JP2014197576A - Liquid injection head, liquid injection apparatus, piezo electric element, ultrasonic transducer and ultrasonic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection head, a liquid injection apparatus, a piezo electric element, an ultrasonic transducer and an ultrasonic device which can protect a piezo electric element, suppress occurrence of disconnection of wiring or generation of foreign matters, and enable high-density wiring.SOLUTION: A liquid injection head comprises a channel-formed board 10 equipped with a pressure generation chamber 12 intercommunicating with a nozzle opening for injecting liquid, and a piezo electric element 300 which is disposed on one surface side of the channel-formed board 10 and has a first electrode 60, a piezo electric layer 70 and a second electrode 80. Plural active parts 310 which substantially serve as a driving part sandwiched between the first electrode 60 and the second electrode 80 are provided. The first electrode 60 is an individual electrode which is provided for each one of the active parts 310, the second electrode 80 is a common electrode provided across the plural active parts 310. The piezo electric layer 70 is provided across the plural active parts 310, and the piezo electric layer 70 is provided with recess portions 71 among the plural active parts 31. The second electrode 80 is not formed at least on a side surface of the recess portion 71.

Description

  The present invention relates to a liquid ejecting head that ejects liquid from a nozzle opening, a liquid ejecting apparatus, a piezoelectric element, an ultrasonic transducer, and an ultrasonic device.

  A liquid ejecting head that ejects liquid droplets from a nozzle opening communicating with a pressure generating chamber by deforming a piezoelectric element (piezoelectric actuator) to cause a pressure fluctuation in the liquid in the pressure generating chamber is known. A typical example of the liquid ejecting head is an ink jet recording head that ejects ink droplets as droplets.

  An ink jet recording head includes, for example, a piezoelectric element on one side of a flow path forming substrate provided with a pressure generating chamber communicating with a nozzle opening, and deforms a diaphragm by driving the piezoelectric element, thereby The ink is caused to change in pressure, and ink droplets are ejected from the nozzle openings.

  Here, the piezoelectric element includes a first electrode, a piezoelectric layer, and a second electrode provided on the diaphragm, and the first electrode and the second electrode are connected to a wiring connected to a driving IC or the like. For example, Japanese Patent Application Laid-Open No. H10-228707 discloses a wiring layer connected to the wiring layer.

JP 2011-110784 A

However, when the side surface shape of the concave portion provided in the piezoelectric layer that separates the active portion that is the substantial driving portion of the piezoelectric element is steep, that is, formed at an angle close to perpendicular to the surface of the flow path forming substrate In addition, there is a problem that when the unevenness (roughness) of the side surface is large, the second electrode may not be well formed on the side surface and may be disconnected or peeled off to become a foreign matter.
In particular, when the concave portion of the piezoelectric layer is formed by wet etching, the roughness becomes large, and the attachment around the second electrode is liable to occur.

Further, when the side surface is formed at an angle close to the surface of the flow path forming substrate, there is a problem that the piezoelectric elements (active portions) cannot be arranged with high density.
In addition, if the thickness of the second electrode is reduced in order to improve the displacement characteristics of the piezoelectric element, a contact defect in the side surface of the recess is particularly likely to occur.

  In view of such circumstances, the present invention can protect a piezoelectric element, suppress disconnection of wiring and generation of foreign matter, and can be disposed at a high density, a liquid ejecting head, a liquid ejecting apparatus, a piezoelectric element, a super It is an object to provide an acoustic transducer and an ultrasonic device.

An aspect of the present invention that solves the above problems includes a flow path forming substrate provided with a pressure generating chamber communicating with a nozzle opening for ejecting liquid, and a first electrode provided on one side of the flow path forming substrate. A liquid ejecting head including a piezoelectric layer and a piezoelectric element having a second electrode, and a plurality of active parts serving as a substantial driving part sandwiched between the first electrode and the second electrode. The first electrode is an individual electrode provided for each active part, the second electrode is a common electrode provided across the plurality of active parts, and the piezoelectric layer includes a plurality of active parts. The piezoelectric layer is provided with a recess between the plurality of active portions, and the second electrode is not formed on at least the side surface of the recess. The liquid jet head is characterized by the following.
In such an aspect, by preventing the second electrode from being formed on the side surface of the concave portion of the piezoelectric layer, disconnection or peeling due to poor formation of the second electrode in the concave portion can be suppressed.

  Here, it is preferable that a protective film made of an insulating material is formed on at least the side surface of the recess. According to this, by forming the protective film on the side surface of the recess, it is possible to suppress the destruction of the piezoelectric layer due to the external environment.

  The protective film is preferably formed of a material having a Young's modulus smaller than that of the second electrode. According to this, it can suppress that a protective film inhibits the displacement of an active part, and can improve the piezoelectric characteristic of an active part.

  The protective film preferably has a tensile stress as an internal stress. According to this, the active part can be deformed so as to be convex on the side opposite to the flow path forming substrate, and the amount of displacement of the active part can be improved.

  Moreover, it is preferable to have a wiring layer provided continuously over the plurality of active portions in a region other than the concave portion on the second electrode. According to this, even if the electrical resistance value is increased by dividing the second electrode by the concave portion, one or a few active parts are driven alone or simultaneously, and a large number of active parts are driven simultaneously. Thus, it is possible to suppress a voltage drop from occurring when a large number of droplets are discharged at a time, and to suppress a drop and variation in droplet discharge characteristics.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to the above aspect.
In this aspect, it is possible to realize a liquid ejecting apparatus that improves reliability by suppressing breakage and peeling of the second electrode and suppressing breakage of the piezoelectric layer.

According to another aspect of the present invention, there is provided a piezoelectric element having a first electrode, a piezoelectric layer, and a second electrode, which is a substantial driving unit sandwiched between the first electrode and the second electrode. A plurality of active portions, wherein the first electrode is an individual electrode provided for each active portion, the second electrode is a common electrode provided across the plurality of active portions, and the piezoelectric layer Is provided over a plurality of active portions, and the piezoelectric layer is provided with a recess between the plurality of active portions, and the second electrode is provided on at least a side surface of the recess. The piezoelectric element is characterized in that a protective film made of an insulating material is formed without being formed.
In such an aspect, by preventing the second electrode from being formed on the side surface of the concave portion of the piezoelectric layer, disconnection or peeling due to poor formation of the second electrode in the concave portion can be suppressed. In addition, by forming a protective film on the side surface of the recess, it is possible to suppress destruction of the piezoelectric layer due to the external environment.

Furthermore, another aspect of the present invention is an ultrasonic transducer including the piezoelectric element according to the above aspect.
In such an aspect, by preventing the second electrode from being formed on the side surface of the concave portion of the piezoelectric layer, disconnection or peeling due to poor formation of the second electrode in the concave portion can be suppressed. Accordingly, the side surface of the active portion is steep and high density arrangement is possible.

According to another aspect of the present invention, there is provided an ultrasonic device comprising: a substrate having an opening; and the ultrasonic transducer according to the above aspect provided on the substrate.
In this aspect, it is possible to realize an ultrasonic device that has improved reliability by suppressing breakage and peeling of the second electrode and suppressing breakage of the piezoelectric layer.

FIG. 2 is an exploded perspective view of a recording head according to Embodiment 1 of the invention. FIG. 3 is a plan view of a flow path forming substrate of the recording head according to the first embodiment of the invention. 2A and 2B are a cross-sectional view and an enlarged cross-sectional view of a recording head according to Embodiment 1 of the invention. FIG. 2 is an enlarged cross-sectional view of a main part of the recording head according to Embodiment 1 of the invention. FIG. 2 is an enlarged cross-sectional view of a main part of the recording head according to Embodiment 1 of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. FIG. 5 is a cross-sectional view illustrating the method for manufacturing the recording head according to the first embodiment of the invention. It is the schematic which shows the liquid ejecting apparatus which concerns on Embodiment 1 of this invention. It is the top view and sectional view of an ultrasonic device concerning Embodiment 2 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a perspective view of an ink jet recording head that is an example of a liquid jet head according to Embodiment 1 of the present invention, FIG. 2 is a plan view of a flow path forming substrate of the ink jet recording head, and FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 2, FIG. 4 is a cross-sectional view taken along the line BB ′ of FIG. 2, and FIG. 5 is a cross-sectional view taken along the line CC ′ of FIG.

  As shown in the drawing, a pressure generating chamber 12 is formed in a flow path forming substrate 10 provided in an ink jet recording head I which is an example of a liquid ejecting head of the present embodiment. The pressure generating chambers 12 partitioned by the plurality of partition walls 11 are arranged side by side along the direction in which the plurality of nozzle openings 21 for discharging ink are arranged in parallel. Hereinafter, this direction is referred to as a direction in which the pressure generating chambers 12 are arranged side by side or a first direction X. Further, the direction orthogonal to the first direction X is hereinafter referred to as a second direction Y.

  An ink supply path 13 and a communication path 14 are provided on one end side in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate 10, that is, on one end side in the second direction Y orthogonal to the first direction X. Is partitioned by a plurality of partition walls 11. On the outside of the communication passage 14 (on the side opposite to the pressure generation chamber 12 in the second direction Y), a communication portion that constitutes a part of the manifold 100 serving as a common ink chamber (liquid chamber) of each pressure generation chamber 12. 15 is formed. That is, the flow path forming substrate 10 is provided with a liquid flow path including a pressure generation chamber 12, an ink supply path 13, a communication path 14, and a communication portion 15.

  On one side of the flow path forming substrate 10, that is, the surface where the liquid flow path such as the pressure generation chamber 12 opens, a nozzle plate 20 having a nozzle opening 21 communicating with each pressure generation chamber 12 is provided with an adhesive. Or a heat-welded film or the like. In other words, the nozzle openings 21 are arranged in the nozzle plate 20 in the first direction X.

  A diaphragm 50 is formed on the other surface side of the flow path forming substrate 10. The diaphragm 50 according to the present embodiment includes an elastic film 51 formed on the flow path forming substrate 10 and an insulator film 52 formed on the elastic film 51. The liquid flow path such as the pressure generation chamber 12 is formed by anisotropically etching the flow path forming substrate 10 from one surface, and the other surface of the liquid flow path such as the pressure generation chamber 12 is a diaphragm. 50 (elastic film 51).

  On the insulator film 52, the piezoelectric element 300 including the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is formed. The piezoelectric element 300 provided on the substrate (the flow path forming substrate 10) is the actuator device of the present embodiment.

Hereinafter, the piezoelectric element 300 constituting the actuator device will be described in more detail with reference to FIGS. 3 and 4.
As shown in the figure, the first electrode 60 constituting the piezoelectric element 300 is separated for each pressure generation chamber 12 and constitutes an independent electrode for each active part which is a substantial driving part of the piezoelectric element 300 described later. To do. The first electrode 60 is formed with a width narrower than the width of the pressure generation chamber 12 in the first direction X of the pressure generation chamber. That is, in the first direction X of the pressure generation chamber 12, the end portion of the first electrode 60 is located inside the region facing the pressure generation chamber 12. In the second direction Y, both end portions of the first electrode 60 are extended to the outside of the pressure generation chamber 12. The material of the first electrode 60 is not particularly limited as long as it is a conductive material. For example, a noble metal such as platinum (Pt) or iridium (Ir) is preferably used.

  The piezoelectric layer 70 is continuously provided in the first direction X so that the second direction Y has a predetermined width. The width of the piezoelectric layer 70 in the second direction Y is wider than the length of the pressure generation chamber 12 in the second direction Y. Therefore, in the second direction Y of the pressure generation chamber 12, the piezoelectric layer 70 is provided to the outside of the pressure generation chamber 12.

  In the second direction Y of the pressure generating chamber 12, the end of the piezoelectric layer 70 on the ink supply path 13 side is located outside the end of the first electrode 60. That is, the end portion of the first electrode 60 is covered with the piezoelectric layer 70. The end of the piezoelectric layer 70 on the nozzle opening 21 side is located on the inner side (pressure generation chamber 12 side) of the end of the first electrode 60, and the end of the first electrode 60 on the nozzle opening 21 side. The portion is not covered with the piezoelectric layer 70.

The piezoelectric layer 70 is made of a piezoelectric material of the oxide having a polarization structure formed on the first electrode 60, for example, may consist of a perovskite oxide represented by the general formula ABO _3, A is Pb B can contain at least one of zirconium and titanium. The B may further contain niobium, for example. Specifically, as the piezoelectric layer 70, for example, lead zirconate titanate (Pb (Zr, Ti) O3: PZT), lead zirconate titanate niobate containing silicon (Pb (Zr, Ti, Nb)) O3: PZTNS) or the like can be used.

  Further, the piezoelectric layer 70 is a lead-free piezoelectric material that does not contain lead, for example, a composite oxide having a perovskite structure containing bismuth ferrate or bismuth ferrate manganate, barium titanate or potassium bismuth titanate, or the like. It is good.

  As will be described in detail later, the piezoelectric layer 70 is a liquid phase method such as a sol-gel method or a MOD (Metal-Organic Decomposition) method, or a PVD (Physical Vapor Deposition) method such as a sputtering method or a laser ablation method. Phase method).

  In such a piezoelectric layer 70, recesses 71 corresponding to the respective partition walls 11 are formed. The width of the recess 71 in the first direction X is substantially the same as or wider than the width of each partition 11 in the first direction. As a result, the rigidity of the portion of the vibration plate 50 that opposes the end portion of the pressure generation chamber 12 in the second direction Y (the arm portion of the vibration plate 50) is suppressed, so that the piezoelectric element 300 can be favorably displaced. it can.

The second electrode 80 is provided on the opposite surface side of the piezoelectric layer 70 from the first electrode 60 and constitutes a common electrode common to the plurality of active portions 310.
Here, the second electrode 80 is not provided at least on the inner wall surface of the recess 71 of the piezoelectric layer 70. That is, the second electrode 80 is not provided on the side surface intersecting the surface of the flow path forming substrate 10 of the recess 71 of the piezoelectric layer 70.

  The second electrode 80 is continuously provided across the plurality of active portions 310 on both sides of the recess 71 in the second direction Y. That is, the second electrode 80 is not provided in the recess 71, but is provided continuously around the periphery of the recess 71 on the piezoelectric layer 70.

  Thus, by not forming the second electrode 80 on the side surface of the concave portion 71 of the piezoelectric layer 70, it is possible to suppress the second electrode 80 from being peeled off and becoming a foreign substance or from being disconnected. Accordingly, the side surface of the concave portion 71 of the piezoelectric layer 70 is steep, that is, formed at an angle close to perpendicular to the surface of the flow path forming substrate 10 (flow path forming substrate wafer 110), Unevenness (roughness) can be increased. For this reason, the side surfaces of the recesses 71 of the piezoelectric layer 70 can be steep, and the piezoelectric layer 70 can be arranged at a high density, and the patterning method of the piezoelectric layer 70 is not limited, and it is an efficient and low-cost method. It can be patterned.

  In addition, since the second electrode 80 is not formed on the side surface of the concave portion 71 of the piezoelectric layer 70, it is possible to suppress poor contact with the side surface of the second electrode 80. The displacement characteristics of the piezoelectric element 300 (active part 310) can be improved by making it relatively thin.

  In the present embodiment, the second electrode 80 extends from the first electrode 60 to the surface of the piezoelectric layer 70 opposite to the flow path forming substrate 10 through the side surface of the piezoelectric layer 70. Yes. Then, the second electrode 80 continuous from the top of the first electrode 60 and the second electrode 80 provided in the main part (active part 310) of the piezoelectric layer 70 are electrically disconnected via the removing part 83. ing. That is, the second electrode 80 extended from the first electrode 60 onto the piezoelectric layer 70 and the second electrode 80 provided in the active part 310 are made of the same layer but are electrically discontinuous. It is formed as follows. Here, the removing portion 83 is provided on the nozzle opening 21 side on the piezoelectric layer 70 (on the side opposite to the flow path forming substrate 10), and the second electrode 80 is disposed in the thickness direction (flow path forming substrate 10). And the piezoelectric element 300 in the stacking direction) and electrically cut. Such a removal part 83 is provided so that the 2nd electrodes 80 on the adjacent 1st electrode 60 may become electrically independent by providing continuously in the 1st direction X. As shown in FIG.

  As the second electrode 80, a conductive material, for example, a metal material such as iridium (Ir), platinum (Pt), palladium (Pd), or gold (Au), a metal oxide, or the like is used. it can. Of course, the second electrode 80 may be a single material of the above metal material, a plurality of materials in which a plurality of materials are mixed, or a single layer or a plurality of layers in which two or more layers are laminated. May be.

  Such a piezoelectric element 300 including the first electrode 60, the piezoelectric layer 70, and the second electrode 80 is displaced by applying a voltage between the first electrode 60 and the second electrode 80. That is, by applying a voltage between both electrodes, a piezoelectric strain is generated in the piezoelectric layer 70 sandwiched between the first electrode 60 and the second electrode 80. A portion where piezoelectric distortion occurs in the piezoelectric layer 70 when a voltage is applied to both electrodes, that is, a region sandwiched between the first electrode 60 and the second electrode 80 is referred to as an active portion 310. On the other hand, a portion where no piezoelectric distortion occurs in the piezoelectric layer 70 is referred to as an inactive portion. Further, in the active part 310 in which piezoelectric distortion occurs in the piezoelectric layer 70, a part facing the pressure generation chamber 12 is referred to as a flexible part, and a part outside the pressure generation chamber 12 is referred to as a non-flexible part.

In the present embodiment, all of the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are continuously provided to the outside of the pressure generation chamber 12 in the second direction Y. That is, the active part 310 is continuously provided to the outside of the pressure generation chamber 12. Therefore, a portion of the active portion 310 that faces the pressure generation chamber 12 of the piezoelectric element 300 is a flexible portion, and a portion outside the pressure generation chamber 12 is a non-flexible portion.
That is, in this embodiment, as shown in FIG. 3, the end portion in the second direction Y of the active portion 310 is defined by the end portion of the second electrode 80 (including the end portion by the removal portion 83). .

  Further, the end of the active part 310 in the first direction X is defined by the first electrode 60. The end portion of the first electrode 60 in the first direction X is provided in a region facing the pressure generation chamber 12. Therefore, the end portion of the active portion 310 in the first direction X is provided in the flexible portion, and in the first direction X, the stress at the boundary between the active portion 310 and the inactive portion is caused by the diaphragm. Released by 50 deformations. For this reason, destruction such as burnout and cracks due to stress concentration at the end portion of the active portion 310 in the first direction X can be suppressed.

  In such a piezoelectric element 300, since the main part of the first electrode 60 is covered with the piezoelectric layer 70, current does not leak between the first electrode 60 and the second electrode 80, and the piezoelectric element 300. Can be prevented from breaking. Incidentally, if the first electrode 60 and the second electrode 80 are exposed in the proximity of each other, current leaks from the surface of the piezoelectric layer 70 and the piezoelectric layer 70 is destroyed. Even if the first electrode 60 and the second electrode 80 are exposed, current leakage does not occur unless the distance is short.

A protective film 200 made of an insulating material is provided on the side surface of the piezoelectric layer 70 in the recess 71 provided in the piezoelectric layer 70 of the piezoelectric element 300.
The material of the protective film 200 is made of an insulating material having moisture resistance. By covering the piezoelectric element 300 with the protective film 200 in this way, it is possible to prevent the piezoelectric element 300 from being destroyed due to moisture in the atmosphere. Here, the material of the protective film 200 may be a material having moisture resistance, and an inorganic insulating material, an organic insulating material, or the like can be used.

Examples of the inorganic insulating material that can be used as the protective film 200 include at least one selected from silicon oxide (SiOx), zirconium oxide (ZrOx), tantalum oxide (TaOx), aluminum oxide (AlOx), and titanium oxide (TiOx). Can be mentioned. As the inorganic insulating material of the protective film 200, it is particularly preferable to use inorganic amorphous material such as aluminum oxide (AlOx), for example, alumina (Al ₂ O ₃ ). The protective film 200 made of an inorganic insulating material can be formed by vapor phase film formation such as MOD method, sol-gel method, sputtering method, and CVD method, for example.

  On the other hand, examples of the organic insulating material that can be used as the protective film 200 include at least one selected from an epoxy resin, a polyimide resin, a silicon resin, and a fluorine resin. The protective film 200 made of an organic insulating material can be formed, for example, by liquid phase film formation that is a solution coating method such as a spin coating method or a spray method.

  The protective film 200 is preferably made of a material that can be formed on the side surface in the recess 71 of the piezoelectric layer 70 with better coverage than the second electrode 80. Accordingly, the coverage of the side surface of the piezoelectric layer 70 can be improved as compared with the case where the second electrode 80 is provided on the side surface in the concave portion 71 of the piezoelectric layer 70, and the protective film 200 is used to improve the coverage of the piezoelectric layer 70. It is possible to protect the piezoelectric layer 70 by reliably covering the side surface in the recess 71.

  The protective film 200 is preferably made of a material having a Young's modulus lower than that of the second electrode 80. Thereby, compared with the case where the 2nd electrode 80 is provided in the side surface (wall surface of the recessed part 71) of the piezoelectric material layer 70, by providing the protective film 200 whose Young's modulus is lower than the 2nd electrode 80, the piezoelectric element 300 ( The displacement characteristics of the active part) can be improved.

  Furthermore, the protective film 200 preferably has a tensile stress as an internal stress. In this way, by making the internal stress of the protective film 200 a tensile stress, the active portion 310 can be convex on the side opposite to the pressure generating chamber 12 and the displacement characteristics can be improved. Note that the tensile stress can be used as the internal stress of the protective film 200 by liquid phase film formation such as vapor phase film formation such as CVD method or solution coating method such as spin coating method.

  In this embodiment, the protective film 200 is provided so that polyimide is filled in the recess 71. In the present embodiment, the protective film 200 is formed so as to be filled only in the recess 71 by spin coating. The protective film 200 thus formed is formed into a curved surface whose surface (on the side opposite to the flow path forming substrate 10) is continuously concave on the surface of the second electrode 80.

  Note that the protective film 200 of this embodiment is not formed on the second electrode 80. This is because if the protective film 200 is provided on the active part 310, the active part 310 is restrained by the protective film 200 and the displacement characteristics of the active part 310 are deteriorated. Further, even in a region other than the active portion 310, if the protective film 200 is formed on the second electrode 80, it will be an obstacle when forming a wiring or the like to be described later on the second electrode 80 in detail. Contact holes are required. In the present embodiment, by providing the protective film 200 only in the recess 71, the piezoelectric layer 70 can be protected without inhibiting the displacement of the active part 310 and without forming a contact hole or the like. .

Further, the second electrode 80 is not formed on the protective film 200 provided in the recess 71. Incidentally, when the second electrode 80 is formed on the protective film 200, the displacement amount of the active portion 310 is reduced because the second electrode 80 has a large Young's modulus. In the present embodiment, it is possible to suppress a decrease in displacement of the active portion 310 by not providing the second electrode 80 or a wiring described later in detail on the protective film 200.
In addition, the recessed part 71 of this embodiment may be shorter than the 2nd direction Y of the pressure generation chamber 12, for example, and may be longer than the 2nd direction Y of the pressure generation chamber 12.

Here, the difference in size of the recess 71 is shown in FIG. 5 is a cross-sectional view taken along the line CC ′ of FIG. 2 showing the difference in size of the recesses.
As shown in FIG. 5A, the recess 71 is provided on the inner side of the end portion in the second direction Y of the pressure generation chamber 12. Accordingly, the piezoelectric element 300 is formed on the end portion of the pressure generation chamber 12 in the second direction Y, and the diaphragm on the end portion of the pressure generation chamber 12 in the second direction Y is formed. The destruction of 50 or the like can be suppressed.

Further, as shown in FIG. 5B, the recess 71 extends to the outside of the end portion of the pressure generation chamber 12 in the second direction Y. Thereby, the diaphragm 50 on the end portion of the pressure generation chamber 12 in the second direction Y is easily displaced, and the displacement characteristics of the active portion 310 are improved.
The length of the recess 71 in the second direction Y may be appropriately selected based on the characteristics of the diaphragm 50 and the piezoelectric element 300.

The lead electrode 90 (individual lead electrode 91 and common lead electrode 92), which is the wiring layer of the present embodiment, is connected to the first electrode 60 and the second electrode 80 of the piezoelectric element 300.
In this embodiment, the individual lead electrode 91 and the common lead electrode 92 (hereinafter collectively referred to as the lead electrode 90) are made of the same layer but are electrically discontinuous.

Here, the individual lead electrode 91 is formed on the first electrode 60 provided on the outside of the piezoelectric layer 70, and in the present embodiment, on the same electrode layer as the second electrode 80 provided on the first electrode 60. It is pulled out to the top of the diaphragm 50.
Further, the common lead electrode 92 is drawn in the second direction Y from the second electrode 80 to the diaphragm 50 at both ends in the first direction X.

  In addition, the common lead electrode 92 may include extending portions 93 that are continuously provided across the plurality of active portions 310 on both sides of the concave portion 71 in the second direction Y. In the present embodiment, the extending portion 93 is provided on the wall surface of the pressure generation chamber 12 in the second direction Y, that is, across the boundary portion between the flexible portion and the non-flexible portion. That is, the extending portion 93 is provided continuously in the first direction X of the plurality of active portions 310, and continues to the common lead electrode 92 at both ends in the first direction X. That is, the common lead electrode 92 having the extending portion 93 is continuously disposed so as to surround the active portion 310 when viewed in plan from the protective substrate 30 side. Thus, by providing the extending portion 93, it is possible to suppress variation in the voltage applied to the active portion 310 due to a wiring resistance difference when a voltage is applied to the second electrode 80 that is a common electrode. That is, in the present embodiment, since the second electrode 80 is not provided in the recess 71 of the piezoelectric layer 70, the second electrode 80 extends over the plurality of active portions 310 only on both sides in the second direction Y of the recess 71. Are continuous. Accordingly, the electrical resistance value of the second electrode 80 is increased, and a large number of ink droplets are simultaneously driven by simultaneously driving a large number of active portions 310 as compared with a case where one or a small number of active portions 310 are driven individually or simultaneously. When ejected, a voltage drop occurs and the amount of displacement of the active portion 310 becomes unstable, resulting in a decrease and variation in ink ejection characteristics. In the present embodiment, by providing the extending portion 93, it is possible to suppress the voltage drop of the second electrode 80 and to suppress the deterioration and variation in the ink ejection characteristics. Further, by providing the extending portion 93, it is possible to suppress the destruction of the piezoelectric layer 70 due to stress concentration at the boundary between the flexible portion and the non-flexible portion. Further, since the common lead electrode 92 is not substantially formed on the flexible portion, it is possible to suppress a decrease in displacement of the active portion 310. Such an extended portion 93 is possible when the length of the recess 71 shown in FIG. 5A described above, that is, the second direction Y of the recess 71 is shorter than the pressure generation chamber 12. That is, when the recessed portion 71 is provided to the outside of the pressure generating chamber 12 as shown in FIG. 5B, when the extending portion 93 is provided at the boundary between the flexible portion and the non-flexible portion, the extending portion 93 is This is because it is also formed on the protective film 200 provided in the recess 71.

  As shown in FIGS. 1 and 3, a protective substrate 30 that protects the piezoelectric element 300 is bonded to the flow path forming substrate 10 on which the piezoelectric element 300 is formed by an adhesive 35. The protective substrate 30 is provided with a piezoelectric element holding portion 31 that is a recess that defines a space for accommodating the piezoelectric element 300. The protective substrate 30 is provided with a manifold portion 32 that constitutes a part of the manifold 100. The manifold portion 32 penetrates the protective substrate 30 in the thickness direction and is formed across the width direction of the pressure generating chamber 12 and communicates with the communication portion 15 of the flow path forming substrate 10 as described above. The protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. The lead electrode 90 (individual lead electrode 91 and common lead electrode 92) connected to the first electrode 60 of each active part 310 is provided so as to be exposed in the through hole 33.

  A driving circuit 120 that functions as a signal processing unit is fixed on the protective substrate 30. As the drive circuit 120, for example, a circuit board, a semiconductor integrated circuit (IC), or the like can be used. The drive circuit 120 and the lead electrode 90 are electrically connected via a connection wiring 121 (external wiring in the present embodiment) made of a conductive wire such as a bonding wire having the through-hole 33 inserted therethrough. The external wiring is not limited to the connection wiring 121 made of a conductive wire. For example, a flexible printed circuit board (FPC) such as a chip on film (COF) or a tape carrier package (TCP) is connected to the lead electrode 90. It may be.

  On the protective substrate 30, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded. The sealing film 41 is made of a material having low rigidity and flexibility, and one surface of the manifold portion 32 is sealed by the sealing film 41. The fixing plate 42 is made of a hard material such as metal. Since the area of the fixing plate 42 facing the manifold 100 is an opening 43 that is completely removed in the thickness direction, one surface of the manifold 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head I of this embodiment, after taking ink from an ink introduction port connected to an external ink supply means (not shown) and filling the interior from the manifold 100 to the nozzle opening 21, the drive circuit 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 the recording signal from. As a result, the diaphragm 50 is bent and deformed together with the piezoelectric element 300 to increase the pressure in each pressure generating chamber 12, and an ink droplet is ejected from each nozzle opening 21.

  Here, a method for manufacturing the ink jet recording head of the present embodiment will be described. 6 to 11 are cross-sectional views showing a method for manufacturing the ink jet recording head.

  First, as shown in FIG. 6A, an elastic film 51 is formed on the surface of a flow path forming substrate wafer 110 that is a silicon wafer. In the present embodiment, the elastic film 51 made of silicon dioxide is formed by thermally oxidizing the flow path forming substrate wafer 110. Of course, the material of the elastic film 51 is not limited to silicon dioxide, and may be a silicon nitride film, a polysilicon film, an organic film (such as polyimide or parylene), or the like. The formation method of the elastic film 51 is not limited to thermal oxidation, and may be formed by a sputtering method, a CVD method, a spin coating method, or the like.

Next, as shown in FIG. 6B, an insulator film 52 made of zirconium oxide is formed on the elastic film 51. Of course, the insulator film 52 is not limited to zirconium oxide, and titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), magnesium oxide (MgO), lanthanum aluminate (LaAlO _3). ) Etc. may be used. Examples of a method for forming the insulator film 52 include a sputtering method, a CVD method, and a vapor deposition method. In the present embodiment, the diaphragm 50 is formed by the elastic film 51 and the insulator film 52, but only one of the elastic film 51 and the insulator film 52 may be provided as the diaphragm 50.

  Next, as shown in FIG. 6C, the first electrode 60 is formed on the entire surface of the diaphragm 50. The material of the first electrode 60 is not particularly limited, but the conductivity is not lost by oxidation during heat treatment (generally 500 ° C. or higher) or diffusion of the material contained in the piezoelectric layer 70 when the piezoelectric layer 70 is formed. It is essential to be a material. For this reason, the material of the first electrode 60 is preferably a metal such as platinum or iridium that does not lose conductivity even at a high temperature, a conductive oxide such as iridium oxide or lanthanum nickel oxide, or a laminated material of these materials. Used. The first electrode 60 can be formed by, for example, vapor phase film formation such as sputtering, PVD (physical vapor deposition), or laser ablation, or liquid phase film formation such as spin coating. Further, an adhesion layer for ensuring adhesion can be used between the conductive material described above and the diaphragm 50. In this embodiment, although not particularly shown, titanium is used as the adhesion layer. As the adhesion layer, zirconium, titanium, titanium oxide, or the like can be used. The method for forming the adhesion layer is the same as that for the electrode material. In addition, a control layer for controlling crystal growth of the piezoelectric layer 70 may be formed on the electrode surface (film formation side of the piezoelectric layer 70). In this embodiment, titanium is used for crystal control of the piezoelectric layer 70 (PZT). Since titanium is taken into the piezoelectric layer 70 when the piezoelectric layer 70 is formed, it does not exist as a film after the piezoelectric layer 70 is formed. As the crystal control layer, a conductive oxide having a perovskite crystal structure such as lanthanum nickel oxide may be used. The method for forming the crystal control layer is the same as that for the electrode material. It is desirable that the insulating crystal control layer does not exist between the piezoelectric layer 70 and the first electrode 60 after the piezoelectric layer 70 is formed. This is because the electric field applied to the piezoelectric layer 70 is reduced because the crystal control layer and the capacitor of the piezoelectric layer 70 are connected in series. As in the present embodiment, by using titanium as the orientation control layer, it is subjected to a heat treatment that would otherwise be an oxide (insulator), but does not exist as a film because it is taken into the piezoelectric layer 70.

  Next, in this embodiment, the piezoelectric layer 70 made of lead zirconate titanate (PZT) is formed. Here, in this embodiment, a so-called sol-gel in which a so-called sol in which a metal complex is dissolved / dispersed in a solvent is applied, dried, gelled, and further fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. The piezoelectric layer 70 is formed using the method. The method for manufacturing the piezoelectric layer 70 is not limited to the sol-gel method, and for example, using a MOD (Metal-Organic Decomposition) method, a PVD (Physical Vapor Deposition) method such as a sputtering method or a laser ablation method. Also good. That is, the piezoelectric layer 70 may be formed by either a liquid phase method or a gas phase method. In the present embodiment, the piezoelectric layer 70 is formed by laminating a plurality of piezoelectric films 74.

  Specifically, as shown in FIG. 7A, when the first piezoelectric film 74 is formed on the first electrode 60, the first electrode 60 and the first piezoelectric film 74 are simultaneously formed. Pattern. The patterning of the first electrode 60 and the first piezoelectric film 74 can be performed by dry etching such as reactive ion etching (RIE) or ion milling, for example.

  Here, for example, when the first piezoelectric film 74 is formed after patterning the first electrode 60, the first electrode 60 is patterned because the first electrode 60 is patterned by a photo process, ion milling, and ashing. The surface and a crystal seed layer such as titanium (not shown) provided on the surface are denatured. Then, even if the piezoelectric film 74 is formed on the altered surface, the crystallinity of the piezoelectric film 74 is not good, and the second and subsequent piezoelectric films 74 are also crystals of the first piezoelectric film 74. Since the crystal growth is influenced by the state, the piezoelectric layer 70 having good crystallinity cannot be formed.

  In contrast, if the first piezoelectric film 74 is formed and then patterned at the same time as the first electrode 60, the first piezoelectric film 74 is the second and subsequent piezoelectric films compared to the crystal species such as titanium. The seed 74 has a strong property as a seed (crystal seed) for satisfactorily growing a crystal, and even if an extremely thin altered layer is formed on the surface layer by patterning, the crystal growth of the second and subsequent piezoelectric films 74 is not greatly affected. .

  When the second and subsequent piezoelectric films 74 are formed on the diaphragm 50 exposed before forming the second piezoelectric film 74, a crystal control layer (intermediate crystal control layer) is formed. It may be used. In this embodiment, titanium is used as the intermediate crystal control layer. The intermediate crystal control layer made of titanium is taken into the piezoelectric film 74 when the piezoelectric film 74 is formed, similarly to the titanium of the crystal control layer formed on the first electrode 60. Incidentally, if the intermediate crystal control layer becomes a dielectric of an intermediate electrode or a capacitor connected in series, it causes a decrease in piezoelectric characteristics. Therefore, it is desirable that the intermediate crystal control layer is taken into the piezoelectric film 74 (piezoelectric layer 70) and does not remain as a film after the piezoelectric layer 70 is formed.

Next, as shown in FIG. 7B, a piezoelectric layer 70 composed of a plurality of piezoelectric films 74 is formed by laminating the second and subsequent layers of piezoelectric films 74.
Incidentally, the second and subsequent piezoelectric films 74 are continuous over the diaphragm 50, on the side surfaces of the first electrode 60 and the first piezoelectric film 74, and over the first piezoelectric film 74. Formed.

  Next, as shown in FIG. 7C, the piezoelectric layer 70 is patterned to form the recesses 71 and the like. In the present embodiment, patterning is performed by so-called photolithography, in which a mask (not shown) having a predetermined shape is provided on the piezoelectric layer 70, and the piezoelectric layer 70 is etched through the mask. The patterning of the piezoelectric layer 70 may be, for example, dry etching such as reactive ion etching or ion milling, or wet etching using an etching solution.

  Incidentally, when the piezoelectric layer 70 is patterned by wet etching using an etching solution, a plurality of flow path forming substrate wafers 110 can be processed simultaneously by batch processing, so that the manufacturing cost can be reduced. However, in the patterning of the piezoelectric layer 70 by wet etching, irregularities are easily formed on the etched surface. However, in this embodiment, as described above, the side surface (etched surface) in the recess 71 of the piezoelectric layer 70 is formed in a later step. ), The second electrode 80 is not formed, so that it is possible to suppress the generation of foreign matter due to the second electrode 80 dropping off, the formation failure of the second electrode 80, and the like.

  Next, as shown in FIG. 8A, on the patterned side surface of the piezoelectric layer 70 over one surface side (the surface side on which the piezoelectric layer 70 is formed) of the flow path forming substrate wafer 110, A second electrode 80 is formed over the diaphragm 50 and the first electrode 60 and patterned.

  In the present embodiment, the second electrode 80 is formed from the surface of the piezoelectric layer 70 opposite to the flow path forming substrate wafer 110 and the region of the first electrode 60 that is not covered by the piezoelectric layer 70. The layer 70 is formed up to the top. Further, the second electrode 80 is not formed on the side surface of the recess 71 of the piezoelectric layer 70.

  In this embodiment, after the piezoelectric layer 70 is patterned, the second electrode 80 is formed and patterned. However, the present invention is not limited to this, and the second electrode 80 is patterned before the piezoelectric layer 70 is patterned. After forming 80, patterning of the second electrode 80 and the piezoelectric layer 70 may be performed.

  Thus, by not forming the second electrode 80 on the side surface of the concave portion 71 of the piezoelectric layer 70, it is possible to suppress the second electrode 80 from being peeled off and becoming a foreign substance or from being disconnected. Accordingly, the side surface of the concave portion 71 of the piezoelectric layer 70 is steep, that is, formed at an angle close to perpendicular to the surface of the flow path forming substrate 10 (flow path forming substrate wafer 110), Unevenness (roughness) can be increased. Therefore, the side surfaces of the recesses 71 of the piezoelectric layer 70 can be sharpened so that the piezoelectric layers 70 can be arranged at a high density, and the patterning method of the piezoelectric layer 70 is not limited, and the patterning can be performed efficiently and at a low cost. can do.

  In addition, since the second electrode 80 is not formed on the side surface of the concave portion 71 of the piezoelectric layer 70, it is possible to suppress poor contact with the side surface of the second electrode 80. The displacement characteristics of the piezoelectric element 300 (active part 310) can be improved by making it relatively thin.

Next, as shown in FIG. 8B, a protective film 200 is formed in the recess 71. In this embodiment, the protective film 200 made of an organic insulating material such as polyimide is formed so as to be filled in the recess 71 by spin coating. By providing the protective film 200 in this way, the side surfaces of the piezoelectric layer 70, particularly the side surfaces in the recesses 71, are reliably protected by the protective film 200, and the piezoelectric layer 70 is destroyed by moisture contained in the atmosphere. Can be suppressed.
The protective film 200 may be formed, for example, after forming the recess 71 in the piezoelectric layer 70 and before forming the second electrode 80.

Next, although not shown, the lead electrode 90 is formed and patterned into a predetermined shape.
Next, as shown in FIG. 9A, a protective substrate wafer 130 that is a silicon wafer and serves as a plurality of protective substrates 30 is disposed on the piezoelectric element 300 side of the flow path forming substrate wafer 110 via an adhesive 35. After bonding, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  Next, as shown in FIG. 9B, a mask film 53 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, as shown in FIG. 9C, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) using an alkaline solution such as KOH through the mask film 53, so that the piezoelectric element 300 is formed. Corresponding pressure generating chambers 12, ink supply passages 13, communication passages 14, communication portions 15 and the like are formed.

  Thereafter, 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 having the nozzle openings 21 formed on the surface of the flow path forming substrate wafer 110 opposite to the protective substrate wafer 130 is bonded, and the compliance substrate 40 is bonded to the protective substrate wafer 130. By dividing the flow path forming substrate wafer 110 and the like into a single chip size flow path forming substrate 10 and the like as shown in FIG. 1, the ink jet recording head of this embodiment is obtained.

  In this embodiment, the second electrode 80 extends from the piezoelectric layer 70 to the first electrode 60, and the second electrode 80 of the active part 310 and the electrode on the first electrode 60 are separated by the removing unit 83. Although it is made discontinuous, it is not particularly limited to this. Here, another example is shown in FIG. FIG. 10 is a cross-sectional view of an ink jet recording head which is an example of a liquid jet head according to another embodiment of the present invention.

  As shown in FIG. 10, the second electrode 80 is formed on the piezoelectric layer 70, that is, on the opposite side of the piezoelectric layer 70 from the flow path forming substrate 10. The piezoelectric layer 70 and the second electrode 80 are formed to have the same shape when viewed in plan. In such a configuration, the patterning of the piezoelectric layer 70 and the patterning of the second electrode 80 can be performed simultaneously. Of course, even with such a configuration, the patterning of the piezoelectric layer 70 and the patterning of the second electrode 80 may be performed in separate steps. When patterning the piezoelectric layer 70 and the second electrode 80 in separate steps, for example, the second electrode 80 may have a slightly smaller area than the piezoelectric layer 70 in plan view.

  Further, the ink jet recording head of this embodiment constitutes a part of an ink jet recording head unit including an ink flow path communicating with a cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 11 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus II shown in FIG. 11, ink jet recording head units 1A and 1B (hereinafter also referred to as head units 1A and 1B) each having a plurality of ink jet recording heads I include a cartridge 2A and an ink supply unit. 2B is detachably provided, and the carriage 3 on which the 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 head units 1A and 1B, for example, discharge a black ink composition and a color ink composition, respectively.

  Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the head units 1A and 1B are mounted is moved along the carriage shaft 5. . 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.

  In the ink jet recording apparatus II described above, the ink jet recording head I (head units 1A, 1B) is mounted on the carriage 3 and moved in the main scanning direction. The present invention can also be applied to a so-called line recording apparatus in which the ink jet recording head I is fixed and printing is performed simply by moving the recording sheet S such as paper in the sub-scanning direction.

  In the above-described example, the ink jet recording apparatus II has a configuration in which the cartridges 2A and 2B, which are liquid storage units, are mounted on the carriage 3. However, the invention is not particularly limited thereto, and for example, a liquid storage such as an ink tank or the like. The means may be fixed to the apparatus body 4 and the storage means and the ink jet recording head I may be connected via a supply pipe such as a tube. Further, the liquid storage means may not be mounted on the ink jet recording apparatus II.

(Embodiment 2)
Hereinafter, an ultrasonic sensor according to an embodiment of the present invention will be described. Note that the present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not necessarily. Further, the same members as those in the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, transmission and reception of ultrasonic waves are performed using an electroacoustic modifier that uses the piezoelectric effect. Such an electroacoustic transducer is a piezoelectric element, which utilizes electrical energy converted to mechanical energy (inverse piezoelectric effect) when transmitting ultrasonic waves, and changes due to contraction and expansion of the piezoelectric layer cause the diaphragm to vibrate. Ultrasound is transmitted by exciting. Therefore, in this case, the piezoelectric element is a transmitting ultrasonic transducer.

  Furthermore, in order to receive the ultrasonic waves reflected from the detection object, mechanical energy is converted into electric energy (positive piezoelectric effect), and electric energy is generated by deformation of the piezoelectric layer, and an electric energy signal is detected. . Therefore, in this case, the piezoelectric element is a receiving ultrasonic transducer.

  In the present embodiment, the piezoelectric element (ultrasonic transducer) is a diaphragm, a first electrode provided on the diaphragm, a piezoelectric layer provided on the first electrode, and a piezoelectric body. And a second electrode provided on the layer. The first electrode can also be used as a diaphragm.

FIG. 12 is a plan view of an ultrasonic device equipped with the ultrasonic transducer according to the second embodiment of the present invention and a cross-sectional view taken along the line EE ′.
As shown in FIG. 12A, a plurality of transmitting ultrasonic transducers 301 and receiving ultrasonic transducers 302 are provided in an array on the substrate 10 having the substrate opening 12, and the ultrasonic device 400 ( Array sensor). A plurality of transmitting ultrasonic transducers 301 and a plurality of receiving ultrasonic transducers 302 are alternately arranged for each column, and energization is switched for each transducer column. Line scan and sector scan are realized according to such switching of energization. Further, the output level and input level of the ultrasonic wave are determined according to the number of transducers to be energized and the number of rows. In the figure, it is omitted and 6 rows × 6 columns are drawn. The number of rows and the number of columns in the array are determined according to the spread of the scan range.

  It is also possible to alternately arrange the transmitting ultrasonic transducer 301 and the receiving ultrasonic transducer 302 for each transducer. In this case, it is easy to match the directivity angles of transmission and reception by using an ultrasonic transmission / reception source that combines the central axes of the transmission side and the reception side.

  In this embodiment, both the transmitting ultrasonic transducer 301 and the receiving ultrasonic transducer 302 are arranged on a single substrate 10 in order to reduce the size of the device. The transmitting ultrasonic transducer 301 and the receiving ultrasonic transducer 302 can be arranged on independent substrates, or a plurality of substrates can be used depending on the application. Furthermore, it is possible to provide both the functions of transmission and reception in one ultrasonic transducer using the time difference between transmission and reception.

In FIG. 12B, as an example that can be used as an ultrasonic transducer, for example, the substrate 10 is made of single crystal silicon having a (100), (110), or (111) orientation. Alternatively, besides silicon materials, ceramic materials typified by ZrO ₂ or Al ₂ O ₃ , glass ceramic materials, oxide substrate materials such as MgO and LaAlO ₃ , SiC, SiO ₂ , polycrystalline silicon, Si ₃ N ₄ Inorganic materials such as can also be used. Or the laminated material by the combination of these materials may be sufficient.

A vibration plate 50 is formed above the substrate 10 (on the piezoelectric layer 70 side). The diaphragm 50 can be used by thinning a part of the substrate 10, but the piezoelectric layer 70 or the first electrode 60 may be used. It is also possible to form a film using another material. In this case, for example, silicon compounds such as SiO ₂ , SiC and Si ₃ N ₄ , polycrystalline silicon, ceramic materials such as ZrO ₂ and Al ₂ O ₃ , oxides such as MgO, LaAlO ₃ and TiO ₂ You can do it. The film thickness and material selection are determined based on the resonance frequency. The surface layer of the diaphragm 50 on the piezoelectric layer 70 side is preferably made of a material that can prevent the diffusion of the piezoelectric layer material, such as ZrO ₂ . In this case, the transmission and reception characteristics of the transducer are improved by improving the piezoelectric characteristics of the piezoelectric layer.

  A substrate opening 12 which is an opening is formed in the substrate 10. The substrate opening 12 can be formed using a processing method such as etching, polishing, or laser processing depending on the substrate material.

  Since the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are the same as those in the first embodiment, description of the configuration is omitted. In contrast to the first embodiment, the ultrasonic device needs to be driven in a higher frequency region than the liquid jet head typified by the ink jet recording head I. Therefore, the piezoelectric layer 70, the diaphragm 50, and each Physical property values such as the thickness and Young's modulus of the electrode material may be adjusted.

  Further, wiring (not shown) is connected to the transmitting ultrasonic transducer 301 and the receiving ultrasonic transducer 302, and each wiring is a terminal of a control board (not shown) via a flexible printed board (not shown). Connected to a portion (not shown). The control board is provided with a control unit (not shown) including a calculation unit and a storage unit. The control unit is configured to control an input signal input to the transmitting ultrasonic transducer 301 and process an output signal output from the receiving ultrasonic transducer 302.

As described above, in the ultrasonic device 400 of the present application, the piezoelectric elements 300 created using the MEMS technology can be arranged at a narrow pitch (high resolution) as compared with a sensor using a bulk type piezoelectric ceramic or the like, and the drive voltage Therefore, the device and the apparatus on which the device is mounted are effective in reducing the size, thickness, and energy. In addition, since the manufacturing variation between the piezoelectric elements 300 is small, there is an effect that the recognition accuracy is increased.
In addition, by reducing the film thickness of the piezoelectric layer 70, it is possible to improve the displacement characteristics and improve the efficiency of transmitting and receiving ultrasonic waves.

  Furthermore, in the present embodiment, the concave portion 71 is provided in the piezoelectric layer 70, and the second electrode 80 is not provided on the side surface in the concave portion 71. For this reason, peeling and disconnection of the second electrode 80 can be suppressed. Therefore, the wall surface of the recess 71 of the piezoelectric layer 70 can be made perpendicular to the substrate 10 and the ultrasonic transducers 301 and 302 can be arranged with high density. In the present embodiment, the side surfaces of the piezoelectric layer 70 used for the ultrasonic transducers 301 and 302 are covered with the protective film 200, so that the ultrasonic transducers 301 and 302 are prevented from being broken. be able to.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, the fundamental structure of this invention is not limited to what was mentioned above.
For example, in the first embodiment described above, the present invention has been described by taking an ink jet recording head as an example of a liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads. Examples of the liquid ejecting head include various recording heads used in image recording apparatuses such as printers, color material ejecting heads used for manufacturing color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  In addition, the present invention is not limited to a liquid ejecting head typified by an ink jet recording head or a piezoelectric element mounted on an ultrasonic sensor, but a piezoelectric device mounted on another device such as an ultrasonic motor, a pressure sensor, or a pyroelectric sensor. It can also be applied to elements. The present invention can be similarly applied to a ferroelectric element such as a ferroelectric memory.

  I ink jet recording head (liquid ejecting head), II ink jet recording apparatus (liquid ejecting apparatus), 10 flow path forming substrate (substrate), 11 partition, 12 pressure generating chamber, 13 ink supply path, 14 communication path, 15 communication Part, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 31 piezoelectric element holding part, 32 manifold part, 33 through hole, 35 adhesive, 40 compliance board, 41 sealing film, 42 fixing plate, 43 opening part, 50 Diaphragm, 51 Elastic film, 52 Insulator film, 60 First electrode, 70 Piezoelectric layer, 71 Recess, 80 Second electrode, 90 Lead electrode (wiring layer), 100 Manifold, 300 Piezoelectric element, 310 Active part, 301 Ultrasonic transducer for transmission, 302 Ultra for reception Wave transducer, 400 ultrasound device

Claims (9)

A flow path forming substrate provided with a pressure generating chamber communicating with a nozzle opening for ejecting liquid;
A liquid ejecting head provided on one surface side of the flow path forming substrate and including a first electrode, a piezoelectric layer, and a piezoelectric element having a second electrode,
A plurality of active portions that are substantially driving portions sandwiched between the first electrode and the second electrode;
The first electrode is an individual electrode provided for each active part,
The second electrode is a common electrode provided across a plurality of the active portions;
The piezoelectric layer is provided over a plurality of active portions, and the piezoelectric layer is provided with a recess between the plurality of active portions,
The liquid ejecting head, wherein the second electrode is not formed on at least a side surface of the recess.   The liquid jet head according to claim 1, wherein a protective film made of an insulating material is formed on at least a side surface of the recess.   The liquid ejecting head according to claim 2, wherein the protective film is made of a material having a Young's modulus smaller than that of the second electrode.   The liquid jet head according to claim 2, wherein the protective film has a tensile stress as an internal stress.   5. The wiring layer according to claim 1, further comprising a wiring layer provided continuously over the plurality of active portions in a region other than the concave portion on the second electrode. Liquid jet head.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1. A piezoelectric element having a first electrode, a piezoelectric layer, and a second electrode,
A plurality of active portions that are substantially driving portions sandwiched between the first electrode and the second electrode;
The first electrode is an individual electrode provided for each active part,
The second electrode is a common electrode provided across a plurality of the active portions;
The piezoelectric layer is provided over a plurality of active portions, and the piezoelectric layer is provided with a recess between the plurality of active portions,
The piezoelectric element, wherein the second electrode is not formed on at least a side surface of the recess.   An ultrasonic transducer comprising at least the piezoelectric element according to claim 7. A substrate having an opening;
The ultrasonic transducer according to claim 8 provided on the substrate;
An ultrasonic device comprising:

Images