JP5204380B2 - Piezoelectric element, method for manufacturing the same, and liquid ejection device - Google Patents

Description

  The present invention relates to a piezoelectric element, a manufacturing method thereof, and a liquid ejecting apparatus, and more particularly, a piezoelectric element having a piezoelectric film formed on a diaphragm, a manufacturing method of the piezoelectric element, and a liquid such as an ink jet recording apparatus using the piezoelectric element. The present invention relates to an ejection device.

  In recent years, a device that ejects liquid by vibration of a vibration plate such as an ink jet recording device or a micro pump can obtain a large displacement at a relatively low voltage, and thus a piezoelectric vibrator using a flexural vibration mode such as a monomorph is used. There are more and more cases to do.

  Conventionally, a technique for forming a piezoelectric film thinner than bulk adhesion by forming a piezoelectric film by a thin film technique and directly forming a film without using an adhesive has been proposed (Patent Documents 1 and 2).

  In the invention described in Patent Document 1, a PZT octylate mixture is spin-coated on a vibration plate attached to a head base having a large number of individual ink paths to form a PZT, and then positioned on the individual ink paths. Etch the PZT film in a pattern that leaves a PZT film on each part of the diaphragm, or screen-print a PZT octylate mixture on each part of the diaphragm located on the individual ink path to form PZT Thereafter, the PZT film is fired, and the PZT film is further polarized to form a PZT element on the diaphragm.

The invention described in Patent Document 2 includes a diaphragm that forms one wall surface of a cavity and has a lower electrode on at least an upper surface, a piezoelectric layer formed on the surface of the diaphragm by a thin film deposition method, and the In an actuator having a piezoelectric vibrator comprising a piezoelectric active part consisting of an upper electrode formed on the surface of a piezoelectric layer, an extension allowing the piezoelectric distortion of the piezoelectric active part at the center of the piezoelectric active part The part is formed.
Japanese Patent Laid-Open No. 5-286131 JP 11-129468 A

However, as in the invention described in Patent Document 1, when a piezoelectric film is directly formed on the diaphragm without using an adhesive,
(1) Piezoelectric film peels off or cracks are generated due to stress from the substrate (2) The piezoelectric constant d31 is worse than the bulk alone due to restraint from the substrate and the lateral direction (film itself) (3) High When the displacement is increased by the voltage, there are problems such as the film being cracked or peeled off.

  On the other hand, in order to solve the above-described problem, the invention described in Patent Document 2 forms an extension portion that allows piezoelectric distortion of the piezoelectric active portion at the center portion of the piezoelectric active portion, thereby destroying the piezoelectric layer. However, since the piezoelectric layer and the upper electrode are not formed in this extension, and a space for allowing piezoelectric distortion is formed, the space between the upper electrode and the lower electrode is formed by this space. There is a problem that discharge occurs. Further, since the upper electrode is not formed in the extending portion, there is a problem that the structure of the upper electrode is complicated.

  The present invention has been made in view of such circumstances, and can relieve stress after film formation and stress generated in the piezoelectric film itself when the diaphragm is displaced, thereby increasing the displacement of the diaphragm. Piezoelectric element that can prevent cracking and peeling of the piezoelectric film, and that does not discharge between the upper electrode and the lower electrode and does not complicate the structure of the upper electrode. It is an object to provide a method and a liquid ejection device.

In order to achieve the above object, according to the first aspect of the present invention, a lower electrode, a piezoelectric film, and an upper electrode are sequentially laminated on a vibration plate, and the lower electrode and the upper electrode are used for the piezoelectric film. In the piezoelectric element to which an electric field is applied, the piezoelectric film is formed by a film forming method in which a film is formed directly on the lower electrode, and the piezoelectric film has a plurality of grooves for one piezoelectric element , In addition, an insulator is provided in the groove, the lower electrode is formed over the diaphragm, and the upper electrode is formed on the piezoelectric film and the insulator, one for each piezoelectric element. It is characterized by being formed.

  Since the piezoelectric film is separated into a plurality of grooves filled with the insulator, stress generated in the piezoelectric film itself when the diaphragm is displaced can be relieved, thereby increasing the displacement of the diaphragm. In addition, the piezoelectric film can be prevented from cracking and peeling. Further, since the groove is filled with an insulator, this portion does not discharge between the upper electrode and the lower electrode. Furthermore, since the upper surface of the piezoelectric film in which the groove is filled with an insulator is flat, a normal upper electrode can be applied.

  According to a second aspect of the present invention, in the piezoelectric element according to the first aspect, the insulator has a lower Young's modulus than the piezoelectric film.

  According to a third aspect of the present invention, in the piezoelectric element according to the second aspect, the insulator has a Young's modulus lower than 50 GPa. That is, since the Young's modulus of the current piezoelectric film is 50 GPa or more, the insulator having a Young's modulus lower than this is used.

  According to a fourth aspect of the present invention, in the piezoelectric element according to any one of the first to third aspects, the insulator is made of a polymer material. The polymer material has a Young's modulus of several GPa, which is almost an order of magnitude lower than the Young's modulus of the piezoelectric film, and has an insulating property, and is suitable as the insulator.

  According to a fifth aspect of the present invention, in the piezoelectric element according to the fourth aspect, the polymer material is a synthetic resin or silicone rubber.

  According to a sixth aspect of the present invention, in the piezoelectric element according to the fifth aspect, the synthetic resin is a photocurable resin, a thermoplastic resin, or a thermosetting resin.

In the piezoelectric element according to any one of claims 1 to 6 as shown in claim 7, wherein the groove is the same depth as the thickness of the piezoelectric film, or those having a depth less than the thickness of the piezoelectric film It is characterized by being. In other words, in the present invention, the separation by the groove portion of the piezoelectric film includes not only the case where the piezoelectric film is completely separated but also the case where a part is connected.

As shown in claim 8 , in the piezoelectric element according to any one of claims 1 to 6 , the depth of the groove is 20% to 100% of the thickness of the piezoelectric film, preferably 50% to 100%, More preferably, it is 70 to 100%.

In the piezoelectric element according to any one of claims 1 to 8 as shown in claim 9, the shape of each piezoelectric film is divided by the groove portion, striped, rectangular, square, rhombic, and any honeycombed It is characterized by being.

According to a tenth aspect of the present invention, in the piezoelectric element according to any one of the first to eighth aspects, each piezoelectric film separated into a plurality by the groove has a side length of 100 μm or less.

Characterized in that the piezoelectric element according to any one of claims 1 to 10 as shown in claim 11, wherein the groove portion, a dry etching method, wet etching method, and those formed by either nanoimprinting It is said. In the dry etching method and the wet etching method, the groove is formed after the piezoelectric film is formed. In the nanoimprint method, the groove is formed by pressing a mold before the piezoelectric film is cured, and then cured.

In the piezoelectric element according to any one of claims 1 to 10 as shown in claim 12, piezoelectric film, piezoelectric film formed directly separated into a plurality using a mask corresponding to the groove having the groove It is characterized by being made. As a result, a groove is formed simultaneously with the formation of the piezoelectric film.

The piezoelectric element manufacturing method according to claim 13 includes a first step of forming a lower electrode over the diaphragm and a second step of forming a piezoelectric film by a film forming method of forming a film directly on the lower electrode. A step of separating the piezoelectric film into a plurality of grooves , a third step of forming a plurality of grooves for one piezoelectric element, a fourth step of filling the groove with an insulator, A fifth step of forming an upper electrode on the piezoelectric film separated into a plurality by the groove and the insulator, and a fifth step of forming one for each piezoelectric element. It is said.

14. The method of manufacturing a piezoelectric element according to claim 13 , wherein the second step is any one of a sputtering method, an aerosol deposition method, a chemical solution method, and a screen printing method. The piezoelectric film is formed by the above. In particular, when a film is formed by the aerosol deposition method, a large film stress (a thermal stress or a compressive stress generated at the interface with the diaphragm accompanying the film formation) acts, but the film is formed by providing a groove for separating the piezoelectric film into a plurality of parts. Stress can be reduced.

In the method for manufacturing a piezoelectric element according to claim 13 or 14 as shown in claim 15, wherein the third step, a dry etching method, to form the groove by either wet etching or nanoimprinting It is a feature. In particular, when the groove is formed by the nanoimprint method, the cross-sectional shape (for example, a triangular shape) of the groove can be formed with high accuracy.

In the method for manufacturing a piezoelectric element according to claim 13 or 14 as shown in claim 16, wherein the second and third steps, the piezoelectric film separated into a plurality using a mask corresponding to the groove The film is formed directly. That is, the second step and the third step can be performed in the same step by forming a film by a sol-gel method, a screen printing method or the like using a mask corresponding to the groove.

In the method for manufacturing a piezoelectric element according to any one of claims 13 to 16 as shown in claim 17, wherein the fourth step, after spin coating a precursor solution of the insulator on the piezoelectric film, It is characterized in that an insulator is filled in the groove portion of the piezoelectric film by surface polishing.

The liquid ejection device according to claim 18 is configured such that a liquid chamber in which a liquid is stored, a lower electrode, a piezoelectric film, and an upper electrode are sequentially stacked on a vibration plate, and the piezoelectric film is formed by the lower electrode and the upper electrode. A piezoelectric element to which an electric field is applied, wherein the piezoelectric film has a plurality of grooves for one piezoelectric element , and an insulator is provided in the groove, and the lower electrode The upper electrode is formed on the piezoelectric film and the insulator, one is formed for one piezoelectric element, and the volume of the liquid chamber is changed by deforming the diaphragm. And a nozzle that ejects the liquid in the liquid chamber when the pressure in the liquid chamber rises due to deformation of the diaphragm by the piezoelectric element.

  According to the present invention, since the piezoelectric film is separated into a plurality of parts by the groove filled with the insulator, the stress generated in the piezoelectric film itself when the diaphragm is displaced can be relieved. Can be increased, and cracking and peeling of the piezoelectric film can be prevented. Further, since the groove is filled with an insulator, this portion does not discharge between the upper electrode and the lower electrode.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a piezoelectric element, a method for manufacturing the same, and a liquid ejection device according to the present invention will be described in detail below with reference to the accompanying drawings.

[Outline of inkjet recording apparatus]
First, an outline of an ink jet recording apparatus which is one of liquid ejecting apparatuses according to the present invention will be described.

  FIG. 1 is an overall configuration diagram of an ink jet recording apparatus. As shown in the figure, the inkjet recording apparatus 10 includes a printing unit 12 having a plurality of liquid ejection heads (hereinafter simply referred to as “heads”) provided for each ink color, and ink supplied to each head. An ink storage / loading unit 14 for storing, a paper feeding unit 18 for supplying the recording paper 16, a decurling unit 20 for removing curling of the recording paper 16, and a nozzle surface (ink ejection surface) of the printing unit 12 A suction belt transport unit 22 that transports the recording paper 16 while maintaining the flatness of the recording paper 16, and a paper discharge unit 26 that discharges printed recording paper (printed matter) to the outside. It is equipped with.

  The recording paper 16 delivered from the paper supply unit 18 retains curl due to having been loaded in the magazine. In order to remove this curl, heat is applied to the recording paper 16 by the heating drum 30 in the direction opposite to the curl direction of the magazine in the decurling unit 20.

  In the case of an apparatus configuration that uses roll paper, a cutter (first cutter) 28 is provided as shown in FIG. 1, and the roll paper is cut into a desired size by the cutter 28. The cutter 28 includes a fixed blade 28A having a length equal to or greater than the conveyance path width of the recording paper 16, and a round blade 28B that moves along the fixed blade 28A. The fixed blade 28A is provided on the back side of the print. The round blade 28B is disposed on the printing surface side with the conveyance path interposed therebetween. Note that the cutter 28 is not necessary when cut paper is used.

  After the decurling process, the cut recording paper 16 is sent to the suction belt conveyance unit 22. The suction belt conveyance unit 22 has a structure in which an endless belt 33 is wound between rollers 31 and 32, and at least a portion facing the nozzle surface of the printing unit 12 forms a horizontal surface (flat surface). Has been.

  The belt 33 has a width that is greater than the width of the recording paper 16, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in FIG. 1, a suction chamber 34 is provided at a position facing the nozzle surface of the printing unit 12 inside the belt 33 spanned between the rollers 31 and 32, and the suction chamber 34 is connected to the fan 35. The recording paper 16 on the belt 33 is sucked and held by suctioning to negative pressure.

  The power of a motor (not shown) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, so that the belt 33 is driven in the clockwise direction in FIG. The recording paper 16 is conveyed from left to right in FIG.

  Since ink adheres to the belt 33 when a borderless print or the like is printed, the belt cleaning unit 36 is provided at a predetermined position outside the belt 33 (an appropriate position other than the print area).

  A heating fan 40 is provided on the upstream side of the printing unit 12 on the paper conveyance path formed by the suction belt conveyance unit 22. The heating fan 40 heats the recording paper 16 by blowing heated air onto the recording paper 16 before printing. Heating the recording paper 16 immediately before printing makes it easier for the ink to dry after landing.

  FIG. 2 is a plan view of the main part around the printing unit 12. The printing unit 12 is provided with a carriage 15 that can reciprocate along two guide rails 13 that extend in the paper width direction (main scanning direction) of the recording paper 16. The carriage 15 includes a head 23 (23K, 23C, 23M, 23Y) corresponding to each color ink of black (K), cyan (C), magenta (M), and yellow (Y), and a print detection unit (scanner unit) 24. These are configured to be detachable from the carriage 15 and can be scanned in the main scanning direction integrally with the carriage 15.

  In this example, the configuration of KCMY standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink and dark ink are added as necessary. May be. For example, it is possible to add a head for ejecting light-colored ink such as light cyan and light magenta.

  The print detection unit 24 includes a sensor (not shown in FIG. 2) for capturing a recorded image, and functions as means for reading a test pattern recorded by the head 23 and checking the ink ejection state of the head 23. That is, the print detection unit 24 can detect the variation of each nozzle included in the head 23.

  Returning to FIG. 1, a post-drying unit 42 is provided in the subsequent stage of the printing unit 12. The post-drying unit 42 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  A heating / pressurizing unit 44 is provided following the post-drying unit 42. The heating / pressurizing unit 44 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 45 having a predetermined surface uneven shape while heating the image surface to transfer the uneven shape to the image surface. To do.

  The printed matter generated in this manner is cut into a predetermined size by the cutter 48 and then discharged from the paper discharge unit 26. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 10 is provided with a sorting means (not shown) that switches the paper discharge path so as to select the print product of the main image and the print product of the test print and send them to the discharge units 26A and 26B. Yes. When the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is cut off by the cutter (second cutter) 48.

[Piezoelectric element structure]
Next, the structure of the piezoelectric element according to the present invention used for the liquid jet head or the like will be described.

  FIG. 3 is a cross-sectional view of the main part of a liquid ejection head to which the piezoelectric element according to the present invention is applied. FIGS. 3A and 3B show the non-driven state and the driven state of the diaphragm, respectively.

  In the liquid ejection head 50 shown in FIG. 3, a liquid chamber (pressure chamber) 54 is formed by the vibration plate 51, the pressure partition wall 52, and the nozzle plate 53, a lower electrode 55 is formed on the vibration plate 51, and the lower electrode 55. A piezoelectric film 56 is directly formed thereon.

  The piezoelectric film 56 is separated into a plurality of parts by a groove part (the lower part may be connected), and the groove part is filled with a polymer material (resin) 57. An upper electrode 58 is formed on the piezoelectric film 56 and the resin 57. The depth of the groove portion of the piezoelectric film 56 filled with the resin 57 is 20% to 100%, preferably 50% to 100%, more preferably 70% to 100% of the thickness of the piezoelectric film 56.

  In the liquid ejection head 50 having the above configuration, when a driving voltage is applied between the lower electrode 55 and the upper electrode 58, the piezoelectric film 56 is displaced in the d31 mode that expands and contracts in the long side direction. As a result, FIG. ), The diaphragm 51 is displaced in a concave shape.

  The displacement of the vibration plate 51 reduces the volume of the liquid chamber 54, and the liquid (ink liquid or the like) in the liquid chamber is ejected from the nozzle 53 a formed in the nozzle plate 53.

  Here, when the vibration plate 51 is displaced in a concave shape, the stress generated in the piezoelectric film itself is relieved by the resin 57 in the piezoelectric film 56, so that the vibration plate 51 can be greatly displaced. Further, since the piezoelectric film 56 is separated, it is possible to prevent the piezoelectric film 56 from being cracked or peeled off, and there is no cracking or peeling due to stress (thermal stress or the like) after the piezoelectric film is formed.

  Furthermore, since the groove portion is filled with the resin 57 that is an insulator, there is no discharge between the lower electrode 55 and the upper electrode 58.

[Piezoelectric element manufacturing method]
Next, a method for manufacturing a piezoelectric element according to the present invention will be described.

  FIG. 4 is a process diagram showing a manufacturing process of a liquid ejection head including a method for manufacturing a piezoelectric element according to the present invention.

(A) Formation of diaphragm and liquid chamber As shown in FIG. 4 (A), first, aluminum is patterned on the back surface of a silicon (Si) substrate as a mask material, and inductively coupled reactive ion etching (ICP-RIE) is performed. An anisotropic etching is performed with an apparatus to form the liquid chamber 54 and the diaphragm 51. The size of the opening (that is, the diaphragm 51) at this time was designed to be 300 μm square.

(B) Formation of Lower Electrode Next, the lower electrode 55 is formed as shown in FIG. That is, a titanium oxide layer (TiO2) having a thickness of 20 nm serving as an adhesion layer is formed on a Si substrate on which a thermal oxide film is formed by sputtering, and a platinum layer (Pt) having a thickness of 2000 nm serving as a conductive layer is formed thereon. Is formed by sputtering. The substrate temperature during each sputtering was 300 ° C.

(C) Formation of Piezoelectric Film (PZT Film) As shown in FIG. 4C, a piezoelectric film 56 of lead zirconate titanate (PZT) is directly formed on the lower electrode 55 by sputtering. The substrate temperature at this time is 550 ° C., and the film thickness of the piezoelectric film 56 is 5 μm.

  The method of directly forming the piezoelectric film 56 on the lower electrode 55 is not limited to the sputtering method, and a chemical solution method such as an aerosol deposition method or a sol-gel method, or a screen printing method may be used.

  When a piezoelectric film is formed by the sol-gel method, the film thickness is controlled by adjusting a sol-gel solution having a PZT composition and applying it on the lower electrode by spin coating, and then repeating the drying and desolvation steps. Can be formed by firing at 650 ° C. The sol-gel method is a solution film formation method by hydrolysis. Instead of the sol-gel method, the chemical solution film is formed by another chemical solution method such as an organometallic decomposition method (MOD method) which is a solution film formation method by thermal decomposition. You may make it form.

(D) Separation of Piezoelectric Film As shown in FIG. 4D, the piezoelectric film 56 is RIE dry-etched to form a groove 60, and the piezoelectric film 56 is separated into a plurality of separators 56A.

  In this embodiment, as shown in FIG. 5, a 300 μm square piezoelectric film 56 is divided into 36 × 6 × 6. The maximum width of the groove 60 is 4 μm.

  In addition, you may make it form the groove part 60 not only by dry etching but by wet etching.

  As shown in FIG. 4D, the shape of the groove portion 60 is a groove having a V-shaped cross section (V groove), but is not limited to this shape. Furthermore, each separator 56A is not limited to being completely separated, and the lower part may be connected.

  Furthermore, the shape of the separated body 56A is not limited to the square in this embodiment, but may be a stripe, rectangle, rhombus, or honeycomb. Further, when the 300 μm square piezoelectric film 56 is separated, the size of the separated separated body is preferably set so that the length of one side is 100 μm or less.

(E) Resin Filling As shown in FIG. 4 (E), the groove 60 formed in the piezoelectric film 56 is filled with a resin 57. In this embodiment, a polyimide resin, which is a thermoplastic resin, is used as the resin 57, a polyimide precursor solution is spin-coated, and after being hardened, the surface is polished by a CMP (Chemical Mechanical Polishing) apparatus, and is applied to the upper surface of the separator 56A. Remove the adhering polyimide resin.

  In addition, as an insulator which fills the groove part 60, you may use high molecular materials, such as not only a polyimide resin but a synthetic resin or silicone rubber. Synthetic resin types include photo-curing resins (such as urethane acrylate photo-curing resins and epoxy-based photo-curing resins), thermoplastic resins (such as polyimide resin, polyacetal, and polyvinylidene fluoride), and thermosetting resins (epoxy). Resin).

  This type of polymer material has a Young's modulus of several GPa, is almost an order of magnitude lower than the Young's modulus of PZT of 50 GPa or more, and has an insulating property. Therefore, it is suitable as a material for filling the groove 60. However, the present invention is not limited to this, and any insulator that has a Young's modulus smaller than that of the piezoelectric film may be used.

(F) Formation of Upper Electrode Subsequently, the upper electrode 58 is formed as shown in FIG. That is, Pt is formed on the separated piezoelectric film 56 and resin 57 by sputtering. The substrate temperature during sputtering was 100 ° C. One upper electrode 58 is formed for each piezoelectric element and is not divided like the upper electrode described in Patent Document 1.

(G) Affixing the nozzle plate Finally, as shown in FIG. 4G, the nozzle plate 53 on which the nozzles 53a are formed is affixed with an adhesive.

  The characteristics of the piezoelectric element manufactured in the liquid ejection head manufacturing process as described above were measured. That is, when the piezoelectric constant d31 was measured from the voltage applied between the lower electrode 55 and the upper electrode 58 and the displacement amount of the diaphragm 51 at that time, the piezoelectric constant d31 was 200 pm / V.

  On the other hand, when the piezoelectric constant d31 of the piezoelectric element manufactured by the same manufacturing method (without the steps of FIGS. 4D and 4E) as shown in FIG. 4 is measured except that the piezoelectric film is not separated. The piezoelectric constant d31 was 150 pm / V.

  As described above, when the piezoelectric film 56 is separated by the groove portion 60 and the groove portion 60 filled with the resin 57 is compared with the case where the piezoelectric film 56 is not separated, it can be seen that the former has a larger displacement.

  Next, another embodiment (nanoimprint method) for forming a groove for separating piezoelectric films will be described.

  As shown in FIG. 6, a mold 70 corresponding to the shape of the groove for separating the piezoelectric film is prepared. In addition, with the progress of semiconductor manufacturing technology, it is possible to manufacture a mold having a nano-order pattern.

  A piezoelectric film 72 having a desired thickness is applied on the lower electrode by a sol-gel method or the like (FIG. 6A). In this state, the piezoelectric film 72 is not sintered.

  Subsequently, the mold 70 is pressed against the piezoelectric film 72, and the pattern shape of the mold 70 is transferred to the piezoelectric film 72 (FIG. 6B).

  Thereafter, the mold 70 is peeled from the piezoelectric film 72, and the piezoelectric film 72 is sintered (FIG. 6C).

  Thereby, the groove part 74 which isolate | separates the piezoelectric film 72 can be formed. By this nanoimprint method, the cross-sectional shape of the groove 74 can be formed with high accuracy.

  The piezoelectric element according to the present invention has been described as being applied as an actuator for a liquid ejection head. However, the present invention is not limited to this, and the present invention is not limited to this. Can be applied.

  The liquid ejecting apparatus according to the present invention is not limited to an ink jet recording apparatus that ejects ink onto recording paper. For example, the liquid ejecting apparatus is an apparatus that forms an image by ejecting treatment liquid or water onto a recording medium. It can be used as an apparatus for forming an image recording medium by spraying a coating liquid onto a material. It can also be used to make electronic devices and biochips.

FIG. 1 is an overall configuration diagram of an ink jet recording apparatus which is one of liquid ejecting apparatuses according to the present invention. FIG. 2 is a plan view of the main part around the printing unit of the ink jet recording apparatus shown in FIG. FIG. 3 is a cross-sectional view of the main part of a liquid jet head to which the piezoelectric element according to the present invention is applied. 4 is a process diagram showing the manufacturing process of the liquid ejection head including the manufacturing method of the piezoelectric element according to the present invention. FIG. 5 is a diagram showing an example of the division of the piezoelectric film with respect to one piezoelectric element. FIG. 6 is a diagram used for explaining a nanoimprint method for separating piezoelectric films.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 50 ... Liquid ejection head, 51 ... Vibrating plate, 52 ... Pressure partition, 53 ... Nozzle plate, 53a ... Nozzle, 54 ... Liquid chamber (pressure chamber), 55 ... Lower electrode, 56, 72 ... Piezoelectric Membrane 57 ... Resin 58 ... Upper electrode 60 74 74 Groove 70 Mold

Claims (18)

In a piezoelectric element in which a lower electrode, a piezoelectric film, and an upper electrode are sequentially stacked on a diaphragm, and an electric field is applied to the piezoelectric film by the lower electrode and the upper electrode.
The piezoelectric film is formed by a film forming method in which a film is formed directly on the lower electrode,
The piezoelectric film has a plurality of grooves for one piezoelectric element , and includes an insulator in the grooves.
The lower electrode is formed over the diaphragm,
The upper electrode is formed on the piezoelectric film and the insulator, and one upper electrode is formed for one piezoelectric element.   The piezoelectric element according to claim 1, wherein the insulator has a lower Young's modulus than the piezoelectric film.   The piezoelectric element according to claim 2, wherein the insulator has a Young's modulus lower than 50 GPa.   The piezoelectric element according to claim 1, wherein the insulator is made of a polymer material.   The piezoelectric element according to claim 4, wherein the polymer material is synthetic resin or silicone rubber.   The piezoelectric element according to claim 5, wherein the synthetic resin is a photocurable resin, a thermoplastic resin, or a thermosetting resin.   The piezoelectric element according to any one of claims 1 to 6, wherein the groove portion has the same depth as the thickness of the piezoelectric film or a depth shallower than the thickness of the piezoelectric film.   7. The depth of the groove is 20% to 100%, preferably 50% to 100%, more preferably 70% to 100% of the thickness of the piezoelectric film. A piezoelectric element according to claim 1. 9. The piezoelectric element according to claim 1, wherein the shape of each piezoelectric film divided by the groove is any one of a stripe shape, a rectangular shape, a square shape, a rhombus shape, and a honeycomb shape.   9. The piezoelectric element according to claim 1, wherein each of the piezoelectric films separated into a plurality by the groove has a side length of 100 μm or less.   The piezoelectric element according to any one of claims 1 to 10, wherein the groove is formed by any one of a dry etching method, a wet etching method, and a nanoimprint method.   The piezoelectric film according to claim 1, wherein the piezoelectric film having the groove is formed by directly forming a plurality of separated piezoelectric films using a mask corresponding to the groove. element. A first step of forming a lower electrode over the diaphragm;
A second step of forming a piezoelectric film by a film forming method of directly forming a film on the lower electrode;
A third step of separating the piezoelectric film into a plurality of grooves , wherein a plurality of grooves are formed for one piezoelectric element ;
A fourth step of filling the groove with an insulator;
A fifth step of forming an upper electrode on the piezoelectric film and the insulator separated into a plurality by the groove, and a fifth step of forming one for one piezoelectric element;
The manufacturing method of the piezoelectric element characterized by the above-mentioned.   14. The piezoelectric film according to claim 13, wherein in the second step, the piezoelectric film is formed by any one of a sputtering method, an aerosol deposition method, a chemical solution method, and a screen printing method. Device manufacturing method.   15. The method of manufacturing a piezoelectric element according to claim 13, wherein the third step forms the groove by any one of a dry etching method, a wet etching method, and a nanoimprint method.   15. The method of manufacturing a piezoelectric element according to claim 13, wherein the second and third steps directly form a plurality of separated piezoelectric films using a mask corresponding to the groove. Method.   14. The fourth step is characterized in that the insulator is filled in the groove of the piezoelectric film by spin-coating the precursor solution of the insulator on the piezoelectric film and then polishing the surface. The method for manufacturing a piezoelectric element according to any one of 16. A liquid chamber in which liquid is stored;
A piezoelectric element in which a lower electrode, a piezoelectric film, and an upper electrode are sequentially stacked on a vibration plate, and an electric field is applied to the piezoelectric film by the lower electrode and the upper electrode. One piezoelectric element has a plurality of grooves, and an insulator is provided in the grooves, the lower electrode is formed over the diaphragm, and the upper electrode includes the piezoelectric film and the insulation A piezoelectric element formed on the body, one for each piezoelectric element, and changing the volume of the liquid chamber by deforming the diaphragm;
When the pressure in the liquid chamber rises due to deformation of the diaphragm by the piezoelectric element, a nozzle that ejects the liquid in the liquid chamber;
A liquid ejection device comprising:

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