JPH0549270A - Piezoelectric/electrostrictive actuator - Google Patents

Abstract

PURPOSE:To provide a highly reliable and strong piezoelectric/electrostrictive actuator which can produce a large displacement and a high force at high response with relatively low driving voltage and which can be subjected to high integration and suitably employed in an ink jet print head. CONSTITUTION:In a piezoelectric/electrostrictive actuator comprising a ceramic substrate and a piezoelectric/electrostrictive driving section, a recess of predetermined size is made in the ceramic substrate 22 in order to form a thin part 22a and piezoelectric/electrostrictive driving sections 26, 28, 30 are formed on the thin part 22a of the ceramic substrate 22.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a piezoelectric / electrostrictive actuator, in particular, a unimorph type or a bimorph type, which is mainly used for an inkjet printhead, a microphone, a sounding body (speaker, etc.), various vibrators and oscillators, etc. The present invention relates to a piezoelectric / electrostrictive actuator of a type that generates displacement. The actuator referred to here means an element that converts electrical energy into mechanical energy, that is, mechanical displacement or stress or vibration.

[0002]

BACKGROUND ART In recent years, in fields such as optics and precision processing,
A displacement control element that adjusts the optical path length and position on the order of submicrons has been desired, and in response to this, it occurs when an electric field is applied to a piezoelectric / electrostrictive material such as a ferroelectric substance. The development of a piezoelectric / electrostrictive actuator, which is an element that utilizes a displacement based on an inverse piezoelectric effect or an electrostrictive effect, is under way.

By the way, in the ink jet print head and the like, as such a piezoelectric / electrostrictive actuator structure, a conventionally known unimorph type or bimorph type is preferably adopted. And there,
To improve the printing quality and printing speed of printers using such actuators, in order to meet such demands, in order to meet the demands for miniaturization and high density of piezoelectric / electrostrictive actuators, low voltage drive, and high speed response. Is being developed.

Further, in these unimorph type and bimorph type piezoelectric / electrostrictive actuators, it is important to reduce the thickness of the substrate to be the vibration plate in order to obtain large bending displacement and generated force. When the thickness of the substrate is reduced, there is a drawback that the strength is reduced.

[0005]

The present invention has been made in view of such circumstances, and the problem to be solved is to obtain a large displacement with a relatively low driving voltage.
It has high reliability, fast response speed, and large generating force.
In addition, it is possible to achieve high integration, and it is suitable for inkjet print heads, microphones, sounding bodies (speakers, etc.), various vibrators, oscillators, etc.
An object is to provide an electrostrictive actuator.

[0006]

According to the present invention, in order to solve the above problems, a piezoelectric / electrostrictive actuator formed of a ceramic substrate and a piezoelectric / electrostrictive drive unit has a predetermined size on the ceramic substrate. A recess having a size is formed, the bottom of the recess is a thin-walled portion, and the piezoelectric / electrostrictive drive unit is formed on the surface of the thin-walled portion of the ceramic substrate. A piezo-electric / electrostrictive actuator characterized by the above is the gist thereof.

The present invention also relates to a ceramic substrate and a piezoelectric / piezoelectric material.
In a piezoelectric / electrostrictive actuator formed of an electrostrictive drive unit, the ceramic substrate is a first substrate having holes or cutouts of a predetermined size, and a flat second substrate is a green substrate. By stacking in a sheet state and firing, a recess is formed in the void or cutout portion, and
An integrated multi-layer ceramic substrate in which the bottom of the recess is a thin wall portion is formed, and the piezoelectric / electrostrictive drive unit is further formed on the surface of the thin wall portion of the multi-layer ceramic substrate. A piezoelectric / electrostrictive actuator characterized by:

[0008]

In the piezoelectric / electrostrictive actuator according to the present invention as described above, the piezoelectric / electrostrictive drive unit (first electrode and the layered piezoelectric / electrostrictive drive unit formed on the surface of the ceramic substrate and the thin wall portion thereof is provided. A second electrode and a piezoelectric formed between the electrodes
Since it is composed of an electrostrictive layer), a large displacement can be obtained at a relatively low driving voltage, the response speed is fast, and the generation force is large. By using the process, a large number of elements can be easily formed on the same substrate surface, and the piezoelectric / electrostrictive drive unit can be highly integrated.

Also according to the invention such a piezoelectric /
A ceramic substrate having a laminated structure, which is advantageously used as a substrate for forming an electrostrictive drive unit, includes a first substrate having pores or cutouts of a predetermined size and a flat second substrate, and a green substrate. Since the sheets are laminated in a sheet state and are integrated by firing, the portion of the ceramic substrate to be used as the actuator is the first portion corresponding to the holes or the cutout portions of the first substrate. By making the second substrate part, it is possible to thin only the part concerned,
Therefore, without lowering the strength of the actuator substrate,
Further, the adjacent piezoelectric / electrostrictive drive units do not interfere with each other when displaced, and the actuator can be easily downsized and highly integrated.

In particular, in the present invention, a flat plate-shaped second substrate (which functions as a vibrating plate) is attached to a first substrate having holes or cutouts to form an actuator. Since the structure is such that only the necessary parts are thinned and the strength of the actuator substrate as a whole can be maintained, the function and strength of an actuator structure with many piezoelectric / electrostrictive drive parts on one substrate surface can be improved. Is very effective, and moreover, the first substrate and the second substrate are laminated in the state of a ceramic green sheet or a ceramic green tape and are integrated by firing, It has a highly reliable laminated substrate.

In the piezoelectric / electrostrictive actuator according to the present invention, in order to be able to drive at a low voltage and to obtain a large bending displacement / generated force, the thickness is preferably 1
A piezoelectric / electrostrictive drive unit having a thickness of 00 μm or less, preferably 50 μm or less, and a thickness of 50 μm or less, preferably 30
A ceramic laminated substrate having a thin wall portion (second substrate thickness) of not more than μm.

[0012]

Specific Structure / Examples The present invention will be more specifically clarified below with reference to the drawings showing the specific structure of the piezoelectric / electrostrictive actuator according to the present invention.
In addition, in order to facilitate understanding, the same reference numerals are given to those having the same structure or function throughout the drawings.

First, FIGS. 1 and 2 show an example of a ceramic substrate preferably used in the piezoelectric / electrostrictive actuator according to the present invention.

In this figure, the ceramic substrate 2 is
A first substrate 4 having a rectangular hole 6 of a predetermined size;
It is composed of a flat plate-shaped second substrate 8 superposed on one surface thereof, and the first and second substrates 4 and 8 are laminated in a state of a green sheet, integrated, and baked, It has an integrated structure, and thus has a thin wall portion 8a and a peripheral portion reinforced by the first substrate 4. That is, the integrated substrate 2 has a hole 6
In, the recess is formed, and the bottom of the recess is configured as the thin wall portion 8a.

Further, the ceramic substrate 10 shown in FIGS. 3 and 4 uses a different form from the above as the first substrate. Here, the first substrate 12 is made of a piezoelectric material. / Located at each site where the electrostrictive drive is installed,
A plurality of rectangular hole portions 14 are provided in parallel.
Then, such a first substrate 12 is integrally laminated with the second substrate 8 to form a recess of a predetermined size at a portion corresponding to the plurality of holes 14, and The bottom of the recess is configured as the thin wall portion 8a.

Further, in the ceramic substrate 16 shown in FIGS. 5 to 7, as the first substrate 18, a portion corresponding to the portion where the piezoelectric / electrostrictive drive portion is provided is cut off, and the ceramic substrate 16 is cut into a predetermined size. The second substrate 8 having a flat plate shape is integrally laminated and integrated on such a first substrate 18 as described above by using a U-shaped member provided with the portion 20. Has been formed. Thereby, the ceramic substrate 16
In the above, since the thin thickness portion 8a is formed in a portion corresponding to the cutout portion 20 of the first substrate 18, and the bottom portion of the second substrate 8 is reinforced with its rectangular peripheral edge in a U shape. is there. As described above, the first substrate 18 may be in the form of a cutout, in addition to the form of holes, as long as it has an integral structure.

Further, in the ceramic substrate 38 shown in FIGS. 8 to 10, the first substrate 40 having a rectangular shape is
A portion corresponding to a portion where the piezoelectric / electrostrictive drive portion is provided is cut away, and a rectangular hole portion 42 is provided, and
At both ends of the hole 42 in the longitudinal direction (horizontal direction in the drawing), stepped portions 44 cut out from the hole 42 for a predetermined length are provided. This allows the ink jet print head to be used as a flow path for guiding the ink from the ink tank when the ink jet nozzle substrates are joined when applied to the ink jet print head. Then, the flat plate-shaped second substrate 8 is laminated and integrated on the first substrate 40 in the same manner as described above.

With these structures, only the ceramic substrate portion necessary for the actuator can be thinned, and the strength of the entire actuator substrate can be maintained. With such a substrate structure, it is possible to achieve both function and strength as an actuator structure having a large number of piezoelectric / electrostrictive drive units on one substrate surface, and it is a ceramic integrally fired product. Therefore, the laminated substrate has high heat resistance and extremely high reliability.

The present invention is one in which a desired piezoelectric / electrostrictive actuator is formed using a laminated ceramic substrate having the above-mentioned structure, and some specific examples thereof are shown in FIGS. Is shown in.

First, in the piezoelectric / electrostrictive actuator shown in FIG. 11, the ceramic substrate 22 has a thin wall thickness on the surface corresponding to the portion (bottom of the recess) where the hole portion 24 is provided. A first electrode film 26, a film-shaped or sheet-shaped piezoelectric / electrostrictive layer 28 on the portion 22a,
The second electrode film 30 and the second electrode film 30 are sequentially laminated to form a multi-layered integrated structure. The first and second electrode films 26 and 30 are extended from the ends of the piezoelectric / electrostrictive layer 28 to form lead portions 26a and 30a, respectively, and the lead portions 26a and 30a are formed. A voltage is applied to each of the electrode films 26 and 30 through. Therefore, in the piezoelectric / electrostrictive actuator having such a structure, when an electric field is applied to the piezoelectric / electrostrictive layer 28, the lateral effect of the electric field-induced strain causes the ceramic substrate 22 to bend in a direction perpendicular to the plate surface. The displacement or the generating force is exhibited.

Further, FIG. 12 shows that a comb-shaped electrode film 36a composed of a plurality of strip electrodes 32 and electrode connecting portions 34 connecting them is formed on the surface of the thin wall portion 22a of the ceramic substrate 22.
And an electrode film 36b having the same shape as that of the electrode film 36a, and the piezoelectric / electrostrictive layer 28 is formed between the electrode films 36a and 36b so as to be in contact with the electrode films 36a and 36b. In the example shown in FIG. In the piezoelectric / electrostrictive actuator having such a structure, when an electric field is applied to the piezoelectric / electrostrictive layer 28, the longitudinal displacement of the electric field-induced strain causes bending displacement or displacement in a direction perpendicular to the plate surface of the ceramic substrate 22. Is the generative power.

Further, FIG. 13 shows that a plurality of piezoelectric / electrostrictive driving portions each including a first electrode film 26, a piezoelectric / electrostrictive layer 28, and a second electrode film 30 are separately provided on a ceramic substrate 22. This is an example in which it is provided, and realizes a highly integrated structure in which a film actuator is preferably used. The substrate 22 used here is one in which a plurality of holes as shown in FIG. 3 are provided on the bottom surface side of the substrate, and a second substrate portion (corresponding to the holes) ( Each piezoelectric / electrostrictive drive section is disposed in the thin wall thickness section).

Furthermore, FIG. 14 shows a ceramic substrate 22.
A plurality of strip-shaped electrode films 32 on one surface of the thin-walled portion 22a of
Is an example in which the piezoelectric / electrostrictive drive portion is formed in a state where the piezoelectric / electrostrictive layer 28 is embedded in the piezoelectric / electrostrictive layer 28.
The electrode layer 34, the piezoelectric / electrostrictive layer 36, and the electrode layer 34 are sequentially laminated and integrated on the electrostrictive drive portion.

Further, the piezoelectric / electrostrictive actuator shown in FIG.
This is an example in which only the shape of 2a is circular, and the piezoelectric / electrostrictive layer 28 and the strip electrode 32 formed on the surface of the ceramic substrate 22 corresponding to the shape of the thin-walled portion 22a are formed. / The electrostrictive drive unit is also provided in a circular shape.

Further, the actuator shown in FIG. 16 is a bimorph type piezoelectric / electrostrictive device in which piezoelectric / electrostrictive drive parts (26, 28, 30) are provided on both sides of the thin wall portion 22a of the ceramic substrate 22. It is an example of an actuator.

The piezoelectric / electrostrictive actuator according to the present invention is specifically manufactured in the following manner.

First, regarding the ceramic substrate (22) on which the piezoelectric / electrostrictive drive section is formed, the material for forming it has a large mechanical strength, and as will be described later, 1400.
Even if it is an oxide-based ceramic material, it can be heat-treated at about ℃, and if it is an insulator or a dielectric that can be laminated and integrated with the piezoelectric / electrostrictive drive unit without using an adhesive or the like, Oxide-based ceramic materials may be used, but among them, at least aluminum oxide, magnesium oxide, zirconium oxide, aluminum nitride,
A material containing any of silicon nitride as a main component is preferably adopted in order to obtain excellent actuator characteristics such as large displacement and generated force and fast response speed. Particularly, aluminum oxide and / or zirconium oxide is mainly used. Preference is given to using ceramic materials as constituents. Furthermore, among them,
In particular, a material whose main component is zirconium oxide stabilized with at least one compound selected from the group consisting of yttrium oxide, ytterbium oxide, cerium oxide, calcium oxide and magnesium oxide has high mechanical properties even at a thin substrate thickness. Of high mechanical strength, high toughness, low stress during heat treatment with the piezoelectric / electrostrictive material used in the film forming method, and chemical reactivity with the piezoelectric / electrostrictive material. Because of its small size, it is advantageously used as a substrate for actuators. Moreover, in the ceramic substrate made of such a stabilized zirconium oxide material, even in the cavity structure according to the present invention, there is an advantage that a large displacement can be easily taken. The amount of the compound added to stabilize zirconium oxide is 1 mol% to 30 mol% for yttrium oxide and ytterbium oxide, and 6 mol% for cerium oxide.
.About.50 mol%, and in the case of calcium oxide or magnesium oxide, it is preferable to set it to 5 mol% to 40 mol%. Among them, it is particularly desirable to use yttrium oxide as a stabilizer. It is preferable that the amount is at least mol% and at most 6 mol%, more preferably at least 2 mol% and at most 4 mol%. Zirconium oxide to which yttrium oxide is added in such an addition range provides excellent substrate characteristics because its crystal phase is partially stabilized.

Further, such a ceramic substrate advantageously functions as a vibrating plate, as well as a first substrate (4, 12, 18, 40) having holes or cutouts of a predetermined size. It is to be formed by using the flat plate-shaped second substrate (8), but at least the second substrate material contains silicon oxide (SiO, SiO ₂ ) advantageously. The content of the silicon oxide is preferably 0.5% by weight or more and 5% by weight or less, and particularly 1% by weight or more and 3% by weight.
The following is desirable. By containing silicon oxide in such a ratio, an excessive reaction with the piezoelectric / electrostrictive material is avoided during heat treatment of the piezoelectric / electrostrictive drive portion formed on the second substrate, and good actuator characteristics are obtained. In getting
It is valid.

Furthermore, in the piezoelectric / electrostrictive actuator according to the present invention, in order to obtain its high-speed response and large displacement, the thickness of the second ceramic substrate (8) on which the piezoelectric / electrostrictive drive section is formed, in other words, If so, the thickness of the thin wall portion (8a) is generally 50 μm or less, preferably 30 μm or less,
It is more desirable that the thickness be 15 μm or less. On the other hand, the thickness of the first ceramic substrate (4, 12, 18) is generally 30 μm or more, preferably 50 μm or more,
More preferably, the thickness is 100 μm or more.
In order to obtain a large displacement and a large generative force as an actuator, at least the second ceramic substrate preferably has an average crystal grain size of 0.1 to 2 μm, more preferably 1 μm or less. Is desirable.

Incidentally, such a ceramic substrate (2, 1
0, 16, 38) can be processed / molded by, for example, a first substrate having holes or cutouts of a predetermined size, a flat second substrate, and a green sheet state. In addition to the green sheet laminating method of laminating in, various molding methods such as pressure molding using a molding die, casting molding, injection molding, and mechanical processing such as ultrasonic processing, cutting and grinding, Examples of the method include a processing method for forming a notched portion (recess), and among them, a green sheet laminating method is preferably used because it does not leave a processing stress and the plate thickness of a thin wall portion is highly accurate. In this green sheet laminating method, preferably,
Both green sheets are laminated by thermocompression bonding and then fired to be integrated. Further, in the integration, the first substrate and the second substrate do not necessarily have to have the same thickness, but it is desirable to use a green sheet that has at least about the same shrinkage factor by firing. ..

Further, the first substrate is provided with a hole (6, 6) having a predetermined size in a portion where the piezoelectric / electrostrictive drive portion is formed.
14 and 42) or the cutout portions (20) are formed, the formation of the voids or cutout portions is performed by forming the green sheet in advance so as to have the voids or cutout portions. In addition to the method, it is preferably carried out by adopting a method using laser processing, press machining with a die, ultrasonic machining, etc. Among them, the die machining is excellent in mass productivity and integration. Therefore, it is advantageously used. Further, although these processings can be performed after firing the substrate, more preferably, they are performed at the time of the green sheet.

The shape of such a ceramic substrate,
Furthermore, the shape of the holes or cutouts provided on the first substrate is not limited to the rectangular shape as illustrated, and any shape can be adopted according to the application. , Various shapes such as a circular shape, an oval shape, an R-shaped square, an R-shaped rectangular, a capsule shape, various polygonal shapes, and a composite shape combining them can be adopted, but in particular,
A shape having rounded corners, such as an R-shaped square, an R-shaped rectangular, a capsule shape (oval), a circle, an ellipse, or the like is preferable.

The formation of the piezoelectric / electrostrictive drive section on such a ceramic substrate is performed as follows.

First, when the bulk of the piezoelectric / electrostrictive material is used, a piezoelectric / electrostrictive material green body obtained by a press molding method using a die or a tape molding method using a slurry raw material is used. The unfired ceramic laminated substrate is laminated by thermocompression bonding on the thin-walled surface (8a),
There is a method of simultaneously firing the electrostrictive drive section. In this case, it is necessary to previously form the electrodes on at least the laminated substrate side or the piezoelectric / electrostrictive molded body side by a film forming method described later.

Further, a piezoelectric / electrostrictive material molded body obtained in the same manner as above is fired, and the obtained sintered body is subjected to the above-mentioned sintering through an adhesive to obtain a thin wall surface of the ceramic laminated substrate. There is also a method of forming it by pasting on it, and in this case also, it is necessary to previously form the electrode on at least the laminated substrate side or the piezoelectric / electrostrictive molded body side by the film forming method described later. It is preferable that the adhesive has conductivity.

The firing temperature of the piezoelectric / electrostrictive material is preferably about 800 ° C. to 1400 ° C., preferably 1000 ° to 1400 ° C. In this case, in order to control the composition, it is preferable to perform firing in the presence of an evaporation source of the piezoelectric / electrostrictive material and control the atmosphere.

On the other hand, when the piezoelectric / electrostrictive drive portion is formed by the film forming method, it is carried out as follows.

First, an electrode film (26, 3) made of each material
0) and the piezoelectric / electrostrictive film (28) on the ceramic substrate (2
2) For forming on top, various known film forming methods, for example, thick film method such as screen printing, coating method such as dipping, ion beam, sputtering, vacuum deposition, ion plating, CVD, plating, etc. The thin film method and the like can be appropriately adopted, but the method is not limited thereto. Incidentally, in order to form the piezoelectric / electrostrictive film (28), it is preferable to adopt a method such as screen printing, dipping or coating. This is because these methods can form a film on a substrate by using a paste or slurry containing piezoelectric / electrostrictive ceramic particles as a main component, and excellent actuator characteristics can be obtained. In addition, when the piezoelectric / electrostrictive drive section is formed by the film forming method in this manner, the piezoelectric / electrostrictive drive section can be integrated with the ceramic substrate without using an adhesive or the like, and therefore, the reliability and reproducibility are excellent, It is particularly preferable because it can be easily integrated. In addition, as the shape of such a film, in addition to pattern formation using a screen printing method, a photolithography method, etc., a mechanical processing method such as a laser processing method, slicing, or ultrasonic processing is used to remove unnecessary portions. Then, a pattern may be formed.

Further, the structure of the actuator to be manufactured and the shape of the film are not limited in any way, and any shape can be adopted according to the application, for example, a polygon such as a triangle, a quadrangle, a circle, an ellipse, A circular shape such as an annular shape, a comb shape, a lattice shape, or a special shape in which these are combined does not matter.

Then, the respective films (26, 28, 30) thus formed on the ceramic laminated substrate.
May be heat-treated to form an integral structure with the substrate each time each film is formed, or after forming all films, heat-treating at the same time to integrally bond each film to the substrate. You may do it. When the electrode film is formed by the thinning method, the heat treatment may not always be necessary for the integration.

Further, the heat treatment temperature for integrating the formed film and the substrate is generally 800.degree.
A temperature of about 1400 ° C is adopted, preferably 1000
Temperatures in the range of ℃ to 1400 ℃ are advantageously selected. When the piezoelectric / electrostrictive film (28) is heat-treated, the atmosphere of the piezoelectric / electrostrictive material is controlled together with the evaporation source of the piezoelectric / electrostrictive material so that the composition of the piezoelectric / electrostrictive film does not become unstable at high temperatures. It is preferable to perform heat treatment while performing.

The material of the electrode films (26, 30) constituting the piezoelectric / electrostrictive drive section produced by the above method is a conductor that can withstand a high temperature oxidizing atmosphere at the heat treatment temperature and the firing temperature. There is no particular limitation as long as it is a single metal or an alloy,
Further, it does not matter if it is a mixture of an additive such as insulating ceramics or glass and a metal or an alloy, or even a conductive ceramic. More preferably, an electrode material containing a high melting point noble metal such as platinum, palladium, rhodium, or an alloy such as silver-palladium, silver-platinum, or platinum-palladium as a main component is preferably used.

Further, in the above mixture, as the ceramics to be added to the metal or alloy, it is desirable to use the same material as the above-mentioned substrate material or the piezoelectric / electrostrictive material described later, and the addition amount thereof is the same as that of the substrate. The material is preferably 5 to 30% by volume, and the same material as the piezoelectric / electrostrictive material is preferably about 5 to 20% by volume. In particular, a mixture obtained by mixing both the substrate material and the piezoelectric / electrostrictive material with the above metal or alloy is advantageously used for forming the intended electrode.

The electrode material as described above may be heat treated at the same time as the piezoelectric / electrostrictive material or the substrate material.
Alternatively, it is advantageously used when exposed to the environment for heat treatment of the piezoelectric / electrostrictive material. Further, in the actuator structure using the bulk, when heat-treating only the electrode alone, or for the second electrode film in the actuator having the film structure, a material such as gold or silver is used in addition to the above electrode material. It is also possible.

The electrode formed by using such a material has an appropriate thickness according to the application, but as shown in FIGS. In the type that uses the lateral effect, it is generally 15μ
m or less, preferably 5 μm or less, while the type using the longitudinal effect of the electric field induced strain as shown in FIGS. 12, 14 and 15 has a thickness of 3 μm.
The thickness is preferably m or more, preferably 10 μm or more, and more preferably 20 μm or more.

In addition, the piezoelectric / electrostrictive drive section is composed of piezoelectric /
The electrostrictive material can be formed by using any material as long as it exhibits electric field induced strain such as piezoelectric or electrostrictive effect. A crystalline material or an amorphous material can be used. , A semiconductor material, a dielectric ceramic material, a ferroelectric ceramic material, or any material requiring polarization treatment,
It may also be an unnecessary material.

However, the piezoelectric / electrostrictive material used in the present invention is preferably lead zirconate titanate (PZT).
Lead-based magnesium niobate (P)
MN-based material, lead nickel niobate (P
NN-based) -based material, lead zinc niobate-based material, lead manganese lead-niobate-based material,
A material containing lead antimony stannate as a main component, a material containing lead titanate as a main component, a material containing barium titanate as a main component, and further a composite material of these are used. Note that P
A material containing an oxide of lanthanum, barium, niobium, zinc, nickel, manganese, etc. as an additive to a material containing ZT as a main component, for example, PLZT
It does not matter at all to add predetermined additives to the above materials so as to form a system.

In the actuator having the structure according to the present invention, in view of the characteristics of the actuator, | d ₃₁ | is 50 × 10 ⁻¹² [C / N] or more or | d ₃₃ | Materials having a ^{density of} 100 × 10 ⁻¹² [C / N] or more, especially | d ₃₁ | of 100 × 10 ⁻¹² [C / N]
A material having the above or | d ₃₃ | of 200 × 10 ⁻¹² [C / N] or more can be advantageously used as a piezoelectric / electrostrictive material.

The thickness of the piezoelectric / electrostrictive drive section is as follows.
Generally, it is desirable that the thickness is 100 μm or less, preferably 50 μm or less, and more preferably 30 μm or less.

Although the present invention has been specifically described based on some embodiments, the present invention should not be construed as being limited to the above embodiments, and the scope of the present invention. It is to be understood that various changes, modifications, improvements, etc. can be made based on the knowledge of those skilled in the art without departing from the above.

[Brief description of drawings]

FIG. 1 is a bottom view showing an example of a ceramic substrate according to the present invention.

2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a bottom view showing another example of the ceramic substrate according to the present invention.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a perspective explanatory view showing a state before integration of the first and second substrates in a further different example of the ceramic substrate according to the present invention.

6 is a perspective explanatory view showing a ceramic substrate formed by integrating the first and second substrates in FIG.

7 is a sectional view taken along line VII-VII in FIG.

FIG. 8 is an explanatory view showing a bottom surface of a ceramic substrate according to still another example of the present invention.

9 is a cross-sectional explanatory view showing a state before integration of the first and second substrates in the IX-IX cross section of FIG. 8;

10 is a cross-sectional explanatory view showing a state after the first and second substrates of FIG. 9 are integrated.

FIG. 11 is a perspective partial explanatory view showing an embodiment of the piezoelectric / electrostrictive actuator according to the present invention.

FIG. 12 is a perspective partial explanatory view showing another embodiment of the piezoelectric / electrostrictive actuator according to the present invention.

FIG. 13 is a perspective partial explanatory view showing still another embodiment of the piezoelectric / electrostrictive actuator according to the present invention.

FIG. 14 is a perspective partial explanatory view showing still another embodiment of the piezoelectric / electrostrictive actuator according to the present invention.

FIG. 15 is a perspective partial explanatory view showing still another embodiment of the piezoelectric / electrostrictive actuator according to the present invention.

FIG. 16 is a perspective partial explanatory view showing still another embodiment of the piezoelectric / electrostrictive actuator according to the present invention.

[Explanation of symbols]

 2, 10, 16, 22, 38: Ceramic substrate 4, 12, 18, 40: First substrate 6, 14, 42: Hole portion 20: Cutout portion 8: Second substrate 26: First electrode 28 : Piezoelectric / electrostrictive layer 30: Second electrode 32: Strip electrode film

Claims (9)

[Claims] 1. A piezoelectric / electrostrictive actuator comprising a ceramic substrate and a piezoelectric / electrostrictive drive section,
A recess of a predetermined size is formed in the ceramic substrate, the bottom of the recess is a thin wall portion, and the piezoelectric / electrostrictive drive unit is provided on the surface of the thin wall portion of the ceramic substrate. A piezoelectric / electrostrictive actuator characterized in that the piezoelectric / electrostrictive actuator is formed. 2. A piezoelectric / electrostrictive actuator comprising a ceramic substrate and a piezoelectric / electrostrictive drive section,
The ceramic substrate is laminated on a first substrate having pores or cutouts of a predetermined size with a flat second substrate in the state of a green sheet and fired to form the pores or A recess is formed in the recess, and a bottom portion of the recess is a thin-walled portion to form an integrated laminated ceramic substrate, and the piezoelectric / electrostrictive drive unit is further formed into the laminated ceramic substrate. A piezoelectric / electrostrictive actuator formed on the surface of the thin wall portion. 3. The piezoelectric / electrostrictive actuator according to claim 1, wherein the piezoelectric / electrostrictive drive section is formed by film formation. 4. The ceramic substrate is made of a material containing any of aluminum oxide, magnesium oxide, zirconium oxide, aluminum nitride and silicon nitride as a main component. Piezoelectric / electrostrictive actuator. 5. A material containing zirconium oxide as a main component, wherein the ceramic substrate is stabilized with at least one compound selected from the group consisting of yttrium oxide, ytterbium oxide, cerium oxide, calcium oxide and magnesium oxide. The piezoelectric / electrostrictive actuator according to any one of claims 1 to 4, wherein 6. The ceramic substrate, wherein at least the second substrate is made of a ceramic material having a silicon oxide content of 0.5 wt% or more and 5 wt% or less. 5. The piezoelectric / electrostrictive actuator according to any one of 5 above. 7. The piezoelectric / electrostrictive device according to claim 1, wherein two or more piezoelectric / electrostrictive drive units are provided on the surface of the ceramic substrate in a laminated form or in a juxtaposed form. Actuator. 8. The piezoelectric / electrostrictive actuator according to claim 1, wherein in the plate thickness of the ceramic substrate, at least the thin wall portion is 50 μm or less. 9. The thickness of the piezoelectric / electrostrictive drive unit is 100.
9. The piezoelectric according to claim 1, which has a thickness of μm or less.
Electrostrictive actuator.