JP2006272664A - Droplet ejection head and droplet ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a droplet ejection head which is equipped with a laminated-type pressure generating means capable of being made highly dense, downsized and sufficiently displaced. <P>SOLUTION: A piezoelectric material layer 22, which constitutes a piezoelectric element 20, a positive electrode layer 24A, and a negative electrode layer 24B are laminated along the face direction of a diaphragm 18. In manufacture, the layer 22 of a thin film formed by a deposition method is worked by a semiconductor process (dry etching), and conductive materials, which are alternately provided between the layers 22, are formed as a film by an electroplating method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a droplet discharge head and a droplet discharge device, and more specifically, discharges ink droplets from nozzles by pressurizing a liquid in a pressure chamber by a stacked pressure generating means provided on a diaphragm. The present invention relates to a droplet discharge head applied to an inkjet recording head or the like that performs printing on a recording medium, and a droplet discharge device used in an inkjet recording apparatus or the like.

A piezoelectric element used in an ink jet recording head may be a single layer type (bender type) having a structure in which a single piezoelectric layer is sandwiched between positive and negative electrodes, or a multilayer type that is displaced using the piezoelectric longitudinal effect (for example, patents) Reference 1), or a laminated type formed by cutting a paste-type piezoelectric material and a conductive material (green sheet) alternately and laminating each other in layers and cutting them to a predetermined width (for example, see Patent Document 2) )and so on.
JP-A 63-295269 JP-A-4-1052

  However, in a single layer type piezoelectric element, the piezoelectric layer has a single layer structure, so that sufficient displacement cannot be obtained, and the positive and negative electrodes are arranged separately above and below the piezoelectric layer, so that the gap between the electrodes is A large step is generated, and the wiring pattern connected to each electrode is complicated.

  On the other hand, the conventional multilayer piezoelectric element is manufactured by alternately laminating piezoelectric layers and electrode layers, so that there are many joining processes, the manufacturing process is complicated, and the cost is high. In addition, since the stacking interval cannot be easily reduced, it is difficult to achieve high density and miniaturization, and the inkjet recording head including a plurality of the piezoelectric piezoelectric elements has a large size.

  In view of the above-described facts, an object of the present invention is to provide a droplet discharge head including a stacked pressure generating unit that can be densified and miniaturized and can obtain sufficient displacement. It is another object of the present invention to provide a liquid droplet ejection apparatus that has a liquid droplet ejection head that has a simplified and miniaturized head configuration and can provide sufficient liquid droplet ejection performance at low cost.

  In order to achieve the above object, according to the first aspect of the present invention, the liquid in the pressure chamber is pressurized by the pressure generating means provided on the diaphragm, so that the liquid droplets are ejected from the nozzle communicated with the pressure chamber. In the droplet discharge head, the piezoelectric layer formed of the electrostrictive material constituting the pressure generating means and the electrode layer formed of the conductive material are laminated along the surface direction of the diaphragm. It is characterized by.

  According to the first aspect of the present invention, the piezoelectric layers and the electrode layers constituting the laminated pressure generating means are laminated along the surface direction of the diaphragm, so that the respective layers are produced without being laminated alternately. As a result, the manufacturing process is simplified, and pressure generating means capable of obtaining sufficient displacement can be integrally formed. Also, by not laminating the layers alternately, the stacking interval can be narrowed to increase the density and reduce the size.

  According to a second aspect of the present invention, in the liquid droplet ejection head according to the first aspect, the positive electrode layer and the negative electrode layer included in the electrode layer are comb-like and arranged so as to mesh with each other. Yes.

  In the invention according to claim 2, the configuration in which the piezoelectric layer and the electrode layer are stacked along the surface direction of the diaphragm is realized by arranging the positive electrode layer and the negative electrode layer in a comb-like shape and meshing with each other. However, for example, the wiring electrodes of the respective electrodes that are electrically connected to supply an electric signal to the positive electrode layer and the negative electrode layer can be easily formed in the same layer, thereby simplifying the wiring structure. be able to.

  According to a third aspect of the present invention, in the liquid droplet ejection head according to the first aspect, the positive electrode layer and the negative electrode layer included in the electrode layer are formed in a strip shape.

  In the invention described in claim 3, by making the positive electrode layer and the negative electrode layer into a strip shape, the stacking interval can be further narrowed to further increase the density and reduce the size.

  According to a fourth aspect of the present invention, in the liquid droplet ejection head according to the third aspect, the belt-like positive electrode layer, the negative electrode layer, and the piezoelectric layer are in a circular shape along the outer peripheral shape of the pressure generating means. And it is characterized by being alternately laminated in the inner and outer directions of the pressure generating means.

  In the invention described in claim 4, the belt-like positive electrode layer, the negative electrode layer, and the piezoelectric layer are alternately laminated in a circular shape along the outer peripheral shape of the pressure generating means and in the inner and outer directions of the pressure generating means. By disposing, in this pressure generating means, the positive electrode layer and the negative electrode layer having a circular shape are displaced radially outward or inward from substantially the center of the positive electrode layer and the negative electrode layer. can get.

  According to a fifth aspect of the present invention, in the liquid droplet ejection head according to the third aspect, the belt-like positive electrode layer and the negative electrode layer are arranged in a spiral shape.

  According to the fifth aspect of the present invention, the positive electrode layer and the negative electrode layer are formed in a spiral shape by arranging the belt-like positive electrode layer, the negative electrode layer, and the piezoelectric layer in a spiral shape. Therefore, a larger amount of displacement can be obtained.

  According to a sixth aspect of the present invention, in the liquid droplet ejection head according to the fourth or fifth aspect, the positive electrode layer disposed in the circumferential shape or the spiral shape at a substantially central portion of the outer shape of the pressure generating means. And the substantially center part of the negative electrode layer is arrange | positioned.

  According to the sixth aspect of the present invention, the pressure generating means is arranged at the substantially central portion of the outer shape of the pressure generating means by arranging the substantially central portions of the positive electrode layer and the negative electrode layer arranged in a circular shape or a spiral shape. The peripheral portion of the pressure generating means is displaced inward and outward in a substantially uniform manner with respect to the substantially central portion of the pressure generating means, so that the displacement operation is stabilized.

  According to a seventh aspect of the present invention, in the liquid droplet ejection head according to any one of the fourth to sixth aspects, the displacement direction of the pressure generating means is four or more.

  In the seventh aspect of the invention, by displacing the pressure generating means in four or more directions, for example, a larger amount of displacement can be obtained than in the case of displacing in two directions.

  According to an eighth aspect of the present invention, in the liquid droplet ejection head according to any one of the first to seventh aspects, the piezoelectric layer and the electrode layer are formed by a semiconductor process to form a laminated structure. It is characterized by that.

  In the invention according to claim 8, sufficient displacement can be obtained by a simple manufacturing method by forming the piezoelectric layer and the electrode layer by a semiconductor process such as a thin film, plating, etching, etc. to form a laminated structure. The pressure generating means can be formed integrally.

  According to a ninth aspect of the present invention, in the liquid droplet ejection head according to the eighth aspect, the piezoelectric layer is formed on the diaphragm and then a layered space for providing the electrode layer is formed by a semiconductor process. It is characterized by being.

  According to the ninth aspect of the present invention, the layered space for providing the electrode layer is formed by the semiconductor process after the piezoelectric layer is formed on the vibration plate, so that the monolithic structure can be obtained by such a simple manufacturing process. The laminated pressure generating means can be produced.

  According to a tenth aspect of the present invention, in the droplet discharge head according to any one of the first to seventh aspects, the piezoelectric layer and the electrode layer are formed in a laminated structure using a photolithography process. It is characterized by that.

  In the invention described in claim 10, by forming the piezoelectric layer and the electrode layer in a laminated structure using a photolithography process, the pressure generating means capable of obtaining sufficient displacement can be integrally formed by a simple manufacturing method. .

  According to an eleventh aspect of the present invention, in the droplet discharge head according to the ninth aspect, the piezoelectric layer is formed on the diaphragm via a photoresist formed by a photolithography process, and then the photoresist is formed. By removing the layer, a layered space for providing the electrode layer is formed.

  In the eleventh aspect of the present invention, a piezoelectric layer is formed on a diaphragm via a photoresist formed by a photolithography process, and thereafter, the photoresist is removed to form a layered space for providing an electrode layer. As a result, the monolithic laminated pressure generating means can be manufactured by such a simple manufacturing process.

  According to a twelfth aspect of the present invention, in the droplet discharge head according to the tenth aspect, the electrode layer is formed on the diaphragm via a photoresist formed by a photolithography process, and then the photoresist is removed. Thus, a layered space for providing the piezoelectric layer is formed.

  In the twelfth aspect of the present invention, an electrode layer is formed on the diaphragm via a photoresist formed by a photolithography process, and then the photoresist is removed to form a layered space for providing a piezoelectric layer. Thus, the monolithic laminated pressure generating means can be manufactured through such a simple manufacturing process.

  The invention according to claim 13 is the droplet discharge head according to any one of claims 1 to 12, an electrode terminal for supplying an electric signal to the electrode layer, and the electrode terminal and the electrode layer Are respectively formed on the diaphragm, and the wiring electrode and the electrode layer are connected to each other at the lower surface of the pressure generating means.

  In the invention according to claim 13, the electrode terminal and the wiring electrode are formed on the diaphragm, and the electrode layer of the wiring electrode and the pressure generating means is connected to the lower surface portion of the pressure generating means, whereby the electrode terminal and the wiring electrode are connected. Between the wiring electrode and the electrode layer does not cause a step or the like, and the formation of the electrode terminal, the formation of the wiring electrode (routing) and the connection with the electrode layer are facilitated. Simplification and improvement of manufacturability are achieved.

  According to a fourteenth aspect of the present invention, in the liquid droplet ejection head according to the thirteenth aspect, the positive electrode terminal and the negative electrode terminal included in the electrode terminal are separately formed on the diaphragm in two layers.

  In the invention described in claim 14, by forming the positive electrode terminal and the negative electrode terminal in two layers on the diaphragm, the layout of each wiring electrically connected to the positive electrode terminal and the negative electrode terminal is facilitated. .

  According to a fifteenth aspect of the present invention, in the droplet discharge head according to any one of the first to twelfth aspects, an electrode terminal for supplying an electric signal to the electrode layer is provided on a side surface of the pressure generating unit. It is characterized by being formed.

  In the invention described in claim 15, by forming the electrode terminal on the side surface of the pressure generating means, for example, when a plurality of pressure generating means are arranged in parallel on the diaphragm, the installation space for the electrode terminals is reduced, and each pressure The generating means can be arranged close to each other. Thereby, the nozzle pitch of a droplet discharge head can be made small.

  According to a sixteenth aspect of the present invention, in the liquid droplet ejection head according to any one of the first to fifteenth aspects, the pressure generating means has a substantially entire lower surface in contact with the diaphragm. It is a feature.

  In the invention described in claim 16, a simple structure having no step on the lower surface portion can be obtained by bringing the entire surface of the lower surface of the pressure generating means into contact with the diaphragm.

  According to a seventeenth aspect of the present invention, in the liquid droplet ejection head according to any one of the first to sixteenth aspects, the pressure generating means includes a plurality of sets of the positive electrode layer and the negative electrode layer, It is characterized in that the amount of displacement of the pressure generating means is adjusted by changing the timing of supplying an electric signal to each of a plurality of sets of positive electrode layers and negative electrode layers.

  In the invention according to the seventeenth aspect, it is possible to adjust the amount (size) of the droplet discharged from the nozzle by adjusting the displacement amount of the pressure generating means.

  According to an eighteenth aspect of the present invention, in the droplet discharge head according to the seventeenth aspect, each of the plurality of sets of positive electrode layers and negative electrode layers is disposed between the central portion side and the outer peripheral portion side of the pressure generating means. It is characterized by being divided into a plurality of parts.

  In the invention of claim 18, each set of the positive electrode layer and the negative electrode layer is divided into a plurality of parts between the central side and the outer peripheral side of the pressure generating means, whereby each set is individually provided. The difference in the excluded volume when driven increases, and the gradation width of the discharged droplet amount increases.

  According to a nineteenth aspect of the present invention, in the liquid droplet ejection head according to any one of the first to eighteenth aspects, the plurality of pressure generating means are provided, and the plurality of pressure generating means are provided on the diaphragm. It is characterized by being arranged adjacent to each other corresponding to the active area.

  According to the nineteenth aspect of the invention, the nozzle pitch of the droplet discharge head can be reduced by disposing the plurality of pressure generating means corresponding to the active area on the diaphragm and close to each other.

  The invention according to claim 20 is the liquid droplet ejection head according to any one of claims 1 to 19, wherein the pressure generating means is a heating element formed of a thermostrictive material instead of the electrode layer. And a base material layer formed of a material having a coefficient of thermal expansion different from that of the heating element layer instead of the piezoelectric layer.

  In the invention of claim 20, the heating element layer is formed of a heat-strain material instead of the electrode layer, and the heating element layer is formed of a material having a different thermal expansion coefficient from that of the piezoelectric layer. Even when applied to a thermal displacement type pressure generating means having a substrate layer, the same actions and effects as in claims 1 to 19 can be obtained.

  A twenty-first aspect of the invention is characterized by including the droplet discharge head according to any one of the first to nineteenth aspects.

  In the invention according to claim 21, if the liquid droplet ejection apparatus is provided with a liquid droplet ejection head having a laminated pressure generating means capable of achieving high density and miniaturization and obtaining necessary and sufficient displacement, the head The structure is simplified and miniaturized, and necessary and sufficient droplet discharge performance can be obtained at low cost.

  Since the droplet discharge head according to the present invention has the above-described configuration, it is possible to increase the density and size of the stacked pressure generating means to be mounted, and to obtain sufficient displacement. Further, since the droplet discharge device of the present invention has the above-described configuration, the head configuration of the mounted droplet discharge head is simplified and miniaturized, and sufficient droplet discharge performance can be obtained at low cost.

  Hereinafter, an ink jet recording head and an ink jet recording apparatus according to embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the outline of the inkjet recording apparatus 300 will be described with reference to FIG. The recording medium will be described as recording paper P. In FIG. 36, the conveyance direction of the recording paper P in the inkjet recording apparatus 300 is represented by an arrow S as a sub-scanning direction, and the direction orthogonal to the conveyance direction is represented by an arrow M as a main scanning direction.

  As shown in FIG. 36, the ink jet recording apparatus 300 of this embodiment includes a carriage 312 on which black, yellow, magenta, and cyan ink jet recording units 330 (the ink jet recording head 10) are mounted. The carriage 312 has a pair of brackets 314 protruding from the upstream side in the conveyance direction of the recording paper P (only one bracket 314 is shown in the figure), and circular holes formed in the pair of brackets 314 respectively. The shaft 320 erected in the main scanning direction is inserted.

  A driving pulley (not shown) and a driven pulley (not shown) constituting the main scanning mechanism 316 are disposed on both ends in the main scanning direction with respect to the carriage 312. A part of a timing belt 322 that is wound around the driving pulley and the driven pulley and travels in the main scanning direction is fixed to the carriage 312. Accordingly, when the timing belt 322 travels in the main scanning direction by the rotational driving of the driving pulley, the carriage 312 is reciprocated in the main scanning direction with the pair of brackets 314 being guided by the shaft 320.

  A paper feed tray 326 for storing recording paper P before image printing in a bundle is provided at the lower front side of the ink jet recording apparatus 300. Above the paper feed tray 326, a paper discharge tray 328 for discharging the recording paper P on which an image has been printed by the ink jet recording unit 330 for each color is provided. Also, below the carriage 312 and the shaft 320, there is a sub-scanning mechanism 318 composed of a transport roller and a discharge roller for transporting the recording paper P fed one by one from the paper feed tray 326 at a predetermined pitch in the sub-scanning direction. Is provided.

  In addition, the inkjet recording apparatus 300 is provided with a control panel 324 for performing various settings during printing, a maintenance station (not shown), and the like. The maintenance station includes a cap member, a suction pump, a dummy jet receiver, a cleaning mechanism, and the like, and performs maintenance operations such as a suction recovery operation, a dummy jet operation, and a cleaning operation.

  Further, each color ink jet recording unit 330 is configured by integrally forming the ink jet recording head 10 shown in FIG. 2 and an ink tank (not shown) for supplying ink to the ink jet recording head 10. A plurality of nozzles 12 (see FIG. 2) formed on the ink ejection surface are mounted on the carriage 312 so as to face the recording paper P. As a result, the ink jet recording head 10 selectively ejects ink droplets from the nozzles 12 onto the recording paper P while moving in the main scanning direction by the main scanning mechanism 316, whereby image data is applied to a predetermined band region. A part of the image based on is recorded.

  When one movement in the main scanning direction is completed, the recording paper P is conveyed at a predetermined pitch in the sub scanning direction by the sub scanning mechanism 318, and the ink jet recording head 10 (ink jet recording unit 330) is again moved in the main scanning direction ( A part of the image based on the image data is recorded in the next band area while moving in the opposite direction). By repeating such an operation a plurality of times, the recording paper P The entire image based on the image data is recorded in full color.

  The ink jet recording apparatus 300 is configured as described above. Next, the ink jet recording head 10 mounted on the ink jet recording apparatus 300 will be described in detail.

  FIG. 1 shows a laminated piezoelectric element 20 and a diaphragm 18 according to the first embodiment, and FIG. 2 shows an inkjet recording head 10 according to the first embodiment having the piezoelectric element 20. It is shown.

  As shown in FIG. 2, the inkjet recording head 10 is laminated from the lower side of the drawing in the order of a nozzle plate 14 on which nozzles 12 are formed, an ink pool plate 16, and a diaphragm 18, and the plates are joined together. Configured. The piezoelectric element 20 is stacked on the upper surface of the vibration plate 18 and is disposed corresponding to the pressure chamber 19 that is supplied with ink from the ink pool 17 and communicates with the nozzle 12.

  As shown in FIG. 1A, the piezoelectric element 20 is formed of a piezoelectric layer (PZT layer) 22 made of an electrostrictive material such as PZT (lead zirconate titanate) and a conductive material. The positive electrode layer 24 </ b> A and the negative electrode layer 24 </ b> B are configured by being alternately stacked along the surface direction of the diaphragm 18. Further, the positive electrode layer 24A and the negative electrode layer 24B are formed in a comb shape in a plan view and are arranged so as to mesh with each other. In the present embodiment, the width (W1) of the electrode layer 24 is 10 μm, and the distance between the electrode layers (P1) is 10 μm. The positive electrode layer 24A and the negative electrode layer 24B are collectively referred to as an electrode layer 24.

  On both sides of the piezoelectric element 20 on the vibration plate 18, a positive electrode terminal 26A serving as a positive electrode terminal and a negative terminal 26B serving as a negative electrode terminal are formed. Note that the positive terminal 26A and the negative terminal 26B are collectively referred to as an electrode terminal 26.

  The positive electrode terminal 26 </ b> A is electrically connected to the positive electrode layer 24 </ b> A of the piezoelectric element 20 through a positive electrode electrode 28 </ b> A formed in a pattern on the vibration plate 18, and the negative electrode terminal 26 </ b> B is connected to the vibration plate 18. It is electrically connected to the negative electrode layer 24B of the piezoelectric element 20 via a negative electrode electrode 28B formed in a pattern on the top. Note that the wiring electrode 28A and the wiring electrode 28B are collectively referred to as the wiring electrode 28. The wiring electrode 28 and the electrode layer 24 are connected at the lower surface of the piezoelectric element 20 as shown in FIGS. 1B and 1C, and substantially the entire lower surface of the piezoelectric element 20 (electrode layer). The region excluding 24 is in contact with the upper surface of the diaphragm 18.

  The vibration plate 18 is formed of a material having at least a non-conductive surface, and is formed of, for example, a stainless plate or a resin plate that covers an insulating film such as an oxide film.

  When the piezoelectric element 20 and the diaphragm 18 are mounted on the ink jet recording head 10 as shown in FIG. 2, a head control unit (not shown) is connected to the electrode terminal 26, and the head control unit is inputted from the outside. In response to the received image information, an electrical signal (drive signal) is transmitted to drive the piezoelectric element 20 at a predetermined timing. Thereby, the piezoelectric element 20 is displaced to deform the vibration plate 18, the ink in the pressure chamber 19 is pressurized, and the ink droplet id is ejected from the nozzle 12.

  Next, a method for manufacturing the multilayer piezoelectric element 20 according to this embodiment will be described.

  As shown in FIG. 3A, first, the electrode terminal 26 (positive electrode terminal 26A, negative electrode terminal 26B) and the wiring electrode 28 (wiring electrodes 28A, 28B) are electrically connected to the diaphragm 18 with Ir, Pb, etc. After forming a seed layer for plating, the electrode terminal 26 and the wiring electrode 28 are patterned by dry etching using a photoresist as a mask. After patterning, the electrode terminal 26 is protected by an insulating film 30 such as an oxide film.

  Next, as shown in FIG. 3B, the piezoelectric layer 22 is formed on the diaphragm 18 by sol-gel method, sputtering method, basic phase growth method, liquid phase growth method, hydrothermal synthesis method, MOCVD method, AD The film is formed by a deposition method such as an (aerosol deposition) method. After the film formation, an etching resistant film 32 such as a photoresist or Si-containing resist is formed on the piezoelectric layer 22, and an etching mask is formed by photolithography.

  Subsequently, after the piezoelectric layer 22 is patterned by dry etching, the etching resistant film 32 (etching mask) is peeled off as shown in FIG. Further, as shown in FIG. 3D, a conductive material, which is a material for forming the electrode layer 24 (positive electrode layer 24A, negative electrode layer 24B), is formed between the piezoelectric layers 22 by electroplating or the like. . Here, if it is necessary to flatten the surface of the piezoelectric layer 22, polishing is performed.

  Next, the insulating film 30 of the electrode terminal 26 is peeled off. Here, the insulating film 30 may not be peeled off, and the electrode terminal 26 may be opened in the next step.

  Finally, as shown in FIG. 3E, when an insulating film 34 such as an oxide film is formed to form openings 36A and 36B of the positive terminal 26A and the negative terminal 26B, a piezoelectric element is formed on the diaphragm 18. 20, a positive electrode terminal 26A, a negative electrode terminal 26B, and wiring electrodes 28A and 28B are formed.

  Here, a comparison of displacement between a thin film laminated piezoelectric element manufactured by the above manufacturing method and a general single layer piezoelectric element will be described.

  The piezoelectric element shown in FIGS. 4 and 5 is a laminated piezoelectric element in which the piezoelectric layers 42, the positive electrode layers 44A, and the negative electrode layers 44B are alternately laminated along the surface direction of the diaphragm 18 in the above manufacturing process. When the electrical signal is applied to the stacked piezoelectric element 40, the stacked piezoelectric element 40 is distorted outward (in the direction of arrow X1 in FIGS. 4A and 5A) in the stacking direction (polarization direction). In the direction perpendicular to the stacking direction, distortion occurs inward (in the direction of the arrow Y1 in FIGS. 4A and 5A), and is shown on the diaphragm 18 by, for example, a two-dot chain line in FIG. 4B. Is displaced in the direction of arrow Z1.

  Further, in this multilayer piezoelectric element 40, as a result of simulating the amount of displacement when 20 layers of piezoelectric layers 42 are laminated with a width (d) of 20 μm and the total width (W1) is 400 μm, the maximum displacement is obtained with the piezoelectric element alone. It was 0.106 μm (see FIG. 5A), and the maximum displacement was 0.066 μm when mounted on the Ni diaphragm 18 having a thickness of 10 μm (see FIG. 5B).

  The piezoelectric element shown in FIGS. 6 and 7 is a single layer type piezoelectric element 50 having a general configuration in which a single piezoelectric layer 52 is sandwiched between a positive electrode layer 54A and a negative electrode layer 54B. When an electric signal is applied to the piezoelectric element 50, the direction along the surface direction (direction orthogonal to the polarization direction) is all inward (the direction of the arrow X2 / Y2 in FIGS. 6A and 7A). Distortion occurs and the diaphragm 18 is displaced in the direction of the arrow Z2 as indicated by a two-dot chain line in FIG. 6B, for example.

  Further, as a result of simulating the displacement when the total width (W2) is 400 μm in this single-layer piezoelectric element 50, the maximum displacement is 0.117 μm in the single piezoelectric element (see FIG. 7A), and the thickness is 10 μm. The maximum displacement was 0.275 μm when attached to the Ni diaphragm 18 (see FIG. 7B). For ease of comparison with FIG. 5B, in FIG. 7B, the displacement direction of the single-layer piezoelectric element 50 is shown in the direction opposite to that in FIG. 6B.

  From this comparison, the multilayer piezoelectric element 40 that strains and deforms in the direction of increasing (inward) and the direction of decreasing (outward) is a single-layer piezoelectric element that strains and deforms only in the direction of increasing (inward). It can be seen that, with respect to the element 50, an equivalent displacement amount can be obtained with the piezoelectric element alone, but the displacement amount becomes smaller when attached to the diaphragm 18. (For example, the amount of displacement is about ¼ in the above simulation result). However, in the ink jet recording head, if there is the above-mentioned displacement amount, the necessary and sufficient ejection energy (pressure) can be given to the ink, so that the laminated piezoelectric element 40 can be used sufficiently.

  FIG. 8 shows an example in which the piezoelectric elements 20 of the present embodiment are arranged on the diaphragm 18 in a matrix. Here, each piezoelectric element 20 corresponds to the active region on the diaphragm 18 and is disposed close to each other, and the positive terminal 26 </ b> A and the negative terminal 26 </ b> B are formed on both side surfaces of the piezoelectric element 20. Further, the positive terminal 26A of each piezoelectric element 20 (20A, 20B, 20C...) Is connected to each address line 56 (56A, 56B, 56C...) Individually wired on the diaphragm 18, and each piezoelectric element 20 is connected. The negative electrode terminal 26 </ b> B is connected to a GND line 58 that is commonly wired on the diaphragm 18.

  As described above, the plurality of piezoelectric elements 20 having the electrode terminals 26 formed on the side surfaces thereof are arranged in close proximity to each other corresponding to the active region on the diaphragm 18 and the address lines 56 and the GND lines 58 are routed between the piezoelectric elements. Thus, the installation space for the electrode terminals 26 can be reduced, and the plurality of piezoelectric elements 20 can be arranged with high density. Thereby, the nozzle pitch of the inkjet recording head 10 can be reduced, and the resolution of the image can be increased.

  FIG. 9 shows a state where the piezoelectric element 20 of this embodiment is mounted on an ink jet recording head 60 having a configuration different from that shown in FIG. When the above-described single-layer piezoelectric element 50 is provided in the ink jet recording head 60, for example, the positive electrode layer 54A and the negative electrode layer 54B are disposed separately above and below the piezoelectric body layer 52, so that there is a large gap between the electrodes. A step is generated, and the wiring pattern connected to each electrode is complicated. On the other hand, in the piezoelectric element 20 of the present embodiment, there is no step between the positive electrode layer 24A and the negative electrode layer 24B, and therefore, between these electrode layers 24 and the electrode layer 24 to which the driving IC 62 is connected. The wiring electrode 28 can be easily routed.

  As described above, the piezoelectric element 20 included in the ink jet recording heads 10 and 60 of the present embodiment is manufactured by laminating the piezoelectric layer 22 and the electrode layer 24 along the surface direction of the diaphragm 18. In addition to simplifying the process, sufficient displacement for ink ejection can be obtained, and by not stacking the layers alternately, the stacking interval can be narrowed to increase the density and reduce the size. Therefore, in the ink jet recording apparatus 300 including the ink jet recording heads 10 and 60, the head configuration is simplified and miniaturized, and necessary and sufficient ink ejection performance can be obtained at low cost.

  In the manufacture of the piezoelectric element 20, the thin piezoelectric layer 22 formed by the deposition method is processed by a semiconductor process (dry etching), and the conductive material alternated between the piezoelectric layers is formed by an electroplating method. Accordingly, the piezoelectric element 20 capable of obtaining sufficient displacement can be formed monolithically by a simple manufacturing method.

  Further, in the piezoelectric element 20 of the present embodiment, the cost can be reduced by simplifying the manufacturing process, and the pitch between the electrodes can be narrowed, so that the displacement is stabilized. Furthermore, since the electrode can be pulled out on the diaphragm 18 on the lower surface of the piezoelectric element, the reliability of the process is improved.

  Further, in the present embodiment, the positive electrode layer 24A and the negative electrode layer 24B are comb-shaped and arranged so as to mesh with each other, so that the piezoelectric layer 22 and the electrode layer 24 are parallel to the surface direction of the diaphragm 18. The wiring electrodes 28A and 28B of the respective electrodes that are electrically connected to supply electric signals to the positive electrode layer 24A and the negative electrode layer 24B can be easily formed in the same layer while realizing a stacked structure. Thus, the wiring structure can be simplified.

  In the present embodiment, the electrode terminal 26 and the wiring electrode 28 are formed on the vibration plate 18, and the wiring electrode 28 and the electrode layer 24 of the piezoelectric element 20 are connected by the lower surface portion of the piezoelectric element 20. There is no step between the electrode terminal 26 and the wiring electrode 28 and between the wiring electrode 28 and the electrode layer 24, the formation of the electrode terminal 26, the formation (wiring) of the wiring electrode 28, and the electrode layer 24. Can be easily connected, and the wiring and connection structure can be simplified and the productivity can be improved.

  Further, in the present embodiment, since the substantially entire lower surface of the piezoelectric element 20 (the region excluding the electrode layer 24) is in contact with the diaphragm 18, a simple structure with no step on the lower surface portion can be achieved. Yes.

(Second Embodiment)
FIG. 10 shows a multilayer piezoelectric element 110 and a diaphragm 18 according to the second embodiment, and FIG. 11 shows an inkjet recording head 100 according to the second embodiment including the piezoelectric element 110. It is shown. The ink jet recording head 100 has the same configuration as that of the ink jet recording head 10 of the first embodiment except for the piezoelectric elements 110.

  As shown in FIGS. 10A to 10C, the piezoelectric element 110 of the present embodiment also includes the piezoelectric layer 112, the positive electrode layer 114 </ b> A, and the negative electrode layer 114 </ b> B along the surface direction of the diaphragm 18. Although it is configured by laminating, two sets of positive and negative electrode layers are provided. Each of the positive and negative electrode layers is formed in a rectangular spiral shape along the outer periphery of the piezoelectric element 20 in plan view, and a substantially central portion thereof is disposed at a substantially central portion of the piezoelectric element 20. In this embodiment, the positive electrode layer 114A and the negative electrode layer 114B have a width (W2) of 10 μm and an electrode interlayer distance (P2) of 10 μm.

  A positive electrode terminal 116A and a negative electrode terminal 116B are respectively formed on one side of the piezoelectric element 110 on the vibration plate 18. The positive electrode terminal 116A and the negative electrode terminal 116B are provided with a vibration plate as in the first embodiment. The positive electrode layer 114 </ b> A and the negative electrode layer 114 </ b> B of the piezoelectric element 110 are electrically connected via the patterned wiring electrodes 118 </ b> A and 118 </ b> B formed on 18. Also in this embodiment, the wiring electrodes 118A, 118B, the positive electrode layer 114A, and the negative electrode layer 114B are connected to each other at the lower surface portion of the piezoelectric element 110 as shown in FIGS. The substantially entire lower surface of the piezoelectric element 110 (the region excluding the positive electrode layer 114A and the negative electrode layer 114B) is in contact with the upper surface of the diaphragm 18.

  Next, a method for manufacturing the piezoelectric element 110 according to this embodiment will be described. As shown in FIGS. 12A to 12E, the piezoelectric element 110 is manufactured in the same process as the piezoelectric element 20 of the first embodiment.

  As shown in FIG. 12A, after the positive electrode terminal 116A, the negative electrode terminal 116B, the wiring electrodes 118A and 118B, and the seed layer for electroplating are formed on the diaphragm 18, the photoresist is used as a mask. The positive electrode terminal 116A, the negative electrode terminal 116B, and the wiring electrodes 118A and 118B are patterned by dry etching, and the positive electrode terminal 116A and the negative electrode terminal 116B are protected by the insulating film 30.

  Next, as shown in FIG. 12B, a piezoelectric layer 112 is formed on the diaphragm 18 by a deposition method, an etching resistant film 32 is formed on the piezoelectric layer 112, and a photolithography method is used. An etching mask is formed. Subsequently, after the piezoelectric layer 112 is patterned by dry etching, the etching resistant film 32 (etching mask) is peeled off as shown in FIG. 12C, and the piezoelectric layer 112 is removed as shown in FIG. A conductive material, which is a material for forming the positive electrode layer 114A and the negative electrode layer 114B, is formed between the body layers 112 by electroplating or the like. Here, if it is necessary to flatten the surface of the piezoelectric layer 112, polishing is performed, and the insulating film 30 of the positive electrode terminal 116A and the negative electrode terminal 116B is peeled off.

  Finally, as shown in FIG. 12E, an insulating film 34 such as an oxide film is formed, and openings 119A and 119B of the positive electrode terminal 116A and the negative electrode terminal 116B are formed. 110, a positive electrode terminal 116A, a negative electrode terminal 116B, and wiring electrodes 118A and 118B are formed.

  When the electric signal is applied to the thin film laminated piezoelectric element 110 of the present embodiment manufactured by the above manufacturing method, the central portion of the piezoelectric element 110 is substantially unchanged in a plan view as shown in FIG. The peripheral portion is displaced with respect to the central portion, and the displacement directions become four directions (up, down, left and right directions in FIG. 13). Further, in the stacked piezoelectric element 40 and the piezoelectric element 20 described in the first embodiment, the displacement direction is two directions (left and right direction in FIG. 14) as shown in FIG. Then, a larger amount of displacement can be obtained in the piezoelectric element 110 of the present embodiment.

  FIG. 15 shows a state in which the piezoelectric element 110 of the present embodiment is mounted on an ink jet recording head 120 having a configuration different from that in FIG. The inkjet recording head 120 has the same configuration as that of the inkjet recording head 60 of the first embodiment except for the size of the pressure chamber 19 and the constituent members except the piezoelectric element 110. Also in this case, it is easy to route the wiring electrodes 118A and 118B between the positive electrode layer 114A and the negative electrode layer 114B and the positive terminal 116A and the negative terminal 116B to which the driving IC 62 is connected.

  As described above, the piezoelectric element 110 according to the present embodiment can obtain a sufficient displacement for ejecting ink as well as the first embodiment, and can reduce the stacking interval to increase the density and reduce the size. Become. Therefore, even in the ink jet recording heads 100 and 120 including the piezoelectric element 110, the head configuration is simplified and miniaturized, and necessary and sufficient ink ejection performance can be obtained at low cost. Also in manufacturing the piezoelectric element 110, the thin piezoelectric layer 112 formed by the deposition method is processed by a semiconductor process (dry etching), and the conductive material alternated between the piezoelectric layers is formed by an electroplating method. Accordingly, the piezoelectric element 110 capable of obtaining sufficient displacement can be formed monolithically by a simple manufacturing method.

  Further, as in the first embodiment, the cost can be reduced by simplifying the manufacturing process, the stability of displacement can be improved by reducing the pitch between the electrodes, and the process by which the electrodes can be drawn on the diaphragm 18 on the lower surface of the piezoelectric element. Reliability, the simplification of the connection structure between the positive electrode terminal 116A and the negative electrode terminal 116B and the wiring electrodes 118A and 118B, and the connection between the wiring electrodes 118A and 118B and the positive electrode layer 114A and the negative electrode layer 114B, and the manufacturing associated therewith Effects such as improvement in performance and simplification of the bottom surface structure of the piezoelectric element 110 can be obtained.

  Further, in the piezoelectric element 110 according to the present embodiment, the positive electrode layer 114A and the negative electrode layer 114B having a spiral shape are displaced radially inward and outward from the substantially central portions of the negative electrode layer 114B. A quantity is obtained. Furthermore, the substantially central part of the positive electrode layer 114A and the negative electrode layer 114B arranged in a spiral shape is disposed at the substantially central part of the outer shape of the piezoelectric element 110, so that Since the portion is displaced in the inner and outer directions substantially without unevenness, the displacement operation is stabilized.

(Third embodiment)
FIG. 16 shows a laminated piezoelectric element 130 and a diaphragm 18 according to the third embodiment. The piezoelectric element 130 is a modified example in which the positive electrode terminal and the negative electrode terminal have a two-layer structure with the same configuration as the piezoelectric element 110 of the second embodiment.

  As illustrated, the positive terminal 132A is formed on the diaphragm 18, the negative terminal 132B is formed in an upper layer than the positive terminal 132A, and the positive terminal 132A and the negative terminal 132B are formed in two layers. .

  Next, a method for manufacturing the piezoelectric element 130 according to this embodiment will be described.

  As shown in FIG. 17A, after a conductive film for an electrode such as Ir or Pb is formed on the vibration plate 18, the positive electrode terminal 132A is patterned by dry etching using a resist mask. On the wiring, an interlayer insulating film 134 such as SOG or PI is applied to open the positive terminal 132A (opening 136A).

  Next, the formed opening 136A was protected by an insulating film such as SiO2 formed by LPCVD or the like, and a conductive film for an electrode such as Ir or Pb was formed as shown in FIG. Thereafter, the negative electrode terminal 132B is patterned by dry etching using a resist mask.

  Next, as shown in FIG. 17C, the formed positive electrode terminal 132A and negative electrode terminal 132B are protected by an insulating film 136 such as an oxide film, and the piezoelectric layer 112 is formed on the diaphragm 18 by a deposition method. Then, an etching resistant film 32 is formed on the piezoelectric layer 112, and an etching mask is formed by photolithography. Subsequently, after the piezoelectric layer 112 is patterned by dry etching, the etching resistant film 32 (etching mask) is peeled off as shown in FIG. 17D, and the piezoelectric layer 112 is removed as shown in FIG. A conductive material, which is a material for forming the positive electrode layer 114A and the negative electrode layer 114B, is formed between the body layers 112 by electroplating or the like. Here, if it is necessary to flatten the surface of the piezoelectric layer 112, polishing is performed, and the insulating film 136 of the positive electrode terminal 132A and the negative electrode terminal 132B is peeled off.

  Finally, as shown in FIG. 17F, an insulating film (protective film) 34 such as an oxide film is formed, and the insulating film 34 is left only at the piezoelectric element 130.

  Through the above process, the piezoelectric element 130 of this embodiment and the positive electrode terminal 132A and the negative electrode terminal 132B having a two-layer structure are manufactured. In the configuration of the present embodiment, the positive electrode terminal 132A and the negative electrode terminal 132B are separately formed on the diaphragm 18 in two layers, so that the layout of each wiring connected to the positive electrode terminal 132A and the negative electrode terminal 132B can be made. It becomes easy.

(Fourth embodiment)
In the fourth embodiment, a case where so-called “drop modulation” for changing the size of ink droplets, which is used as an effective means for achieving both high image quality and high speed in the configuration of the third embodiment, will be described. .

  In the present embodiment, as shown in FIG. 18, in the positive electrode layer 114 </ b> A and the negative electrode layer 114 </ b> B provided in two sets on the piezoelectric element 130, a set of positive and negative electrode layers arranged on the inner side of the piezoelectric element 130 ( 1) A set of positive and negative electrode layers arranged on the outside side is set as (2) set, and as shown in FIG. 19, signal generators 140A and 140B, amplifiers 142A and 142B, circuit switch 144A, 144B is provided. The circuit switches 144A and 144B are switched ON / OFF by the controller 146, respectively. Here, the controller 146 performs ON / OFF control of the circuit switches 144A and 144B, whereby (1) a set of positive electrode layers 114A and a negative electrode layer 114B and (2) a set of positive electrode layers 114A and a negative electrode. Electric signals are respectively supplied to the layers 114B, and the piezoelectric elements (piezoelectric layers 112) corresponding to the respective groups can be individually displaced.

  FIG. 20 shows the displacement of the piezoelectric element 130 when an electric signal is supplied to each pair of the positive electrode layer 114A and the negative electrode layer 114B. (1) When an electric signal is supplied only to the pair of positive electrode layer 114A and negative electrode layer 114B, the vicinity of the central portion of the piezoelectric element 130 is slightly displaced and discharged from the nozzle 12 as shown by the dotted line in the figure. The ink drop id is smaller. In addition, when an electric signal is supplied only to (2) the pair of positive electrode layer 114A and negative electrode layer 114B, almost the entire piezoelectric element 130 is displaced by a small average on average, as shown by a one-dot chain line in the figure. The ink droplet id has a medium size. Further, when electric signals are supplied simultaneously to the positive electrode layer 114A and the negative electrode layer 114B in the (1) and (2) sets, as shown by the solid line in the figure, the vicinity of the center of the piezoelectric element 130 is greatly displaced. However, the ink droplet id increases.

  As described above, in this embodiment, the pressure state of the pressure chamber 19 by the piezoelectric element 130 is switched to three types, and the ink droplet size is adjusted in three stages (drop modulation). It is possible to achieve compatibility. In addition, here, the (1) set of the positive electrode layer 114A and the negative electrode layer 114B is divided and arranged on the center side of the piezoelectric element 130, and the (2) set is divided on the outer peripheral side of the piezoelectric element 130. As a result, the difference in excluded volume when each set is driven individually is increased, and the gradation width of the drop amount is increased.

  Next, modified examples of the manufacturing method of the multilayer piezoelectric element described above in the fifth to ninth embodiments will be described.

(Fifth embodiment)
In the manufacturing method according to the fifth embodiment, as shown in FIG. 21A, first, an orientation control layer 151 such as STO is formed on the diaphragm 18.

  Next, as shown in FIGS. 21B and 21B ', the wiring electrodes 152A and 152B on the positive electrode side and the negative electrode side are patterned to cover the insulating layer, and as shown in FIG. 21C. Then, a convex portion by the photoresist 154 is formed. Subsequently, as shown in FIG. 21D, the piezoelectric layer 156 is formed (sol-gel) and baked, and as shown in FIG. 21E, patterning and photo processing of the piezoelectric layer 156 are performed. The resist 154 (convex portion) is removed. Also, here, polishing is performed if necessary.

  Next, as shown in FIG. 22A, a seed layer 160 for electroplating is formed using a mask 158. Further, as shown in FIG. 22B, a conductive material paste is filled between the piezoelectric layers 156 and fired, or electrodes 162 are embedded by electroforming, plating, or the like. Then, as shown in FIGS. 22C and 22C, polishing is performed to complete the thin film stacked piezoelectric element 150.

  As described above, the piezoelectric element 150 can be obtained with sufficient displacement and high density and miniaturization by a simple process even by the method of forming the piezoelectric layer and the electrode layer in a laminated structure using a photolithography process. It can be formed integrally.

(Sixth embodiment)
In the manufacturing method according to the sixth embodiment, steps (A), (B), and (B ′) in FIG. 23 are the same as steps (A), (B), and (B ′) in FIG. Then, as shown in FIG. 23C, a photoresist 164 is formed and patterned. Next, as shown in FIG. 23 (D), a seed layer 160 for electroplating is formed and, as shown in FIG. 23 (E), baking is performed after filling the paste between the photoresists 164, or The electrode 162 is embedded using electroforming, plating, or the like. Further, as shown in FIG. 24A, the photoresist 164 is removed, and as shown in FIG. 24B, a piezoelectric layer 156 is formed by a deposition method (sputtering, sol-gel, AD, etc.). . Finally, as shown in FIGS. 24C and 24C, polishing is performed to complete the thin film stacked piezoelectric element 170.

  As described above, the manufacturing method using the photolithographic process according to the present embodiment can integrally form the piezoelectric element 170 capable of obtaining sufficient displacement and high density and miniaturization in a simple process. it can.

(Seventh embodiment)
In the manufacturing method according to the seventh embodiment, steps (A), (B), (B ′) in FIG. 25 are the same as steps (A), (B), (B ′) in FIG. Then, as shown in FIG. 25C, the internal electrode constituent portion is patterned by forming a photoresist 172, and as shown in FIG. 25D, the piezoelectric layer 156 is formed (sputtering). To do. Next, as shown in FIG. 25E, the photoresist 172 is removed, and as shown in FIG. 26A, a seed layer 160 for plating is formed using a mask 174, and FIG. As shown in B), the electrode 162 is embedded. Finally, as shown in FIGS. 26C and 26C, polishing is performed to complete the thin film stacked piezoelectric element 180.

  As described above, the manufacturing method using the photolithographic process of the present embodiment can integrally form the piezoelectric element 180 that can obtain sufficient displacement and can be densified and miniaturized by a simple process. it can.

(Eighth embodiment)
In the manufacturing method according to the eighth embodiment, as shown in FIG. 27A, the orientation control layer 151 is formed after the barrier layer 182 is formed on the vibration plate 18 (Si substrate). The subsequent steps of FIGS. 27 (B), (B ′) to FIG. 28 (C), (C ′) are the same as the steps of FIG. 21 (B), (B ′) to FIG. 22 (C), (C ′). Thus, the thin film laminated piezoelectric element 190 provided with the barrier layer 180 is manufactured. In the manufacturing method of the present embodiment, the barrier layer 182 is provided on the vibration plate 18, thereby preventing thermal diffusion to the vibration plate 18 when the piezoelectric layer 156 is fired.

(Ninth embodiment)
In the manufacturing method according to the ninth embodiment, as shown in FIGS. 29A and 29A, first, the wiring electrodes 192A and 192B are patterned on the diaphragm 18, and FIGS. B ′), a stopper layer 194 and an orientation control layer 151 are formed. Next, as shown in FIGS. 29 (C) and (C ′), a pattern of the orientation control layer 151 is formed, and as shown in FIGS. 29 (D) and (D ′), an electrode is formed by a photoresist 196. A pattern of 198A is formed. Next, as shown in FIGS. 30A and 30A, an electrode 198A is embedded, and as shown in FIGS. 30B and 30B, the photoresist 196 is removed. Next, as shown in FIGS. 30C and 30C, a piezoelectric layer 156 is formed by a deposition method, and as shown in FIGS. 31A and 31A, a stopper after polishing is formed. Layer 200 is deposited to form the pattern of electrode 198B. Further, as shown in FIGS. 31B and 31B, the piezoelectric layer 156 is etched, and as shown in FIGS. 31C and 31C, an electrode 198B is embedded and polished. Then, a thin film laminated piezoelectric element 210 as shown in FIG. 32 is completed.

  As described above, the manufacturing method using the photolithographic process according to the present embodiment can integrally form the piezoelectric element 210 that can obtain sufficient displacement and can be densified and miniaturized in a simple process. it can.

(Tenth embodiment)
In the tenth embodiment, the present invention is applied not to the piezoelectric pressure generating means (piezoelectric element) as described in the first to ninth embodiments but to the thermal displacement type pressure generating means using a heating element. Hereinafter, the configuration of the pressure generating means according to the tenth embodiment will be described.

  FIGS. 34A to 34C show a thermal displacement type pressure generating element 220 according to the tenth embodiment. The pressure generating element 220 is formed based on the shape of the piezoelectric element 20 described in the first embodiment (see FIG. 1), and is a heating element layer formed of a thermostrictive material instead of the electrode layer 24. 224 and a base material layer 222 formed of a material having a different thermal expansion coefficient (low thermal expansion coefficient) from that of the heating element layer 224 instead of the piezoelectric layer 22, and the heating element layer 224 and the base layer 222. The material layers 222 are configured by being alternately stacked along the surface direction of the diaphragm 18. In addition, the heating element layer 224 is formed in a band shape (linear shape) in a plan view as shown in FIG. 34A, and is formed in a pattern on the diaphragm 18 as shown in FIG. The wiring electrode 28C is provided and electrically connected to the wiring electrode 28C. In this embodiment, the width (W3) of the heating element layer 224 is set to 5 μm or less, and the heating element interlayer distance (P3) is set to 10 μm or less. In addition, a metal material such as tantalum, nickel alloy, or chromium can be used for the heating element layer 224, and a glass material (evaporation), a polymer material, a polyimide resin material, an epoxy material, for example, can be used for the base material layer 222. A material having a different thermal expansion coefficient (low thermal expansion coefficient) from the heating element layer 224 such as a resin material or an oxide film, and a manufacturing process different from that of the additive can be used.

  A wiring electrode 28A connected to the positive terminal 26A and a wiring electrode 28B connected to the negative terminal 26B are connected to both ends of the wiring electrode 28C, respectively. Also in this embodiment, the wiring electrode 28C and the heating element layer 224 are connected to each other at the lower surface portion of the pressure generating element 220 as shown in FIG. The entire surface (region excluding the heating element layer 224) is in contact with the upper surface of the diaphragm 18.

  Next, a method for manufacturing the pressure generating element 220 according to this embodiment will be described.

  As shown in FIG. 34A, first, the positive electrode terminal 26A, the negative electrode terminal 26B, and the wiring electrodes 28A, 28B, and 28C and the wiring electrodes 28A, 28B, and 28C are not shown on the diaphragm 18 with Ir, Pb, or the like. ) Are then patterned by dry etching using a photoresist as a mask. After patterning, the positive electrode terminal 26A and the negative electrode terminal 26B are protected by an insulating film 30 such as an oxide film.

  Next, as shown in FIG. 34B, a material for forming the base material layer 222 is formed on the vibration plate 18 by coating, a deposition method, a vapor deposition method, or the like. After the film formation, an etching resistant film 226 such as a photoresist or a Si-containing resist is formed on the base material layer 222, and an etching mask is formed by a photolithography method.

  Subsequently, after patterning the base material layer 222 by dry etching, the etching resistant film 226 (etching mask) is peeled off as shown in FIG. Further, as shown in FIG. 34D, a metal material such as tantalum, nickel alloy, or chromium, which is a material for forming the heating element layer 224, is formed between the base material layers 222 by a deposition method, a vapor deposition method, a sputtering method, or the like. The film is formed by Here, if it is necessary to flatten the surface of the heating element layer 224, polishing is performed.

  Next, the insulating film 30 of the positive electrode terminal 26A and the negative electrode terminal 26B is peeled off. Here, the insulating film 30 may not be peeled, and the positive electrode terminal 26A and the negative electrode terminal 26B may be opened in the next step.

  Finally, as shown in FIG. 34E, an insulating film (protective film) 34 such as an oxide film is formed to form openings 36A and 36B for the positive terminal 26A and the negative terminal 26B. In addition, the pressure generating element 220, the positive terminal 26A, the negative terminal 26B, and the wiring electrodes 28A, 28B, and 28C are formed.

  As described above, the pressure generating element 220 is mounted on the ink jet recording head, the head control unit is connected to the positive terminal 26A and the negative terminal 26B, and an electric signal (driving signal) is applied / stopped from the head control unit to the pressure generating element 220. Then, the heating element layer 224 becomes high temperature / normal temperature and is distorted more than the base material layer 222, and as shown in FIG. 35, distortion occurs in the stacking direction (arrow X3 direction in FIG. 35). 18 is displaced in the direction of arrow Z3 as indicated by a two-dot chain line in FIG. Further, the pressure generating element 220 is configured to be maintained in a flat plate shape when the heating element layer 224 becomes high temperature and to be displaced when the temperature becomes normal temperature. The vibration plate 18 is deformed by the displacement of the pressure generating element 220, the ink in the pressure chamber is pressurized, and ink droplets are ejected from the nozzles of the ink jet recording head.

  As described above, in the pressure generating element 220 of the present embodiment as well, as in the first embodiment, sufficient displacement for ink ejection can be obtained, and the stacking interval can be narrowed to increase the density and reduce the size. It becomes like this. Therefore, in the case of an ink jet recording head provided with this pressure generating element 220, the head configuration is simplified and miniaturized, and necessary and sufficient ink ejection performance can be obtained at low cost. Also in the production of the pressure generating element 220, the base material layer 222 formed by the deposition method is processed by a semiconductor process (dry etching), and thin heating element layers 224 alternately formed between the base material layers are formed by the semiconductor process. By forming the film, the pressure generating element 220 capable of obtaining sufficient displacement can be formed monolithically by a simple manufacturing method.

  Further, as in the first embodiment, the cost can be reduced by simplifying the manufacturing process, the stability of displacement can be improved by reducing the pitch between the electrodes, and the process by which the electrodes can be drawn on the diaphragm 18 on the lower surface of the piezoelectric element. Reliability, and a simple connection structure between the positive electrode terminal 26A, the negative electrode terminal 26B and the wiring electrodes 28A and 28B, between the wiring electrodes 28A and 28B and the wiring electrode 28C, and between the wiring electrode 28C and the heating element layer 224. As a result, it is possible to obtain the effects such as the improvement of manufacturability and the accompanying improvement in manufacturability and the simplification of the lower surface structure of the pressure generating element 220. As described above, the pressure generating means of the thin film stack type according to the present invention is not limited to the piezoelectric type using the electrostrictive material, but uses a material that generates strain by applying energy, such as a thermal displacement type using the thermostrictive material. Anything can be used.

  As mentioned above, although the present invention was explained in detail by the 1st-10th embodiment mentioned above, the present invention is not limited to those embodiments, and other various forms are within the scope of the present invention. It can be implemented.

  For example, in the piezoelectric elements described in the first to ninth embodiments, SBT (Strontium Bismuth Tantalates) or BST that can be patterned by sol-gel deposition and dry etching, for example, as an electrostrictive material for forming a piezoelectric layer. (Barium Strontium Titanate) etc. can also be used.

  Further, in the second to fourth embodiments, the strip-like positive electrode layer 114A and the negative electrode layer 114B are arranged in a spiral shape, but instead, in a circular shape along the outer peripheral shape of the piezoelectric element, In addition, the piezoelectric elements may be alternately stacked in the inner and outer directions, and the same action and effect can be obtained. Further, the spiral and circular positive electrode layer 114A and the negative electrode layer 114B are not limited to a rectangular shape (quadrangle), for example, a polygonal shape of a pentagon or more, an arc shape, a circular shape, etc. In that case, the displacement direction of the piezoelectric element becomes five or more directions, and a larger displacement amount can be obtained.

  Further, the thermal displacement type pressure generating element 220 described in the tenth embodiment can be configured in the same manner as in the second to fourth embodiments, thereby obtaining the same operation and effect. be able to.

  The present invention is not limited to the above-described ink jet recording head and ink jet recording apparatus, and other liquid droplet ejection heads and liquid droplet ejections used in pattern forming apparatuses that eject liquid droplets for pattern formation of semiconductors and the like. It can also be applied to devices.

(A) which shows the piezoelectric element which concerns on the 1st Embodiment of this invention is a top view, (B) is the 1B-1B sectional view taken on the line of (A), (C) is the 1C-1C sectional view taken on the line of (A). It is. It is sectional drawing which shows the inkjet recording head which concerns on the 1st Embodiment of this invention provided with the piezoelectric element of FIG. (A)-(E) is a manufacturing process figure which shows the manufacturing process of the piezoelectric element of FIG. (A) is a perspective view showing a multilayer piezoelectric element corresponding to the first embodiment of the present invention, (B) is a sectional view showing a displacement operation. 4A is a perspective view showing a displacement state of the piezoelectric element alone, and FIG. 5B is a perspective view showing a displacement state in a state where it is attached to a diaphragm. (A) is a perspective view which shows a single layer type piezoelectric element, (B) is sectional drawing which shows displacement operation | movement. 6A is a perspective view showing a displacement state of a single piezoelectric element, and FIG. 7B is a perspective view showing a displacement state when attached to a diaphragm. FIG. It is a top view which shows the example which has arrange | positioned the piezoelectric element of FIG. 1 in matrix form. It is sectional drawing which shows the other inkjet recording head provided with the piezoelectric element of FIG. (A) which shows the piezoelectric element which concerns on the 2nd Embodiment of this invention is a top view, (B) is the 10B-10B sectional view taken on the line of (A), (C) is the 10C-10C sectional view taken on the line of (A). It is. It is sectional drawing which shows the inkjet recording head which concerns on the 2nd Embodiment of this invention provided with the piezoelectric element of FIG. (A)-(E) is a manufacturing process figure which shows the manufacturing process of the piezoelectric element of FIG. It is a top view which shows the displacement operation | movement of the piezoelectric element of FIG. It is a top view which shows the displacement operation | movement of the piezoelectric element of FIG. It is sectional drawing which shows the other inkjet recording head provided with the piezoelectric element of FIG. (A) which shows the piezoelectric element which concerns on the 3rd Embodiment of this invention is a top view, (B) is the 16B-16B sectional view taken on the line of (A), (C) is the 16C-16C sectional view taken on the line of (A) It is. (A)-(F) are the manufacturing process diagrams which show the manufacturing process of the piezoelectric element of FIG. (A) which shows the piezoelectric element which concerns on the 4th Embodiment of this invention is a top view, (B) is the 18B-18B sectional view taken on the line of (A), (C) is the 18C-18C sectional view taken on the line of (A) It is. It is a circuit diagram which shows schematic structure of the drive circuit which drives the piezoelectric element which concerns on the 4th Embodiment of this invention. It is sectional drawing which shows the displacement operation | movement of the piezoelectric element which concerns on the 4th Embodiment of this invention. (A)-(E) are manufacturing process diagrams which show the manufacturing process of the piezoelectric element which concerns on the 5th Embodiment of this invention. (A)-(C) are manufacturing process diagrams which show the manufacturing process of the piezoelectric element which concerns on the 5th Embodiment of this invention. (A)-(E) are manufacturing process drawings which show the manufacturing process of the piezoelectric element which concerns on the 6th Embodiment of this invention. (A)-(C) are manufacturing process diagrams which show the manufacturing process of the piezoelectric element which concerns on the 6th Embodiment of this invention. (A)-(E) are manufacturing process diagrams which show the manufacturing process of the piezoelectric element which concerns on the 7th Embodiment of this invention. (A)-(C) are manufacturing process diagrams which show the manufacturing process of the piezoelectric element which concerns on the 7th Embodiment of this invention. (A)-(E) are manufacturing process diagrams which show the manufacturing process of the piezoelectric element which concerns on the 8th Embodiment of this invention. (A)-(C) are manufacturing process diagrams which show the manufacturing process of the piezoelectric element which concerns on the 8th Embodiment of this invention. (A), (A ')-(D), (D') is a manufacturing process figure which shows the manufacturing process of the piezoelectric element which concerns on the 9th Embodiment of this invention. (A), (A ')-(C), (C') is a manufacturing process figure which shows the manufacturing process of the piezoelectric element which concerns on the 9th Embodiment of this invention. (A), (A ')-(C), (C') It is a manufacturing-process figure which shows the manufacturing process of the piezoelectric element which concerns on the 9th Embodiment of this invention. It is a fragmentary sectional perspective view which shows the piezoelectric element which concerns on the 9th Embodiment of this invention. (A) which shows the thermal displacement type pressure generating element which concerns on the 10th Embodiment of this invention is a top view, (B) is the 33B-33B sectional view taken on the line of (A), (C) is 33C of (A). It is -33C sectional view taken on the line. (A)-(E) is a manufacturing process figure which shows the manufacturing process of the pressure generating element of FIG. It is sectional drawing which shows the displacement operation | movement of the pressure generating element of FIG. 1 is a perspective view illustrating an appearance of an ink jet recording apparatus according to an embodiment of the present invention.

Explanation of symbols

10 Inkjet recording head (droplet ejection head)
12 Nozzle 18 Diaphragm 19 Pressure chamber 20 Piezoelectric element (pressure generating means)
22 Piezoelectric layer 24 Electrode layer 24A Positive electrode layer 24B Negative electrode layer 26 Electrode terminal 26A Positive electrode terminal 26B Negative electrode terminal 28 Wiring electrode 28A Wiring electrode 28B Wiring electrode 28C Wiring electrode 40 Multilayer piezoelectric element (pressure generating means)
42 Piezoelectric layer 44A Positive electrode layer 44B Negative electrode layer 60 Inkjet recording head (droplet ejection head)
100 Inkjet recording head (droplet ejection head)
110 Piezoelectric element (pressure generating means)
112 Piezoelectric layer 114A Positive electrode layer 114B Negative electrode layer 116A Positive electrode terminal 116B Negative electrode terminal 118A Wiring electrode 118B Wiring electrode 120 Inkjet recording head (droplet ejection head)
130 Piezoelectric element (pressure generating means)
132A Positive terminal 132B Negative terminal 150 Piezoelectric element (pressure generating means)
152A Wiring electrode 152B Wiring electrode 156 Piezoelectric layer 162 Electrode 170 Piezoelectric element (pressure generating means)
180 Piezoelectric element (pressure generating means)
190 Piezoelectric element (pressure generating means)
192A Wiring electrode 192B Wiring electrode 198A Electrode 198B Electrode 210 Piezoelectric element (pressure generating means)
220 Pressure generating element (pressure generating means)
222 base material layer 224 heating element layer 300 ink jet recording apparatus P recording paper id ink droplet (droplet)

Claims (21)

In a liquid droplet ejection head that ejects liquid droplets from a nozzle communicated with the pressure chamber by pressurizing the liquid in the pressure chamber by a pressure generating means provided on the diaphragm,
A droplet discharge characterized in that a piezoelectric layer formed of an electrostrictive material constituting the pressure generating means and an electrode layer formed of a conductive material are laminated along the surface direction of the diaphragm. head.   2. The liquid droplet ejection head according to claim 1, wherein the positive electrode layer and the negative electrode layer provided in the electrode layer are comb-shaped and arranged so as to mesh with each other.   2. The liquid droplet ejection head according to claim 1, wherein the positive electrode layer and the negative electrode layer included in the electrode layer are formed in a strip shape.   The belt-like positive electrode layer, the negative electrode layer, and the piezoelectric layer have a circular shape along the outer peripheral shape of the pressure generating means, and are alternately stacked in the inner and outer directions of the pressure generating means. The droplet discharge head according to claim 3.   4. The droplet discharge head according to claim 3, wherein the belt-like positive electrode layer and the negative electrode layer are arranged in a spiral shape.   The substantially central portion of the positive electrode layer and the negative electrode layer disposed in the circular shape or the spiral shape is disposed at a substantially central portion of the outer shape of the pressure generating means. 6. A droplet discharge head according to 5.   The liquid droplet ejection head according to any one of claims 4 to 6, wherein the displacement direction of the pressure generating means is four or more.   8. The droplet discharge head according to claim 1, wherein the piezoelectric layer and the electrode layer are formed by a semiconductor process to form a laminated structure.   9. The liquid droplet ejection head according to claim 8, wherein the piezoelectric layer is formed on the diaphragm and then a layered space for providing the electrode layer is formed by a semiconductor process.   8. The liquid droplet ejection head according to claim 1, wherein the piezoelectric layer and the electrode layer are formed in a laminated structure using a photolithography process.   The piezoelectric layer is formed on the diaphragm via a photoresist formed by a photolithography process, and then the photoresist is removed to form a layered space for providing the electrode layer. The droplet discharge head according to claim 10.   The electrode layer is formed on the diaphragm via a photoresist formed by a photolithography process, and then the photoresist is removed to form a layered space for providing the piezoelectric layer. The droplet discharge head according to claim 10.   An electrode terminal for supplying an electric signal to the electrode layer, and a wiring electrode for electrically connecting the electrode terminal and the electrode layer are formed on the diaphragm, respectively, and the wiring electrode and the electrode layer are The liquid droplet ejection head according to claim 1, wherein the liquid droplet ejection head is connected at a lower surface portion of the pressure generating means.   14. The liquid droplet ejection head according to claim 13, wherein a positive electrode terminal and a negative electrode terminal included in the electrode terminal are formed in two layers on the diaphragm.   13. The liquid droplet ejection head according to claim 1, wherein an electrode terminal for supplying an electric signal to the electrode layer is formed on a side surface of the pressure generating means.   16. The droplet discharge head according to claim 1, wherein the pressure generating unit has a substantially entire lower surface in contact with the vibration plate.   A plurality of sets of the positive electrode layer and the negative electrode layer are provided in the pressure generating means, and the pressure generating means is changed by changing the timing of supplying an electric signal to each of the plurality of sets of the positive electrode layer and the negative electrode layer. The liquid droplet ejection head according to claim 1, wherein the displacement amount of the liquid droplet is adjusted.   18. The droplet discharge according to claim 17, wherein each of the plurality of sets of positive electrode layers and negative electrode layers is divided into a plurality of portions between a central portion side and an outer peripheral portion side of the pressure generating means. head.   19. The apparatus according to claim 1, further comprising a plurality of the pressure generating units, wherein the plurality of pressure generating units correspond to an active region on the diaphragm and are arranged close to each other. The droplet discharge head according to Item.   The pressure generating means includes a heating element layer formed of a thermostrictive material instead of the electrode layer, and a base material layer formed of a material having a thermal expansion coefficient different from that of the heating element layer instead of the piezoelectric layer. The liquid droplet ejection head according to claim 1, wherein   A droplet discharge apparatus comprising the droplet discharge head according to claim 1.

Images