Ultrasonic transducer, ultrasonic transmitting and receiving system and time difference method flow measurement system

Abstract

The invention relates to the technical field of ultrasonic transducers, particularly provides an ultrasonic transducer, an ultrasonic transceiving system and a time difference method flow measurement system, and aims to solve the problem that optimal performance cannot be achieved in the same structure simultaneously due to the characteristic that directivity and omni-directivity of the ultrasonic transducer are mutually restricted. In order to achieve the purpose, the ultrasonic transducer comprises a transduction chip, a transmitting unit and a receiving unit, the transmitting unit and the receiving unit are arranged on the surface of the transduction chip, the transmitting unit comprises a plurality of first piezoelectric elements, and the receiving unit comprises a plurality of second piezoelectric elements; the plurality of first piezoelectric elements and the plurality of second piezoelectric elements are arranged in a two-dimensional array, and the number of the first piezoelectric elements is larger than that of the second piezoelectric elements. The ultrasonic transducer is divided into a transmitting part and a receiving part, so that the transducer can have good directivity and omnidirectivity at the same time, and the transmitting-receiving comprehensive performance under the two ultrasonic transducer working states of a self-transmitting and self-receiving mode and a mutual transmitting and receiving mode is optimized.

Description

Technical Field

[0001] The present application relates to the technical field of ultrasonic transducers, and in particular to an ultrasonic transducer, an ultrasonic transceiver system, and a time difference flow measurement system. Background Art

[0002] Ultrasonic transducers are widely used in non-destructive testing, industrial automation, target recognition, medical imaging, speed and distance detection, and other fields. Traditionally, ultrasonic transducers based on bulk piezoelectric ceramic materials are commonly used. However, such ultrasonic transducers have poor acoustic coupling performance (to water or air) and are expensive to process into the two-dimensional arrays required for three-dimensional imaging. Therefore, micromachined ultrasonic transducers (MUTs) based on the increasingly mature microelectromechanical systems (MEMS) technology have emerged. Based on different driving methods, micromachined ultrasonic transducers can be divided into capacitive micromachined ultrasonic transducers (CMUTs) and piezoelectric micromachined ultrasonic transducers (PMUTs).

[0003] Currently, piezoelectric micromachined ultrasonic transducers have been applied to many fields such as imaging and sensing. Existing piezoelectric micromachined ultrasonic transducers have the same structure when transmitting and receiving signals. A transmit / receive switch (T / R Switch) is required in the back-end circuit. During the signal transmission phase, the transmit / receive switch (T / R Switch) switches the piezoelectric micromachined ultrasonic transducer to the transmit channel, and during the signal reception phase, the switch switches the piezoelectric micromachined ultrasonic transducer to the receive channel, thereby achieving both signal transmission and reception functions. However, this signal transmission and reception process not only complicates the signal processing chain and increases the equipment deployment cost, but also, the directivity and omnidirectionality of the piezoelectric micromachined ultrasonic transducer are mutually restrictive characteristics, making it impossible to achieve optimal performance simultaneously in the same structure. That is, if the piezoelectric micromachined ultrasonic transducer has good transmit signal performance, then its corresponding receive signal performance is poor; and if the piezoelectric micromachined ultrasonic transducer has good receive signal performance, then its corresponding transmit signal performance is poor. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present application proposes an ultrasonic transducer, an ultrasonic transceiver system, and a time difference flow measurement system.

[0005] In a first aspect, an embodiment of the present application provides an ultrasonic transducer, comprising a transducer chip and a transmitting unit and a receiving unit arranged on the surface of the transducer chip, the transmitting unit comprising a plurality of first piezoelectric elements, and the receiving unit comprising a plurality of second piezoelectric elements; the plurality of first piezoelectric elements and the plurality of second piezoelectric elements are arranged into a two-dimensional array, and the number of the first piezoelectric elements is greater than the number of the second piezoelectric elements.

[0006] In some embodiments of the present application, the multiple first piezoelectric elements are arranged into an annular emitting area, and a planar receiving area is provided in the area enclosed by the inner ring of the annular emitting area, and the planar receiving area includes at least one second piezoelectric element.

[0007] In some embodiments of the present application, the transmitting unit includes multiple layers of transmitting areas, each layer of the transmitting area includes multiple first piezoelectric elements; the receiving unit includes multiple layers of receiving areas, each layer of the receiving area includes multiple second piezoelectric elements; at least one layer of the receiving area is arranged between any two layers of the transmitting areas.

[0008] In some embodiments of the present application, the multi-layer emitting area includes a plurality of annular emitting areas nested in sequence from the outside to the inside, an annular receiving area is provided between any two adjacent annular emitting areas, and a surface receiving area is provided in the area enclosed by the inner ring of the innermost annular emitting area, and the surface receiving area includes at least one of the second piezoelectric elements.

[0009] In some embodiments of the present application, the shape of the annular emitting area includes any one of a circular ring, an elliptical ring, a polygonal ring or an irregular ring; the shape of the surface receiving area includes any one of a circular, elliptical, polygonal or irregular shape; and the shape of the annular emitting area is adapted to the shape of the surface receiving area.

[0010] In some embodiments of the present application, the shape of the annular emitting area includes any one of a circular ring, an elliptical ring, a polygonal ring or an irregular ring; the shape of the annular receiving area includes any one of a circular ring, an elliptical ring, a polygonal ring or an irregular ring; and the shape of the annular emitting area is adapted to the shape of the annular receiving area.

[0011] In some embodiments of the present application, it is characterized in that the first piezoelectric element and the second piezoelectric element both include a top electrode layer, a piezoelectric layer, a bottom electrode layer, a passive layer and a substrate arranged in sequence; the substrate includes an etched cavity with a cavity.

[0012] In some embodiments of the present application, the shape of the two-dimensional array includes any one of a rectangle, a circle, an annulus, and a hexagon.

[0013] In a second aspect, an embodiment of the present application provides an ultrasonic transceiver system, comprising the ultrasonic transducer described in the first aspect above.

[0014] In a third aspect, an embodiment of the present application provides a time-difference flow measurement system, comprising the ultrasonic transducer described in the first aspect above.

[0015] The technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0016] The ultrasonic transducer of the embodiment of the present application includes a transducer chip and a transmitting unit and a receiving unit arranged on the surface of the transducer chip, the transmitting unit includes a plurality of first piezoelectric elements, and the receiving unit includes a plurality of second piezoelectric elements; the plurality of first piezoelectric elements and the plurality of second piezoelectric elements are arranged in a two-dimensional array, and the number of the first piezoelectric elements is greater than the number of the second piezoelectric elements. By splitting the ultrasonic transducer into two parts, namely, transmitting and receiving, the transducer can have both good directivity and omnidirectionality. The receiving unit and the transmitting unit are designed separately, which can reduce the acoustic crosstalk and electrical crosstalk of the ultrasonic transducer when transmitting signals, reduce noise, and improve the signal-to-noise ratio. Moreover, the independent design of the transmitting unit allows the use of high-voltage drive without affecting the receiving unit, which can significantly improve the energy efficiency. In addition, the number of first piezoelectric elements in the transmitting unit is large, which can form more precise beam control; the number of second piezoelectric elements in the receiving unit is small but reasonably distributed, supporting omnidirectional reception and signal fusion, thereby greatly improving the transmission-reception comprehensive performance of the ultrasonic transducer in both the self-transmitting and self-receiving mode and the mutual transmission and reception mode.

[0017] Additional aspects and advantages of the present application will be given in part in the description below and in part will become apparent from the description below or learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0019] Figure 1 A schematic structural diagram of an ultrasonic transducer in the prior art is shown;

[0020] Figure 2 A schematic structural diagram of an ultrasonic transducer provided in an embodiment of the present application is shown;

[0021] Figure 3 A schematic structural diagram of another ultrasonic transducer provided in an embodiment of the present application is shown;

[0022] Figure 4 A schematic structural diagram of another ultrasonic transducer provided in an embodiment of the present application is shown;

[0023] Figure 5 A schematic structural diagram of another ultrasonic transducer provided in an embodiment of the present application is shown;

[0024] Figure 6 A schematic diagram showing the structure of an ultrasonic transducer provided in an embodiment of the present application in which both the annular transmitting area and the receiving area are polygonal rings is shown;

[0025] Figure 7 A schematic structural diagram of a piezoelectric element provided in an embodiment of the present application is shown;

[0026] Figure 8 A schematic structural diagram of an actual testing system for an ultrasonic transducer provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0027] The following describes exemplary embodiments of the present application in more detail with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0028] Ultrasonic transducers are widely used in non-destructive testing, industrial automation, target recognition, medical imaging, speed and distance detection, and other fields. Traditionally, ultrasonic transducers based on bulk piezoelectric ceramic materials are commonly used. However, such ultrasonic transducers have poor acoustic coupling performance (to water or air) and are expensive to process into the two-dimensional arrays required for three-dimensional imaging. Therefore, micromachined ultrasonic transducers (MUTs) based on the increasingly mature microelectromechanical systems (MEMS) technology have emerged. Based on different driving methods, micromachined ultrasonic transducers can be divided into capacitive micromachined ultrasonic transducers (CMUTs) and piezoelectric micromachined ultrasonic transducers (PMUTs).

[0029] Currently, piezoelectric micromachined ultrasonic transducers have been used in many fields such as imaging and sensing. Figure 1As shown, the existing piezoelectric micromachined ultrasonic transducer has the same structure when transmitting and receiving signals, and a transmit / receive switch (T / R Switch) needs to be connected to the circuit. In the signal transmission stage, the switch state of the piezoelectric micromachined ultrasonic transducer is switched to the transmit channel through the transmit / receive switch (T / R Switch), and in the signal reception stage, the switch state of the piezoelectric micromachined ultrasonic transducer is switched to the receive channel, thereby realizing the signal transmission function and the signal reception function. However, this process of signal transmission and reception not only makes the signal processing link complex and the equipment deployment cost high, but also the directivity and omnidirectionality of the piezoelectric micromachined ultrasonic transducer are two mutually restrictive characteristics, and it is impossible to achieve optimal performance at the same time in the same structure. That is to say, if the performance of the transmission signal of the piezoelectric micromachined ultrasonic transducer is good, then the corresponding performance of its reception signal is not good; if the performance of the reception signal of the piezoelectric micromachined ultrasonic transducer is good, then the corresponding performance of its transmission signal is not good.

[0030] Based on this, an embodiment of the present application provides an ultrasonic transducer. The solution of the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0031] See also Figure 2 A schematic structural diagram of an ultrasonic transducer is shown, which specifically includes a transducer chip and a transmitting unit and a receiving unit arranged on the surface of the transducer chip, the transmitting unit includes multiple first piezoelectric elements, and the receiving unit includes multiple second piezoelectric elements. The multiple first piezoelectric elements and the multiple second piezoelectric elements are arranged in a two-dimensional array, and the number of first piezoelectric elements is greater than the number of second piezoelectric elements.

[0032] The ultrasonic transducer in the embodiment of the present application may specifically refer to a piezoelectric micromachined ultrasonic transducer (PMUT).

[0033] The transducer chip is the core component of the ultrasonic transducer, responsible for converting electrical to acoustic signals. Its role is similar to that of the CPU in a computer. The transducer chip operates in two modes: transmitting and receiving. When the ultrasonic transducer is in the transmitting mode, it acts as a transmitter, emitting ultrasonic signals using the transmitter unit on the transducer chip. When the ultrasonic transducer is in the receiving mode, it acts as a receiver, receiving the ultrasonic signals using the receiver unit on the transducer chip and converting them into electrical signals.

[0034] The first piezoelectric element and the second piezoelectric element are both core functional units in the ultrasonic transducer chip, and refer to functional material structures that realize the mutual conversion of electrical energy and mechanical energy (acoustic energy) through the piezoelectric effect. The piezoelectric effect is common knowledge known to those skilled in the art, and will not be repeated in the embodiments of this application. It should be noted that this application Figure 2The diagram shows only one structural diagram of the ultrasonic transducer. In actual design, the transmitting unit and the receiving unit in the ultrasonic transducer can adjust the specific position of the transmitting unit or the receiving unit in the two-dimensional array according to actual needs. Figure 2 The ultrasonic transducer shown should not be understood as limiting to all specific structures of the present application.

[0035] The embodiment of the present application splits the ultrasonic transducer into two parts, namely, a transmitting part and a receiving part, so that the transducer can have good directivity and omnidirectionality at the same time. The receiving unit and the transmitting unit are designed separately, which can reduce the acoustic crosstalk and electrical crosstalk of the ultrasonic transducer when transmitting signals, reduce noise, and improve the signal-to-noise ratio; furthermore, the independent design of the transmitting unit allows the ultrasonic transducer to use high-voltage drive, but does not affect the receiving unit, which can significantly improve the energy efficiency ratio; in addition, the first piezoelectric elements of the transmitting unit are large in number, which can form more precise beam control, and the second piezoelectric elements of the receiving unit are small in number but reasonably distributed, supporting omnidirectional reception and signal fusion, thereby greatly improving the transmitting-receiving comprehensive performance of the ultrasonic transducer in both the self-transmitting and receiving mode and the mutual transmitting and receiving mode.

[0036] Based on the above embodiment, in some modified implementations, the shape of the two-dimensional array may include any one of a rectangle, a circle, a ring, and a hexagon.

[0037] Two-dimensional arrays are designed in different shapes, which can provide different ultrasonic transducers for different application scenarios, better meet the needs of specific applications, and improve the adaptability of ultrasonic transducers. Moreover, two-dimensional arrays of different shapes have different directivity and omnidirectionality in sound wave transmission and reception. For example, circular and annular arrays can usually provide more uniform sound field distribution, while hexagonal arrays can achieve higher space utilization and flexibility in some cases. Through this design flexibility, ultrasonic transducers can perform more precise sound field control as needed, improving imaging quality and signal reception. Furthermore, in some applications, the combination of ultrasonic transducers with different array shapes will also produce complementary effects. For example, rectangular arrays are suitable for larger detection areas, while circular arrays are suitable for local detection requiring high precision. Such flexibility can provide more options for actual application scenarios, thereby achieving optimal performance. Based on the above embodiments, in some modified implementations, multiple first piezoelectric elements are arranged into an annular emitting area, and a planar receiving area is provided in the area surrounded by the inner ring of the annular emitting area. The planar receiving area includes at least one second piezoelectric element, specifically Figure 3 shown.

[0038] The annular emitting area can effectively focus sound waves, thereby achieving better sound wave directionality, enabling it to emit stronger sound energy in a specific direction, and improving the imaging or detection effect; moreover, the annular emitting area allows sound waves to be emitted in certain directions while suppressing interference signals in other directions, reducing the impact of background noise on the received signal, and improving the signal-to-noise ratio and imaging quality of the signal; furthermore, the annular emitting area can adapt to working under sound waves of different frequencies, and can significantly enhance the working performance of the ultrasonic transducer at different frequencies.

[0039] Furthermore, a planar receiving area is provided in the area enclosed by the inner ring of the shaped emitting area, so that multiple second piezoelectric elements can be concentrated on one plane to form a larger receiving area, which can effectively improve the ultrasonic transducer's ability to capture reflected signals, thereby improving the overall sensitivity of the ultrasonic transducer.

[0040] Based on the above embodiment, in some modified implementations, the transmitting unit includes multiple layers of transmitting areas, each layer of transmitting areas includes multiple first piezoelectric elements, the receiving unit includes multiple layers of receiving areas, each layer of receiving areas includes multiple second piezoelectric elements, and at least one layer of receiving areas is provided between any two layers of transmitting areas. Figure 4 (a) and 4(b).

[0041] It should be noted that this application Figure 4 (a) and 4 (b) show only partial structural diagrams of the ultrasonic transducer. In actual design, the transmitting unit and the receiving unit in the ultrasonic transducer can be set in specific positions according to the actual shape of the two-dimensional array. Figure 4 The ultrasonic transducers shown in (a) and 4 (b) should not be understood as limiting all specific structures of the present application.

[0042] The structure of the multi-layer transmitting area and the receiving area enables the ultrasonic transducer to transmit and receive sound waves at different depths or heights, thereby improving the spatial resolution of the imaging and enabling the system using the ultrasonic transducer to obtain more detailed information, thereby achieving better imaging effects in the imaging of more complex structures. Furthermore, the multi-layer receiving area can receive signals at different angles and depths, thereby enhancing the ability to receive weak signals and significantly improving the sensitivity of ultrasonic detection, especially when detecting deep tissue or material defects. Furthermore, by providing a receiving layer between the transmitting area and the transmitting area, direct interference signals can be effectively reduced, the signal-to-noise ratio of the target signal can be improved, and background noise can be better filtered, thereby enhancing the recognition ability of the ultrasonic transducer. The design of the multi-layer transmitting area can optimize the energy distribution of the sound wave, avoid the energy loss caused by the sound wave concentrating in a specific area, help to achieve a more uniform sound field, and improve the imaging quality. Furthermore, the design of the multi-layer transmitting area and the receiving area enables the layers to be effectively isolated, reduces the mutual interference between different layers, and helps to improve the stability and reliability of imaging.

[0043] On the basis of the above embodiment, in some modified implementations, the multi-layer emission area includes a plurality of annular emission areas nested in sequence from the outside to the inside, an annular receiving area is provided between any two adjacent annular emission areas, and a planar receiving area is provided in the area surrounded by the inner ring of the innermost annular emission area, and the planar receiving area includes at least one second piezoelectric element, which can be specifically as follows: Figure 5 shown.

[0044] Through the nested design of the annular emitting areas, the emission and receiving parameters can be flexibly adjusted within different radii, which can adapt to different application requirements and significantly improve the adaptability of the ultrasonic transducer. Moreover, multiple annular emitting areas can effectively optimize the emission angle and energy distribution of sound waves, making the propagation of sound waves in space more uniform, which helps to improve the quality and clarity of imaging; furthermore, the multi-layer annular receiving areas can effectively capture signals from different directions, increasing the ability to receive weak signals; furthermore, the annular receiving areas set between adjacent annular emitting areas can effectively isolate the interference between different emitting areas, reduce mutual interference between signals, and thus improve the stability and accuracy of imaging; furthermore, the embedded planar receiving area concentrates multiple second piezoelectric elements, which can provide higher resolution and improve imaging quality.

[0045] Based on the above embodiments, in some modified implementations, the shape of the annular emitting area may include any one of a circular ring, an elliptical ring, a polygonal ring or an irregular ring, and the shape of the surface receiving area may include any one of a circular, elliptical, polygonal or irregular shape, and the shape of the annular emitting area is adapted to the shape of the surface receiving area.

[0046] It should be noted that the shape of the annular emitting area is adapted to the shape of the planar receiving area, which means that the shape of the annular emitting area is similar to the shape of the planar receiving area. For example, if the shape of the annular emitting area is a circular ring, then the corresponding shape of the planar receiving area is a circle; if the shape of the annular emitting area is a hexagonal ring, then the corresponding shape of the planar receiving area is a hexagon.

[0047] The adaptation of the shape of the annular transmitting area to the shape of the planar receiving area can ensure the optimal sound wave propagation path between transmission and reception, reduce signal attenuation and distortion, and effectively reduce electromagnetic interference or acoustic interference from the environment, improve signal accuracy and stability, and thus enhance the performance of the ultrasonic transducer.

[0048] Based on the above embodiments, in some modified implementations, the shape of the annular emitting area may include any one of a circular ring, an elliptical ring, a polygonal ring or an irregular ring, and the shape of the annular receiving area may include any one of a circular ring, an elliptical ring, a polygonal ring or an irregular ring, and the shape of the annular emitting area is adapted to the shape of the annular receiving area.

[0049] Similarly, the shape of the annular emitting area is adapted to the shape of the annular receiving area, which means that the shape of the annular emitting area is similar to the shape of the annular receiving area. For example, if the shape of the annular emitting area is a circular ring, then the shape of the corresponding annular receiving area is a circular ring; if the shape of the annular emitting area is a polygonal ring, then the shape of the corresponding annular receiving area is a polygonal ring. For example, see Figure 6 In the ultrasonic transducer shown, the shape of the annular transmitting area is a polygonal ring, and the corresponding annular receiving area is also a polygonal ring with a similar shape.

[0050] See also Figure 7 As shown, based on the above embodiments, in some modified implementations, the first piezoelectric element and the second piezoelectric element both include a top electrode layer, a piezoelectric layer, a bottom electrode layer, a passive layer and a substrate arranged in sequence, and the substrate includes an etched cavity with a cavity.

[0051] In an embodiment of the present application, the top electrode layer can be composed of a thin film of a conductive material such as Au (gold), Pt (platinum), Mo (molybdenum), Al (aluminum), ITO (indium tin oxide); the piezoelectric layer can be composed of a thin film of a piezoelectric material such as PZT (lead titanium zirconate titanate), AlN (aluminum nitride), ScAlN (scandium aluminum nitride), ZnO (zinc oxide), KNN (potassium sodium lead niobate); the substrate can be composed of a thin film such as Si (silicon), Glass (glass), PI (polyimide), etc.

[0052] The ultrasonic transducer of the embodiment of the present application is designed to have both good directivity and omnidirectionality by splitting the ultrasonic transducer into two parts: transmitting and receiving. The receiving unit and the transmitting unit are designed separately, which can reduce the acoustic and electrical crosstalk when the ultrasonic transducer transmits signals, reduce noise, and improve the signal-to-noise ratio. Moreover, the independent design of the transmitting unit allows the use of high-voltage drive without affecting the receiving unit, which can significantly improve the energy efficiency. In addition, the large number of first piezoelectric elements in the transmitting unit can form more precise beam control, for example, see Figure 8 In the ultrasonic ranging application scenario in which the ultrasonic transducer is self-emitting and self-receiving, when the ultrasonic transducer of the present application transmits a signal, since the receiving unit is not working, that is, the receiving unit does not exist, then the directional range of the signal transmitted by the transmitting unit is relatively small, thereby improving the directionality of the sound beam of the transmitting transducer, so that the detection result contains more position information and the identification is more accurate. At the same time, the emission sound intensity of the transmitting unit will also be stronger, so that the ultrasonic wave can propagate in the medium for a longer time / distance, increasing the detection range; and when the ultrasonic receiving unit receives the signal, since the transmitting unit is not working, that is, the transmitting unit does not exist, then the range area of the signal received by the receiving unit is relatively large, thereby improving the omnidirectionality of the sound beam of the receiving transducer, making the detection of the ultrasonic transducer more sensitive.

[0053] In addition, when using the ultrasonic transducer in the embodiment of the present application, there is no need to use a transmit / receive switch (T / RSwitch), which not only reduces the complexity of detection, but also reduces the volume of the ultrasonic transducer, thereby significantly reducing the manufacturing cost of the ultrasonic transducer.

[0054] An embodiment of the present application further provides an ultrasonic transceiver system, which includes the ultrasonic transducer described in the above embodiment.

[0055] The ultrasonic transceiver system provided in the embodiment of the present application and the ultrasonic transducer provided in the above embodiment are based on the same inventive concept and have the same beneficial effects as the methods adopted, operated or implemented therein.

[0056] An embodiment of the present application further provides a time-difference flow measurement system, which includes the ultrasonic transducer described in the above embodiment.

[0057] The time-difference flow measurement system provided in the embodiment of the present application and the ultrasonic transducer provided in the above embodiment are based on the same inventive concept and have the same beneficial effects as the methods adopted, operated or implemented therein.

[0058] It should be noted that:

[0059] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0060] Similarly, it should be understood that in order to streamline the present application and aid in understanding one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present application, various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the claims below, inventive aspects lie in fewer than all the features of the individual embodiments disclosed above. Accordingly, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim itself serving as a separate embodiment of the present application.

[0061] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and in addition may be divided into multiple submodules or subunits or subcomponents. All features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed herein may be combined in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0062] Furthermore, those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of this application and to form different embodiments. For example, in the claims below, any of the claimed embodiments may be used in any combination.

[0063] The various component embodiments of the present application can be implemented in hardware, or implemented in a software module running on one or more processors, or implemented in a combination thereof. Those skilled in the art will appreciate that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functions of some or all of the components in the creation device of the virtual machine according to an embodiment of the present application. The application can also be implemented as a part or all of the equipment or device program (for example, computer program and computer program product) for performing the method described herein. Such a program realizing the present application can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0064] It should be noted that the above embodiments illustrate rather than limit the present application, and that a person skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbols placed between brackets should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present application may be implemented by means of hardware comprising several different elements and by means of appropriately programmed computers. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

[0065] The above description is merely a preferred embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An ultrasonic transducer, characterized in that: It includes a transducer chip and a transmitting unit and a receiving unit arranged on the surface of the transducer chip, wherein the transmitting unit includes a plurality of first piezoelectric elements and the receiving unit includes a plurality of second piezoelectric elements; The plurality of first piezoelectric elements and the plurality of second piezoelectric elements are arranged in a two-dimensional array, and the number of the first piezoelectric elements is greater than the number of the second piezoelectric elements.

2. The ultrasonic transducer according to claim 1, characterized in that The plurality of first piezoelectric elements are arranged into an annular emitting area, a planar receiving area is provided within an area enclosed by an inner ring of the annular emitting area, and the planar receiving area includes at least one second piezoelectric element.

3. The ultrasonic transducer according to claim 1, characterized in that The transmitting unit includes multiple layers of transmitting areas, each layer of the transmitting areas includes multiple first piezoelectric elements; the receiving unit includes multiple layers of receiving areas, each layer of the receiving areas includes multiple second piezoelectric elements; At least one layer of the receiving area is arranged between any two layers of the transmitting areas.

4. The ultrasonic transducer according to claim 3, characterized in that The multi-layer emitting area includes a plurality of annular emitting areas nested in sequence from the outside to the inside, and an annular receiving area is arranged between any two adjacent annular emitting areas. A surface receiving area is arranged in the area surrounded by the inner ring of the innermost annular emitting area, and the surface receiving area includes at least one of the second piezoelectric elements.

5. The ultrasonic transducer according to claim 2 or 4, characterized in that: The shape of the annular emitting area includes any one of a circular ring, an elliptical ring, a polygonal ring or an irregular ring; the shape of the surface receiving area includes any one of a circular, elliptical, polygonal or irregular shape; and the shape of the annular emitting area is adapted to the shape of the surface receiving area.

6. The ultrasonic transducer according to claim 4, characterized in that The shape of the annular emitting area includes any one of a circular ring, an elliptical ring, a polygonal ring or an irregular ring; the shape of the annular receiving area includes any one of a circular ring, an elliptical ring, a polygonal ring or an irregular ring; and the shape of the annular emitting area is adapted to the shape of the annular receiving area.

7. The ultrasonic transducer according to any one of claims 1 to 4, characterized in that: The first piezoelectric element and the second piezoelectric element each include a top electrode layer, a piezoelectric layer, a bottom electrode layer, a passive layer and a substrate arranged in sequence; The substrate includes an etch chamber with a cavity.

8. The ultrasonic transducer according to any one of claims 1 to 4, characterized in that: The shape of the two-dimensional array includes any one of a rectangle, a circle, an annulus, and a hexagon.

9. An ultrasonic transceiver system, characterized in that: The ultrasonic transducer comprises the ultrasonic transducer according to any one of claims 1 to 8.

10. A time difference flow measurement system, characterized in that: The ultrasonic transducer comprises the ultrasonic transducer according to any one of claims 1 to 8.

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