JPH04237172A - electrostrictive effect element - Google Patents

Abstract

PURPOSE:To obtain an electrostrictive effect element which hardly deteriorates in insulation resistance by a method wherein recesses slightly larger than, an insulating layer in cross section are provided to the side face of an outer electrode in contact with a laminate at the same pitch with the insulating layers concerned. CONSTITUTION:Recesses 4a, 50mum in depth and 100mum in width, are provided to an outer electrode 4 of metal plate such as stainless steel or the like at the same pitch with glass insulating layers 3 through etching, and the outer electrode 4 is pasted on a block 9 through a conductive adhesive agent intruding the glass insulating layers 3 into the recesses 4a so as to electrically connect inner electrodes 2 whose end faces are alternately exposed. Then, a joint 4b of the outer electrode 4 is cut off. In succession, the block 9 is cut into chips with a cutting machine equipped with wires 11 such as music wires so as not to cut the outer electrodes 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostrictive element in which electrostrictive material layers and internal electrode layers are alternately laminated, and particularly relates to the formation of external electrodes.

0002

2. Description of the Related Art Conventionally, a laminated type electrostrictive element has sheet-like electrostrictive material layers 1 and internal electrode layers 2 alternately laminated as shown in FIG. 6, with internal electrodes exposed on a pair of opposing sides. layer 2
One end of the electrode layer 2 is insulated differently from each other on a pair of side surfaces by a glass insulating layer 3, and the other end of the internal electrode layer 2, which is not insulated, is connected to an external electrode 4 provided on each side surface. . At this time, a conductive paste such as silver paste is used for the external electrode 4, and since this external electrode is formed by screen printing or the like, the electrostrictive material layer 1 and the non-insulated internal electrode layer 2 are
, and also on the glass insulating layer 3.

0003

[Problems to be Solved by the Invention] In the conventional structure described above, since the external electrode made of conductive paste is also formed on the glass insulating layer, (1) the thermal shrinkage rate of the glass insulating layer and the external electrode is Due to this difference, cracks occur in the glass insulating layer, and the insulation resistance of the glass insulating layer decreases significantly, impairing the reliability of the electrostrictive effect element.

(2) When a lead wire or the like is soldered onto an external electrode, the solder is applied to the glass insulating layer, and the heat of the solder causes cracks in the glass insulating layer, causing a significant decrease in the insulation resistance of the glass insulating layer, resulting in an electrostrictive effect. This has the disadvantage of impairing the reliability of the device.

An object of the present invention is to prevent the glass insulating layer from being affected by the material and shape of the external electrodes, and also by the heat of the solder when lead wires are soldered to the external electrodes. This provides an electrostrictive effect element with no deterioration in insulation resistance.

[0006]

[Means for Solving the Problems] The electrostrictive effect element of the present invention has a structure in which a plurality of electrostrictive material layers and internal electrode layers are alternately laminated. In an electrostrictive effect element in which an insulating layer is formed every other layer on the exposed part of the side surface, and an external electrode is formed on the opposite side surface to electrically connect internal electrode layers on which no insulating layer is formed, the electrode contacts the stack of external electrodes. The structure is characterized by having recesses on the side surface at the same pitch as the insulating layer and slightly larger than the cross section of the insulating layer.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a perspective view of an electrostrictive element according to an embodiment of the present invention. In the figure, 1 is a ceramic electrostrictive material layer made of lead zirconate titanate having a composite perovskite structure, 2 is an internal electrode layer using a silver-palladium alloy disposed to sandwich the electrostrictive material layer 1, 3 is a glass insulating layer that is deposited to insulate every other end face of the internal electrode layer 2, and 4 is provided with recesses 4a having the same pitch as the glass insulating layer 3 and slightly larger than the cross section of the glass insulating layer 3. This is an external electrode. At this time, the external electrode 4 is provided by electrically connecting every other internal electrode layer 2, and the glass insulating layer 3 is placed in the recess 4a.

Next, a method of manufacturing the first embodiment shown in FIG. 1 will be explained with reference to FIGS. 3 to 5. 3 to 5 are perspective views of the element shown in the order of steps to explain the method of manufacturing the electrostrictive element of the first embodiment.

First, a pre-fired ceramic powder using lead titanate or the like is prepared and dispersed in an organic solvent such as ethyl cellosolve together with a small amount of an organic binder such as polyvinyl butyral and a plasticizer such as dioctyl phthalate. Create a slurry. This slurry is made to flow down onto the surface of a polyester film moving at a constant speed by a slip casting method using a doctor blade to form a green sheet with a thickness of 70 μm. Next, this green sheet is peeled off from the polyester film surface, and then a green sheet 7 is prepared by cutting the green sheet into a size of 70 mm in length and 100 mm in width, as shown in FIG. 3(a). Next, a printing screen (not shown) having a mask pattern that does not allow the paste to pass through is coated with a mixed paste made by pasting a mixed powder of silver powder and palladium powder together with a vehicle, on one side of the green sheet 7 except for one end. After being applied, the internal electrode layer 2 is formed by drying.

Next, every other green sheet 7 on which the internal electrode layer 2 has been formed is rotated 180 degrees, and a desired number of sheets are stacked and pressed from above and below with a press to form a laminate 8 as shown in FIG. 3(b). form. Since this laminate 8 contains the above-mentioned organic binder and plasticizer, it is heated in a furnace to a temperature of 500° C. to evaporate the plasticizer and decompose and remove the organic binder. Next, this laminate 8 was fired according to the following firing profile (temperature 1, rising speed 5°C/min,
The temperature is increased to 120°C, maintained at 1,120°C for 2 hours, and then naturally cooled). The fired laminate 8 is cut into a block shape as shown in FIG. 4(a) using a cutting machine using wire 11 made of metal, such as piano wire, and then cut into a block shape as shown in FIG. 4(b). A block 9 is formed. At this time, the end surfaces 2a of the internal electrode layers 2 are exposed every other layer on the left and right surfaces of the block 9. Apply silver paste to the left and right surfaces including this end surface 2a, and
), a pair of temporary electrode layers 6 are formed.

Next, as shown in FIG. 5(a), a masking material 12, such as Teflon tape, is attached to the surface opposite to the surface on which the glass insulating layer is to be formed. Next, using the temporary electrode layers 6 formed on the left and right surfaces of the block 9, glass powder is deposited every other layer on the internal electrode layer 2 exposed on the unmasked surface of the block 9 by electrophoresis. After that, the glass powder is fired in a belt furnace (not shown), and
A glass insulating layer 3 is formed as shown in (a). Next, a glass insulating layer 3 is formed on the other surface in the same manner as in the previous step.

Next, as shown in FIG. 5(c), an external electrode 4 made of a metal plate such as stainless steel is formed with recesses of 50 μm in depth and 100 μm in width at the same pitch (approximately 200 μm) as the glass insulating layer 3 by etching. (thickness approximately 500μm),
A glass insulating layer 3 is provided in the recess 4a of the external electrode 4 to electrically connect the internal electrode layers 2 whose end faces are exposed every other layer.
Attach it to the block 9 using a conductive adhesive so as to push it in. Next, the connecting portion 4b of the external electrode 4 is cut.

Next, as shown in FIG. 5(d), the block 9 is cut into chips using a cutting machine using a wire 11 made of metal, such as piano wire, without cutting the external electrode 4. Through the above steps, the electrostrictive element shown in FIG. 1 is obtained.

FIG. 2 is a perspective view of a second embodiment of the present invention. In the figure, 1 is an electrostrictive material layer, 2 is an internal electrode layer, 3 is an insulating layer, and 4
is the external electrode. In this embodiment, one end of the external electrode is bent into an L-shape, and even if the electrostrictive element is covered with resin, the external electrode is exposed, making it easier to handle the electrostrictive element during the inspection process. This has the advantage of significantly reducing manufacturing man-hours.

[0015] In the above embodiment, the cross-sectional shape of the recess is described as being U-shaped, but the recess is not limited to this, as long as it is larger than the cross-section of the glass insulating layer, and may be semicircular, for example.

[0016]

Effects of the Invention As explained above, in the present invention, since the external electrode and the glass insulating layer are not in contact with each other, (1) the glass insulating layer is not affected by the material and shape of the external electrode, so the original properties of the glass insulating layer can be improved. (2) When soldering lead wires to external electrodes, the glass insulation layer is not affected by the heat of the solder, so there is no deterioration in insulation resistance of the glass insulation layer. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an electrostrictive element according to an embodiment of the present invention.

FIG. 2 is a perspective view of an electrostrictive element according to another embodiment of the present invention.

FIG. 3 is a step-by-step perspective view for explaining the manufacturing method of an electrostrictive element according to an embodiment of the present invention, in which part (a) is a green sheet on which internal electrodes are formed, and part (b) is a laminate. FIG.

FIG. 4 is a perspective view of the steps following FIG. 3 for explaining an embodiment of the present invention, and FIG.
Part (b) is a perspective view of the cut block, and part (c) is a perspective view of the block with temporary electrodes formed thereon.

5 is a perspective view in the order of steps following FIG. 4 for explaining an embodiment of the present invention, showing the steps of forming an insulating layer, forming an external electrode, and cutting out an electrostrictive element from a block; FIG.

FIG. 6 is a perspective view showing an example of a conventional electrostrictive effect element.

[Explanation of symbols]

1 Electrostrictive material layer 2 Internal electrode layer 3 Glass insulation layer 4 External electrode layer 4a Recessed part 6 Temporary electrode layer 7 Green sheet 8 Laminated body 9 Block 10 Wire 11 Masking material

Claims (1)

[Claims] 1. An insulating layer is formed every other layer on exposed portions of either side of the internal electrode layer exposed on opposing side surfaces of a laminate in which a plurality of electrostrictive material layers and internal electrode layers are alternately laminated. In the electrostrictive element, in which an external electrode electrically connecting the internal electrode layer on which no insulating layer is formed is formed on the opposing side surface, the insulating layer and An electrostrictive effect element characterized in that recesses are provided at the same pitch and slightly larger than the cross section of the insulating layer.