JP2005159042A - Piezoelectric actuator and liquid injector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric actuator and a liquid injector in which even if a displacement is repeatedly made, it is hard for cracks to occur. <P>SOLUTION: The piezoelectric actuator is constituted of a plurality of displacement areas and a non-displacement area provided surrounding the displacement area on the same flat plane. A grain boundary between two faces of a main crystal of a piezoelectric layer does not substantially contain a glass phase, and a common electrode, the piezoelectric layer and a surface electrode are laminated in this order on a vibration plate substrate, and a plurality of the surface electrodes are arranged two-dimensionally on a surface of the piezoelectric layer. The displacement area is formed of the piezoelectric layer, the surface electrode, a region opposed to the surface electrode of the command electrode, and a region opposed to the surface electrode of the vibration plate, preferably. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to various printers and recorders for ejecting minute droplets onto the surface of a recording medium made of cloth, paper, plastic, metal, glass and ceramics, a semiconductor substrate such as silicon or GaAs, etc. The present invention relates to a piezoelectric actuator and a liquid ejecting apparatus that can be suitably used for a printing head that is preferably used for a printing apparatus such as a facsimile machine or a printing machine used for pattern formation in the textile printing field and the ceramic industry.

  In recent years, with the penetration of multimedia, non-impact recording devices using inkjet and thermal transfer methods have been developed in place of impact recording devices, and the range of use is expanding in various industrial and general household fields. is there.

  Among such non-impact recording apparatuses, a recording apparatus using an ink-jet system is attracting attention because it is easy to increase the number of gradations and colors and has a low running cost.

  A print head used in a recording apparatus using the ink jet system pressurizes liquid in a liquid flow path provided in a flow path member, and ejects liquid droplets from a liquid pressurizing chamber via a nozzle to perform recording. It is recorded on a medium. Such a flow path member includes an actuator for pressurizing a liquid and a flow path member that forms a flow path for the liquid.

  For example, as shown in FIG. 3A, the piezoelectric actuator 21 has a structure provided on the flow path member 23 (see, for example, Patent Document 1). In the flow path member 23, a plurality of ink pressurization chambers 23 a are partitioned by partition walls 23 b, and the ink pressurization chambers 23 a are arranged in parallel so as to contact the piezoelectric actuator 21.

  In the piezoelectric actuator 21, a common electrode 25, a piezoelectric ceramic layer 24, and a surface electrode 26 are formed in this order on the surface of the diaphragm 22. As shown in FIG. 3B, a plurality of surface displacement electrodes 26 are arranged on the surface of the piezoelectric ceramic layer 24 to form a plurality of piezoelectric displacement elements 27. The piezoelectric actuator 21 may be formed with hundreds of surface electrodes, and is disposed on the flow path member 23 so that the surface electrodes 26 are respectively positioned immediately above the ink pressurizing chamber 23a.

  Then, a voltage is applied between the common electrode 25 and the predetermined surface electrode 26 to displace the piezoelectric ceramic layer 24 immediately below the surface electrode 26, thereby pressurizing the ink in the ink pressurizing chamber 23a to flow. Ink droplets can be ejected from the liquid ejection port 28 opened on the bottom surface of the path member 23.

A glass component is contained as an accessory component.
JP 11-34321 A

  However, in the case of using the piezoelectric actuator in which the displacement area and the non-displacement area are arranged on the same plane as in the above-described print head, stress is applied to the displacement portion and its periphery due to repeated displacement. When ceramics are used, there is a problem that cracks are generated and ink leakage or displacement abnormality of the piezoelectric displacement element occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a piezoelectric actuator and a liquid ejection device that are unlikely to generate cracks even when displacement is repeated.

  The piezoelectric actuator according to the present invention is a piezoelectric actuator comprising a plurality of displacement regions and a non-displacement region provided so as to surround the displacement regions on the same plane, wherein the triple-dot grains of the main crystal of the piezoelectric layer A glass phase is present in the boundary, and there is substantially no glass phase in a grain boundary between the two faces of the main crystal.

  In particular, a common electrode, a piezoelectric layer, and a surface electrode are laminated in this order on the diaphragm substrate, and the surface electrode is two-dimensionally arranged on the surface of the piezoelectric layer, and a displacement region is the piezoelectric layer. It is preferable to be formed by a body layer, the surface electrode, a portion of the common electrode facing the surface electrode, and a portion of the diaphragm facing the surface electrode.

  The piezoelectric body is preferably made of a perovskite type compound containing lead.

  The piezoelectric body preferably contains Ti and / or Zr.

  It is preferable that the glass phase of the triple point grain boundary contains Si.

  The liquid ejection apparatus of the present invention has a liquid ejection nozzle on one surface, a mounting portion for a piezoelectric actuator on the other surface, and a surface of a flow path member having a liquid flow path inside. 4. The piezoelectric actuator according to any one of 4 is provided.

  The cracks that occur during the driving of the piezoelectric ceramics were obtained from the new knowledge that cracks are likely to occur when the grain boundaries between the two faces of the main crystal contain glass as the grain boundary phase. By reducing the amount of glass present in the grain boundary phase, it is possible to improve the resistance to repeated displacement, and as a result, the occurrence of cracks can be suppressed even when the displacement is repeatedly performed, leading to the present invention. Is.

  The mechanism of crack generation is not clear, but since the stress applied at the displacement part is large, it is thought that if there is glass at the grain boundary between two faces, fatigue occurs due to repeated stress, and gaps are gradually generated between the main crystal grains.

  In particular, a common electrode, a piezoelectric layer, and a surface electrode are laminated in this order on the diaphragm substrate, and the surface electrode is two-dimensionally arranged on the surface of the piezoelectric layer, and a displacement region is the piezoelectric layer. Since it is formed by a body layer, the surface electrode, a portion of the common electrode facing the surface electrode, and a portion of the diaphragm facing the surface electrode, this is suitable for a droplet discharge device. As a result, a small amount of droplets can be ejected into a minute space.

  Since the piezoelectric body is made of a perovskite type compound containing lead, a large displacement can be obtained, and a piezoelectric actuator having excellent displacement characteristics can be easily obtained.

  Since the piezoelectric body contains Ti and / or Zr, it is easy to obtain a piezoelectric actuator having stable piezoelectric characteristics.

  Since the glass phase of the triple point grain boundary contains Si, a denser piezoelectric body can be obtained, and as a result, more excellent piezoelectric characteristics can be realized.

  Since the liquid ejecting apparatus of the present invention includes the above-described piezoelectric actuator, it is possible to obtain a liquid ejecting apparatus with high long-term reliability. If this is used in an ink jet head, high-definition and high-quality printing can be stabilized. Can be obtained.

  The present invention will be described with reference to the drawings. 1A and 1B show the structure of a piezoelectric actuator according to an embodiment of the present invention. FIG. 1A is a sectional view of the piezoelectric actuator, and FIG. 1B is a sectional view showing a state in which the piezoelectric actuator is joined to a restraining member. , (C) is a plan view of (b).

  As shown in FIG. 1A, in the piezoelectric actuator 1 of the present invention, a common electrode 5, a piezoelectric layer 4, and a surface electrode 6 are laminated in this order on a diaphragm 2. The surface electrode 6 has a plurality of surface electrodes 6 arranged two-dimensionally on the surface of the piezoelectric layer 4 (see FIG. 1 (c)). It is preferable to arrange them at regular intervals.

  Further, as shown in FIGS. 1B and 1C, the actuator 1 of the present invention has a surface electrode 6 and a piezoelectric layer when it is joined to a restraining member 3 composed of a groove 3a and a partition wall 3b. 4 facing the surface electrode 6 (hereinafter simply referred to as the piezoelectric layer 4), the portion facing the surface electrode 6 of the common electrode 5 (hereinafter simply referred to as the common electrode 5), and the surface of the diaphragm 2. A displacement region 7a is formed by a portion facing the electrode 6 (hereinafter simply referred to as the diaphragm 2).

  A non-displacement region 7b is provided around the displacement region 7a so as to surround the displacement region 7a. That is, a piezoelectric actuator is constituted by a plurality of displacement regions 7a and a non-displacement region 7b provided so as to surround the displacement region 7a on the same plane. The size of the surface electrode can be made substantially the same as the size of the opening on the piezoelectric actuator side of the groove 3a.

  By adopting such a configuration, when a voltage is applied between the surface electrode 6 and the common electrode 5 constituting the specific displacement element 7a, the corresponding displacement region 7a is deformed so as to protrude toward the groove 3a side of the restraining member. On the other hand, the non-displacement region 7b is fixed to the partition wall 3b and is not displaced.

  Since the piezoelectric layer 4 constituting the displacement region 7a to be displaced has a large stress applied to the boundary portion between the displacement region 7a and the non-displacement region 7b, a crack is generated in the conventional piezoelectric actuator during repeated deformation. There was a thing. As a result of investigating the cause, it is caused by the glass phase present at the grain boundary between the main crystal grains constituting the piezoelectric ceramic of the piezoelectric layer 4. It was inferred that this was fatigue failure of the glass phase contained in the boundary.

  Therefore, according to the present invention, it is important that the intergranular grain boundary of the main crystal grain does not substantially contain a glass phase. For example, the composition can be adjusted so that the glass phase does not precipitate at the grain boundaries between the two faces. When a sintering aid is required, it is preferable to deposit the sintering aid as sub-crystal particles. Such secondary crystal particles do not participate in the bond between the main crystal particles, and therefore may exist if the amount of the secondary crystal particles is not extremely large.

  In addition, even if the sub-crystal particles are precipitated, there are cases where they are at the grain boundary between the two faces of the main crystal particles, and in that case, there is a risk of cracking, so it is important to prepare the sub-crystal particles. Needless to say, it is important to remove the glass phase at the grain boundary between the two faces.

  It is also possible to deposit a sintering aid at the triple point of the main crystal particles. This triple point is also a site that does not have a main influence on the bonding between the main crystal grains, and by causing a crystal or glass phase to precipitate at the triple point, the occurrence of cracks can be suppressed even if the displacement is repeated. Therefore, it is important to concentrate the glass phase at the triple point, reduce the glass phase at the grain boundary between the two faces, and prevent the generation of cracks starting from the glass phase.

  In the present invention, “substantially no glass phase” means that the width of a grain boundary between two faces is 12 nm or less, particularly 10 nm or less, more preferably 8 nm, as observed with a transmission electron microscope (TEM). It is the following thickness, and the thing of the grade which cannot detect a glass phase there is pointed out.

  Moreover, the said glass phase is comprised from the oxide containing elements, such as Si and Al, for example. The glass phase may contain fine crystal grains, and the fine crystal grains mainly contain Al.

  In addition, the lead (Pb) component contains Pb as the main crystal component, so that Pb dissolves in the liquid phase from the piezoelectric ceramic particles of the main crystal during the sintering process, and segregates to the triple point during cooling. Since it becomes a field phase, controlling the precipitation rate is also effective for controlling the glass phase.

  If the piezoelectric layer 4 contains a large amount of glass component, it tends to precipitate at the grain boundary between the two faces, so the content is preferably reduced. It is desirable that the content of the glass component is 50 to 1000 ppm, particularly 100 to 7a00 ppm, more preferably 150 to 600 ppm in terms of oxide. Thereby, it becomes easy to easily prevent the glass phase from precipitating at the triple-point grain boundary and precipitating the excess glass phase to the interfacial grain boundary phase while maintaining high sinterability. Examples of the glass component include Al and Si oxides.

  For the piezoelectric layer 4 and the diaphragm 2, ceramics exhibiting piezoelectricity can be used. Specifically, a Bi layer compound, a tungsten bronze structure material, a perovskite structure compound of an Nb acid alkali compound, lead magnesium niobate (PMN) System), lead nickel niobate (PNN system), lead zirconate titanate (PZT) containing Pb, lead titanate and the like.

  Of these, a perovskite type compound containing at least lead (Pb) is particularly preferable. For example, lead magnesium niobate (PMN), nickel niobate (PNN), lead zirconate titanate (PZT) containing Pb, lead titanate and the like are preferable. With such a composition, the piezoelectric layer 4 having a high piezoelectric constant can be obtained.

In particular, as an example of the perovskite crystal, PbZrTiO ₃ which is a crystal containing Pb as an A site constituent element and Ti and Zr as B site constituent elements can be preferably used. In addition, other oxides may be mixed, and as a subcomponent, other elements may be substituted at the A site and / or B site as long as the characteristics are not adversely affected. For example, Zn, Sb, Ni, and Te may be added as accessory components, and a solid solution of Pb (Zn _1/3 Sb _2/3 ) O ₃ and Pb (Ni _1/2 Te _1/2 ) O ₃ may be used. .

  According to the present invention, it is desirable to further contain an alkaline earth element as the A site constituent element in the perovskite crystal. Examples of alkaline earth elements include Ba, Sr, and Ca, and Ba and Sr are particularly preferable because high displacement can be obtained. As a result, the dielectric constant is improved, and as a result, a higher piezoelectric constant can be exhibited.

_{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).

  When the surface of the piezoelectric actuator of the present invention is constituted by the piezoelectric layer 4, the crystal grain size of the piezoelectric layer 4 is preferably 1 to 3 μm, particularly preferably 1.5 to 2.5 μm. By making such a crystal grain size, R at the tip of the dent between crystal grains is reduced, and the occurrence of microcracks and / or the development of microcracks when driven repeatedly as a displacement element is more effectively suppressed. In addition, it becomes easy to obtain excellent piezoelectric characteristics with a large piezoelectric vibration, particularly a higher piezoelectric constant.

  The material of the common electrode 5 and the surface electrode 6 may be any material as long as it has conductivity, and Au, Ag, Pd, Pt, Cu, Al, and alloys thereof are used. Further, the thicknesses of the electrodes 5 and 6 must be conductive and do not hinder the displacement, and are 0.1 to 5 μm, particularly 0.2 to 3 μm, and further about 0.3 to 1 μm. Is preferred.

  The piezoelectric laminate having the above-described structure has features such that a large displacement is obtained at a low voltage, and there is little characteristic deterioration even when it is repeatedly vibrated, resulting in high reliability. A piezoelectric actuator for an inkjet printer, a piezoelectric resonator, And can be suitably applied to electronic components such as oscillators.

In order to form such a piezoelectric layer, the composition of the piezoelectric material, the raw material powder particle size and particle size distribution, the dispersion state of the raw material powder, the molding conditions, the firing conditions, and the like can be mentioned. For example, it is preferable to control the content of an oxide that forms a glass phase such as SiO ₂ , Al ₂ O ₃ , or PbO in the raw material. It is desirable to set the content of these glass phases so as not to generate an excessive glass component that cannot be held at the grain boundary triple point.

It is also an effective method to control the particle size of the raw material powder. The triple point boundaries of the main crystal particles made of the piezoelectric ceramic are smaller in size than the main crystal particles, so that the particle size of the raw material powder that forms the glass phase, for example, SiO ₂ , Al ₂ O ₃ is set to the main crystal material. It can be made smaller than the particle size of the powder.

  In addition, the glass phase forms a liquid phase during firing, but the reaction between the main crystal phase and subcomponents such as the glass phase and the properties of the liquid phase such as viscosity and surface tension vary depending on the firing conditions. Therefore, it is desirable to control the glass phase so as to easily concentrate on the triple point grain boundary.

  FIG. 2 is a schematic view of a TEM image photograph obtained by observing the piezoelectric layer according to the present invention with a TEM. In FIG. 2A, 101 is a main crystal particle made of piezoelectric ceramics, and 102 is a triple-point grain boundary 102 surrounded by three crystal grains 101. In the triple point grain boundary 102, glass exists as a grain boundary phase.

  2B is an enlarged view of a circle in FIG. 1A, and the thickness of the grain boundary phase is indicated by T. FIG. In TEM observation, even if a grain boundary between two faces is observed, there is no grain boundary phase, and a grain boundary with a disordered crystal orientation may be observed with a certain thickness. According to the elemental analysis, it is important that there is no glass phase at the grain boundary between the two faces.

  Further, the thickness T of the grain boundary phase is preferably 12 nm or less, particularly 10 nm or less, and more preferably 8 nm or less so that it is difficult to form the grain boundary phase. By reducing the grain boundary phase, the grain boundary phase diffuses to the triple point, and the grain boundary phase substantially disappears at the grain boundary between the two faces. Thereby, the grain boundary between two surfaces becomes strong and there is an effect of suppressing the occurrence of cracks.

  In the droplet discharge device of the present invention, it is important that the piezoelectric actuator is provided on the surface of the flow path member. The channel member has a liquid discharge nozzle on one surface, a piezoelectric actuator mounting portion on the other surface, and a liquid channel inside.

  For example, the pressurizing chamber member shown in FIG. 3 can be used as the restraining member. That is, the piezoelectric actuator 21 has a structure provided on the pressurizing chamber member 23. In the pressurizing chamber member 23, a plurality of liquid pressurizing chambers 23 a are partitioned by partition walls 23 b, and the liquid pressurizing chambers 23 a are arranged side by side so as to contact the piezoelectric actuator 21.

  In the piezoelectric actuator 21, a piezoelectric ceramic layer 24 is provided on a conductive diaphragm 25 that also serves as a common electrode, and a surface electrode 26 is provided on the piezoelectric ceramic layer 24. As shown in FIG. 3B, a plurality of the surface electrodes 26 are arranged on the surface of the piezoelectric ceramic layer 24, thereby forming a plurality of piezoelectric displacement portions 27. The piezoelectric actuator 21 is disposed on the flow path member 23 so that the surface electrode 26 is positioned immediately above the ink pressurizing chamber 23a.

  The print head as described above applies a voltage between the common electrode 25 and the predetermined surface electrode 26 to displace the piezoelectric ceramic layer 24 immediately below the surface electrode 26, thereby causing ink in the ink pressurizing chamber 23 a to move. The liquid droplets can be ejected from the liquid ejection port 28 opened in the bottom surface of the flow path member 23.

  That is, when the displacement region 27a of the actuator 21 is displaced, a droplet is ejected from the nozzle hole 28 provided corresponding to the actuator 27a. Further, when another actuator 27a is displaced, a droplet is ejected from a nozzle hole 28 provided corresponding to this other actuator. As described above, the droplets ejected from each nozzle hole 28 are independently controlled for each nozzle hole 28, and the droplets can be ejected to a desired portion at a desired time.

  By adopting such a configuration, a desired amount of liquid droplets can be ejected to a specific minute region of the space, and if applied to an ink jet print head, high-precision and high-definition printing becomes possible.

  Since the liquid droplet ejection device of the present invention uses the above-described flow path member, the formation of a large build-up in the flow path is prevented, so that the traveling direction of the liquid droplets and the amount of liquid droplets vary. In particular, a uniform liquid ejection can be achieved, and in particular, a print head, a mechanism for supplying ink to the print head, and a medium such as paper and cloth to which the ink ejected from the nozzle holes of the print head is fixed are set at a specific speed. When applied to an ink jet printer equipped with a mechanism for feeding out, a beautiful and beautiful printing state can be obtained.

  The plurality of surface electrodes 26 are independently connected to an external electronic control circuit. In the piezoelectric displacement element 27 corresponding to each surface electrode 26, the displacement region 27 a is displaced by applying a voltage between the common electrode 25 and the surface electrode 26. As described above, by disposing a plurality of piezoelectric displacement elements 27 on the surface, it is possible to discharge droplets only at specific positions in a finely divided space. Ink having a desired color tone can be applied to small dots.

  In particular, the liquid droplet ejection device of the present invention is an electronic device such as a printer or a printing machine including a print head, an ink tank that supplies ink to the print head, and a recording paper transport mechanism for printing on recording paper. In the case of a printer, it is possible to easily realize high-speed, high-precision, and high-quality printing and provide a highly reliable product.

  First, a piezoelectric powder containing high purity lead zirconate titanate (PZT) having a Si and Al content of 100 ppm or less was prepared as a raw material. This raw material powder was molded to produce a green sheet. Also, an internal electrode paste containing Ag—Pd as a main component was prepared, and an electrode pattern having a thickness of 4 μm was printed on the surface of a part of the plurality of green sheets obtained previously. An electrode was formed.

  A green sheet and a green sheet having an internal electrode formed on the surface were laminated, and the obtained laminated molded body was fired.

Each raw material powder of high-purity Pb ₂ O ₃ , ZrO ₂ , TiO ₂ , BaCO ₃ , ZnO, SrCO ₃ , Sb ₂ O ₃ , NiO, TeO _{2 is used as} the raw material powder, and the sintered body is Pb _{1-xy 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 (x = 0.04, y = 0.02 , A = 0.075, b = 0.005, c = 0.4.2), a predetermined amount is weighed, and the quantitative ratio shown in Table 1 with respect to this composition A minor component was added.

  The above prepared powder was wet-mixed for 20 hours by a ball mill, and then the mixture was dehydrated and dried. Thereafter, the mixture was calcined at 800 ° C. for 3 hours, and the obtained calcined product was wet pulverized again with a ball mill.

  Thereafter, an organic binder, water, a dispersing agent and a plasticizer are mixed into the pulverized product to prepare a slurry, and the thickness after firing is determined by a roll coater method generally used for forming a thin green sheet. A green sheet was prepared in consideration of the shrinkage rate in advance so as to have the size shown in the table.

  Thereafter, the green sheet was punched into a short shape using a mold to prepare a plurality of short sheets. Next, the electrode was apply | coated to the green sheet surface by screen printing on this short-shaped sheet | seat surface using the electrode paste which consists of Ag-Pd for a common electrode and an individual electrode.

  Next, the green sheet coated with the electrode and the green sheet coated with no electrode are stacked so that the structure shown in FIG. 1 is formed, that is, a plurality of displacement elements are formed on the surface of the substrate, and heat is applied. The laminated actuator molded body was manufactured by pressure bonding.

  Finally, this compact was fired at 970 ° C. for 3 hours to obtain an actuator.

  Next, the actuator was applied to an inkjet print head. The grain boundary phase was observed with TEM (200,000 times), the grain boundary phase was measured by elemental analysis, and the crystal phase and the glass phase were judged from the electron diffraction pattern.

Further, pigment water was supplied to the liquid jetting device, the actuator was driven at 25 V, 2 kHz, continuous driving was performed every 50 hours, and the presence or absence of cracks was observed every time driving was stopped. The results are shown in Table 1.

  Sample No. of the present invention. Since 1-5 and 7-9 have substantially no glass phase at the grain boundary between the two faces, the durability time was 100 hours or more and the generation of cracks could be suppressed.

  On the other hand, there is a glass phase at the grain boundary between the two faces, and sample No. In No. 6, cracks occurred in 800 hours.

  A liquid ejecting apparatus can be suitably used for an ink jet printer used for printing. In particular, the liquid flow path member of the present invention can be applied to all ink jet print heads regardless of the heating (bubble generation) method or the piezoelectric actuator method. Furthermore, application to industrial printing machines can also be expected.

1A and 1B show a piezoelectric actuator of the present invention, in which FIG. 1A is a schematic cross-sectional view, FIG. 1B is a schematic cross-sectional view of a piezoelectric actuator joined to a restraining member, and FIG. The crystal structure of the piezoelectric material which comprises the piezoelectric actuator of this invention is shown, (a) is a schematic diagram, (b) is an enlarged view of a part of (a). 1 shows a structure of a liquid ejection device, where (a) is a schematic cross-sectional view and (b) is a plan view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric actuator 2 ... Vibration board 3 ... Restraining member 3a ... Groove 3b ... Partition 4 ... Piezoelectric layer 5 ... Common electrode 6 ... Surface electrode 7 ... Piezoelectric displacement element 7a ... displacement region 7b ... non-displacement region 101 ... main crystal grain 102 ... triple grain boundary 103 ... between crystal grain boundary T ... between crystal Grain boundary thickness

Claims (6)

In the piezoelectric actuator configured by a plurality of displacement regions and a non-displacement region provided so as to surround the displacement regions on the same plane, the grain boundary between the two faces of the main crystal of the piezoelectric layer is substantially glass. A piezoelectric actuator characterized by not containing a phase. A common electrode, a piezoelectric layer, and a surface electrode are laminated in this order on the vibration substrate. A plurality of the surface electrodes are two-dimensionally arranged on the surface of the piezoelectric layer, and a displacement region is formed with the piezoelectric layer. 2. The piezoelectric actuator according to claim 1, comprising: the surface electrode; a portion of the common electrode facing the surface electrode; and a portion of the diaphragm facing the surface electrode. 3. The piezoelectric actuator according to claim 2, wherein the piezoelectric body is made of a perovskite type compound containing lead. 4. The piezoelectric actuator according to claim 2, wherein the piezoelectric body contains Ti and / or Zr. The piezoelectric actuator according to claim 1, wherein the glass phase of the triple point grain boundary contains Si. The piezoelectric device according to any one of claims 1 to 5, wherein a liquid discharge nozzle is provided on one surface, a mounting portion for a piezoelectric actuator is provided on the other surface, and the surface of a flow path member having a liquid flow path therein. A liquid ejecting apparatus comprising an actuator.

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