JP5522126B2 - Method for manufacturing piezoelectric actuator and method for manufacturing liquid transfer device - Google Patents

Description

  The present invention relates to a piezoelectric actuator having a piezoelectric layer and a method for manufacturing a liquid transfer device having such a piezoelectric actuator.

  In the ink jet head described in Patent Document 1, when a piezoelectric actuator for applying pressure to ink in a pressure chamber is manufactured, a diaphragm made of a stainless material or the like is provided on the upper surface of the flow path unit so as to cover the pressure chamber. The lower electrode serving as a diffusion preventing layer is formed on the upper surface of the diaphragm, and the piezoelectric layer is formed thereon by the aerosol deposition method (AD method). Furthermore, annealing is performed by heating the piezoelectric layer at a high temperature in order to impart piezoelectric characteristics to the piezoelectric layer formed by the AD method. At this time, constituent atoms of the diaphragm heated together with the piezoelectric layer diffuse, but the diffusion of the atoms stops at the lower electrode as the diffusion preventing layer, and the constituent atoms of the diaphragm diffuse to the piezoelectric layer. Is prevented. This suppresses deterioration of the piezoelectric characteristics of the piezoelectric layer due to diffusion of constituent atoms of the diaphragm into the piezoelectric layer.

JP 2006-54442 A

  Since the exposed electrode is exposed on the opposite side of the vibration layer of the piezoelectric layer, when the through hole is formed by etching, the exposed electrode is damaged by the etching solution if the through hole is formed after the exposed electrode is formed. There is a fear. In order to prevent this, an extra step such as masking the exposed electrode is required before the through hole is formed by etching.

  An object of the present invention is to provide a method for manufacturing a piezoelectric actuator in which the exposed electrode is not damaged by the etching solution and does not require the above-described mask processing, and a method for manufacturing a liquid transfer apparatus having such a piezoelectric actuator. Is to provide.

The piezoelectric actuator manufacturing method of the present invention includes a vibration layer forming step of forming a vibration layer made of a ceramic material on one surface of a base material made of metal or silicon, and a vibration layer on the side opposite to the base material. A piezoelectric layer forming step for forming a piezoelectric layer, and a step performed after the piezoelectric layer forming step, wherein a part of the base material is removed so that the vibration layer of the base material Comprises a through hole forming step for forming a through hole that can face the vibration layer from the opposite side, and an electrode forming step for forming an electrode in at least a portion of the piezoelectric layer facing the through hole. In the hole forming step, the through hole is formed by etching, and the electrode forming step includes an exposed electrode forming step of forming an exposed electrode exposed on the opposite side of the piezoelectric layer from the vibration layer. And this exposure Electrode forming step, the later than the through hole forming step, and forming the exposed electrode by arranging the electrode material on a surface thereof opposite to the vibration layer of the piezoelectric layer (claim 1).

According to this, a through-hole can be easily formed in a base material made of metal or silicon by etching. In addition, since the exposed electrode is exposed on the opposite side of the piezoelectric layer from the vibration layer, when the through hole is formed by etching, if the through hole is formed after the exposed electrode is formed, the exposed electrode is removed by the etching solution. There is a risk of damage. In order to prevent this, an extra step such as masking the exposed electrode is required before the through hole is formed by etching. However, in the present invention, since the exposed electrode is formed after the through-hole is formed, the exposed electrode is not damaged by the etching solution as described above, and the above-described mask processing or the like becomes unnecessary. The exposed electrode of the present invention may be formed on the opposite side of the piezoelectric layer of the present invention from the vibration layer of the present invention. If this condition is satisfied, the exposed electrode is covered with a member that is not a component of the present invention. In addition, it includes a mode that is not exposed.

  In the method for manufacturing a piezoelectric actuator of the present invention, it is preferable that the piezoelectric layer is formed by an aerosol deposition method in the piezoelectric layer forming step.

In the piezoelectric actuator manufacturing method of the present invention, it is preferable that in the vibration layer film forming step, the vibration plate is formed by an aerosol deposition method.

  According to this, the vibration layer having a dense structure can be formed at high speed by the AD method.

  Further, unlike a piezoelectric layer that needs to have piezoelectric characteristics, it is not necessary to anneal the vibration layer formed by the AD method, and the vibration layer formed by the AD method is solidified at room temperature. Therefore, it is not necessary to heat the vibration layer at a high temperature when forming the vibration layer.

The manufacturing method of the liquid transfer device of the present invention includes a vibration layer forming step of forming a vibration layer made of a ceramic material on one surface of a pressure chamber plate made of metal or silicon, and forming a pressure chamber, and the vibration A piezoelectric layer forming step of forming a piezoelectric layer on the opposite side of the pressure chamber plate, and a step performed after the piezoelectric layer forming step, wherein a part of the pressure chamber plate is removed Thus, a pressure chamber forming step for forming a pressure chamber capable of facing the vibration layer from the side opposite to the vibration plate of the base material, and an electrode is formed on at least a portion of the piezoelectric layer facing the pressure chamber. An electrode forming step, wherein in the through hole forming step, the through hole is formed by etching, and the electrode forming step is exposed to the opposite side of the piezoelectric layer from the vibrating layer. Form Includes a exposed electrode forming step, the exposed electrode forming step, later than the through-hole forming step, the exposed electrode is arranged an electrode material on a surface thereof opposite to the vibration layer of the piezoelectric layer characterized in that (claim 4).

  Hereinafter, preferred embodiments of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. As shown in FIG. 1, the printer 1 includes a carriage 2, an ink jet head 3 (liquid transport device), a transport roller 4, and the like. The carriage 2 reciprocates in the scanning direction (left and right direction in FIG. 1). The inkjet head 3 is attached to the lower surface of the carriage 2 and ejects ink from a plurality of nozzles 15 (see FIG. 2) formed on the lower surface while reciprocating in the scanning direction together with the carriage 2. The conveyance roller 4 conveys the recording paper P in the paper feeding direction (frontward direction in FIG. 1). In the printer 1, printing is performed on the recording paper P by ejecting ink from the inkjet head 3 that reciprocates in the scanning direction together with the carriage 2 onto the recording paper P that is transported in the paper feeding direction by the transport roller 4.

  Next, the inkjet head 3 will be described. FIG. 2 is a plan view of the inkjet head 3 of FIG. FIG. 3 is a partially enlarged view of FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 5 is a cross-sectional view taken along line VV in FIG. As shown in FIGS. 2 to 5, the inkjet head 3 includes a flow path unit 31 in which an ink flow path including the pressure chamber 10 is formed, and a piezoelectric actuator 32 for applying pressure to the ink in the pressure chamber 10. It has.

  The flow path unit 31 is configured by stacking four plates of a cavity plate 21 (pressure chamber plate, base material), a base plate 22, a manifold plate 23, and a nozzle plate 24. Of these four plates 21 to 24, the three plates 21 to 23 excluding the nozzle plate 24 are made of a metal material such as stainless steel, and the nozzle plate 24 is made of a synthetic resin such as polyimide. Or the nozzle plate 24 may be comprised with the metal material similarly to the other three plates 21-23.

  A plurality of pressure chambers 10 (through holes) are formed in the cavity plate 21. The plurality of pressure chambers 10 have a substantially oval planar shape whose longitudinal direction is the scanning direction (left-right direction in FIG. 2), and penetrates the cavity plate 21 in the thickness direction. The plurality of pressure chambers 10 are arranged in two rows in the paper feeding direction (up and down direction in FIG. 2). In the base plate 22, substantially circular through holes 12 and 13 are formed at positions overlapping with both ends in the longitudinal direction of the pressure chamber 10 in plan view.

  The manifold plate 23 extends in two rows in the paper feed direction along the rows of pressure chambers 10, and in the scanning direction so as to connect the portions extending in the paper feed direction at the lower end in FIG. 2. An extended manifold channel 11 is formed. The manifold channel 11 is arranged at the right side of the plurality of pressure chambers 10 arranged on the right side of FIG. 2 in a plan view and on the left side of FIG. It arrange | positions so that it may overlap with the substantially left half of the several pressure chamber 10. FIG. Ink is supplied to the manifold channel 11 from an ink supply port 9 formed at the lower end in FIG. The manifold plate 23 is formed with a substantially circular through hole 14 at a portion overlapping the through hole 13 in plan view. A nozzle 15 is formed in the nozzle plate 24 at a portion overlapping the through hole 14 in plan view.

  The manifold channel 11 communicates with the pressure chamber 10 through the through hole 12, and the pressure chamber 10 communicates with the nozzle 15 through the through holes 13 and 14. As described above, the flow path unit 31 is formed with a plurality of individual ink flow paths from the outlet of the manifold flow path 11 to the nozzle 15 via the pressure chamber 10.

  The piezoelectric actuator 32 includes a vibration layer 41, a piezoelectric layer (a layer containing a piezoelectric material) 42, a common electrode 43, and a plurality of individual electrodes 44. The vibration layer 41 is made of a ceramic material such as alumina or zirconia, and is disposed on the upper surface of the cavity plate 21 so as to cover the plurality of pressure chambers 10.

  The piezoelectric layer 42 is a layer that includes a piezoelectric material mainly composed of lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate, on the upper surface of the vibration layer 41 (on the side opposite to the cavity plate 21). It is continuously arranged across a plurality of pressure chambers 10. The piezoelectric layer 42 is previously polarized in the thickness direction.

  The common electrode 43 is made of platinum, palladium, gold, silver, or the like, and is disposed over almost the entire area between the vibration layer 41 and the piezoelectric layer 42. The common electrode 43 is connected to a driver IC (not shown) via a flexible wiring board (FPC) (not shown), and is always held at the ground potential by the driver IC.

  The plurality of individual electrodes 44 (exposed electrodes) are made of the same material as that of the common electrode 43 and are disposed on the upper surface of the piezoelectric layer 42 (on the side opposite to the vibration layer 41) corresponding to the plurality of pressure chambers 10. The upper surface of the layer 42 is exposed. The individual electrode 44 has a substantially elliptical planar shape that is slightly smaller than the pressure chamber 10, and is disposed in a portion facing the substantially central portion of the pressure chamber 10 in plan view. The individual electrode 44 has an end on the opposite side to the nozzle 15 in the longitudinal direction extending to a portion not facing the pressure chamber 10 in the scanning direction, and a tip of the individual electrode 44 connected to an FPC (not shown). It has become. A driving potential is selectively applied to the plurality of individual electrodes 44 by a driver IC (not shown) via the FPC.

  Here, a driving method of the piezoelectric actuator 32 will be described. In the piezoelectric actuator 32, the plurality of individual electrodes 32 are previously held at the ground potential. When the piezoelectric actuator 32 is driven, a driving potential is selectively applied to any one of the plurality of individual electrodes 44. Then, a potential difference is generated between the individual electrode 44 to which the drive potential of the piezoelectric layer 42 is applied and the common electrode 43 held at the ground potential, and the portion of the piezoelectric layer 42 sandwiched between these electrodes has a thickness direction. An electric field is generated.

  Since the direction of the electric field coincides with the polarization direction of the piezoelectric layer 42, the portion of the piezoelectric layer 42 facing the pressure chamber 10 contracts in a horizontal direction orthogonal to the direction of the electric field. Accordingly, the portions of the piezoelectric layer 42 and the vibration layer 41 facing the pressure chamber 10 are deformed so as to be convex toward the pressure chamber 10 as a whole. As a result, the volume of the pressure chamber 10 decreases, the pressure of the ink in the pressure chamber 10 increases (pressure is applied to the ink in the pressure chamber 10), and ink is ejected from the nozzle 15 communicating with the pressure chamber 10. The

  Next, a method for manufacturing the inkjet head 3 (piezoelectric actuator 32) will be described. FIG. 6 is a flowchart showing the manufacturing process of the inkjet head 3. FIG. 7 is a process diagram showing the state of the inkjet head 3 in each process of manufacture.

  When the inkjet head 3 (piezoelectric actuator 32) is manufactured, first, as shown in FIGS. 6 and 7A, the upper surface (one of the substrate) of the cavity plate 21 (base material) before the pressure chamber 10 is formed. The vibration layer 41 is formed on the surface) by an aerosol deposition method (AD method) in which an aerosol containing fine particles of a ceramic material is sprayed to form a film (step S101, hereinafter referred to simply as S101). Membrane process). Thus, by forming the vibration layer 41 by the AD method, the vibration layer 41 can have a dense structure and the thickness thereof can be reduced.

  Here, in order to sufficiently deform the vibration layer 41 when the piezoelectric actuator 32 is driven as described above, the greater the thickness of the vibration layer 41, the more the scanning direction and the paper feed direction (the surface direction of the cavity plate 21). It is necessary to increase the length of the pressure chamber 10 with respect to.

  Therefore, when the thin vibration layer 41 is formed by the AD method as in the present embodiment, the piezoelectric actuator 32 is driven even if the length of the pressure chamber 10 in the scanning direction and the paper feeding direction is small. Moreover, the vibration layer 41 is sufficiently deformed. Therefore, the pressure chamber 10 and the drive portion of the piezoelectric actuator 32 (portion facing the pressure chamber 10) can be highly integrated.

  Next, the common electrode 43 is formed on the upper surface of the vibration layer 41 as shown in FIGS. 6 and 7B by screen printing, sputtering, or the like (S102). Subsequently, as shown in FIGS. 6 and 7C, the upper surface (cavity plate) of the vibration layer 41 on which the common electrode 43 is formed by an AD method in which an aerosol containing fine particles of piezoelectric material is sprayed to form a film. The piezoelectric layer 42 is formed on the opposite side of the substrate 21 (S103, piezoelectric layer forming step).

  Next, by removing a part of the cavity plate 21, as shown in FIG. 6 and FIG. 7D, the cavity plate 21 is penetrated in the thickness direction of the cavity plate 21 from below (cavity plate). The pressure chamber 10 (through hole) that can face the vibration layer 41 (from the side opposite to the vibration layer 41 of 21) is formed (S104, through hole forming step, pressure chamber forming step). Here, since the cavity plate 21 is made of a metal material such as stainless steel, the pressure chamber 10 can be easily formed by etching.

  Next, as shown in FIGS. 6 and 7E, a plurality of individual electrodes 44 are formed on the upper surface of the piezoelectric layer 42 by screen printing, sputtering, or the like (S105, exposed electrode forming step).

  Here, contrary to the present embodiment, it is also possible to form the pressure chamber 10 in the cavity plate 21 by etching after forming a plurality of individual electrodes 44 on the upper surface of the piezoelectric layer 42. However, in this case, since the individual electrode 44 is exposed on the upper surface of the vibration layer 42, the etching solution adheres to the individual electrode 44 when the pressure chamber 10 is formed in the cavity plate 21 by etching. The individual electrode 44 may be damaged. In order to prevent this, an extra step such as masking the individual electrode 44 is required before the pressure chamber 10 is formed by etching.

  In contrast, in the present embodiment, the individual electrode 44 is formed after the pressure chamber 10 is formed (the exposed electrode forming step is performed after the through-hole forming step). The individual electrode 44 is not damaged, and it is not necessary to mask the individual electrode 44. Therefore, the manufacturing process is simplified correspondingly. The electrode forming the electrode in at least a portion facing the pressure chamber 10 of the piezoelectric layer 42 according to the present invention is a combination of the step of forming the common electrode and the step of forming the individual electrode 44 described above. This corresponds to the forming step.

  Next, the laminate of the cavity plate 21, the vibration layer 41, the common electrode 43, the piezoelectric layer 42, and the plurality of individual electrodes 44 is heated at a high temperature (for example, about 850 ° C.) (S106, heating step). As a result, annealing is performed at a high temperature in order to impart piezoelectric characteristics to the piezoelectric layer 42 formed by the AD method, and the common electrode 43 and the individual electrodes 44 are baked.

  At this time, the constituent atoms of the cavity plate 21 (for example, Cr atoms when the cavity plate 21 is made of stainless steel) are diffused into the vibration layer 41 and the piezoelectric layer 42 by the heating. When the constituent atoms of the cavity plate 21 diffuse into the portion of the piezoelectric layer 42 facing the pressure chamber 10, the piezoelectric characteristics in this portion of the piezoelectric layer 42 deteriorate, and as a result, when the piezoelectric actuator 32 is driven. The deformation amount of the piezoelectric layer 42 and the vibration plate 41 is reduced, and the ink ejection characteristics from the nozzles 15 are reduced.

  However, in this embodiment, since the pressure chamber 10 is formed in the cavity plate 21 by etching before heating, even if constituent atoms of the cavity plate 21 diffuse into the vibration layer 41 and the piezoelectric layer 42, Difficult to diffuse in the portion of the piezoelectric layer 42 facing the pressure chamber 10. Therefore, it is suppressed that the piezoelectric characteristic of the part which opposes the pressure chamber 10 of the piezoelectric layer 42 falls, and the deformation amount of the piezoelectric layer 42 and the vibration layer 41 when the piezoelectric actuator 32 is driven will fall. Can be suppressed.

  Furthermore, as described above, since the vibration layer 41 of the ceramic material is formed by the AD method, the vibration layer 41 has a dense structure, and the constituent atoms diffused from the cavity plate 21 are absorbed by the vibration layer 41. It is stopped and hardly diffuses to the piezoelectric layer 42. This further suppresses the deterioration of the piezoelectric characteristics of this portion of the piezoelectric layer 42.

  Here, contrary to the present embodiment, it is possible to form the individual electrode 44 on the upper surface of the piezoelectric layer 42 after the heating, but in this case, the annealing of the piezoelectric layer 42 is performed by the heating. In addition, only the common electrode 43 is fired, and in order to fire the individual electrode 44 formed thereafter, it is necessary to heat the individual electrode 44 separately from the above heating.

  On the other hand, in the present embodiment, the common electrode 43 and the plurality of individual electrodes 44 are formed before the heating (the electrode forming process is performed before the heating process). The annealing of the layer 42 and the firing of the common electrode 43 and the individual electrode 44 can be performed simultaneously.

  Thereafter, the cavity plate 21 and the previously prepared base plate 22, manifold plate 23, and nozzle plate 24 are joined to each other (S107). Thereby, the inkjet head 3 is completed. After the heating step (S106), it is necessary to perform a polarization step for polarizing the piezoelectric layer. For example, by holding the common electrode 43 at the ground potential and setting the individual electrode 44 to a potential higher than the drive potential, Polarization is applied in the thickness direction of the piezoelectric layer.

  According to the embodiment described above, when the piezoelectric layer 42 is formed by the AD method, annealing for heating the piezoelectric layer 42 at a high temperature is necessary in order to give the piezoelectric layer 42 piezoelectric characteristics. The constituent atoms of the cavity plate 21 heated together with the layer 42 diffuse into the vibration layer 41 and the piezoelectric layer 42.

  However, in the present embodiment, before heating the stacked body of the cavity plate 21, the vibration layer 41, the common electrode 43, the vibration layer 42, and the individual electrode 44, a part of the cavity plate 21 is removed to make the pressure chamber 10 Thus, even if the constituent atoms of the cavity plate 21 are diffused by the subsequent heating, the constituent atoms of the cavity plate 21 are difficult to diffuse into the portion of the piezoelectric layer 42 facing the pressure chamber 10. Thereby, it can suppress that the piezoelectric characteristic of this part of the piezoelectric layer 42 falls.

  Furthermore, in this embodiment, since the vibration layer 41 is formed by the AD method, the vibration layer 41 having a dense structure can be formed at a high speed. In addition, since the vibration layer 41 disposed between the cavity plate 21 and the piezoelectric layer 42 has a dense structure, the constituent atoms of the cavity plate 21 diffused during heating stop at the vibration layer 41, and the piezoelectric layer 41 is piezoelectric. Difficult to diffuse up to the layer 42. Therefore, it is possible to more effectively suppress the deterioration of the piezoelectric characteristics of the portion of the piezoelectric layer 42 facing the pressure chamber 10.

  Further, in order to sufficiently deform the vibration layer 41 when the piezoelectric actuator 32 is driven, it is necessary to increase the length of the pressure chamber 10 in the scanning direction and the paper feeding direction as the thickness of the vibration layer 41 increases. . However, in the present embodiment, since the vibration layer 41 is formed by the AD method, the vibration layer 41 can be thinned, thereby reducing the length of the pressure chamber 10 in the scanning direction and the paper feeding direction. However, the vibration layer 41 can be sufficiently deformed. Therefore, the drive portion of the pressure chamber 10 and the piezoelectric actuator 32 facing the pressure chamber 10 can be highly integrated.

  Further, since the cavity plate 21 is made of a metal material such as stainless steel, the pressure chamber 10 can be easily formed in the cavity plate 21 by etching.

  In addition, since the individual electrode 44 is formed on the upper surface of the piezoelectric layer 42 after the pressure chamber 10 is formed in the cavity plate 21 by etching, the etching solution adheres to the individual electrode 44 when the pressure chamber 10 is formed. Thus, the individual electrode 44 is not damaged. This eliminates the need for a process such as masking the individual electrode 44 before etching.

  In the present embodiment, after the individual electrode 44 is formed, the laminate of the cavity plate 21, the vibration layer 41, the common electrode 43, the piezoelectric layer 42, and the individual electrode 44 is heated to thereby anneal the piezoelectric layer 42. The firing of the individual electrode 44 and the common electrode 43 can be performed simultaneously.

  Next, modified examples in which various changes are made to the present embodiment will be described. However, components having the same configuration as in the present embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  In the present embodiment, the piezoelectric layer 42 is formed by the AD method. However, the piezoelectric layer 42 can be formed by another method. Specifically, for example, a vibrating layer in which the common electrode 43 is formed from a liquid slurry made by mixing a raw material powder made of a piezoelectric material and a sintering aid such as glass, an organic binder, and a plasticizer with a solvent. The piezoelectric layer 42 may be formed by coating on the upper surface of 41.

  In this case, after applying the slurry, the cavity plate 21, the vibration layer 41, the common electrode 43, the piezoelectric layer 42, and the individual electrode 44 are used for firing (solidification) of the piezoelectric layer 42 and annealing of the piezoelectric layer 42. The laminate is heated at a high temperature (for example, 850 ° C. or higher). For this reason, the constituent atoms of the cavity plate 21 diffuse when the piezoelectric layer 42 is baked. However, even in this case, since the piezoelectric layer 42 is heated after the pressure chamber 10 is formed in the cavity plate 21 as in the embodiment, the constituent atoms of the cavity plate 21 are changed to the pressure chamber of the piezoelectric layer 42. Difficult to diffuse in the part facing 10.

  In the present embodiment, the vibration layer 41 is formed by the AD method. However, the vibration layer 41 may be formed by another method. Specifically, the vibrating layer 41 formed at a low temperature that does not diffuse its constituent atoms from the cavity plate 21 such as a sol-gel method, a sputtering method, a CVD method (chemical vapor deposition method), or a hydrothermal synthesis method is solidified. It is also possible to form the vibration layer 41 by a method that can be used.

  In this embodiment, after the piezoelectric layer 42 is formed by the AD method, annealing is performed to heat the piezoelectric layer 42 at a high temperature. However, as described above, the piezoelectric layer 42 has a piezoelectric characteristic. This process is not for solidifying the piezoelectric layer 42. Then, the vibration layer 41 and the piezoelectric layer 42 formed by the AD method are solidified at room temperature. That is, even when the vibration layer 41 is formed by the AD method as in the above embodiment, the formed vibration layer 41 can be solidified at a normal temperature at which the constituent atoms do not diffuse from the base material 21.

  Here, after forming the vibration layer 41, in order to form the common electrode 43 and the like on the upper surface thereof, the vibration layer 41 needs to be solidified. For this solidification, the cavity plate 21, the vibration layer 41, Is heated at such a high temperature that the constituent atoms of the cavity plate 21 diffuse, the vibrating layer including a portion in which the constituent atoms of the cavity plate 21 face the pressure chamber 10 is heated. 41 spreads over the entire area. Therefore, even after the pressure chamber 10 is formed in the cavity plate 21 and then the piezoelectric layer 42 is heated for annealing, the pressure layer 10 of the vibration layer 41 is diffused to the portion facing the pressure chamber 10. The constituent atoms of the cavity plate 21 may diffuse from the vibration layer 41 to a portion of the piezoelectric layer 42 that faces the pressure chamber 10, and the piezoelectric characteristics of this portion of the piezoelectric layer 42 may be degraded.

  Therefore, it is preferable to form the vibration layer 41 using a method that can be solidified at a low temperature such that the constituent atoms of the cavity plate 21 do not diffuse as described above.

  Further, in the present embodiment, after the pressure chamber 10 is formed in the cavity plate 21, the individual electrode 44 is formed on the upper surface of the piezoelectric layer 42. However, after the individual electrode 44 is formed on the upper surface of the piezoelectric layer 42, The pressure chamber 10 may be formed in the cavity plate 21. In this case, in order to prevent the individual electrode 44 from being damaged by the etching solution, the individual electrode 44 may be masked before the pressure chamber 10 is formed in the cavity plate 21 by etching.

  In the present embodiment, after the individual electrode 44 is formed, the laminate of the cavity plate 21, the vibration layer 41, the common electrode 43, the piezoelectric layer 42, and the individual electrode 44 is heated to anneal the piezoelectric layer 42, Although the individual electrode 44 and the common electrode 43 are fired, the present invention is not limited to this. For example, after forming the pressure chamber 10 in the cavity plate 21 and before forming the individual electrodes 44, the laminate of the cavity plate 21, the vibration layer 41, the common electrode 43, and the piezoelectric layer 42 is heated to form the piezoelectric layer 42. Lamination and firing of the common electrode 43 are performed, and then the individual electrode 44 is formed on the upper surface of the piezoelectric layer 42. In order to fire the formed individual electrode 44, the individual electrode 44 is laminated separately from the above. The body may be heated.

  The cavity plate is not limited to a metal material such as stainless steel, and the cavity plate may be made of silicon. Even when silicon atoms diffuse into the piezoelectric layer 42, the piezoelectric characteristics of the piezoelectric layer 42 deteriorate. However, even in this case, the pressure chamber 10 is removed by removing a part of the cavity plate 21 before heating. Therefore, as in the embodiment, silicon atoms are unlikely to diffuse into the portion of the piezoelectric layer 42 facing the pressure chamber 10. Furthermore, even when the base material to be the cavity plate is made of silicon, the pressure chamber can be easily formed in the base material by etching.

  In the present embodiment, only one piezoelectric layer 42 is formed on the upper surface of the vibration layer 41. However, the present invention is not limited to this. In one modified example, as shown in FIG. 8, piezoelectric layers 71 and 72 are further disposed on the upper surface of the piezoelectric layer 42, and the common electrode 74 is disposed between the piezoelectric layer 71 and the piezoelectric layer 72 over almost the entire region. Is disposed, and an individual electrode 74 (exposed electrode) having the same shape as the individual electrode 44 is disposed on a portion of the upper surface (opposite side of the vibration layer 41) of the piezoelectric layer 72 facing the pressure chamber 10. (Modification 1). In this case, the combination of the piezoelectric layers 42, 71 and 72 corresponds to the piezoelectric layer according to the present invention. In this case, unlike the above-described embodiment, the individual electrode 44 does not correspond to the exposed electrode according to the present invention.

  When manufacturing such an ink jet head, as shown in FIGS. 7A to 7C, vibration is applied to the upper surface of the cavity plate 21 before the pressure chamber 10 is formed, as in the present embodiment. After forming the layer 41, the common electrode 43, and the piezoelectric layer 42, as shown in FIG. 9A, the individual electrode 44 is formed on the upper surface of the piezoelectric layer 42, and then, as shown in FIG. 9B. Then, the piezoelectric layer 71 is formed on the upper surface of the piezoelectric layer 42. Subsequently, as shown in FIG. 9C, the common electrode 73 is formed on the upper surface of the piezoelectric layer 71, and then, the piezoelectric layer 72 is formed on the upper surface of the piezoelectric layer 71 as shown in FIG. 9D. To do. The piezoelectric layers 71 and 72 are formed by the AD method as in the piezoelectric layer 42, and the common electrode 73 is formed by screen printing or sputtering as in the common electrode 43.

  Next, as in the present embodiment, as shown in FIG. 9E, the pressure chamber 10 is formed in the cavity plate 21 by etching (through-hole forming step, pressure chamber forming step), and then FIG. As shown in f), the individual electrodes 74 are formed on the upper surface of the piezoelectric layer 72 by screen printing, sputtering, or the like (exposed electrode forming step). After that, the laminate of the cavity plate 21, the vibration layer 41, the piezoelectric layers 41, 42, 71, 72, the common electrodes 43, 73 and the individual electrodes 44, 74 is heated to form the piezoelectric layers 42, 71, 72. Annealing and firing of the common electrodes 43 and 73 and the individual electrodes 44 and 74 are performed (heating process).

  In this case, the combination of the steps of forming the piezoelectric layers 42, 71, 72 corresponds to the piezoelectric layer forming step according to the present invention, and the common electrodes 43, 73 and the individual electrodes 44, 74 are provided. A combination of the forming steps corresponds to the electrode forming step according to the present invention.

  Even in this case, since the individual electrode 74 is formed after the pressure chamber 10 is formed in the cavity plate 21 by etching, the individual electrode 74 is not damaged by the etching solution. Furthermore, since the heating process is performed after the individual electrodes 74 are formed, the individual electrodes 74 are fired simultaneously with the annealing of the piezoelectric layers 42, 71, 72 and the firing of the common electrodes 43, 73 and the individual electrodes 44. It can be carried out.

  In the present embodiment, in the piezoelectric actuator 32, the common electrode 43 is disposed on the lower surface of the piezoelectric layer 42 and the plurality of individual electrodes 44 are disposed on the upper surface of the piezoelectric layer 42. The electrode may be disposed only on the upper surface or the lower surface of the piezoelectric layer 42.

  For example, in another modification, as shown in FIGS. 10 to 13, no electrode is formed on the lower surface of the piezoelectric layer 42, and the individual electrode 132 and the common electrode 134 are formed on the upper surface of the piezoelectric layer 42. (Modification 2).

  The plurality of individual electrodes 132 are formed on the top surfaces of the plurality of inner regions 140 that respectively face the plurality of pressure chambers 10. The pattern of each individual electrode 132 has a width from three longitudinal projections 145 extending in the longitudinal direction of the pressure chamber 10 (inner region 140) and two longitudinal projections 145 positioned on the outer side in the width direction of the pressure chamber 10. And a plurality of widthwise protrusions 146 extending outward in the direction. The three longitudinal protrusions 145 include the center of the substantially elliptical inner region 140, and are arranged on the upper surface of the first section 142 elongated in the longitudinal direction (left-right direction in FIG. 10) at equal intervals in the width direction. Yes. On the other hand, the plurality of widthwise protrusions 146 are located between two edges (the boundary between the inner region 140 and the outer region 141) of the pressure chamber 10 extending in parallel with the longitudinal direction and the outer edge of the first area 142. Further, they are arranged on the upper surface of the second area 143 facing the vicinity of the edge of the pressure chamber 10 at equal intervals in the longitudinal direction.

  The three longitudinal protrusions 145 are electrically connected to each other at one end portion (the right end portion in FIG. 10), and a contact portion 135 is drawn out from the conductive portion to the outer region 141. A plurality of contact portions 135 respectively corresponding to the plurality of individual electrodes 132 are arranged in the paper feed direction at both ends in the scanning direction. Further, an FPC (not shown) is joined to the plurality of contact parts 135, and the contact part 135 is electrically connected to a driver IC (not shown) via the wiring member. Since the three longitudinal protrusions 145 of the first section 142, the plurality of widthwise protrusions 146 of the second section 143, and the contact portion 135 are electrically connected to each other, the driver IC passes through the FPC and the contact portion 135. The driving voltage is applied to the three longitudinal protrusions 145 and the plurality of widthwise protrusions 146 simultaneously.

  The pattern of the common electrode 134 includes two longitudinal protrusions 147 each extending in the longitudinal direction of the pressure chamber 10 between the three longitudinal protrusions 145 of the individual electrodes 132 in each first area 142, and each second area 143. A plurality of width direction protrusions 148 extending in the width direction (short direction) of the pressure chamber 10 between the plurality of width direction protrusions 146 of the individual electrodes 132 are included. As shown in FIG. 10, in the first area 142, the three longitudinal protrusions 145 of the individual electrode 132 and the two longitudinal protrusions 147 of the common electrode 134 are alternately arranged at equal intervals. In the second region 143, the plurality of width direction protrusions 146 of the individual electrode 132 and the plurality of width direction protrusions 148 of the common electrode 134 are alternately arranged at equal intervals.

  Further, as shown in FIG. 10, the longitudinal protrusions 147 of the first section 142 corresponding to the two right and left rows of pressure chambers 10 are at the end opposite to the contact portion 135 (the left end in FIG. 10). The conductive portions 149 extending in the arrangement direction of the pressure chambers 10 (the vertical direction in FIG. 10) are all conducted. Further, the width direction protrusion 148 of the second section 143 is connected between two adjacent pressure chambers 10 by a conductive portion 150 extending in the longitudinal direction (left and right direction in FIG. 10), and the conductive portion 150 is connected to the conductive portion 149. It is connected to the. That is, the longitudinal protrusion 147 and the width protrusion 148 of the common electrode 134 are electrically connected to each other via the conductive portions 149 and 150. Further, the width direction protrusion 148 includes a first width direction protrusion 148a extending from the conductive portion 150 toward one side in the width direction of the pressure chamber 10 (upper side in FIG. 10) and the other side in the width direction (lower side in FIG. 10). ) Extending in the direction of), and the first width direction protrusion 148a and the second width direction protrusion 148b are common electrodes 134 for driving two adjacent pressure chambers 10. Are acting as each. That is, the first width direction protrusion 148a and the second width direction protrusion 148b that contribute to driving of different pressure chambers 10 are derived from one conductive portion 150, and the common electrode 134 is limited to a limited space. The pattern is arranged efficiently. Further, as shown in FIG. 10, two contact portions 136 are drawn out from the two left and right conductive portions 149 to both end portions in the scanning direction (same positions as the contact portions 135 of the individual electrodes 132 in the scanning direction). Similar to the contact part 135 of the individual electrode 132, the FPC is joined to the two contact parts 136. All the longitudinal projections 147 and the width projections 148 of the common electrode 134 are always held at the ground potential via the contact portions 136 and the wiring members.

  Thus, since the pattern of the individual electrode 132 and the pattern of the common electrode 134 are both formed on the upper surface of the piezoelectric layer 42, when a driving voltage is applied to a certain individual electrode 132, the piezoelectric layer 42 ( In particular, an electric field directed in a direction parallel to the surface (hereinafter sometimes referred to as a plane direction) is generated on the upper surface portion. As shown in FIG. 10, in the first section 142, between the longitudinal projections 145 of the individual electrodes 132 and the longitudinal projections 147 of the common electrode 134, as shown by the arrows, in the width direction of the pressure chamber 10. A first electric field E <b> 1 composed of a directed in-plane component is generated. On the other hand, in the second region 143, the longitudinal direction of the pressure chamber 10 orthogonal to the first electric field E1, as indicated by an arrow, between the widthwise protrusion 146 of the individual electrode 132 and the widthwise protrusion 148 of the common electrode 134 is shown. A second electric field E2 composed of an in-plane component facing the surface is generated.

  Further, the inner region 140 of the piezoelectric layer 42 is polarized in a direction parallel to the surface thereof by applying a voltage for polarization higher than the driving voltage to the individual electrode 132 in advance to cause a high electric field to act. Yes. The first section 142 is polarized in the same direction as the first electric field E1 (the width direction of the pressure chamber 10), and the second section 143 is polarized in the same direction as the second electric field E2 (the longitudinal direction of the pressure chamber 10). Has been. Therefore, the polarization direction of the piezoelectric layer 42 is the same as the direction of the electric field generated when a voltage is applied to the individual electrode 132.

  In the piezoelectric actuator of the second modification, when a driving voltage is selectively applied from the driver IC to the plurality of individual electrodes 132, the individual electrodes 132 and the common electrode 134 have different potentials. Then, as shown in FIG. 10, in the inner region 140 of the piezoelectric layer 131 on the lower side of the individual electrode 132 to which the driving voltage is applied, the first piezoelectric layer 42 in the first section 142 moves in the width direction of the pressure chamber 10. An electric field E1 is generated, and a second electric field E2 is generated in the piezoelectric layer 42 in the second section 143 in the longitudinal direction of the pressure chamber 10.

  Here, as described above, the piezoelectric layer 42 is polarized in the same direction as the first electric field E1 in the first section 142, and is polarized in the same direction as the second electric field E2 in the second section 143. Accordingly, as indicated by arrows in FIGS. 11 and 13, in the first section 142, the piezoelectric layer 42 extends in the width direction of the pressure chamber 10 that is the direction of the first electric field E <b> 1 and extends in the longitudinal direction of the pressure chamber 10. Shrink. On the other hand, in the second section 143, the piezoelectric layer 42 extends in the longitudinal direction of the pressure chamber 10 which is the direction of the second electric field E2, and contracts in the width direction of the pressure chamber 10. That is, as shown in FIG. 13, when viewed in the width direction of the pressure chamber 10, the piezoelectric layer 42 expands in the first section 142 and contracts in the second sections 143 on both sides thereof. At this time, the diaphragm 41 located below the piezoelectric layer 42 in the inner region 140 does not expand and contract in the surface direction, and resists the piezoelectric layer 42 in the inner region 140 from expanding and contracting in the surface direction. Furthermore, deformation in the thickness direction of the piezoelectric layer 42 in the outer region 141 surrounding the inner region 140 and the vibration plate 41 below the piezoelectric layer 42 are restricted. Therefore, as indicated by the broken lines in FIGS. 12 and 13, the piezoelectric layer 42 and the diaphragm 41 are greatly curved and deformed so as to protrude upward (on the side opposite to the pressure chamber 10). When the vibration plate 41 is curved in this manner, the volume of the pressure chamber 10 increases, a negative pressure wave is generated in the pressure chamber 10, and ink flows from the manifold channel 13 into the pressure chamber 10.

  Thereafter, the application of the drive voltage to the individual electrode 132 is stopped at the timing when the negative pressure wave generated in the pressure chamber 10 is reversed to positive. Then, the piezoelectric layer 42 and the vibration plate 41 return to the original horizontal shape, and the volume of the pressure chamber 10 decreases. At this time, the pressure wave accompanying the increase in the volume of the pressure chamber 10 and the restoration of the vibration plate 41 are obtained. Since the pressure wave generated along with this is combined, a large pressure is applied to the ink, and the ink is ejected from the nozzle 15.

  When manufacturing the ink jet head (piezoelectric actuator) of Modification 2, after forming the vibration layer 41 on the upper surface of the cavity plate 21, the piezoelectric layer 42 is immediately formed on the upper surface of the vibration layer 41. In the step of forming the individual electrode 44 in the embodiment, the individual electrode 132 and the common electrode 134 are formed. The other manufacturing steps are the same as those in the above-described embodiment, and the details are omitted here.

  And also in the modification 2, the effect similar to the above-mentioned embodiment can be acquired by manufacturing an inkjet head as mentioned above.

  In the present embodiment, the pressure chamber 10 is formed in the cavity plate 21 by etching. However, the pressure chamber 10 may be formed by other methods such as laser processing.

  In the above description, an example in which the present invention is applied to the manufacture of an inkjet head that discharges ink from nozzles in a pressure chamber and a piezoelectric actuator used therefor has been described, but the present invention is not limited thereto. For example, the present invention can be applied to the manufacture of a liquid discharge head that discharges liquid other than ink from a nozzle and a piezoelectric actuator used therefor, and includes a pressure chamber by applying pressure to the liquid in the pressure chamber. The present invention can also be applied to the manufacture of a liquid transfer device for transferring a liquid in a liquid transfer channel and a piezoelectric actuator used therefor.

  Furthermore, the present invention can also be applied to the manufacture of a piezoelectric actuator for driving a predetermined drive target. In this case, the driving target may be attached to the portion of the lower surface of the vibration layer 41 exposed in the through hole formed in the base material.

1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. It is a top view of the inkjet head of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is the IV-IV sectional view taken on the line of FIG. It is the VV sectional view taken on the line of FIG. It is a flowchart which shows the manufacture process of an inkjet head (piezoelectric actuator). It is a figure which shows the state of the inkjet head in each process of manufacture. FIG. 6 is a diagram corresponding to FIG. It is a figure which shows the state of the inkjet head in each process of manufacture of the inkjet head in the modification 1. It is a top view which shows a direction of the electric field which acts on a part of inkjet head in the modification 2, and a piezoelectric layer. It is a top view which shows a part of inkjet head in the modification 2, and the deformation | transformation direction of a piezoelectric layer. It is the sectional view on the AA line of FIG. It is the BB sectional drawing of FIG.

3 Inkjet head 10 Pressure chamber 21 Cavity plate 32 Piezoelectric actuator 41 Vibration layer 42 Piezoelectric layer 43 Common electrode 44 Individual electrode 71 Piezoelectric layer 72 Piezoelectric layer 73 Common electrode 74 Individual electrode

Claims (4)

A vibration layer forming step of forming a vibration layer made of a ceramic material on one surface of a base material made of metal or silicon;
A piezoelectric layer forming step of forming a piezoelectric layer on the vibration layer opposite to the base material;
A through-hole that is a step performed after the piezoelectric layer forming step, and can expose the vibration layer from a side opposite to the vibration layer of the substrate by removing a part of the substrate. A through-hole forming step for forming
An electrode forming step of forming an electrode on at least a portion of the piezoelectric layer facing the through hole,
In the through hole forming step, the through hole is formed by etching,
The electrode forming step includes an exposed electrode forming step of forming an exposed electrode exposed on the opposite side of the piezoelectric layer from the vibrating layer;
The exposed electrode forming step includes forming an exposed electrode by disposing an electrode material on a surface of the piezoelectric layer opposite to the vibrating layer after the through-hole forming step. Method.   2. The method of manufacturing a piezoelectric actuator according to claim 1, wherein in the piezoelectric layer forming step, the piezoelectric layer is formed by an aerosol deposition method.   3. The method for manufacturing a piezoelectric actuator according to claim 1, wherein in the vibration layer film forming step, the vibration plate is formed by an aerosol deposition method. A vibration layer forming step of forming a vibration layer made of a ceramic material on one surface of a pressure chamber plate made of metal or silicon and forming a pressure chamber;
A piezoelectric layer forming step of forming a piezoelectric layer on the vibration layer opposite to the pressure chamber plate;
A step that is performed after the piezoelectric layer forming step, and by removing a part of the pressure chamber plate, the pressure that allows the vibration layer to face the opposite side of the vibration plate of the base material A pressure chamber forming step for forming a chamber;
An electrode forming step of forming an electrode on at least a portion of the piezoelectric layer facing the pressure chamber,
In the through hole forming step, the through hole is formed by etching,
The electrode forming step includes an exposed electrode forming step of forming an exposed electrode exposed on the opposite side of the piezoelectric layer from the vibrating layer;
In this liquid transfer device, the exposed electrode forming step forms an exposed electrode by disposing an electrode material on the surface of the piezoelectric layer opposite to the vibrating layer after the through hole forming step. Production method.

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