Preparation method of conductive backing structure, conductive backing structure and ultrasonic transducer

Abstract

The invention relates to the technical field of ultrasonic detection, and provides a preparation method of a conductive backing structure, which comprises the following steps: S100, placing a conductive material in a concave table of a mold according to a preset arrangement mode; s200, a backing rubber material is poured in the concave table, so that the conductive material in the concave table is immersed in the backing rubber material, and a blank material of the conductive backing structure is obtained after curing and demolding; and S300, the upper surface and the lower surface of the blank material are ground, so that the upper surface and the lower surface are exposed out of the conductive material and reach the design size. The application is no longer limited to only adding noble metal conductive filler to ensure the conductivity of the backing structure; according to the application, a three-dimensional conductive path is constructed in the backing structure by using the conductive material, so that the reliability of electric signal extraction of the ultrasonic transducer is greatly enhanced. Compared with a traditional cutting and filling method, the method has the advantages that a gap layer formed by a pure adhesive does not exist, and the consistency of acoustic performance of the backing structure is ensured. The application also provides a conductive backing structure and an ultrasonic transducer.

Description

Technical Field

[0001] This application relates to the technical field of ultrasonic detection, and particularly relates to a preparation method of a conductive backing structure, a conductive backing structure, and an ultrasonic transducer. Background Art

[0002] Due to its obvious advantages such as non-radiation and real-time dynamic imaging, ultrasonic waves have been widely used in medical imaging diagnosis. The upgrading of ultrasonic transducers is an important part of the development of medical ultrasonic diagnostic systems.

[0003] Piezoelectric ultrasonic probes are applied in various occasions such as medical diagnosis, treatment, and ultrasonic flaw detection. With the demand for efficient and accurate diagnosis, people are also putting forward higher and higher requirements for the performance of ultrasonic imaging devices. Among the various performances of piezoelectric ultrasonic probes, improving the performance of the probe is one of the effective methods to improve the quality of detection images. However, with the development of software and electronic circuit technologies, the performance of ultrasonic probes has increasingly become one of the bottlenecks for improving the image quality of ultrasonic imaging devices.

[0004] An ultrasonic transducer uses the piezoelectric effect of a piezoelectric element to convert the excitation electrical pulse signal of an ultrasonic system into an ultrasonic wave signal to enter a detection object, and then converts the ultrasonic echo signal reflected by the detection object into an electrical signal, thereby realizing the detection of the detection object. The composition of an ultrasonic transducer includes a piezoelectric element, a matching layer, a backing layer, and an electrical path. The backing layer is located on the back of the piezoelectric element, and its function is to absorb the sound energy propagated inside due to the vibration of the piezoelectric element, weaken the ringing effect, prevent the ultrasonic wave from being reflected and then propagated to the piezoelectric element and cause interference to the piezoelectric element; the backing layer also plays a conductive role at the same time, and it connects the electrical signal leads of the piezoelectric element to the system end. Thus, it is required that the backing layer has specific acoustic impedance and acoustic attenuation, and at the same time provide support and a conductive path for the ultrasonic transducer.

[0005] Currently, there are two types of conductive backing materials (backing layers). One type of conductive backing material is generally formed by mixing epoxy resin, curing agent, noble metal conductive particles (such as silver powder, silver-coated metal powder, etc.), solvent, additives, etc. in a certain proportion to form a high-concentration multiphase dispersion system slurry, and then casting and curing to prepare the first type of conductive backing material. However, the conductive particles are expensive, and due to the limited variety of conductive particles, the adjustable range of acoustic impedance is limited.

[0006] When preparing another type of conductive backing material, that is, the second type of conductive backing material, in order to balance the requirements of ultrasonic transducer design for a backing material with a larger adjustable range of acoustic impedance and a backing material with high attenuation, the silver powder in the first type of conductive backing material is usually replaced with non-conductive heavy fillers (such as tungsten powder, tungsten trioxide, etc.), and a certain proportion of lightweight hollow glass microspheres is added to adjust the acoustic impedance of the backing material and increase the acoustic attenuation. Since the above materials are non-conductive, the electrical signals of the piezoelectric element cannot be transmitted to the conductive circuit. This requires that after the material is processed to the designed size, a conductive layer needs to be plated on the surface of the material by methods such as evaporation coating or magnetron sputtering, so as to endow the surface layer of the material with conductivity. However, for the second type of conductive backing material obtained by plating a conductive layer on a material without a conductive path, during the manufacturing process of the ultrasonic transducer, when passing through processing procedures such as bonding / cutting, the gold plating layer on the surface of the conductive backing material will inevitably be damaged, thus having a great adverse impact on the reliability of signal extraction. Summary of the Invention

[0007] In order to solve the above problems, the present application provides a preparation method of a conductive backing structure, a conductive backing structure and an ultrasonic transducer. Compared with the method for preparing the first type of backing material with conductive properties, the present application is no longer limited to only adding precious metal conductive fillers to ensure the conductivity of the backing structure; compared with the method for preparing the second type of backing material with conductive properties, the present application constructs a three-dimensional conductive path in the backing structure using conductive materials, greatly enhancing the reliability of electrical signal extraction of the ultrasonic transducer. Compared with the traditional cutting and filling method, the present application has no gap layer formed by pure adhesive, ensuring the consistency of the acoustic performance of the backing structure. The technical solutions adopted in the present application are as follows:

[0008] A preparation method of a conductive backing structure includes the following steps:

[0009] S100, placing conductive materials in the concave table of the mold according to a preset arrangement manner;

[0010] S200, pouring backing glue in the concave table so that the backing glue covers the conductive materials in the concave table, and obtaining a blank of the conductive backing structure after curing and demolding;

[0011] S300, grinding the upper and lower surfaces of the blank so that the conductive materials are exposed on both the upper and lower surfaces and reach the designed size.

[0012] Compared with the method for preparing the first type of backlining material with conductive properties, the present application is no longer limited to only adding precious metal conductive fillers to ensure the conductivity of the backlining structure; compared with the method for preparing the second type of backlining material with conductive properties, the present application constructs a three-dimensional conductive path in the backlining structure using a conductive material, greatly enhancing the reliability of the electrical signal extraction of the ultrasonic transducer. Compared with the traditional cutting and filling method, the present application has no gap layer formed by pure adhesive, ensuring the consistency of the acoustic performance of the backlining structure.

[0013] In some embodiments, in step S100, the conductive material is a conductive slurry, and the conductive slurry is placed on the bottom surface of the concave platform of the mold by a dispensing machine according to the preset arrangement method.

[0014] Using a dispensing machine to arrange the conductive slurry (conductive material) according to the preset arrangement method has a high arrangement efficiency and an arbitrarily set arrangement shape compared with the method of inserting the conductive material into a pre-fixed groove. In addition, since there is no pre-fixed groove, it is convenient for the demolding of the conductive backlining structure.

[0015] In some embodiments, in step S100, the preset arrangement method of the conductive slurry is one of a dot array, a line array, or a circular array.

[0016] By arranging the conductive slurry in a preset arrangement method of a dot array, a line array, or a circular array, the conductive paths of the three conductive backlining structures prepared by this preparation method can correspond to the piezoelectric wafers in a two-dimensional rectangular array probe, the piezoelectric wafers in a one-dimensional linear array probe, and the piezoelectric wafers in a one-dimensional circular array probe, respectively.

[0017] In some embodiments, in step S100, the conductive material is a strip-shaped sheet, and the bottom of the concave platform is provided with pre-fixed grooves distributed in a line array, and the conductive material is fixed by being inserted into the pre-fixed grooves.

[0018] In some embodiments, in step S100, the conductive material is a solid, its bottom is a whole sheet, and its top is provided with a groove of a preset shape.

[0019] By using a conductive material with a whole sheet at the bottom and a groove of a preset shape at the top, the conductive material can be directly placed on the bottom surface of the concave platform. Compared with the method of inserting the conductive material into a pre-fixed groove, there is no need to set a pre-fixed groove, which is convenient for the demolding of the conductive backlining structure. In addition, the arrangement efficiency of the conductive material in this method is high, and the arrangement shape (achieved by controlling the shape of the groove) can be arbitrarily set.

[0020] In some embodiments, in step S100, the groove on the top of the conductive material is made by milling.

[0021] The grooves are made by milling. Compared with the grooves made by etching or deposition, the milling process is simpler and requires lower costs.

[0022] In some embodiments, in step S100, the conductive material is a graphite pencil lead, the bottom of the recess is provided with pre-fixing grooves distributed in a linear array, and the graphite pencil lead is placed on the notch of the pre-fixing groove along a length direction parallel to the pre-fixing groove.

[0023] Compared with metal as a conductive material, graphite pencil lead is used as a conductive material. Graphite pencil lead can be directly purchased on the market, eliminating the process of processing conductive materials. In addition, graphite pencil lead is cheap, which can reduce the cost of obtaining conductive materials.

[0024] In some embodiments, the mold is made of silicone material.

[0025] By using a mold made of silicone material, the silicone material has elasticity and good deformation recovery performance, which can ensure the convenience of demolding the conductive backing structure blank. In addition, the mold made of silicone material can be reused, reducing production costs.

[0026] On the other hand, the present application provides a conductive backing structure, which is prepared by the aforementioned preparation method.

[0027] On the other hand, the present application also provides an ultrasonic transducer, comprising a piezoelectric layer and the aforementioned conductive backing structure, wherein the conductive backing structure is disposed on the back side of the piezoelectric layer.

[0028] The present application provides a method for preparing a conductive backing structure, a conductive backing structure and an ultrasonic transducer, which have at least one of the following beneficial effects:

[0029] 1. The present application provides a method for preparing a conductive backing structure. Compared with the method for preparing the first type of backing material with conductive properties, the present application is no longer limited to adding only precious metal conductive fillers to ensure the conductivity of the backing structure; compared with the method for preparing the second type of backing material with conductive properties, the present application uses conductive materials to construct a three-dimensional conductive path in the backing structure, so that the reliability of the ultrasonic transducer electrical signal extraction is greatly enhanced. Compared with the traditional cutting and filling method, the present application does not have a gap layer formed by pure adhesive, which ensures the consistency of the acoustic performance of the backing structure.

[0030] 2. The preparation method of a conductive backing structure provided by the present application arranges a conductive slurry (conductive material) by a dispensing machine according to a preset layout method. Compared with the method of inserting the conductive material into a pre-fixed groove, the laying efficiency of the conductive material is high and the layout shape can be set arbitrarily. In addition, since there is no pre-fixed groove, it is convenient for the demolding of the conductive backing structure.

[0031] 3. The preparation method of a conductive backing structure provided by the present application arranges the conductive slurry according to a preset layout method in a dot array, a line array or a circular array, so that the conductive paths of the three conductive backing structures prepared by this preparation method respectively correspond to the piezoelectric wafers in a two-dimensional rectangular array probe, the piezoelectric wafers in a one-dimensional linear array probe, and the piezoelectric wafers in a one-dimensional circular array probe.

[0032] 4. The preparation method of a conductive backing structure provided by the present application uses a conductive material with a whole sheet at the bottom and a groove with a preset shape at the top. The conductive material can be directly placed on the bottom surface of the concave platform. Compared with the method of inserting the conductive material into a pre-fixed groove, there is no need to set a pre-fixed groove, which is convenient for the demolding of the conductive backing structure. In addition, the laying efficiency of the conductive material in this method is high, and the layout shape (realized by controlling the shape of the groove) can be set arbitrarily.

[0033] 5. The preparation method of a conductive backing structure provided by the present application makes the groove by milling. Compared with processing the groove by an etching process or a deposition process, the processing technology of the milling method is simple and the required cost is low.

[0034] 6. The preparation method of a conductive backing structure provided by the present application uses a graphite pencil core as the conductive material. Compared with using a metal as the conductive material, the graphite pencil core can be directly purchased in the market, saving the process of processing the conductive material, and the graphite pencil core is cheap, which can reduce the cost of obtaining the conductive material.

[0035] 7. The preparation method of a conductive backing structure provided by the present application uses a mold made of a silicone material. The silicone material has elasticity and good deformation recovery performance, which can ensure the convenience of demolding the blank of the conductive backing structure. In addition, the mold made of the silicone material can be reused, reducing the production cost. Description of the Drawings

[0036] The following will further illustrate the above characteristics, technical features, advantages and their implementation manners of a preparation method of a conductive backing structure, a conductive backing structure and an ultrasonic transducer in a clear and easy-to-understand manner in combination with the drawings of the preferred embodiments:

[0037] Figure 1It is a flowchart for preparing a conductive backing structure in this application;

[0038] Figure 2 It is a schematic diagram of a conductive backing structure with the conductive material distributed in a dot array. Figure A is a top view of the conductive backing structure, and Figure B is a sectional view of the conductive backing structure along the thickness direction;

[0039] Figure 3 It is a schematic diagram of a conductive backing structure with the conductive material distributed in an annular array. Figure A is a top view of the conductive backing structure, and Figure B is a sectional view of the conductive backing structure along the thickness direction;

[0040] Figure 4 It is a schematic diagram of a conductive backing structure with the conductive material distributed in a line array. Figure A is a top view of the conductive backing structure, and Figure B is a sectional view of the conductive backing structure along the thickness direction;

[0041] Figure 5 It is a schematic diagram of a preparation process of a conductive backing structure. Figure A shows the state where the conductive material is inserted into the pre-fixed groove, and Figure B is a sectional view of the conductive backing structure along the thickness direction;

[0042] Figure 6 It is a schematic diagram of another preparation process of a conductive backing structure. Figure A shows the state where the conductive material (with a flat bottom and a groove with a preset shape at the top) is placed on the concave platform, and Figure B is a sectional view of the conductive backing structure along the thickness direction;

[0043] Figure 7 It is a schematic diagram of a preparation process of a conductive backing structure using a graphite pencil core as the conductive material. Figure A shows the state where the graphite pencil core is placed above the notch of the pre-fixed groove, and Figure B is a sectional view of the conductive backing structure along the thickness direction.

[0044] Explanation of the reference numerals in the drawings:

[0045] Conductive material 1, backing adhesive 2, pre-fixed groove 3, groove 4, mold 5, concave platform 6. Detailed implementation manners

[0046] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will describe the specific implementation manners of this application with reference to the drawings. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other implementation manners can also be obtained.

[0047] For the sake of simplicity of the drawings, only the parts related to the present application are schematically shown in each drawing, and they do not represent the actual structure of the product. In addition, for the sake of simplicity and easy understanding of the drawings, in some drawings, only one of the components with the same structure or function is schematically shown, or only one of them is marked. In this article, "one" not only means "only this one", but also means "more than one" situation.

[0048] It should also be further understood that the term "and / or" used in the description of the present application and the appended claims refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0049] In this article, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0050] In addition, in the description of the present application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0051] Referring to Figures 1-7 , the present application provides a method for preparing a conductive backing structure, including the following steps:

[0052] S100, placing the conductive material 1 in the concave platform 6 of the mold 5 according to a preset arrangement method;

[0053] S200, pouring the backing rubber material 2 into the concave platform 6 so that the backing rubber material 2 covers the conductive material 1 in the concave platform 6, and obtaining a blank of the conductive backing structure after curing and demolding;

[0054] S300, grinding the upper and lower surfaces of the blank so that the upper and lower surfaces both expose the conductive material 1 and reach the designed dimensions.

[0055] It can be understood that compared with the method for preparing the first type of backing material with conductive performance, the present application is no longer limited to only adding precious metal conductive fillers to ensure the conductivity of the backing structure; compared with the method for preparing the second type of backing material with conductive performance, the present application constructs a three-dimensional conductive path in the backing structure with the conductive material 1, greatly enhancing the reliability of the electrical signal extraction of the ultrasonic transducer. Compared with the traditional cutting and filling method, the present application has no gap layer formed by pure adhesive, ensuring the consistency of the acoustic performance of the backing structure.

[0056] The following are four examples to introduce the above preparation method:

[0057] Example 1:

[0058] Refer to Figures 2-4 , a conductive slurry is selected as the conductive material 1 to construct a conductive path. The conductive slurry can be a metal slurry such as silver paste, copper paste or aluminum paste. A three-axis fully automatic dispensing machine is used to dispense the conductive slurry according to a preset layout. When dispensing the conductive slurry, a dispensing needle with a certain diameter is selected, generally a dispensing needle with a diameter of 0.4 mm - 0.8 mm. The specific preparation method is as follows: The conductive slurry is mixed evenly and degassed, then filled into a syringe. Taking the bottom surface of the concave platform 6 of the mold 5 as the base, dispensing is carried out on the base material according to the preset layout. After dispensing, the width and thickness of the conductive path are generally determined by the needle specification and the viscosity of the conductive slurry. If a thicker or wider conductive path is required, it can be achieved by dispensing multiple times.

[0059] After the conductive slurry is cured, the backing rubber material 2 needs to be poured into the concave platform 6. The prepared backing rubber material 2 is mixed and degassed, then filled into a dispensing syringe. A slightly larger diameter dispensing needle can be selected, such as 2.0 mm. Using a three-axis fully automatic dispensing machine, dispensing is carried out on the base material. It should be noted that the thickness of the backing rubber material 2 after dispensing should not be lower than the thickness of the cured conductive slurry. After the backing rubber material 2 is dispensed, it is cured.

[0060] After the backing rubber material 2 is cured, demolding is carried out to obtain a blank of the conductive backing structure. Then, the upper and lower surfaces of the blank are ground to reach the designed dimensions, and at the same time, the conductive material 1 is exposed on both the upper and lower surfaces. Thus, a conductive backing structure with a vertically through conductive path is obtained.

[0061] In this embodiment, the mold 5 is preferably made of silicone material. By using the mold 5 made of silicone material, the silicone material has elasticity and good deformation recovery performance, which can ensure the convenience of demolding the blank of the conductive backing structure. In addition, the mold 5 made of silicone material can be reused, reducing the production cost. It can be understood that the mold 5 can also be made of other materials with elasticity and good deformation recovery performance, such as thermoplastic polyurethane (TPU), polyurethane (PU), etc.

[0062] Theoretically speaking, the conductive slurry can be dispensed into any shape by using a dispensing machine. However, in practical applications, the preset layout of the conductive slurry should match the layout of the piezoelectric wafers in the ultrasonic probe. Specifically, the preset layout of the conductive slurry (conductive material 1) can be dot array, line array or circular array. Refer to Figure 2 , when the conductive slurry (conductive material 1) is in dot array, the conductive path of the prepared conductive backing structure corresponds to the position of the piezoelectric wafers in the two-dimensional rectangular array probe; Refer toFigure 4 When the conductive slurry (conductive material 1) is in a linear array shape, the conductive path of the prepared conductive backing structure corresponds to the position of the piezoelectric chip in the one-dimensional linear array probe; Figure 3 When the conductive slurry (conductive material 1) is in the shape of a ring array, the conductive path of the prepared conductive backing structure corresponds to the position of the piezoelectric chip in the one-dimensional ring array probe.

[0063] Embodiment 2:

[0064] refer to Figure 5 In this embodiment, the conductive material 1 is in the form of a strip sheet, and the bottom of the recess 6 in the mold 5 is provided with pre-fixed grooves 3 distributed in a linear array, and the conductive material 1 is fixed by being inserted into the pre-fixed grooves 3. Specifically, the conductive material 1 can be conductive graphite, metal copper or metal aluminum, or other conductive materials. Conductive graphite blocks, metal copper or metal aluminum are processed into thin sheets with a thickness of about 0.15mm-0.3mm, and then the thin sheets are cut into narrow strips with a width of 0.5mm-0.8mm, so that the strip-shaped sheet-shaped conductive material 1 is obtained. The pre-fixed groove 3 in the recess 6 has a groove depth of about 0.2mm, and the groove width is about 0.05mm wider than the thickness of the conductive material 1. Then, the strip-shaped sheet-shaped conductive material 1 is inserted into the pre-fixed groove 3.

[0065] After the conductive material 1 is fixed, the backing glue 2 needs to be poured into the concave platform 6. The prepared backing glue 2 is mixed and degassed and then loaded into the dispensing syringe. The dispensing needle can be selected with a larger caliber, such as 2.0mm. With the bottom surface of the concave platform 6 of the mold 5 as the base, a three-axis fully automatic dispensing machine is used to dispense glue on the base material. It should be noted that the thickness of the backing glue 2 after dispensing should not be less than the thickness of the conductive slurry after curing. The backing glue 2 is cured after dispensing.

[0066] After the backing rubber 2 is cured, it is demolded to obtain a blank of a conductive backing structure. The upper and lower surfaces of the blank are then ground to reach the designed size, and the conductive material 1 is exposed on both the upper and lower surfaces. Thus, a conductive backing structure with a conductive path running through the upper and lower surfaces is obtained.

[0067] In this embodiment, the mold 5 is preferably made of silicone material. The mold 5 made of silicone material has elasticity and good deformation recovery performance, which can ensure the convenience of demolding the conductive backing structure blank. In addition, the mold 5 made of silicone material can be reused, which reduces the production cost. It is understandable that the mold 5 can also be made of other materials with elasticity and good deformation recovery performance, such as thermoplastic polyurethane (TPU), polyurethane (PU), etc.

[0068] Embodiment three:

[0069] refer toFigure 6 In this embodiment, the conductive material 1 is solid, with a flat bottom and a groove 4 of a preset shape provided at its top. In this embodiment, there is no need to provide a pre-fixing groove 3 in the concave platform 6. The bottom of the conductive material 1 serves as a base to fix the upper (top) structure of the conductive material 1. The bottom structure and the top structure of the conductive material 1 are integrated. The conductive material 1 can be conductive graphite, metallic copper, or metallic aluminum, or other conductive materials. The groove 4 at the top of the conductive material 1 is preferably produced by milling, or can also be produced by an etching process or a deposition process.

[0070] The prepared conductive material 1 is placed in the concave platform 6 of the mold 5, and then the backing rubber material 2 needs to be poured into the concave platform 6. After the prepared backing rubber material 2 is mixed and degassed, it is filled into a dispensing syringe. A relatively large-diameter dispensing needle head can be selected, such as 2.0 mm. Using a three-axis fully automatic dispenser, dispensing is performed on the top surface of the bottom structure of the conductive material 1. It should be noted that the thickness of the backing rubber material 2 after dispensing should not be lower than the thickness after the conductive slurry is cured. After the backing rubber material 2 is dispensed, it is cured.

[0071] After the backing rubber material 2 is cured, demolding is performed to obtain a blank of the conductive backing structure. Then, the upper and lower surfaces of the blank are ground to reach the designed dimensions, and at the same time, the conductive material 1 is exposed on both the upper and lower surfaces. Thus, a conductive backing structure with a vertically through conductive path is obtained.

[0072] In this embodiment, the mold 5 is preferably made of a silicone material. By using a mold 5 made of a silicone material, the silicone material has elasticity and good deformation recovery performance, which can ensure the convenience of demolding the blank of the conductive backing structure. In addition, the mold 5 made of a silicone material can be reused, reducing the production cost. It can be understood that the mold 5 can also be made of other materials with elasticity and good deformation recovery performance, such as thermoplastic polyurethane (TPU), polyurethane (PU), etc.

[0073] Theoretically speaking, the preset shape of the groove 4 can be any shape. However, in practical applications, the shape of the remaining part after the groove 4 is provided at the top of the conductive material 1 should match the arrangement mode of the piezoelectric wafers in the ultrasonic probe. Specifically, the shape of the remaining part at the top of the conductive material 1 can be a dot array shape, a line array shape, or an annular array shape. Refer to Figure 2 When the shape of the remaining part at the top of the conductive material 1 is a dot array shape, the conductive path of the prepared conductive backing structure corresponds to the positions of the piezoelectric wafers in a two-dimensional rectangular array probe; refer to Figure 4 When the shape of the remaining part at the top of the conductive material 1 is a line array shape, the conductive path of the prepared conductive backing structure corresponds to the positions of the piezoelectric wafers in a one-dimensional linear array probe; refer to Figure 3When the shape of the remaining part at the top of the conductive material 1 is an annular array, the conductive paths of the prepared conductive backing structure correspond to the positions of the piezoelectric wafers in the one-dimensional annular array probe.

[0074] Example 4:

[0075] Reference Figure 7 In this embodiment, the conductive material 1 is a graphite pencil lead. The bottom of the concave platform 6 is provided with pre-fixing grooves 3 distributed in a linear array, and the graphite pencil lead is placed on the notch of the pre-fixing groove 3 along the length direction parallel to the pre-fixing groove 3. Specifically, the graphite pencil lead can be 2B or 4B, etc., and the diameter of the graphite pencil lead can be selected from several common specifications on the market, such as 0.5 mm, 0.7 mm, 1.0 mm. The groove depth and groove width of the pre-fixing groove 3 are both about 0.2 mm.

[0076] After the graphite pencil lead is placed, it is necessary to pour the backing rubber material 2 into the concave platform 6. The prepared backing rubber material 2 is mixed and degassed and then filled into a dispensing syringe. A larger nozzle diameter can be selected for the dispensing needle head, such as 2.0 mm. Using the bottom surface of the concave platform 6 of the mold 5 as the base, a three-axis fully automatic dispensing machine is used to perform dispensing on the base material. It should be noted that the thickness of the backing rubber material 2 after dispensing should not be lower than the thickness after the conductive slurry is cured. The backing rubber material 2 is cured after dispensing.

[0077] After the backing rubber material 2 is cured, demolding is performed to obtain the blank of the conductive backing structure. Then, the upper and lower surfaces of the blank are ground to reach the designed dimensions, and at the same time, the conductive material 1 is exposed on both the upper and lower surfaces. Thus, a conductive backing structure with conductive paths penetrating up and down is obtained.

[0078] In this embodiment, the mold 5 is preferably made of silicone material. By using the mold 5 made of silicone material, the silicone material has elasticity and good deformation recovery performance, which can ensure the convenience of demolding the blank of the conductive backing structure. In addition, the mold 5 made of silicone material can be reused, reducing the production cost. It can be understood that the mold 5 can also be made of other materials with elasticity and good deformation recovery performance, such as thermoplastic polyurethane (TPU), polyurethane (PU), etc.

[0079] To reduce the risk of the graphite pencil lead moving when pouring the backing rubber material 2, quick-drying glue can be applied to both ends of the graphite pencil lead for fixation before pouring the backing rubber material 2.

[0080] When the diameter of the graphite pencil lead is D and the exposed width of the graphite on the surface of the conductive backing structure after grinding is required to be L, the maximum thickness dimension d of the obtained conductive backing structure is as follows:

[0081]

[0082] The diameters of common graphite pencil leads on the market are 0.5 mm, 0.7 mm, and 1.0 mm. When it is required that the width of the exposed graphite on the upper and lower surfaces of the conductive backing structure after grinding is not less than 0.2 mm, the maximum thicknesses of the processable conductive backing structures corresponding to the three specifications of graphite pencil leads are 0.3 mm, 0.57 mm, and 0.91 mm, respectively.

[0083] This application provides a conductive backing structure, which is obtained by the foregoing preparation method. Since this conductive backing structure adopts the technical solution of the foregoing embodiment, it has at least the beneficial effects brought by the technical solution of the foregoing embodiment, and will not be elaborated here one by one.

[0084] This application also provides an ultrasonic transducer, including a piezoelectric layer and the foregoing conductive backing structure, and the conductive backing structure is arranged on the back surface of the piezoelectric layer. The specific structure of this conductive backing structure refers to the foregoing embodiment. Since this ultrasonic transducer adopts the technical solution of the foregoing embodiment, it has at least the beneficial effects brought by the technical solution of the foregoing embodiment, and will not be elaborated here one by one.

[0085] It should be noted that the above embodiments can be freely combined according to needs. The above is only the preferred embodiment of this application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of this application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of this application.

Claims

1. A method for preparing a conductive backing structure, characterized in that: The following steps are involved: S100, placing the conductive material in a concave platform of the mold according to a preset arrangement; S200, pouring a backing rubber material into the concave platform so that the backing rubber material covers the conductive material in the concave platform, and obtaining a blank of a conductive backing structure after curing and demoulding; S300, grinding the upper and lower surfaces of the blank material so that the conductive material is exposed on both the upper and lower surfaces and the surfaces are ground to a designed size.

2. The method for preparing a conductive backing structure according to claim 1, characterized in that: In step S100, the conductive material is conductive slurry, and the conductive slurry is placed on the bottom surface of the concave platform of the mold in the preset arrangement by a dispensing machine.

3. The method for preparing a conductive backing structure according to claim 2, characterized in that: In step S100, the preset arrangement of the conductive slurry is one of a dot array, a line array or a ring array.

4. The method for preparing a conductive backing structure according to claim 1, characterized in that: In step S100, the conductive material is in the form of a strip sheet, and the bottom of the recessed platform is provided with pre-fixing grooves distributed in a linear array, and the conductive material is fixed by being inserted into the pre-fixing grooves.

5. The method for preparing a conductive backing structure according to claim 1, characterized in that: In step S100, the conductive material is solid, the bottom of the conductive material is in the shape of a whole sheet, and the top of the conductive material is provided with a groove of a preset shape.

6. The method for preparing a conductive backing structure according to claim 5, characterized in that: In step S100 , the groove on the top of the conductive material is made by milling.

7. The method for preparing a conductive backing structure according to claim 1, characterized in that: In step S100, the conductive material is a graphite pencil lead, the bottom of the concave platform is provided with pre-fixing grooves distributed in a linear array, and the graphite pencil lead is placed on the notch of the pre-fixing groove along a length direction parallel to the pre-fixing groove.

8. A method for preparing a conductive backing structure according to any one of claims 1 to 7, characterized in that: The mold is made of silicone material.

9. A conductive backing structure, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.

10. An ultrasonic transducer, characterized in that: The invention comprises a piezoelectric layer and the conductive backing structure according to claim 9, wherein the conductive backing structure is arranged on the back side of the piezoelectric layer.

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