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JP2009071395

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DESCRIPTION JP2009071395
PROBLEM TO BE SOLVED: To provide an ultrasonic receiving element suitable for downsizing
and having a good receiving sensitivity as compared with an ultrasonic receiving element made
of a piezoelectric ceramic material, and an ultrasonic transducer using the same. SOLUTION: An
ultrasonic wave receiving element 1 according to the present invention comprises: a diaphragm 2
made of a semiconductor having a thin film membrane portion 8; and semiconductor
piezoresistive elements R, R, R provided on the membrane portion 8 of the diaphragm 2. , R, and
a resonance frequency adjustment mechanism 5 for adjusting the resonance frequency of the
diaphragm 2 to the frequency of the reception ultrasonic wave. In the ultrasonic transducer 13
according to the present invention, an ultrasonic transmitting element 15 for transmitting an
ultrasonic wave using the piezoelectric effect of a piezoelectric material and the ultrasonic
receiving element 1 are provided on a semiconductor substrate 14. It is [Selected figure] Figure 2
Ultrasonic receiving element and ultrasonic transducer using the same
[0001]
The present invention relates to an ultrasonic receiving element that receives ultrasonic waves
and detects the sound pressure, and an ultrasonic transducer using the same, and more
particularly to a diaphragm in which a piezoresistive element is arranged, and a resonance
frequency of the diaphragm The present invention relates to an ultrasonic receiving element
provided with a resonant frequency adjustment mechanism for adjusting to the frequency of a
sound wave, and an ultrasonic transducer using the same.
[0002]
04-05-2019
1
In medical ultrasonic diagnosis, an abnormal tissue is detected by transmitting an ultrasonic
wave generated by a probe into the body and receiving an ultrasonic wave reflected by a cancer
or the like in the body by the probe.
In particular, when diagnosing a small initial cancer or the like in the deep part of an organ, if the
abnormal tissue is small, the reflected signal is small, and the reflected signal from the deep part
is large in attenuation during propagation. It becomes. Here, the probe is a so-called ultrasonic
transducer, which has both an ultrasonic wave transmitting function and a ultrasonic wave
transmitting function. A conventional transducer is provided with a single element made of a
piezoelectric ceramic material, and by switching this element in time, it has doubled as an
ultrasonic transmitting element for transmission and an ultrasonic receiving element for
receiving (for example, Patent Document 1). That is, when an alternating voltage is applied to the
element, the element is distorted by the piezoelectric effect to generate an ultrasonic wave. On
the other hand, when the element is irradiated with an ultrasonic wave, the element is similarly
distorted due to the piezoelectric effect to generate an AC voltage. Therefore, the sound pressure
of the ultrasonic wave can be detected by detecting this AC voltage.
[0003]
Unexamined-Japanese-Patent No. 08-168097 gazette
[0004]
However, there is a problem that conventional ultrasonic transducers are not suitable for
miniaturization.
More specifically, in the conventional ultrasonic transducer, it is difficult to miniaturize the
element because microfabrication of the piezoelectric ceramic material that constitutes the
element is difficult. In addition, the piezoelectric ceramic material can secure relatively large
transmission output even if it is miniaturized, so it is suitable for constructing an ultrasonic
transmission element, but if it is miniaturized, the reception sensitivity is deteriorated. Not
suitable for configuration. That is, when the element is miniaturized and the reception area is
reduced, the capacitance of the element is reduced in proportion to this. As a result, the
impedance of the circuit including the element is increased to make it impossible to obtain a
sufficient S / N ratio, and as a result, high sensitivity can not be obtained.
04-05-2019
2
[0005]
The present invention has been made in view of such problems, and uses an ultrasonic receiving
element suitable for downsizing and having a good receiving sensitivity as compared with an
ultrasonic receiving element made of a piezoelectric ceramic material, and the same. Provided is
an ultrasonic transducer.
[0006]
An ultrasonic receiving element according to the present invention for achieving the above object
is an ultrasonic receiving element for receiving an ultrasonic wave and detecting its sound
pressure, comprising: a diaphragm made of a semiconductor having a membrane part in the form
of a thin film; A sound pressure detection circuit for detecting the sound pressure of the received
ultrasonic wave from a change in resistance value of the semiconductor piezoresistive element
provided in the membrane portion of the above, a resonant frequency adjustment mechanism for
adjusting the resonant frequency of the diaphragm to the frequency of the received ultrasound;
The
[0007]
Further, in the ultrasonic receiving element according to the present invention, the resonant
frequency adjusting mechanism is provided with a counter electrode provided to face the
membrane portion at a predetermined distance, and a direct current between the counter
electrode and the membrane portion. And a DC bias power supply for applying a bias voltage.
[0008]
Further, in the ultrasonic receiving element according to the present invention, an insulator is
interposed between a portion other than the membrane portion of the diaphragm and the
counter electrode, and the insulator is surrounded by the insulator, the membrane portion, and
the counter electrode. The space is depressurized lower than the external pressure.
[0009]
Further, in the ultrasonic receiving element according to the present invention, an insulator is
interposed between a portion of the diaphragm other than the membrane portion and the
counter electrode, and the insulation is provided in at least one of the membrane portion and the
counter electrode. A communication hole is formed to communicate a space surrounded by the
body, the membrane portion, and the counter electrode with the outside.
04-05-2019
3
[0010]
In the ultrasonic transducer according to the present invention, an ultrasonic wave transmitting
element for transmitting an ultrasonic wave using a piezoelectric effect of a piezoelectric material
on a semiconductor substrate, and an ultrasonic wave transmitted from the ultrasonic wave
transmitting element are received. The ultrasonic wave receiving element according to any one of
claims 1 to 4, which detects the sound pressure of the rat, is provided.
[0011]
The ultrasonic transducer according to the present invention is characterized in that the
piezoelectric transmitting element is a bulk material.
[0012]
In the ultrasonic transducer according to the present invention, in the ultrasonic transmitting
element, the piezoelectric material is a thin film material.
[0013]
In the ultrasonic transducer according to the present invention, the area ratio of the ultrasonic
transmitting element in the entire semiconductor substrate is larger than the area ratio of the
ultrasonic receiving element in the entire semiconductor substrate.
[0014]
In the ultrasonic transducer according to the present invention, at least one of the ultrasonic
transmitting element and the ultrasonic receiving element is provided in an array.
[0015]
According to the ultrasonic wave receiving element according to the present invention, the
semiconductor piezoresistive element provided on the diaphragm is easy to microfabricate, so it
is suitable for miniaturizing the ultrasonic wave receiving element.
Further, the sound pressure detection circuit that detects the change in resistance value of the
semiconductor piezoresistive element has a low impedance, so that it is possible to manufacture
an ultrasonic wave receiving element having a high S / N ratio and high reception sensitivity.
04-05-2019
4
Furthermore, by providing the resonance frequency adjustment mechanism, the reception
sensitivity of the ultrasonic wave receiving element can be further enhanced.
[0016]
Further, according to the ultrasonic receiving element according to the present invention, when a
DC bias voltage is applied between the membrane part and the counter electrode, distortion
occurs in the membrane part and the resonance frequency of the diaphragm changes.
Thus, the resonance frequency of the diaphragm can be easily adjusted by the simple
configuration.
[0017]
Further, according to the ultrasonic receiving element according to the present invention, since
the space surrounded by the insulator, the membrane portion and the counter electrode is
decompressed lower than the external pressure, the membrane portion is hindered by the air in
the space. Can be deformed freely.
As a result, the membrane portion sufficiently responds to the sound pressure of the ultrasonic
wave, so that accurate sound pressure detection becomes possible.
[0018]
Further, according to the ultrasonic receiving element according to the present invention, the air
in the space surrounded by the insulator, the membrane portion and the counter electrode can
freely travel between the outside through the communication hole, so that the membrane portion
Can be deformed freely without being disturbed by the air in the space.
As a result, the membrane portion sufficiently responds to the sound pressure of the ultrasonic
04-05-2019
5
wave, so that accurate sound pressure detection becomes possible.
[0019]
Further, according to the ultrasonic transducer in accordance with the present invention, since
the piezoelectric transmitting element is adopted as the ultrasonic transmitting element, a
relatively large transmission output can be secured even if the element is miniaturized.
On the other hand, since the piezoresistive type is adopted as the ultrasonic wave receiving
element, it is easy to miniaturize the element, and high reception sensitivity can be secured even
if the element is miniaturized.
As described above, the ultrasonic transducer as a whole can be made compact and highly
sensitive.
[0020]
Moreover, according to the ultrasonic transducer concerning the present invention, since the
piezoelectric material which constitutes an ultrasonic transmitting element is bulk material, high
transmission output can be obtained.
[0021]
Further, according to the ultrasonic transducer according to the present invention, since the
piezoelectric material constituting the ultrasonic transmitting element is a thin film material, it
can be manufactured on a semiconductor substrate in a semiconductor process.
Therefore, integration of the ultrasonic wave receiving element is facilitated.
[0022]
Further, according to the ultrasonic transducer according to the present invention, a large
04-05-2019
6
transmission output can be obtained as the area ratio of the ultrasonic transmitting element is
large, while securing high reception sensitivity even if the area ratio of the ultrasonic receiving
element is small. Can.
As a result, a compact and highly sensitive ultrasonic transducer can be realized.
[0023]
Further, according to the ultrasonic transducer according to the present invention, at least one of
the ultrasonic transmitting element and the ultrasonic receiving element is provided in the form
of an array, so that each element constituting the array is sequentially switched. Or, by using a
phased array method, two-dimensional location information of an object can be obtained and
imaged.
[0024]
First, the configuration of an ultrasonic wave receiving element according to an embodiment of
the present invention will be described based on the drawings.
FIGS. 1 and 2 are views showing an ultrasonic wave receiving element 1 according to the present
embodiment, FIG. 1 is a schematic plan view, and FIG. 2 is a schematic vertical sectional view
showing an AA cross section in FIG.
The ultrasonic wave receiving element 1 includes a diaphragm 2 for receiving ultrasonic waves, a
support 3 supporting the diaphragm 2 from below, an insulator 4 interposed between the
diaphragm 2 and the support 3, and a diaphragm 2. A sound pressure detection circuit (not
shown in FIGS. 1 and 2) for detecting the sound pressure of the ultrasonic wave received by the
device; a resonance frequency adjustment mechanism 5 for adjusting the resonance frequency of
the diaphragm 2 to the frequency of the reception ultrasonic wave; Is provided.
The ultrasonic wave receiving element 1 can detect an elastic wave, so-called acoustic emission,
which is generated when a crack is generated or a crack develops in a material, and is used, for
example, for material evaluation or maintenance inspection of a structure. Used for
04-05-2019
7
[0025]
The support 3 plays a role of supporting the diaphragm 2 from below and a role of a counter
electrode of the diaphragm 2. The support 3 is a plate-like member made of silicon and has a
substantially rectangular shape in a plan view, and its thickness is, for example, about 300 to
500 μm. Then, a communication hole 6 having a substantially circular cross-sectional shape is
formed so as to reach the bottom surface from the top surface through the central portion of the
support 3. The number of communicating holes 6 and the cross-sectional shape can be arbitrarily
changed in design. Moreover, if the material of the support body 3 can be used as a counter
electrode, it is also possible to use semiconductors other than silicon and other conductive
members.
[0026]
The insulator 4 is for electrically isolating the diaphragm 2 and the support 3. The insulator 4 is
a plate-like member made of silicon dioxide, and as shown in FIGS. 1 and 2, the shape in plan
view of the insulator 4 is substantially the same as that of the support 3. Moreover, although
illustrated typically in FIG. 2, the actual thickness of the insulator 4 is much thinner than the
support body 3, for example, is about 1-3 micrometers. Then, a through hole 7 having a
substantially rectangular cross-sectional shape is formed through the central portion of the
insulator 4. The insulator 4 configured in this manner is placed on the support 3 so that the
outer edge position thereof is aligned with the outer edge position of the support 3, and the
bottom surface thereof is fixed to the upper surface of the support 3. At this time, the lower
opening of the through hole 7 of the insulator 4 and the upper opening of the communication
hole 6 of the support 3 are in communication with each other. The cross-sectional shape of the
through hole 7 can be arbitrarily changed in design. For example, as shown in FIG. 3, it is also
possible to form the cross-sectional shape in a circular shape. In this case, the symmetry of the
membrane portion described later is good, and the so-called Q value is large. Therefore, the
reception sensitivity can be made higher than in the case where the cross-sectional shape is
rectangular. Further, the material of the insulator 4 may be another non-conductive member, and
the shape in plan view of the insulator 4 can be appropriately changed in design according to the
shape of the support 3.
[0027]
The diaphragm 2 is for converting a sound pressure change of ultrasonic waves into a voltage
04-05-2019
8
change and detecting it. The diaphragm 2 is a thin film-like member made of silicon, and its
shape in plan view is a rectangular shape substantially equal to that of the support 3 and the
insulator 4. The diaphragm 2 configured in this way is placed on the insulator 4 with its outer
edge position aligned with the outer edge position of the insulator 4 as shown in FIG. 2, and its
bottom surface is fixed to the insulator 4 Be done. At this time, a membrane portion 8 which can
be freely deformed without being fixed to the insulator 4 is formed at a position immediately
above the through hole 7 in the diaphragm 2. The shape of the diaphragm 2 in plan view can be
appropriately changed in design according to the shape of the insulator 4.
[0028]
The sound pressure detection circuit is for detecting the sound pressure of the received
ultrasonic wave from the magnitude of distortion generated in the membrane unit 8. FIG. 4 is a
schematic view showing the configuration of the sound pressure detection circuit 9. The sound
pressure detection circuit 9 is configured as a full bridge circuit including four semiconductor
piezoresistive elements R1, R2, R3, and R4. The semiconductor piezoresistive elements R1, R2,
R3 and R4 are formed on the surface of the membrane portion 8 made of silicon by a
semiconductor process. The four semiconductor piezoresistive elements R1, R2, R3 and R4 are
respectively provided at the outermost position of the membrane portion 8 of the diaphragm 2
as shown in FIG. 1, and two semiconductor piezoresistive elements R1 and R2 among them are
provided. The two semiconductor piezoresistive elements R3 and R4 are provided opposite to
each other at a predetermined interval in the direction orthogonal to the other while being
provided to oppose each other at a predetermined interval across the center position of the
diaphragm 2 There is. According to such a sound pressure detection circuit 9, when the balance
of the entire circuit is broken due to a change in resistance value of each of the semiconductor
piezoresistive elements R1, R2, R3 and R4, an output voltage as an unbalanced voltage is
detected. It is possible to detect the sound pressure of the received ultrasonic wave by the
magnitude of this output voltage. The number and arrangement position of the semiconductor
piezoresistive elements R1, R2, R3 and R4 are not limited to the present embodiment, and design
changes can be made as appropriate within the range in which the bridge circuit can be formed.
[0029]
The resonance frequency adjustment mechanism 5 is for enhancing the reception sensitivity of
the ultrasonic wave receiving element 1 by matching the resonance frequency of the diaphragm
2 to the frequency of the reception ultrasonic wave. As shown in FIG. 2, this resonance frequency
adjusting mechanism 5 is configured to include a DC bias power supply 10, and one end side
04-05-2019
9
thereof is electrically connected to the diaphragm 2 and the other end side is electrically
connected to the support 3 as a counter electrode. There is. According to the resonance
frequency adjusting mechanism 5 configured as described above, the DC bias voltage is applied
between the diaphragm 2 and the support 3 to generate distortion in the membrane portion 8 of
the diaphragm 2. The resonant frequency can be adjusted to any size.
[0030]
According to the ultrasonic wave receiving element 1 configured as described above, the
semiconductor piezoresistive elements R1, R2, R3 and R4 provided in the membrane portion 8
can be easily microfabricated, so that the ultrasonic wave receiving element 1 can be
miniaturized. Is suitable. In the method of detecting the sound pressure of ultrasonic waves using
the piezoresistance effect, the S / N ratio is high because the impedance of the sound pressure
detection circuit 9 is low. As a result, it is possible to manufacture the compact ultrasonic
receiving element 1 with high receiving sensitivity.
[0031]
Next, the operation of the ultrasonic wave receiving element 1 will be described. When the
diaphragm 2 receives an ultrasonic wave, the membrane portion 8 which has received the sound
pressure of the ultrasonic wave tries to deform so as to expand toward the insulator 4 side. Here,
as described above, the space 11 surrounded by the membrane portion 8, the insulator 4 and the
support 3 is in communication with the outside 12 through the communication hole 6, so the air
in the space 11 is the membrane portion When pressure is received from 8, it is possible to
freely move back and forth between the outside 12. Thereby, the membrane part 8 which
received the sound pressure of the ultrasonic wave can be freely deformed without being blocked
by the air in the space 11. Then, when distortion occurs in the membrane unit 8, the resistance
values of the four semiconductor piezoresistive elements R1, R2, R3, and R4 provided in the
membrane unit 8 change, and the sound pressure detection circuit 9 generates the sound of the
received ultrasonic wave. Pressure is detected. In addition, the resonance frequency adjustment
mechanism 5 adjusts the resonance frequency of the diaphragm 2 to the frequency of the
receiving ultrasonic wave, so that the sensitivity of the ultrasonic wave receiving element 1 can
be increased.
[0032]
04-05-2019
10
In the present embodiment, in order to communicate the space 11 surrounded by the membrane
portion 8, the insulator 4 and the support 3 to the outside 12, the communication hole 6 is
formed in the support 3, but the present invention is limited thereto Although not shown in detail
in the figure, the support 3 may have the communication hole 6 in the membrane portion 8
without providing the communication hole 6, or the communication hole 6 may be provided in
both the support 3 and the membrane portion 8. You may provide. Further, as means for causing
the membrane portion 8 to sufficiently respond to the sound pressure of the ultrasonic wave, the
inside of the space 11 is formed using a pump (not shown) etc. other than forming the
communication hole 6 communicating the space 11 with the outside 12. It is also possible to
depressurize.
[0033]
Next, an ultrasonic transducer using the ultrasonic receiving element 1 will be described. FIG. 5 is
a schematic perspective view showing an ultrasonic transducer 13 according to the present
embodiment. In FIG. 5, for convenience of explanation, a part is shown in a broken state. The
ultrasonic transducer 13 comprises an ultrasonic transmitting element 15 for transmitting an
ultrasonic wave on a substantially circular semiconductor substrate 14 in plan view, and an
ultrasonic wave emitted from the ultrasonic transmitting element 15 and reflected by an object.
And an ultrasonic wave receiving element 16 for receiving the signals.
[0034]
The ultrasonic wave receiving element 16 is not shown in detail in FIG. 5, but has the same
configuration as the ultrasonic wave receiving element 1 shown in FIG. 1 and FIG. The ultrasonic
receiving element 16 is a circle having a diameter smaller than that of the semiconductor
substrate 14 in plan view, and is provided on the upper surface of the semiconductor substrate
14 so that the center position thereof matches the center position of the semiconductor substrate
14.
[0035]
The ultrasonic transmitting element 15 is a conventional one that generates an ultrasonic wave
using the piezoelectric effect of a piezoelectric material. As shown in FIG. 5, the ultrasonic
04-05-2019
11
transmitting element 15 has a substantially donut shape in a plan view, and the outer diameter is
approximately the same as that of the semiconductor substrate 14, and the inner diameter is
slightly smaller than that of the ultrasonic receiving element 16. It has a large diameter. The
ultrasonic transmitting element 15 configured as described above is provided on the upper
surface of the semiconductor substrate 14 so as to surround the ultrasonic receiving element 16.
The material of the piezoelectric material constituting the ultrasonic wave transmitting element
15 is so-called PZT [abbreviated form of Pb (Zr, Ti) O3] or so-called PMN-PT [Pb (Zn1 / 3Nb2 /
3) O3-PbTiO3]. Abbreviated form] can be used. The piezoelectric material may be formed as a
bulk material or as a thin film material. When formed as a bulk material, there is an advantage
that a large transmission power can be obtained. On the other hand, when forming it as a thin
film material, it can manufacture on semiconductor substrate 14 in a semiconductor process by
conventionally publicly known sputtering method, sol gel method, CVD method, etc. Therefore,
the integration of the ultrasonic transmitting element 15 is facilitated as compared with the case
where the piezoelectric material needs to be fixed on the semiconductor substrate 14 when
formed as a bulk material.
[0036]
The shape of the semiconductor substrate 14 is not limited to a circle in plan view, and may be
formed, for example, in a rectangle in plan view, and the shapes of the ultrasonic transmitting
element 15 and the ultrasonic receiving element 16 may be correspondingly correspondingly.
Design changes can be made as appropriate.
[0037]
As described above, in the ultrasonic transducer 13, the ultrasonic transmitting element 15
adopts a piezoelectric type that can obtain relatively large transmission output even if it is
miniaturized, while the ultrasonic receiving element 16 is miniaturized. The piezoresistive
method is adopted which can obtain higher reception sensitivity than the piezoelectric method.
Thus, a compact and highly sensitive ultrasonic transducer 13 can be realized.
[0038]
Further, even if the ultrasonic wave receiving element 16 is miniaturized to reduce the receiving
area, relatively high receiving sensitivity can be obtained, while the ultrasonic wave transmitting
04-05-2019
12
element 15 secures a larger transmission output when the transmitting area is increased. be able
to. Therefore, as the area ratio of the ultrasonic wave transmitting element 15 to the ultrasonic
wave receiving element 16 on the semiconductor substrate 14, the reception area of the
ultrasonic wave receiving element 16 is made as small as possible, and the transmission area of
the ultrasonic wave transmitting element 15 is increased accordingly It is preferable to make it
as large as possible.
[0039]
Here, FIG. 6 shows an arrangement example different from that shown in FIG. 5 regarding the
arrangement of the ultrasonic transmission element 15 and the ultrasonic reception element 16
which constitute the ultrasonic transducer 13. In the arrangement example shown in FIG. 6A, the
ultrasonic transmitting element 15 circular in plan view is provided on the semiconductor
substrate 14 (not shown) circular in plan view so that the center position matches the
semiconductor substrate 14. The ring-shaped ultrasonic wave receiving element 16 is provided
in a plan view so as to surround this. Here, the ultrasonic transmitting element 15 is formed to be
slightly smaller in diameter than the semiconductor substrate 14, and the ultrasonic receiving
element 16 has an inner diameter slightly larger than the ultrasonic transmitting element 15 and
an outer diameter substantially equal to that of the semiconductor substrate 14. It is formed in
the same diameter. Further, in the arrangement example shown in FIG. 6B, the ring-shaped
ultrasonic wave receiving element 16 is planarly viewed on the semiconductor substrate 14 (not
shown) circular in plan view so that the center position matches the semiconductor substrate 14.
While being provided, the ring-shaped ultrasonic transmitting element 15 is provided in plan
view so as to surround it. Here, the outer diameter of the ultrasonic transmitting element 15 is
approximately the same as the diameter of the semiconductor substrate 14, and the inner
diameter is slightly larger than the outer diameter of the ultrasonic receiving element 16.
Further, in the arrangement example shown in FIG. 6C, the ultrasonic transmitting element 15
having a fan shape in a plan view and the ultrasonic receiving element 16 having a fan shape in a
plan view are formed on a semiconductor substrate 14 (not shown) having a circular shape in a
plan view. Are alternately provided at predetermined intervals in the circumferential direction of
the semiconductor substrate 14. Here, as described above, the ultrasonic transmitting element is
designed so that the receiving area of the ultrasonic receiving element 16 can be made as small
as possible, and the transmitting area of the ultrasonic transmitting element 15 can be made as
large as possible. The central angle of 15 is formed large, and the central angle of the ultrasonic
wave receiving element 16 is formed small. The way of arranging the ultrasonic transmitting
element 15 and the ultrasonic receiving apparatus is not limited to the example of arrangement
shown in FIG. 6, and design changes can be made as appropriate.
04-05-2019
13
[0040]
FIG. 7 is a view showing an arrangement example in which either or both of the ultrasonic
transmitting element 15 and the ultrasonic receiving element 16 are provided in an array. In the
present invention, “array-like” means that a plurality of ones are arranged adjacent to each
other. Here, in the arrangement example shown in FIG. 6A, the arrangement example shown in
FIG. 7A is obtained by dividing the ultrasonic wave receiving element 16 into a plurality of parts
in the circumferential direction. Not only the ultrasonic wave receiving element 16 but also the
ultrasonic wave transmitting element 15 can be divided into a plurality. Further, in the
arrangement example shown in FIG. 7B, in the arrangement example shown in FIG. 6B, both of
the ultrasonic wave transmitting element 15 and the ultrasonic wave receiving element 16 are
divided into a plurality of parts in the radial direction.
[0041]
As described above, when the ultrasonic wave transmitting element 15 and the ultrasonic wave
receiving element 16 are divided into a plurality of parts, the transmitting circuit for driving the
ultrasonic wave transmitting element 15 and the receiving circuit for driving the ultrasonic wave
receiving element 16 By sequentially switching and connecting to the sound wave transmitting
element 15 and the ultrasonic wave receiving element 16, two-dimensional location information
on the object can be obtained depending on whether or not the reflected sound from the object is
detected. Can be imaged. In addition, using a so-called phased array method, the order of driving
the individual ultrasonic wave transmitting elements 15 and the driving delay time are controlled
to generate an arbitrary ultrasonic beam, and the object is scanned with the generated ultrasonic
beam. Two-dimensional image information can be obtained.
[0042]
The ultrasonic transducer according to the present invention can be used not only for medical
applications but also for metal defect inspection and the like.
[0043]
FIG. 1 is a schematic plan view showing an ultrasound receiving element 1 according to an
embodiment of the present invention.
04-05-2019
14
The schematic longitudinal cross-sectional view which shows the AA cross section in FIG. The
schematic plan view which shows the ultrasonic receiving element 1 which concerns on the other
Example of this invention. FIG. 2 is a schematic view showing the configuration of a sound
pressure detection circuit 9; FIG. 1 is a schematic perspective view showing an ultrasonic
transducer 13 according to an embodiment of the present invention. FIG. 10 is a schematic plan
view showing another arrangement example of the ultrasonic transmitting element 15 and the
ultrasonic receiving element 16; FIG. 9 is a schematic plan view showing an arrangement
example in which either or both of the ultrasonic transmitting element 15 and the ultrasonic
receiving element 16 are provided in an array.
Explanation of sign
[0044]
1, 16 Ultrasonic wave receiving element 2 Diaphragm 3 Support (counter electrode) 4 Insulator
5 Resonant frequency adjustment mechanism 6 Communication hole 8 Membrane part 9 Sound
pressure detection circuit 10 DC bias power supply 11 Space 12 External 13 Ultrasonic
transducer 14 Semiconductor substrate 15 Ultrasonic Transmitter R1, R2, R3, R4 Semiconductor
Piezoresistor
04-05-2019
15
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