Patent Publication Number: US-2021184099-A1

Title: Piezoelectric Element, Piezoelectric Actuator, Ultrasonic Probe, Ultrasonic Apparatus, Electronic Apparatus, Liquid Jet Head, And Liquid Jet Apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 15/935,492 filed Mar. 26, 2018, which claims the benefit of Japanese Patent Application no. 2017-061459 filed Mar. 27, 2017, the entire disclosures of which are expressly incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a piezoelectric element, a piezoelectric actuator, an ultrasonic probe, an ultrasonic apparatus, an electronic apparatus, a liquid jet head, and a liquid jet apparatus. 
     2. Related Art 
     A known piezoelectric element for vibrating a driver such as a vibrating film is described in JP-A-2015-66202. 
     In JP-A-2015-66202, there is disclosed an ultrasonic device provided with a piezoelectric element. This ultrasonic device has a base body having a plurality of apertures respectively provided with vibrating films, and on each of the vibrating films, there is disposed a piezoelectric element formed of a lower electrode, a piezoelectric layer, and an upper electrode stacked on one another. Further, on the surface of the base body, there is disposed a plurality of first conductive films in a column direction, and a plurality of second conductive films in a row direction. The first conductive films each form the lower electrodes on the vibrating films, and the second conductive films each form the upper electrodes on the vibrating films. 
     Incidentally, in such a piezoelectric element as in JP-A-2015-66202 described above, the formation material of the piezoelectric layer is formed on the first conductive layer on the base body, and then the formation material is etched by ion milling or the like to thereby pattern the piezoelectric layer. When etching the piezoelectric layer, a part of the first conductive layer is thinned due to over etching. In particular, in an edge part of the piezoelectric layer, the etch rate becomes high, and breaking occurs in the first conductive layer in some cases. If breaking occurs in the first conductive layer as described above, the piezoelectric element deteriorates in function or becomes unable to drive, and there arises a problem that the reliability of the piezoelectric element degrades. 
     SUMMARY 
     An advantage of some aspects of the invention is to provide a piezoelectric element, a piezoelectric actuator, an ultrasonic probe, an ultrasonic apparatus, an electronic apparatus, a liquid jet head, and a liquid jet apparatus each high in reliability. 
     A piezoelectric element according to an application example of the invention includes a first electrode layer, a piezoelectric layer, and a second electrode layer, the first electrode layer, the piezoelectric layer, and the second electrode layer are stacked in sequence on one another, the first electrode layer has a first part overlapping the piezoelectric layer in a plan view viewed from a stacking direction of the first electrode layer, the piezoelectric layer, and the second electrode layer, and a second part at least partially separated from the first part and not overlapping the piezoelectric layer in the plan view, the second electrode layer has a third part overlapping the piezoelectric layer in the plan view, and a fourth part separated from the third part, and the fourth part has contact with the first part and the second part. 
     In this application example, the first electrode layer is provided with the first part overlapping the piezoelectric layer in the plan view and the second part not overlapping the piezoelectric layer and partially separated from the first part. Further, the second electrode layer is provided with the third part overlapping the piezoelectric layer to sandwich the piezoelectric layer together with the first part, and the fourth part separated from the third part. Further, the fourth part has contact with the first part and the second part of the first electrode layer. Therefore, it results that the first part and the second part of the first electrode layer are electrically connected to each other by the fourth part of the second electrode layer, and thus, the problem that breaking occurs between the first part and the second part can be prevented. Therefore, it is possible to appropriately input the signal for driving the piezoelectric element from the second part to the first part of the first electrode layer, and thus, it is possible to provide the piezoelectric element high in reliability. 
     Further, since the fourth part of the second electrode layer is disposed separately from the third part, there is no chance for the first electrode layer and the second electrode layer to be electrically connected to each other via the fourth part, and it is possible to appropriately apply the drive voltage to the piezoelectric layer using the first part of the first electrode layer and the third part of the second electrode layer to drive the piezoelectric element. 
     In the piezoelectric element according to the application example, it is preferable that the fourth part fills in the separated part between the first part and the second part. 
     In the application example with this configuration, the fourth part is disposed so as to fill in the separated part between the first part and the second part. Therefore, breaking between the first part and the second part can more surely be prevented to enhance the reliability of the piezoelectric element. 
     A piezoelectric element according to an application example of the invention includes a first electrode layer, a piezoelectric layer, a second electrode layer, a first conductive layer, and a second conductive layer, the first electrode layer, the piezoelectric layer, and the second electrode layer are stacked in sequence on one another, the first electrode layer and the second electrode layer overlap the piezoelectric layer in a plan view viewed from a stacking direction of the first electrode layer, the piezoelectric layer, and the second electrode layer, the first conductive layer is partially separated from the first electrode layer, and does not overlap the piezoelectric layer in the plan view, the second conductive layer is separated from the second electrode layer, and the second conductive layer has contact with the first electrode layer and the first conductive layer. 
     In this application example, the signal is input from the first conductive layer to the first electrode layer to thereby drive the piezoelectric layer. As such, since the first electrode layer and the first conductive layer have contact with the second conductive layer, even in the case in which there is a void between the first electrode layer and the first conductive layer, it is possible to electrically connect the first electrode layer and the first conductive layer to each other via the second conductive layer. In other words, in this application example, breaking between the first electrode layer and the first conductive layer can be prevented, and thus, it is possible to provide a piezoelectric element high in reliability. 
     In the piezoelectric element according to the application example, it is preferable that the second conductive layer is larger in thickness dimension (thicker) than the second electrode layer. 
     In the application example with this configuration, since the second conductive layer is larger in thickness dimension than the second electrode layer, it is possible to reduce the electrical resistance between the first electrode layer and the conductive layer, and thus, it becomes possible to apply a signal with a desired voltage value to the first electrode layer. Further, since the second electrode layer is smaller in thickness dimension (thinner) then the second conductive layer, it is possible to increase the displacement of the piezoelectric layer when applying the voltage between the first electrode layer and the second electrode layer. 
     In the piezoelectric element according to the application example, it is preferable that the second conductive layer fills in a separated part between the first electrode layer and the first conductive layer. 
     In the application example with this configuration, the second conductive layer is disposed so as to fill in the separated part between the first electrode layer and the first conductive layer. Therefore, breaking between the first electrode layer and the second conductive layer can more surely be prevented to enhance the reliability of the piezoelectric element. 
     A piezoelectric actuator according to an application example of the invention includes the piezoelectric element described above, and a driver driven by the piezoelectric element. 
     In this application example, the driver is driven by a piezoelectric element such as described above. Here, the piezoelectric element can appropriately input the signal to the first electrode layer similarly to the application examples described above, and thus, the reliability of the piezoelectric element can be enhanced. Therefore, the reliability in the piezoelectric actuator can also be enhanced. 
     An ultrasonic probe according to an application example of the invention includes the piezoelectric actuator described above, and a housing configured to house the piezoelectric actuator, and the piezoelectric element drives the driver to one of transmit and receive an ultrasonic wave. 
     The ultrasonic probe according to this application example houses the piezoelectric actuator in the housing, and vibrates the driver (vibrating section) with the piezoelectric element, and thus, it becomes possible to perform the transmission and reception of the ultrasonic wave. Here, the piezoelectric actuator is provided with the piezoelectric element capable of appropriately inputting the signal to the first electrode layer similarly to the application examples described above, and thus, the reliability of the piezoelectric actuator can be enhanced. Therefore, the reliability in the ultrasonic probe having such a piezoelectric actuator can also be enhanced. 
     An ultrasonic apparatus according to an application example of the invention includes the piezoelectric actuator described above, and a controller configured to control the piezoelectric actuator, and the piezoelectric element drives the driver to one of transmit and receive an ultrasonic wave. 
     The ultrasonic apparatus according to this application example can perform the transmission and the reception of the ultrasonic wave by controlling the piezoelectric actuator using the controller to drive the driver, and the controller can, for example, form an internal tomographic image of the test object or give a diagnosis on the internal structure of the test object based on the reception result of the ultrasonic wave. Here, the piezoelectric actuator is provided with the piezoelectric element capable of appropriately inputting the signal to the first electrode layer similarly to the application examples described above, and thus, the reliability of the piezoelectric actuator can be enhanced. Therefore, the reliability in the ultrasonic apparatus having such a piezoelectric actuator can also be enhanced. 
     An electronic apparatus according to an application example of the invention includes the piezoelectric element described above, and a controller configured to control the piezoelectric element. 
     The electronic apparatus according to this application example controls the piezoelectric actuator with the controller to drive the driver to thereby perform a variety of operations. As such an electronic apparatus, there can widely be used as, for example, a displacement detection sensor for detecting the displacement of the driver with the piezoelectric element besides a drive apparatus for driving the driver to displace the object. Here, the piezoelectric actuator is provided with the piezoelectric element capable of appropriately inputting the signal to the first electrode layer similarly to the application examples described above, and thus, the reliability of the piezoelectric actuator can be enhanced. Therefore, the reliability in the electronic apparatus having such a piezoelectric actuator can also be enhanced. 
     A liquid jet head according to an application example of the invention includes the piezoelectric actuator described above. 
     In the liquid jet head according to this application example, by driving the driver with the piezoelectric actuator, it is possible to jet the liquid reserved in, for example, a tank from a nozzle. Here, the piezoelectric actuator is provided with the piezoelectric element capable of appropriately inputting the signal to the first electrode layer similarly to the application examples described above, and thus, the reliability of the piezoelectric actuator can be enhanced. Therefore, the reliability in the liquid jet head having such a piezoelectric actuator can also be enhanced. 
     A liquid jet apparatus according to an application example of the invention is equipped with the liquid jet head described above. 
     In this application example, the liquid jet apparatus is equipped with the liquid jet head high in reliability as described above, and thus, the reliability in the liquid jet apparatus can also be enhanced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a perspective view showing a general configuration of an ultrasonic measurement apparatus according to a first embodiment of the invention. 
         FIG. 2  is a cross-sectional view showing a schematic configuration of an ultrasonic probe according to the first embodiment. 
         FIG. 3  is a plan view of a part of an element substrate constituting an ultrasonic device according to the first embodiment viewed from a sealing plate side. 
         FIG. 4  is a cross-sectional view of the ultrasonic device cut along the line A-A shown in  FIG. 3 . 
         FIG. 5  is a plan view of an ultrasonic transducer provided to the element substrate of the first embodiment viewed from the sealing plate side. 
         FIG. 6  is a cross-sectional view of a part of the ultrasonic transducer cut along the line B-B shown in  FIG. 5 . 
         FIG. 7  is a diagram showing an example of a vicinity of a boundary between a lower electrode main body and a lower electrode connection part formed on the vibrating film of the first embodiment. 
         FIG. 8  is a diagram showing another example of the vicinity of the boundary between the lower electrode main body and the lower electrode connection part formed on the vibrating film of the first embodiment. 
         FIG. 9  is a flowchart showing a method of manufacturing a piezoelectric element according to the first embodiment. 
         FIG. 10  is a diagram showing a manufacturing process of the piezoelectric element in the respective steps of  FIG. 9 . 
         FIG. 11  is a cross-sectional view showing a part of an ultrasonic transducer according to a second embodiment of the invention. 
         FIG. 12  is a flowchart showing a method of manufacturing a piezoelectric element according to the second embodiment. 
         FIG. 13  is a diagram showing a manufacturing process of the piezoelectric element on and after the step S 11  of  FIG. 12 . 
         FIG. 14  is a diagram showing a configuration example of an appearance of a printer according to a third embodiment of the invention. 
         FIG. 15  is an exploded perspective view of a recording head provided to the printer according to the third embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     First Embodiment 
     A first embodiment of the invention will hereinafter be described based on the drawings. 
       FIG. 1  is a perspective view showing a schematic configuration of the ultrasonic measurement apparatus  1 . 
     As shown in  FIG. 1 , the ultrasonic measurement apparatus  1  corresponds to the ultrasonic apparatus, and is provided with an ultrasonic probe  2 , and a control device  10  electrically connected to the ultrasonic probe  2  via a cable  3 . 
     The ultrasonic measurement apparatus  1  transmits an ultrasonic wave from the ultrasonic probe  2  to the inside of a living body (e.g., a human body) in the state in which the ultrasonic probe  2  has contact with a surface of the living body. Further, the ultrasonic measurement apparatus  1  receives the ultrasonic wave reflected by an organ in the living body using the ultrasonic probe  2  to, for example, obtain an internal tomographic image of the inside of the living body, or measure the state (e.g., blood flow) of the organ in the living body based on the received signal. 
     1. Configuration of Control Device 
     As shown in  FIG. 1 , for example, the control device  10  corresponds to a controller, and is provided with an operating interface  11  including buttons or a touch panel, and a display  12 . Further, although not shown in the drawings, the control device  10  is provided with a storage section formed of a memory or the like, and an arithmetic section constituted by a central processing unit (CPU). The control device  10  makes the arithmetic section execute a variety of programs stored in the storage section to thereby control the ultrasonic measurement apparatus  1 . For example, the control device  10  outputs a command for controlling the drive of the ultrasonic probe  2 , forms an image of the internal structure of the living body and then makes the display  12  display the image, and measures the living body information such as the blood flow to make the display  12  display the living body information based on the received signal input from the ultrasonic probe  2 . As such a control device  10 , there can be used a terminal device such as a tablet terminal, a smartphone, or a personal computer, and a dedicated terminal device for operating the ultrasonic probe  2  can also be used. 
     2. Configuration of Ultrasonic Probe 
       FIG. 2  is a cross-sectional view showing a schematic configuration of the ultrasonic probe  2 . 
     As shown in  FIG. 2 , the ultrasonic probe  2  is provided with a housing  21 , an ultrasonic device  22  housed inside the housing  21 , and a circuit board  23  provided with a driver circuit for controlling the ultrasonic device  22 . It should be noted that the ultrasonic device  22  and the circuit board  23  constitute an ultrasonic sensor  24 . 
     2-1. Configuration of Housing 
     As shown in  FIG. 1 , the housing  21  is formed to have a box-like shape having, for example, a rectangular planar shape, and on one surface (a sensor surface  21 A) perpendicular to the thickness direction, there is disposed a sensor window  21 B, and a part of the ultrasonic device  22  is exposed therefrom. Further, through a part (a side surface in the example shown in  FIG. 1 ) of the housing  21 , there is inserted the cable  3  connected to the circuit board  23  located inside the housing  21 , and the ultrasonic probe  2  and the control device  10  are connected by the cable  3 . It should be noted that the connection configuration between the ultrasonic probe  2  and the control device  10  is not limited thereto, but the ultrasonic probe  2  and the control device  10  are connected to each other with wireless communication, and further, a variety of constituents of the control device  10  can also be disposed inside the ultrasonic probe  2 . 
     2-2. Configuration of Circuit Board 
     The circuit board  23  is electrically connected to signal terminals  51 P (see  FIG. 3 ) and common terminals  52 P (see  FIG. 3 ) of the ultrasonic device  22  described later to control the ultrasonic device  22  based on the control by the control device  10 . 
     Specifically, the circuit board  23  is provided with a transmission circuit, a reception circuit. The transmission circuit outputs a drive signal for making the ultrasonic device  22  perform ultrasonic transmission. The reception circuit obtains a reception signal output from the ultrasonic device  22 , which has received the ultrasonic wave, then performs an amplification process, an A-D conversion process, a phasing addition process of the reception signal, and then outputs the result to the control device  10 . 
     2-3. Configuration of Ultrasonic Device 
       FIG. 3  is a plan view of a part of an element substrate  41  constituting the ultrasonic device  22  viewed from a sealing plate  42  side.  FIG. 4  is a cross-sectional view of the ultrasonic device  22  cut along the line A-A shown in  FIG. 3 . It should be noted that in  FIG. 3 , the number of ultrasonic transducers Tr arranged is reduced for the sake of convenience of explanation, but in reality, there are arranged a larger number of ultrasonic transducers Tr. 
     As shown in  FIG. 2  and  FIG. 4 , the ultrasonic device  22  is provided with the element substrate  41 , the sealing plate  42  (a substrate), and an acoustic lens  44 . 
     As shown in  FIG. 3 , the ultrasonic device  22  is provided with a plurality of ultrasonic transducers Tr arranged in a two-dimensional array along the X direction (a scanning direction) and the Y direction (a slicing direction) crossing each other (perpendicular to each other as an example in the present embodiment). In the present embodiment, 1-CH (channel) transmission/reception column Ch is constituted by a plurality of ultrasonic transducers Tr arranged in the Y direction. Further, a plurality of the 1-CH transmission/reception columns Ch arranged side by side along the X direction constitutes the ultrasonic device  22  having a one-dimensional array structure. Here, an area where the ultrasonic transducers Tr are arranged is defined as an array area Ar 1 . 
     2-3-1. Configuration of Element Substrate 
     As shown in  FIG. 4 , the element substrate  41  is provided with a substrate main body  411 , and a vibrating film  412  disposed on the sealing plate  42  side (−Z side) of the substrate main body  411 . Further, the vibrating film  412  is provided with a plurality of piezoelectric elements  5 . 
     The substrate main body  411  is a substrate for supporting the vibrating film  412 , and is formed of a semiconductor substrate made of, for example, Si. To the substrate main body  411 , there are provided apertures  411 A corresponding respectively to the ultrasonic transducers Tr. 
     In the present embodiment, each of the apertures  411 A is a through hole penetrating the substrate main body  411  in the thickness direction thereof, and the vibrating film  412  is disposed so as to close one end side (the sealing plate  42  side) of the through hole. 
     The vibrating film  412  is formed of, for example, SiO 2  or a stacked body of SiO 2  and ZrO 2 , and is disposed on the sealing plate  42  side of the substrate main body  411 . The thickness dimension of the vibrating film  412  is small with respect to that of the substrate main body  411 . The vibrating film  412  is supported by partition walls  411 B constituting the aperture  411 A, and closes the sealing plate  42  side of the aperture  411 A. A part of the vibrating film  412  overlapping the aperture  411 A in the plan view constitutes a flexible membrane  412 A. In other words, the aperture  411 A defines the outer edge of the flexible membrane  412 A as a vibrating area of the vibrating film  412 . 
     On the surface on the sealing plate  42  side of the flexible membrane  412 A, there is disposed the piezoelectric element  5 . It should be noted that although described later in detail, the piezoelectric element  5  is configured as a stacked body having a lower electrode  51 , a piezoelectric film  6 , and an upper electrode  52  stacked on one another in sequence. The flexible membrane  412 A corresponds to a driver driven by the piezoelectric element  5 , and the flexible membrane  412 A and the piezoelectric element  5  constitute the ultrasonic transducer Tr as a piezoelectric actuator. 
     In such an ultrasonic transducer Tr, by applying a pulse-wave voltage having a predetermined frequency between the lower electrode  51  and the upper electrode  52 , the flexible membrane  412 A of the vibrating film  412  in an opening region of the aperture  411 A is vibrated to transmit the ultrasonic wave from the aperture  411 A side. Further, when the flexible membrane  412 A is vibrated by the ultrasonic wave reflected by an object and entering the ultrasonic transducer Tr through the aperture  411 A, a potential difference occurs between an upper part and a lower part of the piezoelectric film  6 . Therefore, by detecting the electrical potential difference occurring between the lower electrode  51  and the upper electrode  52 , the ultrasonic wave is detected, namely received. 
     Here, as shown in  FIG. 3 , the lower electrode  51  corresponds to a first electrode layer, and is formed linearly along the Y direction to constitute the 1-CH transmission/reception column Ch. Both end parts (the ±Y side end parts) of the lower electrode  51  extend to terminal areas Ar 2  (the terminal area Ar 2  on the −Y side is illustrated alone in  FIG. 3 ) disposed on the ±Y side of the array area Ar 1 . Further, the tip of the lower electrode  51  in the terminal area Ar 2  constitutes the signal terminal  51 P to be electrically connected to the circuit board  23 . 
     Further, the upper electrode  52  corresponds to a second electrode layer, and is formed to have a linear shape along the X direction. The ±X side end parts of the upper electrode  52  are respectively connected to common electrode lines  52 S. The common electrode lines  52 S each connect the upper electrodes  52  arranged along the Y direction to each other. Further, both end parts (±Y side end parts) of the common electrode line  52 S are connected in the respective terminal areas Ar 2  to the respective common terminals  52 P to be electrically connected to the circuit board  23 . The common terminals  52 P are connected to, for example, a reference electrical potential circuit (not shown) of the circuit board  23 , and are set to the reference electrical potential. 
     It should be noted that a detailed description of the piezoelectric element  5  will be described later. 
     2-3-2. Configuration of Sealing Plate 
     The sealing plate  42  shown in  FIG. 2  and  FIG. 4  is formed to have the same planar shape when viewed from the thickness direction as that of, for example, the element substrate  41 , and is formed of a semiconductor substrate made of Si or the like, or an insulator substrate. It should be noted that the material and the thickness of the sealing plate  42  affect the frequency characteristics of the ultrasonic transducer Tr, and are therefore preferably set based on the central frequency of the ultrasonic wave transmitted/received by the ultrasonic transducer Tr. 
     The sealing plate  42  has a plurality of concave grooves  421  (see  FIG. 4 ), which correspond to the apertures  411 A, in an area opposed to the array area Ar 1  of the element substrate  41 . Thus, it results that a gap having a predetermined dimension is provided between the element substrate  41  and the area (inside the aperture  411 A) where the flexible membrane  412 A is formed out of the vibrating film  412 , and thus, the vibration of the vibrating film  412  is prevented from being hindered. Further, the problem (cross talk) that the back wave from one ultrasonic transducer Tr enters another adjacent ultrasonic transducer Tr can be prevented from occurring. 
     Further, the sealing plate  42  is provided with a connecting section for connecting the terminals  51 P,  52 P to the circuit board  23  disposed at a position opposed to the terminal area Ar 2  of the element substrate  41 . As the connecting section, there is a configuration including, for example, an aperture provided to the element substrate  41 , and a wiring member such as flexible printed circuits (FPC), cable lines, or wires for connecting the terminals  51 P,  52 P and the circuit board  23  to each other via the aperture. 
     2-3-3. Configuration of Acoustic Layer and Acoustic Lens 
     As shown in  FIG. 4 , the acoustic matching layer  43  is disposed on an opposite side to the sealing plate  42  of the element substrate  41 , and fills the aperture  411 A. 
     The acoustic lens  44  is disposed on the opposite side to the sealing plate  42  of the element substrate  41 , namely the +Z side of the element substrate  41  and the acoustic layer  43 . The acoustic lens  44  is applied to the living body surface, and converges the ultrasonic wave inside the living body, wherein the ultrasonic wave has been transmitted from the ultrasonic transducer Tr. Further, the acoustic lens  44  makes the ultrasonic wave having been reflected inside the living body propagate to the ultrasonic transducer Tr via the acoustic layer  43 . 
     2-3-4. Configuration of Piezoelectric Element 
     Next, the configuration of the piezoelectric element  5  will be described in more detail. 
       FIG. 5  is a plan view of the ultrasonic transducer Tr provided to the element substrate  41  viewed from the sealing plate  42  side.  FIG. 6  is a cross-sectional view of a part of the ultrasonic transducer Tr cut along the line B-B shown in  FIG. 5 . 
     As described above, the piezoelectric element  5  is provided with the lower electrode  51 , the piezoelectric film  6 , and the upper electrode  52 , and among these constituents, a part (columnar stack) where the lower electrode  51 , the piezoelectric film  6 , and the upper electrode  52  overlap each other in the plan view viewed from the stacking direction constitutes an active section  50 . The active section  50  is a part which deforms due to voltage application to the lower electrode  51  and the upper electrode  52 , and is located on the flexible membrane  412 A to constitute the ultrasonic transducer Tr. 
     The piezoelectric film  6  corresponds to the piezoelectric layer, and is formed using, for example, a transition metal oxide having a perovskite structure, specifically, lead zirconate titanate including Pb, Ti, and Zr. 
     The piezoelectric film  6  has, for example, a roughly rectangular outer shape, and is disposed at a position where the piezoelectric film  6  overlaps the flexible membrane  412 A so as to cover a part of the lower electrode  51  in the plan view. The piezoelectric film  6  has a piezoelectric main body  61  and a piezoelectric outer periphery  62 . 
     As shown in  FIG. 5 , the piezoelectric main body  61  is a part overlapping both of the lower electrode  51  and the upper electrode  52  (except a connection electrode part  523  described later), and constitutes the active section  50 . 
     In the plan view, the piezoelectric outer periphery  62  is a part that is continuous with the outside of the piezoelectric main body  61 but does not overlap either or both of the lower electrode  51  and the upper electrode (except the connection electrode part  523  described later). 
     The lower electrode  51  corresponds to the first electrode layer, and is formed of a metal material such as Pt, Ir, Ti, Zr, Au, Ni, NiCr, TiW, Al, or Cu. As shown in  FIG. 5 , the lower electrode  51  is provided with lower electrode main bodies  511  and lower electrode connection parts  512 . 
     The lower electrode main body  511  corresponds to a first part, and overlaps the piezoelectric film  6  in the plan view. A part of the lower electrode main body  511  overlapping the piezoelectric film  6  (a piezoelectric main body  61 ) and the upper electrode  52  (an upper electrode main body  521 ) constitutes the active section  50 . 
     The lower electrode connection parts  512  each correspond to a second part, and are parts respectively extending along the Y direction from the ±Y sides of the lower electrode main body  511  and not overlapping the piezoelectric film  6 . The lower electrode connection parts  512  each connect the adjacent lower electrode main bodies  511  of the plurality of ultrasonic transducers Tr to each other, wherein the plurality of ultrasonic transducers Tr is included in the transmission/reception column Ch. 
     The upper electrode  52  corresponds to the second electrode layer, and is formed of a metal material such as Pt, Ir, Ti, Zr, Au, Ni, NiCr, TiW, Al, or Cu. As shown in  FIG. 5 , the upper electrode  52  is provided with upper electrode main bodies  521 , upper electrode connection parts  522 , and connection electrode parts  523 . 
     The upper electrode main body  521  corresponds to a third part, and overlaps the lower electrode main body  511  and the piezoelectric main body  61  in the plan view to constitute the active section  50 . 
     The upper electrode connection part  522  continuously extends along the X direction from each of the ±X sides of the upper electrode main body  521  to connect the adjacent upper electrode main bodies  521  to each other in the X direction. In the present embodiment, end edges  521 A on the ±Y sides of the upper electrode main body  521  and end edges  522 A on the ±Y sides of the upper electrode connection part  522  continue along a straight line. 
     The connection electrode part  523  corresponds to a fourth part, and is disposed continuously from each of the ±Y sides of the piezoelectric outer periphery  62  of the piezoelectric film  6  to the lower electrode connection part  512 . Further, as shown in  FIG. 3 , it is also possible for the connection electrode part  523  to be disposed continuously between the piezoelectric outer peripheries  62  of the ultrasonic transducers Tr adjacent to each other in the Y direction. 
     Here, an end edge  523 A on the −Y side of the connection electrode part  523  disposed on the +Y side is displaced toward the +Y side as much as a predetermined dimension from the end edges  521 A,  522 A on the +Y side of the upper electrode main body  521  and the upper electrode connection part  522 . Further, the end edge  523 A on the +Y side of the connection electrode part  523  disposed on the −Y side is displaced toward the −Y side as much as a predetermined dimension from the end edges  521 A,  522 A on the −Y side of the upper electrode main body  521  and the upper electrode connection part  522 . In other words, the connection electrode part  523  is disposed separately from the upper electrode main body  521  and the upper electrode connection part  522 . 
       FIG. 7  and  FIG. 8  are each a diagram showing an example of a vicinity of a boundary between the lower electrode main body  511  and a lower electrode connection part formed on the vibrating film  412 . 
     Incidentally, in the present embodiment, between the lower electrode main body  511  and the lower electrode connection part  512 , there is provided a shape including at least a part where the lower electrode main body  511  and the lower electrode connection part  512  are separated from each other as shown in  FIG. 7  and  FIG. 8 . 
     That is, the piezoelectric element  5  according to the present embodiment is manufactured by forming the lower electrode  51 , then depositing the piezoelectric layer  60  (see  FIG. 10 ) for forming the piezoelectric film  6 , and then patterning the piezoelectric layer  60  by dry etching (ion milling). 
     As such, if the piezoelectric layer  60  remains in positions other than the formation position of the ultrasonic transducer Tr, there is a possibility that the performance of the ultrasonic device  22  deteriorates. For example, if the piezoelectric layer  60  remains on the flexible membrane  412 A at a position other than the ultrasonic transducer Tr, the stress balance of the flexible membrane  412 A is lost to affect the frequency and the acoustic pressure of the ultrasonic waves which can be transmitted or received. Therefore, it is necessary to perform the etching process taking a sufficiently long time so that the piezoelectric layer  60  does not remain other positions than the position where the ultrasonic transducer Tr is formed. However, in the outer edge (an edge part) of the piezoelectric film  6 , the etching rate increases to a higher rate compared to those in other positions, and thus, the connection part between the lower electrode connection part  512  and the lower electrode main body  511  is over-etched. 
     Therefore, as shown in  FIG. 7 , on the lower electrode main body  511  side of the lower electrode connection part  512 , there is provided the shape having at least a part separated from the lower electrode main body  511  (there is formed a void  512 A). Further, if the over-etching is advanced, there is provided a shape of separating the lower electrode main body  511  and the lower electrode connection part  512  from each other as shown in, for example,  FIG. 8  in some cases. If a shape such as shown in  7  is provided, the electrical resistance of the lower electrode connection part  512  increases to fail to input an appropriate signal to the lower electrode main body  511 , and further, if a shape such as shown in  FIG. 8  is provided, breaking occurs between the lower electrode main body  511  and the lower electrode connection part  512 . 
     It should be noted that breaking in the invention is not limited to the shape in which the lower electrode connection part  512  is separated from the lower electrode main body  511  as shown in  FIG. 8 , but includes a shape in which a part of the lower electrode connection part  512  is separated from the lower main body  511  as shown in  FIG. 7 . 
     In contrast, in the present embodiment, as shown in  FIG. 6 , the connection electrode part  523  of the upper electrode  52  is disposed in the void  512 A to have contact with both of the lower electrode main body  511  and the lower electrode connection part  512 . Specifically, the separated part between the lower electrode main body  511  and the lower electrode connection part  512  formed in the void  512 A is filled with the connection electrode part  523 . 
     Thus, in the present embodiment, the piezoelectric layer  60  for forming the piezoelectric film  6  does not remain in any areas other than the ultrasonic transducers Tr, and at the same time, an increase in electrical resistance and breaking in the void  512 A between the lower electrode main body  511  and the lower electrode connection part  512  are prevented. 
     2-3-5. Method of Manufacturing Piezoelectric Element 
     Next, a method of manufacturing a piezoelectric element  5  such as described above will be described. 
       FIG. 9  is a flowchart showing the method of manufacturing the piezoelectric element  5 , and  FIG. 10  is a diagram showing the manufacturing process of the piezoelectric element  5  in the respective steps of  FIG. 9 . 
     In order to manufacture the piezoelectric element  5 , firstly, the lower electrode is formed (step S 1 ). In the step S 1 , the lower electrode layer is deposited on the vibrating film  412  of the element substrate  41  provided with the vibrating film  412  using an electrode material constituting the lower electrode  51 . Then, the lower electrode layer is patterned by etching to form the lower electrode  51  as shown in the first part of  FIG. 10 . 
     Then, the piezoelectric layer deposition is formed (step S 2 ). In the step S 2 , as shown in the second part of  FIG. 10 , the piezoelectric layer  60  (PZT) covering the lower electrode  51  is formed on the vibrating film  412 . In the formation of the piezoelectric layer  60 , a coating process for applying a PZT solution on the vibrating film  412  and a calcination process for calcining the PZT solution thus applied are performed a plurality of times using, for example, a solution growth technique to form the piezoelectric layer  60  having a predetermined thickness. 
     Subsequently, the piezoelectric layer  60  is etched to be patterned (step S 3 ) into a predetermined shape. In the step S 3 , the piezoelectric layer  60  is etched using dry etching (ion milling) to form the piezoelectric film  6  as shown in the third part of  FIG. 10 . As such, over-etching is advanced along the edge part of the piezoelectric film  6 , and thus, a void  512 A such as shown in  FIG. 7  and  FIG. 8  is formed on the lower electrode main body  511  side of the lower electrode connection part  512 . 
     Then, there is deposited (step S 4 ) an upper electrode layer  520  made of an electrode material for forming the upper electrode  52 . In the step S 4 , the upper electrode layer  520  covering the lower electrode  51  and the piezoelectric film  6  is formed on the vibrating film  412  by, for example, sputtering. As such, as shown in the fourth part of  FIG. 10 , the upper electrode layer  520  is disposed in the void  512 A formed in the step S 3  (it can also be said that the void  512 A is filled with the upper electrode layer  520 ). 
     Subsequently, the upper electrode layer  520  is etched to be patterned (step S 5 ) into the upper electrode  52 . Thus, as shown in the fifth part of  FIG. 10 , the connection electrode part  523  is formed at a position separated from the upper electrode main body  521  and the upper electrode connection part  522 . Since the void  512 A is filled with the connection electrode part  523 , the lower electrode main body  511  and the lower electrode connection part  512  of the lower electrode  51  are connected to each other by the connection electrode part  523 , and thus, the lower electrode main body  511  and the lower electrode connection part  512  are electrically connected to each other. 
     It should be noted that in the case of manufacturing the ultrasonic transducer Tr, an etching process is subsequently performed on the element substrate  41  from the surface on the opposite side to the vibrating film  412  to form the aperture  411 A. 
     Functions and Advantages of Present Embodiment 
     In the present embodiment, the lower electrode  51  constituting the piezoelectric elements  5  has the lower electrode main bodies  511  each overlapping the piezoelectric film  6  in the plan view, and the lower electrode connection parts  512  not overlapping the piezoelectric film  6 . The void  512 A is formed on the lower electrode main body  511  side of the lower electrode connection part  512 , and thus, the lower electrode connection part  512  is partially separated from the lower electrode main body  511 . Meanwhile, the upper electrode  52  constituting the piezoelectric elements  5  is configured including the upper electrode main bodies  521  each overlapping the lower electrode main body  511  and the piezoelectric main body  61  to constitute the active section  50 , and a connection electrode part  523  disposed separately from the upper electrode main bodies  521 . The connection electrode part  523  is formed continuously from the piezoelectric outer periphery  62  of the piezoelectric film  6  to the lower electrode connection part  512 , and has contact with the lower electrode main body  511  and the lower electrode connection part  512 . 
     Therefore, it results that the connection electrode part  523  electrically connects the lower electrode main body  511  and the lower electrode connection part  512  to each other, and thus, it is possible to prevent the problem that breaking occurs between the lower electrode main body  511  and the lower electrode connection part  512 . Therefore, it is possible to appropriately input a drive signal to the lower electrode main body  511  constituting the active section  50  from the lower electrode connection part  512 , and thus, the reliability of the piezoelectric element  5  can be enhanced. Thus, it is also possible to enhance the equipment reliability in the ultrasonic transducer Tr, the ultrasonic probe  2 , and the ultrasonic measurement apparatus  1  equipped with the piezoelectric element  5 . 
     Further, since the connection electrode part  523  is disposed so as to fill in the void between the lower electrode main body  511  and the lower electrode connection part  512 , breaking between the lower electrode main body  511  and the lower electrode connection part  512  can more surely be prevented, and thus, the reliability of the piezoelectric element  5  can be made higher. 
     In the present embodiment, the connection electrode part  523  can be made concurrently with the upper electrode main bodies  521  and the upper electrode connection part  522  by etching the upper electrode layer  520  in the step S 5 , and thus, the manufacturing efficiency can also be improved. 
     Second Embodiment 
     Hereinafter, a second embodiment of the invention will be described. 
     In the piezoelectric element  5  according to the first embodiment, the connection electrode part  523  as a part of the upper electrode  52  is formed in the step S 5  at a position separated from the upper electrode main body  521 , and the lower electrode main body  511  and the lower electrode connection part  512  are electrically connected to each other by the connection electrode part  523 . In contrast, the second embodiment is different from the first embodiment described above in the point that the lower electrode main body  511  and the lower electrode connection part  512  are electrically connected by an electrode different from the upper electrode  52 . It should be noted that in the following description, the constituents having already been described are denoted by the same reference symbols, and the description thereof will be omitted or simplified. 
       FIG. 11  is a cross-sectional view showing an example of an ultrasonic transducer Tr according to the second embodiment. 
     Similarly to the first embodiment, the ultrasonic transducer Tr of the present embodiment is constituted by the flexible membrane  412 A as the driver, and the piezoelectric element  5 . The piezoelectric element  5  according to the present embodiment is formed by stacking the lower electrode  51 , the piezoelectric film  6 , and the upper electrode  52  on one another in sequence. 
     Here, the lower electrode  51  is formed of the lower electrode main bodies  511  and the lower electrode connection parts  512 . Similarly to the first embodiment, the lower electrode connection part  512  is at least partially separated from the lower electrode main body  511 , and the void  512 A is formed on the lower electrode main body  511  side. 
     In the present embodiment, the lower electrode main body  511  corresponds to the first electrode layer, and the lower electrode connection part  512  corresponds to a first conductive layer. Similarly to the first embodiment, the lower electrode connection parts  512  are formed in the step S 1  concurrently with the lower electrode main body  511 . Further, when patterning the piezoelectric film  6  in the step S 3 , the end part on the lower electrode main body  511  side of the lower electrode connection part  512  is over-etched, and thus, the lower electrode connection part  512  is separated from the lower electrode main body  511  to form the void  512 A. 
     The upper electrode  52  is provided with the upper electrode main body  521  and the upper electrode connection part  522 . The upper electrode main body  521  corresponds to the second electrode layer in the present embodiment. The configuration of the upper electrode main body  521  and the upper electrode connection part  522  is the same as in the first embodiment described above. 
     Further, in the present embodiment, there is separately provided a connection electrode  53  as the second conductive layer independently of the upper electrode  52  described above. The connection electrode  53  is formed of, for example, the same electrode material as that of the upper electrode  52  continuously from the piezoelectric outer periphery  62  of the piezoelectric film  6  to the lower electrode connection part  512 . Further, the connection electrode  53  is disposed in the void  512 A of the lower electrode connection part  512  to have contact with the lower electrode main body  511  and the lower electrode connection part  512 . 
     It should be noted that it is also possible for the connection electrode  53  to be disposed continuously between the piezoelectric outer peripheries  62  of the ultrasonic transducers Tr adjacent in the Y direction to each other so as to cover the lower electrode connection part  512  disposed between those ultrasonic transducers Tr similarly to the connection electrode part  523  in the first embodiment. 
     Further, in the present embodiment, the connection electrode  53  is formed to have larger thickness dimension compared to the upper electrode  52 . In such a configuration, since the thickness dimension of the upper electrode  52  overlapping the active section  50  is reduced to increase the displacement of the active section  50 , the transmission/reception sensitivity of the ultrasonic transducer Tr can be improved. Further, the thickness dimension of the connection electrode  53  is increased, to thereby make it possible to reduce the electrical resistance of the lower electrode connection part  512 , and thus the voltage drop of the drive signal input to the lower electrode main body  511  can be suppressed. 
       FIG. 12  is a flowchart showing a method of manufacturing the piezoelectric element  5  according to the second embodiment. 
     The piezoelectric element  5  according to the second embodiment can be manufactured by roughly the same manufacturing method as in the first embodiment. Specifically, in the present embodiment, as shown in  FIG. 12 , firstly, the lower electrode  51  including the lower electrode main body  511  and the lower electrode connection part  512  is formed on the vibrating film  412  in the step S 1 . 
     Then, in the step S 2 , the piezoelectric layer  60  covering the lower electrode  51  is deposited on the vibrating film  412 . Then, in the step S 3 , the piezoelectric layer  60  is etched to form the piezoelectric film  6  as shown in the third part of  FIG. 10 . As such, similarly to the first embodiment described above, over-etching is advanced along the edge part of the piezoelectric film  6 , and thus, a void  512 A such as shown in  FIG. 7  and  FIG. 8  is formed on the lower electrode main body  511  side of the lower electrode connection part  512 . 
     Subsequently, the step S 4  is performed to deposit the upper electrode layer  520  for forming the upper electrode  52 . As such, the upper electrode layer  520  is deposited in accordance with the film thickness dimension of the upper electrode  52 . 
       FIG. 13  is a diagram showing the manufacturing process of the piezoelectric element  5  on and after the step S 11  of  FIG. 12 . 
     Subsequently, patterning using etching is performed on the upper electrode layer  520  to form (step S 11 ) the upper electrode  52  having the upper electrode main body  521  and the upper electrode connection part  522  as shown in the first part of  FIG. 13 . In the step S 11 , the lower electrode connection part  512  is at least partially separated from the lower electrode main body  511  in the void  512 A. 
     Further, in the present embodiment, after the step S 11 , the electrode layer  530  is further deposited (step S 12 ) on the vibrating film  412  using the same electrode material as that of the upper electrode  52  as shown in the second part of  FIG. 13 . As such, the electrode layer  530  is deposited with larger film thickness dimension than that of the upper electrode  52 . 
     Subsequently, patterning using etching is performed on the electrode layer  530  to form (step S 13 ) the connection electrode  53  as shown in the third part of  FIG. 13 . By providing the connection electrode  53  to the void  512 A, it becomes possible for the lower electrode main body  511  and the lower electrode connection part  512  to be electrically connected via the connection electrode  53 . 
     Functions and Advantages of Present Embodiment 
     In the piezoelectric element  5  according to the present embodiment, the void  512 A is formed on the lower electrode main body  511  side of the lower electrode connection part  512 , and thus, a part of the lower electrode connection part  512  is separated from the lower electrode main body  511 . Further, the connection electrode  53  independent of the upper electrode  52  is disposed separately from the upper electrode  52  (the upper electrode main body  521 ) constituting the active section  50  of the piezoelectric element  5 , and the connection electrode  53  is continuously formed from the piezoelectric outer periphery  62  of the piezoelectric film  6  to the lower electrode connection part  512  to have contact with the lower electrode main body  511  and the lower electrode connection part  512 . 
     Therefore, it results that the connection electrode  53  electrically connects the lower electrode main body  511  and the lower electrode connection part  512  to each other, and thus, it is possible to prevent the problem that breaking occurs between the lower electrode main body  511  and the lower electrode connection part  512 . Therefore, it is possible to appropriately input a drive signal to the lower electrode main body  511  constituting the active section  50  from the lower electrode connection part  512 , and thus, the reliability of the piezoelectric element  5  can be enhanced. 
     Further, since the connection electrode  53  is disposed in the void between the lower electrode main body  511  and the lower electrode connection part  512 , breaking between the lower electrode main body  511  and the lower electrode connection part  512  can be prevented, and thus, the reliability of the piezoelectric element can be made higher. 
     Further, in the present embodiment, the connection electrode  53  is formed to be larger in thickness dimension than the upper electrode  52 . Therefore, the electrical resistance of the lower electrode connection part  512  covered with the connection electrode  53  is reduced, and thus, it is possible to suppress the influence such as the voltage drop in the drive signal input to the lower electrode main body  511  from the lower electrode connection part  512 . Further, since the thickness dimension of the upper electrode  52  can be decreased, the thickness dimension of the active section  50  can also be decreased accordingly to thereby increase the displacement of the active section  50 . Therefore, the transmission/reception sensitivity to the ultrasonic wave in the ultrasonic transducer Tr can be improved. 
     Third Embodiment 
     Next, a third embodiment of the invention will be described. 
     In the first embodiment described above, there is illustrated the configuration of the ultrasonic probe  2  having the ultrasonic device  22  equipped with the piezoelectric element  5  housed in the housing  21 , and the ultrasonic measurement apparatus  1  equipped with the ultrasonic probe  2  to perform ultrasonic measurement. In contrast, it is also possible for the piezoelectric element and the piezoelectric actuator equipped with the piezoelectric element  5  to be applied to other electronic apparatuses, and in the third embodiment, there will be described a liquid jet apparatus as an example of such other electronic apparatuses. 
       FIG. 14  is a diagram showing a configuration example of an appearance of a printer  100  as an application example of a recording apparatus equipped with the piezoelectric element according to the invention.  FIG. 15  is an exploded perspective view schematically showing the recording head  70  provided to the printer  100 . 
     The printer  100  corresponds to the liquid jet apparatus, and is provided with a supply unit  110  for supplying a medium, a conveying unit  120  for conveying the medium, a carriage  130  attached with a recording head  70 , a carriage moving unit  140  for moving the carriage  130 , a control unit (not shown) for controlling the printer  100  as shown in  FIG. 14 . The printer  100  controls the units  110 ,  120 , and  140  and the carriage  130  based on print data input from external equipment such as a personal computer to print an image on the medium M. 
     The supply unit  110  supplies the medium M at an image formation position. For example, the supply unit  110  is provided with a roll body  111  around which the medium M is wound, a roll driving motor (not shown), and a roll driving gear train (not shown). Further, based on a command from the control unit, the roll driving motor is rotationally driven, and the rotational force of the roll driving motor is transmitted to the roll body  111  via the roll driving gear train. Thus, the roll body  111  rotates, and a paper sheet wound around the roll body  111  is supplied on the downstream side (+β side) in the β direction (a sub-scanning direction). 
     The conveying unit  120  conveys the medium M supplied from the supply unit  110  along the β direction. For example, the conveying unit  120  is provided with a conveying roller  121 , a driven roller (not shown) disposed across the medium M from the conveying roller  121  to be driven by the conveying roller  121 , and a platen  122  disposed on the downstream side in the β direction of the conveying roller  121 . The driving force from the roll driving motor not shown is transmitted to the conveying roller  121 , and when the roll driving motor is driven by the control of the control unit (not shown), the conveying roller  121  is rotationally driven by the rotational force, and the conveying roller  121  conveys the medium M along the β direction in the state of sandwiching the medium M between the driven roller and the conveying roller  121 . 
     The carriage  130  carries the recording head  70  for printing the image on the medium M. The recording head  70  is connected to the control unit via a cable  131 . The recording head  70  will be described later. The carriage  130  is disposed so as to be movable along an α direction (a main scanning direction) crossing the β direction due to the carriage moving unit  140 . 
     The carriage moving unit  140  reciprocates the carriage  130  along the α direction. For example, the carriage moving unit  140  is provided with a carriage guide shaft  141 , a carriage motor  142 , and a timing belt  143 . The carriage guide shaft  141  is disposed along the α direction, and both end parts of the carriage guide shaft  141  are fixed to the housing of the printer  100 . The carriage motor  142  drives the timing belt  143 . The timing belt  143  is supported roughly in parallel to the carriage guide shaft  141 , and a part of the carriage  130  is fixed to the timing belt  143 . When the carriage motor  142  is driven based on the command of the control unit, the timing belt  143  is made to run forward and backward, and the carriage  130  fixed to the timing belt  143  reciprocates while being guided by the carriage guide shaft  141 . 
     The recording head  70  corresponds to the liquid jet head, and ejects ink supplied from an ink tank (not shown) toward a γ direction crossing the α direction and the β direction to form the image on the medium M. As shown in  FIG. 15 , the recording head  70  is provided with a pressure chamber forming substrate  71 , a nozzle plate  72 , an actuator unit  73 , and a sealing plate  74 . 
     The pressure chamber forming substrate  71  is a plate member formed of, for example, a silicon single-crystal substrate. The pressure chamber forming substrate  71  is provided with a plurality of pressure chambers  711 , ink supply channels  711  for supplying these pressure chambers  712  with the ink, and a communication part  712  communicated with each of the pressure chambers  711  via the respective ink supply channels  713 . 
     The plurality of pressure chambers  711  is disposed so as to correspond one-to-one to the nozzles  721  constituting a nozzle row provided to the nozzle plate  72  as described later. Specifically, the pressure chambers  711  are formed along the nozzle row direction at the same pitch as the formation pitch of the nozzles  721 . 
     The communication part  713  is formed along the plurality of pressure chambers  711 . The communication part  713  is communicated with a communication aperture part  731  of the vibrating plate  734  described later and a liquid chamber space part  742  of the sealing plate  74 , and is filled with the ink supplied from the ink tank (not shown). The ink with which the communication part  713  is filled is supplied to the pressure chambers  712  via the ink supply channels  711 . In other words, the communication part  713  constitutes a reservoir (a common liquid chamber) as an ink chamber common to the pressure chambers  711 . 
     It should be noted that the ink supply channels  712  are each a part formed to have the width narrower than that of the pressure chamber  711  to function as a flow pass resistance with respect to the ink flowing from the communication part  713  into the pressure chamber  711 . 
     The nozzle plate  72  is provided with the nozzle row constituted by the plurality of nozzles  721 , and is bonded to one surface (a surface on the opposite side to the actuator unit  73 ) of the pressure chamber forming substrate  71 . The plurality of nozzles  721  is formed at the pitch corresponding to the dot formation density (e.g., 300 dpi). It should be noted that the nozzle plate  72  is formed of, for example, glass ceramics, a silicon single-crystal substrate, or stainless steel. 
     The actuator unit  73  is configured including the vibrating plate  731  (the driver) disposed on the opposite side to the nozzle plate  72  of the pressure chamber forming substrate  71 , and the piezoelectric elements  5  stacked on the vibrating plate  731 . 
     The vibrating plate  731  includes an elastic film  732  formed on the pressure chamber forming substrate  71 , and an insulator film  732  formed on the elastic film  733 . It should be noted that as the elastic film  732 , there is preferably used, for example, silicon dioxide (SiO 2 ) having the thickness of 300 through 2000 nm. Further, as the insulator film  733 , there is preferably used, for example, zirconium oxide (ZrO x ) having the thickness of 30 through 600 nm. The area for blocking the pressure camber  711  of the vibrating plate  731  is an area (a flexible part) allowed to make a distortional deformation in the direction of coming closer to and getting away from the nozzle  721  due to the drive of the piezoelectric element  5 . It should be noted that the part corresponding to the communication part  713  of the pressure chamber forming substrate  71  in the vibrating plate  731  is provided with a communication aperture part  734  communicated with the communication part  713 . 
     The piezoelectric elements  5  each have substantially the same configuration as that in the first embodiment or the second embodiment described above. The piezoelectric element  5  is disposed at the position corresponding to the pressure chamber  711  to constitute the piezoelectric actuator together with the flexible part as the area blocking the pressure chamber  711  of the vibrating plate  731 . It should be noted that although not shown in the drawings, the lower electrode  51  and the upper electrode  52  are connected to the electrode terminals formed in the terminal area using leading electrodes  735 . 
     It should be noted that although in  FIG. 15 , there is illustrated the configuration in which a groove part connecting non-coated parts of the plurality of piezoelectric elements  5  disposed along one direction is formed, this is not a limitation, and it is also possible to provide groove parts individually to the piezoelectric elements  5 . 
     The sealing plate  74  is bonded to the surface on the opposite side to the pressure chamber forming substrate  71  of the actuator unit  73 . On the surface located on the actuator unit  73  side of the sealing plate  74 , there is formed a housing space part  741  capable of housing the piezoelectric elements  5 . Further, in an area corresponding to the communication aperture  734  and the communication part  713  of the sealing plate  74 , there is disposed the liquid chamber space part  742 . The liquid chamber space part  742  is communicated with the communication aperture  734  and the communication part  713  to constitute the reservoir functioning as the ink chamber common to the pressure chambers  711 . It should be noted that although not shown in the drawings, the sealing plate  74  is provided with a wiring aperture penetrating in the thickness direction at a position corresponding to the terminal areas of the actuator unit  73 . In the wiring aperture, there are exposed the electrode terminals in the terminal areas described above. These electrode terminals are connected to wiring members not shown connected to the printer main body. 
     In the recording head  70  having such a configuration, the ink is introduced from an ink cartridge to fill the reservoir, the ink supply channels  712 , the pressure chambers  711 , and the flow channels to the nozzles  721  with the ink. Then, when the piezoelectric elements  5  corresponding respectively to the pressure chambers  711  are driven due to the supply of the drive signal from the printer main body, the areas (the flexible parts) corresponding to the pressure chambers  711  of the vibrating plate  731  are displaced to cause pressure variations in the respective pressure chambers  711 . By controlling the pressure variations, the ink is ejected from the respective nozzles  721 . 
     In a printer  100  such as described above, since the piezoelectric elements  5  described in the above embodiments are provided to the recording head  70 , the equipment reliability of the recording head  70  can be enhanced, and at the same time, the equipment reliability of the printer  100  can also be enhanced. 
     MODIFIED EXAMPLES 
     It should be noted that the invention is not limited to each of the embodiments described above, but includes modifications and improvements within a range where the advantages of the invention can be achieved, and configurations, which can be obtained by, for example, arbitrarily combining the embodiments. 
     In the second embodiment described above, there is shown the example in which the lower electrode main body  511  as the first electrode layer and the lower electrode connection part  512  as the first conductive layer are formed at the same time in the step S 1 , but this is not a limitation. For example, the electrode material is deposited on the vibrating film  412 , and then the lower electrode main body  511  as the first electrode layer is formed by etching. Subsequently, the electrode material is deposited once again, and then the lower electrode connection part  512  as the first conductive layer is patterned by etching. In such a configuration, it is also possible to form the lower electrode main body  511  and the lower electrode connection part  512  to have respective thickness dimensions different from each other. For example, it is possible to make the thickness dimension of the lower electrode main body  511  driven as the active section  50  smaller compared to that of the lower electrode connection part  512 , and it is possible to make the thickness dimension of the lower electrode connection part  512  larger in order to reduce the electrical resistance. 
     In the second embodiment, the upper electrode  52  is formed in the step S 4  and the step S 11 , and then the connection electrode  53  is formed in the step S 12  and the step S 13 . In contrast, it is also possible to perform, for example, the step S 12  and the step S 13  in advance to form the connection electrode  53 , and then perform the step S 4  and the step S 11  to form the upper electrode  52 . 
     In each of the embodiments described above, there is shown the example in which the void (the void  512 A) between the lower electrode main body  511  and the lower electrode connection part  512  is filled with the connection electrode part  523  (or the connection electrode  53 ) to thereby electrically connect the lower electrode main body  511  and the lower electrode connection part  512  to each other, but this example is not a limitation. 
     For example, it is also possible to adopt a configuration in which the connection electrode part  523  (or the connection electrode  53 ) is provided with a first extending part extending toward the +X side so as to overlap a part of the lower electrode main body  511  in the X-Y plane, a second extending part extending toward the +X side so as to overlap a part of the lower electrode connection part  512 , and a connection part for connecting the first extending part and the second extending part to each other. 
     Further, there is shown the example in which the connection electrode part  523  (or the connection electrode  53 ) is continuously disposed from the piezoelectric outer periphery  62  in the upper surface (the surface on the opposite side to the element substrate  41 ) of the piezoelectric film  6  to the lower electrode connection part  512 , but this is not a limitation. For example, it is also possible for the connection electrode part  523  (or the connection electrode  53 ) to be continuously disposed from a tilted surface tilted from the upper surface to the lower surface (the surface on the element substrate  41  side) in the outer edge part of the piezoelectric film  6  to the lower electrode connection part  512 . Further, it is also possible to adopt a configuration in which the connection electrode part  523  (or the connection electrode  53 ) does not overlap the piezoelectric film  6  but is disposed on the void  512 A in a pinpoint manner to have contact with the lower electrode main body  511  and the lower electrode connection part  512 . 
     Although in each of the embodiments, the lower electrode  51 , the upper electrode  52 , and the connection electrode  53  are formed of a metal material, this is not a limitation. For example, it is also possible for the upper electrode  52  and the connection electrode  53  to be formed using a tin oxide type conductive material such as indium tin oxide (ITO) or fluorine-doped tin oxide (FTO), a zinc oxide type conductive material, an oxide conductive material such as strontium ruthenate (SrRuO 3 ), lanthanum nickelate (LaNiO 3 ), or element-doped strontium titanate, or a conductive polymer. 
     Although in each of the embodiments, the active section  50  of the piezoelectric element  5  is formed inside the outer peripheral edge of the aperture  411 A (the flexible membrane  412 A) in the plan view, this is not a limitation. For example, it is also possible for the outer peripheral edge of the active section  50  to be located outside the outer peripheral edge of the aperture  411 A (the flexible membrane  412 A). 
     In each of the embodiments described above, there is illustrated the configuration in which the piezoelectric element  5  and the sealing plate  42  are disposed on the opposite side to the substrate main body  411  (the aperture  411 A) of the vibrating film  412 , the acoustic layer  43  and the acoustic lens  44  are provided to the substrate main body  411 , and the transmission and the reception of the ultrasonic wave are performed through the surface on the substrate main body  411  side, but this is not a limitation. For example, the piezoelectric element  5 , the acoustic layer  43  and the acoustic lens  44  are provided on the opposite side to the substrate main body  411  of the vibrating film  412 , the sealing plate  42  (a reinforcing plate) is provided on the substrate main body  411  side, and the transmission and the reception of the ultrasonic wave are performed through the surface on the opposite side to the substrate main body  411 . 
     In each of the embodiments described above, the ultrasonic measurement apparatus  1  taking an organ in a living body as the measurement object, and the printer  100  are illustrated as the electronic apparatuses, but this is not a limitation. For example, the configurations of the embodiments and the modified examples described above can be applied to a measurement apparatus taking a variety of types of structures as the measurement object, and performing the detection of the defects and inspection of aging of the structures. Further, the same applies to a measurement apparatus taking, for example, a semiconductor package or a wafer as the measurement object, and detecting the defects of the measurement object. 
     Besides the above, specific structures to be adopted when implementing the invention can be configured by arbitrarily combining the embodiments and the modified examples described above with each other, or can arbitrarily be replaced with other structures within the range in which the advantages of the invention can be achieved.