JPH1126832A - Piezoelectric film type element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly functional element which has a small size and can be driven with a low voltage by integrally constituting a piezoelectric layer carrying a flat film-like electrode on one surface and a plurality of belt-like electrodes on the other surface on a ceramic substrate. SOLUTION: In a piezoelectric film type element, a piezoelectric actuating layer is formed by successively and integrally laminating a single flat film-like lower electrode 6, a piezoelectric layer 8, and an upper electrode 10 composed of a plurality of belt-like electrodes 10a and 10b upon another on the external surface of a thin section 2a which functions as a diaphragm of a ceramic substrate 2. When an electric field is impressed between the electrodes 10a and 10b by conducting the electrodes 10a and 10b so that the electrodes 10a and 10b may alternately become positive and negative poles, the thin section 2a is displaced in the direction shown by the arrow due to the vertical effect of a field-induced strain caused by a piezoelectric effect. When, in addition, an electric field is impressed between the upper and lower electrodes 10 and 6 by conducting all of the belt-like electrodes 10a and 10b in the same polarity, the thin section 2b is displaced in the direction opposite to the arrow due to the horizontal effect of a field-induced strain. Therefore, two piezoelectric operations of the element can be made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a piezoelectric film element, and more particularly, to converting electric energy into mechanical energy, that is, converting mechanical energy into mechanical displacement, force or vibration.
The present invention relates to a structure that can improve the operation characteristics of an element that performs the reverse conversion.

[0002]

2. Description of the Related Art In recent years, in the fields of optics and precision machining, a displacement element for adjusting an optical path length and a position on the order of submicrons and a detection element for detecting a minute displacement as an electrical change have been desired. Is coming.

[0003] In response to this, an actuator utilizing the development of displacement based on the inverse piezoelectric effect which occurs when an electric field is applied to a piezoelectric material such as a ferroelectric substance, and a sensor utilizing the opposite phenomenon (piezoelectric effect). The development of a piezoelectric / electrostrictive element used for such purposes is underway.

[0004] Among them, in a speaker or the like, a conventionally known unimorph type or the like is suitably used as such a piezoelectric / electrostrictive element structure.

[0005] For this reason, even the applicant of the present application, first,
JP-A-3-128681 and JP-A-5-49270
In the gazette, it can be suitably used for various applications,
A piezoelectric (/ electrostrictive) film type element made of a ceramic material was proposed.

[0006] In the piezoelectric film type element proposed above, at least one thin diaphragm portion is integrally provided so as to cover at least one window portion (space).
A ceramic substrate on which two thin wall portions are formed, and a film-shaped piezoelectric actuation layer comprising a combination of a lower electrode, a piezoelectric layer, and an upper electrode on the outer surface of a diaphragm portion of the ceramic substrate. Have a structure integrally laminated.

This piezoelectric film type element utilizes a transverse effect of the piezoelectric effect (particularly, electric field-induced distortion), that is, a distortion in a direction orthogonal to the direction of the electric field, by applying an electric current between the upper electrode and the lower electrode. It is operated to generate a displacement, a force, a vibration, and the like.

This piezoelectric film type element is a small, inexpensive, highly reliable electromechanical conversion element, can obtain a large displacement at a low driving voltage, has a high response speed, and has a large generating force. It has excellent features and is recognized to be useful as a constituent member of actuators, filters, displays, sensors, and the like.

On the other hand, US Pat. No. 2,540,194 discloses that a strip-shaped electrode extending in the width direction of a piezoelectric layer is provided on a surface of a long plate-shaped piezoelectric layer having a predetermined thickness in the longitudinal direction of the piezoelectric layer. A piezoelectric actuator having a structure in which stripe-shaped piezoelectric actuators are provided at predetermined intervals is shown.

[0010] In this actuator, a predetermined electric field is applied between the strip electrodes by alternately applying different voltages to the strip electrodes arranged in a stripe as described above. Longitudinal effect of the piezoelectric effect (electric field induced strain) in the piezoelectric layer portion
Utilizing the effect of the direction parallel to the direction of the electric field, displacement, force, vibration, and the like are developed, or the reverse conversion is performed.

[0011]

However, in these conventional piezoelectric elements or piezoelectric film type elements, any of the conventional piezoelectric element and the piezoelectric film type element has a piezoelectric operation layer composed of a piezoelectric layer and two electrodes provided on both sides in the thickness direction thereof. Lateral effect of the piezoelectric effect (effect in the direction orthogonal to the direction of the electric field) or longitudinal effect of the piezoelectric effect in the piezoelectric working layer consisting of the piezoelectric layer and the strip electrode provided on one side (parallel to the direction of the electric field) Direction effect)
Only one of them was used. It is extremely effective to sufficiently exhibit and improve the operation characteristics of the piezoelectric operation layer of such an element in terms of miniaturization of the element and enhancement of the element function.

Further, in the drawing (FIG. 14) of the above-mentioned Japanese Patent Application Laid-Open No. 5-49270, a band-shaped electrode and a piezoelectric layer are successively and integrally formed on a ceramic substrate to form one piezoelectric operating layer (driving unit). Portion), and further, a film-shaped electrode, a piezoelectric layer, and a film-shaped electrode are sequentially formed thereon, and further another piezoelectric operation layer (drive portion) is integrally formed. The actuator has been revealed.

[0013] However, here, the structure is merely a structure in which two piezoelectric operation layers (driving units) are simply overlapped and laminated and integrated, so that two piezoelectric layers are inevitably required. Of course, it is unavoidable that the overall thickness of the piezoelectric operation layer is significantly increased. In addition, when one of the piezoelectric operation layers is operated, the operation of the other piezoelectric operation layer is restricted or hindered by the presence of the other piezoelectric operation layer, so that it is difficult to sufficiently exert the operation characteristics of each of the piezoelectric operation layers. The problem is inherent.

Here, the present invention has been made in view of such circumstances, and an object to be solved is to make full use of the operation characteristics of the piezoelectric operation layer, to reduce the size, Another object of the present invention is to provide a high-performance piezoelectric film element that can be driven at a low voltage.

[0015]

According to the present invention, there is provided a piezoelectric film type element comprising: a ceramic substrate; and a ceramic substrate provided on at least a portion of at least one surface of the ceramic substrate.
One piezoelectric layer, and a film-shaped piezoelectric operation layer composed of first and second electrodes integrally disposed on both sides in the thickness direction of the piezoelectric layer, and another piezoelectric operation layer is provided on the piezoelectric operation layer. In a piezoelectric film type element having a structure in which an operation layer is not stacked, the first electrode is formed by a single flat film-shaped electrode layer, and the second electrode is formed by forming at least a part thereof into a plurality of pieces. A first piezoelectric actuating means formed of band electrodes and comprising the first and second electrodes and the piezoelectric layer; the plurality of band electrodes of the second electrode and the piezoelectric layer; And a second piezoelectric actuating means comprising:

In such a piezoelectric film type element according to the present invention, the first piezoelectric actuating means effectively exerts a lateral effect of the piezoelectric effect, and the second piezoelectric actuating means exerts a vertical effect of the piezoelectric effect. The effect is advantageously exhibited.

Therefore, when such an element is applied to, for example, an actuator or a vibrator, the electric field induced distortion caused by the application of an electric field between the electrodes (first electrode and second electrode) sandwiching the piezoelectric layer in the thickness direction. The displacement and vibration of the diaphragm are controlled by utilizing the lateral effect of the piezoelectric element and the longitudinal effect of electric field induced strain caused by the application of an electric field between a plurality of strip electrodes (second electrodes) sandwiching the piezoelectric layer in the plane direction. It is possible to obtain the ceramic substrate in both vertical directions. In addition, as the displacement amplitude and the vibration amplitude, a combination of a vertical effect and a horizontal effect can be used, and thereby significantly improved displacement characteristics and vibration characteristics can be obtained. In other words, it means that a displacement equivalent to that of the conventional element can be obtained at a lower driving voltage.

Even in a conventional piezoelectric film type element, that is, an element utilizing one piezoelectric effect in one piezoelectric layer, in order to increase displacement and vibration amplitude, the piezoelectric layer is turned in the direction opposite to the polarization direction of the piezoelectric layer. Attempts have been made to perform the same operation by displacing the ceramic substrate, which is a diaphragm, in the vertical direction by applying an electric field. However, the electric field in the direction opposite to the polarization direction is a polarization inversion electric field (critical electric field). Or coercive electric field), it was difficult not only to obtain sufficient displacement and generated force, but also because an electric field close to the polarization inversion electric field was applied, It was a technique that still had issues with stability.

However, the piezoelectric film type element according to the present invention is not limited in principle to the above-described domain-inverted electric field,
Since an electrode to which an electric field is applied is selected and energized and operated, a highly reliable and stable operation can be obtained.

In particular, in the present invention, a piezoelectric material having a polarization inversion electric field (coercive electric field) of 10 kV / cm or less,
It is desirable to form a piezoelectric layer, and in a piezoelectric layer made of such a piezoelectric material, the polarization can be relatively easily and instantaneously performed with the application of an electric field. It is possible to demonstrate. Further, if a piezoelectric material for forming the piezoelectric layer is selected, it is possible to omit the polarization treatment prior to use of the element. Of course, such an effect can be similarly applied to a sounding body, a display element, and the like in addition to the illustrated actuator and vibrator.

On the other hand, even when the structure of the piezoelectric film type element according to the present invention is applied to a filter or the like, the excitation unit and the reception unit can be configured by sharing one piezoelectric layer and selecting electrodes. Therefore, the structure is advantageous in reducing the size of the device. In addition, a transformer can be similarly configured and used.

As described above, by adopting the structure of the piezoelectric film type element according to the present invention, the characteristics of the piezoelectric layer, which is not used in the conventional element, are skillfully derived and compared with the conventional element having the same function. As a result, further miniaturization, lower power consumption, and higher functionality can be achieved.

According to a preferred embodiment of the piezoelectric film type device according to the present invention, the ceramic substrate is formed as a thin diaphragm portion, and the piezoelectric operation layer is integrally formed on an outer surface of the diaphragm portion. Will be adopted.

According to a preferred embodiment of the piezoelectric film type element according to the present invention, the ceramic substrate is provided with at least one cavity, and a wall portion for partitioning the cavity from the outside is provided. A structure in which the portion is formed as a thin diaphragm portion and the piezoelectric actuation layer is integrally formed on the outer surface of the diaphragm portion is adopted.

In the case of these preferred embodiments, two comb-shaped electrodes may be formed by connecting a plurality of strip-shaped electrodes at every other pair at both ends in the longitudinal direction thereof. . Further, it is preferable that the ceramic substrate is made of a completely stabilized or partially stabilized material mainly composed of zirconium oxide.

In the above structure, the piezoelectric layer has a thickness of 1 to obtain a large displacement at a relatively low operating voltage.
It is desirable that the thickness be not more than 00 μm. Note that the thickness of the piezoelectric operation layer is preferably 150 μm or less.

In the case where the second piezoelectric actuating means is operated, considering the electric field near the lower conductive film (first electrode) which is not used as an electrode, the thickness of the piezoelectric layer is X, Assuming that the distance between the strip electrodes is Y, it is preferable that 0.3 ≦ X / Y ≦ 6 is satisfied.

In the above structure, the thickness of the diaphragm is preferably 50 μm or less in order to obtain a high-speed response and a large displacement of the piezoelectric film element. Furthermore, in order to improve the operation characteristics of the piezoelectric operation layer and obtain a large displacement and a large generated force by using, for example, an actuator as a detection unit, the average particle diameter of at least the crystal constituting the diaphragm portion of the ceramic substrate is reduced to 0. .1 to 2
μm is desirable.

Unless otherwise specified, the piezoelectric effect used in the present invention includes not only the piezoelectric effect but also the inverse piezoelectric effect and the electrostrictive effect. Needless to say, the piezoelectric actuation means includes the electrostriction actuation means.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the present invention comprises a combination of one type of piezoelectric layer formed on a ceramic substrate and two types of different electrodes (first and second electrodes).
By making use of both the respective actions or properties embodied by different electric fields on one piezoelectric layer,
The operation characteristics are improved or the functions are enhanced.

Hereinafter, an embodiment in which the piezoelectric film type element according to the present invention is applied as, for example, a displacement element (hereinafter, simply referred to as a piezoelectric film type element according to this embodiment) will be described with reference to FIGS. I will explain it.

The piezoelectric film type device according to the present embodiment is similar to that shown in FIG.
1A, a ceramic substrate 2 is provided. The ceramic substrate 2 has a space 4 therein.
The thin portion of the ceramic substrate 2 that constitutes the wall that separates from the outside is a thin portion 2a that functions as a diaphragm. On the outer surface of the thin portion 2a, the lower electrode 6, the piezoelectric layer 8, and the upper electrode 10 are sequentially and integrally laminated to form a film-shaped piezoelectric operation layer. The lower electrode 6 is formed in a single flat film shape, and the upper electrode 10 is composed of a plurality of strip electrodes 10a and 10b. Therefore, here, the lower electrode 6 corresponds to the first electrode, and the upper electrode 10 corresponds to the second electrode.

The piezoelectric film type device according to the present embodiment is shown in FIG.
As shown in FIG. 2B, a current is applied so that the plurality of strip electrodes 10a and 10b constituting the upper electrode 10 become alternately positive and negative poles, and a predetermined electric field is applied between the plurality of strip electrodes 10a and 10b. Then, the thin portion 2a is moved in one direction (the strip-shaped electrode 1) by the piezoelectric effect, here, the longitudinal effect of the electric field induced strain.
0a and 10b are displaced in the direction facing the free space (see the arrow in FIG. 1B). FIG. 2A shows the relationship between the displacement due to the longitudinal effect and the electric field.

On the other hand, as shown in FIG.
When all of the strip electrodes 10a and 10b (or selected ones thereof) have the same polarity and an electric field is applied between the upper electrode 10 and the lower electrode 6, a piezoelectric effect, here a transverse effect of electric field induced strain, The blank portion 2a is displaced in the other direction (the direction opposite to the direction in which the strip electrodes 10a and 10b face free space: see the arrow in FIG. 1C). FIG. 2B shows the relationship between the displacement and the electric field.

As described above, in the case of FIG. 1C, the first piezoelectric actuator is constituted by the lower electrode 6, the piezoelectric layer 8, and the upper electrode 10, and in the case of FIG. The second piezoelectric actuation means is constituted by the strip electrodes 10a and 10b and the piezoelectric layer 8.

Therefore, by controlling the energization or the voltage application to the upper electrode 10 and the lower electrode 6 at a predetermined timing, one piezoelectric layer 8 can arbitrarily change in one direction or the other direction. Displacement and force can be generated. That is, in a region where the displacements shown in FIGS. 2A and 2B are combined, a displacement, a force, and the like can be expressed. This is an effect that cannot be obtained with the conventional piezoelectric film type device.

Further, when a piezoelectric material is used for the displacement region a in FIG. 2C, a residual strain is generated by the polarization action. Therefore, by performing switching and rotating the polarization direction by 90 °, the residual distortion is regarded as a displacement. It can be used. As described above, by using both displacement, force, and vibration due to the longitudinal effect and displacement, force, and vibration due to the lateral effect in one piezoelectric layer 8,
For example, the displacement is obtained by combining the displacement due to the longitudinal effect and the displacement due to the lateral effect, and the characteristics are dramatically improved compared to the conventional case where only either the longitudinal effect or the lateral effect is used. Can be obtained. In addition, by using the displacement region a from the viewpoint of maintaining the displacement state, the piezoelectric film element according to the present embodiment can be configured as a memory.

Next, some examples (examples) of typical structures of the piezoelectric film type element according to the present embodiment will be described with reference to FIGS. In each of the embodiments shown in FIG. 3A and subsequent figures, the thickness, length, width, and the like are emphasized to facilitate understanding of the laminated structure of each layer, and correspond to actual dimensions. It should be understood that they have not.

First, as shown in FIG. 1A, the piezoelectric film type element according to the first embodiment shown in FIG. 3A is placed on one surface of a ceramic substrate 12 having a predetermined width in the form of a long flat plate. One flat film-like lower electrode 16, a single flat film-like piezoelectric layer 18, and a film-like upper electrode 20 composed of a plurality of band-like electrodes 20a and 20b are sequentially and integrally laminated to form a film-like It constitutes a piezoelectric working layer.

The ceramic substrate 12 has a space 1 therein.
The thin portion of the ceramic substrate 12 which forms a wall portion that partitions the space 14 from the outside is formed as a thin portion 12a serving as a diaphragm portion, and the thin portion 12a
Is formed integrally on the outer surface of the piezoelectric element. The lower electrode 16, the piezoelectric layer 18 and the upper electrode 20 extend over the thick portions 12 b, 12 b of the ceramic substrate 12 located on both sides of the cavity 14.
(Band electrodes 20a, 20b) are sequentially stacked.

The plurality of strip electrodes 20a and 20b constituting the upper electrode 20 are alternately arranged in stripes at predetermined intervals. On the upper electrode 20, no other piezoelectric layer, and thus no other piezoelectric operation layer, is laminated.

As described above, in the piezoelectric film type device according to the first embodiment shown in FIG.
And the upper electrode 20 constitutes a first piezoelectric actuating means utilizing the lateral effect of the piezoelectric effect, and utilizing the longitudinal effect of the piezoelectric effect from the plurality of strip electrodes 20a and 20b of the upper electrode 20 and the piezoelectric layer 18. A second piezoelectric actuating means is constructed.
Thus, by using one piezoelectric layer 18, two piezoelectric effects can be exhibited, and the characteristics of the piezoelectric film element can be improved.

Alternatively, as shown in FIG. 3B, the film-shaped piezoelectric actuator may be formed on a single plate-shaped ceramic substrate 12. In this case, by supporting the plate-shaped ceramic substrate 12 with a support member (not shown) provided separately, a function similar to that of the above-described diaphragm portion can be provided.

In the piezoelectric film element according to the second embodiment shown in FIGS. 4A and 4B, a plurality of strip electrodes 20a and 20b constituting the upper electrode 20 are formed at both ends in the longitudinal direction.
It is characterized in that every other pair is connected to each other to form two comb-shaped electrodes.

That is, every other strip electrode 20a
Are connected at the same end in the longitudinal direction to form a comb-shaped electrode, and the strip-shaped electrodes 20b alternately arranged with respect to the strip-shaped electrodes 20a are mutually connected at ends different from the strip-shaped electrodes 20a. Another one of the comb electrodes is formed by the connection. In particular, by adopting such a comb-shaped electrode structure, there is an advantage that power supply to a plurality of band-shaped electrodes 20a and a plurality of other band-shaped electrodes 20b is facilitated.

Further, in the piezoelectric film type device according to the third embodiment shown in FIGS. 5A and 5B, the piezoelectric layer 18 covers the lower electrode 16 provided on the long and thin ceramic substrate 12 in the width direction. And a band-shaped electrode 20 constituting the upper electrode 20 so as to cover the piezoelectric layer 18 in the width direction.
The feature is that a and 20b are provided respectively.

That is, the piezoelectric layer 18 is longer than the lower electrode 16 in the width direction of the ceramic
0 is provided to be longer than the piezoelectric layer 18.
In this case, even when the piezoelectric layer 18 and the upper electrode 20 (the strip electrodes 20a and 20b) are displaced from the lower electrode 16, short-circuiting of the electrodes 16 and 20 can be avoided.

In the piezoelectric film element according to the present embodiment, not only the element having the unimorph structure as described above, but also the element having the bimorph structure as shown in FIGS. 6A and 6B can be formed. .

That is, in the piezoelectric film type device according to the fourth embodiment shown in FIGS. 6A and 6B, a structure similar to that of the first embodiment (see FIGS. 3A and 3B) is formed on one surface of the ceramic substrate 12. One piezoelectric operation layer including the lower electrode 16, the piezoelectric layer 18, and the upper electrode 20 (strip electrodes 20a, 20b) is provided integrally, and the other surface of the ceramic substrate 12 has the same structure as the piezoelectric operation layer. Structure lower electrode 116, piezoelectric layer 11
8 and upper electrode 120 (strip electrodes 120a, 120b)
Another piezoelectric actuation layer made of is integrally provided.

In such a bimorph type piezoelectric film type element, the operation mode of the two piezoelectric operation means in each piezoelectric operation layer is controlled. For example, when the piezoelectric element is used as a displacement element, The piezoelectric operation layers on both sides of the ceramic substrate 12 are controlled so as to apply displacement, force or vibration in the same direction.

The piezoelectric film element according to the fifth embodiment shown in FIG. 7 is characterized in that the ceramic substrate 12 has a cavity structure. That is, the ceramic substrate 12 has a space 14 therein.
The thin portion of the ceramic substrate 12 that constitutes the wall portion that partitions the outside from the outside is formed as a thin portion 12a that becomes a diaphragm portion, and a film-like piezoelectric material similar to the example of FIGS. 3A and 3B is formed on the outer surface of the thin portion 12a. The working layer is formed integrally.
The lower electrode 16, the piezoelectric layer 18, and the upper electrode 20 (the strip electrodes 20a, 20b) extend over the thick portions 12b, 12b of the ceramic substrate 12 located on both sides of the cavity 14. ) Are sequentially laminated and integrated to form a so-called doubly supported beam structure.

The piezoelectric film type device according to the sixth embodiment shown in FIG. 8 has a thin portion 12a formed at the center in the width direction and thick portions 12b, 1
2b, a ceramic substrate 12 having a cavity structure is used. On the thin portion 12a of the ceramic substrate 12, two piezoelectric operation layers are provided, each end of which has a thick portion 12a.
b so as to be integrally provided.

That is, each piezoelectric operation layer is formed on the ceramic substrate 1.
In a mode in which the lower electrode 16, the piezoelectric layer 18, and the upper electrode 20
(Band electrodes 20a, 20b) are sequentially laminated and integrated.

The piezoelectric film type device according to the sixth embodiment is
Unlike the piezoelectric film type device according to another embodiment, the upper electrode 2
A plurality of band-like electrodes 20a and 20b constituting 0
When a predetermined electric field is applied between the plurality of band-shaped electrodes 20a and 20b by applying a current so as to be a pole and a negative pole, the thin portion 12a is moved in the other direction (the band-shaped electrodes 20a and 20b) due to the longitudinal effect of electric field-induced strain. In the direction opposite to the direction facing the free space).

The upper electrode 20 (all of the strip electrodes 20a and 20b or a selected one thereof) has the same polarity,
When an electric field is applied between the upper electrode 20 and the lower electrode 16, the thin portion 12a is moved in one direction (the direction in which the strip electrodes 20a and 20b face free space) due to the transverse effect of electric field induced strain.
Is displaced.

In the piezoelectric film type element according to the seventh embodiment shown in FIGS. 9 and 10A and 10B, as is apparent from the figure, three voids 14 are formed inside the ceramic substrate 12, and The cavities 14 are respectively connected to the outside through the communication openings 22. In addition, the empty space 1
On the outer surface of the thin portion 12a of the ceramic substrate 12 formed by the step 4, a film-shaped piezoelectric operation layer having a configuration as shown in FIGS. 4A and 4B is integrally formed.

That is, the piezoelectric operating layer has a monolithic structure in which the lower electrode 16, the piezoelectric layer 18, and the upper electrode 20 are sequentially laminated to form an integrated structure.
a and 20b are formed as comb-shaped electrodes as in the example of FIGS. 4A and 4B, respectively.

In addition, as shown in FIGS. 11A and 11B, the film-shaped piezoelectric actuator may be formed on a single plate-shaped ceramic substrate 12. In this case, by supporting the plate-shaped ceramic substrate 12 with a support member (not shown) provided separately, a function similar to that of the above-described diaphragm portion can be provided.

In FIG. 10A and FIG. 11A, the piezoelectric actuator is 3
There are four or more depending on the purpose.

In the piezoelectric film type element according to the present embodiment, the upper electrode 20 composed of the plurality of strip electrodes 20a and 20b is provided in the above-described example in the form of a stripe having the same size. However, the width of the strip electrodes 20a and 20b can be appropriately selected. For example, as shown in FIGS.
It is also possible to make the width of the strip electrode 20b wider than the width of the strip electrode 20a by alternately changing the width of the strip electrodes 20a and 20b. It is possible to easily adjust the conversion amount.

As shown in FIGS. 13A and 13B, the piezoelectric film type element according to the present embodiment is configured such that the upper electrode 20 is composed of two spiral strip electrodes 20a and 20b, respectively, and the center of the spiral is formed. It is also possible to adopt a structure in which one strip-shaped electrode 20a and the other strip-shaped electrode 20b are arranged so as to be arranged alternately from the outside toward the radial direction.

Further, in the piezoelectric film type device according to the present embodiment, as shown in FIGS. 14A and 14B, a predetermined portion of the upper electrode 20 is constituted by a plurality of strip electrodes 20a and 20b. A film-shaped piezoelectric operation layer having a configuration in which a portion is a single flat film-shaped electrode portion 20 c may be provided integrally on the ceramic substrate 12. FIG. 14A,
In the example shown in B, the strip electrodes 20a and 20b are each formed as a comb-shaped electrode. By adopting such a structure of the upper electrode 20, for example, when used as an actuator or a vibrator, the displacement and the generated force due to the lateral effect of the electric field induced strain, and the displacement and the generated force due to the vertical effect. There is an advantage that the balance can be easily adjusted.

As described above, the piezoelectric film type device according to the present embodiment can be embodied in various forms. In addition to the above-described examples, the piezoelectric film type device may be embodied without departing from the spirit of the present invention. It should be understood that various changes, modifications, improvements, and the like can be made, all of which are included in the scope of the present invention.

For example, in the specific example of the above-described example, a space is formed between the plurality of strip electrodes 20a and 20b constituting the upper electrode 20, and a piezoelectric material for providing the piezoelectric layer 18 is formed between the strip electrodes 20a and 20b. It does not matter what kind of filling is performed, and the lower electrode 16 and the upper electrode 20 may have a reversed structure. It is also possible to form the upper electrode 20 as a single flat film-shaped electrode layer and to form at least a part of the lower electrode 16 with a plurality of strip electrodes. In this case, the upper electrode 20 composed of a single flat film-shaped electrode layer corresponds to the first electrode, and the lower electrode 16 composed of a plurality of band-shaped electrodes corresponds to the second electrode.

The piezoelectric film type device according to the present embodiment is specifically manufactured as follows.

First, the material for forming the ceramic substrates (2, 12) constituting the piezoelectric film type element according to the present embodiment has a large mechanical strength, and is 1400 as described later.
It is possible to adopt an insulator or a dielectric that can be heat-treated at about ° C. and that can be laminated and integrated with the piezoelectric operation layer without using an adhesive or the like. Even if it is a non-oxide type ceramic material, it does not matter at all.

Among the materials having the above-described conditions, aluminum oxide, magnesium oxide, zirconium oxide, aluminum nitride, and silicon nitride are among the materials having the above-described conditions in order to obtain excellent operation characteristics of large displacement and generated force and high response speed. A material containing at least one as a main component is suitably employed. In particular, the use of ceramic materials based on aluminum oxide and / or zirconium oxide is recommended. Furthermore, among them, in particular, yttrium oxide,
A material based on zirconium oxide, which is completely or partially stabilized with at least one compound of ytterbium oxide, cerium oxide, calcium oxide and magnesium oxide, can be advantageously used. The reason is that high mechanical strength can be obtained even at a thin substrate thickness, high toughness, low stress during heat treatment with the piezoelectric material used in the film forming method, and chemical reactivity with the piezoelectric material. Is small.

Further, the amount of addition of the above-mentioned compound for stabilizing zirconium oxide is 1 mol% to 30 mol% for yttrium oxide or ytterbium oxide, 6 mol% to 40 mol% for cerium oxide, calcium oxide or In the case of magnesium oxide, the content is preferably 5 mol% to 40 mol%. Among them, it is particularly desirable to use yttrium oxide as a stabilizer. In this case, the amount of addition is preferably 1.5 mol% or more and 6 mol% or less, more preferably 2 mol% or more and 4 mol% or less. It is desirable to do. In such an addition range, the crystal phase of zirconium oxide to which yttrium oxide is added is partially stabilized, so that a substrate having excellent substrate characteristics can be realized.

Further, a sintering aid such as aluminum oxide, titanium oxide, or clay may be added to the stabilized zirconium oxide. In this case, it is desirable to adjust the composition and amount of the auxiliary agent so that the baked substrate does not contain silicon oxide (SiO ₂ , SiO) in an amount of 1% or more. This is because, when excessive silicon oxide is contained in the substrate, a reaction is likely to be caused at the time of heat treatment with the piezoelectric material, and it becomes difficult to control the composition.

The ceramic substrate (2, 12)
Is finally in a sintered form, but before sintering the ceramic substrate (2, 12), prior to forming the piezoelectric operation layer of the piezoelectric film type element according to the present embodiment, A method of forming a substrate by sintering, or a method of using a green sheet of a substrate material, forming a piezoelectric operation layer by forming a film described later, and then sintering the film can be used.
Among them, the method in which the ceramic substrate (2, 12) is sintered in advance to form the substrate is advantageously used because the warpage of the element can be reduced and the required pattern dimensional accuracy can be obtained. Can be

The ceramic substrates (2, 12) having a cavity structure as shown in FIGS.
A thin green sheet for providing a thin portion (2a, 12a) to a green sheet provided with a hole for forming the space (4, 14) by using a mold or a machining method such as ultrasonic processing. Are laminated, thermocompression bonded, and then integrated by firing, which is suitably adopted from the viewpoint of high reliability.

Further, in the ceramic substrate (2, 12), at least a part of the portion where the piezoelectric operation layer of the piezoelectric film type element according to the present embodiment is formed is a thin portion (2a, 12a). It is desirable. The thickness is generally 50 μm in order to obtain high-speed response and large displacement of the piezoelectric film element.
m, preferably 30 μm or less, more preferably 15 μm or less.
It is desirable that the thickness be not more than μm.

The thin portions (2a, 12a) generally improve the operating characteristics of the piezoelectric operating layer provided thereon, and, for example, in order to obtain a large displacement, a large generated force, etc. Has an average particle size of 0.1
The average particle diameter is desirably set to be 2 μm or less, more preferably, 1 μm or less.

In the case of a single plate-like ceramic substrate 12 as shown in FIG. 3B or FIG. 4B, the thickness of the ceramic substrate 12 is set so as to obtain the high-speed response and large displacement of the piezoelectric film type element. In general, the thickness is desirably 50 μm or less, preferably 30 μm or less, and more preferably 15 μm or less.

Further, at least a portion of the ceramic substrate 12 where the piezoelectric actuation layer is formed is intended to enhance the operation characteristics of the piezoelectric actuation layer and to obtain a large displacement, a large generated force, etc., for example, as an actuator or a detecting portion. Generally, it is desirable that the average particle size of the crystal be 0.1 to 2 μm, more preferably, the average particle size is 1 μm or less.

Then, as in the piezoelectric film type device according to the present embodiment, a predetermined lower electrode 16, a piezoelectric layer 18, and an upper electrode 20 are provided on at least one surface of the ceramic substrate (2, 12). In order to form a piezoelectric working layer,
Various film formation techniques are appropriately adopted. For example, a method of forming a thick film such as screen printing, spraying, dipping, or coating, or a method of forming a thin film such as ion beam, sputtering, vacuum evaporation, ion plating, CVD, or plating is appropriately selected.

In particular, when the piezoelectric layer 18 is formed, a method of forming a thick film by screen printing, spraying, dipping, coating or the like is suitably adopted. According to these methods of forming a thick film, a film or a film is formed on a ceramic substrate using a paste or a slurry mainly composed of ceramic particles of a piezoelectric material having an average particle diameter of 0.01 μm to 5 μm, preferably 0.05 μm to 3 μm. And good element characteristics can be obtained.

In order to form the film into a desired shape, in addition to a method of forming a pattern using a screen printing method, a photolithography method or the like, a laser processing method such as excimer or YAG, slicing, ultrasonic processing, or the like. A technique such as forming a pattern by removing unnecessary portions using a machining method is employed. As a result, desired shapes of the lower electrode 16, the piezoelectric layer 18, and the upper electrode 20 are realized.

Further, these pattern formations can be performed before or after a heat treatment described later, but are preferably performed before the heat treatment in view of ease of pattern formation and pattern accuracy.

The structure of the element manufactured here and the shape of the film-shaped piezoelectric operation layer are not limited at all.
Any shape can be adopted depending on the application, for example, a triangle, a polygon such as a square, a circle such as a circle, an ellipse, a ring, a comb, a lattice, or a special shape obtained by combining these. No problem.

Each of the films (6, 8, 10; 16, 18, 20) thus formed on the ceramic substrate (2, 12) by the above-described method is used for forming the respective films. Each time, heat treatment may be performed to form an integral structure with the substrate. Alternatively, after all films are formed, heat treatment may be performed at the same time so that each film is simultaneously bonded to the substrate. .

When an electrode film is formed by such a film forming method, heat treatment may not always be required for integration. For example, before forming the upper electrode film (10, 20), the lower electrode film (6, 1) is formed.
In order to ensure insulation with 6), an insulating coating may be applied around the element with an insulating resin or the like.
For the formation of the upper electrode films (10, 20), methods such as vapor deposition, sputtering, and plating that do not require heat treatment are employed.

As a heat treatment temperature for integrating each film thus formed and the ceramic substrate, a temperature of about 900 ° C. to 1400 ° C. is generally adopted, and preferably in a range of 1000 ° C. to 1400 ° C. Is advantageously selected. When the piezoelectric layers (8, 18) are heat-treated, it is preferable to perform the heat treatment while controlling the atmosphere together with the evaporation source of the piezoelectric material so that the composition of the piezoelectric layers does not become unstable at high temperatures.

It is also recommended to adopt a method in which an appropriate cover member is placed on the piezoelectric layers (8, 18) and firing is performed so that the surface is not directly exposed to the firing atmosphere. In this case, a material similar to the substrate (for example, a material containing aluminum oxide, zirconium oxide, or magnesium oxide as a main component) is used as the cover member. Further, with respect to a baking table (setter) used in baking, so as not to affect the baking atmosphere of the piezoelectric layer, for example, like the cover member,
It is preferable to use a material mainly containing aluminum oxide, zirconium oxide, or magnesium oxide.

By the way, the material of the lower electrode films (6, 16) constituting the above-mentioned piezoelectric operation layer is not particularly limited as long as it is a conductor which can withstand the high temperature oxidizing atmosphere of the heat treatment temperature and the baking temperature. For example, it may be a simple metal or an alloy, a mixture of an insulating ceramic and a metal or an alloy, or a conductive ceramic.

More preferably, high melting point noble metals such as platinum, palladium and rhodium, or silver-palladium and silver-
Platinum, an electrode material mainly containing an alloy such as platinum-palladium, a cermet material of platinum and a ceramic substrate material, a cermet material of platinum and a piezoelectric material, and a cermet material of platinum, a substrate material, and a piezoelectric material are preferably used. Among them, a material containing platinum as a main component is more preferable.

When glass such as silicon oxide is used as a material to be added to the electrodes, a reaction easily occurs during heat treatment with the piezoelectric layers (8, 18), which tends to cause deterioration of element characteristics. It is desirable to avoid. It is preferable that the substrate material to be added to the electrode is about 5 to 30% by volume, and the piezoelectric material is about 5 to 20% by volume.

On the other hand, the material for forming the upper electrodes (10, 20) is not particularly limited. In addition to the above-mentioned electrode materials, a sputtered film of gold, chromium, copper, or the like, or gold or silver. Even if it is a resinate print film, there is no problem.

The electrode film formed using such a conductive material is generally 20 μm or less, preferably 5 μm or less.
μm or less, but in particular, the upper electrode film (1
0, 20), it is advantageously formed in a thickness of 1 μm or less, preferably 0.5 μm or less.

The piezoelectric film type element according to the present embodiment is a film comprising the lower electrodes (6, 16), the piezoelectric layers (8, 18), and the upper electrodes (10, 20) formed as described above. These lower electrodes (6, 16)
And at least a part of one of the upper electrodes (10, 20) is constituted by a plurality of strip-shaped electrodes to form a stripe shape.

Such a band-like electrode (in the illustrated specific example,
The distance between 10a and 10b; 20a and 20b) is appropriately selected and difficult to determine uniquely, but is generally 100 μm or less, preferably 50 μm or less, and particularly 20 μm or less. This is effective in obtaining a large displacement with a voltage.

Further, these strip electrodes (10a, 10b;
The pitch of 20a, 20b) is desirably 200 μm or less, particularly preferably 100 μm or less, in order to obtain a large displacement at a relatively low voltage.
μm or less is more desirable.

The piezoelectric material of the piezoelectric layers (8, 18) constituting the piezoelectric working layer of the piezoelectric film type element according to the present invention may be any material that exhibits a piezoelectric effect, in particular, an electric field induced strain. Even materials can be employed. For example, it may be a crystalline material, an amorphous material, a semiconductor material, a dielectric ceramic material or a ferroelectric ceramic material. The material may need to be polarized or may not be necessary. In particular, in the present embodiment,
A piezoelectric material that does not require a polarization treatment is advantageously used, and among materials that require a polarization treatment, a piezoelectric material whose polarization reversal electric field (coercive electric field) is 10 kV / cm or less is advantageously used. Thereby, the characteristics of the piezoelectric film element can be effectively extracted.

Specifically, the piezoelectric material used in the present invention is preferably a lead zirconate titanate (PZT).
Material), a material mainly containing lead titanate, a material mainly containing lead zirconate, a material mainly containing lead magnesium niobate (PMN-based), lead nickel niobate (PNN-based) material, lead magnesium tungstate material, lead manganese niobate material, lead antimonate stannate material, zinc zinc niobate Examples of the material include a material that is a component, a material that is mainly composed of lead magnesium tantalate, a material that is mainly composed of lead nickel tantalate, and a composite material thereof.

The above-mentioned materials include lanthanum, barium, niobium, zinc, cerium, cadmium, chromium, cobalt, antimony, iron, yttrium, tantalum, tungsten, nickel, manganese, lithium, strontium, magnesium, calcium, bismuth and the like. It does not matter what kind of oxide or other compound may be contained as an additive. For example, a PLZT-based material obtained by adding a lanthanum oxide or the like to a PZT-based material can be used. .

Of these piezoelectric materials, those having a coercive electric field of 10 kV / cm or less include PZT-based materials and
PMN system, mixed system of lead titanate and PMN, PLZT system,
PBZ in which barium is added to a material mainly composed of PZT
T-based, PZT-based ternary system (a material mainly composed of a component composed of lead magnesium niobate, lead zirconate and lead titanate, composed of lead nickel niobate, lead titanate and lead zirconate A material having a component as a main component) or the like is used after the components are adjusted.

Further, among them, PMN type, PMN
Mixed systems, PLZT systems, and PBZT systems are used as electrostrictive materials.
In particular, it can be used without performing a polarization treatment.

[0098] Among these piezoelectric materials, a material mainly composed of lead magnesium niobate, lead zirconate and lead titanate, or lead nickel niobate, lead magnesium niobate and lead zirconate is used. And a material mainly containing a component consisting of lead titanate, or a material mainly containing a component consisting of lead nickel tantalate, lead magnesium niobate, lead zirconate, and lead titanate, or lead magnesium tantalate. A material mainly containing a component composed of lead magnesium niobate, lead zirconate and lead titanate is preferable.

Further, among them, particularly, a material mainly containing a component composed of lead magnesium niobate, lead zirconate and lead titanate is advantageously used. Because
This is because the above-mentioned materials not only have a high piezoelectric constant, but also react less with the substrate material during the heat treatment.

That is, for example, the coupling state between the overhanging portion of the piezoelectric layer 18 and the ceramic substrate 12 as shown in FIGS. 5A and 5B is suppressed to such an extent that the performance required for the piezoelectric operation layer is not affected. In addition, segregation of components is not easily caused, treatment for maintaining the composition is easily performed, and the desired composition and crystal structure are easily obtained. Therefore, the above material is recommended as a material for forming the piezoelectric layer by a thick film forming technique such as screen printing, spraying, dipping, or coating.

In the case of a multi-component piezoelectric material, the piezoelectric properties change depending on the composition of the components. However, lead magnesium niobate-lead zirconate-titanium which is preferably employed in the piezoelectric film type element according to the present embodiment. In a ternary lead acid material, the composition near the phase boundary of pseudo-cubic-tetragonal-rhombohedral is preferable, and in particular, lead magnesium niobate: 15 mol% to 50 mol%, lead zirconate: 10 mol% to A composition of 45 mol% and lead titanate: 30 mol% to 45 mol% is advantageously employed because it has a high piezoelectric constant and an electromechanical coupling coefficient.

The thickness of the piezoelectric layers (8, 18) formed using such a piezoelectric material is generally 100 μm in order to obtain a large displacement at a relatively low operating voltage.
Or less, preferably 50 μm or less, more preferably 3 μm
It is desirable that the thickness be about 40 μm. Further, in addition to the piezoelectric layers (8, 18), the thickness of the film-shaped piezoelectric operating layer including the lower electrodes (6, 16) and the upper electrodes (10, 20) is generally 150 μm or less. , Preferably 50 μm or less.

More effectively, when the second piezoelectric actuating means is operated, a band-like shape is considered in consideration of the electric field near the lower conductive film (lower electrode) (6, 16) not used as an electrode. It is desirable that the ratio between the distance Y between the upper electrodes (see FIG. 1A) and the thickness X (see FIG. 1A) of the above-mentioned piezoelectric layers (8, 18) is appropriately adjusted. It is desirable that the ratio X / Y of the distance Y and the thickness X of the piezoelectric layer be in the following range.

0.3.ltoreq.X / Y.ltoreq.6 Also, it is desirable that the voltage signal applied to each piezoelectric actuating means is appropriately adjusted and driven according to the thickness of the piezoelectric layer 18 and the distance between electrodes.

In the piezoelectric film type device (using a ceramic substrate having a cavity structure) according to the above-described embodiment, a part of the
2, the film-shaped piezoelectric operating portion may be formed only on the thin portion 12a, as shown typically in FIG.

The piezoelectric film type element according to the present embodiment obtained as described above converts electric energy into mechanical energy, that is, converts it into mechanical displacement, force, vibration, or vice versa. Transducers, and various actuators, frequency domain functional components (filters), various display devices (displays),
Transformers, microphones, sound generators (speakers, etc.), transducers for communication and power, resonators, oscillators, discriminators, various sensors such as ultrasonic sensors, acceleration sensors, angular velocity sensors, impact sensors, gyros, and more Is used for servo displacement elements, pulse drive motors, ultrasonic motors, piezoelectric fans, piezoelectric relays, etc. described in "Piezoelectric / Electrostrictive Actuators from Basic to Applied" by Kenji Uchino (edited by Japan Industrial Technology Center). The present invention can be applied to a unimorph-type element and a bimorph-type element, and is preferably advantageously used for various actuators, vibrators, sound generators, display devices, and the like.

Further, since the piezoelectric film type element according to the present embodiment has not only piezoelectric characteristics (including electrostriction characteristics) but also dielectric properties, it can be used as a film-like capacitor element. If a material having ferroelectricity is used as the piezoelectric material, it can be used as an electron-emitting device.

As is apparent from the above description, according to the present invention, the first piezoelectric operating means and the second piezoelectric operating means are constituted by using one piezoelectric layer, and the two piezoelectric operating means are constituted. In the form in which the operation of (1) is combined, the entire operation of the piezoelectric film type element is exhibited, so that the piezoelectric effect is sufficiently utilized, and the piezoelectric film type element has The device characteristics are significantly improved. As a result, a high-performance piezoelectric film element that can be reduced in size and can be driven at a low voltage can be realized.

In particular, by using the piezoelectric film type element according to the present invention as a displacement element such as an actuator or a vibrator, the piezoelectric effect, in particular, the horizontal effect and the vertical effect of electric field induced strain are utilized to make the displacement. The amplitude, vibration amplitude, and force can be significantly increased, and dramatically improved displacement characteristics, vibration characteristics, and force characteristics can be realized.

Although the piezoelectric film element according to the present embodiment has been specifically described based on several examples, the present invention should not be construed as being limited to the above-described examples. It should be understood that various changes, modifications, improvements, and the like can be made based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0111]

As described above, the piezoelectric film type element according to the present invention comprises the first electrode, the second electrode and the piezoelectric layer to constitute the first piezoelectric actuation means, while the second electrode comprises the second electrode. The second piezoelectric actuation means is constituted by the electrode and the piezoelectric layer, that is, by taking an element structure in which two piezoelectric actuation means are constituted by using one piezoelectric layer, the operation characteristic of the piezoelectric actuation part is obtained. Therefore, it is possible to provide a high-performance piezoelectric film-type element that is reduced in size and can be driven at a low voltage.

[Brief description of the drawings]

FIG. 1A is a schematic cross-sectional view showing an embodiment (referred to as a piezoelectric film type element according to an embodiment) when a piezoelectric film type element according to the present invention is applied as a displacement element;
FIG. 1C is a schematic cross-sectional view showing a state in which a second piezoelectric actuator of the piezoelectric film element according to the present embodiment is operated.
5 is a schematic cross-sectional view showing a state in which first piezoelectric actuation means of the piezoelectric film type element according to the present embodiment is operated.

FIG. 2A is a graph showing a relationship between displacement and an electric field when a second piezoelectric actuator of the piezoelectric film type element according to the present embodiment is operated, and FIG. 2B is a graph showing the present embodiment; FIG. 2C is a graph showing the relationship between the displacement and the electric field when the first piezoelectric actuator of the piezoelectric film element according to the first embodiment is operated. FIG. 2C shows the first piezoelectric operation of the piezoelectric film element according to the present embodiment. 6 is a graph showing a relationship between displacement and an electric field in a state in which both the device and the second piezoelectric actuator are operated.

FIG. 3A is a partial perspective view showing a piezoelectric film element (using a ceramic substrate having a cavity structure) according to a first embodiment, and FIG. 3B is a piezoelectric film element according to the first embodiment. FIG. 3 is a partial perspective view showing an element (using one plate-shaped ceramic substrate).

FIG. 4A is a partial perspective view showing a piezoelectric film type device (using a ceramic substrate having a cavity structure) according to a second embodiment, and FIG. 4B is a piezoelectric film type device according to the second embodiment. FIG. 3 is a partial perspective view showing an element (using one plate-shaped ceramic substrate).

FIG. 5A is a partial perspective view showing a piezoelectric film type device (using a ceramic substrate having a cavity structure) according to a third embodiment, and FIG. 5B is a piezoelectric film type device according to the third embodiment. FIG. 3 is a partial perspective view showing an element (using one plate-shaped ceramic substrate).

FIG. 6A is a partial perspective view showing a piezoelectric film type device (a device having a bimorph type structure using a ceramic substrate having a cavity structure) according to a fourth example, and FIG. It is a partial perspective view showing such a piezoelectric film type element (element of a bimorph type structure using one plate-like ceramic substrate).

FIG. 7 is a partial perspective view showing a piezoelectric film type device (using a ceramic substrate having a cavity structure) according to a fifth embodiment.

FIG. 8 is a partial perspective view showing a piezoelectric film type device (using a ceramic substrate having a cavity structure) according to a sixth embodiment.

FIG. 9 is a perspective view showing a piezoelectric film type device according to a seventh embodiment.

FIG. 10A is a sectional view taken along the line AA of the piezoelectric film type element (using a ceramic substrate having three voids) shown in FIG. 9, and FIG. 10B is shown in FIG. It is BB sectional explanatory drawing of a piezoelectric film type | mold element (the thing using the ceramic substrate which has three vacancies).

FIG. 11A is a cross-sectional view of the piezoelectric film type element (using one plate-shaped ceramic substrate) AA shown in FIG. 9;
FIG. 11B is an explanatory cross-sectional view of the piezoelectric film element (using one plate-shaped ceramic substrate) shown in FIG. 9 along the line BB.

FIG. 12A is a partial perspective view showing another example of the piezoelectric film type device (using a ceramic substrate having a cavity structure) according to the present embodiment, and FIG. 12B is a partial perspective view of the present embodiment. FIG. 9 is a partial perspective view showing another example of such a piezoelectric film element (using one plate-shaped ceramic substrate).

FIG. 13A is a perspective view showing still another example of the piezoelectric film type element (using a ceramic substrate having a cavity structure) according to the present embodiment, and FIG. 13B is a perspective view showing the present embodiment. It is a perspective view which shows a further different example of a piezoelectric film type | mold element (one using one plate-shaped ceramic substrate).

FIG. 14A is a partial perspective view showing still another different example of the piezoelectric film element (using a ceramic substrate having a cavity structure) according to the present embodiment;
FIG. 9 is a partial perspective view showing still another different example of the piezoelectric film type device (using one plate-shaped ceramic substrate) according to the present embodiment.

FIG. 15 is a modified example of the piezoelectric film element according to the embodiment;
In particular, it is a cross-sectional view showing an example in which a film-shaped piezoelectric operating portion is formed only in a thin portion.

[Explanation of symbols]

2, 12: ceramic substrate 2a, 12a: thin portion 4, 14, vacant space 6, 16, 116
... lower electrodes 8, 18, 118 ... piezoelectric layers 10, 20, 12
0: Upper electrode 10a, 10b, 20a, 20b, 120a, 120b
... Strip electrode 12b ... Thick part 20c ... Electrode part

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02N 2/00 H01L 41/18 101D 41/22 Z

Claims (12)

[Claims] 1. A ceramic substrate, one piezoelectric layer provided in a layer on at least a part of at least one surface of the ceramic substrate, and first piezoelectric layers integrally provided on both sides in a thickness direction of the piezoelectric layer. And a film-shaped piezoelectric operation layer composed of a second electrode and a second electrode, and a piezoelectric film element having a structure in which another piezoelectric operation layer is not stacked on the piezoelectric operation layer. The second electrode is formed by a single flat film-like electrode layer, and at least a part of the second electrode is formed by a plurality of strip-shaped electrodes, and includes the first and second electrodes and the piezoelectric layer. A piezoelectric film element comprising: a first piezoelectric actuating means provided; and a second piezoelectric actuating means comprising the plurality of strip electrodes of the second electrode and the piezoelectric layer. 2. The piezoelectric film element according to claim 1, wherein said piezoelectric layer is formed of a piezoelectric material having a coercive electric field of 10 kV / cm or less. 3. The piezoelectric film type device according to claim 1, wherein the ceramic substrate is formed as a thin diaphragm portion, and the piezoelectric operation layer is integrally formed on an outer surface of the diaphragm portion. A piezoelectric film type element characterized by the above-mentioned. 4. The piezoelectric film type device according to claim 3, wherein the crystal constituting the ceramic substrate has an average particle diameter of 0.5.
A piezoelectric film element having a thickness of 1 to 2 μm. 5. The piezoelectric film-type element according to claim 1, wherein the ceramic substrate has at least one void, and the ceramic substrate portion that provides a wall that partitions the void from the outside is thin. A piezoelectric film type element formed as a diaphragm portion, wherein the piezoelectric operation layer is integrally formed on an outer surface of the diaphragm portion. 6. The piezoelectric film type device according to claim 5, wherein at least an average particle diameter of crystals constituting the diaphragm portion of the ceramic substrate is 0.1 to 2 μm. element. 7. The piezoelectric film type device according to claim 3, wherein said diaphragm has a thickness of 50 μm or less. 8. The piezoelectric film-type element according to claim 1, wherein the plurality of strip-shaped electrodes are connected to each other at every other end in the longitudinal direction. A piezoelectric film type element comprising two comb-shaped electrodes. 9. The piezoelectric film type element according to claim 1, wherein the ceramic substrate is made of a completely stabilized or partially stabilized material mainly composed of zirconium oxide. A piezoelectric film element. 10. The piezoelectric film type device according to claim 1, wherein said piezoelectric layer has a thickness of 100 μm or less. 11. The piezoelectric film type device according to claim 1, wherein said piezoelectric actuation layer has a thickness of 150 μm or less. 12. The piezoelectric film type device according to claim 1, wherein a thickness of said piezoelectric layer is X and a distance between said plurality of strip electrodes is Y, wherein 0.3 ≦ 0.3. A piezoelectric film element satisfying X / Y ≦ 6.