JPH04145674A - Electrostrictive effect element and production of the same - Google Patents

Abstract

PURPOSE:To realize high quality by providing a chamfered areas to the periphery of both end faces in the displacing direction of an element. CONSTITUTION:Generation of crack or cutting with an external impact is made difficult by executing the chamfering in the predetermined inclination to both end faces 5a, 5b in the displacing direction and respective four sides of an element. An element can precisely control a fine mechanical displacement as a piezoelectric actuator. Mass-production is possible by previously forming the chamfered areas like a V-shaped groove and cutting the groove at the center in the producing process.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrostrictive effect element and a manufacturing method thereof, and in particular,
This invention relates to improving the end face shape of an electrostrictive element.

[Conventional technology]

An electrostrictive effect element (hereinafter referred to as an element) has an electrostrictive effect that
It converts electrical energy into mechanical energy to generate minute mechanical displacements, and is currently used as a piezoelectric actuator element in mass flow controllers in semiconductor integrated circuit manufacturing equipment, X-Y tables in exposure equipment,
Alternatively, it is used in fields where it is necessary to precisely control the amount of movement of minute positions, such as plastic injection molding machines.

This element has a so-called laminated structure in which thin layers of electrostrictive material and internal electrodes are alternately laminated so that a large displacement can be obtained with a low voltage. things are widely used.

FIG. 4 shows the structure of a conventional element.

In the conventional element shown in FIG. 4, ceramic layers 1 exhibiting an electrostrictive effect and internal electrodes 2 are alternately laminated, and internal Insulators 3 are provided on every other layer so as to cover the exposed portions of the electrodes 2 and the portions of the ceramic layer 1 in the vicinity thereof.

In such a structure, the internal electrodes 2 are connected to the same external electrode 4 every other layer, and adjacent internal electrodes serve as opposing electrodes with the ceramic layer 1 in between, so that a voltage cannot be applied to the external electrode 4 from the outside. Then, the ceramic layer 1 exhibits an electrostrictive effect, and mechanical displacement occurs in the direction indicated by the arrow in FIG.

Elements with the above-mentioned structure are manufactured by cutting out a large laminate and finishing it with the desired shape and dimensions during the manufacturing process, as will be described later. However, in conventional elements, the fourth
As shown in the figure, since the four sides of both end faces 5a and 5b in the displacement direction are not chamfered in the cut-out state, the angles formed by the side faces and both end faces 5a and 5b of the element are acute angles. be.

The manufacturing process of a conventional element having the above structure will be described below.

To fabricate the conventional element shown in Figure 4, first, a ceramic calcined powder using lead titanate or the like as an electrostrictive material is prepared, and this is dispersed in an organic solvent together with an organic binder and a plasticizer. to create a slurry.

A green sheet of a predetermined size is produced from this slurry by slip casting using a doctor blade.

Next, as shown in FIG. 5(a), a mixed paste made by making a paste of a mixed powder of silver powder and palladium powder together with a vehicle is applied to one side of the green sheet 6 using a printing screen method. The internal electrodes 2 are formed by drying.

Next, the green sheet 6 on which the internal electrode 2 was formed was placed in one
Rotate every other sheet 180°, stack the specified number of sheets,
The green sheet was pressed from top to bottom with a heat press, heated to a temperature of 500°C to decompose and remove the organic binder and plasticizer contained in the green sheet, and then fired at 1120°C to form a green sheet as shown in Figure 5(b). A laminate 7 is obtained.

Next, as shown in FIG. 5(c), the fired laminate 7 is cut into a block shape using a cutting machine using a metal wire 8 such as piano wire. .

At this time, the end surfaces of the internal electrodes are exposed on the left and right surfaces of the block at every - layer, so in the next step, silver paste is applied to the end surfaces of the block 9, as shown in FIG. 5(d). After forming the pair of temporary electrodes 10a and 10b, the internal electrodes 2 are alternately connected to the left and right temporary electrodes 10a and 10b every other layer.

Next, as shown in 5(e), a masking material 11 such as Teflon tape is pasted on one cut surface of the block 9, and temporary electrodes 1 are formed on the left and right surfaces of the block 9.
A voltage is applied to 0a and 10b, and glass powder is electrodeposited every other layer on the internal electrodes exposed on the cut surface of the block 9 by electrophoresis, and is fired to form the insulator 3.

Next, apply masking material to the side opposite to the previous process,
A voltage opposite to that in the previous step is applied to the temporary electrode to form an insulator at a position different from that of the insulator formed in the previous step.

Next, as shown in FIG. 5(f), external electrodes 4 such as silver base are formed on the alternately exposed internal electrodes 2,
After connecting each internal electrode and external electrode, as shown in FIG. 5(g), the element shown in FIG. 4 is obtained by cutting into chips using a cutting machine using a wire 8 such as a piano wire. It will be done.

[Problem to be solved by the invention]

In the conventional element described above, each side of both end faces in the displacement direction is not chamfered, and the angles formed between both end faces of the element and the side surfaces are acute angles, so each side of both end faces is extremely sensitive to external force. brittle.

For this reason, even a slight impact can cause cracks or chips on the end face of the element that serves as a reference for displacement, making it difficult to precisely control minute displacements on the micron order when this element is used as a piezoelectric actuator element. I become unable to do so.

In addition, the mechanical strength of the element is reduced and the quality is degraded.

On the other hand, methods for chamfering each edge include, for example, the sandblasting method in which fine particles such as alumina are hit at high speed on the area to be chamfered, and
There is a method of grinding one side or all four sides at the same time using a grinder.

However, the sandblasting method may damage parts other than the part to be chamfered, which may impair the performance and quality of the element as described above, and the dimensional accuracy of chamfering is poor.

On the other hand, the method of grinding with a grinder requires complicated equipment.

In either method, the elements are cut into chips and then chamfered, so they are not suitable for mass production and have the disadvantage of causing a decline in performance and quality.

[Means to solve the problem]

The electrostrictive element according to claim 1 is a laminated electrostrictive element in which layers of electrostrictive material and layers of internal electrodes are alternately laminated, and the electrostrictive element has the following features: It is characterized in that a chamfered portion is provided at the periphery of the two end faces.

The method for manufacturing an electrostrictive element according to claim 2 further includes a step of forming a laminate in which layers of a material exhibiting an electrostrictive effect and layers of internal electrodes are alternately laminated and integrated; In the method for manufacturing a multilayer electrostrictive element, the method includes the steps of cutting the block to form a block, and cutting the block to form a chip, in which the block forming step is performed in a direction perpendicular to the cutting direction of the laminate. A groove is prepared in advance at the cutting position of the pair of surfaces, and this V
The laminated body is cut at the groove position, and in the chip forming step, a V groove is provided in advance at the cutting position of a pair of surfaces perpendicular to the cutting direction of the block, and the block is cut at the position of the V groove. Characterized by cutting.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention.

In this example, a ceramic made of lead zirconate titanate having a composite herovskite structure is used as the electrostrictive material, and a silver-palladium alloy is used as the internal electrode. The structure of the element is shown in FIG. Although it has a similar structure to a conventional element, each of the four sides of both end faces 5a and 5b in the displacement direction of the element is chamfered with an inclination of about 45 degrees.

The device of this example was fabricated by a manufacturing process similar to that of the conventional device described above, but in this case, when cutting out the fired laminate to cut out the prongs, as shown in Fig. 2 (a). ), first, using a circumferential blade cutter such as a dicing saw, the arms 12 are provided at cutting positions on the upper and lower surfaces of the laminate 7.

In this example, a V-groove having a width of 2 m11 and a depth of lam was provided.

Next, as shown in FIG. 2(b), the block was cut at the position of the V-groove 12 using a cutting machine using a wire 8, as in the conventional manufacturing method.

Furthermore, when the manufacturing process progresses and the block on which the external electrodes are formed is cut to cut out the chips, as shown in Figure 3(a), first, a peripheral blade cutting machine such as a dicing saw is used to cut out the chips.・Is there a V at the cutting position on the upper and lower surfaces of the link 9?
1112, as shown in Figure 3(b),
At this V edge position, a cutter was used to cut out chips.

In the device according to Example 8, which was manufactured by the manufacturing process described above, as shown in FIG. , there is less chance of black staining or chipping due to external impact.

〔Effect of the invention〕

As explained above, according to the invention set forth in claim 1, chamfers are provided on the peripheral edges of both end faces in the displacement direction of the electrostrictive effect element, so that cracks and chips may occur on the surface serving as a reference for displacement. When used as a piezoelectric actuator, it is possible to obtain a high-quality electrostrictive effect element that can precisely control minute mechanical transformations.

In addition, the invention as claimed in claim 2 adopts a method of processing the chamfered parts at once when the chamfers are formed on both end faces in the displacement direction of the electrostrictive effect element when the shape is large, such as a laminate or a block. Therefore, it has the advantage of being extremely easy to mass-produce.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of an electrostrictive effect element according to an embodiment of the present invention, FIGS. 2(a) and 2(b) are diagrams for explaining a block forming process in an embodiment of the present invention, Third
Figures (a> and (b) are diagrams for explaining the chip forming process of the embodiment of the present invention, Figure 4 is a perspective view showing the structure of a conventional electrostrictive effect element, and Figure 5 (a) to (g) are diagrams for explaining the manufacturing process of a conventional element. 1... Ceramic layer, 2... Internal electrode, 3... Insulator, 4... External electrode, 5a , 5b... end face, 6.
...Green sheet, 7... Laminate, 8... Wire 9... Block, 10a, 10b... Temporary electrode,
11...Masking material, 12...■渭.

Claims (2)

[Claims] 1. In a laminated electrostrictive element formed by alternately laminating layers of electrostrictive material and layers of internal electrodes, chamfers are provided at the peripheral portions of two end faces perpendicular to the displacement direction of the laminated electrostrictive element. A multilayer electrostrictive effect element characterized by: 2. a step of forming an integrated laminate in which layers of a material exhibiting an electrostrictive effect and layers of internal electrodes are alternately laminated; a step of cutting the laminate to form a block; and a step of cutting the block. In the method for manufacturing a laminated electrostrictive effect element, the block forming step includes forming a V-groove in advance at a cutting position on a pair of surfaces perpendicular to the cutting direction of the laminated body. The laminated body is cut at the position of the V-groove, and in the chip forming step, a V-groove is previously provided at the cutting position of a pair of surfaces perpendicular to the cutting direction of the block, and the block is cut at the position of the V-groove. A method for manufacturing a multilayer electrostrictive element, characterized in that: