JP2004357438A - Piezoelectric actuator and ink-jet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric actuator that can highly integrate discrete electrodes, and an ink-jet recording head equipped with the same. <P>SOLUTION: The piezoelectric actuator 11 is constituted such that: a plurality of piezoelectric ceramic layers 13, 13 and 13 on which a plurality of discrete electrodes 12 are electrically insulated and disposed, respectively, and a plurality of ceramic layers 15, 15 and 15 on which common electrodes 14 are formed, respectively, are alternately laminated and formed; the plurality of discrete electrodes 12 that are disposed in almost the same position in the thickness direction are electrically connected via-electrodes 17; a non-electrode part 14a having no electrode at the position where the via-electrode 17 is formed is arranged on the common electrode 14 so that the common electrode 14 is electrically insulated from the via-electrode 17; and the length of the non-electrode part is not shorter than the length of the via-electrode in the same direction of the length of the non-electrode part by 20μm. The ink-jet recording head is equipped with the piezoelectric actuator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４４】
【発明の効果】
本発明の前記圧電アクチュエータによれば、厚み方向に略同一の位置に配置された複数の個別電極間における電気的接続がビア電極を介して施されているので、圧電セラミック層に多数の個別電極を設けて、個別電極を高集積化することができる。また、共通電極には、複数の個別電極を接続するビア電極が形成されている位置に、電極のない非電極部が設けられていることにより共通電極が上記ビア電極と電気的に絶縁されているので、複数の個別電極を接続するビア電極と、共通電極とが短絡（ショート）するのを防止することができる。しかも、非電極部の長さが、これと同方向のビア電極の長さよりも２０μｍ以上大きいので、たとえ電極の印刷位置が少しずれた場合であっても、ビア電極と共通電極とが短絡するのを確実に防止することができる。これにより、高集積化された高品質の圧電アクチュエータおよびこれを備えたインクジェット記録ヘッドを得ることができるという効果がある。
【図面の簡単な説明】
【図１】本発明の一実施形態にかかる圧電アクチュエータを示す断面図である。
【図２】本発明の一実施形態にかかる圧電アクチュエータを示す平面図である。
【図３】図１の一部を拡大した拡大断面図である。
【図４】本発明の圧電アクチュエータにおける共通電極、非電極部およびビア電極の配置状態を示す概略図である。
【図５】本発明の一実施形態にかかるインクジェット記録ヘッドを示す断面図である。
【図６】本発明の他の実施形態にかかる圧電アクチュエータを示す断面図である。
【図７】実施例において作製した圧電アクチュエータにおける個別電極を示す平面図である。
【符号の説明】
１１ 圧電アクチュエータ
１２ 個別電極
１２ａ 駆動部
１２ｂ 非駆動部
１３ 圧電セラミック層
１４ 共通電極
１４ａ 非電極部
１５ 圧電セラミック層
１７ ビア電極
１８ 共通電極用ビア電極
１９ 振動板
２０ 引出電極[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piezoelectric actuator used for positioning and pressing various devices by generating a minute displacement, and an ink jet recording head equipped with the same, and particularly, uses a spreading vibration, an extension vibration, and a vertical vibration. The present invention relates to a piezoelectric actuator and an ink jet recording head suitably used for an ink jet recording head.
[0002]
[Prior art]
Conventionally, products using piezoelectric ceramics include, for example, piezoelectric actuators, filters, piezoelectric resonators (including oscillators), ultrasonic vibrators, ultrasonic motors, and piezoelectric sensors. Among them, the piezoelectric actuator has a very high response speed to an electric signal of the order of 10 ⁻⁶ seconds, and therefore, the piezoelectric actuator for positioning the XY stage of the semiconductor manufacturing apparatus and the piezoelectric actuator used for the print head of the inkjet printer. And so on.
[0003]
For example, in Patent Literature 1, a plurality of piezoelectric ceramic layers in each of which a plurality of individual electrodes are electrically insulated and arranged, and a plurality of piezoelectric ceramic layers in which a common electrode is formed are alternately stacked. Piezoelectric actuators and ink jet recording heads having the same have been proposed. In the piezoelectric actuator and the ink jet recording head, the plurality of individual electrodes disposed at substantially the same position in the thickness direction have a long shape, respectively, and are electrically connected on the side surfaces of the piezoelectric actuator (Patent Document 1). 5 and 6).
[0004]
[Patent Document 1]
5 and 6 of JP-A-2002-225269.
[0005]
[Problems to be solved by the invention]
However, in the piezoelectric actuator described in Patent Literature 1, since a plurality of individual electrodes are electrically connected only on the side surfaces of the piezoelectric actuator, a plurality of individual electrodes cannot be arranged vertically and horizontally. There is a problem that it is difficult to integrate.
[0006]
Accordingly, it is an object of the present invention to provide a piezoelectric actuator capable of highly integrating individual electrodes and an ink jet recording head including the same.
[0007]
[Means for Solving the Problems]
A piezoelectric actuator and an inkjet recording head according to the present invention for solving the above problems have the following configurations.
(1) A piezoelectric actuator formed by alternately laminating a plurality of piezoelectric ceramic layers in which a plurality of individual electrodes are respectively electrically insulated and arranged and a plurality of piezoelectric ceramic layers in which a common electrode is formed. A plurality of individual electrodes arranged at substantially the same position in the thickness direction are electrically connected via a via electrode, and the common electrode is electrically insulated from the via electrode. A non-electrode portion having no electrode is provided at a position where the via electrode is formed, and the length of the non-electrode portion is at least 20 μm larger than the length of the via electrode in the same direction as the non-electrode portion. Piezoelectric actuator.
(2) The individual electrode includes a driving unit that contributes to piezoelectric driving, and a non-driving unit that extends from one end of the driving unit to connect to the via electrode, and the non-electrode unit is configured to drive the non-driving unit. The piezoelectric actuator according to (1), which is arranged at a position facing the portion.
(3) The piezoelectric actuator according to (2), wherein a portion of the non-driving portion facing the non-electrode portion is 50% or more of an area of the non-driving portion.
(4) The piezoelectric actuator according to (2) or (3), wherein the non-electrode portion is disposed at a position not substantially facing the driving portion.
(5) Each common electrode formed on the plurality of piezoelectric ceramic layers is electrically connected to the individual electrode via a common electrode via electrode at a portion electrically insulated from the individual electrode. The piezoelectric actuator according to any one of (1) to (4).
(6) The piezoelectric actuator according to any one of (1) to (5), wherein the ink flow path and the individual electrode are provided on a flow path member having a plurality of ink flow paths having ink discharge ports. An ink jet recording head characterized in that the ink jet recording heads are mounted in the same position.
[0008]
According to the piezoelectric actuator described in the above (1), the electrical connection between the plurality of individual electrodes arranged at substantially the same position in the thickness direction is made via the via electrode. The individual electrodes can be connected in the thickness direction not only at the portions exposed on the side surfaces of the piezoelectric actuator but also inside the piezoelectric actuator. Thus, a large number of individual electrodes can be provided vertically and horizontally on the surface of the piezoelectric ceramic layer, and the individual electrodes can be highly integrated. In addition, the common electrode is electrically insulated from the via electrode by providing a non-electrode portion having no electrode at a position where a via electrode connecting a plurality of individual electrodes is formed. Therefore, a short circuit between the via electrode connecting the plurality of individual electrodes and the common electrode can be prevented. In addition, since the length of the non-electrode portion is larger than the length of the via electrode in the same direction by 20 μm or more, the via electrode and the common electrode are short-circuited even if the printing position of the electrode is slightly shifted. Can be reliably prevented. Here, the “length of the non-electrode portion, the length of the via electrode” means a dimension in any direction (vertical direction, horizontal direction) except for the thickness, or a diameter in the case of a circle.
[0009]
According to the piezoelectric actuators described in (2) and (3), since the non-electrode portion is disposed at a position facing the non-drive portion, unnecessary piezoelectric driving of the piezoelectric ceramic layer immediately below the non-drive portion is performed. Can be suppressed. This can reduce the influence of the non-driving section on the displacement of the piezoelectric displacement section formed by the driving section, the piezoelectric ceramic layer immediately below the driving section, and the common electrode. Since the influence (so-called crosstalk) can also be reduced, it is possible to suppress a decrease in the displacement amount of the piezoelectric displacement unit and to stabilize the displacement of the piezoelectric displacement unit.
[0010]
According to the piezoelectric actuator described in (4), since the non-electrode portion is disposed at a position not substantially facing the driving portion, the driving portion can efficiently contribute to the piezoelectric driving. Here, “substantially not facing” described in the above (4) means that the non-electrode portion does not face most or all regions of the driving portion. That is, when the non-electrode portion is projected from the thickness direction of the piezoelectric actuator onto a plane where the drive portion exists, it means that the non-electrode portion does not overlap most or all of the region of the drive portion.
[0011]
According to the piezoelectric actuator described in (5), since the common electrode is electrically connected via the via electrode, the via electrode for the common electrode is formed when the via electrode connecting the plurality of individual electrodes is formed. Can also be formed at the same time. Accordingly, it is not necessary to separately increase the number of manufacturing steps for connecting the common electrode, and the steps can be simplified, the production efficiency can be improved, and the cost can be prevented.
[0012]
According to the above (6), since the above-described piezoelectric actuator having the highly integrated individual electrodes is provided, it is possible to obtain an ink jet recording head having a large number of ink ejection holes arranged vertically and horizontally. it can.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a piezoelectric actuator according to an embodiment of the present invention and an ink jet recording head including the same will be described in detail with reference to the drawings.
[0014]
FIG. 1 is a sectional view showing a piezoelectric actuator according to the present embodiment, and FIG. 2 is a plan view thereof. FIG. 3 is an enlarged sectional view showing the piezoelectric actuator. As shown in FIGS. 1 to 3, the piezoelectric actuator 11 includes a plurality of piezoelectric ceramic layers 13, 13, 13 in which a plurality of individual electrodes 12 are arranged in a state of being electrically insulated, and a common electrode 14. The plurality of piezoelectric ceramic layers 15, 15, 15 are alternately laminated. A diaphragm 19 is laminated below the lowermost piezoelectric ceramic layer 15.
[0015]
The individual electrode 12 includes a driving unit 12a that contributes to piezoelectric driving, and a non-driving unit 12b that extends from one end of the driving unit 12a. The plurality of individual electrodes 12 arranged at substantially the same position in the thickness direction are electrically connected via the via electrodes 17 in the non-driving section 12b. A drive circuit for supplying an oscillating voltage signal is connected to the uppermost non-driving section 12b via a wiring board (not shown).
[0016]
In the common electrode 14, a non-electrode portion 14a having no electrode is provided at a position where a via electrode 17 connecting the plurality of individual electrodes 12 is formed. Thereby, the common electrode 14 is electrically insulated from the via electrode 17. The plurality of common electrodes 14 are electrically connected via a common electrode via electrode 18 at an end of the piezoelectric actuator 11 which is a part electrically insulated from the individual electrodes 12. The via electrode 18 is electrically connected to an extraction electrode 20 formed on the uppermost piezoelectric ceramic layer 13 and is further connected to a ground potential. Thereby, a voltage can be applied between the drive unit 12 a of the individual electrode 12 and the common electrode 14. By applying a voltage in this manner, a plurality of piezoelectric displacement portions formed by the driving portion 12a, the piezoelectric ceramic layer 13 immediately below the driving portion 12a, and the common electrode 14 can be subjected to piezoelectric vibration.
[0017]
FIG. 4 is a schematic diagram showing an arrangement state of the common electrode 14, the non-electrode portion 14a, and the via electrode 17. As shown in FIG. 4, the length L1 of the non-electrode portion 14a is larger than the length L2 of the via electrode 17 in the same direction by 20 μm or more, preferably 30 μm or more, and more preferably 40 to 300 μm. . If the difference (L1−L2) between L1 and L2 is less than 20 μm, the common electrode 14 and the via electrode 17 may be short-circuited. The lengths of the via electrodes 17 and 18 may be set according to the size of the non-electrode portion 14a, the drive portion 12a, the extraction electrode 20, and the like, and are not particularly limited, but are usually 100 to 400 μm, preferably 150 to 250 μm. It is good.
[0018]
The non-electrode portion 14a is preferably disposed at a position not substantially facing the driving portion 12a, that is, at a position not facing most or all of the driving portion 12a. Specifically, the non-electrode portion 14a preferably has a portion occupying 70% or more of the area of the driving portion 12a, more preferably a portion occupying 90% or more of the area of the driving portion 12a, and still more preferably the entirety of the driving portion 12a. It is preferable to be arranged at a position not facing the region. Thereby, the driving unit 12a can efficiently contribute to the piezoelectric driving.
[0019]
The non-electrode portion 14a is preferably disposed at a position facing the non-drive portion 12b. Preferably, the non-drive portion 12b has a portion facing the non-electrode portion 14a having an area of 50% of the non-drive portion 12b. %, More preferably 70% or more, even more preferably 90% or more. Accordingly, it is possible to reduce the influence of the non-drive unit 12b on the displacement of the piezoelectric displacement unit formed by the drive unit 12a, the piezoelectric ceramic layer 13 immediately below the drive unit 12a, and the common electrode 14. it can. In addition, the influence (crosstalk) of the non-driving section 12b on the adjacent piezoelectric displacement section can be reduced.
[0020]
As the piezoelectric ceramic layers 13 and 15, a perovskite crystal structure type material such as a lead zirconate titanate compound, a lead titanate compound, and a barium titanate compound is preferably used. Among these, a PbZrTiO ₃ -based compound (PZT) is particularly preferable in that a large displacement can be obtained. The thickness of the piezoelectric ceramic layers 13 and 15 is not particularly limited, but is preferably 30 μm or less, preferably 20 μm or less, and more preferably 8 to 15 μm.
[0021]
The diaphragm 19 may be a material having a high insulating property, but is preferably a piezoelectric material, particularly preferably a material having substantially the same coefficient of thermal expansion as the piezoelectric ceramic layers 13 and 15. More preferably, the composition is substantially the same as 15. Thereby, simultaneous firing becomes possible, and it becomes easy to prevent warpage and distortion from occurring due to thermal stress generated during firing due to a difference in thermal expansion. The thickness of the diaphragm 19 is not particularly limited, but is preferably 80 μm or less, preferably 60 μm or less, and more preferably 20 to 50 μm. The total thickness of the piezoelectric actuator 11 is 400 μm or less, preferably 200 μm or less, and more preferably 60 to 150 μm.
[0022]
The porosity of the piezoelectric ceramic layers 13 and 15 and the diaphragm 19 is preferably 1% or less, particularly 0.8% or less, and more preferably 0.5% or less, so that penetration of a liquid such as ink can be effectively prevented. This is preferable since ink leakage can be reduced.
[0023]
The material of the individual electrode 12, the common electrode 14, the via electrodes 17, 18 and the extraction electrode 20 may be any material as long as it has conductivity, and may be Au, Ag, Pd, Pt, Cu, Al, Rh, Ni-based material. An alloy or a combination of two or more of these is used. In particular, it is preferable to use an Ag-Pd-based alloy as the common electrode 14, and it is preferable to use Au as the individual electrode 12 in terms of excellent electric resistance and corrosion resistance. It is preferable that the driving portion 12a and the non-driving portion 12b of the individual electrode 12 be formed simultaneously with the same material.
[0024]
The thickness of the common electrode 14 is preferably such that it has conductivity and does not hinder displacement, and is preferably 0.5 to 8 μm, and more preferably 1 to 3 μm. The thickness of the individual electrode 12 is 0.3 to 5 μm, preferably 0.5 to 2 μm.
[0025]
The material of the non-electrode portion 14a in the present invention is a non-electrode material in which the piezoelectric ceramic layers located above and below the non-electrode portion 14a do not undergo piezoelectric vibration when a voltage is applied between the individual electrode 12 and the common electrode 14. It is not particularly limited. For example, examples of the non-electrode material include an insulating material such as alumina and silicon nitride, and a piezoelectric material such as a lead zirconate titanate compound, a lead titanate compound, and a barium titanate compound. In particular, it is preferable that the non-electrode portion 14a is formed of the same piezoelectric material as the piezoelectric ceramic layers 13 and 15 in that the shrinkage during firing is made uniform.
[0026]
Next, a method for manufacturing the piezoelectric actuator 11 will be described. First, after forming a required number of green sheets using the above-described piezoelectric ceramic powder, through holes for via electrodes 17 and 18 are formed in the green sheets.
[0027]
Next, the green sheet having the through-hole formed therein is filled with a conductor serving as a via electrode by screen printing, and a common electrode pattern, an individual electrode pattern, and an extraction electrode pattern are formed on the corresponding green sheet. At this time, an opening for forming the non-electrode portion 14a is formed in the common electrode pattern at a position facing the non-drive portion 12b shown in FIG. In order to form the opening, the common electrode paste may be printed without providing an opening at a location corresponding to the opening in the screen plate for forming the common electrode pattern. As a result, the common electrode paste is not printed on the portion corresponding to the opening.
[0028]
Next, the green sheets obtained as described above are laminated so as to have the configuration shown in FIG. 1 to produce a laminate. A non-electrode portion 14a without an electrode is formed in the obtained laminate. The non-electrode portion 14a may be filled with a non-electrode material such as a piezoelectric material as described above, but is preferably filled with the same piezoelectric material as the piezoelectric ceramic layers 13 and 15. As a method of filling the non-electrode portion 14a with the non-electrode material, the following two methods can be exemplified.
[0029]
In the first method, the non-electrode portion 14a is formed by filling the opening with a piezoelectric material that becomes the piezoelectric ceramic layer 13 after firing. Therefore, the non-electrode portion 14a is an integrated product that is continuous with the piezoelectric ceramic layer 13.
[0030]
In the second method, after forming the common electrode pattern on the surface of the piezoelectric ceramic layer 15, the non-electrode portion 14 a is filled in advance with a non-electrode material having substantially the same thickness as the common electrode pattern in the opening by screen printing or the like. After that, the respective piezoelectric ceramic layers are laminated.
[0031]
The piezoelectric actuator 11 can be obtained by cutting the laminated body obtained as described above into a predetermined shape and baking it at about 900 to 1100 ° C.
[0032]
Next, the ink jet recording head of the present invention will be described. In the ink jet recording head shown in FIG. 5, the piezoelectric actuator 11 is provided on a flow path member 51 in which a plurality of ink flow paths 53 having ink discharge ports 52 are arranged. Are mounted in the same position.
[0033]
The flow path member 51 is obtained by a rolling method or the like, and the ink discharge holes 52 and the ink flow paths 53 are formed into a predetermined shape by etching. The flow path member 51 is desirably formed of at least one selected from the group of Fe-Cr-based, Fe-Ni-based, and WC-TiC-based, and is preferably made of a material having excellent corrosion resistance to ink. Desirably, the Fe-Cr system is more preferable.
[0034]
The piezoelectric actuator 11 and the flow path member 51 can be laminated and bonded via an adhesive layer, for example. As the adhesive layer, a well-known adhesive layer can be used, but in order not to affect the piezoelectric actuator 11 and the flow path member 51, an epoxy resin, a phenol resin, and a polyphenylene ether having a thermosetting temperature of 130 to 250 ° C. It is preferable to use at least one thermosetting resin-based adhesive selected from the group of resins. By heating to the thermosetting temperature using such an adhesive layer, the piezoelectric actuator 11 and the flow path member 51 can be heat-bonded, whereby an ink jet recording head can be obtained.
[0035]
<Other embodiments>
FIG. 6 is a sectional view showing a piezoelectric actuator according to another embodiment of the present invention. As shown in FIG. 6, in the piezoelectric actuator 11 ', a non-electrode portion is not provided on the lowermost common electrode 14'. Since the via electrode 17 connecting the plurality of individual electrodes 12 does not extend to the lowermost common electrode 14 ′, the common electrode and the individual electrode can be connected to each other without providing a non-electrode portion on the common electrode 14 ′. Never short-circuit. However, like the piezoelectric actuator 11 shown in FIG. 1, the lowermost common electrode 14 is also provided with the non-electrode portion 14a at the same position as the uppermost and second-layer common electrodes 14, so that the lowermost layer can be formed. Unnecessary piezoelectric driving of the piezoelectric ceramic layer 13 immediately below the non-driving portion 12b can be suppressed.
[0036]
Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above-described embodiments, but can be applied to modified or improved ones without departing from the gist of the present invention.
[0037]
For example, the shapes of the driving unit, the non-driving unit, the non-electrode unit, the via electrode, and the like, the number of stacked piezoelectric ceramic layers, the common electrode, and the like are not particularly limited, and may be appropriately adjusted as needed.
[0038]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.
[0039]
A plurality of piezoelectric ceramic layers mainly composed of lead zirconate titanate, on which individual electrodes of Example Au having a thickness of 1 μm are arranged, and a common electrode having a thickness of 2 μm made of an Ag—Pd alloy are formed. A piezoelectric actuator 11 having a configuration as shown in FIG. 1 in which a plurality of piezoelectric ceramic layers containing lead zirconate as a main component were alternately laminated (sample Nos. 1 to 8). Ag-Pd was used as the material of the via electrodes 17 and 18, and Au was used as the material of the extraction electrode 20.
[0040]
FIG. It is a top view which shows the individual electrode 12 provided in 1-8 piezoelectric actuators 11. FIG. The individual electrode 12 had a horizontal length L3 of the non-driving portion 12b of 250 μm and a vertical length L4 of 800 μm. The length (diameter) L2 of the via electrode 17 was 200 μm.
[0041]
The length of the non-electrode portion 14a of each sample was a value shown in Table 1. Sample No. Each of the non-electrode portions 14a of Nos. 1 to 4 has a circular planar shape. The planar shapes of the non-electrode portions 14a of 5 to 8 were rectangular. Table 1 shows these lengths. Table 1 also shows the area ratio of the non-drive portion 12b occupied by the portion facing the non-electrode portion. This area ratio was changed by adjusting the formation position of the non-electrode portion 14a when the common electrode 14 was formed.
[0042]
<Performance confirmation test>
By applying a voltage to the common electrode 14 and the individual electrode 12 of each sample, it was confirmed whether the non-electrode portion 14a and the via electrode 17 connected to the individual electrode 12 were short-circuited (short-circuited). As a result, no short circuit occurred in the samples 3 to 8 in which the length of the non-electrode portion 14a was larger than the length of the via electrode 17 by 20 μm or more, but the difference between the length of the non-electrode portion 14a and the length of the via electrode 17 was small. Samples 1 and 2 having a size of less than 20 μm were short-circuited.
[0043]
Next, the amount of displacement when a voltage was applied to the common electrodes 14 and the individual electrodes 12 of the samples 1 to 8 was measured by a laser Doppler vibrometer. In addition, the displacement amount A shown in Table 1 is a displacement amount when only the piezoelectric displacement portion to be measured is driven, and the displacement amount B is not limited to the piezoelectric displacement portion to be measured. This is the displacement amount when the eight piezoelectric displacement units disposed around the periphery are simultaneously driven. The reduction rate of the displacement shown in Table 1 was calculated by dividing the difference between the displacement A and the displacement B by the displacement A and multiplying the difference by 100. As a result, although the decrease in the displacement was relatively small for each sample, it was confirmed that the decrease in the displacement was very small and the crosstalk was less susceptible, especially when the area ratio was 50% or more. Was.
[Table 1]

[0044]
【The invention's effect】
According to the piezoelectric actuator of the present invention, the electrical connection between the plurality of individual electrodes arranged at substantially the same position in the thickness direction is made via the via electrode. Is provided, the individual electrodes can be highly integrated. In addition, the common electrode is electrically insulated from the via electrode by providing a non-electrode portion having no electrode at a position where a via electrode connecting a plurality of individual electrodes is formed. Therefore, a short circuit between the via electrode connecting the plurality of individual electrodes and the common electrode can be prevented. In addition, since the length of the non-electrode portion is larger than the length of the via electrode in the same direction by 20 μm or more, the via electrode and the common electrode are short-circuited even if the printing position of the electrode is slightly shifted. Can be reliably prevented. Thus, there is an effect that a highly integrated high quality piezoelectric actuator and an ink jet recording head including the same can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a piezoelectric actuator according to one embodiment of the present invention.
FIG. 2 is a plan view showing a piezoelectric actuator according to one embodiment of the present invention.
FIG. 3 is an enlarged sectional view in which a part of FIG. 1 is enlarged.
FIG. 4 is a schematic view showing an arrangement state of a common electrode, a non-electrode portion, and a via electrode in the piezoelectric actuator of the present invention.
FIG. 5 is a cross-sectional view illustrating an inkjet recording head according to an embodiment of the present invention.
FIG. 6 is a sectional view showing a piezoelectric actuator according to another embodiment of the present invention.
FIG. 7 is a plan view showing individual electrodes in a piezoelectric actuator manufactured in an example.
[Explanation of symbols]
Reference Signs List 11 piezoelectric actuator 12 individual electrode 12a drive unit 12b non-drive unit 13 piezoelectric ceramic layer 14 common electrode 14a non-electrode unit 15 piezoelectric ceramic layer 17 via electrode 18 common electrode via electrode 19 diaphragm 20 extraction electrode

Claims (6)

A piezoelectric actuator formed by alternately stacking a plurality of piezoelectric ceramic layers in which a plurality of individual electrodes are respectively electrically insulated and arranged, and a plurality of piezoelectric ceramic layers in which a common electrode is formed,
A plurality of individual electrodes arranged at substantially the same position in the thickness direction are electrically connected via a via electrode, and the common electrode is configured such that the common electrode is electrically insulated from the via electrode. A non-electrode portion having no electrode is provided at a position where the via electrode is formed, and the length of the non-electrode portion is larger than the length of the via electrode in the same direction by 20 μm or more. Actuator. The individual electrode includes a driving unit contributing to piezoelectric driving, and a non-driving unit extending from one end of the driving unit to connect to the via electrode, wherein the non-electrode unit faces the non-driving unit. The piezoelectric actuator according to claim 1, wherein the piezoelectric actuator is disposed at a position where the piezoelectric actuator moves. 3. The piezoelectric actuator according to claim 2, wherein a portion of the non-driving portion facing the non-electrode portion is 50% or more of an area of the non-driving portion. 4. The piezoelectric actuator according to claim 2, wherein the non-electrode portion is disposed at a position that does not substantially face the driving portion. The common electrodes formed on the plurality of piezoelectric ceramic layers are electrically connected via common electrode via electrodes at portions that are electrically insulated from the individual electrodes. The piezoelectric actuator according to any one of the above. 6. The piezoelectric actuator according to claim 1, wherein the ink flow path and the individual electrode are aligned on a flow path member having a plurality of ink flow paths having ink discharge ports. An ink jet recording head characterized in that:

Images