JPH09172209A - Multilayer piezoelectric device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer piezoelectric device having strong adhesion between piezoelectric material layers, preventing the piezoelectric material layer and an inner electrode layer from pealing off and having good mechanical strength. SOLUTION: A multilayer piezoelectric device 1 is formed by alternately providing piezoelectric material layers 2 made of piezoelectric ceramic and inner electrode layers 3 made of conductive material. The internal electrode layer 3 is provided by printing conductive material paste on the piezoelectric material layer 2. The internal electrode layer 3 has an electrode portion 3a (printed portion) continuously forming internal electrodes on the surface and a non-electrode portion 3b (non-printed portion) serving as a gap on the surface. The internal electrode layer 3 connects piezoelectric material layers 2, 2 putting the internal electrode layer 3 therebetween to each other through the non- electrode portion 3b.

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 in which piezoelectric material film layers and internal electrode layers are alternately stacked, and in particular, a displacement in the thickness direction can be obtained by a piezoelectric thickness sliding effect when a voltage is applied. And a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a piezoelectric material made of a piezoelectric ceramic material (for example, a material containing lead zirconate titanate PZT as a main component) is used as a piezoelectric element which generates a displacement by a piezoelectric thickness sliding effect when a voltage is applied. It is known that an internal electrode layer (for example, palladium) is printed on the membrane layer. In such a piezoelectric element, in order to obtain a larger displacement, a piezoelectric material film layer and an internal electrode layer are alternately stacked to form a laminated type.

In the laminated piezoelectric element in which the piezoelectric material film layers and the internal electrode layers are alternately stacked in this way, a large displacement amount can be obtained in the thickness direction, but the total thickness of the element is large. Tend to be thicker. Therefore, when manufacturing such a laminated piezoelectric element,
In order to form the piezoelectric material film layer as thin as possible, a sheet molding method is generally applied, and the method is as follows.

A piezoelectric ceramic material containing lead zirconate titanate PZT as a main component was mixed in a predetermined composition to obtain about 90
A slurry obtained by mixing powder preliminarily fired at a temperature of 0 ° C. and a binder, an additive such as a plasticizer, with silicon-treated P
Pour into the gap between the ET film and the doctor blade,
It is dried to obtain a green sheet having a thickness of about 100 μm.

Next, this green sheet is punched into a predetermined size and peeled off from the PET film, and then a palladium paste to be an internal electrode is thinly applied to the surface by a screen printing method with a thickness of about several μm,
Dry to form the internal electrode layer. After stacking the required number of sheets and pressing them with a hot press to integrate them, the binder component is removed at a temperature of about 500 ° C. and further sintered at 1200 ° C. for 2 hours to obtain a desired laminated piezoelectric element. Obtain a laminate.

[0006]

However, as described above, in the laminated piezoelectric element of the type in which the piezoelectric material film layers and the internal electrode layers are alternately stacked, the piezoelectric material film layers and the internal electrode layers are Since there is a certain limit to the adhesion strength, when stress is applied to the piezoelectric element due to actions such as mechanical processing or deformation by applying a voltage after sintering, the piezoelectric material will be applied from the part with low adhesion strength. There is a problem that delamination between the film layer and the internal electrode layer occurs, and eventually mechanical destruction occurs.

The present invention has been made in view of the above points, and has high adhesion strength between piezoelectric material film layers, prevents delamination between the piezoelectric material film layers and internal electrode layers, and improves mechanical strength. An object is to provide a high laminated piezoelectric element and a method for manufacturing the same.

[0008]

According to a first aspect of the present invention, there is provided a laminated piezoelectric element in which a piezoelectric material film layer made of a piezoelectric ceramic material and an internal electrode layer made of a conductive material are alternately laminated. The internal electrode layer has an electrode portion that continuously forms the internal electrode on its surface and a non-electrode portion that forms a gap on the surface, and the piezoelectric material film layers that sandwich the internal electrode layer are not connected to each other. The electrodes are connected to each other through the electrode portions.

According to the first aspect of the invention, the piezoelectric material film layers sandwiching the internal electrode layers are connected to each other through the non-electrode portions of the internal electrode layers, and the adhesion strength between the piezoelectric material film layers is dramatically increased. It is improved, the delamination between the piezoelectric material film layer and the internal electrode layer is prevented, and the mechanical strength is enhanced.

According to a second aspect of the present invention, in the laminated piezoelectric element according to the first aspect, the internal electrode layer is formed by applying a conductive material paste onto the piezoelectric material film layer by printing. Forming a pattern having a printed portion that constitutes the, and a non-printed portion that is a gap where the printing is not performed,
Piezoelectric material film layers sandwiching the internal electrode layers are connected to each other through a non-printed portion.

According to the second aspect of the invention, the internal electrode layer is
A conductive material paste is applied and formed on the conductive material film by printing, and is easily formed by printing, and the piezoelectric material film layers that sandwich the internal electrode layer are interconnected through the non-electrode portion of the internal electrode layer. To be done.

According to a third aspect of the present invention, in the laminated piezoelectric element according to the first or second aspect, the width of each non-electrode portion of the internal electrode layer and the pitch of the adjacent non-electrode portions are the same as those of the piezoelectric material film layer. The electric field that appears is set to a predetermined dimension such that it is substantially uniform throughout the layer.

According to the invention of claim 3, the width of each non-electrode portion of the internal electrode layer and the pitch of the adjacent non-electrode portions are
The electric field appearing in the piezoelectric material film layer is set to a predetermined dimension so as to be substantially uniform over the entire layer, and the portion that hinders deformation is not biased.

According to a fourth aspect of the present invention, in the laminated piezoelectric element according to the third aspect, the width of each non-electrode portion of the internal electrode layer is 2 to 100 μm and is equal to or less than the thickness of the piezoelectric material film layer. The pitch of the adjacent non-electrode portions is twice or more the width of the non-electrode portions.

According to the fourth aspect of the invention, since the width of the non-electrode portion is less than or equal to the thickness of the piezoelectric material film layer, it is easy to obtain comparable piezoelectric displacement due to the effect of the oblique component of the electric field. . Further, by making the width of each non-electrode portion as small as 2 to 100 μm and setting the pitch of the adjacent non-electrode portions to be twice or more the pitch of the non-electrode portions (gap width), no electric field is applied by the non-electrode portions. The area is reduced.

According to a fifth aspect of the present invention, in the laminated piezoelectric element according to the third or fourth aspect, the internal electrode layer has a uniform dimple-shaped non-electrode portion.

According to the fifth aspect of the invention, the electrode portions and the non-electrode portions of the internal electrode layers are randomly arranged without aligning the internal electrode layers with each other, and the portions that hinder the deformation are not biased. .

According to a sixth aspect of the present invention, in the laminated piezoelectric element according to any one of the first to fifth aspects, it is used in a head of an ink jet printer as an actuator for generating a pressure for ejecting ink. .

According to the invention of claim 6, the laminated piezoelectric element used in the head of the ink jet type printing apparatus functions as an actuator for generating a pressure for ejecting ink by the piezoelectric thickness sliding effect.

According to a seventh aspect of the present invention, a piezoelectric material film layer made of a piezoelectric ceramic material is provided on a surface of an electrode portion made of a conductive material and continuously forming an internal electrode layer on its surface. A first step of forming an internal electrode layer having a non-electrode portion to be a gap, and a second step of stacking the piezoelectric material film layers on which the internal electrode layer is formed and thermocompressing them to integrate them. And a process.

According to the invention of claim 7, in the first step, an electrode made of a conductive material on the piezoelectric material film layer made of a piezoelectric ceramics material and continuously forming an internal electrode layer on the surface thereof. An internal electrode layer having a portion and a non-electrode portion serving as a gap between the electrode portion is formed, and in a second step, the piezoelectric material film layers having the internal electrode layer formed are laminated and heated. It is crimped and integrated.

The invention of claim 8 is the method of manufacturing a laminated piezoelectric element according to claim 7, further comprising a third step of sintering the integrated laminate.

According to the invention of claim 8, in the third step, the integrated laminate is sintered to improve the adhesiveness.

According to a ninth aspect of the present invention, in the method of manufacturing a laminated piezoelectric element according to the seventh or eighth aspect, the first step forms the internal electrode layer by printing the electrode portion by screen printing.

According to the ninth aspect of the invention, in the first step, the electrode portions are printed by screen printing to form the internal electrode layers.

[0026]

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

FIG. 1 is a sectional view showing a schematic structure of a laminated piezoelectric element. In FIG. 1, the laminated piezoelectric element 1 is a piezoelectric ceramic material (for example, lead zirconate titanate PZ.
A piezoelectric material film layer 2 made of a material containing T as a main component, and a conductive material (for example, silver-palladium) as an internal electrode material.
And the internal electrode layers 3 of are alternately laminated.

The internal electrode layer 3 has an electrode portion 3a which continuously forms an internal electrode on its surface, and a non-electrode portion 3b which is a gap on the surface. Then, the piezoelectric material film layers 2 and 2 sandwiching the internal electrode layer 3 are connected to each other through the non-electrode portion 3b.

Specifically, the internal electrode layer 3 is formed by applying a conductive material paste on the piezoelectric material film layer 2 by printing by a screen printing method, and the conductive material paste is applied by printing. A printed portion (electrode portion 3a) that constitutes the internal electrode and a non-printed portion (non-electrode portion 3b) that serves as a gap in which printing with the conductive material paste is not performed.
The piezoelectric material film layers 2 and 2 are connected to each other through the non-printed portion. The internal electrode layer 3 is formed by printing in this manner to form the piezoelectric material film layer 2
It is not limited to the one formed above, but may be one independently formed into a plate shape or a film shape. In addition, the internal electrode layer 3
Needless to say, current cannot be energized unless it is a continuous pattern that is not divided in the middle.

Further, each non-electrode portion 3 of the internal electrode layer 3
The width of b and the pitch of the adjacent non-electrode portions 3b, 3b are set to predetermined dimensions such that the electric field appearing in the piezoelectric material film layer 2 becomes substantially uniform throughout the layer. That is, in the internal electrode layer 3, the width of each non-electrode portion 3b is 2 μm to 10 μm.
0 μm and not more than the thickness of the piezoelectric material film layer 2, and the pitch of the adjacent non-electrode portions 3b, 3b is at least twice the width of the non-electrode portions 3b (non-printed portions that serve as gaps). Has been done.

Therefore, since the width of the non-electrode portion 3b is equal to or less than the thickness of the piezoelectric material film layer 2, it is easy to obtain a comparable piezoelectric displacement due to the effect of the oblique component of the electric field. The width of the non-electrode portion 3b is 2 μm to 100 μm
By making the pitch of the non-electrode portions 3b, 3b adjacent to each other twice the gap width or more, the area where the electric field cannot be applied by the non-electrode portion 3b is made small. Then, the electric field is not only the component generated only in the vertical direction sandwiched between the electrode portions 3a, but also the component generated diagonally with the adjacent electrode portion 3a, and the leakage electric field protruding from the region sandwiched between the electrode portions 3a. Since components and the like are also present, a substantially uniform electric field is applied to the entire area of the piezoelectric material film layer 2 with the above-mentioned dimensions.

More specifically, the internal electrode layer 2 is
A print pattern 11 having a uniform dimple-shaped non-electrode portion 3b, which is formed by screen printing of the internal electrode layer 2
For example, as shown in FIG. 2, is a print pattern that does not particularly require alignment, and the black-filled circular portion 11a (dimple portion) is a non-printed portion and is a non-electrode portion.

Therefore, it is not necessary to pay particular attention to the relative positional relationship between the internal electrode layers 3 and 3 during the stacking work. In the case of the stacked structure, the electrode patterns of the internal electrode layers 3 are randomly arranged. As a result, the non-electrode portion 3b that inhibits the deformation due to the piezoelectric thickness sliding effect is not biased to a specific portion.

By the way, in general, the ratio (area) of the electrode portions 3a in the internal electrode layer 3 may be determined depending on the application of the laminated piezoelectric element 1, but the electric field is disturbed and the piezoelectric thickness is deformed by the sliding effect. Since it is desirable to increase the overlapping portion of the electrode portions 3a of the internal electrode layer 3 as much as possible so as not to hinder the internal electrode layer 3, for example, when the internal electrode layer 3 is used for the application in which stress hardly acts. Of the internal electrode layers may be formed by the screen printing method using a printing pattern in which most of the electrode portions are the electrode portions 3a and the non-electrode portions 3b are almost absent.

With the above structure, the internal electrode layer 3
However, the electrode portion 3 that continuously forms the internal electrode on its surface
a (printed portion) and the non-electrode portion 3 that becomes a gap on the surface
b (non-printed portion), and the piezoelectric material film layers 2 and 2 that sandwich the internal electrode layer 3 in the upper and lower sides are connected to each other through the non-electrode portion 3b. The adhesion strength between the material film layers 2 and 2 is remarkably improved, and thereby the adhesion strength between the piezoelectric material film layers 2 and 2 and the internal electrode layer 3 sandwiched therebetween is also improved. It is possible to prevent delamination between 2 and the internal electrode layer 3. Therefore, the mechanical strength of the laminated piezoelectric element 1 against deformation is also increased.

Further, when the laminated piezoelectric element 1 is manufactured, the internal electrode layer 3 printed by screen printing is
Since the pattern has a uniform dimple-shaped non-electrode portion and does not particularly require alignment, it is not necessary to consider the alignment of the patterns with respect to each other when laminating, and the internal electrode layer 3 is It can be easily formed by printing. In other words, no alignment is required means that the electrode portion 3a and the non-electrode portion 3b of the internal electrode layer 3 are randomly arranged.
As a result, the non-electrode portion 3b that may hinder the deformation due to the piezoelectric thickness sliding effect is not biased to a specific portion of the internal electrode layer 3, and the piezoelectric material does not hinder the deformation due to the piezoelectric thickness sliding effect. Membrane layer 2 and internal electrode layer 3
It is possible to prevent delamination between the and.

Next, a method of manufacturing the laminated piezoelectric element 1 will be described. —First Step— On a piezoelectric material film layer made of a piezoelectric ceramic material, an electrode portion made of a conductive material and continuously forming an internal electrode layer on its surface, and a non-electrode forming a gap between the electrode portions. And an internal electrode layer having a portion.

Specifically, first, 5 parts by weight of a powder obtained by mixing a piezoelectric ceramic material containing lead zirconate titanate (PZT) as a main component with a predetermined composition and then calcination at a temperature of 850 ° C. The binder, a small amount of plasticizer and a defoaming agent are added, and then dispersed in an organic solvent to form a slurry. This slurry is formed into a predetermined thickness by the doctor blade method to obtain a green sheet. Next, a silver-palladium paste which will be an internal electrode material is printed on this green sheet by a screen printing method using a plate having a printing pattern 11 as shown in FIG. —Second Step— The piezoelectric material film layers on which the internal electrode layers are formed are stacked, and they are thermocompression bonded to be integrated.

Specifically, after printing in the first step,
The green sheets printed with the internal electrode material are punched out into a predetermined size and shape, and the necessary number of punched out green sheets are stacked, and they are heat-pressed by a hot press to be integrated. —Third Step— In the second step, the laminated body integrated by thermocompression bonding is sintered.

Specifically, the laminated product integrated by thermocompression bonding by hot pressing in the second step is first subjected to 5
Degreasing is performed at a temperature of 00 ° C., and then sintering is performed at about 1200 ° C. —Fourth Step— The laminated sintered body obtained by sintering in the third step is subjected to necessary finishing according to the application.

Specifically, as finishing processing, for example, cutting and polishing, shot blasting and the like are performed.

The laminated sintered body thus subjected to the necessary finishing processing is used as an actuator for generating a pressure for ejecting ink by the piezoelectric thickness sliding effect in a print head of an ink jet type printing apparatus, for example. In addition, it can be used for various wide-ranging applications such as a similar actuator in a dot type print head.

In the above embodiment, the internal electrode layer 3
Has a uniform dimple-shaped non-electrode portion, but the present invention is not limited thereto, and if the alignment is not particularly required, instead of the dimple shape, for example, a mesh is used. It can also be formed into a stripe shape or a stripe shape.

Further, in the above-mentioned embodiment, the internal electrode layer is formed on the piezoelectric material film layer by printing by the screen printing method, but the formation of the internal electrode layer is not limited to the screen printing method. Not something
If the internal electrode layer has an electrode portion that continuously forms the internal electrode on its surface and a non-electrode portion that forms a gap on the surface, the internal electrode layer is sandwiched through the non-electrode portion. Since it is possible to connect the piezoelectric material film layers to each other, the internal electrode layers can be formed by a known method such as a baking method, a sputtering method, or a vapor deposition method.

[0045]

According to the first aspect of the invention, as described above, the piezoelectric material film layers sandwiching the internal electrode layers are mutually connected through the non-electrode portions of the internal electrode layers. The adhesion strength between the material film layers is dramatically improved, delamination between the piezoelectric material film layer and the internal electrode layer can be prevented, and the mechanical strength is increased.

According to the second aspect of the present invention, since the internal electrode layers are formed by applying the conductive material paste on the conductive material film by printing, the internal electrode layers can be easily formed by printing. Further, the piezoelectric material film layers sandwiching the internal electrode layers can be connected to each other through the non-electrode portions of the internal electrode layers.

According to a third aspect of the present invention, the width of each non-electrode portion of the internal electrode layer and the pitch of the adjacent non-electrode portions are set to a predetermined value such that the electric field appearing in the piezoelectric material film layer is substantially uniform throughout the layer. Since it is set to, the part that hinders deformation is not biased.

According to the fourth aspect of the present invention, the width of the non-electrode portion is set to be equal to or less than the thickness of the piezoelectric material film layer. Therefore, due to the effect of the oblique component of the electric field, comparable piezoelectric displacement can be easily obtained. Further, the width of each non-electrode portion is set to 2 to 100 μm, and the pitch of the adjacent non-electrode portions is set to be twice the width of the non-electrode portions or more, so that the area where the electric field is not applied by the non-electrode portions is reduced. Is possible.

According to the fifth aspect of the invention, since the internal electrode layer has a uniform dimple-shaped non-electrode portion,
The internal electrode layers can be easily manufactured without considering the mutual alignment of the internal electrode layers, and the electrode parts and the non-electrode parts are randomly arranged to prevent deformation due to the piezoelectric thickness sliding effect. The part to do is not biased.

The invention of claim 6 is used in the head of an ink jet type printing apparatus, and is made to function as an actuator for generating a pressure for ejecting ink, so that ink can be ejected easily.

According to a seventh aspect of the invention, in the first step,
An internal structure having an electrode part made of a conductive material and continuously forming an internal electrode layer on its surface, and a non-electrode part forming a gap between the electrode parts, on a piezoelectric material film layer made of a piezoelectric ceramic material. Forming an electrode layer and in a second step,
Since the piezoelectric material film layers on which the internal electrode layers are formed are laminated and they are thermocompression bonded to be integrated, the laminated piezoelectric element according to any one of claims 1 to 6 can be easily manufactured. .

Further, in the eighth aspect of the present invention, since the integrated laminate is sintered in the third step, the adhesion is improved.

According to a ninth aspect of the invention, in the first step,
Since the electrode portions are printed by screen printing to form the internal electrode layers, the internal electrode layers can be easily formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a laminated piezoelectric element according to the present invention.

FIG. 2 is a plan view of a print pattern of an internal electrode layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multilayer piezoelectric element 2 Piezoelectric material film layer 3 Internal electrode layer 3a Electrode part (printed part) 3b Non-electrode part (non-printed part) 11 Printing pattern

Claims (9)

[Claims] 1. A laminated piezoelectric element comprising a piezoelectric material film layer made of a piezoelectric ceramic material and an internal electrode layer made of a conductive material, which are alternately laminated, wherein the internal electrode layer has internal electrodes on its surface. That the piezoelectric material film layers that sandwich the internal electrode layer are connected to each other through the non-electrode portion. Characteristic multilayer piezoelectric element. 2. The internal electrode layer is formed by applying a conductive material paste onto the piezoelectric material film layer by printing, and serves as a printed portion forming the internal electrode and a gap where the printing is not performed. Form a pattern with non-printed parts,
The multilayer piezoelectric element according to claim 1, wherein the piezoelectric material film layers sandwiching the internal electrode layers are connected to each other through a non-printed portion. 3. The width of each non-electrode portion of the internal electrode layer and the pitch of adjacent non-electrode portions are set to a predetermined dimension such that an electric field appearing in the piezoelectric material film layer is substantially uniform throughout the layer. The laminated piezoelectric element according to claim 1 or 2, wherein 4. The internal electrode layer has a width of each non-electrode portion of 2 to 100 μm and not more than a thickness of the piezoelectric material film layer, and a pitch of adjacent non-electrode portions is a width of the non-electrode portion. 4. The laminated piezoelectric element according to claim 3, which is at least twice as large as the above. 5. The multilayer piezoelectric element according to claim 3, wherein the internal electrode layer has a uniform dimple-shaped non-electrode portion. 6. The laminated piezoelectric element according to claim 1, wherein the laminated piezoelectric element is used in a head of an ink jet printer as an actuator for generating a pressure for ejecting ink. 7. A non-electrode which is made of a conductive material on a piezoelectric material film layer made of a piezoelectric ceramic material, and which serves as a gap between electrode portions which continuously form internal electrode layers on the surface thereof. A first step of forming an internal electrode layer having a portion, and a second step of stacking the piezoelectric material film layers having the internal electrode layer formed thereon and thermocompressing them to integrate them. A method for manufacturing a laminated piezoelectric element, comprising: 8. The method for manufacturing a laminated piezoelectric element according to claim 7, further comprising a third step of sintering the integrated laminate. 9. The method of manufacturing a laminated piezoelectric element according to claim 7, wherein the first step forms the internal electrode layer by printing the electrode portion by screen printing.