JPS6318353B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electrostrictive effect element using a longitudinal effect, and its purpose is to selectively and reliably cover a portion of an exposed electrode with a glass film. It is to cover and 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. All internal electrodes indicated by 16 are temporary external electrodes 12
By applying a DC voltage between the counter electrode and the external electrode 12 in a suspension containing electrically charged glass powder, glass powder 11 is applied in a strip shape onto the exposed internal electrode part 16 and the ceramic around it. is attached. 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 portions of the internal electrodes and the ceramic around them. 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. Reference numeral 17 denotes an external electrode, and all internal electrodes indicated by 13 are connected to this external electrode.
All internal electrodes indicated by 16 are connected to external electrodes on the back side. When a voltage is applied between the positive side terminal 19 and the negative side terminal 20, an electric field in a direction perpendicular to the internal electrode and the accompanying strain are generated in the entire electrostrictive material except for the upper and lower protective film parts, and the electrostrictive effect element is activated. operates as

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
This is because 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 approximately the same as the potential of the internal electrodes that are to be attached. 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 a layer is placed between the temporary external electrode 12' and the counter electrode plate.
A DC voltage of 20V was applied. At that time, the potential difference between the counter electrode and the internal electrode exposed portion 13 was quite large, 17 V, and some of the charged glass powder also adhered to the internal 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. FIG. 8 and FIG. 9 are external views showing the arrangement of the electrophoretic device and the electrostrictive material laminate and the method of connecting them when connected and when the antenna is taken out. However, FIG. 9 is a view from above. 12 is a temporary external electrode made up of internal electrodes to be attached; 1
Reference numeral 4 denotes a temporary external electrode made up of the internal electrodes that are not attached. In Fig. 8, temporary external electrode 1
4 is connected to the counter electrode 31 by a conducting wire 32. In FIG. 9, the 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 can be obtained, and the glass coating can be cut. By forming the rear external electrode, the electrostrictive element is completely electrically connected.

Next, the method of the present invention will be explained according to Examples.

Magnesium lead niobate (Pb (Mg1/3Nb2/3)
A slurry was prepared by adding a small amount of an organic binder to an electrostrictive material pre-fired powder containing lead titanate (PbTiO 3 ) and lead titanate (PbTiO ₃ ) as main components, 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 manufacture 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. Several ten of these green sheets were stacked, pressed together by heat press, and then fired at 1250°C to obtain an electrostrictive material laminate. This was cut at a position where the internal electrodes were exposed on the surface every other layer, and two temporary external electrodes were coated and baked.
Furthermore, the side surface was cut to expose the internal electrodes. The electrostrictive material laminate thus obtained is applied to electrophoresis. FIGS. 1 and 2 are perspective views showing exposed end faces of internal electrodes of this electrostrictive material laminate. A large number of internal electrodes 13, 16 are alternately connected to two temporary external electrodes 14, 12 at every other layer.

Next, a suspension containing charged glass powder is prepared by the following method. Mix 30 g of zinc borosilicate crystallized glass powder, 290 ml of ethanol, and 10 ml of 5% iodine ethanol solution using a high-speed homogenizer.
Iodine acts as an electrolyte, and the glass powder is positively charged. After applying ultrasound for 30 minutes,
Leave to stand for 30 minutes to remove the precipitate and use the remaining suspension.

Next, the configuration and connection method of the electrophoresis device will be explained with reference 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 the electrostrictive material laminate is submerged in a container 34 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 submerged at a distance of 1 cm 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 electrode indicated by 12 to the negative terminal,
Apply voltage of 20V for 300 seconds. When the electrostrictive material is removed from the suspension and dried, a wide area is formed on the surface of the electrostrictive material above and around the exposed internal electrodes, as shown in Figure 3.
A deposit of 200 microns of glass powder 11 was obtained.

After removing the adhesive tape on the back, heat at 705℃ for 10
The glass film was baked by holding for a minute 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 indicated by 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, indicated by number 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 first 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 has a shape of 2 as shown in FIG.
By forming two external electrodes on the front side and the back side, electrical connection is easily made, and two external terminals 19,
When a voltage is applied between 20 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, the desired insulation pattern can be formed on the exposed electrode with high precision, and as a result,
Connection with external electrodes and external terminals has become better.

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

[Brief explanation of the drawing]

FIGS. 1 and 2 are external views showing the front and back end faces of an electrostrictive material laminate provided with temporary external electrodes 12 and 14 for the purpose of applying electrophoresis. Numbers 13 and 16 in the figure are internal electrode exposed parts. Third
FIG. 4 is an external view showing an electrostrictive material laminate in which glass powder is adhered to a part of the internal electrode exposed portion and the surrounding ceramic. Numbers 11 and 15 in the figure indicate 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. Number 17 in the figure is an external electrode,
19 and 20 indicate external connection terminals, respectively. 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. In the figure, numeral 31 indicates a counter electrode plate, and 32 indicates a conductive 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.

Claims (1)

[Claims] 1. In a suspension containing charged glass powder, the glass powder is selectively attached to 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 around it. In the method for manufacturing an electrostrictive effect element, the potential of the internal electrode to which no glass powder is attached is set to the same potential as that of the counter electrode or a potential close to it in the step. .