JPH06296048A - Laminated type piezoelectric element - Google Patents

Abstract

PURPOSE:To provide a laminated type piezoelectric element at low cost by reducing the number of manufacturing processes. CONSTITUTION:In an element side face where an inner electrode 12 is exposed, conductive resin is applied to the edge face of the every other inner electrodes, non-conductive resin is provided between each conductive resin 13, and a resin sheathing, having conductivity alternately, is formed.

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 a large number of thin films of piezoelectric material are laminated and a longitudinal displacement can be obtained by applying a voltage.

[0002]

2. Description of the Related Art When manufacturing a laminated piezoelectric element, it is desirable that the internal electrodes have the same shape as the cross section of the element. This is because when the area of the internal electrodes is smaller than the cross-sectional area of the element as in a multilayer capacitor, electrolysis does not occur on the entire surface and stress concentration occurs at non-uniform portions. However, the connection method is difficult when the internal electrodes are arranged on the entire surface.
As disclosed in 354, it is necessary to perform insulation treatment outside the element.

That is, as shown in FIG. 6, an insulating layer 3 is formed every other layer on an internal electrode 2 exposed on one side surface of an element formed by laminating a piezoelectric material 1 and an internal electrode 2. Similarly, the insulating layers 3 are formed on the opposite side surface by shifting the layers and placing them one by one. When the external electrodes 4 are applied to the both side surfaces, the external electrodes 4 are connected to the exposed internal electrodes 2, and the internal electrodes are alternately connected to each other.

Several methods have been devised for forming the insulating layer 3. For example, a method of depositing an insulating material in the vicinity of exposed internal electrodes by using an electrophoretic method, or after forming an insulating layer on the entire side surface A general method is to expose the internal electrodes by making slits every other layer with a micro cutter or the like.

After the external electrode 4 is applied, it is finally covered with resin or the like for the purpose of protecting it from moisture and external damage.

[0006]

However, the laminated piezoelectric element having the above-mentioned structure must have the following steps in its manufacturing process. First, an insulating layer is formed every other layer on the internal electrodes exposed on one side surface of the element, and then baked,
Next, external electrodes are applied and fired. When the insulating layer is formed on the entire surface of the device, a step of forming a slit with a micro cutter is performed during this. The above work is also performed on the other side, and finally it is covered with resin or the like.

As described above, the number of manufacturing steps is large in the steps from the formation of the insulating layer to the exterior, which causes an increase in the cost of the laminated piezoelectric element.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to reduce the number of manufacturing steps of a laminated piezoelectric element and provide an inexpensive laminated piezoelectric element.

[0009]

In order to achieve the above-mentioned object, the laminated piezoelectric element of the present invention has a structure in which the inner electrodes of the laminated piezoelectric element are exposed on one end surface of every other inner electrode. A conductive resin is attached between the conductive resins, and a non-conductive resin is mounted between the conductive resins, and the conductive resin is placed on the end faces of every other internal electrode while being further displaced from the one side face. And a non-conductive resin is mounted between the conductive resins.

[0010]

In the laminated piezoelectric element of the present invention having the above-mentioned structure, the conductive resin is mounted on the outer surface of the end portion of the internal electrode, and the non-conductive resin is placed between the conductive resins. By mounting each of them, a resin exterior of the element is formed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

After mixing the piezoelectric material 11 containing lead zirconate titanate (PZT) as a main component to a desired composition, 850
5 parts by weight of a binder, a small amount of a plasticizer, and a defoaming agent are added to the powder calcined at 0 ° C., and dispersed in an organic solvent to form a slurry. This slurry is formed into a green sheet by a doctor blade method to a predetermined thickness. Palladium (Pd) paste was screen-printed as the internal electrodes 12 on the green sheet, and a predetermined number of punched out pieces were stacked and integrated by hot pressing. After degreasing,
Sintering was performed at about 1200 ° C., and as shown in FIG.
One internal electrode 12 is cut at a position where it is exposed on the surface every other layer, and temporary external electrodes 22 and 23 are applied and baked on both side surfaces thereof. Cut so that is exposed on the surface.

Epoxy-based cationic electrodeposition paint is used as the resin, and aluminum powder is used as the conductive filler.
A resin paint tank containing a conductive filler mixed with 80 g of aluminum powder per liter and a resin paint tank containing no conductive filler are prepared. Then, one side surface 25 of the sintered body 21 is masked with a tape or the like, and first, the sintered body 21 is submerged in a resin paint tank containing no conductive filler, and a temporary external electrode 22 is provided with a cathode of a DC power source and a copper plate. An anode is connected to each of the electrodes, and a voltage of 150 V is applied for 1 minute, so that the non-conductive resin 14 is electrodeposited on the internal electrodes 12 in alternate layers.

After washing with water, a cathode of a DC power source is connected to the temporary external electrode 23, the sintered body 21 is submerged in a resin paint tank containing a conductive filler, and the internal electrode is exposed by applying a voltage of 100 V for 2 minutes. When the conductive resin 13 is electrodeposited on the electrode 12 and washed with water, a layer of the conductive resin 13 and a layer of the non-conductive resin 14 are electrodeposited on the end face of the internal electrode 12 in alternate layers as shown in FIG. Become. When placed in a constant temperature bath in this state and heated at 160 ° C. for 30 minutes, adjacent electrodeposition layers are connected as shown in FIG. 4, and every other layer becomes a conductive exterior. Similarly, the conductive resin 13 and the non-conductive resin 14 are also electrodeposited on the opposite side surface 25 with respect to the side surface 24 to form a resin exterior.

When the sintered body 21 thus packaged is cut at the position shown by the dotted line A in FIG. 5 and the cut surface is further packaged by spray coating or the like, it is exposed on one side as shown in FIG. A conductive resin 13 and a non-conductive resin 14 are alternately mounted on the end face of each internal electrode 12 to be formed, and a similar resin sheath is formed on the other side face by further shifting it from one side face. It is possible to obtain a laminated piezoelectric element. The obtained laminated piezoelectric element is connected to each conductive layer by sticking a conductive tape according to the purpose or sandwiching it with a metal clip-like one on the side surface where the resin outer casing having the conductive layer is formed, It is used by having a function as a laminated piezoelectric element.

According to the present embodiment, the insulating layer and the external electrode are not formed on the element, and the exterior is directly applied, so that the number of manufacturing steps of the laminated piezoelectric element can be greatly reduced. In addition, since the lead portion is formed after the resin coating, no gap is created in the resin coating, and migration of internal electrodes caused by the ingress of moisture, that is, the insulation resistance between the electrodes is reduced, and a short circuit phenomenon is prevented. it can.

[0017]

As is apparent from the above description, according to the laminated piezoelectric element of the present invention, the conductive resin is mounted on the end face of every other internal electrode on the side surface of the element where the internal electrode is exposed. By mounting the non-conductive resin between the conductive resins, the resin exterior is directly formed on the element, so that the number of manufacturing steps can be significantly reduced and the manufacturing cost of the laminated piezoelectric element can be reduced. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a laminated piezoelectric element according to an example of the present invention.

FIG. 2 is a perspective view of a cut laminated sintered body.

FIG. 3 is a cross-sectional view of an electrodeposition layer after electrodeposition.

FIG. 4 is a cross-sectional view of an electrodeposition layer after heat curing.

FIG. 5 is a perspective view of a laminated sintered body after heat curing.

FIG. 6 is a cross-sectional view of a conventional laminated piezoelectric element.

[Explanation of symbols]

 11 piezoelectric material film 12 internal electrode 13 conductive resin 14 non-conductive resin

Claims (1)

[Claims] 1. A laminated piezoelectric element in which a piezoelectric material and internal electrodes are alternately laminated, wherein a conductivity is provided on an end face of every other internal electrode on one side surface where the internal electrode of the laminated piezoelectric element is exposed. Attach the resin, non-conductive resin between each conductive resin,
Further, on the other side, a conductive resin is mounted on the end faces of every other internal electrode which are further shifted with respect to the one side, and a non-conductive resin is mounted between the conductive resins. A laminated piezoelectric element.