JP6699744B2 - Piezoelectric generator - Google Patents

Description

  The present invention relates to a piezoelectric power generation device in which a piezoelectric element and a support are bonded together, and the piezoelectric element and the support are deformed by pressing to extract electric power.

  Heretofore, various piezoelectric power generation devices utilizing deformation of piezoelectric elements have been proposed.

  The following Patent Document 1 describes a piezoelectric power generation device in which a piezoelectric element is bonded to a support that is a vibration plate. In Patent Document 1, the support and the piezoelectric element are bonded together with an adhesive. The piezoelectric element also has first and second outer layer electrodes and an inner layer electrode. The first outer layer electrode is formed from one side surface to the main surface of the piezoelectric element body. The second outer layer electrode is formed from the other side surface of the piezoelectric element body to the main surface. The inner layer electrode is formed inside the piezoelectric element body. The inner layer electrode is connected to the side surface on the second outer layer electrode side, but is not connected to the side surface on the first outer layer electrode side. Therefore, a space is provided between the inner layer electrode and the side surface on the first outer layer electrode side.

JP, 2016-96252, A

  In the piezoelectric power generation device described in Patent Document 1, the piezoelectric element may be peeled from the support during driving to deform the piezoelectric element and the support by pressing to extract electric power. In addition, during driving, the piezoelectric element body and electrodes forming the piezoelectric element may be cracked or chipped, and the piezoelectric element may be damaged.

  An object of the present invention is to provide a piezoelectric power generation device in which peeling or breakage of a piezoelectric element does not easily occur during driving.

  A piezoelectric power generation device according to the present invention includes a support and a piezoelectric element bonded to the support, the piezoelectric element having first and second main surfaces facing each other, and the first and second main surfaces. A piezoelectric body that has a first side surface and a second side surface that are opposite to each other and that connect the main surfaces of the piezoelectric body and the first side surface that is provided inside the piezoelectric body and is drawn to the first side surface. The inner layer electrode is provided at the same height as the first inner layer electrode inside the piezoelectric body, is extended to the second side surface, and faces the outer peripheral edge of the first inner layer electrode. A first dummy electrode, a first outer layer electrode provided on the first main surface of the piezoelectric body, and a second main surface of the piezoelectric body. , And a second outer layer electrode.

  In one specific aspect of the piezoelectric power generation device according to the present invention, the piezoelectric body is a laminated piezoelectric body in which a plurality of piezoelectric body layers are laminated. In this case, much larger electric power can be taken out.

  In another specific aspect of the piezoelectric power generation device according to the present invention, the piezoelectric body is provided inside the piezoelectric body, is drawn out to the second side surface, and is arranged in the thickness direction of the piezoelectric body. The second inner layer electrode facing the first inner layer electrode is provided at the same height position as the second inner layer electrode inside the piezoelectric body, and is drawn to the first side surface. And a second dummy electrode facing the outer peripheral edge of the second inner layer electrode.

  In another specific aspect of the piezoelectric power generation device according to the present invention, the piezoelectric body has a plurality of the first and second inner layer electrodes and a plurality of the first and second dummy electrodes, The first and second inner layer electrodes are alternately arranged in the thickness direction of the piezoelectric body. In this case, much larger electric power can be taken out.

  In still another specific aspect of the piezoelectric power generation device according to the present invention, a plurality of facing regions in which the first inner layer electrode and the first dummy electrode face each other are arranged, and among the plurality of facing regions. At least two or more facing regions do not overlap in a plan view. In this case, the piezoelectric element is less likely to be damaged during manufacturing or driving.

  In still another specific aspect of the piezoelectric power generation device according to the present invention, the piezoelectric body further has third and fourth side surfaces that connect the first and second main surfaces and face each other. However, the first inner layer electrode and the first dummy electrode do not reach the third and fourth side surfaces, and the piezoelectric body is at least one of the third and fourth side surfaces. Further comprising a third inner layer electrode provided between the first inner layer electrode and the first dummy electrode, wherein the third inner layer electrode is the first inner layer electrode and the third inner layer electrode. It is electrically insulated from the first dummy electrode. In this case, much larger electric power can be taken out.

  In another broad aspect of the piezoelectric power generation device according to the present invention, a support and a piezoelectric element bonded to the support are provided, and the piezoelectric element has first and second main surfaces facing each other, and A piezoelectric body having first to fourth side surfaces connecting the first and second main surfaces, and at least one side surface of the first to fourth side surfaces provided inside the piezoelectric body. And is provided inside the piezoelectric body and the first inner layer electrode that is connected to one of the potentials, and is drawn to at least one of the first to fourth side surfaces. The second inner layer electrode, which is connected to the other potential, is provided at the same height position as the first inner layer electrode inside the piezoelectric body, and the first to fourth side surfaces are provided. A dummy electrode provided on at least one side surface of the first inner layer electrode, the dummy electrode being provided in a region around the first inner layer electrode, and a region that does not overlap with the second inner layer electrode in plan view, The dummy electrode is arranged.

  According to the present invention, it is possible to provide a piezoelectric power generation device in which the piezoelectric element is unlikely to peel or break during driving.

FIG. 1 is a schematic cross-sectional view showing a piezoelectric power generation device according to a first embodiment of the present invention. FIG. 2A and FIG. 2B are a perspective view of the support used in the first embodiment and a perspective view of the leg of the support taken out. FIG. 3 is a schematic plan view of a support used in the first embodiment of the present invention. FIG. 4 is a schematic plan view of a piezoelectric element used in the first embodiment of the present invention. FIG. 5 is a schematic perspective view showing a plane in which the first inner layer electrode is provided in the piezoelectric element used in the first embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of the piezoelectric power generation device according to the first embodiment of the present invention when no deformation occurs during manufacturing. FIG. 7 is a schematic perspective view showing a plane in which the first inner layer electrode is provided in the piezoelectric element used in the second embodiment of the present invention. FIG. 8 is a schematic perspective view showing a plane in which the first inner layer electrode is provided in the piezoelectric element used in the third embodiment of the present invention. FIG. 9 is a schematic cross-sectional view showing a piezoelectric power generation device according to the fourth embodiment of the present invention. FIG. 10 is a schematic cross-sectional view showing a piezoelectric power generation device according to the fifth embodiment of the present invention. FIG. 11 is a schematic cross-sectional view showing a piezoelectric power generation device according to the sixth embodiment of the present invention. FIG. 12 is a schematic perspective view showing a plane in which the first inner layer electrode is provided in the piezoelectric element used in the sixth embodiment of the present invention. FIG. 13 is a schematic perspective view showing a plane in which the second inner layer electrode is provided in the piezoelectric element used in the sixth embodiment of the present invention. FIG. 14 is a schematic cross-sectional view showing a piezoelectric power generation device of a comparative example.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings. In the drawings, the size and thickness of the piezoelectric power generation device may be exaggerated for convenience.

  It should be pointed out that each embodiment described in the present specification is an exemplification, and a partial replacement or combination of the configurations is possible between different embodiments.

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing a piezoelectric power generation device according to a first embodiment of the present invention. The piezoelectric power generation device 1 includes a support 2, an adhesive layer 3, and a piezoelectric element 4. Note that in FIG. 1, in order to make the laminated structure of the piezoelectric element 4 easy to see, the thickness of the piezoelectric element 4 is illustrated to be considerably thicker than the thickness of the plate-shaped portion 2 a of the support 2. Although not particularly limited, the thicknesses of the plate-shaped portion 2a and the piezoelectric element 4 are practically equal to each other.

  As shown in a perspective view of the support member in FIG. 2A, the support member 2 includes a plate-shaped portion 2a having a square planar shape and a plurality of leg portions 2b protruding downward from the lower surface of the plate-shaped portion 2a. Have. FIG. 2B is a perspective view schematically showing one leg 2b taken out. In the present embodiment, the leg 2b has a triangular prism shape. However, the shape of the leg portion may be another shape such as a cylinder or a square pole, or may be a shape such as a truncated cone or a truncated pyramid, and is not particularly limited. The planar shape of the plate-shaped portion 2a is not limited to a rectangle such as a square or a rectangle, but may be any shape such as a circle or a polygon having five or more sides.

  As will be described later, the plate-shaped portion 2a of the support 2 bends and deforms together with the piezoelectric element 4 during power generation. Therefore, it is desirable that the plate-shaped portion 2a of the support body 2 be made of an elastic plate such as a metal plate. As a material for such a metal plate, an appropriate metal or alloy such as stainless steel or SUS can be used.

  The leg portion 2b is formed integrally with the plate-shaped portion 2a, but the leg portion 2b which is a separate member may be joined to the plate-shaped portion 2a.

  FIG. 3 is a schematic plan view of the support 2. The plurality of legs 2b are provided at each corner of the plate-shaped portion 2a having a square planar shape, as indicated by the broken lines. Therefore, the plurality of legs 2b are arranged at equal intervals along the outer peripheral edge of the support 2 when the support 2 is viewed in plan. In the present invention, it is preferable that the plurality of legs be arranged at equal intervals along the outer peripheral edge of the support. As a result, the deformed plate-shaped portion 2a during power generation can be more reliably supported by the plurality of legs.

  Returning to FIG. 1, the piezoelectric element 4 is bonded to the upper surface 2a1 of the support 2 via the adhesive layer 3. As a material of the adhesive layer 3, an appropriate insulating adhesive such as an epoxy resin adhesive, an acrylic resin adhesive, or a silicone resin adhesive can be used. Moreover, even if an electrode connected to one potential of the piezoelectric element 4 is electrically connected to the support 2 by using a conductive adhesive as the adhesive layer 3 and forming the support 2 with a metal. Good.

  In the present embodiment, the piezoelectric element 4 has a laminated piezoelectric body 5 as a piezoelectric body. The laminated piezoelectric body 5 has the same planar shape as the support 2.

  The laminated piezoelectric body 5 has a plurality of piezoelectric layers. The thickness of the piezoelectric layer is not particularly limited, but may be, for example, 10 μm or more and 20 μm or less. The piezoelectric layers are alternately polarized in the thickness direction in opposite directions.

  The laminated piezoelectric body 5 has a substantially rectangular parallelepiped shape having first and second main surfaces 5a and 5b, first and second side surfaces 5c and 5d, and third and fourth side surfaces. However, the shape of the laminated piezoelectric body 5 is not particularly limited, and may be a disc shape or the like.

  The first and second main surfaces 5a and 5b face each other. The first and second side surfaces 5c and 5d connect the first and second main surfaces 5a and 5b. The first and second side faces 5c and 5d face each other. The third and fourth side surfaces also connect the first and second main surfaces 5a and 5b and face each other. Note that FIG. 1 does not show the third and fourth side surfaces.

  In the present embodiment, the piezoelectric element 4 is attached to the support body 2 with the adhesive layer 3 from the second main surface 5b side of the laminated piezoelectric body 5 as the piezoelectric body.

  In the present embodiment, the laminated piezoelectric body 5 is made of a material containing lead zirconate titanate-based ceramics as a main component. However, it may be made of a material containing other lead-free piezoelectric ceramics such as potassium sodium niobate or alkaline niobate ceramics as a main component.

  The laminated piezoelectric body 5 is manufactured, for example, as follows. First, prepare a plurality of green sheets. After that, the electrode paste is printed on a plurality of green sheets. After printing, a plurality of green sheets are laminated and pressure-bonded to produce a laminated body. Next, the produced laminated body is fired. Thereby, the laminated piezoelectric body 5 can be obtained.

  First and second outer surface electrodes 6 and 7 are provided on the first and second main surfaces 5a and 5b of the laminated piezoelectric body 5, respectively. A first electrode 8 connecting the first and second outer layer electrodes 6 and 7 is provided on the second side surface 5d. On the other hand, on the outer surface of the multilayer piezoelectric body 5, the second electrode 9 is provided so as to reach the second main surface 5b from the first main surface 5a through the first side surface 5c. The first and second electrodes 8 and 9 are connected to different potentials.

  FIG. 4 is a schematic plan view of a piezoelectric element used in the first embodiment of the present invention. Note that, in FIG. 4, the third and fourth side surfaces 5e and 5f, which are not illustrated in FIG. 1 as described above, are also illustrated.

  As shown in FIG. 4, the first outer layer electrode 6 has a rectangular shape. The first outer layer electrode 6 is drawn out to the second side face 5d and is electrically connected to the first electrode 8 of FIG. The second electrode 9 is provided so as to face the outer peripheral edge of the first outer layer electrode 6 with a gap. The second outer layer electrode 7 in FIG. 1 has the same shape as the first outer layer electrode 6.

  Returning to FIG. 1, a first inner layer electrode 10 is provided inside the laminated piezoelectric body 5. The first inner layer electrode 10 is drawn out to the first side face 5c and electrically connected to the second electrode 9.

  In addition, the first dummy electrode 11 is provided at the same height position as the first inner layer electrode 10 inside the multilayer piezoelectric body 5. The first dummy electrode 11 is drawn out to the second side surface 5d. In addition, the first dummy electrode 11 is arranged so as to face the outer peripheral edge of the first inner layer electrode 10 with a gap. The gap is the facing region 10a.

  In the present embodiment, the thickness of the first dummy electrode 11 is the same as that of the first inner layer electrode 10. However, in the present invention, the thickness of the first dummy electrode 11 does not have to be the same as that of the first inner layer electrode 10. The ratio of the electrode thickness of the first dummy electrode 11 to the first inner layer electrode 10 (first dummy electrode/first inner layer electrode) is, for example, within the range of 0.5 or more and 2.0 or less. You can Further, the length of the first dummy electrode 11 is shorter than that of the facing region 10a. However, in the present invention, the length of the first dummy electrode 11 may be longer than that of the facing region 10a as long as a short circuit does not occur.

  FIG. 5 is a schematic perspective view showing a plane in which the first inner layer electrode is provided in the piezoelectric element used in the first embodiment of the present invention. As shown in FIG. 5, the first inner layer electrode 10 and the first dummy electrode 11 have a rectangular shape. The first inner layer electrode 10 and the first dummy electrode 11 are provided so as to extend from the third side surface 5e to the fourth side surface 5f, respectively.

  Next, the power generation operation by the piezoelectric power generation device 1 will be described. At the time of power generation, in the piezoelectric power generation device 1, an external force is repeatedly applied from below the laminated piezoelectric body 5 toward above. When an external force is applied from below the piezoelectric element 4, the support 2 and the piezoelectric element 4 are bent and deformed so that the plate-shaped portion 2a of the support 2 and the piezoelectric element 4 project upward at their central portions. .. Along with this deformation, electric charges are generated in each piezoelectric layer of the piezoelectric element 4. Then, the electric power due to the generated charges is taken out from the terminals and the lead wires respectively connected to the first and second electrodes 8 and 9. In addition, at the time of power generation, in the piezoelectric power generation device 1, the power generation operation may be performed by repeatedly applying an external force from above the laminated piezoelectric body 5 to below.

  In the piezoelectric power generation device 1, since the first dummy electrode 11 is provided so as to reach the second side surface 5d, peeling or damage of the piezoelectric element 4 during driving is unlikely to occur. This can be explained with reference to FIGS. 1, 6 and 14.

  FIG. 14 is a schematic cross-sectional view showing a piezoelectric power generation device of a comparative example. As shown in FIG. 14, the piezoelectric generator 101 does not include the first dummy electrode. Therefore, in manufacturing the above-described laminated piezoelectric body 5, when a plurality of green sheets are laminated and pressure-bonded, the second side surface not provided with electrodes by the thickness of the first inner layer electrode 10 is formed. The vicinity of 5d is easily deformed. Therefore, as shown in FIG. 14, a gap (float) due to the deformation is generated in the vicinity of the second side surface 5d, and the piezoelectric element 4 is easily separated from the adhesive layer 3 as the piezoelectric element 4 is driven. As a result, the piezoelectric element 4 may be damaged. Moreover, since the vicinity of the second side face 5d is easily deformed, the first electrode 8 formed on the second side face 5d may be damaged. Therefore, in the piezoelectric generator 101 of the comparative example, the piezoelectric element 4 may be damaged during driving.

  On the other hand, in the piezoelectric power generation device 1 of the present embodiment, the first dummy electrode 11 is provided so as to reach the second side face 5d, so that a plurality of green sheets may be stacked during manufacturing. Excessive deformation is unlikely to occur in the vicinity of the second side surface 5d during crimping. However, since no electrode is provided in the region 10a where the first inner layer electrode 10 and the first dummy electrode 11 face each other, the deformation at the interface between the piezoelectric element 4 and the adhesive layer 3 as shown in FIG. There may be some floating due to. This is clear from comparison with the schematic cross-sectional view shown in FIG. 6 in the case where no deformation occurs during manufacturing. However, since the floating portion is supported by both ends as shown in FIG. 1, the applied stress is 1/16 that in the case of being supported by the cantilever as in the comparative example. Note that this can be explained as follows.

The amount of deformation of the laminated piezoelectric body 5 when there is a gap as in the comparative example is equal to the displacement δ in the cantilever beam, and the thickness of the first inner layer electrode 10 is set as the upper limit, and δ=( WL ³ )/(3EI). On the other hand, when the first dummy electrode 11 is provided as in the present embodiment, the deformation amount of the laminated piezoelectric body 5 is limited to the thickness of the first inner layer electrode 10, and the displacement δ at both ends (both ends) support. Equal to', and δ'=(WL ³ )/(48EI). As described above, since δ′ is 1/16 of δ, it can be seen that the deformation of the present embodiment is sufficiently suppressed.

  Therefore, in the piezoelectric power generation device 1, since the deformation in the vicinity of the second side surface 5d is suppressed, the piezoelectric element 4 is less likely to be peeled off. Further, since excessive deformation is unlikely to occur in the vicinity of the second side face 5d, the first electrode 8 formed on the second side face 5d is unlikely to be damaged. Therefore, in the piezoelectric power generation device 1, the piezoelectric element 4 is less likely to be peeled off or damaged during driving.

(Second embodiment)
FIG. 7 is a schematic perspective view showing a plane on which the first inner layer electrode is provided in the piezoelectric element used in the second embodiment of the present invention. As shown in FIG. 7, in the second embodiment, the first inner layer electrode 10 and the first dummy electrode 11 are not provided so as to extend from the third side surface 5e to the fourth side surface 5f, respectively. . In the piezoelectric generator of the second embodiment, the third inner layer electrodes 23, 24 are further provided between the third and fourth side faces 5e, 5f and the first inner layer electrode 10 and the first dummy electrode 11. It is provided. The third inner layer electrodes 23, 24 preferably have the same thickness as the first inner layer electrode 10, but may have different thicknesses.

  The third inner layer electrode 23 is led out to the second and third side faces 5d and 5e. The third inner layer electrode 24 is drawn out to the second and fourth side faces 5d and 5f. Further, the third inner layer electrodes 23, 24 are provided at the same height positions as the first inner layer electrode 10 and the first dummy electrode 11, and are electrically insulated. Other points are the same as those in the first embodiment.

  Also in the second embodiment, since the first dummy electrode 11 is provided so as to reach the second side surface 5d, peeling or damage of the piezoelectric element 4 during driving is unlikely to occur.

  In addition, in the piezoelectric power generation device of the second embodiment, the first inner layer electrode 10 and the first dummy electrode 11 are not drawn out to the third and fourth side faces 5e and 5f, respectively, and the electrode Since the area of is small, even more electric power can be taken out.

  Further, since the third inner layer electrodes 23, 24 are provided between the third and fourth side surfaces 5e, 5f and the first inner layer electrode 10 and the first dummy electrode 11, the first inner layer electrode 23, 24 is provided. Unintentional conduction with the first and second outer layer electrodes 6 and 7 connected to a potential different from that of the inner layer electrode 10 can be more reliably prevented. This point can be explained as follows.

  The first and second outer layer electrodes 6 and 7 are usually manufactured by sputtering or the like. Therefore, the first and second outer layer electrodes 6 and 7 formed on the first and second main surfaces 5a and 5b may wrap around to the third side surface 5e and the fourth side surface 5f. However, in the present embodiment, the third inner layer electrode 23 that is electrically insulated is provided between the third and fourth side surfaces 5e and 5f and the first inner layer electrode 10 and the first dummy electrode 11. , 24 are provided. Therefore, even if the first and second outer layer electrodes 6 and 7 wrap around to the third and fourth side surfaces 5e and 5f, they only conduct with the third inner layer electrodes 23 and 24, and the first inner layer Conduction with the electrode 10 is unlikely to occur. Therefore, in the piezoelectric power generation apparatus of the second embodiment, the generated electric charge leaks due to the first inner layer electrode 10 and the first and second outer layer electrodes 6 and 7 being electrically conducted and having the same potential. Can be suppressed more reliably.

(Third Embodiment)
FIG. 8 is a schematic perspective view showing a plane in which the first inner layer electrode is provided in the piezoelectric element used in the third embodiment of the present invention. As shown in FIG. 8, in the piezoelectric power generation device of the third embodiment, the third and fourth side surfaces 5e and 5f are provided with a third electrode between the first inner layer electrode 10 and the first dummy electrode 11. Dummy electrodes 25 and 26 are further provided. The third dummy electrodes 25, 26 preferably have the same thickness as the third inner layer electrodes 23, 24, but may have different thicknesses.

  The third dummy electrode 25 is drawn out to the first and third side faces 5c and 5e. The third dummy electrode 25 is provided at the same height as the third inner layer electrode 23, and faces the outer peripheral edge of the third inner layer electrode 23. Further, the third dummy electrode 26 is drawn out to the first and fourth side faces 5c, 5f. The third dummy electrode 26 is provided at the same height as the third inner layer electrode 24, and faces the outer peripheral edge of the third inner layer electrode 24. The other points are similar to those of the second embodiment.

  Also in the third embodiment, since the first dummy electrode 11 is provided so as to reach the second side face 5d, peeling or damage of the piezoelectric element 4 during driving is unlikely to occur.

  In addition, in the third embodiment, the third dummy electrodes 25, 26 are provided at the same height as the third inner layer electrodes 23, 24 so as to face the outer peripheral edges of the third inner layer electrodes 23, 24. Since the piezoelectric element 4 is provided, peeling and damage of the piezoelectric element 4 during driving are more difficult to occur.

(Fourth Embodiment)
FIG. 9 is a schematic cross-sectional view showing a piezoelectric power generation device according to the fourth embodiment of the present invention. As shown in FIG. 9, in the piezoelectric power generating device 21, a plurality of first inner layer electrodes 12 to 14 and a plurality of second inner layer electrodes 15 and 16 are provided inside the laminated piezoelectric body 5. There is. The first inner layer electrodes 12 to 14 and the second inner layer electrodes 15 and 16 face each other in the thickness direction of the laminated piezoelectric body 5, that is, in the laminating direction of the piezoelectric layers, and are alternately arranged. The first inner layer electrodes 12 to 14 are drawn out to the first side face 5c and are electrically connected to the second electrode 9. The second inner layer electrodes 15 and 16 are drawn out to the second side surface 5d and are electrically connected to the first electrode 8.

  Further, inside the multilayer piezoelectric body 5, a plurality of first dummy electrodes 17 to 19 are provided at the same height positions as the plurality of first inner layer electrodes 12 to 14, respectively. The first dummy electrodes 17 to 19 are drawn out to the second side surface 5d. The outer peripheral edges of the first dummy electrodes 17 to 19 are opposed to the first inner layer electrodes 12 to 14 with a gap therebetween.

  In this embodiment, the first dummy electrodes 17 to 19 have the same thickness as the first inner layer electrodes 12 to 14. However, in the present invention, the thickness of the first dummy electrodes 17 to 19 need not be the same as the thickness of the first inner layer electrodes 12 to 14. The ratio of the electrode thickness of the first dummy electrodes 17 to 19 to the first inner layer electrodes 12 to 14 (first dummy electrode/first inner layer electrode) is, for example, in the range of 0.5 or more and 2.0 or less. Can be within.

  Further, the plurality of second dummy electrodes 20 and 22 are provided at the same height positions as the plurality of second inner layer electrodes 15 and 16, respectively. The second dummy electrodes 20 and 22 are drawn out to the first side surface 5c. The outer peripheral edges of the second dummy electrodes 20 and 22 face the second inner layer electrodes 15 and 16, respectively, with a gap in between. The first dummy electrodes 17 to 19 and the second dummy electrodes 20 and 22 are alternately arranged in the thickness direction of the laminated piezoelectric body 5, that is, in the laminating direction of the piezoelectric layers.

  In the present embodiment, the second dummy electrodes 20 and 22 have the same thickness as the second inner layer electrodes 15 and 16. However, in the present invention, the thickness of the second dummy electrodes 20 and 22 may not be the same as the thickness of the second inner layer electrodes 15 and 16. The ratio of the electrode thickness of the second dummy electrodes 20 and 22 to the second inner layer electrodes 15 and 16 (second dummy electrode/second inner layer electrode) is, for example, in the range of 0.5 or more and 2.0 or less. Can be within.

  In addition, the first and second inner layer electrodes 12 to 16 have the same planar shape as the first inner layer electrode 10 of the piezoelectric power generation device 1. That is, the planar shapes of the first and second inner layer electrodes 12 to 16 are rectangular and are provided so as to extend from the third side surface 5e to the fourth side surface 5f shown in FIG.

  Similarly, the first dummy electrodes 17 to 19 and the second dummy electrodes 20 and 22 have the same planar shape as the first dummy electrode 11 of the piezoelectric power generation device 1. That is, the first dummy electrodes 17 to 19 and the second dummy electrodes 20 and 22 have a rectangular planar shape and are provided so as to extend from the third side surface 5e to the fourth side surface 5f shown in FIG. . Other points are the same as those in the first embodiment.

  Also in the piezoelectric power generation device 21, since the first dummy electrodes 17 to 19 and the second dummy electrodes 20 and 22 are provided so as to reach the first and second side faces 5c and 5d, the piezoelectric element at the time of driving No peeling or breakage of 4 is likely to occur.

(Fifth Embodiment)
In the fourth embodiment, the gaps between the first inner layer electrodes 12 to 14 and the first dummy electrodes 17 to 19, that is, the opposing regions are provided so as to overlap each other in a plan view. Further, the opposing regions of the second inner layer electrodes 15 and 16 and the second dummy electrodes 20 and 22 are provided so as to overlap each other in a plan view.

  On the other hand, in the fifth embodiment, as in the piezoelectric power generation device 31 shown in FIG. 10, the facing regions of the first inner layer electrodes 12 to 14 and the first dummy electrodes 17 to 19 are all viewed in a plan view. Do not overlap in. Further, the facing regions of the second inner layer electrodes 15 and 16 and the second dummy electrodes 20 and 22 do not overlap in a plan view. The other points are similar to those of the fourth embodiment.

  Also in the piezoelectric power generation device 31, since the first dummy electrodes 17 to 19 and the second dummy electrodes 20 and 22 are provided so as to be drawn to the first and second side faces 5c and 5d, the piezoelectric at the time of driving The element 4 is unlikely to come off or break. Further, in the piezoelectric power generation device 31, since the plurality of facing regions do not overlap each other in plan view and the thin portion is small, peeling or breakage of the piezoelectric element 4 during driving is further difficult to occur.

  As described above, in the present invention, at least two or more facing regions of the plurality of facing regions may not overlap in a plan view. In that case, peeling or damage of the piezoelectric element 4 during driving is more difficult to occur.

(Sixth Embodiment)
FIG. 11 is a schematic cross-sectional view showing a piezoelectric power generation device according to the sixth embodiment of the present invention. As shown in FIG. 11, the piezoelectric power generation device 41 includes a support 2 and an adhesive layer 3 similar to the piezoelectric power generation device 1, and a piezoelectric element 42. Further, the piezoelectric element 42 has the same laminated piezoelectric body 5 as the piezoelectric power generation device 1.

  In the piezoelectric element 42, first and second outer layer electrodes 43 and 44 are provided on the first and second main surfaces 5a and 5b of the laminated piezoelectric body 5, respectively. Inside the laminated piezoelectric body 5, a plurality of first inner layer electrodes 45 to 47 and a plurality of second inner layer electrodes 48, 49 are provided. The first inner layer electrodes 45 to 47 and the second inner layer electrodes 48, 49 are opposed to each other in the thickness direction of the laminated piezoelectric body 5, that is, in the laminating direction of the piezoelectric layers, and are arranged alternately.

  FIG. 12 is a schematic perspective view showing a plane in which the first inner layer electrode is provided in the piezoelectric element used in the sixth embodiment of the present invention. As shown in FIG. 12, the first inner layer electrode 45 has a substantially rectangular shape. The first inner layer electrode 45 is provided so as to reach the second and third side surfaces 5d and 5e. Further, the first inner layer electrode 45 is provided so as to reach a part of the first side surface 5c. The first inner layer electrode 45 does not reach the fourth side surface 5f.

  The connection electrode 50 electrically connected to the first inner layer electrode 45 is provided on the first side surface 5c. The connection electrode 50 is vertically extended on the first side surface 5c so as to extend from the first main surface 5a to the second main surface 5b in FIG.

  Further, the first dummy electrode 52 is provided in a region where the first inner layer electrode 45 is not provided. The first dummy electrode 52 is provided so as to reach the first side surface 5c. The first dummy electrode 52 is arranged at a position where it does not overlap the second inner layer electrodes 48, 49 in plan view. The first dummy electrode 52 is provided at the same height as the first inner layer electrode 45. Further, in the present embodiment, the thickness of the first dummy electrode 52 is the same as the thickness of the first inner layer electrode 45. However, in the present invention, the thickness of the first dummy electrode 52 does not have to be the same as the thickness of the first inner layer electrode 45.

  The first inner layer electrodes 46 and 47 have the same planar shape as the first inner layer electrode 45. Even on the same plane as the first inner layer electrodes 46 and 47, dummy electrodes having the same shape as the first dummy electrode 52 are provided at the same positions.

  FIG. 13 is a schematic perspective view showing a plane in which the second inner layer electrode is provided in the piezoelectric element used in the sixth embodiment of the present invention. As shown in FIG. 13, the second inner layer electrode 48 has a substantially rectangular shape. The second inner layer electrode 48 is provided so as to reach the second and fourth side surfaces 5d and 5f. The second inner layer electrode 48 is provided so as to reach a part of the first side surface 5c. The second inner layer electrode 48 does not reach the third side surface 5e.

  A connection electrode 51 electrically connected to the second inner layer electrode 48 is provided on the first side surface 5c. The connection electrode 51 is vertically extended on the first side surface 5c so as to extend from the first main surface 5a to the second main surface 5b of FIG.

  Returning to FIG. 13, the second dummy electrode 53 is provided in the area where the second inner layer electrode 48 is not provided. The second dummy electrode 53 is provided so as to reach the first side surface 5c. The second dummy electrode 53 is arranged at a position that does not overlap the first inner layer electrodes 45 to 47 in plan view. The second dummy electrode 53 is provided at the same height position as the second inner layer electrode 48. Further, in the present embodiment, the second dummy electrode 53 has the same thickness as the second inner layer electrode 48. However, in the present invention, the thickness of the second dummy electrode 53 need not be the same as the thickness of the second inner layer electrode 48.

  The first and second outer layer electrodes 43, 44 and the second inner layer electrode 49 have the same planar shape as the second inner layer electrode 48. Even on the same plane as the second inner layer electrode 49, the dummy electrode having the same shape as the second dummy electrode 53 is provided at the same position.

  Further, as shown in FIGS. 12 and 13, the connection electrode 50 is provided laterally separated from the connection electrode 51 on the first side surface 5c. The connection electrode 50 and the connection electrode 51 are connected to different potentials.

  In the piezoelectric power generation device 41, the first and second dummy electrodes such as the first and second dummy electrodes 52 and 53 are provided in a region which does not overlap with the first and second inner layer electrodes 45 to 49 in plan view. Has been. Therefore, there are few thin portions, and it is difficult for extra deformation to occur during manufacturing. Therefore, the above-mentioned floating is unlikely to occur. Therefore, even in the piezoelectric power generation device 41, peeling of the piezoelectric element 42 is unlikely to occur. Moreover, since there are few places where extra deformation occurs, the piezoelectric element 42 is less likely to be damaged. Therefore, even when the first and second dummy electrodes are arranged as in the piezoelectric power generation device 41, the effects of the present invention can be obtained.

1, 2, 31, 31, 41... Piezoelectric generator 2... Support 2a... Plate-shaped portion 2a1... Upper surface 2b... Leg portion 3... Adhesive layer 4, 42... Piezoelectric element 5... Multilayer piezoelectric body 5a, 5b... First , 2nd main surface 5c-5f... 1st-4th side surface 6, 43... 1st outer layer electrode 7,44... 2nd outer layer electrode 8, 9... 1st, 2nd electrode 10, 12- 14, 45 to 47... First inner layer electrode 10a... Opposing region 11... First dummy electrodes 15, 16, 48, 49... Second inner layer electrodes 17 to 19, 52... First dummy electrodes 20, 22, 53... Second dummy electrodes 23, 24... Third inner layer electrodes 25, 26... Third dummy electrodes 50, 51... Connection electrodes

Claims (6)

A support,
A piezoelectric element bonded to the support,
The piezoelectric element is
A first and a second main surface facing each other, and a piezoelectric body connecting the first and the second main surface and having first and second side surfaces facing each other,
A first inner layer electrode provided inside the piezoelectric body and extended to the first side surface;
The piezoelectric element is provided inside the piezoelectric body at the same height as the first inner layer electrode, is extended to the second side surface, and is opposed to the outer peripheral edge of the first inner layer electrode. 1 dummy electrode,
A first outer layer electrode provided on the first main surface of the piezoelectric body;
A second outer layer electrode provided on the second main surface of the piezoelectric body;
Have a,
A second inner layer, wherein the piezoelectric body is provided inside the piezoelectric body, is drawn out to the second side surface, and is opposed to the first inner layer electrode in the thickness direction of the piezoelectric body. electrode
Further has
The piezoelectric body has a plurality of the first and second inner layer electrodes and a plurality of the first dummy electrodes,
The first and second inner layer electrodes are alternately arranged in the thickness direction of the piezoelectric body,
A plurality of facing regions where the first inner layer electrode and the first dummy electrode face each other are arranged, and at least two or more facing regions of the plurality of facing regions do not overlap in plan view , Piezoelectric generator.   The piezoelectric power generation device according to claim 1, wherein the piezoelectric body is a laminated piezoelectric body in which a plurality of piezoelectric body layers are laminated. The piezoelectric body,
Provided inside of the front Symbol piezoelectric at the same height position as the second inner layer electrodes, the first is led to the side surface, and an outer peripheral edge and opposite the second inner electrode, further comprising a second dummy electrodes, the piezoelectric power generator according to claim 1 or 2. The piezoelectric body, it has a pre-Symbol second dummy electrodes of the multiple piezoelectric power generator according to claim 3. The piezoelectric body further has third and fourth side surfaces that connect the first and second main surfaces and face each other,
The first inner layer electrode and the first dummy electrode do not reach the third and fourth side surfaces,
The piezoelectric body further has a third inner layer electrode provided between at least one of the third and fourth side surfaces and the first inner layer electrode and the first dummy electrode. Then
Wherein the third inner electrode, said first inner electrode and the first dummy electrode and electrically insulated, the piezoelectric power generator according to any one of claims 1-4. A support,
A piezoelectric element bonded to the support,
The piezoelectric element is
A piezoelectric body having first and second main surfaces facing each other and first to fourth side surfaces connecting the first and second main surfaces;
A first inner layer electrode, which is provided inside the piezoelectric body, is drawn to at least one side surface of the first to fourth side surfaces, and is connected to one potential,
A second inner layer electrode that is provided inside the piezoelectric body, is drawn to at least one side surface of the first to fourth side surfaces, and is connected to the other potential,
It is provided at the same height position as the first inner layer electrode inside the piezoelectric body, and is drawn out to at least one side face of the first to fourth side faces, and A dummy electrode that is provided in a peripheral region and faces the outer peripheral edge of the first inner layer electrode ,
In a plan view, the dummy electrode is arranged in a region that does not overlap with the second inner layer electrode ,
The first inner layer electrode and the second inner layer electrode face each other in the thickness direction of the piezoelectric body,
The piezoelectric body has a plurality of the first and second inner layer electrodes and a plurality of the dummy electrodes,
The first and second inner layer electrodes are alternately arranged in the thickness direction of the piezoelectric body,
A plurality of facing regions in which the first inner layer electrode and the dummy electrode face each other are arranged, and at least two or more facing regions of the plurality of facing regions do not overlap in a plan view. ..

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