JPH1126831A - Multilayer piezoelectric element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated composite piezo electric element which has less restrictions on the arrangement of the element to be connected with external electrodes and has less influences of vibration hindrance. SOLUTION: Internal electrodes 2a and 2b are alternately disposed as connected to external electrodes 4a and 4b respectively, while internal electrodes 2c and 2d are disposed as connected to external electrodes 4c and 4d, respectively. The external electrodes 4a, 4b, 4c and 4d are arranged on the same plane as a laminate 3, whereas the external electrodes 4c and 4d are arranged in the vicinity of resonance nodes of the laminate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated piezoelectric element used for a ceramic oscillator, a ceramic filter, various sensors and the like utilizing a piezoelectric resonance phenomenon. On the outside of the laminate,
The present invention relates to a laminated piezoelectric element having external electrodes connected to the internal electrodes.

[0002]

2. Description of the Related Art Hitherto, a laminated piezoelectric element has been used as a displacement element such as an actuator because its driving voltage can be reduced. In recent years, the stacked piezoelectric element can be used for a sensor element such as a piezoelectric transformer or an acceleration sensor because its capacitance value can be increased. By taking such a laminated structure, it is possible to obtain a piezoelectric element having excellent characteristics according to the application.

FIG. 5 is an overall perspective view showing a conventional typical laminated piezoelectric element, and FIG. 6 is a partially exploded perspective view showing some of its internal electrode layers. Laminate 103
Is formed by alternately laminating a plurality of piezoelectric layers 101 and a plurality of internal electrode layers having either the internal electrodes 102a or 102b. An external electrode 104a is provided so as to extend from one side surface of the laminate 103 to the upper surface thereof.
However, an external electrode 104b is formed so as to extend from the side opposite to the one side to the lower surface. The internal electrode layers having the internal electrodes 102a and the internal electrode layers having the internal electrodes 102b are alternately arranged, and as shown in FIG. 6, the internal electrodes 102a are externally connected to only the external electrodes 104a. The end on the electrode 104a side is extended to the side surface, and the internal electrode 102b is connected to the external electrode 104.
The end on the side of the external electrode 104b is extended to the side surface so as to be connected only to the terminal b. External electrodes 104a, 104
As b, a film electrode such as baked silver is used so as to maintain reliable contact with the internal electrodes 102a and 102b.

On the other hand, a composite laminated piezoelectric element aiming at realizing two elements having different roles with one element, for example, a series resonator and a parallel resonator are used as one element for a ladder filter. Japanese Unexamined Patent Publications Nos. Hei 1-8711 and Hei 5-299970 disclose such means. By realizing two elements having different roles with one element, the number of elements and the number of metal terminals for electrical connection between the elements are reduced.

[0005]

In the multilayer piezoelectric element shown in FIG. 5, the connection between the external electrode 104a and the outside,
The connection between 104b and the outside must be made on different surfaces of the multilayer body 103, and this limits the arrangement of the device using the multilayer piezoelectric element. Similarly, in the composite laminated piezoelectric element, the connection between each external electrode and the outside must be made on another surface of the laminated body, and the external electrodes are connected to the external electrodes in comparison with the non-composite laminated piezoelectric element. Due to the large number, the restrictions on the arrangement are more severe.

Further, in the case of a composite laminated piezoelectric element, since various vibrations are generated and combined depending on the pattern of the internal electrodes and the arrangement of the extraction electrodes, it is difficult to extract them as a single resonance.

The present invention has been made in view of the above-mentioned problems of the conventional multilayer piezoelectric element, and has as its object to provide a multilayer piezoelectric element with less restrictions on the arrangement of elements connected to external electrodes. It is. It is another object of the present invention to provide a composite laminated piezoelectric element which has less restrictions on the arrangement of elements connected to external electrodes and is less affected by vibration inhibition.

[0008]

In order to solve the above-mentioned problems, the present invention of claim 1 is directed to a laminated body formed by alternately laminating an internal electrode layer having an internal electrode and a piezoelectric layer; A pair of first external electrodes disposed on one outer surface perpendicular to the internal electrode layers of the laminate, wherein at least a part of the internal electrode layers has continuously adjacent internal electrode layers The internal electrodes are alternately connected to one of the pair of first external electrodes.

According to a second aspect of the present invention, the internal electrodes of each of the internal electrode layers are not arranged around the first external electrodes to which they are not connected. 5. The multilayer piezoelectric element according to item 1.

According to a third aspect of the present invention, the pair of first external electrodes are arranged along separate ridges perpendicular to the internal electrode layers of the laminate. 3. The multilayer piezoelectric element according to 1 or 2.

The present invention according to claim 4 comprises at least a pair of second external electrodes disposed on the one outer surface,
At least a part of the continuously adjacent internal electrode layers having the internal electrodes that are not connected to the first external electrodes is such that the internal electrodes of the internal electrode layers are in any of the pair of second external electrodes. The multilayer piezoelectric element according to any one of claims 1 to 3, wherein the piezoelectric elements are arranged so as to be connected alternately.

According to a fifth aspect of the present invention, in the fourth aspect, one of the pair of second external electrodes also serves as one of the pair of first external electrodes. It is a laminated piezoelectric element according to any one of the preceding claims.

According to a sixth aspect of the present invention, in the piezoelectric device according to the fourth or fifth aspect, the pair of second external electrodes are arranged near a resonance node of the multilayer body. Element.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall perspective view showing a composite laminated piezoelectric element according to a first embodiment of the present invention, and FIG. 2 is a partially exploded perspective view showing some of its internal electrode layers.

The laminate 3 is formed by alternately laminating a plurality of piezoelectric layers 1 and a plurality of internal electrode layers having any one of the internal electrodes 2a, 2b, 2c and 2d.
Along the opposing ridges on one side of the laminate 3,
External electrodes 4a and 4b are formed, and external electrodes 4c and 4d are formed in the same plane. The internal electrode layers having the internal electrodes 2a and the internal electrode layers having the internal electrodes 2b are alternately arranged in a range where the internal electrode layers having the internal electrodes 2c and 2d do not exist, as shown in FIG. The internal electrode 2a has a planar shape in which only the vicinity of the external electrode 4b is cut out so as to be connected only to the external electrode 4a, and the internal electrode 2b is connected only to the external electrode 4b so as to be connected only to the external electrode 4b. Has a notched planar shape. Further, the internal electrode layer having the internal electrode 2c and the internal electrode layer having the internal electrode 2d are formed by the internal electrodes 2a, 2b
Are arranged alternately in a range where no internal electrode layer having the external electrodes 4a, 4a, 4a, and 4a is connected so that the internal electrode 2c is connected only to the external electrode 4c as shown in FIG.
b, 4c and 4d, the external electrodes 4
c has a planar shape protruding only in the vicinity of the internal electrode 2d
Are connected to only the external electrode 4d, so that the external electrodes 4a,
Along the surface where 4b, 4c and 4d are formed, it has a planar shape protruding only near the external electrode 4d.

With the above configuration, the laminated piezoelectric element according to the present embodiment includes one laminated piezoelectric element having external electrodes 4a and 4b as electrodes, and external electrodes 4c and 4c.
Another laminated piezoelectric element having d as an electrode functions as a composite laminated piezoelectric element. That is, for example, by using an element using the external electrodes 4a and 4b as electrodes as a series resonator and an element using the external electrodes 4c and 4d as electrodes as a parallel resonator, the multilayer piezoelectric element in the present embodiment is It can be used as a composite laminated piezoelectric element for a ladder filter, with less restrictions on the arrangement of elements connected to external electrodes.

That is, by arranging a portion where the piezoelectric members are directly laminated with each other by the missing portion of the internal electrode and a portion where it is not, the separation between the layers is facilitated, and the four terminals can be pulled out from the same surface, and the same element can be obtained. Can have two resonator portions at the same time. This makes it possible to obtain a laminated piezoelectric element having no restriction on the take-out position as compared with the conventional laminated piezoelectric element.

As shown in FIG. 2, the external electrodes 4c,
By arranging 4d in the vicinity of the resonance node of the multilayer body 3, the composite multilayer piezoelectric element is less affected by vibration inhibition.

In the present embodiment, the external electrodes 4
Although a and 4b have been described as being formed along opposing ridges on one side of the laminated body 3, the invention is not limited to this, and they are arranged in the one side so that they do not interfere with each other. You only have to be done.

Further, in this embodiment, the shapes of the internal electrodes 2a, 2b, 2c, 2d have been described as shown in FIG. 2. However, the present invention is not limited to this. What is necessary is just to have the shape which does not contact the external electrode which is not connected.

Next, a method of manufacturing the laminated piezoelectric element according to the present embodiment will be described. The starting material is the composition formula Pb
A piezoelectric ceramic calcined powder represented by (Zr _0.53 Ti _0.47 ) O ₃ +0.5 wt% Cr ₂ O ₃ is slurried by adding a binder and a plasticizer, and then formed into a sheet by a doctor blade method. The piezoelectric layer 1 is obtained by cutting the obtained sheet into a predetermined size. A green body is obtained by printing the internal electrodes 2a, 2b, 2c, and 2d thereon and stacking and pressing them. This is heat-treated to remove the binder, and baked at a temperature of 1080 to 1140 ° C. for 1 hour. External electrodes 4a, 4b, 4c,
Apply 4d and bake. Thereafter, a DC electric field of 3 kV / mm is applied in silicon oil at 150 ° C. to perform polarization processing, whereby the laminated piezoelectric element according to the present embodiment is obtained.

Next, a second embodiment of the present invention will be described with reference to the drawings. This embodiment is different from the first embodiment in that the external electrodes 4a and 4a of the multilayer piezoelectric element in the first embodiment are described.
d is a common external electrode. In the following description, components that are not particularly described are the same as those in the first embodiment. FIG. 3 is an overall perspective view showing a composite laminated piezoelectric element according to a second embodiment of the present invention, and FIG. 4 is a partially exploded perspective view showing some of its internal electrode layers.

The laminate 13 is formed by alternately laminating a plurality of piezoelectric layers 11 and a plurality of internal electrode layers having any one of the internal electrodes 12a, 12b, 12c and 12d. External electrodes 14a and 14b are formed along opposing ridge lines on one side surface of the stacked body 13, and an external electrode 14c is formed in the same plane. The internal electrode layers having the internal electrodes 12a and the internal electrode layers having the internal electrodes 12b are alternately arranged in a range where the internal electrode layers having the internal electrodes 12c and 12d do not exist, as shown in FIG. The internal electrode 12a has a planar shape in which only the vicinity of the external electrode 14b is cut out so as to be connected only to the external electrode 14a, and the internal electrode 12b is connected to the external electrode 14a so as to be connected only to the external electrode 14b.
Only the vicinity has a notched planar shape. Further, the internal electrode layers having the internal electrodes 12c and the internal electrode layers having the internal electrodes 12d are alternately arranged in a range where the internal electrode layers having the internal electrodes 12a and 12b do not exist, and are shown in FIG. As described above, the internal electrodes 12c are connected only to the external electrodes 14c,
The external electrode 14c is located along the surface where the b and 14c are formed.
It has a planar shape protruding only in the vicinity, and has an internal electrode 12d
Is connected to the external electrode 14a so as to be connected only to the external electrode 14a.
Along the plane on which a, 14b, and 14c are formed, it has a planar shape protruding only near the external electrode 14a.

With the above configuration, the laminated piezoelectric element according to the present embodiment includes one laminated piezoelectric element having the external electrodes 14a and 14b as electrodes, and the external electrode 14
Another laminated piezoelectric element having the electrodes a and 14c as electrodes functions as a composite laminated piezoelectric element.
That is, for example, by using an element having the external electrodes 14a and 14b as electrodes as a series resonator and an element having the external electrodes 14a and 14c as electrodes as a parallel resonator, the multilayer piezoelectric element in the present embodiment is It can be used as a composite laminated piezoelectric element for a ladder filter, with less restrictions on the arrangement of elements connected to external electrodes.

That is, by arranging a portion where the piezoelectric members are directly laminated with each other by the missing portion of the internal electrode and a portion where it is not, the separation between the layers is facilitated, and the three terminals can be drawn out from the same surface, and the same element can be obtained. Can have two resonator portions at the same time. This makes it possible to obtain a laminated piezoelectric element having no restriction on the take-out position as compared with the conventional laminated piezoelectric element.

As shown in FIG. 4, the external electrode 14c
Is disposed near the resonance node of the laminate 13,
The composite laminated piezoelectric element is less affected by vibration inhibition.

In the present embodiment, the external electrode 1
4a and 14b have been described as being formed along opposing ridges on one side of the laminate 13; however, the invention is not limited to this. In other words, they are arranged within the one side so that they do not interfere with each other. All you have to do is do it.

Further, in this embodiment, the shapes of the internal electrodes 12a, 12b, 12c, and 12d have been described as shown in FIG. 4, but the present invention is not limited to this. What is necessary is just to have the shape which does not contact the external electrode which is not connected.

The multilayer piezoelectric element of the present invention has been described as a composite multilayer piezoelectric element having two pairs of external electrodes in the first and second embodiments described above. Abolish the electrodes 4c, 4d or 14c,
Connect the internal electrodes 2c, 2d or 12c to the external electrodes 4b, 4a
Alternatively, even in the case of a single laminated piezoelectric element connected to 14b, the effect that there is little restriction on the arrangement of elements connected to the external electrodes can be expected.

In the first and second embodiments described above, the laminated piezoelectric element of the present invention includes a pair of second external electrodes sharing one or one of them with the first external electrode. However, the present invention is not limited to this, and includes a plurality of pairs of second external electrodes, and a plurality of groups of continuously adjacent internal electrode layers correspond to the pair of second external electrodes for each group. (Internal electrodes are alternately connected to only one of the pair of second external electrodes), so that there are few restrictions on the arrangement of elements connected to the external electrodes, and three or more It is possible to provide a laminated piezoelectric element in which the above elements are combined.

[0032]

As is apparent from the above description, the present invention can provide a laminated piezoelectric element having less restrictions on the arrangement of elements connected to external electrodes.
In addition, it is possible to provide a composite laminated piezoelectric element in which there are few restrictions on the arrangement of elements connected to the external electrodes and the influence of vibration inhibition is small.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing a composite laminated piezoelectric element according to a first embodiment of the present invention.

FIG. 2 is a partially exploded perspective view showing some of the internal electrode layers shown in FIG.

FIG. 3 is an overall perspective view showing a composite laminated piezoelectric element according to a second embodiment of the present invention.

FIG. 4 is a partially exploded perspective view showing some of the internal electrode layers shown in FIG. 2;

FIG. 5 is an overall perspective view showing a typical conventional laminated piezoelectric element.

FIG. 6 is a partially exploded perspective view showing some of the internal electrode layers shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric layer 2a, 2b, 2c, 2d Internal electrode 3 Laminated body 4a, 4b, 4c, 4d External electrode 11 Piezoelectric layer 12a, 12b, 12c, 12d Internal electrode 13 Laminated body 14a, 14b, 14c External electrode 101 Piezoelectric Body layer 102a, 102b Internal electrode 103 Laminated body 104a, 104b External electrode

Claims (6)

[Claims] 1. A laminate formed by alternately laminating an internal electrode layer having an internal electrode and a piezoelectric layer, and a pair of ones disposed on one outer surface of the laminate perpendicular to the internal electrode layer. A first external electrode, wherein the internal electrodes of at least some of the internal electrode layers that are continuously adjacent to each other are alternately connected to one of the pair of first external electrodes. A laminated piezoelectric element, characterized in that: 2. The multilayer piezoelectric device according to claim 1, wherein the internal electrodes of each of the internal electrode layers are not arranged around the first external electrodes to which they are not connected. Body element. 3. The device according to claim 1, wherein the pair of first external electrodes are arranged to face each other along separate ridge lines perpendicular to the internal electrode layers of the laminate. Stacked piezoelectric element. 4. At least a portion of the at least one pair of second outer electrodes disposed on the one outer surface and having at least a part of the inner electrodes not connected to the first outer electrode is continuously adjacent to each other. 4. The internal electrode layer according to claim 1, wherein the internal electrode of the internal electrode layer is arranged so as to be alternately connected to one of the pair of second external electrodes. Laminated piezoelectric element. 5. The multilayer piezoelectric body according to claim 4, wherein one electrode of the pair of second external electrodes also serves as one electrode of the pair of first external electrodes. element. 6. The multilayer piezoelectric element according to claim 4, wherein the pair of second external electrodes are disposed near a resonance node of the multilayer body.