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DESCRIPTION JP2009295865

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DESCRIPTION JP2009295865
An object of the present invention is to provide a piezoelectric speaker capable of satisfactorily
reproducing bass. SOLUTION: A honeycomb type piezoelectric / electrostrictive element 100 in
which an internal electrode 5b is divided into a plurality of parts among internal electrodes 5a,
5b arranged as a pair with a partition interposed therebetween is used as a speaker. [Selected
figure] Figure 2
Honeycomb type piezoelectric / electrostrictive element and piezoelectric / electrostrictive
speaker using the same
[0001]
The present invention relates to a honeycomb type piezoelectric / electrostrictive element and a
piezoelectric / electrostrictive speaker using the same.
[0002]
In recent years, piezoelectric speakers have become widespread.
This piezoelectric speaker is a speaker using a resonance phenomenon that piezoelectric ceramic
develops, and is characterized by being thinner and smaller in power consumption than a
conventional dynamic type speaker.
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[0003]
On the other hand, in complex portable devices, there is a demand for slimming with an
emphasis on design, improvement in sound quality at the time of music reproduction and
television viewing, and prolongation of battery life. Therefore, the piezoelectric speaker having
the above-mentioned features is in widespread use particularly for portable devices.
[0004]
However, the piezoelectric speaker composed of the conventional planar piezoelectric diaphragm
is significantly inferior to the dynamic type speaker in volume and sound quality. In particular,
due to the characteristics described above, it is difficult to faithfully reproduce the bass region to
the original sound. Therefore, in order for the piezoelectric speaker to expand the market, it is
necessary to match the sound quality to the market requirements.
[0005]
The present invention has been made in view of such circumstances, and an object thereof is to
provide a piezoelectric speaker capable of satisfactorily reproducing bass. As a result of repeated
research, it has been found that this problem is solved by the following means.
[0006]
That is, first, according to the present invention, a columnar honeycomb structure formed by
dividing and forming a plurality of cells penetrating in the axial direction is disposed so as to
cover the surface of the partition wall. A honeycomb type piezoelectric / electrostrictive element
in which at least one of the internal electrodes arranged in a pair with the partition wall
interposed therebetween is divided into a plurality of portions in the axial direction. Be done.
[0007]
In the honeycomb type piezoelectric / electrostrictive element according to the present invention,
it is preferable that all of the plurality of cells be plugged at the same one end.
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In this case, adjacent ones of the plurality of cells are alternately plugged at the other end
opposite to the one end, and the internal electrode divided into the plurality of portions in the
axial direction is An internal electrode, which is disposed on the surface of a partition which is
plugged at one end and is plugged at the other end, is divided into a plurality of parts in the axial
direction to be a power supply The wiring to be connected is preferably laid in a cell plugged at
one end and plugged at the other end.
[0008]
In the above preferred embodiment, all of the plurality of cells are plugged at the same one end,
and adjacent cells of the plurality of cells are alternately plugged at the other opposite end. At
the other end, adjacent cells will be alternately open (not plugged).
[0009]
In the honeycomb-type piezoelectric / electrostrictive element according to the present invention,
it is preferable that the cross-sectional shape perpendicular to the longitudinal direction of the
cell is a quadrangle in which the corner portion is arc-shaped.
[0010]
In the honeycomb-type piezoelectric / electrostrictive device according to the present invention,
the honeycomb structure portion is obtained by firing a honeycomb formed body obtained by
extrusion-forming a forming material containing a piezoelectric / electrostrictive material as a
main component. preferable.
Alternatively, in the honeycomb type piezoelectric / electrostrictive device according to the
present invention, the honeycomb structure portion is obtained by firing a honeycomb formed
body obtained by laminating green sheets containing a piezoelectric / electrostrictive material as
a main component. preferable.
[0011]
Next, according to the present invention, using the partition as a diaphragm, using the cell as a
traveling wave forming space, and using any of the above-mentioned honeycomb type
piezoelectric / electrostrictive elements to generate sound from the end of the cell An
electrostrictive speaker is provided.
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[0012]
The piezoelectric / electrostrictive speaker according to the present invention is a honeycombtype piezoelectric / electrostrictive device in which at least one of the internal electrodes
disposed in a pair across the partition wall is divided into a plurality of portions in the axial
direction. Since it is used, the partition walls of the honeycomb type piezoelectric /
electrostrictive element can be deformed (pulsating) so that a traveling wave is formed in the cell.
It is then possible to generate a sound from the open cell.
Therefore, it is easier to generate a sound wave with a lower frequency than a piezoelectric
speaker composed of a conventional planar piezoelectric diaphragm. Further, since the sound
wave has strong directivity in the longitudinal direction (axial direction) of the cell, it is suitable
as a speaker with high directivity.
[0013]
In the piezoelectric / electrostrictive speaker according to the present invention, in a preferred
embodiment, a cell in which internal electrodes divided into a plurality of portions in the axial
direction are plugged at one end and the other end A wire which is disposed on the surface of the
partition wall to form the inner wall and which connects the internal electrode divided into a
plurality of portions in the axial direction to the power supply is plugged at one end thereof and
an eye at the other end Since the honeycomb type piezoelectric / electrostrictive element laid in
the cell to be sealed is used, the cell for wiring and the cell for forming the traveling wave can be
distinguished. Therefore, the wiring becomes easy, noise is less likely to occur, and the sound
quality is improved.
[0014]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe
embodiments of the present invention as needed, referring to the drawings, but the present
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invention should not be construed as being limited thereto. Various changes, modifications,
improvements, and substitutions can be added based on the knowledge of those skilled in the art
without departing from the scope of the present invention. For example, the drawings show
preferred embodiments according to the present invention, but the present invention is not
limited by the embodiments shown in the drawings and the information shown in the drawings.
In carrying out or verifying the present invention, means similar or equivalent to those described
herein may be applied, with the preferred means being the means described hereinafter.
[0015]
FIGS. 1A and 1B are views schematically showing one embodiment of a honeycomb-type
piezoelectric / electrostrictive element according to the present invention. FIG. 1A is a
perspective view, and FIG. 1B is a perspective view in which “part A” of FIG. 1A is cut out and
enlarged. FIG. 2 is a cross-sectional view schematically showing another embodiment of the
honeycomb type piezoelectric / electrostrictive element according to the present invention, and
is a view showing a cross section parallel to the axial direction.
[0016]
The honeycomb type piezoelectric / electrostrictive element 100 shown in FIG. 1A and FIG. 1B
has a columnar honeycomb structure portion 1 having partition walls 3 for forming a plurality of
cells 2 penetrating in the axial direction (central axis direction) P; The inner wall surface 4 of the
cell 2 is provided with an internal electrode 5 disposed so as to cover the entire inner wall
surface 4 from the inside. The inner wall surface 4 of the cell 2 is the surface of the partition 3
forming the cell 2, and the partition 3 is a piezoelectric / electrostrictive body. Further, as shown
in FIG. 2, in the honeycomb type piezoelectric / electrostrictive element 100, one of the internal
electrodes 5 (internal electrodes 5a and 5b) disposed in a pair with the partition wall 3
interposed therebetween. The internal electrode 5b, which is the above, is divided into a plurality
of portions in the axial direction P.
[0017]
The honeycomb type piezoelectric / electrostrictive element 300 shown in FIG. 2 is obtained by
plugging the cells of the honeycomb type piezoelectric / electrostrictive element 100. In the
honeycomb type piezoelectric / electrostrictive element 300, all the cells 2 of the honeycomb
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type piezoelectric / electrostrictive element 100 are plugged by the plugging portion 11 at the
same one end (the end on the left side in FIG. 2) Adjacent ones of the cells 2 are alternately
plugged by the plugging portion 11 at the other end (the end on the right side in FIG. 2) opposite
to one end. The internal electrode 5b divided into a plurality of portions is disposed on the
surface (inner wall surface 4) of the partition 3 forming the cell 2 plugged at both ends and
divided into a plurality of portions. The internal electrode 5a which is not provided is disposed on
the surface (inner wall surface 4) of the partition 3 forming the cell 2 in which only one end (left
side) is plugged.
[0018]
The honeycomb type piezoelectric / electrostrictive element 100 (or a portion corresponding to
the honeycomb type piezoelectric / electrostrictive element 100 included in the honeycomb type
piezoelectric / electrostrictive element 300) is disposed in the adjacent cell 2 with the partition 3
interposed therebetween. It is possible to apply a voltage between the electrodes 5 (5a, 5b) to
deform the partition walls 3 and thus to deform the honeycomb structure portion 1. When a
voltage is applied between the internal electrodes 5a and 5b disposed with the partition 3 in
between, the partition 3 extends in the thickness direction (direction d33) and shrinks in the
direction perpendicular to the thickness direction (direction d31) It is possible to deform.
[0019]
As shown in FIG. 1B, since the central axis direction P of the honeycomb type piezoelectric /
electrostrictive element 100 corresponds to the direction perpendicular to the thickness
direction of the partition 3, the partition 3 is in the direction indicated by the arrows a1 and a2.
Deform to shrink. Also in the direction (end face and cross section) perpendicular to the central
axis direction P of the honeycomb type piezoelectric / electrostrictive element 100, the partition
3 is shown by arrows a3 and a4 also in the direction perpendicular to the thickness direction of
the partition 3. It deforms so as to shrink in the direction and in the direction indicated by arrows
a5 and a6. Furthermore, in the thickness direction of the partition 3 in the plane (end face and
cross section) perpendicular to the central axis direction P of the honeycomb type piezoelectric /
electrostrictive element 100, the partition 3 extends in the direction indicated by the arrows a7
and a8. Deform. Thus, the partition 3 extends in its thickness direction and deforms so as to
shrink in a direction perpendicular to the thickness direction.
[0020]
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Therefore, for example, if a voltage is applied to the divided internal electrodes 5b at the same
timing, the partition 3 deforms the same at any part, so that the honeycomb-type piezoelectric /
electrostrictive element 100 generally becomes a cell 2 Shrink in the penetrating direction
(central axis direction P), and further in a plane perpendicular to the penetrating direction of the
cell 2 (central axis direction P). The partition 3 is deformed so as to extend in the thickness
direction, but since the space of the cell 2 is formed in the thickness direction of the partition 3,
the deformation in the thickness direction of the partition 3 narrows the space of the cell 2 Thus,
the contribution to the change of the external shape of the honeycomb type piezoelectric /
electrostrictive element 100 is small.
[0021]
On the other hand, if voltages are applied to the divided internal electrodes 5b at different
timings, the timing of deformation of the partition 3 sandwiched by the respective internal
electrodes 5b to which the voltages are applied at different timings also deviates. Alternatively, if
voltages having different waveforms are applied to the divided internal electrodes 5b, the
partitions 3 sandwiched by the respective internal electrodes 5b are similarly deformed at
different timings according to the waveform of the voltage. Therefore, by applying such a
voltage, it is possible to make the partition 3 pulsate instead of shrinking the honeycomb type
piezoelectric / electrostrictive element 100 as a whole.
[0022]
These effects are similarly exhibited in the honeycomb type piezoelectric / electrostrictive
element 300 configured by the honeycomb type piezoelectric / electrostrictive element 100.
Therefore, the honeycomb type piezoelectric / electrostrictive element 100, 300 is used as a
piezoelectric / electrostrictive speaker that generates sound from the end of the cell 2 using the
partition 3 as a diaphragm and the cell 2 as a traveling wave forming space You can do it. In
particular, since only one end of the cell 2 is open, the honeycomb-type piezoelectric /
electrostrictive element 300 is suitable as a speaker with high directivity.
[0023]
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The outer peripheral wall 6 is disposed so as to surround the entire outermost periphery of the
partition 3 in the honeycomb structure portion 1 constituting the honeycomb type piezoelectric /
electrostrictive element 100, 300. The partition 3 is a piezoelectric / electrostrictive body, but
the outer peripheral wall 6 may be a piezoelectric / electrostrictive body, or may be another
ceramic material.
[0024]
The size of the honeycomb type piezoelectric / electrostrictive element 100, 300 can be
appropriately selected depending on the application. For example, in the case of using as a
piezoelectric / electrostrictive speaker, it is preferable that the cross-sectional area is about 0.3 to
1.5 mm <2> and the length is about 30 to 80 mm.
[0025]
The thickness of the partition 3 of the honeycomb type piezoelectric / electrostrictive element
100, 300 can be appropriately selected depending on the application. For example, when used as
a piezoelectric / electrostrictive speaker, it is preferably 20 to 500 μm, more preferably 30 to
80 μm, and particularly preferably 30 to 50 μm. Moreover, when it has the outer peripheral
wall 6, it is preferable that the thickness is 50-200 micrometers.
[0026]
The number of cells 2 formed in the honeycomb type piezoelectric / electrostrictive element 100,
300 can be appropriately selected depending on the application. For example, when using as a
piezoelectric / electrostrictive speaker, 10-1000 are preferable and 40-500 are still more
preferable.
[0027]
In the honeycomb type piezoelectric / electrostrictive element 100, 300, the shape of the cross
section perpendicular to the central axis of the honeycomb structure part 1 may be a quadrangle
as shown in FIG. 1A, but other multiple polygons such as pentagons and hexagons It may be
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square, or may be another shape such as a circle, an oval, or a track shape. The cross-sectional
shape perpendicular to the central axis of the cell 2 (perpendicular to the longitudinal direction)
may be a quadrangle as shown in FIG. 1A, but may be another polygon such as a pentagon or a
hexagon. Alternatively, the shape may be another shape such as a polygon such as a quadrilateral
having a corner portion in an arc shape, a circle, an ellipse, a track shape, or the like. When
saying "a square whose corner is arc-shaped", in the cross-sectional shape perpendicular to the
longitudinal direction of the cell 2, it is a square in which four corners (portions corresponding to
apexes) are rounded in an arc. Say Such a shape of the cell is preferable in that the electric field
concentration of the portion corresponding to the corner of the internal electrode disposed in the
cell can be prevented.
[0028]
In the honeycomb-type piezoelectric / electrostrictive elements 100 and 300, the honeycomb
structure portion 1 is preferably formed by firing a material obtained by extrusion molding of a
forming material containing a piezoelectric / electrostrictive material as a main component. As a
result, the honeycomb type piezoelectric / electrostrictive element 100, 300 can be efficiently
manufactured in a small number of steps, and the manufacturing cost can be reduced.
Alternatively, the honeycomb structure portion 1 may be formed by firing a laminate of green
sheets containing a piezoelectric / electrostrictive material as a main component. Here, the
phrase "piezoelectric / electrostrictive material is the main component" means that the content of
the piezoelectric / electrostrictive material with respect to the entire powder component
constituting the forming raw material exceeds 50% by mass.
[0029]
In the honeycomb type piezoelectric / electrostrictive element 100, 300, the thickness of the
internal electrode 5 can be appropriately selected depending on the application. For example,
when used as a piezoelectric / electrostrictive speaker, it is preferably 0.05 to 5 μm, more
preferably 0.1 to 1 μm, and particularly preferably 0.1 to 0.5 μm . If the thickness is less than
0.05 μm, the resistance of the electrode may be high, the electric field may not be applied to the
piezoelectric / electrostrictive body.
[0030]
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In the honeycomb type piezoelectric / electrostrictive element 300, the circuit for connecting the
internal electrode 5 to the power supply can be configured by the plugging portion 11 for the
undivided internal electrode 5a. That is, the plugging portions 11 are formed of a conductive
material, and the plugging portions 11 are connected to each other on the side (left side in FIG.
2) in which all the cells 2 are plugged. The electrode 5a may be connected (see FIG. 2), and the
plugging portion 11 may be connected to a power supply. With regard to the divided internal
electrodes 5b, as shown in FIG. 2, the sealed interconnections 12 are connected to the respective
internal electrodes 5b, and the interconnections 12 are connected to the power supply by
penetrating the plugging portions 11. It is possible. In this case, the wiring 12 connecting the
internal electrode 5 b to the power supply is laid in the cell 2 whose both ends are plugged by
the plugging portion 11.
[0031]
In the honeycomb type piezoelectric / electrostrictive element 100 in which the plugging portion
11 does not exist, an external electrode may be formed of a conductive material, and the internal
electrode 5a may be connected thereto. Also in the honeycomb type piezoelectric /
electrostrictive element 300, the plugging portion 11 is formed of, for example, the same
piezoelectric / electrostrictive material as the partition 3 and the plugging portion 11 is made to
be insulating. An external electrode may be formed of a conductive material, and the internal
electrode 5a may be connected thereto.
[0032]
In the honeycomb type piezoelectric / electrostrictive element 300, the depth (the length of
penetration into the cell 2) of the plugged portion 11 can be appropriately set depending on the
application. For example, when using as a piezoelectric / electrostrictive speaker, 0.5-5 mm is
preferable. When used as a piezoelectric / electrostrictive speaker, it is preferable that the
plugging portion 11 be disposed so as to completely close the hole of the cell 2.
[0033]
In the honeycomb-type piezoelectric / electrostrictive element 300, if the plugging portion 11 is
made dense, there is an advantage that it is possible to exclude external moisture and the like
that adversely affect the durability of the element. On the other hand, in the case of the porous
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material, since there is air permeability inside and outside of the cell, there is an advantage that
the reliability against the pressure change of the outside is high. When used as a piezoelectric /
electrostrictive speaker, the plugging portion 11 is preferably dense.
[0034]
When the external electrode is provided, the thickness can be appropriately selected depending
on the application. For example, when using it as a piezoelectric / electrostrictive speaker, 0.1-20
micrometers is preferable.
[0035]
Next, the material of the honeycomb type piezoelectric / electrostrictive element according to the
present invention will be described.
[0036]
The partition walls 3 of the honeycomb structure portion 1 constituting the honeycomb type
piezoelectric / electrostrictive elements 100 and 300 are piezoelectric / electrostrictive bodies.
The piezoelectric / electrostrictive material constituting the piezoelectric / electrostrictive body is
not particularly limited as long as it is a material that causes electric field induced distortion, and
may be crystalline or amorphous, and may be a semiconductor ceramic material or a strong
material. It may be a dielectric ceramic material or an antiferroelectric ceramic material. It may
be appropriately selected and adopted according to the application. Further, the material may or
may not require a polarization treatment.
[0037]
Specifically, lead zirconate, lead titanate, lead magnesium niobate, lead nickel niobate, lead nickel
tantalate, lead zinc niobate, lead manganese niobate, lead antimony niobate, lead manganese
tungstate, cobalt niobium Lead acid, lead magnesium, lead magnesium tungstate, lead
magnesium magnesium tantalate, barium titanate, sodium bismuth titanate, bismuth neodymium
titanate (BNT), sodium niobate, potassium sodium niobate, strontium bismuth tantalate, barium
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barium copper tungsten, ferrate Bismuth or a composite oxide of two or more of them can be
mentioned. Further, these materials include lanthanum, calcium, strontium, molybdenum,
tungsten, barium, niobium, zinc, nickel, manganese, cerium, cadmium, chromium, cobalt,
antimony, iron, yttrium, tantalum, lithium, bismuth, tin, An oxide such as copper may be solidsolved. Among them, materials containing nickel oxide mainly composed of complex oxide of lead
zirconate, lead titanate and lead magnesium niobate, lead zirconate, lead titanate, lead
magnesium niobate, lead nickel niobate Materials based on complex oxides are preferred because
large electric field induced strain can be used. Here, the main component means a component
having a content of more than 50% by mass. In this case, as the nickel component, one
containing 0.05 to 3% by mass in terms of oxide is particularly preferable. Further, materials
obtained by adding lithium bismuthate, lead germanate or the like to the above materials are
preferable because they can exhibit high material properties while realizing low-temperature
firing of the piezoelectric / electrostrictive body, and in particular, the above lead zirconates and
titanium are preferable. A material comprising nickel oxide as a main component of a complex
oxide of lead acid and magnesium lead niobate, containing 0.05 to 3% by mass in terms of oxide
as the nickel component, and germanium acid A material containing 0.3 to 4% by mass of lead
added and a composite oxide of lead zirconate, lead titanate, lead magnesium niobate, and lead
nickel niobate as its main component Preferably, the material contains 0.05 to 3% by mass in
terms of oxide, and 0.3 to 4% by mass of lead germanate is added.
[0038]
The internal electrode 5 is preferably made of a conductive metallic material which is solid at
room temperature. For example, a single metal or alloy containing aluminum, titanium,
chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver,
tin, tantalum, tungsten, iridium, platinum, gold, lead and the like It can be mentioned.
[0039]
When the external electrode is provided, the material is preferably made of a conductive metal
which is solid at room temperature. For example, a single metal or alloy containing aluminum,
titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium,
rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead and the like It can be
mentioned.
[0040]
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The material of the plugging portion is preferably one that is solid at room temperature and
contains a conductive metal. For example, a single metal or alloy containing aluminum, titanium,
chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver,
tin, tantalum, tungsten, iridium, platinum, gold, lead and the like It can be mentioned.
[0041]
Next, a method of manufacturing a honeycomb-type piezoelectric / electrostrictive element
according to the present invention will be described. The honeycomb type piezoelectric /
electrostrictive device according to the present invention can be manufactured, for example, by
the following method, but the method of manufacturing the honeycomb type piezoelectric /
electrostrictive device according to the present invention is limited to the following method. It
will not be done. Here, a method of manufacturing the honeycomb type piezoelectric /
electrostrictive element 300 will be described.
[0042]
First, a clay for forming the honeycomb structure portion 1 is formed. This uses the raw material
of what was mentioned as a material of the partition 3 of the honeycomb structure part 1
mentioned above, mixes and kneads the raw material, and forms clay. For example, water, a
dispersion medium such as an organic solvent, an organic binder, a dispersant and the like are
added to a powder raw material such as lead zirconate titanate to make a forming raw material,
and this is kneaded to form clay clay.
[0043]
As an organic binder, hydroxypropyl methylcellulose, methylcellulose, hydroxyethyl cellulose,
carboxyl methylcellulose, polyvinyl alcohol and the like can be used. These may be used singly or
in combination of two or more. As a dispersing agent, ethylene glycol, made string, fatty acid
soap, polyalcohol etc. can be used. These may be used singly or in combination of two or more.
When an organic solvent is used as the dispersion medium, it is preferable to use an organic
solvent such as alcohol. As an organic solvent, terpineol can be used, for example. In this case,
polyvinyl butyral can also be used as the organic binder. There is no restriction | limiting in
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particular as a method of knead | mixing a shaping | molding raw material and preparing clay,
For example, the method of using a kneader, a vacuum soil kneader, etc. can be mentioned.
[0044]
Next, the obtained clay is formed into a honeycomb shape to produce a honeycomb formed body.
There is no restriction | limiting in particular as a method to produce a honey-comb molded
object, Conventionally well-known shaping | molding methods, such as extrusion molding,
injection molding, press molding, can be used. Among them, a method of extruding the clay
prepared as described above using a die having a desired cell shape, partition wall thickness and
cell density can be mentioned as a preferable example. In addition, a slurry is prepared by mixing
the raw material and an organic solvent containing a binder, and the slurry is formed by a doctor
blade method or the like to obtain a green sheet provided with a plurality of through holes for
forming cells. A honeycomb formed body may be produced by laminating the green sheets.
[0045]
Next, the obtained honeycomb molded body is preferably dried to produce a honeycomb dried
body. The drying method is also not particularly limited, and for example, conventionally known
drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure
drying, vacuum drying, lyophilization and the like can be used. Among them, a drying method
combining hot air drying with microwave drying or dielectric drying is preferable in that the
entire formed body can be dried quickly and uniformly.
[0046]
Next, the obtained honeycomb dried body may be calcined before main firing to prepare a
calcined body. The “calcination” means an operation of burning and removing an organic
substance (organic binder, dispersant, etc.) in the honeycomb formed body. The calcination
temperature may be about 200 to 800 ° C. The calcination time is not particularly limited, but is
usually about 10 to 100 hours.
[0047]
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Next, the honeycomb structure body 1 can be obtained by firing (main firing) the obtained
calcined body. "Main firing" means an operation for sintering and densifying the forming raw
material in the calcined body to secure a predetermined strength. The firing conditions
(temperature and time) vary depending on the type of forming raw material, and therefore,
appropriate conditions may be selected according to the type.
[0048]
Next, the internal electrodes 5 (5a, 5b) are disposed on the inner wall surface 4 (the surface of
the partition 3) of the cells 2 of the honeycomb structure part 1. The internal electrode 5 a is
disposed on the entire inner wall surface 4, and the internal electrode 5 b is disposed on the
inner wall surface 4 by being divided into a plurality. As a method of arranging the internal
electrode 5, for example, it can be arranged by the following method. First, the metal to be the
material of the internal electrode 5 is powdered, and a solvent such as alcohol or an organic
binder is added to form a slurry. As a slurry concentration, 50-80 mass% is preferable. Moreover,
as a viscosity of a slurry, 0.05-50 Pa.s is preferable. Then, in the case of the internal electrode 5a,
the honeycomb structure portion 1 is immersed in the slurry to attach the slurry to the inner wall
surface 4 of the cell 2 and then heated at 600 to 900 ° C. A film-like internal electrode 5a can
be disposed to cover it. In this case, when the slurry is attached to the inner wall surface 4 of the
cell 2, it is preferable that the slurry be efficiently attached to the inner wall surface 4 of the cell
2 by suction from the partition wall side. In the case of the internal electrode 5b, after a material
to be a mask is attached to a portion where the electrode is not formed, a slurry is attached to the
inner wall surface 4 of the cell 2 in the same manner as the internal electrode 5a. Besides the
above methods, plating, sputtering and the like are also used.
[0049]
Next, the plugging portion 11 is disposed on one end face of the honeycomb structure portion 1
in which the internal electrode 5 (5a, 5b) is disposed. The method for arranging the plugging
portion 11 is, for example, as follows. First, a plugging slurry (or plugging paste) containing
powder of metal raw material used for the plugging portion 11, an organic solvent such as water
or alcohol, and an organic binder is stored in a storage container. . As a slurry concentration, 5090 mass% is preferable. Moreover, as viscosity of a slurry, 5-5000 Pa.s is preferable. Then, one
end of the honeycomb structure portion 1 in which the internal electrode 5 is disposed is
immersed in the storage container, and the opening portion of the cell 2 is filled with the
plugging slurry to form the plugging portion 11 Do. When there are cells 2 in which the plugging
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portions 11 are not provided, the cells 2 in which the plugging portions 11 are not provided may
be masked among the cells at the respective end portions.
[0050]
The wire 12 is inserted by inserting a coated lead wire with solder at its tip from the end face of
the honeycomb structure 1 to a predetermined position, and heating the entire honeycomb
structure 1 to solder the inside of the cell 2. Connecting.
[0051]
The honeycomb type piezoelectric / electrostrictive element according to the present invention
can be used as a piezoelectric / electrostrictive speaker.
And, since the piezoelectric / electrostrictive speaker can reproduce the bass well, it can be
suitably used as a speaker replacing the conventional dynamic type speaker.
[0052]
FIG. 1 is a perspective view schematically showing an embodiment of a honeycomb-type
piezoelectric / electrostrictive element according to the present invention. It is the perspective
view which cut out and expanded the part A of FIG. 1A. FIG. 7 is a perspective view schematically
showing another embodiment of a honeycomb-type piezoelectric / electrostrictive element
according to the present invention.
Explanation of sign
[0053]
1: honeycomb structure portion 2: cell 2a: corner portion 3: partition wall 4: inner wall surface 5,
5a, 5b: inner electrode 6: outer peripheral wall 7, 7a, 7b: outer electrode 11: eye Sealed part, 12:
wiring, 100, 300: honeycomb type piezoelectric / electrostrictive element, A: part, a1, a2, a3, a4,
a5, a6, a7, a8: arrow.
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