JP2009178982A - Method for manufacturing piezoelectric actuator and method for manufacturing liquid transferring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture a piezoelectric actuator having a piezoelectric layer a part of which is curved and a liquid transferring device. <P>SOLUTION: In order to manufacture an inkjet head, a recessed part 51 having a curved surface 51a whose depth becomes larger and larger toward a center part is formed by half etching on an upper surface of a cavity plate 21 before a pressure chamber 10 is formed, and a protection layer 41 is deposited by an AD method on the upper surface of the cavity plate 21 on which the recessed part 51 has been formed. Next, a common electrode 43 is formed on an upper surface of the protection layer 41 and further the piezoelectric layer 42 is deposited by the AD method on the upper surface of the protection layer 41 on which the common electrode 43 has been formed. Then, the part of the cavity plate 21 where the recessed part 51 has been formed is removed by etching, so as to form the pressure chamber 10 piercing through the cavity plate 21. An individual electrode 44 is formed on an upper surface of the piezoelectric layer 42, and then heat treatment is performed to anneal the piezoelectric layer 42 and calcine the common electrode 43 and the individual electrode 44. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  In the ink jet head described in Patent Document 1, a piezoelectric element is disposed so as to cover an ink chamber (pressure chamber), and the piezoelectric element is curved toward a side opposite to the pressure chamber at a portion facing the pressure chamber. ing. In addition, the piezoelectric element having a curved portion facing the pressure chamber is polished by thin layer of the piezoelectric material or by injection molding using a mold having a curved surface similar to the above-described curve. I am making it.

JP 2005-512844 A

  Further, according to the polishing and injection molding of the piezoelectric material as described in Patent Document 1, the portion facing the pressure chamber is curved toward the pressure chamber, contrary to that described in Patent Document 1. It is also possible to produce a piezoelectric element. However, as described in Patent Document 1, when a piezoelectric element is manufactured by polishing a thin layer of piezoelectric material, it is difficult to accurately polish a curved portion, and it is manufactured by injection molding. In this case, there is a risk that the piezoelectric element may be warped when the piezoelectric element is taken out of the mold. That is, in any case, it is difficult to produce a piezoelectric element.

  An object of the present invention is to provide a method of manufacturing a piezoelectric actuator and a method of manufacturing a liquid transfer device that can easily manufacture a piezoelectric layer having a partially curved portion.

  The piezoelectric actuator manufacturing method of the present invention includes a concave portion that defines a curved surface that increases in depth toward the center or a convex portion that defines a curved surface that increases in height toward the center on one surface of a substrate. Forming a piezoelectric layer in which a portion facing the curved surface is curved to follow the curved surface on the one surface side of the base material on which the curved surface is formed A layer forming step and a step performed after the piezoelectric layer forming step, by removing a portion where the concave portion or the convex portion of the base material is formed, so that the side opposite to the piezoelectric layer of the base material is removed. A through-hole forming step of forming a through-hole that can face the piezoelectric layer, and an electrode forming step of forming an electrode on the surface of the piezoelectric layer.

  According to this, on one surface of the base material, a concave portion that defines a curved surface that increases in depth toward the center or a convex portion that defines a curved surface that increases in height toward the center is formed. By forming a piezoelectric layer in which a portion facing the curved surface is curved along the curved surface on one surface side of the substrate on which the substrate is formed, the piezoelectric layer curved so as to be convex or concave toward the through-hole side It can be formed easily.

  In addition, in the present invention, “curved along the curved surface” means “curved along the curved surface” and “another surface formed on one surface of the base material along the curved surface”. It is also included that a layer is formed and curved along the surface of this other layer.

  Further, in the method for manufacturing a piezoelectric actuator of the present invention, the piezoelectric layer in which a portion facing the curved surface is curved following the curved surface on the one surface of the base material before the piezoelectric layer forming step. It is preferable to further include a protective layer forming step of forming a protective layer for protecting the substrate, and in the piezoelectric layer forming step, the piezoelectric layer is formed on the surface of the protective layer opposite to the base material. 2).

  If the piezoelectric layer is exposed in the through hole, for example, the through hole is a pressure chamber constituting a liquid flow path, and the piezoelectric layer may be damaged when the piezoelectric layer and the liquid come into contact with each other. is there. However, in the present invention, since the protective layer is provided between the through hole and the piezoelectric layer, the piezoelectric layer is not exposed to the through hole, and such damage to the piezoelectric layer can be prevented.

  At this time, in the protective layer forming step, the protective layer is preferably formed by an aerosol deposition method.

  According to this, the protective layer having a dense structure can be formed at high speed by the aerosol deposition method (AD method).

  In the method for manufacturing a piezoelectric actuator of the present invention, the base material is made of metal or silicon, and further includes a heat treatment step for heat-treating the piezoelectric layer, and the heat treatment step is performed through a through hole. It is preferable to carry out after the forming step (claim 4).

  When the base material is made of metal or silicon and has a step of heat-treating the piezoelectric layer, the constituent molecules of the base material diffuse into the piezoelectric layer during the heat treatment, and the piezoelectric characteristics of the piezoelectric layer are lowered. There is a risk of it. However, in the present invention, since the through holes are formed in the base material before the heat treatment, the constituent molecules of the base material are difficult to diffuse into the portion of the piezoelectric layer facing the pressure chamber. Thereby, it can suppress that the piezoelectric characteristic in the part used for the drive of a piezoelectric layer falls.

  At this time, in the piezoelectric layer forming step, the piezoelectric layer is preferably formed by an aerosol deposition method.

  When the piezoelectric layer is formed by the aerosol deposition method (AD method), it is necessary to perform annealing for heating the piezoelectric layer at a high temperature to give the piezoelectric layer piezoelectric characteristics as a heat treatment step. However, even in such a case, in the present invention, since the through-hole forming step is performed before the heat treatment step, the constituent molecules of the base material face the through-holes of the piezoelectric layer by heating at the time of annealing. It is possible to suppress the diffusion to the part.

  In the method for manufacturing a piezoelectric actuator of the present invention, it is preferable that the heat treatment step is performed after the electrode forming step.

  When an electrode is formed by sputtering or the like, it is necessary to fire the formed electrode. However, in the present invention, by performing the heat treatment step after the electrode formation step, the electrodes can be fired simultaneously with the heat treatment of the piezoelectric layer.

  Moreover, in the manufacturing method of the piezoelectric actuator of this invention, it is preferable that the said recessed part or convex part formation process forms the said recessed part. (Claim 7). According to this, it can form easily by half etching etc. compared with the case where a convex part is formed.

  The manufacturing method of the liquid transfer device of the present invention has a concave portion that defines a curved surface whose depth increases toward the center, or a height that increases toward the center, on one surface of the pressure chamber plate in which the pressure chamber is formed. A concave portion or a convex portion forming step for forming a convex portion that defines the curved surface, and a portion facing the curved surface on the one surface side of the pressure chamber plate on which the curved surface is formed follows the curved surface. A piezoelectric layer forming step of forming a curved piezoelectric layer, and a step performed after the piezoelectric layer forming step, by removing the portion where the concave portion or the convex portion of the pressure chamber plate is formed, A pressure chamber forming step of forming a pressure chamber capable of facing the piezoelectric layer from a side opposite to the piezoelectric layer of the pressure chamber plate; and an electrode forming step of forming an electrode on the surface of the piezoelectric layer ( Claim 8).

  According to the present invention, on one surface of the base material, a concave portion that defines a curved surface that increases in depth toward the center, or a convex portion that defines a curved surface that increases in height toward the center, A piezoelectric layer that is curved so as to be convex or concave on the through-hole side by forming a piezoelectric layer in which the portion facing the curved surface is curved along the curved surface on one surface side of the substrate on which the curved surface is formed Layers can be easily formed.

  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 inkjet head 3, 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 row of pressure chambers 10 and extends in the scanning direction so as to connect the portions extending in the paper feed direction at the lower end in FIG. A manifold channel 11 is formed. In the portion extending in the paper feeding direction, the manifold channel 11 has a substantially right half of the plurality of pressure chambers 10 arranged on the right side in FIG. 2 and a plurality of pressures arranged on the left side in FIG. It arrange | positions so that it may overlap with the substantially left half of the chamber 10. FIG. Here, ink is supplied to the manifold channel 11 from an ink supply port 9 disposed at a position facing a substantially central portion of a portion extending in the scanning direction. 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 protective layer 41, a piezoelectric layer (a layer containing a piezoelectric material) 42, a common electrode 43, and a plurality of individual electrodes 44. The protective 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. Further, the protective layer 41 is curved so as to protrude toward the pressure chamber 10 at a portion facing the pressure chamber 10. Since the protective layer 41 is provided, the later-described common electrode 43 and the piezoelectric layer 42 are not exposed to the pressure chamber 10, and the ink in the pressure chamber 10 comes into contact with the common electrode 43 and the piezoelectric layer 42. There is nothing. Therefore, even an ink made of a material that reacts with the material constituting the common electrode 43 or the piezoelectric layer 42 can be used in the inkjet head 3.

  The piezoelectric layer 42 is a layer containing a piezoelectric material mainly composed of lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate, and spans the plurality of pressure chambers 10 on the upper surface of the protective layer 41. It is arranged continuously. As a result, the piezoelectric layer 42 is also curved so as to be convex toward the pressure chamber 10 at a portion facing the pressure chamber 10, similarly to the protective layer 41. The piezoelectric layer 42 is previously polarized in the thickness direction.

  The common electrode 43 is made of a conductive material such as platinum, palladium, gold, or silver, and is disposed over almost the entire area between the protective 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 are made of the same conductive material as the common electrode 43, and are arranged on the upper surface of the piezoelectric layer 42 so as to correspond to the plurality of pressure chambers 10. The individual electrode 44 has a substantially oval planar shape that is substantially the same size as the pressure chamber 10, and is disposed in a portion facing the substantially central portion of the pressure chamber 10 in plan view. Further, the end of the individual electrode 44 opposite to the nozzle 15 in the longitudinal direction extends to a portion that does not face the pressure chamber 10 in the scanning direction, and the tip thereof becomes a connection terminal 44a connected to an FPC (not shown). ing. A drive potential (for example, 20 V) is selectively applied to the plurality of individual electrodes 44 via an FPC by a driver IC (not shown).

  Here, a driving method of the piezoelectric actuator 32 will be described. FIG. 6 is a diagram illustrating a method for driving the piezoelectric actuator 32. In the piezoelectric actuator 32, as shown in FIG. 6A, the common electrode 43 is held at the ground potential and the plurality of individual electrodes 44 are both held at the ground potential. In this state, the portions of the piezoelectric layer 42 and the vibration layer 41 facing the pressure chamber 10 are curved so as to protrude toward the pressure chamber 10 as described above.

  When the piezoelectric actuator 32 is driven, a driving potential (for example, 20 V) is applied to any of the plurality of individual electrodes 44 as shown in FIG. 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, this portion of the piezoelectric layer 42 contracts in a horizontal direction orthogonal to the direction of the electric field. As a result, the portion facing the pressure chamber 10 of the piezoelectric layer 42 and the protective layer 41 that is curved so as to be convex toward the pressure chamber 10 side is lifted upward, and extends in the horizontal direction, or Thus, the curved state is smaller than before the driving potential is applied. As a result, the volume of the pressure chamber 10 increases, the pressure of the ink in the pressure chamber 10 decreases, and the ink flows from the manifold channel 11 into the pressure chamber 10.

  Then, after a predetermined time has elapsed, the potential of the individual electrode 44 to which the drive potential has been applied is returned to the ground potential. Then, the electric field in the portion sandwiched between the individual electrode 44 and the common electrode 43 of the piezoelectric layer 42 disappears, and the portions of the piezoelectric layer 42 and the protective layer 41 that oppose the pressure chamber 10 are removed as shown in FIG. Then, it returns to the curved state so as to be convex toward the pressure chamber 10. As a result, the volume of the pressure chamber 10 is reduced, the pressure of the ink in the pressure chamber 10 is increased (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. Discharged.

  Next, a method for manufacturing the inkjet head 3 (piezoelectric actuator 32) will be described. FIG. 7 is a flowchart showing the manufacturing process of the inkjet head 3. FIG. 8 is a diagram showing the state of the inkjet head 3 in each manufacturing process.

  In order to manufacture the inkjet head 3 (piezoelectric actuator 32), first, as shown in FIGS. 7 and 8A, the cavity plate 21 (base material) before the pressure chamber 10 is formed by half-etching is used. A curved surface corresponding to the curved shape of the vibration layer 41 and the piezoelectric layer 42 described above on a portion facing the pressure chamber 10 on the upper surface (one surface) and curved so that its depth increases toward the center. A recess 51 having 51a is formed (step S101, hereinafter referred to simply as S101). That is, by forming the recess 51, the curved surface 51 a is defined on the upper surface of the cavity plate 21. Here, since the cavity plate 21 is comprised with metal materials, such as stainless steel, the recessed part 51 which has such a curved surface 51a can be easily formed by half etching.

  Next, as shown in FIG. 7 and FIG. 8B, the upper surface of the cavity plate 21 in which the recesses 51 are formed by an aerosol deposition method (AD method) in which film formation is performed by spraying aerosol containing fine particles. A protective layer 41 is formed on the substrate (S102, protective layer forming step). Thereby, the protective layer 41 in which the portion facing the recess 51 is curved along the curved surface 51a is formed.

  Next, as shown in FIGS. 7 and 8 (c), the common electrode 43 is formed on the upper surface of the protective layer 41 by sputtering or the like (S103), and subsequently, as shown in FIGS. 7 and 8 (d). As described above, the piezoelectric layer 42 is formed on the upper surface (one surface side of the cavity plate 21) of the protective layer 41 on which the common electrode 43 is formed by the AD method (S104, piezoelectric layer forming step). As a result, the piezoelectric layer 43 whose portion facing the pressure chamber 10 is curved along the upper surface of the protective layer 41 that is curved similarly to the curved surface 51a (following the curved surface 51a) is formed.

  Next, as shown in FIGS. 7 and 8E, the portion of the cavity plate 21 where the recess 51 is formed is removed by etching, and the cavity plate 21 is penetrated through the cavity plate 21 in the thickness direction. Then, the pressure chamber 10 (through hole) that can face the protective layer 41 (the piezoelectric layer 42 having the protective layer 41 and the common electrode 43 formed on the lower surface) from below the cavity plate 21 is formed (S105, through hole formation). Process, pressure chamber forming process). 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. At this time, since the protective layer 41 is disposed between the cavity plate 21 and the piezoelectric layer 42, the common electrode 43 is not damaged by the etching solution.

  Next, as shown in FIGS. 7 and 8F, the individual electrodes 44 are formed on the upper surface of the piezoelectric layer 42 by sputtering or the like (S106). The combination of the step of forming the common electrode 43 in S103 described above and the step of forming the individual electrode 44 in S106 corresponds to the electrode forming step according to the present invention.

  Here, it is possible to form the individual electrode 44 on the upper surface of the piezoelectric layer 42 before forming the pressure chamber 10 in the cavity plate 21, but in this case, the pressure chamber 10 is formed in the subsequent cavity plate 21. In the process of forming, the etching solution may come into contact with the individual electrode 44 and 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 in the cavity plate 21 by etching.

  On the other hand, in the present embodiment, after the pressure chamber 10 is formed in the cavity plate 21 by etching, the individual electrode 44 is formed on the upper surface of the piezoelectric layer 42. Therefore, the individual electrode 44 is damaged by the etching solution. There is no need to mask the individual electrode 44.

  Next, the laminated body of the cavity plate 21, the protective layer 41, the common electrode 43, the piezoelectric layer 42, and the individual electrode 44 is heat-treated at a high temperature (for example, about 850 ° C.) (S107, heat treatment step). By this heat treatment, annealing for imparting piezoelectric characteristics to the piezoelectric layer 42 is performed, and the common electrode 43 and the individual electrodes 44 are fired.

  Here, when the heat treatment is performed, the constituent molecules diffuse from the cavity plate 21 made of a metal material such as stainless steel. When the constituent molecules of the cavity plate 21 diffuse into the portion of the piezoelectric layer 42 facing the pressure chamber 10, the piezoelectric characteristics of this portion of the piezoelectric layer 42 deteriorate, and the piezoelectric layer when the piezoelectric actuator 32 is driven. The amount of deformation of 42 is reduced. As a result, the ink ejection characteristics from the nozzles 15 are degraded.

  However, in the present embodiment, the pressure chamber 10 is formed in the cavity plate 21 before the heat treatment is performed (because the heat treatment process is performed after the through hole forming process), the cavity plate The constituent molecules 21 hardly 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.

  In contrast to the present embodiment, after the pressure chamber 10 is formed in the cavity plate 21, the above heat treatment is performed before the individual electrode 44 is formed, and then the individual electrode 44 is formed on the upper surface of the piezoelectric layer 42. However, in this case, only the annealing of the piezoelectric layer 42 and the firing of the common electrode 43 are performed by the above heat treatment, so that the individual electrode 44 formed thereafter is fired. A heat treatment different from that described above is required.

  On the other hand, in the present embodiment, after the individual electrodes 44 are formed, the heat treatment is performed (the heat treatment step is performed after the electrode formation step). This annealing and the firing of the common electrode 43 and the individual electrode 44 can be performed simultaneously, and the manufacturing process of the inkjet head 3 can be simplified.

  Thereafter, the cavity plate 21 and the other three plates 22 to 24 constituting the flow path unit 31 are joined (S108), and the inkjet head 3 is completed.

  According to the embodiment described above, the concave portion 51 having the curved surface 51a that becomes deeper toward the center is formed on the upper surface of the cavity plate 21 before the pressure chamber 10 is formed, and the concave portion 51 is formed. A portion of the cavity plate 21 facing the recess 51 is formed on the upper surface of the cavity plate 21 so as to follow the curved surface 51a, and then the protective layer 41 and the piezoelectric layer 42 are formed. Thereafter, the portion of the cavity plate 21 where the recess is formed is removed. By forming the pressure chamber 10, it is possible to easily form the protective layer 41 and the piezoelectric layer 42 that are curved so as to protrude toward the through hole 10. Further, the concave portion 51 having the curved surface 51a whose depth becomes deeper at the center can be easily formed in the cavity plate 21 by half etching or the like.

  Further, since the protective layer 41 is disposed between the cavity plate 21 in which the pressure chamber 10 is formed and the piezoelectric layer 42 in which the common electrode 43 is formed on the lower surface, the piezoelectric layer 42 and the common electrode 43 are connected to the pressure chamber. 10 and the piezoelectric layer 42 and the common electrode 43 are not damaged by the ink in the pressure chamber 10, the etching solution for forming the pressure chamber 10 in the cavity plate 21, or the like.

  Further, after the pressure chamber 10 is formed in the cavity plate 21, the heat treatment for annealing the piezoelectric layer 42 and firing the common electrode 43 and the individual electrode 44 is performed. The constituent molecules are unlikely 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.

  Further, the protective layer 41 having a dense structure can be formed at a high speed by the AD method. Since the protective layer 41 has a dense structure, the diffusion of the constituent molecules of the cavity plate 21 during the heat treatment described above stops at the protective layer 41 and is difficult to diffuse into the piezoelectric layer 42. Therefore, it can suppress more effectively that the piezoelectric characteristic of the part which opposes the pressure chamber 10 of the piezoelectric layer 42 falls.

  Further, since the heat treatment is performed after the individual electrode 44 is formed, the annealing of the piezoelectric layer 42 and the firing of the common electrode 43 and the individual electrode 44 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 one modification, as shown in FIG. 9, the vibration layer 41 (see FIG. 5) is not provided, and the common electrode 43 (the piezoelectric layer 42 having the common electrode 43 formed on the lower surface) is exposed in the pressure chamber 10. (Modification 1).

  In this case, in order to manufacture an ink jet head (piezoelectric actuator), as shown in FIG. 10A, after forming a recess 51 on the upper surface of the cavity plate 21, as shown in FIG. The common electrode 43 is formed directly on the upper surface of the cavity plate 21 in which the recess 51 is formed. Thereafter, as shown in FIGS. 10C to 10E, the piezoelectric layer 42, the pressure chamber 10, and the individual electrode 44 are formed as described in the embodiment, and the cavity plate is further formed. 21, the laminated body of the common electrode 43, the piezoelectric layer 42, and the individual electrode 44 is heat-treated to anneal the piezoelectric layer 42 and to fire the common electrode 43 and the individual electrode 44.

  However, in this case, since the common electrode 43 is exposed in the pressure chamber 10, when the pressure chamber 10 is formed in the cavity plate 21 by etching as shown in FIG. In order not to remove the portion of the common electrode 43 facing the pressure chamber 10, it is necessary to adjust the etching time and the like.

  In another modification, as shown in FIG. 11, piezoelectric layers 71 and 72 are further arranged on the upper surface of the piezoelectric layer 42, and between the piezoelectric layer 71 and the piezoelectric layer 72, A common electrode 73 similar to the common electrode 43 is disposed almost all over, and an individual electrode 74 similar to the individual electrode 44 is disposed on the upper surface of the piezoelectric layer 72 at a portion facing the pressure chamber 10 ( Modification 2).

  In this case, when the inkjet head is manufactured, as in the present embodiment, as shown in FIGS. 8A to 8D, the protective layer 41, the common electrode 42, and the After the piezoelectric layer 42 is formed, the individual electrode 44, the piezoelectric layer 71, the common electrode 73, and the piezoelectric layer 72 are sequentially formed on the upper surface thereof as shown in FIGS. The piezoelectric layers 71 and 72 are formed by the AD method similarly to the piezoelectric layer 42, and the common electrode 73 is formed by the sputtering method or the like similarly to the common electrode 43.

  Next, as shown in FIG. 12 (e), the pressure chamber 10 is formed in the cavity plate 21 by etching. Next, as shown in FIG. 12 (f), the upper surface of the piezoelectric layer 72 is individually formed by sputtering or the like. An electrode 74 is formed. And then, by heating the laminated body of the cavity plate 21, the protective layer 41, the piezoelectric layers 42, 71, 72, the common electrodes 43, 73, and the individual electrodes 44, 74 at a high temperature (for example, about 850 ° C.), The piezoelectric layers 42, 71, 72 are annealed, and the common electrodes 43, 73 and the individual electrodes 44, 74 are fired.

  Even in this case, since the heat treatment is performed after the common electrodes 43 and 73 and the individual electrodes 44 and 74 are all formed (the heat treatment process is performed after the electrode formation process), the piezoelectric layers 42, 71, and 72 are performed. And annealing of the common electrodes 43 and 73 and the individual electrodes 44 and 74 can be performed simultaneously. In this case, the steps of forming the piezoelectric layers 42, 71, 72 correspond to the piezoelectric layer forming step according to the present invention, respectively, and the steps of forming the common electrodes 43, 73 and the individual electrodes 44, 74 are included. These correspond to the electrode forming step according to the present invention.

  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, in addition to the AD method, the piezoelectric layer 42 can be formed by, for example, a sol-gel method, a sputtering method, a CVD method (chemical vapor deposition method), or a hydrothermal synthesis method. Further, 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 is applied to the upper surface of the vibration layer 41 on which the common electrode 43 is formed. The piezoelectric layer 42 may be formed by coating.

  In the present embodiment, the vibration layer 41 is formed by the AD method. However, the protective layer 41 can be formed by another method. Specifically, the protective layer 41 can be formed by a method such as a sol-gel method, a sputtering method, a CVD method (chemical vapor deposition method), or a hydrothermal synthesis method.

  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 etchant from adhering to the individual electrode 44 and damaging the individual electrode 44, a mask is applied to the individual electrode 44 before the pressure chamber 10 is formed in the cavity plate 21 by etching. do it.

  In this embodiment, after the individual electrode 44 is formed, the heat treatment is performed for annealing the piezoelectric layer 42 and firing the individual electrode 44 and the common electrode 43. However, 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, heat treatment for annealing the piezoelectric layer 42 and firing the common electrode 43 is performed, and then the upper surface of the piezoelectric layer 42 is formed. In order to form the individual electrode 44 and to fire the formed individual electrode 44, heat treatment may be performed separately from the above.

  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 molecules are diffused into the piezoelectric layer 42, the piezoelectric characteristics of the piezoelectric layer 42 are deteriorated. Even in this case, the pressure chamber 10 is formed in the cavity plate 21 before the heat treatment. Similar to the embodiment, silicon molecules hardly diffuse into the portion of the piezoelectric layer 42 facing the pressure chamber 10. Further, even when the base material to be the cavity plate is made of silicon, a concave portion having a curved surface whose depth becomes deeper toward the center by half etching can be easily formed, and the pressure chamber is formed in the base material by etching. Can be easily formed.

  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.

  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, 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, but the present invention is not limited thereto. For example, the present invention can also be applied to the manufacture of a liquid discharge head that discharges liquid other than ink from a nozzle and a piezoelectric actuator used therein, and includes a pressure chamber by applying pressure to the liquid in the pressure chamber. It is also possible to apply the present invention to the manufacture of a liquid transfer device for transferring the liquid in the liquid transfer channel and the 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 drive target may be attached to a portion of the lower surface of the piezoelectric layer or the protective layer that is exposed in the through hole formed in the base material.

  In the embodiment and the modification of the present invention described above, the curved surface 51a curved so that the depth thereof becomes deeper toward the center in the portion facing the portion to be the pressure chamber 10 on the upper surface of the cavity plate 21. A recess 51 having a shape is formed so that the vibration layer 41 and the piezoelectric layer 42 have a curved shape that follows the curved surface 51a. However, instead of the recess 51, a portion that faces the portion that becomes the pressure chamber 10 In addition, a convex portion that defines a curved surface that increases in height toward the center is formed, and the vibration layer 41 and the piezoelectric layer 42 have a curved shape that follows the curved surface (a curved surface that is convex on the side opposite to the pressure chamber 10). Shape).

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 figure which shows the drive method of an inkjet head. It is a flowchart which shows the manufacturing process of an inkjet head. 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. FIG. 8 is a diagram corresponding to FIG. 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 2.

Explanation of symbols

3 Inkjet head 10 Pressure chamber 21 Cavity plate 32 Piezoelectric actuator 41 Protective layer 42 Piezoelectric layer 51 Recessed portion 51a Curved surface 71 Piezoelectric layer 72 Piezoelectric layer 73 Common electrode 74 Individual electrode

Claims (8)

A concave portion or convex portion forming step for forming a concave portion defining a curved surface whose depth increases toward the center or a convex portion defining a curved surface whose height increases toward the center on one surface of the substrate; ,
A piezoelectric layer forming step of forming, on the one surface side of the base material on which the curved surface is formed, a piezoelectric layer in which a portion facing the curved surface is curved along the curved surface;
It is a step performed after the piezoelectric layer forming step, and the piezoelectric layer is removed from the opposite side of the base material from the side opposite to the piezoelectric layer by removing the concave portion or the convex portion of the base material. A through-hole forming step for forming a through-hole that can face,
A method for manufacturing a piezoelectric actuator comprising: an electrode forming step of forming an electrode on the surface of the piezoelectric layer. Before the piezoelectric layer forming step, a protective layer is formed on the one surface of the base material to form a protective layer for protecting the piezoelectric layer in which a portion facing the curved surface is curved following the curved surface A further process,
The method for manufacturing a piezoelectric actuator according to claim 1, wherein in the piezoelectric layer forming step, the piezoelectric layer is formed on a surface of the protective layer opposite to the base material.   3. The method for manufacturing a piezoelectric actuator according to claim 2, wherein in the protective layer forming step, the protective layer is formed by an aerosol deposition method. The base material is made of metal or silicon,
A heat treatment step of heat-treating the piezoelectric layer;
The method for manufacturing a piezoelectric actuator according to claim 1, wherein the heat treatment step is performed after the through-hole forming step.   5. The method for manufacturing a piezoelectric actuator according to claim 4, wherein in the piezoelectric layer forming step, the piezoelectric layer is formed by an aerosol deposition method.   6. The method for manufacturing a piezoelectric actuator according to claim 4, wherein the heat treatment step is performed after the electrode forming step.   The method for manufacturing a piezoelectric actuator according to claim 1, wherein the recess or protrusion forming step forms the recess. On one surface of the pressure chamber plate in which the pressure chamber is formed, a concave portion that defines a curved surface that increases in depth toward the center or a convex portion that defines a curved surface that increases in height toward the center is formed. A recess or protrusion forming step;
A piezoelectric layer forming step of forming, on the one surface side of the pressure chamber plate on which the curved surface is formed, a piezoelectric layer in which a portion facing the curved surface is curved along the curved surface;
A step performed after the piezoelectric layer forming step, wherein the piezoelectric chamber is removed from the side of the pressure chamber plate opposite to the piezoelectric layer by removing the concave portion or the convex portion of the pressure chamber plate. A pressure chamber forming step for forming a pressure chamber capable of facing the layer;
An electrode forming step of forming an electrode on the surface of the piezoelectric layer. A method for manufacturing a liquid transfer device.

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