JP2005026583A - Ceramic laminated electromechanical sensing element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic laminated electromechanical sensing element which is industrially easily manufactured and can prevent the occurrence of cracks in applying an electric field. <P>SOLUTION: A laminated body 4 is composed of a plurality of ceramic layers 2, a plurality of internal electrode layers 3 laminated alternately and a pair of external electrodes 9. Each of the pair of external electrodes 9 is alternately electrically connected to the plurality of internal electrode layers 3. The laminated body 4 has a displacement generating region where mechanical displacement is generated in a laminated direction by the application of the electric field, and a pair of displacement non-generating regions 61, 63 and 62, 64 where the mechanical displacement is not generated. Each of the pair of displacement non-generating regions 61, 63 and 62, 64 has two displacement non-generating parts 61, 63 and 62, 64, respectively. The two displacement non-generating parts 61, 63 and 62, 64 are in a discontinuous state of being disposed at each boundary so that a section at the boundary end of the one displacement non-generating parts 61, 62 is fully off from an extension line in the laminated direction of the boundary end of the other displacement non-generating parts 63, 64. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ceramic laminated electromechanical transducer.
[0002]
[Prior art]
A ceramic laminated electromechanical transducer generally includes a laminate in which a plurality of ceramic layers and a plurality of internal electrode layers are alternately stacked and integrally sintered, and a pair of external electrodes, and each internal The electrode layer has a partial electrode as an internal electrode. The external electrodes are respectively disposed on the two side surfaces of the laminate, and are electrically connected to the partial electrodes every other layer.
[0003]
Each partial electrode has an electrode area smaller than the cross-sectional area of the element (stacked body), and its edge surface is exposed at least one of the side surfaces of the stacked body on which the two external electrodes are arranged. Each partial electrode is electrically connected to the external electrode disposed on the side surface of the laminate at which the edge surface of the partial electrode is exposed, but is externally disposed on the side surface of the laminate at which the edge surface is not exposed. It is not electrically connected to the electrode.
[0004]
The ceramic layer is mainly composed of piezoelectric or electrostrictive ceramics, and is mechanically displaced when a voltage is applied between the external electrodes. Due to the presence of a region where no partial electrode of each internal electrode layer is provided (hereinafter referred to as an electrodeless portion), a ceramic layer between a pair of adjacent internal electrode layers is sandwiched between the partial electrodes of the two internal electrode layers. There is a part that is not sandwiched and a part that is not sandwiched. When a voltage is applied between the external electrodes, the portion sandwiched between the partial electrodes of the two portions is displaced, but the portion not sandwiched between the partial electrodes is not displaced, and stress is generated near the boundary between the two electrodes. . If the maximum stress generated exceeds the fracture strength of the ceramic layer, there is a risk that a crack will occur and damage will occur. In addition, cracks cause the moisture resistance to deteriorate significantly. For this reason, when an electric field is applied to the device in a high-humidity atmosphere, the metal forming the internal electrode migrates through the crack, and the partial electrode and the external electrode are electrically connected at the site where insulation is required. There is a risk of conduction.
[0005]
As a structure for the purpose of avoiding such inconvenience, grooves having a width of 0.1 mm and a depth of 0.1 mm are formed at intervals of 2 mm on the entire periphery of the element on a side surface parallel to the stacking direction of the element. (For example, refer to Patent Document 1).
[0006]
[Patent Document 1]
Japanese Patent Publication No. 6-5794
[0007]
[Problems to be solved by the invention]
However, in the structure of Patent Document 1, the number of grooves formed with respect to the length of the element (laminated body) is large. For example, in the case where the length of the element is 30 mm, 14 grooves must be formed, which is a burden on manufacturing, and increases man-hours and costs. In addition, forming the groove around the entire periphery of the element also becomes a manufacturing burden, and increases man-hours and costs.
[0008]
Accordingly, an object of the present invention is to provide a ceramic laminated electromechanical transducer that can be easily produced industrially and that can prevent the occurrence of cracks when an electric field is applied, and a method for manufacturing the same.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a ceramic laminated electromechanical transducer according to the present invention includes a plurality of ceramic layers made of a material that is displaced by application of an electric field, and a plurality of internal electrode layers laminated alternately with the ceramic layers. It is comprised with the laminated body which consists of a pair of external electrode. Each of the pair of external electrodes is electrically connected to a plurality of internal electrode layers alternately. The laminate includes at least four displacement-free portions that do not cause mechanical displacement in the lamination direction even when an electric field is applied.
[0010]
In the above configuration, there are provided at least four displacement-free portions that do not cause mechanical displacement in the stacking direction when a voltage is applied to the external electrode. On the other hand, in the conventional structure, the displacement non-occurrence portions are provided only in two places. That is, in the above-described configuration, the displacement-free portions conventionally provided at two locations are each divided into two or more portions. Therefore, when the total length in the stacking direction of the elements is the same, the configuration of the present invention can suppress the length of each displacement-free portion as compared with the conventional structure. In each ceramic layer, the magnitude of the generated stress increases as the length of the non-displaced portion in the stacking direction becomes longer. Therefore, according to the above configuration, the generated stress can be suppressed to a smaller value. Crack generation and growth can be prevented.
[0011]
In addition, since the above configuration is obtained by changing the arrangement pattern of the portion where no displacement occurs, the manufacturing burden is reduced as compared with the case where a large number of grooves are formed in the laminate, and industrial production Can be easily performed.
[0012]
Moreover, a ceramic laminated electromechanical transducer of another aspect according to the present invention includes a plurality of ceramic layers made of a material that is displaced by application of an electric field, and a plurality of internal electrode layers laminated alternately with the ceramic layers, It is comprised with the laminated body which consists of a pair of external electrode. Each of the pair of external electrodes is electrically connected to a plurality of internal electrode layers alternately. The multilayer body has a displacement generation region that generates a mechanical displacement in the stacking direction in accordance with application of an electric field, and a pair of non-displacement regions that do not generate a mechanical displacement corresponding to the formation site of the pair of external electrodes. . Each of the pair of displacement non-occurrence regions has at least two displacement non-occurrence portions. The two non-displacement portions are discontinuous at each boundary. In the present invention, the discontinuous state is a state in which the cross section of the boundary end of one displacement non-occurrence portion is disposed completely away from the extension in the stacking direction of the cross section of the boundary end of the other displacement non-occurrence portion, or a portion This means a state where they are arranged in an overlapping manner.
[0013]
In the above configuration, when a voltage is applied to the external electrode, the displacement generation region of the laminate is displaced, and the displacement non-occurrence region (displacement non-occurrence portion) is not displaced. A stress is generated between the generation region (the portion where no displacement occurs). The magnitude of the generated stress increases as the length in the stacking direction of the portion where no displacement occurs increases.
[0014]
In this regard, in the present invention, each displacement non-occurrence region has at least two displacement non-occurrence portions, and the two displacement non-occurrence portions are discontinuous at the boundary between the two. Therefore, even if the total length in the stacking direction of the stack is formed long, the length of the non-displaceable portion in the stacking direction can be kept short, so that the generated stress can be kept small, and crack generation and growth can be prevented. Can do.
[0015]
In addition, since the above configuration is obtained by changing the arrangement pattern of the portion where no displacement occurs, the manufacturing burden is reduced as compared with the case where a large number of grooves are formed in the laminate, and industrial production Can be easily performed.
[0016]
The ceramic laminated electromechanical transducer having the above-described configuration can be obtained, for example, by the following first aspect.
[0017]
In the first aspect, the ceramic layer is mainly composed of so-called piezoelectric ceramics or electrostrictive ceramics, and is integrally sintered together with the internal electrode layer to form a laminate.
Each internal electrode layer is composed of partial electrodes and non-electrode portions, and the partial electrodes are electrically connected alternately to the pair of external electrodes every other layer. The internal electrode layers are alternately stacked with the ceramic layer interposed therebetween, and a first internal electrode layer electrically connected to one external electrode and a second internal electrode layer electrically connected to the other external electrode are provided. Have. The stacked body has at least two regions (a first region and a second region) having a predetermined position in the stacking direction as a boundary. In the first region, the electrodeless portion of the first internal electrode layer is disposed on the first stacking axis, and the electrodeless portion of the second internal electrode layer is disposed on the second stacking axis. In the second region, the electrodeless portion of the first internal electrode layer is disposed on the third stacking axis, and the electrodeless portion of the second internal electrode layer is disposed on the fourth stacking axis. The first stacking axis, the second stacking axis, the third stacking axis, and the fourth stacking axis are substantially parallel to the stacking direction of the stacked body and do not overlap each other. In the first region, a displacement non-occurrence region (displacement non-occurrence portion) occurs along the first stacking axis and the second stacking axis, and in the second region, along the third stacking axis and the fourth stacking axis. A displacement non-occurrence region (displacement non-occurrence portion) occurs. That is, the non-displacement portion is discontinuous between the first region and the second region. Therefore, even if the total length in the stacking direction of the stack is increased, the generated stress can be suppressed by reducing the length in the stacking direction of the non-displaceable region (displacement-free portion), and cracks can be generated. And growth can be prevented.
[0018]
In the above aspect, the external electrode may be composed of the following first to fourth external electrodes. The first external electrode is one of the pair of external electrodes in the first region, and is disposed on the side surface of the stacked body where the non-electrode portion of the first internal electrode layer is exposed, and is electrically connected to the partial electrode of the second internal electrode layer. Connected to. The second external electrode is the other of the pair of external electrodes in the first region, and is disposed on the side surface of the stacked body where the non-electrode portion of the second internal electrode layer is exposed, and is electrically connected to the partial electrode of the first internal electrode layer. Connected to. The third external electrode is one of the pair of external electrodes in the second region, and is disposed on the side surface of the stacked body where the non-electrode portion of the first internal electrode layer is exposed, and is electrically connected to the partial electrode of the second internal electrode layer. Connected to. The fourth external electrode is the other of the pair of external electrodes in the second region, and is disposed on the side surface of the stacked body where the non-electrode portion of the second internal electrode layer is exposed, and is electrically connected to the partial electrode of the first internal electrode layer. Connected to.
[0019]
Further, the minimum length in the stacking direction (hereinafter referred to as the minimum fracture length) in which a crack is generated in each displacement-free portion when a predetermined electric field is applied to the ceramic layer is obtained in advance experimentally or by calculation. The length in the stacking direction of each displacement-free portion is preferably set to be smaller than this minimum fracture length. This minimum breakdown length is determined by various conditions such as the strength of the applied electric field, the material and size of the ceramic layer, and the size and shape of the partial electrode. Thus, by setting the length in the stacking direction of each displacement-free portion to be smaller than the minimum fracture length, the generation and growth of cracks can be reliably prevented.
[0020]
The element can be obtained by forming a laminate composed of a ceramic green sheet for forming a ceramic layer and a metal paste for forming an internal electrode layer, and then firing this integrally.
[0021]
The element can also be obtained by previously integrally firing each laminated body region having a plurality of non-displacement portions and then bonding these regions with an adhesive.
[0022]
In addition, between the stacked regions adjacent to each other in the stacking direction at the boundary, electrical connection between adjacent regions can be achieved by electrically connecting one external electrode in each stacked region to the internal electrode layer in the other stacked region. Connections can also be made.
[0023]
For example, in the first aspect, the configuration is such that the second external electrode extends to the first internal electrode layer at the boundary end of the second region, and is electrically connected to the partial electrode of the first internal electrode layer, The third external electrode can be obtained by extending to the second internal electrode layer at the boundary end of the first region and electrically connecting to the partial electrode of the second internal electrode layer.
[0024]
With such a configuration, electrical connection between adjacent regions can be electrically connected via the internal electrode layer without requiring a separate connection line, and the structure can be simplified.
[0025]
In addition, it is also possible to configure such that the non-displacement portion of one region of the adjacent stacked body region extends in the stacking direction beyond the boundary and reaches a predetermined position in the other region.
[0026]
In such a configuration, for example, in the first aspect, in the first region of the stacked body, the second internal electrode layer is disposed at the boundary end, and in the second region, the first internal electrode layer is disposed at the boundary end. An endless second internal electrode layer is provided with an electrodeless portion disposed on the fourth stacking axis, and is disposed on the third stacking axis in the first internal electrode layer of the first region adjacent to the second internal electrode at the boundary end The second internal electrode in the second region adjacent to the first internal electrode at the boundary end is provided with the electrodeless portion disposed on the first stacking axis in the first internal electrode layer at the boundary end. It can be obtained by providing an electrodeless portion disposed on the second lamination axis in the layer.
[0027]
In the above configuration, even when the external electrode extends from one region beyond the boundary to a predetermined position in the other region, the insulation state between the external electrode and the internal electrode layer in the other region is maintained. be able to.
[0028]
Specifically, in the above aspect, the first external electrode further extends along the first stacking axis from the partial electrode of the second internal electrode layer at the boundary end of the first region, and the first internal electrode at the adjacent boundary end Even when reaching the layer, the first internal electrode layer is provided with an electrodeless portion disposed on the first stacking axis in addition to the electrodeless portion disposed on the third stacking axis. Therefore, the first external electrode and the partial electrode of the first internal electrode layer are kept in an insulated state. Similarly, the second external electrode further extends from the partial electrode of the first internal electrode layer at the boundary end of the second region along the second stacking axis, and the second external electrode of the second region adjacent to the first internal electrode layer at the boundary end Even when the second internal electrode layer is reached, the second internal electrode layer includes an electrodeless portion disposed on the second stacking axis in addition to the electrodeless portion disposed on the fourth stacking axis. Since the portion is provided, the second external electrode and the partial electrode of the second internal electrode layer are kept in an insulated state. The third external electrode further extends along the third stacking axis from the partial electrode of the second internal electrode layer at the boundary end of the first region, and the first internal portion of the first region adjacent to the second internal electrode layer at the boundary end Even when it reaches the electrode layer, the first internal electrode layer is provided with an electrodeless portion arranged on the third lamination axis in addition to the electrodeless portion arranged on the first lamination axis. Therefore, the third external electrode and the partial electrode of the first internal electrode layer are kept in an insulated state. Even when the fourth external electrode further extends along the fourth stacking axis from the partial electrode of the first internal electrode layer at the boundary end of the second region and reaches the second internal electrode layer at the adjacent boundary end. The second internal electrode layer is provided with an electrodeless portion arranged on the fourth lamination axis in addition to an electrodeless portion arranged on the second lamination axis. The partial electrode of the second internal electrode layer is kept in an insulated state.
[0029]
Therefore, the operation of forming the external electrode on the side surface of the laminate can be easily performed, and the productivity is improved.
[0030]
Further, the laminated body may be formed in a substantially prismatic shape, and a non-displacement portion and an external electrode may be formed at the corner portion.
[0031]
Moreover, it is good also considering the laminated body cross-sectional shape of a displacement non-occurrence | production part as the triangular shape which makes the side surface of a laminated body two sides, and the substantially sector shape which makes the side surface of a laminated body two sides.
[0032]
Further, the corner portions may be chamfered, and external electrodes may be formed on the chamfered portions.
[0033]
Further, a groove for relaxing stress may be formed on a side surface intersecting with the stacking direction of the stacked body.
[0034]
In the above configuration, due to the presence of the groove, the generated stress is further reduced, and the occurrence of cracks can be more reliably prevented.
[0035]
The tip of the groove may be curved.
[0036]
For example, when the tip of the groove has a corner, a crack may be generated and grow by using the corner as a trigger. On the other hand, if the tip of the groove is curved, there is no corner that triggers the generation of cracks, so that the generation of cracks can be prevented more reliably.
[0037]
You may form the thickness of the ceramic layer in which the groove | channel was formed larger than the thickness of another ceramic layer.
[0038]
In the above configuration, the thickness of the ceramic layer that does not have a groove can be set small to increase the amount of displacement of the element while keeping the applied voltage small, and the thickness of the ceramic layer that forms the groove The groove can be easily worked by setting the length large, and industrial production becomes easier.
Further, each of the non-displacement portions may be composed of two ceramic layers that are continuous in the stacking direction.
[0039]
In the above configuration, each displacement-free portion is composed of the minimum unit, that is, two ceramic layers continuous in the stacking direction, so that the length of the displacement-free portion in the stacking direction can be minimized. Therefore, the stress generated in the stacking direction is reduced, and crack generation and growth can be reliably prevented.
[0040]
Further, each of the pair of external electrodes may be continuously formed with an inclination with respect to the stacking direction.
[0041]
According to the above configuration, the external electrode can be easily formed.
[0042]
The ceramic laminated electromechanical transducer having the above-described configuration can be obtained by, for example, the following second aspect.
[0043]
In the second aspect, the ceramic layer is mainly composed of so-called piezoelectric ceramics or electrostrictive ceramics, and is integrally sintered together with the internal electrode layer to form a laminate. Each internal electrode layer is composed of partial electrodes and non-electrode portions, and the partial electrodes are electrically connected alternately to the pair of external electrodes every other layer. The internal electrode layer includes a first internal electrode layer electrically connected to one external electrode and a second internal electrode layer electrically connected to the other external electrode, which are alternately stacked with a ceramic layer interposed therebetween. Have. The electrodeless portion of the first internal electrode layer is disposed on the first stacking axis that is inclined with respect to the stacking direction, and the electrodeless portion of the second internal electrode layer is on the second stacking axis that is tilted with respect to the stacking direction. Is arranged.
[0044]
Even in such a second aspect, it is clear that the same specifications as those of the first aspect can be obtained with respect to the manufacturing method of the laminate, the shape thereof, the shape of the partial electrodes, and the like.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
1st Embodiment of this invention is described based on drawing.
[0046]
FIG. 1 is a perspective view showing a first embodiment of a ceramic laminated electromechanical transducer according to the present invention, and FIG. 2 is a perspective view seen through a ceramic layer of the laminated body of FIG.
[0047]
As shown in FIGS. 1 and 2, the ceramic multilayer electromechanical transducer 1 includes a plurality of ceramic layers 2 that are displaced by application of an electric field, a plurality of internal electrode layers 3, and a plurality of external electrodes 9. ing. The ceramic layers 2 and the internal electrode layers 3 are alternately stacked and integrated by sintering to form a laminate 4.
[0048]
The internal electrode layers 3 are respectively connected to two pairs of external electrodes 9 every other layer, and a predetermined electric field is applied to each ceramic layer 2 by voltage application from the external electrodes 9. Both the ceramic layer 2 and the internal electrode layer 3 have a rectangular plate shape, and the laminate 4 has a prismatic shape. Each ceramic layer 2 has substantially the same thickness. In addition, the shape of the laminated body 4 is not limited to prismatic shape, For example, it can set to various shapes, such as a column shape and a hollow cylinder shape.
[0049]
The internal electrode layer 3 is divided into a first internal electrode layer 5 and a second internal electrode layer 6. The ceramic layer 2 and the internal electrode layer 3 are laminated in the order of the ceramic layer 2, the first internal electrode layer 5, the ceramic layer 2, the second internal electrode layer 6, the ceramic layer 2.
That is, the first internal electrode layers 5 and the second internal electrode layers 6 are alternately stacked with the ceramic layer 2 interposed therebetween.
[0050]
Each internal electrode layer 3 (5, 6) has a partial electrode 7 and a non-electrode portion 8. In the non-electrode portion 8, adjacent ceramic layers 2 with the internal electrode layer 3 interposed therebetween are integrated.
Each partial electrode 7 has a shape in which one corner is cut out of a rectangular plate shape, and the cut-out corner constitutes an electrodeless portion 8.
[0051]
The stacked body 4 has at least two regions (four regions in this embodiment) having a predetermined position in the stacking direction as a boundary. In the present embodiment, the laminate 4 has four regions (first region 21, second region 22, and second region 22, which are sequentially layered) having boundaries 25, 26, and 27 that divide the length in the layer direction into approximately three equal parts. It has a third area 23 and a fourth area 24). Hereinafter, the configuration of the first region 21 and the second region 22 will be described. Since the third region 23 has the same basic configuration as the first region 21 and the fourth region 24 has the same basic configuration as the second region 22, the description thereof will be omitted.
[0052]
As shown in FIG. 2, in the first region 21, the non-electrode portion 8 of the first internal electrode layer 5 and the non-electrode portion 8 of the second internal electrode layer 6 have four side portions 4 a, 4b, 4c, and 4d are arranged on a pair of two side portions 4a and 4b that face each other.
In other words, the electrodeless portion 8 of the first internal electrode layer 5 and the electrodeless portion 8 of the second internal electrode layer 6 are substantially parallel to the stacking direction and do not overlap each other with two stacking axes (first in the vicinity of the side portion 4a). Arranged on the lamination axis 31 and the second lamination axis 32 in the vicinity of the side portion 4b.
[0053]
In the first region 21, the first external electrode 36, which is one of the pair of external electrodes 9, is along the side part 4 a of the stacked body 4 where the electrodeless part 8 of the first internal electrode layer 5 is exposed. Arranged and fixed. Thereby, the first external electrode 36 is electrically connected to the partial electrode 7 of the second internal electrode layer 6 and is maintained in an insulated state from the partial electrode 7 of the first internal electrode layer 5. The second external electrode 37, which is the other of the pair of external electrodes 9, is disposed and fixed along the side portion 4 b of the stacked body 4 where the electrodeless portion 8 of the second internal electrode layer 6 is exposed. . As a result, the second external electrode 37 is electrically connected to the partial electrode 7 of the first internal electrode layer 5 and is maintained in an insulated state from the partial electrode 7 of the second internal electrode layer 6.
[0054]
In the second region 22, the non-electrode portion 8 of the first internal electrode layer 5 and the non-electrode portion 8 of the second internal electrode layer 6 are among the four side portions 4 a, 4 b, 4 c, 4 d of the stacked body 4. In the first region 21, the electrodeless portions 8 are disposed on the two opposing side portions 4 c and 4 d that are not disposed. That is, the electrodeless portion 8 of the first internal electrode layer 5 and the electrodeless portion 8 of the second internal electrode layer 6 are substantially parallel to the stacking direction and do not overlap with each other. They are arranged on two different lamination axes (a third lamination axis 33 in the vicinity of the side part 4c and a fourth lamination axis 34 in the vicinity of the side part 4d).
[0055]
In the second region 22, the third external electrode 38, which is one of the pair of external electrodes 9, extends along the side part 4 c of the stacked body 4 where the electrodeless part 8 of the first internal electrode layer 5 is exposed. Arranged and fixed. Thereby, the third external electrode 38 is electrically connected to the partial electrode 7 of the second internal electrode layer 6 and is maintained in an insulated state from the partial electrode 7 of the first internal electrode layer 5. The fourth external electrode 39, which is the other of the pair of two external electrodes 9, is disposed and fixed along the side portion 4 d of the stacked body 4 where the electrodeless portion 8 of the second internal electrode layer 6 is exposed. . As a result, the fourth external electrode 39 is electrically connected to the partial electrode 7 of the first internal electrode layer 5 and is kept in an insulated state from the partial electrode 7 of the second internal electrode layer 6.
[0056]
Thus, one of the pair of external electrodes 9 is constituted by the first external electrode 36 and the third external electrode 38 that are electrically connected to the partial electrode 7 of the second internal electrode layer 6, and the other is The second external electrode 37 and the fourth external electrode 39 are electrically connected to the partial electrode 7 of the first internal electrode layer 5.
[0057]
At the boundary 25 between the first region 21 and the second region 22, the second internal electrode layer 6 (42) is disposed at the boundary end on the first region 21 side, and at the boundary end on the second region 22 side, the first internal Electrode layer 5 (41) is arranged.
[0058]
The first external electrode 36 in the first region 21 is disposed in the first region 21 so as not to contact the partial electrode 7 of the first internal electrode layer 41 at the boundary end on the second region 22 side.
On the other hand, the second external electrode 37 in the first region 21 extends beyond the boundary 25 to the first internal electrode layer 41 at the boundary end of the second region 22, and the partial electrode 7 of the first internal electrode layer 41. Is electrically connected.
[0059]
The fourth external electrode 39 in the second region 22 is disposed in the second region 21 so as not to contact the partial electrode 7 of the second internal electrode layer 42 at the boundary end on the first region 21 side.
On the other hand, the third external electrode 38 in the second region 22 extends beyond the boundary 25 to the second internal electrode layer 42 at the boundary end of the first region 21, and the partial electrode 7 of the second internal electrode layer 42. Is electrically connected.
[0060]
Thus, the first external electrode 36 and the third external electrode 38 are electrically connected via the partial electrode 7 of the second internal electrode layer 42 at the boundary end of the first region 21. The second external electrode 37 and the fourth external electrode 39 are electrically connected via the partial electrode 7 of the first internal electrode layer 41 at the boundary end of the second region 22. Accordingly, the external electrode in the first region and the external electrode in the second region can be electrically connected via the partial electrode 7 without requiring a separate connection line, thereby simplifying the structure. Can do.
[0061]
The ceramic layer 2 is made of so-called piezoelectric ceramics or electrostrictive ceramics. Piezoelectric ceramics and electrostrictive ceramics both have the property of being distorted (displaced) when an electric field (voltage) is applied. As a typical material of piezoelectric ceramics, Pb (Zr, Ti) O ₃ And BaTiO ₃ and so on. As a typical material of electrostrictive ceramics, Pb (Mg _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ And Pb (Ni _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ And (Pb, La) (Zr, Ti) O ₃ and so on. In the case of piezoelectric ceramics, it is necessary to perform a so-called polarization process for aligning the direction of polarization in one direction. Pb (Zr, Ti) O ₃ Are PZT and BaTiO ₃ Is BT and Pb (Mg _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ Are PMN-PT and Pb (Ni _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ Are PNN-PT and (Pb, La) (Zr, Ti) O. ₃ Are abbreviated as PLZT.
[0062]
In each ceramic layer 2, the portion sandwiched between adjacent pairs of partial electrodes 7 is displaced (stretched) in the stacking direction by application of an electric field, but the portion not sandwiched between partial electrodes 7 is not displaced, and the boundary between the two Stress is generated in the vicinity.
[0063]
The magnitude of the stress in the stacking direction generated in the stacked body 4 due to the application of the electric field increases from both ends in the stacking direction of the stacked body 4 toward the center, and becomes the maximum stress at a predetermined position.
This maximum stress is a region in which partial electrodes 7 and non-electrode portions 8 are alternately and continuously stacked on the same stack axis 31, 32, 33, 34 substantially parallel to the stacking direction with the ceramic layer 2 interposed therebetween ( Hereinafter, it increases as the length in the stacking direction of the non-displacement region increases.
[0064]
In the laminate 4, a pair of displacement non-occurrence regions that do not cause mechanical displacement in the stacking direction are generated with the application of an electric field. One is a non-displacement region (hereinafter referred to as a first displacement non-occurrence region) due to the non-electrode portion 8 of the first internal electrode layer 5, and the other is the non-electrode portion 8 of the second internal electrode layer 6. Is a displacement non-occurrence region (hereinafter referred to as a second displacement non-occurrence region). In other words, the first displacement-free region corresponding to the first external electrode 36 and the third external electrode 38 that are one of the pair of external electrodes 9, and the second external electrode 37 and the fourth external electrode 39 that are the other one. And a second displacement non-occurrence region corresponding to. In addition, a portion of the laminate 4 excluding these portions where no displacement occurs becomes a displacement generation region in which mechanical displacement occurs in the stacking direction with the application of an electric field.
[0065]
In the present embodiment, the stacked body 4 has four regions 21, 22, 23, and 24 having boundaries 25, 26, and 27 as predetermined positions in the stacking direction. In the first region 21 and the third region 23, the electrodeless portion 8 of the first internal electrode layer 5 is disposed on the first stacked shaft 31, and the electrodeless portion 8 of the second internal electrode layer 6 is connected to the second stacked shaft 32. Is placed on top. In the second region 21 and the fourth region 24, the electrodeless portion 8 of the first internal electrode layer 5 is disposed on the third stacked shaft 33, and the electrodeless portion 8 of the second internal electrode layer 6 is connected to the fourth stacked shaft 34. Is placed on top.
[0066]
In the first region 21 and the third region 23, a first displacement non-occurrence region 61 (shown in FIG. 2) is generated along the first laminated axis 31 corresponding to the first external electrode 36, and the second external electrode 37 A second displacement non-occurrence region 62 (shown in FIG. 2) is generated along the corresponding second stacking axis 32. In the second region 22 and the fourth region 24, a first displacement non-occurrence region 63 (shown in FIG. 2) is generated along the third laminated axis 33 corresponding to the third external electrode 38, and the fourth external electrode 39 A second non-displacement region 64 (shown in FIG. 2) is generated along the corresponding fourth stacking axis 34. That is, in each of the regions 21, 22, 23, and 24, two displacement non-occurrence portions 61, 62, 63, and 64 are generated, and the second region 22 is formed between the first region 21 and the second region 22. The first displacement non-occurrence regions (displacement non-occurrence portions) 61 and 63 and the second displacement non-occurrence regions (displacement) between the region 22 and the third region 23 and between the third region 23 and the fourth region 24, respectively. (Non-occurrence part) 62 and 64 become discontinuous. Here, “discontinuity” means that two displacement non-occurrence portions are each at the boundary, and the cross section of the boundary end of one displacement non-occurrence portion is an extension of the cross section of the boundary end of the other displacement non-occurrence portion in the stacking direction. It is a state where it is completely deviated from the state, or a state where it is partially overlapped.
[0067]
Therefore, even if the total length in the stacking direction of the stacked body 4 is formed long, the stress generated by suppressing the length in the stacking direction of the non-displacement region can be suppressed to a small level, and crack generation and growth can be prevented. be able to.
[0068]
Further, in the same displacement-free region, the shape and arrangement direction of the ceramic layers 2 are uniform in the lamination direction, the electrodeless portions 8 are alternately arranged along the lamination direction, and the ceramic layers 2 have substantially the same thickness. The maximum stress in the non-displacement region is generated at a substantially central portion in the stacking direction of the non-displacement region, and the maximum stress is the length of the non-displacement region in the stacking direction. Increase / decrease according to increase / decrease. When an electric field is applied, if the length in the stacking direction of the displacement-free region is equal to or greater than a predetermined value (minimum fracture length) Lm, a crack is generated in the ceramic layer 2 at the maximum stress generation portion. This minimum breakdown length Lm is uniquely determined by various conditions such as the strength of the electric field applied (the magnitude of the voltage between the external electrodes 9), the material and dimensions of the ceramic layer 2, and the dimensions of the partial electrode 7. Is done.
[0069]
In the present embodiment, the length of the displacement-free region in the stacking direction (the length of each region in the stacking direction) is set to be smaller than the minimum fracture length Lm.
[0070]
For example, it is composed of a single region (for example, only the first region 21 in FIG. 1), the displacement-free region has a length in the stacking direction of 30 mm, and a cross section perpendicular to the stacking direction is approximately square of 7 mm × 7 mm, For a laminate (element) in which the length (height) of one layer including the ceramic layer and the internal electrode layer is 80 μm and the number of laminated layers is 375 layers, the applied voltage is gradually increased. When an electric field of 960 V / mm is applied, a small crack is generated along the internal electrode layer from the end of the partial electrode toward the non-electrode portion on the side surface of the stacked body in the vicinity of the approximate center in the stacking direction. Such a result can be obtained by performing a destructive experiment or performing a calculation using a finite element method or the like. That is, in the above laminate, the minimum breakdown length Lm when an electric field of 960 V / mm is applied is 30 mm, and the length in the stacking direction of the displacement-free region (the length in the stacking direction of each region) is less than 30 mm. In this way, the stacked body may be divided into a plurality of regions.
[0071]
Thus, the number of regions provided in the stacked body 4 may be determined so that the length in the stacking direction of the displacement-free region is set to be smaller than the minimum fracture length Lm. That is, the relationship between the total length L, the minimum fracture length Lm, and the number n of regions of the stacked body 4 is determined as a minimum integer value n satisfying L / n <Lm, and the total length of the stacked body 4 is divided into n equal parts. It is sufficient to set the area.
[0072]
The element 1 according to the present embodiment can be obtained, for example, by a method of sintering a laminate of ceramic green sheets used for manufacturing a ceramic capacitor or the like. Specifically, a step of creating a piezoelectric or electrostrictive ceramic powder, a step of adding an organic binder or the like to the powder and kneading to form a green sheet, and a metal electrode paste that becomes the partial electrode 7 on the surface of the obtained green sheet Forming the external electrode 9 so as to connect the partial electrodes 7 in parallel, the step of laminating the green sheets after printing, the step of sintering and integrating the laminate (raw laminate) And the process of manufacturing. When the green sheets after printing are stacked, the arrangement pattern of the green sheets is changed for each region. The external electrode 9 is formed for each region.
In the case of piezoelectric ceramics, finally, a polarization process step for applying a DC voltage between the external electrodes is added. Alternatively, the regions 21, 22, 23, and 24 can be separately laminated and integrally fired, and then the regions 21, 22, 23, and 24 can be joined with an adhesive.
[0073]
Thus, according to the present embodiment, the displacement non-occurrence areas 61, 62, 63, 64 are discontinuous between the areas 21, 22, 23, 24. Therefore, even if the entire length of the stacked body 4 in the stacking direction is formed long, it is possible to suppress the generated stress by suppressing the length in the stacking direction of the displacement non-occurrence regions 61, 62, 63, 64 to a small level. Generation and growth can be prevented.
[0074]
In each of the regions 21, 22, 23, and 24, the length in the stacking direction of the displacement-free regions 61, 62, 63, and 64 (the length in the stacking direction of the regions 21, 22, 23, and 24) is set to the minimum destruction. Since it is set to be smaller than the length, the generation and growth of cracks can be prevented more reliably.
[0075]
The first external electrode 36 and the third external electrode 38 are electrically connected via the partial electrode 7 of the second internal electrode layer 42 at the boundary end of the first region 21, and the second external electrode 37 and the fourth external electrode The electrode 39 is electrically connected through the partial electrode 7 of the first internal electrode layer 41 at the boundary end of the second region 22. Accordingly, the external electrode in the first region and the external electrode in the second region can be electrically connected via the partial electrode 7 without requiring a separate connection line, thereby simplifying the structure. Can do.
[0076]
Since the element 1 of this embodiment is obtained by changing the arrangement pattern of the internal electrode layers 3 between the regions 21, 22, 23, and 24 and stacking them, it is compared with the case where a large number of grooves are formed in the stacked body. Thus, the manufacturing burden is reduced, and industrial production can be easily performed.
[0077]
Next, a second embodiment of the present invention will be described based on FIG.
[0078]
FIG. 3 is a perspective view showing the laminate according to the second embodiment through a ceramic layer. The second embodiment is different from the first embodiment in the structure of the internal electrode layer at the boundary end, and the same reference numerals are given to the same configurations as those in the first embodiment, and the description thereof is omitted. Further, in the second embodiment, the structure of the internal electrode layer at the boundary edge between each of the four regions of the first embodiment is changed, but as a representative, the boundary between the first region and the second region. explain.
[0079]
As shown in FIG. 3, in the first region 21 of the stacked body 4, the second internal electrode layer 42 at the boundary end includes the fourth stacked axis in addition to the electrodeless portion 8 disposed on the second stacked axis 32. 34 has an electrodeless portion 8 (45) disposed on the upper surface. The first internal electrode layer 43 in the first region 21 adjacent to the second internal electrode 42 at the boundary end is disposed on the third stacked shaft 33 in addition to the electrodeless portion 8 disposed on the first stacked shaft 31. The electrodeless portion 8 (46) is provided.
[0080]
In the second region 22, the first internal electrode layer 41 at the boundary end includes the electrodeless portion 8 (on the first stacked shaft 31) in addition to the electrodeless portion 8 disposed on the third stacked shaft 33 ( 47). The second internal electrode layer 44 in the second region 22 adjacent to the first internal electrode layer 41 at the boundary end is formed on the second stacked axis 32 in addition to the electrodeless portion 8 disposed on the fourth stacked axis 34. It has the electrodeless part 8 (48) arrange | positioned.
[0081]
In the above configuration, the first external electrode 36 further extends along the first stacked axis 31 from the partial electrode 7 of the second internal electrode layer 42 at the boundary end of the first region 21, and the first external electrode 36 at the boundary end of the second region 22. Even when the first internal electrode layer 41 is reached, the first internal electrode layer 41 is provided with the non-electrode portion 47 disposed on the first laminated shaft 31. And the partial electrode 7 of the first internal electrode layer 41 are kept in an insulated state. Similarly, the second external electrode 37 further extends along the second laminated axis 32 from the partial electrode 7 of the first internal electrode layer 41 at the boundary end of the second region 22, and reaches the first internal electrode layer 41 at the boundary end. Even when the second internal electrode layer 44 in the adjacent second region 22 is reached, the second internal electrode layer 44 is provided with an electrodeless portion 48 disposed on the second stacked shaft 32. Therefore, the second external electrode 37 and the partial electrode 7 of the second internal electrode layer 44 are kept in an insulated state. The third external electrode 39 further extends along the third stacked axis 33 from the partial electrode 7 of the second internal electrode layer 42 at the boundary end of the first region 21, and is adjacent to the second internal electrode layer 42 at the boundary end. Even when the first internal electrode layer 43 in one region 21 is reached, the first internal electrode layer 43 is provided with the electrodeless portion 46 disposed on the third lamination axis 33. The third external electrode 38 and the partial electrode 7 of the first internal electrode layer 43 are kept in an insulated state. The fourth external electrode 39 further extends along the fourth stacked axis 34 from the partial electrode 7 of the first internal electrode layer 41 at the boundary end of the second region 22, and the second internal electrode layer at the boundary end of the first region 21. Even when the second internal electrode layer 42 is reached, the second internal electrode layer 42 is provided with the electrodeless portion 45 disposed on the fourth laminated shaft 34. The partial electrode 7 of the electrode layer 42 is kept in an insulated state.
[0082]
Therefore, the work of forming the external electrodes 9 (36, 37, 38, 39) on the side surfaces (side portions 4a, 4b, 4c, 4d) of the laminate 4 can be easily performed, and the productivity is improved. .
[0083]
Next, a third embodiment of the present invention will be described with reference to FIGS.
[0084]
FIG. 4 is a perspective view showing the laminate according to the third embodiment through a ceramic layer, and FIG. 5 is an external perspective view of FIG. In the third embodiment, grooves for stress relaxation are formed in the laminated body of the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. .
[0085]
As shown in FIG. 4, grooves 51 and 52 for relaxing stress are formed in the side portions 4 a, 4 b, 4 c and 4 d of the stacked body 4. The width (height in the stacking direction) of the grooves 51 and 52 is about several tens of μm.
[0086]
The groove 51 is formed in the ceramic layer 2 between the first internal electrode layer 5 in the second region 22 located at the boundary edge with the first region 21 and the second internal electrode layer 6 in the second region 22 adjacent thereto. It is formed in the side parts 4a and 4b. That is, the groove 51 is arranged in the vicinity of the first region 21 and on the extension line in the stacking direction of the displacement-free region of the first region 21 (on the first stacking axis 31 and the second stacking shaft 32). . For this reason, the groove 51 mainly contributes to the relaxation of the stress generated in the first region 21. The groove 51 is formed in the second region 22 instead of the first region 21. When the groove is formed in the first region 21, the external electrode 9 (the first external electrode 36 and the second external electrode 37) is placed on the groove. This is because it is necessary to consider the current-carrying stability of the external electrode 9 on the groove.
[0087]
The groove 52 is formed in the ceramic layer 2 between the second internal electrode layer 6 in the third region 23 located at the boundary end with the second region 22 and the first internal electrode layer 5 in the third region 23 adjacent thereto. It is formed in the side parts 4c and 4d. That is, the groove 52 is disposed in the vicinity of the second region 22 and on the extension line in the stacking direction of the displacement-free region of the second region 22 (on the third stacking shaft 33 and the fourth stacking shaft 34). . For this reason, the groove 52 mainly contributes to relaxation of the stress generated in the second region 22. The groove 52 is formed not in the second region 22 but in the third region 23. When the groove is formed in the second region 22, the external electrode 9 (the third external electrode 38 and the fourth external electrode 39) is placed on the groove. This is because it is necessary to consider the current-carrying stability of the external electrode 9 on the groove.
[0088]
The grooves 51 and 52 may be formed in the laminated body 4 after sintering, or may be formed in the raw laminated body before sintering. The grooves 51 and 52 are formed using a dicing saw, a wire saw, a laser processing machine, or the like. The method of forming the grooves 51 and 52 in the green laminate before sintering can easily perform the operation of forming the grooves 51 and 52 and the residue generated when the grooves 51 and 52 are formed. It is excellent in that distortion is eliminated during sintering.
[0089]
According to the present embodiment, the presence of the grooves 51 and 52 further reduces the generated stress, and can more reliably prevent the generation of cracks. In addition, since the relaxation of the stress by the grooves 51 and 52 is complementary, the number thereof is small and the manufacturing burden is small.
[0090]
Although not particularly illustrated, the tips of the grooves 51 and 52 can be formed in a curved surface.
[0091]
For example, when the tip of the groove has a corner, a crack may be generated and grow by using the corner as a trigger. On the other hand, if the tips of the grooves 51 and 52 are curved, there is no corner that triggers the generation of cracks, so the generation of cracks can be more reliably prevented.
[0092]
Further, the thickness of the ceramic layer 2 in which the grooves 51 and 52 are formed can be made larger than the thickness of the other ceramic layers 2.
[0093]
Thereby, the thickness of the ceramic layer 2 that does not have the grooves 51 and 52 can be set small, and the amount of displacement of the element can be increased while suppressing the magnitude of the voltage to be applied. By setting the thickness of the ceramic layer 2 to be formed large, the processing work of the grooves 51 and 52 can be easily performed, and industrial production becomes much easier.
[0094]
Next, an example of the shape pattern of the internal electrode layer 3 will be described with reference to FIG.
[0095]
6A to 6D, the stacked body 4 has a substantially prismatic shape, and the electrodeless portion 8 and the external electrode 9 are formed at the corner portions. The shape of the electrodeless portion 8 coincides with the cross-sectional shape of the laminate at the portion where no displacement occurs.
[0096]
The shape of the electrodeless portion 8 in FIG. 6A (the cross-sectional shape of the laminate in the portion where no displacement occurs) is a substantially square shape having two sides as the side surface of the laminate 4, and the electrodeless portion in FIG. 8 is a substantially triangular shape having two sides on the side surface of the laminate 4, and the shape of the electrodeless portion 8 in FIG. The cross-sectional shape of the laminated body) is a substantially sector shape having two sides on the side surface of the laminated body 4. Moreover, in FIG.6 (d), the corner | angular part of the laminated body 4 of FIG.6 (b) is chamfered, and the external electrode 9 is formed in this chamfered part 4e. In addition, FIG.6 (d) can also be applied to the structure of Fig.6 (a) or FIG.6 (c).
[0097]
Next, 4th Embodiment of this invention is described based on FIG.7 and FIG.8.
[0098]
FIG. 7 is a perspective view showing the laminated body according to the fourth embodiment through a ceramic layer, and FIG. 8 is an external side view of FIG. In the fourth embodiment, the stacked body is not divided into a plurality of regions, and the electrodeless portion is arranged on a stacking axis inclined with respect to the stacking direction. The same configuration as in the first embodiment is the same. Reference numerals are assigned and explanations thereof are omitted.
[0099]
As shown in FIGS. 7 and 8, the non-electrode portion 8 of the first internal electrode layer 5 and the non-electrode portion 8 of the second internal electrode layer 6 are respectively opposed surfaces substantially orthogonal to the stacking direction of the stacked body 4. Exposed. The electrodeless portion 8 of the first internal electrode layer 5 is disposed on the first stacking axis 71 inclined with respect to the stacking direction, and the electrodeless portion 8 of the second internal electrode layer 6 is tilted with respect to the stacking direction. It is arranged on the second lamination axis 72. The external electrode 9 is disposed on the side surface of the stacked body 4 where the non-electrode portion 8 is exposed.
[0100]
That is, each of the non-displacement portions is composed of two ceramic layers 65 and 66 that are adjacent to each other with the electrodeless portion 8 interposed therebetween and are continuous in the stacking direction.
[0101]
In the above configuration, as in the first embodiment, when a voltage is applied to the external electrode 9, stress is applied to the boundary between the portion sandwiched between two adjacent partial electrodes 7 and the portion not sandwiched between the ceramic layers 2. appear. The magnitude of the generated stress is the length in the stacking direction of the region in which the partial electrodes 7 and the non-electrode portions 8 are alternately stacked with the ceramic layer 2 sandwiched on the same stacking axis substantially parallel to the stacking direction. The length increases as the length increases.
[0102]
In this regard, in the present embodiment, the electrodeless portion 8 of the first internal electrode layer 5 is disposed on the first stacking axis 71 inclined with respect to the stacking direction, and the electrodeless portion 8 of the second internal electrode layer 6 is positioned. Are arranged on the second lamination axis 72 inclined with respect to the lamination direction. That is, the first stacking shaft 71 and the second stacking shaft 72 are inclined with respect to the stacking direction of the stack, and each displacement non-occurrence portion is composed of two ceramic layers 65 and 66 that are continuous in the stacking direction. Therefore, the length in the stacking direction of the portion where no displacement occurs can be kept short. Therefore, the stress generated in the stacking direction is reduced, and crack generation and growth can be prevented.
[0103]
In addition, you may form the groove | channel of 3rd Embodiment in this embodiment. In the first to fourth embodiments, the shapes of the partial electrode and the non-electrode portion of the internal electrode layer are not limited to the illustrated shapes.
[0104]
The present invention is not limited to the above-described embodiment described as an example, modifications thereof, and examples. That is, it is needless to say that various modifications can be made according to the design and the like as long as the technical idea according to the present invention is not deviated from other than the above-described embodiment.
[0105]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a ceramic laminated electromechanical transducer that is industrially easy to produce and can prevent the occurrence of cracks when an electric field is applied.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a first embodiment of a ceramic laminated electromechanical transducer according to the present invention.
FIG. 2 is a perspective view seen through a ceramic layer of the laminate of FIG.
FIG. 3 is a perspective view showing a laminated body according to a second embodiment through a ceramic layer.
FIG. 4 is a perspective view showing a laminated body according to a third embodiment through a ceramic layer.
5 is an external perspective view of FIG. 4; FIG.
6 is a cross-sectional view showing an example of a shape pattern of an internal electrode layer, where (a) is an example of a substantially square electrodeless portion, (b) is an example of a substantially triangular electrodeless portion, and (c). Is an example of a substantially fan-shaped electrodeless portion, and (d) is an example in which an external electrode is formed on a chamfered portion.
FIG. 7 is a perspective view showing a laminated body according to a fourth embodiment through a ceramic layer.
8 is an external side view of FIG. 7. FIG.
[Explanation of symbols]
1 Ceramic laminated electromechanical transducer
2 Ceramic layer
3 Internal electrode layer
4 Laminate
4a, 4b, 4c, 4d The side part of a laminated body
5 First internal electrode layer
6 Second internal electrode layer
7 Partial electrodes
8 No electrode part
9 External electrode
21 First area
22 Second area
23 Third area
24 4th area
25, 26, 27 border
31 First laminated shaft
32 Second laminated shaft
33 Third lamination axis
34 Fourth lamination axis
36 First external electrode
37 Second external electrode
38 Third external electrode
39 Fourth external electrode
51, 52 groove
61, 62, 63, 64 Displacement-free region (displacement-free portion)
71 First laminated axis
72 Second laminated axis

Claims (14)

A plurality of ceramic layers made of a material that is displaced by application of an electric field; a plurality of internal electrode layers alternately stacked with the ceramic layers; and a pair of external electrodes, and the pair of external electrodes. Each of the external electrodes is a ceramic laminated electromechanical transducer that is alternately electrically connected to the plurality of internal electrode layers,
2. The ceramic laminated electromechanical transducer according to claim 1, wherein the laminated body has at least four displacement-free portions that do not cause mechanical displacement in the laminating direction even when the electric field is applied. A plurality of ceramic layers made of a material that is displaced by application of an electric field; a plurality of internal electrode layers alternately stacked with the ceramic layers; and a pair of external electrodes, and the pair of external electrodes. Each of the external electrodes is a ceramic laminated electromechanical transducer that is alternately electrically connected to the plurality of internal electrode layers,
The laminate includes a displacement generation region that causes a mechanical displacement in the stacking direction in accordance with the application of the electric field, and a displacement non-occurrence region that does not cause a pair of mechanical displacements corresponding to the formation site of the pair of external electrodes. Have
Each of the pair of non-displacement regions has at least two non-displacement portions,
The two displacement non-occurrence portions are arranged such that, at each boundary, the cross section of the boundary end of one displacement non-occurrence portion is completely deviated from the extension in the stacking direction of the cross section of the boundary end of the other displacement non-occurrence portion. Or a ceramic laminated electromechanical transducer, characterized by being in a discontinuous state arranged partially overlapping. A ceramic laminated electromechanical transducer according to claim 2,
The length of each displacement-free portion in the stacking direction is set to be smaller than the minimum fracture length at which a crack is generated in each region when a predetermined electric field is applied to the ceramic layer. Multilayer electromechanical transducer. A ceramic laminated electromechanical transducer according to claim 2,
Each of the displacement-free portions is composed of two ceramic layers that are continuous in the stacking direction. The ceramic laminated electromechanical transducer according to any one of claims 1 to 4,
Each of the pair of external electrodes is continuously formed to be inclined with respect to the stacking direction. A ceramic laminated electromechanical transducer according to any one of claims 1 to 5,
A multilayer ceramic electromechanical transducer comprising: a ceramic green sheet for forming the ceramic layer; and a laminate composed of a metal paste for forming the internal electrode layer; A ceramic laminated electromechanical transducer according to any one of claims 1 to 5,
2. A ceramic laminated electromechanical transducer having a structure in which each laminated body region having a plurality of displacement-free portions is integrally fired in advance, and then these regions are joined with an adhesive. The ceramic laminated electromechanical transducer according to any one of claims 1 to 4,
By electrically connecting one external electrode in each stacked body region to an internal electrode layer in the other stacked body region between adjacent stacked body regions in the stacking direction at the boundary, A ceramic laminated electromechanical transducer element characterized by performing connection. The ceramic multilayer electromechanical transducer according to claim 8,
The ceramic laminate type electromechanical transducer according to claim 1, wherein the displacement-free portion of one of the adjacent laminate regions extends in the stacking direction beyond the boundary and reaches a predetermined position in the other region. A ceramic multilayer electromechanical transducer according to any one of claims 1 to 5, claim 8, and claim 9,
The laminated body has a substantially prismatic shape, and the displacement-free portion and the external electrode are formed at corner portions thereof. A ceramic multilayer electromechanical transducer according to any one of claims 1 to 5, claim 8, and claim 9,
2. The ceramic laminated electromechanical transducer according to claim 1, wherein a cross-sectional shape of the laminate in which the displacement does not occur is a triangular shape having two sides on the side of the laminate. A ceramic multilayer electromechanical transducer according to any one of claims 1 to 5, claim 8, and claim 9,
A multilayer ceramic cross-sectional electromechanical transducer according to claim 1, wherein a cross-sectional shape of the laminate in which no displacement occurs is a substantially sector shape having two sides on the side of the laminate. A ceramic laminated electromechanical transducer according to any one of claims 10 to 12,
The ceramic laminated electromechanical transducer, wherein the corner portion is chamfered and the external electrode is formed in the chamfered portion. A ceramic laminated electromechanical transducer according to any one of claims 1 to 13,
A multilayer ceramic electromechanical transducer element, wherein a groove for relaxing stress is formed on a side surface intersecting with a lamination direction of the laminate.

Images