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DESCRIPTION JP2017139432

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DESCRIPTION JP2017139432
Abstract: The present invention provides a method of manufacturing a piezoelectric element
capable of forming a high columnar microstructure. A method of manufacturing a piezoelectric
element including a three-dimensional structure group having a plurality of three-dimensional
structures having a width of less than 50 μm and a height of 50 μm or more is parallel to each
other with respect to a bulk material 81 formed of a piezoelectric material. A step of processing
the plurality of extending first grooves 51, a step of filling and curing the reinforcing material 64
in the first grooves 51, and a plurality of first grooves 51 with respect to the bulk material 81
filled with the reinforcing material 64. Processing a plurality of second grooves 52 extending
alternately and parallel to the surface. Thereby, a three-dimensional structure group formed at an
interval narrower than the first groove 51 is obtained. [Selected figure] Figure 5
Method of manufacturing piezoelectric element
[0001]
The present invention relates to a method of manufacturing a piezoelectric element that can be
used for ultrasonic measurement and other various ultrasonic application devices.
[0002]
A liquid jet head for ink, for example, exists as an ultrasonic application apparatus, and a
patterning method of a piezoelectric film is known as a method of manufacturing a piezoelectric
element portion incorporated in the liquid jet head (see Patent Document 1). .
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In this patterning method, a resist pattern is provided on a piezoelectric film uniformly formed on
a substrate, and the piezoelectric film is patterned by wet etching with an etching solution having
hydrochloric acid or hydrofluoric acid. Further, as a method of manufacturing a composite
piezoelectric material used for an ultrasonic sensor, a method of forming columnar
microstructures in a matrix-like two-dimensional array on a substrate of PZT has been known
(see Patent Document 2). In this method, a protective film is formed in advance on the substrate
surface of a hard and brittle material, and grooves are machined at equal intervals on the
substrate from the protective film side with a dicing saw, and then these one direction eye The
groove is filled with a reinforcing material, and grooving is performed at equal intervals in a
second direction orthogonal to one direction with a dicing saw.
[0003]
However, the methods described in Patent Documents 1 and 2 can not form deep and high
columns or other fine structures. For example, in the cutting method using a dicing saw, due to
the hard and brittle nature of the piezoelectric material, it is not possible to cut to a minute size
of 25 μm or less in side width while avoiding breakage. That is, according to the method of
Patent Document 2, although a pillar structure having a side width of about 10 μm is formed, it
is impossible to form all pillar structures having a side width of 10 μm and a height of 50 μm
without chipping by this method. It seems that even if a columnar structure satisfying such size
conditions is obtained, the strength is insufficient. For example, it is said that the ideal shape
required for the columnar microstructure constituting the composite piezoelectric material used
in the ultrasonic inspection apparatus is about 10 to 200 μm in both diameter and arrangement
interval. On the other hand, when the aspect ratio of the columnar microstructure is about 5 to 6,
it is said that the transmission and reception efficiency is the best. That is, as a height of the
columnar fine structure which comprises the said composite piezoelectric material, a thing about
50-1200 micrometers is calculated | required.
[0004]
JP, 2014-184643, A JP, 8-281641, A
[0005]
The present invention has been made in view of the above background art, and an object thereof
is to provide a method of manufacturing a piezoelectric element capable of forming a high
columnar or wall-like microstructure.
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[0006]
In order to achieve the above object, a method of manufacturing a piezoelectric element
according to the present invention is a piezoelectric comprising a three-dimensional structure
group having a plurality of three-dimensional structures formed in a column or column having a
width of less than 50 μm and a height of 50 μm or more. A method of manufacturing an
element, comprising the steps of: processing a plurality of first grooves extending in parallel to a
bulk material formed of a piezoelectric material; filling and curing a reinforcing material in the
first grooves; Processing a plurality of second grooves that extend alternately parallel to the
plurality of first grooves with respect to the bulk material filled with the reinforcing material.
Here, with regard to the groove, processing means mechanical processing and excludes chemical
etching.
[0007]
In the above manufacturing method, since the plurality of second grooves extending in parallel
with the first groove are processed in the bulk material filled with the reinforcing material, the
three-dimensional structure group formed at an interval narrower than the first groove You can
get it.
At this time, the fine shape formed between the first groove before forming the second groove is
one size larger than the fine shape after processing of the second groove, and a fine shape
without chipping or deterioration is formed. It will be relatively easy to do. Furthermore, since
the plurality of second grooves are processed in the bulk material filled with the reinforcing
material, it is possible to relatively easily obtain a three-dimensional structure of a target width
while avoiding damage due to processing.
[0008]
In a specific aspect of the present invention, in the above manufacturing method, the step of
filling and curing the reinforcing material in the second groove, and a plurality of bulk materials
extending parallel to each other crossing the first and second grooves. And d) processing the
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third groove of In this case, a three-dimensional structure group having a three-dimensional
structure arranged in a two-dimensional matrix can be obtained by the first and second grooves
and the third groove.
[0009]
In another aspect of the present invention, before processing the plurality of second grooves, the
plurality of third members extending alternately in parallel with the plurality of first grooves with
respect to the bulk material filled with the reinforcing material. The method further comprises
the step of processing the groove.
[0010]
In still another aspect of the present invention, when processing the first and second grooves, the
bulk material is not cut out, but is processed halfway along the grooves.
In this case, it is possible to effectively prevent the micro shape formed in the final stage of the
processing of each groove from becoming an independent shape and being damaged by the
stress from the processing tool acting thereon. In addition, when complete | finishing a process
so that a single 2nd groove | channel may be cut out, the quantity by which a processing tool is
covered with a bulk material decreases, and there exists a condition that a processing tool shakes
and it is easy to produce a failure.
[0011]
In still another aspect of the present invention, when processing the second groove, the
processing is advanced from the opposite direction to the first groove. In this case, the target
portion is thickened at the start of processing of the second groove, and it is possible to
effectively prevent the fine shape from being damaged by the stress from the processing tool
acting thereon. In addition, when starting processing of the second groove, even if a reinforcing
material is present, the amount by which the processing tool is covered by the bulk material is
small, and there is a circumstance that the processing tool is easily shaken and damaged. .
[0012]
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In still another aspect of the present invention, the second groove is formed in the middle of the
pair of adjacent first grooves. In this case, the first groove and the second groove form a groove
group aligned in parallel at equal intervals.
[0013]
In yet another aspect of the invention, the third grooves are arranged with a spatial period
greater than about half of the first grooves. In this case, since the width of the three-dimensional
structure between the third grooves can be made wider than the width of the three-dimensional
structure between the groove group combining the first groove and the second groove, the blade
Even if the processing stress is increased due to deterioration, breakage of the three-dimensional
structure can be reduced.
[0014]
In still another aspect of the present invention, after completing the processing of all the grooves,
removing the reinforcing material remaining in the grooves. In this case, a desired filler can be
arranged around the three-dimensional structure group.
[0015]
(A) and (B) are the top view and AA arrow sectional drawing explaining the piezoelectric element
obtained by the manufacturing method of 1st Embodiment. (A) And (B) is a top view and BB
arrow sectional drawing explaining the piezoelectric element which processed the piezoelectric
element shown in FIG. 1 further. It is a conceptual flowchart explaining the manufacturing
process of the piezoelectric element of FIG. (A)-(C) are perspective views explaining the process
of a 1st groove | channel, and filling of a reinforcement material. (A) And (B) is a perspective view
explaining a process of 2nd groove | channel, and filling of a reinforcement material. It is a
perspective view explaining processing of the 3rd slot. (A) and (B) is a figure explaining the
modification of groove processing. (A) and (B) explain the state in plan view and cross-sectional
view of the groove structure obtained by the processing method of the embodiment, (C) and (D)
the groove structure obtained by the processing method of the comparative example The states
in plan view and cross-sectional view of FIG. It is a conceptual diagram explaining the probe of
the ultrasonic inspection apparatus incorporating the piezoelectric element shown in FIG. It is a
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conceptual flowchart explaining the manufacturing process of the piezoelectric element which
concerns on 2nd Embodiment. It is a perspective view explaining processing of the 2nd slot. It is
a perspective view explaining processing of the 3rd slot. It is a perspective view explaining the
piezoelectric element of a modification.
[0016]
First Embodiment A method of manufacturing a piezoelectric element according to a first
embodiment of the present invention will be described below with reference to the drawings.
[0017]
With reference to FIGS. 1 (A) and 1 (B), a piezoelectric element 101 obtained by the
manufacturing method of the first embodiment, which is in a stage prior to the final product, will
be described.
The illustrated piezoelectric element 101 is in a state before an electrode for exciting ultrasonic
waves is formed, and is formed of PMN-PT, PZT or other Pb-based piezoelectric material (for
example, including PMNT, PIMNT, PSMNT) It comprises a plate-like substrate 10, a threedimensional structure group 20 formed on the substrate 10 and covering one side of the
substrate 10 in a layer, and a filling part 30 filling the gap of the three-dimensional structure
group 20 and planarizing.
[0018]
The three-dimensional structure group 20 is composed of a large number of three-dimensional
structures 21 formed in a columnar shape. A number of three-dimensional structures 21 are
arranged on two-dimensional grid points along the extending XY plane of the substrate 10. Each
three-dimensional structure 21 has a quadrangular prism-like outer shape, and extends from the
substrate 10 in the Z direction perpendicular thereto. In addition, since each three-dimensional
structure 21 is formed by a dicing saw, the side surface 21 a is not necessarily a smooth surface.
[0019]
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The three-dimensional structure 21 has a smaller width (also referred to as short side length or
short side width) w1 in the cross section less than 50 μm, and a larger width (long side length,
long side in the cross section) The width h) is 10 μm to 50 μm, and the height h is 50 μm to
400 μm. That is, the aspect ratio AR = h / w1 based on the smaller short side width w1 is larger
than one. In the specific example, the short side width w1 is set to, for example, 25 μm, the long
side width w2 is set to, for example, 50 μm, and the height h is set to, for example, 100 to 120
μm.
[0020]
The filling unit 30 is formed of, for example, an epoxy resin, and supports the three-dimensional
structures 21 integrally with the multiple three-dimensional structures 21 while securing
isolation and insulation between the individual three-dimensional structures 21.
[0021]
FIGS. 2A and 2B are a plan view and a side sectional view for explaining the piezoelectric element
102 in a state in which the processing is further advanced to the piezoelectric element 101
shown in FIG. 1A and the like.
In the piezoelectric element 102 at the stage shown, the substrate 10 is removed, and a group of
first electrodes 41 and a group of second electrodes 42 are formed on the upper and lower
surfaces, respectively. The many three-dimensional structure 21 which comprises the
piezoelectric element 102 is supported by the filling part 30 via the side surface 21a. Each threedimensional structure 21 is electrically independent of the adjacent three-dimensional structure
21 and is in a state in which the interaction is unlikely to occur also in ultrasonic waves. The
group of first electrodes 41 is formed in a line and space to form a comb-like electrode 141 as a
whole, and each first electrode 41 has an upper end face 21 b of a plurality of three-dimensional
structures 21 aligned in a line in the X direction. Conductive metal thin film extending to connect
the Similarly, a group of second electrodes 42 are also formed in line and space to form a comblike electrode 142 as a whole, and each second electrode 42 has a plurality of three-dimensional
structures 21 aligned in a row in the X direction. It is a conductive metal thin film extending to
connect the lower end faces 21c. As a result, a group of three-dimensional structures 21 aligned
in the X direction constitutes a unit probe 23. In this unit probe 23, a group of three-dimensional
structures 21 connected by one first electrode 41 and a second electrode 42 opposed to the
lower side are connected in parallel to a drive circuit (not shown) provided in the final product. It
will be That is, the unit probes 23 formed of a group of three-dimensional structures 21 are
elongated in the X direction and operate uniformly upon receiving the same drive signal, but the
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three-dimensional structures 21 are columnar by dividing into multiple three-dimensional
structures 21. In this case, the vibration characteristic or the ultrasonic wave output
characteristic is better. The unit probe 23 or the first and second electrodes 41 and 42 are
present in, for example, 192 channels in the Y direction, and the unit probes 23 of these 192
channels independently receive drive signals. That is, each unit probe 23 is supplied with an
individual drive signal different in timing and the like.
[0022]
Hereinafter, a specific manufacturing method of the piezoelectric element 101 will be described
with reference to FIGS. 3 and 4 to 6 and the like.
[0023]
First, as shown in FIG. 4A, a plate-like bulk material (base material) 81 formed of PMN-PT and
having a thickness of, for example, about 0.5 mm is prepared (step S11 in FIG. 3).
[0024]
Next, as shown in FIG. 4B, on one surface of the bulk material 81, a plurality of first grooves 51
having a uniform width and extending in the Y direction are processed in parallel at equal
intervals (see FIG. Step S12 of 3).
Although the first groove 51 is formed in a part of the bulk material 81 in the drawing, the first
groove 51 can be formed in the whole of the bulk material 81, and the first groove 51 to be
formed The number can also be set appropriately according to the specification of the
piezoelectric element 101.
The first groove 51 is processed by a dicing saw (processing tool) and has a groove width of 25
μm. Also, the first grooves 51 are formed with a space period or pitch of 100 μm in the X
direction. The wedge-shaped fine shape 121 remaining between the pair of adjacent first grooves
51 is a portion to be a three-dimensional structure 21 by the subsequent processing and has a
lateral width of 75 μm. When forming the first groove 51, dicing can be performed in a state in
which the dress board is disposed adjacent to the bulk material 81. In this case, the dicing saw
can be polished while performing grooving with the dicing saw.
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[0025]
Next, as shown in FIG. 4C, a plurality of first grooves 51 formed in the bulk material 81 are filled
with the liquid reinforcing material 64 and cured to return to the original shape of the bulk
material 81. (Step S13 in FIG. 3). As the reinforcing material 64, a positive resist, a UV curable
resin, a thermosetting resin, a two-component curable resin, a wax or the like can be used. When
the reinforcing material 64 is filled, capillary action is used, a pressure is reduced for removing
air bubbles, and the viscosity of the reinforcing material is controlled by heating. Before the
reinforcing material 64 is filled, a surface treatment may be performed on the inner surface of
the first groove 51 to improve the adhesion between the reinforcing material 64 and the fine
shape 121. Furthermore, the inner surface of the first groove 51 or the surface of the fine shape
121 may be cleaned before the reinforcing material 64 is filled. As a method of cleaning the first
groove 51, for example, solvent cleaning, UV ozone cleaning, O 2 ashing, primer treatment and
the like can be performed.
[0026]
Next, as shown in FIG. 5A, on one surface of the bulk material 81, a plurality of second grooves
52 having a uniform width parallel to the plurality of first grooves 51 are processed (FIG. 5A).
Step S14 of 3). Here, the plurality of second grooves 52 are formed to extend alternately with
respect to the plurality of first grooves 51. More specifically, the second groove 52 is formed just
in the middle of the pair of adjacent first grooves 51. In other words, it can be seen that, by
means of the two sets of steps S12 and S14, a number of parallel and equally spaced grooves,
which are the final target, are formed in two steps in every other step. The second groove 52 is
processed by a dicing saw in the same manner as the first groove 51 and has a groove width of
25 μm. In addition, the second grooves 52 are formed at a pitch of 100 μm in the same manner
as the first grooves 51, and the ridge-like fine portions remaining between the adjacent first
grooves 51 and the second grooves 52 are formed. The shape 121 has a width of 25 μm in the
X direction. When the second groove 52 is formed, dicing can be performed in a state where the
dress board is disposed adjacent to the bulk material 81 as in the case of the first groove 51.
[0027]
Next, as shown in FIG. 5 (B), the liquid reinforcing material 64 is filled in the many second
grooves 52 formed in the bulk material 81 and hardened, and the external shape of the bulk
material 81 is returned to the original shape. (Step S15 in FIG. 3). The reinforcing material 64
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used in this step S15 is the same as the reinforcing material 64 used in the above step S13.
When the reinforcing material 64 is filled, capillary action is used, a pressure is reduced for
removing air bubbles, and the viscosity of the reinforcing material is controlled by heating.
Before the reinforcing material 64 is filled, surface treatment for improving the adhesion
between the reinforcing material 64 and the inner surface of the first groove 51 or the surface of
the fine shape 121 can be performed. Alternatively, the surface of the minute shape 121 can be
cleaned.
[0028]
Next, as shown in FIG. 6, on one surface of the bulk material 81, a plurality of third grooves 53
extending parallel to each other intersecting the first and second grooves 51, 52 are processed
(FIG. 2) Step S16). Here, the plurality of third grooves 53 are formed at equal intervals and
intersect with the first and second grooves 51 and 52 so as to be orthogonal to each other. The
third groove 53 is processed by a dicing saw in the same manner as the first groove 51, and has
a groove width of 25 μm in the Y direction. Further, the third grooves 53 are formed at a pitch
of 75 μm larger than the pitch 50 μm of the groove group including the first and second
grooves 51 and 52 (that is, the half pitch of the first grooves 51). The ridge-like fine features 221
remaining between the pair of adjacent third grooves 53 have a width of 50 μm in the Y
direction. When the third groove 53 is formed, dicing can be performed in a state where the
dress board is disposed adjacent to the bulk material 81 as in the case of the first groove 51. The
pitch of the third grooves 53 is larger than the half pitch of the first grooves 51 (that is, the pitch
of the combined grooves 51 and 52) as described above. The reason why the pitch of the third
grooves 53 is larger than the pitch of the combined grooves 51 and 52 is to suppress the
occurrence of breakage of the three-dimensional structure caused by the formation of the third
grooves 53. When the pitch of the third grooves 53 is equal to the pitch of the combined grooves
51, 52, the third grooves 53 may be divided into two alternating groups and processed in the
same manner as the first and second grooves 51, 52 Become desirable.
[0029]
Next, the reinforcing material 64 left on the processed bulk material 81 is removed (step S17 in
FIG. 3). The removal of the reinforcing material 64 is performed, for example, with a developing
solution when the reinforcing material 64 is formed of a positive resist, and, for example, an
organic solvent, O 2 ashing, for example, when the reinforcing material 64 is formed of another
material. As a result, a large number of three-dimensional structures 21 constituting the threedimensional structure group 20 remain on the substrate 10. A number of three-dimensional
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structures 21 are arranged on the extending two-dimensional lattice points of the substrate 10,
and each three-dimensional structure 21 has, for example, a short side width w1 of 25 μm, a
long side width w2 of 50 μm, and a height h Have a shape and size such as 100 μm.
[0030]
Thereafter, as shown in FIG. 1B, the gaps between the three-dimensional structures 21 (that is,
the grooves 51, 52, 53) are filled with an epoxy resin or other filler and cured to form the filling
portion 30 (step of FIG. 3) S18). Thereby, the piezoelectric element 101 at the first stage shown
in FIG. 1A and the like is completed.
[0031]
Although the detailed description will be omitted for the subsequent steps, the substrate 10 is
first removed by grinding or polishing, and the upper end face 21b of the three-dimensional
structure 21 and the lower side will be described first simply by referring to FIG. The end face
21c is exposed. That is, a composite piezoelectric element layer 120 in which a number of threedimensional structures 21 are two-dimensionally arranged is obtained. Then, a metal thin film
pattern of a plurality of rows of first electrodes 41 extending so as to connect the upper end
faces 21 b of the series of three-dimensional structures 21 is formed by a photoresist or other
method to obtain the comb-like electrodes 141. Similarly, metal thin film patterns of a plurality of
rows of second electrodes 42 extending so as to connect the series of lower end faces 21c of the
three-dimensional structure 21 are formed by a photoresist or other method to obtain the comblike electrodes 142. Thereby, the piezoelectric element 102 at the second stage shown in FIGS.
2A and 2B is completed.
[0032]
FIG. 7A is a view for explaining a modified example of the method of processing the first groove
51 and the second groove 52. In this case, the first groove 51 and the second groove 52 are not
cut out so as to cross the bulk material 81, but are processed halfway to the length direction.
That is, instead of cutting the dicing saw from one end of the bulk material 81 to the other end,
the dicing saw is retracted from the bulk material 81 halfway to the other end to interrupt
cutting. As a result, the unprocessed region 82 remains in the bulk material 81, and the shallow
halfway region 84 is formed on the unprocessed region 82 side of the first and second grooves
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51 and 52. In this case, since the wedge-shaped fine features 86 remaining between the first and
second grooves 51 and 52 are in a state of being connected to each other via the unprocessed
region 82 and the like, stress from the dicing saw acting on this It can prevent that it is damaged.
In the case where the second groove 52 is processed after the completion of the processing of all
the first grooves 51 as in the present embodiment, the dicing saw protrudes from the bulk
material 81 just before the completion of the processing of the second groove 52 and is covered.
As the amount of metal being reduced is small, there is a circumstance that the rotation of the
dicing saw is distorted especially when the pitch of the grooves 51 and 52 is narrow, and the fine
shape 86 around the second groove 52 tends to be broken. Providing 82 mag is an effective
measure.
[0033]
FIG. 7B is a view for explaining another modified example of the processing method of the first
groove 51 and the second groove 52. In this case, when forming the first groove 51 and the
second groove 52, the bulk material 81 is not cut out and not only processed halfway, but the
second groove 52 is opposite to the first groove 51. Advance the processing from the direction.
As a result, in the bulk material 81, the one-sided processed areas 88 remain at both ends. In this
case, the target portion (that is, the single-piece processing area 88) becomes thick at the start of
processing of the second groove 52, and the wedge-shaped fine shape 86 can be effectively
prevented from being damaged by the stress from the dicing saw acting thereon. . When the
processing of the second groove 52 is started, the pitch of the grooves 51 and 52 is particularly
narrow because the amount by which the dicing saw protrudes from the bulk material 81 and is
covered even if the reinforcing material 64 is present. In this case, there is a circumstance that
the rotation of the dicing saw is distorted and the fine shape 86 around the second groove 52 is
likely to be damaged, and the processing of the second groove 52 is in the opposite direction to
the processing of the first groove 51. It is an effective measure to proceed from the
[0034]
FIGS. 8A and 8B are diagrams for explaining a specific processing example, showing a state in
which the reinforcing material 64 has been removed after the step shown in FIG. 5B. FIG. 8 (A)
shows an SEM image of a plan view, and FIG. 8 (B) shows an SEM image of a cross section. In this
processing example, the rotation speed of the dicing saw is 30000 rpm, and the feed rate is 1
mm / s. As apparent from the figure, in the case of the specific processing example, the portion
corresponding to the fine shape 121 shown in FIG. 5B is periodically formed cleanly, and there is
no chip. 8 (C) and 8 (D) are diagrams for explaining a processing example of comparison, and
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show a state in which the shape shown in FIG. 5 (B) is collectively performed. That is, the second
groove 52 is formed without being filled with the reinforcing material 64 after the formation of
the first groove 51. As apparent from the figure, in the case of the comparative processing
example, the portion corresponding to the minute shape 121 shown in FIG. 5B has a chip at a
plurality of places.
[0035]
FIG. 9 is a view for explaining a probe for an ultrasonic inspection apparatus manufactured using
the piezoelectric element 102 shown in FIG. 2A and the like. The illustrated probe 90 operates
the vibrating portion 91 obtained from the piezoelectric element 102, the backing material 92
disposed behind the vibrating portion 91, the matching layer 93 disposed on the front surface of
the vibrating portion 91, and the vibrating portion 91. The drive circuit 94 is provided. The
piezoelectric element 102 constituting the vibrating portion 91 has a composite piezoelectric
element layer 120 and comb-like electrodes 141 and 142 sandwiching the composite element
layer 120 from above and below. One of the comb-like electrodes 141 is, for example, a plus
electrode, and is connected to the ribbon-like parallel wiring 98 a in units of individual first
electrodes 41, and the other comb-like electrode 142 is, for example, a minus electrode. The
second electrodes 42 are connected to the ribbon-shaped parallel wiring 98 b in units of units.
Both parallel wires 98a and 98b extend from the drive circuit 94 and extend to the unit probes
23 corresponding to the respective channels (ie, the pair of first and second electrodes 41 and
42 and a number of three-dimensional structures 21 therebetween). The voltage of the period
corresponding to the sound wave is applied to generate ultrasonic vibration in a number of threedimensional structures 21 constituting the ultrasonic wave, and the ultrasonic vibration received
by the many three-dimensional structures 21 is converted into a voltage signal. The backing
material 92 prevents the ultrasonic waves from being radiated to the rear of the vibrating portion
91. In addition, the matching layer 93 has a role of adjusting the wave front of the ultrasonic
wave emitted forward of the vibrating portion 91.
[0036]
In the specific operation of the probe 90, an ultrasonic wave transmission operation performed
in a nanosecond to microsecond period and an ultrasonic wave reception operation performed in
a similar period are alternately repeated. In the transmission operation, the drive circuit 94
receives a trigger signal from a control circuit (not shown) and causes ultrasonic vibration with a
predetermined delay time set in each unit probe 23 constituting the probe 90. In the reception
operation, the drive circuit 94 receives a voltage signal corresponding to the reflection of the
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ultrasonic wave detected by each unit probe 23 and combines the signals in a predetermined
delay time set in each unit probe 23. This makes it possible to control the wave front of the
ultrasonic wave, and it is possible to apply an ultrasonic wave of a desired frequency toward the
point-like object in front of the probe 90, and it is reflected back from the point-like object.
Ultrasonic waves can be selectively received.
[0037]
In the method of manufacturing the piezoelectric elements 101 and 102 according to the first
embodiment described above, a plurality of second widths having a uniform width with respect
to the bulk material 81 filled with the reinforcing material 64 and extending parallel to the first
grooves Since the grooves 52 are processed, it is possible to obtain a three-dimensional structure
group 20 which is formed at an interval narrower than the first grooves 51. At this time, the fine
shape 121 formed between the first groove 51 before forming the second groove 52 is one size
larger than the fine shape 121 after the processing of the second groove 52, and chipping and
deterioration are caused. It becomes relatively easy to form the non-fine shape 121. Furthermore,
since the plurality of second grooves 52 are processed with respect to the bulk material 81 filled
with the reinforcing material 64, it is possible to relatively easily obtain the three-dimensional
structure 21 of the target width while avoiding damage due to processing. .
[0038]
Second Embodiment A method of manufacturing a piezoelectric element according to the second
embodiment will be described below. The manufacturing method of the second embodiment is a
partial modification of the manufacturing method of the first embodiment, and items not
particularly described are the same as the manufacturing method of the first embodiment.
[0039]
With reference to FIG. 10 etc., the manufacturing method by 2nd Embodiment of the
piezoelectric element 101 shown to FIG. 1 (A) etc. is demonstrated.
[0040]
Preparation of bulk material (base material) 81 (step S21 of FIG. 10), processing of first groove
51 (step S22 of FIG. 10), and filling of reinforcing material 64 into first groove 51 (step of FIG.
10) The steps up to S23) are the same as the steps S11 to S13 of FIG.
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[0041]
Thereafter, as shown in FIG. 11, before forming the plurality of second grooves 52 in the bulk
material 81, the plurality of third grooves 53 extending in parallel with each other and crossing
the first grooves 51 are formed. It processes (process S24 of FIG. 10).
[0042]
Next, as shown in FIG. 12, without filling the third groove 53 with the reinforcing material 64,
the bulk material 81 has a large number of parallel uniform widths parallel to the multiple first
grooves 51. The second groove 52 is processed (step S25 in FIG. 10).
[0043]
Thereafter, the reinforcing material 64 left on the processed bulk material 81 is removed (step
S26 in FIG. 10), and the gaps between the three-dimensional structure 21 are filled with an
epoxy resin or other filler to form the filling portion 30 (FIG. 10). Step S27).
[0044]
As mentioned above, although the manufacturing method of the piezoelectric element as an
embodiment was explained, the manufacturing method of the piezoelectric element concerning
the present invention is not restricted to the above-mentioned thing.
For example, specific examples of the short side width, the long side width, and the height of the
three-dimensional structure 21 are merely examples, and can be arbitrarily set within the scope
of the claims.
[0045]
Further, the arrangement of the three-dimensional structure 21 in the three-dimensional
structure group 20 is not limited to the illustrated one, and can be set variously according to the
application.
[0046]
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In the above, although a number of grooves arranged in parallel at equal intervals as the final
target are formed in two steps every other one by two steps of steps S12 and S14, the present
invention is limited to this Absent.
That is, it is possible to form a number of grooves arranged in parallel and equally spaced apart
as a final target in two or more steps at every two or more intervals.
[0047]
Although the thing formed in columnar shape as the three-dimensional structure 21 was
illustrated above, a wall-like thing can also be used as the three-dimensional structure 21. FIG.
For example, when the preparation of the three-dimensional structure group 20 is finished at the
stage of FIG. 5A and the reinforcing material is removed, the wall-like or bowl-like fine shape 121
remains, and this wall-like fine shape 121 is used as a three-dimensional structure. be able to.
The piezoelectric element 102 shown in FIG. 13 includes a composite piezoelectric element layer
120 in which a number of wall-shaped three-dimensional structures 321 are arranged in one
dimension.
The composite piezoelectric element layer 120 includes a plurality of wall-shaped threedimensional structures 321 as the three-dimensional structure group 20, and the gaps formed
between the adjacent wall-shaped three-dimensional structures 321 are filled by the filling unit
30.
The composite piezoelectric element layer 120 shown in FIG. 5 removes the reinforcing material
64 from the bulk material 81 in the state shown in FIG. 5A and fills the grooves 51 and 52 with a
filling material to form the filling portion 30 and the substrate 10. It is obtained by removing. As
indicated by dotted lines in the composite piezoelectric element layer 120, the first electrode 41
and the second electrode 42 are formed on the upper end surface 221b and the lower end
surface 221c of each three-dimensional structure 321 extending in a wall shape. Do. Thereby,
the piezoelectric element 102 is completed.
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[0048]
DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 20 ... Three-dimensional structure group, 21
321 ... Three-dimensional structure, 21a ... Side surface, 21b ... Upper end surface, 21c ... Lower
end surface, 23 ... Unit probe, 30 ... Filling part, 41, 42 ... Electrode 51, The 51st 1 groove, 52
second groove, 53 third groove 64 reinforcement material 81 bulk material 86 fine shape 90
probe 91 vibration portion 92 backing material 93 alignment Layers 94 Drive circuits 98a and
98b Both parallel wiring 101 and 102 Piezoelectric elements 120 Composite piezoelectric
element layers 121 and 221 Fine shapes 141 and 142 comb-like electrodes
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17
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