JP2012218156A - Liquid injection head and method for manufacturing actuator device for the liquid injection head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in which stress concentration is apt to occur in a boundary between a displacement portion and a non-displacement portion of a piezoelectric element, causing a failure.SOLUTION: A flow passage forming substrate including predetermined flow passages corresponding a plurality of nozzles is held between a nozzle plate having the nozzles and a vibration plate, and the piezoelectric element is disposed on the surface opposite to the flow passage forming substrate in the vibration plate in conformation to each flow passage. When a predetermined drive signal is given to the piezoelectric element, the piezoelectric element is displaced, and liquid filled in a predetermined flow passage of the flow passage forming substrate, such as ink corresponding to each flow passage, is discharged through the nozzle. When the piezoelectric element is laminated and formed on the vibration plate by semiconductor process, a weight material composed of a metallic member adjacent to the piezoelectric element is formed. Although a site subjected to stress concentration is caused during repeated displacement of the piezoelectric element, the formation of the weight material allows the piezoelectric element to resist the stress concentration.

Description

  The present invention relates to a method of manufacturing a liquid ejecting head that ejects liquid from a nozzle opening and an actuator device for the liquid ejecting head.

A liquid ejecting head that ejects liquid is provided with a piezoelectric element on one side of a flow path forming substrate provided with a pressure generating chamber that communicates with a nozzle opening. Inkjet recording heads that eject ink droplets from nozzle openings are known.
As an ink jet recording head, a flow path forming substrate in which predetermined flow paths corresponding to a plurality of nozzles are formed is sandwiched between the nozzle plate in which the nozzle is formed and a vibration plate. On the opposite surface, there is known one in which a piezoelectric element is disposed corresponding to each flow path. (For example, refer to Patent Document 1).

JP 2009-208462 A

However, in the case where the piezoelectric element is disposed on the diaphragm by a semiconductor process, there is a possibility that stress is likely to concentrate on the boundary between the displaced portion and the non-displaced portion of the piezoelectric element.
In view of such circumstances, the present invention provides a method of manufacturing a liquid ejecting head and an actuator device for the liquid ejecting head that make it difficult for stress concentration to occur when a piezoelectric element is disposed on a diaphragm by a semiconductor process.

  In an aspect of the present invention that solves the above problem, a flow path forming substrate on which predetermined flow paths corresponding to a plurality of nozzles are formed is sandwiched between a nozzle plate on which the nozzles are formed and a vibration plate, and the flow in the vibration plate is determined. Piezoelectric elements are arranged on the surface opposite to the path forming substrate corresponding to each flow path. When a predetermined drive signal is given to the piezoelectric element, the piezoelectric element is displaced, and the predetermined flow of the flow path forming board is determined. The liquid filled in the flow path is discharged from the nozzle.

Here, when the piezoelectric element is laminated on the diaphragm by a semiconductor process, a weight material made of a metal member adjacent to the piezoelectric element is formed. A portion where stress is likely to be concentrated occurs when the displacement of the piezoelectric element is repeated, but by forming a weight material, it becomes possible to withstand the stress concentration.
A specific example in which the weight material is effectively used will be described. A bottom electrode and a top electrode are disposed to apply a drive signal to the piezoelectric element. The bottom electrode is common, and a plurality of piezoelectric elements are disposed thereon. At this time, in the piezoelectric element, a part on the bottom electrode and a part where the bottom electrode is disconnected are generated. Since the part on the bottom electrode is displaced, and the part where the bottom electrode is disconnected is not displaced, the stress tends to concentrate on this boundary. For this reason, the weight material is formed so as to straddle the portion on the bottom electrode of the piezoelectric element and the portion where the bottom electrode is cut off, so that it acts to suppress the stress concentration portion and suppresses the displacement on the displacement side. For the non-displacement side, the force is suppressed even if the displacement is received. That is, the stress concentration is dispersed so that the displacement gradually occurs from the displaced portion to the non-displaced portion.

Further, on the bottom electrode formed as a common electrode in a predetermined range, a plurality of the piezoelectric elements are formed at predetermined intervals so as to intersect the bottom electrode, and the weight material is adjacent to the piezoelectric element. May be formed in common.
Thus, the bottom electrode is formed as a common electrode in a predetermined range, and a plurality of the piezoelectric elements are formed so as to intersect the bottom electrode with a predetermined interval. For this reason, a weight material can be formed in common between adjacent piezoelectric elements.

Further, in the case of manufacturing by a semiconductor process, each piezoelectric element is formed to have a trapezoidal cross section in which the upper surface becomes narrower as the distance from the diaphragm is increased, and the side wall portion is formed to be inclined. At this time, by forming the weight material so as to cover the same side wall portion between the adjacent piezoelectric elements, the stress concentration portion in each piezoelectric element can be pressed more firmly.
Further, the weight material may be formed in a wide shape on the bottom electrode and gradually narrower toward the side where the bottom electrode is cut off. Since the degree of stress concentration is not always constant, the width is formed on the bottom electrode having a large displacement in order to adjust the effect of pressing. The shape is narrow.

  The idea of the present invention can also be applied in the process of forming a piezoelectric element by a semiconductor process, and from that viewpoint, the flow path forming substrate in which a predetermined flow path portion in the liquid ejecting head is formed is provided in the same flow path portion. A manufacturing method of an actuator device in which a piezoelectric element for generating pressure is provided, wherein a weight made of a metal member adjacent to the piezoelectric element is formed when the piezoelectric element is laminated on the diaphragm by a semiconductor process. It can be grasped as an invention having a step of forming a material.

  According to the present invention, it is possible to provide a method of manufacturing a liquid ejecting head and an actuator device for the liquid ejecting head that can withstand the stress concentration and hardly cause a failure by disposing a weight material in a portion where the stress is easily concentrated. .

FIG. 2 is an exploded perspective view of a recording head according to an embodiment of the invention. FIG. 2 is a plan view of the recording head. FIG. 3 is a cross-sectional view of the same recording head. FIG. 6 is a cross-sectional view showing the manufacturing process of the recording head. FIG. 6 is a cross-sectional view showing the manufacturing process of the recording head. FIG. 6 is a cross-sectional view showing the manufacturing process of the recording head. FIG. 6 is a cross-sectional view showing the manufacturing process of the recording head. FIG. 2 is an enlarged plan view of a main part of the recording head. FIG. 2 is an enlarged cross-sectional view of a main part of the recording head. FIG. 6 is an enlarged plan view of a main part of the recording head according to a modified example. FIG. 2 is an enlarged cross-sectional view of a main part of the recording head. FIG. 6 is an enlarged plan view of a main part of the recording head according to a modified example. 1 is a schematic diagram illustrating an example of an ink jet recording apparatus.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing an ink jet recording head as an example of a liquid jet head according to Embodiment 1 of the present invention, FIG. 2 is a plan view, and FIG. 3 is a view taken along the line AA ′ shown in FIG. It is sectional drawing.
As shown in the drawing, the flow path forming substrate 10 is made of a silicon single crystal substrate in the present embodiment, and an elastic film 50 made of silicon dioxide is formed on one surface thereof.

  The flow path forming substrate 10 includes a row in which pressure generation chambers 12 partitioned by a plurality of wall portions 11 are arranged in parallel in the width direction (short direction) by anisotropic etching from the other surface side. Two rows are provided in the longitudinal direction of the pressure generating chamber 12. In addition, an ink supply path which is an example of a liquid supply path constituting an individual flow path for each nozzle opening, which will be described in detail later, together with the pressure generation chamber 12 on one end side in the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10. 14 and the communication path 13 are partitioned by the wall 11. The ink supply path 14 and the communication path 13 are arranged outside the two rows of the pressure generation chambers 12 in each row of the pressure generation chambers 12.

  The ink supply path 14 generates a flow path resistance for the ink between the manifold 100 and the pressure generation chamber 12 which will be described in detail. The ink supply path 14 communicates with one end in the longitudinal direction of the pressure generation chamber 12 and is a pressure generation chamber. Having a cross-sectional area of less than 12. For example, in the present embodiment, the ink supply path 14 is formed with a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path of the pressure generation chamber 12 in the width direction. As described above, in this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. Further, each communication path 13 communicates with the side of the ink supply path 14 opposite to the pressure generation chamber 12 and has a larger cross-sectional area than the width direction (short direction) of the ink supply path 14. In the present embodiment, the communication passage 13 is formed with the same cross-sectional area as the pressure generation chamber 12.

  In other words, the flow path forming substrate 10 is connected to the pressure generation chamber 12, the ink supply path 14 having a smaller cross-sectional area in the short direction of the pressure generation chamber 12, the ink supply path 14, and the ink supply. Two rows are provided in which the individual flow paths including the communication passage 13 having a cross-sectional area larger than the cross-sectional area in the short direction of the path 14 are partitioned by the plurality of wall portions 11.

  On the surface side of the flow path forming substrate 10 where the individual flow paths such as the pressure generation chambers 12 are opened, nozzle openings 21 communicating with the vicinity of the ends of the pressure generation chambers 12 opposite to the ink supply paths 14 are formed. In one example of the nozzle forming member, the nozzle plate 20 is fixed by an adhesive, a heat welding film, or the like. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.

  On the other hand, the elastic film 50 is formed on the surface of the flow path forming substrate 10 opposite to the nozzle plate 20, as described above, and the insulator film 55 is formed on the elastic film 50. ing. Further, a first electrode (bottom electrode) 60, a piezoelectric layer 70, and a second electrode (top electrode) 80 are laminated on the insulator film 55 by a process described later to constitute the piezoelectric element 300. is doing. Here, the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In the present embodiment, the first electrode 60 is a common electrode of the piezoelectric element 300, and the second electrode 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. That is, in this embodiment, the piezoelectric element 300 is provided as an actuator device that causes a pressure change in the ink (liquid) in the pressure generation chamber 12.

  The second electrode 80 of each piezoelectric element 300 has a lead electrode 90 such as gold (Au) extending to the vicinity of the end of the flow path forming substrate 10 opposite to the ink supply path 14. Each is connected. A voltage is selectively applied to each piezoelectric element 300 via the lead electrode 90. That is, in the present embodiment, the end portion of the lead electrode 90 opposite to the piezoelectric element 300 is a mounting portion to which a wiring board, which will be described in detail later, is electrically connected. In addition, when the lead electrode 90 is formed, a dummy lead electrode 91 that does not form an actual circuit is formed. The dummy lead electrode 91 will be described later.

  Further, on the flow path forming substrate 10 on which the piezoelectric element 300 is formed, the protective substrate 30 having the piezoelectric element holding portion 31 having a space that does not hinder the movement of the piezoelectric element 300 in a region facing the piezoelectric element 300. Are joined by an adhesive 35 or the like. Since the piezoelectric element 300 is disposed in the piezoelectric element holding portion 31, it is protected in a state where it is hardly affected by the external environment. In addition, the piezoelectric element holding part 31 may be sealed or may not be sealed. Further, the piezoelectric element holding portion 31 may be provided independently for each piezoelectric element 300 or may be provided continuously over a plurality of piezoelectric elements 300. In the present embodiment, the piezoelectric element holding portion 31 is continuously provided across the plurality of piezoelectric elements 300.

  Further, a manifold 100 serving as a common ink chamber (liquid chamber) for a plurality of individual flow paths is provided in a region facing the piezoelectric element holding portion 31 on the protective substrate 30. In the present embodiment, the manifold 100 is formed by a recess provided on the surface of the protective substrate 30 opposite to the joint surface with the flow path forming substrate 10. That is, the protective substrate 30 is opened on the side opposite to the flow path forming substrate 10, and the opening of the manifold 100 is sealed by a compliance substrate 40, which will be described in detail later. In addition, the manifold 100 is provided continuously over the short direction (width direction) of a plurality of individual flow paths. The manifold 100 is provided to the vicinity of both end portions of the protective substrate 30 in the longitudinal direction of the pressure generating chamber 12, and one end portion side of the manifold 100 is provided to a region facing the end portion of the individual flow path. Yes. Thus, by providing the manifold 100 above the piezoelectric element holding portion 31 (a region overlapping the piezoelectric element holding portion 31 when viewed in plan), it is necessary to widen the manifold 100 to the outside in the longitudinal direction of the pressure generating chamber 12. Therefore, the width in the longitudinal direction of the pressure generating chamber 12 of the ink jet recording head I can be reduced to reduce the size.

  In addition, the protective substrate 30 has one end communicating with the end portion of the communication path 13 that is an individual flow path, and the supply portion 101 that is a through hole penetrating in the thickness direction with the other end communicating with one end portion of the manifold 100. Is provided. In the present embodiment, one supply unit 101 is provided across the communication path 13 which is a plurality of individual flow paths. Then, the ink from the manifold 100 is supplied to the communication path 13, the ink supply path 14, and the pressure generation chamber 12, which are individual flow paths, via the supply unit 101. That is, in the present embodiment, the supply unit 101 also functions as a part of the manifold 100.

Examples of the material of the protective substrate 30 include glass, ceramic material, metal, resin, and the like, but it is preferable that the protective substrate 30 is formed of a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10. In this embodiment, a silicon single crystal substrate that is the same material as the flow path forming substrate 10 is used.
Further, the protective substrate 30 is provided with a through hole 102 penetrating in the thickness direction in a region corresponding to the two rows of the pressure generating chambers 12. The wiring board 200 is inserted through the through hole 102 and electrically connects the wiring board 200 and the mounting portion of the actuator device. Here, in the present embodiment, the actuator device is the piezoelectric element 300, and the lead electrode 90 connected to the piezoelectric element 300 is provided at a position where the end portion is disposed in the through hole 102.

  Further, one through hole 102 is provided for each row of the piezoelectric elements 300. That is, in the present embodiment, the wiring substrate 200 is connected to each column of the piezoelectric elements 300, and there are two columns of the piezoelectric elements 300, so two through holes 102 are provided. A partition wall 103 that partitions the mounting portion (the end portion of the lead electrode 90) is provided between the adjacent through holes 102. A region where the mounting portion is disposed in the elastic film 50 serving as a vibration plate is collectively referred to as a wiring region.

  The wiring substrate 200 is electrically connected to the end portion exposed in the through hole 102 of the lead electrode 90. The wiring board 200 has flexibility in which a driving circuit 201 for driving the piezoelectric element 300 is mounted on a wiring (not shown). For example, a chip-on-film (COF), a tape carrier package (TCP), or the like. A flexible printed circuit board (FPC) can be used.

  The wiring substrate 200 and the lead electrode 90 which is the mounting portion of the actuator device can be electrically connected via an anisotropic conductive adhesive (ACP) 210 having an appropriate amount applied to the wiring region. The anisotropic conductive adhesive 210 electrically connects the wiring substrate 200 and the lead electrode 90 and also functions as an adhesive that fixes the wiring substrate 200 in the through hole 102.

A compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded to the surface of the protective substrate 30 where the manifold 100 is opened, and the opening of the manifold 100 is sealed by the compliance substrate 40.
The sealing film 41 is made of a material having low rigidity and flexibility, for example, a polyphenylene sulfide (PPS) film having a thickness of about several μm.

  The fixing plate 42 is made of a hard material such as a metal such as stainless steel (SUS) having a thickness of about several tens of μm. As shown in FIG. 2, the fixing plate 42 is provided around the manifold 100 of the protective substrate 30, and a region facing the manifold 100 is an opening 43 that is completely removed in the thickness direction. ing. Further, the fixed plate 42 is provided with a protruding portion 44 that protrudes toward the opening 43 side, and this protruding portion 44 is provided from a storage means (not shown) that penetrates in the thickness direction and stores ink. An introduction path 45 is provided for supplying the ink to the manifold. In the present embodiment, the projecting portion 44 is provided on the side opposite to the supply portion 101 and so as to project a part of the pressure generating chamber 12 in the juxtaposed direction to a region facing the manifold 100. For this reason, the introduction path 45 is provided at the opposite end in the longitudinal direction of the pressure generating chamber 12 from the supply part 101 provided in the protective substrate 30. As described above, by providing the introduction path 45 at the end of the protective substrate 30 opposite to the supply unit 101, the influence of the dynamic pressure of the ink introduced from the storage unit is affected by the pressure generation chamber 12 via the supply unit 101. Can be reduced.

  And, by such an opening 43 of the fixing plate 42, one surface of the manifold 100 is a flexible part 46 that can be flexibly deformed and is sealed only by the flexible sealing film 41. In other words, in the present embodiment, the flexible portion 46 includes the introduction path 45 of the region facing the supply unit 101 of the protective substrate 30 in the region facing the manifold 100 and the fixing plate 42 in the region facing the manifold 100. The flexible portion 46 is continuously provided over the region opposite to the supply portion 101 and the periphery of the introduction path 45. Thus, by providing the flexible portion 46 continuously over the region facing the supply portion 101 and the periphery of the introduction path 45, the flexible portion 46 can be formed in a wide area, and the manifold 100. By increasing the internal compliance, it is possible to reliably reduce the occurrence of crosstalk due to the adverse effects of pressure fluctuations.

  In the present embodiment, since the wiring board 200 on which the driving circuit 201 is mounted is connected to the lead electrode 90, it is not necessary to mount the driving circuit 201 on the protective substrate 30. Therefore, the manifold 100 can be widened above the piezoelectric element holding portion 31, and the compliance substrate 40 having the wide flexible portion 46 can be provided on the protective substrate 30.

  In such an ink jet recording head according to the present embodiment, ink is taken into the manifold 100 from a storage unit that stores external ink (not shown), and the inside of the manifold 100 reaches the nozzle opening 21 via the supply unit 101. After filling with ink, a voltage is applied between each of the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12 in accordance with a recording signal from the drive circuit 201 to bend the piezoelectric element 300 and the diaphragm. By deforming, the pressure in each pressure generating chamber 12 increases and ink is ejected from the nozzle openings 21.

Next, a process of manufacturing the piezoelectric element 300 and the like by a semiconductor process will be described. 4 to 7 show cross-sectional views of each process.
As shown in FIG. 4, an oxide film 51 constituting an elastic film 50 is formed on the surface of a wafer 110 for flow path forming substrate which is a silicon wafer and in which a plurality of flow path forming substrates 10 are integrally formed.
Then, as shown in FIG. 5, an insulator film 55 made of an oxide film made of a material different from that of the elastic film 50 is formed on the elastic film 50 (oxide film 51).

Next, as shown in FIG. 6, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are sequentially stacked and patterned into a predetermined shape to form the piezoelectric element 300. Thereafter, although not shown, a coating layer made of an insulator is formed over the entire surface, and then an opening for connecting the first electrode 60 and the second electrode 80 is formed.
Next, as shown in FIG. 7, after the lead electrode 90 and the dummy lead electrode 91 made of, for example, gold (Au) are formed as metal members over the entire surface of the flow path forming substrate wafer 110, for example, Then, patterning is performed for each piezoelectric element 300 through a mask pattern (not shown) made of a resist or the like. As described above, since the opening for connecting the first electrode 60 and the second electrode 80 is formed in the coating layer made of an insulator, the lead electrode 90 is electrically connected to the second electrode 80 through the opening. is doing. The first electrode 60 is also conducted in a predetermined pattern.

  Next, the protective substrate wafer 130 is bonded to the flow path forming substrate wafer 110 by the adhesive 35. Here, a piezoelectric element holding portion 31, a manifold 100, a supply portion 101, a through hole 102, a partition wall 103, and the like are formed in advance on the protective substrate wafer 130. Since the protective substrate wafer 130 is relatively thick, the rigidity of the flow path forming substrate wafer 110 is remarkably improved by bonding the protective substrate wafer 130. Thereafter, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

Next, a mask film 52 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, by performing anisotropic etching (wet etching) using an alkaline solution such as KOH on the flow path forming substrate wafer 110 through the mask film 52, the pressure generating chamber 12, the communication path 13, the ink supply path 14, and the like. Form.
When forming the individual flow path on the flow path forming substrate wafer 110, the surface of the protective substrate wafer 130 opposite to the flow path forming substrate wafer 110 side is made of a material having alkali resistance, for example, It is preferable to seal with a sealing film made of PPS (polyphenylene sulfide), PPTA (polyparaphenylene terephthalamide) or the like. In this embodiment, the manifold 100 and the supply unit 101 are provided in advance on the protective substrate wafer 130. However, the present invention is not limited to this. For example, the flow path forming substrate wafer 110, the protective substrate wafer 130, When the flow path forming substrate wafer 110 is wet-etched to form the pressure generation chamber 12 and the like after the bonding, the manifold 100 and the supply unit 101 may be simultaneously formed by wet etching. Thereby, the manufacturing process can be simplified and the cost can be reduced.

  Next, after the compliance substrate 40 is bonded to the protective substrate wafer 130, the wiring substrate 200 (wiring not shown) is electrically connected to the lead electrodes 90 in one row of the piezoelectric elements 300 exposed in the one through hole 102. Connecting. The wiring substrate 200 and the lead electrode 90 are joined via an anisotropic conductive adhesive 210. Specifically, after filling the through hole 102 with the anisotropic conductive adhesive 210, the wiring substrate 200 is heated while being pressed onto the lead electrode 90, thereby connecting the lead electrode 90 and the wiring substrate 200. To do. Incidentally, in order to heat the wiring board 200 while pressing it onto the lead electrode 90, a mounting tool that contacts the back surface of the wiring board 200 is used. Note that the formation position of the dummy lead electrode 91 and the formation position of the lead electrode 90 are deviated, and the tip portion of the wiring substrate 200 is connected to the lead electrode 90 but not connected to the dummy lead electrode 91.

  In the process before or after connecting the wiring substrate 200, unnecessary portions of the outer peripheral edge portions of the flow path forming substrate wafer 110 and the protective substrate wafer 130 are removed by cutting, for example, by dicing. The nozzle plate 20 in which the nozzle openings 21 are formed is bonded to the surface of the flow path forming substrate wafer 110 opposite to the protective substrate wafer 130. Then, the flow path forming substrate wafer 110 and the like are divided into a single chip size flow path forming substrate 10 and the like as shown in FIG. 1, whereby the ink jet recording head I of this embodiment is manufactured. Of course, the compliance board 40 may be fixed after the wiring board 200 is connected.

FIG. 8 shows an enlarged plan view of the periphery of the piezoelectric element in the recording head I, and FIG. 9 shows a cross-sectional view taken along line AA.
As described above, the first electrode 60 is a common electrode, and a plurality of piezoelectric layers 70 are formed in parallel at a predetermined interval so as to be perpendicular to the first electrode 60. At this time, since the piezoelectric layer 70 is formed longer than the width of the first electrode 60, a portion on the first electrode 60 and a portion not on the first electrode 60 are generated. In this sense, the piezoelectric element 300 is formed so as to straddle a portion on the first electrode 60 (bottom electrode) and a portion where the first electrode 60 (bottom electrode) is interrupted. On the other hand, the second electrode 80 is formed by patterning so as to remain only at the top of the piezoelectric layer 70. That is, the second electrode 80 is formed as long as the length of the piezoelectric layer 70. The piezoelectric layer 70 and the second electrode 80 are formed in a trapezoidal shape in which the cross section becomes narrower as the distance from the first electrode 60 increases.

  The second electrode 80 is electrically connected to the lead electrode 90 through the above-described opening, and the first electrode 60 is also formed on another electrode portion in a predetermined pattern (not shown). When a predetermined drive signal is applied between the first electrode 60 and the lead electrode 90 and an electric field is formed between the first electrode 60 and the second electrode 80, the piezoelectric layer 70 therebetween. Is displaced. The piezoelectric layer 70 has a portion that is in contact with the first electrode 60 and a portion that is not in contact with it. When a drive signal is applied, the portion that is in contact with the first electrode 60 tends to be displaced, and the portion that is not in contact is not displaced. That is, stress concentrates on the piezoelectric layer 70 at this boundary.

  Here, the lead electrode 90 extends from the position not overlapping the first electrode 60 above the piezoelectric element 300 toward the wiring region described above. On the other hand, the dummy lead electrode 91 extends from a position not covering the same wiring region to between the adjacent piezoelectric elements 300 and 300 to a position overlapping the first electrode 60. That is, each formation position has shifted | deviated. Further, since the dummy lead electrode 91 is formed slightly wider at the position intersecting with the first electrode 60, it has a deformed cross shape. Let this cross-shaped site | part be the wide site | part 91a.

  The dummy lead electrode 91 is formed of gold (Au) in the same manner as the lead electrode 90. Gold is a metal and the largest element. The dummy lead electrode 91 and the wide portion 91 a are formed side by side with the piezoelectric element 300. That is, it functions as a weight material, and is formed so as to straddle a portion on the first electrode 60 (bottom electrode) and a portion where the first electrode 60 (bottom electrode) is disconnected in the piezoelectric elements 300 adjacent to each other. It has been done.

  In the piezoelectric layer 70, stress concentrates on the above-described portion, and a weight material composed of the dummy lead electrode 91 and the wide portion 91a is formed in the stress concentration portion. Therefore, the stress based on the displacement is not concentrated only on the piezoelectric layer 70 due to the effect of the mass of the weight material at this portion, but is dispersed by the dummy lead electrode 91 and the wide portion 91a. By being dispersed, a failure such as a crack is less likely to occur in the piezoelectric pair element 300.

FIG. 10 is an enlarged plan view of a main part of a recording head I according to a modification, and FIG. 11 is an enlarged cross-sectional view.
In this modification, the wide portion 91a is further widened with respect to the dummy lead electrode 91 to form the wide portion 91b. As described above, the piezoelectric element 300 has a trapezoidal cross section. In this modification, the wide portion 91b is formed so as to cover the side wall portion of the inclined surface that is trapezoidal so that the wide portion 91b connects between the adjacent piezoelectric elements 300 and 300.

When formed in this way, the weight material is not limited to the effect that it is formed at the stress concentration site, but also acts to more positively press and fix the stress concentration site. As a result, the weight material tries to fix the entire boundary between the part to be displaced and the part that does not change, so that the stress is not concentrated in one place but is easily dispersed.
Further, FIG. 12 is an enlarged plan view of a main part of the recording head according to the modification.

  In this modification, a wide portion 91 c whose width gradually changes with respect to the dummy lead electrode 91 is formed. That is, the wide portion 91c is the widest at the end portion on the side to be displaced in contact with the first electrode 60, and extends to a position covering the side wall having the inclined surface described above. However, the width gradually decreases toward the side that is not in contact with the first electrode 60 and is not displaced, and finally has a shape that matches the width of the dummy lead electrode 91. That is, the weight material is formed wide on the first electrode 60 (bottom electrode) and gradually becomes narrower toward the side where the first electrode 60 (bottom electrode) is cut off.

When formed in this way, the action of trying to fix the portion of the piezoelectric element 300 to be displaced more positively and gradually to the side of the portion not displaced is reduced. That is, it can be said that the shape is such that a large fixing force is generated at a necessary portion and a large fixing force is not generated at an unnecessary portion, so that it is an efficient shape.
In addition, the ink jet recording heads of these embodiments constitute a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and are mounted on the ink jet recording apparatus. FIG. 13 is a schematic view showing an example of the ink jet recording apparatus.

  As shown in FIG. 13, the ink jet recording apparatus II includes recording head units 1A and 1B each having an ink jet recording head. The recording head units 1A and 1B include cartridges 2A and 2B constituting ink supply means. A carriage 3 that is detachably mounted and on which the recording head units 1A and 1B are mounted is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.

  Furthermore, the present invention is intended for a wide range of liquid jet heads in general, for example, for manufacturing recording heads such as various ink jet recording heads used in image recording apparatuses such as printers, and color filters such as liquid crystal displays. The present invention can also be applied to a coloring material ejecting head, an organic EL display, an electrode material ejecting head used for forming an electrode such as an FED (field emission display), a bioorganic matter ejecting head used for biochip production, and the like.

Further, although the ink jet recording apparatus II has been described as an example of the liquid ejecting apparatus, the liquid ejecting apparatus using the other liquid ejecting heads described above can also be used.
Needless to say, the present invention is not limited to the above embodiments. It goes without saying for those skilled in the art,
・ Apply by changing the combination of the mutually replaceable members and configurations disclosed in the above embodiments as appropriate.

・ Although not disclosed in the above-described embodiments, members and configurations that are known techniques and can be mutually replaced with the members and configurations disclosed in the above-described embodiments are appropriately replaced, and combinations thereof are changed. Although not disclosed in the above embodiments, members and configurations that can be assumed by those skilled in the art as substitutes for the members and configurations disclosed in the above embodiments based on known techniques Replace as appropriate, change the combination and apply

Is disclosed as an embodiment of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Flow path formation board | substrate, 12 ... Pressure generation chamber, 13 ... Communication path, 14 ... Ink supply path, 20 ... Nozzle plate, 21 ... Nozzle opening, 30 ... Protection board | substrate, 40 ... Compliance board | substrate, 41 ... Sealing film, 42 ... fixing plate, 43 ... opening, 46 ... flexible part, 50 ... elastic film, 55 ... insulator film, 60 ... first electrode (bottom electrode), 70 ... piezoelectric layer, 80 ... second electrode (top) Electrode), 90 ... Lead electrode (mounting part), 91 ... Dummy lead electrode, 91a, 91b, 91c ... Wide part, 100 ... Manifold, 101 ... Supply part, 102 ... Through-hole, 103, 103A ... Bulkhead, 200 ... Wiring Substrate, 201... Drive circuit, 210... Anisotropic conductive adhesive, 300... Piezoelectric element (actuator device).

Claims (6)

A flow path forming substrate in which predetermined flow paths corresponding to a plurality of nozzles are formed is sandwiched between the nozzle plate in which the nozzle is formed and the vibration plate, and each surface of the vibration plate opposite to the flow path forming substrate is placed on each surface. A liquid ejecting head in which a piezoelectric element is disposed corresponding to a flow path,
A liquid ejecting head, wherein a weight member made of a metal member adjacent to the piezoelectric element is formed when the piezoelectric element is laminated on the diaphragm by a semiconductor process.   In the piezoelectric element, when a bottom electrode as a common electrode is formed on the diaphragm side and a top electrode as an individual electrode is formed on the opposite side, a plurality of the piezoelectric elements are formed with respect to the bottom electrode as a common electrode. The piezoelectric element is formed, and the weight material is formed so as to straddle a portion of the piezoelectric element adjacent to each other on the bottom electrode and a portion where the bottom electrode is cut off. The liquid ejecting head according to 1.   On the bottom electrode formed as a common electrode in a predetermined range, a plurality of the piezoelectric elements are formed at predetermined intervals so as to intersect the bottom electrode, and the weight material is provided between the adjacent piezoelectric elements. The liquid ejecting head according to claim 2, wherein the liquid ejecting head is formed in common.   Each piezoelectric element is formed so as to have a trapezoidal cross section in which the upper surface is narrowed away from the diaphragm, and when the side wall portion is inclined, the weight material is formed so as to cover the side wall portion. The liquid ejecting head according to claim 3, wherein the liquid ejecting head is provided.   5. The liquid jet according to claim 2, wherein the weight material is formed wide on the bottom electrode and gradually becomes narrower toward a side where the bottom electrode is cut off. 6. head. A manufacturing method of an actuator device in which a piezoelectric element that generates pressure in a flow path forming substrate on which a predetermined flow path portion is formed in a liquid ejecting head is provided,
A method of manufacturing an actuator device for a liquid jet head, comprising: forming a weight member made of a metal member adjacent to the piezoelectric element when the piezoelectric element is laminated on the diaphragm by a semiconductor process.

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