A matching layer for an ultrasonic transducer and a preparation method thereof

Abstract

An embodiment of this specification provides a matching layer for an ultrasonic transducer and a preparation method. The matching layer includes at least a first component and a second component. Among them, the first component has a first sound velocity, and the second component has a second sound velocity. The first component and the second component are respectively filled in different positions on the same plane of the ultrasonic transducer, so that the sound velocity of the matching layer is distributed in a gradient manner in at least one direction. By filling components with different sound velocities in different positions in the matching layer, the sound velocity of the matching layer is distributed in a gradient manner in at least one direction (such as the elevation angle direction of the matching layer), thereby improving the transmittance of the matching layer to sound waves of different frequencies and increasing the bandwidth of the ultrasonic transducer.

Description

Technical Field

[0001] This specification relates to the medical field, and particularly to a matching layer for an ultrasonic transducer and a preparation method thereof. Background Art

[0002] Medical ultrasonic imaging technology is an important technology in modern medical imaging. The ultrasonic transducer is the core component of a medical ultrasonic imaging device, which can transmit and receive ultrasonic signals. The ultrasonic transducer can generate ultrasonic waves by vibration under the excitation of an electrical signal, and can receive the echo signals generated after the ultrasonic waves propagate to the target organ, and analyze the echo signals to achieve ultrasonic imaging, such as B-mode images.

[0003] For an ultrasonic transducer, the bandwidth is one of its important performances. In the prior art, the bandwidth is often improved by adding a matching layer or using piezoelectric wafers with unequal thicknesses. However, the matching layer is usually set to have the same material and equal thickness structure, resulting in the difficulty of the matching layer to meet the transmission of ultrasonic waves with different frequencies, which limits the bandwidth of the ultrasonic transducer.

[0004] Therefore, it is desired to provide a matching layer that can meet the transmission of ultrasonic waves with different frequencies, so that the ultrasonic transducer has a higher bandwidth. Summary of the Invention

[0005] One embodiment of this specification provides a matching layer for an ultrasonic transducer, which at least includes a first component and a second component. Among them, the first component has a first sound velocity, the second component has a second sound velocity, and the first component and the second component are respectively filled in different positions on the same plane of the ultrasonic transducer, so that the sound velocity of the matching layer is distributed in a gradient manner in at least one direction.

[0006] In some embodiments, the first component and the second component have the same acoustic impedance and / or the same thickness.

[0007] In some embodiments, the first component and the second component have at least one different type of substance; or the first component and the second component have the same type of substance, and at least one of the same type of substances has different proportions, different sizes, and / or different structures in the first component and the second component.

[0008] In some embodiments, the material of the first component and / or the second component includes epoxy resin; the material of the first component and / or the second component further includes at least one of a material in a first sound velocity range, a material in a second sound velocity range, a material in a first density range, and a material in a second density range, the first sound velocity range is less than the second sound velocity range, and the first density range is greater than the second density range.

[0009] In some embodiments, the first sound velocity range is 800 m / s - 2000 m / s, the second sound velocity range is 2800 m / s - 11000 m / s, the first density range is 3 g / cm 3 - 20 g / cm 3 , the second density range is 0.1 g / cm 3 - 0.8 g / cm 3 .

[0010] In some embodiments, the content of the epoxy resin is 100 g; the content of the material in the first sound velocity range is less than or equal to 60 g, or the content of the material in the second sound velocity range is less than or equal to 130 g, or the content of the material in the first density range is less than or equal to 500 g, or the content of the material in the second density range is less than or equal to 20 g.

[0011] In some embodiments, the material in the first sound velocity range includes rubber, the material in the second sound velocity range may include metal oxides and / or inorganic non-metallic compounds with a solid structure, the material in the first density range includes metals, and the material in the second density range includes inorganic non-metallic compounds with a hollow structure and / or plastic expandable microspheres.

[0012] In some embodiments, the material of the first component includes epoxy resin, rubber and metal, the material of the second component includes epoxy resin, metal oxide and inorganic non-metallic compound with a hollow structure, the first sound velocity of the first component is less than the second sound velocity of the second component, and the first component and the second component have the same acoustic impedance.

[0013] In some embodiments, the epoxy resin includes at least one of bisphenol A epoxy resin and bisphenol F epoxy resin; the rubber includes at least one of thermoplastic SBS elastomer, nitrile rubber, butyl rubber, styrene-butadiene rubber, cis-butadiene rubber, ethylene propylene diene monomer rubber, silicone rubber, fluororubber; the metal includes at least one of tungsten, copper, iron, lead; the metal oxide includes at least one of tungsten trioxide, iron oxide, aluminum oxide, zinc oxide, magnesium oxide; the inorganic non-metallic compound includes at least one of glass, ceramics, boron carbide.

[0014] In some embodiments, the range of the first sound velocity or the second sound velocity is 1400 m / s to 3500 m / s.

[0015] One of the embodiments of this specification also provides an ultrasonic transducer. The ultrasonic transducer includes a piezoelectric layer and the above-mentioned matching layer. Among them, the matching layer is arranged between the piezoelectric layer and the object to be measured, and the piezoelectric layer realizes acoustic matching with the object to be measured through the matching layer, and the piezoelectric layer is used to realize the conversion between ultrasonic waves and electric energy.

[0016] In some embodiments, the thickness of the piezoelectric layer includes at least a first thickness and a second thickness, and the first thickness and the second thickness are not equal; the gradient distribution of the sound velocity of the matching layer corresponds to the thickness distribution of the piezoelectric layer.

[0017] In some embodiments, there is an inverse relationship between the gradient distribution of the sound velocity of the matching layer and the thickness distribution of the piezoelectric layer.

[0018] In some embodiments, the first sound velocity of the first component of the matching layer corresponds to the first thickness of the piezoelectric layer, and the second sound velocity of the second component of the matching layer corresponds to the second thickness of the piezoelectric layer; the first thickness is greater than the second thickness, and the first sound velocity is less than the second sound velocity.

[0019] One embodiment of the present specification also provides a method for preparing a matching layer, the method including: configuring a first component and a second component according to the target acoustic impedance and the target sound velocity gradient distribution that the matching layer needs to achieve; respectively disposing the first component and the second component at corresponding preset positions; curing for a preset duration at a preset temperature to obtain the matching layer.

[0020] In some embodiments, the range of the preset temperature is 20°C to 100°C, and the range of the preset duration is 2h to 48h.

[0021] In the present specification, by filling components with different sound velocities in different positions in the matching layer, the sound velocity of the matching layer is distributed in a gradient manner in at least one direction (e.g., the elevation angle direction of the matching layer), thereby improving the transmittance of the matching layer to sound waves of different frequencies and increasing the bandwidth of the ultrasonic transducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present specification will be further described by way of exemplary embodiments, and these exemplary embodiments will be described in detail through the drawings. These embodiments are not restrictive. In these embodiments, the same numbers represent the same structures, where:

[0023] Figure 1 is a schematic structural diagram of an ultrasonic transducer according to some embodiments of the present specification;

[0024] Figure 2 is a three-dimensional structural diagram of a first ultrasonic transducer according to some embodiments of the present specification;

[0025] Figure 3A is a schematic structural diagram of a second ultrasonic transducer according to some embodiments of the present specification;

[0026] Figure 3B is a three-dimensional structural diagram of a second ultrasonic transducer according to some embodiments of the present specification;

[0027] Figure 4It is an exemplary flowchart of a method for preparing a matching layer according to some embodiments of the present specification. Detailed implementation manners

[0028] To more clearly illustrate the technical solutions of the embodiments of the present specification, the accompanying drawings required for the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present specification. For those of ordinary skill in the art, without creative efforts, the present specification can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the figures represent the same structure or operation.

[0029] It should be understood that the "system", "device", "unit" and / or "module" used herein is a way to distinguish different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the said words can be replaced by other expressions.

[0030] As shown in the present specification and the claims, unless the context clearly indicates an exception, words such as "a", "an", "one" and / or "the" are not specifically singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0031] Flowcharts are used in the present specification to illustrate the operations performed by the systems according to the embodiments of the present specification. It should be understood that the operations before or after may not be executed precisely in sequence. On the contrary, the steps can be processed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or one or more steps can be removed from these processes.

[0032] In some embodiments, a medical device may include an image processor and an ultrasound transducer. The ultrasound transducer can convert electrical energy into ultrasonic waves and transmit them into the human body, and convert the ultrasonic waves reflected by the human body (such as echo signals) into electrical signals. The electrical signals corresponding to the echo signals can reflect the state of the internal organs of the human body. The image processor is connected to the ultrasound transducer, and the image processor can receive the electrical signals from the ultrasound transducer. The electrical signals are processed by the image processor to obtain corresponding images (such as B-mode ultrasound images).

[0033] The image processor can be a device that processes the received signals to obtain images. In some embodiments, the image processor may include multiple processing units, and the multiple processing units can process the electrical signals from the ultrasound transducer to obtain the processed images.

[0034] This specification describes an ultrasonic transducer that can utilize the piezoelectric effect to achieve the conversion between ultrasonic waves and electrical energy for application in various business scenarios that utilize ultrasonic waves for measurement. For example, the ultrasonic transducer can be applied in medical imaging devices and can output medical images based on the ultrasonic waves returned by the object to be measured (such as human tissues, etc.). Another example is that the ultrasonic transducer can be applied in underwater monitoring devices to obtain corresponding underwater images based on the ultrasonic waves returned by underwater objects.

[0035] In some embodiments, the ultrasonic transducer may include a matching layer. The matching layer can transmit the ultrasonic waves generated by the ultrasonic transducer to the object to be measured and transmit the ultrasonic waves generated by the human body to the piezoelectric layer. However, the matching layer is usually set to a structure of the same material and equal thickness, resulting in different wavelengths of ultrasonic waves in the matching layer for different frequencies, making it difficult for the matching layer to meet the transmission of ultrasonic waves of different frequencies and limiting the bandwidth of the ultrasonic transducer.

[0036] The matching layer of the ultrasonic transducer provided in this specification is provided with components having different sound velocities, such that the sound velocity of the matching layer is distributed in a gradient manner in at least one direction (such as the elevation angle direction of the matching layer). Since the transmittance of the matching layer is affected by the ratio of the thickness of the matching layer to the wavelength of the ultrasonic wave, and the wavelength of the ultrasonic wave is related to the sound velocity of the matching layer and the frequency of the ultrasonic wave. In the case where the thickness distribution of the piezoelectric layer is unequal, it will result in different frequencies of ultrasonic waves generated in different regions of the piezoelectric layer. Through the gradient distribution of the sound velocity of the matching layer, the wavelengths of ultrasonic waves of different frequencies can be made the same in different components. When the thicknesses of different regions of the matching layer are the same, the ratio of the thickness of the matching layer to the wavelength of the ultrasonic wave in different regions can approach or reach the ideal value, thereby improving the transmittance of the matching layer to ultrasonic waves of different frequencies and increasing the bandwidth of the ultrasonic transducer.

[0037] It should be understood that the application scenarios of the ultrasonic transducer of the present application are merely some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings.

[0038] The following will be combined with Figures 1 - 3B to elaborate in detail on the ultrasonic transducer involved in the embodiments of the present application. It should be noted that the following embodiments are only used to explain the present application and do not constitute a limitation to the present application.

[0039] Figure 1 is a schematic structural diagram of an ultrasonic transducer 100 shown according to some embodiments of this specification. In some embodiments, such as Figure 1As shown, the ultrasonic transducer 100 mainly includes a matching layer 110 and a piezoelectric layer 120. The matching layer 110 is disposed between the piezoelectric layer 120 and the object to be measured. The piezoelectric layer 120 can achieve acoustic matching with the object to be measured through the matching layer 110, and the piezoelectric layer 120 is used to realize the conversion between ultrasonic waves and electrical energy.

[0040] The matching layer 110 is a layered structure that couples (i.e., acoustically matches) the acoustic impedances of adjacent media. In some embodiments, the number of layers of the above-mentioned matching layer 110 can be one or more. The matching layer 110 can be set according to actual needs, and this embodiment does not limit it here. In some embodiments, the matching layer 110 can be disposed on the upper surface of the piezoelectric layer 120 by means of adhesion, welding, nailing, etc. For example, the lower surface of the matching layer 110 and the upper surface of the piezoelectric layer 120 are fixed by adhesion. In some embodiments, the matching layer 110 can also be formed and prepared on the basis of the piezoelectric layer 120, so that the formed matching layer 110 is disposed on the upper surface of the piezoelectric layer 120.

[0041] In some embodiments, the matching layer 110 can include at least one matching member. For example, as Figure 1 shown, the matching layer 110 can include a first matching member 110-1, a second matching member 110-2, and a third matching member 110-3. In some embodiments, the structures, materials, or functions of different matching members can be different. For example, the sound velocities of different matching members can be different.

[0042] The sound velocity refers to the speed at which a sound signal travels in a certain medium. In some embodiments, the sound velocity of the matching layer 110 can be the speed at which ultrasonic waves travel in the matching layer 110. In the case where the matching layer 110 includes multiple matching members, the sound velocity of the matching layer 110 can be the sound velocities of the multiple matching members of the matching layer 110. In some embodiments, the sound velocities of different matching members of the matching layer 110 can be the same or different. For example, as Figure 1 shown, the sound velocity of the first matching member 110-1 and the sound velocity of the third matching member 110-3 can be the same, and the sound velocity of the second matching member 110-2 can be different from the sound velocities of the first matching member 110-1 and the third matching member 110-3, respectively. In some embodiments, different matching members can adopt components with different sound velocities to make the sound velocities of different matching members different.

[0043] The component of the matching layer 110 can be a material with acoustic properties. In some embodiments, the matching layer 110 can include at least a first component and a second component. Among them, the first component has a first sound velocity, the second component has a second sound velocity, and the first component and the second component are filled in different positions on the same plane of the ultrasonic transducer 100, so that the sound velocity of the matching layer 110 is distributed in a gradient manner in at least one direction.

[0044] In some embodiments, the first component and the second component can respectively form a plurality of matching members, so that the sound velocities of the plurality of matching members are different. Exemplarily, as Figure 1 shown, the first matching member 110-1 and the third matching member 110-3 can adopt the first component, and the second matching member 110-2 can adopt the second component, so that the first matching member 110-1 and the third matching member 110-3 have a first sound velocity, and the second matching member 110-2 has a second sound velocity. In some embodiments, the first component and the second component are filled into the same plane of the ultrasonic transducer 100, which can enable the plurality of matching members to be arranged in the same plane of the ultrasonic transducer 100, forming the matching layer 110 of the ultrasonic transducer 100. In some embodiments, the first component and the second component can also be filled into one or more planes of the ultrasonic transducer 100 to prepare one or more matching layers 110.

[0045] In some embodiments, at least one direction can include the length direction and / or the thickness direction of the piezoelectric elements of the piezoelectric layer 120. The length direction of the piezoelectric element can refer to the direction of the first side parallel to the horizontal plane projection of the piezoelectric element, where the horizontal plane projection of the piezoelectric element can include a first side and a second side, and the first side is longer than the second side. The thickness direction of the piezoelectric element can refer to the direction perpendicular to the horizontal plane where the piezoelectric element is located. Exemplarily, at least one direction can include the Y-axis direction (such as the Figure 1 Y direction shown) and / or the Z-axis direction in the three-dimensional coordinate XYZ, where the three-dimensional coordinate takes the intersection point of the first side and the second side of the piezoelectric element as the origin, the width direction of the piezoelectric element as the X-axis, the length direction of the piezoelectric element as the Y-axis, and the thickness direction of the piezoelectric element as the Z-axis coordinate system. For the specific description of at least one direction and the three-dimensional coordinate, reference can be made to other embodiments of this specification, such as Figure 2 and its related description. For the specific description of the piezoelectric element, reference can be made to the related description in the following piezoelectric layer 120.

[0046] The gradient distribution can refer to the stepped or gradual distribution of the sound velocity in one or more directions, such as monotonic decrease or increase, normal distribution, etc. For example, in some embodiments, the gradient distribution of the sound velocity of the matching layer 110 can include the sound velocity monotonically decreasing or increasing from the first side to the second side of the matching layer 110, decreasing or increasing from the center of the matching layer 110 to the peripheral side, etc. Among them, the first side and the second side of the plane can be different sides of the plane, and the first side and the second side can be two corresponding sides. In some embodiments, the direction from the first side to the second side can include the width direction of the matching layer 110 (such as Figure 1in the Y direction shown). In some embodiments, the gradient distribution of the sound velocity of the matching layer 110 may also correspond to the thickness distribution of the piezoelectric layer 120. For specific details, reference may be made to the relevant description of the piezoelectric layer 120, which will not be elaborated here.

[0047] In some embodiments, when the matching layer 110 is multilayer, different matching layers 110 may have the same sound velocity gradient distribution or different sound velocity gradient distributions. Further, at least one of the multiple matching layers 110 may not exhibit a sound velocity gradient distribution.

[0048] It should be noted that since the frequency of the ultrasonic wave is inversely proportional to the thickness of the piezoelectric layer 120, the unequal thickness distribution of the piezoelectric layer 120 will cause the ultrasonic waves generated in different regions of the piezoelectric layer 120 to have different frequencies. Since the sound velocity distribution of the matching layer 110 affects the wavelength and frequency of the ultrasonic wave, the formula is as follows: λ = c / f, where λ represents the wavelength of the ultrasonic wave, c represents the sound velocity of the matching layer, and f represents the frequency of the ultrasonic wave. If a matching layer 110 with a uniform sound velocity distribution is used, it will cause the wavelengths of the corresponding ultrasonic waves to be different when ultrasonic waves with different frequencies propagate in the matching layer 110. Moreover, the ratio of the thickness of the matching layer 110 to the wavelength of the ultrasonic wave can affect the magnitude of the transmittance. For example, when the thickness of the matching layer 110 is an odd multiple of one-quarter wavelength of the ultrasonic wave in the matching layer 110, the ideal transmittance can reach 100%. For ultrasonic waves with different frequencies, if the wavelengths of the ultrasonic waves in the matching layer 110 are not equal, it will cause the ratio of the thickness of each point of the matching layer 110 to the wavelength of the ultrasonic wave to change, resulting in poor acoustic matching of the matching layer and a decrease in the transmittance of the matching layer.

[0049] In some embodiments of this specification, for ultrasonic waves with different frequencies, by filling components with different sound velocities at different positions, the matching layer 110 can have a gradient-distributed sound velocity, so as to be able to control the ultrasonic waves with different frequencies to have the same wavelength in the matching layer 110, thereby improving the transmittance of the matching layer 110 to the ultrasonic wave and increasing the bandwidth of the ultrasonic transducer 100.

[0050] In some embodiments, the first component and the second component in the matching layer 110 may have the same acoustic impedance and / or the same thickness.

[0051] Acoustic impedance can be used to reflect the resistance that sound needs to overcome when passing through a medium. In some embodiments, the acoustic impedance of a component can reflect the resistance that ultrasonic waves need to overcome when passing through the matching layer. For example, the greater the acoustic impedance of a component, the greater the resistance that ultrasonic waves need to overcome when transmitting in the matching layer; conversely, the smaller the acoustic impedance of a component, the smaller the resistance that ultrasonic waves need to overcome when transmitting in the matching layer.

[0052] It should be noted that the difference in acoustic impedance between two objects can reflect whether the two objects are acoustically matched. If the difference in acoustic impedance between two objects exceeds the acoustic impedance threshold, it can be determined that there is acoustic mismatch, and the more energy the ultrasonic wave reflects at the boundary between the two media; conversely, if the difference in acoustic impedance between two objects does not exceed the acoustic impedance threshold, it can be determined that there is acoustic match, and the less energy the ultrasonic wave reflects at the boundary between the two media.

[0053] In some embodiments of the present specification, by designing the first component and the second component to have the same acoustic impedance, acoustic matching can be achieved between different components, and different matching members (such as the first matching member 110-1, the second matching member 110-2, and the third matching member 110-3) in the matching layer 110 can be acoustically matched, reducing the energy consumed when the ultrasonic wave passes through the matching layer 110, thereby improving the transmission effect of the matching layer 110 on the ultrasonic wave.

[0054] In some embodiments, when there are multiple matching layers 110, the different matching layers 110 may have the same acoustic impedance or different acoustic impedances. Exemplarily, the first matching layer may have an acoustic impedance of 8 MRayl - 8.5 Mrayl, the second matching layer may have an acoustic impedance of 4 MRayl - 6 MRayl, and the third matching layer may have an acoustic impedance of 2 MRayl - 3 MRayl. Further, in some embodiments, some of the multiple matching layers 110 may have the same acoustic impedance, and the other part of the matching layers 110 may have different acoustic impedances.

[0055] Since the acoustic impedance of a component can be affected by its density and sound velocity. In some embodiments, when different components of the matching layer 110 have different sound velocities, the density of the component can be adjusted to ensure that different components have the same acoustic impedance. Exemplarily, if the sound velocity of the first component is greater than that of the second component, the density of the first component can be reduced or the density of the second component can be increased so that the first component and the second component can have the same acoustic impedance.

[0056] In some embodiments, different components of the matching layer 110 may have the same thickness, so that the thickness of each point of the matching layer 110 can be equal. For example, as Figure 1 shown, the distance (i.e., thickness) between two points of the matching layer 110 in the Z-axis direction is equal. Exemplarily, the thickness of the matching layer can be at least one of 100 um, 150 um, 200 um, etc.

[0057] In some embodiments of the present specification, by setting the thicknesses of different components of the matching layer 110 to be equal, there is no need to specially process the thickness of the matching layer 110 according to the structure of the piezoelectric layer 120, thereby reducing the processing difficulty of the ultrasonic transducer 100.

[0058] Since the gradient distribution of the sound velocity of the matching layer 110 corresponds to the thickness distribution of the piezoelectric layer 120, in some embodiments, the sound velocity range of the matching layer 110 can be designed according to the structure of the piezoelectric layer 120 (such as the thickness range of different regions of the piezoelectric layer 120). In some embodiments, the range of the first sound velocity of the first component or the second sound velocity of the second component can be 1400 m / s to 3500 m / s. For the specific description of the thickness distribution of the piezoelectric layer 120, reference can be made to the relevant description of the piezoelectric layer 120, which will not be elaborated here.

[0059] It should be noted that the above first sound velocity and second sound velocity are only examples, and do not limit the order of magnitude of the sound velocity of the matching layer 110. It only indicates that different components in the matching layer 110 have different sound velocities, and may also have a third sound velocity, a fourth sound velocity, etc. This embodiment does not make specific limitations on this.

[0060] A component is an inert substance used to adjust the physical and / or chemical properties of a device, such as changing the sound velocity of the device by adjusting properties such as elastic modulus and density. In some embodiments, the component may include inorganic materials and / or organic materials, etc. The sound velocity of the matching layer can be adjusted by changing the type, proportion, size, and / or structure of the materials in the component. Exemplarily, organic materials may include organic substances such as epoxy resin, silicone rubber, fluororubber, nitrile rubber, styrene-butadiene rubber, cis-1,4-polybutadiene rubber, ethylene-propylene-diene monomer rubber, and thermoplastic SBS elastomer plastic expandable microspheres, and inorganic materials may include inorganic non-metallic compounds (such as glass, ceramics), metals (such as tungsten, copper, iron, etc.), and / or metal oxides (such as tungsten trioxide, aluminum trioxide, iron oxide, etc.).

[0061] In some embodiments, different components may include different types of materials and / or different structures, so that different components have different characteristics (such as sound velocity, density, etc.). In some embodiments, the first component and the second component may have at least one different type of substance; or, the first component and the second component may have the same type of substance, and at least one of the same type of substances may have different proportions, sizes, and / or structures in the first component and the second component.

[0062] In some embodiments, introducing one or more different types of substances into the first component and / or the second component can change the sound velocity of the first component and / or the second component. In some embodiments, adjusting the proportion, size, or structure of one or more substances of the same type can also change the sound velocity of the first component and / or the second component. Further, in some embodiments, the proportion, size, or structure of different types of substances in the first component and / or the second component can also be adjusted, thereby further adjusting the sound velocity of the first component and / or the second component.

[0063] Exemplarily, both the first component and the second component may include epoxy resin. In order to make the first component and the second component have different sound velocities, it can be designed to introduce a liquid resin (such as a rubber-like liquid resin) into the first component to reduce the sound velocity of the first component. It can also be designed to introduce a metal oxide filler into the second component to increase the sound velocity of the second component. Moreover, the sound velocity of the first component can be further adjusted by adjusting the proportion of the liquid resin in the first component; or the sound velocity of the second component can be further adjusted by adjusting the proportion, size, and structure of the metal oxide filler in the second component.

[0064] In the embodiments of the present application, through the design of the types, proportions, sizes, structures, etc. of the substances in the components, different components can have different sound velocities, so as to achieve a gradient distribution of the sound velocity of the matching layer 110 and improve the transmittance of the matching layer 110 to ultrasonic waves of different frequencies.

[0065] Since the types and proportions of the substances in the components can also affect the density of the components. In some embodiments, the density of the first component and / or the second component can also be adjusted by adjusting the types and proportions of the substances in the first component and / or the second component, so that the first component and the second component have the same acoustic impedance.

[0066] Exemplarily, when reducing the sound velocity of the first component, a substance with a higher density and a smaller impact on the increase in sound velocity (such as metal, etc.) can be introduced into the first component to increase the density of the first component, so that the first component and the second component have the same acoustic impedance. When increasing the sound velocity of the second component, a substance with a lower density and a smaller impact on the decrease in sound velocity (such as an inorganic non-metallic compound with a hollow structure, etc.) can be introduced into the second component to reduce the density of the second component, so that the first component and the second component have the same acoustic impedance.

[0067] In some embodiments, the first component and the second component can be disposed in the ultrasonic transducer 100 through processes such as casting molding, potting molding, injection molding, etc. to form the matching layer 110. In some alternative embodiments, after the matching layer 110 is prepared by using the above processes, the matching layer 110 can be disposed on the piezoelectric layer 120 by means of bonding, welding, riveting, etc. In some alternative embodiments, the matching layer 110 can be prepared on the upper surface of the piezoelectric layer 120 by using the above processes, so that the matching layer 110 can be disposed in a fitting manner with the piezoelectric layer 120 after being formed. In some embodiments, the matching layer 110 can select different components based on different structures of the piezoelectric layer 120 (such as a gradient distribution of thickness, etc.), so that the sound velocity of the matching layer 110 is in a gradient distribution, so that the matching layer 110 can have a good transmission effect on ultrasonic waves of different frequencies and achieve acoustic matching between piezoelectric layers 120 with different structures and the object to be measured.

[0068] It should be noted that the above first component and second component are only examples, and do not limit the order of magnitude of the components in the matching layer 110. They only indicate that there are different components in the matching layer 110. The matching layer 110 may also have more other components, such as a third component, a fourth component, etc. This embodiment does not make specific limitations on this. In some embodiments, the other components of the matching layer 110 may also have the same properties and functions as the first component and the second component.

[0069] In some embodiments, the sound velocities and / or densities of the first component and the second component can be adjusted by using the different properties of different substances. In some embodiments, the first component and / or the second component may include epoxy resin. The material of the first component and / or the second component further includes at least one of a material in a first sound velocity range, a material in a second sound velocity range, a material in a first density range, and a material in a second density range. The first sound velocity range is less than the second sound velocity range, and the first density range is greater than the second density range.

[0070] Epoxy resin is a thermosetting resin, which has a good transmission effect on ultrasonic waves. In some embodiments, epoxy resin can be used as the substrate of the first component and / or the second component, providing an initial sound velocity for the first component and the second component. Exemplarily, the sound velocity of epoxy resin is 2730 m / s and the density is 1.15 g / cm3.

[0071] Furthermore, in some embodiments, the first sound velocity range can be less than the sound velocity of epoxy resin, and the second sound velocity range can be greater than the sound velocity of epoxy resin. In some embodiments, the first density range can be greater than the density of epoxy resin, and the second density range can be less than the density of epoxy resin. That is to say, adding a material in the first sound velocity range to epoxy resin can be used to reduce the sound velocity of the component, adding a material in the second sound velocity range can be used to increase the sound velocity of the component, adding a material in the first density range can be used to increase the density of the component, and adding a material in the second density range can be used to reduce the density of the component. Exemplarily, in some embodiments, the first sound velocity range is 800 m / s - 2000 m / s, the second sound velocity range is 2800 m / s - 11000 m / s, the first density range is 3 g / cm 3 - 20 g / cm 3 , and the second density range is 0.1 g / cm 3 - 0.8 g / cm 3 .

[0072] In some embodiments, the first component and the second component may be made of the same or different materials among the materials with the first sound velocity range, the materials with the second sound velocity range, the materials with the first density range, and the materials with the second density range. By changing the proportions and contents of the materials in different components, the first component and the second component may have different sound velocities. Further, in some embodiments, the first component and the second component may also have the same acoustic impedance by changing the proportions and contents of the materials with the first density range and the materials with the second density range in different components.

[0073] It should be noted that the materials with the first density range and the materials with the second density range may also have different sound velocities, but they have less influence on the sound velocity compared with the materials with the first sound velocity range and the materials with the second sound velocity range. In some embodiments, the first component and the second component may only include the materials with the first density range and / or the materials with the second density range, and the first component and the second component may have different sound velocities by changing the proportions and contents of the materials with the first density range and / or the materials with the second density range.

[0074] In some embodiments, the materials with the first sound velocity range may include rubber, the materials with the second sound velocity range may include metal oxides and / or inorganic non-metallic compounds with solid structures, the materials with the first density range may include metals, and the materials with the second density range may include inorganic non-metallic compounds with hollow structures and / or plastic expandable microspheres. Since the density of rubber is similar to that of epoxy resin and it has the characteristic of low sound velocity, in some embodiments, rubber has less influence on density and greater influence on sound velocity, and can be used to reduce the sound velocity of the component. For example, the sound velocity of ultrasonic waves in rubber is about 950 m / s to 2400 m / s, so adding rubber to epoxy resin (i.e., the substrate of the component) can reduce the sound velocity of the component.

[0075] In some embodiments, metals have less influence on sound velocity and greater influence on density, and can be used to increase the density of the component. In some embodiments, if the density of the added metal is lower, a larger volume fraction of the metal needs to be added, so that compared with other metals with higher densities, adding a larger volume fraction of a metal with a lower density can further increase the sound velocity of the component. In some embodiments, metal oxides have less influence on density and greater influence on sound velocity, and can be used to increase the sound velocity of the component.

[0076] In some embodiments, inorganic non-metallic compounds with a hollow structure (such as hollow ceramic microspheres, hollow glass microspheres) have a relatively small impact on the sound velocity and a relatively large impact on the density, and can be used to reduce the density of the components. In some embodiments, inorganic non-metallic compounds with a solid structure (such as solid ceramic microspheres, solid boron carbide microspheres, etc.) have a relatively small impact on the density and a relatively large impact on the sound velocity, and can be used to increase the sound velocity of the components.

[0077] Plastic expansion microspheres have a relatively small impact on the sound velocity and a relatively large impact on the density, and the density of the plastic expansion microspheres is less than the density of epoxy resin. In some embodiments, plastic expansion microspheres can be used to reduce the density of the components. For example, the density range of the plastic expansion microspheres is approximately 0.1 g / cm 3 -0.13 g / cm 3 , then adding plastic expansion microspheres to epoxy resin (i.e., the base of the component) can reduce the density of the component.

[0078] In some embodiments, the sound velocity of the component can also be adjusted by adjusting the particle size of the microspheres of the material. As the particle size of the microspheres increases, the increased sound velocity of the material will also become higher and higher. In some embodiments, the form of the metal, metal oxide or inorganic non-metallic compound can be powder or microspheres (also called microbeads), etc., so as to be added to epoxy resin.

[0079] In some embodiments, the material of the first component can include epoxy resin, rubber and metal, and the material of the second component can include epoxy resin, metal oxide and inorganic non-metallic compound with a hollow structure. The first sound velocity of the first component is less than the second sound velocity of the second component, and the first component and the second component have the same acoustic impedance. That is to say, adding rubber with a lower sound velocity and metal with a higher density to epoxy resin can make the first component have the characteristics of low sound velocity and high density. Adding metal oxide with a higher sound velocity and inorganic non-metallic compound with a hollow structure and a lower density to epoxy resin can make the second component have the characteristics of high sound velocity and low density, so that the first sound velocity of the first component is less than the second sound velocity of the second component. Since the acoustic impedance of the component is affected by its density and sound velocity, further, in some embodiments, the first component with low sound velocity and high density and the second component with high sound velocity and low density can have the same acoustic impedance.

[0080] Several exemplary substances of the above types are provided below to describe the specific implementation of the component in detail.

[0081] In some embodiments, the epoxy resin may include at least one of bisphenol A epoxy resin and bisphenol F epoxy resin; the rubber may include at least one of thermoplastic SBS elastomer, nitrile rubber, butyl rubber, styrene-butadiene rubber, cis-1,4-polybutadiene rubber, ethylene-propylene-diene monomer rubber, silicone rubber, and fluororubber; the metal includes at least one of tungsten, copper, iron, and lead; the metal oxide may include at least one of tungsten trioxide, iron oxide, aluminum oxide, zinc oxide, and magnesium oxide; the inorganic non-metallic compound may include at least one of glass, ceramic, and boron carbide.

[0082] In some embodiments, the content of the epoxy resin may be 100 g; the content of the material in the first sound velocity range may be less than or equal to 60 g, or the content of the material in the second sound velocity range may be less than or equal to 130 g, or the content of the material in the first density range may be less than or equal to 500 g, or the content of the material in the second density range may be less than or equal to 20 g. Further, in some embodiments, the content of the rubber may be less than or equal to 60 g, or the content of the metal may be less than or equal to 500 g, the content of the metal oxide may be less than or equal to 130 g, or the content of the solid structure inorganic non-metallic compound may be less than or equal to 130 g, or the content of the hollow structure inorganic non-metallic compound may be less than or equal to 20 g, or the content of the plastic expansion microspheres may be less than or equal to 20 g.

[0083] It should be noted that the substances provided above are only examples, and the components may also include other substances with similar functions and properties. For the specific implementation of the components, reference may be made to other content in this specification, which will not be elaborated here.

[0084] The piezoelectric layer 120 is a layered structure made by using a device with piezoelectric effect. In some implementations, the piezoelectric wafer may be made of one or more materials such as piezoelectric crystals (such as quartz crystal, lithium iodate, etc.), piezoelectric semiconductors (such as cadmium sulfide, zinc oxide, etc.), piezoelectric ceramics, piezoelectric composites, or piezoelectric polymers. The embodiments of the present application are not limited thereto. In some embodiments, the piezoelectric layer 120 may include piezoelectric devices in the shape of wafers, long strips, rods, cylinders, etc.

[0085] In some embodiments, the piezoelectric layer 120 may include one or more piezoelectric wafers, where the piezoelectric wafer may be a device with piezoelectric effect. In some embodiments, as Figure 1 shown, a single piezoelectric wafer may serve as the piezoelectric layer 120. In some embodiments, when there are multiple piezoelectric wafers, the multiple piezoelectric wafers may be stacked to form the piezoelectric layer 120, such as stacking methods like vertical stacking, horizontal arrangement, and multi-array side-by-side.

[0086] In some embodiments, the piezoelectric layer 120 may include one or more piezoelectric elements. A piezoelectric element may be an element in the array structure of the piezoelectric layer 120, which may be divided according to the minimum working unit of the piezoelectric layer 120. In some embodiments, the array structure of the piezoelectric layer 120 may include multi-array side-by-side structures such as a single array, a dual array, a triple array, a quadruple array, a quintuple array, etc. The present application does not specifically limit the number of arrays.

[0087] The above-mentioned array may be a set of piezoelectric elements in the same column stacked along the width direction of the piezoelectric element. In some embodiments, the width direction of the piezoelectric element may refer to the direction parallel to the second side of the horizontal plane projection of the piezoelectric element, where the length of the first side of the horizontal plane projection of the piezoelectric element is longer than that of the second side. Exemplarily, the width direction of the piezoelectric element may be the X-axis direction of the three-dimensional coordinate XYZ (the X direction as shown below Figure 2 ). It should be noted that the stacking direction of the foregoing array is only for illustration, and stacking may also be performed along other directions, which will not be elaborated here.

[0088] In some embodiments, the thickness of the piezoelectric layer 120 may be related to the thickness of the piezoelectric wafer. In some embodiments, when the piezoelectric wafers are stacked in a horizontal arrangement or a multi-array side-by-side manner, the thickness of the piezoelectric layer 120 may be equal to the thickness of the piezoelectric wafer. For example, as Figure 1 shown, the piezoelectric layer 120 includes one piezoelectric wafer, and the thickness of the piezoelectric layer 120 may be equal to the thickness of the piezoelectric wafer.

[0089] In some embodiments, the thickness of the piezoelectric layer 120 may be unequal. The unequal thickness of the piezoelectric layer 120 may mean that the thickness of the piezoelectric layer includes two or more thicknesses. In some embodiments, the thickness of the piezoelectric layer 120 may include a first thickness and a second thickness, and the first thickness is not equal to the second thickness. For example, as Figure 1 shown, the thickness of the middle part of the piezoelectric layer 120 (i.e., the first thickness) may be less than the thickness of the two ends of the piezoelectric layer 120 (i.e., the second thickness). It should be noted that the first thickness and the second thickness do not limit the number of thicknesses of the piezoelectric layer 120, but only indicate that the piezoelectric layer has different thicknesses. The thickness of the piezoelectric layer 120 also includes other thicknesses, such as a third thickness, a fourth thickness, etc., which are not specifically limited in this embodiment.

[0090] In some embodiments, the thickness distribution of the piezoelectric layer 120 may be a gradient distribution. In some embodiments, the thickness distribution of the piezoelectric layer 120 may include that the thickness increases or decreases monotonically from the first side to the second side of the piezoelectric layer 120, increases or decreases from the center of the piezoelectric layer 120 to the peripheral side, etc. Among them, the first side and the second side of the piezoelectric layer 120 may be different sides of the piezoelectric layer 120, and the first side and the second side may be two corresponding sides. In some embodiments, from the first side to the second side may include the length direction of the piezoelectric element (such as Figure 1 the Y direction shown). In some embodiments, the monotonically increasing or decreasing from the first side to the second side of the piezoelectric layer 120 may include a stepwise, linear, etc. monotonically increasing or decreasing. In some embodiments, the increasing or decreasing from the center of the piezoelectric layer 120 to the peripheral side may include a stepwise, linear, curved, parabolic, etc. increasing or decreasing from the center to the peripheral side. In some embodiments, the above thickness distribution of the piezoelectric layer 120 may be set according to actual needs, and this embodiment does not limit it here.

[0091] Since different thicknesses of the piezoelectric layer 120 will result in different frequencies of the generated ultrasonic waves, in some embodiments, the gradient distribution of the sound velocity of the matching layer 110 may correspond to the thickness distribution of the piezoelectric layer 120 to control that ultrasonic waves of different frequencies have the same wavelength in the matching layer 110, thereby improving the transmittance of the matching layer 110 to ultrasonic waves and increasing the bandwidth of the ultrasonic transducer 100.

[0092] In some embodiments, the sound velocity of the matching layer 110 may be inversely proportional to the thickness of the corresponding piezoelectric layer 120. Exemplarily, when the thickness distribution of the piezoelectric layer 120 is monotonically increasing from the first side to the second side of the piezoelectric layer 120, the sound velocity distribution of the matching layer 110 may also be monotonically decreasing from the first side to the second side of the matching layer 110. When the thickness distribution of the piezoelectric layer 120 is monotonically decreasing from the first side to the second side of the piezoelectric layer 120, the sound velocity distribution of the matching layer 110 may also be monotonically increasing from the first side to the second side of the matching layer 110. When the thickness distribution of the piezoelectric layer 120 is increasing or decreasing from the center of the piezoelectric layer 120 to the peripheral side, the sound velocity distribution of the matching layer 110 may also be decreasing or increasing from the center of the matching layer 110 to the peripheral side.

[0093] In some embodiments, the gradient distribution of the sound velocity of the matching layer 110 corresponding to the thickness distribution of the piezoelectric layer 120 may include: the gradient distribution of the sound velocity of the matching layer 110 may have an inverse relationship with the thickness distribution of the piezoelectric layer 120. In some embodiments, the first sound velocity of the first component of the matching layer 110 corresponds to the first thickness of the piezoelectric layer 120, and the second sound velocity of the second component of the matching layer 110 corresponds to the second thickness of the piezoelectric layer 120; wherein, the first thickness is greater than the second thickness, and the first sound velocity is less than the second sound velocity.

[0094] For example, as Figure 1 shown, in the Y-axis direction, the middle part of the piezoelectric layer 120 corresponds to the second matching member 110-2 of the matching layer, the left part of the piezoelectric layer corresponds to the first matching member 110-1 of the matching layer, and the right part of the piezoelectric layer corresponds to the third matching member 110-3 of the matching layer. Among them, the first matching member 110-1 and the third matching member 110-3 may adopt a first component, and the second matching member 110-2 may adopt a second component. As Figure 1 shown, the thickness of each point of the matching layer 110 is equal. In order to make the wavelength of the ultrasonic wave the same in the matching layer 110, the sound velocity of the component in the matching layer 110 may be inversely proportional to the thickness of the piezoelectric layer 120. It can be designed that the first sound velocity of the first component is less than the second sound velocity of the second component, so that the sound velocity of the second matching member 110-2 of the matching layer 110 is higher than the sound velocities of the first matching member 110-1 and the third matching member 110-3 of the matching layer. The second sound velocity c2 of the second matching member 110-2 of the matching layer 110 may correspond to the first thickness of the piezoelectric layer 120, and the first sound velocities c1 of the first matching member 110-1 and the third matching member 110-3 of the matching layer may correspond to the first thickness of the piezoelectric layer, where the first thickness is greater than the second thickness, so that the gradient distribution of the sound velocity of the matching layer 110 decreases from the center to the peripheral side, corresponding to the thickness distribution of the piezoelectric layer 120 increasing from the center to the peripheral side.

[0095] In some embodiments of this specification, the gradient distribution of the sound velocity of the matching layer 110 may be set according to the thickness distribution of the piezoelectric layer 120, so that ultrasonic waves of different frequencies have the same wavelength in the matching layer 110, thereby improving the transmittance of the matching layer 110 to ultrasonic waves and increasing the bandwidth of the ultrasonic transducer 100.

[0096] In some embodiments, the above piezoelectric layer 120 may have different structures and / or compositions. For example, the shape of the piezoelectric layer 120 may include various shapes, etc. The piezoelectric layer 120 may be set according to actual needs, and this embodiment does not limit it here.

[0097] In some embodiments, the thickness of each point of the piezoelectric layer 120 may be the same, and the ultrasonic transducer 100 may realize the emission and reception of ultrasonic waves of different frequencies through the thickness distribution of other structures (such as the high-impedance backing in the following backing layer 130). Correspondingly, in some embodiments, the sound velocity distribution of the matching layer 110 may correspond to the thickness distribution of the high-impedance backing in the backing layer 130, and the specific implementation manner may refer to the following Figures 3A - 3B related description, which will not be elaborated here.

[0098] In some embodiments, as Figure 1As shown, the ultrasonic transducer 100 further includes a backing layer 130, which can be disposed on the side of the piezoelectric layer 120 away from the matching layer 110.

[0099] The backing layer 130 can be a layered structure that absorbs the ultrasonic waves generated by the piezoelectric layer 120 in the direction opposite to the direction of the object to be measured. In some embodiments, the backing layer can include multiple materials, such as a combination of one or more materials like metals, metal oxides, organic materials, etc. In some embodiments, when the piezoelectric wafer of the piezoelectric layer 120 is excited to emit ultrasonic waves, part of the ultrasonic waves propagating in a certain direction enter the backing layer, and strong reflection occurs in the backing layer 130. The strongly reflected ultrasonic waves pass through the piezoelectric layer 120 and propagate forward.

[0100] Figure 2 is a schematic perspective view of the ultrasonic transducer 100 according to some embodiments of the present specification.

[0101] In some embodiments, as Figure 2 shown, the ultrasonic transducer 100 includes a matching layer 110, a piezoelectric layer 120, a backing layer 130, and an acoustic lens 140. In the Z-axis direction, the acoustic lens 140, the matching layer 110, the piezoelectric layer 120, and the backing layer 130 can be stacked from top to bottom.

[0102] In some embodiments, the ultrasonic transducer 100 may further include an acoustic lens 140, which is on the side of the matching layer 110 away from the piezoelectric layer 120. Among them, the acoustic lens 140 is an acoustic element that converges or diverges sound waves. In some embodiments, the acoustic lens 140 can change the direction of ultrasonic wave transmission, that is, refraction occurs, so that the sound waves converge or diverge. In some embodiments, the acoustic lens 140 can converge the ultrasonic waves emitted by the matching layer 110. The present application does not specifically limit the acoustic lens 140.

[0103] Figure 3A is a schematic structural view of the ultrasonic transducer 100 according to some embodiments of the present specification, Figure 3B is a schematic perspective view of the ultrasonic transducer 100 according to some embodiments of the present specification.

[0104] In some embodiments, as Figures 3A - 3B shown, the backing layer 130 can include a first impedance layer 130-1 and a second impedance layer 130-2. The first impedance layer 130-1 and the second impedance layer 130-2 are connected. The first impedance layer 130-1 is connected to the surface of the piezoelectric layer 120 away from the matching layer 110, and the impedance of the first impedance layer 130-1 is higher than that of the second impedance layer 130-2.

[0105] In some embodiments, when the piezoelectric wafer of the piezoelectric layer 120 emits ultrasonic waves under excitation, a part of the ultrasonic waves propagating in a certain direction enter the first impedance layer 130-1, and strong reflection can occur at the interface between the first impedance layer 130-1 and the second impedance layer 130-2. The strongly reflected ultrasonic waves pass through the piezoelectric layer 120 and propagate forward. In some embodiments, the piezoelectric layer 120 and the first impedance layer 130-1 can be regarded as an equivalent oscillator, and the resonance frequency of the oscillator is inversely proportional to the thickness of the first impedance layer 130-1.

[0106] In some embodiments, the backing layer 130 may include multiple materials. For example, the first impedance layer 130-1 may include materials with high impedance and small acoustic attenuation coefficient, such as metals, metal oxides, etc. or mixtures thereof. The second impedance layer 130-2 may include materials with low impedance and large acoustic attenuation coefficient, such as organic materials, etc.

[0107] In some embodiments, the impedance of the first impedance layer 130-1 is 10 to 40 times that of the second impedance layer 130-2. It should be noted that the impedance multiple here is only an example, and the present application does not make specific limitations in this regard. In some embodiments of this specification, through the mutual cooperation of the low-impedance backing structure and the high-impedance structure, different frequencies of ultrasonic wave emission and reception can be achieved by changing the thickness of the high-impedance backing.

[0108] In some embodiments, the thickness of each point of the piezoelectric layer 120 is equal, and the thickness of the first impedance layer 130-1 may be unequal. Exemplarily, the first impedance layer 130-1 may have multiple different thicknesses. In some embodiments, the thickness distribution of the first impedance layer 130-1 may be a gradient distribution. In some embodiments, the thickness distribution of the first impedance layer 130-1 may include that the thickness increases or decreases monotonically from the first side to the second side of the first impedance layer 130-1, increases or decreases from the center of the first impedance layer 130-1 to the peripheral side, etc. Among them, the first side and the second side of the first impedance layer 130-1 may be different sides of the backing layer 130, and the first side and the second side may be two corresponding sides. In some embodiments, the first side to the second side of the first impedance layer 130-1 may include the width direction of the backing layer 130 (such as Figures 3A - 3B the Y direction shown). In some embodiments, the monotonically increasing or decreasing from the first side to the second side of the first impedance layer 130-1 may include stepwise, linear, etc. monotonically increasing or decreasing. In some embodiments, the increasing or decreasing from the center of the first impedance layer 130-1 to the peripheral side may include stepwise, linear, curved, parabolic, etc. increasing or decreasing from the center to the peripheral side. In some embodiments, the above thickness distribution of the first impedance layer 130-1 can be set according to actual needs, and this embodiment does not limit it here.

[0109] In some embodiments, the various structures of the ultrasonic transducer can be connected by bonding. Exemplarily, the matching layer 110, the piezoelectric layer 120, the first impedance layer 130-1, and the second impedance layer 130-2 can be bonded from top to bottom to obtain the ultrasonic transducer 100. In some embodiments, the bonded ultrasonic transducer 100 can be cut one or more times to obtain the cut ultrasonic transducer. In some embodiments, the bonded ultrasonic transducer 100 can be cut for the first time to obtain the cut ultrasonic transducer 100. Exemplarily, as Figure 3B shown, when the cutting direction is along the X-axis direction, the cutting position can be the left and right edges of the middle part of the first impedance layer 130-1. In some embodiments, by cutting the bonded ultrasonic transducer 100, ultrasonic transducers with four arrays, five arrays, etc. can also be obtained. In some embodiments, the cutting direction and the cutting position can be set according to actual needs, and this embodiment does not limit this here.

[0110] In some embodiments, the piezoelectric layer 120 of the broadband planar array ultrasonic transducer can be a piezoelectric wafer. By cutting a piezoelectric wafer, a piezoelectric array of the piezoelectric layer is obtained. The thickness of each point of the piezoelectric layer 120 is equal, and it is a multi-array side-by-side structure, which can avoid multiple processing of the piezoelectric wafer and reduce the damage probability of the piezoelectric wafer.

[0111] In some embodiments, the bonded and cut ultrasonic transducer 100 can be cut for the second time to obtain the ultrasonic transducer 100 after the second cut. Exemplarily, as Figure 3B shown, the cutting direction can be along the Y-axis direction, and the cutting position can be set to be equally spaced. By bonding the acoustic lens 140 on the multi-array ultrasonic transducer after bonding and cutting, the ultrasonic transducer 100 with a broadband planar array is obtained.

[0112] In some embodiments of this specification, as Figure 3B shown, the piezoelectric layer 120 can include a first piezoelectric element 120-1, a second piezoelectric element 120-2, and a third piezoelectric element 120-3. The thickness of the middle part of the first impedance layer 130-1 can be less than the thickness of the left part and the right part of the first impedance layer 130-1. The frequency of the ultrasonic wave when the second piezoelectric element 120-2 bonds to the middle part of the first impedance layer 130-1 is greater than the frequency of the ultrasonic wave when the first piezoelectric element 120-1 and the third piezoelectric element 120-3 bond to the left part and the right part of the first impedance layer 130-1. Thus, the ultrasonic transducer can meet the requirements of transmitting and receiving ultrasonic waves of different frequencies, can improve the longitudinal resolution and sensitivity of the image, and increasing the bandwidth of the ultrasonic transducer is beneficial to harmonic imaging.

[0113] In some embodiments, the piezoelectric layer 120 of the broadband planar array ultrasonic transducer 100 may be a piezoelectric wafer. The piezoelectric array of the piezoelectric layer is obtained by cutting a piezoelectric wafer. The thickness of each point of the piezoelectric layer 120 is equal, and it has a multi-array side-by-side structure, which can avoid multiple processing of the piezoelectric wafer and reduce the damage probability of the piezoelectric wafer. When the thickness of each point of the piezoelectric layer 120 is equal, the thickness of the first impedance layer 130-1 may be unequal, so that the sound signal that the ultrasonic transducer 100 can emit is still a signal wave within a range of frequencies. Correspondingly, in some embodiments, the gradient distribution of the sound velocity of the matching layer 110 is gradient-distributed in at least one direction. By the gradient distribution of the sound velocity of the matching layer, the wavelengths of ultrasonic waves with different frequencies can be the same in the matching layers with different components. When the thicknesses of different regions of the matching layer are the same, the ratio of the thickness of the matching layer in different regions to the wavelength of the ultrasonic wave can be close to or reach the ideal value, thereby improving the transmittance of sound waves with different frequencies and increasing the bandwidth of the ultrasonic transducer.

[0114] In some embodiments, the gradient distribution of the sound velocity of the matching layer 110 corresponds to the thickness distribution of the first impedance layer 130-1. In some embodiments, the thickness distribution of the first impedance layer 130-1 may include that the thickness monotonically increases or decreases from the first side to the second side of the first impedance layer 130-1, increases or decreases from the center of the first impedance layer 130-1 to the peripheral side, etc. Correspondingly, the gradient distribution of the sound velocity of the matching layer 110 may include that the sound velocity monotonically decreases or increases from the first side to the second side of the matching layer 110, decreases or increases from the center of the matching layer 110 to the peripheral side, etc.

[0115] In the embodiments of the present application, by setting the impedance layer, strong reflection can be performed on the backward sound wave, so that the ultrasonic transducer can also send the reflected backward sound wave while emitting the sound signal, thereby increasing the overall intensity of the emitted signal and improving the sensitivity of the transducer (because the intensity of the signal propagating forward increases). Moreover, the thickness distribution of the impedance layer can increase the frequency range where the fundamental wave of the sound signal is located, thereby increasing the bandwidth of the ultrasonic transducer.

[0116] Figure 4 It is an exemplary flowchart of a method for preparing a piezoelectric layer according to some embodiments of this specification.

[0117] Referring to Figure 4 , in some embodiments, the process 400 may include:

[0118] Step 410, configure the first component and the second component according to the target acoustic impedance and the target sound velocity gradient distribution that the matching layer needs to achieve.

[0119] Based on the above description of the ultrasonic transducer 100, the first component and the second component are materials with acoustic properties in the matching layer. In some embodiments, the target acoustic impedance can be the acoustic impedance that the prepared first component and second component are expected to achieve. In some embodiments, the target acoustic impedance can be designed according to the acoustic impedance of the piezoelectric layer and / or the object to be measured, so that the piezoelectric layer can achieve acoustic matching with the object to be measured through the matching layer. Further, in some embodiments, the first component and the second component can also have the same target acoustic impedance, so that acoustic matching can be achieved between different components, reducing the energy consumed when ultrasonic waves pass through the matching layer, thereby improving the transmission effect of the matching layer on ultrasonic waves.

[0120] In some embodiments, the target sound velocity gradient distribution can be the sound velocity gradient distribution that the prepared first component and second component are expected to achieve. In some embodiments, the target sound velocity gradient distribution can be designed according to the thickness gradient distribution of the piezoelectric layer, so that ultrasonic waves of different frequencies have the same wavelength when passing through the matching layer, thereby improving the transmittance of the matching layer to ultrasonic waves and increasing the bandwidth of the ultrasonic transducer. In some embodiments, the target sound velocity gradient distribution can include the sound velocity that the first component and the second component are expected to achieve, and the positions (i.e., the preset positions described below) that the first component and the second component are expected to be set at.

[0121] In some embodiments, the sound velocities of the first component and the second component can be inversely proportional to the thickness of the piezoelectric layer. Exemplarily, when the thickness distribution of the piezoelectric layer is monotonically increasing from the first side to the second side of the piezoelectric layer, the sound velocity distribution of the matching layer can also be monotonically decreasing from the first side of the matching layer (i.e., the position where the first component is located) to the second side (i.e., the position where the second component is located). That is to say, the sound velocity of the first component can be designed to be greater than the sound velocity of the second component.

[0122] In some embodiments, process 400 can further include configuring the first component and the second component according to the target density that the matching layer needs to achieve. The target density can be the density that the prepared first component and second component are expected to achieve. Since the target acoustic impedance is affected by the sound velocity and density, in some embodiments, the target densities of the first component and the second component can be designed according to the target sound velocity gradient distribution and the target acoustic impedance, so that the first component and the second component can also have the same target acoustic impedance.

[0123] In some embodiments, configuring the first component and the second component may include: configuring the types, proportions, sizes, and structures of the substances in the first component and the second component. Exemplarily, it can be configured that both the first component and the second component include: 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoaming agent, and 2 g of silane coupling agent KH560 as the base of the first component and the second component. Then, according to the target sound velocity gradient distribution and the target acoustic impedance, one or more materials are selected from the following various materials and introduced into the first component and the second component: materials in the first sound velocity range with a content less than or equal to 60 g (such as rubber), materials in the second sound velocity range with a content less than or equal to 130 g (such as metal oxides, inorganic non-metallic compounds with solid structures), materials in the first density range with a content less than or equal to 500 g (such as metals), materials in the second density range with a content less than or equal to 20 g (such as inorganic non-metallic compounds with hollow structures, plastic expansion microspheres), so as to adjust the sound velocity and acoustic impedance of the first component and the second component, such that the matching layer can achieve the target sound velocity distribution and the target acoustic impedance.

[0124] It should be noted that the above first component and second component are only examples, and do not limit the order of magnitude of the components in the matching layer. It only indicates that there are different components in the matching layer, and the matching layer may also have more other components, such as a third component, a fourth component, etc. This embodiment does not make specific limitations in this regard.

[0125] Step 420: Respectively configure the first component and the second component at corresponding preset positions.

[0126] In some embodiments, the preset position can be the position where the first component and the second component are expected to be set, and can be configured according to the target sound velocity gradient distribution. In some embodiments, the preset position can be set according to the thickness distribution of the piezoelectric layer. Exemplarily, if the first sound velocity of the first component is less than the second sound velocity of the second component, the first component can be configured at the position corresponding to the piezoelectric layer with a larger thickness, and the second component can be configured at the position corresponding to the piezoelectric layer with a smaller thickness.

[0127] In some embodiments, the first component and the second component can be configured at the corresponding preset positions by means of pouring, filling, injection, etc. Exemplarily, the configured first component and second component can be batch-sealed into a mold, so that the first component and the second component are configured at the preset positions, and the sound velocity gradient distribution of the matching layer can be realized.

[0128] Step 430: Cure for a preset duration at a preset temperature to obtain the matching layer.

[0129] In some embodiments, the preset temperature can be the temperature required for the curing component, and the preset temperature can be set according to the types of substances, proportions, and sizes configured in the first component and the second component. Exemplarily, if epoxy resin is selected as the base in the first component and the second component, the preset temperature of 25°C can be used for curing according to the amount of epoxy resin. In some embodiments, the preset duration can also be set according to the types of substances, proportions, and sizes configured in the first component and the second component.

[0130] In some embodiments, the range of the preset temperature can be 20°C to 100°C, and the range of the preset duration can be 2h to 48h. In some embodiments, the value of the preset duration can be inversely proportional to the value of the preset temperature to ensure that the first component and the second component are fully cured. That is to say, the lower the preset temperature set, the longer the preset duration required; conversely, the higher the preset temperature set, the shorter the preset duration required. Exemplarily, if epoxy resin is selected as the base in the first component and the second component, 100g of epoxy resin can be cured with a preset temperature of 25°C and a preset duration of 24h to prepare a matching layer. 100g of epoxy resin can also be cured with a preset temperature of 60°C and a preset duration of 4h to prepare a matching layer. 100g of epoxy resin can also be cured with a preset temperature of 20°C and a preset duration of 48h to prepare a matching layer.

[0131] In some embodiments, the cured matching layer can be attached to the piezoelectric layer by means of bonding, welding, riveting, etc. In some embodiments, the matching layer can also be directly formed on the basis of the piezoelectric layer, so that the cured matching layer can be disposed on the upper surface of the piezoelectric layer, thereby realizing the function of transmitting ultrasonic waves in the ultrasonic transducer. In some embodiments, after the above step 430, the matching layer can also be ground by a grinding machine to quickly and efficiently adjust the thickness of the matching layer.

[0132] In some embodiments of the present application, the matching layer obtained by curing the first component and the second component can achieve a sound velocity gradient distribution, so that the wavelengths of ultrasonic waves with different frequencies are the same in the matching layer, thereby improving the transmittance of the matching layer to ultrasonic waves and increasing the bandwidth of the ultrasonic transducer. Moreover, the matching layer prepared by the curing method can simplify the process flow of manufacturing the ultrasonic transducer and save costs.

[0133] Table 1 is a corresponding relationship table of the formulations of multiple exemplary components and their acoustic properties. The preparation processes of multiple exemplary components are described below in conjunction with Table 1, and the specific implementation manners of the components of the matching layer are described in detail.

[0134] Table 1 Corresponding relationship table of the formulations of components and their acoustic properties

[0135]

[0136]

[0137] Component A:

[0138] 100 g of epoxy resin and 30 g of epoxy resin curing agent can be added to a flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), 1 g of defoaming agent (not shown in Table 1) is added, and after stirring for a preset stirring duration (e.g., 3 min, 4 min, 5 min, etc.), the epoxy resin is poured into a mold and cured at room temperature for 24 h to obtain an epoxy resin cured product, i.e., Component A. The acoustic performance of Component A is tested, and the sound velocity of Component A is 2730 m / s, the acoustic impedance is 3.14 MRayl, and the density is 1.15 g / cm 3 .

[0139] Component B:

[0140] 100 g of epoxy resin and 30 g of epoxy resin curing agent can be added to a flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), 1 g of defoaming agent and 2 g of silane coupling agent KH560 (not shown in Table 1) are added, and stirred for a preset stirring duration (e.g., 3 min, 4 min, 5 min, etc.). Then 30 g of liquid nitrile rubber is added to the flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), the blended resin is poured into a mold and cured at room temperature for 24 h to obtain a nitrile rubber modified epoxy resin cured product, i.e., Component B. The acoustic performance of Component B is tested, and the sound velocity of Component B is 2130 m / s, the acoustic impedance is 2.63 MRayl, and the density is 1.13 g / cm 3 .

[0141] Component C:

[0142] 100 g of epoxy resin and 30 g of epoxy resin curing agent are added to a flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), 1 g of defoaming agent and 2 g of silane coupling agent KH560 are added, and stirred for a preset stirring duration (e.g., 3 min, 4 min, 5 min, etc.). Then 15 g of silicone rubber A and 15 g of silicone rubber B are added to the flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), the blended resin is poured into a mold and cured at room temperature for 24 h to obtain a silicone rubber modified epoxy resin cured product, i.e., Component C. The acoustic performance of Component C is tested, and the sound velocity of Component C is 1917 m / s, the acoustic impedance is 2.07 MRayl, and the density is 1.08 g / cm 3 .

[0143] As can be seen from the above Component A - Component C, the sound velocities of Component B and Component C are both less than that of Component A, and the acoustic impedances of Component B and Component C are less than that of Component A. That is to say, adding rubber to epoxy resin can reduce the sound velocity of epoxy resin because the rubber component itself has the characteristic of low sound velocity. Compared with epoxy resin (i.e., Component A), modified epoxy resin with reduced sound velocity (i.e., Component B - Component C) can be obtained by introducing rubber, but at the same time, the acoustic impedance of the modified epoxy resin also decreases.

[0144] Component D:

[0145] Add 100 g of epoxy resin and 30 g of epoxy resin curing agent to the flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), add 1 g of defoaming agent and 2 g of silane coupling agent KH560, and stir for a preset stirring time (e.g., 3 min). Then add 30 g of silicone rubber A and 30 g of silicone rubber B to the flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), pour the blended resin into a mold and cure at room temperature for 24 h to obtain a silicone rubber - modified epoxy resin cured product, i.e., Component D. Conduct a sound performance test on Component D, and the sound velocity of Component D is 1503 m / s, the acoustic impedance is 1.58 MRayl, and the density is 1.05 g / cm 3 .

[0146] As can be seen from the above Component A, Component C - Component D, the sound velocity and acoustic impedance of Component D are both less than those of Component C. That is to say, compared with epoxy resin (i.e., Component A), with the increase in the amount of added rubber component, the sound velocity and acoustic impedance of the modified epoxy resin cured product can be further reduced.

[0147] Component E:

[0148] It is possible to add 100 g of epoxy resin and 30 g of epoxy resin curing agent to the flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), add 1 g of defoaming agent and 2 g of silane coupling agent KH560, and stir for a preset stirring time (e.g., 3 min, 4 min, 5 min, etc.). Then add a total of 150 g of tungsten powder with a particle size of 3 μm to the flask in two portions, and finish adding within 10 min. Then add 30 g of silicone rubber A and 30 g of silicone rubber B to the beaker. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), pour the blended resin into a mold and cure at room temperature for 24 h to obtain a modified epoxy resin cured product, i.e., Component E. Conduct a sound performance test on Component E, and the sound velocity of Component E is 1638 m / s, the acoustic impedance is 3.14 MRayl, and the density is 1.92 g / cm 3 .

[0149] From the above components A, D - E, it can be seen that the sound velocity of components D - E is less than that of component A, the density of component D is less than that of component E, and components A and E have the same acoustic impedance. That is to say, adding rubber to epoxy resin (i.e., component A) can reduce the sound velocity, but the acoustic impedance of the modified epoxy resin cured product (i.e., component D) decreases. On the basis of the modified epoxy resin cured product (i.e., component D), tungsten powder with high density can be introduced to adjust the properties of the components, and the modified epoxy resin with increased density (i.e., component E) can be obtained, so that the acoustic impedance of the modified epoxy resin (i.e., component E) is increased. Compared with epoxy resin (i.e., component A), the acoustic impedance of the modified epoxy resin with increased density (i.e., component E) is the same as that of epoxy resin (i.e., component A), while the sound velocity of the modified epoxy resin (i.e., component E) is lower.

[0150] Component F:

[0151] Add 100 g of epoxy resin and 30 g of epoxy resin curing agent to the flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), add 1 g of defoaming agent and 2 g of silane coupling agent KH560, and stir for a preset stirring time (e.g., 3 min, 4 min, 5 min, etc.). Then add a total of 118 g of copper powder with a particle size of 20 μm to the flask in two portions, and finish adding it in 10 min. Then add 30 g of silicone rubber A and 30 g of silicone rubber B to the beaker. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), pour the blended resin into a mold and cure it at room temperature for 24 h to obtain the modified epoxy resin cured product, i.e., component F. Conduct acoustic property tests on component F, and the sound velocity of component F is 1882 m / s, the acoustic impedance is 3.14 MRayl, and the density is 1.67 g / cm 3 .

[0152] From the above components D - F, it can be seen that the acoustic impedance of components E - F is greater than that of component D, and the sound velocity of component F is greater than that of components D - E. That is to say, both tungsten powder and copper powder can increase the acoustic impedance of the modified epoxy resin (i.e., component D). However, due to the low density of copper powder and the large volume fraction of the added copper powder, compared with adding tungsten powder, adding copper powder can increase the sound velocity to a higher level.

[0153] Component G:

[0154] Add 100 g of epoxy resin and 30 g of epoxy resin curing agent into a flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), add 1 g of defoamer and 2 g of KH560, and stir for a preset stirring duration (e.g., 3 min, 4 min, 5 min, etc.). Then add a total of 13 g of hollow ceramic microspheres with a particle size of 50 μm into the flask in two portions. After adding and mixing evenly within 10 min, pour the modified epoxy resin into a mold and cure it at room temperature for 24 h to obtain a modified epoxy resin cured product, namely Component G. Conduct an acoustic property test on Component G, and the sound velocity of Component G is obtained as 2960 m / s, the acoustic impedance is 3.14 MRayl, and the density is 1.06 g / cm 3 。

[0155] From Components A - G, it can be seen that the sound velocity of Component G is greater than that of Component A, the density of Component G is less than that of Component A, and the acoustic impedance of Component G is the same as that of Component A. That is to say, adding hollow ceramic microspheres to epoxy resin (i.e., Component A) can achieve the effects of increasing the sound velocity and keeping the impedance unchanged. The addition of hollow ceramic microspheres can increase the sound velocity on the one hand and reduce the density on the other hand, thus achieving the effects of increasing the sound velocity and keeping the acoustic impedance unchanged.

[0156] Component H:

[0157] Add 100 g of epoxy resin and 30 g of epoxy resin curing agent into a flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), add 1 g of defoamer and 2 g of silane coupling agent KH560, and stir for a preset stirring duration (e.g., 3 min, 4 min, 5 min, etc.). Then add a total of 40 g of aluminum oxide microspheres with a particle size of 50 μm into the flask in two portions. After adding and mixing evenly within 10 min, pour the modified epoxy resin into a mold and cure it at room temperature for 24 h to obtain a modified epoxy resin cured product, namely Component H. Conduct an acoustic property test on Component H, and the sound velocity of Component H is obtained as 3112 m / s, the acoustic impedance is 5.69 MRayl, and the density is 1.83 g / cm 3 。

[0158] Component I:

[0159] Add 100 g of epoxy resin and 30 g of epoxy resin curing agent into a flask. After stirring until evenly mixed (e.g., stirring for 5 min, 10 min, 15 min, etc.), add 1 g of defoaming agent and 2 g of silane coupling agent KH560, and stir for a preset stirring duration (e.g., 3 min, 4 min, 5 min, etc.). Then, add a total of 40 g of aluminum oxide microspheres with a particle size of 150 μm into the flask in two portions. After adding and mixing evenly in 10 min, pour the modified epoxy resin into a mold and cure it at room temperature for 24 h to obtain a cured product of the modified epoxy resin, namely Component I. Conduct a sound performance test on Component I, and the sound velocity of Component I is obtained as 3339 m / s, the acoustic impedance is 6.18 MRayl, and the density is 1.85 g / cm 3 。

[0160] Component J:

[0161] Add 100 g of epoxy resin and 30 g of epoxy resin curing agent into a flask. After stirring until evenly mixed, add 1 g of defoaming agent and 2 g of silane coupling agent KH560, and stir for a preset stirring duration (e.g., 3 min, 4 min, 5 min, etc.). Then, add 40 g of aluminum oxide microspheres and 14 g of hollow glass microspheres with a density of 0.15 g / cm 3 into the flask in two portions. After adding and mixing evenly in 10 min, pour the modified epoxy resin into a mold and cure it at room temperature for 24 h to obtain a cured product of the modified epoxy resin, namely Component J. Conduct a sound performance test on Component J, and the sound velocity of Component J is obtained as 3143 m / s, the acoustic impedance is 3.14 MRayl, and the density is 1.00 g / cm 3 。

[0162] From Component H to Component J, it can be seen that as the particle size of the microspheres increases, the increased sound velocity also becomes higher. By adding low-density hollow glass microspheres, compared with epoxy resin (i.e., Component A), a modified epoxy resin with an impedance of 3.14 MRayl (the same as the acoustic impedance of Component A) and a high sound velocity (i.e., Component J) can be obtained.

[0163] Component K - Component L:

[0164] Component K includes 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoaming agent, 2 g of silane coupling agent KH560, and 65 g of aluminum oxide microspheres with a particle size of 5 μm - 100 μm. Conduct a sound performance test on Component K, and the sound velocity of Component K is obtained as 3055 m / s, the acoustic impedance is 4.67 MRayl, and the density is 1.53 g / cm 3 。

[0165] Component L includes: 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoamer, 2 g of silane coupling agent KH560, and 30 g of aluminum oxide microspheres with a particle size of 5 μm - 100 μm. The acoustic performance of Component L was tested, and the sound velocity of Component L was obtained as 2874 m / s, the acoustic impedance was 3.82 MRayl, and the density was 1.33 g / cm 3 The preparation methods of Component K and Component L are similar to those of the above-mentioned Component H - Component I, and will not be elaborated here.

[0166] It can be seen from Component H - Component I and Component K - Component L that as the content of metal oxide in the component increases, the sound velocity of the component will also increase. The sound velocities of the first component and the second component can be made different by adjusting the content of metal oxide in the first component and the second component.

[0167] The following also provides the formulations and acoustic performances of several exemplary components. The preparation processes are similar to those of the above-mentioned Component A - Component J and will not be elaborated here.

[0168] Component M:

[0169] Component M includes 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoamer, 2 g of silane coupling agent KH560, and 500 g of tungsten powder. The acoustic performance of Component M was tested, and the sound velocity of Component M was obtained as 1719 m / s, the acoustic impedance was 7.64 MRayl, and the density was 4.45 g / cm 3 It can be seen from Component A and Component M that adding tungsten powder alone to epoxy resin can significantly increase the acoustic impedance and density of epoxy resin and reduce the sound velocity of epoxy resin.

[0170] Component N:

[0171] Component N includes 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoamer, 2 g of silane coupling agent KH560, and 20 g of hollow glass microspheres with a density of 0.15 g / cm 3 The acoustic performance of Component N was tested, and the sound velocity of Component N was obtained as 2526 m / s, the acoustic impedance was 1.57 MRayl, and the density was 0.62 g / cm 3 It can be seen from Component A and Component N that adding hollow glass microspheres alone to epoxy resin can significantly reduce the density of epoxy resin and reduce the sound velocity and acoustic impedance of epoxy resin.

[0172] Component O:

[0173] Component O includes 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoamer, 2 g of silane coupling agent KH560, 30 g of nitrile, and 130 g of aluminum oxide microspheres. The acoustic performance of Component O was tested, and the sound velocity of Component O was found to be 2791 m / s, the acoustic impedance was 4.97 MRayl, and the density was 1.78 g / cm 3 .

[0174] Component P:

[0175] Component P includes 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoamer, 2 g of silane coupling agent KH560, 30 g of silicone rubber A, 30 g of silicone rubber B, and 13 g of hollow ceramic microspheres with a particle size of 50 μm. The acoustic performance of Component P was tested, and the sound velocity of Component P was found to be 1816 m / s, the acoustic impedance was 1.80 MRayl, and the density was 0.99 g / cm 3 .

[0176] Component Q:

[0177] Component Q includes 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoamer, 2 g of silane coupling agent KH560, 30 g of silicone rubber A, 30 g of silicone rubber B, 50 g of tungsten, and 20 g of aluminum oxide microspheres. The acoustic performance of Component Q was tested, and the sound velocity of Component Q was found to be 2259 m / s, the acoustic impedance was 3.14 MRayl, and the density was 1.39 g / cm 3 .

[0178] Component R:

[0179] Component R includes 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoamer, 2 g of silane coupling agent KH560, 30 g of silicone rubber A, 30 g of silicone rubber B, 50 g of tungsten, and 10 g of hollow glass microspheres with a density of 0.15 g / cm 3 The acoustic performance of Component R was tested, and the sound velocity of Component R was found to be 2152 m / s, the acoustic impedance was 2.15 MRayl, and the density was 1.00 g / cm 3 .

[0180] Component S:

[0181] Component S includes 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoamer, 2 g of silane coupling agent KH560, 30 g of silicone rubber A, 30 g of silicone rubber B, 65 g of aluminum oxide microspheres, and 10 g of hollow glass microspheres with a density of 0.15 g / cm 3 The acoustic performance of Component S was tested, and the sound velocity of Component S was found to be 2427 m / s, the acoustic impedance was 2.45 MRayl, and the density was 1.01 g / cm 3。

[0182] Component T:

[0183] Component T includes 100 g of epoxy resin, 30 g of epoxy resin curing agent, 1 g of defoaming agent, 2 g of silane coupling agent KH560, 30 g of silicone rubber A, 30 g of silicone rubber B, 50 g of tungsten powder, 65 g of aluminum oxide microspheres, and 10 g of hollow glass microspheres with a density of 0.15 g / cm 3 The acoustic performance of Component T was tested, and the sound velocity of Component T was obtained as 2553 m / s, the acoustic impedance was 3.04 MRayl, and the density was 1.19 g / cm 3 。

[0184] In some embodiments, one or more combinations can be selected from Component B - Component T as the first component and the second component, so that the first component and the second component have different sound velocities to achieve the target sound velocity distribution of the matching layer. Further, in some embodiments, one or more combinations can be selected from Component E, Component F, Component G, Component J, and Component Q as the first component and the second component, so that the first component and the second component have different sound velocities and the same acoustic impedance to achieve the target sound velocity distribution and target acoustic impedance of the matching layer.

[0185] It should be noted that the acoustic performance parameters of the components in Table 1 above are only for illustration, and the present application does not specifically limit the acoustic performance parameters of the components in Table 1 above.

[0186] The beneficial effects that the embodiments of this specification may bring include, but are not limited to: by filling components with different sound velocities in different positions, the sound velocity of the formed matching layer is distributed in a gradient manner in at least one direction (such as the elevation angle direction of the matching layer), thereby improving the transmittance of the matching layer to sound waves of different frequencies and increasing the bandwidth of the ultrasonic transducer.

[0187] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only an example and does not constitute a limitation to this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are proposed in this specification, so such modifications, improvements, and corrections still belong to the spirit and scope of the exemplary embodiments of this specification.

[0188] In the meantime, this specification uses specific terms to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0189] In addition, unless clearly stated in the claims, the order of the processing elements and sequences, the use of numerical and alphabetical characters, or the use of other names in this specification are not used to limit the order of the processes and methods in this specification. Although some currently useful embodiments of the invention are discussed through various examples in the above disclosure, it should be understood that such details only serve the purpose of illustration. The appended claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that conform to the essence and scope of the embodiments of this specification. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only through software solutions, such as installing the described system on existing servers or mobile devices.

[0190] Similarly, it should be noted that, in order to simplify the expression of the disclosure in this specification and thus help the understanding of one or more embodiments of the invention, in the previous description of the embodiments of this specification, sometimes multiple features are grouped into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the subject of this specification are more than those mentioned in the claims. In fact, the features of the embodiments are fewer than all the features of the individual embodiments disclosed above.

[0191] In some embodiments, numbers describing the components and the quantity of attributes are used. It should be understood that such numbers used for the description of the embodiments are modified by the modifiers "about", "approximate", or "substantially" in some examples. Unless otherwise stated, "about", "approximate", or "substantially" indicate that the said numbers allow a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and the claims are approximate values, and such approximate values can change according to the characteristics required by individual embodiments. In some embodiments, the numerical parameters should consider the specified significant digits and adopt the method of retaining the general number of digits. Although the numerical ranges and parameters used in some embodiments of this specification to confirm the breadth of their ranges are approximate values, in specific embodiments, such numerical settings are as precise as possible within the feasible range.

[0192] For each patent, patent application, patent application publication, and other materials cited in this specification, such as articles, books, specifications, publications, documents, etc., their entire contents are hereby incorporated by reference into this specification. This excludes application history files that are inconsistent with or conflict with the content of this specification, as well as files that limit the broadest scope of the claims of this specification (currently or subsequently appended to this specification). It should be noted that if there are any inconsistencies or conflicts between the descriptions, definitions, and / or uses of terms in the supplementary materials of this specification and the content described in this specification, the descriptions, definitions, and / or uses of terms in this specification shall prevail.

[0193] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this specification may be considered to be consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly presented and described in this specification.

Claims

1. A matching layer for an ultrasonic transducer, comprising at least a first component and a second component, wherein: The first component has a first sound velocity; The second component has a second sound velocity; The first component and the second component are respectively filled in different positions on the same plane of the ultrasonic transducer, so that the sound velocity of the matching layer is distributed in a gradient manner in at least one direction; the at least one direction at least includes the length direction of the piezoelectric elements of the piezoelectric layer of the ultrasonic transducer; The first sound velocity of the first component is less than the second sound velocity of the second component, and the first component and the second component have the same acoustic impedance; The material of the first component includes epoxy resin, a material within a first sound velocity range, and a material within a first density range; The material of the second component includes epoxy resin, a material within a second sound velocity range, and a material within a second density range; The first sound velocity range is less than the sound velocity of the epoxy resin, and the second sound velocity range is greater than the sound velocity of the epoxy resin; The first density range is greater than the density of the epoxy resin, and the second density range is less than the density of the epoxy resin.

2. The matching layer according to claim 1, wherein: The first component and the second component have the same type of material, and at least one of the same type of materials has different proportions, different sizes, and / or different structures in the first component and the second component.

3. The matching layer according to claim 1, wherein: The first sound velocity range is 800 m / s - 2000 m / s, the second sound velocity range is 2800 m / s - 11000 m / s, and the first density range is 3 g / cm 3 - 20 g / cm 3 , the second density range is 0.1 g / cm 3 - 0.8 g / cm 3 .

4. The matching layer according to claim 1, wherein: The content of the epoxy resin is 100 g; The content of the material within the first sound velocity range is less than or equal to 60 g, or the content of the material within the second sound velocity range is less than or equal to 130 g, or the content of the material within the first density range is less than or equal to 500 g, or the content of the material within the second density range is less than or equal to 20 g.

5. The matching layer according to claim 1, wherein: The material within the first sound velocity range includes rubber, the material within the second sound velocity range includes metal oxides and / or solid - structured inorganic non - metallic compounds, the material within the first density range includes metals, and the material within the second density range includes hollow - structured inorganic non - metallic compounds and / or plastic expandable microspheres.

6. The matching layer according to claim 5, wherein: The material of the first component includes the epoxy resin, the rubber, and the metal, and the material of the second component includes the epoxy resin, the metal oxide, and the hollow - structured inorganic non - metallic compound.

7. The matching layer according to claim 5, wherein: The epoxy resin includes at least one of bisphenol A epoxy resin and bisphenol F epoxy resin; The rubber includes at least one of thermoplastic SBS elastomer, nitrile rubber, butyl rubber, styrene - butadiene rubber, cis - 1,4 - polybutadiene rubber, ethylene - propylene - diene monomer rubber, silicone rubber, and fluororubber; The metal includes at least one of tungsten, copper, iron, and lead; The metal oxide includes at least one of tungsten trioxide, iron oxide, aluminum oxide, zinc oxide, and magnesium oxide; The inorganic non - metallic compound includes at least one of glass, ceramics, and boron carbide.

8. The matching layer according to claim 1, wherein the range of the first sound velocity or the second sound velocity is 1400 m / s to 3500 m / s.

9. An ultrasonic transducer, comprising: A piezoelectric layer and the matching layer according to any one of claims 1-8 above, wherein, The matching layer is disposed between the piezoelectric layer and the object to be measured, and the piezoelectric layer achieves acoustic matching with the object to be measured through the matching layer, and the piezoelectric layer is used to achieve the conversion between ultrasonic waves and electric energy.

10. The ultrasonic transducer according to claim 9, wherein: The thickness of the piezoelectric layer includes at least a first thickness and a second thickness, and the first thickness and the second thickness are not equal; The gradient distribution of the sound velocity of the matching layer corresponds to the thickness distribution of the piezoelectric layer.

11. The ultrasonic transducer according to claim 10, wherein: The gradient distribution of the sound velocity of the matching layer has an inverse relationship with the thickness distribution of the piezoelectric layer.

12. The ultrasonic transducer according to claim 10, wherein: The first sound velocity of the first component of the matching layer corresponds to the first thickness of the piezoelectric layer, and the second sound velocity of the second component of the matching layer corresponds to the second thickness of the piezoelectric layer; The first thickness is greater than the second thickness, and the first sound velocity is less than the second sound velocity.

13. A method for preparing the matching layer according to any one of claims 1-8, comprising: Configuring the first component and the second component according to the target acoustic impedance and the target sound velocity gradient distribution required to be achieved by the matching layer; Respectively disposing the first component and the second component at corresponding preset positions; Curing for a preset duration at a preset temperature to obtain the matching layer.

14. The method according to claim 13, wherein the step of respectively disposing the first component and the second component at corresponding preset positions includes: Disposing the first component and the second component at the corresponding preset positions by pouring, filling or injecting.

15. The method according to claim 13, wherein the preset temperature is set according to the types of substances, proportions and sizes configured in the first component and the second component.

16. According to the method of claim 13, the range of the preset temperature is 20°C to 100°C, and the range of the preset duration is 2h to 48h.

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