JP4403760B2 - Multilayer piezoelectric element and method for manufacturing the same - Google Patents

Abstract

The piezoelectric element (1) has a layered structure (10) with a number of piezoelectric layers (11) that can be expanded depending on an applied voltage and a number of. internal electrode layers (121,122) for applying a voltage to the piezoelectric layers, whereby all piezoelectric layers and all internal electrode layers are alternately stacked, and side electrodes (131,132) that lead electrically to the internal electrode layers an that are formed by sintering ultra fine metal particles.. - AN INDEPENDENT CLAIM is also included for a method of manufacturing an inventive laminated piezoelectric element.

Description

  The present invention relates to, for example, a fuel injection valve for automobiles, a precision positioning device such as an optical device, a driving element for vibration prevention, a multilayer piezoelectric element used for an ink jet printer, and a manufacturing method thereof.

A laminate formed by alternately laminating a piezoelectric layer that expands and contracts in response to an applied voltage and an internal electrode layer for supplying voltage to the piezoelectric layer, and is electrically connected to the internal electrode layer on a side surface of the laminate. A multilayer piezoelectric element having a side electrode is known.
Here, the side electrodes electrically connect internal electrode layers held at the same potential, and a voltage can be applied to each internal electrode layer via the side electrodes.
Then, an external electrode is provided on the outer side of the side electrode, and a lead wire or the like from the power source for driving the laminated piezoelectric element is attached to the external electrode (see Example 1 described later).

By the way, since a force is applied to the side electrode according to the expansion and contraction of the multilayer piezoelectric element, various proposals have been made for joining the side electrode and the multilayer body from the viewpoint of durability of the multilayer piezoelectric element.
For example, a method of baking a conductive paste containing glass frit at a high temperature in a reducing atmosphere, a method of providing a side electrode after setting the surface of the laminate to a surface roughness of 5 to 10 μm, a side electrode from a metal plating film and a metal vapor deposition film A method of configuring is known.

JP 2001-307548 A JP 2001-102647 A Japanese Patent No. 2536101

However, with the side electrode according to the conventional method, it has been difficult to obtain a highly reliable multilayer piezoelectric element.
That is, in the method using glass frit, it is necessary to bake the glass frit-containing conductive paste on the laminate at a high temperature at which the glass can be melted, and it is possible to employ an internal electrode layer made of Cu or Ni that oxidizes at high temperature in the laminate. It was difficult. Cu and Ni are inexpensive materials, and are very useful for reducing the cost of the multilayer piezoelectric element, so they are materials that should be adopted.
Although it is possible to fire a laminated body having a side electrode made of a glass frit-containing conductive paste and having an internal electrode layer containing Cu or Ni, heat treatment in a reducing atmosphere is necessary, which is very troublesome. there were.

  Further, as shown in FIG. 6 to be described later, in the region where the second side electrode is fabricated, the end surface of the first internal electrode layer exposed on the side surface of the laminate and the region where the first side electrode is fabricated In a laminated piezoelectric element in which an insulator is provided so as to cover the end face of the second internal electrode layer exposed on the side surface of the laminated body, generally used insulators (for example, silicone resin, epoxy resin, urethane resin, polyimide resin, etc.) The heat-resistant temperature is about 250 to 300 ° C. Therefore, the glass frit-containing conductive paste cannot be used for a laminated piezoelectric element having a structure using an insulator as shown in FIG.

  In addition, the method of providing the side electrode with the surface roughness of the laminated body being 5 to 10 μm is a method of making the contact area between the laminated body and the side electrode using the anchor effect so that they are in close contact with each other. From the viewpoint of bonding with the side electrode, it was not a highly reliable side electrode bonding method.

  In addition, the metal plating film and the metal vapor deposition film, such as metal wraps around the place that should not conduct during plating or vapor deposition, lowers the insulation of the part, impairs the reliability of the multilayer piezoelectric element, etc. There was a problem. In addition, masking processing to prevent wraparound is necessary, and it cannot be said that the working efficiency is high, and the cost is often high. In general, vapor deposition is a costly manufacturing method.

  The present invention has been made in view of such conventional problems, and provides a multilayer piezoelectric element having a low processing temperature at the time of manufacturing a side electrode, high reliability, easy manufacturing, and low cost, and a manufacturing method thereof. It is something to be offered.

According to a first aspect of the present invention, there is provided a laminate in which piezoelectric layers that expand and contract in response to an applied voltage and internal electrode layers for supplying voltage to the piezoelectric layers are alternately laminated, and the internal electrode layer on the side surface of the laminate. In a method of manufacturing a laminated piezoelectric element having a side electrode electrically conductive with
The side electrode is formed by applying an ultrafine particle dispersion containing ultrafine metal particles to form a coating layer, and sintering the coating layer,
As the metal ultrafine particles, those containing particles having a particle diameter of 1 to 100 nm in an amount of 30% by weight or more,
The content of the metal ultrafine particles in the ultrafine particle dispersion is 50% to 90% by weight with respect to 100% by weight of the dispersion,
The sintering temperature of the coating layer is 150 to 300 ° C., and the manufacturing method of the multilayer piezoelectric element is characterized in that (Claim 1).

In the first invention, the side electrode is prepared by sintering a coating layer coated with an ultrafine particle dispersion containing ultrafine metal particles.
By applying a dispersion of ultrafine metal particles to a desired position of the laminate, a coating layer in which ultrafine particles are densely packed can be produced. In order to obtain a side electrode by sintering the coating layer, the fine particles are fused while maintaining a fine packing state of the fine particles, thereby obtaining a dense, high-density metal layer similar to a plating film. be able to.
Further, in the first invention, since a bonding force acting on the metal-metal acts between the internal electrode layer and the side electrode, a state in which the internal electrode layer and the side electrode are in close contact with each other with a very strong force is obtained. be able to. Therefore, it becomes difficult for the side electrode to peel from the laminate.
In addition, the dispersion containing ultrafine metal particles can be sintered at a low temperature. Therefore, an internal electrode layer containing Cu or Ni that is oxidized at a high temperature can be employed.
In addition, a stacked piezoelectric element provided with an insulator having a low heat-resistant temperature can be manufactured (for example, a configuration according to FIG. 6 described later).
The dispersion of the ultrafine metal particles can be easily applied by a technique such as printing, and the shape of the coating layer can be easily controlled.

According to a second aspect of the present invention, there is provided a laminate in which piezoelectric layers that expand and contract in response to an applied voltage and internal electrode layers for supplying a voltage to the piezoelectric layers are alternately laminated, and the inner side on the side of the laminate. In a laminated piezoelectric element having a side electrode electrically connected to an electrode layer,
The piezoelectric layer is sandwiched between a first internal electrode layer and a second internal electrode layer. The first internal electrode layer is a first side electrode, and the second internal electrode layer is a second side electrode. Electrically conducting with
The first internal electrode layer is not exposed to the side surface of the multilayer body in the region where the second side electrode is fabricated, and the second internal electrode layer is the side surface of the multilayer body in the region where the first side electrode is fabricated. It is a partial electrode configuration that is not exposed to
Furthermore, the side electrode is formed by applying an ultrafine particle dispersion containing metal ultrafine particles to form a coating layer, and sintering the coating layer. The content of the metal ultrafine particles in the ultrafine particle dispersion is 50 to 90% by weight with respect to 100% by weight of the dispersion using 100 nm particles containing 30% by weight or more of the total, and the above The laminated piezoelectric element is characterized in that the sintering temperature of the coating layer is 150 to 300 ° C. ( Claim 4 ).

According to a third aspect of the present invention, there is provided a laminate in which piezoelectric layers that expand and contract in response to an applied voltage, and internal electrode layers for supplying voltage to the piezoelectric layers are alternately laminated, and the inner side on the side of the laminate. In a laminated piezoelectric element having a side electrode electrically connected to an electrode layer,
The piezoelectric layer is sandwiched between a first internal electrode layer and a second internal electrode layer. The first internal electrode layer is a first side electrode, and the second internal electrode layer is a second side electrode. Electrically conducting with
The first and second internal electrode layers have a whole surface electrode configuration formed in substantially the same shape and the same area as the piezoelectric layer,
In the region of the first internal electrode layer exposed on the side surface of the laminate in the region where the second side electrode was fabricated, and in the region of the second internal electrode layer where the first side electrode was fabricated An insulator is provided to cover the end face exposed on the side surface of the laminate,
Furthermore, the side electrode is formed by applying an ultrafine particle dispersion containing metal ultrafine particles to form a coating layer, and sintering the coating layer. The content of the metal ultrafine particles in the ultrafine particle dispersion is 50 to 90% by weight with respect to 100% by weight of the dispersion using 100 nm particles containing 30% by weight or more of the total, and the above The laminated piezoelectric element is characterized in that the coating layer has a sintering temperature of 150 to 300 ° C. ( Claim 5 ).

The second invention is a laminated piezoelectric element having a so-called partial electrode configuration, and the third invention is a so-called full-surface electrode configuration.
Regardless of the type and configuration of the element, the side electrode sintered with ultrafine metal particles is difficult to peel off from the surface of the laminate and is highly reliable. In addition, the dispersion containing ultrafine metal particles can be sintered at a low temperature, and an internal electrode layer containing Cu or Ni that is oxidized at a high temperature can be employed. As a result, the device can be easily manufactured.

  As described above, according to the first to third inventions, it is possible to provide a multilayer piezoelectric element and a method for manufacturing the same that have a low processing temperature when manufacturing the side electrode, are highly reliable, are easy to manufacture, and are inexpensive. it can.

An example of a method for manufacturing a multilayer piezoelectric element according to the first invention will be described.
A paste for internal electrode layers is printed on a green sheet for piezoelectric layers, and a desired number of these are stacked to produce an unfired laminate. As a green sheet used at this time, a sheet larger than the piezoelectric layer to be obtained can be used, and cut into pieces to have a necessary size after lamination or the like to produce an unfired laminate.
Next, the unfired laminate is fired. An ultrafine particle dispersion containing ultrafine metal particles is applied to the fired laminate to obtain a coating layer. For this application, screen printing or ink jet printing can be used. Thereafter, the fired laminated body provided with the coating layer at an appropriate temperature is heat-treated. Thereby, a side electrode is obtained, and a laminated piezoelectric element is obtained.
Moreover, as shown in Example 1 described later, an outer electrode made of a conductive resin such as a conductive epoxy resin can be provided on the outer side of the side electrode of the laminate. A lead wire from a power source for applying a voltage for driving the laminated piezoelectric element can be attached to the outer electrode.
Moreover, about this other manufacturing method, the effect concerning 1st invention can be acquired by providing a side surface electrode by the method concerning 1st invention. Here, the side electrode refers to a conductive structure in which the internal electrode layer is electrically connected and directly provided on the side surface of the laminate.

In this invention, the sintering temperature of the said coating layer is 150-300 degreeC .
As described above, according to the first invention, the side electrode can be manufactured by sintering at a low temperature. Therefore, a material containing Ni or Cu that is easily oxidized at a high temperature can be used as the material of the internal electrode layer. In the element configured as shown in FIG. 6 described later, the insulator is hardly deteriorated.
When the temperature is lower than 150 ° C., there is a possibility that the ultrafine particles are hardly sintered. When the temperature is higher than 300 ° C., it is difficult to sinter the ultrafine particles or it may take a long time to vaporize the dispersion. If the temperature is higher than 300 ° C., these materials may be oxidized if the internal electrode layer contains Cu or Ni. When the laminated piezoelectric element is provided with an insulator having a low heat-resistant temperature (for example, the configuration shown in FIG. 6 described later), the insulator deteriorates, or the temperature difference during cooling from a high temperature after sintering to room temperature Therefore, a large difference in thermal expansion (shrinkage) between the piezoelectric layer and the side surface electrode may occur, causing peeling.

Next, the metal ultrafine particles and the metal ultrafine particle dispersion will be described.
In the present invention, the ultrafine metal particles contain 30% by weight or more of particles having a particle diameter of 1 to 100 nm .
Fine particles made of metal and having a very small particle diameter can be sintered at a temperature much lower than the melting point. This is because when the average particle size is made sufficiently small, the proportion of the atoms with high energy states existing on the particle surface occupies the whole, so the surface diffusion of metal atoms becomes so large that it cannot be ignored. This is because the interface between the particles is stretched and sintering occurs.
When the ultrafine metal particles include particles having a particle size of less than 1 nm in an amount of 30% by weight or more, the particles having a particle size of less than 1 nm have extremely large surface diffusion, and the sintering speed of other particles having a particle size of 1 nm or more is high. There is a possibility that the difference becomes large and a uniform side electrode cannot be formed. When it is larger than 100 nm, the surface diffusion is small, and there is a possibility that the particles are hardly sintered.

Further, the metal ultrafine particles, Au, Ag, Cu, Pt, be made of Pd and an alloy thereof (claim 2).
All of these are good electrical conductors, and an excellent side electrode can be obtained.
In particular, Au, Ag, and Pt are materials having a high melting point, and the merit of the present invention that can be sintered at a low temperature is high as compared with a conventionally known method.

Further, the content of the metal ultrafine particles in the ultrafine particle dispersion is 50 to 90% (inner)% with respect to 100% by weight of the dispersion .
If it is less than 50% (inner)%, there is a possibility that a homogeneous side electrode cannot be formed after sintering. When the amount is more than 95% (inner)%, the viscosity of the ultrafine particle dispersion becomes high, which may make it difficult to apply.
Further, in order to appropriately apply the ultrafine particle dispersion to a predetermined position of the laminate, it is necessary to adjust the viscosity of the dispersion according to, for example, width accuracy and controllability of the film thickness. The range is preferably 1 to 500 Pa · s, more preferably 2 to 200 Pa · s. The viscosity can be controlled by adjusting the amount of the ultrafine metal particles.

The ultrafine particle dispersion in the first invention is preferably prepared by dispersing metal ultrafine particles in a solvent, and the dispersion preferably uses a solvent containing an organic solvent. It is desirable that the organic solvent evaporates quickly in the heat treatment for sintering, and is stable to the extent that thermal decomposition does not occur during the evaporating, and has an appropriate viscous state when forming the coating layer. It is preferable to select a solvent capable of maintaining the temperature.
For example, a relatively high boiling nonpolar or low polarity solvent that does not easily evaporate near room temperature, such as terpineol, mineral spirits, xylene, toluene, ethylbenzene, mesitylene, etc. can be suitably used. Hexane, heptane, octane, decane, dodecane, cyclohexane, cyclooctane, and the like.

  In addition to the ultrafine metal particles and the solvent for dispersing the ultrafine particle dispersion, the ultrafine particle dispersion prevents the formation of aggregates of the ultrafine metal particles and obtains a homogeneous dispersion state. As a possible group, a compound having a group containing nitrogen, oxygen, or sulfur element can be mixed.

Further, the internal electrode layer, one or both of Cu or Ni, it is preferable that comprising more than 80 wt% of the total weight internal electrode layer (claim 3).
Thereby, an internal electrode layer can be comprised with an inexpensive material. The internal electrode layer can be composed of Cu alone or Ni alone. Further, the internal electrode layer can be composed of an alloy of both, and may further contain materials other than Cu and Ni.

In the second and third inventions, the multilayer piezoelectric element can be configured by stacking a required number of piezoelectric layers in a lump. Or it can be a unit stacking type.
Here, the unit stacking type is a unit in which an appropriate number of piezoelectric layers are stacked and stacked in a desired number to form one large stacked piezoelectric element.

Example 1
The laminated piezoelectric element according to the present invention will be described.
As shown in FIG. 1, the multilayer piezoelectric element 1 according to this example includes a piezoelectric layer 11 that expands and contracts according to an applied voltage, and first and second internal electrode layers 121 and 122 that supply voltage to the piezoelectric layer 11. And the side electrodes 101 and 132 electrically connected to the internal electrode layers 121 and 122 on the side surfaces 101 and 102 of the laminate 10.
In manufacturing the laminated piezoelectric element 1, the side electrodes 131 and 132 are formed by applying an ultrafine particle dispersion containing metal ultrafine particles to form a coating layer, and sintering the coating layer.

Details will be described below.
As shown in FIG. 1, the multilayer piezoelectric element 1 according to this example is configured by alternately stacking piezoelectric layers 11 and first and second internal electrode layers 121 and 122 and providing dummy layers 119 at both ends in the stacking direction. The laminated body 10 is formed.
The end surface of the first internal electrode layer 121 is electrically connected to the first side electrode 131 on the first side surface 101 of the multilayer body 10, and the end surface of the second internal electrode layer 122 is connected to the second side electrode 132 on the second side surface 102. Conducts electrically.
The first internal electrode layer 121 is not exposed to the side surface 102 of the multilayer body 10 in the region where the second side electrode 132 is formed, and the second internal electrode layer 122 is the multilayer body in the region where the first side electrode 131 is formed. 10 side surfaces 101 are not exposed. That is, the multilayer piezoelectric element 1 according to this example has a partial electrode configuration.
That is, as shown in FIGS. 2A and 2B, the piezoelectric layer 11 has left portions 110 that do not form the internal electrode layers 121 and 122 on the left and right. This piezoelectric layer 11 is laminated to form a laminated body 10 as shown in FIGS.

  External electrodes 141, 142 are provided outside the first and second side electrodes 131, 132, and lead wires 152 are connected thereto with a conductive adhesive 151, and the lead wires 152 are not shown in the figure. Connect to. By energizing from an external power source, the first and second internal electrode layers 121 and 122 are energized through the external electrodes 141 and 142 and the first and second side electrodes 131 and 132.

The piezoelectric layer 11 and the dummy layer 19 are made of PZT (lead zirconate titanate), the internal electrode layers 121 and 122 are Ag-Pd electrodes, and the external electrodes 141 and 142 are made of epoxy resin containing conductive particles made of Ag. .
The first and second side electrodes 131 and 132 are formed by sintering ultrafine metal particles. Here, the ultrafine metal particles are made of silver.

A method for manufacturing the multilayer piezoelectric element 1 according to this example will be described.
A green sheet for the piezoelectric layer 11 is prepared, a printing layer for the internal electrode layers 121 and 122 is formed on the surface of the green sheet for the piezoelectric layer 11, and a printing part 110 on which the printing layers are not formed on the left and right sides of the green sheet for the piezoelectric layer 11. To leave behind.
This printing layer is produced by printing a paste of Ag—Pd with an organic solvent on the surface of the green sheet for the piezoelectric layer 11 by screen printing.
Next, a predetermined number of the green sheets are laminated and pressure-bonded and fired to obtain a laminate 10 as shown in FIGS. Next, as shown in FIG. 5, an ultrafine particle dispersion is applied to predetermined positions on the side surfaces 101 and 102 of the laminated body 10 to form a coating layer 135.

The ultrafine particle dispersion is prepared by mixing metal ultrafine particles made of silver with an average particle diameter of 5 nm with 3 g of decane as an organic solvent in a ratio of 1 g of metal ultrafine particles and 1 g of alkylamine.
This ultrafine particle dispersion is applied to a predetermined position of the laminate 10 by screen printing or ink jet printing to produce a coating layer.
And it baked at the temperature of 250 degreeC for 30 minutes, and the side electrodes 131 and 132 were obtained.

Thereafter, a conductive epoxy adhesive containing silver for the outer electrodes 141 and 142 was applied by screen printing and cured at 150 ° C. for 60 minutes.
Subsequently, the lead wire 152 was connected using the conductive epoxy adhesive 151 containing silver, and the laminated piezoelectric element 1 concerning FIG. 1 was obtained.

A continuous operation experiment was performed on the side electrodes 131 and 132 of the multilayer piezoelectric element 1 thus fabricated. As a result, the internal electrode layers 121 and 122 and the side electrodes 131 and 132 were not affected even after 1 × 10 ⁸ operations. The bond was retained.
In addition, the same test was performed on a conventionally known multilayer piezoelectric element made of a conductive epoxy adhesive containing silver. After 3 × 10 ⁷ operations, several internal electrode layers and side surfaces were obtained. Bonding with the electrode was weak, and a large resistance value was measured.
In this way, by forming the side electrode with ultrafine metal, it was possible to obtain a highly reliable bonding state between the internal electrode layer and the side electrode.

The effect concerning this example is demonstrated.
The side electrodes 131 and 132 according to this example are produced by sintering a coating layer coated with an ultrafine particle dispersion containing ultrafine metal particles made of silver.
In order to sinter silver by the conventional method, it is necessary to heat to 900 to 1000 ° C., but in this example, silver is sintered by heat treatment at a low temperature of 250 ° C. and 30 minutes, Side electrodes 131 and 132 can be manufactured.
This is achieved by using a screen dispersion or the like to obtain a coating layer in which silver ultrafine particles are dispersed in a finely packed state, and then sintering the coating layer to form a side electrode. In order to obtain 131 and 132, it is possible to obtain a silver layer that is dense and has a high density and is similar to a plating film by fusing the ultrafine particles while maintaining a fine packing state of ultrafine particles made of silver. .

  Further, in the multilayer piezoelectric element 1 according to this example, since the bonding force applied to the metal-metal acts between the internal electrode layers 121 and 122 and the side electrodes 131 and 132, the internal electrode layers 121 and 122 and the side surfaces A state in which the electrodes 131 and 132 are in close contact with each other with a very strong force can be obtained. Therefore, the side electrodes 131 and 132 are difficult to peel off from the stacked body 10.

  As described above, according to this example, it is possible to provide a multilayer piezoelectric element and a method for manufacturing the same, which have a low processing temperature when manufacturing the side electrode, are highly reliable, can be easily manufactured, and are inexpensive.

(Example 2)
In this example, a laminated piezoelectric element 1 having a full-surface electrode configuration will be described.
As shown in FIG. 6, the multilayer piezoelectric element 1 according to this example includes a piezoelectric layer 11 that expands and contracts according to an applied voltage, and first and second internal electrode layers 121 and 122 that supply voltage to the piezoelectric layer 11. And the first and second side electrodes 131 electrically connected to the first and second internal electrode layers 121 and 122 on the side surfaces 101 and 102 of the stacked body 10, respectively. 132.

The piezoelectric layer 11 is sandwiched between a first internal electrode layer 121 and a second internal electrode layer 122. The first internal electrode layer 121 is a first side electrode 131, and the second internal electrode layer 122 is a second side electrode. The first and second internal electrode layers 121 and 122 are electrically connected to the electrode 132, and have a full-surface electrode configuration having substantially the same shape and the same area as the piezoelectric layer 11.
An end surface of the first internal electrode layer 121 exposed on the side surface 102 of the stacked body 10 in a region where the second side electrode 132 is formed, and a first side electrode 131 of the second internal electrode layer 122. An insulator 16 is provided so as to cover the end face exposed on the side surface 101 of the laminated body 10 in the region where the structure is formed.
Further, the first and second side electrodes 131 and 132 are formed by sintering metal ultrafine particles.

  That is, the laminated piezoelectric element 1 of this example is a laminated body 10 in which piezoelectric layers 11 and first and second internal electrode layers 121 and 122 configured as full-surface electrodes are alternately laminated. , The portion of the side surface 101 where the second internal electrode layer 122 is exposed is cut to form a recess, and the insulator 16 is filled therein, so that the first side electrode 131 and the second internal electrode layer 122 are electrically connected. It is configured so as not to conduct. The same applies to the side surface 102, the first internal electrode layer 121, and the second side electrode 132.

When producing this multilayer piezoelectric element 1, the laminate 10 is produced in the same manner as in Example 1. At this time, the first and second internal electrode layers 121 and 122 are formed as full-surface electrodes.
Further, the first and second internal electrode layers 121 and 122 according to this example are made of Cu that is easily oxidized at a high temperature.
Then, prior to applying the ultrafine particle dispersion containing ultrafine metal particles, the end portion of the side surface 101 where the second internal electrode layer 122 is exposed, and the vicinity of the end portion of the side surface 102 where the first internal electrode layer 121 is exposed. Is cut into a dimple.
Next, an epoxy resin is filled, and heat curing is performed at 150 ° C. for 60 minutes to form the insulator 16.
Thereafter, a coating layer composed of an ultrafine particle dispersion was provided in the same manner as in Example 1, and the coating layer was sintered at a temperature of 250 ° C. for 30 minutes to form side electrodes 131 and 132.
Thus, the multilayer piezoelectric element 1 according to this example was obtained.

According to the manufacturing method of this example, since Cu is used as the first and second internal electrode layers 121 and 122, migration is less likely to occur compared to an internal electrode layer made of a metal material containing normal Ag. Thus, an element with low cost can be obtained. Furthermore, since the side electrodes 131 and 132 according to this example have a low firing temperature, the internal electrode layers 121 and 122 are hardly oxidized when the side electrodes 131 and 132 are manufactured.
The insulator 16 is made of an epoxy resin and has a low heat resistant temperature. According to this example, since the firing temperature of the side electrodes 131 and 132 is low, the insulator 16 hardly undergoes thermal degradation when the side electrodes 131 and 132 are manufactured.
In addition, the same effects as those of the first embodiment are obtained.

FIG. 7 shows a multi-layer piezoelectric element 1 having the same configuration as that of this example and having a different configuration. In the element 1, the first and second side electrodes 131 and 132 are not provided in the portion where the insulator 16 is provided.
In this multilayer piezoelectric element 1, after forming the side electrodes 131 and 132, a groove for providing the insulator 16 can be formed and the insulator 16 can be provided. Can also be applied when heat resistance is low.
Other details are the same as those of the multilayer piezoelectric element 1 according to this example.

6 and 7, depressions are provided in the side surfaces 101 and 102 of the laminated body 10 and the insulator 16 is disposed there. However, as shown in FIGS. , 132 can be provided on the side surfaces 101, 102 so as to cover the end surfaces of the first and second internal electrode layers 121, 122 that are not desired to be electrically connected to the side surfaces 101, 102.
8 shows an example in which the first and second side electrodes 131 and 132 are provided so as to cover the insulator 17, and FIG. 9 shows that the first and second side electrodes 131 and 132 are provided at the place where the insulator 17 is provided. There is no example.
In the multilayer piezoelectric element 1 of FIG. 8, the internal electrode having a larger area can be formed as compared with the elements shown in FIGS. 6 and 7, so that higher efficiency can be obtained.
In addition to the effect of FIG. 8, the multilayer piezoelectric element 1 of FIG. 9 can be provided with the insulator 17 after forming the side electrodes 131 and 132 as in FIG. Therefore, the present invention can also be applied when the insulator 17 has lower heat resistance than the side electrode sintering temperature.
Other details are the same as those of the multilayer piezoelectric element 1 according to this example.

FIG. 3 is a cross-sectional explanatory view of a multilayer piezoelectric element in Example 1. FIG. 3 is an explanatory diagram of an internal electrode layer provided with a piezoelectric layer and a retaining portion remaining in Example 1. FIG. 3 is a perspective development view showing a stacked state of piezoelectric layers in Example 1. FIG. 3 is an explanatory diagram of a stacked body before providing a side electrode in Example 1. FIG. 3 is an explanatory diagram when a coating layer serving as a side electrode is provided on a laminate in Example 1. Sectional explanatory drawing of the laminated piezoelectric element which is the whole surface electrode structure in Example 2, and provided the dent in the side surface and provided the insulator there. Sectional explanatory drawing of the laminated type piezoelectric element of Example 2 which is a whole surface electrode structure, provided a hollow in a side surface, provided an insulator there, and does not provide a side electrode in the position which provided this insulator. Sectional explanatory drawing of the laminated piezoelectric element which is the whole surface electrode structure in Example 2, and protruded from the side surface and provided the insulator. Sectional explanatory drawing of the laminated piezoelectric element which is the whole surface electrode structure in Example 2, and protruded from the side surface and provided the insulator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laminated piezoelectric element 10 Laminated body 101,102 Side surface 11 Piezoelectric layer 121,122 Internal electrode layer 131,132 Side electrode

Claims (5)

A laminate formed by alternately laminating a piezoelectric layer that expands and contracts in response to an applied voltage and an internal electrode layer for supplying voltage to the piezoelectric layer, and is electrically connected to the internal electrode layer on a side surface of the laminate. In a method of manufacturing a laminated piezoelectric element having a side electrode ,
The side electrode is formed by applying an ultrafine particle dispersion containing ultrafine metal particles to form a coating layer, and sintering the coating layer,
As the metal ultrafine particles, those containing particles having a particle diameter of 1 to 100 nm in an amount of 30% by weight or more,
The content of the metal ultrafine particles in the ultrafine particle dispersion is 50% to 90% by weight with respect to 100% by weight of the dispersion,
The method for producing a multilayer piezoelectric element, wherein the sintering temperature of the coating layer is 150 to 300 ° C. 2. The method of manufacturing a multilayer piezoelectric element according to claim 1, wherein the ultrafine metal particles are made of Au, Ag, Cu, Pt, Pd, and an alloy thereof. 3. The method for manufacturing a multilayer piezoelectric element according to claim 1, wherein the internal electrode layer contains one or both of Cu and Ni at 80% by weight or more of the total weight of the internal electrode layer. A laminate formed by alternately laminating a piezoelectric layer that expands and contracts in response to an applied voltage and an internal electrode layer for supplying voltage to the piezoelectric layer, and is electrically connected to the internal electrode layer on a side surface of the laminate. In a laminated piezoelectric element having a side electrode,
The piezoelectric layer is sandwiched between a first internal electrode layer and a second internal electrode layer. The first internal electrode layer is a first side electrode, and the second internal electrode layer is a second side electrode. Electrically conducting with
The first internal electrode layer is not exposed to the side surface of the multilayer body in the region where the second side electrode is fabricated, and the second internal electrode layer is the side surface of the multilayer body in the region where the first side electrode is fabricated. It is a partial electrode configuration that is not exposed to
Furthermore, the side electrode is formed by applying an ultrafine particle dispersion containing metal ultrafine particles to form a coating layer, and sintering the coating layer. The content of the metal ultrafine particles in the ultrafine particle dispersion is 50 to 90% by weight with respect to 100% by weight of the dispersion using 100 nm particles containing 30% by weight or more of the total, and the above A multilayer piezoelectric element, wherein the coating layer has a sintering temperature of 150 to 300 ° C. A laminate formed by alternately laminating a piezoelectric layer that expands and contracts in response to an applied voltage and an internal electrode layer for supplying voltage to the piezoelectric layer, and is electrically connected to the internal electrode layer on a side surface of the laminate. In a laminated piezoelectric element having a side electrode,
The piezoelectric layer is sandwiched between a first internal electrode layer and a second internal electrode layer. The first internal electrode layer is a first side electrode, and the second internal electrode layer is a second side electrode. Electrically conducting with
The first and second internal electrode layers have a whole surface electrode configuration formed in substantially the same shape and the same area as the piezoelectric layer,
In the region of the first internal electrode layer exposed on the side surface of the laminate in the region where the second side electrode was fabricated, and in the region of the second internal electrode layer where the first side electrode was fabricated An insulator is provided to cover the end face exposed on the side surface of the laminate,
Furthermore, the side electrode is formed by applying an ultrafine particle dispersion containing metal ultrafine particles to form a coating layer, and sintering the coating layer. The content of the metal ultrafine particles in the ultrafine particle dispersion is 50 to 90% by weight with respect to 100% by weight of the dispersion using 100 nm particles containing 30% by weight or more of the total, and the above A multilayer piezoelectric element, wherein the coating layer has a sintering temperature of 150 to 300 ° C.

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