Piezoelectric elements, piezoelectric ultrasonic motors, optical component drive devices, camera devices, and electronic devices

Abstract

To provide a piezoelectric element that is less likely to cause short circuit and disconnection between electrode layers even when a thickness of one piezoelectric layer becomes thin and that has a stable operation, and to provide a piezoelectric ultrasonic motor, an optical member drive device, a camera device, and electronic equipment.SOLUTION: A piezoelectric element 73a comprises: a plurality of piezoelectric layers 73y; electrode layers; and through hole electrodes electrically connecting between two electrode layers. The electrode layers have: first and second electrode layers 73e and 73f formed on a top surface 73s and even-numbered boundary surfaces 73u; and common electrode layers 73h formed on odd-numbered boundary surfaces 73u and a lower surface 73t. The through hole electrodes have: first and second through hole electrodes TH1 and TH2; and third through hole electrodes TH3 that connect between the common electrode layers 73h. The second electrode layers 73f are arranged so as to be separated toward an opposite side to the first electrode layers 73e while interposing separated parts 73j. The third through hole electrodes TH3 are arranged at positions of the separated parts 73j.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a piezoelectric element, a piezoelectric ultrasonic motor using the piezoelectric element, an optical member driving device using the piezoelectric ultrasonic motor, a camera device, and an electronic apparatus.

Background Art

[0002] With the development of the information technology industry, demand for ultra-compact camera modules to be mounted on smartphones and the like is increasing. In a camera module, a voice coil motor or a piezoelectric ultrasonic motor can be used as a driving mechanism for an optical member such as a lens body. This piezoelectric ultrasonic motor has advantages of fast response speed, a reverse drive prevention function, and high transfer resolution. For this reason, piezoelectric ultrasonic motors are expected as drive units for optical members such as ultra-compact camera modules.

[0003] The piezoelectric ultrasonic motor described in Patent Document 1 includes a rotor, an elastic body, and a piezoelectric element. The piezoelectric element includes a first stacked internal piezoelectric body having a first external electrode and a first internal electrode, a second stacked internal piezoelectric body having a second external electrode and a second internal electrode, and an internal ground electrode and an external ground electrode. In this piezoelectric ultrasonic motor, when an alternating voltage is applied between the first internal electrode and the internal ground electrode, and between the second internal electrode and the internal ground electrode, the piezoelectric element and the elastic body are deformed to rotationally drive the rotor. According to this piezoelectric ultrasonic motor, by thinning the piezoelectric layer between the electrodes, the voltage applied between the respective electrodes to obtain a required driving force can be lowered.

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] Incidentally, the piezoelectric ultrasonic motor disclosed in Patent Document 1 employs a power supply method in which an AC voltage is applied from each external electrode provided on the outer surface of the piezoelectric element to each internal electrode. However, this power supply method has the problem that as the thickness of one piezoelectric layer decreases, short circuits and open circuits between electrode layers are more likely to occur, which can lead to unstable operation.

[0006] This invention has been made in view of the above problems, and aims to provide a piezoelectric element that is less prone to short circuits and disconnections between electrode layers even when the thickness of a single piezoelectric layer is reduced, and that operates stably, a piezoelectric ultrasonic motor using this piezoelectric element, an optical component driving device utilizing the piezoelectric ultrasonic motor, a camera device, and electronic equipment. [Means for solving the problem]

[0007] To solve the above problems, a piezoelectric element in a preferred embodiment of the present invention comprises a plurality of stacked piezoelectric layers, electrode layers disposed on the upper surface, lower surface, and each interface between the piezoelectric layers, and through-hole electrodes electrically connecting two of the electrode layers provided on different surfaces, wherein the electrode layers have a first electrode layer and a second electrode layer formed on the upper surface and even-numbered interface surfaces from the upper surface side, and a common electrode layer formed on odd-numbered interface surfaces from the upper surface side and the lower surface, and the through-hole electrodes connect the first electrode layers The electrode comprises a through-hole electrode, a second through-hole electrode connecting the second electrode layer, and a third through-hole electrode connecting the common electrode layer. On each surface, the first electrode layer is arranged on one side in a predetermined direction, the second electrode layer is arranged at a distance from the first electrode layer, separated by a separation portion, on the other side opposite to the first electrode layer, the common electrode layer is arranged on substantially the entire surface except for the positions of the first through-hole electrode, the second through-hole electrode and their surroundings, and the third through-hole electrode is arranged at the position of the separation portion.

[0008] In this embodiment, the third through-hole electrode may be located in the center of the entire element when viewed from the stacking direction.

[0009] Furthermore, the first through-hole electrode and the second through-hole electrode may be positioned symmetrically with respect to the central part of the entire element when viewed from the stacking direction.

[0010] Furthermore, the first through-hole electrode and the second through-hole electrode may be provided at the ends of the entire element when viewed from the stacking direction.

[0011] Furthermore, the number of piezoelectric layers may be odd.

[0012] Another preferred embodiment of the present invention is a piezoelectric ultrasonic motor comprising a drive shaft, a columnar body having a through hole through which the drive shaft is inserted, and the piezoelectric element provided on the side surface of the columnar body for driving the drive shaft via the columnar body, wherein the predetermined direction is parallel to the axial direction of the drive shaft.

[0013] In this embodiment, the columnar body is a rectangular parallelepiped, the drive shaft is inserted through the through hole that penetrates between the two bottom surfaces of the rectangular parallelepiped, and the piezoelectric element may be provided on each of the four side surfaces of the rectangular parallelepiped.

[0014] Furthermore, the common electrode layer of each piezoelectric element may be electrically connected to the columnar body, and the first electrode layer of each piezoelectric element may be subjected to a voltage of the same frequency, the same phase, and the same height, while the second electrode layer may be subjected to a voltage of the same frequency, a phase difference of 90 degrees, and the same height as the voltage applied to the first electrode layer.

[0015] Another preferred embodiment of the present invention is an optical member driving device comprising a carrier for supporting an optical member and the piezoelectric ultrasonic motor for driving the carrier.

[0016] Another preferred embodiment of the present invention is a camera device characterized by comprising the above-described optical element driving device.

[0017] Another preferred embodiment of the present invention is an electronic device that includes the above-described camera device. [Effects of the Invention]

[0018] The piezoelectric element according to the present invention comprises a plurality of stacked piezoelectric layers, electrode layers disposed on the upper surface, lower surface, and each interface between the piezoelectric layers, and through-hole electrodes that electrically connect two of the electrode layers provided on different surfaces. The electrode layers include a first electrode layer and a second electrode layer formed on the upper surface and even-numbered interface surfaces from the upper surface side, and a common electrode layer formed on odd-numbered interface surfaces from the upper surface side and the lower surface. The through-hole electrodes include a first through-hole electrode connecting the first electrode layers, a second through-hole electrode connecting the second electrode layers, and a third through-hole electrode connecting the common electrode layer. On each surface, the first electrode layer is disposed on one side in a predetermined direction, the second electrode layer is disposed on the other side opposite to the first electrode layer with a separation portion in between, the common electrode layer is disposed on substantially the entire surface except for the positions of the first and second through-hole electrodes and their surroundings, and the third through-hole electrode is disposed at the position of the separation portion. Therefore, each electrode layer is electrically connected by individual through-hole electrodes, making it difficult for short circuits or disconnections to occur between electrode layers even if the thickness of a single piezoelectric layer is reduced. Consequently, it is possible to provide a piezoelectric element with stable operation, a piezoelectric ultrasonic motor using this piezoelectric element, an optical component drive device, a camera device, and electronic equipment utilizing this piezoelectric ultrasonic motor. [Brief explanation of the drawing]

[0019] [Figure 1] This is a front view of a smartphone 9 equipped with a camera device 8 that includes an optical element drive device 5 utilizing a piezoelectric ultrasonic motor 100, which is one embodiment of the present invention. [Figure 2] This is a perspective view of the optical component drive device 5. [Figure 3] This is a perspective view of the optical component drive device 5 with case 10 removed. [Figure 4] This is a side view of the carrier 20 and base 30 of the optical component drive device 5. [Figure 5]It is a perspective view of the piezoelectric ultrasonic motor 100 of the optical member driving device 5. [Figure 6] It is a perspective view of the piezoelectric ultrasonic motor 100 of FIG. 5 with the felt 75 and the FPC 72 removed. [Figure 7] It is a perspective view of the piezoelectric element 73a of FIG. 6. [Figure 8] It is a cross-sectional view of the piezoelectric element 73a of FIG. 7 taken along line Ia-Ib. [Figure 9A] This is one example of the piezoelectric element 73a, and is a top view of even-numbered boundary surfaces 73u viewed from the upper surface side. [Figure 9B] It is a top view of odd-numbered boundary surfaces 73u viewed from the upper surface side in the piezoelectric element 73a of FIG. 9A. MODE FOR CARRYING OUT THE INVENTION

[0020] As shown in FIG. 1, a camera device 8 including an optical member driving device 5 using a piezoelectric ultrasonic motor 100 (hereinafter sometimes simply referred to as motor 100) according to an embodiment of the present invention is housed in a housing of a smartphone 9.

[0021] The camera device 8 includes a lens body 6, an image sensor 7, and the optical member driving device 5 that drives the lens body 6 as an optical member. The image sensor 7 converts light incident through the lens body 6 into an image signal and outputs the image signal. The optical member driving device 5 drives the lens body 6 along a direction parallel to the optical axis of the lens body 6.

[0022] Hereinafter, the configuration of the optical member driving device 5 will be described assuming an XYZ orthogonal coordinate system including a Z axis parallel to the optical axis of the lens body 6, and an X axis and a Y axis which are orthogonal to each other and orthogonal to the Z axis. Further, hereinafter, when viewed from the lens body 6, the subject side may be referred to as the +Z side, and the opposite side (the image sensor 7 side) may be referred to as the -Z side.

[0023] As shown in FIG. 2, the optical member driving device 5 houses a carrier 20 having a hole 20a for supporting the lens body 6 in a rectangular parallelepiped case 10. Light from a subject passes through the center of the optical member driving device 5.

[0024] As shown in Figure 3, the carrier 20 is positioned on the base 30. The base 30 is a metal plate-like member with a bottom portion 31 that extends in the XY direction, and a side portion 32 that is bent at a right angle to the +Z side at the +Y end of the bottom portion 31. The carrier 20 is positioned on the +Z side of the bottom portion 31. The carrier 20 has a shape that integrates an annular portion 20b formed around a hole 20a for housing the lens body 6, and a substantially rectangular parallelepiped-shaped connecting portion 20c provided on the +Y side facing the side portion 32.

[0025] Near the side surface 32 of the bottom surface 31 of the base 30, a main guide shaft 61 and a sub-guide shaft 62 are positioned spaced apart in the X direction, their base ends fixed and erected facing the +Z direction. The main guide shaft 61 and the sub-guide shaft 62 are housed in a hole 21 and a notch 22, respectively, formed in the connecting portion 20c of the carrier 20, spaced apart in the X direction, and guide the carrier 20 to move in the Z direction. A notch 23 is also formed on the +Y side end face of the carrier 20 at a position corresponding to the +X side of the hole 21, and a motor 100 is housed in this notch 23. As will be described later, the drive shaft 71 of the motor 100 has its base end 71b fixed to the bottom surface 31 and erected facing the +Z direction. The optical element driving device 5 drives the carrier 20 in the Z direction using the motor 100 according to this embodiment as a driving source.

[0026] A yoke 51 and a Hall IC 52 are positioned on the -Y side of the side portion 32 of the base 30. A magnet 53 is positioned on the surface opposite the side portion 32, corresponding to the position between the hole 21 and the notch 22 on the carrier 20. The Hall IC 52 detects the position of the carrier 20 in the Z direction by detecting the magnetic field of the magnet 53. The yoke 51 and the magnet 53 attract each other, and the carrier 20 is pulled towards the side portion 32. As a result, the inner walls of the hole 21 and the notch 22 of the carrier 20 are pressed against the main guide shaft 61 and the sub-guide shaft 62 with appropriate pressure in the +Y direction, stabilizing the attitude of the carrier 20 and its drive in the Z direction.

[0027] As shown in Figure 4, the motor 100 housed in the carrier 20 has a drive shaft 71 extending in the Z direction. The base end 71b on the -Z side of the drive shaft 71 has a smaller diameter than the main body portion 71a of the drive shaft. This smaller diameter portion, the base end 71b, is inserted into a hole formed in the bottom surface portion 31 and fixed by a method such as crimping or welding. The main guide shaft 61 and the sub-guide shaft 62 have a similar structure and are fixed in the same manner. In addition, in the motor 100, the lead-out portion 72a of the FPC (Flexible Printed Circuits) 72 is pulled out in a direction parallel to the drive shaft 71, curved 180 degrees, and positioned on the -Y side surface of the side portion 32. The FPC 72 is further electrically connected to the outside of the device.

[0028] As shown in Figures 5 and 6, the motor 100 has a metal columnar body 74. In this embodiment, the columnar body 74 is a rectangular prism having two opposing bottom surfaces 74e and 74f and side surfaces 74a, 74b, 74c and 74d surrounding the area between the two bottom surfaces 74e and 74f. The columnar body 74 also has a through hole 74g that penetrates between the two bottom surfaces 74e and 74f. The drive shaft 71 is inserted through the through hole 74g of the columnar body 74.

[0029] The FPC72 is equipped with multiple (four in the example in Figure 5) sheet-shaped piezoelectric elements 73a, 73b, 73c, and 73d. The FPC72 is wound around the columnar body 74 from the outside, with the multiple piezoelectric elements 73a, 73b, 73c, and 73d in contact with the side portions 74a, 74b, 74c, and 74d of the columnar body 74. A first electrode layer 73e is formed on the +Z side of the upper surface 73s of each piezoelectric element 73a, 73b, 73c, and 73d on the FPC72 side, and a second electrode layer 73f is formed on the -Z side, separated from the first electrode layer 73e. The first electrode layer 73e and the second electrode layer 73f are electrically connected to the FPC72. Electrode layers are also formed on the lower surface 73t of each piezoelectric element 73a, 73b, 73c, and 73d, opposite to the upper surface 73s, and are electrically connected to the columnar body 74. The FPC 72 also has a common terminal portion 72b, which is electrically connected to the bottom surface portion 74e of the columnar body 74. The FPC 72 supplies driving power to the multiple piezoelectric elements 73a, 73b, 73c, and 73d.

[0030] Furthermore, the FPC 72 is wound around the columnar body 74 in the order of the pull-out portion 72a to the side portions 74c, 74b, 74a, and 74d. The FPC 72 has R portions 72R at each position opposite to the corners between the four side portions 74a, 74b, 74c, and 74d, excluding the corner between side portion 74c and side portion 74d. The width of the R portion 72R in the Z direction is approximately the same as the width of the adjacent portion. In addition, the outer surface of the FPC 72 wound around the columnar body 74 is covered with felt 75, which is a cushioning material. The motor 100, covered with felt 75, is fixed to the inner walls on the -X side, -Y side, and +X side within the notch portion 23 of the carrier 20.

[0031] Each of the piezoelectric elements 73a, 73b, 73c, and 73d has the same structure. Hereafter, piezoelectric element 73a will be described, and the description of piezoelectric elements 73b, 73c, and 73d will be based on the description of piezoelectric element 73a.

[0032] As shown in Figure 7, the piezoelectric element 73a is a rectangular plate parallel to the ZX direction. Figure 8 is a cross-sectional view of the piezoelectric element 73a along the line Ia-Ib in Figure 7, that is, a cross-sectional view obtained by cutting the piezoelectric element 73a with a plane parallel to the Y direction, passing through the diagonal line that passes through the +ZX side corner and the -Z+X side corner of the piezoelectric element 73a.

[0033] As shown in Figures 7 and 8, the piezoelectric element 73a has multiple piezoelectric layers 73y stacked in the thickness direction of its plate. The piezoelectric layers 73y are usually an odd number of layers, and in the example shown in Figures 7 and 8, there are five layers for illustrative purposes only. Electrode layers are arranged on the upper surface 73s, the lower surface 73t, and each interface surface 73u between the piezoelectric layers 73y of the piezoelectric element 73a. The electrode layers on each surface are electrically connected by through-hole electrodes that penetrate the piezoelectric layers 73y vertically. The through-hole electrodes are provided so as to penetrate a conductor vertically inside a through-hole provided at a predetermined position in the piezoelectric layer 73y, and electrically connect the electrode layers provided above and below the piezoelectric layer 73y. In Figure 7, each through-hole electrode shows only the electrical connection point in each electrode layer.

[0034] Specifically, the electrode layer comprises a first electrode layer 73e, a second electrode layer 73f, and a common electrode layer 73h. The first electrode layer 73e and the second electrode layer 73f are provided on the upper surface 73s and the even-numbered (in this embodiment, the 2nd and 4th) interface surfaces 73u counting from the upper surface 73s side. On each surface, the first electrode layer 73e is positioned on the +Z side, and the second electrode layer 73f is positioned separated from the first electrode layer 73e on the -Z side, separated by a separation portion 73j. The common electrode layer 73h is provided on the odd-numbered (in this embodiment, the 1st and 3rd) interface surfaces 73u counting from the upper surface 73s side and on the lower surface 73t. The common electrode layer 73h is provided on almost the entire surface, with some exceptions. Therefore, when viewed in the thickness direction of the piezoelectric element 73a, the central part in the Z direction is alternately provided with a separation portion 73j without an electrode layer and a common electrode layer 73h. On the +Z side, the first electrode layer 73e and the common electrode layer 73h are provided opposite each other with the piezoelectric layer 73y in between. On the -Z side, the second electrode layer 73f and the common electrode layer 73h are provided opposite each other with the piezoelectric layer 73y in between.

[0035] The first electrode layer 73e on each surface is electrically connected by a first through-hole electrode TH1, the second electrode layer 73f on each surface is electrically connected by a second through-hole electrode TH2, and the common electrode layer 73h on each surface is electrically connected by a third through-hole electrode TH3. On the interface surface 73u where the common electrode layer 73h is located, notches 73k are provided in the common electrode layer 73h at the positions of the first through-hole electrode TH1 and its surroundings, and at the positions of the second through-hole electrode TH2 and its surroundings. As a result, the first through-hole electrode TH1 and the second through-hole electrode TH2 do not come into contact with the common electrode layer 73h. Furthermore, on the interface surface 73u where the first electrode layer 73e and the second electrode layer 73f are located, a third through-hole electrode TH3 is provided at the position of a separation portion 73j. As a result, the third through-hole electrode TH3 does not come into contact with the first electrode layer 73e and the second electrode layer 73f.

[0036] In the illustrated example, the first through-hole electrode TH1 and the second through-hole electrode TH2 are located at the +ZX side corner and the -Z+X side corner of the piezoelectric element 73a, while the third through-hole electrode TH3 is located at the center of the piezoelectric element 73a in both the Z and X directions, i.e., at the center of the piezoelectric element 73a when viewed from the stacking direction. Thus, the first through-hole electrode TH1 and the second through-hole electrode TH2 are positioned point-symmetrically with respect to the center of the entire piezoelectric element 73a when viewed from the stacking direction. Furthermore, the first through-hole electrode TH1 and the second through-hole electrode TH2 are located at the ends of the entire piezoelectric element 73a when viewed from the stacking direction. By arranging the first through-hole electrode TH1, the second through-hole electrode TH2, and the third through-hole electrode TH3 in this manner, the influence of the through-hole electrodes on the expansion and contraction and deformation of the piezoelectric element 73a can be minimized. Each electrode layer is electrically connected to the others by individual through-hole electrodes, making it difficult for short circuits or disconnections to occur between electrode layers even if the thickness of a single piezoelectric layer 73y is reduced. Therefore, a piezoelectric element 73a with stable operation can be obtained.

[0037] A common electrode layer 73h is located on the lower surface 73t of the piezoelectric element 73a. This common electrode layer 73h is electrically connected to a common terminal portion 72b via a columnar body 74. This common terminal portion 72b is electrically connected to the FPC 72. A first electrode layer 73e and a second electrode layer 73f are located on the upper surface 73s, and these first electrode layer 73e and second electrode layer 73f are electrically connected to the FPC 72.

[0038] The other piezoelectric elements 73b, 73c, and 73d have a similar configuration to piezoelectric element 73a, and include a piezoelectric layer 73y, a first electrode layer 73e, a second electrode layer 73f, a common electrode layer 73h, a first through-hole electrode TH1, a second through-hole electrode TH2, and a third through-hole electrode TH3. The FPC 72 supplies driving power to the multiple piezoelectric elements 73a, 73b, 73c, and 73d.

[0039] In the above configuration, the first electrode layers 73e of each piezoelectric element 73a, 73b, 73c, and 73d are each subjected to a voltage of the same frequency, the same phase, and the same height, and the same frequency, a voltage difference of 90 degrees, and the same height as the voltage applied to the first electrode layer 73e are applied to each second electrode layer 73f. The common electrode layer 73h is grounded. As a result, the piezoelectric elements 73a, 73b, 73c, and 73d at positions corresponding to the first electrode layer 73e and the second electrode layer 73f respectively expand and contract in the direction of their plate surface. The columnar body 74 does not undergo such expansion and contraction, so the portion of the columnar body 74 from the piezoelectric elements 73a, 73b, 73c, and 73d corresponding to the first electrode layer 73e and the second electrode layer 73f to the through hole 74g undergoes deformation that repeatedly alternates between a bowl shape and its inverted form. That is, the inner wall surfaces of the corresponding through holes 74g undergo deformation that repeatedly alternates between a bowl shape and its inverted form. In this way, the piezoelectric elements 73a, 73b, 73c, and 73d and the columnar body 74 constitute a vibrating body.

[0040] Since the voltage applied to the first electrode layer 73e and the voltage applied to the second electrode layer 73f have a phase difference of 90 degrees, the deformation of the inner wall surface of the through hole 74g at the position corresponding to the first electrode layer 73e and the deformation of the inner wall surface of the through hole 74g at the position corresponding to the second electrode layer 73f also have a phase difference of 90 degrees. As a result, the inner wall surface of the through hole 74g moves in an elliptical motion along the axial direction of the through hole 74g, and the columnar body 74 moves in the +Z direction or the -Z direction along the drive shaft 71. The direction of movement of this columnar body 74 can be controlled by changing the phase difference of the applied voltage.

[0041] In this embodiment, the carrier 20 is fixed to the columnar body 74 as described above. Therefore, according to this embodiment, the carrier 20 can be moved in the Z direction by supplying driving power from the FPC 72 to the piezoelectric elements 73a, 73b, 73c, and 73d.

[0042] In this embodiment, the piezoelectric elements 73a, 73b, 73c, and 73d are composed of multiple stacked piezoelectric layers 73y, a first electrode layer 73e and a second electrode layer 73f arranged on the upper surface 73s, the lower surface 73t, and the interface surface 73u between the piezoelectric layers 73y, and a common electrode layer 73h. In each piezoelectric layer 73y, the first electrode layer 73e or the second electrode layer 73f faces the common electrode layer 73h, and a voltage is applied. Therefore, if the overall thickness of the piezoelectric elements is the same, the thickness of each piezoelectric layer 73y is thinner when stacked compared to a configuration without stacked piezoelectric layers 73y, and the same amount of expansion and contraction can be obtained even with a lower applied voltage. Accordingly, the voltage applied between the first electrode layer 73e and the second electrode layer 73f and the common electrode layer 73h can be lowered in order to obtain the required driving force.

[0043] Furthermore, in the piezoelectric elements 73a, 73b, 73c, and 73d of this embodiment, the first electrode layers 73e on each surface are electrically connected to each other by a first through-hole electrode TH1 that penetrates the piezoelectric layer 73y. The second electrode layers 73f on each surface are electrically connected to each other by a second through-hole electrode TH2 that penetrates the piezoelectric layer 73y. At the interface surface 73u where the common electrode layer 73h is located, the common electrode layer 73h is not located at the position of the first through-hole electrode TH1 and its surroundings, nor at the position of the second through-hole electrode TH2 and its surroundings, and a notch 73k is provided. The common electrode layer 73h is not in contact with the first through-hole electrode TH1 and the second through-hole electrode TH2. In addition, the common electrode layers 73h on each surface are electrically connected to each other by a third through-hole electrode TH3 that penetrates the piezoelectric layer 73y. At the interface 73u where the first electrode layer 73e and the second electrode layer 73f are arranged, the third through-hole electrode TH3 is provided in the separation area 73j where the first electrode layer 73e and the second electrode layer 73f are not arranged. The first electrode layer 73e and the second electrode layer 73f and the third through-hole electrode TH3 are also non-contact. Since the through-hole electrodes that electrically connect the electrode layers are provided inside the piezoelectric elements 73a, 73b, 73c and 73d, a stable electrical connection can be ensured, and short circuits and disconnections between the electrode layers are unlikely to occur. In addition, the separation area 73j is necessary whether it is a single layer or a multilayer structure, and by providing the third through-hole electrode TH3 in this space, it is possible to prevent the piezoelectric elements 73a, 73b, 73c and 73d from becoming larger. Furthermore, together with the first through-hole electrode TH1 and the second through-hole electrode TH2, they can be arranged symmetrically, suppressing distorted deformation.

[0044] In this embodiment, the columnar body 74 is a rectangular prism with four side sections, but it is not limited to this; it can also be a triangular prism, a hexagonal prism, or even a cylinder, as long as it is feasible to implement it including the piezoelectric element. In this embodiment, the piezoelectric ultrasonic motor 100 is configured so that the drive shaft 71 is fixed and the columnar body 74 moves, but it may also be configured so that the columnar body 74 is fixed and the drive shaft 71 moves. The cushioning material, which is the felt 75, does not have to be felt; any material that can hold the piezoelectric ultrasonic motor 100 and does not hinder the vibration of the vibrating body is acceptable.

[0045] The piezoelectric elements 73a, 73b, 73c, and 73d are not limited to the configuration of this embodiment. For example, the first through-hole electrode TH1 and the second through-hole electrode TH2 are provided at the diagonal corners of the rectangular piezoelectric element 73a, but they may also be provided at the sides. In this case, it is desirable to provide them symmetrically with respect to the center of the rectangle. However, providing them at the corners has less impact on deformation. As shown in Figures 9A and 9B, the first through-hole electrode TH1 and the second through-hole electrode TH2 may also be provided at the position of the separation portion 73j. In the illustrated example, a part of the first electrode layer 73e is extended toward the separation portion 73j to provide the first through-hole electrode TH1, and a part of the second electrode layer 73f is extended toward the separation portion 73j to provide the second through-hole electrode TH2. Notches 73k are provided in the common electrode layer 73h at positions corresponding to the first through-hole electrode TH1 and the second through-hole electrode TH2. However, since these notches 73k almost overlap with the separation portion 73j when viewed from the stacking direction, they do not affect the overlapping area and shape of the first electrode layer 73e, the second electrode layer 73f, and the common electrode layer 73h. [Explanation of Symbols]

[0046] 5. Optical component driving device; 6. Lens body; 7. Image sensor; 8. Camera equipment; 9. Smartphones; 10 cases; 20 carriers; 20a,21 holes; 20b Annular section; 20c connection; 22,23 Notches; 30 base; 31 Bottom part; 32 side part; 51 York; 52 Hole IC; 53 Magnets; 61 Main guide axis; 62. Sub-guide shaft; 71 Drive shaft; 71a Drive shaft body; 71b proximal end; 72 FPC; 72a Drawer section; 72b Common terminal section; 72R R section; 73a, 73b, 73c, 73d Piezoelectric elements; 73e 1st electrode layer; 73f second electrode layer; 73h common electrode layer; 73j septum; 73k notch; 73s top surface; 73t bottom surface; 73u interface; 73y piezoelectric layer; 74 columnar body; 74a,74b,74c,74d side part; 74e,74f bottom part; 74g through hole; 75 Felt; 100 Piezoelectric ultrasonic motor (motor); TH1 First through-hole electrode; TH2 Second through-hole electrode; TH3 Third Through-Hole Electrode

Claims

1. A piezoelectric element comprising: multiple stacked piezoelectric layers; electrode layers disposed on the upper surface, lower surface, and each interface between the multiple stacked piezoelectric layers; and through-hole electrodes electrically connecting two of the electrode layers provided on different surfaces, The number of piezoelectric layers is odd, The electrode layer comprises a first electrode layer and a second electrode layer formed on the upper surface and the even-numbered interface surfaces from the upper surface side, and a common electrode layer formed on the odd-numbered interface surfaces from the upper surface side and the lower surface. The through-hole electrode comprises a first through-hole electrode connecting the first electrode layers, a second through-hole electrode connecting the second electrode layers, and a third through-hole electrode connecting the common electrode layers. On each surface, the first electrode layer is arranged on one side in a predetermined direction, and the second electrode layer is arranged on the other side opposite to the first electrode layer, separated by a separation portion. The common electrode layer is arranged on almost every surface except for the positions of the first through-hole electrode and the second through-hole electrode and their surroundings, and the third through-hole electrode is arranged at the position of the separation portion. The first through-hole electrode is positioned at the corner of the first electrode layer, The second through-hole electrode is positioned at the corner of the second electrode layer, The first through-hole electrode and the second through-hole electrode are positioned symmetrically with respect to the central part of the entire piezoelectric element when viewed from the stacking direction. The first through-hole electrode and the second through-hole electrode are positioned at both ends of the piezoelectric element on the diagonal when viewed from the stacking direction. Piezoelectric element.

2. The piezoelectric element according to claim 1, wherein the third through-hole electrode is provided in the central part of the entire piezoelectric element when viewed from the stacking direction.

3. The drive shaft and A columnar body having a through hole through which the drive shaft is inserted, The piezoelectric element according to claim 1 is provided on the side surface of the columnar body and drives the drive shaft via the columnar body, A piezoelectric ultrasonic motor in which the predetermined direction is parallel to the axial direction of the drive shaft.

4. The piezoelectric ultrasonic motor according to claim 3, wherein the columnar body is a rectangular parallelepiped, the drive shaft is inserted through a through hole that penetrates between the two bottom surfaces of the rectangular parallelepiped, and the piezoelectric element is provided on each of the four side surfaces of the rectangular parallelepiped.

5. The piezoelectric ultrasonic motor according to claim 4, wherein the common electrode layer of each piezoelectric element is electrically connected to the columnar body, the first electrode layer of each piezoelectric element is subjected to a voltage of the same frequency, the same phase, and the same height, and the second electrode layer is subjected to a voltage of the same frequency, a phase difference of 90 degrees, and the same height as the voltage applied to the first electrode layer.

6. A carrier to support the optical component, An optical member driving device comprising a piezoelectric ultrasonic motor according to claim 3 for driving the carrier.

7. A camera device comprising the optical element driving device described in claim 6.

8. An electronic device comprising the camera device described in claim 7.

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