JP6948216B2 - Ultrasonic transmitter / receiver and ultrasonic transducer - Google Patents

Description

The present invention relates to an ultrasonic transmitter / receiver and an ultrasonic transducer.

Conventionally, there are various ultrasonic transmission / reception devices such as a sonar and a medical ultrasonic diagnostic device. In these ultrasonic transmission / reception devices, a matching layer for matching the acoustic impedance of the piezoelectric element and the subject is usually provided. For example, Patent Document 1 describes an ultrasonic transducer having an acoustic matching layer laminated with a material such as an epoxy resin.

Japanese Unexamined Patent Publication No. 2016-2196662

In order to improve the performance of the acoustic element of the ultrasonic transmitter / receiver, it is necessary to suppress the reflection of sound waves between different materials as much as possible, and matching the acoustic impedance at the material interface is very important. In Patent Document 1, in order to match the acoustic impedance, the thickness of the matching layer composed of a plurality of matching layers is adjusted to be 1/4 of the working frequency.

However, in the case of the matching layer described in Patent Document 1, it is necessary to change the thickness of the matching layer and the material used according to the material of the subject, and it is difficult to match the acoustic impedance in a wide frequency band. Met. Further, while the acoustic impedance can be matched more accurately as the number of layers increases, the thickness of the matching layer increases, which makes it difficult to miniaturize the device.

An object of the present invention is to provide an ultrasonic transmitter / receiver and an ultrasonic transducer capable of accurately matching acoustic impedance in a wide frequency band while realizing miniaturization.

The ultrasonic transmission / reception device according to the present invention supports a first member having a first electrode, a second member having a second electrode, the first member, and the second member. It is provided with a matching layer having a cell in which a gap is formed by the supporting member, and a control unit that controls the applied voltage to change the contact area between the first member and the second member. It is configured as a characteristic ultrasonic transmitter / receiver.

The present invention is also understood as an ultrasonic transducer used in the ultrasonic transmitter / receiver.

According to the present invention, it is possible to accurately match the acoustic impedance in a wide frequency band while realizing miniaturization.

It is a figure which shows the configuration example of the ultrasonic wave transmission / reception device. It is a figure which shows the structural example of an ultrasonic transducer. It is a figure which shows the structural example of the matching layer shown in FIG. It is a figure which shows the structural example of the cell shown in FIG. It is a figure which shows the structural example of a cell at the time of voltage control. It is a figure which shows the example of the change of the contact area of a cell at the time of voltage control. It is a figure which shows the structural example of the cell shown in FIG. 3 (another example). It is a figure which shows the structural example of a cell at the time of voltage control (another example). It is a figure which shows the example of the change of the contact area of a cell at the time of voltage control (another example). It is a figure which shows the example of the applied voltage control table which defined the control method of the applied voltage. It is a figure which shows the configuration example of the ultrasonic wave transmission / reception device (when one power source is provided). It is a figure which shows the configuration example of the ultrasonic wave transmission / reception device (when the power source is provided for each cell). It is a figure which shows the configuration example of the ultrasonic wave transmission / reception device (in the case of feedback control).

Hereinafter, embodiments of the ultrasonic transmitter / receiver and the ultrasonic transducer will be described in detail with reference to the accompanying drawings. In the following, as an example, an ultrasonic transmitter / receiver applied to an ultrasonic transducer of a capacitance type device (CMUT (Capacitive Micromachined Ultrasonic Transducer) device) is described in a matching layer composed of acoustic elements. However, it can be applied to devices and devices having similar functions. Further, in the following, unless otherwise specified, the same components are designated by the same reference numerals and the description thereof is omitted.

FIG. 1 is a diagram showing a configuration example of the ultrasonic wave transmission / reception device 100. As shown in FIG. 1, the ultrasonic transmission / reception device 100 includes an ultrasonic transformer 12, a circuit unit 13, and a control display unit 14.

The ultrasonic transducer 12 is an ultrasonic probe that transmits ultrasonic waves and receives reflected waves. The ultrasonic transducer 12 is electrically connected to the circuit unit 13, generates ultrasonic waves based on a drive signal supplied from the transmission circuit 133 of the circuit unit 13, and reflects waves from a subject (not shown). Is received and the received reflected wave is converted into an electric signal.

When ultrasonic waves are transmitted from the ultrasonic transducer 12 to the subject, the transmitted ultrasonic waves are reflected one after another on the discontinuous surface of the acoustic impedance of the subject, and the transmitted ultrasonic waves are reflected one after another by the ultrasonic transducer. 12 receives the reflected wave. The reflected wave is converted into a reflected wave signal, which is an electric signal, by the ultrasonic transducer 12 that has received the reflected wave. The amplitude of the reflected wave signal depends on the difference in acoustic impedance in the discontinuity where the ultrasonic waves are reflected.

As shown in FIG. 1, the ultrasonic transducer 12 includes one or a plurality of matching layers 121 and a piezoelectric element 122. In FIG. 1, N matching layers from the first matching layer to the Nth matching layer are provided, and the number thereof should be appropriately determined according to the usage environment of the ultrasonic transmitter / receiver and the medium such as the subject. Can be done.

Each matching layer 121 is a member that alleviates the mismatch of acoustic impedance between the piezoelectric element 122 and the subject so that the ultrasonic waves radiated from the piezoelectric element 122 are efficiently incident on the subject. It is provided on the acoustic radiation surface side of the piezoelectric element 122 (the surface of the piezoelectric element 122 that emits ultrasonic waves). As the member of each matching layer 121, for example, a resin such as an epoxy resin or a silicone resin, a metal such as aluminum or an alloy thereof, or an inorganic material such as silicon which is a semiconductor or a compound thereof can be used. The structure of each matching layer 121 is changed according to the magnitude of the value of the voltage applied from the power supply 131 corresponding to each matching layer 121 provided in the circuit unit 13. The specific configuration and structural changes of each matching layer 121 will be described later.

The piezoelectric element 122 is composed of, for example, a piezoelectric element such as piezoelectric ceramics or an electrostrictive element. As a member of the piezoelectric element 122, for example, PZT (lead zirconate titanate / Pb (Zr, Ti) O3) and PMN-PT (lead magnesium niobate-lead titanate / Pb (Mg1 /)) have piezoelectricity. 3Nb2 / 3) O3-PbTiO3) can be used. The piezoelectric element 122 emits ultrasonic waves according to the drive signal supplied from the transmission circuit 133 of the circuit unit 13, and converts the reflected wave received from the subject into a reflected wave signal (voltage signal), and the converted reflected wave. The signal is output to the receiving circuit 134 of the circuit unit 13. The specific physical structure of the ultrasonic transducer 12 will be described later. Subsequently, the circuit unit 13 will be described.

The circuit unit 13 is a circuit that controls the transmission and reception of ultrasonic waves by the ultrasonic transformer 12 and controls the voltage applied to each matching layer 121. As shown in FIG. 1, the circuit unit 13 includes one or a plurality of power supplies 131 provided corresponding to each matching layer 121, a voltage control unit 132 that controls the applied voltage of each power supply 131, and a control display unit. The transmission circuit 133 that supplies the drive signal to the ultrasonic transformer 12 according to the instruction from 14, and the reflected wave data generated by the ultrasonic transformer 12 are subjected to various processing. Is configured to include a receiving circuit 134 for generating and outputting to the control display unit 14.

Each power supply 131 is composed of, for example, a DC power supply circuit, and applies a voltage to the matching layer 121 corresponding to each power supply 131 according to an instruction from the voltage control unit 132.

The voltage control unit 132 is composed of, for example, a voltage control circuit, and controls the voltage applied to each power supply 131 according to an instruction from the control calculation unit 141 of the control display unit 14. Each power supply 131 and voltage control unit 132 may be configured as one circuit.

The transmission circuit 133 includes various circuits such as a trigger generation circuit, a delay circuit, and a pulsar circuit, and supplies a drive signal to the ultrasonic transformer 12.

The receiving circuit 134 is configured to include various circuits such as an amplifier circuit, an A / D converter, and an adder, and performs various processing on the reflected wave signal generated by the ultrasonic transducer 12 to perform various processing on the reflected wave. Generate data. Subsequently, the control display unit 14 will be described.

The control display unit 14 outputs various instructions including voltage control to the circuit 13 and drive instructions to the ultrasonic transformer 12, and outputs the reflected wave data obtained according to the drive instructions by a computer. It is composed. As shown in FIG. 1, the control display unit 14 includes a control calculation unit 141, an operation display unit 142, and a storage unit 143. The control display unit 14 and the circuit unit 13 may be built in one computer.

The control calculation unit 141 instructs the ultrasonic transformer 12 to control the transmission and reception of ultrasonic waves and the voltage control to the circuit unit 13, and also superimposes based on the reflected wave received by the ultrasonic transducer 12. It is a circuit that generates an ultrasonic image. Further, the control calculation unit 141 generates an ultrasonic image from the reflected wave data output from the reception circuit 134 of the circuit unit 13.

The control calculation unit 141 is a control processor that realizes a function as an information processing device (computer), and controls the entire processing of the display control unit 14 and the ultrasonic wave transmission / reception device 100. Specifically, the control calculation unit 141 is based on various setting requests input from the operator via the operation display unit 142, various control programs read from the storage unit 143, and various data, and is based on the circuit unit 13. Control the processing of. Further, the control calculation unit 141 displays various images such as ultrasonic images stored in the storage unit 143, a GUI (Graphical User Interface) for performing processing by the control calculation unit 141, processing results, and the like on the operation display unit 142. Perform display control.

The control calculation unit 141 is, for example, a CPU (central preprocess unit), a GPU (Graphics Processing Unit), an integrated circuit for a specific application (ASIC), or a programmable logic device (for example, a simple programmable logic device (Simple)). It is composed of circuits such as a Programmable Logic Device (SPLD), a Complex Programmable Logic Device (CPLD), and a Field Programmable Gate Array (FPGA). Instead of storing the program in the storage unit 143, the program may be directly incorporated in the circuit of the control calculation unit 141. In this case, the control calculation unit 141 realizes the function by reading and executing the program incorporated in the circuit.

The operation display unit 142 receives an operation from the operator of the ultrasonic wave transmission / reception device 100, displays a GUI for inputting various setting requests, and displays an ultrasonic image or the like generated by the control calculation unit 141. It has a display device. Further, the operation display unit 142 has an input device 3 including a track ball, a switch, a dial, a touch command screen, and the like.

The operation display unit 142 receives various setting requests for controlling the ultrasonic transducer 12 from the operator of the ultrasonic transmission / reception device 100, and outputs the received various setting requests to the control calculation unit 141.

The storage unit 143 is a memory for storing the ultrasonic image generated by the control calculation unit 141. The storage unit 143 is realized by, for example, a RAM (Random Access Memory), a semiconductor memory element such as a flash memory, a hard disk, an optical disk, or the like. Although not particularly described below, a program for performing ultrasonic wave transmission / reception, image processing, and display processing, diagnostic information (for example, patient ID, doctor's findings, etc.), diagnostic protocol, and various bodies are stored in the storage unit 143. -Various data such as marks may be stored.

FIG. 2 is a diagram showing a structural example of the ultrasonic transducer 12. As shown in FIG. 2, the ultrasonic transducer 12 is physically configured to include the matching layer 121, the piezoelectric element 122, the backing 123, and the cover 124. The backing 123 is provided to absorb the ultrasonic pulse radiated in the direction opposite to the ultrasonic irradiation direction when the ultrasonic pulse is transmitted by the piezoelectric element 122, and suppress the extra vibration of the piezoelectric element 122. It is a member. The cover-124 is a member that forms a storage space for the matching layer 121, the piezoelectric element 122, and the backing 123. FIG. 2 shows an example in which the matching layer 121 is composed of three matching layers from the first matching layer 121-1 to the third matching layer 121-3.

FIG. 3 is a diagram showing a structural example of the matching layer 121 shown in FIG. As shown in FIG. 3, the matching layer 121 is composed of a laminated structure formed by the first matching layer 121-1 forming the first layer and the Nth matching layer 121-n forming the Nth layer. In the following, a case where such a laminated structure is applied to the matching layer 121 is illustrated, but it may be configured by a single layer structure. Further, each layer of the matching layer 121 forming the laminated structure is configured to have one or a plurality of cells 31. In FIG. 3, for example, the first matching layer 121-1 formed as the first layer is composed of eight cells 31-1 and the Nth matching layer 121-n formed as the Nth layer is composed of two cells 31. It is shown that it is composed of −n. Although FIG. 3 shows an example in which each matching layer 121 is composed of a plurality of cells 31, it may be composed of one cell 31. That is, the number of cells 31 constituting each matching layer 121, the size of the cells 31, and the stacking order of the matching layers 121 are arbitrarily combined according to the usage environment of the ultrasonic transmission / reception device 100 and the medium such as the subject. Can be done.

Therefore, as illustrated in FIG. 3, it is not always necessary to increase the size of the cells 31 in order from the lower matching layer to make them different, and conversely, to decrease the size of the cells 31 in order from the upper matching layer. The cells 31 of each matching layer may have the same size, and may be combined as appropriate.

FIG. 4 is a diagram showing a structural example of the cell 31 shown in FIG. As shown in FIG. 4, the cell 31 has a flat upper surface plate 311 ((first member)) having an upper surface electrode 311a (first electrode) and a lower surface electrode 312a (second electrode). It is configured to have a flat plate-shaped lower surface plate 312 (second member) and a support member 313 that supports the upper surface plate 311 and the lower surface plate 312. That is, the cell 31 is composed of the upper surface plate 311 and the lower surface plate. The 312 and the support member 313 are configured to form a gap X.

Specifically, as will be described later, the inventors have made the cell 31 have a gap as described above, and by changing the size of the contact area between the upper surface plate 311 and the lower surface plate 312, the acoustic impedance We have realized a matching layer that makes it variable. Conventionally, an inorganic material is used for the matching layer, but in order to accurately match the acoustic impedance, the frequency band must be adjusted by changing the thickness and the number of layers of the matching layer according to the type of subject and the like. Therefore, it was difficult to adjust in a wide frequency band. In view of such conventional problems, the inventors have adopted a capacitance type cell having a gap to form a matching layer, and control the voltage applied to the cell to perform acoustic impedance. I came up with the idea of matching the dance.

The CMUT device is a device in which the electrostatic force generated by the voltage applied to the two electrodes vibrates the upper surface plate or the lower surface plate due to the attractive force pulling the two electrodes, and the capacitance between the electrodes changes. Therefore, normally, the voltage is controlled so as to generate sound waves by vibrating the upper surface plate having the electrodes and the lower surface plate instead of bringing them into contact with each other. However, the present inventors have focused on the structure of such a CMUT device, and, contrary to such a conventional control method, suppress vibration by bringing the upper surface plate having an electrode and the lower surface plate into contact with each other. We have come to adopt a method of matching the acoustic impedance by suppressing the reflection of sound waves as much as possible. Hereinafter, the structure of the cell 31 and the control of the cell 31 in this embodiment will be described.

In this embodiment, the case where the CMUT device is applied to the cell 31 is described, but the same can be considered when the PMUT (Piezoelectric Micromachined Ultrasonic Transducers) device is applied to the cell 31.

FIG. 5A is a diagram showing a structural example of the cell 31 during voltage control. As shown in FIG. 5A, when a voltage is applied to the upper surface electrode 311a of the upper surface plate 311 by the power supply 131 of the circuit unit 13, the upper surface of the cell 31 is bent toward the gap X side and deformed to come into contact with the lower surface. do. At this time, the gap X is divided into two gaps X1 by the bottom plate 312, the top plate 311 in contact with the bottom plate 312, and the support member 313. As the applied voltage increases, the contact area C gradually increases as shown in the graph shown in FIG. 5B. Although FIG. 5A shows an example in which a voltage is applied to the upper surface plate 311, the same can be considered when a voltage is applied to the lower surface plate 312. By controlling the magnitude of the applied voltage to the cell 31 in this way, the magnitude of the contact area C can be increased or decreased, and the acoustic impedance can be changed without changing the structure of the matching layer. The extent to which the size of the contact area C is controlled may be appropriately determined according to the usage environment of the ultrasonic transmission / reception device 100 and the medium such as the subject.

FIG. 6 is a diagram showing another structural example of the cell 31 shown in FIG. In FIG. 6, a plurality of protrusions P protruding toward the gap X side, which is the inner surface side of the lower surface plate 312, are provided in a staircase pattern. The protrusions P are provided on the lower surface plate 312 at equal intervals so that the height gradually increases as the distance from the center of the gap X toward the support member 313 increases. Although FIG. 6 shows an example in which the protrusions P are provided on the lower surface plate 312, each protrusion P may be provided on the upper surface plate 311.

Further, in FIG. 6, a plurality of protrusions P are arranged in a staircase pattern as described above, but the height of each protrusion P may be the same. Further, the protrusions P do not necessarily have to be arranged at equal intervals, and the width between certain protrusions and the width between other protrusions may be changed. Further, the width of each protrusion P in the support member 313 direction does not necessarily have to be the same width, and the width of one protrusion P and the width of another protrusion P may be different from each other. Further, the contact surface between each protrusion P and the upper surface plate 311 or the lower surface plate 312 when a voltage is applied does not have to be flat, and may have other shapes. That is, the protrusion P may be arranged so that the upper surface plate 311 or the lower surface plate 312 can be contacted in multiple stages as described later in a three-dimensional shape when a voltage is applied.

FIG. 7A is a diagram showing another structural example of the cell 31 during voltage control. As shown in FIG. 7A, when a voltage is applied to the upper surface electrode 311a of the upper surface plate 311 by the power supply 131 of the circuit unit 13, the upper surface plate 311 is bent toward the gap X side and deformed to protrude. Contact P. FIG. 7A shows an example in which the top plate 311 is in contact with all the protrusions P (P1 to P7). In this case, the gap X is divided into eight gaps X2 by the protrusion P, the upper surface plate 311 in contact with the protrusion P, the lower surface plate 312, and the support member 313. In the example shown in FIG. 7A, the larger the applied voltage, the larger the number of protrusions P with which the top plate 311 comes into contact. Specifically, as the applied voltage increases, the top plate 311 has two protrusions P1 and P7 → four protrusions P1, 2 and P6, 7 → protrusions P1, 2, 3 and P5, 6 protrusions of 6 and 7 → By contacting all 7 protrusions from protrusions P1 to P7 in this order, the number of protrusions in contact changes, and the contact area C becomes as shown in the graph shown in FIG. 7B. It grows gradually.

In this way, by controlling the magnitude of the applied voltage to the cell 31, the number of protrusions P that the top plate 311 contacts is changed, and the magnitude of the contact area C is increased or decreased stepwise. Therefore, as compared with the case of FIG. 5A, the change in acoustic impedance can be easily adjusted.

FIG. 8 is a diagram showing an example of an applied voltage control table that defines a method for controlling the applied voltage. Although the table will be described as being stored in the storage unit 143 in advance, it may be stored in the control calculation unit 141 or the voltage control unit 132. As shown in FIG. 8, the applied voltage control table 1431 stores each layer constituting the matching layer and a voltage value determined for each propagation medium as a subject in association with each other.

In FIG. 8, for example, in the first matching layer 121-1 which is the first matching layer, the value of the applied voltage is set to (A) when the subject is the propagation medium 1, and the subject propagates. It shows that the value of the applied voltage is set to (E) when the medium is 2, and the value of the applied voltage is set to (I) when the subject is the propagation medium 3. Similarly, the value of the applied voltage is set for each propagation medium for the matching layer of each of the other layers. In this way, by determining the applied voltage according to the type of the subject for each layer constituting the matching layer, one ultrasonic transformer 12 is used to ultrasonic waves for various types of subjects. Can be sent and received. The value of the applied voltage defined by the applied voltage control table 1431 shown in FIG. 8 is, for example, read from the applied voltage control table 1431 stored in the storage unit 143 by the control calculation unit 141 and displayed on the operation display unit 142. The display is set by the operation display unit 142 receiving the selection of the applied voltage value for each matching layer and each propagation medium from the operator. Although the value of the applied voltage is determined for each layer of the matching layer and for each propagation medium in FIG. 8, the value of the applied voltage may be determined for each cell 31 constituting each of the above layers and for each propagation medium.

As described above, in this embodiment, a gap is provided in the cell 31 constituting the matching layer 121, and for example, a voltage is applied to the electrodes of the upper surface plate 131 and the lower surface plate 132 in which the cell 31 sandwiches the gap. The upper surface plate 131 and the lower surface plate 132 of at least one cell 31 are in contact with each other, and the contact area between the upper surface plate 131 and the lower surface plate 132 can be changed by controlling the magnitude of the applied voltage according to the medium such as the subject. The configuration is adopted. Therefore, the acoustic impedance can be easily changed according to various subjects without changing the structure of the ultrasonic transducer 12, and the ultrasonic transducer 12 can be miniaturized. Can be done.

FIG. 1 illustrates a case where a power supply 131 is provided for each matching layer 121. However, when further miniaturization of the ultrasonic transformer 12 is required, for example, as shown in FIG. 9, one power supply 131A provided in the circuit unit 13A of the ultrasonic transmitter / receiver 200 is super-powered. A voltage may be applied to each matching layer 121 of the ultrasonic transformer 12. In this case, since the same voltage is applied to each matching layer from the power supply 131A, for example, when the matching layer 121 changes the size of the cell 31 of each layer as shown in FIG. 3, the voltage is applied. The cell 31 that reacts differs depending on the magnitude of the voltage.

Therefore, the size of the contact area can be made variable for each layer of the matching layer 121 and for each cell. Of course, in the configuration shown in FIG. 1, the same case can be considered when each power supply 131 applies a voltage of the same magnitude to each corresponding matching layer 121.

FIG. 10 is a diagram showing a configuration example of an ultrasonic wave transmission / reception device 300 provided with a power supply 131 for each cell 31. As shown in FIG. 10, the circuit unit 13B of the ultrasonic transmission / reception device 300 is configured to provide a power supply 131B for each cell 31 constituting the matching layer 121 and control the magnitude of the voltage applied to each cell 31 unit. There is. FIG. 10 illustrates a configuration in which a power supply 131B is provided corresponding to each of a plurality of cells 31 (cells A to M) constituting the first matching layer 121-1. With such a configuration, the applied voltage can be controlled on a cell-by-cell basis, so that the acoustic impedance can be changed more finely. Although the configuration of the first matching layer 121-1 is illustrated in FIG. 10, a power supply may be provided for each cell 31 for all the layers constituting the matching layer 121, or a part of the matching layer 121. A power source may be provided for each cell 31.

That is, among the layers constituting the matching layer 121, a layer in which the applied voltage is controlled in the cell unit and a layer in which the applied voltage is controlled in the layer unit may be combined. Such a combination can be determined according to the usage environment of the ultrasonic transmission / reception device and a medium such as a subject.

FIG. 11 is a diagram showing a configuration example of an ultrasonic transmitter / receiver 400 that analyzes the reflected wave signal received from the ultrasonic transducer 12 and feeds back the analysis result to the voltage control unit 132. As shown in FIG. 11, the control display unit 14 of the ultrasonic transmission / reception device 400 has a control calculation unit 141A, and the control calculation unit 141A is provided with a feedback circuit 1411 and a signal processing unit 1412. ing.

The feedback circuit 1411 controls the magnitude of the applied voltage based on the value of the reflected wave signal received from the signal processing unit 1412 and the optimum value of the reflected wave signal, and outputs the result of the control to the circuit unit 13. It is output to the voltage control unit 132 of the above and fed back. For example, the feedback circuit 1411 instructs the voltage control unit 132 to change the contact area of the cell by applying a voltage large enough to pass through the bone of the human body when the subject is a bone of the human body. do. Further, for example, when the value of the reflected wave signal is less than the optimum value, the feedback circuit 1411 instructs the voltage control unit 132 to increase the applied voltage to increase the contact area of the cell.

When the signal processing unit 1412 receives the reflected wave data based on the reflected wave signal received from the receiving circuit 134 of the circuit unit 13, the value of the reflected wave signal included in the reflected wave data and each subject. The optimum value of the determined reflected signal is output to the feedback circuit 1411. The optimum value of the reflected signal may be stored in advance in the storage unit 143, the control calculation unit 141, and the voltage control unit 132. Although FIG. 11 shows an example in which the feedback circuit 1411 and the signal processing unit 1412 are applied to the ultrasonic wave transmission / reception device 100 shown in FIG. 1, the ultrasonic wave transmission / reception device 200 and FIG. 10 shown in FIG. 9 show. The same can be applied to the ultrasonic transmission / reception device 300 shown in the above.

It should be noted that the present embodiment is not limited to the present embodiment, and at the implementation stage, the components may be modified and embodied within a range that does not deviate from the gist thereof, or a plurality of components disclosed in the above embodiment may be appropriately used. It can be carried out in combination. For example, the matching layer 121 composed of the cell 31 having the protrusion P shown in FIG. 6 can be applied to the ultrasonic transmission / reception device shown in FIGS. 9 and 10, or the applied voltage control test shown in FIG. 8 can be applied. The bull may be applied to the ultrasonic transmitter / receiver shown in FIGS. 9 and 10.

100, 200, 300, 400 Ultrasonic transmitter / receiver 12 Ultrasonic transformer 121 Matching layer 122 Piezoelectric element 13, 13A, 13B Circuit unit 131, 131A, 131B Power supply 132 Voltage control unit 133 Transmission circuit 134 Reception circuit 14 Control display Units 141, 141A Control calculation unit 1411 Piezoelectric circuit 1412 Signal processing unit 142 Operation display unit 143 Storage unit 1431 Applied voltage control table 31 Cell X, X1, X2 Void P, P1 to P7 Protrusions

Claims (9)

A gap was formed by the first member having the first electrode, the second member having the second electrode, and the support member supporting the first member and the second member. A matching layer with cells and
A control unit that controls the applied voltage to change the area of contact between the first member and the second member.
An ultrasonic transmitter / receiver characterized by being equipped with. The matching layer is configured to have a plurality of the cells having different sizes.
The ultrasonic wave transmission / reception device according to claim 1. The cell is provided with a plurality of protrusions protruding into the gap, and the cell is provided with a plurality of protrusions.
The control unit changes the contact area by controlling the applied voltage and changing the number of contacts of the first member or the second member with the protrusions.
The ultrasonic wave transmission / reception device according to claim 1. The control unit controls the applied voltage according to the type of the subject and changes the contact area.
The ultrasonic wave transmission / reception device according to claim 1. The matching layer is composed of a laminated structure composed of a plurality of matching layers.
The control unit controls the voltage applied by the power supply provided for each matching layer and changes the contact area.
The ultrasonic wave transmission / reception device according to claim 1. The matching layer is composed of a laminated structure composed of a plurality of matching layers.
The control unit controls the voltage applied by one power supply provided for the plurality of matching layers, and changes the contact area.
The ultrasonic wave transmission / reception device according to claim 1. The matching layer is configured to have a plurality of the cells.
The control unit controls the voltage applied by the power supply provided for each of the plurality of cells, and changes the contact area.
The ultrasonic wave transmission / reception device according to claim 1. The control unit includes a feedback circuit that feeds back a voltage to be applied based on a reflected wave signal received from the matching layer.
The ultrasonic wave transmission / reception device according to claim 1. A gap was formed by the first member having the first electrode, the second member having the second electrode, and the support member supporting the first member and the second member. A matching layer having a cell and changing the contact area between the first member and the second member based on an applied voltage controlled by a control unit.
A piezoelectric element that radiates ultrasonic waves according to instructions from the control unit and outputs a reflected wave signal based on the reflected wave received from the subject to the control unit.
An ultrasonic transducer characterized in that it comprises.

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