Ultrasonic imaging catheter and method for cutting piezoelectric material

Abstract

The invention discloses an ultrasonic imaging catheter and a method for cutting a piezoelectric material in the technical field of medical ultrasonic imaging. The ultrasonic imaging catheter comprises a sheathing canal and a miniature phased array, and a flexible circuit electrically connected with the miniature phased array is arranged in the sheathing canal. And a handle for driving the sheath tube to radially deflect and / or axially move is arranged at one end of the sheath tube. The miniature phased array is arranged at the end, away from the handle, of the sheathing canal. The cutting gap of the piezoelectric material is reduced to the maximum extent through multiple times of laser cutting, so that the array element specifications are consistent, and the array element width loss is reduced; and through the curing effect of the structural adhesive, stable intervals are kept between the array elements. Therefore, the sound energy loss of the micro phased array caused by the dimension on the elevation angle of the array element is made up and reduced by increasing the width of the array element, so that the imaging quality is ensured. Therefore, the size of the cross section of the intracardiac ultrasonic imaging catheter is reduced, and damage to blood vessels is reduced.

Description

Technical Field

[0001] This invention relates to the field of medical ultrasound imaging technology, specifically to an ultrasound imaging catheter and a method for cutting piezoelectric materials. Background Technology

[0002] Intracardiac echocardiography (ICE) is an interventional ultrasound technique that uses a catheter inserted into the heart chambers via a peripheral blood vessel to effectively image and detect the various chambers, valves, and myocardium of the heart, and to observe whether the heart's pumping function is abnormal.

[0003] Ultrasound imaging catheters consist of a miniature phased array and a sheath. The miniature phased array is the core component of the catheter and is typically located at the end of the sheath. A larger elevation angle of the miniature phased array improves the imaging quality of the ultrasound imaging catheter, but this also limits the diameter of the sheath, resulting in a cross-sectional size that generally exceeds 9Fr (approximately 3mm). This standard size of ultrasound imaging can easily cause mechanical damage to delicate blood vessels. To reduce this damage, the elevation angle of the miniature phased array needs to be reduced, resulting in a smaller catheter diameter and thus less adverse effects on the blood vessels. However, this leads to a decrease in the imaging quality of the ultrasound imaging catheter. Summary of the Invention

[0004] The purpose of this invention is to disclose an ultrasound imaging catheter that reduces the gap between array elements to 20μm-25μm, thereby increasing the width of the array elements and improving the imaging quality of the ultrasound imaging catheter. This allows for a reduction in the size of the micro phased array in the elevation direction, which in turn allows for a smaller diameter of the ultrasound imaging catheter, thus reducing damage to blood vessels.

[0005] To achieve the above objectives, the present invention discloses an ultrasound imaging catheter, comprising: A sheath, the interior of which is provided with a flexible circuit; A miniature phased array is disposed at one end of the sheath and electrically connected to one end of the flexible circuit; the miniature phased array includes a piezoelectric material layer, the piezoelectric material layer includes multiple array elements distributed in an array, each array element is electrically connected to the flexible circuit, and the gap size S between adjacent array elements is 20μm-25μm.

[0006] As an optional implementation, the outer diameter D1 of the sheath is 2.23mm-2.43mm, and / or the inner diameter D2 is 1.9mm-2.1mm.

[0007] As an optional implementation, the width L1 of the cross-section of the flexible circuit is 1.4mm-1.6mm and the height h is 0.1mm-0.3mm, and / or the width L2 of the cross-section of the micro phased array is 1.4mm-1.6mm and the height H is 1.6mm-1.8mm.

[0008] As an optional implementation, the sheath further includes a stacked inner tube and a braided filament layer, the braided filament layer surrounding the outer periphery of the inner tube, the inner tube having a conduit space, and the flexible circuit disposed within the conduit space of the inner tube.

[0009] As an alternative implementation, the sheath further includes a protective layer material surrounding the side of the braided filament layer opposite to the inner tube.

[0010] As an optional implementation, the sheath further includes multiple traction ropes, which are embedded in the inner tube and spaced apart circumferentially along the inner tube; the traction ropes extend along the length of the sheath; the ultrasound imaging catheter also includes a handle, one end of the sheath is used to connect to the handle; one end of the traction rope passes through the sheath and is connected to the handle, and the other end is connected to the end of the sheath away from the handle.

[0011] As an optional implementation, the micro phased array further includes a matching layer and a backing layer; the electrode layer includes a ground electrode and a positive electrode, and the piezoelectric material layer is disposed between the ground electrode and the positive electrode; the matching layer is disposed on the side of the ground electrode away from the piezoelectric material; and the backing layer is disposed on the side of the positive electrode away from the piezoelectric material.

[0012] As an optional implementation, the matching layer includes a first matching layer and a second matching layer that are bonded to each other, with the second matching layer bonded to the grounding electrode.

[0013] On the other hand, the present invention discloses a method for cutting piezoelectric materials for the aforementioned micro phased array, the method being as follows: S1. Laser cutting: Using a laser to cut the piezoelectric material into multiple array elements of equal width and thickness; S2. Grouting: Injecting structural adhesive to encapsulate the array elements within the structural adhesive; S3. Curing: Allow to stand until the structural adhesive solidifies, and the gaps between the different array elements remain stable.

[0014] As an optional implementation, a laser is used to cut the piezoelectric material into multiple array elements of equal thickness and width, including: S11: A high-power picosecond laser is used to cut the piezoelectric material into array elements of equal width and thickness, and grooves are formed between different array elements; S12: Use a low-power picosecond laser to continue cutting the groove, and trim the edges of the groove to make the edges of the groove array elements smoother.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The gap size S between array elements is reduced to 20μm-25μm, which increases the width of the array elements; more acoustic energy can be generated while maintaining the same excitation intensity, so as to ensure imaging quality.

[0016] (2) Reducing the size of the micro phased array in the elevation direction also reduces the cross-sectional size of the sheath; the refined ultrasound imaging catheter causes less damage to blood vessels. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a longitudinal cross-sectional view of the assembled sheath and micro phased array disclosed in an embodiment of the present invention; Figure 2 yes Figure 1 Enlarged view of point A in the middle; Figure 3 This is a cross-sectional view of the sheath disclosed in an embodiment of the present invention; Figure 4 This is a schematic diagram of the assembly structure of a micro phased array and flexible circuit disclosed in an embodiment of the present invention; Figure 5 yes Figure 4 Projection view in the direction of arrow B; Figure 6 This is a schematic diagram of the array element cutting disclosed in an embodiment of the present invention; Explanation of key figure labels: 1. Sheath; 11. Inner tube; 111. Traction rope; 12. Braided filament layer; 121. Protective material layer; 13. Flexible circuit; 2. Miniature phased array; 21. Backing layer; 22. Piezoelectric material layer; 221. Array element; 222. Groove; 23. Electrode layer; 231. Ground electrode; 232. Positive electrode; 24. Matching layer; 241. Second matching layer; 242. First matching layer. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0021] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0022] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0023] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0024] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0025] Please see Figures 1 to 4This application provides an ultrasound imaging catheter, including a sheath 1, a miniature phased array 2, a handle, and a connector. The sheath 1 has a flexible circuit 13 inside, and one end of the sheath 1 is connected to a handle that drives the radial deflection and axial movement of the sheath 1. Mechanical force is applied to the sheath 1 by operating a knob on the handle to drive the tip of the sheath 1 away from the handle towards the target direction, flexibly adjusting the probe position. By pushing or retracting the handle, the overall depth of the sheath 1 within the blood vessel or heart chamber is controlled, and its deflection function enables three-dimensional spatial positioning of the sheath 1. A self-locking key is provided on the handle, which locks the sheath 1 at a selected depth or angle.

[0026] The miniature phased array 2 is located at the tip of the sheath 1 furthest from the handle and is electrically connected to one end of the flexible circuit 13. The other end of the flexible circuit 13 is electrically connected to a connector, which transmits the signals received by the miniature phased array 2 through the flexible circuit 13 to an external imaging system. The user observes the ultrasound images generated in real time by the miniature phased array 2 through the imaging system and dynamically adjusts the handle operation in real time to precisely point the miniature phased array 2 at the tip of the sheath 1 towards the target area, achieving "hand-eye coordination" interventional operation.

[0027] The miniature phased array 2 includes a piezoelectric material layer 22 and an electrode layer 23. The piezoelectric material layer 22, typically made of PZT ceramic or PVDF polymer, is the core of the miniature phased array 2. It utilizes its inverse piezoelectric effect (electrical signal → mechanical vibration) to convert high-frequency electrical signals into ultrasonic waves, and simultaneously converts received echo signals into electrical signals through the direct piezoelectric effect (mechanical vibration → electrical signal). The piezoelectric material layer 22 includes multiple array elements 221 distributed in an array, with uniform spacing and independent operation. The array elements 221 are generally formed by cutting piezoelectric material. Multiple different array elements 221 receive or release electrical signals through the electrode layer 23. All different array elements 221 are electrically connected to a flexible circuit 13, which is an integrated circuit board where electronic components are soldered onto a flexible substrate, possessing characteristics of simplified circuitry and good deformation capability. In conventional micro phased arrays, to ensure that adjacent array elements 221 do not interfere with each other during operation, the gap size S between array elements 221 is 40μm-50μm. However, in this embodiment, the gap size S between adjacent array elements 221 is reduced to a range of 20μm-25μm, specifically 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, etc. In this embodiment, the gap size S between adjacent array elements 221 can be processed to 20μm, thereby increasing the width of the array elements 221 and improving the imaging quality of the ultrasound imaging catheter.

[0028] In some embodiments, the outer diameter D1 of the sheath 1 is a value in the range of 2.23mm-2.43mm, specifically 2.23mm, 2.25mm, 2.33mm, 2.35mm, 2.43mm, etc., and / or the inner diameter D2 is a value in the range of 1.9mm-2.1mm, specifically 1.9mm, 1.92mm, 1.95mm, 2.0mm, 2.1mm, etc. In this embodiment, the outer diameter D1 of the sheath 1 is 2.33mm, and the inner diameter is 2.0mm.

[0029] In some embodiments, the width L1 of the cross-section of the flexible circuit 13 is a value in the range of 1.4mm-1.6mm, specifically 1.43mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, etc.; the height h is a value in the range of 0.1mm-0.3mm, specifically 0.13mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, etc. and / or the width L2 of the cross-section of the micro phased array 2 is a value in the range of 1.4mm-1.6mm, specifically 1.43mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, etc.; the height H is a value in the range of 1.6mm-1.8mm, specifically 1.63mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, etc. In this embodiment, the width L1 of the cross-section of the flexible circuit 13 is 1.5 mm and the height h is 0.2 mm; the width L2 of the cross-section of the micro phased array 2 is 1.5 mm and the height H is 1.7 mm.

[0030] The cross-sectional dimensions of conventional ultrasound imaging catheters typically exceed 9Fr (approximately 3mm), which is much larger than the 2.33mm outer diameter of the sheath 1 in this embodiment. By reducing the size of the micro-phased array 2 in the elevation direction while maintaining imaging quality, the diameter of the sheath 1 can be made smaller, thereby reducing the size of the ultrasound imaging catheter and minimizing damage to blood vessels from the refined catheter.

[0031] See Figures 4 to 5 In this embodiment, the elevation angle dimension of the micro phased array 2 refers to... Figure 4 The dimension L1 of the shape of the micro phased array 2 projected onto the plane along the direction of arrow B is given. Since the micro phased array 2 is a cuboid, the dimension of the micro phased array 2 in the elevation direction is also the width dimension of the cross-section of the micro phased array 2. Figure 5 L2 in the figure refers to the dimension of the flexible circuit 13.

[0032] See Figures 2 to 3In this embodiment, the sheath 1 further includes a stacked inner tube 11 and a braided filament layer 12. The braided filament layer 12 surrounds the outer periphery of the inner tube 11. The inner tube 11 has a conduit space, within which the flexible circuit 13 is disposed. The inner tube 11 provides protection for the flexible circuit 13. The inner tube 11 is typically made of a highly elastic polymer material such as polyurethane or polyimide, combining flexibility and durability to ensure signal transmission stability. The braided filament layer 12 wraps around the outer wall of the inner tube 11 and is generally a mesh structure woven from high-strength metal wires such as nickel-titanium alloy or stainless steel. The braided filament layer 12 provides the sheath 1 with overall tensile strength and anti-kinking ability, preventing the ultrasound imaging catheter from deforming or collapsing at vascular bends, while also giving the sheath 1 a certain degree of flexibility, allowing it to adapt to the complex anatomical structure of the heart chamber or blood vessels.

[0033] In some embodiments, the sheath 1 further includes a protective material layer 121, which surrounds the side of the braided filament layer 12 opposite to the inner tube 11. The protective material layer 121 can be made of materials such as polyurethane, polytetrafluoroethylene (PTFE), or coated polymers. Covering the braided filament layer 12, the protective material layer 121 isolates the braided filament layer 12 from direct contact with the external environment, reducing friction-induced wire breakage, burrs, or wear, and preventing structural failure of the ultrasound imaging catheter (such as localized strength reduction or fragment detachment) caused by damage to the braided filament layer 12. The braided filament layer 12 is subjected to repeated tensile-compressive stress during the deflection of the ultrasound imaging catheter, which may lead to wire fatigue with prolonged use. The flexible material of the protective material layer 121 disperses stress concentration, delays the propagation of fatigue cracks in the braided filaments, and extends the catheter's service life. If the metal braided filament layer 12 directly contacts the inner wall of the blood vessel, its rigid edges or burrs may scratch the vessel wall, causing inflammatory reactions, thrombosis, or vasospasm. The protective material layer 121 is typically made of highly elastic, low-friction, biocompatible materials such as polyurethane or PTFE. Its smooth and soft surface significantly reduces frictional resistance between the catheter and the vessel wall, minimizing mechanical damage to vascular endothelial cells and lowering the risk of postoperative complications. Metal braided wires easily adsorb proteins or platelets from the blood, potentially inducing thrombosis. The protective material layer 121 can be further modified using surface modification techniques to inhibit platelet aggregation and improve the catheter's blood compatibility, making it particularly suitable for prolonged procedures. The protective material layer 121 is generally chemically resistant, and its smooth surface does not easily retain blood or tissue debris, facilitating pre- and post-operative cleaning and disinfection, meeting stringent medical sterilization requirements.

[0034] In some embodiments, the sheath 1 further includes multiple traction cords 111, which are embedded in the inner tube 11 and spaced circumferentially along the inner tube 11, extending along the length of the sheath 1. The ultrasound imaging catheter also includes a handle, with one end of the sheath 1 connected to the handle. One end of the traction cord 111 passes through the sheath 1 and is connected to the handle, while the other end is connected to the end of the sheath 1 furthest from the handle. The traction cord 111 is typically made of high-strength, low-elongation metal wire or synthetic fiber, such as nickel-titanium alloy wire or Kevlar fiber, to ensure the accuracy and stability of tension transmission. When the doctor operates the knob on the handle, the knob applies tension to a specific traction rope 111 through the internal mechanical structure of the handle, while the other traction ropes 111 remain slack. Since the traction ropes 111 are evenly distributed, the tension only acts on a local area of ​​the tip of the micro phased array 2 installed in the sheath 1 (e.g., unidirectional tension causes the tip to bend to one side), while the braided filament layer 12 provides a reverse support force to prevent the overall deformation of the sheath 1, thereby achieving controllable radial deflection (e.g., bending to the left / right or up / down). By switching the tension of the handle on different traction ropes 111 (e.g., alternately tightening adjacent traction ropes 111), the micro phased array 2 can be combined to rotate at multiple angles as the sheath 1 deflects, thus flexibly adjusting the position and orientation of the micro phased array 2.

[0035] See Figure 4 In some embodiments, the micro phased array 2 further includes a matching layer 24 and a backing layer 21. The electrode layer 23 includes a ground electrode 231 and a positive electrode 232, and a piezoelectric material layer 22 is disposed between the ground electrode 231 and the positive electrode 232. The matching layer 24 is disposed on the side of the ground electrode 231 away from the piezoelectric material 22, and the backing layer 21 is disposed on the side of the positive electrode 232 away from the piezoelectric material layer 22.

[0036] Grounding electrode 231 and positive electrode 232 are used to apply an electric field to drive the mechanical vibration of the piezoelectric material. Electrode layer 23 is typically made of a highly conductive metal (such as gold, silver, or platinum) to ensure efficient transmission of electrical signals. Matching layer 24 can reduce acoustic impedance mismatch and improve ultrasonic wave transmission efficiency. Backing layer 21 is made of a material with high acoustic impedance and high attenuation coefficient (such as tungsten powder-doped epoxy resin or heavy metal composite material). Its functions include absorbing back-propagating sound waves, converting the energy of back-propagating sound waves into heat energy through the viscous loss and scattering effect of the material, reducing noise interference, and controlling the focusing of the sound beam. The acoustic properties of backing layer 21, such as density and elastic modulus, can affect the vibration mode of the piezoelectric material, assisting in achieving dynamic focusing of the sound beam. Flexible circuit 13 is responsible for transmitting high-frequency electrical signals from the external host to electrode layer 23 and transmitting the echo signals received by piezoelectric material layer 22 back to the processing system.

[0037] In some embodiments, the matching layer 24 includes a first matching layer 242 and a second matching layer 241 that are bonded to each other, with the second matching layer 241 bonded to the ground electrode 231. The acoustic impedance of the matching layer 24 is between that of piezoelectric materials and human tissue. The gradient acoustic impedance design of the multi-layer matching layer 24 can significantly reduce sound wave reflection and improve the transmission efficiency of ultrasound.

[0038] See Figure 4 A method for cutting piezoelectric materials, used in the aforementioned micro phased array 2, is as follows: S1. Laser cutting: Using a laser to cut piezoelectric materials into multiple array elements 221 of equal width and thickness; S2. Grouting: Inject structural adhesive to encapsulate the array element 221 within the structural adhesive. S3. Curing: Allow to stand until the structural adhesive solidifies, and the gaps between different array elements 221 remain stable.

[0039] Before laser cutting, the piezoelectric material needs to undergo some pretreatment. First, the surface of the piezoelectric material is cleaned by plasma cleaning or ultrasonic cleaning to remove impurities such as oil and oxides, avoiding carbonization or heat-affected zones during laser processing. Second, a light-absorbing coating, such as a thin layer of carbon black or a special laser absorber, is applied to the material surface to enhance laser energy absorption efficiency and reduce reflection loss, thus ensuring the uniformity of cutting in all areas of the piezoelectric material.

[0040] Array element 221 is rectangular. Consider the sound pressure at a point on the far-field axis as follows:

[0041] Where r is the distance from the spatial point to the sound source, A1 is the area of ​​the rectangular array element 221, and P0 is the initial sound pressure. From the above formula, it can be seen that the ultrasonic sound field energy is proportional to the area of ​​the array element 221. Therefore, if the length of the micro-phased array 2 in the elevation direction is reduced (…), the energy will increase. Figure 5 The size L1 in the image will reduce the sound field intensity. The reduction in the size of the micro phased array 2 in the elevation direction, that is, the reduction in the size of the array element 221 in the elevation direction, will lead to the loss of acoustic energy of the micro phased array 2, which will impair the imaging quality of the ultrasound imaging catheter.

[0042] In this embodiment, the piezoelectric material is cut into multiple independent array elements 221 of equal width and thickness using laser cutting, ensuring the uniformity of the array element 221 dimensions. This high-precision non-contact cutting method minimizes the cutting gap of the piezoelectric material, effectively increasing the width of the array element 221 for the same area of ​​piezoelectric material. The reduced elevation dimension of the micro-phased array 2 causes acoustic energy loss, impairing the imaging quality of the ultrasound imaging catheter. Increasing the width of the array element 221 allows for the generation of more acoustic energy while maintaining the same excitation intensity, compensating for the acoustic energy loss caused by the reduced elevation dimension of the array element 221 and ensuring the final imaging quality of the micro-phased array 2. As the size of the micro-phased array 2 decreases, the cross-sectional size of the sheath 1 can also be smaller. This refines the maximum cross-sectional size of the internal ultrasound imaging catheter, reducing damage to blood vessels from the ultra-fine ultrasound imaging catheter.

[0043] In the related technology, the array element 221 is not covered by grouting, so the vibration of one array element 221 will bring aftershocks to the adjacent array element 221 during actual imaging. In order to reduce the interference between different array elements 221, it is necessary to increase the gap size between adjacent array elements 221, which will affect the overall performance of the micro phased array 2.

[0044] In this embodiment, by injecting a highly stable structural adhesive, the array element 221 is completely encapsulated, achieving insulation isolation between the array elements 221, enhanced mechanical support, and optimized acoustic performance. Through the curing effect of the structural adhesive, different array elements 221 can maintain independence even with small gap widths, preventing mutual interference during operation. The structural adhesive can be, but is not limited to, epoxy resin.

[0045] In summary, to avoid damage to delicate blood vessels by the ultrasound imaging catheter and thus reduce the elevation dimension of the miniature phased array 2, a laser cutting process is employed to compensate for the acoustic energy loss caused by the reduced elevation dimension. This laser cutting reduces the cutting gap between adjacent array elements 221, thereby increasing the width of each element 221 and compensating for acoustic energy loss, ensuring good imaging quality for the miniature phased array 2. Furthermore, the injection of a highly stable structural adhesive prevents mutual interference between different array elements 221 during operation.

[0046] In some embodiments, the specific steps for using a laser to cut the piezoelectric material into multiple array elements 221 of equal thickness and width are as follows: S11: A high-power picosecond laser is used to cut the piezoelectric material into array elements 221 of equal width and thickness, and grooves 222 are formed between different array elements 221. S12: Use a low-power picosecond laser to continue refining the groove 222, making the edges of the groove 222 smoother.

[0047] The first step involves rapidly scanning and cutting the piezoelectric material using a high-power picosecond laser. The ultrashort pulse duration of the picosecond laser causes the material to absorb energy and vaporize in a very short time, forming a localized high-temperature, high-pressure plasma, thereby achieving efficient material removal. The high-power laser can penetrate the piezoelectric material in a single pass, forming a continuous cutting trajectory that rapidly cuts the material into initial array elements 221 of equal width and thickness, creating groove structures 222 between the array elements 221.

[0048] A low-power picosecond laser is used to perform a secondary finishing process on the groove 222 formed in the first step. By reducing the energy density, only a small amount of material is removed from the inner wall of the groove 222 and the edges of the array element 221, avoiding excessive cutting that could lead to dimensional deviations in the array element 221. The high-precision focusing of the low-power laser enables point-by-point scanning and finishing of the edges of the array element 221, gradually eliminating burrs, jagged edges, or unevenness, making the edges of the array element 221 smoother.

[0049] A two-step laser cutting process, consisting of "high-power laser coarse cutting + low-power laser fine finishing," achieves high-precision, low-damage cutting of piezoelectric materials. Staged energy control enhances the precision of the piezoelectric material cutting, which in turn improves the geometric accuracy and mechanical integrity of the array element 221, ensuring the consistency of its acoustic performance.

[0050] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. An ultrasound imaging catheter, characterized in that, include: A sheath, the interior of which is provided with a flexible circuit; A miniature phased array is disposed at one end of the sheath and electrically connected to one end of the flexible circuit; the miniature phased array includes a piezoelectric material layer, the piezoelectric material layer includes multiple array elements distributed in an array, each array element is electrically connected to the flexible circuit, and the gap size S between adjacent array elements is 20μm-25μm.

2. The ultrasound imaging catheter according to claim 1, characterized in that, The outer diameter D1 of the sheath is 2.23mm-2.43mm, and / or the inner diameter D2 is 1.9mm-2.1mm.

3. The ultrasound imaging catheter according to claim 1, characterized in that, The width L1 of the cross-section of the flexible circuit is 1.4mm-1.6mm and the height h is 0.1mm-0.3mm, and / or the width L2 of the cross-section of the micro phased array is 1.4mm-1.6mm and the height H is 1.6mm-1.8mm.

4. The ultrasound imaging catheter according to claim 1, characterized in that, The sheath also includes an inner tube stacked together and a braided filament layer, the braided filament layer surrounding the outer periphery of the inner tube, the inner tube having a pipe space, and the flexible circuit being disposed within the pipe space of the inner tube.

5. The ultrasound imaging catheter according to claim 4, characterized in that, The sheath also includes a protective layer material surrounding the side of the braided filament layer opposite to the inner tube.

6. The ultrasound imaging catheter according to claim 4 or 5, characterized in that, The sheath also includes multiple traction ropes, which are embedded in the inner tube and spaced apart circumferentially along the inner tube; the traction ropes extend along the length of the sheath; the ultrasound imaging catheter also includes a handle, one end of the sheath is used to connect to the handle; one end of the traction rope passes through the sheath and is connected to the handle, and the other end is connected to the end of the sheath away from the handle.

7. The ultrasound imaging catheter according to claim 1, characterized in that, The micro phased array further includes a matching layer and a backing layer; the electrode layer includes a ground electrode and a positive electrode, and the piezoelectric material layer is disposed between the ground electrode and the positive electrode; the matching layer is disposed on the side of the ground electrode away from the piezoelectric material; the backing layer is disposed on the side of the positive electrode away from the piezoelectric material.

8. The ultrasound imaging catheter according to claim 7, characterized in that, The matching layer includes a first matching layer and a second matching layer that are bonded to each other, with the second matching layer bonded to the grounding electrode.

9. A method for cutting piezoelectric materials, characterized in that, The method is as follows: S1. Laser cutting: Using a laser to cut the piezoelectric material into multiple array elements of equal width and thickness; S2. Grouting: Injecting structural adhesive to encapsulate the array elements within the structural adhesive; S3. Curing: Allow to stand until the structural adhesive solidifies, and the gaps between the different array elements remain stable.

10. A method for cutting piezoelectric materials according to claim 9, characterized in that, Using a laser to cut piezoelectric materials into multiple array elements of equal thickness and width, including: S11: A high-power picosecond laser is used to cut the piezoelectric material into array elements of equal width and thickness, and grooves are formed between different array elements; S12: Use a low-power picosecond laser to trim the edges of the array elements, making the edges of the grooves smoother.

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