JPS6086882A - Manufacture of electrostrictive-effect element - Google Patents

Abstract

PURPOSE:To obtain the insulating coated film of a fine pattern by a method wherein electrified glass powder is accumulated on the surface of a laminated body, which has been made of electrostrictive material and placed in a suspension, and unnecessary glass powder of the glass powder is removed by applying an electric field in between internal electrodes constituting the laminated body and an opposed electrode plate installed in the suspension. CONSTITUTION:A laminated body 21 constituted by laminating alternately internal electrodes and electrostrictive material is placed in an electrified glass powder-containing suspension 26. The internal electrodes are made to expose at the end surfaces of the laminated body 21. A temporary external electrode 22 and a temporary external electrode 23 are provided on both sides of the laminated body 21, and the temporary external electrodes 22 and 23 are made to connect with the internal electrodes every one layer. The laminated body 21 is left intact in the suspension 26, glass powder 24 is made to be accumulated on the surface of the laminated body 21 and a DC power source 27 is connected to the external electrode 23 and an opposed electrode plate 25. According to such a way, the glass powder 24 in the vicinities of the internal electrodes connected to the electrode 23 is removed. By baking the laminated body obtained in such a way, the insulating coated film of a fine pattern not only can be formed, but also the layer thickness thereof can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an electrostrictive element using longitudinal effect.

In the structure of an electrostrictive element that utilizes the longitudinal effect, it is necessary to have internal electrodes that are the same size as the entire cross section of the element in order to prevent stress concentration when strain occurs by generating an electric field throughout the electrostrictive material. be. In order to generate a high electric field with a very low voltage and obtain a large strain, the distance between the internal electrodes should be set to 100 mm.
It is necessary to rub by a micron. For the above two reasons, it is very difficult to electrically connect an electrostrictive element having poles within the same area as the cross section of the element.

Therefore, the present inventors first developed an electrical connection method characterized by forming an insulator every other layer on the internal electrode layer exposed on the end face of the electrostrictive material laminate and the ceramic in its vicinity by electrophoresis. proposed.

FIG. 1 is an external view of an electrostrictive effect element connected by this method. An insulator 7 is formed every other layer by electrophoresis on the internal electrode layer exposed on the end face and the ceramic layer in the vicinity thereof. On the back end surface, there is an internal space that is shifted by one layer.
F! An insulator 8 is also formed on the top. A band-shaped external electrode 11 is formed by crossing the pole 4 through this insulator and the exposed hollow inside. By similarly forming external electrodes for the internal electrodes 3 on the back side, a large number of internal electrodes are connected to the positive side terminal 13 or the negative side terminal 12 at every other layer. By applying a DC voltage between these external terminals, a uniform electric field is generated over the entire area of the electrostrictive material 2 except for the protective film portion 1, and the element is expanded in parallel to the stacking direction. Since there is no stress concentration, the element will not be destroyed even if tη repeated voltages are applied, and since the distance between internal electrodes is short, it can be driven with a low voltage of 100 V or less.

The method for manufacturing this element will be explained in the previous year.

First, an internal VT pole 3.4 and an electrostrictive material 1 as shown in FIG.
．． A laminate in which 2 and 2 are alternately stacked is manufactured by applying manufacturing technology for multilayer ceramic capacitors.

A large number of internal electrodes 3.4 are exposed on the front and back end surfaces, and two temporary external electrodes 5.6 are formed at 911.
They are connected alternately every other layer. When this laminate and a metal plate for a counter electrode are placed in a suspension and a DC voltage is applied from the counter electrode plate toward the temporary external electrode 5, the positively charged glass powder in the suspension is is deposited on the internal electrode 3 and the electrostrictive material in its vicinity by electrophoresis. FIG. 3 is an external view of a laminate with glass powder adhered to the front end face. In the figure, numeral 1 indicates an electrostrictive material that functions as a protective film, and numeral 2 indicates an electrostrictive material in a portion where an electric field is generated to cause distortion. The inner electrodes 41 are shown exposed, and the inner electrodes between them are covered with glass powder 7.

After the glass powder is baked and fixed, the glass powder is applied to the back end face in the same manner and fixed by baking.

The laminated body formed with this insulator is cut at the position shown by the broken line in FIG.
When the outer electrode 11 is formed in half, the electrostrictive effect element shown in FIG. 1f is obtained.

The problem with this method is that the band-shaped insulator formed by adhesion tends to be cut or constricted. The reason is thought to be that convection within the suspension generates locally weak electric field areas, and no adhesion occurs in those areas.

If an external electrode is formed on top of it after firing and fixing, it will cause a short circuit at the broken part, and the dielectric strength will drop significantly at the constricted part, making it impractical.The purpose of the present invention is to solve this problem. A laminate of an electrostrictive material and an internal electrode as shown in the figure is immersed in a suspension containing charged glass powder, and the glass powder is deposited on the entire exposed end surface of the internal electrode. Next, a counter electrode plate is installed in the same suspension, and the temporary outside is placed opposite the pole 6! Apply direct current and pressure between the electrode plate. The internal electrode 4 connected to the temporary external electrode 6 and the glass powder deposited near it are positively charged even after deposition, so
It is removed from the surface of the laminate by electrostatic force in the direction of the DC electric field. The pattern shape of the obtained insulator is exactly the same as that of the usual electrophoresis method, that is, when a DC voltage is applied from the counter electrode plate toward the temporary external electrode 5. However, the glass powder layer formed in advance by deposition is perfect with no defects, and the glass powder layer on the ceramic on the internal electrode 3 and its vicinity is destroyed by applying voltage after deposition. Not at all.

The feature of the present invention is that after depositing on the entire surface, only unnecessary portions are removed. By this method, you will not be confused
Although more glass powder may remain in certain areas, the glass powder is completely adhered to the areas that should be insulated.
By firing and fixing, a good band-shaped insulating film with no cuts or constrictions is formed.

The present invention will be explained in detail below according to Examples.

First, a large number of internal electrodes and a set of temporary external electrodes 11 have a structure as shown in FIG. An electrostrictive material 2 having a pole is made by the following method.

Magnesium lead niobate (Pb(fVigl/3Nb2
/3) A slurry was prepared by adding an amount of an organic binder to an electrostrictive material pre-fired powder containing lead titanate (PbTiO) and lead titanate (PbTiO, ) 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 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. 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, temporary external electrodes were applied and baked, and the sides were cut to obtain a laminate with exposed internal electrodes as shown in Figure 2. . Electrophoresis is applied to the electrostrictive material laminate thus obtained. In FIG. 2, reference numeral 1 indicates the electrostrictive material of the protective film portion, and reference numeral 2 indicates the electrostrictive material that causes strain. The inner electrodes 3.4 are connected to the temporary outer electrodes 5 and 6 respectively, and the other inner electrodes are connected alternately to the two temporary outer electrodes on every other layer.

Next, a suspension containing glass powder as deposits is prepared by the following method. 30g borosilicate crystallized glass powder
, 290 ml of ethanol! , 10 m/5% iodine ethanol solution are mixed in a high speed homogenizer. Iodine acts as an electrolyte, and the glass powder is positively charged. After applying ultraback waves for 30 minutes, the suspension was allowed to stand for 30 minutes to remove the precipitate, and the remaining suspension was used.

After covering one end face of the electrostrictive material laminate with an exposed internal electrode with an adhesive tape to prevent it from getting wet with the suspension, submerge it in the suspension with the end face to be attached facing upward; 1
Leave for 5 minutes to deposit glass powder all over the end surface. The thickness of the deposited glass powder can be increased by leaving it for a longer period of time.The centrifugation method can forcefully accelerate the sedimentation rate and increase the density of the deposited layer.

Next, the counter electrode plate is submerged in the suspension, and the upper part of the laminate is
Install it at the cIrL position. Connect a temporary external electrode to the positive terminal of the DC power supply and face the negative terminal! Connect the electrode plates and apply 20V for 200 seconds. In this case, ethyl alcohol may be used instead of the suspension.

FIG. 5 is a conceptual diagram showing the installation method. In the figure, number 21 indicates an electrostrictive material laminate having internal electrodes, 22 indicates a temporary external electrode that collects internal electrodes that should be insulated, and 23 indicates a temporary external electrode that collects internal electrodes that should be exposed = 21
1 is glass powder deposited on the end surface of the carcass. 25 is on the opposite side! Electrode plate, 26 is the suspension or ethyl alcohol, 2
7 indicates the DC power supply, and the name indicates the container.

After applying a voltage, the laminate is pulled up from the suspension or ethanol, dried, and baked at 710° C. in an air atmosphere to fix it.

Form a pattern on the opposite end face in the same way.
After that, it is cut at the position of the broken line as shown in Fig. 4, and a band-shaped outer ffts electrode is formed on the two surfaces on which the insulator is formed.As shown in Fig. 1, the inner pole is equal to the cross section of the element. The electrostrictive element can be electrically connected.

The problem with the present invention is that it is not a scale that can form a thin insulation pattern with high reliability, and the conventional control is not capable of forming thin insulation patterns with high reliability. l!
It is possible to achieve the layer thickness of the insulator, which was lI@, by a simple method of controlling the standing time in the suspension, and this manufacturing method is suitable for mass production.

[Brief explanation of the drawing]

M1 diagram is an internal lt! electrically connected using electrophoresis method. FIG. 7 is an external view showing an electrostrictive effect element in which LIJ7A is equal to the cross-sectional area of the element. In the figure, number 1 is the electrostrictive material ceramic of the protective film part, 2 is the electrostrictive material ceramic of the part that causes strain, 3.4 is the internal electrode, 7.8 is the insulating coating that covers them, and 11 is the internal 'a electrode. External electric currents 4M are shown which are connected to each other every other layer. 12 and 13 indicate negative and positive external terminals. FIG. 2 is an external view of an electrostrictive material laminate to which electrophoresis is applied. In the figure, number 1 is the electrostrictive material laminate in the protective film portion, 2 is the electrostrictive material laminate in the portion where strain is generated, 3.4 is the internal electrode exposed on the end surface, and 5.6 is the interconnection between these. The temporary outer s-electrodes are shown respectively. FIG. 3 is an external view of an electrostrictive material laminate in which glass powder is formed on the exposed portion of the internal electrode on the end face and the surrounding ceramic. In the figure, number 1 is the electrostrictive material ceramic of the protective film part, 2 is the electrostrictive material ceramic of the part where strain is generated, 7 is the attached glass powder, and 5.6 is the temporary exterior that interconnects the internal electrodes every other layer. Electrodes 4 indicate exposed internal electrodes, respectively. FIG. 4 is an external view showing the cutting position (dotted line portion) of the electrostrictive material laminate on which the insulating coating is formed. In the figure, number 9 indicates an unusable portion at both ends, and 1θ indicates a portion that functions as an electrostrictive element by forming an external electrode. FIG. 5 is a schematic diagram showing a method of connecting an electrophoresis device according to the method of the present invention. Number 21 in the figure is an electrostrictive material laminate, n
indicates a temporary outer electrode that is a group of inner electrodes to which glass powder should be attached, and a temporary outer electrode that is a group of inner electrodes to which no glass powder should be attached. U is the deposited glass powder, 2
5 is a counter electrode plate, 26 is a suspension containing charged glass powder or ethanol, 27 is a DC power source, and the path is a container. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] An electrostrictive material laminate in which electrostrictive materials and internal electrodes are alternately laminated is produced, and glass powder is attached onto a portion of the internal electrodes exposed on the end surface I of the laminate and the electrostrictive material in the vicinity thereof. In a method for manufacturing an electrostrictive effect element having a step, the laminate is placed in a suspension containing charged glass powder, the glass powder is deposited on the entire surface of the end face by sedimentation in advance, and then the glass powder is attached. Inside that won't let you! The method is characterized in that by applying an electric field between the electrode and a metal plate for a counter electrode placed in the suspension, only the glass powder deposited on the internal electrode, which does not allow the glass powder to adhere, is removed by electrostatic force. A method for manufacturing an electrostrictive element.