JP2009295865A - Honeycomb type piezoelectric/electrostrictive element and piezoelectric/electrostrictive speaker using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric speaker successfully reproducing low-pitched sound. <P>SOLUTION: A honeycomb type piezoelectric/electrostrictive element 100 in which internal electrode 5b of internal electrodes 5a, 5b to be arranged as a pair on both sides of a partition is divided into a plurality of parts is used as the speaker. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a honeycomb-type piezoelectric / electrostrictive element and a piezoelectric / electrostrictive speaker using the same.

  In recent years, piezoelectric speakers have become widespread. This piezoelectric speaker is a speaker using a resonance phenomenon expressed by piezoelectric ceramics, and is characterized in that it is thinner and consumes less power than a conventional dynamic speaker.

  On the other hand, composite mobile devices are required to be thin with emphasis on design, to improve sound quality during music playback and TV viewing, and to extend battery life. For this reason, the use of piezoelectric speakers having the above-described features is progressing particularly for portable devices.

  However, conventional piezoelectric speakers composed of planar piezoelectric diaphragms are greatly inferior in volume and sound quality as compared with dynamic speakers. In particular, since it has the characteristics described above, it is difficult to reproduce the bass region faithfully to the original sound. Therefore, in order for the piezoelectric speaker to expand the market, it is necessary to match the sound quality with the requirements of the market.

  This invention is made | formed in view of such a situation, and makes it a subject to provide the piezoelectric speaker which can reproduce | regenerate low sound satisfactorily. As a result of repeated research, it has been found that this problem can be solved by the following means.

  That is, first, according to the present invention, a columnar honeycomb structure formed by partitioning and forming a plurality of cells in which a partition made of a piezoelectric / electrostrictive body penetrates in an axial direction is disposed so as to cover the surface of the partition. A honeycomb-type piezoelectric / electrostrictive element is provided in which at least one of the internal electrodes arranged in pairs with the partition wall is divided into a plurality of portions in the axial direction. Is done.

  In the honeycomb type piezoelectric / electrostrictive element according to the present invention, it is preferable that all of the plurality of cells are plugged at the same one end. In this case, adjacent cells among the plurality of cells are alternately plugged at the other end opposite to one end, and the internal electrodes divided into a plurality of portions in the axial direction are An internal electrode that is disposed on the surface of the partition wall forming a cell plugged at one end and plugged at the other end and that is divided into a plurality of portions in the axial direction is used as a power source. The wiring to be connected is preferably laid in a cell plugged at one end and plugged at the other end.

  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 are alternately opened (not plugged).

  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 with corners arcuate.

  In the honeycomb type piezoelectric / electrostrictive element according to the present invention, the honeycomb structure portion is obtained by firing a honeycomb formed body obtained by extruding a forming raw material mainly composed of a piezoelectric / electrostrictive material. preferable. Alternatively, in the honeycomb type piezoelectric / electrostrictive element according to the present invention, the honeycomb structure portion may be obtained by firing a honeycomb formed body obtained by laminating green sheets mainly composed of a piezoelectric / electrostrictive material. preferable.

  Next, according to the present invention, a piezoelectric element using any of the above-described honeycomb-type piezoelectric / electrostrictive elements that generate sound from an end of a cell using a partition as a diaphragm and a cell as a traveling wave forming space. / An electrostrictive speaker is provided.

  A piezoelectric / electrostrictive speaker according to the present invention includes a honeycomb-type piezoelectric / electrostrictive element in which at least one of internal electrodes arranged in a pair with a partition interposed therebetween 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 (pulsated) so that traveling waves are formed in the cells. It is possible to generate sound from an open cell. Accordingly, it is easier to generate a sound wave having a lower frequency than a piezoelectric speaker constituted by a conventional planar piezoelectric diaphragm. Moreover, since the sound wave has strong directivity in the longitudinal direction (axial direction) of the cell, it is suitable as a speaker having high directivity.

  In a preferred embodiment of the piezoelectric / electrostrictive speaker according to the present invention, a cell in which an internal electrode divided into a plurality of portions in the axial direction is plugged at one end and plugged at the other end. The wiring that is disposed on the surface of the partition wall that connects the internal electrode divided into a plurality of portions in the axial direction to the power source is plugged at one end and is connected at the other end. Since the honeycomb-type piezoelectric / electrostrictive element laid in the cell to be sealed is used, a cell for wiring and a cell for forming a traveling wave can be distinguished. Therefore, wiring becomes easy and noise is less likely to occur, improving sound quality.

  Hereinafter, embodiments of the present invention will be described with appropriate reference to the drawings, but the present 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 modes shown in the drawings or the information shown in the drawings. In practicing or verifying the present invention, the same means as described in this specification or equivalent means can be applied, but preferred means are those described below.

  1A and 1B are views schematically showing an embodiment of a honeycomb-type piezoelectric / electrostrictive element according to the present invention. 1A is a perspective view, and FIG. 1B is an enlarged perspective view of “part A” of FIG. 1A cut out. FIG. 2 is a cross-sectional view schematically showing another embodiment of the honeycomb-type piezoelectric / electrostrictive element according to the present invention, and shows a cross section parallel to the axial direction.

  A honeycomb piezoelectric / electrostrictive element 100 shown in FIGS. 1A and 1B includes a columnar honeycomb structure portion 1 having partition walls 3 that partition a plurality of cells 2 penetrating in an axial direction (central axial 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 wall 3 forming the cell 2, and the partition wall 3 is a piezoelectric / electrostrictive body. As shown in FIG. 2, in the honeycomb type piezoelectric / electrostrictive element 100, one of the internal electrodes 5 (internal electrodes 5 a and 5 b) disposed as a pair with the partition wall 3 interposed therebetween. The internal electrode 5b is divided into a plurality of portions in the axial direction P.

  A 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 of the cells 2 of the honeycomb type piezoelectric / electrostrictive element 100 are plugged by the plugging portion 11 at the same one end (the left end in FIG. 2). Adjacent cells of the cells 2 are alternately plugged by plugging portions 11 at the other end (the right end in FIG. 2) opposite to the one end. The internal electrode 5b divided into a plurality of portions is disposed on the surface (inner wall surface 4) of the partition wall 3 forming the cell 2 plugged at both ends, and is divided into a plurality of portions. The internal electrode 5a that is not present is disposed on the surface (inner wall surface 4) of the partition wall 3 that forms the cell 2 in which only one end (left side) is plugged.

  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 inside the cell 2 adjacent to the partition wall 3 therebetween. By applying a voltage between the electrodes 5 (5a, 5b), the partition walls 3 can be deformed, and thus the honeycomb structure 1 can be deformed. When a voltage is applied between the internal electrodes 5a and 5b disposed across the partition wall 3, the partition wall 3 extends in the thickness direction (d33 direction) and contracts in a direction perpendicular to the thickness direction (d31 direction). It can be deformed.

  As shown in FIG. 1B, the central axis direction P of the honeycomb-type piezoelectric / electrostrictive element 100 corresponds to a direction perpendicular to the thickness direction of the partition walls 3, and therefore the partition walls 3 are in directions indicated by arrows a1 and a2. Deforms to shrink. Also, the partition 3 is indicated by arrows a3 and a4 in the direction perpendicular to the thickness direction of the partition 3 on the plane (end surface and cross section) perpendicular to the central axis direction P of the honeycomb type piezoelectric / electrostrictive element 100. It deform | transforms so that it may shrink | contract in a direction and the direction shown by arrow a5 and a6. Further, in the thickness direction of the partition wall 3 in the plane (end surface and cross section) perpendicular to the central axis direction P of the honeycomb type piezoelectric / electrostrictive element 100, the partition wall 3 extends in the direction indicated by arrows a7 and a8. Deform. In this way, the partition wall 3 is deformed so as to extend in the thickness direction and contract in a direction perpendicular to the thickness direction.

  Therefore, for example, if a voltage is applied to the separated internal electrodes 5b at the same timing, the partition wall 3 is deformed in the same manner in any part, so that the honeycomb-type piezoelectric / electrostrictive element 100 generally has the cell 2 Shrinks in a direction through which the cell 2 penetrates (center axis direction P), and further shrinks in a plane perpendicular to the direction through which the cell 2 penetrates (center axis direction P). The partition wall 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 wall 3, the deformation in the thickness direction of the partition wall 3 narrows the space of the cell 2. Thus, the contribution to the change in the external shape of the honeycomb type piezoelectric / electrostrictive element 100 is small.

  On the other hand, if a voltage is applied to the divided internal electrodes 5b at different timings, the deformation timing of the partition walls 3 sandwiched between the internal electrodes 5b to which the voltages are applied at different timings is also shifted. Alternatively, if voltages having different waveforms are applied to the separated internal electrodes 5b, similarly, the partition walls 3 sandwiched between the internal electrodes 5b are deformed at different timings according to the voltage waveforms. Therefore, by applying such voltages, it is possible to pulsate the partition walls 3 instead of shrinking the honeycomb type piezoelectric / electrostrictive element 100 as a whole.

  These effects are also exhibited in the honeycomb type piezoelectric / electrostrictive element 300 constituted by the honeycomb type piezoelectric / electrostrictive element 100. Therefore, the honeycomb-type piezoelectric / electrostrictive elements 100 and 300 are used as piezoelectric / electrostrictive speakers that generate sound from the end of the cell 2 using the partition wall 3 as a diaphragm and the cell 2 as a traveling wave forming space. I can do it. In particular, the honeycomb-type piezoelectric / electrostrictive element 300 is suitable as a speaker having high directivity because only one end of the cell 2 is open.

  In the honeycomb structure 1 constituting the honeycomb type piezoelectric / electrostrictive elements 100 and 300, the outer peripheral wall 6 is disposed so as to surround the entire outermost periphery of the partition wall 3. The partition wall 3 is a piezoelectric / electrostrictive body, but the outer peripheral wall 6 may be a piezoelectric / electrostrictive body or other ceramic material.

The size of the honeycomb-type piezoelectric / electrostrictive elements 100 and 300 can be appropriately selected depending on the application. For example, when used as a piezoelectric / electrostrictive speaker, the cross-sectional area is preferably 0.3 to 1.5 mm ² and the length is about 30 to 80 mm.

  The thickness of the partition walls 3 of the honeycomb type piezoelectric / electrostrictive elements 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.

  The number of cells 2 formed in the honeycomb type piezoelectric / electrostrictive elements 100 and 300 can be appropriately selected depending on the application. For example, when used as a piezoelectric / electrostrictive speaker, 10 to 1000 are preferable, and 40 to 500 are more preferable.

  In the honeycomb type piezoelectric / electrostrictive elements 100 and 300, the shape of the cross section perpendicular to the central axis of the honeycomb structure portion 1 may be a quadrangle as shown in FIG. 1A, but other various shapes such as a pentagon, a hexagon, etc. It may be a square shape, or may be another shape such as a circle, an ellipse, 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. However, it may be other shapes such as a polygon such as a quadrangle whose corners are arc-shaped, a circle, an ellipse, or a track shape. "Rectangle with arc corners" refers to a quadrangle in which four corners (corresponding to vertices) are rounded in an arc shape in the cross-sectional shape perpendicular to the longitudinal direction of the cell 2 Say. Such a shape of the cell is preferable in that it can prevent electric field concentration in the portion corresponding to the corner portion of the internal electrode disposed in the cell.

  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 piezoelectric / electrostrictive material as a main component. Thereby, the honeycomb-type piezoelectric / electrostrictive elements 100 and 300 can be efficiently manufactured with few steps, and the manufacturing cost can be reduced. Alternatively, the honeycomb structure portion 1 may be formed by firing a laminate of green sheets mainly composed of a piezoelectric / electrostrictive material. Here, the phrase “having the piezoelectric / electrostrictive material as a 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 mass%.

  In the honeycomb type piezoelectric / electrostrictive elements 100 and 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 is increased, and a sufficient electric field is not applied to the piezoelectric / electrostrictive body. If the thickness is more than 5 μm, the inhibition of displacement cannot be ignored as an inactive portion.

  In the honeycomb type piezoelectric / electrostrictive element 300, the circuit for connecting the internal electrode 5 to the power source can be constituted by the plugging portion 11 for the internal electrode 5a that is not separated. That is, the plugged portion 11 is formed of a conductive material, and the plugged portions 11 are connected to each other on the side where all the cells 2 are plugged (the left side in FIG. 2). The electrode 5a may be connected (see FIG. 2) and a power source may be connected to the plugging portion 11. For the separated internal electrodes 5b, as shown in FIG. 2, the sealed wiring 12 is connected to each internal electrode 5b, and the wiring 12 is connected to the power source by passing through the plugging portion 11. Is possible. In this case, the wiring 12 that connects the internal electrode 5 b to the power source is laid in the cell 2 in which both ends are plugged with the plugging portions 11.

  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 that of the partition wall 3, and the plugging portion 11 is made insulative. An external electrode may be formed of a conductive material, and the internal electrode 5a may be connected thereto.

  In the honeycomb-type piezoelectric / electrostrictive element 300, the depth of the plugging portion 11 (the length that enters the cell 2) can be appropriately set depending on the application. For example, when used as a piezoelectric / electrostrictive speaker, 0.5 to 5 mm is preferable. Further, when used as a piezoelectric / electrostrictive speaker, the plugging portion 11 is preferably disposed so as to completely block the hole of the cell 2.

  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 eliminate elements that adversely affect the durability of the element, such as moisture in the outside world. On the other hand, in the case of a porous material, since there is air permeability between the inside and outside of the cell, there is an advantage that the reliability with respect to the pressure change in the outside world is high. When used as a piezoelectric / electrostrictive speaker, the plugging portion 11 is preferably dense.

  When the external electrode is provided, the thickness can be appropriately selected depending on the application. For example, when using as a piezoelectric / electrostrictive speaker, 0.1-20 micrometers is preferable.

  Next, the material of the honeycomb type piezoelectric / electrostrictive element according to the present invention will be described.

  The partition walls 3 of the honeycomb structure 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 strain, and may be crystalline or amorphous, and may be a semiconductor ceramic material or a strong material. A dielectric ceramic material or an antiferroelectric ceramic material may be used. What is necessary is just to select suitably according to a use and to employ | adopt. Moreover, even if it is a material which requires a polarization process, the material which is not required may be sufficient.

  Specifically, lead zirconate, lead titanate, lead magnesium niobate, lead nickel niobate, lead nickel tantalate, lead zinc niobate, lead manganese niobate, lead antimony stannate, lead manganese tungstate, cobalt niobium Lead oxide, lead magnesium tungstate, lead magnesium tantalate, barium titanate, sodium bismuth titanate, bismuth neodymium titanate (BNT), sodium niobate, potassium sodium niobate, strontium bismuth tantalate, barium copper tungsten, iron acid Examples thereof include bismuth or a composite oxide composed of two or more of these. 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 dissolved. Above all, materials containing nickel oxide with a composite oxide of lead zirconate, lead titanate, and lead magnesium niobate, and lead zirconate, lead titanate, lead magnesium niobate, lead nickel niobate A material containing a composite oxide as a main component is preferable because a large electric field induced strain can be used. Here, the main component refers to a component whose content exceeds 50% by mass. In this case, the nickel component is particularly preferably 0.05 to 3% by mass in terms of oxide. In addition, a material obtained by adding lithium bismutate, lead germanate, or the like to the above material is preferable because it can exhibit high material properties while realizing low-temperature firing of the piezoelectric / electrostrictive body. In particular, the above lead zirconate, titanium A material comprising nickel oxide as a main component of a composite oxide of lead oxide and lead magnesium niobate, containing 0.05 to 3% by mass in terms of oxide as the nickel component, and germanic acid A material containing 0.3 to 4% by weight of lead; a material mainly composed of a composite oxide of lead zirconate, lead titanate, lead magnesium niobate, and lead nickel niobate, and its nickel component A material containing 0.05 to 3% by mass in terms of oxide and 0.3 to 4% by mass of lead germanate is desirable.

  The internal electrode 5 is preferably made of a conductive metal material that is solid at room temperature. For example, simple metals or alloys containing aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, etc. Can be mentioned.

  When the external electrode is provided, the material is preferably made of a conductive metal that is solid at room temperature. For example, simple metals or alloys containing aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, etc. Can be mentioned.

  The material of the plugging portion is preferably a solid at room temperature and containing a conductive metal. For example, a simple metal or alloy containing aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, etc. I can list them.

  Next, a method for manufacturing a honeycomb-type piezoelectric / electrostrictive element according to the present invention will be described. The honeycomb type piezoelectric / electrostrictive element according to the present invention can be manufactured, for example, by the following method, but the method of manufacturing the honeycomb type piezoelectric / electrostrictive element according to the present invention is limited to the following method. It will never be done. Here, a method for manufacturing the honeycomb-type piezoelectric / electrostrictive element 300 will be described.

  First, a clay for forming the honeycomb structure portion 1 is formed. This is to use the raw materials mentioned above as the material of the partition walls 3 of the honeycomb structure 1 and mix and knead the raw materials to form a 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 form a forming raw material, which is kneaded to form a clay-like clay.

  As the organic binder, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol and the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type. As the dispersant, ethylene glycol, finished string, fatty acid soap, polyalcohol or the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type. When an organic solvent is used as the dispersion medium, it is preferable to use an organic solvent such as alcohol. As the organic solvent, for example, terpineol can be used. In this case, polyvinyl butyral can also be used as the organic binder. There is no restriction | limiting in particular as a method of kneading | mixing a shaping | molding raw material, For example, the method of using a kneader, a vacuum clay kneader, etc. can be mentioned.

  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 of producing a honeycomb molded object, Conventionally well-known shaping | molding methods, such as extrusion molding, injection molding, and press molding, can be used. Among them, a preferable example is a method of extruding the clay prepared as described above using a die having a desired cell shape, partition wall thickness, and cell density. Also, a slurry is prepared by mixing a raw material and an organic solvent containing a binder, and molded by a doctor blade method or the like to produce a green sheet having a plurality of through holes for forming cells. A honeycomb formed body may be manufactured by laminating the green sheets.

  Next, it is preferable to produce a honeycomb dried body by drying the obtained honeycomb formed body. The drying method is not particularly limited, and conventionally known drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying and the like can be used. Especially, the drying method which combined hot air drying and microwave drying or dielectric drying is preferable at the point which can dry the whole molded object rapidly and uniformly.

  Next, the obtained honeycomb dried body may be calcined before main firing to produce a calcined body. “Preliminary firing” means an operation of burning and removing organic substances (organic binder, dispersant, etc.) in the honeycomb formed body. The calcining temperature may be about 200 to 800 ° C. Although there is no restriction | limiting in particular as a calcination time, Usually, it is about 10 to 100 hours.

  Next, the honeycomb structure 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 ensure a predetermined strength. Since the firing conditions (temperature and time) vary depending on the type of molding raw material, appropriate conditions may be selected according to the type.

  Next, internal electrodes 5 (5a, 5b) are disposed on the inner wall surface 4 (surface of the partition walls 3) of the cells 2 of the honeycomb structure 1. The internal electrode 5a is disposed on the entire inner wall surface 4, and the internal electrode 5b is disposed on the inner wall surface 4 in a plurality of parts. For example, the internal electrode 5 can be disposed by the following method. First, the metal used as 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. The slurry concentration is preferably 50 to 80% by mass. Further, the viscosity of the slurry is preferably 0.05 to 50 Pa · s. And in the case of the internal electrode 5a, the honeycomb structure part 1 is immersed in a slurry, the slurry is made to adhere to the inner wall surface 4 of the cell 2, and then the whole inner wall surface 4 is covered by heating at 600-900 degreeC. Thus, the film-like internal electrode 5a can be disposed. In this case, when the slurry is attached to the inner wall surface 4 of the cell 2, it is preferable that the slurry is efficiently attached to the inner wall surface 4 of the cell 2 by sucking from the partition wall side. In the case of the internal electrode 5b, a material serving as a mask is attached to a portion where the electrode is not formed, and then the slurry is attached to the inner wall surface 4 of the cell 2 in the same manner as the internal electrode 5a. In addition to the above methods, plating, sputtering and the like are also used.

  Next, the plugging portion 11 is disposed on one end face of the honeycomb structure portion 1 in which the internal electrodes 5 (5a, 5b) are disposed. The method for disposing the plugging portion 11 is, for example, as follows. First, a plugging slurry (or plugging paste) containing a metal raw material powder used in the plugging portion 11, an organic solvent such as water or alcohol, and an organic binder is stored in a storage container. . The slurry concentration is preferably 50 to 90% by mass. The viscosity of the slurry is preferably 5 to 5000 Pa · s. Then, one end portion of the honeycomb structure portion 1 provided with the internal electrode 5 is immersed in a storage container, and the plugging slurry is filled in the opening portion of the cell 2 to form the plugging portion 11. To do. When there is a cell 2 without the plugged portion 11, a mask may be applied to the cell 2 without the plugged portion 11 among the cells at the respective end portions.

  The wiring 12 is formed by inserting a coated conductor wire with solder at the tip from the end face of the honeycomb structure 1 to a predetermined position, further heating the entire honeycomb structure 1 and soldering inside the cell 2. Connecting.

  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 low sound satisfactorily, it can be suitably used as a speaker replacing the conventional dynamic speaker.

1 is a perspective view schematically showing one 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. 6 is a perspective view schematically showing another embodiment of a honeycomb type piezoelectric / electrostrictive element according to the present invention.

Explanation of symbols

1: honeycomb structure, 2: cell, 2a: corner, 3: partition, 4: inner wall surface, 5, 5a, 5b: internal electrode, 6: outer peripheral wall, 7, 7a, 7b: external electrode, 11: eye Sealing part, 12: wiring, 100, 300: honeycomb type piezoelectric / electrostrictive element, A: part, a1, a2, a3, a4, a5, a6, a7, a8: arrows.

Claims (7)

A columnar honeycomb structure formed by partitioning a plurality of cells in which a partition made of a piezoelectric / electrostrictive body penetrates in the axial direction; and an internal electrode disposed so as to cover the surface of the partition;
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.   The honeycomb-type piezoelectric / electrostrictive element according to claim 1, wherein all of the plurality of cells are plugged at the same one end. Adjacent cells of the plurality of cells are alternately plugged at the other end opposite to the one end,
An internal electrode divided into a plurality of portions in the axial direction is disposed on the surface of the partition wall forming the cell plugged at the one end and plugged at the other end. ,
A wiring for connecting an internal electrode divided into a plurality of parts in the axial direction to a power source is laid in a cell plugged at one end and plugged at the other end. 2. A honeycomb-type piezoelectric / electrostrictive element according to 2.   The honeycomb-type piezoelectric / electrostrictive element according to any one of claims 1 to 3, wherein a cross-sectional shape perpendicular to the longitudinal direction of the cell is a quadrangle with corners arced.   The honeycomb type according to any one of claims 1 to 4, wherein the honeycomb structure part is obtained by firing a honeycomb formed body obtained by extruding a forming raw material mainly composed of a piezoelectric / electrostrictive material. Piezoelectric / electrostrictive element.   The honeycomb type piezoelectric / according to any one of claims 1 to 4, wherein the honeycomb structure is obtained by firing a honeycomb formed body obtained by laminating green sheets mainly composed of a piezoelectric / electrostrictive material. Electrostrictive element.   The honeycomb type piezoelectric / electrostrictive element according to any one of claims 1 to 6, wherein the partition wall is used as a diaphragm, the cell is used as a traveling wave forming space, and sound is generated from an end of the cell. Piezoelectric / electrostrictive speaker.

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