JP2004179265A - Actuator and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator where flatness is small and inplane dispersion of a d-constant is small and to provide a manufacturing method of the actuator. <P>SOLUTION: The actuator 1 is provided with a piezoelectric substrate 2 formed of a piezoelectric porcelain, surface electrodes 6 arranged in a part of the main face of the piezoelectric substrate 2 and an inner electrode 5 disposed inside the piezoelectric substrate 2. Flatness of the main face of the piezoelectric substrate 2 is not more than 20μm and whole thickness T is not more than 100μm. <P>COPYRIGHT: (C)2004,JPO

Description

【００６７】
本発明の試料Ｎｏ．１〜３、５〜８、１１〜１９及び２１〜３２は、ｄ_３１のバラツキが１５％以下、変位量が７０ｎｍ以上であった。
【００６８】
一方、支持体の平坦度が３０μｍと大きく本発明の範囲外の試料Ｎｏ．４は、ｄ_３１のバラツキが２７％と大きかった。
【００６９】
また、全体の厚みが１０００μｍ（１ｍｍ）と大きく本発明の範囲外の試料Ｎｏ．２０は、変位が２０ｎｍと小さく圧電特性が非常に低いものであった。
【００７０】
さらに、支持体の気孔率が３％と大きく本発明の範囲外の試料Ｎｏ．９は、ｄ_３１のバラツキが３０％と大きかった。
【００７１】
また、スペーサを用いて支持体間の空間に成形体を載置した本発明の範囲外の試料Ｎｏ．１０は、平坦度が４８μｍと大きかった。
【００７２】
【発明の効果】
本発明は、表面部の気孔率を１％以下に制御した支持体が成形体に接触するように、具体的には一対の支持体で成形体を挟持するように配置して焼成することにより、厚み１００μｍ以下の薄層の試料でも平坦度が２０μｍ以下に制御可能となり、支持体に接合した際に発生する残留応力を低減し、圧電体の変形を防止するとともに、同一基板内に設けられた複数の圧電素子の変位バラツキを容易に制御でき、インクジェットプリンタの印刷ヘッドとして好適に用いることができる。
【図面の簡単な説明】
【図１】本発明のアクチュエータを示すもので、（ａ）は概略断面図、（ｂ）は概略平面図、（ｃ）は支持基板を接合した時の概略断面図である。
【図２】本発明のアクチュエータの製造方法を説明するための概略断面図である。
【図３】本発明のアクチュエータの他の製造方法を説明するための概略断面図である。
【符号の説明】
１・・・アクチュエータ
２・・・圧電基板
４・・・圧電振動層
５・・・内部電極
６・・・表面電極
７・・・変位素子
Ｔ・・・アクチュエータの厚み
１０１、１１１・・・セッター
１０２、１１２・・・スペーサ
１０３、１０３ａ、１０３ｂ、１１３・・・支持体
１０４、１０４ａ、１０４ｂ、１１４・・・主面
１０５、１１５・・・成形体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an actuator and a method of manufacturing the same. For example, the present invention relates to an actuator for a fuel injection injector, an actuator for an inkjet printer head, a piezoelectric resonator, an oscillator, an ultrasonic motor, an acceleration sensor, a knocking sensor, or a piezoelectric sensor such as an AE sensor. The present invention relates to an actuator suitably used as an actuator for an ink jet printer head utilizing spread vibration, elongation vibration, and vertical vibration, and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, products using piezoelectric ceramics include, for example, an actuator, a filter, a piezoelectric resonator (including an oscillator), an ultrasonic oscillator, an ultrasonic motor, and a piezoelectric sensor.
[0003]
Among them, the actuator has a very high response speed to an electric signal of the order of 10 ⁻⁶ seconds, and is applied to an actuator for positioning an XY stage of a semiconductor manufacturing apparatus, an ink ejection actuator of an ink jet printer, and the like. I have.
[0004]
Conventionally, piezoelectric ceramics used in such applications have been manufactured by arranging and firing ceramic green sheets having a thickness of several hundred μm directly between a pair of setters made of a porous sintered body. .
[0005]
In addition, a spacer is arranged on a setter base made of a porous body, and a green sheet is arranged in a space formed by placing a setter lid made of a porous body on the spacer, and the green sheet and the setter are placed. It has been proposed to adjust the flatness of the sintered body to 30 to 100 μm by firing in a state where a space is provided so that the gap between the lids is 30 to 100 μm (for example, Patent Document 1).
[0006]
When the ceramic body obtained in this way is applied to a piezoelectric body, the smoothness of the porcelain can be kept below a certain value, so that the breakage when fixing the actuator on a flat surface such as a metal plate to fix it in the printer can be avoided. It has a feature that it can be avoided, and is suitably used as a printer head for an inkjet printer, an XY stage positioning actuator, or the like.
[0007]
[Patent Document 1]
JP-A-2000-281453 (FIG. 3)
[0008]
[Problems to be solved by the invention]
However, in the method of arranging and firing the green sheet so as to sandwich the green sheet with the porous body, a component that easily evaporates through the pores is volatilized. In particular, when an actuator having a thickness of 100 μm or less is obtained, the in-plane variation of the composition is reduced. As it becomes larger, it is difficult to control the surface state of the porous body, so the flatness of the obtained piezoelectric magnetism increases, and the flatness and surface roughness of the sintered body further increase due to the attachment of particles that have been removed from the setter. became.
[0009]
Further, in the method of firing a thin green sheet described in Patent Document 1, the gap between the setter and the green sheet is at least 30 μm, and when obtaining an actuator having a thickness of 100 μm or less, the flatness of the porcelain is large with respect to the thickness. became.
[0010]
When the flatness is large as described above, when the actuator is fixed to the support substrate, the piezoelectric ceramic is stretched so as to correct the curved surface state of the piezoelectric ceramic to a flat state, so that uneven residual stress is generated in the piezoelectric substrate. Occurs. In particular, in the case of an actuator having a plurality of displacement elements provided on a piezoelectric substrate and having a thickness of 100 μm or less, there is a problem that the d constant greatly varies depending on the displacement elements.
[0011]
Therefore, an object of the present invention is to provide an actuator having a small flatness and a small in-plane variation of d constant even when bonded to a supporting substrate, and a method of manufacturing the same.
[0012]
[Means for Solving the Problems]
The present invention can suppress deformation of the green sheet by baking while bringing the green sheet into contact with a support having a dense and flat surface, particularly, while sandwiching the green sheet with the support, and This method is based on the finding that evaporation from the substrate can be suppressed, and this method can realize an actuator having a small flatness and a small in-plane variation in d constant even when bonded to a supporting substrate.
[0013]
That is, the piezoelectric body of the present invention includes a piezoelectric substrate made of a piezoelectric ceramic, a surface electrode provided on a part of the main surface of the piezoelectric substrate, and an internal electrode provided inside the piezoelectric substrate. Wherein the overall thickness is 100 μm or less, and the flatness of the main surface of the piezoelectric substrate is 20 μm or less.
[0014]
In particular, the surface roughness Ra of the main surface of the piezoelectric substrate is preferably 3 μm or less. As a result, when the piezoelectric ceramic is fixed to a metal plate or the like as an actuator, the amount of deformation of the actuator due to correction can be further reduced, so that the residual stress generated inside the actuator can be further suppressed, and as a result, the Even in this case, the in-plane variation of the d constant of the actuator can be effectively reduced.
[0015]
It is preferable that the piezoelectric ceramic is a perovskite compound containing at least Pb. As a result, an actuator having a large displacement and capable of being driven at a low voltage can be manufactured. As a result, further contribution can be expected to higher speed, higher accuracy, and lower cost of the printer.
[0016]
It is preferable that the amount of carbon contained in the piezoelectric ceramic is 0.1% by mass or less. As a result, the insulating properties of the piezoelectric ceramic can be ensured, and displacement failure during polarization processing can be prevented.
[0017]
Further, in the method for manufacturing an actuator according to the present invention, the molded body made of the piezoelectric powder is brought into contact with the main surface of a support having a main surface with a porosity of 1% or less and a flatness of 20 μm or less on the surface. It is characterized by firing, whereby the above-described actuator can be manufactured.
[0018]
Further, the surface roughness Ra of the main surface of the support is preferably 3 μm or less. This can further improve the flatness of the piezoelectric ceramic after firing, reduce residual stress, and suppress composition variation.
[0019]
Furthermore, it is preferable that the molded body is disposed so as to be sandwiched between the pair of supports, and then fired. This makes it possible to easily obtain a flatness of 20 μm or less even with a thin piezoelectric ceramic having a thickness of 100 μm or less.
[0020]
In addition, it is preferable that a plurality of the compacts are provided, and the plurality of the compacts and the support are alternately stacked and baked. As a result, not only is the flatness of the piezoelectric ceramic improved, but also the lead atmosphere in the furnace can be formed stably, so that the distribution of the piezoelectric characteristics of the substrate is stabilized and the variation of the d constant in the substrate is further reduced. Can be.
[0021]
Further, the support may be at least one of alumina, beryllia, zirconia, magnesia, mullite, spinel, bismuth layered compound, tungsten bronze structure compound, Pb-based perovskite structure compound, niobium-based perovskite structure compound, and tantalum-based perovskite structure compound Is preferable. Thereby, the reactivity with the green sheet can be suppressed.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described with reference to the drawings.
[0023]
As shown in FIG. 1A, the actuator 1 of the present invention includes a piezoelectric substrate 2 made of a piezoelectric ceramic, an internal electrode 5 provided inside the piezoelectric substrate 2, and a part of a main surface of the piezoelectric substrate 2. And a displacement element 7 is constituted by the piezoelectric vibration layer 4, the internal electrode 5, and the surface electrode 6 formed on the surface of the piezoelectric substrate 2.
[0024]
In the actuator, for example, as shown in FIG. 1B, the surface electrodes 6 are two-dimensionally arranged at equal intervals, each is independently connected to an external electronic control circuit, and a voltage is applied between the electrodes. Is applied, the piezoelectric vibration layer 4 at the portion sandwiched between the internal electrode 5 and the surface electrode 6 to which the voltage is applied can be displaced. As described above, by applying each displacement element 7 to a print head that is independently controlled, it is possible to contribute to an increase in speed and accuracy of an inkjet printer.
[0025]
According to the present invention, the thickness T of the actuator 1 indicates the thickness of the piezoelectric substrate 2 including the surface electrode 6, and it is important that T is 100 μm or less. With such a thin layer, a large displacement can be obtained, and high-efficiency driving at a low voltage can be realized. Accordingly, in the present invention, in particular, with respect to the demand for higher speed and higher precision accompanying the recent performance improvement of a color printer, the demand can be met by setting the thickness to 100 μm or less. Can contribute to the improvement of the performance of the print head. In particular, in order to further enhance the characteristics as the actuator 1, the thickness is preferably 80 μm or less, more preferably 65 μm or less, and more preferably 50 μm or less.
[0026]
In addition, the lower limit of the thickness T of the actuator 1 is 3 μm, particularly 5 μm, further preferably 10 μm, and more preferably 20 μm in order to have sufficient mechanical strength and prevent breakage during handling and operation. preferable.
[0027]
It is also important that the flatness of the surface of the piezoelectric substrate 2, that is, the flatness of the main surface of the piezoelectric vibrating layer 4 is 20 μm or less. By setting the flatness to 20 μm or less, particularly 15 μm or less, and further to 10 μm or less, for example, as shown in FIG. 1C, the surface of the support substrate 3 in which the groove 3a is formed by the partition 3b is flat. Even when the actuator 1 according to the present invention is joined, the deformation of the actuator 1 due to the joining is small and the residual stress can be reduced, so that the characteristic variation of each displacement element can be reduced.
[0028]
The surface roughness Ra of the piezoelectric substrate 2 is preferably 3 μm or less, particularly 2.5 μm or less, and more preferably 2 μm or less. When the surface roughness Ra is small, it is easy to prevent minute deformation of the actuator when the piezoelectric body is fixed to a metal substrate or the like as an actuator, and the effect of reducing residual stress can be enhanced. Further, there is an effect that the evaporation component is suppressed from volatilizing through the surface unevenness, and the composition variation is further reduced.
[0029]
The piezoelectric substrate 2 including the piezoelectric vibrating layer 4 can be made of a ceramic exhibiting piezoelectricity. Specifically, a Bi layered compound, a tungsten bronze structure material, a perovskite structure compound of an alkali Nb acid compound, lead magnesium niobate ( Examples thereof include substances containing PMN), lead nickel niobate (PNN), lead zirconate titanate containing Pb (PZT), lead titanate, and the like.
[0030]
Among them, a perovskite compound containing at least Pb is particularly preferable. For example, a substance containing lead magnesium niobate (PMN-based), lead nickel niobate (PNN-based), lead zirconate titanate containing Pb (PZT), lead titanate, or the like is preferable. With such a composition, the piezoelectric vibration layer 4 having a high piezoelectric constant can be obtained.
[0031]
In particular, as an example of the perovskite-type crystal, PbZrTiO ₃ which is a crystal containing Pb as an A-site constituent element and containing Zr and Ti as a B-site constituent element can be preferably used. Further, other oxides may be mixed, and as an auxiliary component, other elements may be substituted for the A site and / or the B site as long as the characteristics do not adversely affect the characteristics. For example, a solid solution of Pb (Zn _1/3 Sb _2/3 ) O ₃ and Pb (Ni _1/2 Te _1/2 ) O ₃ to which Zn, Sb, Ni and Te are added as subcomponents may be used. .
[0032]
According to the present invention, it is desirable that the perovskite-type crystal further contains an alkaline earth element as an A-site constituent element. Examples of the alkaline earth element include Ba, Sr, and Ca, and Ba and Sr are particularly preferable in that a high displacement can be obtained. As a result, the relative dielectric constant is improved, so that a higher piezoelectric constant can be exhibited.
[0033]
_{Specifically, Pb 1-x - y Sr} x Ba y (Zn 1/3 Sb 2/3) a (Ni 1/2 Te 1/2) b Zr 1-a-b-c Ti c O 3 + α Mass% Pb _1/2 NbO ₃ (0 ≧ x ≧ 0.14, 0 ≧ y ≧ 0.14, 0.05 ≧ a ≧ 0.1, 0.002 ≧ b ≧ 0.01, 0.44 ≧ c ≧ 0.50, α = 0.1 to 1.0).
[0034]
Preferably, the piezoelectric substrate 2, especially the piezoelectric vibration layer 4, contains 0.1% by mass or less of carbon, particularly 0.07% by mass or less. Since carbon contributes to the insulating property of the piezoelectric material and causes insulation failure during polarization, by suppressing the amount in the above range, it is possible to suppress the current from flowing during polarization and to polarize to a saturated polarization state. Displacement failure due to failure can be prevented.
[0035]
The porosity of the piezoelectric substrate 2 is preferably 1% or less, particularly 0.5% or less, and more preferably 0.3% or less. By reducing the porosity, the strength of the actuator 1 is increased, and when used as an inkjet print head, it is possible to effectively suppress ink leakage due to ink seepage into porcelain.
[0036]
Any material may be used as the material of the internal electrode 5 and the surface electrode 6 as long as it has conductivity, and Au, Ag, Pd, Pt, Cu, Al, an alloy thereof, or the like is used. Also, the thickness of the electrodes 5 and 6 needs to be such that it has conductivity and does not hinder the displacement, and is preferably 0.5 to 5 μm, particularly preferably about 1 to 3 μm.
[0037]
When using the actuator of the present invention as a printing head of an ink jet printer can be used as a piezoelectric constant, for example a d ₃₁ mode. Exhibits sufficient discharge performance as a printing head of an ink jet printer, in order to realize a fine high-speed _{printing, d 31} is 200 pm / V or more, particularly 225pm / V or more, and further preferably not 250 pm / V or more .
[0038]
Next, the manufacturing method of the actuator of the present invention will be described by taking as an example a case where PZT is used as the piezoelectric ceramic.
[0039]
First, a PZT powder having a purity of 99% and an average particle diameter of 1 μm or less is prepared as a piezoelectric powder used as a raw material.
[0040]
An appropriate organic binder is added to the PZT powder to form a tape, a desired portion of the tape is coated with an Ag-Pd paste as an internal electrode, and a via hole is formed at a desired portion and the inside of the via hole is formed. An electrode was formed. Next, the obtained green sheets are laminated. Also, if desired, it is cut into a specific shape.
[0041]
In order to fire the compact obtained by lamination, the compact is mounted on a jig and placed in a firing furnace. An example of the arrangement is shown in FIG. That is, the support 103a is placed on the setter 101 via the spacer 102, and the molded body 105 is placed on the support 103a, and the porosity of the surface portion is 1% or less and the flatness is 20 μm or less. It is important that the support 103 having a surface and the molded body 105 are brought into contact with each other.
[0042]
In the present invention, as long as the molded body 105 is placed on the support 103a, there may be anything on the molded body 105, for example, a porous body may be placed. Placing the support 103b having a similar main surface and placing the molded body 105 so as to be sandwiched between the pair of supports 103a and 103b can effectively suppress the variation in composition and can provide a flatness of 20 μm or less. Is preferred because it can be easily obtained.
[0043]
According to the present invention, it is important that the flatness of the main surfaces 104a and 104b where the supports 103a and 103b are in contact with the molded body 105 is 20 μm or less. Since the support 103 is in contact with the molded body 105, the flatness of the main surface 104 in contact with the molded body 105 can reduce the flatness of the surface of the sintered body obtained by firing the molded body 105, and the surface becomes flat. A compact piezoelectric ceramic can be obtained. In particular, in order to obtain a sintered body having a smaller flatness, the flatness of the main surface of the support 103 is preferably 15 μm or less, more preferably 10 μm or less.
[0044]
Further, according to the present invention, the surface portions of the main surfaces 104a and 104b where the supports 103a and 103b come into contact with the molded body 105 have a porosity of 1% or less, further 0.5% or less, and further 0.3% or less. % Is important. When the main surface 104 of the support body 103 having such a small porosity is dense, degranulation is small, particles attached to the surface of the compact are reduced, and the flatness and surface roughness of the piezoelectric ceramic obtained by sintering are reduced. Can be improved.
[0045]
The surface portion means the surface of the main surface 104 that forms the contact surface with the molded body. However, since the porosity needs to be polished, the minimum thickness actually required for polishing is required. For example, a thickness of several μm is required, and this is substantially called a surface portion.
[0046]
Further, in a conventional support made of a porous body, components volatilized from the molded body during firing are scattered outside through continuous pores of the support, while at least the surface portion of the main surface 104 is formed. Since the dense support 103 is used, scattering of volatile components can be significantly suppressed. As described above, the in-plane variation of the piezoelectric characteristics can be further improved by suppressing the evaporation of the volatile component from the molded body.
[0047]
The supports 103a and 103b are preferably dense as a whole. Such a dense body can be regenerated at low cost by processing the surface. Alternatively, a sintered body having a dense surface and a relatively high porosity inside can be used. For example, when sintering proceeds more easily on the surface than on the inside during sintering, the porosity of the surface layer of at least 0.1 mm, particularly 0.3 mm, and more preferably 0.5 mm from the surface is 1% or less, particularly 0.1 mm. It is preferably 5% or less, more preferably 0.3% or less.
[0048]
If desired, only the surface can be made dense. For example, the surface of the ceramic sintered body having a porosity of about 2 to 8% is polished and coated with a ceramic layer so that the main surfaces 104a and 104b of the supports 103a and 103b have pores of 0.1% or less. Rate. In particular, it is formed to a thickness of several tens μm or more, more preferably 50 μm or more, and more preferably 100 μm or more by CVD (chemical vapor deposition), and is mirror-polished to have a porosity of 1% or less and a flatness of 20 μm. It can be: This is when the cost for manufacturing the entire large support with a dense sintered body is high, or when it is difficult to synthesize a dense sintered body, or when the molded body and the support are likely to react. It is especially effective for
[0049]
The surface roughness Ra of the support 103 is preferably 3 μm or less, particularly 2.5 μm or less, and more preferably 2 μm or less. By setting the surface roughness Ra of the support 103 as described above, the flatness of the piezoelectric ceramic can be further improved. In addition, the gap between the molded body and the support serves as a diffusion path to evaporate volatile components from the molded body, thereby suppressing in-plane variation in composition.
[0050]
The support used in the present invention is at least one of alumina, beryllia, zirconia, magnesia, mullite, spinel, bismuth layered compound, tungsten bronze structure compound, Pb-based perovskite structure compound, niobium-based perovskite structure compound, and tantalum-based perovskite structure compound. Preferably, it contains a species.
Each of them is a substance of the same quality as the piezoelectric substance or a substance having poor reactivity. By using such a substance for the support, the characteristics of the piezoelectric body can be stabilized.
[0051]
In the case of firing a plurality of laminated molded bodies, for example, as shown in FIG. 3, a configuration in which a support body 113 and a molded body 115 are alternately stacked on a setter 111 via a spacer 112 can be adopted. . By setting the flatness of the main surface 114 of the support 113 to 20 μm or less and the porosity of the surface of the main surface 114 to 1% or less, the same effect as in the case of using the configuration of FIG. 2 can be expected. Further, by arranging a plurality of compacts in this way, the lead atmosphere in the furnace is stabilized, and there is also an effect of further reducing the variation of the d constant due to the composition variation.
[0052]
Prior to firing the laminated molded body, a degreasing treatment may be performed at a temperature of about 400 ° C. to 900 ° C., if desired.
[0053]
A surface electrode 6 is formed on the surface of the obtained sintered body, and the actuator can be manufactured by polarization.
[0054]
Thus, by employing the manufacturing method of the present invention, even when manufacturing an actuator having a thin layer having a thickness of 100 μm or less, the deformation of the porcelain caused by the variation in shrinkage during firing can be reduced. Residual stress generated when fixing to the support can be reduced, the d constants of a large number of displacement elements constituting the actuator become uniform, and variations in displacement amount can be significantly reduced. In addition, by applying such an actuator to a print head of an inkjet printer, high-speed and high-accuracy characteristics can be improved.
[0055]
【Example】
An actuator of the present invention was produced, and this was adhered to the support shown in FIG.
[0056]
First, a piezoelectric ceramic powder containing lead zirconate titanate having a purity of 99% or more was prepared as a raw material.
[0057]
The green sheet is obtained by adding butyl methacrylate as a water-based binder, ammonium polycarbonate to a dispersant, and isopropyl alcohol and pure water to a solvent to a powder of a ceramic material for a piezoelectric material containing lead zirconate titanate as a main component. After mixing, this slurry was formed on a carrier film by a doctor blade method in a sheet shape having a thickness of about 30 μm.
[0058]
Also, green sheets were prepared in the same manner using various types of piezoelectric ceramic powders. Further, an internal electrode paste was prepared. The obtained internal electrode paste was printed at a thickness of 4 μm on the surface of the green sheet to form internal electrodes. Further, one green sheet on which the internal electrode paste was not printed was laminated between two green sheets with the surface on which the internal electrodes were printed facing upward, and pressed and pressed to obtain a laminated molded product.
[0059]
After degreasing the laminated molded body, as shown in FIG. 2, the laminated molded body was placed in a firing furnace so as to be sandwiched by a support (d1). The sample No. 10 is to place a spacer having a thickness of 600 μm on the porous support, place another porous support on the spacer, place the laminated molded product between the upper and lower supports, and place it in a firing furnace. (D2).
[0060]
This was kept at the temperature shown in Table 1 and in an atmosphere of 99% or more of oxygen for 2 hours and fired to produce a laminate including a piezoelectric vibrating layer and internal electrodes. Surface electrodes were formed on one side of the surfaces. Au electrodes were applied by screen printing to form 600 surface electrodes per substrate. This was baked in the air at 600 to 800 ° C.
[0061]
The porosity of the obtained piezoelectric substrate was calculated by cutting the sintered body, processing the cross section of the sintered body into a mirror surface state, observing it with a microscope, and calculating the area of the pores within a predetermined area. For the flatness of the surface of the support and the surface of the piezoelectric substrate, a change in height was measured by scanning from one end to the other end of the piezoelectric substrate using a laser displacement meter. At that time, the thickness was calculated by correcting the thickness of the surface electrode.
[0062]
_{D 31} of the actuator was measured 10 points by the resonance method using an impedance analyzer (Agilent Technologies Ltd. 4194A), and the average value was calculated. Then, to calculate the difference between the average value of d _31, it was expressed as a percentage of the maximum value as the d ₃₁ variations.
[0063]
In the measurement of the displacement amount, in consideration of use as a print head for an ink jet printer, as shown in FIG. 1C, the actuator 1 produced above was bonded to a support 3 having a groove 3a and a partition 3b, The displacement element 7 was manufactured such that the piezoelectric vibration layer 4 was sandwiched between the internal electrode 5 and the surface electrode 6. Then, the actuator is irradiated with a laser beam from the support 3 side through the groove 3a by the laser Doppler displacement meter, and the center and the peripheral portion of the actuator which are in contact with the groove 3a of the support 3 are measured to measure the displacement. Then, the average value was calculated. The results are shown in Table 1.
[0064]
The thickness of the actuator was measured with a micrometer, and the surface roughness of the support and the actuator was measured with a stylus type surface roughness meter.
[0065]
The support shown in Table 1 was used.
[0066]
[Table 1]

[0067]
Sample No. of the present invention In Examples 1 to 3, 5 to 8, 11 to 19, and 21 to ₃₂ , the variation of d31 was 15% or less, and the displacement was 70 nm or more.
[0068]
On the other hand, the flatness of the support was as large as 30 μm, and the sample No. was out of the range of the present invention. _4, the variation of the _{d 31} was as large as 27%.
[0069]
Further, the sample No. having a large overall thickness of 1000 μm (1 mm) and out of the scope of the present invention. In No. 20, the displacement was as small as 20 nm and the piezoelectric characteristics were very low.
[0070]
Further, the porosity of the support was as large as 3%, and the sample No. was out of the range of the present invention. _9, the variation of the _{d 31} was as large as 30%.
[0071]
In addition, a sample No. out of the scope of the present invention in which the compact was placed in the space between the supports using the spacer. In No. 10, the flatness was as large as 48 μm.
[0072]
【The invention's effect】
The present invention is characterized in that a support whose surface porosity is controlled to 1% or less is brought into contact with the molded body, specifically by arranging and firing such that the molded body is sandwiched between a pair of supports. The flatness of a sample having a thickness of 100 μm or less can be controlled to 20 μm or less, reducing the residual stress generated when the sample is joined to a support, preventing deformation of the piezoelectric body, and being provided on the same substrate. The variation in displacement of the plurality of piezoelectric elements can be easily controlled, and the piezoelectric element can be suitably used as a print head of an inkjet printer.
[Brief description of the drawings]
FIG. 1 shows an actuator of the present invention, in which (a) is a schematic sectional view, (b) is a schematic plan view, and (c) is a schematic sectional view when a supporting substrate is joined.
FIG. 2 is a schematic cross-sectional view for explaining a method for manufacturing an actuator of the present invention.
FIG. 3 is a schematic cross-sectional view for explaining another method for manufacturing the actuator of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Actuator 2 ... Piezoelectric substrate 4 ... Piezoelectric vibration layer 5 ... Internal electrode 6 ... Surface electrode 7 ... Displacement element T ... Actuator thickness 101, 111 ... Setter 102, 112 ... spacers 103, 103a, 103b, 113 ... supports 104, 104a, 104b, 114 ... main surfaces 105, 115 ... molded bodies

Claims (9)

An actuator comprising: a piezoelectric substrate made of a piezoelectric ceramic; a surface electrode provided on a part of a main surface of the piezoelectric substrate; and an internal electrode provided inside the piezoelectric substrate. Is 100 μm or less, and the flatness of the main surface of the piezoelectric substrate is 20 μm or less. 2. The actuator according to claim 1, wherein a surface roughness Ra of a main surface of the piezoelectric substrate is 3 μm or less. 3. The actuator according to claim 1, wherein the piezoelectric ceramic is a perovskite compound containing at least Pb. 4. The actuator according to claim 1, wherein carbon contained in the piezoelectric ceramic is 0.1% by mass or less. A method for manufacturing an actuator, comprising: sintering a molded body made of piezoelectric powder while contacting the main surface of a support having a main surface with a porosity of 1% or less and a flatness of 20 μm or less on the surface. . 6. The method according to claim 5, wherein a surface roughness Ra of the main surface of the support is 3 μm or less. The method for manufacturing an actuator according to claim 5, wherein the molded body is disposed so as to be sandwiched by a pair of the support members, and is fired. 8. The method of manufacturing an actuator according to claim 5, wherein a plurality of the compacts are provided, and the plurality of compacts and the support are alternately stacked and arranged and fired. The support contains at least one of alumina, beryllia, zirconia, magnesia, mullite, spinel, bismuth layered compound, tungsten bronze structure compound, Pb-based perovskite structure compound, niobium-based perovskite structure compound, and tantalum-based perovskite structure compound. The method for manufacturing an actuator according to any one of claims 5 to 8, wherein:

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