JP2009239976

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DESCRIPTION JP2009239976
The present invention provides an ultrasonic endoscope having a large capacitance of a capacitor
section of a c-MUT cell and high transmission / reception sensitivity. An electrostatic ultrasonic
transducer formed in a semiconductor substrate using a micromachine technique in an ultrasonic
endoscope which is inserted into a body cavity and transmits and receives ultrasonic waves with
an ultrasonic transducer to obtain biological tissue information. And a curved lower electrode
provided by forming a predetermined concave and convex curved surface on a surface of a
substrate constituting the electrostatic ultrasonic transducer, and the concave and convex curved
surface disposed at a position opposed to the curved lower electrode. And a curved upper
electrode exhibiting a substantially identical shape. [Selected figure] Figure 24
Ultrasound endoscope
[0001]
The present invention relates to an ultrasonic endoscope, and more particularly, to an ultrasonic
endoscope that transmits and receives ultrasonic waves with an ultrasonic transducer to obtain
biological tissue information.
[0002]
BACKGROUND ART In recent years, an ultrasonic diagnostic method of irradiating an ultrasonic
wave into a body cavity and imaging and diagnosing a state in the body from an echo signal
thereof is widely used.
[0003]
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As an ultrasonic endoscope apparatus for obtaining an ultrasonic tomographic image in a body
cavity as shown in FIGS. 30 (a) to 30 (c), an illumination optical unit 203 and an observation
optical system are provided at the distal end 202 constituting the insertion unit 201. There is an
ultrasonic endoscope 200 provided with an ultrasonic observation unit 205 together with the
unit 204.
Reference numeral 206 denotes a balloon placement groove in which a balloon (not shown) is
disposed.
[0004]
In the ultrasonic endoscope 200, ultrasonic transducers 207 and 208 for transmitting and
receiving ultrasonic waves are provided at the distal end portion 205.
The ultrasonic transducer 207 shown in FIG. 30 (b) is an electronic scanning type, and the
ultrasonic transducer 207 is configured by arranging a plurality of ultrasonic transducer
elements 207a,..., 207a. Ultrasonic waves are emitted in a direction perpendicular to the axial
direction of the ultrasonic endoscope 200 by scanning the ultrasonic transducer elements
207a,..., 207a linearly or sectorally via an ultrasonic observation device (not shown). A linear or
sector ultrasound tomographic image is displayed on a display (not shown).
[0005]
On the other hand, the ultrasonic transducer 208 shown in FIG. 30C is of a mechanical scanning
type, and the ultrasonic transducer 208 has a housing 209. Then, by mechanically rotating the
housing 209 by the driving force of a drive motor (not shown), ultrasonic waves are emitted in a
direction orthogonal to the axis of the ultrasonic endoscope 200 as the housing 209 rotates. A
radial ultrasound tomographic image is displayed.
[0006]
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As shown in FIG. 31, the ultrasonic transducer 208 uses, for example, a disc-shaped composite
piezoelectric body 211. This composite piezoelectric body 211 is made of a resin such as
polyurethane, epoxy or the like around a gap between a plurality of piezoelectric bodies (not
shown) formed of PZT-based piezoelectric ceramics such as lead zirconate titanate Pb (Zr, Ti) O3
etc. A member (not shown) is filled and configured, and this composite piezoelectric body 211 is
disposed in a metal case body 212.
[0007]
The composite piezoelectric body 211 is provided with a first electrode 211a provided on the
upper surface and a second electrode 211b provided on the lower surface. The second electrode
211 b and the first electrode 211 a are electrically separated, and the upper surface side
provided with the first electrode 211 a is an ultrasonic wave emitting surface. The signal
conductor 213 is connected to the second electrode 211b, and the ground line 214 is connected
to the first electrode 211a.
[0008]
The ultrasonic absorber 215 is disposed on the lower surface side of the composite piezoelectric
member 211 disposed in the case body 212, and an acoustic matching layer covering up to the
tip end surface of the case body 212 on the upper surface side where the curved surface is
formed. An acoustic lens 216 which doubles as an acoustic matching layer that satisfies the
amplitude condition of In addition, an insulating member 217 made of resin is provided on the
outer peripheral side of the ultrasonic absorber 215 and the composite piezoelectric member
211 to prevent electrical contact between the first electrode 211a and the second electrode
211b. Furthermore, the surface of the ultrasonic transducer 208 is covered with a protective film
(not shown) made of parylene (polyparaxylylene) or the like excellent in water resistance and
chemical resistance.
[0009]
On the other hand, as shown in FIG. 32, an ultrasonic transducer 207 in which a plurality of
ultrasonic transducer elements 207a,..., 207a are arranged is made of PZT-based piezoelectric
ceramic or the like such as lead zirconate titanate Pb (Zr, Ti) O3. The piezoelectric element 221
and the backing material 222 disposed on the back side of the piezoelectric element 221 are
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provided. Electrodes 221 a and 221 b are provided on both sides of the piezoelectric element
221. The pattern 223a of the flexible printed board 223 is electrically connected to the electrode
221b by solder (not shown).
[0010]
The piezoelectric elements 221 are separated at equal intervals in a strip shape in the
longitudinal direction by dicing grooves 224 having a depth dimension reaching the backing
material 222 in the thickness direction, and a plurality of transducer elements 207a are arrayed
in the longitudinal direction. Each pattern 223a is connected to two sub-element elements 207b
respectively forming one transducer element 207 by separating the soldered connection parts
from the adjacent connection parts by the dicing grooves 224. An acoustic matching layer (not
shown) is provided on the electrode 221a on the front side, and the electrode 221a on the front
side is connected to the adjacent electrode 221a by a GND wiring material (not shown) and set to
the ground potential.
[0011]
However, in the ultrasonic endoscope, regardless of the electronic scanning type and the
mechanical scanning type, lead is contained in the piezoelectric body constituting the ultrasonic
transducer. For this reason, in view of recent environmental problems, there is a demand for
lead-free ultrasound transducers provided in ultrasound endoscopes that are inserted and used in
body cavities.
[0012]
In addition, in the ultrasonic transducer used in the mechanical scanning type, it is difficult to
always uniformly fill the resin member in the gaps and around the plurality of piezoelectric
members, and the performance varies depending on the creator or the date of manufacture, etc. .
On the other hand, in the case of the electronic scanning ultrasonic transducer, the operation of
forming the dicing groove is skilled, and the performance varies depending on the creator or the
date of manufacture.
[0013]
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Also, conventionally, in an ultrasonic endoscope for obtaining living tissue information by
transmitting and receiving ultrasonic waves with an ultrasonic transducer, as shown in FIG. 23A,
the c-MUT cell 250 has a void 40 in vacuum. Since it is formed, there is a problem that the upper
electrode 37u provided on the membrane 38 is bent and deformed if it is left in the atmosphere
after the c-MUT is formed.
[0014]
The present invention has been made in view of the above circumstances, and in an ultrasonic
endoscope for obtaining biological tissue information by transmitting and receiving ultrasonic
waves with an ultrasonic transducer, the capacitance of the capacitor section of the c-MUT cell is
large. An object of the present invention is to provide an ultrasound endoscope having high
transmission / reception sensitivity.
[0015]
The ultrasonic endoscope according to the present invention is formed by using a micromachine
technique in a semiconductor substrate in an ultrasonic endoscope which is inserted into a body
cavity and transmits and receives ultrasonic waves with an ultrasonic transducer to obtain
biological tissue information. An electrostatic ultrasonic transducer, a curved lower electrode
provided by forming a predetermined uneven curved surface on a surface of a substrate
constituting the electrostatic ultrasonic transducer, and a position opposed to the curved lower
electrode And a curved upper electrode having a shape substantially coinciding with the uneven
curved surface.
[0016]
As described above, according to the present invention, in an ultrasonic endoscope for obtaining
biological tissue information by transmitting and receiving ultrasonic waves with an ultrasonic
transducer, the capacitance of the capacitor section of the c-MUT cell is large and the
transmission and reception sensitivity is high. The object is to provide a high ultrasound
endoscope.
[0017]
The figure explaining the ultrasonic endoscope apparatus which is the 1st embodiment of the
present invention The figure explaining the composition of the tip part of an ultrasonic
endoscope The figure showing an ultrasonic transducer of the ultrasonic transducer The
enlargement of the part shown by arrow A of FIG. Figure and figure explaining the c-MUT cell
figure explaining the configuration example of the cross section of the c-MUT cell block diagram
explaining the configuration of the ultrasonic observation device and the ultrasound transducer
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figure explaining the other configuration example of the c-MUT A diagram for explaining the
arrangement and cell shape of c-MUT cell A diagram for explaining c-MUT with ultrasound
transmission / reception direction on the front A diagram in which the aperture shape of the
ultrasound scanning surface is polygonal shape Figure showing the c-MUT Figure showing the cMUT with the circular shape of the opening of the ultrasound scan plane showing the
transmission / reception direction of the front Figure showing the c-MUT with the through hole
formed the front of the transmission / reception direction Mechanical scanning ultrasound
endoscope FIGS. 14 to 23 illustrate MUTs FIGS. 14 to 23 illustrate a modification of c-MUT
configured by arranging a plurality of c-MUT cells, and FIG. 14 illustrates c-MUT constituting an
ultrasonic transducer. A diagram illustrating another arrangement of cells A diagram illustrating
another arrangement of c-MUT cells constituting an ultrasonic transducer A diagram illustrating
another arrangement of c-MUT cells constituting an ultrasonic transducer Fig. 17 illustrates an
ultrasonic endoscope provided with a c-MUT so as to perform scanning of the inside of the
ultrasonic wave in which a c-MUT is provided on a curved surface portion illustrated in Fig. 17A.
Figure showing a scope c Figure showing a substrate on which a MUT chip is mounted Figure
explaining another example of the configuration of a c-MUT cell Configuration of a c-MUT cell
subjected to a porous treatment, and the porous treatment time and acoustic impedance FIG. 25
illustrates another configuration example of FIG. C-MUT cell illustrates another configuration
example of FIG. C-MUT cell illustrating the relationship of FIG. 25 through FIG. 29 illustrating
another configuration example of the c-MUT cell according to the second embodiment of the
present embodiment; FIG. 25 illustrates an ultrasonic endoscope in which a multi-functional
ultrasonic transducer in which a silicon light emitting element and a silicon light receiving
element are provided on a silicon substrate in addition to a c-MUT. Figure for explaining another
example of the configuration of the multi-functional ultrasonic transducer in which the silicon
light emitting element and the silicon light receiving element are disposed and further, the figure
for explaining the configuration of the multi-functional ultrasonic transducer in which the micro
gyro sensor is disposed Diagram illustrating the configuration of a multi-functional ultrasonic
transducer provided with a capacitance measurement cell on the top Diagram illustrating a
conventional ultrasonic endoscope Figure showing a configuration example of an acoustic
transducer Figure showing a configuration example of an ultrasound scanning ultrasonic
transducer
[0018]
Hereinafter, embodiments of the present invention will be described with reference to the
drawings.
First Embodiment FIG. 1 is a view for explaining an ultrasound endoscope apparatus according to
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a first embodiment of the present invention, FIG. 2 is a view for explaining the configuration of a
distal end portion of the ultrasound endoscope, and FIG. FIG. 4 illustrates an ultrasonic
transducer, FIG. 4 illustrates an enlarged view of a portion indicated by arrow A in FIG. 3 and a
diagram illustrating a c-MUT cell, FIG. 5 illustrates a configuration example of a cross section of
the c-MUT cell, FIG. 6 is a block diagram for explaining the configuration of the ultrasonic
observation apparatus and the ultrasonic transducer, FIG. 7 is a diagram for explaining another
configuration example of the c-MUT, and FIG. 8 is a diagram for explaining the arrangement and
cell shape of the c-MUT cell Fig. 9 is a diagram for explaining the c-MUT in which the ultrasonic
wave transmission / reception direction is forward, and Fig. 10 is a c-MUT in which the
ultrasonic scan plane has a polygonal opening shape. Figure 11 shows the direction of
transmission / reception of the front of the ultrasonic scanning surface with the circular opening.
Figure 12 shows the c-MUT, Figure 12 shows the c-MUT with the through hole formed in the
forward / outgoing direction, Figure 13 explains the c-MUT of the mechanical scanning
ultrasound endoscope FIG.
[0019]
8 (a) shows the c-MUT cells arranged in a lattice, FIG. 8 (b) shows another cell shape of the cMUT cell, and FIG. 8 (c) shows the c-MUT cell. Fig. 13 (a) shows another cell shape of the cell, Fig.
13 (a) shows a mechanical scanning c-MUT, Fig. 13 (b) shows a mechanical scanning ultrasonic
endoscope in which the c-MUT is arranged. FIG.
[0020]
As shown in FIG. 1, the ultrasonic endoscope apparatus 1 of this embodiment includes an
ultrasonic endoscope (hereinafter abbreviated as an endoscope) 2 including an electrostatic
ultrasonic transducer described later, and illumination light. A light source unit (not shown) to be
supplied and a signal processing unit for driving an imaging device (not shown) and performing
various signal processing of electric signals transmitted from the imaging device to generate a
video signal for an endoscopic observation image A signal for generating a video signal for an
ultrasonic tomographic image by performing various signal processing of an endoscopic
observation device 3, driving of the electrostatic ultrasonic transducer, and an electric signal
transmitted from the electrostatic ultrasonic transducer An ultrasonic observation apparatus 4
having a processing unit, and a monitor 5 for displaying an observation image based on the
ultrasonic observation apparatus 4 and a video signal generated by the endoscopic observation
apparatus 3 are mainly configured. It is done.
[0021]
The endoscope 2 has an elongated insertion portion 11 inserted into a body cavity, an operation
portion 12 positioned on the proximal end side of the insertion portion 11, and a universal cord
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13 extending from the side portion of the operation portion 12 And is mainly composed of.
[0022]
An endoscope connector 14 connected to the endoscope observation device 3 is provided at a
proximal end of the universal cord 13.
A lighting connector 14a connected to the light source of the endoscope observation device 3 is
provided at the tip of the endoscope connector 14, and an electric cord (not shown) is electrically
connected to the signal processor on the side. An electrical connector 14b is provided, to which
the connector is detachably connected.
In addition, an ultrasonic cable 15 having an ultrasonic connector 15a electrically connected to
the ultrasonic observation device 4 extends from the proximal end of the endoscope connector
14.
[0023]
The insertion portion 11 includes a distal end rigid portion 6 formed of a hard member in order
from the distal end, a bendable curved portion 7 continuously provided on the proximal end side
of the distal end rigid portion 6, and a proximal end side of the curved portion 7 And a flexible
tube portion 8 having flexibility and having a small diameter and a long length leading to the
distal end side of the operation portion 12.
[0024]
The distal end rigid portion 6 includes an endoscopic observation unit 20 in which an
observation optical unit for performing endoscopic observation by direct vision and an
illumination optical unit is arranged, and a plurality of ultrasonic transducer elements for
transmitting and receiving ultrasonic waves to perform ultrasonic waves. The ultrasonic
observation unit 30 which formed the scanning surface is provided.
[0025]
The operation unit 12 includes an angle knob 16 for controlling the bending of the bending unit
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7, an air supply / water supply button 17a for performing air supply and water supply
operations, a suction button 17b for performing suction operation, and a treatment for
introducing into a body cavity A treatment tool insertion port 18 or the like which is an inlet of
the tool is provided.
There are provided various operation switches 19 for switching display images to be displayed
on the monitor 5, and instructing freeze, release and the like.
Reference numeral 9 is a mouthpiece disposed in the oral cavity of the patient.
[0026]
As shown in FIG. 2, an ultrasonic observation unit 30 for performing ultrasonic observation is
disposed on the distal end side of the distal end rigid portion 6.
Further, a slope portion 21 is formed on the tip rigid portion 6, and the slope portion 21 is
provided with an illumination lens cover 22 constituting an illumination optical portion for
irradiating illumination light to the observation site, and an optical image of the observation site
A lens cover 23 for observation which constitutes an observation optical unit, and a forceps
outlet 24 which is an opening from which the treatment tool introduced from the treatment tool
insertion port 18 protrudes are provided.
[0027]
A circumferential balloon groove 25 for attaching, if necessary, a balloon (not shown) formed in a
flexible manner to the distal end rigid portion 6 by a latex or Teflon (R) (R) rubber or the like
which has ultrasonic wave permeability and which can freely expand and contract. Is formed.
Further, in the vicinity of the balloon groove 25, there is provided a pipeline opening (not shown)
for supplying and draining water as an ultrasonic transmission medium into the balloon.
[0028]
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A light guide fiber (not shown) for transmitting illumination light from a light source unit
provided in the endoscope observation device 3 is faced to the illumination lens cover 22, and
the observation lens cover 23 is A solid-state imaging device (not shown) for extending a signal
cable (not shown) is disposed at the imaging position.
[0029]
The ultrasonic observation unit 30 mainly includes an ultrasonic transducer 31 for transmitting
and receiving ultrasonic waves, and a housing portion 32 which accommodates the ultrasonic
transducer 31 and is fixed to the distal end rigid portion 6. .
[0030]
The ultrasonic transducer 31 shown in FIGS. 2 and 3 is also described as an electrostatic
ultrasonic transducer (hereinafter referred to as c-MUT (Capacitive Micromachined Ultrasonic
Transducer) 31 in which a silicon semiconductor substrate is processed using silicon
micromachining technology. And not manually, in a silicon process, it is automatically
manufactured faithfully according to the operation sequence in a completely clean environment.
[0031]
The c-MUT 31 is formed, for example, as a square sector type by arranging a plurality of c-MUT
cells 31a.
The c-MUT cells 31a, ..., 31a of the c-MUT 31 and the signal lines 33, ..., 33 are electrically
connected via the cable connection portion 34.
The signal lines 33,..., 33 extending from the cable connection portion 34 are put together and
extend in the direction of the operation portion 12 in a state of being inserted into, for example, a
tube (not shown). The ultrasonic observation device 4 is electrically connected.
[0032]
A convex portion 32b having a circumferential balloon groove 32a for attaching a balloon (not
shown) as necessary is provided at the distal end portion of the housing portion 32.
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Further, the surface of the c-MUT 31 and a part of the housing portion 32 are made of a
protective film formed of parylene (polyparaxylylene) or the like excellent in water resistance and
chemical resistance (see reference numeral 39 in FIG. 4). It is covered.
[0033]
As shown in FIGS. 4 and 7, the cell shape of each c-MUT cell 31a constituting the c-MUT 31 is
formed, for example, in a hexagonal shape.
The plurality of c-MUT cells 31a, ..., 31a are arranged in a honeycomb structure with a plurality
of rows and a plurality of rows at a minute predetermined pitch, and the opening shape of the
ultrasonic scanning surface is, for example, a square.
[0034]
The c-MUT cell 31a is mainly composed of a lower electrode 37d formed on a silicon substrate
35, an insulating support 36 for setting the distance between the electrodes, a silicon membrane
38 formed of silicon or a silicon compound, and an upper electrode 37u. Is configured.
The lower electrode 37 d is provided on the upper surface of the silicon substrate 35, and the
upper electrode 37 u is provided on the upper surface of the silicon membrane 38.
Reference numeral 40 denotes a vacuum gap (hereinafter referred to as a gap), which is a
damping layer of the silicon membrane 38 in the present embodiment.
[0035]
On a silicon substrate 35 on which a plurality of c-MUT cells 31a are arranged, an access circuit
forming portion 43 provided with an access circuit formed of a c-MOS integrated circuit, and a
wiring electrode 44 are provided. The upper electrode 37 u provided on the silicon membrane
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38 is a ground electrode, and the lower electrode 37 d is a signal input / output electrode. The
upper surface of the upper electrode 37u is covered with the protective film 39.
[0036]
As shown in FIG. 2, a plurality of c-MUT cells 31a are arranged in the c-MUT 31 shown in FIG.
The c-MUT cells 31 a are driven and controlled based on an operation instruction signal output
from the CPU 51 provided in the ultrasonic observation apparatus 4.
[0037]
The ultrasonic observation apparatus 4 includes the CPU 51, the trigger signal generation circuit
52, the selector 53, the echo signal processing circuit 54, the Doppler signal processing circuit
55, the harmonic signal processing circuit 56, and the ultrasonic image processing unit as shown
in FIG. 57, a transmission delay circuit 61, a bias signal application circuit 62, a drive signal
generation circuit 63, a transmission / reception switching circuit 64, and a c-MUT cell 31a are
provided with a preamplifier 65 and a beam former 66.
[0038]
The CPU 51 outputs operation instruction signals to various circuits and processing units
provided in the ultrasonic observation apparatus 4 and receives feedback signals from the
various circuits and processing units to perform various controls.
[0039]
The trigger signal generation circuit 52 drives each c-MUT cell 31a to output a repetitive pulse
signal which is a timing signal of transmission and reception.
The selector 53 transmits a pulse signal to a predetermined c-MUT cell 31a instructed based on
an operation instruction signal of the CPU 51.
[0040]
The echo signal processing circuit 54 reflects an ultrasonic wave output from each c-MUT cell
31a at an organ in the living body and its boundary, etc., and returns to the c-MUT cell 31a to be
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received as described later. Image data of a visible image is generated based on the signal.
[0041]
The Doppler signal processing circuit 55 extracts a movement component of tissue, that is, a
blood flow component from the reception beam signal output from the c-MUT cell 31a by using
the Doppler effect, and the blood flow component in the ultrasonic tomographic image Generate
color data to color the position.
[0042]
The harmonic signal processing circuit 56 extracts and amplifies the signal of the frequency
component from the reception beam signal output from each c-MUT cell 31a with a filter having
the second harmonic frequency or the third harmonic frequency as the center frequency. And
generate image data for harmonic imaging diagnosis.
[0043]
The ultrasonic image processing unit 57 uses the image data generated by the echo signal
processing circuit 54, the Doppler signal processing circuit 55, the harmonic signal processing
circuit 56, etc., to generate a B-mode image, a Doppler image, and harmonic imaging,
respectively. Build an image etc.
At the same time, the CPU 51 overlays characters such as characters.
Then, the video signal constructed by the ultrasonic image processing unit 57 is output to the
monitor 5, and an ultrasonic tomographic image which is one of observation images is displayed
on the screen of the monitor 5.
[0044]
The transmission delay circuit 61 determines the timing for applying a drive voltage to each cMUT cell 31a, and sets a predetermined sector scan and the like.
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The bias signal application circuit 62 applies a predetermined bias signal to the drive signal
generation circuit 63.
As this bias signal, the same DC voltage is used at the time of transmission and reception, the
voltage is set to a high voltage at transmission and is changed to a low voltage at reception, for
example, the one obtained by superimposing an AC component on the DC component for
correlation There is.
[0045]
The DC bias voltage is necessary to obtain an ultrasonic transmission waveform having the same
waveform as the transmission voltage waveform at the time of transmission. If the DC bias
voltage is not superimposed, the frequency of the transmission ultrasonic signal is twice that of
the drive voltage signal, and its amplitude is one half.
[0046]
On the other hand, it is essential to apply a bias voltage during reception. This bias voltage has
the same waveform as that of the received ultrasonic wave if it is a DC voltage. Further, it is also
possible to superimpose an AC voltage signal together with the DC voltage and to filter by a band
pass filter at the center frequency of the AC voltage signal by signal processing in the subsequent
stage to improve SN. Furthermore, c-MUT cell selection becomes possible as another utilization
method of bias voltage application. This utilizes the fact that the reception signal can not be
obtained in principle without a bias voltage, and cell selection becomes possible by not applying
a DC voltage to a cell that does not perform cell selection. Become. The received signal on which
the direct current signal component is superimposed is converted into an rf signal by a direct
current signal blocking means such as a capacitor, and is converted to a received signal and
transmitted to the signal processing unit.
[0047]
The drive signal generation circuit 63 generates a burst wave which is a drive voltage signal
corresponding to a desired ultrasonic waveform based on the output signal from the
transmission delay circuit 61. The transmission / reception switching circuit 64 switches one c-
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MUT cell 31a between the transmission state and the reception state. In the transmitting state,
the drive voltage signal is applied to the c-MUT cell 31a, and in the receiving state, the charge
information generated between the electrodes 37u and 37d of the c-MUT cell 31a is received by
receiving the echo information. Output.
[0048]
The preamplifier 65 converts the charge signal output from the transmission / reception
switching circuit 64 into a voltage signal and amplifies it. The beam former 66 outputs a
reception beam signal obtained by combining the ultrasonic echo signals output from the
preamplifier 65 with a delay time which is the same as or different from the delay in the
transmission delay circuit 61.
[0049]
Then, based on the operation instruction signal of the CPU 51, a predetermined phase difference
is given to drive each c-MUT cell 31a to set the predetermined focal distance from the ultrasonic
scanning surface of the ultrasonic observation unit 30. The ultrasonic wave by the ultrasonic
wave set to the focal distance by transmitting the sound wave and combining the same delay by
the beam former 66 with the delay in the transmission delay circuit 61 and outputting it as a
reception beam signal We can observe it.
[0050]
The beamformer 66 synthesizes and outputs with a desired delay time different from the delay in
the transmission delay circuit 61, thereby obtaining a reception beam signal corresponding to
the delay time of the beamformer 66, and observing an ultrasonic wave. A desired ultrasonic
tomographic image can be obtained through the device 4.
[0051]
Further, in the present embodiment, the c-MUT 31 in a layered arrangement in which the control
circuits and the wiring electrodes of the plurality of c-MUT cells 31a are formed on the first
intermediate dielectric layer 41 and the second intermediate dielectric layer 42 of the silicon
substrate 35. However, the configuration of the c-MUT 31 is not limited to a layered
arrangement, and as shown in FIG. 7, a c-MUT cell forming portion in which a plurality of c-MUT
cells 31a are arranged on one side of the c-MUT 31 An in-plane ultrasonic transducer 31A may
be configured to be provided with a circuit formation portion 31c in which 31b and the control
circuit, the wiring electrode and the like are formed.
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[0052]
Furthermore, in the present embodiment, the cell shape of the c-MUT cell 31a is formed in a
hexagonal shape, and they are arranged in a honeycomb structure, but the shape and
arrangement of the c-MUT cell 31a are limited to this. The configuration is such that a plurality
of c-MUT cells 31a are arranged in a grid as shown in FIG. 8 (a), or a circular or elliptical shape
(not shown in FIG. 8 (b)). The c-MUT cell 31 d may be formed in the drawing) or the c-MUT cell
31 e may be formed in a polygonal shape such as an octagonal shape as shown in FIG.
[0053]
Further, in the present embodiment, the ultrasonic wave emitted from the ultrasonic scanning
surface of the c-MUT 31 configured by arranging a plurality of c-MUT cells 31 a is substantially
orthogonal to the longitudinal axis direction of the ultrasonic endoscope 2 The signal line 33
extending from the c-MUT 31 is extended from the back side of the ultrasonic scanning surface
to make the c-MUT 31 B as shown in FIG. 9A. Thus, as shown in FIG. 9 (b), the c-MUT 31B is
disposed on the distal end surface 11a of the insertion portion having the endoscope observation
portion 20A of the forward-view type, so that the ultrasonic wave emitted from the ultrasonic
scanning surface An ultrasonic endoscope 2A of a square sector electronic scan type in a front
view in which the insertion direction of the insertion portion 11 is set to the front can be
configured.
[0054]
Further, in the present embodiment, the c-MUT cells 31a are aligned and arranged so that the
aperture shape of the ultrasonic scanning surface is a quadrangular shape, but in the ultrasonic
scanning surface formed by aligning the c-MUT cells 31a. The shape of the opening and the size
of the opening are not limited to those shown in the figure, and may form a polygonal c-MUT 31
C such as an octagon shape as shown in FIG. The c-MUT 31D may have a circular shape as
shown in (a) or an elliptical shape (not shown).
[0055]
Then, the c-MUTs 31C and 31D are disposed on the insertion portion distal end surface 11a as
shown in FIGS. 10 (b) and 11 (b) to configure an ultrasonic endoscope 2B of polygonal sector
electron scan type in front view. Alternatively, a forward looking circular sector electronic scan
type ultrasonic endoscope 2C may be configured.
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At this time, the shape of the cable connection portion 34 is changed in accordance with the
shape of the c-MUT.
[0056]
The operation of the ultrasound endoscope in which the c-MUT configured as described above is
provided in the ultrasound observation unit will be described.
The insertion portion 11 is inserted into the body cavity while observing the endoscopic image
displayed on the screen of the monitor 5 of the ultrasonic endoscope apparatus 1.
Then, when the distal end rigid portion 6 of the insertion portion 11 is disposed in the vicinity of
the observation site, for example, the balloon (not shown) is expanded and the c-MUT 31 is
driven by operating the ultrasonic observation device 4.
[0057]
Then, an operation instruction signal corresponding to the operation instruction of the observer
is output from the CPU 51 of the ultrasonic observation device 4, converted into a pulse signal by
the trigger signal generation circuit 52, and c-MUT 31 is configured via the selector 53. It is
output toward a predetermined c-MUT cell 31a.
[0058]
The pulse signal is input to the transmission delay circuit 61, and the drive voltage signal
subjected to a predetermined delay is output through the drive signal generation circuit 63 and
the bias signal application circuit 62, and switched to the transmission state by the transmission
/ reception switching circuit 64. When this is done, this drive voltage signal is applied to the cMUT cell 31a to emit an ultrasonic wave.
[0059]
Then, the CPU 51 outputs an operation instruction signal to each of the arranged c-MUT cells
31a, for example, delays the drive voltage signal to the central c-MUT cell 31a to a large extent,
and A single ultrasonic waveform is formed by, for example, applying a small delay to the drive
voltage signal with respect to the c-MUT cell 31a going away from the c-MUT cell 31a, and
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output from the ultrasonic scan surface of the c-MUT 31.
[0060]
That is, ultrasonic waves are emitted from the c-MUT cells 31a based on the control of the CPU
51, and sector scanning in the axial direction and sector scanning in the direction orthogonal to
the axial direction can be performed.
[0061]
On the other hand, in these c-MUT cells 31a, the transmission / reception state is switched and
controlled by the transmission / reception switching circuit 64.
Therefore, when the transmission / reception switching circuit 64 is in the receiving state, the
charge signal generated between the electrodes 37 u and 37 d is output to the preamplifier 65 as
the c-MUT cell 31 a receives the echo information.
[0062]
The charge signal output to the preamplifier 65 is converted into a voltage signal and amplified,
and is output to the ultrasonic observation apparatus 4 as a reception beam signal which is
appropriately delayed by the beam former 66.
[0063]
The reception beam signals sequentially output from the c-MUT cells 31a are subjected to
predetermined processing through the echo signal processing circuit 54, the Doppler signal
processing circuit 55, the harmonic signal processing circuit 56 and the like, and then ultrasonic
image processing At the same time as conversion to a standard video signal in the unit 57,
overlay is performed via the CPU 51 and output to the monitor 5.
As a result, an ultrasonic tomographic image is displayed on the screen of the monitor 5 together
with the endoscopic image, or an ultrasonic tomographic image is displayed in place of the
endoscopic image.
04-05-2019
18
This enables ultrasonic observation of the target observation site.
[0064]
As described above, the ultrasonic transducers disposed in the ultrasonic observation unit
provided at the distal end of the ultrasonic endoscope are arrayed with a plurality of c-MUT cells
using silicon semiconductor substrate and silicon micromachining technology. Further, by using
an electrostatic ultrasonic transducer, a lead-free ultrasonic transducer can be realized.
[0065]
Also, by using silicon micromachining technology, electrostatic ultrasonic transducers can be
created automatically in a clean environment.
As a result, since a fine c-MUT cell arrangement can be performed without causing dicing
distortion or variation, a highly reliable ultrasound observation unit can be provided at low cost.
[0066]
Furthermore, the cell shape of the c-MUT cell and the aperture shape of the ultrasonic scanning
surface can be set to a desired shape and size, so that miniaturization and high precision of the
ultrasonic observation unit can be achieved.
[0067]
As shown in FIG. 12A, a ring-shaped c-MUT 31E may be formed, and a through hole 24a may be
formed in a substantially central portion of the c-MUT 31E.
In the present embodiment, the signal line 33 is extended from the edge side of the cable
connection portion 34 in order to form the through hole 24 a.
[0068]
Then, the c-MUT 31E having the through hole 24a is disposed, for example, on the distal end
04-05-2019
19
surface 11a of the insertion portion as shown in FIG. 12 (b), so that the through hole 24a is used
as the forceps outlet 24 of the treatment tool channel. A sound wave endoscope 2D can be
configured.
[0069]
Further, although the ultrasonic endoscope provided with the electronic scanning ultrasonic
transducer has been described in the above-described embodiment, in the mechanical scanning
ultrasonic endoscope as well, the ultrasonic transducer may be configured by c-MUT. You may
[0070]
Specifically, as shown in FIG. 13A, c-MUT cells 31a are arrayed to form an ultrasonic scanning
surface in a disk shape to form c-MUT 31F.
At this time, the upper electrodes 37u and the lower electrodes 37d constituting the c-MUT cell
31a are electrically connected to each other, and the housing 73 rotatably supported by the drive
member 72 in the housing portion 71 is used. It arrange ¦ positions and the ultrasonic endoscope
70 is comprised.
A signal line (not shown) extending from the c-MUT 31F passes through the inside of the drive
member 72 and is electrically connected to the ultrasonic observation apparatus 4.
[0071]
With the insertion portion 11 of the ultrasonic endoscope 70 inserted into the body cavity, the
housing 73 is rotated by the driving force of a driving motor (not shown), and the ultrasonic
driving signal is transmitted from the ultrasonic observation device 4 to c- Output to the MUT
31F.
As a result, the c-MUT 31F performs radial scanning while transmitting and receiving ultrasonic
waves, converts echo information on the tomographic plane into electrical signals, and outputs
the electric signals to the ultrasonic observation apparatus 4 as reception beam signals.
04-05-2019
20
The rotational angle of the housing 73 is detected by a rotary encoder 74 that detects the
rotation of the drive member 72.
That is, the rotation angle of the c-MUT 31F is sequentially output to the ultrasonic observation
apparatus 4 together with the reception beam signal as a rotation angle signal.
[0072]
Therefore, the ultrasonic observation apparatus 4 performs various processes such as envelope
detection, logarithmic amplification, A / D conversion, and the like on the obtained reception
beam signal, and further performs polar coordinate system based on the rotation angle signal.
The digital echo data is converted to a Cartesian coordinate system that can be output to the
monitor 5, and a video signal for constructing an ultrasonic tomographic image is generated and
output to the monitor 5.
By this, an ultrasonic tomographic image can be displayed on the screen of the monitor 5, and
ultrasonic observation of a target observation region can be performed.
[0073]
Here, a modification of the c-MUT configured by arranging a plurality of c-MUT cells 31a will be
described with reference to FIGS.
[0074]
Another arrangement of c-MUT cells constituting an ultrasonic transducer will be described with
reference to FIG.
FIG. 14 (a) is a diagram showing an ultrasonic transducer configured by arranging c-MUT cells in
which the aperture size is changed according to a predetermined rule, and FIG. 14 (b) is the A1A2 direction of the c-MUT cell. FIG. 14C is a view showing an aperture distribution curve
regulating the B1-B2 directional alignment of the c-MUT cell.
04-05-2019
21
[0075]
As shown in FIG. 14A, in the c-MUT 31G of the present embodiment, the opening size of each cMUT cell 31 constituting the c-MUT 31G is regularly changed depending on the arrangement
direction.
That is, instead of forming all the opening dimensions of the c-MUT cell 31a constant as in the
embodiment described above, for example, R value distribution curves shown in FIGS. 14 (b) and
14 (c) according to the arrangement direction. It is set based on.
[0076]
The R value distribution curves shown in FIGS. 14 (b) and 14 (c) apply that the electrode area in
the c-MUT cell is proportional to the electrostatic capacity and, as a result, proportional to the
transmission and reception sound pressure. In this case, the electrode area is set to, for example,
a Gaussian distribution function. That is, in the c-MUT 31G of the present embodiment, the
opening dimension of the c-MUT cell 31a located at the center is maximized, and the opening
dimension is the same as the curve from the center toward the periphery of the c-MUT 31G. It is
getting smaller.
[0077]
By this, the directivity characteristic (= diffraction pattern of the aperture of this element)
indicated by the c-MUT cell is multiplied by the interference pattern generated by the mutual
interference effect when the c-MUT cells are arranged in an array. Grating lobes, which are
strong and weak in directional characteristics that occur, can be improved to suppress the
generation of artifacts that are pseudo information. Therefore, a good ultrasonic tomographic
image can be obtained.
[0078]
Another arrangement of the c-MUT cell constituting the ultrasonic transducer will be described
04-05-2019
22
with reference to FIG. FIG. 15 (a) is a diagram showing an example of a configuration in which cMUT cells to be arranged are divided into transmission cells, reception cells and non-use cells,
and FIG. 15 (b) is c-MUTs to be arranged. It is a figure which shows the other structural example
which divided ¦ segmented the cell into the cell for transmission, the cell for reception, and a
non-use cell.
[0079]
In the embodiment described above, transmission / reception is performed by one c-MUT cell 31
a by providing the transmission / reception switching circuit 64 to switch between the
transmission state and the reception state, but in the present embodiment, a plurality of c The
MUT cell is a transmission cell 31 f dedicated to transmission, a reception cell 31 g dedicated to
reception, and a non-use cell 31 h having neither transmission nor reception functions.
[0080]
Then, as shown in FIG. 15A, a transmission / reception cell group 31k and a nonuse cell 31h
configured by a pair of transmission cells 31f and a reception cell 31g are formed as a nonuse
cell group 31m which is a band group, The non-use cell group 31m and the transmission /
reception cell group 31k are alternately arranged, for example, in the column direction to
constitute the c-MUT 31H.
[0081]
As a result, between transmission cell group 31f or reception cell group 31g arranged in the
column direction, reception cell group 31g and non-use cell group 31h at transmission time and
transmission cell group 31f at reception time are not used. Cross talk can be reduced by
providing the cell group 31 h with a physical predetermined interval.
Therefore, an ultrasonic tomographic image with good image quality can be obtained.
[0082]
Here, instead of configuring the transmission / reception cell group 31k with a pair of
transmission cells 31f and reception cells 31g, as shown in FIG. 15 (b), transmission / reception
is performed by two transmission cells 31f and one reception cell 31g. For example, an
approximately band-like non-use cell group 31m is arranged between the transmission /
reception cell groups 31n arranged in the row direction, and a physical predetermined interval is
04-05-2019
23
set between adjacent transmission / reception cell groups 31n. The c-MUT 31 J may be
configured to be provided.
[0083]
In the present embodiment, the c-MUT cells constituting the c-MUT are shown as the reception
cell 31g, the transmission cell 31f, and the non-use cell 31h. However, each of the plurality of
reception cells 31g is illustrated. The electrodes are integrally and electrically connected to form
a reception cell group, and the electrodes of the plurality of transmission cells 31f are integrally
electrically connected to form a transmission cell group and the non-use cell group. Alternatively,
the c-MUT may be configured by arranging the respective cell groups as shown in FIG. 15 (a) and
FIG. 15 (b).
[0084]
Another arrangement of the c-MUT cell constituting the ultrasonic transducer will be described
with reference to FIG.
FIG. 16 (a) shows a configuration in which the c-MUT cell is divided into a transmission group
and a reception group, and FIG. 16 (b) is a transmission cell of the transmission group indicated
by arrow B in FIG. 16 (a). FIG. 16C is an enlarged view for explaining the arrangement of the
group and the non-use cell group, and FIG. 16C illustrates the arrangement of the reception cell
group and the non-use cell group of the reception group shown by arrow C in FIG. It is an
enlarged view.
[0085]
As shown in FIG. 16A, the c-MUT 31K of the present embodiment is provided with two ringshaped cell groups formed by arranging a plurality of c-MUT cells 31a.
Of the two ring-shaped cell groups, for example, a ring-shaped cell group disposed outside is
configured as a transmission group 31p, and a ring-shaped cell group disposed inside is
configured as a reception group 31s.
04-05-2019
24
[0086]
Then, as shown in FIG. 16 (b), in the transmission group 31p, the electrodes of a series of
transmission cells 31f are electrically connected to each other from among the c-MUT cells 31a
to be arranged, as shown in FIG. A transmission cell group (hereinafter also referred to as an
active group) 31q having a shape shown by a colored portion is formed as a plurality of non-use
cells 31h as shown by white portions in the figure. Are formed as an unused cell group 31r
having a physical space between them.
Then, the unused cell group 31 r and the transmission cell group 31 q are alternately arranged
to constitute a transmission group 31 p.
[0087]
On the other hand, as shown in FIG. 16C, in the reception group 31s, the electrodes of the series
of reception cells 31g are electrically connected to each other from among the c-MUT cells 31a
to be arranged, and The receiving cell group 31t (hereinafter also referred to as an active group)
having a shape shown by a colored portion is formed, and a plurality of non-use cells 31h are
shown by white portions in the figure. Are formed as an unused cell group (hereinafter also
referred to as an inactive group) 31r having a physical distance between them. Then, the non-use
cell group 31r and the reception cell group 31t are alternately arranged to constitute a reception
group 31s.
[0088]
As a result, the c-MUT 31 K can be provided in a state in which the transmission group 31 p for
transmitting ultrasonic waves and the reception group 31 s for receiving ultrasonic waves are
separated. Further, by arranging the transmission group 31p and the reception group 31s
alternately by arranging the active group and the inactive group, a physical predetermined
interval is provided between the adjacent active groups to thereby prevent crosstalk. It can be
mitigated. Therefore, an ultrasonic tomographic image with good image quality can be obtained.
[0089]
04-05-2019
25
Another configuration of the ultrasonic observation unit provided in the ultrasonic endoscope
will be described with reference to FIGS. 17 and 18. FIG. 17 (a) is a view for explaining the
configuration of an ultrasound endoscope provided with a c-MUT capable of scanning in two
directions in the ultrasound observation unit, and FIG. 17 (b) is a scanning direction in the
ultrasound observation unit 18 (a) shows the configuration of the c-MUT shown in FIG. 17 (a),
FIG. 18 (b) shows another configuration of the ultrasound endoscope provided with different cMUTs. 18 (a) is an enlarged view for explaining the arrangement of the portion indicated by the
arrow D of the c-MUT in FIG. 18 (a), and FIG. 18 (c) is an explanation of the arrangement of the
portion indicated by the arrow E in the c-MUT of FIG. It is a figure to do.
[0090]
As shown in FIG. 17A, in the ultrasonic endoscope 2E of the present embodiment, the housing
portion 32 includes a first ultrasonic scan surface 81 which can perform sector scanning in the
axial direction and sectors in a direction orthogonal to the axial direction. There is provided a biplane type c-MUT 31L integrally provided with a second ultrasonic scan surface 82 capable of
scanning as an ultrasonic scan surface.
[0091]
As shown in FIGS. 18A and 18B, the second ultrasonic scan surface 82 is formed in a band shape
by electrically connecting the electrodes of a plurality of c-MUT cells 31a for transmitting and
receiving ultrasonic waves. The transmission / reception cell group 83 and the non-use cell 31h
not having the ultrasonic wave transmission / reception function are formed in a band shape, and
a physical predetermined interval is provided between adjacent transmission / reception cell
groups 83 to prevent crosstalk. It is comprised with the non-use cell group 84 which aims at
reduction.
The transmission / reception cell group 83 and the non-use cell group 84 are alternately
arranged in the arrow F direction.
[0092]
On the other hand, as shown in FIGS. 18 (a) and 18 (c), the first ultrasonic scan surface 81 is
formed into a strip by electrically connecting the electrodes of a plurality of c-MUT cells 31a for
04-05-2019
26
ultrasonic transmission and reception. The formed transmission / reception cell group 83 and
the non-use cell 31h not having an ultrasonic wave transmission / reception function are formed
in a band shape, and physical predetermined intervals are provided between adjacent
transmission / reception cell groups 83 to cross each other. The nonuse cell group 84 is
configured to reduce talk. The transmission / reception cell group 83 and the non-use cell group
84 are alternately arranged in the arrow G direction.
[0093]
This makes it possible to obtain ultrasound tomographic images scanned in multiple directions
using one ultrasound endoscope. In addition, as shown in FIG. 17B, the c-MUT 31M in which the
scanning direction is the axial direction and the scanning direction is the axial direction in the tip
end surface portion and the side surface portion of the housing portion 32 which configures the
ultrasonic observation unit 30. The ultrasonic endoscope 2F may be configured by arranging cMUTs 31N that are orthogonal to each other. This makes it possible to obtain ultrasound
tomographic images scanned in multiple directions using one ultrasound endoscope. In addition,
the scanning direction of the c-MUT disposed on the front end surface portion and the side
surface portion of the housing 32 is the axial direction, or orthogonal to the axial direction, or the
biplane shown in FIG. By appropriately selecting and providing the type, a desired ultrasonic
tomographic image can be obtained and ultrasonic observation of a target site can be performed.
[0094]
Ultrasonic wave provided to the ultrasonic endoscope with reference to a diagram showing an
ultrasonic endoscope provided with a c-MUT in the curved portion in FIG. 19 and a drawing for
explaining a substrate on which the c-MUT chip is mounted in FIG. Another configuration of the
observation unit will be described. 19 (a) shows a convex scanning type ultrasonic endoscope,
FIG. 19 (b) shows a radial scanning type ultrasonic endoscope, and FIG. 20 (a) shows a c-MUT
chip. FIG. 20 (b) shows an example of the mounting substrate, FIG. 20 (b) shows the operation of
the c-MUT chip mounting substrate shown in FIG. 20 (a), and FIG. 20 (c) shows the other
components of the c-MUT chip mounting substrate. It is a figure which shows the structural
example of.
[0095]
04-05-2019
27
As shown in FIG. 19 (a), the ultrasonic endoscope 2G of the present embodiment arranges the
curved surface shape c-MUT 91 at the tip of the housing portion 32 constituting the ultrasonic
observation unit 30 so as to be able to perform the convex scan. Is configured. On the other
hand, as shown in FIG. 19 (b), the ultrasonic endoscope 2H of the present embodiment is in the
circumferential direction of the distal end portion of the insertion portion so that radial scanning
in the direction orthogonal to the endoscope insertion direction is possible. A band-shaped cMUT 92 is arranged.
[0096]
As shown in FIG. 20A, the strip-shaped c-MUT 92 has a plurality of c-MUT chips 94 arranged in a
chip shape by arranging a plurality of c-MUT cells on a flexible flat substrate 93 at a
predetermined interval. , Mounted and configured. The strip-shaped c-MUT 92 is deformed into a
predetermined shape as shown in FIG. 20B by mounting and arranging a plurality of c-MUT chips
94 at predetermined intervals. Therefore, by disposing the strip c-MUT 92 in the circumferential
direction at the distal end of the insertion portion, an ultrasound endoscope 2 H capable of
obtaining an ultrasound tomographic image by radial scanning is configured.
[0097]
On the other hand, as shown in FIG. 20C, the curved surface c-MUT 91 is configured by
mounting and arranging a plurality of c-MUT chips 94 at predetermined intervals on a curved
substrate 95 formed in a predetermined curved shape. By disposing this curved surface shape cMUT 91 at the tip of the ultrasonic observation unit 30, an ultrasonic endoscope 2G capable of
obtaining an ultrasonic tomographic image by convex scan is configured.
[0098]
A curved surface having a predetermined shape is formed in advance at the tip of the ultrasonic
observation unit 30, and a band-shaped c-MUT 92 configured to be deformed into the
predetermined shape is disposed on this curved surface, and an ultrasonic tomographic image by
convex scan The ultrasound endoscope 2G may be configured to obtain
[0099]
Further, as shown by a broken line on the proximal end side of the ultrasonic observation unit 30
of the ultrasonic endoscope 2G, a band c-MUT 92 is disposed to constitute a biplane type
ultrasonic endoscope. Good.
04-05-2019
28
[0100]
Another configuration example of the c-MUT cell will be described with reference to FIG.
As shown in the figure, in the c-MUT cell 100 according to the present embodiment, in the air
gap 40 formed between the upper electrode 37 u and the lower electrode 37 d constituting the
capacitor portion, the c-MUT cell 100 has a high dielectric constant and a predetermined
thickness A dielectric film 101 is provided.
By this, it is possible to increase the capacitance of the capacitor section to enhance the
transmission / reception sensitivity.
[0101]
The porous processing of the c-MUT cell of FIG. 22 will be described. As shown in FIG. 22 (a), the
porous processing is performed on the membrane 38 to provide a porous acoustic matching
layer 117 whose acoustic impedance is as small as that of the resin material. The MUT cell 103
may be configured.
As shown in FIG. 22 (b), in the chemical conversion treatment step of the porous treatment, the
acoustic impedance largely changes depending on the treatment time. That is, since the acoustic
impedance strongly depends on the chemical conversion treatment time, the transmission /
reception sensitivity can be enhanced by controlling the chemical conversion treatment time to
provide the porous acoustic matching layer 117.
[0102]
Another configuration example of the c-MUT cell will be described with reference to FIG. FIG. 23
(a) is a view showing the configuration of a conventional c-MUT cell, and FIG. 23 (b) is a view
showing the configuration of a c-MUT cell characterized on the upper surface of the substrate.
04-05-2019
29
[0103]
As shown in FIG. 23A, in the conventional c-MUT cell 250, since the air gap 40 is formed in
vacuum, it is provided on the membrane 38 when it is left in the air after the c-MUT is formed.
The upper electrode 37u was bent and deformed. In the present embodiment, as shown in FIG.
23B, a predetermined concave surface 110 based on the bending deformation is provided in
advance on the upper surface of the silicon substrate 35 to form a void 112 in the c-MUT cell
101. There is.
[0104]
As a result, the distance between the upper electrode 37u and the lower electrode 37d can be
formed uniformly and narrowly, the capacitance of the capacitor portion can be increased, and
the transmission / reception sensitivity can be enhanced.
[0105]
It is to be noted that as shown in the other structural example of the c-MUT cell of FIG. 24, while
forming the concave and convex curved surface 113 on the surface of the silicon substrate 35
and providing the curved lower electrode 114, The area of the curved upper electrode 115 and
the curved lower electrode 114 is increased by configuring the upper electrode provided on the
membrane 38 disposed opposite to the curved surface as the curved upper electrode 115 that
substantially matches the uneven curved surface 113. Transmission / reception sensitivity can be
enhanced by increasing the capacitance of the capacitor unit of the MUT cell 102.
Reference numeral 116 denotes a curved air gap.
[0106]
Second Embodiment FIGS. 25 to 29 relate to a second embodiment of the present embodiment,
and FIG. 25 is a multifunctional super having a silicon light emitting element and a silicon light
receiving element provided on a silicon substrate in addition to a c-MUT. 26 illustrates an
example of the cross-sectional configuration of a multi-function ultrasonic transducer, and FIG.
27 illustrates a multi-functional ultra-high-performance ultrasonic transducer in which a silicon
light emitting element and a silicon light receiving element are disposed. FIG. 28 is a view for
explaining another configuration example of the sound wave transducer, FIG. 28 is a view for
further describing the configuration of the multi-function ultrasonic transducer having the micro
04-05-2019
30
gyro sensor disposed therein, and FIG. It is a figure explaining the composition of a multifunction
ultrasonic transducer.
[0107]
FIG. 27 (a) is a view for explaining the configuration of a multi-function ultrasonic transducer
having different outer shapes, and FIG. 27 (b) is another arrangement example when the silicon
light emitting element and the silicon light receiving element are arranged at the central portion.
FIG. 27 (c) shows another arrangement when the silicon light emitting element and the silicon
light receiving element are arranged outside, and FIG. 29 (a) is provided with a dummy c-MUT
cell for capacitance measurement. FIG. 29 (b) is a flowchart illustrating the operation and
function of the dummy c-MUT cell.
[0108]
As shown in FIG. 25, in the ultrasonic endoscope 120 of the present embodiment, a
multifunctional ultrasonic transducer 122 is disposed on the distal end surface 121 a of the
insertion portion 121.
In this multi-functional ultrasonic transducer 122, c-MUT 131 in which the opening shape of the
ultrasonic scanning surface formed by using silicon micromachining technology is formed in a
ring shape, and the position substantially in the center of this ring c-MUT 131 A light emitting
unit 123 formed of a silicon light emitting element and a light receiving unit 124 formed of a
silicon light receiving element are juxtaposed on the same surface.
[0109]
As shown in FIG. 26, in the c-MUT 131 of the present embodiment, for example, the first
intermediate dielectric layer 41 and the second intermediate dielectric layer 42 are formed on
the silicon substrate 35 in which a plurality of c-MUT cells 131a are arrayed. And various control
circuits 43a for controlling the light emitting unit 123 and the light receiving unit 124
configured of a c-MOS integrated circuit that performs the predetermined control in addition to
the access circuit forming unit in the dielectric layers 41 and 42; 43b, 43c,... And wiring
electrodes 44a, 44b, 44c, 44d,.
[0110]
The lower electrode 37d and the wiring electrode 44a, the wiring electrode 44a and the wiring
04-05-2019
31
electrode 44b, the wiring electrode 44b and the wiring electrode 44c, the wiring electrode 44c
and the control circuit 43c, the wiring electrode 44d and the control circuit 43b, the wiring
electrode 44d and the control circuit 43c, etc. Are electrically connected by via holes 45,
respectively.
[0111]
An electric cable (not shown) extends from the light emitting unit 123 and the light receiving
unit 124 and is electrically connected to the endoscope observation device 3.
Therefore, in the ultrasonic endoscope apparatus 1 of the present embodiment, a lamp for
emitting illumination light as a light source unit is not necessary for the endoscope observation
apparatus, and a light guide fiber for transmitting the illumination light to the ultrasonic
endoscope 120 Is no longer needed.
[0112]
As shown by the broken line in the figure, a through hole 125 for a forceps outlet may be formed
at a predetermined position of the multi-function ultrasonic transducer 122.
Further, the light emitting unit 123 is, for example, a light emitting diode or a laser diode, and
the light receiving unit 124 is, for example, any one of a C-MOS and a CCD.
The other configuration is the same as that of the first embodiment, and the same reference
numerals are given to the same members and the description will be omitted. Reference numeral
126 is a buffer area.
[0113]
In this embodiment, the c-MUT 131 of the multi-functional ultrasonic transducer 122 is formed
in a ring shape, and the light emitting unit 123 and the light receiving unit 124 disposed in the
center are formed in a circular shape. The c-MUT shape of the multi-function ultrasonic
transducer and the shapes and arrangement positions of the illumination unit and the light
receiving unit are not limited to these, and for example, as shown in FIG. The square light
04-05-2019
32
emitting unit 123 may be provided at the center of the MUT 131 and the square multifunctional
ultrasonic transducer 127 may be formed at the four corners of the c-MUT 131.
[0114]
Further, as shown in FIG. 27B, a polygonal light receiving portion 124 is provided at the center of
the ring-shaped c-MUT 131, and a plurality of polygonal light emitting portions 123 are provided
around this polygonal light receiving portion 124. A multi-function ultrasound transducer 128
may be formed.
[0115]
Further, as shown in FIG. 27C, a circular c-MUT 31 is formed, and for example, a polygonal light
emitting unit 123 and a light receiving unit 124 are regularly juxtaposed around the c-MUT 31
to form a multifunctional ultrasonic wave The transducer 129 may be formed.
[0116]
The operation of the ultrasonic endoscope 120 configured as described above will be described.
First, the observation site is illuminated by the light emitting unit 123 provided in the multifunction ultrasonic transducer 122 disposed on the tip end surface of the insertion unit 121 of
the ultrasonic endoscope 120, and the observation site illuminated by the light emitting unit 123
The endoscopic image of the subject is captured by the light receiving unit 124.
As a result, an endoscopic image is displayed on the screen of the monitor 5.
As a result, the operator inserts the insertion portion 121 into the body cavity while observing
the endoscopic image.
[0117]
Then, when the distal end of the insertion portion 121 is disposed in the vicinity of the target
observation site, for example, the distal end is submerged in water as an ultrasonic wave
transmission medium, and the ultrasonic observation device 4 is operated to perform multiple
functions. The c-MUT 131 of the ultrasonic transducer 122 is brought into a driven state.
04-05-2019
33
[0118]
Then, as described in the first embodiment, the CPU 51 of the ultrasonic observation apparatus 4
outputs an operation instruction signal corresponding to the operation instruction of the
observer to the c-MUT 131.
Then, the c-MUT cell 131a is switched to the transmission state / reception state to emit an
ultrasonic wave, and the reflected ultrasonic wave is received to display an ultrasonic
tomographic image on the screen of the monitor 5. This enables ultrasonic observation of the
target observation site.
[0119]
Thus, an ultrasonic endoscope is configured by arranging a multi-functional ultrasonic
transducer in which the illumination unit and the light receiving unit are formed using silicon
micromachining technology in addition to the c-MUT on the distal end surface of the insertion
unit. Thus, the ultrasonic endoscope can be configured without providing the observation optical
unit and the illumination optical unit in the ultrasonic endoscope.
[0120]
This realizes the reduction in diameter and the reduction in size of the ultrasonic endoscope.
[0121]
In addition, the opening shape of the ultrasonic transducer can be set to a desired shape and size
by appropriately setting the arrangement of c-MUT cells, and the shape, size, and number of the
illumination unit and the light receiving unit are appropriately set. By creating a multi-functional
ultrasonic transducer, the degree of freedom in design of the ultrasonic endoscope is increased,
such as downsizing and high precision.
The other actions and effects are similar to those of the first embodiment.
04-05-2019
34
[0122]
Here, a modified example of the multifunctional ultrasonic transducer will be described with
reference to FIGS. 28 and 29.
In the multifunctional ultrasonic transducer 132 shown in FIG. 28, in addition to the c-MUT 131,
the light emitting unit 123 and the light receiving unit 124, the position detection is performed
by detecting the movement of the distal end of the ultrasonic endoscope. Electrostatic micro gyro
sensors 133 and 134 arranged to correspond to the Y direction are provided side by side.
[0123]
As a result, the position detection signals output from the electrostatic micro gyro sensors 133
and 134 are arithmetically processed by an arithmetic unit (not shown) to quantitatively grasp
the position of the tip of the ultrasonic endoscope at all times. be able to.
[0124]
In the multi-function ultrasonic transducer 135 shown in FIG. 29A, a plurality of c-MUT cells at
arbitrary positions constituting the c-MUT 131 are used as the capacitance measurement cell
136.
Then, based on the electric signal output from the capacitance measuring cell 136, the ultrasonic
drive signal is corrected and output.
[0125]
That is, when an instruction for measuring the capacitance is output by the ultrasonic
observation device 4, data at the time of operation is sequentially output from each of the
capacitance measuring cells as shown in step S1 of FIG. 29 (b). It is input to the capacitance
measurement correction unit. Then, in the capacitance measurement / correction unit, after
calculating the average value of the input data as shown in step S2, the process proceeds to step
S3 to compare this calculated value with a preset reference value. Then, the difference is
evaluated and the process proceeds to step S4. In step S4, the c-MUT drive signal is corrected
04-05-2019
35
based on the evaluation result in step S3. As a result, the corrected ultrasonic drive signal is
output to the c-MUT cell.
[0126]
As described above, by providing a part of the c-MUT cell configuring the c-MUT as a capacitance
measurement cell, the ultrasonic drive is always optimally corrected in the c-MUT cell
configuring the c-MUT cell A signal can be output to obtain an ultrasound diagnostic image.
[0127]
The present invention is not limited to the embodiment described above, and various
modifications can be made without departing from the scope of the invention.
[0128]
[Appendix] According to the embodiment of the present invention as described above, the
following configuration can be obtained.
[0129]
(1) An ultrasonic endoscope for obtaining biological tissue information by transmitting and
receiving ultrasonic waves with an ultrasonic transducer inserted into a body cavity, and a signal
of an electrical signal related to biological tissue information transmitted from the ultrasonic
endoscope An ultrasonic endoscope apparatus comprising an ultrasonic observation apparatus
that performs processing and drive control of the ultrasonic transducer, wherein the ultrasonic
transducer mounted on the ultrasonic endoscope is formed of a silicon semiconductor substrate
Endoscope device.
[0130]
(2) The ultrasonic endoscope apparatus according to appendix 1, wherein the ultrasonic
transducer is an electrostatic ultrasonic transducer processed using silicon micromachining
technology.
[0131]
(3) The ultrasonic endoscope apparatus according to Appendix 2, wherein the electrostatic
ultrasonic transducer is an array structure in which a large number of ultrasonic transducer
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elements are linearly arranged.
The ultrasonic endoscope apparatus according to appendix 2, wherein the electrostatic ultrasonic
transducer has an array structure in which a large number of ultrasonic transducer elements are
two-dimensionally arranged.
[0132]
(5) The ultrasonic endoscope apparatus according to Appendix 2, wherein the electrostatic
ultrasonic transducer has an array structure in which a large number of ultrasonic transducer
elements are arranged in a ring shape.
[0133]
(6) The ultrasonic endoscope apparatus according to any one of supplementary notes 3 to 5,
wherein the ultrasonic transducer elements are distributed based on a predetermined rule to
form a predetermined aperture shape.
[0134]
(7) The ultrasonic endoscope apparatus according to any one of Appendixes 3 to 5, wherein the
ultrasonic transducer elements have different functions, and are arranged in at least two groups.
(8) The groups are arranged separately. The ultrasound endoscope apparatus according to
appendix 7.
[0135]
(9) The ultrasonic endoscope apparatus according to appendix 7, wherein the groups are further
subdivided to form subdivided groups, and the subdivided groups are alternately arranged.
[0136]
(10) The ultrasonic endoscope apparatus according to appendix 7, wherein the groups are
formed by alternately arranging the ultrasonic transducer elements constituting the groups.
[0137]
(11) The ultrasonic endoscope apparatus according to appendix 7, wherein at least one of the
groups has a function of transmitting an ultrasonic wave, and at least one other group has a
function of receiving an ultrasonic wave. .
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[0138]
(12) The ultrasonic endoscope apparatus according to appendix 5, wherein through holes are
formed in the arrayed ultrasonic transducers arranged in the ring shape.
[0139]
(13) The ultrasonic endoscope apparatus according to appendix 12, wherein the through hole is
configured as a forceps outlet communicating with the treatment instrument channel.
[0140]
(14) The ultrasound endoscope according to appendix 2, wherein a dielectric film having a high
dielectric constant is formed in an air gap portion which constitutes a capacitor portion by the
upper electrode and the lower electrode which constitute the electrostatic ultrasonic transducer.
apparatus.
[0141]
(15) The ultrasonic endoscope apparatus according to appendix 2, wherein an uneven surface is
formed on the surface of a substrate constituting the electrostatic ultrasonic transducer.
[0142]
(16) The ultrasonic endoscope apparatus according to appendix 4, wherein the two-dimensional
array ultrasonic transducer is disposed on a curved surface portion of the ultrasonic endoscope.
[0143]
(17) The ultrasonic endoscope apparatus according to appendix 16, wherein the two-dimensional
array ultrasonic transducer is circumferentially arranged in the ultrasonic endoscope insertion
portion.
[0144]
(18) The ultrasonic endoscope apparatus according to appendix 2, wherein the ultrasonic
transducer is configured as a chip ultrasonic transducer, and the chip ultrasonic transducer is
mounted on a substrate.
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[0145]
(19) The ultrasonic endoscope apparatus according to appendix 18, wherein the substrate is a
flat substrate having flexibility.
[0146]
(20) The ultrasonic endoscope apparatus according to appendix 18, wherein the substrate is a
curved substrate formed in a predetermined curved shape.
[0147]
Reference Signs List 2 ultrasound endoscope 30 ultrasound observation unit 31 electrostatic
ultrasonic transducer (c-MUT) 31a c-MUT cell 35 silicon substrate 37 d lower electrode 37 u
upper electrode 38 silicon membrane 40 Vacuum gap 44 ... Wiring electrode
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