JP5893502B2 - Ultrasonic observation apparatus and method of operating ultrasonic observation apparatus - Google Patents

Description

The present invention relates to an ultrasonic observation apparatus in which an electronic scanning ultrasonic unit in which a plurality of capacitive ultrasonic elements are arranged is connected to an ultrasonic endoscope disposed at a distal end portion of an insertion portion. And an operation method of the ultrasonic observation apparatus .

  An ultrasonic diagnostic method is widely used in which a generated ultrasonic wave is irradiated into a body and a reflected wave is received to image and diagnose a state inside the body. For example, an ultrasonic endoscope system includes an ultrasonic endoscope and an ultrasonic observation apparatus. In the ultrasonic endoscope, an ultrasonic unit (hereinafter also referred to as “US unit”) that transmits and receives ultrasonic waves is disposed at a distal end portion of an insertion portion introduced into the body. The ultrasonic vibrator of the US unit has a function of converting an electric signal (transmission signal) into an ultrasonic wave, and receiving an ultrasonic wave reflected in the body and converting it into an electric signal (reception signal).

  For the ultrasonic vibrator, a ceramic piezoelectric material containing lead that may have a large environmental load, such as PZT (lead zirconate titanate), is mainly used. On the other hand, a capacitive ultrasonic transducer (Capacitive Micro-machined Ultrasonic Transducer; hereinafter referred to as “c-MUT”) manufactured using MEMS (Micro Electro Mechanical Systems) technology does not contain lead. ) Is under development.

  The c-MUT has as its basic element an ultrasonic cell (hereinafter also referred to as “US cell”) in which an upper electrode and a lower electrode are arranged to face each other via a cavity (cavity). In the US cell, the membrane including the upper electrode on the upper side of the cavity constitutes the vibrating part. A plurality of US cells in which the upper electrode / lower electrode are connected to each other by the wiring portion constitute an ultrasonic element (hereinafter also referred to as “US element”) which is a basic unit of transmission and reception.

  In the US cell, by applying a voltage between the lower electrode and the upper electrode, the membrane including the upper electrode is vibrated by an electrostatic force to generate ultrasonic waves. In addition, when an ultrasonic wave is incident on the membrane from the outside, the distance between both electrodes changes, so that the ultrasonic wave is converted into an electric signal from the change in capacitance.

  US Pat. No. 6,795,374 discloses a control method in which different DC bias voltages are applied to a c-MUT type ultrasonic element at the time of transmission and at the time of reception in order to improve transmission / reception efficiency.

  However, in the above control method, since transmission / reception is performed by one US cell, it is necessary to quickly change the DC bias voltage from transmission to reception after transmission. Then, the membrane vibrates and unnecessary ultrasonic waves are generated or noise is generated in the received signal. In addition, crosstalk occurs between adjacent US elements. For this reason, in an ultrasonic observation apparatus that applies different DC bias voltages at the time of transmission and at the time of reception, there is a possibility that it is not easy to acquire a clear image.

  On the other hand, Japanese translations of PCT publication No. 2005-510264 (US Pat. No. 6,585,653) discloses a c-MUT having a US cell dedicated for transmission and a US cell dedicated for reception.

  In a US unit having a US element in which a US cell is divided into a transmission-only and a reception-only, there is no need to switch the DC bias voltage. However, the density of ultrasonic waves to be transmitted and received is half that of a normal US element. Further, crosstalk occurs depending on the arrangement of the transmission dedicated cell and the reception dedicated cell. For this reason, there is a possibility that it is not easy to obtain a clear image.

US Pat. No. 6,795,374 JP 2005-510264 A (US Pat. No. 6,585,653)

An embodiment of the present invention aims to provide an ultrasonic observation apparatus and an operation method of the ultrasonic observation apparatus that can acquire a clear image.

In the ultrasonic observation apparatus according to the embodiment of the present invention, an ultrasonic unit in which a plurality of capacitive ultrasonic elements are arranged is connected to an ultrasonic endoscope arranged in the distal end portion of the insertion portion. An ultrasonic observation apparatus, a transmission unit that generates a transmission signal converted into an ultrasonic wave transmitted from a transmission element that is at least one of the plurality of ultrasonic elements, and a transmission from the transmission element A reception unit that processes a reception signal obtained by converting the reflected wave of ultrasonic waves converted into an electrical signal, and the reflected wave of ultrasonic waves transmitted from the transmission element is not received by the transmission element; A transmission / reception switching unit that switches between the transmission unit and the ultrasonic element connected to the reception unit so that the reception element is another ultrasonic element arranged close to the element. A transmission bias control unit that applies a transmission DC bias voltage to the transmission element; and a reception DC bias voltage that is different from the transmission DC bias voltage to the reception element. A plurality of ultrasonic cells in which the upper electrode is arranged opposite to the lower electrode through the cavity, and the width W length is provided in the ultrasonic element. The rectangular elements having a length L (W <L) are arranged at a predetermined interval D that is at least twice the diameter R of the cavity of the ultrasonic cell so that the longitudinal directions thereof are adjacent to each other .
An ultrasonic observation apparatus according to another embodiment includes an ultrasonic unit in which an ultrasonic unit in which a plurality of capacitive ultrasonic elements are arranged is connected to an ultrasonic endoscope arranged in a distal end portion of an insertion unit. An ultrasonic observation apparatus, wherein a transmission unit that generates a transmission signal converted into an ultrasonic wave to transmit ultrasonic waves from the ultrasonic element, and an ultrasonic wave to receive ultrasonic waves at the ultrasonic element A reception unit that processes the reception signal converted from the transmission unit, a transmission bias control unit that is provided in the transmission unit and applies a DC bias voltage for transmission to an ultrasonic element connected to the transmission unit, and the reception A reception bias control unit that applies a reception DC bias voltage different from the transmission DC bias voltage to the ultrasonic element connected to the reception unit, and is connected to the ultrasonic element. The transmission bias controller generates the transmission bias voltage and transmits the transmission signal to transmit the transmission signal, and the reception bias controller generates the ultrasonic element. A transmission / reception switching unit that switches between a state in which the reception DC bias voltage is applied and the reception unit is connected so as to receive a reception signal, and the upper electrode is connected to the ultrasonic element via a cavity. A plurality of ultrasonic cells arranged opposite to the lower electrode are arranged in a matrix,
The rectangular elements having a width W and a length L (W <L) are arranged at a predetermined interval D that is at least twice as large as the diameter R of the cavity of the ultrasonic cell so that their longitudinal directions are adjacent to each other. It is .
In addition, an operation method of the ultrasonic observation apparatus according to another embodiment is an ultrasonic observation apparatus in which an ultrasonic unit in which a plurality of capacitance-type ultrasonic elements are arranged is arranged at the distal end portion of the insertion portion. In the operating method, the transmission / reception switching unit transmits the transmission element, which is at least one of the plurality of ultrasonic elements, from the transmission bias control unit that applies a DC bias voltage for transmission and the transmission element. A transmitting unit that generates a transmission signal to be converted into ultrasonic waves, and after connection, the transmission / reception switching unit is a receiving element that is another ultrasonic element disposed close to the transmitting element, A reflected bias wave of the ultrasonic wave transmitted from the reception bias control unit for applying the reception DC bias voltage and the transmission element, which is different from the transmission DC bias voltage. A receiver for processing the received signals converted into electrical signal, connected, the ultrasonic element, a plurality of ultrasonic cell where the upper electrode is disposed facing the lower electrode through the cavity are arranged in a matrix And
The rectangular elements having a width W and a length L (W <L) are arranged at a predetermined interval D that is at least twice as large as the diameter R of the cavity of the ultrasonic cell so that their longitudinal directions are adjacent to each other. It is .

According to the embodiment of the present invention, it is possible to provide an ultrasonic observation apparatus capable of acquiring a clear image and an operation method of the ultrasonic observation apparatus .

1 is an external view of an endoscope system including an ultrasonic observation apparatus according to an embodiment. It is an external view of the front-end | tip part of the ultrasonic endoscope connected with the ultrasonic observation apparatus of embodiment. It is an external view of the US unit connected to the ultrasonic observation apparatus of the embodiment. It is an external view of the US element connected to the ultrasonic observation apparatus of the embodiment. 1 is a configuration diagram of an endoscope system including an ultrasonic observation apparatus according to an embodiment. It is a figure for demonstrating operation | movement of the ultrasonic observation apparatus of embodiment. It is a figure for demonstrating the signal of the ultrasonic observation apparatus of embodiment. It is a figure for demonstrating operation | movement of the ultrasonic observation apparatus of a modification. It is a figure for demonstrating operation | movement of the ultrasonic observation apparatus of a modification. It is a figure for demonstrating operation | movement of the ultrasonic observation apparatus of a modification. It is a structure diagram of the US unit of the modification connected with an ultrasonic observation apparatus. It is a structure diagram of the US unit of the modification connected with an ultrasonic observation apparatus.

Hereinafter, the ultrasonic observation apparatus 3 according to the embodiment will be described with reference to the drawings.
<Configuration of ultrasonic endoscope>
As shown in FIG. 1, the ultrasonic observation apparatus 3 constitutes an ultrasonic endoscope system 1 together with the ultrasonic endoscope 2 and the monitor 4. The ultrasonic endoscope 2 includes an elongated insertion portion 11 to be inserted into the body, an operation portion 12 disposed at the proximal end of the insertion portion 11, a universal cord 13 extending from a side portion of the operation portion 12, It comprises.

  A connector 14 </ b> A connected to a light source device (not shown) is disposed at the base end of the universal cord 13. From the connector 14A, a cable 15 is detachably connected to a camera control unit (not shown) via a connector 15A, and a cable 16 is detachably connected to the ultrasonic observation apparatus 3 via a connector 16A. It is extended. A monitor 4 is connected to the ultrasonic observation apparatus 3.

  The insertion portion 11 is, in order from the distal end side, a distal end portion 17, a bending portion 18 located at the rear end of the distal end portion 17, and a small diameter and long length that is located at the rear end of the bending portion 18 and reaches the operation portion 12. A flexible tube portion 19 having flexibility is provided in series. An ultrasonic unit (US unit) 30 that is an ultrasonic transmission / reception unit is disposed on the distal end side of the distal end portion 17.

  The operation unit 12 includes an angle knob 12A for controlling the bending portion 18 to bend in a desired direction, an air / water supply button 12B for performing air supply and water supply operations, a suction button 12C for performing suction operations, and a treatment introduced into the body. A treatment instrument insertion port 12D and the like serving as an entrance of the instrument are disposed.

  Then, as shown in FIG. 2, the US unit 30 for transmitting and receiving ultrasonic waves is provided at the tip 17 provided with an illumination lens cover 31 constituting an illumination optical system and an observation lens cover 32 of the observation optical system. A forceps port 33 that also serves as a suction port and an air / water supply nozzle (not shown) are provided.

<Configuration of ultrasonic unit>
Next, the configuration of the ultrasonic unit 30 will be described with reference to FIGS. 3, 4, and 5.

  As shown in FIG. 3, the ultrasonic unit 30 includes a plurality of ultrasonic elements 60 having a substantially rectangular shape in plan view, a holding member 20 in which the plurality of ultrasonic elements 60 are joined to the outer peripheral surface, and the respective ultrasonic elements 60. And a cable 80 that is connected to the conductors 81A and 81B and transmits a signal. In the US unit 30, for example, about 200 US elements 60 having a short side of 0.1 mm or less are arranged on the outer peripheral surface of a cylinder having a diameter of 2 mm so that the long sides are adjacent to each other.

  As will be described later, in the ultrasonic unit 30, each ultrasonic element 60 does not receive an ultrasonic reflected wave generated by itself, but receives an ultrasonic reflected wave generated by another ultrasonic element 60. To be controlled.

  As shown in FIG. 4, the ultrasonic element 60 that is a basic unit for transmitting and receiving ultrasonic waves has a first main surface 60SA and a second main surface 60SB facing the first main surface 60SA. A transmitter / receiver 61 for transmitting and receiving ultrasonic waves is formed at a substantially central portion of the first main surface 60SA of the ultrasonic element 60, and external electrodes 62A and 62B are provided at both ends of the first main surface 60SA. It is arranged. As shown in FIG. 3, the external electrodes 62A and 62B are connected to the conducting wires 81A and 81B of the cable 80, respectively. The external electrodes 62A and 62B are connected to the transmission / reception switching unit 21 of the ultrasonic observation apparatus 3 via the cable 80.

  In the transmission / reception unit 61, a plurality of capacitive ultrasonic cells 10 are arranged in a matrix. FIG. 4 schematically shows only a part of the ultrasonic cells 10. In the ultrasonic cell 10, the upper electrode constituting the membrane is disposed to face the lower electrode via a cavity (gap). The external electrode 62 </ b> A is a common electrode for the lower electrodes of the plurality of ultrasonic cells 10, and the external electrode 62 </ b> B is a common electrode for the upper electrodes of the plurality of ultrasonic cells 10.

  On the other hand, as illustrated in FIG. 5, the ultrasound observation apparatus 3 includes a transmission / reception switching unit 21, a bias control unit 22, a reception unit 23, a transmission unit 24, and a control unit 25. As will be described later, the transmission / reception switching unit 21 connects the ultrasonic element 60 selected from the plurality of ultrasonic elements 60 of the ultrasonic unit 30 and the transmission unit 24 or the reception unit 23.

  The bias control unit 22 includes a transmission bias control unit 22A and a reception bias control unit 22B, and applies different DC bias voltages to the transmission element and the reception element. Note that the transmission bias control unit 22A and the reception bias control unit 22B may have one bias control unit having two functions with a time difference.

  The reception unit 23 includes an amplification unit 23A, an AD conversion unit 23B, a reception beamformer generation unit 23C, and a signal processing unit 23D. On the monitor 4, an ultrasonic image signal-processed by the receiving unit 23 is displayed. The transmission unit 24 includes a delay circuit 24A and a transmission waveform generation unit 24B. The control unit 25 may perform not only control of the ultrasound observation apparatus 3 but also overall control of the ultrasound endoscope system 1.

  As shown in FIG. 3, the US unit 30 is a radial electronic scanning type unit that scans a range of 360 degrees using a plurality of ultrasonic elements 60 arranged in a circle. That is, the transmission / reception switching unit 21 scans a range of 360 degrees by sequentially switching the ultrasonic elements connected to the transmission unit 24 or the reception unit 23 in the circumferential direction.

  The US unit 30 may be a convex electronic scanning unit that scans a predetermined angle range by using a plurality of ultrasonic elements 60 arranged in a convex curved surface.

  The ultrasonic observation apparatus 3 performs scanning with a predetermined distance as a focal point by a plurality of ultrasonic beams. That is, an ultrasonic beam (sound ray) transmitted in a desired direction is synthesized by sequentially driving a plurality of adjacent US elements with a delay time. For example, 2 to 36 US elements are used for sound ray synthesis. A combined ultrasonic beam is formed by transmitting the ultrasonic beam simultaneously or substantially simultaneously using a plurality of US elements arranged at different positions. Further, the inside of the subject is radially scanned while changing the direction of the ultrasonic beam according to the transmission timing.

  The transmission waveform signal generated by the transmission waveform generation unit 24B of the transmission unit 24 is delayed by the delay circuit 24A to synthesize a sound ray. The transmission waveform signal to which a predetermined transmission bias voltage is applied by the transmission bias control unit 22A is applied to the transmission US element selected by the transmission / reception switching unit 21.

  On the other hand, a predetermined reception bias voltage is applied to the reception US element selected by the transmission / reception switching unit 21 by the reception bias control unit 22B. In order to improve reception sensitivity, the reception bias voltage is set higher than the transmission bias voltage. The reception signal is amplified by the amplification unit 23A of the reception unit 23 and converted into a digital signal by the AD conversion unit 23B. The reception beamformer generation unit 23C generates a composite signal based on the reception signals of the plurality of ultrasonic elements 60, and the signal processing unit 23D processes the composite signal to create an ultrasonic image.

  Next, the operation of the ultrasound observation apparatus 3 will be described in detail with reference to FIGS. 6 (A) to 6 (C). Here, for the sake of simplicity of explanation, a single beam in which one other US element receives an ultrasonic reflected wave transmitted from one US element will be described. By continuously transmitting and receiving single beams (sound rays) having different phases, a synthesized sound ray having a focal point at a predetermined position is formed.

  In the state of FIG. 6 (A), the N-th US element 60N is connected to the transmission unit 24 in the transmission / reception switching unit 21 under the control of the control unit 25, and the reception unit 23 is connected to the (N + 1) th US element 60 (N + 1). Is connected. Therefore, the reflected ultrasonic wave generated by the Nth US element 60N is not received by the Nth US element 60N, but is received by the (N + 1) th US element 60 (N + 1).

  Here, the transmission / reception switching unit 21 and the like are controlled by a control signal from the control unit 25. For example, as illustrated in FIG. 7, the control unit 25 transmits a state transition signal so that the transmission / reception switching unit 21 is in the state A illustrated in FIG. 6A based on the sound ray trigger signal (sound ray TRG). To do. In the state (A), the Nth US element 60N is a transmission element, and the (N + 1) th US element 60 (N + 1) is a reception element. Then, the transmission signal generated by the transmission unit 24 by the transmission trigger signal (transmission TRG) from the control unit 25 is transmitted to the Nth US element 60N.

  In response to the reception trigger signal (reception TRG) from the control unit 25, the reception unit 23 receives a signal (echo signal) based on the reflected wave. The ultrasonic waves generated by the Nth US element 60N are reflected in the body, and the reflected waves return to the US unit 30. Vibration due to the reflected wave also occurs in the Nth US element 60N. However, since the Nth US element 60N is not connected to the receiving unit 23, the received signal is not received. On the other hand, the (N + 1) -th US element 60 (N + 1) connected to the receiving unit 23 receives the vibration due to the reflected wave as a reception signal, and data for one sound ray is acquired.

  The transmission / reception switching unit 21 that has completed the transmission / reception in the state of FIG. 6A and has received the state transition signal is then in the state of FIG. 6 (B). 6B, in the transmission / reception switching unit 21, the (N + 1) th US element 60 (N + 1) is connected to the transmission unit 24, and the reception unit 23 is connected to the (N + 2) th US element 60 (N + 2). Has been. Therefore, the reflected wave of the ultrasonic wave generated by the (N + 1) th US element 60 (N + 1) is not received by the (N + 1) th US element 60 (N + 1), and the (N + 2) th US element 60 (N + 2). ).

  The transmission / reception switching unit 21 that has completed the transmission / reception in the state of FIG. 6 (B) and has received the state transition signal then enters the state of FIG. 6 (C). 6C, in the transmission / reception switching unit 21, the (N + 2) th US element 60 (N + 2) is connected to the transmission unit 24, and the reception unit 23 is connected to the (N + 3) th US element 60 (N + 3). Has been. Therefore, the reflected wave of the ultrasonic wave generated by the (N + 2) th US element 60 (N + 2) is not received by the (N + 2) th US element 60 (N + 2), and the (N + 3) th US element 60 (N + 3) is not received. ).

  That is, the transmission / reception switching unit 21 switches the ultrasonic element connected to the transmission unit 24 or the reception unit 23 so that another ultrasonic element arranged adjacent to the ultrasonic element that transmitted the ultrasonic wave receives the ultrasonic element. .

  Then, each of the plurality of US elements arranged in a circle on the circumference sequentially becomes one transmission element or reception element, so that the scan of 360 degrees is completed, and one radial ultrasonic image is obtained. Created. The ultrasonic image is updated by continuously performing scanning.

Since the transmission element 60N and the reception element 60 (N + 1) are different elements, there is no need to change the DC bias voltage immediately after transmission, and the transmission signal does not adversely affect the reception signal. Further, the density of ultrasonic waves to be transmitted / received is the same as that of a normal US element. For this reason, the operating method of the ultrasonic observation apparatus 3 and the ultrasonic endoscope 2 can acquire a clear image.

<Modification of operation of ultrasonic observation apparatus 3>
The operation of the transmission / reception switching unit 21 of the ultrasonic observation apparatus 3 is not limited to the operation described with reference to FIGS. 6A to 6C, and may be the operation of the following modification.

  In the modification shown in FIGS. 8A to 8C, a plurality of ultrasonic elements are simultaneously connected to the transmission unit 24 or the reception unit 23. In the state shown in FIG. 8A, the ultrasonic elements 60K and 60 (K + 3) are receiving elements, and the ultrasonic elements 60 (K + 1) and 60 (K + 2) are transmitting elements. When transmission / reception in the state shown in FIG. 8A is completed, the state shown in FIG. In the state shown in FIG. 8B, the ultrasonic elements 60 (K + 1) and 60 (K + 4) are receiving elements, and the ultrasonic elements 60 (K + 2) and 60 (K + 3) are transmitting elements. In the state shown in FIG. 8C, the ultrasonic elements 60 (K + 2) and 60 (K + 5) are receiving elements, and the ultrasonic elements 60 (K + 3) and 60 (K + 4) are transmitting elements.

  The ultrasonic observation apparatus 3 according to the modification has a strong transmitted ultrasonic wave and a strong received signal. For this reason, a clearer image can be acquired.

  Further, in the modification shown in FIGS. 9A to 9C, a plurality of ultrasonic elements are connected to the transmitter 24 at the same time. In the state shown in FIG. 9A, the ultrasonic element 60 (K + 1) is a receiving element, and the ultrasonic elements 60 (K) and 60 (K + 1) are transmitting elements. When transmission / reception in the state shown in FIG. 9A is completed, the state shown in FIG. In the state shown in FIG. 9B, the ultrasonic element 60 (K + 2) is a receiving element, and the ultrasonic elements 60 (K + 1) and 60 (K + 3) are transmitting elements. In the state shown in FIG. 8C, the ultrasonic element 60 (K + 3) is a receiving element, and the ultrasonic elements 60 (K + 2) and 60 (K + 4) are transmitting elements.

  The ultrasonic observation apparatus 3 according to the modification has a strong reception signal. For this reason, a clearer image can be acquired.

  In the state shown in FIG. 10A of the modification shown in FIGS. 10A to 10C, the ultrasonic element 60K is a receiving element, and the ultrasonic element 60 (K + 1) is a transmitting element. It is. Then, when transmission / reception in the state shown in FIG. 10A is completed, the state shown in FIG. In the state shown in FIG. 10B, the ultrasonic element 60 (K + 2) is a receiving element, and the ultrasonic element 60 (K + 3) is a transmitting element. In the next scan in which all the ultrasonic elements 60 transmit or receive, as shown in FIG. 10C, the ultrasonic element 60 (K + 1) is a receiving element, and the ultrasonic element 60 (K + 2). ) Is a transmitting element.

  The ultrasonic observation apparatus 3 according to the modified example can acquire a clearer image because the sound ray density is low but is not easily affected by crosstalk.

  That is, the transmission / reception switching unit 21 does not receive the reflected ultrasonic wave transmitted from at least one of the plurality of ultrasonic elements, but does not receive the ultrasonic wave transmitted from the ultrasonic wave element. By switching the ultrasonic element connected to the transmission unit 24 or the reception unit 23 so as to be received by another ultrasonic element arranged close to the acoustic wave element, the ultrasonic observation apparatus 3 can display a clear image. You can get it.

<Modification of US unit>
As shown in FIG. 11A, in the US unit 30 of the embodiment, rectangular US elements 60 having a width W and a length L are arranged with a predetermined interval D so that their longitudinal directions are adjacent to each other. Yes. Here, the distance D is preferably at least twice the diameter R of the cavity of the US cell 10 in order to reduce crosstalk.

  Moreover, by forming the groove 34 between the US elements 60 as in the modified US unit 30B shown in FIG. 11B, crosstalk can be more effectively reduced. That is, the groove 34 is a crosstalk reducing means.

  Further, the US element may be composed of a first transmission / reception unit 61A and a second transmission / reception unit 61B that can be driven separately, even if they are one in appearance. In this case, as in the US unit 30C of the modified example shown in FIG. 11C, an area 61C composed of an undriven US cell is provided between the first transmitting / receiving unit 61A and the second transmitting / receiving unit 61B. It is preferable to reduce the crosstalk. That is, the region 61C is a crosstalk reducing means, and preferably has a width that is at least twice the diameter R of the cavity of the US cell 10.

  Furthermore, like US unit 30D shown in FIG. 12, US element 60D may be a square having the same width W and length L. A US unit having a square US element 60D has a higher sound ray density than that of a US unit having a rectangular US element, and a clearer image can be acquired.

  The present invention is not limited to the above-described embodiment or modification, and various changes, modifications, combinations, and the like are possible without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Ultrasound endoscope system, 2 ... Ultrasound endoscope, 3 ... Ultrasonic observation apparatus, 10 ... Ultrasonic cell, 11 ... Insertion part, 17 ... Tip part, 20 ... Holding member, 21 ... Transmission / reception switching part , 22 ... Bias control unit, 22A ... Transmission bias control unit, 22B ... Reception bias control unit, 23 ... Reception unit, 23A ... Amplification unit, 23B ... Conversion unit, 23C ... Reception beamformer generation unit, 23D ... Signal processing unit , 24 ... transmission unit, 24A ... delay circuit, 24B ... transmission waveform generation unit, 25 ... control unit, 30 ... ultrasonic unit, 60 ... ultrasonic element, 61 ... transmission / reception unit, 80 ... cable

Claims (7)

An ultrasonic observation apparatus in which an ultrasonic unit in which a plurality of capacitive ultrasonic elements are arranged is connected to an ultrasonic endoscope arranged in a distal end portion of an insertion portion,
A transmitter that generates a transmission signal that is converted into an ultrasonic wave transmitted from an element for transmission that is at least one of the plurality of ultrasonic elements;
A reception unit that processes a reception signal in which a reflected wave of an ultrasonic wave transmitted from the transmission element is converted into an electrical signal;
The reflected ultrasonic wave transmitted from the transmitting element is not received by the transmitting element, but is received by a receiving element that is another ultrasonic element disposed in proximity to the transmitting element. A transmission / reception switching unit that switches an ultrasonic element connected to the transmission unit or the reception unit,
A transmission bias controller for applying a transmission DC bias voltage to the transmission element;
A receiving bias control unit that applies a receiving DC bias voltage different from the transmitting DC bias voltage to the receiving element ;
In the ultrasonic element, a plurality of ultrasonic cells in which the upper electrode is arranged to face the lower electrode through the cavity are arranged in a matrix,
The rectangular elements having a width W and a length L (W <L) are arranged at a predetermined interval D that is at least twice as large as the diameter R of the cavity of the ultrasonic cell so that their longitudinal directions are adjacent to each other. An ultrasonic observation apparatus.   The ultrasonic observation apparatus according to claim 1, wherein the transmission / reception switching unit performs switching so that another ultrasonic element arranged adjacent to the ultrasonic element that transmits the ultrasonic wave receives the ultrasonic wave.   The ultrasonic observation according to claim 1, wherein the transmission / reception switching unit sequentially switches ultrasonic elements connected to the transmission unit or the reception unit in a scanning direction of the ultrasonic unit. apparatus.   4. The ultrasonic observation apparatus according to claim 1, wherein the transmission / reception switching unit simultaneously connects a plurality of ultrasonic elements to at least one of the transmission unit and the reception unit. 5. . An ultrasonic observation apparatus in which an ultrasonic unit in which a plurality of capacitive ultrasonic elements are arranged is connected to an ultrasonic endoscope arranged in a distal end portion of an insertion portion,
In order to transmit ultrasonic waves from the ultrasonic element, a transmission unit that generates a transmission signal converted into ultrasonic waves,
In order to receive the ultrasonic wave by the ultrasonic element, a receiving unit that processes a reception signal converted from the ultrasonic wave,
A transmission bias control unit that is provided in the transmission unit and applies a DC bias voltage for transmission to an ultrasonic element connected to the transmission unit;
A reception bias control unit that is provided in the reception unit and applies a reception DC bias voltage different from the transmission DC bias voltage to an ultrasonic element connected to the reception unit;
A state in which the transmission bias control unit generates the transmission bias voltage generated by the transmission bias control unit to transmit the transmission signal to the ultrasonic element, and the reception to the ultrasonic element. A transmission / reception switching unit that switches between a state connected to the reception unit so as to receive a reception signal by applying the reception DC bias voltage generated by the bias control unit;
Have,
In the ultrasonic element, a plurality of ultrasonic cells in which the upper electrode is arranged to face the lower electrode through the cavity are arranged in a matrix,
The rectangular elements having a width W and a length L (W <L) are arranged at a predetermined interval D that is at least twice as large as the diameter R of the cavity of the ultrasonic cell so that their longitudinal directions are adjacent to each other. An ultrasonic observation apparatus. An ultrasonic observation apparatus in which an ultrasonic unit in which a plurality of capacitive ultrasonic elements are arranged is arranged at the distal end of the insertion portion,
A transmission / reception switching unit converts a transmission element that is at least one of the plurality of ultrasonic elements into a transmission bias control unit that applies a DC bias voltage for transmission and ultrasonic waves transmitted from the transmission element. After connecting with the transmitter that generates the transmission signal to be
Reception in which the transmission / reception switching unit applies a reception DC bias voltage different from the transmission DC bias voltage to a reception element that is another ultrasonic element disposed in proximity to the transmission element. A bias control unit and a reception unit that processes a reception signal in which a reflected wave of an ultrasonic wave transmitted from the transmission element is converted into an electrical signal ; and
In the ultrasonic element, a plurality of ultrasonic cells in which the upper electrode is arranged to face the lower electrode through the cavity are arranged in a matrix,
The rectangular elements having a width W and a length L (W <L) are arranged at a predetermined interval D that is at least twice as large as the diameter R of the cavity of the ultrasonic cell so that their longitudinal directions are adjacent to each other. A method for operating an ultrasonic observation apparatus.   The operation method of the ultrasonic observation apparatus according to claim 6, wherein the transmission / reception switching unit performs switching so that the ultrasonic wave is received by another ultrasonic element arranged adjacent to the ultrasonic element that transmitted the ultrasonic wave. .

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