JPS6086883A - Manufacture of electrostrictive-effect element - Google Patents

Abstract

PURPOSE:To form a favorable glass coated film by a method wherein, when glass powder is made to stick to the exposed parts of internal electrode layers by an electrophoresis method, the internal potential of parts of the exposed parts, where the glass powder is not stuck, is set at the same potential as that of an opposed electrode plate or at a potential close to that of the opposed electrode plate. CONSTITUTION:a laminated body 40 constituted by laminating alternately internal electrodes and electrostrictive material is placed in an electrified glass powder-containing suspension. The internal electrodes are made to expose at the end surfaces of the laminated body 40. A temporary external electrode 12 and a temporary external electrode 14 are provided at both sides of the laminated body 40 and the temporary external electrodes 12 and 14 are connected with the internal electrodes every one layer. A DC power source 33 is connected to the temporary external electrode 12 and an opposed electrode plate 31. The opposed electrode plate 31 and the temporary external electrode 14 are mutually connected and the opposed electrode plate 31 and the temporary external electrode 14 are both set at the same potential. By constituting in such a way, glass powder sticks to the internal electrodes connected with the temporary electrode 12 and the vicinities thereof. When this laminated body 40 is baked, the purposive insulating pattern can be accurately formed on the exposed electrodes, thereby enabling to improve the connection of the electrostrictive-effect element and external terminals.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electrostrictive element using the longitudinal effect, and its purpose is to selectively and reliably cover a portion of an exposed electrode with a glass film. , is to insulate.

For this purpose, the present inventors have proposed a construction method characterized by forming an insulating pattern by electrophoresis using a suspension containing electrically charged glass powder. The outline will be explained with reference to FIGS. 1 to 6. FIGS. 1 and 2 are external views showing the exposed end faces of the internal electrodes of the electrostrictive material laminate before the glass coating is applied. FIGS. 3 and 4 are external views of the end faces of a laminate of an electrostrictive material to which band-shaped glass powder is adhered and internal electrodes, as seen from the front and back sides. 1
All of the internal electrodes indicated by 6 are connected to the temporary external electrode 12, and by applying a DC voltage between the counter electrode and the external electrode 12 in a suspension containing charged glass powder, the internal electrode exposed portion 16 is connected to the temporary external electrode 12. Glass powder 11 is attached in a band shape to the ceramic around the ceramic. On the back end surface, glass powder 15 adheres to the internal electrode 13 connected to the temporary external electrode 14 and the ceramic around it. By firing and fixing this, a glass film is formed every other layer on the exposed portion of the internal electrode and the ceramic around it. By removing both ends, cutting into the final shape of the device, and forming external electrodes, a large number of internal electrodes can be connected every other layer. FIG. 5 is an external view showing the cutting position (dotted line area) of the electrostrictive material laminate on which the glass coating is formed.

FIG. 6 shows an electrostrictive effect element with electrical connections. 1
7 is an external electrode, and all internal electrodes 13 are connected to this external electrode. All internal electrodes indicated by 16 are connected to external electrodes on the back side. By applying a voltage between the positive side terminal 19 and the negative side terminal 20, the upper and lower protective film parts are removed (an electric field perpendicular to the internal electrode and associated strain is generated throughout the electrostrictive material, causing an electrostrictive effect. Operates as an element.

The problem with this method is that a small amount of glass powder adheres to the parts of the glass that should not be attached during electrophoretic deposition, that is, to the exposed parts of the internal electrodes that will be connected to the external electrodes that will be formed later. It is covered with a thin glass film. FIG. 7 is a sectional view of an electrostrictive element in which external electrodes are formed on the end face to which an unnecessary glass film is fixed. Numbers 11 and 15 in the figure are the original insulation coatings. 21 indicates an unnecessary glass film. When this is formed, the internal electrode 13 is not connected to the external electrode 17, and the internal electrode 16 is not connected to the external electrode 18. Reference numerals 19 and 20 indicate negative and positive external terminals, respectively.

The reason why glass powder adheres to unnecessary parts is that the dielectric constant of the ceramic material is high, and the potential of the entire electrostrictive material, including the internal electrodes that are not attached due to dielectric polarization, is almost the same as the potential of the internal electrodes that should be attached. This is because it becomes A case in which the electrophoresis method is applied to an electrostrictive material laminate having a dielectric constant of 2700 will be explained based on FIG. 3. The laminate and the counter electrode plate are placed in a suspension containing electrically charged glass powder, and 2000 mL is placed between the temporary external electrode 12' and the counter electrode plate.
VO) A DC voltage was applied. At that time, the potential difference between the counter electrode and the internal electrode exposed portion 13 was also quite large, 17V.
A portion of the charged glass powder also adhered to the western electrode exposed portion 13, which should not be allowed to adhere.

An object of the present invention is to provide a method for manufacturing an electrostrictive element that eliminates such drawbacks.

In the present invention, when glass powder is attached near the internal electrode on the end face of a laminate of an electrostrictive material and an internal electrode in a suspension containing charged glass powder, the glass powder is The potential of the internal electrodes to which no particles are attached is set to be the same potential as the counter electrode or a potential close to it. In order to have the same potential or close to the same potential as the counter electrode, this can be achieved by connecting it to the counter electrode, or by taking it out from a temporary external electrode made up of internal electrodes that do not have an antenna made of conductive material attached and placing it near the counter electrode. become. Figure 8,
FIG. 9 is an external view showing the arrangement of the electrophoretic device and the electrostrictive material laminate when connected and when the antenna is taken out, and the method of connecting them. However, FIG. 9 is a view from above. Reference numeral 12 denotes a temporary outer electrode that is a collection of internal electrodes to be attached, and 14 is a temporary outer electrode that is a collection of internal electrodes that are not to be attached. In FIG. 8, the temporary external electrode 14 is connected to the counter electrode 31 by a conducting wire 32. In FIG. In FIG. 9, an antenna 35 comes out from the temporary external electrode 14 and extends to the vicinity of the counter electrode. 33 is a DC power source, and 34 is a container that holds the suspension. As a result, no glass powder adheres to the internal electrode that is connected to the external electrode, and by firing, the desired insulation pattern of the glass coating as shown in Figures 3 and 4 is obtained. After cutting, the electrostrictive element is completely electrically connected by forming external electrodes.

Next, the present invention will be explained in detail according to examples.

Magnesium lead niobate (Pb(Mg%Nb%)Os)
A slurry was prepared by adding a small amount of an organic binder to an electrostrictive material pre-fired powder containing lead titanate (PbTiO,) as a main component and dispersing this in an organic solvent.

This slurry was coated onto a Mylar film to a thickness of several hundred microns using a casting film forming apparatus used in the production of ordinary multilayer ceramic capacitors and dried. This was peeled off from the film to obtain an electrostrictive material green sheet. Some of the green sheets were further screen-printed with platinum paste as internal electrodes. After stacking several dozen of these green sheets and pressing them together using a heat press, 1
It was fired at 250°C to obtain an electrostrictive material assembly. This was cut at a position where the internal electrodes were exposed on the surface every other layer, two temporary external electrodes were coated and baked, and the sides were further cut to expose the internal electrodes. The electrostrictive material laminate thus obtained is applied to electrophoresis. wc1 and 2 are perspective views showing exposed end faces of internal electrodes of this electrostrictive material laminate. A large number of internal electrodes 13 and 16 are alternately connected to two temporary external electrodes 14 and 12, respectively, on every other layer.

Next, a suspension containing charged glass powder is prepared by the following method. Zinc borosilicate crystallized glass powder 30g, ethanol 290mA! , 5% iodine ethanol solution 10fiA is mixed with a high speed homogenizer.

Iodine acts as an electrolyte, and the glass powder is positively charged. After applying ultrasound for 30 minutes, the suspension is allowed to stand for 30 minutes to remove the precipitate, and the remaining suspension is used.

Next, the configuration and connection method of the electrophoresis device will be explained according to FIG.

One side of the exposed end surface of the electrostrictive material laminate is covered with an adhesive tape to prevent it from getting wet with the suspension, and then submerged in a container filled with the suspension. A counter electrode plate 31 made of stainless steel, which is slightly larger than the end surface to which the laminate is to be attached, is sunk at a distance lα in front of the end surface to which the laminate is to be attached.

The counter electrode plate is connected to the positive terminal of a DC power supply, and the temporary external electrode 14 is connected to the counter electrode to have the same potential. Connect the temporary external power supply indicated by 12 to the negative terminal and connect it to 20 V.
Apply voltage for 300 seconds. When the suspension was removed from the suspension and dried, glass powder 11 having a width of 200 microns was obtained on the surface of the electrostrictive material on and around the exposed portion of the internal electrode, as shown in FIG.

After removing the adhesive tape on the back side, the glass film was baked by holding at 705° C. for 10 minutes to fix the glass film to the electrostrictive material.

Next, a glass coating is formed on the opposite side. First, protect the surface on which the film has already been formed by covering it with adhesive tape, then connect the temporary external electrode shown as number 14 in the figure to the negative terminal of the DC power supply, and apply voltage in the same way as the first time, as shown at 13. Glass powder is deposited on the exposed parts of the internal electrodes and the ceramic around them. This is fired in the same manner as the second time to form a band-shaped glass coating.

The electrostrictive material laminate with the glass coating formed on the front and back sides as described above is cut at the position shown by the dotted line in FIG. 5. The two small pieces with temporary external electrodes on both ends cannot be used, and the other small pieces serve as electrostrictive elements.

The obtained electrostrictive effect element can be easily electrically connected by forming two external electrodes on the front and back sides as shown in FIG. 6, and when a voltage is applied between the two external terminals 19 and 20. A uniform electric field is generated in the entire electrostrictive material except for the upper and lower protective film parts, and a strain of about 1/1000% is generated.

The electrically connected electrostrictive effect element is coated entirely with epoxy resin, including the exposed internal electrodes on the sides, to provide moisture resistance and insulation.

By the method of the present invention, it has become possible to selectively adhere glass powder to the internal electrode exposed portions of the end faces of the electrostrictive material laminate with high reliability. By firing and fixing this, a desired insulating pattern could be formed on the exposed electrode with high precision, and as a result, connections with external electrodes and external terminals were improved.

When the insulating film was formed using the method of the present invention, the number of connection failures was reduced from 25% to 3.

[Brief explanation of the drawing]

FIGS. 1 and 2 are external views showing the front and back end surfaces of a laminate of electrographic materials provided with temporary external electrodes 12 and 14 for the purpose of applying electrophoresis. In the figure, numbers 13 and 16 are internal electrode exposed parts. FIG. 3 and FIG. 4 are external views showing an electrostrictive material laminate in which glass powder is adhered to a part of the internal electrode exposed portion and the surrounding ceramic. Number 11 in the diagram,
15 shows attached glass powder. FIG. 5 is an external view showing a laminate in which glass powder is attached and fixed by firing, and its cutting position. FIG. 6 is a diagram showing electrically connected electrostrictive elements. In the figure, number 17 indicates an external electrode, and 20 indicates an external connection terminal. FIG. 7 is a cross-sectional view of an electrostrictive element in which electrical connection is impossible due to the formation of an unnecessary glass film. Number 21 in the figure indicates an unnecessary glass coating. FIG. 8 is an external view showing a method of connecting an electrophoresis device when the potential of the internal electrode to which no material is attached is set to the same potential as that of the counter electrode. Number 31 in the figure is a counter electrode plate. Reference numeral 32 indicates a conducting wire connecting the temporary external electrode 14 and the counter electrode plate. 33 and 34 indicate a DC power source and a container, respectively. FIG. 9 is an external view from above showing a method of connecting an electrophoresis device when the potential of the internal electrode to which no adhesion is made approaches the potential of the counter electrode. Number 35 in the figure indicates an antenna. Figure 1 Figure 1 Figure 3 Figure 5 Figure 6

Claims (1)

[Claims] In a suspension containing electrically charged glass powder, the glass powder is selectively deposited on a part of the internal electrode exposed at the end face of the laminate of the electrostrictive material and the internal electrode and the electrostrictive material in the vicinity thereof. A method for manufacturing an electrostrictive effect element comprising a step, wherein in the step, the potential of the internal electrode to which no glass powder is attached is set to the same potential as the counter electrode or a potential close to the same potential.