JP2019025796A - Liquid injection head and liquid injection device - Google Patents

Abstract

To suppress occurrence of cracks in a piezoelectric layer.SOLUTION: A liquid injection head comprises: a pressure chamber storing liquid; a diaphragm constituting a wall surface of the pressure chamber; and a piezoelectric device vibrating the diaphragm. The piezoelectric device comprises: a first electrode; a piezoelectric layer; a second electrode; first wiring electrically connected to the second electrode; and an insulation layer, and includes: a first lamination region where the first electrode, the piezoelectric layer and the second electrode are laminated in this order; and a second lamination region positioned at a first end side of the piezoelectric layer, where the first electrode, the piezoelectric layer, the insulation layer and the first wiring are laminated in this order. A first pressure chamber end portion where a wall surface at the first end side of the piezoelectric layer in the pressure chamber and the diaphragm intersect with each other overlaps with the second lamination region in a plan view.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a structure of a liquid jet head, for example.

  2. Description of the Related Art Conventionally, a liquid ejecting head that ejects liquid in a pressure chamber from a nozzle by vibrating a diaphragm constituting a wall surface of the pressure chamber with a piezoelectric element has been proposed. For example, Patent Literature 1 discloses a piezoelectric element having a laminated structure in which a piezoelectric layer is interposed between a first electrode and a second electrode. A drive signal is supplied to the second electrode formed on the surface of the piezoelectric element via a signal wiring. The signal wiring is formed on one end side of the long piezoelectric element.

JP 2014-151623 A

  However, in the configuration of Patent Document 1, the wall surface of the pressure chamber is located at a position that does not overlap with the signal wiring in a plan view in the region where the piezoelectric layer is formed, and the area restricted by the partition wall of the pressure chamber in the piezoelectric layer. Is big. Therefore, it is difficult to ensure a sufficient amount of displacement of the piezoelectric element. On the other hand, from the viewpoint of securing the displacement amount of the piezoelectric element, a configuration in which the wall surface of the pressure chamber is positioned outside the region where the piezoelectric layer is formed is also assumed. However, it is difficult to ensure sufficient mechanical strength in the region where the piezoelectric layer is not formed. Therefore, for example, cracks may occur in the diaphragm. In view of the above circumstances, a preferred aspect of the present invention aims to suppress the occurrence of cracks in the piezoelectric layer and the diaphragm while ensuring the amount of displacement of the piezoelectric layer.

<Aspect 1>
In order to solve the above-described problems, a liquid jet head according to a preferred aspect (aspect 1) of the present invention includes a pressure chamber that stores liquid, a diaphragm that forms a wall surface of the pressure chamber, and the diaphragm. A liquid ejecting head including a piezoelectric device that vibrates, wherein the piezoelectric device includes a first electrode, a piezoelectric layer, a second electrode, and a first wiring electrically connected to the second electrode; An insulating layer, the first electrode, the piezoelectric layer, and the second electrode are stacked in this order, and the first layer is located on a first end side of the piezoelectric layer, A second laminated region in which one electrode, the piezoelectric layer, the insulating layer, and the first wiring are laminated in this order, and the wall surface on the first end side of the piezoelectric layer in the pressure chamber, The first pressure chamber end where the diaphragm intersects overlaps the second stacked region in plan view. In the above aspect, the first pressure chamber end portion of the pressure chamber overlaps with the second stacked region in which the first electrode, the piezoelectric layer, the insulating layer, and the first wiring are stacked in plan view. That is, for example, the mechanical strength of the diaphragm in the vicinity of the first pressure chamber end is reinforced compared to a configuration in which the first pressure chamber end is positioned outside the range where the piezoelectric layer is formed. Therefore, it is possible to suppress the occurrence of cracks in the vicinity of the end portion of the first pressure chamber in the diaphragm.
<Aspect 2>
In a preferred example (aspect 2) of aspect 1, the second electrode is formed on the surface of the piezoelectric layer, the first wiring is formed on the surface of the insulating layer, and the surface of the piezoelectric layer. The first pressure chamber end is electrically connected to the second electrode, and the end of the first pressure chamber is connected to the first electrode, the piezoelectric layer, the second electrode, the insulating layer, and the first wiring in the second stacked region. And overlaps with a region laminated in this order (for example, the laminated region Da in FIGS. 11 and 12) in plan view. In the above aspect, the end of the first pressure chamber overlaps the region where the first electrode, the piezoelectric layer, the second electrode, the insulating layer, and the first wiring are stacked in the second stacked region. Therefore, the effect that generation | occurrence | production of the crack in the vicinity of the 1st pressure chamber edge part can be suppressed among diaphragms is remarkable.
<Aspect 3>
In a preferred example (Aspect 3) of Aspect 1 or Aspect 2, the piezoelectric device includes a second wiring electrically connected to the electrode portion, and the second opposite to the first end in the piezoelectric layer. It is located on the second end side, and includes a third laminated region in which the first electrode, the piezoelectric layer, the insulating layer, and the second wiring are laminated in this order. In the above aspect, since the first wiring is formed on the first end side of the piezoelectric element and the second wiring is formed on the second end side opposite to the first end, the second wiring is not formed. Thus, the rigidity of the portion on the second end side of the piezoelectric element increases. Further, in the piezoelectric layer, the difference in mechanical rigidity between the first end side and the second end side is reduced. Therefore, it is possible to suppress the occurrence of cracks in the piezoelectric layer. Further, since a voltage lower than the voltage applied to the piezoelectric layer in the first stacked region is applied to the piezoelectric layer in the third stacked region, the piezoelectric body is between the first stacked region and the third stacked region. The difference in stress acting on the layer is reduced. Even from the above viewpoint, it is possible to suppress the occurrence of cracks in the piezoelectric layer.
<Aspect 4>
In a preferred example of the aspect 3 (aspect 4), the second pressure chamber end where the wall surface on the second end side of the piezoelectric layer in the pressure chamber intersects the diaphragm is the third laminated layer in plan view Overlapping area. In the above aspect, the second pressure chamber end of the pressure chamber overlaps with the third stacked region in which the first electrode, the piezoelectric layer, the insulating layer, and the second wiring are stacked in plan view. That is, for example, the mechanical strength of the diaphragm in the vicinity of the second pressure chamber end is reinforced compared to a configuration in which the second pressure chamber end is positioned outside the range where the piezoelectric layer is formed. Therefore, it is possible to suppress the generation of cracks in the vicinity of the second pressure chamber end portion of the diaphragm.
<Aspect 5>
In a preferred example (Aspect 5) of Aspect 3 or Aspect 4, the second pressure chamber end portion includes, in the third stacked region, the first electrode, the piezoelectric layer, the second electrode, and the insulating layer. The second wiring overlaps with a region in which the second wiring is stacked in this order (for example, the stacked region Db in FIGS. 11 and 12) in plan view. In the above aspect, the end of the second pressure chamber overlaps the region where the first electrode, the piezoelectric layer, the second electrode, the insulating layer, and the second wiring are stacked in the third stacked region. Therefore, the effect of suppressing the occurrence of cracks in the vicinity of the second pressure chamber end portion of the diaphragm is remarkable.
<Aspect 6>
A liquid ejecting apparatus according to a preferred aspect (aspect 6) of the present invention includes the liquid ejecting head according to any of the aspects exemplified above. A good example of the liquid ejecting apparatus is a printing apparatus that ejects ink, but the use of the liquid ejecting apparatus according to the present invention is not limited to printing.

1 is a configuration diagram of a liquid ejecting apparatus according to a first embodiment. FIG. 3 is an exploded perspective view of a liquid ejecting head. FIG. 3 is a cross-sectional view of the liquid jet head (a cross-sectional view taken along line III-III in FIG. 2). It is a top view of a plurality of piezoelectric devices. It is sectional drawing of the VV line in FIG. It is a circuit diagram which shows the electrical structure in a 1st area | region. It is a circuit diagram which shows the electrical structure in a 2nd area | region. It is a circuit diagram which shows the electrical structure in a 3rd area | region. 3 is a cross-sectional view of a piezoelectric device according to Comparative Example 1. FIG. 3 is a cross-sectional view of a piezoelectric device according to Comparative Example 2. FIG. It is a top view of a plurality of piezoelectric devices in a 2nd embodiment. It is sectional drawing of the XII-XII line | wire in FIG. It is a top view of a plurality of piezoelectric devices in a 3rd embodiment. It is sectional drawing of the XIV-XIV line | wire in FIG. It is sectional drawing of the piezoelectric device in a modification. It is sectional drawing of the piezoelectric device in a modification.

<First Embodiment>
FIG. 1 is a configuration diagram illustrating a liquid ejecting apparatus 100 according to the first embodiment of the invention. The liquid ejecting apparatus 100 according to the first embodiment is an ink jet printing apparatus that ejects ink, which is an example of a liquid, onto a medium (ejection target) 12. The medium 12 is typically printing paper, but a printing target of an arbitrary material such as a resin film or a fabric is used as the medium 12. As illustrated in FIG. 1, the liquid ejecting apparatus 100 is provided with a liquid container 14 that stores ink. For example, a cartridge that can be attached to and detached from the liquid ejecting apparatus 100, a bag-shaped ink pack formed of a flexible film, or an ink tank that can be refilled with ink is used as the liquid container 14.

  As illustrated in FIG. 1, the liquid ejecting apparatus 100 includes a control unit 20, a transport mechanism 22, a moving mechanism 24, and a liquid ejecting head 26. The control unit 20 includes, for example, a processing circuit such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array) and a storage circuit such as a semiconductor memory, and comprehensively controls each element of the liquid ejecting apparatus 100. The transport mechanism 22 transports the medium 12 in the Y direction (Y1, Y2) under the control of the control unit 20.

  The moving mechanism 24 reciprocates the liquid jet head 26 in the X direction (X1, X2) under the control of the control unit 20. The X direction is a direction that intersects (typically orthogonal) the Y direction in which the medium 12 is conveyed. The moving mechanism 24 of the first embodiment includes a substantially box-shaped transport body 242 (carriage) that houses the liquid ejecting head 26 and a transport belt 244 to which the transport body 242 is fixed. A configuration in which a plurality of liquid ejecting heads 26 are mounted on the transport body 242 or a configuration in which the liquid container 14 is mounted on the transport body 242 together with the liquid ejecting head 26 may be employed.

  The liquid ejecting head 26 ejects ink supplied from the liquid container 14 to the medium 12 from a plurality of nozzles (ejection holes) under the control of the control unit 20. In parallel with the transport of the medium 12 by the transport mechanism 22 and the reciprocating reciprocation of the transport body 242, each liquid ejecting head 26 ejects ink onto the medium 12, thereby forming a desired image on the surface of the medium 12. .

  2 is an exploded perspective view of the liquid jet head 26, and FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 (a cross section parallel to the XZ plane). As illustrated in FIG. 2, a direction perpendicular to the XY plane (for example, a plane parallel to the surface of the medium 12) is hereinafter referred to as a Z direction (Z1, Z2). The ink ejection direction (typically the vertical direction) by each liquid ejection head 26 corresponds to the Z direction. As illustrated in FIG. 2, in the following description, one side in the X direction is denoted as “X1 side” and the other side is denoted as “X2 side”. Similarly, one side in the Y direction is denoted as “Y1 side”, the other side is denoted as “Y2 side”, one side in the Z direction is denoted as “Z1 side”, and the other side is denoted as “Z2 side”. write.

  As illustrated in FIGS. 2 and 3, the liquid ejecting head 26 includes a substantially rectangular channel substrate 32 that is long in the Y direction. On the surface of the flow path substrate 32 on the Z2 side in the Z direction, a pressure chamber substrate 34, a diaphragm 36, a plurality of piezoelectric devices 38, a casing 42, and a sealing body 44 are installed. On the other hand, a nozzle plate 46 and a vibration absorber 48 are installed on the surface of the flow path substrate 32 on the Z1 side in the Z direction. Each element of the liquid jet head 26 is generally a plate-like member that is long in the Y direction, similarly to the flow path substrate 32, and is bonded to each other using, for example, an adhesive.

  As illustrated in FIG. 2, the nozzle plate 46 is a plate-like member on which a plurality of nozzles N arranged in the Y direction are formed. Each nozzle N is a through hole through which ink passes. The flow path substrate 32, the pressure chamber substrate 34, and the nozzle plate 46 are formed, for example, by processing a silicon (Si) single crystal substrate by a semiconductor manufacturing technique such as etching. However, the material and manufacturing method of each element of the liquid jet head 26 are arbitrary. The Y direction can be rephrased as the direction in which the plurality of nozzles N are arranged.

  The flow path substrate 32 is a plate-like member for forming an ink flow path. As illustrated in FIGS. 2 and 3, the channel substrate 32 is formed with an opening 322, a supply channel 324, and a communication channel 326. The opening 322 is a through hole formed in a long shape along the Y direction in a plan view (that is, viewed from the Z direction) so as to be continuous over the plurality of nozzles N. On the other hand, the supply flow path 324 and the communication flow path 326 are through holes formed individually for each nozzle N. In addition, as illustrated in FIG. 3, a relay flow path 328 extending over a plurality of supply flow paths 324 is formed on the surface of the flow path substrate 32 on the Z1 side in the Z direction. The relay channel 328 is a channel that connects the opening 322 and the plurality of supply channels 324.

  The casing 42 is a structure manufactured by, for example, injection molding of a resin material, and is fixed to the surface on the Z2 side in the Z direction of the flow path substrate 32. As illustrated in FIG. 3, the housing portion 42 is formed with a housing portion 422 and an introduction port 424. The accommodating portion 422 is a concave portion having an outer shape corresponding to the opening portion 322 of the flow path substrate 32, and the introduction port 424 is a through hole communicating with the accommodating portion 422. As understood from FIG. 3, a space in which the opening 322 of the flow path substrate 32 and the accommodating portion 422 of the housing portion 42 communicate with each other functions as a liquid storage chamber (reservoir) R. The ink supplied from the liquid container 14 and passing through the inlet 424 is stored in the liquid storage chamber R.

  The vibration absorber 48 is an element for absorbing pressure fluctuation in the liquid storage chamber R, and includes, for example, a flexible sheet member (compliance substrate) that can be elastically deformed. Specifically, the Z direction of the flow path substrate 32 is configured such that the opening 322, the relay flow path 328, and the plurality of supply flow paths 324 of the flow path substrate 32 are closed to form the bottom surface of the liquid storage chamber R. A vibration absorber 48 is installed on the surface on the Z1 side.

  As illustrated in FIGS. 2 and 3, the pressure chamber substrate 34 is a plate-like member in which a plurality of pressure chambers C corresponding to different nozzles N are formed. The plurality of pressure chambers C are arranged along the Y direction. Each pressure chamber C (cavity) is a long opening along the X direction in plan view. The end of the pressure chamber C on the X1 side in the X direction overlaps with one supply channel 324 of the flow path substrate 32 in plan view, and the end of the pressure chamber C on the X2 side in the X direction in plan view. It overlaps with one communication channel 326 of 32.

A diaphragm 36 is installed on the surface of the pressure chamber substrate 34 opposite to the flow path substrate 32. The diaphragm 36 is a plate-like member that can be elastically deformed. As illustrated in FIG. 3, the diaphragm 36 according to the first embodiment is configured by stacking a first layer 361 and a second layer 362. The second layer 362 is located on the side opposite to the pressure chamber substrate 34 when viewed from the first layer 361. The first layer 361 is an elastic film formed of an elastic material such as silicon oxide (SiO ₂ ), and the second layer 362 is an insulating film formed of an insulating material such as zirconium oxide (ZrO ₂ ). In addition, by selectively removing a part of the plate-like member having a predetermined plate thickness in the plate thickness direction from the region corresponding to the pressure chamber C, the pressure chamber substrate 34 and a part or all of the diaphragm 36 are removed. It is also possible to form it integrally.

  As understood from FIG. 3, the flow path substrate 32 and the vibration plate 36 face each other with an interval inside each pressure chamber C. The pressure chamber C is a space that is located between the flow path substrate 32 and the vibration plate 36 and applies pressure to the ink filled in the pressure chamber C. The ink stored in the liquid storage chamber R branches from the relay flow path 328 to each supply flow path 324 and is supplied and filled in the plurality of pressure chambers C in parallel. As understood from the above description, the diaphragm 36 constitutes the wall surface of the pressure chamber C (specifically, the upper surface which is one surface of the pressure chamber C).

  As illustrated in FIGS. 2 and 3, the surface of the diaphragm 36 opposite to the pressure chamber C (that is, the surface of the second layer 362) corresponds to a different nozzle N (or pressure chamber C). A plurality of piezoelectric devices 38 are installed. Each piezoelectric device 38 is an actuator that is deformed by the supply of a drive signal, and is formed in a long shape along the X direction in plan view. The plurality of piezoelectric devices 38 are arranged in the Y direction so as to correspond to the plurality of pressure chambers C. When the vibration plate 36 vibrates in conjunction with the deformation of the piezoelectric device 38, the pressure in the pressure chamber C fluctuates, so that the ink filled in the pressure chamber C is ejected through the communication channel 326 and the nozzle N. Is done.

  2 and 3 is a structure that protects the plurality of piezoelectric devices 38 and reinforces the mechanical strength of the pressure chamber substrate 34 and the diaphragm 36. For example, the sealing body 44 is bonded to the surface of the diaphragm 36. It is fixed with an agent. A plurality of piezoelectric devices 38 are accommodated inside a recess formed in a surface of the sealing body 44 facing the diaphragm 36.

  As illustrated in FIG. 3, for example, a wiring substrate 50 is bonded to the surface of the vibration plate 36 (or the surface of the pressure chamber substrate 34). The wiring board 50 is a mounting component on which a plurality of wirings (not shown) for electrically connecting the control unit 20 or the power supply circuit (not shown) and the liquid jet head 26 are formed. For example, a flexible wiring board 50 such as FPC (Flexible Printed Circuit) or FFC (Flexible Flat Cable) is preferably employed. A drive signal for driving the piezoelectric device 38 is supplied from the wiring board 50 to each piezoelectric device 38.

  A specific configuration of each piezoelectric device 38 will be described in detail below. FIG. 4 is a plan view of the plurality of piezoelectric devices 38. In FIG. 4, the peripheral edge of the element located on the back side of any one element (originally a part hidden by the near element) is also shown for convenience. 5 is a cross-sectional view taken along the line VV in FIG. 4 (a cross section along the longitudinal direction of the piezoelectric device 38).

  As illustrated in FIGS. 4 and 5, the piezoelectric device 38 is configured by stacking a first electrode 51, a piezoelectric layer 52, a second electrode 53, an insulating layer 54, a first wiring 55, and a second wiring 56. The In the present specification, the expression “element A and element B are stacked” is not limited to a configuration in which element A and element B are in direct contact with each other. That is, a configuration in which another element C is interposed between the element A and the element B is also included in the concept that “the element A and the element B are stacked”. Similarly, the expression “element B is formed on the surface of element A” is not limited to a configuration in which element A and element B are in direct contact with each other. That is, even in the configuration in which the element C is formed on the surface of the element A and the element B is formed on the surface of the element C, as long as at least a part of the element A and the element B overlaps in plan view, The element B is formed on the surface of “

  The first electrode 51 is formed on the surface of the diaphragm 36 (specifically, the surface of the second layer 362). Specifically, the first electrode 51 is a strip-like common electrode extending in the Y direction so as to be continuous over the plurality of piezoelectric devices 38 (or the plurality of pressure chambers C). A predetermined reference voltage Vbs is applied to the end portion of the first electrode 51 in the Y direction, for example, from the wiring board 50.

  The piezoelectric layer 52 is formed on the surface of the first electrode 51. The piezoelectric layer 52 is individually formed for each piezoelectric device 38 (or for each pressure chamber C) and overlaps the pressure chamber C in plan view. That is, a plurality of piezoelectric layers 52 that are long in the X direction are arranged in the Y direction with a space therebetween. The material or manufacturing method of the piezoelectric layer 52 is arbitrary. For example, a piezoelectric material layer 52 is formed by forming a thin film of a piezoelectric material such as lead zirconate titanate by a known film forming technique such as sputtering and selectively removing the thin film by a known processing technique such as photolithography. Can be formed.

  As illustrated in FIGS. 4 and 5, the end portion Eb1 (example of the first end) on the X1 side in the X direction in the piezoelectric layer 52 is on the X2 side in the X direction when viewed from the end portion Ea1 of the first electrode 51. To position. Further, the end portion Eb2 (example of the second end) on the X2 side in the X direction in the piezoelectric layer 52 is located on the X1 side in the X direction when viewed from the end portion Ea2 of the first electrode 51. As understood from the above description, each piezoelectric layer 52 is located inside the range where the first electrode 51 is formed. That is, as illustrated in FIGS. 4 and 5, the first electrode 51 includes a first portion S1 in which the piezoelectric layer 52 is stacked, and a second portion S2 and a third portion S3 in which the piezoelectric layer 52 is not stacked. including. The first portion S1 is a region overlapping the piezoelectric layer 52 in a plan view, and the second portion S2 and the third portion S3 are regions protruding from the periphery of the piezoelectric layer 52 in the X direction in a plan view. The second portion S2 is a region on the X1 side (end Ea1 side) in the X direction when viewed from the first portion S1. The third portion S3 is a region opposite to the second portion S2 with respect to the first portion S1 (X2 side in the X direction when viewed from the first portion S1).

  The second electrode 53 is formed on the surface of the piezoelectric layer 52. The second electrode 53 is an individual electrode formed individually for each piezoelectric device 38 (or for each pressure chamber C). Specifically, a plurality of second electrodes 53 extending in the X direction are arranged in the Y direction at intervals. The material or manufacturing method of the second electrode 53 is arbitrary. For example, a second electrode 53 is formed by forming a thin film of a conductive material such as platinum or iridium by a known film formation technique such as sputtering and selectively removing the thin film by a known processing technique such as photolithography. Is possible.

  The end portion Ec1 on the X1 side in the X direction of the second electrode 53 is located on the X2 side in the X direction when viewed from the end portion Eb1 of the piezoelectric layer 52. Further, the end portion Ec2 on the X2 side in the X direction of the second electrode 53 is located on the X1 side in the X direction when viewed from the end portion Eb2 of the piezoelectric layer 52. Further, the second electrode 53 is located inside the piezoelectric layer 52 also in the Y direction. As understood from the above description, the second electrode 53 is located inside the range in which the piezoelectric layer 52 is formed.

  As illustrated in FIG. 5, the piezoelectric element P is configured by stacking the first electrode 51, the piezoelectric layer 52, and the second electrode 53. Piezoelectric elements P are individually formed for each pressure chamber C (or for each nozzle N). Specifically, a plurality of piezoelectric elements P that are long in the X direction are arranged in the Y direction at intervals. A portion of the piezoelectric layer 52 sandwiched between the first electrode 51 and the second electrode 53 (so-called active portion) is a reference voltage Vbs applied to the first electrode 51 and a drive signal supplied to the second electrode 53. It deforms according to the voltage difference from Vdr. Note that the Z direction can also be referred to as a direction in which a plurality of layers constituting the piezoelectric element P are stacked.

The insulating layer 54 is an insulating film that covers the surface of the diaphragm 36 on which the plurality of piezoelectric elements P are formed. That is, the insulating layer 54 covers the first electrode 51, the piezoelectric layer 52, and the second electrode 53. The insulating layer 54 is formed of an insulating material such as silicon oxide (SiO _x ) or silicon nitride (SiN _x ).

  The first wiring 55 is a conductive layer formed on the surface of the insulating layer 54. The first wiring 55 is individually formed for each piezoelectric element P (or for each pressure chamber C). Specifically, a plurality of first wires 55 that are long in the X direction are arranged in the Y direction at intervals.

  As illustrated in FIGS. 4 and 5, the first wiring 55 is formed on the end portion Eb <b> 1 side of the piezoelectric layer 52. That is, the first wiring 55 overlaps the end portion Eb1 of the piezoelectric layer 52 in plan view. Specifically, the end portion Ed1 on the X1 side in the X direction of the first wiring 55 is located on the X1 side in the X direction when viewed from the end portion Ea1 of the first electrode 51. The end portion Ed2 on the X2 side in the X direction of the first wiring 55 is located on the X2 side in the X direction when viewed from the end portion Ec1 of the second electrode 53. As understood from the above description, the first wiring 55 is on the surface of the piezoelectric layer 52 and the second electrode 53 and on the surface of the second portion S2 of the first electrode 51 (the portion not overlapping the piezoelectric layer 52). And continuous. 4 exemplifies a configuration in which the first wiring 55 is wider than the piezoelectric layer 52, the wiring width of the first wiring 55 is arbitrary.

  A portion of the first wiring 55 on the end Ed2 side located on the surface of the piezoelectric layer 52 is connected to the second electrode 53 via a contact hole H1 (example of the first contact hole) formed in the insulating layer 54. Electrically connected. Further, the portion of the first wiring 55 on the X1 side in the X direction as viewed from the end portion Eb1 of the piezoelectric layer 52 overlaps the second portion S2 of the first electrode 51 with the insulating layer 54 interposed therebetween in a plan view. Therefore, the first wiring 55 (and the second electrode 53) and the first electrode 51 are electrically insulated. A portion of the first wiring 55 on the end Ed1 side is electrically connected to the wiring of the wiring board 50. In the above configuration, the drive signal Vdr supplied from the wiring board 50 (exemplary external circuit) to the first wiring 55 is supplied to the second electrode 53 via the first wiring 55.

  The second wiring 56 is a conductive layer formed on the surface of the insulating layer 54. The second wiring 56 is individually formed for each piezoelectric element P (or for each pressure chamber C). Specifically, a plurality of second wirings 56 that are long in the X direction are arranged in the Y direction at intervals.

  As illustrated in FIGS. 4 and 5, the second wiring 56 is formed on the end portion Eb <b> 2 side of the piezoelectric layer 52. That is, the second wiring 56 overlaps the end portion Eb2 of the piezoelectric layer 52 in plan view. Specifically, the end Ee1 on the X1 side in the X direction of the second wiring 56 is located on the X1 side in the X direction when viewed from the end Ec2 of the second electrode 53. In addition, the end Ee2 on the X2 side in the X direction of the second wiring 56 is located on the X2 side in the X direction when viewed from the end Ea2 of the first electrode 51. As understood from the above description, the second wiring 56 is on the surface of the piezoelectric layer 52 and the second electrode 53 and on the surface of the third portion S3 of the first electrode 51 (the portion not overlapping the piezoelectric layer 52). And continuous. That is, the first wiring 55 and the second wiring 56 are generally formed symmetrically with respect to the YZ plane. 4 illustrates the configuration in which the second wiring 56 is wider than the piezoelectric layer 52, the wiring width of the second wiring 56 is arbitrary.

  A portion of the second wiring 56 on the X2 side in the X direction when viewed from the end Eb2 of the piezoelectric layer 52 overlaps the third portion S3 of the first electrode 51 with the insulating layer 54 interposed therebetween in a plan view. That is, the second wiring 56 and the first electrode 51 are electrically insulated. On the other hand, the portion on the end Ee1 side of the second wiring 56 overlaps the portion on the end Ec2 side of the second electrode 53 on the surface of the piezoelectric layer 52 in plan view. A portion of the second wiring 56 on the end Ee1 side located on the surface of the piezoelectric layer 52 is connected to the second electrode 53 via a contact hole H2 (illustrated as a second contact hole) formed in the insulating layer 54. Electrically connected. That is, the second wiring 56 is electrically connected to the wiring of the wiring board 50 through the second electrode 53 and the first wiring 55. Accordingly, the drive signal Vdr supplied from the wiring board 50 to the first wiring 55 is also supplied to the second wiring 56 via the second electrode 53.

  The first wiring 55 and the second wiring 56 are collectively formed by selectively removing a common conductive layer (single layer or a plurality of layers). Therefore, the first wiring 55 and the second wiring 56 are formed to have substantially the same film thickness using a common conductive material. For example, the first wiring 55 is formed by forming a conductive layer of a low-resistance metal such as gold by a known film formation technique such as sputtering and selectively removing the conductive layer by a known processing technique such as photolithography. And the second wiring 56 are collectively formed. The first wiring 55 and the second wiring 56 are thicker than the second electrode 53. For example, the second electrode 53 is formed with a sufficiently thin film thickness so as not to excessively suppress deformation of the piezoelectric layer 52. On the other hand, with respect to the first wiring 55 and the second wiring 56, the corresponding film thickness is ensured so that the wiring resistance is sufficiently reduced.

  As illustrated in FIGS. 4 and 5, the range in which the piezoelectric layer 52 is formed in the piezoelectric device 38 is divided into a first region Q1, a second region Q2, and a third region Q3 in plan view. The second region Q2 is a region on the end Eb1 side in the piezoelectric layer 52, and the third region Q3 is a region on the end Eb2 side in the piezoelectric layer 52. The first region Q1 is a region between the second region Q2 and the third region Q3. That is, the second region Q2 is located on the X1 side in the X direction as viewed from the first region Q1, and the third region Q3 on the X2 side in the X direction is located as viewed from the first region Q1.

  The first region Q1 is a region where the first wiring 55 and the second wiring 56 are not formed. Therefore, in the first region Q1 (active portion), the first electrode 51 (first portion S1), the piezoelectric layer 52, and the second electrode 53 are laminated in this order from the diaphragm 36 side. On the other hand, the second region Q2 is a region where the first wiring 55 is formed. Therefore, in the second region Q2, the first electrode 51 (second portion S2), the piezoelectric layer 52, the insulating layer 54, and the first wiring 55 are laminated in this order from the diaphragm 36 side. The third region Q3 is a region where the second wiring 56 is formed. Accordingly, in the third region Q3, the first electrode 51 (third portion S3), the piezoelectric layer 52, the insulating layer 54, and the second wiring 56 are laminated in this order from the diaphragm 36 side.

  As illustrated in FIG. 6, a capacitive element Cp having the piezoelectric layer 52 as a dielectric is formed between the first electrode 51 and the second electrode 53 in the first region Q1. On the other hand, in the second region Q2, the piezoelectric layer 52 and the insulating layer 54 are interposed between the first electrode 51 and the first wiring 55. That is, in the second region Q2, as illustrated in FIG. 7, the capacitive element Cp using the piezoelectric layer 52 as a dielectric and the capacitive element Cs using the insulating layer 54 as a dielectric are connected to the first electrode 51. The first wiring 55 is connected in series. In the third region Q 3, the piezoelectric layer 52 and the insulating layer 54 are interposed between the first electrode 51 and the second wiring 56. That is, in the third region Q3, as illustrated in FIG. 8, the capacitive element Cp using the piezoelectric layer 52 as a dielectric and the capacitive element Cs using the insulating layer 54 as a dielectric are connected to the first electrode 51. The second wiring 56 is connected in series.

  As described above, in the first embodiment, the second wiring 56 is formed on the opposite side of the first wiring 55 in the longitudinal direction (X direction) of the piezoelectric layer 52. According to the above configuration, the mechanical rigidity of the portion on the end portion Eb2 side of the piezoelectric layer 52 is ensured to be equal to the end portion Eb1 side on which the first wiring 55 is formed. Therefore, it is possible to suppress the occurrence of cracks in the piezoelectric layer 52 and the diaphragm 36 in the vicinity of the end Eb2.

  FIG. 9 is a cross-sectional view of a configuration in which the second wiring 56 is not formed (hereinafter referred to as “Comparison 1”). As illustrated in FIG. 9, the voltage Va corresponding to the difference between the reference voltage Vbs and the drive signal Vdr is a piezoelectric layer in the region Qa where the first electrode 51 and the second electrode 53 face each other in the comparison 1. 52 is applied. On the other hand, no voltage is applied to the piezoelectric layer 52 in the region Qb located on the X2 side in the X direction when viewed from the region Qa. That is, the piezoelectric layer 52 is deformed in the region Qa according to the voltage Va, but is not deformed in the region Qb. Therefore, a local stress difference is generated at the boundary between the region Qa and the region Qb, and a crack may occur in the piezoelectric layer 52.

  On the other hand, in the third region Q3 of the first embodiment, the piezoelectric layer 52 and the insulating layer 54 are interposed between the first electrode 51 and the second wiring 56. In the above configuration, the voltage Va between the first electrode 51 and the second wiring 56 is divided between the capacitive element Cs and the capacitive element Cp in FIG. Therefore, the voltage Vb applied to the piezoelectric layer 52 is lower than the voltage Va between the first electrode 51 and the second wiring 56. That is, a voltage lower than that of the piezoelectric layer 52 in the first region Q1 is applied to the piezoelectric layer 52 in the third region Q3. Therefore, the stress difference generated at the boundary between the first region Q1 and the third region Q3 in the piezoelectric layer 52 is reduced as compared with the proportional 1. That is, according to the first embodiment, there is an advantage that generation of cracks in the piezoelectric layer 52 can be suppressed not only from the viewpoint of mechanical rigidity but also from the electrical viewpoint described above.

  A planar positional relationship between the pressure chamber C and the piezoelectric device 38 will be described. In the following description, as illustrated in FIG. 4 and FIG. 5, the end portion of the pressure chamber C where the wall surface on the X1 side in the X direction and the surface of the diaphragm 36 (the surface of the first layer 361) intersect. Indicated as c1 (exemplification of the end of the first pressure chamber). In the following description, the portion of the pressure chamber C where the wall surface on the X2 side in the X direction and the surface of the diaphragm 36 intersect will be referred to as an end c2 (exemplification of the second pressure chamber end).

  4 and 5 illustrate the first stacked region L1, the second stacked region L2, and the third stacked region L3. The first stacked region L1 is a region where the first electrode 51, the piezoelectric layer 52, and the second electrode 53 are stacked in this order.

  The second stacked region L2 is a region located on the end Eb1 side of the piezoelectric layer 52 as viewed from the first stacked region L1. In the second stacked region L2, the first electrode 51, the piezoelectric layer 52, the insulating layer 54, and the first wiring 55 are stacked in this order. Specifically, the range between the end portion Eb1 of the piezoelectric layer 52 and the end portion Ed2 of the first wiring 55 corresponds to the second stacked region L2. The aforementioned second region Q2 is included in the second stacked region L2.

  The third stacked region L3 is a region located on the end Eb2 side of the piezoelectric layer 52 as viewed from the first stacked region L1. In the third stacked region L3, the first electrode 51, the piezoelectric layer 52, the insulating layer 54, and the second wiring 56 are stacked in this order. Specifically, the range between the end Eb2 of the piezoelectric layer 52 and the end Ee1 of the second wiring 56 corresponds to the third stacked region L3. The aforementioned third region Q3 is included in the third stacked region L3.

  Of the pressure chamber C, the end c1 on the X1 side in the X direction overlaps the second stacked region L2 in plan view as illustrated in FIGS. 4 and 5. That is, the end c 1 is located between the end Eb 1 of the piezoelectric layer 52 and the end Ed 2 of the first wiring 55. The end c1 of the pressure chamber C in the first embodiment particularly overlaps the second region Q2 in the second stacked region L2 in plan view. That is, the end c 1 is located between the end Eb 1 of the piezoelectric layer 52 and the end Ec 1 of the second electrode 53.

  On the other hand, the end c2 on the X2 side in the X direction in the pressure chamber C overlaps with the third stacked region L3 in plan view as illustrated in FIGS. 4 and 5. That is, the end c2 is located between the end Eb2 of the piezoelectric layer 52 and the end Ee1 of the second wiring 56. The end c2 of the pressure chamber C in the first embodiment particularly overlaps the third region Q3 in the third stacked region L3 in plan view. That is, the end c2 is located between the end Eb2 of the piezoelectric layer 52 and the end Ec2 of the second electrode 53.

  FIG. 10 shows a configuration in which the end c1 of the pressure chamber C is positioned outside the second stacked region L2 and the end c2 of the pressure chamber C is positioned outside the third stacked region L3 (hereinafter referred to as “Comparison 2”). FIG. In contrast 2, the end c1 is located on the X1 side in the X direction when viewed from the end Eb1 of the piezoelectric layer 52, and the end c2 is located on the X2 side in the X direction when viewed from the end Eb2 of the piezoelectric layer 52. To do.

  The displacement of the region of the diaphragm 36 located outside the pressure chamber C is limited by being bonded to the pressure chamber substrate 34. On the other hand, the area inside the pressure chamber C of the diaphragm 36 is more easily displaced than the area outside the pressure chamber C. Therefore, a local stress difference is generated in a portion of the diaphragm 36 that overlaps the end c1 or the end c2 of the pressure chamber C (that is, the boundary between the inside and the outside of the pressure chamber C). There is a tendency that cracks are likely to occur. In contrast 2, the end c1 is located in the region where the two layers of the insulating layer 54 and the first wiring 55 are laminated, and the end c2 is located in the region where the two layers of the insulating layer 54 and the second wiring 56 are laminated. Is located.

  On the other hand, in the second laminated region L2, the mechanical strength of the diaphragm 36 is reinforced by laminating the first electrode 51, the piezoelectric layer 52, the insulating layer 54, and the first wiring 55. In the first embodiment, the end c1 of the pressure chamber C overlaps with the second stacked region L2 in which the mechanical strength is ensured as described above in a plan view. Therefore, according to the first embodiment, it is possible to suppress the occurrence of cracks in the vicinity of the end c <b> 1 of the diaphragm 36 as compared with the comparative 2.

  In the third laminated region L3, the mechanical strength of the diaphragm 36 is reinforced by laminating the first electrode 51, the piezoelectric layer 52, the insulating layer 54, and the second wiring 56. In the first embodiment, the end c2 of the pressure chamber C overlaps with the third stacked region L3 where the mechanical strength is ensured as described above in a plan view. Therefore, according to the first embodiment, it is possible to suppress the occurrence of cracks in the vicinity of the end c <b> 2 of the diaphragm 36 as compared with the comparative 2.

Second Embodiment
A second embodiment of the present invention will be described. In addition, about the element which an effect | action or function is the same as that of 1st Embodiment in each form illustrated below, the code | symbol used by description of 1st Embodiment is diverted, and each detailed description is abbreviate | omitted suitably.

  FIG. 11 is a plan view of a plurality of piezoelectric devices 38 in the second embodiment, and FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. As illustrated in FIGS. 11 and 12, in the second embodiment, the positions of the end c1 and the end c2 of the pressure chamber C are different from those in the first embodiment.

  As illustrated in FIGS. 11 and 12, the second stacked region L2 includes the second region Q2 and the stacked region Da. The stacked region Da is a region where the first electrode 51, the piezoelectric layer 52, the second electrode 53, the insulating layer 54, and the first wiring 55 are stacked (a region other than the second region Q2). That is, the second electrode 53 is not formed in the second region Q2, whereas the second electrode 53 is formed in the stacked region Da.

  In the first embodiment, the configuration in which the end c1 of the pressure chamber C overlaps the second region Q2 of the second stacked region L2 is exemplified. In the second embodiment, as illustrated in FIGS. 11 and 12, the end c1 overlaps the stacked region Da in the second stacked region L2 in plan view. According to the above configuration, the strength of the diaphragm 36 near the end c 1 is reinforced by the amount corresponding to the second electrode 53. Therefore, the effect of suppressing the generation of cracks in the vicinity of the end c1 of the pressure chamber C in the diaphragm 36 is remarkable.

  As illustrated in FIGS. 11 and 12, the third stacked region L3 includes the third region Q3 and the stacked region Db. The stacked region Db is a region where the first electrode 51, the piezoelectric layer 52, the second electrode 53, the insulating layer 54, and the second wiring 56 are stacked (a region other than the third region Q3). That is, the second electrode 53 is not formed in the third region Q3, whereas the second electrode 53 is formed in the stacked region Da.

  In the first embodiment, the configuration in which the end portion c2 of the pressure chamber C overlaps the third region Q3 in the third stacked region L3 is illustrated. In the second embodiment, as illustrated in FIGS. 11 and 12, the end c2 overlaps the stacked region Db in the third stacked region L3 in plan view. According to the above configuration, the strength of the diaphragm 36 near the end c2 is reinforced by the amount of the second electrode 53. Therefore, the effect of suppressing the occurrence of cracks in the vicinity of the end c2 of the pressure chamber C in the diaphragm 36 is remarkable.

<Third Embodiment>

  FIG. 13 is a plan view of a plurality of piezoelectric devices 38 in the third embodiment, and FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. As illustrated in FIGS. 13 and 14, the piezoelectric device 38 of the third embodiment includes a third wiring 57 in addition to the same elements as those of the first embodiment. The third wiring 57 is a strip-like electrode extending in the Y direction so as to be continuous over the plurality of piezoelectric devices 38. The third wiring 57 is formed of a conductive material having a lower resistivity than the first electrode 51. For example, the first wiring 55, the second wiring 56, and the third wiring 57 are collectively formed by selectively removing the common conductive layer.

  As illustrated in FIGS. 13 and 14, the third wiring 57 overlaps a portion of the first electrode 51 on the end Ea2 side in a plan view. Therefore, the third wiring 57 is formed on the side opposite to the first wiring 55 with the second wiring 56 interposed therebetween in plan view. The third wiring 57 is electrically connected to the first electrode 51 through a contact hole H 3 formed in the insulating layer 54. As illustrated in FIG. 4, the contact hole H 3 is formed individually for each piezoelectric device 38, for example. However, the shape and position of the contact hole H3 are arbitrary. For example, a contact hole H3 that is continuous in the X direction across a plurality of piezoelectric devices 38 may be formed. For example, a predetermined reference voltage Vbs is applied to the third wiring 57 from the wiring board 50. The reference voltage Vbs is applied to the first electrode 51 through the third wiring 57.

  In the third embodiment, the same effect as in the first embodiment is realized. In the third embodiment, it is possible to apply a voltage to the first electrode 51 via the third wiring 57. By the way, from the viewpoint of sufficiently securing the deformation amount of the piezoelectric layer 52, it is important to form the first electrode 51 sufficiently thin. However, since the resistance of the first electrode 51 increases as the film thickness of the first electrode 51 is reduced, the voltage drop along the Y direction of the first electrode 51 to the voltage applied from the wiring board 50 to the first electrode 51. Occurs. Due to the voltage drop described above, an error may occur in the voltage applied to the piezoelectric element P of each piezoelectric device 38. In the third embodiment, the third wiring 57 is formed of a conductive material having a lower resistivity than the first electrode 51. Therefore, a voltage drop at the first electrode 51 is suppressed, and as a result, there is an advantage that an error in voltage applied to each piezoelectric element P can be reduced.

  13 and 14, as in the first embodiment, the end c1 of the pressure chamber C is located in the second region Q2, and the end c2 of the pressure chamber C is located in the third region Q3. The structure to perform was illustrated. However, under the configuration in which the third wiring 57 is formed as in the third embodiment, the configuration in which the end c1 of the pressure chamber C is positioned in the stacked region Da as in the second embodiment, or the pressure chamber A configuration in which the end portion c2 of C is positioned in the stacked region Db can also be adopted.

<Modification>
Each form illustrated above can be variously modified. Specific modes of modifications that can be applied to the above-described embodiments are exemplified below. Note that two or more aspects arbitrarily selected from the following examples can be appropriately combined as long as they do not contradict each other.

(1) In each of the above-described embodiments, the configuration in which the insulating layer 54 covers the entire piezoelectric layer 52 is exemplified, but the range in which the insulating layer 54 is formed is not limited to the above examples. For example, as illustrated in FIG. 15, a configuration in which the insulating layer 54 is not formed on part or all of the surface of the second electrode 53 may be employed. In each of the first wiring 55 and the second wiring 56, a portion protruding from the peripheral edge of the insulating layer 54 is electrically connected to the second electrode 53. As understood from the illustration of FIG. 15, the contact hole H1 and the contact hole H2 may be omitted. In the third embodiment, a portion of the third wiring 57 that protrudes from the periphery of the insulating layer 54 may be brought into contact with the first electrode 51. That is, the contact hole H3 is omitted.

(2) In each of the above-described embodiments, the strip-shaped first electrode 51 that is continuous over the plurality of piezoelectric devices 38 is illustrated, but the planar shape of the first electrode 51 is not limited to the above examples. For example, the first electrode 51 may be formed individually for each piezoelectric device 38. In the configuration in which the first electrode 51 is an individual electrode, the piezoelectric layer 52 is formed inside the range where the first electrode 51 is formed.

(3) In the above-described embodiments, the configuration in which the wall surface of the pressure chamber C is perpendicular to the diaphragm 36 is illustrated. However, as illustrated in FIG. 16, the wall surface of the pressure chamber C is the surface of the diaphragm 36 (X− A configuration inclined with respect to the Y plane is also employed. In the configuration of FIG. 16, the end c <b> 1 of the pressure chamber C is a portion where the wall surface (inclined surface) on the X <b> 1 side in the X direction intersects the surface of the diaphragm 36 in the pressure chamber C. Similarly, the end c2 of the pressure chamber C is a portion of the pressure chamber C where the X2 side wall surface (inclined surface) in the X direction intersects the surface of the diaphragm 36. The planar positional relationship between the piezoelectric device 38 and the pressure chamber C is determined so that the end c1 or the end c2 described above satisfies the conditions exemplified in the above-described embodiments.

(4) In each of the above-described embodiments, the second electrode 53 and the first wiring 55 are formed separately. However, the second electrode 53 and the first wiring 55 are integrated from a common conductive layer (single layer or a plurality of layers). You may form in.

(5) The planar shape of the pressure chamber C or the piezoelectric device 38 is not limited to the examples of the above-described embodiments. For example, in a configuration using a silicon (Si) single crystal substrate as the pressure chamber substrate 34, the crystal plane is actually reflected in the planar shape of the pressure chamber C.

(6) In each of the above-described embodiments, the serial type liquid ejecting apparatus 100 that reciprocates the carrier 242 on which the liquid ejecting head 26 is mounted is illustrated. However, the line type liquid in which a plurality of nozzles N are distributed over the entire width of the medium 12. The present invention can also be applied to an injection device.

(7) The liquid ejecting apparatus 100 exemplified in each of the above-described embodiments can be employed in various apparatuses such as a facsimile apparatus and a copying machine in addition to an apparatus dedicated to printing. However, the use of the liquid ejecting apparatus of the present invention is not limited to printing. For example, a liquid ejecting apparatus that ejects a solution of a coloring material is used as a manufacturing apparatus that forms a color filter of a liquid crystal display device. Further, a liquid ejecting apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus that forms wiring and electrodes of a wiring board.

DESCRIPTION OF SYMBOLS 100 ... Liquid ejecting apparatus, 12 ... Medium, 14 ... Liquid container, 20 ... Control unit, 22 ... Conveyance mechanism, 24 ... Moving mechanism, 26 ... Liquid ejecting head, 32 ... Flow path substrate, 34 ... Pressure chamber substrate, 342... Removal portion, 36... Vibration plate, 38... Piezoelectric device, 42 .. casing portion, 44... Sealed body, 46. DESCRIPTION OF SYMBOLS ... Wiring board, 51 ... 1st electrode, 52 ... Piezoelectric layer, 53 ... 2nd electrode, 54 ... Insulating layer, 55 ... 1st wiring, 56 ... 2nd wiring, 57 ... 3rd wiring, C ... Pressure chamber, R: Liquid storage chamber, P: Piezoelectric element.

Claims (6)

A pressure chamber containing liquid;
A diaphragm constituting a wall surface of the pressure chamber;
A liquid ejecting head comprising: a piezoelectric device that vibrates the diaphragm;
The piezoelectric device is
A first electrode;
A piezoelectric layer;
A second electrode;
A first wiring electrically connected to the second electrode;
An insulating layer;
A first laminated region in which the first electrode, the piezoelectric layer, and the second electrode are laminated in this order;
A second laminated region that is located on a first end side of the piezoelectric layer and in which the first electrode, the piezoelectric layer, the insulating layer, and the first wiring are laminated in this order;
The liquid ejecting head, wherein a first pressure chamber end portion where the wall surface on the first end side of the piezoelectric layer in the pressure chamber intersects the diaphragm overlaps the second stacked region in a plan view. The second electrode is formed on the surface of the piezoelectric layer,
The first wiring is formed on the surface of the insulating layer, and is electrically connected to the second electrode on the surface of the piezoelectric layer.
The end of the first pressure chamber is located in a region of the second stacked region where the first electrode, the piezoelectric layer, the second electrode, the insulating layer, and the first wiring are stacked in this order. The liquid jet head according to claim 1, which overlaps in a plan view. The piezoelectric device is
Comprising a second wiring electrically connected to the electrode portion;
A third stack in which the first electrode, the piezoelectric layer, the insulating layer, and the second wiring are stacked in this order, located on the second end side opposite to the first end in the piezoelectric layer. The liquid ejecting head according to claim 1, comprising a region. The liquid ejecting head according to claim 3, wherein a second pressure chamber end where the wall surface on the second end side of the piezoelectric layer in the pressure chamber intersects the diaphragm overlaps the third stacked region in a plan view. The end of the second pressure chamber is located in a region of the third stacked region where the first electrode, the piezoelectric layer, the second electrode, the insulating layer, and the second wiring are stacked in this order. The liquid jet head according to claim 3, wherein the liquid jet head overlaps in a plan view.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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