JP5444606B2 - Laminated body for piezoelectric actuator, manufacturing method thereof, and piezoelectric actuator - Google Patents

Description

  The present invention relates to a piezoelectric actuator used for an inkjet head or the like, a laminate for a piezoelectric actuator for manufacturing the piezoelectric actuator, and a method for manufacturing the same.

  An inkjet head that transports ink supplied from an ink tank and ejects ink droplets from a nozzle toward a recording sheet or the like is already known. This inkjet method is classified according to the difference in the generation method of the ejection energy, and the ink droplet is ejected by the generation of bubbles by the thermal energy and the piezoelectric method that ejects the ink droplet by using the vibration force of the piezoelectric element. There is a thermal jet system to be used.

  A piezoelectric inkjet head includes a flow path unit in which a plurality of pressure chambers corresponding to each nozzle are provided in a flow path from a common liquid chamber connected to an ink supply port to a plurality of nozzles, and the flow path unit above the flow path unit. And a piezoelectric actuator that is bonded to selectively change the volume of the pressure chamber. Among these, the piezoelectric actuator has a configuration in which an internal electrode portion is sandwiched between layers of a plurality of stacked piezoelectric layers.

  In the manufacturing process of the piezoelectric actuator, a plurality of green sheets are fired to form a stacked piezoelectric layer, but the pitch of the internal electrodes due to the stacking deviation of the green sheets or the contraction of the green sheets. It happens that the change is different from the design value. Therefore, when the piezoelectric actuator and the flow path unit are combined, there has been a problem that the internal electrode portion and the pressure chamber are not accurately matched.

Therefore, in the piezoelectric actuator of Patent Document 1, positioning marks are provided at the four corners of the piezoelectric layer on which the internal electrode portion is formed, and light is applied in the stacking direction after firing to determine the joining reference point with the flow path unit. Thus, the positions of the internal electrode portion and the pressure chamber are made to correspond accurately.
JP 2003-112423 A

  However, in addition to the above-described problem, there is a problem of positional displacement between the internal individual electrode and the surface individual electrode connected to the internal individual electrode due to a deviation from the design value due to the above-described green sheet stacking deviation or the pitch change of the internal individual electrodes.

  Here, the positioning mark provided on the piezoelectric actuator described in Patent Document 1 is for preventing the displacement with respect to the flow path unit, and the positional displacement between the internal individual electrode and the surface individual electrode. It is not something to detect. Even if an attempt is made to detect the same positional deviation using the positioning marks, the positioning marks are provided only at the four corners, so that the positions of the internal individual electrodes and the surface individual electrodes cannot be accurately aligned.

  Therefore, in view of the above-described problems of the prior art, the present invention provides a piezoelectric actuator laminate capable of accurately aligning the position of a surface individual electrode and an internal electrode (for example, an internal individual electrode) formed between piezoelectric layers, An object of the present invention is to provide a manufacturing method thereof and a piezoelectric actuator.

  In order to achieve the above object, the present invention takes the following technical means.

That is, the multilayer body for a piezoelectric actuator of the present invention includes a plurality of stacked piezoelectric layers, a first electrode layer formed between two piezoelectric layers adjacent in the stacking direction among the plurality of piezoelectric layers, and the two One of the piezoelectric layers, and a second electrode layer formed between the other piezoelectric layers other than the two piezoelectric layers, and one outer surface of the plurality of stacked piezoelectric layers Is a laminate for a piezoelectric actuator to be a surface on which a plurality of individual surface electrodes are provided,
An electrode terminal extends from each surface individual electrode, and the first electrode layer has a plurality of internal electrodes arranged at positions corresponding to the plurality of surface individual electrodes in a plan view. A small hole is formed in each of the internal electrodes, and the second electrode layer covers the overlapping hole formed at least partially overlapping each of the plurality of internal electrodes in plan view, and the small hole A transmission part that is a slit ,
Each of the electrode terminals overlaps with each of the small holes in plan view.

  According to the laminated body for piezoelectric actuators of the present invention, a small hole is formed in the internal electrode of the first electrode layer, and the second electrode layer has a transmission part where the electrode part does not exist at the position overlapping the small hole. When light is applied in the stacking direction, the position of the small hole can be confirmed through the transmission part. Thereby, the position of the internal electrode can be detected in relation to the position of the small hole.

  Further, an extension portion that does not overlap the individual surface electrodes in plan view may be formed in each internal electrode, and the small holes may be formed in the extension portions.

  In this case, the small holes can be formed at positions that do not overlap the surface individual electrodes.

Further, it is preferable that the plurality of internal electrodes are formed in a row, and each extension portion is formed between two adjacent internal electrodes.
In this case, the extension can be arranged by effectively using the space between the two rows of internal electrodes.
As one form of the piezoelectric actuator laminate, for example, the plurality of internal electrodes of the first electrode layer are first constant potential electrodes to which a constant potential is applied, and the second electrode layer The electrode is a second constant potential electrode to which a potential different from the potential of the first constant potential electrode is applied. By applying a first potential to each surface individual electrode, each surface individual electrode and the first constant potential electrode are applied. A first active portion is formed between the surface individual electrode and a second potential is applied to each surface individual electrode, whereby a second active portion is formed between each surface individual electrode and the second constant potential electrode layer. What forms a part is mentioned.
The piezoelectric actuator manufacturing method of the present invention is a method of manufacturing a piezoelectric actuator in which a plurality of individual surface electrodes are provided on the one outer surface of the piezoelectric actuator laminate, and the piezoelectric actuator laminate is laminated on the piezoelectric actuator laminate. The position of each small hole is confirmed by applying light from the direction, the position of each internal electrode is detected from the position of each small hole, and the position of each internal electrode is determined based on the position information of each internal electrode. A plurality of surface electrodes are formed on the one outer surface so as to match each other.

  According to the method for manufacturing a piezoelectric actuator of the present invention, the position of each internal electrode is detected by irradiating light in the stacking direction, and the position of each internal electrode and each surface individual electrode is aligned to be stacked for the piezoelectric actuator. Since each surface individual electrode is formed on the body, a piezoelectric actuator in which the positions of each internal electrode and each surface individual electrode are accurately matched can be obtained.

The piezoelectric actuator of the present invention includes a plurality of stacked piezoelectric layers, a first electrode layer formed between two piezoelectric layers adjacent to each other in the stacking direction, and the two piezoelectric layers. A piezoelectric actuator comprising: a second electrode layer formed between one piezoelectric layer and another piezoelectric layer; and a plurality of individual electrodes provided on one outer surface of the plurality of stacked piezoelectric layers. And
The first electrode layer has a plurality of internal electrodes arranged at positions corresponding to the plurality of individual electrodes in plan view, and a small hole is formed in each of the plurality of internal electrodes,
The second electrode layer has an overlapping electrode portion formed so as to at least partially overlap each of the plurality of internal electrodes in a plan view, and a transmission portion that is a slit that covers the small hole,
On one outer surface of the plurality of piezoelectric layers, a plurality of electrode terminals for connecting to the drive side terminal electrode of the wiring member are provided so as to extend from the plurality of individual electrodes, respectively.
Each of the electrode terminals overlaps with each of the small holes in plan view.

According to the piezoelectric actuator of the present invention, a small hole is formed in the internal electrode of the first electrode layer, and the second electrode layer has a transmission part where the electrode part does not exist at a position overlapping the small hole. When light is applied in the stacking direction, the position of the small hole can be confirmed through the transmission part, and the position of the internal electrode can be detected in relation to the position of the small hole.
Further, even after the surface individual electrode is formed, the positional deviation between the surface individual electrode and the internal electrode can be confirmed by applying light in the stacking direction. Thereby, the quality of a product can be improved by selecting only the product without the same position shift.
In addition, when the piezoelectric actuator is applied to a piezoelectric actuator for an inkjet head that is bonded to a flow path unit having a plurality of pressure chambers and selectively changes the volume of the plurality of pressure chambers, On one outer surface of the piezoelectric layer, a plurality of electrode terminals for joining to the drive-side terminal electrodes of the wiring members are provided so as to extend from the plurality of individual electrodes, respectively, and each of the internal electrodes is viewed in plan view. In addition, each of the surface individual electrodes has an extension portion that does not overlap with each other, each of the small holes is formed in the extension portion, and each of the electrode terminals overlaps with each of the small holes in a plan view. preferable.
In this case, there should be no stray capacitance between the electrode terminal necessary for connecting the individual electrode to the wiring and the extension necessary for providing a small hole for detecting the position of the internal electrode. can do.

  As described above, according to the present invention, since the position of the internal electrode can be known by applying light in the stacking direction, the positions of the surface individual electrode and the internal individual electrode formed between the piezoelectric layers are accurately aligned. be able to.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of an inkjet head 2 in which the piezoelectric actuator 1 according to the first embodiment of the present invention is used. The ink-jet head 2 is mainly composed of a flow path unit 3 in which a plurality of substantially rectangular plates are laminated, and a piezoelectric actuator 1 joined to the flow path unit 3. A wiring member 4 that outputs driving power for the piezoelectric actuator 1 is joined to the piezoelectric actuator 1. In the following description, as indicated by the arrows in FIG. 1, the long side direction of the flow path unit 3 is the X direction, and the short side direction is the Y direction.

  The ink jet head 2 is provided in an ink jet printer (not shown) that performs ink jet recording and printing on a recording medium such as recording paper. An ink jet printer is provided with a carriage that can reciprocate in a predetermined scanning direction, and an ink jet head is mounted on the carriage. Recording is performed on the recording medium by ejecting ink toward the recording medium while the inkjet head reciprocates in the scanning direction together with the carriage.

FIG. 2 is a cross-sectional view taken along the line II of FIG. The flow path unit 3 is configured by laminating a nozzle plate, a spacer plate, a damper plate, a manifold plate, a supply plate, a base plate 5 and a cavity plate 6 which are formed in a rectangular shape in plan view. Although details are omitted, the plates are laminated to form channels or channels through which ink is circulated by forming communication holes or grooves.

  The piezoelectric actuator 1 includes a top layer 7, an intermediate layer 8, and a bottom layer 9 made of a piezoelectric body, a surface individual electrode 10 (individual electrode) formed on the upper surface (outer surface) of the top layer 7, An internal common electrode 11 (first electrode layer; VDD electrode) formed between the intermediate layer 8 and an external common electrode 12 (second electrode layer) formed between the intermediate layer 8 and the bottom layer 9. A GND electrode). In a state where the piezoelectric actuator 1 is bonded to the flow path unit 3, each pressure chamber 13 of the flow path unit 3 is covered with the bottom layer 9.

  3 is a plan view of the top layer 7, FIG. 4 is a plan view of the intermediate layer 8, and FIG. 5 is a plan view of the bottom layer 9. On the top surface of the top layer 7, eight rectangular surface individual electrodes 10 are arranged in a row. The arrangement state of the surface individual electrodes 10 every two rows from the end is staggered along the column direction. Furthermore, electrode terminals 14 connected to the individual surface electrodes 10 are formed on the upper surface of the top layer 7 so as to extend from the individual surface electrodes 10. These electrode terminals 14 are formed directly beside the individual surface electrodes in the gaps between the individual surface electrodes 10 in every two rows. The electrode terminal 14 is joined to a drive-side terminal electrode of a wiring member provided on the top surface of the top layer.

  On the upper surface of the intermediate layer 8, an internal common electrode 11 is formed over substantially the whole. The internal common electrode 11 has a plurality of internal electrode portions 15 (internal electrodes) at positions corresponding to the individual surface electrodes 10 of the top layer 7 in the stacking direction. And each internal electrode part 15, each pressure chamber 13, and each surface individual electrode 10 have overlapped in the lamination direction (refer FIG. 2).

  Between the internal electrode portions 15 adjacent in the column direction, the non-electrode portions 16 are formed in a rectangular shape. Furthermore, a plurality of small holes 17 are formed in each of the internal electrode portions 15 in rows. Each small hole 17 is formed corresponding to each internal electrode portion 15 with a gap between the internal electrode portions 15 every two rows from the end.

  More specifically, the internal electrode portion 15 includes a main portion adjacent to the non-electrode portion 16 in the column direction and an extension portion extending from one end of the main portion, and a small hole 17 is formed in the extension portion. It has become. Since the main portion overlaps with the surface individual electrode 10 and the extended portion does not overlap with the surface individual electrode 10, the small hole 17 does not overlap with the surface individual electrode 10 as described later.

  On the upper surface of the bottom layer 9, an external common electrode 12 is formed over the entire area. The external common electrode 12 includes an overlapping electrode portion 12 a that overlaps each internal electrode portion 15 in the stacking direction, and a transmission portion 19 that does not have an electrode at a position overlapping each small hole 17. The transmission part 19 includes four slits 20. Each slit 20 has a size capable of covering all the adjacent two rows of small holes 17 formed in the internal common electrode 11 and is formed so as to overlap the two rows of small holes 17 in the stacking direction. ing.

  FIG. 6 is a plan view of the main part of the piezoelectric actuator 1. The external common electrode 12, the internal electrode portion 15, and the surface individual electrode 10 overlap each other in the stacking direction. The individual surface electrode 10 is formed with a size larger than that of the internal electrode portion 15 and protrudes from the internal electrode portion 15 in the vertical direction of FIG. The electrode terminal 14 is in contact with the side end of the surface individual electrode 10. Since each small hole 17 is formed in the gap between the internal electrode portions 15 every two rows from the end as described above, it does not overlap with the surface individual electrode 10 in the stacking direction. Each small hole 17 is located obliquely outside the corner of each internal electrode portion. Moreover, the mutual positional relationship of the small holes 17 every two rows from the end is staggered along the column direction. Thus, since each electrode terminal 14 and each small hole 17 are arranged without waste, even if each small hole 17 is formed, the piezoelectric actuator 1 is not enlarged.

  The slits 20 overlap at the positions of all the small holes 17 in the stacking direction so that the positions of the small holes 17 can be confirmed when light is applied to the piezoelectric actuator from the stacking direction (see FIG. 7). . Therefore, the position of the internal electrode portion 15 can be detected from the positional relationship between each small hole 17 and the internal electrode portion 15.

  Next, how the piezoelectric actuator 1 changes the volume of the pressure chamber 13 of the flow path unit 3 will be described. The piezoelectric actuator 1 includes a first active portion 21 corresponding to the central portion of the pressure chamber 13 in the stacking direction and a second active portion 22 corresponding to the peripheral side of the pressure chamber 13 (FIG. 2). reference).

  Among these, the first active part 21 is constituted by the top layer 7 sandwiched between the individual surface electrode 10 and the internal electrode part 15 provided for each pressure chamber 13. The second active portion 22 is configured by the top layer 7 and the intermediate layer 8 sandwiched between the surface individual electrode 10 and the external common electrode 12 except for the region of the internal electrode portion 15.

  In order to change the volume of each pressure chamber 13, a first potential (ground potential) and a different second potential (for example, 20V) are selectively applied to the surface individual electrode 10 through the wiring member. Further, the first common potential (ground potential) is always applied to the external common electrode 12, and the second potential (for example, 20V) is always applied to the internal electrode portion 15. The piezoelectric actuator 1 selectively applies a first potential (ground potential) and a second potential (for example, 20 V) as drive signals to the surface individual electrode 10, so that the first active portion 21 and the second active portion 21 are activated. The portion 22 can be switched and deformed. Thereby, the piezoelectric actuator 1 changes the volume of the pressure chamber 13.

  Next, a method for manufacturing the piezoelectric actuator 1 will be described. As raw materials for the piezoelectric layer, three green sheets are prepared by spreading a mixture of a mixture of ceramic powder of a lead zirconate titanate (PZT) having ferroelectricity, a binder, and a solvent and drying it. On each green sheet, a conductive material (silver-palladium conductive paste) to be each electrode is printed by screen printing, and the first sheet to be the top layer 7, the second sheet to be the intermediate layer 8, and the bottom layer A third sheet of 9 is produced. The bottom layer may be a diaphragm made of a metal plate such as SUS.

  The second sheet is laminated on the third sheet, and the first sheet is further laminated thereon and sintered to form a piezoelectric actuator laminate 23 (hereinafter referred to as a laminate). Light is applied to the stacked body 23 from the stacking direction. The applied light passes through each piezoelectric layer but does not pass through the electrodes. In the laminate 23 of the present embodiment, a plurality of small holes 17 are formed in the internal common electrode 11, and slits 20 are formed at positions overlapping the small holes 17 in the stacking direction of the external common electrode 12. When light is applied to the body 23 from the stacking direction, the light passes through each small hole 17.

  Therefore, the position of each small hole 17 can be confirmed. The position of each small hole 17 corresponds to the position of each internal electrode portion 15. Thereby, the position of each internal electrode part 15 is detectable even after the laminated body 23 is shape | molded. Based on the position information of the internal electrode portions 15, a plurality of individual surface electrodes are formed on one outer surface of the multilayer body by screen printing so as to be aligned with the internal electrode portions 15.

  Thereafter, a high voltage for polarization treatment is applied between the individual surface electrode 10 and the internal electrode portion 15 and between the individual surface electrode 10 and the external common electrode 12, and the ceramic sheet sandwiched between both electrodes is subjected to the polarization treatment. Thus, piezoelectric characteristics are imparted. Finally, electrode terminals are formed on the top surface of the top layer 7 by screen printing to obtain the piezoelectric actuator 1. In addition, description of the relay electrode, relay wiring, etc. which are conducted to the internal electrode portion and the common electrode in the manufacturing method described above is omitted.

  According to the method of manufacturing the piezoelectric actuator 1 using the laminate 23 of the present embodiment, the small holes 17 corresponding to the internal electrode portions 15 are formed, and the light transmitted through the small holes 17 in the external common electrode 12 is transmitted. Since the slit 20 is formed at a position where it is not blocked, the position of the internal electrode portion 15 can be detected from the position of the small hole 17 when light is applied from one side. And since each surface individual electrode 10 can be formed in the state which confirmed the position of each internal electrode part 15, the piezoelectric actuator 1 in which the position of each internal electrode part 15 and each surface individual electrode 10 in the lamination direction matched was obtained. be able to.

  Furthermore, according to the piezoelectric actuator 1 of the present embodiment, after the piezoelectric actuator 1 is completed, the position of each internal electrode portion 15 and each surface individual electrode 10 is confirmed by reconfirming the position of each internal electrode portion 15. Can be selected. Thereby, the quality of the piezoelectric actuator 1 can be improved. Further, the piezoelectric actuator 1 of the present embodiment is manufactured without confirming the position of the internal electrode portion 15 in the manufacturing process, and the positional deviation data of each internal electrode portion 15 of the completed piezoelectric actuator 1 is collected. . The positional deviation data may be fed back to the design of the piezoelectric actuator 1. Thereby, even if it does not confirm the position of the internal electrode part 15 in a manufacturing process, the piezoelectric actuator 1 in which the position of the said internal electrode part 15 and each surface individual electrode 10 matched in the lamination direction can be obtained.

  FIG. 8 is a plan view of the main part of the piezoelectric actuator 25 according to the second embodiment of the present invention. This embodiment is different from the above embodiment in that the small hole 17 is formed so as to overlap the electrode terminal 26 in plan view. The position where the electrode terminal 26 is formed on the upper surface of the top layer 7 is the same as in the first embodiment. Each small hole 17 is formed at an end in the lateral direction of each internal electrode portion 15 (a position corresponding to the extension portion of the internal electrode portion 15 described above), and the electrode terminal 26 is connected to the true end of each small hole 17. Formed on top.

  In a state where the piezoelectric actuator 25 is completed, each small hole 17 is covered with each electrode terminal 26, and neither the internal electrode portion 15 nor the external common electrode 12 exists immediately below each electrode terminal 26. Thereby, between the electrode terminal 26 for electrically connecting each surface individual electrode 10 with wiring (the drive terminal electrode of a wiring member), and the extension part of the internal electrode part 15 required in order to provide the small hole 17 The stray capacitance can be reduced. Since the capacity between the electrode terminal 26 and the extension part of the internal electrode part 15 does not contribute to the change in the volume of the pressure chamber 13, it is possible to suppress wasteful power consumption by reducing this capacity. it can.

  FIG. 9 is a cross-sectional view of the piezoelectric actuator 28 according to the third embodiment of the present invention. The present embodiment is different from the first and second embodiments in that the piezoelectric actuator 28 is composed of four layers and the form of the active portion that deforms the pressure chamber 13 of the flow path unit 3 is different. The piezoelectric actuator 28 of the present embodiment includes a top layer 29 made of a piezoelectric material, a first intermediate layer 30, a second intermediate layer 31, a bottom layer 32, a surface individual electrode 33 formed on the top surface of the top layer 29, Formed between the first common electrode 34 (second electrode layer; GND electrode) formed between the top layer 29 and the first intermediate layer 30, and between the first intermediate layer 30 and the second intermediate layer 31. The internal individual electrode 35 (first electrode layer; internal electrode) and the second common electrode 36 (second electrode layer; GND electrode) formed between the second intermediate layer 31 and the bottom layer 32 I have.

  In a state where the piezoelectric actuator 1 is bonded to the flow path unit 3, each pressure chamber 13 of the flow path unit 3 is covered with the bottom layer 32, and the pressure chamber 13, each internal individual electrode 35, and each surface individual electrode 33 are connected to each other. Overlapping in the stacking direction. 10 is a plan view of the top layer 29, FIG. 11 is a plan view of the first intermediate layer 30, FIG. 12 is a plan view of the second intermediate layer 31, and FIG. 13 is a plan view of the bottom layer 32. is there.

  On the top surface of the top layer 29, eight rectangular surface individual electrodes 33 are arranged in a row. Except for the surface individual electrodes 33 arranged on both sides of FIG. 10, the surface individual electrodes 33 for every two rows are arranged in a staggered manner along the column direction. Furthermore, on the top surface of the top layer 29, electrode terminals 37 connected to the individual surface electrodes 33 are formed with the same width as the individual surface electrodes 33. A voltage is applied to each surface individual electrode 33 by joining a drive side electrode of a wiring member (not shown) provided on the upper surface of the top layer 29 to the electrode terminal 37.

  A first common electrode 34 is formed on the entire top surface of the first intermediate layer 30. The first common electrode 34 has an overlapping electrode portion 34a that overlaps the surface individual electrode 33 and the internal individual electrode 35 in the stacking direction. In addition, a transmissive portion 39 in which no electrode is formed is provided in a portion of the upper surface that does not overlap the individual surface electrode 33 in the stacking direction. The transmission part 39 includes four first slits 40 arranged in the row direction. A plurality of lands 41 for connecting the surface individual electrodes 33 and the internal individual electrodes 35 through through holes (not shown) are provided in the transmission portion 39 so as to overlap the electrode terminals 37 of the surface individual electrodes 33 in the stacking direction. ing.

  On the upper surface of the second intermediate layer 31, internal individual electrodes 35 are formed in rows at positions corresponding to the individual surface electrodes 33 in the stacking direction. The internal individual electrode 35 includes an electrode portion 35 a that overlaps the surface individual electrode 33 in the stacking direction, and an extension portion 35 b that protrudes from the surface individual electrode 33. The extension part 35b is extended toward the inner side of each of the two internal individual electrodes 35 from the adjacent ends in the row direction. Of the internal individual electrodes 35, the electrode portion 35 a is a portion that applies an electric field, and the extension portion 35 b is a portion that becomes a connection terminal connected to the electrode terminal 37. A small hole 44 through which light can be transmitted is formed in all the extension portions 35b.

  A second common electrode 36 is formed on the entire top surface of the bottom layer 32. The second common electrode 36 has an overlapping electrode portion 36a that overlaps the surface individual electrode 33 and the internal individual electrode 35 in the stacking direction. Further, a transmissive portion 42 on which no electrode is formed is provided in a portion of the upper surface that does not overlap the individual surface electrode 33 in the stacking direction. The transmission part 42 includes four second slits 43 arranged in the row direction. The first slit 40 of the first intermediate layer 30 and the second slit 43 of the bottom layer 32 do not overlap with the small holes 44 of the second intermediate layer 31 in the stacking direction.

  FIG. 14 is a plan view of the main part of the piezoelectric actuator 28. The second common electrode 36, the internal individual electrode 35, the first common electrode 34, and the surface individual electrode 33 overlap in the stacking direction. The internal individual electrode 35 extends in the lateral direction by an extension portion 35 b from the surface individual electrode 33. An electrode terminal 37 connected to the surface individual electrode 33 is located in a portion overlapping the extension portion 35b in the stacking direction. The small hole 44 formed in the extension portion 35b is formed at a position close to the surface individual electrode 33 in the stacking direction. The land 41 of the first intermediate layer 30 is formed at a position that overlaps the electrode terminal 37 in the stacking direction and avoids the small hole 44.

  Further, the piezoelectric actuator laminate 45 (hereinafter referred to as a laminate) according to the present invention in which the top layer 29, the first and second intermediate layers 30, 31 and the bottom layer 32 are laminated (hereinafter referred to as a laminate) In the state where the terminal 37 is not formed), the first and second slits 40 and 43 are positioned in the stacking direction at the positions of all the small holes 44, and when the stacked body 45 is viewed through Each small hole 44 is visible.

  Next, how the piezoelectric actuator 28 changes the volume of the pressure chamber 13 will be described. An active portion 46 corresponding to the pressure chamber 13 in the stacking direction is formed in the first and second intermediate layers 30 and 31 sandwiched between the internal individual electrode 35 and the first and second common electrodes 34 and 36. . The active layer 46 corresponding to the pressure chamber 13 in the stacking direction is also formed in the top layer 29 sandwiched between the individual surface electrode 33 and the first common electrode 34. In order to change the volume of the pressure chamber 13, a first potential is applied to the internal individual electrode 35 through the surface individual electrode 33, and a second potential (ground) is applied to the first and second common electrodes 34 and 36. Potential) is always applied. Thereby, the piezoelectric actuator 28 can change the volume of the pressure chamber 13 by applying a first potential as a drive signal to the internal individual electrode 35.

  Next, a method for manufacturing the piezoelectric actuator 28 will be described. The process is the same as in the first embodiment until the conductive material to be each electrode is printed on the green sheet by screen printing. The top layer 29, the first intermediate layer 30, the second intermediate layer 32, and the bottom layer 32 are stacked and sintered to obtain a stacked body 45 according to the present invention. Light is applied to the stacked body 45 from the stacking direction. The applied light passes through the piezoelectric body but does not pass through the electrodes.

  In the laminated body 45 of the present embodiment, a small hole 44 is formed in the extending portion 35b, and the first and second slits are located at positions overlapping the small holes 44 in the stacking direction of the first and second common electrodes 34 and 36. Since 40 and 43 are formed, the position of the small hole 44 can be confirmed by applying light to the laminated body 45 from one side. The position of each small hole 44 corresponds to the position of each internal individual electrode 35. Therefore, the position of each internal individual electrode 35 can be detected even after the laminate 45 is formed.

  Based on the position information of the internal individual electrodes 35, a plurality of surface individual electrodes 33 are formed on one outer surface of the multilayer body 45 by screen printing so as to align with the internal individual electrodes 35. Thereafter, electrode terminals 37 are formed on the upper surface of the top layer 29 by screen printing. Finally, a high voltage for polarization treatment is applied between the internal individual electrode 35 and the first and second common electrodes 34 and 36, and between the surface individual electrode 33 and the first common electrode 34. The ceramic sheet sandwiched between the two is polarized to give piezoelectric characteristics. Thereby, the piezoelectric actuator 28 is obtained.

  According to the method for manufacturing the piezoelectric actuator 28 using the laminate 45 of the present embodiment, the small holes 44 corresponding to the individual internal electrodes 35 are formed, and the small holes in the first and second common electrodes 34 and 36 are formed. Since the first and second slits 40 and 43 are formed at positions that do not block the light transmitted through 44, the position of the internal individual electrode 35 can be detected from the position of the small hole 44 when light is applied from one side. it can. And since each surface individual electrode 33 can be formed in the state which confirmed the position of each internal individual electrode 35, the piezoelectric actuator 28 in which the position of each internal individual electrode 35 and each surface individual electrode 33 in the lamination direction matched was obtained. be able to.

  Furthermore, according to the piezoelectric actuator 28 of the present embodiment, the position of each internal individual electrode 35 and each surface individual electrode 33 is confirmed by reconfirming the position of each internal individual electrode 35 after the piezoelectric actuator 28 is completed. Can be selected. Thereby, the quality of the piezoelectric actuator 128 can be improved. Further, the piezoelectric actuator 28 of the present embodiment is manufactured without checking the position of the internal individual electrode 35 in the manufacturing process, and the positional deviation data of each internal individual electrode 35 of the completed piezoelectric actuator 1 is collected. . The positional deviation data may be fed back to the design of the piezoelectric actuator 28. Accordingly, the piezoelectric actuator 28 in which the positions of the internal individual electrodes 35 and the individual surface electrodes 33 are aligned in the stacking direction can be obtained without checking the position of the internal individual electrodes 35 in the manufacturing process.

  Further, since the extension 35b is extended to the internal individual electrode 35 of the piezoelectric actuator, the extension 35b corresponding to the inactive portion and the second common electrode, and the electrode terminal 37 and the second common electrode are common. A region where stray capacitance may exist between the electrodes is formed. However, since the small hole is formed in the extension part 35b, the stray capacitance can be made as small as possible.

  FIG. 15 is a plan view of the main part of the piezoelectric actuator according to the fourth embodiment of the present invention. The present embodiment is different from the third embodiment in that the extension 52b of the internal individual electrode 52 is elongated and a small hole 53 is formed in the elongated portion. The configuration other than the internal individual electrodes is the same as that of the third embodiment.

  The extension 52 b of the internal individual electrode 52 extends further in the lateral direction than the extension of the third embodiment in the stacking direction, and protrudes outside the electrode terminal 37 of the top layer 29. The positions of the lands 41 are the same as those in the third embodiment, and the small holes 53 are formed at the ends protruding from the electrode terminals 37 in the stacking direction of the extension portions 52b. Therefore, when the piezoelectric actuator 51 is completed, each small hole 53 is not covered with each electrode terminal 37.

  16A and 16B are plan views of the main part of a piezoelectric actuator 55 according to the fifth embodiment of the present invention. This embodiment is different from the third embodiment in that the piezoelectric actuator 55 has a six-layer structure and two layers of internal individual electrodes 56 and 57 are provided in the stacking direction. FIG. 16A shows a plan view of only the two internal individual electrodes 56 and 57. Located on the flow path unit side in the stacking direction is the first internal individual electrode 56 shown on the upper side of the figure, and located on the opposite side of the first internal individual electrode 56 to the flow path unit. A second internal individual electrode 57 shown on the lower side of FIG. In addition, illustration and description of the configuration other than the first and second internal individual electrodes 56 and 57 are omitted.

Extending portions 56b and 57b are extended from both internal individual electrodes 56 and 57, respectively. A first small hole 58 is formed in the extension portion 56b of the first internal individual electrode 56, and a second small hole 59 is formed in the extension portion 57b of the second internal individual electrode. The first small hole 58 is formed with a width dimension of about one third of the width dimension of the first internal individual electrode. The second small hole 59 is formed to have a dimension that is one or more times larger than the first small hole 58.
FIG. 16B is a plan view showing a state in which the first and second internal individual electrodes 56 and 57 overlap in the stacking direction. Although not shown, the plurality of common electrodes formed in the piezoelectric actuator 55 are provided with slits formed so as not to block light passing through the first and second small holes 58 and 59. Since the first small holes 58 are located inside the second small holes 59 when viewed from the stacking direction, the light is transmitted through the first small holes 58 by applying light from one side of the stacked body, and the first internal individual electrodes 56. The position of the second internal individual electrode 57 can be detected. Thereby, the position in the lamination direction of the surface individual electrode formed in the top layer and the first and second internal individual electrodes 56 and 57 can be accurately matched.

  In addition, each said embodiment is an illustration and is not restrictive. The present invention can be applied to all piezoelectric actuators, laminated bodies for piezoelectric actuators, and manufacturing methods thereof. For example, the number of stacked piezoelectric actuators and the form of electrodes formed on each piezoelectric layer can be changed.

  The present invention can be applied to, for example, a piezoelectric actuator used in an inkjet head or the like.

1 is an exploded perspective view of an inkjet head in which a piezoelectric actuator 1 according to a first embodiment of the present invention is used. It is the fragmentary sectional view which abbreviate | omitted a part of the inkjet head cut | disconnected along the II line | wire of FIG. It is a top view of a top layer. It is a top view of an intermediate | middle layer. It is a top view of a bottom layer. It is a principal part top view of a piezoelectric actuator. It is sectional drawing cut | disconnected along the II-II line | wire of FIG. It is a principal part top view of the piezoelectric actuator which concerns on 2nd embodiment. It is sectional drawing which abbreviate | omitted a part of piezoelectric actuator which concerns on 3rd embodiment. It is a top view of a top layer. It is a top view of a 1st intermediate | middle layer. It is a top view of a 2nd intermediate | middle layer. It is a top view of a bottom layer. It is a principal part top view of a piezoelectric actuator. It is a principal part top view of the piezoelectric actuator which concerns on 4th embodiment. (A) is a top view of only two individual electrodes of the piezoelectric actuator according to the fifth embodiment, and (b) shows a state in which the first and second individual electrodes overlap in the stacking direction in the piezoelectric actuator. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piezoelectric actuator 2 Inkjet head 3 Flow path unit 10 Surface individual electrode 12 Common electrode 12a Overlapping electrode part 13 Pressure chamber 14 Electrode terminal 15 Internal electrode part 17 Small hole 19 Permeation | transmission part 20 Slit 23 Laminated body

Claims (7)

A plurality of stacked piezoelectric layers, a first electrode layer formed between two piezoelectric layers adjacent in the stacking direction of the plurality of piezoelectric layers, one piezoelectric layer of the two piezoelectric layers, and A second electrode layer formed between the piezoelectric layers other than the two piezoelectric layers,
One outer surface of the plurality of laminated piezoelectric layers is a laminate for a piezoelectric actuator for forming a surface on which a plurality of surface individual electrodes are provided,
Electrode terminals extend from each surface individual electrode,
The first electrode layer has a plurality of internal electrodes arranged at positions corresponding to the plurality of individual surface electrodes in plan view, and a small hole is formed in each of the plurality of internal electrodes,
The second electrode layer has an overlapping electrode portion formed so as to at least partially overlap each of the plurality of internal electrodes in a plan view, and a transmission portion that is a slit that covers the small hole,
The laminated body for piezoelectric actuators, wherein each electrode terminal overlaps with each small hole in a plan view. 2. The piezoelectric actuator laminate according to claim 1, wherein each internal electrode is formed with an extension portion that does not overlap with each surface individual electrode in plan view, and each of the small holes is formed in each extension portion. body. The multilayer body for a piezoelectric actuator according to claim 2, wherein the plurality of internal electrodes are formed in a row, and each extension portion is formed between two adjacent rows of internal electrodes. The plurality of internal electrodes of the first electrode layer are first constant potential electrodes to which a constant potential is applied, and the electrode portion of the second electrode layer has a potential different from the potential of the first constant potential electrode. Is a second constant potential electrode to which is applied,
By applying a first potential to each surface individual electrode, a first active portion is formed between each surface individual electrode and the first constant potential electrode, and a second potential is applied to each surface individual electrode. The laminated body for piezoelectric actuators according to any one of claims 1 to 3, wherein a second active portion is formed between each surface individual electrode and the second constant potential electrode . A method for manufacturing a piezoelectric actuator, wherein a plurality of individual surface electrodes are provided on the one outer surface of the piezoelectric actuator laminate according to any one of claims 1 to 4,
The position of each small hole is confirmed by applying light from the stacking direction to the piezoelectric actuator laminate, and the position of each internal electrode is detected from the position of each small hole. Based on the position information of each internal electrode A method of manufacturing a piezoelectric actuator, wherein a plurality of individual surface electrodes are formed on the one outer surface so as to be aligned with the internal electrodes. A plurality of stacked piezoelectric layers; a first electrode layer formed between two piezoelectric layers adjacent in the stacking direction of the plurality of piezoelectric layers; one piezoelectric layer of the two piezoelectric layers; A piezoelectric actuator comprising: a second electrode layer formed between the piezoelectric layers; and a plurality of individual electrodes provided on one outer surface of the plurality of stacked piezoelectric layers,
The first electrode layer has a plurality of internal electrodes arranged at positions corresponding to the plurality of individual electrodes in plan view, and a small hole is formed in each of the plurality of internal electrodes,
The second electrode layer has an overlapping electrode portion formed so as to at least partially overlap each of the plurality of internal electrodes in a plan view, and a transmission portion that is a slit that covers the small hole,
On one outer surface of the plurality of piezoelectric layers, a plurality of electrode terminals for connecting to the drive side terminal electrode of the wiring member are provided so as to extend from the plurality of individual electrodes, respectively.
Each of the electrode terminals overlaps with each of the small holes in plan view. The piezoelectric actuator is a piezoelectric actuator for an ink-jet head that is bonded to a flow path unit having a plurality of pressure chambers and selectively changes the volume of the plurality of pressure chambers, wherein each internal electrode is a flat surface. The piezoelectric actuator according to claim 6, wherein the piezoelectric actuator has an extension portion that does not overlap the individual electrodes as viewed, and the small holes are formed in the extension portion.

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