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DESCRIPTION JP2013243449

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DESCRIPTION JP2013243449
Abstract: To provide an ultrasonic probe with improved uniformity of an ultrasonic beam in a
lens direction and reduced side lobes with ease and high reliability. An ultrasonic probe 1
according to the present embodiment includes a plurality of piezoelectric bodies 161 arranged in
a first direction, a first electrode 165 provided on the back side of each of the plurality of
piezoelectric bodies 161, and A central portion 190 of the second electrode 181 in a second
direction orthogonal to the first direction, the second electrode 181 on the flexible printed board
18 electrically connected to the first electrode 165; Is smaller than the area of the end portion
192 of the second electrode 181. [Selected figure] Figure 3
Ultrasound probe
[0001]
Embodiments of the present invention relate to an ultrasound probe used in an ultrasound
diagnostic apparatus.
[0002]
There is an ultrasonic diagnostic apparatus that scans the inside of a subject with ultrasound and
that the internal state of the subject is imaged based on a received signal generated from a
reflected wave from inside the subject.
Such an ultrasound diagnostic apparatus transmits ultrasound into a subject via an ultrasound
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probe. The ultrasound diagnostic apparatus receives, via an ultrasound probe, a reflected wave
generated due to an acoustic impedance mismatch inside the subject. The ultrasound diagnostic
apparatus generates a reception signal based on the reception of the reflected wave.
[0003]
The ultrasonic probe generates an ultrasonic wave by the vibration of the piezoelectric body
based on the transmission signal (drive signal). The ultrasonic probe generates a reception signal
by receiving a reflected wave through the piezoelectric body. In the ultrasonic probe, a plurality
of piezoelectric bodies for generating an ultrasonic wave and generating a reception signal are
arranged in a scanning direction (also referred to as an array direction or an azimuth direction).
An ultrasonic probe in which piezoelectric bodies are arranged in one direction is called a onedimensional array probe.
[0004]
Further, an ultrasonic probe in which a plurality of piezoelectric materials are arranged in two
directions (array direction and lens direction (also referred to as elevation direction)) orthogonal
to each other is called a two-dimensional array probe. In the one-dimensional array probe, an
ultrasonic probe when the piezoelectric body is slightly divided in the elevation direction (for
example, three divisions) is called a 1.5-dimensional array probe.
[0005]
In a one-dimensional array probe, when a drive signal of a rectangular waveform is applied to
each of a plurality of piezoelectric members (hereinafter referred to as a piezoelectric element),
sidelobe generation and nonuniformity of the sound field are a problem with regard to the sound
field in the lens direction. It can be As a technique related to side lobe reduction and sound field
equalization, it is known to weight the intensity of ultrasonic waves transmitted from the
piezoelectric element (hereinafter referred to as transmission ultrasonic waves).
[0006]
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A technique relating to weighting of the intensity of transmission ultrasonic waves is, for
example, grooving a piezoelectric body along the lens direction to change the piezoelectric body
density. By this technique, the effective piezoelectric density can be gradually reduced from the
center to the end of the lens direction. Thereby, the sound pressure at the end in the lens
direction can be gradually reduced. From this, the side lobes of the ultrasonic beam can be
reduced.
[0007]
However, the above techniques have the following problems. There are deterioration of yield due
to manufacturing difficulty and increase of manufacturing cost due to increase of manufacturing
process. In addition, there is a reduction in the quality of the piezoelectric body, that is, the
reliability of the piezoelectric body, because the groove processing is performed on the
piezoelectric body. Furthermore, as the area (effective area) contributing to the vibration of the
piezoelectric body decreases, the capacitance of the piezoelectric body decreases, and the
acoustic impedance of the piezoelectric body increases. An increase in acoustic impedance leads
to a reduction in the output signal and a reduction in sensitivity. That is, the above-described
technology has many problems such as an increase in manufacturing cost, a decrease in
reliability of the piezoelectric body, and a decrease in sensitivity.
[0008]
JP 2003-9288 A JP 05-38335 A
[0009]
It is an object of the present invention to simply and reliably provide an ultrasonic probe with
improved uniformity of the ultrasonic beam in the lens direction and reduced side lobes.
[0010]
The ultrasonic probe according to the present embodiment includes a plurality of piezoelectric
members arranged in a first direction, a first electrode provided on the back surface side of each
of the plurality of piezoelectric members, and electricity facing the first electrode. And a second
electrode on the flexible printed circuit board to be connected in the second direction orthogonal
to the first direction, the area of the central portion of the second electrode being the area of the
end portion of the second electrode It is characterized by being smaller.
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[0011]
FIG. 1 is a cross-sectional view showing an example of a cross section along the lens direction in
the ultrasonic probe according to the first embodiment.
FIG. 2 is a cross-sectional view showing an example of a cross section along the array direction in
the ultrasonic probe according to the first embodiment.
3 relates to the first embodiment, and an electrode (piezoelectric back electrode) on the back side
of the piezoelectric body and an FPC (flexible printed circuit board) electrode viewed from the
ultrasonic radiation side are shown in FIG. And the FPC.
FIG. 4 relates to a first modified example of the first embodiment, and is a view showing an
example of an FPC electrode as viewed from the ultrasonic radiation side with a piezoelectric
back electrode. FIG. 5 relates to a second modification of the first embodiment and is a view
showing an example of the FPC electrode as viewed from the ultrasonic radiation side. FIG. 6 is a
diagram according to a second modified example of the first embodiment, showing an example of
the calculation result regarding the sound pressure distribution with respect to the lens direction.
FIG. 7 relates to a second modification of the first embodiment and is a view showing an example
of a beam profile in which the calculation results regarding the intensity distribution of the sound
field in the lens direction and the depth direction are indicated by isoacoustic lines is there. FIG. 8
relates to a third modification of the first embodiment and is a view showing an example of the
FPC electrode as viewed from the ultrasonic radiation side. FIG. 9 is a view according to the
second embodiment, showing the piezoelectric back electrode and the FPC electrode as viewed
from the ultrasonic radiation side, together with a cross section along the elevation direction. FIG.
10 is a diagram according to a modification of the second embodiment, showing an example of
the structure of the FPC electrode as viewed from the ultrasonic radiation side. FIG. 11 is a
diagram according to a modification of the second embodiment, showing an example of
calculation results regarding the sound pressure intensity of the transmission ultrasonic wave
with respect to the frequency of the transmission ultrasonic wave. FIG. 12 is a diagram according
to the third embodiment, showing a distribution pattern of the piezoelectric back electrode and
the FPC electrode as viewed from the ultrasonic radiation surface side. FIG. 13 relates to the third
embodiment, and is a view showing a distribution pattern of the piezoelectric back electrode and
the FPC electrode as viewed from the ultrasonic radiation surface side in the subarrayed twodimensional array probe. FIG. 14 relates to the third embodiment, and is a view showing a
distribution pattern of the piezoelectric back electrode and the FPC electrode as viewed from the
ultrasonic radiation surface side.
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[0012]
Hereinafter, the ultrasonic probe according to the present embodiment will be described with
reference to the drawings. In the following description, components having substantially the
same configuration are denoted by the same reference numerals, and redundant description will
be made only when necessary.
[0013]
First Embodiment FIG. 1 is a cross-sectional view showing an example of a cross section along a
lens direction (also referred to as an elevation direction) according to an ultrasonic probe 1 of the
first embodiment. The ultrasound probe 1 according to the first embodiment is a onedimensional array probe. The lens direction is the major axis direction of the transducer 16 when
the ultrasonic probe 1 is a one-dimensional array probe. The direction orthogonal to the lens
direction and in which the transducers 16 are arranged is called an array direction (also referred
to as an azimuth direction).
[0014]
FIG. 2 is a cross-sectional view showing an example of a cross section along the array direction in
the ultrasonic probe 1 according to the first embodiment. The ultrasonic probe 1 includes an
acoustic lens 10, a first acoustic matching layer 12, a second acoustic matching layer 14, a
vibrator 16, a flexible printed circuit (hereinafter referred to as FPC) 18, a backing material
(backing) material) 20.
[0015]
The acoustic lens 10 has a function of causing an ultrasonic wave generated by a piezoelectric
body 161 described later to converge in the lens direction. The acoustic lens 10 may have a
function of causing ultrasonic waves generated by the piezoelectric body 161 described later to
converge in the array direction.
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[0016]
The first acoustic matching layer 12 and the second acoustic matching layer 14 are provided on
the back side of the acoustic lens 10. Adjusting the acoustic impedance of the object and the
piezoelectric body 161 by adjusting physical parameters such as the velocity of sound, thickness,
and acoustic impedance in the first acoustic matching layer 12 and the second acoustic matching
layer 14 it can.
[0017]
Specifically, the first acoustic matching layer 12 and the second acoustic matching layer 14
suppress the reflection of ultrasonic waves resulting from the difference between the acoustic
impedance of the substance related to the subject and the acoustic impedance of the piezoelectric
body 161. The first acoustic matching layer 12 is provided on the back side of the acoustic lens
10. The second acoustic matching layer 14 is provided on the back side of the first acoustic
matching layer 12. The acoustic matching layer may be a single layer. Also, the acoustic
matching layer may have three or more layers.
[0018]
The vibrator 16 includes a piezoelectric body 161, a ground electrode (hereinafter referred to as
a piezoelectric front electrode) 163 provided on the ultrasonic radiation surface side (front side)
of the piezoelectric body 161, and an ultrasonic radiation surface. And a signal electrode
(hereinafter referred to as a piezoelectric back electrode) 165 provided on the side opposite to
the side (hereinafter referred to as the back side). A piezoelectric front electrode 163 is bonded
to the front side of the piezoelectric body 161. The piezoelectric front electrode 163 is connected
to a grounding signal line in an FPC base 183 described later via an electrical wiring. The
piezoelectric front electrode 163 is provided over the entire front surface of the plurality of
transducers 161.
[0019]
The piezoelectric front electrode 163 may be provided between the acoustic lens 10 and the first
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acoustic matching layer 12. At this time, the first acoustic matching layer 12 and the second
acoustic matching layer 14 have conductivity. Also, the piezoelectric front electrode 163 may be
provided between the first acoustic matching layer 12 and the second acoustic matching layer
14. At this time, the second acoustic matching layer 14 has conductivity.
[0020]
A piezoelectric back electrode 165 is bonded to the back side of the piezoelectric body 161. The
piezoelectric back electrode 165 is provided over the entire back surface of the piezoelectric
body 161. The piezoelectric back electrode 165 is electrically connected to an FPC electrode 181
provided on an FPC base 183 described later.
[0021]
The piezoelectric body 161 is made of a specific piezoelectric ceramic formed in a rectangular
shape with the lens direction as the long axis and the array direction as the short axis. The
piezoelectric body 161 generates an ultrasonic wave in response to a drive signal (drive pulse
signal) supplied from an ultrasonic diagnostic device (not shown) via a plurality of electronic
circuit boards. The piezoelectric body 161 receives an ultrasonic wave reflected by a substance
related to a subject and generates an echo signal (electric signal). The generated echo signals are
supplied to the ultrasonic diagnostic apparatus via a plurality of electronic circuit boards (not
shown).
[0022]
The FPC 18 includes an FPC electrode 181 electrically connected to the piezoelectric back
electrode 165 on the front side, a base layer of an insulator (hereinafter referred to as an FPC
base) 183 serving as a base of the FPC 18, and piezoelectric by reception of ultrasonic waves. It
has a signal line (hereinafter referred to as an FPC signal line) 185 for taking out an electric
signal generated by the body 161 from the ultrasonic probe 1 and a grounding signal line for
grounding the piezoelectric front electrode 163. The FPC electrode 181 will be described in
detail later. The FPC signal line 185 may be electrically connected to the back side of the FPC
base 183 via a through hole. At this time, the ground signal line is provided on the front side of
the FPC base 183.
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[0023]
The backing material (backing material) 20 is provided on the back surface of the FPC 18. The
backing material 20 supports the FPC 18, the vibrator 16, the second acoustic matching layer
14, the first acoustic matching layer 12, and the acoustic lens 10. The backing material 20
damps the transducer 16 to shorten the emitted ultrasonic pulse. The thickness of the backing
material 20 is set to a thickness sufficient for the wavelength of the used ultrasonic wave, that is,
a thickness at which ultrasonic waves in the back direction are sufficiently attenuated, in order to
maintain acoustic characteristics well.
[0024]
FIG. 3 is a view showing the piezoelectric back electrode 165 and the FPC electrode 181 as
viewed from the front side together with the vibrator 16 and the FPC 18 in the cross-sectional
view of FIG. As shown in FIG. 3, the piezoelectric back electrode 165 has the same width in the
array direction as the width of the piezoelectric body 161 in the array direction. The piezoelectric
back electrode 165 has the same width in the lens direction as the width of the piezoelectric
body 161 in the lens direction. That is, the piezoelectric back electrode 165 has the same area as
the back surface of the piezoelectric body 161.
[0025]
The FPC electrode 181 has a structure in which the width in the array direction continuously
increases from the central portion 190 to the end portion 192 in the lens direction. This
structure is applied to each of the plurality of FPC electrodes respectively corresponding to the
plurality of transducers in the one-dimensional array probe 1. As shown in FIG. 3, the area of the
central portion 190 of the FPC electrode 181 is smaller than the area of the end portion 192 of
the FPC electrode 181. In addition, the width (for example, c) in the array direction of the central
portion 190 of the FPC electrode 181 is shorter than the width (for example, d) in the array
direction of the end portion 192 of the FPC electrode 181 (c <d). The shape of the FPC electrode
181 depending on the lens direction is formed by, for example, a photomask, an etching process,
or the like.
[0026]
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The increase in width in the array direction from the central portion 190 to the end portion 192
of the FPC electrode 181 is a structure that increases according to the shape of a specific
function instead of linearly increasing as shown in FIG. It is also good.
[0027]
An adhesive 195 for bonding the FPC base 183 and the piezoelectric back electrode 165 is
provided in a region between the FPC base 183 and the piezoelectric back electrode 165 where
the FPC electrode 181 does not exist.
[0028]
First Modified Example The difference from the first embodiment is that the FPC electrode 181 is
divided in the lens direction.
FIG. 4 is a view showing an example of the structure of the FPC electrode 181 viewed from the
front side together with the piezoelectric back electrode 165 according to the first modification.
A and b in FIG. 4 correspond to a and b in FIG. 3, respectively. In the first modification, the FPC
signal line is not shown in FIG. 4 because it is provided on the back side of the FPC base 183. The
FPC electrode 181 is electrically connected to the FPC signal line on the back side of the FPC
base 183 through a through hole (not shown).
[0029]
In the FPC electrode 181 in FIG. 4, the width (for example, c) of the central portion 190 in the
lens direction is smaller than the width (for example, d) of the end portion 192 in the lens
direction (c <d). That is, the lens direction width of each of the plurality of divided FPC electrodes
is extended from the central portion 190 to the end portion 192. The above-described structure
regarding the FPC electrode 181 is applied to each of the plurality of FPC electrodes respectively
corresponding to the plurality of vibrators in the one-dimensional array probe 1.
[0030]
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Second Modification The difference from the first embodiment is that the FPC electrode 181 has
a structure in which the width in the array direction is intermittently increased from the center
portion 190 to the end portion 192 in the lens direction. Specifically, the width of the FPC
electrode 181 in the array direction increases stepwise from the central portion 190 to the end
portion 192 of the FPC electrode 181. This structure is applied to each of the plurality of FPC
electrodes respectively corresponding to the plurality of transducers in the one-dimensional
array probe 1.
[0031]
FIG. 5 is a view showing an example of the structure of the FPC electrode 181 as viewed from the
ultrasonic radiation side according to the second modified example. A and b in FIG. 5 correspond
to a and b in FIG. 3, respectively. As shown in FIG. 5, the area of the central portion 190 of the
FPC electrode 181 is smaller than the area of the end portion 192 of the FPC electrode 181. In
addition, the width (for example, c) in the array direction of the central portion 190 of the FPC
electrode 181 is shorter than the width (for example, d) in the array direction of the end portion
192 of the FPC electrode 181 (c <d).
[0032]
An adhesive 195 for bonding the FPC base 183 and the piezoelectric back electrode 165 is
provided in a region between the FPC base 183 and the piezoelectric back electrode 165 where
the FPC electrode 181 does not exist.
[0033]
FIG. 6 relates to the second modification, and in the case where the FPC electrode 181 in FIG. Is a
diagram illustrating an example of
The vertical axis in FIG. 6 indicates the sound pressure intensity (decibel dB). The horizontal axis
in FIG. 6 indicates the distance (in mm) from the lens direction, with the center in the lens
direction of the one-dimensional array probe 1 as the origin (0 mm). The broken line in FIG. 6 is
a calculation result when the FPC electrode 181 has the same shape (area) as the piezoelectric
back electrode 165 (hereinafter referred to as a reference example) as a reference. The solid line
in FIG. 6 is a calculation result in the case of having the structure of the FPC electrode 181 in
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FIG. 5 according to the second modification. The element aperture in FIG. 6 corresponds to the
width (2.5 mm) of the piezoelectric body 161 in the lens direction.
[0034]
In the calculation of the sound pressure distribution, the center frequency in the one-dimensional
array probe 1 is 12 MHz. In the calculation of the sound pressure distribution in the lens
direction, the width in the array direction of each of the plurality of transducers is 0.7 μm, and
the length in the lens direction is 2.5 mm. Further, the width (width of d) in the array direction at
the end portion 192 of the FPC electrode 181 is 250 μm. The width (c width) in the array
direction of the central portion 190 of the FPC electrode 181 is 15 μm.
[0035]
As shown in FIG. 6, in the central portion 190 in the lens direction of the FPC electrode 181, the
sound pressure intensity in the second modification is about 2 dB larger than the sound pressure
intensity in the reference example.
[0036]
FIG. 7 relates to a reference example and a second modification, and shows an example of an
ultrasonic beam profile in which the calculation results regarding the intensity distribution of the
sound field in the lens direction and the depth direction are indicated by isoacoustic lines. It is.
The vertical axis in FIG. 7 indicates the distance (in mm) from the lens direction, with the center
in the lens direction of the one-dimensional array probe 1 as the origin (0 mm). The horizontal
axis in FIG. 7 is a direction perpendicular to the ultrasonic radiation surface, and indicates the
radiation distance (depth: mm) of ultrasonic waves. A solid line of density in FIG. 7 indicates
isoacoustic lines (so-called contour lines). The interval between two adjacent solid lines
corresponds to a difference of 1 dB in sound pressure intensity.
[0037]
In the reference example in FIG. 7, since the FPC electrode 181 has a uniform and uniform
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structure with respect to the piezoelectric back electrode 165, the sound pressure is not
weighted in the lens direction. In the reference example, due to the focusing of the ultrasound by
the acoustic lens 10, the ultrasound beam is most focused at a point shallower than 15 mm in
depth. In the reference example, the ultrasonic wave diffuses at a point deeper than the
convergence point. The diffusion of the ultrasonic waves contributes to the reduction of the
resolution in the lens direction. The reduction in resolution leads to the deterioration of the
image quality of the ultrasound image generated by the ultrasound diagnostic apparatus.
[0038]
The second modification in FIG. 7 shows that the sound pressure intensity at the central portion
of the beam (near 0 mm in the lens direction) at the short distance portion (depth: 0 to 20 mm) is
higher than that in the reference example. It is done. Furthermore, it is shown that the beam
width of the ultrasonic beam is wider as compared to the reference example in the near distance
portion, that is, the uniformity of the sound field is improved. In addition, it is shown that the side
lobe in the second modified example is reduced as compared with the reference example, for
example, in the vicinity of 40 mm in depth (circled in FIG. 7).
[0039]
Third Modified Example The difference from the first embodiment is that the FPC electrode 181
has a mesh (mesh) structure. Specifically, in the central portion 190 of the FPC electrode 181 in
the lens direction, the number of void portions of the mesh in the mesh structure is larger than
that of the end portion 192 in the lens direction. That is, in the lens direction, the area of the void
portion in the central portion 190 of the FPC electrode 181 is larger than the area of the void
portion of the end portion 192 of the FPC electrode 181. When the FPC electrode 181 is bonded
to the piezoelectric back electrode 165, the void portion of the mesh structure is filled with the
nonconductive adhesive 195.
[0040]
FIG. 8 is a diagram according to the third modified example, showing an example of the structure
of the FPC electrode 181 as viewed from the ultrasonic radiation side. A and b in FIG. 8
correspond to a and b in FIG. 3, respectively. As shown in FIG. 8, the number of eyes in the mesh
structure in the central portion 190 is greater than the number of eyes in the end portion. That
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is, the density of the number of eyes in the central portion 190 of the FPC electrode 181 is
greater than the density of the number of eyes in the end portion 192. The mesh size d of the
mesh structure in the central portion 190 may be wider than the mesh size d of the mesh
structure in the end portion 192. Specifically, as shown in FIG. 8, in the structure of the FPC
electrode 181 according to the third modification, the number of eyes in the mesh structure
increases from the end portion 192 to the central portion 190 along the lens direction. Have a
mesh structure.
[0041]
According to the configuration described above, the following effects can be obtained. According
to the ultrasonic probe 1 of the present embodiment, the FPC electrode 181 has the area of the
central portion 190 of the FPC electrode 181 electrically connected to the piezoelectric back
electrode 165 in the lens direction, the end portion of the FPC electrode 181 It has a structure
that can be made smaller than 192.
[0042]
Specifically, the FPC electrode 181 of the present embodiment has a structure in which the width
in the array direction of the FPC electrode 181 continuously increases from the central portion
190 to the end portion 192 to the width in the array direction of the piezoelectric back electrode
165 . The FPC electrode 181 of the first modified example of the present embodiment divides the
FPC electrode 181 in the lens direction, whereby the area of the central portion 190 of the FPC
electrode 181 is smaller than the area of the end portion 192 in the lens direction. It has the
following structure. The FPC electrode 181 of the second modified example of this embodiment
has a structure in which the width in the array direction is intermittently increased from the
central portion 190 to the end portion 192 of the FPC electrode 181 in the lens direction. The
FPC electrode 181 of the third modified example of the present embodiment has a mesh
structure in which the number of eyes that are void portions in the mesh structure increases
from the end portion 192 to the central portion 190 along the lens direction.
[0043]
According to the structure of the FPC electrode 181 as described above, the sound pressure
intensity of the transmission ultrasonic wave can be weighted without reducing the area of the
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piezoelectric back electrode 165 in the vibrator 16. Not reducing the area of the piezoelectric
back electrode 165 corresponds to not reducing the capacitance of the vibrator 16. Not reducing
the capacitance of the transducer 16 corresponds to the ability to keep the acoustic impedance
of the transducer 16 low, and can prevent the sensitivity of the ultrasonic probe 1 from being
lowered. Therefore, according to the present ultrasonic probe 1, it is possible to give weight to
the sound pressure intensity of the transmission ultrasonic wave without reducing the sensitivity
of the ultrasonic probe 1.
[0044]
Furthermore, according to the present ultrasonic probe 1, the sound pressure intensity of the
transmitted ultrasonic wave can be made uniform in the near field (sound field of shallow depth).
In addition, according to the present ultrasonic probe 1, side lobes can be reduced in the sound
field of the transmission ultrasonic wave. Thereby, according to the ultrasonic probe 1, the
resolution in the lens direction is improved. Further, the ultrasonic probe 1 can be realized by
changing the manufacturing process of the FPC in order to make the width in the array direction
of the central portion 190 of the FPC electrode 181 narrower than the width in the array
direction of the end portion 192.
[0045]
From the above, according to the present ultrasonic probe 1, the sound field weighted with the
sound pressure intensity of the transmission ultrasonic wave without increasing the
manufacturing cost and the number of manufacturing steps and without reducing the reliability
of the members. Can be generated. In addition, according to the ultrasonic probe 1, the side lobes
are reduced, and the uniformity of the sound pressure intensity of the near field is improved.
[0046]
In addition, it is possible to combine this embodiment with the improvement technique of the
sound field in other lens directions. For example, by combining the structure of the present
embodiment with a transducer formed to weight the sound pressure intensity of transmission
ultrasonic waves in the lens direction, the sound pressure of transmission ultrasonic waves in the
lens direction can be weighted more efficiently Can be implemented.
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[0047]
Second Embodiment The second embodiment differs from the first embodiment in that a
plurality of transducers are divided in the elevation direction (lens direction) by a number smaller
than the number of the plurality of transducers arranged in the array direction. It relates to a five
dimensional array probe. In order to simplify the description below, the division of the
transducer in the elevation direction is assumed to be three.
[0048]
In the 1.5-dimensional array probe, since a large number of transducers are arranged also in the
elevation direction, the aperture can be set according to the application to enable ultrasonic
transmission. For example, when scanning a short distance (shallow depth) using a 1.5dimensional array probe, the ultrasonic diagnostic apparatus narrows the transmission ultrasonic
beam by reducing the ultrasonic transmission aperture in the 1.5-dimensional array probe. By
squeezing, high resolution ultrasound images can be generated. In addition, for example, when
scanning a long distance (deep depth) using a 1.5-dimensional array probe, the ultrasonic
diagnostic apparatus is an effective transducer by enlarging an ultrasonic wave transmission
aperture in the 1.5-dimensional array probe. The area can be expanded and echo signals can be
received with high sensitivity.
[0049]
FIG. 9 is a view according to the second embodiment, showing the piezoelectric back electrode
165 and the FPC electrode 181 viewed from the ultrasonic radiation surface side, together with a
cross section along the elevation direction. As shown in FIG. 9, the piezoelectric back electrode
165 has the same width as the width of the piezoelectric body 16 in the array direction. The
piezoelectric back electrode 165 has the same width as the width of the piezoelectric body 16 in
the elevation direction. That is, the piezoelectric back electrode 165 has the same area as the
back surface of the piezoelectric body 16, and is provided for each of the plurality of
piezoelectric bodies.
[0050]
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The FPC electrode 181 is electrically connected to the piezoelectric back electrode 165 provided
on the back side of each of the plurality of piezoelectric bodies arranged in the elevation
direction. The area of the FPC electrode 181 of the central portion 190 of the FPC electrode 181
is smaller than the area of the FPC electrode 181 of the end portion 192. As shown in FIG. 9, an
adhesive 195 for bonding the FPC base 183 and the piezoelectric back electrode 165 in a region
where the FPC electrode 181 does not exist among the FPC base 183 and the piezoelectric back
electrode 165. Is provided.
[0051]
As shown in FIG. 9, an end portion 192 sandwiched between a and b, e and f, and a central
portion in a region sandwiched between c and d respectively make the electrical signals from the
transducers A, B and C independent of each other. Are electrically isolated for removal. Through
holes (not shown) are provided on the back of each of the FPC electrode portions D, E, F. The FPC
signal line 185 is electrically connected to the through hole. The FPC signal line 185 is provided
on the back surface of the FPC base 183. Although not shown, on the front surface of the FPC
base 183, a grounding signal line for grounding the piezoelectric front electrode 163 in each of
the plurality of piezoelectric members is provided.
[0052]
(Modification) The difference from the second embodiment is that, in the FPC electrode portion E
in FIG. 9, the width of the conductor portion in the array direction is shorter than the width of
the piezoelectric body 16 and constant in the elevation direction. It is in.
[0053]
FIG. 10 is a view according to a modification of the second embodiment, showing an example of
the structure of the FPC electrode 181 as viewed from the ultrasonic radiation side.
As shown in FIG. 10, the width in the array direction of the FPC electrode portion E is 15 μm,
and is constant in the elevation direction. The width in the array direction of both the FPC
electrode portions D and F is 70 μm, which is the same as the width in the array direction of the
piezoelectric body 16. That is, the area of the central portion 190 of the FPC electrode 181 is
smaller than the area of the end portion 192 of the FPC electrode 181. The area of the FPC
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electrode portions D and F increases along the elevation direction from the end (b or e) from the
center of the FPC electrode 181 to the end (a or f) of the end portion 192. It may be
[0054]
FIG. 11 relates to a modification of the second embodiment, and in the case where the FPC
electrode 181 in FIG. 10 is used, an example of the calculation result of the sound pressure
intensity (decibel dB) with respect to the frequency of the transmission ultrasonic wave FIG. The
horizontal axis in FIG. 11 indicates the frequency (in MHz) of the ultrasonic waves (transmission
ultrasonic waves) transmitted from the 1.5-dimensional array probe. The vertical axis in FIG. 11
indicates the sound pressure intensity for each frequency of the transmission ultrasonic wave.
[0055]
The broken line in FIG. 11 shows the calculation result of the frequency spectrum of the
transmission ultrasonic wave generated at the end portion 192 of the FPC electrode 181. The
solid line in FIG. 11 shows the calculation result of the frequency spectrum of the transmission
ultrasonic wave generated at the central portion 190 of the FPC electrode 181. Referring to FIG.
11, the aperture of the ultrasonic probe corresponds to the width (2.5 mm) of the piezoelectric
body 161 in the lens direction.
[0056]
In the calculation of the frequency spectrum of the transmission ultrasonic wave in the central
portion 190 and the end portion 192 of the FPC electrode 181, the central frequency in the 1.5
dimensional array probe is 12 MHz. In the calculation of the frequency spectrum, the width in
the array direction of each of the plurality of transducers is 0.7 μm, and the length in the
elevation direction is 2.5 mm. Further, the width in the array direction of the end portion 192 of
the FPC electrode 181 is 250 μm. The width in the array direction of the central portion 190 of
the FPC electrode 181 is 15 μm.
[0057]
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As shown in FIG. 11, the sound pressure intensity of the central portion 190 in the elevation
direction of the FPC electrode 181 is larger than the sound pressure intensity at the end portion
192 in the high frequency band. That is, the frequency component of the transmission ultrasonic
wave generated in the central portion 190 corresponds to being greater than the frequency
component of the transmission ultrasonic wave generated in the end portion 192. Therefore, FIG.
11 shows that the frequency characteristic has been changed according to the present
embodiment.
[0058]
According to FIG. 11, for example, in the ultrasonic diagnostic apparatus using the 1.5dimensional array probe in the present embodiment, in the case of transmitting an ultrasonic
wave by driving a vibrator corresponding to the central portion 190 of the FPC electrode 181,
The ability to transmit higher frequency ultrasound waves with the same drive voltage allows
generation of higher resolution ultrasound images in the near field (shallow depth).
[0059]
According to the configuration described above, the following effects can be obtained.
According to the ultrasonic probe (1.5-dimensional array probe) of the present embodiment, the
FPC electrode 181 has the area of the central portion 190 of the FPC electrode 181 electrically
connected to the piezoelectric back electrode 165 in the lens direction. And the area of the end
portion 192 of the FPC electrode 181 can be made smaller.
[0060]
Specifically, the FPC electrode 181 of the present embodiment has a structure in which the width
in the array direction of the FPC electrode 181 continuously increases from the central portion
190 to the end portion 192 to the width in the array direction of the piezoelectric back electrode
165 . Further, according to the modification of the present embodiment, the width in the array
direction of the central portion 190 of the FPC electrode 181 can be narrower than the width of
the end portion 190 of the FPC electrode 181.
[0061]
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With such a structure of the FPC electrode 181, the sound pressure intensity of the transmission
ultrasonic wave can be weighted without reducing the area of the piezoelectric back electrode
165 in the vibrator 16. Furthermore, according to the present ultrasonic probe, the sound
pressure intensity of the transmission ultrasonic wave can be made uniform in the near field
(sound field of shallow depth). In addition, according to the present ultrasonic probe, side lobes
can be reduced in the sound field of transmission ultrasonic waves. Further, according to the
present ultrasonic probe, the sound pressure intensity of the frequency spectrum regarding the
central portion 190 of the FPC electrode 181 can be changed to a frequency characteristic larger
than the sound pressure intensity of the end portion 192. Thus, according to the present
ultrasonic probe, the resolution in the lens direction is improved. The ultrasonic probe can be
realized by changing the manufacturing process of the FPC 18 to make the width in the array
direction of the central portion 190 of the FPC electrode 181 narrower than the width in the
array direction of the end portion 192.
[0062]
From the above, according to the present ultrasonic probe, the sound field weight of the
transmission ultrasonic wave is weighted without increasing the manufacturing cost and the
number of manufacturing steps, and without reducing the reliability of the members. Can be
generated. In addition, according to the present ultrasonic probe, the uniformity of the sound
pressure intensity in the near-field and the resolution in the elevation direction can be reduced
by reducing the side lobes and improving the intensity of the ultrasonic transmission frequency
of the central portion 190. Improve.
[0063]
Third Embodiment The second embodiment differs from the first and second embodiments in
that in the ultrasonic probe, a two-dimensional array probe having a plurality of transducers
arranged two-dimensionally in the azimuth direction and the elevation direction. It is about
[0064]
In the two-dimensional array probe, since a large number of transducers are arranged also in the
elevation direction, ultrasonic transmission with controlled transmission aperture can be
performed according to the application.
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In each of the plurality of transducers in the two-dimensional array probe, control (for example,
phase control such as transmission and reception delay addition) regarding transmission and
reception of ultrasonic waves is possible. For this reason, the acoustic lens 10 can be omitted. In
addition, the ultrasonic diagnostic apparatus having the two-dimensional array probe can deflect
and scan the ultrasonic beam in any direction, not limited to the azimuth direction and the
elevation direction.
[0065]
A piezoelectric back electrode 165 is bonded to the back of each of the plurality of piezoelectric
bodies in the two-dimensional array probe. Further, a common electrode for grounding is
provided on the front surface of the plurality of piezoelectric members 161 in the twodimensional array probe.
[0066]
FIG. 12 is a diagram according to the third embodiment, showing an example of the distribution
pattern of the piezoelectric back electrode 165 and the FPC electrode 181 as viewed from the
ultrasonic radiation surface side. The FPC electrodes 181 are insulated for each of the plurality of
piezoelectric back electrodes 165 in order to extract electric signals generated by the plurality of
piezoelectric bodies 161 respectively corresponding to the plurality of piezoelectric back
electrodes 165. In order to simplify the drawing, the insulation of the FPC electrode 181 for each
of the plurality of piezoelectric back electrodes 165 is not shown in FIG.
[0067]
Specifically, the area of the FPC electrode 181 is increased according to the distance from the
center of the acoustic aperture of the two-dimensional array probe for each of the plurality of
piezoelectric back electrodes 165. That is, the area of the FPC electrode 181 connected to the
piezoelectric back electrode 165 in the central portion 197 of the acoustic opening is smaller
than the area of the FPC electrode 181 connected to the piezoelectric back electrode 165 in the
end portion 199 of the acoustic opening. The distribution of the size of the area of the FPC
electrode 181 in FIG. 12 has a structure in which the size increases in three or four steps radially
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from the center of the acoustic aperture.
[0068]
In other words, the area of the adhesive 195 at the central portion 197 of the acoustic opening is
larger than the area of the adhesive 195 at the end portion 199 of the acoustic opening. In FIG.
12, the distribution of the adhesive 195 is concentric, but the distribution of the adhesive 195
may be rectangular.
[0069]
In the third embodiment, the plurality of transducers in the two-dimensional array probe may be
sub-arrayed. FIG. 13 is a view showing a distribution pattern of the piezoelectric back electrode
165 and the FPC electrode 181 as viewed from the ultrasonic radiation surface side when the
two-dimensional array probe of FIG. 12 is formed into a sub-array. In FIG. 13, in the subarraying,
one FPC signal line is connected to four transducers.
[0070]
In the two-dimensional array probe of the third embodiment, scanning may be performed using a
partial region of an acoustic aperture having a plurality of transducers. At this time, the area of
the central portion of the FPC electrode 181 in the partial region is smaller than the area of the
end portion.
[0071]
FIG. 14 is a view showing an example of a distribution pattern of the FPC electrodes in which the
area of the central portion of the FPC electrode 181 in the partial region is smaller than the area
of the end portion in the two-dimensional array probe. In FIG. 14, nine transducers are arranged
in a partial region. The area of the central portion of the FPC electrode 181 in the partial region
is smaller than the area of the end portion. Also in the entire area of the two-dimensional array
probe, the area of the FPC electrode of the partial region 200 in the central portion of the
acoustic opening is smaller than the area of the FPC electrode of the partial region 201 in the
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end portion of the acoustic opening.
[0072]
According to the configuration described above, the following effects can be obtained. According
to the ultrasonic probe (two-dimensional array probe) of the present embodiment, the FPC
electrode 181 has an area of the central portion of the FPC electrode 181 corresponding to the
acoustic opening in the azimuth direction and the elevation direction. It has a structure that can
be made smaller than the area of the part.
[0073]
Specifically, the FPC electrodes 181 can be increased (for example, radially) according to the
distance from the center of the acoustic aperture of the two-dimensional array probe for each of
the plurality of piezoelectric back electrodes. In addition, the two-dimensional array probe
according to the present embodiment may be sub-arrayed.
[0074]
With such a structure of the FPC electrode 181, the sound pressure intensity of the transmission
ultrasonic wave can be weighted without reducing the area of the piezoelectric back electrode
165 in the vibrator 16. Furthermore, according to the present ultrasonic probe, the sound
pressure intensity of the transmission ultrasonic wave can be made uniform in the near field
(sound field of shallow depth). In addition, according to the present ultrasonic probe, side lobes
can be reduced in the sound field of transmission ultrasonic waves. Further, according to the
present ultrasonic probe, it is possible to change the sound pressure intensity of the frequency
spectrum related to the central portion of the acoustic aperture to a frequency characteristic
larger than the sound pressure intensity of the end portion. Thus, according to the present
ultrasonic probe, the resolution in the azimuth direction and the elevation direction is improved.
Further, the present ultrasonic probe can be realized by changing the manufacturing process of
the FPC 18.
[0075]
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From the above, according to the present ultrasonic probe, the sound field weight of the
transmission ultrasonic wave is weighted without increasing the manufacturing cost and the
number of manufacturing steps, and without reducing the reliability of the members. Can be
generated. In addition, according to the present ultrasonic probe, the uniformity of the sound
pressure intensity of the near-field and the azimuth direction and the elevation direction can be
achieved by reducing the side lobes and improving the intensity of the ultrasonic transmission
frequency in the central portion. And the resolution of
[0076]
Fourth Embodiment The fourth embodiment differs from the first to third embodiments in that a
conductor is provided between the piezoelectric back electrode 165 and the FPC electrode 181.
The piezoelectric back electrode 165 and the FPC electrode 181 in the fourth embodiment have
the same shape as viewed from the ultrasonic radiation surface. The conductor is made of, for
example, a conductive metal material such as copper, silver, or gold. When the ultrasonic probe
according to the present embodiment is a one-dimensional array probe, for example, any one of
the shapes of the FPC electrode 181 described in FIGS. 3, 4, 5 and 8 is ultrasonic radiation. It is
used as the shape of the conductor viewed from the side.
[0077]
When the ultrasonic probe according to the present embodiment is a 1.5-dimensional array
probe, for example, one of the shapes of the FPC electrodes 181 described in FIGS. It is used as
the shape of the viewed conductor. In addition, when the ultrasonic probe according to the
present embodiment is a two-dimensional array probe, for example, any one of the shapes of the
FPC electrodes 181 described in FIG. 12, FIG. 13 and FIG. It is used as the shape of the conductor
seen from
[0078]
According to the configuration described above, the following effects can be obtained. According
to the ultrasonic probe (one-dimensional array probe, 1.5-dimensional array probe, twodimensional array probe) of the present embodiment, the first to third embodiments are
performed between the piezoelectric back electrode 165 and the FPC electrode 181. A conductor
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23
having the same shape as the FPC electrode 181 according to the embodiment can be
sandwiched. By sandwiching such a conductor between the piezoelectric back electrode 165 and
the FPC electrode 181, the sound pressure intensity of the transmission ultrasonic wave is
weighted without reducing the area of the piezoelectric back electrode 165 in the vibrator 16.
can do. Furthermore, according to the present ultrasonic probe, the sound pressure intensity of
the transmission ultrasonic wave can be made uniform in the near field (sound field of shallow
depth). In addition, according to the present ultrasonic probe, side lobes can be reduced in the
sound field of transmission ultrasonic waves. Further, according to the present ultrasonic probe,
the sound pressure intensity of the frequency spectrum regarding the acoustic aperture or the
central portion of the FPC electrode 181 can be changed to a frequency characteristic larger than
the sound pressure intensity of the end portion. As a result, according to the present ultrasonic
probe, the resolution in the lens direction or in the azimuth and elevation directions is improved.
Further, the present ultrasonic probe can be realized by changing the manufacturing process of
the FPC 18.
[0079]
From the above, according to the present ultrasonic probe, the sound field weight of the
transmission ultrasonic wave is weighted without increasing the manufacturing cost and the
number of manufacturing steps, and without reducing the reliability of the members. Can be
generated. In addition, according to the present ultrasonic probe, the uniformity of the sound
pressure intensity of the near-field and the azimuth direction and the elevation direction can be
achieved by reducing the side lobes and improving the intensity of the ultrasonic transmission
frequency in the central portion. And the resolution of
[0080]
The present invention is not limited to the above embodiment as it is, and at the implementation
stage, the constituent elements can be modified and embodied without departing from the scope
of the invention. In addition, various inventions can be formed by appropriate combinations of a
plurality of constituent elements disclosed in the above embodiment. For example, some
components may be deleted from all the components shown in the embodiment. Furthermore,
components in different embodiments may be combined as appropriate.
[0081]
DESCRIPTION OF SYMBOLS 1 ... Ultrasonic probe, 10 ... Acoustic lens, 12 ... 1st acoustic
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matching layer, 14 ... 2nd acoustic matching layer, 16 ... Vibrator, 18 ... FPC (Flexible Printed
Circuit board: flexible printed circuit board), 20 ... Backing material, 161: piezoelectric body, 163:
piezoelectric front electrode, 165: piezoelectric back electrode, 181: FPC electrode, 183: FPC
base, 185: FPC signal line, 190: central portion, 192: end portion, 195: 195 Adhesive 197,
central part of acoustic opening 199 end of acoustic opening 200, partial area at central part of
acoustic opening 201 partial area at end of acoustic opening
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