JP7404996B2 - Piezoelectric actuator and its manufacturing method - Google Patents

Description

The present invention relates to a piezoelectric actuator that includes a piezoelectric body having a plurality of piezoelectric layers and first to third electrodes, and in which the piezoelectric body has first to third active parts, and a method for manufacturing the piezoelectric actuator.

Patent Document 1 discloses a piezoelectric actuator that includes a piezoelectric body having a plurality of piezoelectric layers and first to third electrodes, and in which the piezoelectric body has first to third parts (first to third active parts of the present invention). By satisfying the following requirements (I) and (II), drive deterioration of the actuator part can be suppressed (specifically, as the number of deformations of the actuator part increases, the amount of deformation of the second part decreases). However, the amount of deformation of the third portion increases, and the amount of deformation of one actuator portion as a whole becomes stable.

Requirement (I): “The other end of the second portion (the second active portion of the present invention) is connected to the one end of the second portion and the first portion (the first active portion of the present invention) in the first direction. (For example, in FIG. 6 of Patent Document 1, the other end of the second active part 62 is located between one end of the second active part 62 and the first active part in the X direction. (In other words, the second active part 62 is spaced apart from the first active part 61 in one direction in the X direction.)

Requirement (II): “The one end of the third portion (the third active portion of the present invention)” is located in any of the following positions (a) to (c) (a) “In the first direction, A position between the one end of the first part (the first active part of the present invention) and the other end of the first part (for example, in FIG. 6 of Patent Document 1, one end of the second active part 63 is , in the X direction, is located between one end of the first active part 61 and the other end of the first active part 61. That is, the second active part 63 is located between the other end of the first active part 61 in the X direction. )
(b) "the same position in the first direction as the other end of the first part (first active part of the present invention)" (for example, in FIGS. 16(a) and (b) of Patent Document 1, One end of the second active section 63 is located at the same position as the other end of the first active section 61 in the X direction. That is, the second active section 63 is located at the same position as the other end of the first active section 61 in the X direction. adjacent in the direction).
(c) “A position between the other end of the first portion (the first active portion of the present invention) and the other end of the third portion (the third active portion of the present invention) in the first direction; The distance in the first direction from the other end of the first portion to the one end of the third portion is equal to the distance from the other end of the second portion to the one end of the first portion. 16(c) of Patent Document 1, one end of the second active part 63 is located between the other end 61b of the first active part 61 and the second active part 61 in the X direction. the other end 63b of the portion 63 (that is, the second active portion 63 is spaced apart from the first active portion 61 in the other direction in the X direction), and the second active portion 63 and the first active portion 61 in the X direction is shorter than the distance t2 in the X direction between the second active part 62 and the first active part 61.)

Japanese Patent Application Publication No. 2019-177562

When forming an electrode by screen printing using a squeegee, bleeding is likely to occur at the end of the electrode on the downstream side in the direction of movement of the squeegee, and the bleeding may form a thin portion.

In the configuration of Patent Document 1, if a thin wall portion is formed in the electrode, there may be a case where requirement (I) is not satisfied depending on the position where the thin wall portion is formed (for example, in FIG. 6 of Patent Document 1, The two active parts 62 and the first active part 61 may not be separated from each other in the X direction, but may be adjacent to each other in the X direction, or may partially overlap in the Z direction). In this case, since requirement (I) is not satisfied, as the number of deformations of the actuator section increases, not only the amount of deformation of the third active section but also the amount of deformation of the second active section increases, resulting in an increase in the amount of deformation of the second active section as a whole. The amount of deformation changes.

An object of the present invention is to provide a piezoelectric actuator and a method for manufacturing the same that can reliably satisfy the above requirement (I) even when a thin portion is formed in the electrode.

A piezoelectric actuator according to a first aspect of the present invention includes a piezoelectric body having a plurality of piezoelectric layers stacked in a first direction, a first electrode, and a second electrode separated from the first electrode in the first direction. , a third electrode separated from the first electrode in the first direction, the piezoelectric body being sandwiched between the first electrode and the second electrode in the first direction. a second active part sandwiched between the first electrode and the third electrode in the first direction; a second active part sandwiched between the first electrode and the third electrode in the first direction; a third active part spaced apart from the second active part in a second direction perpendicular to the first direction, the first active part being spaced apart from the second active part in the second direction; a portion disposed between the second active portion and the third active portion, the second active portion being spaced apart from the first active portion in one of the second directions; The part is located in any of the following positions (a) to (c),
(a) A position in the first active part overlapping the other end in the second direction and the first direction; (b) A position in the first active part overlapping the other end in the second direction and the second direction. (c) an adjacent position separated from the first active part in the other direction in the second direction, and the distance between the third active part and the first active part in the second direction is the same as that of the second active part; The second electrode has a second thick part and a second thin part that is smaller in thickness in the first direction than the second thick part. in the second direction, the second electrode has one end forming one end in the second direction of the first active part, and a second electrode in the first active part in the second direction. and the other end forming the other end of the second electrode, and the second thin part is formed at the other end of the second electrode and is not formed at the one end of the second electrode. shall be.

A piezoelectric actuator according to a second aspect of the present invention includes a piezoelectric body having a plurality of piezoelectric layers stacked in a first direction, a first electrode, and a second electrode separated from the first electrode in the first direction. , a third electrode separated from the first electrode in the first direction, the piezoelectric body being sandwiched between the first electrode and the second electrode in the first direction. a second active part sandwiched between the first electrode and the third electrode in the first direction; a second active part sandwiched between the first electrode and the third electrode in the first direction; a third active part spaced apart from the second active part in a second direction perpendicular to the first direction, the first active part being spaced apart from the second active part in the second direction; a portion disposed between the second active portion and the third active portion, the second active portion being spaced apart from the first active portion in one of the second directions; The part is located in any of the following positions (a) to (c),
(a) A position in the first active part overlapping the other end in the second direction and the first direction; (b) A position in the first active part overlapping the other end in the second direction and the second direction. (c) an adjacent position separated from the first active part in the other direction in the second direction, and the distance between the third active part and the first active part in the second direction is the same as that of the second active part; The third electrode has a third thick part and a third thin part that is smaller in thickness in the first direction than the third thick part. In the second direction, the third electrode has one end forming one end in the second direction of the third active part, and a second end in the second direction of the second active part. and the other end forming the other end of the third electrode, and the third thin part is formed at the one end of the third electrode and is not formed at the other end of the third electrode. shall be.

A method for manufacturing a piezoelectric actuator according to a third aspect of the present invention includes: a piezoelectric body having a plurality of piezoelectric layers stacked in a first direction; a first electrode; and a piezoelectric actuator separated from the first electrode in the first direction. A method for manufacturing a piezoelectric actuator comprising two electrodes, and a third electrode spaced apart from the first electrode in the first direction, the piezoelectric body including the first electrode and the third electrode in the first direction. a first active part sandwiched between two electrodes; a second active part sandwiched between the first electrode and the third electrode in the first direction; and a second active part sandwiched between the first electrode and the third electrode in the first direction. and a third active part sandwiched between three electrodes, the third active part being spaced apart from the second active part in a second direction perpendicular to the first direction, and the first active part is , a portion disposed between the second active part and the third active part in the second direction, the second active part being spaced apart from the first active part in one of the second directions. and the third active part is located in any of the following positions (a) to (c),
(a) A position in the first active part overlapping the other end in the second direction and the first direction; (b) A position in the first active part overlapping the other end in the second direction and the second direction. (c) an adjacent position separated from the first active part in the other direction in the second direction, and the distance between the third active part and the first active part in the second direction is the same as that of the second active part; A step of forming the second electrode by screen printing by moving a squeegee from one side to the other side in the second direction, the position being shorter than the distance from the first active part in the second direction. It is characterized by

A method for manufacturing a piezoelectric actuator according to a fourth aspect of the present invention includes: a piezoelectric body having a plurality of piezoelectric layers stacked in a first direction; a first electrode; and a piezoelectric actuator separated from the first electrode in the first direction. A method for manufacturing a piezoelectric actuator comprising two electrodes, and a third electrode spaced apart from the first electrode in the first direction, the piezoelectric body including the first electrode and the third electrode in the first direction. a first active part sandwiched between two electrodes; a second active part sandwiched between the first electrode and the third electrode in the first direction; and a second active part sandwiched between the first electrode and the third electrode in the first direction. and a third active part sandwiched between three electrodes, the third active part being spaced apart from the second active part in a second direction perpendicular to the first direction, and the first active part is , a portion disposed between the second active part and the third active part in the second direction, the second active part being spaced apart from the first active part in one of the second directions. and the third active part is located in any of the following positions (a) to (c),
(a) A position in the first active part overlapping the other end in the second direction and the first direction; (b) A position in the first active part overlapping the other end in the second direction and the second direction. (c) an adjacent position separated from the first active part in the other direction in the second direction, and the distance between the third active part and the first active part in the second direction is the same as that of the second active part; A step of forming the third electrode by screen printing by moving a squeegee from the other side to the one side in the second direction, the position being shorter than the distance from the first active part in the second direction. It is characterized by

1 is an overall configuration diagram of a printer 1 including a head 3 equipped with a piezoelectric actuator 22 according to a first embodiment of the present invention. 2 is a plan view of the head 3 of FIG. 1. FIG. 3 is a plan view showing three piezoelectric layers 41 to 43 in the piezoelectric actuator 22 of FIG. 2, respectively. FIG. FIG. 4 is a sectional view taken along the line IV-IV in FIGS. 2 and 3. FIG. FIG. 4 is a sectional view taken along line VV in FIGS. 2 and 3. FIG. 6 is a diagram showing the operation of the actuator section in the cross section of FIG. 5. FIG. 6 is a cross-sectional view corresponding to FIG. 5, showing a step of forming a high potential electrode 52 on the upper surface of the piezoelectric layer 42 by screen printing. FIG. 6 is a sectional view corresponding to FIG. 5 showing a piezoelectric actuator 222 according to a second embodiment of the present invention. FIG. FIG. 6 is a cross-sectional view corresponding to FIG. 5 showing piezoelectric actuators 322, 422, and 522 according to third to fifth embodiments of the present invention, respectively.

In the following description, the Z direction is a vertical direction, and the X and Y directions are horizontal directions. Both the X direction and the Y direction are perpendicular to the Z direction. The X direction is perpendicular to the Y direction. The Z direction corresponds to the "first direction" of the present invention, and the X direction corresponds to the "second direction" of the present invention.

<First embodiment>
First, with reference to FIG. 1, the overall configuration of a printer 1 including a head 3 including a piezoelectric actuator 22 according to a first embodiment of the present invention will be described.

The printer 1 includes a head 3, a carriage 2, and two pairs of transport rollers 4.

The carriage 2 is supported by two guide rails 5 extending in the Y direction, and is movable in the Y direction along the guide rails 5.

The head 3 is of a serial type, is mounted on the carriage 2, and is movable together with the carriage 2 in the Y direction. A plurality of nozzles 15 are opened on the lower surface of the head 3 (the surface facing downward in the Z direction).

The two transport roller pairs 4 are arranged with the carriage 2 in between in the X direction. Under the control of a control unit (not shown) of the printer 1, the pair of transport rollers 4 rotates while sandwiching the paper P, so that the paper P is transported in the transport direction along the X direction.

The control unit alternately performs an ejection operation in which ink is ejected from the nozzle 15 while moving the head 3 together with the carriage 2 in the Y direction, and a transport operation in which the paper P is transported by a predetermined amount in the transport direction by the transport roller pair 4. let As a result, an image is recorded on the paper P.

Next, the configuration of the head 3 will be explained with reference to FIGS. 2 to 7.

The head 3 includes a flow path unit 21, a piezoelectric actuator 22, and a COF (Chip On Film) 23, as shown in FIG.

The flow path unit 21 has a rectangular shape when viewed from the Z direction, and has two sides 21a and 21b along the Y direction and two sides 21c and 21d along the X direction.

Like the flow path unit 21, the piezoelectric actuator 22 has a rectangular shape when viewed from the Z direction, and has two sides 22a and 22b along the Y direction and two sides 22c and 22d along the X direction. The piezoelectric actuator 22 is one size smaller than the flow path unit 21 when viewed from the Z direction.

As shown in FIG. 4, the flow path unit 21 is composed of four plates 31 to 34 stacked in the Z direction.

A plurality of pressure chambers 10 are formed in the plate 31. As shown in FIG. 2, each pressure chamber 10 has a substantially rectangular shape when viewed from the Z direction, and the length in the Y direction is longer than the length in the X direction. The plurality of pressure chambers 10 form four pressure chamber rows 9. The four pressure chamber rows 9 are arranged in the Y direction. Each pressure chamber row 9 is composed of eight pressure chambers 10 arranged at equal intervals in the X direction.

As shown in FIG. 4, through holes 12 and 13 are formed in the plate 32 for each pressure chamber 10. The through holes 12 and 13 overlap in the Z direction with one end 10c in the Y direction and the other end 10d in the Y direction of the corresponding pressure chamber 10, respectively. The through hole 12 has a cross-sectional area perpendicular to the Z direction that is smaller than a cross-sectional area of the pressure chamber 10 perpendicular to the Y direction, and functions as a throttle flow path.

As shown in FIG. 4, a through hole 14 is formed in the plate 33 for each through hole 13. The through holes 14 overlap the corresponding through holes 13 in the Z direction.

As shown in FIG. 4, the plate 33 is further formed with four manifold channels 11. The four manifold channels 11 correspond to each of the four pressure chamber rows 9, as shown in FIG. Each manifold channel 11 extends in the X direction and has a portion that overlaps with the eight pressure chambers 10 of the corresponding pressure chamber row 9 in the Z direction. Each manifold flow path 11 communicates with eight pressure chambers 10 of the corresponding pressure chamber row 9 via through holes 12 .

On the upper surface of the plate 31, four ink supply ports 8 are formed in an area where the piezoelectric actuator 22 is not arranged (see FIG. 2). The four ink supply ports 8 correspond to the four manifold channels 11, respectively. Each ink supply port 8 is located at a position overlapping one end of the corresponding manifold channel 11 in the X direction (lower end in FIG. 2) in the Z direction. Ink is supplied from the four ink supply ports 8 to each of the four manifold channels 11.

As shown in FIG. 4, a plurality of nozzles 15 are formed through the plate 34. As shown in FIG. Each of the plurality of nozzles 15 overlaps the through hole 14 in the Z direction. The nozzle 15 communicates with the pressure chamber 10 via the through holes 13 and 14.

The ink supplied to each manifold channel 11 flows upward in the Z direction through the through hole 12 and flows into the pressure chamber 10 . The ink flows in the pressure chamber 10 along the Y direction from one end 10c to the other end 10d, flows through the through holes 13 and 14 downward in the Z direction, and is discharged from the nozzle 15.

As shown in FIG. 4, the piezoelectric actuator 22 is located above the channel unit 21 in the Z direction and is fixed to the upper surface of the plate 31.

The piezoelectric actuator 22 includes a piezoelectric body 40 , an ink separation layer 44 , a plurality of drive electrodes 51 , a high potential electrode 52 , and a low potential electrode 53 . The drive electrode 51 corresponds to the "first electrode" of the present invention, the high potential electrode 52 corresponds to the "second electrode" of the present invention, and the low potential electrode 53 corresponds to the "third electrode" of the present invention.

The piezoelectric body 40 includes three piezoelectric layers 41 to 43 stacked in the Z direction. The piezoelectric layers 41 to 43 and the ink separation layer 44 have the same shape and size when viewed from the Z direction, and define the outer shape of the rectangular piezoelectric actuator 22 shown in FIG. 2.

The ink separation layer 44 is arranged on the upper surface of the plate 31 and covers all the pressure chambers 10 formed in the plate 31, as shown in FIG. The ink separation layer 44 is made of, for example, a metal material such as stainless steel, a piezoelectric material containing lead zirconate titanate as a main component, a synthetic resin material, or the like.

The piezoelectric layer 43 is placed on the top surface of the ink separation layer 44 . Piezoelectric layer 42 is arranged on the top surface of piezoelectric layer 43. Piezoelectric layer 41 is placed on the top surface of piezoelectric layer 42 . The piezoelectric layers 41 to 43 are made of a piezoelectric material containing lead zirconate titanate as a main component.

The plurality of drive electrodes 51, high potential electrodes 52, and low potential electrodes 53 are spaced apart from each other in the Z direction. Specifically, a plurality of drive electrodes 51, high potential electrodes 52, and low potential electrodes 53 are arranged in order from the top in the Z direction.

As shown in FIG. 3A, the plurality of drive electrodes 51 are arranged on the upper surface of the piezoelectric layer 41, and are provided corresponding to each of the plurality of pressure chambers 10. That is, like the plurality of pressure chambers 10, the plurality of drive electrodes 51 form four rows each consisting of eight drive electrodes 51 arranged at equal intervals in the X direction. Each drive electrode 51 includes a portion that overlaps with the corresponding pressure chamber 10 in the Z direction and a portion that does not overlap with the corresponding pressure chamber 10 in the Z direction. In each drive electrode 51, the non-overlapping portion is located on one side in the X direction (lower in FIG. 3(a)) with respect to the overlapping portion.

In each drive electrode 51, a contact point electrically connected to the wiring of the COF 23 (see FIG. 2) is provided in the non-overlapping portion. The driver IC 24 mounted on the COF 23 individually applies either a high potential (VDD potential) or a low potential (GND potential) to the plurality of drive electrodes 51 via the wiring of the COF 23 .

As shown in FIG. 3(b), the high potential electrode 52 is arranged on the upper surface of the piezoelectric layer 42, and has a plurality of individual parts 52a, four connecting parts 52b, a connecting part 52c, and a lead-out part 52d. . The plurality of individual parts 52a are provided corresponding to each of the plurality of pressure chambers 10. Each individual portion 52a overlaps the corresponding pressure chamber 10 in the Z direction. The four connection parts 52b are provided corresponding to each of the four pressure chamber rows 9. Each connecting portion 52b extends in the X direction and connects one end in the Y direction (the right end in FIG. 3(b)) of the individual portion 52a corresponding to each of the eight pressure chambers 10 of the pressure chamber row 9. There is. The connecting portion 52c extends in the Y direction and connects one end of the four connecting portions 52b in the X direction (lower end in FIG. 3(b)). The pull-out portion 52d is drawn out from the other end of the connecting portion 52c in the Y direction (the left end in FIG. 3(b)) to the other end in the X direction (upward in FIG. 3(b)). The direction in which the drawer portion 52d extends from the connecting portion 52c is the same as the direction in which each connecting portion 52b extends from the connecting portion 52c. The lead-out portion 52d is connected to the surface electrode 72 via a through hole 41x (see FIG. 3(a)) formed in the piezoelectric layer 41. The surface electrode 72 is arranged on the upper surface of the piezoelectric layer 41, and overlaps the lead-out portion 52d in the Z direction.

The surface electrode 72 is electrically connected to the wiring of the COF 23 (see FIG. 2). The driver IC 24 applies a high potential (VDD potential) to the high potential electrode 52 via the wiring of the COF 23 .

The low potential electrode 53 is arranged on the upper surface of the piezoelectric layer 43, as shown in FIG. . An individual portion 53a is arranged between two pressure chambers 10 adjacent to each other in the X direction. Further, an individual portion 53a is arranged between the side 22a of the piezoelectric actuator 22 and the pressure chamber 10 adjacent to the side 22a in the X direction. Among the plurality of individual parts 53a, the individual parts 53a excluding the four individual parts 53a located at one end in the X direction (lower end in FIG. 3(c)) are connected to two pressure chambers 10 adjacent to each other in the X direction. It has a portion that straddles and overlaps the two pressure chambers 10 in the Z direction. Each of the four individual portions 53a has a portion that overlaps in the Z direction with the side 22a and the pressure chamber 10 adjacent in the X direction. The four connection parts 53b are provided corresponding to each of the four pressure chamber rows 9. Each connecting portion 53b extends in the X direction, and connects the other end (left end in FIG. 3(c)) of the individual portion 53a in the Y direction corresponding to each of the eight pressure chambers 10 of the pressure chamber row 9. ing. The connecting portion 53c extends in the Y direction and connects the other ends of the four connecting portions 53b in the X direction (the upper ends in FIG. 3(c)). The connecting portion 53c has a portion that overlaps in the Z direction with each of the four pressure chambers 10 adjacent to the side 22b of the piezoelectric actuator 22 in the X direction. The pull-out portion 53d is pulled out from the other end of the connecting portion 53c in the Y direction (the left end in FIG. 3(c)) to one side in the X direction (downward in FIG. 3(c)). The direction in which the drawer portion 53d extends from the connecting portion 53c is the same as the direction in which each connecting portion 53b extends from the connecting portion 53c. The lead-out portion 53d connects to the surface electrode 73 through a through hole 41y formed in the piezoelectric layer 41 (see FIG. 3(a)) and a through hole 42y formed in the piezoelectric layer 42 (see FIG. 3(b)). It is connected. The surface electrode 73 is arranged on the upper surface of the piezoelectric layer 41 and overlaps the lead-out portion 53d in the Z direction.

The surface electrode 73 is electrically connected to the wiring of the COF 23 (see FIG. 2). The driver IC 24 applies a low potential (GND potential) to the low potential electrode 53 via the wiring of the COF 23 .

As shown in FIGS. 4 and 5, the portion of the piezoelectric layer 41 sandwiched between the drive electrode 51 and the high potential electrode 52 in the Z direction is referred to as a "first active portion 61." The portions of the piezoelectric layers 41 and 42 sandwiched between the drive electrode 51 and the low potential electrode 53 in the Z direction are referred to as a "second active part 62" and a "third active part 63." The first active part 61 is mainly polarized upward, and the second active part 62 and the third active part 63 are mainly polarized downward.

The piezoelectric actuator 22 has an actuator section 60 that includes a first active section 61 , a second active section 62 , and a third active section 63 for each pressure chamber 10 .

The second active section 62 and the third active section 63 have a function of suppressing crosstalk. Crosstalk refers to a phenomenon in which pressure fluctuations due to deformation of the actuator section 60 in a certain pressure chamber 10 are transmitted to another pressure chamber 10 adjacent to the pressure chamber 10 in the X direction.

Hereinafter, with reference to FIG. 5, the positional relationship between the active parts 61 to 63 in one actuator part 60, the positional relationship between the active parts 61 to 63 in one actuator part 60 and the corresponding pressure chamber 10, etc. will be explained. do.

The first active portion 61 overlaps in the Z direction with a substantially central region of the pressure chamber 10 in the X direction, and does not have a portion that does not overlap with the pressure chamber 10 in the Z direction. The second active part 62 and the third active part 63 are separated from each other in the X direction. The first active section 61 has a portion disposed between the second active section 62 and the third active section 63 in the X direction.

The second active part 62 has a part that is separated from the first active part 61 in one direction in the X direction (the left side in FIG. 5) and overlaps in the Z direction with one end in the X direction (the left end in FIG. 5) of the pressure chamber 10; It has a portion that does not overlap with the pressure chamber 10 in the Z direction.

The third active portion 63 overlaps in the Z direction with a region between the center of the pressure chamber 10 in the X direction and the other end (the right end in FIG. 5), and has a portion that does not overlap with the pressure chamber 10 in the Z direction. Not yet. The third active portion 63 overlaps the other end of the first active portion 61 in the X direction (the right end in FIG. 5) in the Z direction.

Next, with reference to FIG. 6, the operation of the actuator section 60 corresponding to a certain nozzle 15 when ink is ejected from the nozzle 15 will be described.

Before the printer 1 starts the recording operation, a low potential (GND potential) is applied to each drive electrode 51, as shown in FIG. 6(a). At this time, in each actuator section 60, an upward electric field equal to the polarization direction is generated in the first active section 61 due to the potential difference between the drive electrode 51 and the high potential electrode 52, and the first active section 61 is and the direction along the Y direction). As a result, a portion of the laminate including the piezoelectric body 40 and the ink separation layer 44 that overlaps the pressure chamber 10 in the Z direction is bent so as to be convex (downward) toward the pressure chamber 10 . At this time, the volume of the pressure chamber 10 is smaller than that in the case where the laminate is flat.

When the printer 1 starts a recording operation and ink is ejected from a certain nozzle 15, first, as shown in FIG. ) to a high potential (VDD potential). At this time, in the actuator section 60, the potential difference between the drive electrode 51 and the high potential electrode 52 disappears, so that the contraction of the first active section 61 is eliminated. On the other hand, due to the potential difference between the drive electrode 51 and the low potential electrode 53, a downward electric field is generated in the second active part 62 and the third active part 63, which is equal to the polarization direction of the second active part 62 and the third active part 63. The portion 63 contracts in the plane direction. However, the second active section 62 and the third active section 63 have a crosstalk suppressing function as described above, and hardly contribute to the deformation of the actuator section 60. That is, at this time, the laminate does not bend so that the portion overlapping with the pressure chamber 10 in the Z direction becomes convex in the direction away from the pressure chamber 10 (upward), but becomes flat. As a result, the volume of the pressure chamber 10 becomes larger than that in FIG. 6(a).

Thereafter, as shown in FIG. 6A, the potential of the drive electrode 51 corresponding to the nozzle 15 is switched from a high potential (VDD potential) to a low potential (GND potential). At this time, in the actuator section 60, the potential difference between the drive electrode 51 and the low potential electrode 53 is eliminated, so that the contraction of the second active section 62 and the third active section 63 is eliminated. On the other hand, due to the potential difference between the drive electrode 51 and the high potential electrode 52, an upward electric field equal to the polarization direction is generated in the first active part 61, and the first active part 61 contracts in the planar direction. As a result, the portion of the laminate that overlaps the pressure chamber 10 in the Z direction is bent so as to be convex (downward) toward the pressure chamber 10 . At this time, since the volume of the pressure chamber 10 is greatly reduced, a large pressure is applied to the ink within the pressure chamber 10, and the ink is ejected from the nozzle 15.

There is a concern that the amount of deformation of the actuator section 60 will decrease (that is, drive deterioration) due to repeated operations of the actuator section 60. However, in the present embodiment, drive deterioration of the actuator section 60 can be suppressed by satisfying the following requirements (I) and (II-a).

Requirement (I): The second active part 62 is separated from the first active part 61 in one direction in the X direction (left side in FIG. 5).

Requirement (II-a): The third active portion 63 overlaps the other end of the first active portion 61 in the X direction (the right end in FIG. 5) in the Z direction.

Specifically, as shown in Japanese Patent Application Laid-open No. 2019-177562, by satisfying the above requirements (I) and (II-a), the second activation Although the amount of deformation of the portion 62 may decrease, the amount of deformation of the third active portion 63 increases, and the amount of deformation of one actuator portion 60 as a whole becomes stable.

Here, the piezoelectric actuator 22 of this embodiment is manufactured by sequentially forming piezoelectric layers 41 to 43 and electrodes 51 to 53 on the upper surface of the ink separation layer 44 (see FIG. 5). Each electrode 51 to 53 is formed by screen printing using a squeegee. In this case, bleeding is likely to occur at the end on the downstream side in the moving direction of the squeegee, and the bleeding may be formed as thin portions 51s, 52s, and 53s (see FIG. 5).

For example, when forming the high potential electrode 52, as shown in FIG. Then, a high potential electrode 52 is formed by screen printing. At this time, the squeegee 100 moves while holding the electrode material (for example, silver, nickel, gold, etc.) 110 on the downstream side in the moving direction D. The high potential electrode 52 is formed by the material 110 entering the hole 101x. At this time, the material 110 flows into the downstream end of the high potential electrode 52 in the moving direction D, which tends to cause bleeding A. This bleeding A is formed as the thin portion 52s.

In this way, the high potential electrode 52 has a thick portion 52t corresponding to the hole 101x of the mask 101, and a thin portion 52s located downstream in the moving direction D with respect to the thick portion 52t. The thin portion 52s has a smaller thickness in the Z direction than the thick portion 52t.

The same applies to the drive electrode 51 and the low potential electrode 53, and as shown in FIG. 51s and 53s. The thin parts 51s and 53s have a smaller thickness in the Z direction than the thick parts 51t and 53t.

The thick part 51t corresponds to the "first thick part" of the present invention, and the thin part 51s corresponds to the "first thin part" of the present invention. The thick part 52t corresponds to the "second thick part" of the present invention, and the thin part 52s corresponds to the "second thin part" of the present invention. The thick part 53t corresponds to the "33rd thick part" of the present invention, and the thin part 53s corresponds to the "third thin part" of the present invention.

For example, the thickness of the thick portions 51t to 53t in the Z direction is approximately 1 μm, and the thickness of the thin portions 51s to 53s in the Z direction is 0.1 μm or less. Further, the length of the thin portions 51s to 53s in the X direction is, for example, 10 to 100 μm, which is greater than the distance S between the second active portion 62 and the first active portion 61 in the X direction.

In this embodiment, the moving direction D of the squeegee 100 when forming the drive electrode 51 is a direction from the other side (right side in FIG. 5) to one side (left side in FIG. 5) in the X direction. Therefore, the thin portion 51s is located on one side in the X direction (left side in FIG. 5) with respect to the thick portion 51t.

In the X direction, the drive electrode 51 has one end 51x forming one end in the X direction of the second active part 62 (the left end in FIG. 5) and the other end 51y forming the right end of 5. The thin portion 51s is formed at one end 51x and not formed at the other end 51y. The thin portion 51s is arranged in a portion that does not overlap the pressure chamber 10 in the Z direction.

The moving direction D of the squeegee 100 is the same for all drive electrodes 51. Therefore, in all the drive electrodes 51, the thin portions 51s are arranged on the same side in the X direction with respect to the thick portions 51t.

When forming the high potential electrode 52, the moving direction D of the squeegee 100 is a direction from one side of the X direction (left side in FIG. 5) to the other side (right side in FIG. 5). Therefore, the thin portion 52s is located on the other side of the thick portion 52t in the X direction (to the right in FIG. 5).

In the X direction, the individual portion 52a of the high potential electrode 52 has one end 52ax forming one end in the X direction (the left end in FIG. 5) of the first active portion 61, and the other end in the X direction of the first active portion 61. (the right end in FIG. 5) and the other end 52ay. The thin portion 52s is formed at the other end 52ay, and is not formed at the one end 52ax.

The moving direction D of the squeegee 100 is the same in all the individual parts 52a. Therefore, for each of the plurality of drive electrodes 51, the thin portion 52s is arranged on the same side in the X direction as the thick portion 52t.

When forming the low potential electrode 53, the moving direction D of the squeegee 100 is from the other side (right side in FIG. 5) to the other side (left side in FIG. 5) in the X direction. Therefore, the thin portion 53s is located on one side in the X direction (left side in FIG. 5) with respect to the thick portion 53t.

In the X direction, the individual portion 53a of the low potential electrode 53 has one end 53ax forming one end in the X direction (the left end in FIG. 5) of the third active portion 63, and the other end in the X direction of the second active portion 62. (the right end in FIG. 5) and the other end 53ay. The thin portion 53s is formed at one end 53ax and not formed at the other end 53ay.

The moving direction D of the squeegee 100 is the same in all the individual parts 53a. Therefore, for each of the plurality of drive electrodes 51, the thin portion 53s is arranged on the same side in the X direction as the thick portion 53t.

In this embodiment, as shown in FIG. 5, the end portion of the thick portion 52t of the individual portion 52a to which the thin portion 52s connects and the end portion of the thick portion 53t of the individual portion 53a to which the thin portion 53s connects. , are at the same position in the X direction. The thick portion 52t and the thick portion 53t do not overlap each other in the Z direction, but are adjacent to each other in the X direction. The thin portion 52s overlaps the thick portion 53t in the Z direction, and the thin portion 53s overlaps the thick portion 52t in the Z direction.

As described above, according to the piezoelectric actuator 22 of this embodiment, in the individual portion 52a of the high potential electrode 52, the thin portion 52s is formed at the other end 52ay, and is not formed at the one end 52ax (FIG. reference). The method for manufacturing the piezoelectric actuator 22 of this embodiment includes a step of moving a squeegee 100 from one side in the X direction toward the other (right side in FIG. 5) and forming the high potential electrode 52 by screen printing. (See Figure 7). When the thin portion 52s is formed at one end 52ax, the first active portion 61 becomes longer in the direction approaching the second active portion 62. In this case, the second active part 62 and the first active part 61 are not separated from each other in the X direction, but are adjacent to each other in the X direction, or overlap in the Z direction, so that requirement (I) may not be satisfied. On the other hand, in the present embodiment, since the thin portion 52s is formed at the other end 52ay and not at the one end 52ax, the first active portion 61 does not become longer in the direction approaching the second active portion 62, and the above-mentioned requirements are met. (I) can be certainly satisfied.

According to the piezoelectric actuator 22 of this embodiment, in the individual portion 53a of the low potential electrode 53, the thin portion 53s is formed at one end 53ax and not formed at the other end 53ay (see FIG. 5). The method for manufacturing the piezoelectric actuator 22 of this embodiment includes a step of moving a squeegee 100 from the other side toward one side (left side in FIG. 5) in the X direction and forming the low potential electrode 53 by screen printing. . When the thin portion 53s is formed at the other end 53ay, the second active portion 62 becomes longer in the direction approaching the first active portion 61. In this case, the second active part 62 and the first active part 61 are not separated from each other in the X direction, but are adjacent to each other in the X direction, or overlap in the Z direction, so that requirement (I) may not be satisfied. On the other hand, in this embodiment, since the thin portion 53s is formed at one end 53ax and not at the other end 53ay, the second active portion 62 does not become longer in the direction approaching the first active portion 61, and the requirements ( I) can be definitely satisfied.

In a configuration that satisfies requirement (II-a) [requirement that the third active portion 63 overlaps the other end in the X direction (the right end in FIG. 5) of the first active portion 61 in the Z direction], the thick portion 52t, 53t are adjacent to each other in the X direction without overlapping in the Z direction, the thin part 52s overlaps with the thick part 53t in the Z direction, and the thin part 53s overlaps with the thick part 52t in the Z direction (see FIG. 5). . When the thick portions 52t and 53t overlap in the Z direction, the rigidity of the portions increases, and deformation of the actuator portion 60 may be inhibited. On the other hand, in this embodiment, since the thick portions 52t and 53t do not overlap in the Z direction, the increase in rigidity as described above can be suppressed, and inhibition of deformation of the actuator section 60 can be suppressed.

In the drive electrode 51, the thin portion 51s is formed at one end 51x and not formed at the other end 51y (see FIG. 5). It is assumed that the piezoelectric actuator 22 of this embodiment is fixed to the flow path unit 21 so that one end 51x does not overlap with the pressure chamber 10 in the Z direction, and the other end 51y overlaps with the pressure chamber 10 in the Z direction. Ru. In this case, if the thin portion 51s is formed at the other end 51y, the rigidity of the portion overlapping with the pressure chamber 10 in the Z direction is increased, and deformation of the actuator portion 60 may be inhibited. On the other hand, in the present embodiment, since the thin wall portion 51s is formed at one end 51x and not at the other end 51y, the stiffness of the portion overlapping with the pressure chamber 10 in the Z direction is suppressed from increasing, and the actuator portion 60 can be prevented from deforming.

The distance S between the second active portion 62 and the first active portion 61 in the X direction is equal to or less than the length of the thin portion 52s in the X direction (see FIG. 5). In this case, if the thin portion 52s is formed at one end 52ax, the spacing S will be filled by the thin portion 52s, increasing the possibility that requirement (I) will not be satisfied. However, in this embodiment, since the thin portion 52s is formed not at the end 52ax but at the other end 52ay, the problem that requirement (I) is not satisfied can be suppressed.

The distance S between the second active part 62 and the first active part 61 in the X direction is equal to or less than the length of the thin part 53s in the X direction (see FIG. 5). In this case, if the thin portion 53s is formed at the other end 53ay, the spacing S will be filled by the thin portion 53s, increasing the possibility that requirement (I) will not be satisfied. However, in this embodiment, since the thin portion 53s is formed not at the other end 53ay but at one end 53ax, the problem that requirement (I) is not satisfied can be suppressed.

For each of the plurality of drive electrodes 51, the thin part 52s is arranged on the same side in the X direction (the arrangement direction of the drive electrodes 51) with respect to the thick part 52t. In this case, in the plurality of actuator sections 60 arranged in the X direction, the active sections 61 to 63 are arranged in the same manner. Thereby, variations in deformation characteristics among the plurality of actuator sections 60 arranged in the X direction can be suppressed.

For each of the plurality of drive electrodes 51, the thin wall portion 53s is arranged on the same side of the thick wall portion 53t in the X direction (the direction in which the drive electrodes 51 are arranged). In this case, similarly to the above, the active parts 61 to 63 are arranged in the same manner in the plurality of actuator parts 60 arranged in the X direction. Thereby, variations in deformation characteristics among the plurality of actuator sections 60 arranged in the X direction can be suppressed.

<Second embodiment>
Next, with reference to FIG. 8, a piezoelectric actuator 222 according to a second embodiment of the present invention will be described.

In the first embodiment (FIG. 5), requirement (II-a) [requirement that the third active section 63 overlaps the other end of the first active section 61 in the X direction (the right end in FIG. 5) in the Z direction] In a configuration that satisfies the above, the thick portions 52t and 53t do not overlap in the Z direction but are adjacent to each other in the X direction, the thin portion 52s overlaps the thick portion 53t in the Z direction, and the thin portion 53s overlaps the thick portion 52t in the Z direction. overlap in the direction. On the other hand, in the second embodiment (FIG. 8), in a configuration that satisfies requirement (II-a), the thick portions 52t and 53t are separated from each other in the X direction, and the thin portion 52s and the thin portion 53s are separated from each other in the X direction. The thick portions 52t and 53t overlap each other in the Z direction.

In this embodiment, as in the first embodiment, the thick portions 52t and 53t do not overlap in the Z direction, so that inhibition of deformation of the actuator section 60 can be suppressed. Furthermore, in this embodiment, by employing a configuration in which the thin portions 52s and 53s overlap in the Z direction, increase in rigidity can be more reliably suppressed, and inhibition of deformation of the actuator portion 60 can be further suppressed.

<Third embodiment>
Next, a piezoelectric actuator 322 according to a third embodiment of the present invention will be described with reference to FIG. 9(a).

In the first embodiment (FIG. 5), requirement (II-a) [requirement that the third active section 63 overlaps the other end of the first active section 61 in the X direction (the right end in FIG. 5) in the Z direction] A configuration that satisfies the following is adopted. On the other hand, in the third embodiment (FIG. 9(a)), requirement (II-b) [the third active portion 63 is located at the other end of the first active portion 61 in the X direction (in FIG. 9(a) A configuration that satisfies the requirement of being adjacent to the right end) in the X direction is adopted. That is, in the third embodiment, the third active section 63 does not have a portion that overlaps with the first active section 61 in the Z direction, and is adjacent to the first active section 61 in the X direction.

In the third embodiment (FIG. 9A), the positions of the high potential electrode 52 and the low potential electrode 53 in the Z direction are opposite to those in the first embodiment (FIG. 5). In the third embodiment (FIG. 9(a)), a drive electrode 51, a low potential electrode 53, and a high potential electrode 52 are arranged in order from the top in the Z direction.

In the third embodiment (FIG. 9(a)), similarly to the first embodiment (FIG. 5), in the individual portion 52a of the high potential electrode 52, the thin portion 52s is formed at the other end 52ay and at one end 52ax. It has not been. In the individual portion 53a of the low potential electrode 53, the thin portion 53s is formed at one end 53ax and not formed at the other end 53ay.

In the third embodiment (FIG. 9(a)), the thick portions 52t and 53t do not overlap in the Z direction but are separated in the X direction. The thin parts 52s and 53s do not overlap in the Z direction but are adjacent to each other in the X direction.

In the third embodiment (FIG. 9(a)), when the thin portion 52s is formed at the end 52ax, the first active portion 61 becomes longer in the direction approaching the second active portion 62. In this case, the second active part 62 and the first active part 61 are not separated from each other in the X direction, but are adjacent to each other in the X direction, or overlap in the Z direction, so that requirement (I) may not be satisfied. On the other hand, in the third embodiment, since the thin portion 52s is formed at the other end 52ay and not at the one end 52ax, the first active portion 61 does not lengthen in the direction approaching the second active portion 62, and the Requirement (I) can be certainly satisfied.

Further, when the thin portion 53s is formed at the other end 53ay, the second active portion 62 becomes longer in the direction approaching the first active portion 61. In this case, the second active part 62 and the first active part 61 are not separated from each other in the X direction, but are adjacent to each other in the X direction, or overlap in the Z direction, so that requirement (I) may not be satisfied. On the other hand, in the third embodiment, since the thin part 53s is formed at one end 53ax and not at the other end 53ay, the second active part 62 does not become longer in the direction approaching the first active part 61, and the thin part 53s is not formed at the other end 53ay. (I) can be certainly satisfied.

<Fourth embodiment>
Next, a piezoelectric actuator 422 according to a fourth embodiment of the present invention will be described with reference to FIG. 9(b).

In the fourth embodiment (FIG. 9(b)), as in the third embodiment (FIG. 9(a)), the requirement (II-b) [the third active portion 63 is the other side of the first active portion 61 in the A configuration is adopted that satisfies the requirement that the end portion (the right end in FIG. 9(b)) be adjacent to the X direction. That is, in the fourth embodiment (FIG. 9(b)), similarly to the third embodiment (FIG. 9(a)), the third active portion 63 has a portion that overlaps with the first active portion 61 in the Z direction. First, it is adjacent to the first active part 61 in the X direction.

In the fourth embodiment (FIG. 9(b)), the positions of the drive electrode 51 and the high potential electrode 52 in the Z direction are opposite to those in the first embodiment (FIG. 5). In the fourth embodiment (FIG. 9(b)), a high potential electrode 52, a drive electrode 51, and a low potential electrode 53 are arranged in order from the top in the Z direction.

In the fourth embodiment (FIG. 9(b)), similarly to the first embodiment (FIG. 5), in the individual portion 52a of the high potential electrode 52, the thin portion 52s is formed at the other end 52ay and at one end 52ax. It has not been. In the individual portion 53a of the low potential electrode 53, the thin portion 53s is formed at one end 53ax and not formed at the other end 53ay.

In the fourth embodiment (FIG. 9(b)), similarly to the third embodiment (FIG. 9(a)), the thick portions 52t and 53t do not overlap in the Z direction but are separated in the X direction. . The thin parts 52s and 53s do not overlap in the Z direction but are adjacent to each other in the X direction.

In the fourth embodiment (FIG. 9(b)), when the thin portion 52s is formed at the end 52ax, the first active portion 61 becomes longer in the direction approaching the second active portion 62. In this case, the second active part 62 and the first active part 61 are not separated from each other in the X direction, but are adjacent to each other in the X direction, or overlap in the Z direction, so that requirement (I) may not be satisfied. On the other hand, in the fourth embodiment, since the thin part 52s is formed at the other end 52ay and not at the one end 52ax, the first active part 61 does not become longer in the direction approaching the second active part 62, and the above-mentioned Requirement (I) can be certainly satisfied.

Further, when the thin portion 53s is formed at the other end 53ay, the second active portion 62 becomes longer in the direction approaching the first active portion 61. In this case, the second active part 62 and the first active part 61 are not separated from each other in the X direction, but are adjacent to each other in the X direction, or overlap in the Z direction, so that requirement (I) may not be satisfied. On the other hand, in the fourth embodiment, since the thin part 53s is formed at one end 53ax and not at the other end 53ay, the second active part 62 is not elongated in the direction approaching the first active part 61, and the thin part 53s is not formed at the other end 53ay. (I) can be certainly satisfied.

<Fifth embodiment>
Next, a piezoelectric actuator 522 according to a fifth embodiment of the present invention will be described with reference to FIG. 9(c).

In the first embodiment (FIG. 5), requirement (II-a) [requirement that the third active section 63 overlaps the other end of the first active section 61 in the X direction (the right end in FIG. 5) in the Z direction] A configuration that satisfies the following is adopted. On the other hand, in the fifth embodiment (FIG. 9(c)), the requirement (II-c) [the third active portion 63 is separated from the first active portion 61 in the other direction in the X direction, and the third active portion 63 and the first active section 61 is shorter than the interval S2 in the X direction between the second active section 62 and the first active section 61. In the fifth embodiment (FIG. 9(c)), the third active part 63 does not have a portion that overlaps with the first active part 61 in the Z direction, and is separated from the first active part 61 in the X direction.

In the fifth embodiment (FIG. 9(c)), the lowest piezoelectric layer 43 in the first embodiment (FIG. 5) is omitted, and the piezoelectric body 40 consists of two piezoelectric layers 41 laminated in the Z direction. , 42.

In the fifth embodiment (FIG. 9(c)), similarly to the first embodiment (FIG. 5), in the individual portion 52a of the high potential electrode 52, the thin portion 52s is formed at the other end 52ay and at one end 52ax. It has not been. In the individual portion 53a of the low potential electrode 53, the thin portion 53s is formed at one end 53ax and not formed at the other end 53ay.

In the fifth embodiment (FIG. 9(c)), the thick portions 52t and 53t do not overlap in the Z direction but are spaced apart in the X direction. The thin parts 52s and 53s do not overlap in the Z direction but are separated in the X direction.

In the fifth embodiment (FIG. 9(c)), when the thin portion 52s is formed at the end 52ax, the first active portion 61 becomes longer in the direction approaching the second active portion 62. In this case, the second active part 62 and the first active part 61 are not separated from each other in the X direction, but are adjacent to each other in the X direction, or overlap in the Z direction, so that requirement (I) may not be satisfied. On the other hand, in the fifth embodiment, since the thin portion 52s is formed at the other end 52ay and not at the one end 52ax, the first active portion 61 does not become longer in the direction approaching the second active portion 62, and the Requirement (I) can be certainly satisfied.

Further, when the thin portion 53s is formed at the other end 53ay, the second active portion 62 becomes longer in the direction approaching the first active portion 61. In this case, the second active part 62 and the first active part 61 are not separated from each other in the X direction, but are adjacent to each other in the X direction, or overlap in the Z direction, so that requirement (I) may not be satisfied. On the other hand, in the fifth embodiment, since the thin part 53s is formed at one end 53ax and not at the other end 53ay, the second active part 62 is not elongated in the direction approaching the first active part 61, and the thin part 53s is not formed at the other end 53ay. (I) can be certainly satisfied.

<Modified example>
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made within the scope of the claims.

In the first embodiment, the moving direction D of the squeegee 100 when forming the drive electrodes 51 is the same for all the drive electrodes 51, but is not limited to this (the same applies to the high potential electrodes 52 and the low potential electrodes 53). ). For example, the moving direction of the squeegee 100 may be made different for each row of electrodes 51 to 53 (row corresponding to the pressure chamber row 9 shown in FIG. 2). Even in this case, the thin parts 51 to 53s and the thick parts 51t to 53t have the same positional relationship within the row, and the active parts 61 to 63 have the same arrangement, so that the plurality of Variations in deformation characteristics in the actuator section 60 can be suppressed.

The distance in the second direction between the second active part 62 and the first active part 61 (distance S in FIG. 5) is the same as the distance between the thin part 52s (second thin part) and the thin part 53s (third thin part) in the second direction. may exceed the length of

In the piezoelectric actuator according to the present invention, "the second thin part is formed at the other end of the second electrode and not formed at one end of the second electrode" and "the third thin part is formed at one end of the third electrode". It is sufficient to satisfy at least one of the following conditions: 1. The third electrode is formed at the other end of the third electrode and not formed at the other end of the third electrode, and is not limited to satisfying both conditions.

The first active portion may include a portion that does not overlap the pressure chamber in the first direction.

The positions of the first to third electrodes in the third direction can be arbitrarily changed as shown in FIGS. 9(a) to 9(c).

The ink separation layer 44 (see FIG. 5) may be omitted.

The present invention is not limited to printers, but can also be applied to facsimiles, copy machines, multifunction devices, and the like. Further, the present invention is also applicable to liquid ejecting devices used for purposes other than image recording (for example, liquid ejecting devices that eject conductive liquid onto a substrate to form a conductive pattern). Furthermore, the piezoelectric actuator according to the present invention can be applied to any device other than a liquid ejection device.

22; 222; 322; 422; 522 Piezoelectric actuator 40 Piezoelectric body 41-43 Piezoelectric layer 51 Drive electrode (first electrode)
51x One end 51y Other end 51t Thick part (first thick part)
51s Thin wall part (first thin wall part)
52 High potential electrode (second electrode)
52ax One end 52ay Other end 52t Thick part (second thick part)
52s Thin wall part (second thin wall part)
53 Low potential electrode (third electrode)
53ax One end 53ay Other end 53t Thick part (third thick part)
53s Thin wall part (3rd thin wall part)
60 Actuator part 61 First active part 62 Second active part 63 Third active part 100 Squeegee

Claims (13)

a piezoelectric body having a plurality of piezoelectric layers stacked in a first direction;
a first electrode;
a second electrode separated from the first electrode in the first direction;
A piezoelectric actuator comprising: a third electrode spaced apart from the first electrode in the first direction;
The piezoelectric body includes a first active portion sandwiched between the first electrode and the second electrode in the first direction, and a first active portion sandwiched between the first electrode and the third electrode in the first direction. a third active portion sandwiched between the first electrode and the third electrode in the first direction, and separated from the second active portion in a second direction perpendicular to the first direction; a third active part, the first active part having a portion disposed between the second active part and the third active part in the second direction,
the second active part is spaced apart from the first active part in one of the second directions;
The third active part is located in any of the following positions (a) to (c),
(a) A position in the first active part overlapping the other end in the second direction and the first direction; (b) A position in the first active part overlapping the other end in the second direction and the second direction. (c) an adjacent position separated from the first active part in the other direction in the second direction, and the distance between the third active part and the first active part in the second direction is the same as that of the second active part; The second electrode has a second thick part and a second thin part that is smaller in thickness in the first direction than the second thick part. has a section and a
In the second direction, the second electrode forms one end forming one end of the first active part in the second direction and the other end of the first active part in the second direction. and the other end having
The piezoelectric actuator, wherein the second thin portion is formed at the other end of the second electrode and not formed at the one end of the second electrode. The third electrode has a third thick part and a third thin part having a smaller thickness in the first direction than the third thick part,
In the second direction, the third electrode forms one end forming one end of the third active part in the second direction and the other end of the second active part in the second direction. and the other end having
The piezoelectric actuator according to claim 1, wherein the third thin portion is formed at the one end of the third electrode and not formed at the other end of the third electrode. a piezoelectric body having a plurality of piezoelectric layers stacked in a first direction;
a first electrode;
a second electrode separated from the first electrode in the first direction;
A piezoelectric actuator comprising: a third electrode spaced apart from the first electrode in the first direction;
The piezoelectric body includes a first active portion sandwiched between the first electrode and the second electrode in the first direction, and a first active portion sandwiched between the first electrode and the third electrode in the first direction. a third active portion sandwiched between the first electrode and the third electrode in the first direction, and separated from the second active portion in a second direction perpendicular to the first direction; a third active part, the first active part having a portion disposed between the second active part and the third active part in the second direction,
the second active part is spaced apart from the first active part in one of the second directions;
The third active part is located in any of the following positions (a) to (c),
(a) A position in the first active part overlapping the other end in the second direction and the first direction; (b) A position in the first active part overlapping the other end in the second direction and the second direction. (c) an adjacent position separated from the first active part in the other direction in the second direction, and the distance between the third active part and the first active part in the second direction is the same as that of the second active part; The third electrode has a third thick part and a third thin part that is smaller in thickness in the first direction than the third thick part. has a section and a
In the second direction, the third electrode forms one end forming one end of the third active part in the second direction and the other end of the second active part in the second direction. and the other end having
The piezoelectric actuator, wherein the third thin portion is formed at the one end of the third electrode and not formed at the other end of the third electrode. The second electrode has a second thick part and a second thin part having a smaller thickness in the first direction than the second thick part,
In the second direction, the second electrode forms one end forming one end of the first active part in the second direction and the other end of the first active part in the second direction. and the other end having
4. The piezoelectric actuator according to claim 3, wherein the second thin part is formed at the other end of the second electrode and not at the one end of the second electrode. The third active part is
(a) located at a position overlapping the other end in the second direction of the first active part in the first direction;
The second thick portion and the third thick portion do not overlap each other in the first direction and are adjacent to each other in the second direction,
The second thin part overlaps the third thick part in the first direction,
The piezoelectric actuator according to claim 2 or 4, wherein the third thin wall portion overlaps the second thick wall portion in the first direction. The third active part is
(a) located at a position overlapping the other end in the second direction of the first active part in the first direction;
the second thick portion and the third thick portion are spaced apart from each other in the second direction;
The second thin part and the third thin part overlap each other in the first direction between the second thick part and the third thick part in the second direction, The piezoelectric actuator according to claim 2 or 4. The first electrode has a first thick part and a first thin part having a smaller thickness in the first direction than the first thick part,
In the second direction, the first electrode forms one end forming one end of the second active part in the second direction and the other end of the third active part in the second direction. and the other end having
7. The method according to claim 1, wherein the first thin part is formed at the one end of the first electrode and not formed at the other end of the first electrode. piezoelectric actuator. Claims 1, 2, and 4, wherein the distance between the second active part and the first active part in the second direction is equal to or less than the length of the second thin part in the second direction. , 5, 6. The piezoelectric actuator according to any one of , 5 and 6. Claims 2, 3, and 4, wherein the distance between the second active part and the first active part in the second direction is equal to or less than the length of the third thin part in the second direction. , 5, 6. The piezoelectric actuator according to any one of , 5 and 6. a plurality of the first electrodes are arranged in the second direction,
Claims 1 and 2, characterized in that, for each of the plurality of first electrodes, the second thin part is disposed on the same side in the second direction as the second thick part. 9. The piezoelectric actuator according to any one of 4, 5, 6, and 8. a plurality of the first electrodes are arranged in the second direction,
Claims 2 and 3, characterized in that, for each of the plurality of first electrodes, the third thin wall portion is disposed on the same side in the second direction as the third thick wall portion. 10. The piezoelectric actuator according to any one of 4, 5, 6, and 9. a piezoelectric body having a plurality of piezoelectric layers stacked in a first direction; a first electrode; a second electrode spaced apart from the first electrode in the first direction; and a second electrode spaced apart from the first electrode in the first direction. A method for manufacturing a piezoelectric actuator comprising: a third electrode;
The piezoelectric body includes a first active portion sandwiched between the first electrode and the second electrode in the first direction, and a first active portion sandwiched between the first electrode and the third electrode in the first direction. a third active portion sandwiched between the first electrode and the third electrode in the first direction, and separated from the second active portion in a second direction perpendicular to the first direction; a third active part, the first active part having a portion disposed between the second active part and the third active part in the second direction,
the second active part is spaced apart from the first active part in one of the second directions;
The third active part is located in any of the following positions (a) to (c),
(a) A position in the first active part overlapping the other end in the second direction and the first direction; (b) A position in the first active part overlapping the other end in the second direction and the second direction. (c) an adjacent position separated from the first active part in the other direction in the second direction, and the distance between the third active part and the first active part in the second direction is the same as that of the second active part; A step of forming the second electrode by screen printing by moving a squeegee from one side to the other side in the second direction, the position being shorter than the distance from the first active part in the second direction. A method for manufacturing a piezoelectric actuator, characterized by: a piezoelectric body having a plurality of piezoelectric layers stacked in a first direction; a first electrode; a second electrode spaced apart from the first electrode in the first direction; and a second electrode spaced apart from the first electrode in the first direction. A method for manufacturing a piezoelectric actuator comprising: a third electrode;
The piezoelectric body includes a first active portion sandwiched between the first electrode and the second electrode in the first direction, and a first active portion sandwiched between the first electrode and the third electrode in the first direction. a third active portion sandwiched between the first electrode and the third electrode in the first direction, and separated from the second active portion in a second direction perpendicular to the first direction; a third active part, the first active part having a portion disposed between the second active part and the third active part in the second direction,
the second active part is spaced apart from the first active part in one of the second directions;
The third active part is located in any of the following positions (a) to (c),
(a) A position in the first active part overlapping the other end in the second direction and the first direction; (b) A position in the first active part overlapping the other end in the second direction and the second direction. (c) an adjacent position separated from the first active part in the other direction in the second direction, and the distance between the third active part and the first active part in the second direction is the same as that of the second active part; A step of forming the third electrode by screen printing by moving a squeegee from the other side to the one side in the second direction, the position being shorter than the distance from the first active part in the second direction. A method for manufacturing a piezoelectric actuator, characterized by:

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