Ultrasonic transducer

Abstract

An ultrasonic transducer comprises a piezoelectric layer with an emitting surface plated with an upper electrode, and the piezoelectric layer is provided with a non-piezoelectric material area; the conductive matching layer is arranged on the front surface of the piezoelectric layer, and a signal pole is led out from the conductive matching layer corresponding to the non-piezoelectric material area; the non-piezoelectric material area is a partition structure formed on the piezoelectric layer, and the partition structure is used for enabling a signal electrode lead-out conductive material to deviate from an emission area of sound waves. According to the piezoelectric array element, the non-piezoelectric material area is arranged on the piezoelectric layer, and the electrode is led out to the position outside the non-working area of the piezoelectric array element through the conductive matching layer, so that the sound performance influence caused by dispensing conductive silver paste is eliminated on the premise that the effective size of the piezoelectric array element is not changed.

Description

Technical Field

[0001] The utility model belongs to the technical field of ultrasonic transducers, in particular to a high-frequency ultrasonic transducer. Background Art

[0002] As an important supplementary method for coronary angiography, intravascular ultrasound (IVUS) improves the accuracy of lesion diagnosis and has important guiding significance for the strategy, stent selection and effect evaluation of percutaneous coronary intervention (PCI).

[0003] The IVUS system usually consists of an ultrasound catheter, a proximal drive module, and an ultrasound imaging system. The ultrasound catheter is mainly composed of an ultrasound transducer, a sheath, and a drive shaft. The ultrasound transducer is mainly used to send and receive ultrasound signals to collect structural information inside the blood vessel. The proximal drive module is mainly responsible for drive control and signal transmission between the ultrasound catheter and the imaging system. The ultrasound imaging system is mainly used for data processing and imaging.

[0004] The miniature ultrasonic transducer installed at the distal end of the IVUS system ultrasound catheter is the core component of IVUS technology. The IVUS system uses an ultrasound catheter to place the ultrasonic transducer inside the blood vessel to send and receive ultrasonic signals, so that it can display the cross-sectional image of the blood vessel and the thickness, lumen size and shape of the vascular wall structure in real time, accurately measure the vascular lumen diameter and cross-sectional area, and even identify lesions such as calcification, fibrosis and lipid pools, and discover early vascular lesions that cannot be displayed by coronary angiography.

[0005] IVUS ultrasonic transducers are usually composed of piezoelectric materials, backing, matching layers and electrode lead-out structures, and there are two types: array type and single element. Array transducers use array elements arranged in a cylindrical structure to achieve 360-degree imaging inside the blood vessel. Single element transducers use a drive shaft to drive the transducer to rotate to achieve 360-degree imaging inside the blood vessel. The smaller the size of the miniature ultrasonic transducer at the distal end of the IVUS ultrasonic catheter, the thinner the blood vessel that can be detected, and the single element transducer can make the size of the transducer very small due to the small number of array elements. Usually, a single element IVUS ultrasonic transducer is a rectangle with a surface length*width less than or equal to 1mm*1mm or a circle with a surface diameter less than or equal to 1mm, and its center frequency is greater than or equal to 20MHz. Due to its small size and high frequency, the processing of each layer of materials and the lead-out of electrodes for IVUS ultrasonic transducers are very difficult.

[0006] The current IVUS single-element ultrasonic transducer is mainly realized through the following process steps:

[0007] Step 1: Grind both sides of the piezoelectric material to a thickness corresponding to the design frequency, usually less than 0.1 mm;

[0008] Step 2: Electrode layers are plated on both sides of the piezoelectric material;

[0009] Step 3: pouring a conductive backing layer on one side of the piezoelectric material;

[0010] Step 4: Slice the piezoelectric material coated with the electrode layer together with the conductive emitting surface backing into the final size;

[0011] Step 5: Lead out electrodes. The ground electrode is led out through the conductive backing and connected to the ground wire of the coaxial cable; the signal electrode is usually led out through the conductive material at the edge of the piezoelectric material surface coating and connected to the signal wire of the coaxial cable.

[0012] Step 6: Deposit a matching layer and a protective layer on the emitting surface of the piezoelectric material.

[0013] The above-mentioned manufacturing process mainly has the following two defects:

[0014] 1) The signal lead-out method occupies part of the transmitting surface, affecting the performance of the transducer.

[0015] The existing process for making transducers is to plate the piezoelectric material with an electrode layer, and then cut the piezoelectric material into the final size. The piezoelectric material of the final size forms a signal electrode plated layer and a grounding plated layer, and the two sides are not conductive. The lead-out electrode process usually uses a method of pouring a conductive backing on one side of the piezoelectric material to lead out the ground electrode, and then coating the other side of the piezoelectric material with conductive glue and extending the conductive glue to the outside of the piezoelectric material to lead out the signal electrode. Since the impedance of the conductive glue material and the subsequently deposited matching layer material are different and the thickness of the conductive glue material on the signal electrode surface is difficult to control, it affects the boundary conditions of the piezoelectric material, resulting in a decrease in transducer performance and a decrease in performance consistency between products.

[0016] 2) The matching layer and protective layer are deposited after the electrode is led out, and the number of matching layers is limited.

[0017] After the piezoelectric material is divided into small rectangular pieces less than 1 mm long and wide and the electrodes are led out, the matching layer cannot be applied to the emitting surface of the piezoelectric material by bonding because the size of the piezoelectric material is too small and the conductive silver glue dots on the signal surface cause the surface to be uneven. In the method of pouring the matching layer, the matching layer material is easy to diffuse around the piezoelectric material during the pouring process, affecting the size of the final transducer, and the thickness of the pouring material is not easy to control. Although the currently commonly used method of depositing the matching layer can control the thickness of the deposited material by controlling the power and deposition time of the deposition equipment, the materials that can be used for deposition are limited, which limits the choice of the transducer matching layer, making it difficult to make a transducer with multiple matching layers. Parylene-C material (a polyparaxylene material) is currently commonly used for deposition, and its acoustic impedance is less than 3MRayl, which is quite different from the acoustic impedance of piezoelectric materials, especially piezoelectric ceramics (usually with an acoustic impedance greater than 30MRayl). Therefore, the sensitivity and bandwidth of IVUS ultrasonic transducers are generally not high. Utility Model Content

[0018] In view of the above technical problems, the purpose of the utility model is to provide an ultrasonic transducer, in which a non-piezoelectric material area is arranged in the piezoelectric layer, and the electrode is led out to a position outside the non-working area of ​​the piezoelectric array element through a conductive matching layer, thereby eliminating the influence of acoustic performance caused by spot coating of conductive silver paste while ensuring that the effective size of the piezoelectric array element remains unchanged.

[0019] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0020] An ultrasonic transducer, comprising:

[0021] A piezoelectric layer with electrodes plated on the emitting surface, wherein the piezoelectric layer has a non-piezoelectric material area;

[0022] A conductive matching layer is arranged on the front surface of the piezoelectric layer, and a signal electrode is led out from the conductive matching layer corresponding to the non-piezoelectric material area.

[0023] In some technical solutions, the non-piezoelectric material area is a partition structure formed on the piezoelectric layer, and the partition structure is used to make the signal electrode lead-out conductive material deviate from the emission area of ​​the sound wave.

[0024] In some technical solutions, the partition structure is a cutout provided on the piezoelectric layer, and the cutout is arranged along the width direction of the piezoelectric layer.

[0025] In some technical solutions, the incision is provided at the end of the piezoelectric layer along the length direction.

[0026] In some technical solutions, one end of the piezoelectric layer along the length direction is piezoelectric material, and the other end is filled with insulating material.

[0027] In some technical solutions, an air gap is provided between the piezoelectric material and the insulating material.

[0028] In some technical solutions, the conductive matching layer has one or more conductive strips arranged along the length direction, or one or more conductive strips arranged along the length direction and the diameter direction and crossing each other.

[0029] In some technical solutions, the configuration of the conductive strips arranged along the diameter direction on the conductive matching layer coincides with the configuration of the non-piezoelectric material area on the piezoelectric layer.

[0030] In some technical solutions, the conductive matching layer is a plurality of layers stacked on top of each other, and at least one pair of conductive strips between adjacent conductive matching layers has an overlapping portion;

[0031] When the signal electrode is finally led out from the outer surface of the conductive matching layer, conductive material exists in the non-piezoelectric material area corresponding to the outermost conductive matching layer;

[0032] When the signal electrode is finally led out from the outer surface of the backing layer on the side of the piezoelectric layer away from the conductive matching layer, conductive material exists in at least the non-piezoelectric material region corresponding to the innermost conductive matching layer.

[0033] In some technical solutions, the conductive matching layer is made by plating conductive layers on both sides of the matching layer; or,

[0034] The conductive matching layer is made of conductive material.

[0035] In some technical solutions, the ultrasonic transducer further includes a backing layer and an electrode lead-out structure.

[0036] The backing layer is arranged on a side of the piezoelectric layer away from the conductive matching layer;

[0037] The electrode lead-out structure includes a signal electrode cable and a ground electrode cable. The signal electrode cable is led out from the non-piezoelectric material area corresponding to the conductive matching layer, and the ground electrode cable is led out from the backing layer.

[0038] In some technical solutions, the ultrasonic transducer has a single piezoelectric array element, the effective working area of ​​the piezoelectric array element is less than 1.0 square millimeter, and the effective working area of ​​the piezoelectric array element is a portion of the corresponding piezoelectric layer excluding the non-piezoelectric material area; and / or,

[0039] The piezoelectric material of the piezoelectric layer is selected from piezoelectric ceramics, piezoelectric single crystals, piezoelectric composite materials or piezoelectric films.

[0040] The utility model adopts the above technical solution to have at least the following beneficial effects:

[0041] 1. The ultrasonic transducer provided by the utility model increases the non-piezoelectric material area of ​​the piezoelectric layer to lead the signal electrode to a position outside the non-working area of ​​the piezoelectric array element through the conductive matching layer. On the one hand, the conductive material of the lead-out electrode is arranged in the non-piezoelectric material area, deviating from the emission area of ​​the sound wave, which can avoid the impedance difference with the matching layer affecting the boundary conditions of the piezoelectric material, improve the imaging resolution and sensitivity of the ultrasonic transducer, and improve the consistency of performance between products; on the other hand, the signal electrode is led out through the conductive matching layer, which can ensure the flatness of the front surface of the piezoelectric layer, facilitate the casting and application of the conductive matching layer, and can be applied to more matching layer materials;

[0042] 2. The ultrasonic transducer provided by the utility model forms a non-piezoelectric material area on the piezoelectric layer by cutting and filling the insulating material, and the non-piezoelectric material area is preferably located at the end of the piezoelectric layer. Such a design facilitates the control of the effective length of the piezoelectric array element in the length direction, thereby eliminating the influence of the acoustic performance caused by the spot coating of the conductive silver paste while ensuring that the effective size of the piezoelectric array element remains unchanged;

[0043] 3. The ultrasonic transducer provided by the utility model has an air gap between the piezoelectric material and the insulating material to enhance the isolation effect between the piezoelectric material area and the non-piezoelectric material area, thereby preventing the piezoelectric material from vibrating laterally and causing the insulating material to vibrate laterally, thereby affecting the piezoelectric performance;

[0044] 4. The ultrasonic transducer provided by the utility model provides a scheme for arranging the conductive strips on the matching layer when the matching layer material itself is non-conductive and the conductive layers are not plated on both sides. Specifically, it can be one or more conductive strips arranged along the length direction of the piezoelectric array element, or one or more conductive strips arranged along the length direction and the diameter direction of the piezoelectric array element and crossing each other; preferably, a conductive layer is plated on the upper and lower surfaces of the matching layer; preferably, when bonding, the conductive strips of the matching layer are placed overlapping with the insulating strips of the piezoelectric material;

[0045] 5. In the ultrasonic transducer provided by the utility model, the signal electrode and the ground electrode can be led out from the same surface or different surfaces of the piezoelectric material; when multiple layers of conductive matching layers are provided, at least one pair of conductive strips between adjacent conductive matching layers has an overlapping portion, and when the signal electrode is finally led out from the outer surface of the conductive matching layer, the non-piezoelectric material region corresponding to the outermost conductive matching layer has conductive material; when the signal electrode is finally led out from the outer surface of the backing layer, at least the non-piezoelectric material region corresponding to the innermost conductive matching layer has conductive material;

[0046] 6. The ultrasonic transducer provided by the utility model is conventionally led out of the signal electrode from the outer surface of the conductive matching layer, and the ground electrode from the conductive backing. They can also be led out interchangeably, that is, the signal electrode is led out of the conductive backing, and the ground electrode is led out of the outer surface of the conductive matching layer, which does not affect the content protected by the patent claims of the utility model;

[0047] 7. The ultrasonic transducer provided by the utility model is a high-frequency ultrasonic transducer having a single piezoelectric array element, the operating frequency of the piezoelectric array element is greater than or equal to 20 MHz, and the area of ​​the working area is less than or equal to 1.0 square millimeter. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings and their marks required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0049] Figure 1 It is a process flow chart of the method for manufacturing the piezoelectric array element according to the embodiment of the utility model;

[0050] Figure 2 One of the cross-sectional views of the piezoelectric array element in the long axis direction described in Example 1 of the present utility model;

[0051] Figure 3 One of the cross-sectional views of the piezoelectric array element in the long axis direction described in Example 1 of the present utility model;

[0052] Figure 4 A top view of the piezoelectric array element described in Example 1 of the present utility model facing the conductive matching layer;

[0053] Figure 5 A cross-sectional view of the piezoelectric array element in the long axis direction as described in Example 2 of the present utility model;

[0054] Figure 6 A top view of the piezoelectric array element described in Example 2 of the present utility model facing the conductive matching layer;

[0055] Figure 7 One of the cross-sectional views of the piezoelectric array element in the long axis direction described in Example 3 of the present utility model;

[0056] Figure 8 One of the cross-sectional views of the piezoelectric array element in the long axis direction described in Example 3 of the present utility model;

[0057] Fig. 9 One of the cross-sectional views of the piezoelectric array element in the long axis direction described in Example 4 of the present utility model;

[0058] Fig.10 This is one of the cross-sectional views of the piezoelectric array element described in Example 4 of the present utility model in the long axis direction.

[0059] The meanings of the symbols in the figure are as follows:

[0060] 10—conductive matching layer, 11—conductive strip;

[0061] 20—piezoelectric layer, 21—piezoelectric material, 22 / 23—insulating material, 24—air gap;

[0062] 30—Backing layer. DETAILED DESCRIPTION

[0063] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the specific implementation methods of the utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0064] In order to simplify the drawings, only the parts related to the utility model are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0065] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0066] In this article, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0067] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0068] In the present invention, the relative position relationship referred to by "front" and "rear" refers to the front end and the rear end of the piezoelectric array element in the direction of sound wave transmission; the azimuth relationship referred to by "length direction" refers to the length direction of the ultrasonic transducer in the catheter; and the "width direction" refers to the diameter direction of the ultrasonic transducer in the catheter.

[0069] In one embodiment, an ultrasonic transducer is provided, including a single piezoelectric array element, wherein the piezoelectric array element is provided with a conductive matching layer, a piezoelectric layer and a backing layer in sequence from front to back, wherein the piezoelectric layer has a non-piezoelectric material area, and electrode layers are provided on both sides of the piezoelectric layer by electroplating. The piezoelectric array element also includes an electrode lead-out structure, specifically including a signal electrode cable and a ground electrode cable, wherein the signal electrode cable is led out from the non-piezoelectric material area corresponding to the conductive matching layer, and the ground electrode cable is led out from the backing layer.

[0070] In this embodiment, the conductive material of the lead-out signal electrode is arranged in the non-piezoelectric material area, away from the emission area of ​​the sound wave, which can avoid the impedance difference with the matching layer affecting the boundary conditions of the piezoelectric material, improve the imaging resolution and sensitivity of the ultrasonic transducer, and improve the consistency of performance between products.

[0071] In the above embodiment, the non-piezoelectric material area is a partition structure formed on the piezoelectric layer, which can be formed by cutting and filling insulating material. In this embodiment, a large piece of piezoelectric material can be cut at intervals larger than the length of the designed piezoelectric array element, thereby maintaining the effective working area of ​​the piezoelectric array element and eliminating the influence of acoustic performance caused by the spot coating of conductive silver paste.

[0072] In some preferred embodiments, the incisions or slits formed by cutting the piezoelectric material are arranged along the width direction of the piezoelectric layer. More preferably, the incisions or slits are arranged at the ends of the piezoelectric layer along the length direction, which can be one end or both ends. Specifically, one end of the piezoelectric layer along the length direction is piezoelectric material, and the other end is filled with insulating material. Such a design makes it easy to control the effective length of the piezoelectric array element in the length direction, thereby eliminating the influence of the acoustic performance caused by the spot coating of conductive silver paste while ensuring that the effective size of the piezoelectric array element remains unchanged.

[0073] Furthermore, an air gap 24 is provided between the piezoelectric material and the insulating material to prevent the piezoelectric material from causing the insulating material to vibrate laterally when vibrating, thereby affecting the piezoelectric performance.

[0074] In the above embodiment, the conductive matching layer can be made by plating conductive layers on both sides of the matching layer; or the material of the matching layer itself is made of conductive material. When the conductive matching layer is not plated with conductive layers on both sides and it is also made of non-conductive material, a conductive strip is provided on the conductive matching layer, and the conductive strip leads the signal electrode corresponding to the non-piezoelectric material area, which can ensure the flatness of the front surface of the piezoelectric layer, facilitate the casting and application of the conductive matching layer, and can be applied to more matching layer materials.

[0075] In some specific embodiments, the conductive matching layer has one or more conductive strips arranged along the length direction, or one or more conductive strips arranged along the length direction and the diameter direction and crossing each other; when one conductive strip is set in the effective area of ​​the piezoelectric array element, it is cut on the large piece of matching layer material with a spacing greater than the size of the piezoelectric array element; when multiple conductive strips are set in the same direction in the effective area of ​​the piezoelectric array element, it is cut on the large piece of matching layer material with a spacing less than the size of the piezoelectric array element.

[0076] Preferably, the positions of the conductive strips arranged along the diameter direction on the conductive matching layer coincide with the positions of the insulating strips on the piezoelectric layer.

[0077] In some preferred embodiments, the conductive matching layer is a plurality of layers stacked on top of each other, and there is an overlapping portion in at least one pair of conductive strips between adjacent conductive matching layers; when the signal electrode is ultimately led out from the outer surface of the conductive matching layer, conductive material exists in the non-piezoelectric material region corresponding to the outermost conductive matching layer; when the signal electrode is ultimately led out from the outer surface of the backing layer on the side of the piezoelectric layer away from the conductive matching layer, conductive material exists in at least the non-piezoelectric material region corresponding to the innermost conductive matching layer.

[0078] The working frequency of the piezoelectric array element provided in this embodiment is greater than or equal to 20 MHz, and the area of ​​the effective working region is less than or equal to 1.0 square millimeter. The effective working region of the piezoelectric array element is the portion of the corresponding piezoelectric layer excluding the non-piezoelectric material region; specifically, the piezoelectric material is selected from piezoelectric ceramics, piezoelectric single crystals, piezoelectric composite materials or piezoelectric films.

[0079] The manufacturing process of the ultrasonic transducer is further described below:

[0080] Electrodes are plated on both sides of the piezoelectric layer, a signal electrode is formed on one side of the emitting surface, and a ground electrode is formed on the other side away from the emitting surface, and the ground electrode is led out from the backing layer of the piezoelectric array element;

[0081] A conductive matching layer is provided to lead the signal electrode to a position outside the working area of ​​the piezoelectric array element.

[0082] A non-piezoelectric material region is provided on the piezoelectric layer, and a signal electrode is led out from the non-piezoelectric material region through a conductive matching layer.

[0083] In this embodiment, the signal electrode is led out from the non-piezoelectric material area through the conductive matching layer, so that the conductive material of the lead-out electrode is arranged in the non-piezoelectric material area, away from the emission area of ​​the sound wave, which can avoid the impedance difference with the matching layer affecting the boundary conditions of the piezoelectric material, improve the imaging resolution and sensitivity of the ultrasonic transducer, and improve the consistency of performance between products; and by leading out the signal electrode through the conductive matching layer, the flatness of the front surface of the piezoelectric layer can be guaranteed, which is beneficial to the casting and application of the conductive matching layer, and can be applicable to more matching layer materials.

[0084] In a preferred embodiment, the non-piezoelectric material area is provided on the piezoelectric layer by cutting the piezoelectric material at intervals greater than the length of the designed piezoelectric array element, and filling the cut with insulating material to form the non-piezoelectric material area. This design facilitates the control of the effective length of the piezoelectric array element in the length direction, thereby eliminating the influence of the spot coating of the conductive silver paste on the acoustic performance while ensuring that the effective size of the piezoelectric array element remains unchanged.

[0085] More preferably, after electrodes are plated on both sides of the piezoelectric layer, the thickness of the piezoelectric material is cut along one side of the piezoelectric material and the formed insulating strip, so that the insulating material is separated from the piezoelectric material, thereby forming an air gap 24.

[0086] In another preferred embodiment, the non-piezoelectric material area is provided on the piezoelectric layer in a specific manner: after the conductive matching layer is completed without cutting grooves in the piezoelectric material, the backing material and the piezoelectric material are cut off along the width direction at the end of the length direction of the piezoelectric array element to form the area, and the cutting depth must be greater than or equal to the total thickness of the backing layer and the piezoelectric layer.

[0087] In another preferred embodiment, the non-piezoelectric material area is provided on the piezoelectric layer in the following manner: the piezoelectric material is cut along the width direction of the piezoelectric element, and the conductive material is filled in the cut. After the conductive matching layer is completed, a groove is cut on one side of the backing layer according to the length dimension of the piezoelectric element, and the insulating material is filled in. The depth of the groove needs to be greater than the sum of the thickness of the backing and the piezoelectric material.

[0088] In the above embodiments, the conductive matching layer can be directly plated with conductive layers on both sides, or a matching layer made of conductive material can be used; or it can be implemented by cutting to form conductive strips; specifically, the manufacturing process of the conductive strips includes: cutting along the length direction of the piezoelectric array element to form one or more conductive strips, or cutting along the length direction and width direction of the piezoelectric array element to form one or more mutually intersecting conductive strips; preferably, the conductive strips of the conductive matching layer overlap with the non-piezoelectric material area of ​​the piezoelectric layer.

[0089] In a preferred embodiment, the conductive matching layer is a plurality of layers stacked on top of each other, and at least one pair of conductive strips has overlapping portions between adjacent conductive matching layers; when the signal electrode is ultimately led out from the outer surface of the conductive matching layer, conductive material exists in the non-piezoelectric material region corresponding to the outermost conductive matching layer; when the signal electrode is ultimately led out from the outer surface of the backing layer on the side of the piezoelectric layer away from the matching layer, conductive material exists in the non-piezoelectric material region corresponding to at least the innermost conductive matching layer.

[0090] In another embodiment, the utility model provides a piezoelectric array element and an ultrasonic transducer thereof, wherein the operating frequency of the piezoelectric array element is greater than or equal to 20 MHz, and the area of ​​the working region is less than or equal to 1.0 square millimeter.

[0091] In order to have a clearer understanding of the technical solution and technical effects of the utility model, the following specific examples are provided:

[0092] Example 1

[0093] See also Figure 1 , the steps for making piezoelectric array elements for ultrasonic transducers are as follows:

[0094] 1. Grinding and gold plating of piezoelectric materials

[0095] Grind the upper and lower surfaces of a large piece of piezoelectric material flat to a thickness greater than the thickness of the design frequency;

[0096] On the surface of the piezoelectric material, cutting is performed in one or more directions at intervals greater than the length of the designed piezoelectric array element, and the cutting depth is less than the thickness of the piezoelectric material;

[0097] Fill the groove with insulating material 22, such as epoxy resin, and after curing, grind the piezoelectric material 21 on both sides until the groove is exposed on each side;

[0098] Electrodes are plated on one side of the piezoelectric material 21, a backing material is poured or applied on the electrode-plated surface, and then the backing layer 30 is polished and flat;

[0099] The piezoelectric material 21 is thinned from the non-electrode-plated surface to a thickness of the designed frequency, and an electrode is plated on the thinned surface.

[0100] 2. Fabrication of Conductive Matching Layer (see Figure 2-4 )

[0101] Cut a large piece of matching layer material with both sides polished flat along the length direction of the piezoelectric array element. When the piezoelectric array element has only one matching layer and the matching layer has only one conductive strip, the cutting interval is greater than or equal to the designed width of the piezoelectric array element, and fill the conductive material in the cut groove;

[0102] The matching layer is thinned on both sides to expose the conductive strip 11 and to the designed thickness, and then the conductive layer can be plated on both sides / or not plated, and bonded to the electrode surface of the piezoelectric material 21; or one side is thinned to expose the conductive strip 11, and the exposed conductive strip surface is plated with a conductive layer / not plated with a conductive layer and bonded to the electrode surface of the piezoelectric material, and then the other side of the matching layer is thinned until the conductive strip 11 is exposed and thinned to the designed thickness, and a conductive layer is plated / not plated. When bonding, it is best that the conductive strip 11 of the conductive matching layer 10 and the insulating strip of the piezoelectric material 21 are placed overlapping, or they can be placed non-overlappingly. When they are placed non-overlappingly, the non-working area of ​​the transducer needs to have a conductive area.

[0103] Making piezoelectric array elements:

[0104] The piezoelectric material 21 bonded with the conductive matching layer 10 is divided into individual piezoelectric array elements. One end of each piezoelectric array element in the length direction is the piezoelectric material 21, and the other end is filled with insulating material 22. The conductive strips 11 of each transducer matching layer are arranged along the length direction of the transducer; the signal electrode and the ground electrode are led out on the same surface or different surfaces of the piezoelectric material.

[0105] Example 2

[0106] See also Figure 5-6 , which is basically the same as the manufacturing process of Example 1, the only difference is:

[0107] The matching layer is cut along the length and width directions of the piezoelectric array element and filled with conductive material. The conductive strips 11 filled along the width direction of the piezoelectric array element are aligned with the insulating strips of the piezoelectric material when the matching layer is bonded to the piezoelectric material.

[0108] Example 3

[0109] See also Figure 7-8 , which is similar to the manufacturing process of Example 1, except that:

[0110] After the piezoelectric material is bonded to the conductive matching layer without cutting grooves, the backing material and the piezoelectric material are cut away along the width direction at one end of the piezoelectric array element in the length direction to expose the conductive strip 11 of the innermost conductive matching layer 10 .

[0111] Example 4

[0112] See also Figure 9-10 After cutting the piezoelectric ceramic according to the scheme of Example 1, fill the groove with conductive material, and then make it according to the process of Example 1 / Example 2. After completing the conductive matching layer, cut a groove on the backing side of the piezoelectric array element according to the length of the piezoelectric array element, and fill it with insulating material 23. The cutting depth is greater than the sum of the thickness of the backing layer 30 and the piezoelectric layer 20. After curing, the large piece of material is divided into the final piezoelectric array element size according to Example 1.

[0113] Example 5

[0114] The piezoelectric array element is equipped with multiple layers of conductive matching layers 10. If the conductive layers 10 are not coated on both sides and the matching layers themselves are not conductive, then at least one pair of conductive strips 11 between each adjacent matching layer has overlapping parts. If the two electrodes of the piezoelectric material are respectively drawn out from the matching surface and the backing surface, the non-working area of ​​the outermost matching layer of the transducer must have conductive material. If both electrodes of the piezoelectric material are drawn out from the backing surface, the first matching layer in the non-working area of ​​the transducer must have conductive material. The optimal solution is that the conductive strips 11 of the matching layer and the insulating strips of the piezoelectric material are located on a short side of the transducer, that is, the non-working area of ​​the transducer.

[0115] Example 6

[0116] In Examples 1 to 5, when a matching layer material itself is conductive, there is no need to cut and then produce conductive strips to produce the matching layer. Instead, the material layer can be directly ground to a designed thickness.

[0117] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model shall be based on the attached claims.

Claims

1. An ultrasonic transducer, characterized in that: include: A piezoelectric layer with electrodes plated on the emitting surface, wherein the piezoelectric layer has a non-piezoelectric material area; A conductive matching layer is provided on the front surface of the piezoelectric layer, and a signal electrode is led out from the conductive matching layer corresponding to the non-piezoelectric material area; A backing layer is arranged on the rear surface of the piezoelectric layer, and the backing layer leads out a grounding electrode of the piezoelectric layer.

2. The ultrasonic transducer according to claim 1, characterized in that: The non-piezoelectric material area is a partition structure formed on the piezoelectric layer, and the partition structure is used to make the signal electrode lead-out conductive material deviate from the emission area of ​​the sound wave.

3. The ultrasonic transducer according to claim 2, characterized in that: The partition structure is a cutout provided on the piezoelectric layer, and the cutout is arranged along the width direction of the piezoelectric layer.

4. The ultrasonic transducer according to claim 3, characterized in that: The cutout is arranged at an end of the piezoelectric layer along a length direction.

5. The ultrasonic transducer according to claim 4, characterized in that: One end of the piezoelectric layer along the length direction is piezoelectric material, and the other end is filled with insulating material.

6. The ultrasonic transducer according to claim 5, characterized in that: An air gap is provided between the piezoelectric material and the insulating material.

7. The ultrasonic transducer according to any one of claims 1 to 6, characterized in that: The conductive matching layer has one or more conductive strips arranged along the length direction, or one or more conductive strips arranged along the length direction and the diameter direction and crossing each other; wherein at least one conductive strip overlaps with the non-piezoelectric material area on the piezoelectric layer.

8. The ultrasonic transducer according to claim 7, characterized in that: The conductive matching layer is a plurality of layers stacked together, and at least one pair of conductive strips between adjacent conductive matching layers has an overlapping portion; When the signal electrode is finally led out from the outer surface of the conductive matching layer, conductive material exists in the non-piezoelectric material area corresponding to the outermost conductive matching layer; When the signal electrode is finally led out from the outer surface of the backing layer on the side of the piezoelectric layer away from the conductive matching layer, conductive material exists in at least the non-piezoelectric material region corresponding to the innermost conductive matching layer.

9. The ultrasonic transducer according to any one of claims 1 to 6, characterized in that: The conductive matching layer is made by plating conductive layers on both sides of the matching layer; or, The conductive matching layer is made of conductive material.

10. The ultrasonic transducer according to claim 1, characterized in that: The ultrasonic transducer has a single piezoelectric array element, the operating frequency of the piezoelectric array element is greater than or equal to 20 MHz, the area of ​​the effective working area of ​​the piezoelectric array element is less than or equal to 1.0 square millimeter, and the effective working area of ​​the piezoelectric array element is the portion of the corresponding piezoelectric layer excluding the non-piezoelectric material area; and / or, The piezoelectric material of the piezoelectric layer is selected from piezoelectric ceramics, piezoelectric single crystals, piezoelectric composite materials or piezoelectric films.

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