indirect connection between the multiple transducer elements and the control chip through an interposer, firstly, no additional parasitic inductance or capacitance is introduced between the multiple transducer elements and the control chip, thereby greatly optimizing the transmission path of the high-frequency ultrasonic signal and significantly improving the transmission quality of the high-frequency ultrasonic signal. Secondly, the size of the transducer elements and the spacing between the multiple transducer elements can be completely determined by the acoustic design requirements of the ultrasonic catheter, eliminating the limitations of the interposer's via dimensions. Furthermore, this allows for further miniaturization of the transducer elements, providing a necessary foundation for improving the imaging resolution of the ultrasonic catheter. Furthermore, the connection pads and I / O pads are connected via wire bonding. On one hand, wire bonding allows the flexible circuit board and the chip to be positioned with a certain axial offset rather than a conventional vertical stacking relationship, which is beneficial for miniaturizing the radial dimension of the distal end of the conduit. On the other hand, wire bonding can adapt to design backgrounds where I / O pads of various types of signals are dispersed. Even if multiple different types of I / O pads are not bonded to the connection pads in a specific order, a precise connection relationship between multiple types of pads can be established through flexible wire bonding, without the need for complex via paths on an interposer. Therefore, this application as a whole effectively balances the functional requirements of multiple types of high-density signal extraction with the design requirements of space miniaturization, signal stability, and signal reliability. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a schematic diagram of the structure of a 4D ultrasound catheter provided in an embodiment of this application;

[0009] Figure 2 This is a schematic diagram of another 4D ultrasound catheter provided in an embodiment of this application;

[0010] Figure 3 for Figure 2 The embodiment provides a schematic diagram of the distal end structure of the catheter assembled in the catheter body;

[0011] Figure 4 A schematic diagram of the structure of a 4D ultrasonic catheter from a top-down view, provided as an embodiment of this application;

[0012] Figure 5 for Figure 4 A schematic diagram of the 4D ultrasound catheter in the embodiment from the main viewpoint. Detailed Implementation

[0013] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0015] It is understood that the terms "first," "second," etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, both the first flexible circuit board and the second flexible circuit board are flexible circuit boards, and the unconnected portions of the first flexible circuit board and the second flexible circuit board should be understood to have circuits that are independent of each other.

[0016] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0017] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0018] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0019] As described in the background section, 4D ultrasound catheters comprise thousands of high-frequency, tiny transducer elements. At this scale and order of magnitude, achieving high-density, high-reliability connections between the transducer array (containing multiple transducer elements) and the control chip is a major technological challenge. Currently, the industry standard solution is to use a rigid substrate (exemplarily a silicon substrate or glass substrate) manufactured using precision semiconductor processes as an intermediary. Existing technologies place the control chip and transducer array on opposite sides of the rigid substrate and connect them via micro-wiring within the substrate. While this standard solution can improve wiring density to some extent, limitations inherent in the rigid substrate manufacturing process—such as via size, aspect ratio, and layer count—often force ultrasound catheter designers to sacrifice optimal acoustic dimensions of the transducer elements to meet connection feasibility requirements. This can negatively impact the imaging resolution of the ultrasound catheter.

[0020] Clearly, conventional solutions cannot meet the stringent requirements of signal and power integrity in the connection between the thousands of high-frequency, miniature transducer elements in a 4D ultrasonic catheter and the control chip. Furthermore, the minimum size of the vias in the rigid substrate, which serves as the intermediary, directly limits the spacing of the transducer element pads, hindering further miniaturization and negatively impacting the imaging resolution of the 4D ultrasonic catheter. Additionally, the indirect connection between the transducer elements and the control chip via the intermediary introduces extra parasitic inductance and capacitance, further degrading the transmission quality of high-frequency ultrasonic signals. Therefore, it is necessary to provide a 4D ultrasonic catheter where multiple transducer elements are indirectly connected to the control chip without relying on an intermediary substrate, thus better balancing the functional requirements of extracting multiple types of high-density signals with the design requirements of spatial miniaturization, signal stability, and signal reliability.

[0021] Based on this, such as Figure 1 As shown, this application provides a 4D ultrasonic catheter, including a catheter body and multiple transducer array elements 102, a control chip 104, and a flexible circuit board 106 disposed inside the distal end of the catheter body; the multiple transducer array elements 102 are arranged in a matrix; the surface of the control chip 104 is provided with a non-wire bonding region 1 and a wire bonding region 2, the non-wire bonding region 1 is provided with multiple central pads, and the multiple central pads are connected to the multiple transducer array elements 102 one-to-one by solder or direct bonding, the wire bonding region 2 is provided with multiple IO pads 1042, and the multiple IO pads 1042 are connected to the transducer array elements 102 by solder or direct bonding. The signal pads of 042 are classified into digital signal pads, analog signal pads, power pads, and ground pads. The flexible circuit board 106 includes multiple functional layers. Each functional layer is provided with several signal lines and multiple connection pads 1062. The connection pads 1062 and IO pads 1042 are connected by wire bonding. The signal types of the signal lines are classified into digital signal lines, analog signal lines, power signal lines, or ground signal lines. The flexible circuit board 106, the control chip 104, and multiple transducer elements 102 are connected in sequence to excite the transducer elements 102 to emit ultrasonic signals and feed back processed echo signals.

[0022] The connection pad 1062 is connected to an external host via a signal line. Signals from the external host are transmitted sequentially via the signal line, connection pad 1062, and I / O pad 1042 to the control chip 104. The control chip 104 receives control signals from the external host, outputs a drive signal via a central pad to drive the transducer element 102 to emit ultrasonic signals, converts the ultrasonic signals received by the transducer element 102 into electrical signals, and then sends them via the central pad to the control chip 104 for processing before outputting them to the external host. It should be noted that the analog and digital signals of the control chip 104 in this application are dynamically changing, as the imaging algorithm performs time-division and zone-division excitation and acquisition on different elements.

[0023] Transducer element 102 refers to the core acoustic functional unit in the 4D ultrasonic catheter, which can be used to achieve bidirectional energy conversion between electrical and mechanical energy based on the piezoelectric effect. Among the multiple transducer elements 102, each transducer element 102 can be independently addressed. That is, the control chip 104 can individually select and control any one transducer element 102 to operate through different methods such as address encoding or channel selection, so as to drive a single transducer element 102 to independently emit ultrasonic signals without affecting the operating status of other transducer elements 102. Based on this, since the multiple transducer elements 102 have high flexibility in image data sampling, the 4D ultrasonic catheter provided in this embodiment has high image data sampling accuracy.

[0024] Optionally, each transducer element 102 is connected to each central pad via any of the following methods: direct contact, anisotropic conductive film, or anisotropic conductive adhesive.

[0025] Optionally, the transducer array element 102 includes an upper electrode and a lower electrode. The lower electrode is connected to the control chip 104 through a central pad. The upper electrode can be grounded by connecting to an exposed pad connected to the control chip 104 or by connecting to a flexible circuit board 106.

[0026] Optionally, the multiple transducer elements 102 connected to the multiple central pads on the first surface of the control chip 104 can be fabricated using an efficient post-integration dicing process: First, an acoustic stacked structure including a piezoelectric material layer, an acoustic matching layer, and a backing layer is integrally bonded and electrically connected to the multiple central pads of the control chip 104 through any of the following methods: direct contact, anisotropic conductive film, or anisotropic conductive adhesive. Then, the acoustic stacked structure is precisely diced along a preset dicing path to form multiple independent transducer elements 102 corresponding one-to-one with the multiple central pads of the control chip 104. Based on this post-integration dicing process, the transducer element 102 can also be understood as multiple independent acoustic functional units formed by mesh-like dicing of the acoustic stacked structure, with the multiple independent acoustic functional units arranged in a matrix.

[0027] It can be seen that this integrated cutting process can reduce the alignment accuracy requirements between the control chip 104 and the multiple transducer array elements 102, and can realize the direct connection between the control chip 104 and the multiple transducer array elements 102, so that no intermediate circuit board is required between the control chip 104 and the multiple transducer array elements 102 in the 4D ultrasonic catheter.

[0028] Since multiple transducer array elements 102 are obtained by cutting the acoustic stacked structure along a preset cutting path, multiple transducer array elements 102 are arranged in a multi-row, multi-column arrangement on the non-wire bonding region 1 of the surface of the control chip 104. Based on this, multiple transducer array elements 102 can be understood as a two-dimensional transducer array.

[0029] The control chip 104 is the core signal processing unit in the 4D ultrasound catheter. It can generate high-frequency ultrasound signals to drive multiple transducer array elements 102, and can filter, amplify, digitize, and beamform the electrical signals returned by the transducer array elements 102.

[0030] The flexible circuit board 106 refers to the carrier in the 4D ultrasonic conduit used to realize the transmission of electrical signals between multiple transducer array elements 102, control chip 104, and external host. The flexible circuit board 106 has the characteristics of bendability and anti-interference capability.

[0031] IO stands for In / Out. Connection pad 1062 refers to the interconnect interface located on the flexible circuit board 106 and connected to the control chip 104. External host refers to the host computer used to provide power and control signals for the operation of the 4D ultrasound catheter, and to process the imaging data from the 4D ultrasound catheter to obtain ultrasound images. Optionally, the external host can be an imaging device. Non-wire bonded region 1 is the core functional area located at the center of the first surface of the control chip 104, used for bidirectional energy conversion between electrical and mechanical energy. Wire bonded region 2 is the outer peripheral area located at least part of the outer periphery of the surface of the control chip 104, used to establish the connection between the control chip 104 and the flexible circuit board 106. Central pad refers to the interconnect node located within the non-wire bonded region 1 of the control chip 104, used to establish a direct connection between multiple transducer array elements 102 and the control chip 104. The arrangement of the multiple central pads is the same as the arrangement of the multiple transducer elements 102. That is, when the multiple transducer elements 102 are arranged in multiple rows and columns, the multiple central pads are also arranged in the same multiple rows and columns. The multiple central pads can be understood as a high-density pad array, and the spacing between each central pad can be adjusted between tens of micrometers and hundreds of micrometers according to the acoustic design requirements. The IO pads 1042 refer to the interconnect interfaces located on the surface of the control chip 104 and directly connected to the flexible circuit board 106. The bonding connection between the IO pads 1042 and the connecting pads 1062 of the flexible circuit board 106 means that the connection between the IO pads 1042 and the connecting pads 1062 is achieved through metal bonding leads 108. In other words, the IO pad 1042 and the connecting pad 1062 are connected point-to-point electrically. This fine wire bonding process is suitable for achieving electrical interconnection of multiple types of high-density signals within the confined space of the 4D ultrasonic catheter provided in this embodiment. The metal bonding lead 108 is an extremely thin metal lead, which can be gold wire, aluminum wire, or other metal lead, as long as it can achieve the connection between the connecting pad 1062 and the IO pad 1042. The bonding connection between the IO pad 1042 and the connecting pad 1062 of the flexible circuit board 106 means that the IO pad 1042 and the connecting pad 1062 are connected through the metal bonding lead 108. That is to say, the IO pad 1042 and the connecting pad 1062 are connected point-to-point electrically. This fine wire bonding process is suitable for achieving electrical interconnection of multiple types of high-density signals within the confined space of the 4D ultrasonic catheter provided in this embodiment. The metal bonding wire 108 is an extremely thin metal wire.Optionally, the metal bonding lead 108 can be gold wire, aluminum wire, or other metal lead, as long as it can achieve the connection relationship between the bonding pad 1062 and the IO pad 1042. The digital signal pad refers to the IO pad 1042 used to connect digital signal lines. Correspondingly, the analog signal pad refers to the IO pad 1042 used to connect analog signal lines; the power pad refers to the IO pad 1042 used to connect power signal lines; and the ground pad refers to the IO pad 1042 used to connect ground signal lines. A digital signal line refers to a signal line used to transmit digital signals. Correspondingly, an analog signal line refers to a signal line used to transmit analog signals; a power signal line refers to a signal line used to transmit power signals; and a ground signal line refers to a signal line used to transmit ground signals.

[0032] Preferably, the connection pads 1062 and IO pads 1042 of the flexible circuit board 106 adopt a one-to-one mapping relationship, but the connection pads 1062 and IO pads 1042 do not follow a specific order. That is, the wire bonding relationship established between a connection pad 1062 and an IO pad 1042 is not affected by the wire bonding relationship of another adjacent connection pad 1062.

[0033] In a straightforward manner, the size of the wire bonding region 2 is determined by the size of the location where the connection relationship needs to be established between the control chip 104 and the flexible circuit board 106.

[0034] The spacing between the multiple IO pads 1042 follows the conventional design rules of wire bonding to facilitate the connection between the IO pads 1042 and the flexible circuit board 106.

[0035] Optionally, the signals from the external host may include power signals, control signals for each of the multiple transducer array elements 102, and parameter configuration signals for the image data sampling process. When the multiple transducer array elements 102 can be independently addressed, power signals will be provided to multiple transducer array elements 102 simultaneously. To control which transducer array elements 102 are in operation, control signals need to be provided to different transducer array elements 102 at different times.

[0036] In conventional ultrasonic catheters, an inflexible rigid substrate is typically used. This rigid substrate is inflexible, and the connection area between the substrate and multiple transducer elements is already densely packed with vias. This forces the I / O pads for connecting to external hosts to be concentrated on a single side of the rigid substrate's wire bonding area (region 2), significantly increasing the difficulty and density of I / O fan-out routing. Furthermore, the number of I / O pins that can be brought out is severely limited by the via size and number of layers on the rigid substrate. Typically, to meet physical fan-out requirements, ultrasonic catheter designers are often forced to adopt performance degradation strategies, such as changing differential signals to single-ended signals with weaker anti-interference capabilities to reduce necessary control and feedback pins, or even compressing the number of ultrasonic analog signal channels. However, these compromises directly reduce the stability and anti-interference capability of the control chip during operation, ultimately impairing the signal-to-noise ratio and imaging quality of the sampled image data. Therefore, how to further free up routing space on the I / O pads of the control chip is also a challenge faced by ultrasonic catheter designers.

[0037] In one exemplary embodiment, such as Figure 1 As shown, the functional layers are stacked along a direction perpendicular to the axial direction of the conduit. The axial spacing between the connection pads 1062 and the wire bonding region 2 of different functional layers is different, so that each connection pad 1062 is exposed layer by layer. At least two adjacent IO pads 1042 are respectively connected to the connection pads 1062 of different functional layers through wire bonding. The multiple functional layers can be multiple independent functional layers, such as being formed by stacking independent functional layers layer by layer, or they can be an integral multilayer structure formed by folding a single metal plate and insulating material.

[0038] In the case where multiple functional layers are formed by folding a single metal plate into a single multi-layer structure, the multiple functional layers are actually a single structure. Each functional layer has a physical connection but is electrically insulated from the others, and the conductive components of each functional layer are the same.

[0039] The axial spacing between the connection pads 1062 and the wire bonding region 2 of different functional layers is different, which means that the different functional layers are of unequal length in the axial direction of the conduit.

[0040] The interconnecting pads 1062 are exposed layer by layer, meaning that the interconnecting pads 1062 of each functional layer are not obscured by the adjacent functional layers; that is, the interconnecting pads 1062 of each functional layer are staggered. The multiple IO pads 1042 of the 4D ultrasonic conduit can be presented in an arrangement of at least one column.

[0041] Since at least two adjacent IO pads 1042 are bonded to connection pads 1062 of different functional layers respectively, a multi-column fan-out connection between multiple IO pads 1042 on the control chip 104 and the flexible circuit board 106 is realized. The multi-column fan-out means that for multiple IO pads 1042 arranged in a column, they can be fanned out to multiple connection pads 1062 of at least two functional layers to achieve bonding connection with the connection pads 1062.

[0042] Optionally, since at least two adjacent IO pads 1042 are bonded to connection pads 1062 of different functional layers respectively, a row of IO pads 1042 can be fanned out to multiple connection pads 1062 of two functional layers, or to connection pads 1062 of three or more functional layers. This can be determined according to the actual needs of the acoustic design, and this application does not limit it here.

[0043] Optionally, the plurality of IO pads 1042 on the control chip 104 and the plurality of connection pads 1062 of the plurality of functional layers on the flexible circuit board 106 can be asymmetrically arranged.

[0044] In this embodiment, since the functional layers are stacked along a direction perpendicular to the axial direction of the conduit, and each connection pad 1062 is exposed layer by layer, firstly, the flexible circuit board 106 can include more functional layers, which can further provide independent and complete reference planes and ample wiring space for the digital signals, analog signals, power signals, or ground signals necessary for the normal operation of the 4D ultrasound conduit, thereby fundamentally ensuring the signal integrity and power integrity of the 4D ultrasound conduit; secondly, it can provide ample layout space for the connection pads 1062, so that the multiple IO pads 1042 of the wire bonding area region 2 of the control chip 104 can adopt a multi-column fan-out design to achieve connection with multiple connection pads 1062. The connection between 62 allows for a further relaxation of the alignment tolerance of the wire bonding process, reducing the manufacturing difficulty of the 4D ultrasonic catheter. Furthermore, it ensures a high degree of layout freedom for the wire bonding process along the direction from the control chip 104 to the flexible circuit board 106. Compared to traditional hot-pressing processes, the wire bonding process used in this embodiment allows the connection pads 1062 and IO pads 1042 that achieve the bonding connection to be arranged without rigid constraints. The IO pads 1042 located in the chip wire bonding region 2 can be flexibly connected to any adjacent connection pad 1062 located on the flexible circuit board 106 along the axial direction of the catheter. Furthermore, signals with the same name can be merged and converged on the flexible circuit board 106.

[0045] Meanwhile, in this embodiment, since at least two adjacent IO pads 1042 are respectively bonded to connection pads 1062 of different functional layers, multiple rows of fan-out of multiple IO pads 1042 on the first surface of the control chip 104 are realized. Based on this, the pressure of the welding space of multiple connection pads 1062 on the flexible circuit board 106 can be effectively relieved by increasing the actual spacing between adjacent connection pads 1062 on the flexible circuit board 106, thereby improving the reliability of the wire bonding process and the manufacturing yield of 4D ultrasonic conduits. On the other hand, by directly using wire bonding, the various types of IO pads scattered in the wire bonding region 2 can be grouped into the corresponding functional layers as much as possible. This simplifies the classification and extraction of high-density interleaved signals and simultaneously fulfills the communication requirements of each type. Specifically, it preserves parallel transmission signal lines (such as digital signal lines and analog signal lines) or merges signal lines of the same type on the flexible circuit board (such as merging ground pads into the same ground signal line, and merging power pads of the same level into the same power signal line). This effectively ensures efficient and concise routing and also reduces the number of signal interfaces or centralized signal interfaces of the same type of signal lines when the flexible circuit board is directly or indirectly connected to an external host.

[0046] Optionally, such as Figure 1 As shown, the flexible circuit board 106 may also be provided with an adapter pad 1064 for connecting an external host. On the flexible circuit board 106, the adapter pad 1064 and the connecting pad 1062 are arranged opposite to each other (the two are respectively arranged on both sides of the axial direction of the flexible circuit board).

[0047] Signal lines refer to carriers used to connect pad 1062 to an external host, providing transmission paths for different types of signals in the 4D ultrasonic conduit. It is readily understood that, in the case where the flexible circuit board 106 also includes adapter pad 1064, signal lines are used to connect pad 1062 to adapter pad 1064.

[0048] For example, during the use of the 4D ultrasound catheter, the signal from the external host is transmitted sequentially to the control chip 104 via the adapter pad 1064, signal line, connection pad 1062, IO pad 1042, and central pad. The control chip 104 processes the signal from the external host and outputs a drive signal via the central pad to drive the transducer element 102 to emit ultrasonic signals. After the ultrasonic signal is reflected by human tissue, the transducer element 102 in operation receives an echo signal corresponding to the ultrasonic signal. The transducer element 102 generates an electrical signal based on the echo signal and outputs it to the central pad. The control chip 104 receives the echoed electrical signal via the central pad and generates image data based on the echoed electrical signal. Thus, the image data is transmitted sequentially to the external host via the IO pad 1042, connection pad 1062, signal line, and adapter pad 1064.

[0049] Currently, in 2D ultrasonic catheters, a thermoforming process is typically used to transmit signals to an external host. However, 2D ultrasonic catheters only require analog signal output, while 4D ultrasonic catheters, in addition to analog signals, also include single-ended digital signals, differential digital signals, power signals of different levels, and different ground signals requiring isolation. Furthermore, to ensure reliable power supply and communication between the control chip within the 4D ultrasonic catheter and the ultrasonic transducer array elements, multiple power, ground, and digital signals with the same name are often distributed across the control chip. This ensures that ultrasonic transducer array elements within a certain area can be easily and effectively connected to their respective I / O pads. In other words, almost no single type of signal—analog, power, ground, or digital—can be clustered within a single sub-area, making it difficult to centrally extract a single type of signal. Therefore, compared to conventional 2D ultrasonic catheters, 4D ultrasonic catheters have an additional requirement for merging, converging, and arranging these disparate signals, which is something that a thermoforming process cannot achieve. Therefore, for 4D ultrasonic catheters, the design needs to reserve space within a limited area to merge and converge the same-name signal IO pads scattered in different locations.

[0050] In one exemplary embodiment, such as Figure 1As shown, the axial spacing between the connection pads 1062 of different functional layers and the wire bonding region 2 is different, so that each connection pad 062 is exposed layer by layer. One implementation is as follows: the flexible circuit board 106 includes multiple functional layers, each functional layer is provided with several signal lines and multiple connection pads 1062; in the flexible circuit board 106, along a first direction parallel to the control chip 104 to multiple transducer array elements 102, each functional layer is stepped inward and exposed layer by layer on the side near the control chip 104, and the exposed part of each functional layer on the side near the control chip 104 is provided with multiple exposed connection pads 1062; the multiple functional layers include digital signal lines for transmitting transducer signals, analog signal lines, at least one ground signal line for transmitting ground signals, and at least one power signal line for transmitting power signals.

[0051] In this context, along a first direction parallel to the control chip 104 and extending to the multiple transducer elements 102 (i.e., the direction perpendicular to the axial direction of the conduit, also generally referred to as the radial direction), each functional layer near the control chip 104 is stepped inward and gradually exposed. This means that among the multiple functional layers included in the flexible circuit board 106, each functional layer extends axially and includes an end near the control chip 104 and an end away from the control chip 104. The flexible circuit board 106 forms multiple gradually recessed steps. Based on this, the connection pads 1062 of each functional layer can be fully exposed without being blocked by an adjacent functional layer in the first direction. Therefore, it is easy to understand that along the first direction from the control chip 104 to the multiple transducer elements 102, the distance between the side of each functional layer near the control chip 104 and the control chip 104 increases progressively.

[0052] As is easily understood, since each functional layer forms multiple progressively recessed steps along the first direction from the control chip 104 to the multiple transducer array elements 102, the connection pads 1062 located at the end of each functional layer closest to the control chip 104 will not only not be blocked by the adjacent functional layer in the first direction, but also will not be blocked by any functional layer in the first direction.

[0053] As is easily understood, since each functional layer in the flexible circuit board 106 is stepped inward and exposed layer by layer on the side closest to the control chip 104, in the wire bonding region 2 of the control chip 104, the multiple metal bonding leads 108 used to realize the bonding connection between multiple connection pads 1062 and multiple IO pads 1042 gradually shorten in the opposite direction of the first direction, and the multiple metal bonding leads 108 present a slightly curved shape. That is to say, the multiple metal bonding leads 108 in the wire bonding region 2 of the control chip 104 naturally present a radial shape.

[0054] Optionally, if the width of each functional layer in the flexible circuit board 106 is consistent, in order to make each functional layer recessed in a stepped manner on the side close to the control chip 104 and exposed layer by layer, it can also be understood that, along the first direction from the control chip 104 to the multiple transducer array elements 102, the length of each functional layer gradually decreases in the second direction from the flexible circuit board 106 to the control chip 104.

[0055] As can be seen, in this embodiment, since each functional layer in the flexible circuit board 106 is stepped inward and exposed layer by layer on the side closest to the control chip 104, the flexible circuit board 106 can achieve a specific connection method with the control chip 104. Therefore, the specific connection method in this embodiment is more in line with the requirements of high-density, high-performance electrical design, which helps to further improve the signal integrity and power integrity of the 4D ultrasound catheter.

[0056] In one exemplary embodiment, the axial spacing between the connection pads 1062 of different functional layers and the wire bonding region 2 is different. Another way to achieve the gradual exposure of each connection pad 1062 is as follows: the edges of each functional layer are flush, each functional layer has a cutout hole, and the size of the cutout hole on each functional layer is different. Along a first direction parallel to the control chip 104 to the multiple transducer array elements 102, each cutout hole increases in size sequentially. The connection pads 1062 of each functional layer are set near the cutout hole. Based on the gradual increase of the cutout hole, the connection pads 1062 near the cutout hole of the next functional layer fall within the projection range of the cutout hole of the previous functional layer. Similarly, the stacked functional layers expose the connection pads 1062 of each functional layer in the cutout hole area of ​​each functional layer layer through the cutout holes of each layer.

[0057] The flush edges of each functional layer mean that the sides of each functional layer facing the control chip 104 are of equal length, meaning that the flexible circuit board 106 does not form a stepped edge on the side facing the control chip 104. Similarly, this embodiment can also provide ample layout space for the connection pads 1062.

[0058] It is understood that the multi-layered functional layers mentioned in this application, stacked along a direction perpendicular to the catheter axis, do not impose any restrictions on the shape of each functional layer. For the stepped, gradually receding stack, all multi-layered functional layers are contained within the distal end of the catheter body. Specifically, these multiple functional layers can be considered as inner, middle, and outer functional layers. The outer functional layer is the one closest to the catheter body wall, the inner functional layer is the one furthest from the catheter body wall, and the middle functional layer is one or more functional layers between the outer and inner functional layers. Figure 3 In this implementation, the inner functional layer is the functional layer furthest from the catheter body wall and closest to the axis of the catheter body cavity. It should also be noted that, except for the portion of the flexible circuit board 106 connected to the control chip 104, the multi-layer functional layers and the control chip 104 are generally axially offset, which helps to reduce the overall radial dimension. The multiple connection pads 1062 of the multi-layer functional layers have axial spacing with the wire bonding region 2 of the control chip 104. It is not required that any one of the multi-layer functional layers be at the same height as the wire bonding region 2; that is, it is neither required nor restricted that the axial spacing between a certain IO pad in the wire bonding region 2 and the connection pad 1062 is equal to the distance between that IO pad and the connection pad 1062.

[0059] In one exemplary embodiment, such as Figure 1 As shown, any type of signal pad of multiple IO pads 1042 is dispersed in the wire bonding region 2; multiple functional layers are dedicated signal layers for transmitting one of digital signals, analog signals, power signals or ground signals, or at least some functional layers are mixed signal layers for transmitting at least two of digital signals, analog signals, power signals or ground signals.

[0060] A dedicated signal layer for transmitting a specific signal is called a functional layer for transmitting that signal. Specifically, a dedicated signal layer for transmitting digital signals refers to a functional layer whose internal signal lines are specifically designed for transmitting digital signals. Similarly, a dedicated signal layer for transmitting analog signals refers to a functional layer whose internal signal lines are specifically designed for transmitting analog signals; the same applies to dedicated signal layers for transmitting power or ground signals, so they will not be elaborated upon further here.

[0061] Optionally, in a dedicated signal layer for transmitting a certain type of signal, there may be multiple independent signal lines of the same type in a certain dedicated signal layer. For example, the number of signal lines used to transmit digital signals may be three, that is, the dedicated signal layer for transmitting digital signals may include a first digital signal line, a second digital signal line, and a third digital signal line, and the first digital signal line, the second digital signal line, and the third digital signal line may be used to transmit different digital signals respectively.

[0062] For example, different transducer signals can be transducer signals with different timings, that is, different transducer signals can be used to address different transducer array elements 102.

[0063] In an exemplary embodiment, at least one functional layer for transmitting power signals and / or ground signals is provided between functional layers for transmitting digital signals and / or analog signals.

[0064] For example, at least one functional layer for transmitting power signals and / or ground signals is provided between functional layers used for transmitting digital signals and / or analog signals. For example, there may be 6 functional layers, each of which is a dedicated signal layer for transmitting one of digital signals, analog signals, power signals, or ground signals. When the 6 functional layers include a first digital signal layer, a second digital signal layer, a third analog signal layer, a first ground layer, a second ground layer, and a power layer, the arrangement order of the 6 functional layers in the direction outward along the vertical axis may be: first digital signal layer, first ground layer, second digital signal layer, power layer, second ground layer, and third analog signal layer, or it may be: first digital signal layer, first ground layer, power layer, second digital signal layer, second ground layer, and third analog signal layer. Of course, the above are merely examples of feasible methods and are not exhaustive. It should be understood that the aforementioned first digital signal layer, second digital signal layer, third analog signal layer, and power layer do not mean that each layer has only one signal line. In fact, multiple signal lines that are insulated from each other can be set up for each function according to actual needs, so that the same type of high-density signals can be led out from the same layer. For example, by setting up power layer to lay out power signal lines that provide different levels, the different excitation requirements of control chip 104 can be met. This embodiment aims to use the power / ground layer as an isolation layer, which can significantly suppress crosstalk and noise coupling between digital signals and analog signals, while providing a good return path for high-speed signals, improving signal integrity and system stability.

[0065] Optionally, in the flexible circuit board 106, a plurality of connection pads 1062 provided at one end of a functional layer near the control chip 104 can be connected to a plurality of IO pads 1042 of the control chip 104 for transmitting the same type of signal, or can be connected to a plurality of IO pads 1042 of the control chip 104 for transmitting at least two different types of signals.

[0066] In some embodiments, multiple functional layers are dedicated signal layers for transmitting one of digital signals, analog signals, power signals, or ground signals, respectively. Alternatively, at least some functional layers are mixed signal layers for transmitting at least two of digital signals, analog signals, power signals, or ground signals. Thus, the same signal (or signal with the same name) is merged and converged in the same functional layer. Based on this, it helps to suppress signal crosstalk between different types of signals, further improving the transmission quality of high-frequency ultrasound signals. At the same time, it can also simplify the wiring of signal lines used to transmit different signals. Consequently, it can not only reduce the manufacturing difficulty of 4D ultrasound catheters, but also improve the stability of 4D ultrasound catheters during operation.

[0067] Optionally, the axial length of the functional layer containing the power signal line is not less than at least one other functional layer, thus providing a relatively long axial range for connecting capacitors and other devices. In the aforementioned embodiment where the functional layers extend in a stepped manner, the axial length of the functional layer containing the power signal line is not less than at least one other functional layer. That is, along the first direction, the axial length of the functional layer used to transmit the power signal is not less than at least one other functional layer. Preferably, the uppermost functional layer is not a power layer, thereby avoiding the phenomenon that the uppermost functional layer is too long due to directly placing capacitors or other devices on the power layer.

[0068] In some implementations, such as Figure 1 , Figure 3 , Figure 4 As shown, each functional layer also includes a transition pad 1064, which is connected to the connecting pad 1062 on both sides of the flexible circuit board 106 along the axial direction to transmit signals to the signal lines. Along the direction away from the duct axis, each functional layer recesses in a stepped manner on the side away from the control chip 104, gradually exposing the transition pads 1064 of each functional layer. The transition pads 1064 are used to connect to an external host via cables or a flexible transition board. This further improves the signal integrity and power integrity of the 4D ultrasonic duct.

[0069] The adapter pad 1064 refers to the interconnection interface located on the flexible circuit board 106 and directly connected to an external host. Since the adapter pad 1064 and the connecting pad 1062 are connected to opposite sides of the flexible circuit board 106 along its axial direction—that is, multiple connecting pads 1062 and multiple adapter pads 1064 are arranged back-to-back in the flexible circuit board 106—the multiple connecting pads 1062 are located on the side of the flexible circuit board 106 closer to the control chip 104, and the multiple adapter pads 1064 are located on the other side of the flexible circuit board 106 away from the control chip 104. Based on this, during the connection of the connecting pads 1062 to their corresponding adapter pads 1064 via signal lines, signal loss during the transmission of high-frequency ultrasonic signals can be avoided. Optionally, the adapter pad 1064 can be directly or by means of welding, hot pressing, etc., connected to the socket, connector or pad inside the 4D ultrasonic catheter operating handle, and then the 4D ultrasonic catheter operating handle is connected to the external host to realize the indirect connection between the adapter pad 1064 and the external host.

[0070] Optionally, the multiple transition pads 1064 located on each functional layer can also be exposed by opening windows on each functional layer. Based on this, since the multiple transition pads 1064 are located in the windowed areas of each functional layer, the extremely high difficulty and cost of making high-density microvias in the thin-layer area of ​​the flexible circuit board 106 can be completely avoided, which can significantly reduce the design and processing threshold of the flexible circuit board 106 itself.

[0071] In a further embodiment, in the flexible circuit board 106, each functional layer also includes a transition pad 1064. The transition pad 1064 and the connection pad 1062 are connected to both sides of the flexible circuit board 106 along the axial direction. The side of each functional layer closer to the control chip 104 is stepped inward and gradually exposes the connection pad 1062 of each functional layer. The side of each functional layer away from the control chip 104 is stepped inward and gradually exposes the transition pad 1064 of each functional layer. Therefore, the outer contours of the opposite sides of each functional layer of the flexible circuit board 106 (the transition side where the transition pad 1064 is located and the connection side where the connection pad 1062 is located) are symmetrically arranged.

[0072] In some exemplary embodiments, at least one of the connection pads of the functional layer can be connected to the signal line of another functional layer via vias, specifically including at least one of the following methods:

[0073] (1) The plurality of grounding pads are respectively connected to the grounding signal lines of different functional layers via leads, and at least two grounding signal lines in different functional layers are connected via vias, such as Figure 1 As shown, at least one grounding layer for transmitting ground signals includes a first grounding layer and a second grounding layer. At least one non-grounding layer is provided between the first grounding layer and the second grounding layer. The first grounding layer is provided with a first via pad, and the second grounding layer is provided with a second via pad. A via 1066 penetrating at least one non-grounding layer is provided between the first via pad and the second via pad. The first grounding layer is connected to the first via pad, and the second grounding layer is connected to the second via pad. The via 1066 is connected to the first via pad and the second via pad respectively, and is insulated from the non-grounding layer. The connection between the first grounding layer and the second grounding layer through the via 1066 is to reduce the potential difference between the different grounding layers, improve the overall shielding effectiveness, and reduce external electromagnetic interference and internal signal radiation.

[0074] The non-grounded layer located between the first ground layer and the second ground layer can be a signal layer or a power layer. Via 1066 refers to a conductive via used to achieve a connection between the first ground layer and the second ground layer.

[0075] Optionally, during the bonding connection between the connection pad 1062 and the IO pad 1042, the IO pad 1042 used for transmitting different signal types can be intentionally bonded to the corresponding connection pad 1062 of a certain functional layer to minimize the number of vias 1066 required for ground signal layer switching, and it may even be possible to eliminate the need for vias 1066 inside the flexible circuit board 106. Based on this, by avoiding the use of a large number of micro-vias 1066, and with the ample wiring resources of the connection area on the flexible circuit board 106 equipped with transition pads 1064, high-density, high-performance wiring can be achieved.

[0076] It should be noted that vias 1066 can only be set in different functional layers to achieve signal layer switching when multiple functional layers are multiple independent functional layers. That is to say, when multiple functional layers are an integral multi-layer structure formed by a single metal plate through a folding process, vias 1066 cannot be set.

[0077] It should be noted that, in the 4D ultrasonic conduit of this embodiment, multiple connection pads 1062 located at one end of each functional layer near the control chip 104 are exposed to the adjacent functional layer in the first direction. Based on this, in the presence of multiple functional layers, it is easy to understand that a large number of connection pads 1062 can be provided. Based on this, the wiring space between the control chip 104 and the flexible circuit board 106 is greatly increased. Therefore, the number of vias 1066 in the 4D ultrasonic conduit of this embodiment can be significantly reduced compared to conventional ultrasonic conduits.

[0078] (2) One of the digital signal pads, analog signal pads, and power pads is connected to a connection pad 1062 of a functional layer via a lead. The connection pad 1062 is connected to the signal line of another functional layer via a via. For example, assuming that a functional layer of the flexible circuit board 106 has 20 connection pads 1062 bonded to digital signal pads (corresponding to digital signal lines) and 5 connection pads bonded to power signal pads, this functional layer is a mixed signal layer. The 5 connection pads bonded to power signal pads can be connected to the power signal line of another functional layer via vias. In this way, when the number of connection pads 1062 (used to connect power signal lines) available for placement in another functional layer is limited, the 5 connection pads arranged in the mixed signal layer can be used. The 5 connection pads are connected to the functional layer where the placement of connection pads 1062 is limited via vias. This can alleviate the situation where the routing space for a certain type of signal line is relatively tight in actual implementation, and can also smoothly lay out all ground signal traces.

[0079] In some embodiments, by providing vias 1066 on different functional layers of the flexible circuit board 106, ground signals can be purposefully merged and converged through flexible connection methods when the wiring space in the area where the flexible circuit board 106 and the control chip 104 are bonded is limited. The signal lines used to transmit ground signals can be flexibly connected to an external host. Based on this, a mixed signal layer with more wiring space can help another mixed signal layer or dedicated signal layer with less wiring space to relieve wiring pressure through a mixed signal layer with more wiring space.

[0080] In some embodiments, such as Figure 1 As shown, a capacitor 1068 is provided in the flexible circuit board 106. Thus, through the power decoupling and energy storage functions of the capacitor 1068, the quality and stability of the power signal used to ensure the normal operation of the 4D ultrasound catheter can be guaranteed. Based on this, the high-frequency ultrasound signal can be ensured to have high transmission quality.

[0081] In one exemplary embodiment, such as Figure 1 , Figure 5 As shown, each functional layer is stacked in a direction perpendicular to the duct axis. The first surface of the functional layer furthest from the duct axis (i.e., the outer functional layer) is provided with a capacitor 1068, a third via pad, and a fourth via pad. The two ends of the capacitor 1068 are respectively connected to the third via pad and the fourth via pad. The third via pad is connected to the ground signal line of other functional layers through a via, and the fourth via pad is connected to the power signal line of other functional layers through a via.

[0082] The functional layer furthest from the conduit axis is insulated from both the third and fourth via pads. Capacitor 1068 serves as a power decoupling and energy storage unit, providing instantaneous high current and reducing power signal ripple. The distance between capacitor 1068 and the multiple connection pads 1062 of its corresponding functional layer is less than a second distance threshold. That is, capacitor 1068 is relatively close to the multiple connection pads 1062 of its corresponding functional layer.

[0083] In some embodiments, such as Figure 4As shown, multiple power pads are connected to the same power signal line via wire bonding, and multiple ground pads are connected to the same ground signal line via wire bonding. Specifically, the ratio of digital signal pads to digital signal lines is N:N; the ratio of analog signal pads to analog signal lines is M:M; the ratio of power pads to power signal lines is (W×P):P; and the ratio of ground pads to ground signal lines is (w×G):G.

[0084] The ratio of digital signal pads to digital signal lines is N:N, meaning the number of digital signal pads and digital signal lines is the same, and no signal merging or convergence occurs in the functional layer used for transmitting digital signals. Similarly, the ratio of analog signal pads to analog signal lines is M:M, indicating no signal merging or convergence occurs in the functional layer used for transmitting analog signals. While the signal output from digital and analog signal pads via leads does not reduce the number of signals by orders of magnitude, the wiring of flexible circuit boards, cables, adapter boards, and operating handle sockets is simplified by connecting similar signals to the same layer or multiple functional layers as much as possible. In other words, although the number of digital and analog signals remains unchanged on both the flexible circuit board and the control chip, the dispersion of similar signals on the flexible circuit board is far lower than that on the control chip.

[0085] Optionally, N, M, P, and G can each be an integer greater than or equal to 1. W and w are the convergence multiples of the power signal and ground pad after wire bonding, respectively. Both W and w are integers greater than or equal to 2, and W and w can be equal or unequal.

[0086] like Figure 4 The signal line 1070 shown can be any of the following: digital signal line, analog signal line, power signal line, or ground signal line. The ratio of the number of power pads to power signal lines is (W×P):P, and the ratio of the number of ground pads to ground signal lines is (w×G):G. That is to say, signal merging and convergence can occur in the functional layer used to transmit power signals or the functional layer used to transmit ground signals. In this embodiment, the merging of power signals of the same level can occur in the power layer (i.e., the functional layer used to transmit power signals), and the merging of ground signals can occur in the ground layer (i.e., the functional layer used to transmit ground signals). Based on this, by merging and converging signals of the same name, the wiring difficulty of 4D ultrasonic catheters can be significantly reduced by reducing the number of traces, thereby reducing the manufacturing cost of 4D ultrasonic catheters.

[0087] It is easy to understand that when at least one functional layer's connection pad 1062 can be connected to the signal line of another functional layer through a via 1066, and a capacitor 1068 is provided on the first surface of the functional layer furthest from the conduit axis, the via 1066 corresponding to the connection pad 1062 and the via 1066 connected to the capacitor 1068 are not the same via, but two different vias 1066.

[0088] In some embodiments, such as Figure 3 As shown, the 4D ultrasound catheter also includes an acoustically transparent section 202 for transmitting ultrasonic signals. The acoustically transparent section 202 is located at the distal end of the catheter body, and multiple transducer elements 102, a control chip 104, and a flexible circuit board 106 are all housed inside the catheter body. The acoustically transparent section 202 refers to the acoustically penetrating component on the 4D ultrasound catheter, or a local acoustically transparent area on the 4D ultrasound catheter. In essence, the acoustically transparent section 202 not only allows ultrasonic signals to be transmitted to human tissue but also allows the echo signal corresponding to the ultrasonic signal to be incident on the transducer elements 102. The acoustically transparent section 202 should have a low acoustic attenuation coefficient, high biocompatibility, and suitable acoustic impedance parameters. Based on these characteristics, the acoustically transparent section 202 can achieve efficient transmission of ultrasonic signals.

[0089] Optionally, the portion of the acoustic transmission section 202 corresponding to the plurality of transducer array elements 102 may have a flat surface. Based on this, by avoiding the variation of curvature in the portion of the acoustic transmission section 202 corresponding to the plurality of transducer array elements 102, parallel matching between the acoustic transmission section 202 and the plurality of transducer array elements 102 can be achieved, ensuring that the sound beam of the ultrasonic signal or echo signal will not be deflected, thereby improving the imaging quality of the 4D ultrasonic catheter.

[0090] In some embodiments, such as Figure 3As shown, the wire bonding region 2 of the control chip 104 includes a first bonding region region 2-1 and a second bonding region region 2-2 axially connected to both sides of the non-wire bonding region region 1; the flexible circuit board 106 includes a first flexible circuit board 106-1 and a second flexible circuit board 106-2, the first flexible circuit board 106-1 and the second flexible circuit board 106-2 each include multiple functional layers, and the multiple exposed connection pads 1062 in the first flexible circuit board 106-1 are used for connection with the substrate. Multiple I / O pads 1042 in the first bonding region 2-1 are wire-bonded together, and multiple exposed connection pads 1062 in the second flexible circuit board 106-2 are used for wire-bonding together with the multiple I / O pads 1042 in the second bonding region 2-2. The first flexible circuit board 106-1 is connected to the distal end of the control chip 104 and has a bending region 106-3. The first flexible circuit board 106-1 bends at the bending region 106-3, and the bending region 106-3 corresponds to the distal end of the conduit body. The bending region 106-3 corresponds to the end of the acoustically transparent portion 202. This allows for a more dispersed layout of the I / O pads on the control chip 104, effectively alleviating the problem of high I / O density caused by the traditional control chip 104 only having I / O leads on one side. Furthermore, this embodiment uses wire bonding to connect the I / O pads on both sides of the control chip 104 to the first flexible circuit board 106-1 and the second flexible circuit board 106-2, respectively. Because the metal bonding wires 108 have extremely fine diameters, there can be smaller spacing between the multiple I / O pads on the control chip 104, or between the multiple connection pads 1062 on the flexible circuit board 106. Consequently, the multiple metal bonding wires 108 occupy very little space inside the 4D ultrasonic catheter, which helps reduce the space occupied by the connection area between the control chip 104 and the flexible circuit board 106. Based on this, it can further contribute to the miniaturization of the 4D ultrasonic catheter in terms of size.

[0091] Optionally, the dimensions of the first flexible circuit board 106-1 and the second flexible circuit board 106-2 may be different. The functional layer stacking method of the first flexible circuit board 106-1 and the second flexible circuit board 106-2, the connection method of the first flexible circuit board 106-1 and the second flexible circuit board 106-2 to the control chip 104 respectively, or the connection method of the first flexible circuit board 106-1 and the second flexible circuit board 106-2 to the outside can all adopt the methods mentioned in any of the foregoing embodiments, and will not be repeated here.

[0092] In some embodiments, such as Figure 2As shown, the flexible circuit board 106 also includes a connecting portion 109, and the control chip 104 is disposed on the connecting portion 109. The functional layers of the first flexible circuit board 106-1 and the second flexible circuit board 106-2 are stacked in a direction perpendicular to the axial direction of the conduit. The connecting portion 109 is axially embedded between the inner functional layer of the first flexible circuit board 106-1 and the inner functional layer of the second flexible circuit board 106-2. Grounding signal lines are provided in the inner functional layers of the first flexible circuit board 106-1 and the second flexible circuit board 106-2. The connecting portion 109 connects the grounding signal lines of the two inner functional layers by providing a metal wire to form a continuous ground plane, thereby significantly improving the anti-interference capability of the control chip 104.

[0093] Optionally, the connecting portion 109 can be a flexible board area with metal wires. Since the first flexible circuit board 106-1 and the second flexible circuit board 106-2 are connected via the connecting portion 109, it can be understood that there is at least one functional layer connected between the first flexible circuit board 106-1 and the second flexible circuit board 106-2. This means that the first flexible circuit board 106-1 and the second flexible circuit board 106-2 are not completely independent; they have at least one interconnected or shared functional layer. Figure 4 or Figure 2 The functional layer (functional layer') in the middle.

[0094] For example, Figure 2 , Figure 3 and Figure 5 In the illustrated embodiment, the inner functional layers of the first flexible circuit board 106-1 and the second flexible circuit board 106-2 can serve as at least one functional layer connecting the first flexible circuit board 106-1 and the second flexible circuit board 106-2. Specifically, when the first flexible circuit board 106-1 and the second flexible circuit board 106-2 each include six functional layers, combined with... Figure 4 and Figure 2As can be seen, the first flexible circuit board 106-1 includes functional layers layer1, layer2, layer3, layer4, layer5, and layer6, and the second flexible circuit board 106-2 includes functional layers layer1', layer2', layer3', layer4', layer5', and layer6'. Furthermore, functional layers layer1 of the first flexible circuit board 106-1 and layer1' of the second flexible circuit board 106-2 are connected. That is, functional layer layer1 is the inner functional layer of the first flexible circuit board 106-1 mentioned above, and functional layer layer1' is the inner functional layer of the second flexible circuit board 106-2 mentioned above. Furthermore, grounding signal lines are provided in the inner functional layers of the first flexible circuit board 106-1 and the second flexible circuit board 106-2. The connecting part 109 connects the grounding signal lines of the two inner functional layers through the functional layer to form a continuous ground plane. Thus, on the one hand, it can provide mechanical support for the control chip 104, and on the other hand, it can significantly improve the anti-interference capability of the control chip 104, so as to further improve the transmission quality of different signals in the 4D ultrasonic catheter.

[0095] It is understood that, in actual implementation, the aforementioned combined structure can be obtained by stacking a first flexible circuit board 106-1 (excluding its inner functional layer) into a pre-stacked layer one, and stacking a second flexible circuit board 106-2 (excluding its inner functional layer) into a pre-stacked layer two. The pre-stacked layer one and the pre-stacked layer two are then stacked together on a bottom functional layer. Signal lines are provided inside this bottom functional layer, and different areas of this bottom functional layer serve as the inner functional layer of the first flexible circuit board 106-1, the inner functional layer of the second flexible circuit board 106-2, and the aforementioned connecting portion 109, respectively.

[0096] Optionally, based on the connection portion 109, the first surface of the control chip 104 includes a non-wire bonding region region 1 and a wire bonding region region 2. The wire bonding region region 2 is provided with a grounding pad that is wire bonded to the metal wire of the connection portion 109. Alternatively, the second surface of the control chip 104, which is opposite to the first surface (the side of the control chip 104 facing the ultrasonic transducer array 102), has a grounding pad that is connected to the metal wire of the connection portion 109 by solder or by direct bonding. Both of the aforementioned optional implementation methods, under the premise of setting the connecting part 109, aim to reduce the complexity of leading out part of the ground signal of the control chip 104 to the first flexible circuit board 106-1 and the second flexible circuit board 106-2 respectively. At the same time, by directly connecting part of the ground signal of the control chip 104 to the connecting part 109, it is beneficial to directly lead out the ground signal of the control chip 104 to a common ground plane, so as to avoid the ground potential of the two flexible boards being different, and to ensure signal integrity and data transmission correctness.

[0097] In some embodiments, when at least one functional layer of the first flexible circuit board 106-1 and the second flexible circuit board 106-2 is connected, a connecting portion 109 is provided on the first surface of the mechanical reinforcement structure 204 along the first direction. The control chip 104 is disposed on the connecting portion 109. Therefore, it can be understood that the inner functional layers of the first flexible circuit board 106-1 and the second flexible circuit board 106-2, as well as the control chip 104, are all disposed on the same side of the mechanical reinforcement structure 204 and are physically supported by it. The surface of the mechanical reinforcement structure 204 is flat, which can prevent local deformation of the portion of the flexible circuit board 106 disposed on its first surface. Based on this, the difficulty of implementing the wire bonding process between the bonding pad 1062 and the IO bonding pad 1042 can be reduced, and the mechanical reinforcement structure 204 can further optimize the yield rate of the wire bonding process used in this embodiment.

[0098] In some embodiments, such as Figure 3 or Figure 5 As shown, one end of the mechanical reinforcement structure 204 corresponds to the bending area 106-3 of the first flexible circuit board 106-1. Based on this, after the first flexible circuit board 106-1 bends in the bending area 106-3, the bent first flexible circuit board 106-1 can coil around the second surface of the mechanical reinforcement structure 204, so that the bending area 106-3 of the first flexible circuit board 106-1 can be shaped, thereby reducing stress damage to the signal line 1070 in the bending area 106-3 caused by bending. For example, as... Figure 5 As shown, Figure 5An enlarged schematic diagram of part A can be seen as follows Figure 2 The image shown is a schematic diagram of the structure of the first flexible circuit board 106-1 of the 4D ultrasound catheter from the main view before bending occurs.

[0099] The bending area 106-3 refers to the area pre-set on the first flexible circuit board 106-1 for bending deformation. The bending area 106-3 is a curved section formed on the first flexible circuit board 106-1 for the spatial layout inside the 4D ultrasound catheter. Bending the first flexible circuit board 106-1 based on the bending area 106-3 can achieve the reversible arrangement of the first flexible circuit board 106-1 inside the 4D ultrasound catheter without damaging the signal lines 1070 inside the first flexible circuit board 106-1.

[0100] The multiple functional layers of the first flexible circuit board 106-1 are at least partially layered in the bending region 106-3. This means that the multiple functional layers of the first flexible circuit board 106-1 are not tightly bonded together in the bending region 106-3, but at least partially not bonded together. That is, at least some functional layers are separated and loosened from each other in the bending region. It is easy to understand that this arrangement facilitates smoother bending of the first flexible circuit board 106-1 in the bending region 106-3.

[0101] Optionally, when the multiple functional layers are multiple independent functional layers, the first flexible circuit board 106-1 may not have an insulating adhesive layer between adjacent functional layers in at least two of the functional layers in the bending region 106-3. That is, the at least two functional layers in the bending region 106-3 are not bonded together but remain in a loose state that can be bent independently. Based on this, the flexibility and bendability of the first flexible circuit board 106-1 in the bending region 106-3 can be enhanced, the stress damage suffered by the first flexible circuit board 106-1 after bending in the bending region 106-3 can be reduced, and the bending of the first flexible circuit board 106-1 can be made smoother.

[0102] Optionally, when multiple functional layers are integral multilayer structures formed by folding single metal plates, the first flexible circuit board 106-1 may have a slit in at least the uppermost part of the functional layer closest to human tissue in the bending area 106-3. Based on this, the slit can avoid stress accumulation during bending, enhance the flexibility and bendability of the first flexible circuit board 106-1 in the bending area 106-3, reduce stress damage to the first flexible circuit board 106-1 after bending in the bending area 106-3, and make the bending of the first flexible circuit board 106-1 smoother.

[0103] After the first flexible circuit board 106-1 is bent in the bending region 106-3, multiple transducer array elements 102, control chip 104, the bent first flexible circuit board 106-1, and the second flexible circuit board 106-2 are placed inside the sound-permeable portion 202. For example, epoxy adhesive (not shown) can be used to encapsulate and protect the interior of the sound-permeable portion 202 to achieve both fixation and protection, resulting in... Figure 3 The assembly structure of the distal end of the catheter is shown.

[0104] In one exemplary embodiment, an imaging device is also provided, including a 4D ultrasound catheter as described in any of the 4D ultrasound catheter embodiments above.

[0105] In the description of this specification, the references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiment or example. The technical features of the embodiments described above can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; however, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0106] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A 4D ultrasonic catheter, characterized in that, It includes the catheter body and multiple transducer array elements, control chip and flexible circuit board disposed inside the distal end of the catheter body; The multiple transducer array elements are arranged in a matrix; The control chip includes a non-wire bonding region and a wire bonding region. The non-wire bonding region is provided with multiple central pads, and the multiple central pads are connected to the multiple transducer array elements one by one through solder or direct bonding. The wire bonding region is provided with multiple I / O pads, and the signal pad types of the multiple I / O pads are divided into digital signal pads, analog signal pads, power pads and ground pads. The flexible circuit board includes multiple functional layers. Each functional layer is provided with several signal lines and multiple connection pads. The connection pads are connected to the I / O pads by wire bonding. The signal types of the signal lines are divided into digital signal lines, analog signal lines, power signal lines, or ground signal lines. The flexible circuit board, control chip, and multiple transducer array elements are connected in sequence to excite the transducer array elements to emit ultrasonic signals and feed back processed echo electrical signals.

2. The 4D ultrasonic catheter according to claim 1, characterized in that, The functional layers are stacked in a direction perpendicular to the axial direction of the conduit, and the axial spacing between the connection pads of different functional layers and the wire bonding area is different, so that the connection pads are exposed layer by layer. At least two adjacent IO pads are respectively connected to connection pads of different functional layers via wire bonding.

3. The 4D ultrasonic catheter according to claim 2, characterized in that, Each of the functional layers further includes a transition pad, which is connected to the connection pad on both sides of the flexible circuit board along the axial direction to transmit signals to the signal line; along the direction away from the axial direction of the conduit, the side of each functional layer away from the control chip is stepped back and the transition pad of each functional layer is exposed layer by layer. The adapter pad is used to connect to an external host via a cable or a flexible adapter board.

4. The 4D ultrasonic catheter according to claim 1, characterized in that, Multiple power pads are connected to the same power signal line via wire bonding, and multiple ground pads are connected to the same ground signal line via wire bonding, specifically including: The ratio of the number of digital signal pads to the number of digital signal lines is N:N; The ratio of the number of analog signal pads to the number of analog signal lines is M:M; The ratio of the number of power pads to the number of power signal lines is (W×P):P; The ratio of the number of grounding pads to grounding signal lines is (w×G):G.

5. The 4D ultrasonic catheter according to claim 1, characterized in that, Any type of signal pad among the multiple IO pads is dispersed in the wire bonding area; The plurality of said functional layers are dedicated signal layers for transmitting one of digital signals, analog signals, power signals or ground signals, or at least some of said functional layers are mixed signal layers for transmitting at least two of digital signals, analog signals, power signals or ground signals.

6. The 4D ultrasonic catheter according to claim 1, characterized in that, At least one of the connection pads of the functional layer can be connected to the signal line of another functional layer via a via, specifically including at least one of the following methods: The plurality of grounding pads are respectively connected to grounding signal lines of different functional layers by leads, and at least two grounding signal lines disposed in different functional layers are connected by vias; One of the digital signal pads, analog signal pads, power pads, and ground pads is connected to a connection pad of a functional layer via a lead, and the connection pad is connected to a signal line of another functional layer via a via.

7. The 4D ultrasonic catheter according to claim 1, characterized in that, At least one functional layer for transmitting power signals and / or ground signals is provided between the functional layers used for transmitting digital signals and / or analog signals; and / or, The axial length of the functional layer containing the power signal line is not less than that of at least one other functional layer.

8. The 4D ultrasonic catheter according to claim 1, characterized in that, The functional layers are stacked in a direction perpendicular to the axial direction of the conduit. The first surface of the functional layer furthest from the conduit axis is provided with a capacitor, a third via pad, and a fourth via pad. The two ends of the capacitor are respectively connected to the third via pad and the fourth via pad. The third via pad is connected to the ground signal line of other functional layers through a via, and the fourth via pad is connected to the power signal line of other functional layers through a via.

9. The 4D ultrasonic catheter according to claim 1, characterized in that, The wire bonding region of the control chip includes a first bonding region and a second bonding region axially connected to both sides of the non-wire bonding region. The flexible circuit board includes a first flexible circuit board and a second flexible circuit board. The first flexible circuit board and the second flexible circuit board each include a plurality of functional layers. The plurality of exposed connection pads in the first flexible circuit board are used for wire bonding to a plurality of I / O pads located in the first bonding area, and the plurality of exposed connection pads in the second flexible circuit board are used for wire bonding to a plurality of I / O pads located in the second bonding area. The first flexible circuit board is connected to the distal end of the control chip and has a bending area. The first flexible circuit board bends in the bending area, and the bending area corresponds to the distal end of the catheter body.

10. The 4D ultrasonic catheter according to claim 9, characterized in that, The 4D ultrasound catheter also includes a mechanical reinforcement structure; The first flexible circuit board bends around the mechanical reinforcement structure, and multiple functional layers of the first flexible circuit board are at least partially layered in the bending region so that the bending region bends around the distal end of the mechanical reinforcement structure. The connection pads of the first flexible circuit board and the second flexible circuit board, as well as the control chip, are all disposed on the same side surface of the mechanical reinforcement structure.

11. The 4D ultrasonic catheter according to claim 9, characterized in that, The flexible circuit board further includes a connecting portion, and the control chip is disposed on the connecting portion. Each functional layer of the first flexible circuit board and the second flexible circuit board is stacked in a direction perpendicular to the axial direction of the conduit. The connecting portion is axially embedded between the inner functional layer of the first flexible circuit board and the inner functional layer of the second flexible circuit board. Both the inner functional layer of the first flexible circuit board and the inner functional layer of the second flexible circuit board are provided with grounding signal lines. The connecting part connects the grounding signal lines of the two inner functional layers through a metal wire to form a continuous ground plane. The first surface of the control chip includes the non-wire bonding region and the wire bonding region, the wire bonding region being provided with a ground pad connected to the metal wire via wire bonding; or, the second surface of the control chip is disposed opposite to the first surface, the second surface having a ground pad connected to the metal wire via solder or direct bonding.

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