JP2001178162A - Piezoelectric actuator and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a manufacturing method, in which a very small high- performance piezoelectric actuator of stable quality can be manufactured with high efficiency. SOLUTION: This piezoelectric actuator is manufactured of a composite material 20, in which a piezoelectric element material 11a and a support material 12a are laminated. Electrodes 13, 14 are installed at the piezoelectric element material 11a. Masks 21, 22 in prescribed patterns are formed on the piezoelectric element material 11a and the support material 12a. The support material 12a is composed of a brittle and elastic material which is composed of a ceramic, a glass, Si or the like. In a blasting process, solid fine particles 30, whose hardness is equal to or more than that of the support material 12a, are blasted into the composite material 20, and parts other than the masks 21, 12 are crushed so as to be removed. Thereby, the piezoelectric actuator 10 can be obtained, which has the piezoelectric elements 11 and supports in desired patterns according to the masks 21, 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric actuator suitable for a micro device or the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art A piezoelectric actuator for a microdevice using a vibrator composed of a piezoelectric element and a support transmits vibration generated when an alternating current is applied to the piezoelectric element to a movable member such as a rotor. Thus, the movable member is rotated or linearly reciprocated. The piezoelectric element is made of a piezoelectric material such as lead zirconate titanate (PZT). The support is made of an elastic material such as ceramics.

In order to manufacture such a piezoelectric actuator, for example, a support is formed into a desired shape by machining, wet etching, or the like, and a piezoelectric element is formed by processing a material plate using a dicing machine. Were assembled and laminated under a microscope.

[0004] As a conventional manufacturing method other than the above,
A slurry containing fine particles of the piezoelectric element, a solvent, an organic component, and the like is printed on the surface of the support in a predetermined pattern by screen printing or the like, and the fine particles of the piezoelectric element are heated and sintered at a high temperature to obtain a piezoelectric element having a predetermined pattern. Is also available.

[0005]

SUMMARY OF THE INVENTION Among the above conventional methods,
The former manufactures the piezoelectric element and the support separately, and then
Since it is necessary to assemble the individual piezoelectric actuators with high accuracy, not only is it troublesome to manufacture a small piezoelectric actuator, but also the performance of each completed piezoelectric actuator tends to vary. Further, in the dicing process, since the shape of the portion to be processed is limited to a straight line, a piezoelectric element having a curved surface cannot be formed.

[0006] Among the above conventional methods, the latter sinters the slurry at a high temperature, so that pores may be generated inside the piezoelectric element when the solvent or the organic component is removed. When holes are formed in the piezoelectric element, there is a problem that the mechanical strength of the piezoelectric element itself decreases and the piezoelectric characteristics also decrease. There is also a problem that the support is deformed due to the contraction of the piezoelectric element during sintering. When the support is deformed, the characteristics of the piezoelectric actuator become non-uniform, and it may not be possible to mount the piezoelectric actuator on other parts.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a piezoelectric actuator which can solve the above-mentioned problems and has high performance and stable characteristics, and a manufacturing method capable of efficiently manufacturing this actuator.

[0008]

According to another aspect of the present invention, there is provided a piezoelectric actuator, comprising: a piezoelectric element provided with electrodes and formed in a predetermined pattern by a blast process for hitting solid fine particles; And a support made of a material having elasticity and brittleness formed in a predetermined pattern by the blast treatment. The support is made of, for example, an elastic member such as ceramics, glass, or Si.

According to the method of manufacturing a piezoelectric actuator of the present invention, a composite material is obtained by laminating and fixing a brittle support material on a piezoelectric element material provided with electrodes, and a predetermined pattern is formed on the surface of the composite material. Forming a mask, a blast step of crushing and removing portions other than the mask by hitting solid fine particles on the surface of the composite material on which the mask is formed, and a step of removing the mask ing. As the mask, a photosensitive resist mask or a metal mask is used. As the solid fine particles, fine particles of ceramic, glass, Si or the like having a hardness equal to or higher than that of the piezoelectric element material are used.

[0010] The blasting process referred to in the present invention means that a large number of solid fine particles are mixed into a gas such as air or an accelerated fluid such as a liquid and struck on a processing object (piezoelectric element material or support material). This is a process of crushing and removing a portion of the processing object that is not covered with the mask.
It is desired that the hardness of the solid fine particles is equal to or higher than the hardness of the piezoelectric element and the support. These processing objects need to have a certain degree of brittleness, but thin-film electrodes and the like can also be removed by this blasting.

In the present invention, a first mask is formed on the piezoelectric element material side of the composite material, and a second mask having a different pattern from the first mask is formed on the composite material side of the support material. The first blasting process may be performed from the first mask side, and the second blasting process may be performed from the second mask side. In this case, the blast conditions may be changed between the first blast processing and the second blast processing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A piezoelectric actuator 10 according to an embodiment of the present invention and a process for manufacturing the piezoelectric actuator 10 will be described below with reference to the accompanying drawings. An example of the piezoelectric actuator 10 schematically shown in FIGS. 9 and 10 includes a plurality of piezoelectric elements 11 and a comb-shaped support 12 on which the piezoelectric elements 11 are stacked. A first electrode 13 is provided on one surface of the piezoelectric element 11. The second electrode 14 is provided on the other surface of the piezoelectric element 11, that is, between the piezoelectric element 11 and the support 12. These electrodes 13 and 14 are metal thin films (an example of a thickness of several μm to several tens μm) formed on both surfaces of the piezoelectric element 11 by, for example, sputtering.

The piezoelectric element 11 is made of a piezoelectric material such as lead zirconate titanate (PZT).
When an alternating current is applied in between, vibrations of expansion and contraction in a specific direction are excited by a well-known piezoelectric action. Based on the vibration, a movable component (not shown) such as a rotor is driven in a predetermined direction via a support 12 functioning as an elastic body. That is, the piezoelectric element 11 and the support 12 can function as a vibrator of a micro device.

The material 12a of the support 12 (shown in FIG. 1)
Is an alumina plate having a thickness of 50 μm. The support 12 may be made of ceramics such as zirconia, or an inorganic material such as glass or Si. In short, the property required for the support 12 is that it has high mechanical strength, and has elasticity that can bend in a specific direction such as the thickness direction by vibration excited by the piezoelectric element 11, and can be crushed by blasting. It is a point that has a great brittleness.

Next, a method of manufacturing the piezoelectric actuator 10 will be described. As shown in FIG. 1, A
A plate-like piezoelectric element material on which electrodes 13 and 14 made of u or the like are formed (for example, a PZT bulk having a thickness of 80 μm) 11a
Then, a plate-like alumina support material 12a having a thickness of, for example, 50 μm is prepared. Note that zirconia or glass may be used for the support material 12a instead of alumina. For example, an epoxy-based adhesive is applied between the piezoelectric element material 11a and the support material 12a, and the two are fixed by curing the adhesive as shown in FIG. 2 to obtain the composite material 20.

As shown in FIG. 3, a first mask 21 having a predetermined pattern is formed on the surface of the piezoelectric element material 11a.
As shown in FIG. 4, a second mask 2 having a pattern different from that of the first mask 21 is formed on the surface of the support material 12a.
Form 2 One example of the masks 21 and 22 is a resin-based film in which a photosensitive resist is patterned by photolithography or the like. Note that a metal mask (metal mask) may be formed by etching or electroforming.

These masks 21 and 22 are, for example, shown in FIG.
As a representative example of one of the masks 22, a predetermined number of the masks 22 are formed on a composite material 20 having a large area (for example, an area capable of manufacturing several tens or hundreds of piezoelectric actuators 10).

As schematically shown in FIG. 6, in the first blasting process, solid particles 30 of SiC having a particle diameter of, for example, 40 to 80 μm are accelerated from the first mask 21 by air while the nozzles 31 are accelerated. At a subsonic speed toward the composite material 20 at random. The solid fine particles 30 collide with the mask 21 and also collide with a portion not covered by the mask 21.

Here, the portion not covered by the mask 21 is finely crushed by the collision of the solid fine particles 30, and the crushed fragments are blown away by the flow of air and removed. The portion covered by the mask 21 remains as it is. That is, the electrode 13 which is a metal thin film is
The portion not covered by the mask 21 is removed by this blasting. The portion of the brittle piezoelectric element material 11a that is not covered with the mask 21 is also crushed by this blasting.

By the first blasting process, as shown in FIG. 6, the electrode 13 and the piezoelectric element material 11a are removed only at the portion without the mask 21 and the portion corresponding to the mask 21 remains, so that the piezoelectric element of the desired pattern is left. 11 is molded. In addition, the support material 12a that is harder than the piezoelectric element material 11a and hard to crush remains.

FIG. 7 shows the composite material 20 after the blast processing.
Is viewed from the support material 12a side. Since the second mask 22 is formed on the support material 12a, a second blasting process is performed from the second mask 22 side as shown in FIG. Also in this case, solid fine particles 30 of SiC having a particle diameter of, for example, 40 to 80 μm are sprayed onto the composite material 20 from the mask 22 by the nozzle 31 at a subsonic speed.

Since the support material 12a is harder to crush than the piezoelectric element material 11a, in the second blasting process, the processing time is longer than that in the first blasting process, By changing the blasting conditions such as making the harder, the portions not covered by the second mask 22 can be solid fine particles 3.
Remove by 0. In this way, the support material 12a is scraped off only at the portion without the mask 22, and the portion corresponding to the mask 22 remains as shown in FIG. 8, whereby the support 12 having a desired pattern is formed.

Thereafter, the masks 21 and 22 are peeled off from the piezoelectric element 11 and the support 12 with a solvent or the like, and are removed to complete the piezoelectric actuator 10 as shown in FIGS. 9 and 10.

According to the manufacturing method described above, a large number of piezoelectric actuators 10 can be manufactured simultaneously from a single composite material 20 as shown in FIG. 5 under the same manufacturing conditions. In addition, not only can a large number of piezoelectric actuators 10 be efficiently manufactured, but also it is possible to avoid variations in the characteristics of the individual piezoelectric actuators 10 manufactured simultaneously. Therefore, when a plurality of piezoelectric actuators 10 are mounted on the same device, the piezoelectric actuators 10 can exhibit the same characteristics. Therefore, devices using these piezoelectric actuators 10 can stably exhibit desired performance.

In carrying out the present invention, the constituent elements of the present invention, such as the material of the piezoelectric element and the support, the form of the composite material, the electrodes, the solid fine particles for blasting, and the form of the mask, are used. It goes without saying that various changes can be made without departing from the scope of the invention.

[0026]

According to the first aspect of the present invention, it is possible to provide a piezoelectric actuator having a piezoelectric element and a support that can be formed into a desired shape by blasting. According to the manufacturing method described in claim 2, the piezoelectric element and the support constituting the piezoelectric actuator can be efficiently formed without using mechanical processing such as dicing.
Curved shapes can be formed without any problems.

According to the third aspect of the present invention, it is not necessary to assemble one piezoelectric element and a support body each having a desired shape as in the prior art, and a plurality of piezoelectric actuators can be manufactured simultaneously under the same manufacturing conditions. As a result, a piezoelectric actuator having uniform characteristics can be obtained efficiently at the same time,
The performance of the device using the plurality of piezoelectric actuators can be made more stable.

According to the fourth aspect of the present invention, the piezoelectric element and the support having a desired pattern can be easily and efficiently processed by hitting solid fine particles on the piezoelectric element material and the support material. According to the fifth aspect of the present invention, the piezoelectric element and the support having different patterns from each other can be obtained by the blast processing performed from the piezoelectric element side and the blast processing performed from the support side.

[Brief description of the drawings]

FIG. 1 is a perspective view of a piezoelectric element material and a support material used for a piezoelectric actuator according to an embodiment of the present invention.

FIG. 2 is a perspective view of a composite material in which a piezoelectric element material and a support material are laminated.

FIG. 3 is a perspective view of a composite material on which a first mask is formed, as viewed from a piezoelectric element material side.

FIG. 4 is a perspective view of a composite material on which a second mask is formed, as viewed from a support material side.

FIG. 5 is a plan view showing a part of a composite material on which a number of masks are formed.

FIG. 6 is a perspective view conceptually showing how a first blasting process is performed on the composite material from the piezoelectric element side.

FIG. 7 shows the composite material subjected to the first blast treatment,
FIG. 2 is a perspective view as viewed from a support side.

FIG. 8 is a perspective view conceptually showing how a second blasting process is performed on the composite material from the support side.

FIG. 9 shows a piezoelectric actuator from which a mask has been removed.
FIG. 3 is a perspective view as viewed from a piezoelectric element side.

FIG. 10 is a perspective view of the piezoelectric actuator shown in FIG. 9 as viewed from a support.

[Explanation of symbols]

 Reference Signs List 10 piezoelectric actuator 11 piezoelectric element 11a piezoelectric element material 12 support 12a support material 13, 14 electrode 20 composite material 21 first mask 22 second mask 30 solid fine particles

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor, Itaru Kudo 3-10-10, Fukuura, Kanazawa-ku, Yokohama-shi, Kanagawa Prefecture Within Japan-launched corporation (72) Inventor Masahiro Ogusu 3- 10-10, Fukuura, Kanazawa-ku, Yokohama-shi, Kanagawa, Japan F term in reference company (reference) 5H680 AA00 DD23 DD39 EE10 FF08 FF11 FF17 GG02 GG20 GG42

Claims (5)

[Claims] 1. A piezoelectric element provided with an electrode and formed in a predetermined pattern by blast processing for hitting solid fine particles, and having elasticity and brittleness laminated on the piezoelectric element and formed in a predetermined pattern by the blast processing. A piezoelectric actuator, comprising: a support made of a material; 2. A step of obtaining a composite material by laminating and fixing a brittle support material on a piezoelectric element material provided with electrodes, and a step of forming a mask of a predetermined pattern on the surface of the composite material. A blast step of crushing and removing portions other than the mask by hitting solid fine particles on a surface of the composite material on which the mask is formed; and a step of removing the mask. A method for manufacturing a piezoelectric actuator. 3. A plurality of piezoelectric actuators having the same shape are simultaneously formed by forming a plurality of masks having the same pattern on the surface of the composite material and performing the blasting step. A manufacturing method of the piezoelectric actuator according to the above. 4. The mask is a photosensitive resist mask or a metal mask patterned on the composite material, the support material is a material selected from ceramics, glass, and Si, and 3. The method for manufacturing a piezoelectric actuator according to claim 2, wherein a material selected from ceramics, glass, and Si having a hardness equal to or higher than that of the piezoelectric element material and the support material is used. 5. A first mask is formed on the piezoelectric element material side of the composite material, and a second mask having a pattern different from the first mask is formed on the composite material side of the support material. 3. The method according to claim 2, wherein a first blast process is performed from the first mask side, and a second blast process is performed from the second mask side.