JP2001169571A - Piezoelectric and electrostrictive device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacing element capable of largely operating a movable unit and having excellent mechanical strength, handleability, impact resistance and moisture resistance, and hardly effected by an influence of a harmful vibration in operation and a sensor element capable of accurately detecting the vibration of the unit. SOLUTION: The piezoelectric and electrostrictive device 1 comprises a driver 3 driven by the displacement of a piezoelectric and electrostrictive element, a movable unit 4 operated based on the drive of the driver 3, and a fixing unit 5 for supporting the driver 3 and the unit 4. In the device 1, the driver 3 has opposed thin plates 6, 7 and a thin film-like piezoelectric and electrostrictive element 2 formed on the surface of the at least one plate 6 of the plates 6, 7, and the unit 5 is connected to the unit 4 by the driver 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a piezoelectric / electrostrictive device having a movable portion that operates based on the displacement of a piezoelectric / electrostrictive element, or a piezoelectric / electrostrictive device capable of detecting the displacement of a movable portion by the piezoelectric / electrostrictive element. For details on electrostrictive devices,
The present invention relates to a piezoelectric / electrostrictive device having excellent shock resistance and moisture resistance, high amplitude efficiency, and capable of largely operating a movable portion.

[0002]

2. Description of the Related Art In recent years, in the fields of optics, magnetic recording, precision processing, and the like, displacement elements capable of adjusting the optical path length and position on the order of submicrons have been required, and piezoelectric / electrostrictive materials (for example, ferroelectric materials) have been required. Etc.), displacement elements utilizing displacement caused by an inverse piezoelectric effect or an electrostrictive effect caused when a voltage is applied are being developed.

For example, as shown in FIG. 2, by providing a hole 28 in a plate made of a piezoelectric / electrostrictive material, a fixed portion 25, a movable portion 24, and a beam portion 26 connecting these are integrally formed. A piezoelectric actuator 21 which is formed and further provided with an electrode layer 22 on a beam portion 26 is disclosed (JP-A-10-13666).
No. 5).

In the actuator 21, when a voltage is applied to the electrode layer 22, the beam portion 26 expands and contracts in a direction connecting the fixed portion 25 and the movable portion 24 by an inverse piezoelectric effect or an electrostrictive effect. It is possible to make an arcuate or rotational displacement in the plane of the body.

[0005]

However, in the actuator 21, the displacement in the expansion / contraction direction of the piezoelectric / electrostrictive material (that is, the in-plane direction of the plate-shaped body) is transmitted to the movable portion as it is, so that the movable portion 24 There is a problem that the operation amount of the is small.

Further, since all parts of the actuator 21 are made of a piezoelectric / electrostrictive material that is a fragile and relatively heavy material, the mechanical strength is low, and the handleability, impact resistance, and moisture resistance are poor. In addition, there is a problem that the actuator 21 itself is heavy and susceptible to harmful vibrations (for example, residual vibration or noise vibration during high-speed operation) in operation.

In the actuator 21, it has been proposed to fill the hole 28 with a flexible filler in order to solve the above problem. However, when the filler is used, the inverse piezoelectric effect or the electrostriction It is clear that the displacement efficiency due to the effect is reduced.

The present invention has been made in view of such problems of the related art, and an object of the present invention is to make it possible to largely operate a movable portion and to make the operation harmful. An object of the present invention is to provide a displacement element which is hardly affected by vibration and has excellent mechanical strength, handling properties, impact resistance and moisture resistance, and a sensor element which can accurately detect vibration of a movable part.

[0009]

That is, according to the present invention, a drive section driven by displacement of a piezoelectric / electrostrictive element, a movable section which operates based on the drive of the drive section, the drive section and the movable section Piezoelectric device with a fixed part for supporting the part
The electrostrictive device includes a driving unit including a thin plate facing each other and a thin-film piezoelectric / electrostrictive element formed on a surface of at least one of the thin plates. A piezoelectric / electrostrictive device is provided, wherein the piezoelectric / electrostrictive device is coupled to the movable portion.

As a specific mode of the piezoelectric / electrostrictive device according to the present invention, a thin plate facing each other such that the movable portion and the fixed portion have a rectangular parallelepiped shape and the side surfaces of the movable portion and the fixed portion are continuous. Are straddled. In the piezoelectric / electrostrictive device of the present invention, the driving unit is driven in a direction orthogonal to the displacement direction of the piezoelectric / electrostrictive element, and the movable unit operates in a plane including the driving direction of the driving unit. . Further, it is also possible to use the driving section for detecting the displacement of the movable section.

Further, the piezoelectric / electrostrictive device of the present invention comprises:
The one having at least two or more drive units is preferable, and the width of the thin plate is preferably five times or more the thickness of the thin plate.

As the piezoelectric / electrostrictive element constituting the piezoelectric / electrostrictive device of the present invention, a laminated piezoelectric / electrostrictive element in which a lower electrode, a piezoelectric / electrostrictive film, and an upper electrode are stacked, or a piezoelectric / electrostrictive element, A structure comprising an electrostrictive film, a first electrode and a second electrode having a comb structure, wherein the first electrode and the second electrode are intermeshed with each other with a fixed width gap between the teeth of the combs. And a piezoelectric / electrostrictive element having the following.

In the piezoelectric / electrostrictive device according to the present invention, it is preferable that the movable portion, the thin plate, and the fixed portion are made of integrally formed ceramic, and the movable portion, the thin plate, and the fixed portion are completely stabilized zirconia. Alternatively, those made of partially stabilized zirconia are more preferable, and those in which at least the movable part, the thin plate, and the fixed part are made of a green sheet laminate are particularly preferable.

In the piezoelectric / electrostrictive device according to the present invention, the piezoelectric / electrostrictive film constituting the piezoelectric / electrostrictive element is made of a material mainly composed of lead zirconate, lead titanate, and lead magnesium niobate. Of a material containing sodium bismuth titanate as a main component is also preferable.

Further, according to the present invention, a driving unit composed of opposed thin plates and a thin-film piezoelectric / electrostrictive element formed on the surface of at least one of the thin plates is fixed in a rectangular parallelepiped shape. A piezoelectric and electrostrictive device manufacturing method comprising: a movable portion and a movable portion, wherein the movable portion and the fixed portion have side surfaces continuous with each other, and opposed thin plates are straddled. A step of stacking at least one or more green sheets, a green sheet in which one or more rows of rectangular holes are formed, and a green sheet to be the thin plate, to obtain an integrated laminate, and a thick film method or a thin film method. Forming a piezoelectric / electrostrictive element on the surface of the green sheet to be a thin plate, and firing the laminate, so that the rectangular holes are opened on the side surfaces of the laminate; Cutting in the stacking direction A method for manufacturing a piezoelectric / electrostrictive device is provided.

Further, according to the present invention, there is provided an optical shutter for controlling transmission and shielding of light by relatively moving two shielding plates, wherein at least one of the shielding plates is provided with the above-mentioned piezoelectric plate. An optical shutter mounted on a movable part of an electrostrictive device is provided.

[0017]

Hereinafter, a piezoelectric / electrostrictive device according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the illustrated embodiment. In the following description, “piezoelectric” may mean “piezoelectric and / or electrostrictive” in some cases. Further, “length” is a distance in a direction (Z-axis direction in the figure) connecting the movable part and the fixed part, “width” is a distance in a hole penetrating direction (Y-axis direction in the figure), and “thickness” is Lamination direction of piezoelectric element and thin plate (X in the figure)
(Axial direction).

[0018] 1. Embodiment of Device The term “piezoelectric / electrostrictive device” (hereinafter simply referred to as “device”) as used in the present specification includes elements that mutually convert electric energy and mechanical energy by using a piezoelectric / electrostrictive material. It is a concept to do. Therefore, it is preferably used as an active element such as various actuators and vibrators, particularly as a displacement element utilizing displacement due to an inverse piezoelectric effect or an electrostrictive effect, but also as a passive element such as an acceleration sensor element or an impact sensor element. Can be used.

FIG. 1 is a schematic perspective view showing one embodiment of the device of the present invention. Device 1 is a piezoelectric element 2
The driving unit 3 is driven by the displacement of the driving unit 3, a movable unit 4 that operates based on the driving of the driving unit 3, and a fixed unit 5 that supports the driving unit 3 and the movable unit 4.

The driving unit 3 includes thin plates 6 and 7 facing each other and a thin-film piezoelectric element 2 formed on the surface of the thin plate 6, and the movable unit 4 and the fixed unit 5 are connected by the thin plates 6 and 7. Have been. Therefore, a hole 8 is formed in the device 1 in a direction perpendicular to the facing surfaces of the thin plates 6 and 7 facing each other.

As shown in FIG. 3, in the device 1, since the piezoelectric element 2 is formed on the surface of the thin plate 6, the driving unit is driven in a direction orthogonal to the displacement direction of the piezoelectric element (a in the figure) (FIG. Middle b). That is, after amplifying a minute displacement in the expansion and contraction direction of the piezoelectric element 2 into a large drive using the bending of the thin plate 6,
Since the light is transmitted to the movable part 4, the movable part 4 can be largely operated (c in the figure).

The device 1 is not a plate-like body, but the movable part 4 and the fixed part 5 are rectangular parallelepiped, and the movable part 4 and the fixed part 5
Since the thin plates 6 and 7 are straddled so that the side surfaces of the device are continuous, it is possible to selectively increase the rigidity of the device in the Y-axis direction. That is, in the device 1, only the arc-shaped operation of the movable section 4 in a plane including the driving direction of the drive section 3 (ie, in the XZ plane) can be selectively generated, and the movable section 4 in the YZ plane can be generated. It is possible to suppress the operation (the operation in the so-called tilting direction).

It is sufficient that the piezoelectric element is formed on the surface of at least one of the opposed thin plates as in the device 1. However, the piezoelectric element is provided on both of the opposed thin plates 36 as in the device 31 shown in FIG. The element 32 may be formed. In such a configuration, by driving one of the piezoelectric elements 32 formed on the thin plates 36 and 37, the movable portion 34 can be operated in an arc shape in the XZ plane, similarly to the device 1. By synchronously driving the two piezoelectric elements 32, an operation of expanding and contracting the movable portion 34 in the Z-axis direction can be obtained.

Further, by separately controlling the two piezoelectric elements 32 and providing a difference in the amount of displacement, it is possible to easily obtain an operation in which an arc-shaped operation in the XZ plane and an operation of expanding and contracting in the Z-axis direction are combined. it can. That is, as shown in FIG.
The device 61 of the present invention operates such that the movable portion operates in an arc shape (e in the figure) or expands and contracts (f in the diagram) in a plane including the driving direction d of the piezoelectric element constituting the driving portion;
Alternatively, it operates in a direction in which these are combined.

Furthermore, one of the two piezoelectric elements 32 can be a driving element and the other can be a vibration detecting element. In other words, by using the drive unit of the device to detect the displacement of the movable unit, it can be made to function as an acceleration sensor or an impact sensor. If the voltage applied to the drive element is controlled based on the signal, more precise control of the operation amount is possible. In addition, it is possible to detect the vibration of the part where the piezoelectric / electrostrictive device is installed, and apply an opposite-phase operation to cancel the vibration to the movable part, resulting in the effect of suppressing the relative vibration of the movable part. is there.

Further, it is not necessary to form one piezoelectric element for each thin plate, and the piezoelectric element may be divided into a plurality of parts as necessary. For example, when divided in the width direction as shown in FIG. 5A, the displacement can be controlled for each piezoelectric element, so that the displacement in the YZ plane (so-called tilting component) can be suppressed,
On the other hand, when divided in the length direction as shown in FIG. 5 (b), it is easy to bend at the divided portion, so that the operation amount of the movable portion increases and the resolution of the operation amount can be improved. Becomes Further, even when the piezoelectric element is divided, one of the piezoelectric elements can be used as a driving element and the other piezoelectric element can be used as a detecting element, so that a highly accurate detection and control can be achieved with a compact structure.

When the piezoelectric element for each thin plate is divided as described above, a slit 49 may be provided between the divided piezoelectric elements 42-42 as shown in FIGS. 5 (c) and 5 (d). preferable. In such a configuration, since the thin plate is easily bent at the slit portion, each piezoelectric element 42 is easily displaced, and as a result, there is an advantage that the displacement of the piezoelectric element 42 can be efficiently transmitted to the movable portion.

Further, as shown in FIG.
The device 51 provided above is also preferable. In this case, since the driving amount of each driving unit 53 is synergistically transmitted as compared with the case where the number of driving units is one, the movable unit 54 can be operated to a greater extent.

Further, when there are two or more driving units, the movable unit and the fixed unit do not necessarily have to be at both ends of the device, and as shown in FIG.
The movable section 54 may be arranged between the 5-55. In such a configuration, although the operation amount of the movable portion is reduced, the device 5
1 can be reliably fixed, so that mechanical strength and impact resistance can be improved, and there is an advantage that operation in the YZ plane (operation in the so-called tilting direction) can be suppressed.

When a plurality of driving units are provided as described above, the gap 59 between the driving units 53 to 53 may be configured to be shorter than the fixed unit 55 and the movable unit 54 as shown in FIG. preferable. This is because the operation amount increases.

Further, as shown in FIG. 9, the length of each drive unit 53 may be shortened toward the movable unit 54. With such a configuration, while the drive unit 53 secures the drive amount in the long part, the drive unit 53 can perform fine control of the drive amount in the short part, so that the movable unit can be largely operated, and This is preferable in that fine adjustment is possible.

Further, although there is a balance with mechanical strength, a device in which a notch portion 60 is formed between the driving portions 53 as shown in FIG. 10 is also preferable. Cut part 6
At 0, the thin plate 56 is easily bent, and the operation amount of the movable portion can be increased.

In addition to the above-described effects, the device of the present invention does not necessarily need to be entirely made of a piezoelectric / electrostrictive material. There is an advantage that a constituent material can be appropriately selected according to the situation. That is, by configuring members other than the piezoelectric / electrostrictive elements with a lightweight material, it is possible to make the operation less susceptible to harmful vibration. It is easy to improve impact resistance and moisture resistance. Further, since there is no need to use a filler, the efficiency of displacement due to the inverse piezoelectric effect or the electrostriction effect does not decrease.

[0034] 2. Components of Device Next, each component of the device of the present invention will be specifically described with reference to the example of the device 1 shown in FIG.

(1) Movable Part and Fixed Part The movable part 4 is a part that operates based on the drive amount of the drive part 3, and various members are attached according to the purpose of use of the device 1. For example, when the device 1 is used as a displacement element, a member that requires position adjustment, such as a shield plate of an optical shutter and a magnetic head, may be attached.

The fixed part 5 is a part that supports the driving part 3 and the movable part 4, and the entire device 1 is fixed by supporting and fixing the fixed part 5 to some kind of base. Further, an electrode lead for controlling the piezoelectric element 2 and other members may be arranged.

The material constituting the movable portion 4 and the fixed portion 5 is not particularly limited as long as it has rigidity, but a ceramic to which a green sheet laminating method described later can be applied can be suitably used. Specifically, zirconia including stabilized zirconia, partially stabilized zirconia, alumina, magnesia, silicon nitride, and the like, and in terms of high mechanical strength and toughness, zirconia,
Particularly, stabilized zirconia and partially stabilized zirconia are preferable.

(2) Driving Unit The driving unit 3 is a part driven by the displacement of the piezoelectric element 2. The driving unit 3 is composed of the thin plates 6 and 7 facing each other and the thin-film piezoelectric element 2 formed on the surface of the thin plate 6. It is configured.

The thin plates 6 and 7 are flexible thin plate-shaped members, and have a function of amplifying expansion and contraction displacement of the piezoelectric element 2 disposed on the surface as bending displacement and transmitting the amplified displacement to the movable portion 4. Therefore, the shape and material of the thin plates 6 and 7 are only required to be flexible as long as they have mechanical strength enough not to be damaged by flexural deformation. You can choose.

Usually, the thickness of the thin plates 6 and 7 is 5 to 100 μm.
m, and the thin plates 6 and 7 and the piezoelectric element 2
Is preferably 10 to 500 μm. Further, the width of the thin plates 6 and 7 is preferably 30 to 500 μm, and the displacement in the YZ plane, that is, the tilting component is suppressed,
From the viewpoint of effectively generating displacement in the XZ plane, the thickness is preferably 5 times or more, and more preferably 8 times or more, the thickness of the thin plates 6 and 7.

As a material for forming the thin plates 6 and 7, the same ceramic as that of the movable portion 4 and the fixed portion 5 can be suitably used. Zirconia, and in particular, stabilized zirconia and partially stabilized zirconia, may be formed in a thin plate shape. It is most preferably employed because of its high mechanical strength, high toughness, and low reactivity with piezoelectric films and electrode materials. In addition, thin plate 6,
When using stabilized zirconia or partially stabilized zirconia as the material of No. 7, it is preferable to add an additive such as alumina or titania in that the residual stress during firing of the piezoelectric film can be reduced.

Piezoelectric Element The piezoelectric element 2 is composed of a piezoelectric film and electrodes for applying a voltage to the piezoelectric film, and a conventionally known piezoelectric element such as a unimorph type or a bimorph type can be used. For example, as shown in FIG.
c, a laminated piezoelectric element 62 in which the piezoelectric film 62a and the upper electrode 62b are laminated can be preferably used.

As shown in FIG. 13, the first electrode 72b and the second electrode 72c have a comb structure, and the first electrode 72b and the second electrode 72c are fixed between the teeth of the comb. It is also possible to use a piezoelectric element 72 having a structure that engages with each other with a gap 73 having a width. In FIG. 13, the first
The electrode 72b and the second electrode 72c are connected to the thin plate 76, the piezoelectric film 72a.
, But an electrode may be formed between the thin plate 76 and the piezoelectric film 72a.

Further, the piezoelectric element 82 shown in FIG. 14 also includes a first electrode 82 b and a second electrode 82 c having a comb structure,
The first electrode 82b and the second electrode 82c have a structure in which they engage with each other with a gap 83 having a fixed width between the teeth of the combs. The piezoelectric element 82 is configured so that the piezoelectric film 82a is buried in the gap between the first electrode 82b and the second electrode 82c, but such a piezoelectric element can also be suitably used for the device of the present invention. Piezoelectric elements 72, 82
When using a piezoelectric element having a comb-shaped electrode as in
By reducing the pitch D of the teeth of the comb, the displacement of the piezoelectric element can be increased.

The piezoelectric element 2 is preferably formed on the outer surface side of the device 1 as in the device 1 shown in FIG. 1 in that the driving unit can be driven to a greater extent. That is, it may be formed on the inner surface side and the outer surface side of the device 1.

As the piezoelectric film, piezoelectric ceramic is preferably used, but it is also possible to use electrostrictive ceramic, ferroelectric ceramic, or antiferroelectric ceramic. However, when used for a magnetic head or the like, since the linearity between the operation amount of the movable part and the drive voltage or the output voltage is important, it is preferable to use a material having a small strain history, and the pit electric field is 10 kV / mm or less. It is preferable to use the above material.

Specific piezoelectric ceramics include lead zirconate, lead titanate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, lead manganese niobate, lead antimony stannate, lead manganese tungstate,
Ceramics containing lead cobalt niobate, barium titanate, sodium bismuth titanate, potassium sodium niobate, strontium bismuth tantalate alone or as a mixture can be used. In particular, lead zirconate and titanic acid have a high electromechanical coupling coefficient and a piezoelectric constant, have low reactivity with a thin plate (ceramic) during sintering of a piezoelectric film, and have a stable composition. A material mainly containing lead and lead magnesium niobate or a material mainly containing sodium bismuth titanate is preferably used.

Further, lanthanum, calcium, strontium, molybdenum, tungsten, barium, niobium, zinc, nickel, manganese, cerium, cadmium, chromium, cobalt, antimony, iron, yttrium, tantalum, lithium, bismuth, Ceramics in which oxides such as tin or the like are used alone or in combination may be used. For example, by adding lanthanum or strontium to lead zirconate, lead titanate, and lead magnesium niobate, which are the main components, advantages such as the ability to adjust the anti-field and piezoelectric characteristics can be obtained.

On the other hand, the electrodes of the piezoelectric element are preferably solid at room temperature and made of a metal having excellent conductivity, for example, aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, A single metal such as niobium, molybdenum, ruthenium, palladium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead or an alloy thereof is used, and the same material as the piezoelectric film or thin plate is dispersed therein. You may use the cermet material which made it.

The selection of the material of the electrode in the piezoelectric element is determined depending on the method of forming the piezoelectric film. For example, when forming a first electrode on a thin plate and then forming a piezoelectric film on the first electrode by firing, a high melting point metal such as platinum which does not change even at the firing temperature of the piezoelectric film is used for the first electrode. Although the second electrode formed on the piezoelectric film after the piezoelectric film is formed can be formed at a low temperature, a low-melting metal such as aluminum can be used.

Although various forms of electrode leads from the piezoelectric element are conceivable, for example, as shown in FIG. 15, a device 91 in which the piezoelectric element 92 is formed on both of the opposed thin plates 96.
In this case, the lower electrode 92c of the two piezoelectric elements 92 is made common, and the lower electrode 92c is pulled out to the fixed part 95 side of one surface where the hole 98 is opened.
A mode in which the surface is directly drawn to the fixing portion 95 side of the forming surface is exemplified. In such an embodiment, an electrode is not formed in a portion (99 in the figure) on the fixing portion 95 side of the other surface where the hole 98 is opened, and the device can be fixed using the portion. This is preferable in that the device can be fixed with high reliability and can be made compact.

Further, as shown in FIG. 16A, the upper electrode 92 b and the lower electrode 92 c are both drawn out so as to be parallel to the fixed part 95 side of the surface on which each piezoelectric element 92 is formed, or as shown in FIG. 16B. The upper electrode 92b and the lower electrode 92
Alternatively, both c may be separated and pulled out to the movable part 94 side and the fixed part 95 side of each piezoelectric element 92 formation surface.

[0053] 3. Device Manufacturing Method Here, the device manufacturing method of the present invention will be described. The device of the present invention is preferably manufactured using a ceramic as a constituent material of each member and using a green sheet laminating method. According to the green sheet laminating method in which the device can be integrally formed, the reliability of the bonding portion of each member can be improved, and the device having the above-described excellent characteristics can be obtained by simplifying the manufacturing process. Can be mass-produced.

(1) Production of Laminate First, a slurry is prepared by adding a binder, a solvent, a dispersant, and the like to ceramic powder such as zirconia, and then defoaming the slurry, followed by a reverse roll coater method or a doctor blade method. A green sheet having a predetermined thickness is produced by the method described above. Next, the green sheet is processed into various shapes as shown in FIG. 17 by a method such as punching using a die.

The green sheet 101 is a green sheet that mainly becomes a thin plate after firing, and the green sheet 102 in which one or more rows of rectangular holes 103 are formed is a member that becomes a movable part and a fixed part. By forming one or more rows of holes 103 in parallel, it is possible to obtain a plurality of devices at once, or to obtain at least one device having a plurality of movable parts. By laminating at least one or more of each of the green sheets 101 and 102, a thickness required for a thin plate, a movable portion, and a fixed portion can be obtained.

The green sheets 101, 102, 101
In this order, the layers are stacked while performing positioning using the reference holes 104, and integrated using a method such as thermocompression bonding to obtain a stacked body (FIG. 19A). In the case where the green sheet 102 is thick and it is difficult to form the holes 103, a stacked body 105 divided into upper and lower parts is formed as shown in FIG. 18 and then joined so that the holes 103 face each other. Then, a final laminate 108 may be obtained.

Regarding the laminate 108, a communication hole 106 between the hole 103 of the green sheet 102 and the external space is formed in the green sheet 102, or the communication hole 106 is formed after the laminate is formed. It is necessary to drill. However, as long as each hole 103 communicates with the external space, the shape of the communication hole 106 is not particularly limited, and a plurality of holes 103 are formed as shown in FIGS.
In addition to the shape penetrating through each hole, as shown in FIG.
It is good also as a shape which can be made to communicate with the external space for every three.

(2) Formation of Piezoelectric / Electrostrictive Element In the manufacturing method of the present invention, a screen printing method, dipping method,
Coating method, thick film method such as electrophoresis method or ion beam method, sputtering method, vacuum deposition, ion plating method,
The piezoelectric element 107 can be formed by a thin film method such as chemical vapor deposition (CVD) and plating (FIG. 19).
(B)).

By forming the piezoelectric element by the film forming method in this manner, the piezoelectric element and the thin plate can be integrally joined and disposed without using an adhesive, and reliability and
Reproducibility can be ensured, and integration can be facilitated.

However, in the manufacturing method of the present invention, it is preferable to form the piezoelectric element 107 by a thick film method.
According to these techniques, the piezoelectric film is formed using a paste or slurry, a suspension, an emulsion, a sol, or the like containing, as a main component, piezoelectric ceramic particles having an average particle size of 0.01 to 5 μm, preferably 0.05 to 3 μm. This is because good piezoelectric operation characteristics can be obtained. In particular, the electrophoresis method has an advantage that a film can be formed with high density and high shape accuracy.

Specifically, after firing the laminate 108 under predetermined conditions, a lower electrode is printed and fired at a predetermined position on the surface of the fired green sheet 101, and then a piezoelectric film is printed and fired. The piezoelectric element can be formed by printing and firing the upper electrode (FIG. 19B). Further, an electrode lead for connecting the electrode to the drive circuit may be printed and fired.

Here, platinum (Pt) is used as the lower electrode,
Lead zirconate titanate (PZT) as a piezoelectric film, gold (Au) as an upper electrode, and silver (A) as an electrode lead.
As shown in g), if the material is selected so that the firing temperature of each member is gradually lowered, re-sintering of the previously fired material does not occur in a certain firing step, and peeling or agglomeration of the electrode material and the like occur. It is possible to avoid the occurrence of such a problem.

By selecting an appropriate material, it is possible to sequentially print each member of the piezoelectric element 107 and the electrode lead and sinter them all at once. It is also possible to provide each electrode and the like. Further, each member of the piezoelectric element and the electrode lead may be formed by a thin film method such as a sputtering method or a vapor deposition method, and in this case, heat treatment is not necessarily required.

Note that it is also preferable that the piezoelectric element 107 is formed in advance on the green sheet 101 at a position where the green sheet 101 is to be finally formed into a thin plate, and that the green element 101 is fired simultaneously with the laminated body 108. As a method for simultaneously firing the piezoelectric element 107 and the laminated body 108, a piezoelectric film is formed by a press forming method using a mold or a tape forming method using a slurry raw material, and the piezoelectric film before firing is green. A method of laminating by thermocompression bonding on the sheet 101 and firing at the same time to simultaneously produce a movable portion, a driving portion, a thin plate, and a piezoelectric film. However, in this method, it is necessary to form electrodes on the thin plate or the piezoelectric film in advance by using the film forming method described above.

The firing temperature of the piezoelectric film is appropriately determined depending on the material constituting the piezoelectric film.
400 ° C., preferably 1000 ° C. to 1400 ° C. In this case, in order to control the composition of the piezoelectric film, sintering is preferably performed in the presence of an evaporation source of the material of the piezoelectric film.
When the piezoelectric film and the multilayer body 108 are simultaneously fired,
It is necessary to unify both firing conditions.

When manufacturing a device in which a piezoelectric element is formed on both opposing thin plates, a piezoelectric film, an electrode, and the like must be printed on both surfaces of the laminate. In such a case, printing is performed on a printing stage provided with a concave portion on the printing stage, or a frame-shaped convex portion is formed around a printing portion on at least one printing surface of the laminate, and the convex portion forming surface is formed. After printing, it is necessary to take measures to prevent the piezoelectric film, electrodes, and the like printed by the method of printing the other surface from adhering to the printing stage.

(3) Firing and cutting of the laminated body The above-mentioned laminated body is subjected to processing such as formation of notches, coating of piezoelectric elements and electrode leads, shielding, and the like, if necessary, at 1200 ° C. to 1600 ° C. C., and cut in the stacking direction of the green sheets so that the rectangular holes 103 are opened on the side surfaces of the stack.
A plurality of devices can be obtained simultaneously (FIG. 19).
(C)). As a cutting method, in addition to dicing, wire sawing, and the like (mechanical processing), laser processing using a YAG laser, excimer laser, or the like, or electron beam processing can be applied.

In the manufacturing method of the present invention, the laminate is cut so that the rectangular hole 103 is opened on the side surface of the laminate. Such cutting not only separates the devices, but also the thin plates and holes of the devices (device 1 in FIG. 1).
In this case, there is an advantage that the thin plates 6 and 7 and the hole 8) can be formed at one time, and it is preferable in that a complicated and difficult-to-manufacture structure in which two or more rectangular parallelepipeds are connected by the thin plate can be easily obtained.

By appropriately changing the number and position of the holes 103 formed in the green sheet 102 or the cutting position of the stacked body 108, a device having a plurality of driving units (FIGS. 6 to 8) or a driving unit Devices with different lengths (FIG. 9) can also be formed very easily.

The device of the present invention can be manufactured by using a pressing method using a molding die, a casting method, an injection molding method, or the like, in addition to the manufacturing method using the green sheet described above. it can. In addition, it is possible to use a method in which the components prepared separately are joined together to manufacture them. However, in addition to low productivity, there is also a problem in terms of reliability because breakage and the like are likely to occur at the joints. is there.

[0071] 4. Application Example of Device Lastly, as one application example of the device of the present invention, an example in which the device of the present invention is applied to a displacement element for an optical shutter will be described. "Light shutter" as used in this specification
Means a functional element that controls the transmission and shielding of light by moving the two shielding plates relatively.
Since OFF control and light amount control can be performed, it is possible to function as an optical switch or an optical stop.

The optical shutter of the present invention is one in which at least one of the two shielding plates is attached to the movable part of the device of the present invention. For example, FIG.
The optical shutter 110 shown in (b) is composed of two units 111A and 111B provided with the device of the present invention and a shielding plate, and the two shielding plates 113A and 113B are respectively attached to the movable parts 114A and 114B of the device. attachment,
The plates are arranged such that their flat surfaces are parallel to each other and a part of the flat surfaces overlaps with the incident direction of the light L.

The optical shutter 110 shields the light L in the state shown in the figure, but by applying a voltage of the same phase to the piezoelectric elements 112 A and 112 B formed in the drive unit of the device, the shielding plate 113 A To the left, shielding plate 113
B moves to the right side in the figure, so that the shielding plates 113A, 113B
, The ON / OFF control of light and the light quantity control can be performed.

The optical shutter 120 shown in FIG. 21A is composed of two units 121 and 122 each including a device of the present invention and a shielding plate, and the two shielding plates 123 A and 123 B are respectively connected to the device. Movable part 124
A, 124B, the planes of each other become parallel,
In addition, they are arranged such that the entire flat plate surface overlaps with the incident direction of the light L. And the shielding plates 123A, 123B
Are formed with slits 125A and 125B at opposing positions.

The optical shutter 120 is provided as shown in FIG.
In the state of (b), the light L is transmitted through the slits 125A and 125B, but by applying the same phase voltage to the piezoelectric elements 122A and 122B formed in the drive unit of the device, the shielding plate 123A moves to the left side in the figure. Since the shielding plate 123B moves to the right side in the figure, the degree of overlap between the slits 125A and 125B changes, so that ON / OFF control of light and light amount control can be performed. FIG. 21 (c) shows a state where some light is transmitted, but the slits 123A and 123A are not shown.
By changing the shape and position of B, the light L can be completely blocked.

On the contrary, in the state shown in FIGS. 21A and 21B, the slits 125A and 125B are configured to block the light L without overlapping, and the slits 125A and 125B are moved by the movement of the shielding plates 123A and 123B. The structure may be such that the light L is transmitted through the overlapping portions 125B.

In the examples of FIGS. 20 and 21, two shield plates are respectively attached to the device, but the optical shutter of the present invention has at least one shield plate attached to the device and the one shield plate. It is possible to control the transmission and blocking of light only by moving. However, it is preferable to attach both shield plates to the device in that the relative movement amount of the shield plates can be increased.

In the examples of FIGS. 20 and 21, the optical shutter is constituted by two units, but may be constituted by three or more units. In this case, by setting the moving directions of the plurality of shield plates in various ways, the shield plate can be used as an optical stop or the like in which the degree of opening of the overlapping portion is changed.

In the optical shutter of the present invention, since the shielding plate is attached to the movable portion of the device of the present invention, the operation of the shielding plate in the tilting direction is suppressed. In other words, since the shielding plate always moves in the direction of light incidence, more precise light ON
/ OFF control and light quantity control can be suitably used.

[0080]

As described above, the piezoelectric and piezoelectric elements of the present invention
The electrostrictive device is capable of greatly displacing the movable part, is less susceptible to harmful vibration in operation, and is excellent in mechanical strength, handling properties, impact resistance, and moisture resistance.
In addition, by using a simple manufacturing method such as the green sheet lamination method, while improving the reliability as an integrated structure,
There is an advantage that it can be manufactured at low cost.

Accordingly, in addition to active elements such as various transducers, various actuators, frequency domain functional components (filters), transformers, transducers and resonators for communication and power, oscillators, discriminators and the like, ultrasonic sensors and Can be used as sensor elements for various sensors such as acceleration sensors, angular velocity sensors, impact sensors, mass sensors, etc.
In particular, the present invention can be suitably used for various actuators used for displacement, positioning adjustment, and angle adjustment mechanisms of various precision components such as optical devices and precision devices.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing one embodiment of a piezoelectric / electrostrictive device of the present invention.

FIG. 2 is a schematic perspective view showing one embodiment of a conventional piezoelectric actuator.

FIG. 3 is a schematic explanatory view showing an operation mode of the piezoelectric / electrostrictive device of the present invention.

FIG. 4 is a schematic perspective view showing another embodiment of the piezoelectric / electrostrictive device of the present invention.

FIGS. 5A and 5B are schematic perspective views (a) and (b) showing still another embodiment of the piezoelectric / electrostrictive device of the present invention, and explanatory views (c) to (d) showing the arrangement of slits.

FIG. 6 is a schematic perspective view showing still another embodiment of the piezoelectric / electrostrictive device of the present invention.

FIG. 7 is a schematic explanatory view showing still another embodiment of the piezoelectric / electrostrictive device of the present invention.

FIG. 8 is a schematic explanatory view showing still another embodiment of the piezoelectric / electrostrictive device of the present invention.

FIG. 9 is a schematic explanatory view showing still another embodiment of the piezoelectric / electrostrictive device of the present invention.

FIG. 10 is a schematic explanatory view showing still another embodiment of the piezoelectric / electrostrictive device of the present invention.

FIG. 11 is a schematic perspective view showing one embodiment of a piezoelectric element constituting the piezoelectric / electrostrictive device of the present invention.

FIG. 12 is a schematic explanatory view showing a relationship between a piezoelectric element constituting the piezoelectric / electrostrictive device of the present invention and an operation direction.

FIG. 13 is a schematic perspective view showing another embodiment of the piezoelectric element constituting the piezoelectric / electrostrictive device of the present invention.

FIG. 14 is a schematic perspective view showing still another embodiment of the piezoelectric element constituting the piezoelectric / electrostrictive device of the present invention.

FIG. 15 is a schematic perspective view showing one embodiment of a method for arranging electrode leads of the piezoelectric / electrostrictive device of the present invention.

FIG. 16 is a schematic explanatory view showing another embodiment of the method for arranging the electrode leads of the piezoelectric / electrostrictive device of the present invention,
(B).

FIG. 17 is a schematic explanatory view showing an example of a green sheet used for manufacturing the piezoelectric / electrostrictive device of the present invention (a),
(B).

FIG. 18 is a side view showing one embodiment of the method for manufacturing a piezoelectric / electrostrictive device of the present invention.

19 (a), (b), (c), and (c) show a first embodiment of a method for manufacturing a piezoelectric / electrostrictive device according to the present invention.
(D).

FIG. 20 is a schematic explanatory view showing one embodiment of the optical shutter of the present invention, wherein (a) is a perspective view and (b) is a top view.

21 is a schematic explanatory view showing another embodiment of the optical shutter of the present invention, wherein (a) is a perspective view, (b) is a top view, and (c) is an enlarged view of a shielding plate.

[Explanation of symbols]

1. Piezoelectric / electrostrictive device, 2. Piezoelectric element, 3. Drive unit,
4 movable part, 5 fixed part, 6 thin plate, 8 hole, 21
Piezoelectric actuator, 22: electrode layer, 24: movable part, 2
Reference numeral 5: fixed portion, 26: beam portion, 28: hole portion, 31: piezoelectric / electrostrictive device, 32: piezoelectric element, 33: drive portion, 34: movable portion, 35: fixed portion, 36: thin plate, 38: hole Part, 41 ...
Piezoelectric / electrostrictive device, 42: piezoelectric element, 43: drive unit,
44 movable part, 45 fixed part, 46 thin plate, 48 hole, 49 slit, 51 piezoelectric / electrostrictive device, 52
... Piezoelectric element, 53 ... Drive section, 54 ... Movable section, 55 ... Fixed section, 56 ... Thin plate, 58 ... Hole section, 61 ... Piezoelectric / electrostrictive device, 62 ... Piezoelectric element (62a ... Piezoelectric film, 62b ... Top electrode) , 62c: lower electrode), 66, 67: thin plate, 68: hole, 72: piezoelectric element (72a: piezoelectric film, 72b: first electrode, 72c: second electrode), 73: gap, 76: thin plate,
82: piezoelectric element (82a: piezoelectric film, 82b: first electrode,
82c: second electrode), 86: thin plate, 91: piezoelectric / electrostrictive device, 92: piezoelectric element (92a: piezoelectric film, 92b: upper electrode, 92c: lower electrode), 93: drive unit, 94: movable unit, 95: fixed part, 96: thin plate, 98: hole, 10
1, 102: green sheet, 103: hole, 104:
Reference hole, 105: laminated body divided into two, 106: communication hole,
107: piezoelectric element, 108: laminated body, 110: optical shutter, 111A, 111B: unit, 112A, 11
2B: piezoelectric element, 113A, 113B: shielding plate, 114
A, 114B: movable part, 120: optical shutter, 121
A, 121B ... unit, 122A, 122B ... piezoelectric element, 123A, 123B ... shielding plate, 124A, 124B
... movable parts, 125A, 125B ... slits.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Koji Kimura Inventor F-term (reference) 2H041 AA02 AA04 AA06 AB03 AB04 AC08 AZ02 AZ05 AZ08 No. 2-56 Suda-cho, Mizuho-ku, Nagoya-shi, Aichi Japan

Claims (16)

[Claims] A driving unit that is driven by displacement of a piezoelectric / electrostrictive element, a movable unit that operates based on the driving of the driving unit, and a fixed unit that supports the driving unit and the movable unit. A piezoelectric / electrostrictive device, comprising: a driving unit including opposing thin plates and a thin-film piezoelectric / electrostrictive element formed on a surface of at least one of the thin plates; A piezoelectric / electrostrictive device, wherein a part and the movable part are connected. 2. The piezoelectric device according to claim 1, wherein the movable portion and the fixed portion have a rectangular parallelepiped shape, and opposed thin plates are straddled so that side surfaces of the movable portion and the fixed portion are continuous. Electrostrictive device. 3. The piezoelectric / electrostrictive device according to claim 1, wherein the driving unit is driven in a direction orthogonal to a displacement direction of the piezoelectric / electrostrictive element. 4. The piezoelectric / electrostrictive device according to claim 3, wherein the movable section operates in a plane including the driving direction of the driving section. 5. The piezoelectric / electrostrictive device according to claim 1, wherein the driving unit is used for detecting a displacement of the movable unit. 6. The piezoelectric / electrostrictive device according to claim 1, comprising at least two or more driving units. 7. The piezoelectric / electrostrictive device according to claim 1, wherein the width of the thin plate is at least five times the thickness of the thin plate. 8. The piezoelectric / electrostrictive element according to claim 1, wherein the piezoelectric / electrostrictive element is a laminated piezoelectric / electrostrictive element in which a lower electrode, a piezoelectric / electrostrictive film, and an upper electrode are stacked. Piezoelectric and electrostrictive devices. 9. The piezoelectric / electrostrictive element comprises a piezoelectric / electrostrictive film, a first electrode and a second electrode having a comb-shaped structure, and the first electrode and the second electrode are connected to each other by teeth of a comb. The piezoelectric / electrostrictive device according to any one of claims 1 to 8, wherein the piezoelectric / electrostrictive element is a piezoelectric / electrostrictive element having a structure in which the portions engage with each other with a gap having a fixed width between the portions. 10. The piezoelectric / electrostrictive device according to claim 1, wherein the movable portion, the thin plate, and the fixed portion are made of integrally formed ceramic. 11. The piezoelectric / electrostrictive device according to claim 10, wherein the movable portion, the thin plate, and the fixed portion are made of completely stabilized zirconia or partially stabilized zirconia. 12. The apparatus according to claim 10, wherein at least the movable part, the thin plate, and the fixed part are formed of a green sheet laminate.
The piezoelectric / electrostrictive device according to 1. 13. The piezoelectric / electrostrictive film constituting the piezoelectric / electrostrictive element is made of a material containing lead zirconate, lead titanate, and lead magnesium niobate as main components. Item 13. The piezoelectric / electrostrictive device according to item 1. 14. The piezoelectric / electrostrictive film according to claim 1, wherein the piezoelectric / electrostrictive film constituting the piezoelectric / electrostrictive element is made of a material containing sodium bismuth titanate as a main component.
Electrostrictive device. 15. A driving unit comprising a thin plate facing each other, a thin film piezoelectric / electrostrictive element formed on a surface of at least one of the thin plates, and a rectangular parallelepiped fixed unit and a movable unit. A method of manufacturing a piezoelectric / electrostrictive device in which opposing thin plates are straddled so that side surfaces of the movable portion and the fixed portion are continuous, wherein the green sheet to be the thin plate has a rectangular shape. A step of laminating at least one or more green sheets having one or more rows of holes and each of the green sheets to be the thin plate to obtain an integrated laminate, and a green sheet to be the thin plate by a thick film method or a thin film method Forming a piezoelectric / electrostrictive element on the surface of the laminate, and cutting the laminate in the green sheet laminating direction such that the rectangular holes are opened on the side surfaces of the laminate after firing the laminate. With pressure · Electrostrictive device manufacturing method. 16. An optical shutter for controlling transmission and shielding of light by relatively moving two shielding plates, wherein at least one of the shielding plates is one of any one of claims 1 to 14. An optical shutter, wherein the optical shutter is attached to a movable part of the piezoelectric / electrostrictive device according to item 1.