CN116159731A - Piezoelectric micromechanical ultrasonic transducer and ultrasonic detection system - Google Patents
Piezoelectric micromechanical ultrasonic transducer and ultrasonic detection system Download PDFInfo
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 3
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
- B06B1/0607—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements
- B06B1/0622—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements on one surface
- B06B1/0629—Square array
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
Abstract
The invention discloses a piezoelectric micro-mechanical ultrasonic transducer and an ultrasonic detection system, wherein the piezoelectric micro-mechanical ultrasonic transducer comprises a PMUT array element formed on a substrate, and the PMUT array element is at least used for transmitting and receiving first frequency ultrasonic waves and second frequency ultrasonic waves, wherein the frequency of the first frequency ultrasonic waves is smaller than that of the second frequency ultrasonic waves. The piezoelectric micromachined ultrasonic transducer is applied to an ultrasonic detection system, and utilizes PMUT array elements to firstly transmit and receive first frequency ultrasonic waves (low-frequency ultrasonic signals) so as to detect a target object in a long-distance large range, determine the approximate direction of the target object, and then transmit and receive second frequency ultrasonic waves (high-frequency ultrasonic signals) after the target object approaches the target object so as to detect the specific morphology of the target object in a short distance, thereby realizing that the resolution of detection of the object in the short distance is improved while the detection distance is increased.
Description
Technical Field
The invention relates to the technical field of ultrasonic detection, in particular to a piezoelectric micromechanical ultrasonic transducer and an ultrasonic detection system.
Background
Along with the development of micromachining technology, piezoelectric Micromachined Ultrasonic Transducers (PMUTs) are widely researched and innovated and developed in the field of ultrasonic detection due to the characteristics of small volume, low power consumption, high sensitivity, mass production, easiness in circuit integration, array realization and the like.
The PMUT ultrasonic detection technology is an active obstacle detection technology, has the characteristics of low cost, low power consumption, wide sensing range, no need of on-site maintenance, no influence of object colors, suitability for dark environments and the like, and is expected to be applied to the scenes of blind person guiding, micro-robot target positioning, recognition and the like. Through the research of technicians, the detection imaging and positioning of the PMUT in the air can be realized by utilizing a beam synthesis technology.
The existing ultrasonic detection technology adopts ultrasonic signals with single frequency for detection, however, the single-frequency ultrasonic detection has the defects of low imaging resolution or short detection distance.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.
Disclosure of Invention
The invention aims to provide a piezoelectric micromechanical ultrasonic transducer and an ultrasonic detection system, which are used for solving the technical problems of low imaging resolution or short detection distance in the single-frequency ultrasonic detection technology.
To achieve the above object, an embodiment of the present invention provides a piezoelectric micromachined ultrasonic transducer, which includes a PMUT array element formed on a substrate, the PMUT array element being at least configured to transmit and receive a first frequency ultrasonic wave and a second frequency ultrasonic wave, wherein a frequency of the first frequency ultrasonic wave is smaller than a frequency of the second frequency ultrasonic wave.
In one or more embodiments of the present invention, the PMUT array element transmits and receives a first frequency ultrasonic wave in a first order resonance state and a second frequency ultrasonic wave in a higher order resonance state.
In one or more embodiments of the present invention, the PMUT array elements include a first PMUT array element and a second PMUT array element, wherein the first PMUT array element is at least configured to transmit and receive a first frequency ultrasound wave, and the second PMUT array element is at least configured to transmit and receive a second frequency ultrasound wave.
In one or more embodiments of the present invention, the first frequency ultrasonic wave has a frequency range of 20kHz to 100kHz, and the second frequency ultrasonic wave has a frequency range of 100kHz to 400kHz.
In one or more embodiments of the present invention, the PMUT array element includes a cavity formed on the substrate, and a diaphragm covered over the cavity, where the diaphragm includes a support layer, a lower electrode, a piezoelectric layer, and an upper electrode that are sequentially stacked.
In one or more embodiments of the present invention, the material of the lower electrode is one of molybdenum, gold, platinum, aluminum, or tin.
In one or more embodiments of the present invention, the material of the upper electrode is one of gold, molybdenum, platinum, aluminum, or tin.
In one or more embodiments of the present invention, the material of the piezoelectric layer is scandium-doped aluminum nitride, zinc oxide, or lead zirconate titanate piezoelectric ceramic.
In one or more embodiments of the present invention, the support layer includes a first support layer and a second support layer that are stacked, where a material of the first support layer is silicon oxide, and a material of the second support layer is silicon.
In another aspect of the present invention, there is also provided an ultrasonic detection system including:
the piezoelectric micromechanical ultrasonic transducer is at least used for sending and receiving first frequency ultrasonic waves and second frequency ultrasonic waves, wherein the frequency of the first frequency ultrasonic waves is smaller than that of the second frequency ultrasonic waves;
the ultrasonic wave emission driving unit is electrically connected with the piezoelectric micromechanical ultrasonic transducer and is used for driving the piezoelectric micromechanical ultrasonic transducer to send first-frequency ultrasonic waves and second-frequency ultrasonic waves;
the ultrasonic processing unit is electrically connected with the piezoelectric micro-mechanical ultrasonic transducer and is used for processing the first frequency ultrasonic wave and the second frequency ultrasonic wave received by the piezoelectric micro-mechanical ultrasonic transducer;
the control unit is respectively connected with the ultrasonic emission driving unit and the ultrasonic processing unit and is used for controlling the ultrasonic emission driving unit and the ultrasonic processing unit to work based on driving signals; and
and the storage unit is respectively connected with the control unit and the ultrasonic processing unit and is used for storing the driving signal and the first frequency ultrasonic wave and the second frequency ultrasonic wave fed back by the ultrasonic processing unit.
Compared with the prior art, the piezoelectric micromachined ultrasonic transducer according to the embodiment of the invention is applied to the ultrasonic detection system of the invention, and utilizes the PMUT array element to firstly transmit and receive the first frequency ultrasonic wave (low-frequency ultrasonic wave signal) so as to detect the target object in a long-distance large range, and after the approximate direction of the target object is determined and the target object is close to the target object, the second frequency ultrasonic wave (high-frequency ultrasonic wave signal) is transmitted and received so as to detect the specific morphology of the target object in a short distance, thereby realizing that the resolution of detecting the object in the short distance is improved while the detection distance is increased.
Drawings
Fig. 1 is a schematic structural diagram of a piezoelectric micromachined ultrasonic transducer according to a first embodiment of the present invention;
fig. 2 is a graph showing the variation of the steady-state vibration phase amplitude of a single PMUT array element in a piezoelectric micromachined ultrasonic transducer according to the first embodiment of the present invention at different resonance frequencies;
fig. 3 is a graph showing the variation of the steady-state vibration phase amplitude of a single PMUT array element in a piezoelectric micromachined ultrasonic transducer according to the first embodiment of the present invention at different resonance frequencies within the fundamental frequency range;
fig. 4 is a schematic diagram of PMUT beam synthesis of an ultrasound probe system according to a first embodiment of the present invention;
fig. 5 is a schematic distribution diagram of a first PMUT array element and a second PMUT array element in a piezoelectric micromachined ultrasonic transducer according to a second embodiment of the present invention;
FIG. 6 is a schematic diagram of an ultrasound probe system according to a third embodiment of the present invention;
FIG. 7 is a schematic diagram of a simulated ultrasound detection scenario of an ultrasound detection system according to a third embodiment of the present invention;
fig. 8 is a schematic diagram of a detection flow of an ultrasonic detection system according to a third embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the invention is, therefore, to be taken in conjunction with the accompanying drawings, and it is to be understood that the scope of the invention is not limited to the specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or components.
Example 1
Referring to fig. 1, an embodiment of the piezoelectric micromachined ultrasonic transducer of the present invention is described, in which the piezoelectric micromachined ultrasonic transducer includes PMUT array elements formed on a substrate 111, the PMUT array elements are of a thin film structure, and the thin film structure of the array elements is vibrated to emit ultrasonic waves by using pulse wave excitation through a reverse piezoelectric effect; the array element film structure can receive ultrasonic waves to deform through the piezoelectric effect, so that a voltage signal of ultrasonic echo is generated.
Specifically, the PMUT array element includes a cavity 112 formed on a substrate 111 and a diaphragm covered above the cavity 112, where the diaphragm includes a support layer, a lower electrode 115, a piezoelectric layer 116, and an upper electrode 117 that are sequentially stacked, and the support layer includes a first support layer 113 and a second support layer 114 that are stacked.
In some embodiments, the material of the first support layer 113 may be silicon oxide, and the material of the second support layer 114 may be silicon; the material of the lower electrode 115 may be one of molybdenum, gold, platinum, aluminum, or tin, and the material of the upper electrode 117 may be one of gold, molybdenum, platinum, aluminum, or tin; the material of the piezoelectric layer 116 may be scandium-doped aluminum nitride, zinc oxide, or lead zirconate titanate piezoelectric ceramic.
Here, the shape of the PMUT array element may be circular, rectangular, square, polygonal, or the like. The materials of each structural layer of the PMUT array element can be changed according to actual requirements, and the thickness and the size of each structural layer can also be changed.
The PMUT array element is at least used for sending and receiving the first frequency ultrasonic wave and the second frequency ultrasonic wave.
In this embodiment, the first frequency ultrasonic wave and the second frequency ultrasonic wave may be transmitted and received by the same PMUT array element, which may specifically be: the PMUT array element transmits and receives a first frequency ultrasonic wave (low frequency ultrasonic wave signal) in its first order resonance state, and transmits and receives a second frequency ultrasonic wave (high frequency ultrasonic wave signal) in its high order resonance state.
Further, the frequency range of the first frequency ultrasonic wave may be 20kHz to 100kHz, and the frequency range of the second frequency ultrasonic wave may be 100kHz to 400kHz.
In this embodiment, the impedance analyzer is used to sweep the frequency of a single PMUT array element on the substrate 111 (from 100kHz to 6 MHz), so as to obtain a variation diagram of the steady-state vibration phase amplitude of the PMUT array element under different resonance frequencies as shown in fig. 2.
As can be seen from fig. 2, one PMUT array element has a multi-order resonance frequency (where F1 is a first-order resonance frequency, i.e. a fundamental frequency), and the vibration phase amplitudes of the PMUT array element at different resonance frequencies are also different, and the vibration phase amplitudes at the first-order resonance frequency (fundamental frequency) are the largest.
Therefore, the frequency conversion of the piezoelectric micromechanical ultrasonic transducer can be realized by selecting different order harmonic frequencies of PMUT array elements, so that the high-precision ultrasonic detection function of the piezoelectric micromechanical ultrasonic transducer in a three-dimensional space in a multi-frequency vibration mode is realized.
On the other hand, the impedance analyzer is utilized again to sweep the fundamental frequency range of a single PMUT array element (from 100kHz to 130 kHz), so that a variation diagram of the steady-state vibration phase amplitude of the PMUT array element in different resonance frequencies in the fundamental frequency range can be obtained as shown in fig. 3.
As can be seen from fig. 3, the frequency conversion of the piezoelectric micromechanical ultrasonic transducer can be achieved by converting the frequency in the range of the first-order resonant frequency of a PMUT array element at the first-order resonant frequency.
In terms of ultrasound detection, ultrasound signals of different frequencies may be used to detect objects within different distance ranges. As shown in fig. 4, delay pulses are applied to PMUT array elements by a beam forming technique, and deflection focusing (direction) of beams is controlled by utilizing huyghen principle, so that the PMUT array elements transmit or receive ultrasonic waves in a specific direction to detect a target object.
Here, the beam deflection direction may be changed to two acoustic beams whose beam directions differ by 60 °, delay time of 20ns, or to a plurality of acoustic beams of different deflection angles, different delay times, or the like.
In this embodiment, the first frequency ultrasonic wave transmitted and received by the same PMUT array element in its first-order resonance state is a low-frequency ultrasonic wave signal, which can be used to detect a target object in a long distance; the second frequency ultrasonic wave transmitted and received in the high-order resonance state is a high-frequency ultrasonic wave signal, and can be used for detecting the specific morphological structure of the target object in a short distance. The two are combined, so that the accurate detection of the target object in the three-dimensional space can be realized.
Example two
Referring to fig. 5, an embodiment of the piezoelectric micromachined ultrasonic transducer of the present invention is described, which is substantially the same as that of the first embodiment, except that: in this embodiment, the first frequency ultrasonic waves and the second frequency ultrasonic waves may be transmitted and received by PMUT array elements of different sizes.
Specifically, in this embodiment, the PMUT array element includes a first PMUT array element 101 and a second PMUT array element 102, where the first PMUT array element 101 is at least used for transmitting and receiving the first frequency ultrasonic wave, and the second PMUT array element 102 is at least used for transmitting and receiving the second frequency ultrasonic wave.
In this embodiment, the number and arrangement of the first PMUT array element 101 and the second PMUT array element 102 may be designed according to actual requirements. Illustratively, the first PMUT array element 101 may be distributed around the periphery of the second PMUT array element 102, i.e. the arrangement shown in fig. 5; the first PMUT array element 101 may be distributed inside the second PMUT array element 102; or the first PMUT array element 101 and the second PMUT array element 102 are mixed and uniformly distributed; other arrangements may also be included.
In this embodiment, the first PMUT array element 101 and the second PMUT array element 102 may be circular, and the radius size of the first PMUT array element 101 is larger than the radius size of the second PMUT array element 102. The larger the radius of the PMUT array element, the lower the fundamental frequency (first order resonant frequency) thereof, with the other structure unchanged. Thus, in the present embodiment, the first PMUT element 101 is at least for transmitting and receiving a first frequency ultrasonic wave (low frequency ultrasonic wave signal), and the second PMUT element 102 is at least for transmitting and receiving a second frequency ultrasonic wave (high frequency ultrasonic wave signal).
It should be noted that, the size and shape of the PMUT array element in this embodiment may be changed according to actual needs; meanwhile, the fundamental frequency bandwidth of PMUT array elements may be changed by structural changes.
In this embodiment, the first frequency ultrasonic wave transmitted and received by the first PMUT array element 101 is a low frequency ultrasonic wave signal, which can be used to detect a target object in a long distance; the second frequency ultrasonic wave transmitted and received by the second PMUT array element 102 is a high frequency ultrasonic wave signal, which can be used for detecting the specific morphology structure of the target object in a short distance; the two are combined, so that the accurate detection of the target object in the three-dimensional space can be realized.
Furthermore, for PMUT array elements with different shapes, the frequency of the PMUT array elements can be changed, and the frequency conversion of the piezoelectric micro-mechanical ultrasonic transducer can be realized.
Example III
Referring to fig. 6, an embodiment of the ultrasonic detection system of the present invention is described, in which the ultrasonic detection system includes a piezoelectric micromechanical ultrasonic transducer 10, an ultrasonic emission driving unit 20, an ultrasonic processing unit 30, a control unit 40, and a storage unit 50. In practical applications, the ultrasonic detection system may be loaded on an off-board mobile device (e.g., a remote control car, a remote control drone, etc.).
The piezoelectric micromechanical ultrasonic transducer 10 is at least used for transmitting and receiving a first frequency ultrasonic wave and a second frequency ultrasonic wave, and is used for detecting targets in different distance ranges. The specific principles of which have been described in detail above and are not repeated here.
The piezoelectric micromachined ultrasonic transducer 10 in the present embodiment may also be replaced with a ceramic ultrasonic transducer.
The ultrasonic wave emission driving unit 20 is electrically connected with the piezoelectric micro-mechanical ultrasonic transducer 10, and is used for driving the piezoelectric micro-mechanical ultrasonic transducer 10 to send the first frequency ultrasonic wave and the second frequency ultrasonic wave.
In this embodiment, the ultrasonic wave transmitting driving unit 20 mainly includes a voltage driving circuit, and after the control unit 40 reads the driving signals with specific frequency, pulse width and time delay stored in the storage unit 50, a transmitting pulse waveform with a certain amplitude is generated by the voltage driving circuit, and the waveform is applied to the piezoelectric micro-mechanical ultrasonic transducer 10, so as to drive the piezoelectric micro-mechanical ultrasonic transducer 10 to transmit the ultrasonic wave with the first frequency and/or the ultrasonic wave with the second frequency.
Illustratively, in this embodiment, the driving signal for stimulating the PMUT array element to transmit the first frequency ultrasonic wave (low frequency ultrasonic signal) may be a pulse square wave with a period of 15 and a frequency of lower frequency (90 kHz); the driving signal for stimulating the PMUT array element to transmit the second frequency ultrasonic wave (high frequency ultrasonic signal) may be a pulse square wave with a period of 15 and a frequency of high frequency (200 kHz).
The ultrasonic processing unit 30 is electrically connected to the piezoelectric micro-mechanical ultrasonic transducer 10, and is configured to process the first frequency ultrasonic wave and the second frequency ultrasonic wave received by the piezoelectric micro-mechanical ultrasonic transducer 10.
In this embodiment, the ultrasonic processing unit 30 mainly integrates circuits such as filtering, amplifying, and beam forming, and is configured to process echo signals of the first frequency ultrasonic wave and the second frequency ultrasonic wave, and feed back the processed echo signals to the control unit 40 and the storage unit 50, and the control unit 40 may determine whether a target object exists or not according to the echo signals.
And a control unit 40 connected to the ultrasonic wave emission driving unit 20 and the ultrasonic wave processing unit 30, respectively, for controlling the operation of the ultrasonic wave emission driving unit 20 and the ultrasonic wave processing unit 30 based on the driving signals.
In this embodiment, the control unit 40 mainly includes a Microcontroller (MCU) or FPGA, which can determine whether a target object exists in the detection field according to the echo signal, and can determine the size, speed, shape, distance between the target object and the like of the target object through information such as intensity, doppler shift, spectral characteristics, time delay, and the like of the echo when the target object is determined.
The storage unit 50 is connected to the control unit 40 and the ultrasonic processing unit 30, and is used for storing the driving signal and the first frequency ultrasonic wave and the second frequency ultrasonic wave fed back by the ultrasonic processing unit 30.
The circuitry of the ultrasound probe system in this embodiment may be implemented as board level circuitry, or as application specific integrated circuits, etc.
Fig. 7 and 8 show a use scenario of the ultrasonic detection system and an ultrasonic detection flow thereof, respectively.
Referring to fig. 7 and 8, when detecting an object at a long distance L1, the control unit 40 reads the low frequency (20-100 kHz) pulse waveform data with a certain delay period of 5-20 stored in the storage unit 50, drives the ultrasonic wave transmission driving unit 20 to generate a low frequency pulse waveform with an amplitude of 4V, applies the low frequency pulse waveform to the piezoelectric micromechanical ultrasonic transducer 10, and stimulates the piezoelectric micromechanical ultrasonic transducer to transmit a first frequency ultrasonic wave (low frequency ultrasonic wave signal) with a frequency F1.
The ultrasonic processing unit 30 receives and processes the echo signal, and feeds back to the control unit 40 and the storage unit 50. The control unit 40 judges whether a target object exists in the detection view field according to the echo signal, if no target object information exists, the operator controls the external mobile equipment to move, and simultaneously, the low-frequency ultrasonic signal is emitted again to detect the target object; if the presence of the target object is detected, the control unit 40 may determine the size, speed, shape, distance from the target object, etc. of the target object through information such as intensity, doppler shift, spectral characteristics, time delay, etc. of the echo.
After determining the general direction of the target object, the operator can control the external mobile device to approach the target object, when the external mobile device approaches to a certain distance L2 (e.g. less than 50 cm), the control unit 40 reads the stored high-frequency (100-400 kHz), certain pulse width and delayed waveform data in the storage unit 50, and then drives the voltage driving circuit of the ultrasonic emission driving unit 20 to generate a high-frequency pulse waveform with the amplitude of 4V, and applies the high-frequency pulse waveform to the piezoelectric micromechanical ultrasonic transducer 10 to stimulate the ultrasonic emission of the second frequency ultrasonic wave (high-frequency ultrasonic signal) with the frequency of F2.
The ultrasonic processing unit 30 receives and processes the echo signal, and feeds back to the control unit 40 and the storage unit 50. The control unit 40 may finally obtain a specific size morphology of the target object by performing image processing on the echo information.
When the target object is detected in a short distance, the piezoelectric micromechanical ultrasonic transducer 10 can simultaneously transmit and receive a high-frequency ultrasonic signal and a low-frequency ultrasonic signal for detection.
In this embodiment, the high-frequency ultrasonic signal and the low-frequency ultrasonic signal may be generated by the fundamental frequency (first-order resonant frequency) and the high-order resonant frequency of the same PMUT array element in the piezoelectric micromechanical ultrasonic transducer 10, or may be generated by a large-radius PMUT array element (e.g., the first PMUT array element 101) and a small-radius PMUT array element (e.g., the second PMUT array element 102) in the piezoelectric micromechanical ultrasonic transducer 10.
In this embodiment, the off-board mobile device may be controlled by a remote control device. And the control unit 40 of the ultrasonic detection system communicates with a remote control device, which may further include a display unit for displaying the detection scenario of the ultrasonic detection system in real time.
The foregoing descriptions of specific exemplary embodiments of the present invention are presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application to thereby enable one skilled in the art to make and utilize the invention in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (10)
1. A piezoelectric micromachined ultrasonic transducer comprising a PMUT array element formed on a substrate, the PMUT array element configured to transmit and receive at least a first frequency ultrasonic wave and a second frequency ultrasonic wave, wherein the first frequency ultrasonic wave has a frequency less than a frequency of the second frequency ultrasonic wave.
2. The piezoelectric micromachined ultrasonic transducer of claim 1, wherein the PMUT element transmits and receives ultrasonic waves of a first frequency in a first order resonance state and transmits and receives ultrasonic waves of a second frequency in a higher order resonance state.
3. The piezoelectric micromachined ultrasonic transducer of claim 1, wherein the PMUT array elements comprise a first PMUT array element and a second PMUT array element, wherein the first PMUT array element is configured to transmit and receive at least a first frequency ultrasonic wave and the second PMUT array element is configured to transmit and receive at least a second frequency ultrasonic wave.
4. The piezoelectric micromachined ultrasonic transducer according to claim 1, wherein the frequency range of the first frequency ultrasonic wave is 20kHz to 100kHz, and the frequency range of the second frequency ultrasonic wave is 100kHz to 400kHz.
5. The piezoelectric micromachined ultrasonic transducer of claim 1, wherein the PMUT array element comprises a cavity formed on the substrate and a diaphragm overlying the cavity, the diaphragm comprising a support layer, a lower electrode, a piezoelectric layer, and an upper electrode, which are stacked in sequence.
6. The piezoelectric micromachined ultrasonic transducer of claim 5, wherein the material of the lower electrode is one of molybdenum, gold, platinum, aluminum, or tin.
7. The piezoelectric micromachined ultrasonic transducer of claim 5, wherein the upper electrode is one of gold, molybdenum, platinum, aluminum, or tin.
8. The piezoelectric micromachined ultrasonic transducer of claim 5, wherein the piezoelectric layer is made of scandium-doped aluminum nitride, zinc oxide, or lead zirconate titanate piezoelectric ceramic.
9. The piezoelectric micromachined ultrasonic transducer of claim 5, wherein the support layer comprises a first support layer and a second support layer that are stacked, the first support layer being of silicon oxide and the second support layer being of silicon.
10. An ultrasonic detection system, comprising:
the piezoelectric micromachined ultrasonic transducer of any of claims 1 to 9, for transmitting and receiving at least a first frequency ultrasonic wave and a second frequency ultrasonic wave, wherein the frequency of the first frequency ultrasonic wave is smaller than the frequency of the second frequency ultrasonic wave;
the ultrasonic wave emission driving unit is electrically connected with the piezoelectric micromechanical ultrasonic transducer and is used for driving the piezoelectric micromechanical ultrasonic transducer to send first-frequency ultrasonic waves and second-frequency ultrasonic waves;
the ultrasonic processing unit is electrically connected with the piezoelectric micro-mechanical ultrasonic transducer and is used for processing the first frequency ultrasonic wave and the second frequency ultrasonic wave received by the piezoelectric micro-mechanical ultrasonic transducer;
the control unit is respectively connected with the ultrasonic emission driving unit and the ultrasonic processing unit and is used for controlling the ultrasonic emission driving unit and the ultrasonic processing unit to work based on driving signals; and
and the storage unit is respectively connected with the control unit and the ultrasonic processing unit and is used for storing the driving signal and the first frequency ultrasonic wave and the second frequency ultrasonic wave fed back by the ultrasonic processing unit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310217945.8A CN116159731A (en) | 2023-03-08 | 2023-03-08 | Piezoelectric micromechanical ultrasonic transducer and ultrasonic detection system |
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| CN202310217945.8A CN116159731A (en) | 2023-03-08 | 2023-03-08 | Piezoelectric micromechanical ultrasonic transducer and ultrasonic detection system |
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| CN202310217945.8A Pending CN116159731A (en) | 2023-03-08 | 2023-03-08 | Piezoelectric micromechanical ultrasonic transducer and ultrasonic detection system |
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