Piezoelectric micromechanical ultrasonic transducer and method, device, equipment and medium for regulating same

Abstract

This application relates to the field of ultrasonic transducer technology, specifically providing a piezoelectric micromechanical ultrasonic transducer and its adjustment method, device, equipment, and medium. The aim is to solve the problem of a sharp decrease in signal amplitude due to a deviation between the actual operating frequency and the design frequency of the ultrasonic transducer, affecting its use. To this end, the method of this application includes: obtaining the target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer and the actual resonant frequency when a DC voltage bias is applied; determining whether a preset matching condition is met; if met, completing the performance adjustment of the piezoelectric micromechanical ultrasonic transducer; otherwise, dynamically adjusting the DC voltage bias and the thickness of the top electrode of the piezoelectric micromechanical ultrasonic transducer, obtaining the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer as the actual resonant frequency, and continuing to execute the step of determining whether the preset matching condition is met. This effectively improves the working performance of the piezoelectric micromechanical ultrasonic transducer and reduces frequency deviation.

Description

Technical Field

[0001] This application relates to the field of ultrasonic transducer technology, specifically to a piezoelectric micromechanical ultrasonic transducer and its adjustment method, device, equipment, and medium. Background Technology

[0002] Ultrasonic transducers have wide applications in non-destructive testing, distance detection, medical imaging, and flow velocity detection. Traditional volume pressure ultrasonic transducers, generally based on piezoelectric ceramic materials, operate in thickness mode; however, these transducers suffer from poor acoustic coupling performance and high manufacturing costs. Micromechanical ultrasonic transducers (MUTs), based on microelectromechanical systems (MEMS) technology, operate in bending mode, offering better acoustic coupling performance and lower manufacturing costs compared to traditional piezoelectric transducers, making them a leading trend in advanced ultrasonic transducers. Furthermore, MUTs offer numerous advantages such as small size, low power consumption, large bandwidth, ease of arraying, and easy integration with electronic systems, demonstrating broad application prospects.

[0003] However, frequency mismatch is one of the key issues limiting the performance of piezoelectric micromechanical ultrasonic transducers. Due to uncertainties such as manufacturing process errors, the actual operating frequency of a piezoelectric micromechanical ultrasonic transducer will deviate from the design frequency within a certain range. For applications such as time-of-flight flow meters, where ultrasonic transducers need to be used in pairs as transmitters and receivers, the deviation in their operating frequencies can lead to problems such as a sharp decrease in signal amplitude. Summary of the Invention

[0004] To address the above problems, this application provides a method for adjusting a piezoelectric micromechanical ultrasonic transducer. The piezoelectric micromechanical ultrasonic transducer includes a top electrode. By acquiring the target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer, and the actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer, the method determines whether the matching degree between the actual resonant frequency and the target resonant frequency meets a preset matching condition. If not, the method dynamically adjusts the DC voltage bias and the thickness of the top electrode, acquires the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer as the actual resonant frequency, and continues to determine whether the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching condition. This process continues until the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching condition, thus completing the performance adjustment of the piezoelectric micromechanical ultrasonic transducer. This method enables the deviation between the actual resonant frequency and the target resonant frequency under ideal conditions to reach an ideal state, thereby significantly improving the working performance of the piezoelectric micromechanical ultrasonic transducer.

[0005] In a first aspect, embodiments of this application provide a method for adjusting a piezoelectric micromechanical ultrasonic transducer, wherein the piezoelectric micromechanical ultrasonic transducer includes a top electrode, comprising: acquiring a target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer; acquiring an actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer; determining whether the matching degree between the actual resonant frequency and the target resonant frequency meets a preset matching condition; if it does, then completing the performance adjustment of the piezoelectric micromechanical ultrasonic transducer; otherwise, dynamically adjusting the DC voltage bias and the thickness of the top electrode, acquiring the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer as the actual resonant frequency, and continuing to execute the step of determining whether the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching condition.

[0006] Secondly, embodiments of this application provide a piezoelectric micromechanical ultrasonic transducer adjustment device. The piezoelectric micromechanical ultrasonic transducer includes a top electrode and comprises: a first acquisition module for acquiring a target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer; a second acquisition module for acquiring an actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer; a judgment module for judging whether the matching degree between the actual resonant frequency and the target resonant frequency meets a preset matching condition; and an adjustment module for performing performance adjustment of the piezoelectric micromechanical ultrasonic transducer if the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching condition; otherwise, dynamically adjusting the DC voltage bias and the thickness of the top electrode, acquiring the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer as the actual resonant frequency, and continuing to execute the operation of the judgment module.

[0007] Thirdly, embodiments of this application provide a piezoelectric micromechanical ultrasonic transducer, including the piezoelectric micromechanical ultrasonic transducer adjustment device provided in the second aspect above, and further including: a piezoelectric layer, wherein the thickness of the piezoelectric layer is less than or equal to 2 micrometers.

[0008] Fourthly, embodiments of this application provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the method described in the first aspect above.

[0009] Fifthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in the first aspect above.

[0010] The technical solutions provided in this application embodiment have at least the following technical effects or advantages:

[0011] This embodiment of the piezoelectric micromechanical ultrasonic transducer includes a top electrode. By acquiring the target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer and the actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer, it is determined whether the matching degree between the actual resonant frequency and the target resonant frequency meets a preset matching condition. If not, the DC voltage bias and the thickness of the top electrode are dynamically adjusted. The current resonant frequency of the piezoelectric micromechanical ultrasonic transducer is acquired as the actual resonant frequency, and the matching degree between the actual resonant frequency and the target resonant frequency is further determined until the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching condition. This completes the performance adjustment of the piezoelectric micromechanical ultrasonic transducer, enabling the deviation between the actual resonant frequency and the target resonant frequency under ideal conditions to reach an ideal state, thereby significantly improving the working performance of the piezoelectric micromechanical ultrasonic transducer.

[0012] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0013] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0014] Figure 1 A schematic diagram of the structure of the piezoelectric micromechanical ultrasonic transducer without applied DC voltage bias provided in the embodiment of this application is shown;

[0015] Figure 2 A schematic diagram of the structure of the piezoelectric micromechanical ultrasonic transducer with applied DC voltage bias provided in the embodiment of this application is shown;

[0016] Figure 3 A flowchart of a piezoelectric micromechanical ultrasonic transducer adjustment method provided in an embodiment of this application is shown;

[0017] Figure 4 This paper shows the variation of the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer provided in the embodiment of this application with the applied DC voltage bias when it is at the first operating frequency;

[0018] Figure 5 This paper shows the variation of the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer provided in the embodiment of this application with the applied DC voltage bias when it is at the second operating frequency;

[0019] Figure 6 The figure shows the impedance amplitude curve of the piezoelectric micromechanical ultrasonic transducer provided in the embodiment of this application, as detected by an impedance analyzer.

[0020] Figure 7 This illustration shows a schematic diagram of frequency domain observation of a piezoelectric micromechanical ultrasonic transducer under DC voltage bias using a laser Doppler vibrometer, as provided in an embodiment of this application.

[0021] Figure 8 This illustration shows a schematic diagram of time-domain observation of a piezoelectric micromechanical ultrasonic transducer under DC voltage bias using a laser Doppler vibrometer, as provided in an embodiment of this application.

[0022] Figure 9 The diagram shows a schematic of the actual resonant frequency variation of the piezoelectric micromechanical ultrasonic transducer obtained by adjusting the thickness of the top electrode according to an embodiment of this application.

[0023] Figure 10 This paper shows a schematic diagram of the structure of a piezoelectric micromechanical ultrasonic transducer adjustment device provided in an embodiment of this application;

[0024] Figure 11 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown. Detailed Implementation

[0025] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0026] Ultrasonic transducers have wide applications in non-destructive testing, distance detection, medical imaging, and flow velocity detection. Traditional volume pressure ultrasonic transducers, generally based on piezoelectric ceramic materials, operate in thickness mode; however, these transducers suffer from poor acoustic coupling performance and high manufacturing costs. Micromechanical ultrasonic transducers (MUTs), based on microelectromechanical systems (MEMS) technology, operate in bending mode, offering better acoustic coupling performance and lower manufacturing costs compared to traditional piezoelectric transducers, making them a leading trend in advanced ultrasonic transducers. Furthermore, MUTs offer numerous advantages such as small size, low power consumption, large bandwidth, ease of arraying, and easy integration with electronic systems, demonstrating broad application prospects.

[0027] See Figure 1As shown, the structure of a piezoelectric micromechanical ultrasonic transducer consists of, from top to bottom, a top electrode layer, a piezoelectric layer, a bottom electrode layer, and a support layer, typically with a cavity at the bottom. The top electrode layer can be composed of thin films of conductive materials such as Au (gold), Pt (platinum), Mo (molybdenum), Al (aluminum), and ITO (indium tin oxide). The piezoelectric layer can be composed of thin films of piezoelectric materials such as PZT (titanium lead zirconate titanate), AlN (aluminum nitride), ScAlN (scandium aluminum nitride), ZnO (zinc oxide), and KNN (lead potassium sodium niobate). The support layer can be composed of thin films of materials such as Si (silicon), Glass, and PI (polyimide). PZT and AlN are the two most commonly used piezoelectric materials in piezoelectric micromechanical ultrasonic transducers. AlN does not contain lead and its processing does not require high temperatures, making it frequently used in receiving devices. Conversely, PZT has a superior piezoelectric coefficient and is therefore often used in transmitting devices. Each individual piezoelectric micromechanical ultrasonic transducer can achieve both receiving and transmitting functions.

[0028] When the piezoelectric micromechanical ultrasonic transducer works as a transmitter, an electrical signal is applied between the top and bottom electrodes. Due to the inverse piezoelectric effect, the external electric field between the top and bottom electrodes can generate transverse stress in the piezoelectric material film, which in turn causes the film at the top of the chamber to bend, generating sound pressure and propagating to the surrounding environment. When receiving, the external acoustic signal causes the transducer to deform. Under the piezoelectric effect, the deformation of the piezoelectric micromechanical ultrasonic transducer is converted into a corresponding electrical signal and output to the external circuit.

[0029] However, frequency mismatch is one of the key issues limiting the performance of piezoelectric micromechanical ultrasonic transducers. Due to uncertainties such as manufacturing process errors, the actual operating frequency of a piezoelectric micromechanical ultrasonic transducer will deviate from the design frequency within a certain range. For applications such as time-of-flight flow meters, where ultrasonic transducers need to be used in pairs as transmitters and receivers, the deviation in their operating frequencies can lead to problems such as a sharp decrease in signal amplitude.

[0030] Based on this, see Figure 2 As shown, a DC voltage bias can be applied to the piezoelectric micromechanical ultrasonic transducer. By controllably adjusting the internal stress of the piezoelectric layer of the piezoelectric micromechanical ultrasonic transducer and optimizing the thickness of the top electrode of the piezoelectric micromechanical ultrasonic transducer, the actual resonant frequency generated can be changed, thereby reducing the deviation between the actual resonant frequency and the target resonant frequency under ideal conditions, and thus improving the working performance of the piezoelectric micromechanical ultrasonic transducer.

[0031] Furthermore, the piezoelectric layer of the piezoelectric micromechanical ultrasonic transducer can be manufactured using high-quality manufacturing processes, so that the thickness of the piezoelectric layer of the piezoelectric micromechanical ultrasonic transducer is less than or equal to 2 micrometers. This enables the piezoelectric micromechanical ultrasonic transducer to achieve a wide range of resonant frequency modulation, thereby realizing flexible switching between a relatively low frequency operating mode and a relatively high frequency mode.

[0032] Specifically, this application provides a method for adjusting a piezoelectric micromechanical ultrasonic transducer. The following description, in conjunction with the accompanying drawings, details the solution of this application embodiment.

[0033] See Figure 3 The flowchart shown illustrates a method for adjusting a piezoelectric micromechanical ultrasonic transducer, which specifically includes the following steps:

[0034] Step 101: Obtain the target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer.

[0035] In this embodiment, the target resonant frequency refers to the ideal resonant frequency generated by the piezoelectric micromechanical ultrasonic transducer when no DC voltage bias is applied to it.

[0036] In one embodiment, the mass density, bending stiffness, and shape of a piezoelectric micromechanical ultrasonic transducer can be obtained. Then, based on the shape of the piezoelectric micromechanical ultrasonic transducer, the length attribute of the transducer can be obtained. Finally, based on the mass density, bending stiffness, and length attribute, the target resonant frequency can be obtained.

[0037] It should be noted that the piezoelectric micromechanical ultrasonic transducer can be circular, rectangular, or elliptical in shape, etc. This application does not impose specific limitations on its embodiments.

[0038] In one embodiment, when the piezoelectric micromechanical ultrasonic transducer is circular, the radius of the circle can be obtained as the length attribute of the piezoelectric micromechanical ultrasonic transducer. Then, based on the mass density, bending stiffness, and radius, the target resonant frequency is obtained using the following formula 1, wherein formula 1 may include:

[0039]

[0040] in, Indicates the target resonant frequency. Indicates radius, Indicates bending stiffness. This indicates mass density.

[0041] In another embodiment, when the piezoelectric micromechanical ultrasonic transducer is rectangular, the length and width of the rectangle can be obtained as the length attribute of the piezoelectric micromechanical ultrasonic transducer. Then, based on the mass density, bending stiffness, and the length and width of the piezoelectric micromechanical ultrasonic transducer, the target resonant frequency can be obtained using the following formula 2:

[0042]

[0043] in, Indicates the target resonant frequency. Indicates length, Indicates width. Indicates bending stiffness. This indicates mass density.

[0044] Step 102: Obtain the actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer.

[0045] In one embodiment, the internal stress generated by the piezoelectric micromechanical ultrasonic transducer can be obtained, and then the actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer can be obtained based on the mass density, length properties and internal stress of the piezoelectric micromechanical ultrasonic transducer.

[0046] In some modified embodiments, the internal stress generated by the piezoelectric micromechanical ultrasonic transducer can be obtained by specifically obtaining the piezoelectric coefficient of the thin film in the top electrode, the elastic compliance coefficient and thickness of the piezoelectric material in the piezoelectric layer, wherein the elastic compliance coefficient includes a first elastic compliance coefficient in the x-direction and a second elastic compliance coefficient in the y-direction per unit area. Then, based on the piezoelectric coefficient, the first elastic compliance coefficient, the second elastic compliance coefficient, the thickness and the DC voltage bias, the in-plane stress per unit area of ​​the piezoelectric micromechanical ultrasonic transducer is calculated using the following formula 3. Finally, the average value of each in-plane stress is taken as the internal stress generated by the piezoelectric micromechanical ultrasonic transducer. Formula 3 may include:

[0047]

[0048] in, Indicates in-plane stress. Indicates the piezoelectric coefficient. This represents the first elasticity compliance coefficient. This represents the second flexibility coefficient, and V represents the DC voltage bias. Indicates thickness.

[0049] As can be seen from the embodiment in step 101 above, the shape of the piezoelectric micromechanical ultrasonic transducer can be circular, rectangular, or elliptical. Therefore, when the piezoelectric micromechanical ultrasonic transducer is circular, the actual resonant frequency when a DC voltage bias is applied to the transducer can be obtained based on its mass density, length attribute, and internal stress. Specifically, the radius of the transducer can be obtained and used as its length attribute. Then, based on the mass density, internal stress, and radius, the actual resonant frequency can be calculated using the following formula 4, where formula 4 includes:

[0050]

[0051] in, Indicates the actual resonant frequency. Indicates mass density, Indicates internal stress. Indicates the radius.

[0052] It should be noted that if the piezoelectric micromechanical ultrasonic transducer is rectangular, the length and width of the rectangle can be used as the length attribute of the piezoelectric micromechanical ultrasonic transducer; if the piezoelectric micromechanical ultrasonic transducer is elliptical, the major axis and minor axis of the ellipse can be used as the length attribute of the piezoelectric micromechanical ultrasonic transducer. Based on the principle that the actual resonant frequency is proportional to the square root of the internal stress, the actual resonant frequency can be calculated based on the mass density, internal stress, and length attribute.

[0053] Step 103: Determine whether the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching conditions. If not, proceed to step 104; otherwise, proceed to step 105.

[0054] In one embodiment, if the difference between the actual resonant frequency and the target resonant frequency is less than or equal to a preset threshold, it is determined that the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching condition; otherwise, it is determined that the matching degree between the actual resonant frequency and the target resonant frequency does not meet the preset matching condition.

[0055] It should be noted that the preset threshold refers to the threshold used to determine whether the actual resonant frequency matches the target resonant frequency. The preset threshold can be a threshold obtained by those skilled in the art based on experiments, or it can be a threshold obtained by those skilled in the art by adjusting a set threshold according to actual needs. This application does not specifically limit this.

[0056] Based on the above implementation, in some modified implementations, the actual anti-resonance frequency of the piezoelectric micromechanical ultrasonic transducer can also be obtained. Based on the actual resonant frequency and the actual anti-resonance frequency, the electromechanical coupling coefficient of the piezoelectric micromechanical ultrasonic transducer is calculated. If the electromechanical coupling coefficient is greater than or equal to a preset coefficient threshold, it is determined that the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching condition; otherwise, it is determined that the matching degree between the actual resonant frequency and the target resonant frequency does not meet the preset matching condition.

[0057] Furthermore, based on the actual resonant frequency and the actual anti-resonant frequency, the electromechanical coupling coefficient of the piezoelectric micromechanical ultrasonic transducer is calculated. Specifically, the electromechanical coupling coefficient can be calculated using the following formula 5 based on the actual resonant frequency and the actual anti-resonant frequency:

[0058]

[0059] in, Represents the electromechanical coupling coefficient. Indicates the actual anti-resonant frequency. This represents the actual resonant frequency.

[0060] Furthermore, the piezoelectric micromechanical ultrasonic transducer can be tested using an impedance analyzer to obtain, for example, Figure 6 The impedance amplitude curve shown can be used to obtain the actual anti-resonance frequency and actual resonance frequency of the piezoelectric micromechanical ultrasonic transducer.

[0061] It should be noted that the actual anti-resonance frequency refers to the secondary resonant frequency generated in a piezoelectric micromechanical ultrasonic transducer when the mechanical structure and piezoelectric material interact. This frequency is usually closely related to the transducer's operating characteristics and performance.

[0062] The actual resonant frequency refers to the resonant frequency at which a piezoelectric micromechanical ultrasonic transducer produces maximum amplitude and highest efficiency when a specific electrical signal is applied. This frequency is typically determined by the transducer's structure and materials.

[0063] The electromechanical coupling coefficient is a value that characterizes the performance of a piezoelectric micromechanical ultrasonic transducer. A larger electromechanical coupling coefficient indicates better performance, while a smaller coefficient indicates poorer performance.

[0064] Step 104: Dynamically adjust the DC voltage bias and the thickness of the top electrode to obtain the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer as the actual resonant frequency.

[0065] In this embodiment, the current resonant frequency refers to the real-time resonant frequency generated by the piezoelectric micromechanical ultrasonic transducer under different top electrode thicknesses, with a DC voltage bias applied to the transducer.

[0066] In one implementation, the DC voltage bias and the thickness of the top electrode can be dynamically adjusted. Then, the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer can be obtained by testing it with an impedance analyzer, and this frequency is taken as the actual resonant frequency. Alternatively, the piezoelectric micromechanical ultrasonic transducer can be observed in the frequency domain using a laser Doppler vibrometer to obtain the current resonant frequency corresponding to the point of maximum central displacement, which is also taken as the actual resonant frequency. See details... Figure 7 As shown.

[0067] Furthermore, time-domain observation of the piezoelectric micromechanical ultrasonic transducer can be performed using a laser Doppler vibrometer. This time-domain observation allows us to observe the complete vibration of the entire thin film under DC bias, thereby determining the change in displacement at various points on the film over time—that is, the true vibration situation. Specifically, if the piezoelectric micromechanical ultrasonic transducer only has a large displacement at its center and a small displacement around the periphery, then its sound pressure output capability is not very good; if the overall displacement of the piezoelectric micromechanical ultrasonic transducer is relatively uniform, and its vibration is similar to that of a straight up-and-down piston, then its sound pressure output is strong, and its performance is good. See details... Figure 8 As shown.

[0068] See Figure 9 As shown, by dynamically adjusting the DC voltage bias and the thickness of the top electrode, the operating performance of the piezoelectric micromechanical ultrasonic transducer under DC voltage bias can be altered. Specifically, with different top electrode thicknesses, the electric field distribution generated in the piezoelectric layer of the piezoelectric micromechanical ultrasonic transducer by applying DC bias varies, resulting in different actual vibration effects and thus different resonant frequencies. By finding a suitable top electrode thickness, the electric field generated by the electrode in the piezoelectric layer can be made more uniform, allowing the piezoelectric micromechanical ultrasonic transducer under DC voltage bias to exhibit better vibration performance, thereby improving the operating performance of the piezoelectric micromechanical ultrasonic transducer.

[0069] Step 105: Complete the performance adjustment of the piezoelectric micromechanical ultrasonic transducer.

[0070] See Figure 4As shown, the piezoelectric micromechanical ultrasonic transducer adjustment method of this application embodiment can generate a frequency change greater than 200 kHz under DC voltage bias by a piezoelectric micromechanical ultrasonic transducer with a resonant frequency of around 200 kHz. Therefore, the piezoelectric micromechanical ultrasonic transducer adjustment method of this application embodiment can enable the piezoelectric micromechanical ultrasonic transducer to operate in two modes with significantly different frequencies (such as allowing the same piezoelectric micromechanical ultrasonic transducer to operate in two modes, 200 kHz and 400 kHz, under different DC biases). This allows for flexible switching between a relatively low-frequency operating mode and a relatively high-frequency mode, meeting the requirements for high frequency matching of piezoelectric micromechanical ultrasonic transducers in certain applications and satisfying the needs of complex applications. Figure 5 As shown in the schematic diagram, the piezoelectric micromechanical ultrasonic transducer adjustment method of this application embodiment can produce a frequency change of about 0.07MHz for a piezoelectric micromechanical ultrasonic transducer with a self-designed high resonant frequency of about 4.2MHz under DC voltage bias. This proves that the method has the effect of adjusting the resonant frequency of both piezoelectric micromechanical ultrasonic transducers designed to operate in low frequency bands (such as hundreds of kHz) and those designed to operate in high frequency bands (such as several MHz).

[0071] Based on the above embodiments, in some modified embodiments, the piezoelectric micromechanical ultrasonic transducer adjustment method of this application can also adjust an array composed of multiple piezoelectric micromechanical ultrasonic transducers. This application does not make specific limitations.

[0072] The piezoelectric micromechanical ultrasonic transducer of this application includes a top electrode. By adjusting the thickness of the top electrode and dynamically applying a DC voltage bias to the piezoelectric micromechanical ultrasonic transducer, the actual resonant frequency of the piezoelectric micromechanical ultrasonic transducer is obtained. Then, the target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer is obtained. If the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching conditions, the performance adjustment of the piezoelectric micromechanical ultrasonic transducer is completed. By optimizing the thickness of the top electrode of the piezoelectric micromechanical ultrasonic transducer and applying a DC voltage bias to the piezoelectric micromechanical ultrasonic transducer, the deviation between the actual resonant frequency of the piezoelectric micromechanical ultrasonic transducer and the target resonant frequency under ideal adjustment can be reduced, thereby improving the working performance of the piezoelectric micromechanical ultrasonic transducer.

[0073] See Figure 10 This application also provides a piezoelectric micromechanical ultrasonic transducer adjustment device, which is used to perform the piezoelectric micromechanical ultrasonic transducer adjustment method described in the above embodiments. The device includes:

[0074] The first acquisition module 201 is used to acquire the target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer.

[0075] The second acquisition module 202 is used to acquire the actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer.

[0076] The judgment module 203 is used to determine whether the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching conditions.

[0077] The adjustment module 204 is used to complete the performance adjustment of the piezoelectric micromechanical ultrasonic transducer if the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching conditions; otherwise, it dynamically adjusts the DC voltage bias and the thickness of the top electrode to obtain the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer as the actual resonant frequency, and continues to execute the operation of the judgment module.

[0078] The piezoelectric micromechanical ultrasonic transducer adjustment device provided in this application embodiment is based on the same inventive concept as the piezoelectric micromechanical ultrasonic transducer adjustment method provided in the above embodiment, and has the same beneficial effects as the method used, operated or implemented.

[0079] This application also provides an electronic device corresponding to the piezoelectric micromechanical ultrasonic transducer adjustment method provided in the foregoing embodiments. Please refer to... Figure 11 This illustrates a schematic diagram of an electronic device provided by some embodiments of this application. For example... Figure 11 As shown, the electronic device 30 may include: a processor 300, a memory 301, a bus 302, and a communication interface 303. The processor 300, the communication interface 303, and the memory 301 are connected via the bus 302. The memory 301 stores a computer program that can run on the processor 300. When the processor 300 runs the computer program, it executes the piezoelectric micromechanical ultrasonic transducer adjustment method provided in any of the foregoing embodiments of this application.

[0080] The memory 301 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one physical port 303 (which can be wired or wireless), such as the Internet, wide area network, local area network, or metropolitan area network.

[0081] Bus 302 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The memory 301 is used to store programs. After receiving an execution instruction, the processor 300 executes the program. The piezoelectric micromechanical ultrasonic transducer adjustment method disclosed in any of the foregoing embodiments of this application can be applied to the processor 300, or implemented by the processor 300.

[0082] The processor 300 may be an integrated circuit with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of the processor 300 or by instructions in software form. The processor 300 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules may reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory 301. The processor 300 reads the information in memory 301 and, in conjunction with its hardware, completes the steps of the above method.

[0083] The electronic device provided in this application embodiment and the piezoelectric micromechanical ultrasonic transducer adjustment method provided in this application embodiment are based on the same inventive concept and have the same beneficial effects as the methods they adopt, operate or implement.

[0084] This application also provides a computer-readable storage medium corresponding to the piezoelectric micromechanical ultrasonic transducer adjustment method provided in the foregoing embodiments, wherein a computer program (i.e., a program product) is stored thereon. When the computer program is run by a processor, it executes the piezoelectric micromechanical ultrasonic transducer adjustment method provided in any of the foregoing embodiments.

[0085] It should be noted that examples of the computer-readable storage medium may also include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other optical and magnetic storage media, which will not be elaborated here.

[0086] This application also provides a computer program product corresponding to the piezoelectric micromechanical ultrasonic transducer adjustment method provided in the foregoing embodiments, including a computer program that is executed by a processor to implement the piezoelectric micromechanical ultrasonic transducer adjustment method provided in the above embodiments.

[0087] The computer-readable storage medium and computer program product provided in the above embodiments of this application are based on the same inventive concept as the piezoelectric micromechanical ultrasonic transducer adjustment method provided in the embodiments of this application, and have the same beneficial effects as the methods adopted, run or implemented by the application programs stored therein.

[0088] It should be noted that:

[0089] The algorithms and displays provided herein are not inherently related to any particular computer, virtual device, or other equipment. Various general-purpose devices can also be used in conjunction with the teachings herein. The required structure for constructing such devices is apparent from the above description. Furthermore, this application is not directed to any particular programming language. It should be understood that the content of this application described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of this application.

[0090] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0091] Similarly, it should be understood that, in order to simplify this application and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of this application, various features of this application are sometimes grouped together into a single embodiment, figure, or description thereof. However, this method of disclosure should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0092] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0093] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0094] The various component embodiments of this application can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some or all of the components in the virtual machine creation apparatus according to embodiments of this application. This application can also be implemented as a device or apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such an implementation of this application can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0095] It should be noted that the above embodiments are illustrative of this application and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses 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. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims 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 can be interpreted as names.

[0096] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for adjusting a piezoelectric micromechanical ultrasonic transducer, wherein the piezoelectric micromechanical ultrasonic transducer includes a top electrode, characterized in that, include: Obtain the target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer; Obtain the actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer; Determine whether the degree of matching between the actual resonant frequency and the target resonant frequency meets the preset matching conditions; If the conditions are met, the performance adjustment of the piezoelectric micromechanical ultrasonic transducer is completed; Otherwise, dynamically adjust the DC voltage bias and the thickness of the top electrode to obtain the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer as the actual resonant frequency, and continue to execute the step of determining whether the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching conditions.

2. The method for adjusting a piezoelectric micromechanical ultrasonic transducer according to claim 1, characterized in that, The process of obtaining the target resonant frequency without applying a DC voltage bias to the piezoelectric micromechanical ultrasonic transducer includes: The mass density, bending stiffness, and shape of the piezoelectric micromechanical ultrasonic transducer were obtained. Based on the shape, the length attribute of the piezoelectric micromechanical ultrasonic transducer is obtained; The target resonant frequency is obtained based on the mass density, the bending stiffness, and the length attribute.

3. The method for adjusting a piezoelectric micromechanical ultrasonic transducer according to claim 1, characterized in that, The acquisition of the actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer includes: The internal stress generated by the piezoelectric micromechanical ultrasonic transducer is obtained; Based on the mass density, length properties, and internal stress of the piezoelectric micromechanical ultrasonic transducer, the actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer is obtained.

4. The method for adjusting a piezoelectric micromechanical ultrasonic transducer according to claim 3, characterized in that, The piezoelectric micromechanical ultrasonic transducer further includes a piezoelectric layer, and the step of obtaining the internal stress generated by the piezoelectric micromechanical ultrasonic transducer includes: Obtain the piezoelectric coefficient of the thin film in the top electrode; The elastic compliance coefficient and thickness of the piezoelectric material in the piezoelectric layer are obtained, wherein the elastic compliance coefficient includes a first elastic compliance coefficient in the x-direction and a second elastic compliance coefficient in the y-direction per unit area; Based on the piezoelectric coefficient, the first elastic flexibility coefficient, the second elastic flexibility coefficient, the thickness, and the DC voltage bias, the in-plane stress per unit area of ​​the piezoelectric micromechanical ultrasonic transducer is calculated using the following formula; The average value of each in-plane stress is taken as the internal stress generated by the piezoelectric micromechanical ultrasonic transducer. The formula includes: in, This represents the in-plane stress. This represents the piezoelectric coefficient. This represents the first elastic compliance coefficient. V represents the second flexibility coefficient, and V represents the DC voltage bias. This indicates the thickness.

5. The method for adjusting a piezoelectric micromechanical ultrasonic transducer according to any one of claims 1-4, characterized in that, If the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching condition, then the performance adjustment of the piezoelectric micromechanical ultrasonic transducer is completed, including: If the difference between the actual resonant frequency and the target resonant frequency is less than or equal to a preset threshold, the performance adjustment of the piezoelectric micromechanical ultrasonic transducer is completed.

6. The method for adjusting a piezoelectric micromechanical ultrasonic transducer according to claim 5, characterized in that, Also includes: Obtain the actual anti-resonance frequency of the piezoelectric micromechanical ultrasonic transducer; Based on the actual resonant frequency and the actual anti-resonant frequency, the electromechanical coupling coefficient of the piezoelectric micromechanical ultrasonic transducer is calculated; If the electromechanical coupling coefficient is greater than or equal to a preset coefficient threshold, the performance adjustment of the piezoelectric micromechanical ultrasonic transducer is completed.

7. A piezoelectric micromechanical ultrasonic transducer adjustment device, wherein the piezoelectric micromechanical ultrasonic transducer includes a top electrode, characterized in that, include: The first acquisition module is used to acquire the target resonant frequency when no DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer. The second acquisition module is used to acquire the actual resonant frequency when a DC voltage bias is applied to the piezoelectric micromechanical ultrasonic transducer. The judgment module is used to determine whether the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching conditions. The adjustment module is used to complete the performance adjustment of the piezoelectric micromechanical ultrasonic transducer if the matching degree between the actual resonant frequency and the target resonant frequency meets the preset matching conditions; otherwise, it dynamically adjusts the DC voltage bias and the thickness of the top electrode to obtain the current resonant frequency of the piezoelectric micromechanical ultrasonic transducer as the actual resonant frequency, and continues to execute the operation of the judgment module.

8. A piezoelectric micromechanical ultrasonic transducer, comprising the piezoelectric micromechanical ultrasonic transducer adjustment device as described in claim 6, characterized in that, Also includes: A piezoelectric layer, wherein the thickness of the piezoelectric layer is less than or equal to 2 micrometers.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1-6.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1-6.

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