JP2016040984A - Piezoelectric driving device and driving method thereof, robot and driving method thereof - Google Patents

Abstract

An appropriate configuration of a small piezoelectric drive device is provided. A piezoelectric driving device includes a vibration plate and a piezoelectric vibration member provided on the vibration plate. The piezoelectric vibrating body includes a first electrode, a second electrode, and a piezoelectric body positioned between the first electrode and the second electrode, and the thickness of the piezoelectric body is 50 nm or more and 20 μm or less. is there. [Selection] Figure 1

Description

  The present invention relates to a piezoelectric driving device and a driving method thereof, a robot and a driving method thereof.

  A piezoelectric actuator (piezoelectric driving device) that drives a driven body by vibrating a piezoelectric body is used in various fields because it does not require a magnet or a coil (for example, Patent Document 1). The basic configuration of this piezoelectric drive device is a configuration in which four piezoelectric elements are arranged in two rows and two columns on each of two surfaces of the reinforcing plate, and a total of eight piezoelectric elements are included in the reinforcing plate. It is provided on both sides. Each piezoelectric element is a unit in which a piezoelectric body is sandwiched between two electrodes, and the reinforcing plate is also used as one electrode of the piezoelectric element. One end of the reinforcing plate is provided with a protrusion for rotating the rotor in contact with the rotor as a driven body. When an AC voltage is applied to two of the four piezoelectric elements arranged diagonally, the two piezoelectric elements expand and contract, and the protrusion of the reinforcing plate reciprocates or elliptically moves accordingly. I do. And according to the reciprocating motion or elliptical motion of the protrusion of the reinforcing plate, the rotor as the driven body rotates in a predetermined rotation direction. In addition, the rotor can be rotated in the reverse direction by switching the two piezoelectric elements to which the AC voltage is applied to the other two piezoelectric elements. Patent Document 2 discloses a method for manufacturing a piezoelectric vibrating body having a piezoelectric body. The piezoelectric body manufactured by this manufacturing method is a so-called bulk piezoelectric body, and its thickness is 0.15 mm (150 μm).

JP 2004-320979 A JP 2008-227123 A

  When the piezoelectric drive device is housed and used in a small space (for example, in the joint of a robot), the conventional piezoelectric drive device using a piezoelectric body has a problem that wiring space may be insufficient. Further, when the piezoelectric body is made too thin, the force generated by the piezoelectric element becomes excessively small, and there is a problem that the driven body cannot be driven. Thus, conventionally, an appropriate configuration of a small piezoelectric drive device that can drive a driven body has not been sufficiently studied.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

(1) According to one aspect of the present invention, a piezoelectric driving device is provided. The piezoelectric driving device includes a vibration plate, a first electrode, a second electrode, and a piezoelectric body positioned between the first electrode and the second electrode, and the piezoelectric vibration member provided on the vibration plate The thickness of the piezoelectric element is not less than 50 nm and not more than 20 μm. According to this aspect, since the thickness of the piezoelectric element is set to 50 nm (0.05 μm) or more and 20 μm or less, a small piezoelectric driving device can be realized.

(2) In the piezoelectric drive device of the above aspect, the thickness of the piezoelectric body may be not less than 400 nm and not more than 20 μm. According to this aspect, since the thickness of the piezoelectric body is set to 400 nm or more, the force generated by the piezoelectric element can be increased.

(3) In the piezoelectric driving device according to the above aspect, the piezoelectric vibrator is formed on a substrate, the first electrode formed on the substrate, the piezoelectric body formed on the first electrode, and the piezoelectric body. The second electrode, and the substrate may be bonded to the diaphragm. In order to extract large energy from the piezoelectric element, the mechanical quality factor Qm may be increased so that a large amplitude can be obtained in the resonance state. According to this aspect, since the piezoelectric body, the first electrode, and the second electrode are formed on the substrate, the mechanical quality factor Qm of the piezoelectric driving device can be increased as compared with the case where there is no substrate.

(4) In the piezoelectric driving device according to the above aspect, the substrate may be a silicon substrate. The value of the mechanical quality factor Qm of the piezoelectric body is several thousand, whereas the value of the mechanical quality factor Qm of the silicon substrate is about 100,000. Therefore, according to this embodiment, the mechanical quality factor Qm of the piezoelectric drive device can be increased.

(5) In the piezoelectric driving device according to the aspect described above, the diaphragm has a first surface and a second surface, and the piezoelectric vibrating body is provided on the first surface and the second surface of the diaphragm. May be. According to this aspect, since the piezoelectric elements are provided on the first surface and the second surface of the diaphragm, the driving force of the piezoelectric driving device can be increased.

(6) In the piezoelectric drive device according to the above aspect, the diaphragm may include a protrusion that contacts the driven body. According to this aspect, the driven body can be driven by pushing the driven body by the protrusion.

(7) According to one aspect of the present invention, a robot is provided. The robot includes: a plurality of link units; a joint unit that connects the plurality of link units; and the piezoelectric drive device according to any one of the above aspects, wherein the plurality of link units are rotated by the joint unit. Prepare. According to this embodiment, the piezoelectric driving device can be used for driving the robot.

(8) According to one aspect of the present invention, a method for driving a robot is provided. In this driving method, the piezoelectric driving device is driven by applying a periodically changing voltage between the first electrode and the second electrode of the piezoelectric driving device, and the plurality of link portions are connected to the joint. Rotate at the part.

(9) According to an aspect of the present invention, there is provided a driving method for the piezoelectric driving device according to the above aspect. In this driving method, a voltage that periodically changes between the first electrode and the second electrode, and the direction of the electric field applied to the piezoelectric body is changed from one of the electrodes to the other. A voltage that is a pulsating flow in one direction toward the electrode is applied. According to this aspect, since the voltage applied to the piezoelectric body is only in one direction, the durability of the piezoelectric body can be improved.

  The present invention can be realized in various forms. For example, in addition to a piezoelectric driving device, a driving method of the piezoelectric driving device, a manufacturing method of the piezoelectric driving device, a robot equipped with the piezoelectric driving device, and a piezoelectric driving device. It can be realized in various forms such as a driving method of a robot to be mounted, a liquid feeding pump, and a medication pump.

The top view and sectional drawing which show schematic structure of the piezoelectric drive device of 1st Embodiment. The top view of a diaphragm. It is explanatory drawing which shows the electrical connection state of a piezoelectric drive device and a drive circuit. It is explanatory drawing which shows the example of operation | movement of a piezoelectric drive device. FIG. 3 is a detailed cross-sectional view of the piezoelectric driving device when cut by a cutting plane parallel to the longitudinal direction. The manufacturing flowchart of a piezoelectric drive device. Explanatory drawing which shows the manufacturing process of the piezoelectric vibrating body in step S100 of FIG. Explanatory drawing which shows an example of the wiring of a piezoelectric drive device and a drive circuit. Sectional drawing of the piezoelectric drive device as other embodiment of this invention. Sectional drawing of the piezoelectric drive device of other embodiment. The top view of the piezoelectric drive device of other embodiment. Explanatory drawing which shows an example of the robot using a piezoelectric drive device. Explanatory drawing of the wrist part of a robot. Explanatory drawing which shows an example of the liquid feeding pump using a piezoelectric drive device.

First embodiment:
FIG. 1A is a plan view showing a schematic configuration of the piezoelectric driving device 10 according to the first embodiment of the present invention, and FIG. 1B is a sectional view taken along the line BB. The piezoelectric driving device 10 includes a vibration plate 200 and two piezoelectric vibrations disposed on both surfaces (first surface 211 (also referred to as “front surface”) and second surface 212 (also referred to as “back surface”) of the vibration plate 200. A body 100. The piezoelectric vibrating body 100 includes a substrate 120, a first electrode 130 formed on the substrate 120, a piezoelectric body 140 formed on the first electrode 130, and a second electrode formed on the piezoelectric body 140. An electrode 150. The first electrode 130 and the second electrode 150 sandwich the piezoelectric body 140. The two piezoelectric vibrators 100 are arranged symmetrically about the diaphragm 200. Since the two piezoelectric vibrators 100 have the same configuration, the configuration of the piezoelectric vibrator 100 on the upper side of the diaphragm 200 will be described below unless otherwise specified.

The substrate 120 of the piezoelectric vibrating body 100 is used as a substrate for forming the first electrode 130, the piezoelectric body 140, and the second electrode 150 by a film forming process. The substrate 120 also has a function as a diaphragm that performs mechanical vibration. The substrate 120 can be formed of, for example, Si, Al ₂ O ₃ , ZrO ₂ or the like. As the Si substrate 120, for example, a Si wafer for semiconductor manufacturing can be used. In this embodiment, the planar shape of the substrate 120 is a rectangle. The thickness of the substrate 120 is preferably in the range of 10 μm to 100 μm, for example. If the thickness of the substrate 120 is 10 μm or more, the substrate 120 can be handled relatively easily during the film forming process on the substrate 120. If the thickness of the substrate 120 is 100 μm or less, the substrate 120 can be easily vibrated according to the expansion and contraction of the piezoelectric body 140 formed of a thin film.

  The first electrode 130 is formed as one continuous conductor layer formed on the substrate 120. On the other hand, as shown in FIG. 1A, the second electrode 150 is divided into five conductor layers 150a to 150e (also referred to as “second electrodes 150a to 150e”). The second electrode 150e at the center is formed in a rectangular shape covering almost the entire length of the substrate 120 at the center in the width direction of the substrate 120. The other four second electrodes 150 a, 150 b, 150 c, and 150 d have the same planar shape and are formed at the four corner positions of the substrate 120. In the example of FIG. 1, both the first electrode 130 and the second electrode 150 have a rectangular planar shape. The first electrode 130 and the second electrode 150 are thin films formed by sputtering, for example. As a material of the first electrode 130 and the second electrode 150, for example, any material having high conductivity such as Al (aluminum), Ni (nickel), Au (gold), Pt (platinum), Ir (iridium) or the like is used. Is available. Instead of the first electrode 130 being one continuous conductor layer, the first electrode 130 may be divided into five conductor layers having substantially the same planar shape as the second electrodes 150a to 150e. In addition, wiring (or wiring layer and insulating layer) for electrical connection between the second electrodes 150a to 150e, and electrical connection between the first electrode 130 and the second electrodes 150a to 150e and the drive circuit The wiring for the purpose (or the wiring layer and the insulating layer) is not shown in FIG.

  The piezoelectric body 140 is formed as five piezoelectric layers having substantially the same planar shape as the second electrodes 150a to 150e. Alternatively, the piezoelectric body 140 may be formed as one continuous piezoelectric layer having substantially the same planar shape as the first electrode 130. Five piezoelectric elements 110a to 110e (FIG. 1A) are configured by a laminated structure of the first electrode 130, the piezoelectric body 140, and the second electrodes 150a to 150e.

The piezoelectric body 140 is a thin film formed by, for example, a sol-gel method or a sputtering method. As a material of the piezoelectric body 140, any material exhibiting a piezoelectric effect such as ceramics having an ABO ₃ type perovskite structure can be used. Examples of ceramics having an ABO ₃ type perovskite structure include lead zirconate titanate (PZT), barium titanate, lead titanate, potassium niobate, lithium niobate, lithium tantalate, sodium tungstate, zinc oxide, titanium Barium strontium acid (BST), strontium bismuth tantalate (SBT), lead metaniobate, lead zinc niobate, lead scandium niobate, or the like can be used. It is also possible to use a material exhibiting a piezoelectric effect other than ceramic, such as polyvinylidene fluoride and quartz. The thickness of the piezoelectric body 140 is preferably in the range of, for example, 50 nm (0.05 μm) to 20 μm. A thin film of the piezoelectric body 140 having a thickness in this range can be easily formed using a film forming process. If the thickness of the piezoelectric body 140 is 0.05 μm or more, a sufficiently large force can be generated according to the expansion and contraction of the piezoelectric body 140. If the thickness of the piezoelectric body 140 is 20 μm or less, the piezoelectric driving device 10 can be sufficiently downsized.

  FIG. 2 is a plan view of the diaphragm 200. The diaphragm 200 has a rectangular-shaped vibrating body portion 210 and three connecting portions 220 that extend from the left and right long sides of the vibrating body portion 210, respectively. Two attachment portions 230 are connected to each other. In FIG. 2, the vibrating body portion 210 is hatched for convenience of illustration. The attachment portion 230 is used for attaching the piezoelectric driving device 10 to another member with a screw 240. The diaphragm 200 can be formed of a metal material such as stainless steel, aluminum, an aluminum alloy, titanium, a titanium alloy, copper, a copper alloy, or an iron-nickel alloy, for example.

  The piezoelectric vibrating body 100 (FIG. 1) is bonded to the upper surface (first surface) and the lower surface (second surface) of the vibrating body portion 210 using an adhesive. The ratio of the length L to the width W of the vibrating body part 210 is preferably L: W = about 7: 2. This ratio is a preferable value for performing ultrasonic vibration (described later) in which the vibrating body portion 210 bends left and right along the plane. The length L of the vibrating body portion 210 can be set in a range of, for example, 3.5 mm or more and 30 mm or less, and the width W can be set in a range of, for example, 1 mm or more and 8 mm or less. In addition, in order for the vibrating body part 210 to perform ultrasonic vibration, the length L is preferably set to 50 mm or less. The thickness of the vibrating body part 210 (thickness of the vibration plate 200) can be in the range of, for example, 50 μm or more and 700 μm or less. If the thickness of the vibrating body portion 210 is 50 μm or more, the vibrating body portion 210 has sufficient rigidity to support the piezoelectric vibrating body 100. Further, if the thickness of the vibrating body portion 210 is 700 μm or less, a sufficiently large deformation can be generated according to the deformation of the piezoelectric vibrating body 100.

On one short side of the diaphragm 200, a protrusion 20 (also referred to as “contact portion” or “action portion”) is provided. The protrusion 20 is a member that is in contact with the driven body and applies a force to the driven body. The protrusion 20 is preferably formed of a durable material such as ceramics (for example, Al ₂ O ₃ ).

  FIG. 3 is an explanatory diagram showing an electrical connection state between the piezoelectric driving device 10 and the driving circuit 300. Among the five second electrodes 150a to 150e, a pair of diagonal second electrodes 150a and 150d are electrically connected to each other via the wiring 151, and another diagonal pair of second electrodes 150b and 150c. Are also electrically connected to each other via the wiring 152. These wirings 151 and 152 may be formed by a film forming process, or may be realized by wire-like wiring. Three second electrodes 150b, 150e, and 150d on the right side of FIG. 3 and the first electrode 130 (FIG. 1) are electrically connected to the drive circuit 300 via wirings 310, 312, 314, and 320. . The drive circuit 300 ultrasonically vibrates the piezoelectric drive device 10 by applying an alternating voltage or a pulsating voltage that periodically changes between the pair of second electrodes 150a and 150d and the first electrode 130, It is possible to rotate the rotor (driven body) in contact with the protrusion 20 in a predetermined rotation direction. Here, the “pulsating voltage” means a voltage obtained by adding a DC offset to an AC voltage, and the direction of the voltage (electric field) is one direction from one electrode to the other electrode. In addition, by applying an AC voltage or a pulsating current voltage between the other pair of second electrodes 150b and 150c and the first electrode 130, it is possible to rotate the rotor in contact with the protrusion 20 in the reverse direction. is there. Such voltage application is performed simultaneously on the two piezoelectric vibrating bodies 100 provided on both surfaces of the diaphragm 200. Note that the wirings (or wiring layers and insulating layers) constituting the wirings 151, 152, 310, 312, 314, and 320 shown in FIG. 3 are not shown in FIG.

  FIG. 4 is an explanatory diagram illustrating an example of the operation of the piezoelectric driving device 10. The protrusion 20 of the piezoelectric driving device 10 is in contact with the outer periphery of the rotor 50 as a driven body. In the example shown in FIG. 4, the drive circuit 300 (FIG. 3) applies an AC voltage or a pulsating voltage between the pair of second electrodes 150a and 150d and the first electrode 130, and the piezoelectric elements 110a and 110d. Expands and contracts in the direction of arrow x in FIG. In response to this, the vibrating body portion 210 of the piezoelectric driving device 10 is bent in the plane of the vibrating body portion 210 and deformed into a meandering shape (S-shape), and the tip of the protrusion 20 reciprocates in the direction of the arrow y. Or elliptical motion. As a result, the rotor 50 rotates around the center 51 in a predetermined direction z (clockwise direction in FIG. 4). The three connection portions 220 (FIG. 2) of the diaphragm 200 described with reference to FIG. 2 are provided at the positions of the vibration nodes (interferences) of the vibration body portion 210. When the drive circuit 300 applies an AC voltage or a pulsating voltage between the other pair of second electrodes 150b and 150c and the first electrode 130, the rotor 50 rotates in the reverse direction. If the same voltage as the pair of second electrodes 150a and 150d (or the other pair of second electrodes 150b and 150c) is applied to the center second electrode 150e, the piezoelectric driving device 10 expands and contracts in the longitudinal direction. The force applied to the rotor 50 from the protrusion 20 can be further increased. Such an operation of the piezoelectric driving device 10 (or the piezoelectric vibrating body 100) is described in the above-mentioned prior art document 1 (Japanese Patent Laid-Open No. 2004-320979 or corresponding US Pat. No. 7,224,102). The disclosure of which is incorporated by reference.

  FIG. 5 is a cross-sectional view showing an example of the cross-sectional structure shown in FIG. The piezoelectric vibrating body 100 includes a substrate 120, an insulating layer 125, a first electrode 130, a piezoelectric body 140, a second electrode 150, an insulating layer 160, and lead electrodes 171 and 172. In FIG. 5, the plurality of second electrodes 150 and the plurality of lead electrodes 171 and 172 are distinguished from each other by adding a suffix “c” or “d”. In FIG. 5, the wirings 151 and 152 shown in FIG. 3 are not shown.

  The insulating layer 125 is formed on the substrate 120 and insulates the substrate 120 from the first electrode 130. The first electrode 130 is formed on the insulating layer 125. The piezoelectric body 140 is formed on the first electrode 130. The second electrode 150 is formed on the piezoelectric body 140. The insulating layer 160 is formed on the second electrode 150. The insulating layer 160 has an opening (contact hole) at a part thereof so that the first lead electrode 171 can contact the first electrode 130 and the second lead electrode 172 can contact the second electrode 150. Yes. The first lead electrode 171 is formed on the insulating layer 160 and is in contact with the first electrode 130. The second lead electrode 172 is formed on the insulating layer 160 and is in contact with the second electrode 150. The two lead electrodes 171 and 172 are not directly connected to each other. In FIG. 5, for convenience of illustration, the second lead electrodes 172c and 172d are formed at positions close to the boundary between the piezoelectric element 110c and the piezoelectric element 110d. The second lead electrodes 172c and 172d may be formed on both ends in the longitudinal direction of the vibration plate 200, respectively. In this case, if the positions of the first lead electrodes 171c and 171d and the second lead electrodes 172c and 172d are different from each other in the width direction (short direction of the diaphragm 200), they are not connected to each other. The second lead electrodes 172c and 172d may extend to a region where the piezoelectric body 140 does not exist below. If the wirings 151, 152, and 314 are connected to the second lead electrode in a region where the piezoelectric body 140 does not exist in the lower portion, the electrostatic breakdown of the piezoelectric body 140 due to the connection of the wiring hardly occurs.

  FIG. 6 is an explanatory diagram showing a manufacturing flowchart of the piezoelectric driving device 10. In step S <b> 100, the piezoelectric vibrating body 100 is formed by forming the piezoelectric element 110 on the substrate 120. At this time, for example, a Si wafer can be used as the substrate 120. A plurality of piezoelectric vibrators 100 can be formed on one Si wafer. Further, since Si has a large mechanical quality factor Qm of about 100,000, the mechanical quality factor Qm of the piezoelectric vibrator 100 and the piezoelectric driving device 10 can be increased. In step S <b> 200, the substrate 120 on which the piezoelectric vibrating body 100 is formed is diced and divided into individual piezoelectric vibrating bodies 100. Note that before the substrate 120 is diced, the back surface of the substrate 120 may be polished so that the substrate 120 has a desired thickness. In step S300, the two piezoelectric vibrators 100 are bonded to both surfaces of the diaphragm 200 with an adhesive. In step S400, the wiring layer of the piezoelectric vibrating body 100 and the drive circuit are electrically connected by wiring.

FIG. 7 is an explanatory diagram showing a manufacturing process of the piezoelectric vibrating body 100 in step S100 of FIG. FIG. 7 shows a process of forming the piezoelectric element 110d shown in the upper part of the right half of FIG. In step S110, the substrate 120 is prepared, and the insulating layer 125 is formed on the surface of the substrate 120. As the insulating layer 125, for example, an SiO ₂ layer formed by thermally oxidizing the surface of the substrate 120 can be used. In addition, an organic material such as alumina (Al ₂ O ₃ ), acrylic, or polyimide can be used for the insulating layer. Note that in the case where the substrate 120 is an insulator, the step of forming the insulating layer 125 can be omitted.

  In step S <b> 120, the first electrode 130 is formed on the insulating layer 125. The first electrode 130 can be formed by sputtering, for example.

  In step S <b> 130, the piezoelectric body 140 is formed on the first electrode 130. Specifically, the piezoelectric body 140 can be formed using, for example, a sol-gel method. That is, a sol-gel solution of a piezoelectric material is dropped on the substrate 120 (first electrode 130), and the substrate 120 is rotated at a high speed to form a sol-gel solution thin film on the first electrode 130. Thereafter, the first layer of the piezoelectric material is formed on the first electrode 130 by calcining at a temperature of 200 to 300 ° C. Thereafter, the piezoelectric layer is formed on the first electrode 130 to a desired thickness by repeating the sol-gel solution dripping, high-speed rotation, and calcination cycles a plurality of times. The thickness of one layer of the piezoelectric body formed in one cycle is about 50 nm to 150 nm, although it depends on the viscosity of the sol-gel solution and the rotation speed of the substrate 120. After the piezoelectric layer is formed to a desired thickness, the piezoelectric body 140 is formed by sintering at a temperature of 600 ° C. to 1000 ° C. If the thickness of the sintered piezoelectric body 140 is 50 nm (0.05 μm) or more and 20 μm or less, a small piezoelectric drive device 10 can be realized. If the thickness of the piezoelectric body 140 is 0.05 μm or more, a sufficiently large force can be generated according to the expansion and contraction of the piezoelectric body 140. If the thickness of the piezoelectric body 140 is 20 μm or less, a sufficiently large force can be generated even if the voltage applied to the piezoelectric body 140 is 600 V or less. As a result, the drive circuit 300 for driving the piezoelectric drive device 10 can be configured with inexpensive elements. The thickness of the piezoelectric body may be 400 nm or more. In this case, the force generated by the piezoelectric element can be increased. The temperature and time for calcining and sintering are examples, and are appropriately selected depending on the piezoelectric material.

  In the case of sintering after forming a thin film of piezoelectric material using the sol-gel method, (a) it is easier to form a thin film as compared with a conventional sintering method in which raw material powders are mixed and sintered. (B) It is easy to crystallize by aligning the lattice direction, and (c) it is possible to improve the breakdown voltage of the piezoelectric body.

  In step S <b> 140, the second electrode 150 is formed on the piezoelectric body 140. The formation of the second electrode 150 can be performed by sputtering in the same manner as the first electrode.

  In step S150, the second electrode 150 and the piezoelectric body 140 are patterned. In the present embodiment, the second electrode 150 and the piezoelectric body 140 are patterned by ion milling using an argon ion beam. By controlling the ion milling time, it is possible to pattern only the second electrode 150 and the piezoelectric body 140 and not pattern the first electrode 130. Instead of patterning using ion milling, patterning may be performed by any other patterning method (for example, dry etching using a chlorine-based gas).

In step S <b> 160, the insulating layer 160 is formed on the first electrode 130 and the second electrode 150. As the insulating layer 160, a phosphorus-containing silicon oxide film (PSG film), a boron-phosphorus-containing silicon oxide film (BPSG film), an NSG film (a silicon oxide film not containing impurities such as boron and phosphorus), a silicon nitride film (Si ₃ N ₄ film) or the like. The insulating layer 160 can be formed by, for example, a CVD method. After the formation of the insulating layer 160, patterning for forming contact holes 163 and 165 between the first electrode 130 and the second electrode 150 is performed.

  In step S170, a conductor layer for the lead electrode is formed and patterned. This conductor layer can be formed of aluminum, for example, and is formed by sputtering. Thereafter, the first lead electrode 171 and the second lead electrode 172 are formed by patterning the conductor layer. The first lead electrode 171 is connected to the first electrode 130, and the second lead electrode 172 is connected to the second electrode 150. When the first electrode 130 of the piezoelectric elements 110a to 110e forms one continuous conductor layer, the second lead electrode 172 is formed on the other piezoelectric elements 110a, 110b, 110c, and 110e. It does not have to be. The second lead electrode 172 may extend to a region where the piezoelectric body 140 does not exist below. If the wirings 151, 152, and 314 are connected to the second lead electrode 172 in a region where the piezoelectric body 140 does not exist below, the influence of the connection of the wiring does not reach the piezoelectric body 140. Further, both the first lead electrode 171 and the second lead electrode 172 may remain above the insulating layer 160. When a wiring layer is formed on the vibration plate 200 and the piezoelectric element 110 is disposed between the substrate 120 and the vibration plate 200, the wiring layer of the vibration plate 200 is interposed between the first lead electrode 171 and the second lead electrode 172. Can be easily connected electrically.

  Thereafter, although not shown, a passivation film is formed on the first lead electrode 171 and the second lead electrode 172. The passivation film can be formed using, for example, SiN or polyimide. Then, openings (contact holes) for connecting the first lead electrode 171 and the second lead electrode 172 to the wirings 151, 152, 310, 312, 314, and 320 (FIG. 3) are formed in the passivation film.

  FIG. 8 is an explanatory diagram illustrating an example of wiring between the piezoelectric driving device 10 and the driving circuit 300. Here, the wiring connection state on the front surface side and the back surface side of the piezoelectric driving device 10 is shown. For convenience of illustration, the sizes of the electrodes 150a to 150e and the like are slightly different from those in FIG. On the front and back surfaces of the piezoelectric driving device, the second electrodes 150a, 150b, 150c, 150d, and 150e, the first lead electrodes 171a, 171b, 171c, 171d, and 171e, and the second lead electrodes 172a, 172b, and 172c, respectively. , 172d, 172e. Here, in order to distinguish the piezoelectric elements 110a to 110e, suffixes a, b, c, d, and e are added to the end of the second electrode 150, the first lead electrode 171, and the second lead electrode 172. When the first electrode 130 forms one continuous conductor layer, the first lead electrodes 171a, 171b, 171c, and 171e indicated by broken lines in FIG. 8 do not have to be formed. .

Wirings connecting the electrodes of the piezoelectric driving device 10 are wired as follows.
The wiring 151 connects the second lead electrodes 172a and 172d on the surface side.
The wiring 152 connects the second lead electrodes 172b and 172c on the surface side.
The wiring 182a connects the second lead electrode 172a on the front surface side and the second lead electrode 172a on the rear surface side.
The wiring 182b connects the second lead electrode 172b on the front surface side and the second lead electrode 172b on the rear surface side.
The wiring 182c connects the second lead electrode 172c on the front surface side and the second lead electrode 172c on the rear surface side.
The wiring 182d connects the second lead electrode 172d on the front surface side and the second lead electrode 172d on the rear surface side.

Each electrode of the piezoelectric drive device 10 and the drive circuit are connected as follows.
The wiring 310 connects the drive circuit 300 and the second lead electrode 172b on the surface side.
The wiring 312 connects the driving circuit 300 to the second lead electrode 172e on the front surface side and the second lead electrode 172e on the rear surface side.
The wiring 314 connects the drive circuit 300 and the second lead electrode 172d on the surface side.
The wiring 320 connects the drive circuit 300 to the first lead electrode 171d on the front surface side and the first lead electrode 171d on the rear surface side.

  When an AC voltage or a pulsating voltage is applied between the wirings 310 and 320, the piezoelectric elements 110b and 110c (FIG. 1A) can be driven as described above. In addition, when an AC voltage or a pulsating voltage is applied between the wirings 314 and 320, the piezoelectric elements 110a and 110d (FIG. 1A) can be driven. When an AC voltage or a pulsating voltage is applied between the wirings 312 and 320, the piezoelectric element 110e (FIG. 1A) can be driven.

  As described above, according to this embodiment, since the thickness of the piezoelectric body 140 is set to 50 nm (0.05 μm) or more and 20 μm or less, a small piezoelectric driving device 10 can be realized. If the thickness of the piezoelectric body 140 is 0.05 μm or more, a sufficiently large force can be generated according to the expansion and contraction of the piezoelectric body 140. If the thickness of the piezoelectric body 140 is 20 μm or less, a sufficiently large force can be generated even if the voltage applied to the piezoelectric body 140 is 600 V or less. Therefore, the drive circuit 300 for driving the piezoelectric drive device 10 can be configured with inexpensive elements. However, in practice, the voltage applied to the piezoelectric body 140 is sufficient in the range of 20 to 40V. The thickness of the piezoelectric body may be 400 nm or more. In this case, the force generated by the piezoelectric element can be increased.

  Further, according to the present embodiment, since the piezoelectric elements (110a to 110e) are formed on the substrate 120, the mechanical quality factor Qm of the piezoelectric driving device 10 is set to be smaller than that when the substrate 120 is not provided. Can be big. In particular, since the mechanical quality factor Qm value of the Si substrate is about 100,000, the mechanical quality factor Qm of the piezoelectric driving device 10 can be increased by using the Si substrate 120.

  If the piezoelectric body 140 is formed by a sol-gel method, it is preferable because a thin piezoelectric body can be easily formed. In addition, since it is easy to align the lattice direction of the crystal of the piezoelectric body, it is preferable in that the deformation of the shape of the piezoelectric body when the same voltage is applied can be increased and the breakdown voltage can be increased. The piezoelectric body 140 may be formed by a sputtering method. The same effect as the sol-gel method can be obtained also by the sputtering method.

-Other embodiments of the piezoelectric drive:
FIG. 9 is a cross-sectional view of a piezoelectric drive device 10a as another embodiment of the present invention, and corresponds to FIG. 1B of the first embodiment. In the piezoelectric driving device 10a, the piezoelectric vibrating body 100 is disposed on the diaphragm 200 in a state where the top and bottom of FIG. That is, here, the second electrode 150 is disposed close to the diaphragm 200 and the substrate 120 is disposed farthest from the diaphragm 200. In FIG. 9, as in FIG. 1B, wiring (or a wiring layer and an insulating layer) for electrical connection between the second electrodes 150a to 150e, the first electrode 130, and the second electrode Illustration of wirings (or wiring layers and insulating layers) for electrical connection between 150a to 150e and the drive circuit is omitted. This piezoelectric drive device 10a can also achieve the same effect as that of the first embodiment.

  FIG. 10 is an explanatory view showing a manufacturing process of the piezoelectric driving device 10a shown in FIG. In step S510, the diaphragm 200 is prepared and the insulating layer 202 is formed. The insulating layer 202 can be formed using, for example, an insulating resin such as polyimide. In step S520, the wiring layer 204 is formed on the insulating layer 202, and the wiring layer 204 is patterned. The wiring layer 204 includes a first wiring and a second wiring. As the wiring layer 204, copper or aluminum can be used. In step S530, the insulating layer 206 is formed on the wiring layer 204, and the opening is patterned. The insulating layer 206 can be formed using, for example, a solder resist.

  In step S540, the piezoelectric vibrators 100 individually created in step S200 (FIG. 7) of FIG. 6 are attached to both surfaces of the diaphragm 200. At this time, the conductive member 208 is disposed between the wiring layer 204 and the first lead electrode 171 and the second lead electrode 172, and is in electrical contact via the conductive member 208. Specifically, the first wiring of the wiring layer 204 and the first lead electrode 171 are brought into electrical contact, and the second wiring of the wiring layer 204 and the second lead electrode 172 are brought into electrical contact. By using the conductive member 208, even if there is a step between the wiring layer 204 of the diaphragm 200 and the first lead electrode 171 and the second lead electrode 172 of the piezoelectric vibrator 100, the step is reduced. Can be brought into electrical contact. As the conductive member 208, for example, a micro bump or a conductive paste can be used. In FIG. 10E, the first surface side shows a state where the piezoelectric vibrating body 100 is attached, and the second surface side shows a state immediately before the piezoelectric vibrating body 100 is attached. Note that the above-described passivation film 180 is formed on the piezoelectric vibrator 100 shown in FIG. The passivation film 180 protects the periphery of the first lead electrode 171 and the second lead electrode 172 and suppresses an electrical short circuit between the first lead electrode 171 and the second lead electrode 172 and other members. In this embodiment, the shape of the second lead electrode 172 is extended to a region where the piezoelectric body 140 does not exist in the lower portion, but it may not be extended. This is because the second lead electrode 172 does not need to extend to a region where the piezoelectric body 140 does not exist in the lower part because it is connected to the wiring layer 204 of the diaphragm 200 via the conductive member 208.

  Thereafter, the wiring layer 204 and the drive circuit 300 (FIG. 8) are connected by wirings 310, 312, 314, and 320. That is, in this embodiment, the wirings 310, 312, 314, 320 are not directly wired to the first lead electrode 171 and the second lead electrode 172, but are wired via the wiring layer 204. Therefore, it is not necessary to directly wire the vibrating piezoelectric vibrating body 100, and even if the piezoelectric vibrating body 100 vibrates, the wiring is difficult to come off. In the present embodiment, the wirings 310, 312, 314, and 320 are connected after the piezoelectric vibrating body 100 is attached to the vibration plate 200, but the wirings 310, 312, 314, and 320 are connected to the piezoelectric vibrating body 100 first. Later, the piezoelectric vibrating body 100 may be attached to the vibration plate 200.

  FIG. 11A is a plan view of a piezoelectric driving device 10b as still another embodiment of the present invention, and corresponds to FIG. 1A of the first embodiment. 11A to 11C, for convenience of illustration, the connection part 220 and the attachment part 230 of the diaphragm 200 are not shown. In the piezoelectric driving device 10b of FIG. 11A, the pair of second electrodes 150b and 150c are omitted. The piezoelectric driving device 10b can also rotate the rotor 50 in one direction z as shown in FIG. Since the same voltage is applied to the three second electrodes 150a, 150e, and 150d in FIG. 11A, these three second electrodes 150a, 150e, and 150d are formed as one continuous electrode layer. May be.

  FIG. 11B is a plan view of a piezoelectric driving device 10c as still another embodiment of the present invention. In the piezoelectric driving device 10c, the second electrode 150e at the center in FIG. 1A is omitted, and the other four second electrodes 150a, 150b, 150c, and 150d have a larger area than that in FIG. Is formed. This piezoelectric drive device 10c can also achieve substantially the same effect as in the first embodiment.

  FIG. 11C is a plan view of a piezoelectric drive device 10d as still another embodiment of the present invention. In the piezoelectric driving device 10d, the four second electrodes 150a, 150b, 150c, and 150d in FIG. 1A are omitted, and one second electrode 150e is formed with a large area. The piezoelectric driving device 10d only expands and contracts in the longitudinal direction, but can apply a large force from the protrusion 20 to the driven body (not shown).

  As can be understood from FIG. 1 and FIGS. 11A to 11C, at least one electrode layer can be provided as the second electrode 150 of the piezoelectric vibrating body 100. However, if the second electrode 150 is provided at a diagonal position of the rectangular piezoelectric vibrator 100 as in the embodiment shown in FIGS. 1 and 11A and 11B, the piezoelectric vibrator 100 and The diaphragm 200 is preferable in that it can be deformed into a meandering shape that bends in the plane.

-Embodiments of a device using a piezoelectric drive:
The piezoelectric drive device 10 described above can apply a large force to the driven body by utilizing resonance, and can be applied to various devices. The piezoelectric driving device 10 is, for example, a robot (including an electronic component conveying device (IC handler)), a dosing pump, a calendar feeding device for a clock, and a printing device (for example, a paper feeding mechanism. However, a piezoelectric driving device used for a head. Then, since the diaphragm is not resonated, it cannot be applied to the head. Hereinafter, representative embodiments will be described.

  FIG. 12 is an explanatory diagram showing an example of a robot 2050 using the piezoelectric driving device 10 described above. The robot 2050 includes a plurality of link portions 2012 (also referred to as “link members”) and an arm 2010 (“a” that includes a plurality of joint portions 2020 that connect the link portions 2012 in a rotatable or bendable state. It is also called “arm”. Each joint portion 2020 includes the above-described piezoelectric drive device 10, and the joint portion 2020 can be rotated or bent by an arbitrary angle using the piezoelectric drive device 10. A robot hand 2000 is connected to the tip of the arm 2010. The robot hand 2000 includes a pair of grip portions 2003. The robot hand 2000 also has a built-in piezoelectric driving device 10, and the piezoelectric driving device 10 can be used to open and close the gripping unit 2003 to grip an object. The piezoelectric drive device 10 is also provided between the robot hand 2000 and the arm 2010, and the robot hand 2000 can be rotated with respect to the arm 2010 using the piezoelectric drive device 10.

  FIG. 13 is an explanatory diagram of the wrist portion of the robot 2050 shown in FIG. The wrist joint portion 2020 holds the wrist rotation portion 2022, and the wrist link portion 2012 is attached to the wrist rotation portion 2022 so as to be rotatable around the central axis O of the wrist rotation portion 2022. . The wrist rotation unit 2022 includes the piezoelectric driving device 10, and the piezoelectric driving device 10 rotates the wrist link unit 2012 and the robot hand 2000 around the central axis O. The robot hand 2000 is provided with a plurality of gripping units 2003. The proximal end portion of the grip portion 2003 can be moved in the robot hand 2000, and the piezoelectric driving device 10 is mounted on the base portion of the grip portion 2003. For this reason, by operating the piezoelectric driving device 10, it is possible to move the gripping part 2003 and grip the object.

  The robot is not limited to a single-arm robot, and the piezoelectric driving device 10 can be applied to a multi-arm robot having two or more arms. Here, inside the wrist joint 2020 and the robot hand 2000, in addition to the piezoelectric driving device 10, a power line for supplying power to various devices such as a force sensor and a gyro sensor, a signal line for transmitting a signal, and the like And requires a lot of wiring. Therefore, it is very difficult to arrange the wiring inside the joint portion 2020 and the robot hand 2000. However, since the piezoelectric drive device 10 of the above-described embodiment can reduce the drive current compared to a normal electric motor or a conventional piezoelectric drive device, the joint portion 2020 (particularly, the joint portion at the tip of the arm 2010) or a robot hand. Wiring can be arranged even in a small space such as 2000.

  FIG. 14 is an explanatory view showing an example of a liquid feed pump 2200 using the piezoelectric driving device 10 described above. The liquid feed pump 2200 includes a reservoir 2211, a tube 2212, the piezoelectric driving device 10, a rotor 2222, a deceleration transmission mechanism 2223, a cam 2202, a plurality of fingers 2213, 2214, 2215, 2216, and a case 2230. 2217, 2218, and 2219 are provided. The reservoir 2211 is a storage unit for storing a liquid to be transported. The tube 2212 is a tube for transporting the liquid sent out from the reservoir 2211. The protrusion 20 of the piezoelectric driving device 10 is provided in a state of being pressed against the side surface of the rotor 2222, and the piezoelectric driving device 10 rotationally drives the rotor 2222. The rotational force of the rotor 2222 is transmitted to the cam 2202 via the deceleration transmission mechanism 2223. Fingers 2213 to 2219 are members for closing the tube 2212. When the cam 2202 rotates, the fingers 2213 to 2219 are sequentially pushed outward in the radial direction by the protrusion 2202A of the cam 2202. The fingers 2213 to 2219 close the tube 2212 in order from the upstream side in the transport direction (reservoir 2211 side). Thereby, the liquid in the tube 2212 is transported to the downstream side in order. In this way, it is possible to realize a small liquid feed pump 2200 that can deliver an extremely small amount with high accuracy and that is small. In addition, arrangement | positioning of each member is not restricted to what was illustrated. Further, a member such as a finger may not be provided, and a ball or the like provided on the rotor 2222 may close the tube 2212. The liquid feed pump 2200 as described above can be used for a medication device that administers a drug solution such as insulin to the human body. Here, by using the piezoelectric driving device 10 according to the above-described embodiment, the driving current is smaller than that of the conventional piezoelectric driving device, so that the power consumption of the dosing device can be suppressed. Therefore, it is particularly effective when the medication apparatus is battery-driven.

・ Modification:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

・ Modification 1:
In the above embodiment, the first electrode 130, the piezoelectric body 140, and the second electrode 150 are formed on the substrate 120. However, the substrate 120 is omitted, and the first electrode 130 and the piezoelectric material are formed on the vibration plate 200. The body 140 and the second electrode 150 may be formed.

Modification 2
In the above embodiment, one piezoelectric vibrating body 100 is provided on each of both surfaces of the vibration plate 200, but one of the piezoelectric vibrating bodies 100 can be omitted. However, providing the piezoelectric vibrating bodies 100 on both surfaces of the diaphragm 200 is preferable in that it is easier to deform the diaphragm 200 into a meandering shape bent in the plane.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

10, 10a, 10b, 10c, 10d, 10e ... Piezoelectric drive device 12 ... Tube 20 ... Projection (contact part, action part)
50 ... Rotor (driven body)
51 ... Center of driven body 100 ... Piezoelectric vibrator 110a, 110b, 110e ... Piezoelectric element 120 ... Substrate 125 ... Insulating layer 130 ... First electrode 140 ... Piezoelectric body 150, 150a, 150b, 150c, 150d, 150e ... Second Electrodes 151, 152 ... Wiring 160 ... Insulating layer 163, 165 ... Contact hole 171, 171a, 171b, 171c, 171d, 171e ... First lead electrode 172, 172a, 172b, 172c, 172d, 172e ... Second lead electrode 180 ... Passivation film 181a, 181b, 182c, 181d ... Wiring 200 ... Vibration plate 202 ... Insulating layer 204 ... Wiring layer 206 ... Insulating layer 208 ... Conductive member 210 ... Vibrating body part 211 ... First surface 212 ... Second surface 220 ... Connection Part 230 ... Mounting part 240 ... Screw 300 ... Drive Routes 310, 312, 314, 320 ... Wiring 2000 ... Robot hand 2003 ... Grasping part 2010 ... Arm 2012 ... Link part 2020 ... Joint part 2022 ... Wrist rotation part 2050 ... Robot 2200 ... Liquid feed pump 2202 ... Cam 2202A ... Projection part 2211 ... Reservoir 2212 ... Tube 2213 ... Finger 2222 ... Rotor 2223 ... Deceleration transmission mechanism 2230 ... Case

Claims (9)

A diaphragm,
A first electrode, a second electrode, a piezoelectric body positioned between the first electrode and the second electrode, and a piezoelectric vibrating body provided on the diaphragm;
With
The piezoelectric driving device, wherein the piezoelectric body has a thickness of 50 nm or more and 20 μm or less. The piezoelectric drive device according to claim 1,
The piezoelectric driving device, wherein the piezoelectric body has a thickness of 400 nm or more and 20 μm or less. In the piezoelectric drive device according to claim 1 or 2,
The piezoelectric vibrating body includes a substrate, the first electrode formed on the substrate, the piezoelectric body formed on the first electrode, and the second electrode formed on the piezoelectric body. ,
The piezoelectric drive device, wherein the substrate is bonded to the diaphragm. The piezoelectric drive device according to claim 3.
The piezoelectric driving device, wherein the substrate is a silicon substrate. In the piezoelectric drive device according to any one of claims 1 to 4,
The diaphragm has a first surface and a second surface,
The piezoelectric vibration device is a piezoelectric driving device provided on the first surface and the second surface of the diaphragm. In the piezoelectric drive device according to any one of claims 1 to 5,
The diaphragm is a piezoelectric driving device including a protrusion that contacts a driven body. A plurality of link portions and a joint portion connecting the plurality of link portions;
The piezoelectric drive device according to any one of claims 1 to 6, wherein the plurality of link portions are rotated by the joint portions.
Robot equipped with. The robot driving method according to claim 7, wherein the piezoelectric driving device is driven by applying a periodically changing voltage between the first electrode and the second electrode of the piezoelectric driving device, A robot driving method in which the plurality of link portions are rotated by the joint portions. It is a drive method of the piezoelectric drive device according to any one of claims 1 to 6,
The voltage periodically changes between the first electrode and the second electrode, and the direction of the electric field applied to the piezoelectric body is one from the electrode toward the other electrode. A driving method of a piezoelectric driving device that applies a voltage that is a pulsating flow that is a direction.

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