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DESCRIPTION JP2018042896

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DESCRIPTION JP2018042896
Abstract: To correct variation in electrical characteristics among a plurality of ultrasonic
transducers based on output values from a reference region. An ultrasonic probe includes a
plurality of ultrasonic transducers and a correction unit. An ultrasonic transducer is stacked on
the surface of a diaphragm, a lower electrode, and a lower electrode, and includes an effective
area that largely vibrates during piezoelectric conversion and a piezoelectric film including a
reference area that vibrates smaller during piezoelectric conversion than the effective area;
Including the electrode. The correction unit corrects the variation in performance among the
ultrasonic transducers. One or both of the lower electrode and the upper electrode includes an
effective area electrode portion independently connected to the effective area and a reference
area electrode portion independently connected to the reference area. The correction unit is a
device for correcting one or both of the output value from the effective area electrode unit and
the input value to the effective area electrode unit based on the output value from the reference
area electrode unit. [Selected figure] Figure 3
Ultrasonic probe and correction method of the ultrasonic probe
[0001]
The present invention relates to an ultrasound probe and a method of correcting the ultrasound
probe.
[0002]
The ultrasonic diagnostic apparatus transmits ultrasonic pulses from the ultrasonic probe into
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the subject, receives echo signals from the inside of the subject with the ultrasonic probe, and
converts the signals into electrical signals.
The ultrasonic probe has an ultrasonic transducer (ultrasonic transducer) that converts an
electrical signal into mechanical vibration or converts mechanical vibration into an electrical
signal. Since the thickness vibration is mainly used for the piezoelectric body used in the
ultrasonic probe of the conventional ultrasonic diagnostic apparatus, the thickness is about 1⁄4
of the wavelength, about 100 μm.
[0003]
In recent years, an ultrasonic transducer has been proposed which achieves miniaturization and
densification using semiconductor microfabrication technology (MEMS technology) (see, for
example, Non-Patent Document 1).
[0004]
The ultrasonic transducer described in Non-Patent Document 1 has a lower electrode, a
piezoelectric film stacked on the lower electrode, and an upper electrode stacked on the
piezoelectric film.
In the ultrasonic transducer described in Non-Patent Document 1, at the time of piezoelectric
conversion, there are a region with a high contribution to piezoelectric change (effective region)
and a region with a low contribution to piezoelectric change (reference region) It is known.
[0005]
Chao Wang, Zheyao Wang, Tian-Ling Ren, Senior Member, IEEE, Yiping Zhu, Yi Yang, Xiaoming
Wu, Haining Wang, Haijun Fang, and Litian Liu, "A Micromachined Piezoelectric Ultrasonic
Transducer Operating in d33 Mode Using Square Interdigital Electrodes" , IEEE SENSORS
JOURNAL, Vol.
7,
No. 7, pp. 967-976.
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[0006] However, since the piezoelectric material used for the ultrasonic transducer described in
Non-Patent Document 1 is a thin film and its thickness is 10 μm or less, it can be said that the
thickness is sufficient compared to the grain size. I want to. Thus, it is difficult to keep the
piezoelectric characteristics constant depending on the grain size and the distribution thereof. In
addition, it has been difficult to keep the electrical characteristics constant among the ultrasonic
transducers.
[0007] Therefore, a first object of the present invention is to provide an ultrasonic probe capable
of correcting the variation in electrical characteristics among a plurality of ultrasonic transducers
based on the output value from the reference region. A second object of the present invention is
to provide a method of correcting the ultrasonic probe.
[0008]
According to the present invention, as a means for solving the first problem described above, a
diaphragm, a lower electrode laminated on the surface of the diaphragm, and a surface of the
lower electrode laminated, it is effective to vibrate largely at the time of piezoelectric conversion
A plurality of ultrasonic transducers each including a piezoelectric film including a region and a
reference region that vibrates smaller at the time of piezoelectric conversion than the effective
region; and an upper electrode stacked on the surface of the piezoelectric film; A correction unit
for correcting performance variations among the transducers, one or both of the lower electrode
and the upper electrode are connected to an effective area electrode section independently; A
reference area electrode unit connected independently to a reference area, and the correction
unit is configured to output the reference area electrode unit from the effective area electrode
unit based on an output value from the reference area electrode unit. A device for correcting one
or both of the input value to the force value and the effective area electrode unit, to provide an
ultrasonic probe.
[0009]
Further, according to the present invention, as a means for solving the second problem described
above, a diaphragm, a lower electrode disposed on the diaphragm, a piezoelectric film disposed
on the lower electrode, and the piezoelectric An upper electrode disposed on the body film,
wherein the piezoelectric film includes an effective region which vibrates largely at the time of
piezoelectric conversion, and a reference region which vibrates smaller at the time of
piezoelectric conversion than the effective region; One or both of the lower electrode and the
upper electrode include a plurality of active region electrode portions independently connected
to the effective region, and a plurality of reference region electrode portions independently
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connected to the reference region. What is claimed is: 1. A correction method for an ultrasonic
probe having a sound wave transducer, comprising: a first step of detecting an output value
reflecting the electrical property of the reference area from the reference area electrode unit; and
based on the electrical property Ultrasonic wave including a second step of correcting one or
both of an output value from the effective area electrode section and an input value to the
effective area electrode section so as to cancel out the variation in piezoelectric characteristics
among the effective areas. Provide a method of probe correction.
[0010]
According to the present invention, it is possible to provide an ultrasonic probe capable of
correcting variation in the same plane of an ultrasonic transducer and variation in electrical
characteristics among a plurality of ultrasonic transducers.
[0011]
1A to 1C are diagrams showing the configuration of an ultrasonic probe according to an
embodiment of the present invention.
FIG. 2 is a cross-sectional view of an ultrasonic transducer.
3A and 3B are plan views of the piezoelectric thin film and the lower electrode.
4A and 4B are diagrams showing the configuration of an ultrasonic imaging apparatus according
to an embodiment of the present invention.
[0012]
Hereinafter, an ultrasonic probe and an ultrasonic probe correction method according to an
embodiment of the present invention will be described.
[0013]
[Configuration of Ultrasonic Probe] FIGS. 1A to 1C are diagrams showing the configuration of the
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ultrasonic probe.
FIG. 1A is a view schematically showing the configuration of the ultrasonic probe, FIG. 1B is a
view schematically showing the configuration of the transducer unit, and FIG. 1C is a view
schematically showing the configuration of the ultrasonic transducer FIG. FIG. 2 is a crosssectional view of the area indicated by the broken line in FIG. 1C. 3A and 3B are plan views of the
piezoelectric thin film and the lower electrode. FIG. 3A is a plan view of the piezoelectric thin
film, and FIG. 3B is a plan view of the lower electrode.
[0014]
As shown in FIG. 1A, the ultrasonic probe 100 corrects, for example, variations in electrical
characteristics among the transducer unit 102, a holder for accommodating the transducer unit
102, and the transducer unit 102 (see FIG. 1A). 2) and. The holder is, for example, an acoustic
matching layer disposed on the surface of the transducer unit 102, and disposed on the surface
of the acoustic matching layer and exposed to the surface of the ultrasonic probe 100 (to form a
surface) And an acoustic lens disposed.
[0015]
As shown in FIG. 1B, in the transducer unit 102, transducer arrays 104 are arranged in parallel.
As shown in FIG. 1C, the transducer array 104 has ultrasonic transducers 106 arranged in
parallel. In the present embodiment, 45696 ultrasonic transducers 106 are arranged in parallel.
[0016]
As shown in FIG. 2, the ultrasonic transducer 106 has a diaphragm portion 111, a support
portion 112 for supporting the diaphragm portion 111 therearound, and a piezoelectric element
portion 113 disposed on the diaphragm portion 111. . The diaphragm portion 111 and the
support portion 112 are made of silicon, for example. In the present embodiment, the diaphragm
portion 111 and the support portion 112 are integrally formed.
[0017]
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The piezoelectric element portion 113 has a piezoelectric film 121, and a lower electrode 122
and an upper electrode 123 which are disposed to sandwich the piezoelectric film 121 from the
front and back. In the piezoelectric element portion 113, the lower electrode 122 is stacked on
the surface of the diaphragm portion 111, the piezoelectric film 121 is stacked on the surface of
the lower electrode 122, and the upper electrode 123 is stacked on the surface of the
piezoelectric film 121.
[0018]
The piezoelectric film 121 is, for example, a thin film of a piezoelectric material having a
perovskite structure containing lead, more specifically, so-called lead zirconate titanate (PZT).
The thickness of the piezoelectric film 121 is preferably 1/4 or less of the acoustic wavelength,
more preferably 1/10 or less, and for example, in the range of 0.1 to 10 μm. . In the MEMS
using a thin film as in this embodiment, “flexural vibration” that is bent by locally thinning the
piezoelectric film is used. As a result, a region where the piezoelectric film is to be bent and a
region not to be bent exist, and a region not to be bent can be used for the correction method of
the ultrasonic probe 100.
[0019]
As shown in FIGS. 2 and 3A, the piezoelectric film 121 has an effective area 131 and a reference
area 132. Here, the “effective region 131” means a region that vibrates largely at the time of
piezoelectric conversion. The “reference area 132” means an area that vibrates smaller at the
time of piezoelectric conversion than the effective area 131. The effective area 131 and the
reference area 132 are areas which are relatively determined as a result of comparing the
magnitude of vibration at the time of piezoelectric conversion, and can not be uniquely
determined. Thus, the effective area 131 and the reference area 132 are different for each
ultrasonic transducer 106. The reference area 132 includes a first reference area 133
corresponding to the support portion 112 and a second reference area 134 other than the first
reference area 133.
[0020]
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In the present embodiment, the central portion of the piezoelectric film 121 and the outer
peripheral portion of the piezoelectric film 121 are the reference region 132. That is, the central
portion of the piezoelectric film 121 is the second reference region 134, and the outer peripheral
portion of the piezoelectric film 121 is the first reference region 133. Further, an annular region
between the central portion of the piezoelectric film 121 and the outer peripheral portion of the
piezoelectric film 121 is an effective region 131.
[0021]
As shown in FIGS. 2 and 3B, the lower electrode 122 is stacked on the surface of the diaphragm
portion 111, and the piezoelectric film 121 is stacked on the surface opposite to the diaphragm
portion 111. The lower electrode 122 is, for example, a thin layer of gold. The thickness of the
lower electrode 122 is 50 to 500 nm, preferably 100 to 200 nm.
[0022]
The lower electrode 122 has an effective area electrode section 141 and a reference area
electrode section 142. The effective area electrode section 141 and the reference area electrode
section 142 are separated so that the effective area electrode section 141 and the reference area
electrode section 142 are electrically independent. For example, the effective area electrode
section 141 and the reference area electrode section 142 are separated by a space so that the
effective area electrode section 141 and the reference area electrode section 142 are not
electrically connected.
[0023]
The effective area electrode portion 141 is disposed corresponding to the effective area 131 of
the piezoelectric film 121, and is independently connected to the effective area 131 from the
back surface side. In the present embodiment, the effective area electrode portion 141 is formed
in a substantially annular shape corresponding to the effective area 131. The effective area
electrode portion 141 may be disposed in the entire effective area 131, and may be divided into
a plurality.
[0024]
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The reference region electrode portion 142 is disposed corresponding to the reference region
132 of the piezoelectric film 121, and is independently connected to the reference region 132
from the back surface side. In the present embodiment, the reference area electrode section 142
includes the first reference area electrode section 143 connected to the first reference area 133
and the second reference area electrode section 144 connected to the second reference area
134. Including.
[0025]
The upper electrode 123 is stacked on the surface of the piezoelectric film 121 opposite to the
surface on which the lower electrode 122 is disposed. The upper electrode is, for example, a thin
layer of gold. The thickness of the upper electrode 123 is 50 to 500 nm, preferably 100 to 200
nm.
[0026]
The correction unit 108 is a device for correcting one or both of the output value from the
effective area electrode unit 141 and the input value to the effective area electrode unit 141
based on the output value from the reference area electrode unit 142. These output values and
input values are, for example, voltage values. The correction unit 108 includes, for example, a
storage unit and a calculation unit, and is a CPU or the like that performs various calculation
processes as described below.
[0027]
If the electrical characteristic of the reference region 132 is “the charge remaining in the
reference region 132 after polarization”, the correction unit 108 first detects the output value
from the reference region electrode unit 142. Then, the correction unit 108 obtains the amount
of charge remaining in the reference region 132 after polarization, obtains the amount of
polarization in the effective region, and cancels out the variation in the amount of polarization
between the effective regions 131 from the effective region electrode portion 141. One or both
of the voltage value and the input value to the effective area electrode unit 141 are corrected.
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[0028]
When the electrical characteristic of the reference region 132 is “charge by electrostatic
induction in the reference region 132,” the correction unit 108 first outputs the output value
from the reference region electrode unit 142 including the charge by electrostatic induction in
the reference region 132. To detect. Then, the correction unit 108 obtains the charge amount
due to electrostatic induction in the reference region 132, obtains the charge amount due to
electrostatic induction between the effective regions 131, and is effective so as to cancel the
electrostatic induction between the effective regions 131. One or both of the voltage value from
the area electrode unit 141 and the input value to the effective area electrode unit 141 are
corrected.
[0029]
When the electrical characteristic of the reference region 132 is “charge due to temperature of
the reference region 132 due to temperature distribution between the reference regions 132”,
the correction unit 108 includes charge due to the temperature of the reference region 132 due
to temperature distribution between the reference regions 132. The output value from the
reference area electrode unit 142 is detected. Then, the correction unit 108 obtains the charge
amount due to the temperature of the reference region 132, obtains the variation of the charge
amount due to the temperature distribution between the effective regions 131, and cancels the
temperature variation between the effective regions 131. One or both of the output value from
131 and the input value to the effective area electrode unit 141 are corrected.
[0030]
When the electrical characteristic of the reference area 132 is “charge by reception of acoustic
signal in the reference area 132”, the correction unit 108 outputs the output value from the
reference area electrode unit 142 including charge by reception of the acoustic signal in the
reference area 132. To detect. Then, the correction unit 108 obtains the charge amount upon
reception of the acoustic signal in the reference region 132, obtains the variation of the charge
amount due to the acoustic signal between the effective regions 131, and cancels out the
variation of the acoustic signals between the effective regions 131. Then, one or both of the
output value from the effective area 131 and the input value to the effective area electrode unit
141 are corrected.
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[0031]
The support portion 112 is integrally formed with the diaphragm portion 111. The shape of the
support portion 112 is not particularly limited as long as the support portion 112 can support
the ultrasonic transducer 106. In the present embodiment, the support portion 112 has a noncylindrical shape such as a cylindrical shape or an elliptical shape. The ultrasonic transducer 106
is supported on the upper surface of the cylinder.
[0032]
The acoustic matching layer is a layer for matching the acoustic characteristics of the
piezoelectric element unit 113 and the acoustic lens. The acoustic matching layer is formed in a
single layer structure or a laminated structure, for example, by a resin such as epoxy resin or
silicone resin, or an inorganic material such as aluminum or an alloy thereof. Further, the
acoustic lens is made of a soft material having an acoustic impedance intermediate between the
subject and the acoustic matching layer. The material is, for example, silicone rubber, examples
of which include silicone rubber and fluorosilicone rubber. Adhesives commonly used in the art
(e.g., epoxy-based adhesives, silicone-based adhesives, etc.) are used for the placement of the
acoustic matching layer and the acoustic lens, as required.
[0033]
[Method of Correcting Ultrasonic Probe] Next, a method of correcting the ultrasonic probe 100
will be described. The correction method of the ultrasonic probe 100 includes a variation in
piezoelectric characteristics among the effective regions 131 based on the first step of detecting
an output value reflecting the electrical characteristics of the reference region 132 from the
reference region electrode unit 142 and the electrical characteristics. And a second step of
correcting one or both of the output value from the effective area electrode unit 141 and the
input value to the effective area electrode unit 141 so as to cancel out. Here, “the electrical
characteristics of the reference region 132” means (1) charge remaining in the reference region
132 after polarization, (2) charge by electrostatic induction in the reference region 132, and (3)
temperature distribution between the reference regions 132. The charge due to the temperature
of the reference region 132 due to the (4) charge due to the reception of the acoustic signal in
the reference region 132, etc. are included. Below, the correction method of the ultrasonic probe
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100 in the case of each electrical property is demonstrated. The correction method of these
ultrasonic probes 100 is a method of correcting the entire ultrasonic probe 100 by correcting
each ultrasonic transducer 106 unit.
[0034]
(Method 1 of Correcting Ultrasonic Probe) A method of correcting the ultrasonic probe 100 in
the case where the electrical characteristic of the reference region 132 is “the charge remaining
in the reference region 132 after polarization” will be described.
[0035]
The first step of the correction method of the ultrasonic probe 100 in the case where the
electrical characteristic of the reference region 132 is “the charge remaining in the reference
region 132 after polarization” is the step of detecting the output value from the reference
region electrode unit 142 .
In the second step, a step of determining the amount of charge remaining in the reference region
132 after polarization, a step of determining the amount of polarization of the effective region,
and an effective region electrode portion 141 so as to cancel out the variation of the polarization
amount between the effective regions 131. Correcting one or both of the voltage value from V.
and the input value to the effective area electrode unit 141.
[0036]
In the first step, the output value from the reference area electrode unit 142 is detected. It is
known that charges remain in the reference region 132 for a certain period after polarization.
Therefore, in the first step, the output value from the reference area electrode unit 142 including
the charge remaining in the reference area 132 after polarization is detected.
[0037]
In the step of obtaining the charge amount of the reference region 132 in the second step, the
charge amount of the reference region 132 is obtained from the output value (voltage value)
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from the reference region electrode unit 142. Specifically, the charge amount of the reference
region 132 is obtained as the charge amount with respect to the voltage value from the reference
region electrode unit 142 from the relationship between the charge amount and the voltage
value obtained in advance.
[0038]
In the step of determining the polarization amount of the effective region in the second step, the
polarization amount of the effective region 131 is determined based on the charge amount of the
reference region 132. Specifically, the charge amount of the effective region 131 is estimated
based on the charge amount of the reference region 132 using the proximity of the reference
region 132 and the effective region 131. Then, from the charge amount of the effective region
131, the polarization amount that would have remained in the effective region 131 is
determined. Specifically, the amount of polarization of the effective region 131 is determined as
the amount of polarization relative to the amount of charge of the effective region 131 from the
relationship between the amount of charge of the effective region 131 and the amount of
polarization of the effective region 131 obtained beforehand.
[0039]
In the correction method of the second step, one or both of the voltage value from the effective
area electrode unit 141 and the input value to the effective area electrode unit 141 are corrected
so as to cancel the variation of the polarization amount between the effective areas 131.
Specifically, the voltage value from the effective area electrode portion 141 and the effective area
electrode portion 141 are eliminated so as to eliminate the variation between the polarization
amount of the effective area 131 to be corrected and the polarization amounts of other effective
areas 131. Correct one or both of the input values of. That is, only the output value from the
effective area electrode unit 141 may be corrected to eliminate the variation in the polarization
amount between the effective areas 131, or only the input value to the effective area electrode
unit 141 may be corrected. The variation of the polarization amount between 131 may be
eliminated, or only the output value from the effective region electrode portion 141 and the
input value to the effective region electrode portion 141 may be corrected to eliminate the
variation of the polarization amount between the effective regions 131. May be
[0040]
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Since the polarization process is uniformly performed on the entire piezoelectric film 121, the
amount of polarization remaining in the first reference region 133 and the second reference
region 134 is considered to be substantially the same. Therefore, in the first step, the output
value from the first reference area electrode unit 143 including the charge remaining in the first
reference area 133 after polarization is detected, or the charge including the charge remaining in
the second reference area 134 is It is preferable to detect the output value from the reference
region electrode unit 144. In the first step, the output value from the first reference region
electrode portion 143 including the charge remaining in the first reference region 133 after
polarization is detected, and the charge including the charge remaining in the second reference
region 134 is The output value from the reference area electrode unit 144 may be detected. In
this case, an average value of the output value from the first reference area electrode unit 143
and the output value from the second reference area electrode unit 144 is used as the output
value from the reference area electrode unit 142.
[0041]
(Method 2 of Correction of Ultrasonic Probe) The first step of the method of correction of the
ultrasonic probe 100 in the case where the electrical property of the reference region 132 is
“charge by electrostatic induction in the reference region 132” is the electrostatics in the
reference region 132. This is a step of detecting an output value from the reference area
electrode portion 142 including a charge due to induction. In the second step, a step of obtaining
the charge amount by electrostatic induction in the reference region 132, a step of obtaining the
charge amount by electrostatic induction between the effective regions 131, and an electrostatic
induction between the effective regions 131 are cancelled. Correcting one or both of the voltage
value from the effective area electrode unit 141 and the input value to the effective area
electrode unit 141.
[0042]
In the first step, the output value from the reference area electrode unit 142 is detected. In the
ultrasonic probe 100, the piezoelectric film 121 may vibrate largely due to electrostatic
induction. Therefore, in the first step, the output value from the reference area electrode unit
142 including the charge generated in the reference area 132 by the generated electrostatic
induction is detected. In the first step, it is preferable to detect the output value from the first
reference area electrode unit 143.
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[0043]
In the step of determining the charge amount of the reference region in the second step, the
charge amount of the reference region 132 due to electrostatic induction is determined from the
output value (voltage value) from the reference region electrode unit 142. Specifically, the charge
amount due to electrostatic induction in reference region 132 is determined as the charge
amount relative to the voltage value from reference region electrode portion 142 from the
relationship between the charge amount due to electrostatic induction and the voltage value
obtained in advance. .
[0044]
In the step of obtaining the charge amount between the effective regions 131 in the second step,
the charge amount between the effective regions is obtained based on the charge amount of the
reference region 132.
[0045]
In the correction method of the second step, one or both of the voltage value from the effective
area electrode unit 141 and the input value to the effective area electrode unit 141 are corrected
so as to cancel the electrostatic induction between the effective areas 131.
Specifically, the voltage value from the effective area electrode section 141 and the effective area
electrode section are eliminated so as to eliminate the variation between the electrostatic
induction of the effective area 131 to be corrected and the electrostatic induction of the other
effective areas 131. Correct one or both of the input values to 141. That is, only the output value
from the effective area electrode unit 141 may be corrected to eliminate the variation in
electrostatic induction between the effective areas 131, or only the input value to the effective
area electrode unit 141 may be corrected. Variations in electrostatic induction between the
regions 131 may be eliminated, and both of the voltage value from the effective region electrode
portion 141 and the input value to the effective region electrode portion 141 may be corrected
to generate electrostatic induction between the effective regions 131. Variation of the
[0046]
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(Method 3 of Correction of Ultrasonic Probe) The first step of the method of correction of the
ultrasonic probe 100 in the case where the electrical property of the reference region 132 is
“the charge due to the temperature of the reference region 132 due to the temperature
distribution between the reference regions 132” is This is a step of detecting the output value
from the reference area electrode portion 142 including the charge due to the temperature of the
reference area 132 due to the temperature distribution between the reference areas 132. In the
second step, the step of obtaining the charge amount due to the temperature of the reference
region 132, the step of obtaining the variation of the charge amount due to the temperature
distribution between the effective regions 131, and the temperature variation among the
effective regions 131 are canceled out. Correcting one or both of the output value from the
effective area 131 and the input value to the effective area electrode unit 141.
[0047]
In the first step, the output value from the reference area electrode unit 142 is detected. In the
ultrasonic probe 100, the detection value detected from the reference area electrode unit 142
may differ depending on the temperature. Therefore, in the first step, the output value from the
reference area electrode unit 142 including the charge due to the temperature of the reference
area 132 due to the temperature distribution between the reference areas 132 is detected. In
addition, since the first reference region 133 is in contact with the support portion 112, the
temperature of the first reference region 133 may be influenced by the support portion 112.
Therefore, in the first step, it is preferable to detect the output value from the second reference
area electrode unit 144.
[0048]
In the step of obtaining the charge amount according to the temperature of the reference region
132 in the second step, the charge amount according to the temperature of the reference region
132 is obtained from the output value (voltage value) from the reference region electrode portion
142. Specifically, the charge amount according to the temperature of the reference region 132 is
obtained as the charge amount with respect to the voltage value from the reference region
electrode unit 142 from the relationship between the charge amount according to the
temperature and the voltage value obtained in advance.
[0049]
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In the step of obtaining the charge amount between the effective regions 131 in the second step,
the charge amount between the effective regions 131 is obtained based on the charge amount of
the reference region 132.
[0050]
In the correction method of the second step, one or both of the output value from the effective
region 131 and the input value to the effective region electrode portion 141 are corrected so as
to cancel out the variation of the charge amount between the effective regions 131.
Specifically, the voltage value from the effective area electrode unit 141 and the effective area
are eliminated so as to eliminate the variation between the charge quantity at the temperature of
the effective area 131 to be corrected and the charge quantity at the temperature of the other
effective area 131. One or both of the input values to the electrode unit 141 are corrected. That
is, only the output value from the effective area electrode unit 141 may be corrected to eliminate
the variation in charge amount at the temperature between the effective areas 131, or only the
input value to the effective area electrode unit 141 may be corrected. It is also possible to
eliminate the variation of the charge amount at the temperature between the effective regions
131, correct both the voltage value from the effective region electrode portion 141 and the input
value to the effective region electrode portion 141, and It is possible to eliminate the variation of
the charge amount in
[0051]
(Method 4 of Correction of Ultrasonic Probe) The first step of the method of correction of the
ultrasonic probe 100 in the case where the electrical characteristic of the reference region 132 is
“charge by reception of acoustic signal in the reference region 132” is acoustic in the
reference region 132. This is a step of detecting an output value from the reference area
electrode unit 142 including a charge due to the reception of a signal. In the second step, a step
of obtaining the charge amount upon reception of the acoustic signal in the reference region
132, a step of obtaining the variation of the charge amount due to the acoustic signal between
the effective regions 131, and a variation of the acoustic signals among the effective regions
Correcting one or both of the output value from the effective area 131 and the input value to the
effective area electrode unit 141 so as to cancel out.
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[0052]
In the first step, the output value from the reference area electrode unit 142 is detected. In the
transducer unit 102 according to the present embodiment, the reference region 132 has low
responsiveness to the acoustic signal, and the effective region has high responsiveness to the
acoustic signal. Therefore, in the first step, it is preferable to detect the output value from the
first reference area electrode unit 143 including the charge due to the reception of the acoustic
signal in the reference area 132.
[0053]
In the step of determining the charge amount of the reference region in the second step, the
charge amount due to the reception of the acoustic signal of the reference region 132 is
determined from the output value (voltage value) from the reference region electrode unit 142.
Specifically, the charge amount upon reception of the acoustic signal in the reference region 132
is the charge amount relative to the voltage value from the reference region electrode unit 142
from the relationship between the charge amount upon reception of the acoustic signal and the
voltage value obtained in advance. Ask as.
[0054]
In the step of obtaining the charge amount between the effective regions 131 in the second step,
the variation of the charge amount due to the acoustic signal between the effective regions is
obtained based on the charge amount of the reference region 132.
[0055]
In the correction method of the second step, one or both of the voltage value from the effective
area electrode unit 141 and the input value to the effective area electrode unit 141 are corrected
so as to cancel the variation of the acoustic signal between the effective areas 131.
Specifically, the voltage value from the effective area electrode unit 141 and the effective area
electrode unit 141 are eliminated so as to eliminate the variation between the acoustic signal of
the effective area 131 to be corrected and the acoustic signal of the other effective area 131.
Correct one or both of the input values of. That is, only the output value from the effective area
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electrode unit 141 may be corrected to eliminate the variation of the acoustic signal between the
effective areas 131, or only the input value to the effective area electrode unit 141 may be
corrected. Variations in the acoustic signal between 131 may be eliminated, and both of the
voltage value from the effective area electrode unit 141 and the input value to the effective area
electrode unit 141 may be corrected to make the variation in acoustic signal between the
effective areas 131 You may lose it.
[0056]
As described above, according to the correction method of the ultrasonic probe 100 according to
the present invention, the piezoelectrics of (1) to (4) described above between the effective areas
131 are based on the output value in consideration of the electrical characteristics of the
reference area 132 One or both of the output value from the effective area electrode unit 141
and the input value to the effective area electrode unit 141 are corrected so as to cancel the
variation in the characteristics. Thereby, the output value (voltage value) from the ultrasonic
probe 100 can be made constant. Further, since the correction information (voltage value) can be
obtained from the piezoelectric film 121 to be subjected to the piezoelectric conversion, even if
the ultrasonic probe 100 is deteriorated, the correction can be appropriately performed.
[0057]
[Configuration of Ultrasonic Imaging Device] Next, the configuration of an ultrasonic imaging
device 200 having the above-described ultrasonic probe 100 will be described. The configuration
of the ultrasonic imaging apparatus 200 is not particularly limited as long as the ultrasonic probe
100 described above is included, and a known configuration can be adopted. 4A and 4B are
diagrams showing the configuration of an ultrasonic imaging apparatus. FIG. 4A is a view
schematically showing the configuration of the ultrasonic imaging apparatus, and FIG. 4B is a
block diagram showing the electrical configuration of the ultrasonic imaging apparatus.
[0058]
As shown in FIGS. 4A and 4B, the ultrasonic imaging apparatus 200 is disposed on the apparatus
main body 201, the ultrasonic probe 100 connected to the apparatus main body 201 via the
cable 203, and the apparatus main body 201. And an input unit 204 and a display unit 209.
[0059]
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The device body 201 is connected to each of the control unit 205 connected to the input unit
204, the transmission unit 206 and the reception unit 207 connected to the control unit 205 and
the cable 203, and the reception unit 207 and the control unit 205. And an image processing
unit 208.
The control unit 205 and the image processing unit 208 are connected to the display unit 209,
respectively.
[0060]
The input unit 204 is, for example, a device for inputting data such as a command instructing
start of diagnosis or the like and personal information of a subject. The configuration of the input
unit 204 is not particularly limited as long as the above-described function can be exhibited. The
input unit 204 is, for example, an operation panel or a keyboard provided with a plurality of
input switches.
[0061]
The control unit 205 is a circuit that controls the entire ultrasonic imaging apparatus 200. The
control unit 205 controls the ultrasonic probe 100, the input unit 204, the transmission unit
206, the reception unit 207, the image processing unit 208, and the display unit 209 in
accordance with the respective functions. The control unit 205 includes, for example, a
microprocessor, a memory element, and peripheral circuits thereof.
[0062]
The transmission unit 206 transmits, for example, the signal from the control unit 205 to the
ultrasonic probe 100. Specifically, the transmission unit 206 is a circuit that supplies a drive
signal, which is an electrical signal, to the ultrasound probe 100 via the cable 203 according to
the control of the control unit 205, and generates the transmission ultrasound in the ultrasound
probe 100. is there. For example, the reception unit 207 receives a signal from the ultrasound
probe 100 and outputs the signal to the control unit 205 or the image processing unit 208.
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Specifically, the receiving unit 207 is a circuit that receives a reception signal, which is an
electrical signal, from the ultrasound probe 100 via the cable 203 under the control of the
control unit 205.
[0063]
The image processing unit 208 is a circuit that forms an image (ultrasound image) representing
an internal state inside the subject based on the signal received by the receiving unit 207, for
example, under the control of the control unit 205. For example, the image processing unit 208
generates a digital signal processor (DSP) that generates an ultrasound image of a subject, and a
digital-to-analog conversion circuit (DAC circuit that converts a signal processed by the DSP from
digital signals to analog signals). Etc.).
[0064]
The display unit 209 is a device for displaying an ultrasonic image of the subject generated by
the image processing unit 208 according to the control of the control unit 205, for example. The
display unit 209 is, for example, a display device such as a CRT display, a liquid crystal display
(LCD), an organic EL display, a plasma display, or a printing device such as a printer.
[0065]
In the present embodiment, the lower electrode 122 constitutes the effective region electrode
portion 141 and the reference region electrode portion 142, but the upper electrode 123
constitutes the effective region electrode portion 141 and the reference region electrode portion
142. Alternatively, the lower electrode 122 and the upper electrode 123 may constitute the
effective area electrode section 141 and the reference area electrode section 142. When the
upper electrode 123 constitutes the effective area electrode portion 141 and the reference area
electrode portion 142, the upper electrode 123 is the effective area electrode portion 141
connected independently to the effective area 131 from the surface, and the reference area from
the surface And 132 are independently connected to the reference area electrode portion 142.
Further, when the lower electrode 122 and the upper electrode 123 constitute the effective area
electrode portion 141 and the reference area electrode portion 142, the upper electrode 123 is
an effective area electrode independently connected from the surface to the effective area 131.
And a reference area electrode section 142 connected to the reference area 132 independently
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from the surface. The lower electrode 122 has an effective area electrode portion 141 connected
independently to the effective area 131 from the back surface, and a reference area electrode
portion 142 independently connected to the reference area 132 from the back surface. Further,
the upper electrode 123 may have the effective area electrode portion 141, and the lower
electrode 122 may have the reference area electrode portion 142. Further, the upper electrode
123 may have the reference region electrode portion 142, and the lower electrode 122 may have
the effective region electrode portion 141.
[0066]
In the present embodiment, the correction unit 108 is included in the ultrasound probe 100, but
may be outside the ultrasound probe 100 and, for example, in the control unit 205 of the
ultrasound diagnostic apparatus 200. Furthermore, the correction unit 108 may be configured to
be able to connect to the ultrasound diagnostic apparatus 200 from the outside.
[0067]
According to the ultrasound probe according to the present invention, it is possible to provide an
ultrasound probe having an ultrasound transducer with constant electrical characteristics.
Therefore, according to the above-mentioned correction method, it is expected that the
performance of the ultrasonic probe will be further enhanced and further spread.
[0068]
DESCRIPTION OF SYMBOLS 100 ultrasonic probe 102 transducer part 104 transducer array 106
ultrasonic transducer 108 correction part 111 diaphragm part 112 support part 113
piezoelectric element part 121 piezoelectric film 122 lower electrode 123 upper electrode 131
effective area 132 reference area 133 first reference Region 134 Second Reference Region 141
Effective Region Electrode Unit 142 Reference Region Electrode Unit 143 First Reference Region
Electrode Unit 144 Second Reference Region Electrode Unit 200 Ultrasonic Imaging Device 201
Device Body 203 Cable 204 Input Unit 205 Control Unit 206 Transmission Unit 207 Receiver
208 Image processor 209 Display
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