Patent Application
20170092838
1. Technical Field
The present invention relates to a piezoelectric driving apparatus, method of manufacturing the same, a motor, a robot, and a pump.
2. Related Art
Ultrasonic motors for driving a driven body by vibrating a piezoelectric body are used in various fields (for example, refer to JP-A-2004-320979) since a magnet or a coil is not necessary. Such ultrasonic motors generally use piezoelectric elements (bulk piezoelectric elements) provided with a bulk-type piezoelectric body (for example, refer to JP-A-2008-227123).
On the other hand, piezoelectric elements (thin-film piezoelectric element) provided with a thin-film piezoelectric body are known. Thin-film piezoelectric elements are mainly used in the heads of ink jet printers to eject ink.
When using the thin-film piezoelectric element described above in an ultrasonic motor, there is a high possibility of being able to reduce the size of the ultrasonic motor and the device driven thereby. However, thin-film piezoelectric elements generally have a significantly smaller output than bulk piezoelectric elements. Thus, with existing thin-film piezoelectric elements, it may not be possible to obtain a sufficient output for use as the driving source of a motor for driving the joints of a robot for example.
In addition, ultrasonic motors for driving a driven body by vibrating a piezoelectric body are used in various fields since a magnet or a coil is not necessary. For example, JP-A-8-237971 and Japanese Patent No. 4813708 describe a piezoelectric driving apparatus where piezoelectric vibrating bodies are laminated in the thickness direction of the substrate.
However, in piezoelectric driving apparatuses as described above, for example, a jumper wire such as wiring is used to electrically connect a piezoelectric vibrating body, and a driving circuit or the like for driving the piezoelectric vibrating body. Therefore, space for routing the jumper wire is required in the piezoelectric driving apparatus as described above and the size of the apparatus may be increased.
An object of some aspects of the invention is to provide a piezoelectric driving apparatus which can be reduced in size. In addition, an object of some aspects of the invention is to provide a method for manufacturing a piezoelectric driving apparatus which can be reduced in size. In addition, an object of some aspects of the invention is to provide a motor, a robot, or a pump which includes the piezoelectric driving apparatus described above.
The invention can be realized in the following aspects or application examples.
One aspect of a piezoelectric driving apparatus according to the invention includes a substrate, a piezoelectric element which has a first electrode provided on the substrate, a piezoelectric body layer provided on the first electrode, and a second electrode provided on the first piezoelectric body layer, a layer including copper provided along an outer periphery of the substrate in plan view and electrically connected to the first electrode, and a conductive layer including nickel and phosphorus provided so as to cover the layer including copper.
In such a piezoelectric driving apparatus, it is possible to lower the resistance of the member which electrically connects the first electrode and a terminal of the piezoelectric driving apparatus. Due to this, it is possible to achieve a higher output in such a piezoelectric driving apparatus. Furthermore, since such a piezoelectric driving apparatus includes a piezoelectric element which is a thin-film piezoelectric element, it is possible to reduce the size thereof.
Here, in the description according to the invention, the phrase “electrically connected” is used, for example, when a “specific member” (referred to below as “A member”) is electrically connected to another specific member (referred to below as “B member”). In the description according to the invention, in a case such as in this example, the phrase “electrically connected” is used to include a case where the A member and the B member are electrically connected in direct contact and a case where the A member and the B member are electrically connected via another member.
In Application Example 1, the conductive layer may have a layer including nickel and phosphorus, and a gold layer provided so as to cover the layer including nickel and phosphorus.
In such a piezoelectric driving apparatus, in a case where the configuration of the terminal electrically connected to the piezoelectric element and the configuration of the conductive layer are the same, and the material of the external wiring connected to the terminal is metal, it is possible to bond the terminal and the external wiring using a metal bond (Au—Au bond).
In Application Example 2, the conductive layer may have a palladium layer provided between a layer including nickel and phosphorus and a gold layer.
In such a piezoelectric driving apparatus, it is possible to suppress diffusion between the layer including nickel and phosphorus and the gold layer using the palladium layer.
In any one of Application Examples 1 to 3, the conductive layer may be a non-electrolytic plating layer.
In such a piezoelectric driving apparatus, it is possible to easily form the conductive layer.
In any one of Application Examples 1 to 4, the substrate may have a first surface and a second surface on an opposite side to the first surface, the piezoelectric element may be provided on the first surface, a metal layer may be provided on the second surface, and the metal layer may be connected to the conductive layer.
In such a piezoelectric driving apparatus, it is possible to further lower the resistance of the member electrically connecting the first electrode and the terminal of the piezoelectric driving apparatus.
Application Example 5 may further include a first piezoelectric vibrating body; and a second piezoelectric vibrating body bonded to the first piezoelectric vibrating body, in which the first piezoelectric vibrating body and the second piezoelectric vibrating body may include the substrate, the piezoelectric element, and the layer including copper, and the layer including copper of the first piezoelectric vibrating body and the layer including copper of the second piezoelectric vibrating body may be bonded.
In such a piezoelectric driving apparatus, it is possible to further increase the output in comparison with a case where only one piezoelectric vibrating body is included.
In Application Example 6, the first piezoelectric vibrating body and the second piezoelectric vibrating body may form a bonded body, the bonded body may include the metal layer, a plurality of the bonded bodies may be laminated in a thickness direction of the substrate, and in adjacent bonded bodies, the metal layer of one bonded body and the metal layer of the other bonded body may be bonded.
In such a piezoelectric driving apparatus, it is possible to further increase the output in comparison with a case where only one bonded body is formed.
One aspect of a method of manufacturing a piezoelectric driving apparatus according to the invention includes forming a first electrode on a substrate; forming a piezoelectric body layer on the first electrode; forming a second electrode on the piezoelectric body layer; forming a layer including copper electrically connected to the first electrode along an outer periphery of the substrate in plan view; and forming a non-electrolytic plating layer so as to cover the layer including copper.
In the method of manufacturing a piezoelectric driving apparatus, it is possible to manufacture a piezoelectric driving apparatus which is able to increase the output. Furthermore, in the method of manufacturing a piezoelectric driving apparatus, it is possible to manufacture a piezoelectric driving apparatus which can be reduced in size.
One aspect of the piezoelectric driving apparatus according to the invention includes a first piezoelectric vibrating body having a first substrate, a first piezoelectric element provided on a first surface of the first substrate, and a first wiring layer electrically connected to the first piezoelectric element, a second piezoelectric vibrating body having a second substrate, a second piezoelectric element provided on a first surface of the second substrate, and a second wiring layer electrically connected to the second piezoelectric element, and a terminal electrically connecting external wiring and the first wiring layer and the second wiring layer, in which the first piezoelectric vibrating body and the second piezoelectric vibrating body are bonded such that the first surface of the first substrate and the first surface of the second substrate are opposed, and the terminal is connected to a side surface of the first wiring layer and a side surface of the second wiring layer, and is provided so as to protrude further outward than the side surface of the first substrate and the side surface of the second substrate.
In such a piezoelectric driving apparatus, using a flexible substrate as the external wiring makes it possible, for example, to electrically connect a driving circuit and the flexible substrate. Due to this, in such a piezoelectric driving apparatus, it is possible to reduce the size in comparison with a case of electrically connecting the driving circuit and the wiring layer using a jumper wire.
In Application Example 9, the terminal may be a non-electrolytic plating layer.
In such a piezoelectric driving apparatus, it is possible to easily form a terminal.
Application Example 9 or 10 may further include a first insulating portion provided between the first substrate and the first wiring layer; and a second insulating portion provided between the second substrate and the second wiring layer, in which the terminal may be connected to a side surface of the first insulating portion and a side surface of the second insulating portion.
In such a piezoelectric driving apparatus, it is possible to suppress contact between the terminal and the substrate. Due to this, in such a piezoelectric driving apparatus, it is possible to suppress leakage current from flowing via the terminal between the substrate of the first piezoelectric vibrating body and the substrate of the second piezoelectric vibrating body.
In any one of Application Example 9 to 11, the terminal may be provided to be separated from the first substrate and the second substrate.
In such a piezoelectric driving apparatus, it is possible to suppress leakage current from flowing via the terminal between the substrate of the first piezoelectric vibrating body and the substrate of the second piezoelectric vibrating body.
One aspect of a method of manufacturing a piezoelectric driving apparatus according to the invention includes forming a first piezoelectric vibrating body having a first substrate, a first piezoelectric element provided on a first surface of the first substrate, and a first wiring layer electrically connected to the first piezoelectric element, forming a second piezoelectric vibrating body having a second substrate, a second piezoelectric element provided on a first surface of the second substrate, and a second wiring layer electrically connected to the second piezoelectric element, and bonding the first piezoelectric vibrating body and the second piezoelectric vibrating body such that the first surface of the first substrate and the first surface of the second substrate are opposed, and forming a terminal so as to be connected to a side surface of the first wiring layer and a side surface of the second wiring layer, and protrude further outward than the side surface of the first substrate and the side surface of the second substrate.
In the method of manufacturing a piezoelectric driving apparatus, it is possible to manufacture a piezoelectric driving apparatus which can be reduced in size.
In Application Example 13, the terminal may be formed by non-electrolytic plating in the forming of the terminal.
In the method of manufacturing a piezoelectric driving apparatus, it is possible to easily form a terminal.
In Application Example 13 or 14, in the forming of the first piezoelectric vibrating body, the first piezoelectric vibrating body may be formed so as to have a first insulating portion, in the forming of the second piezoelectric vibrating body, the second piezoelectric vibrating body may be formed so as to have a second insulating portion, and, in the forming of the terminal, the terminal may be formed so as to connect a side surface of the first insulating portion and a side surface of the second insulating portion.
In the method of manufacturing a piezoelectric driving apparatus, it is possible to manufacture a piezoelectric driving apparatus which can suppress leakage current from flowing via the terminal between the substrate of the first piezoelectric vibrating body and the substrate of the second piezoelectric vibrating body.
In any one of Application Examples 13 to 15, in the forming of the terminal, the terminal may be formed so as to be separated from the first substrate and the second substrate.
In the method of manufacturing a piezoelectric driving apparatus, it is possible to manufacture a piezoelectric driving apparatus which can suppress leakage current from flowing via the terminal between the substrate of the first piezoelectric vibrating body and the substrate of the second piezoelectric vibrating body.
One aspect of the piezoelectric driving apparatus according to the invention includes a plurality of vibrating units, in which the vibrating units include a vibrating plate having a fixing portion, a vibrating portion, and a connecting portion connecting the fixing portion and the vibrating portion, a first electrode provided above the vibrating portion, a first piezoelectric body layer provided above the first electrode, a second electrode provided above the first piezoelectric body layer, a third electrode provided above the fixing portion, a second piezoelectric body layer provided above the third electrode, and a fourth electrode provided above the second piezoelectric body layer, the first electrode, the first piezoelectric body layer, and the second electrode form a piezoelectric element, and the vibrating unit is disposed so as to overlap a plate surface of the vibrating plate in an orthogonal direction.
In such a piezoelectric driving apparatus, a structure similar to the piezoelectric element is formed in the fixing portion of the vibrating plate and, due to this, when the plurality of vibrating units are overlapped, a bending force is not easily generated in the thickness direction thereof and the plurality of vibrating units are laminated in a favorable flat state and damage or the like does not occur easily. Due to this, the residual stress in the vibrating unit is small and damage or the like does not occur easily, in addition, it is possible to easily carry out the manufacturing since the first piezoelectric body layer and the second piezoelectric body layer can be formed in the same step.
In Application Example 17, the vibrating unit may include an insulating layer provided above the second electrode and the fourth electrode and a wiring layer provided above the insulating layer, and at least one of the second electrode and the fourth electrode may be electrically connected to the wiring layer.
In such a piezoelectric driving apparatus, even in a case where the electrodes are formed of thin films, it is possible to reduce the wiring resistance and to carry out the driving efficiently.
In Application Example 18, an inductor may be formed by electrically connecting the wiring layers of the adjacently disposed vibrating units to each other.
According to such a piezoelectric driving apparatus, it is possible to save space for installing the inductor. Therefore, it is possible to increase the space utilization efficiency in comparison with a case of providing an inductor externally.
In any one of Application Examples 17 to 19, the third electrode, the second piezoelectric body layer, and the fourth electrode may form a capacitor.
According to such a piezoelectric driving apparatus, it is possible to save space for installing the capacitor. Therefore, it is possible to increase the space utilization efficiency in comparison with a case of providing a capacitor externally. Furthermore, in a case where the second piezoelectric body layer which forms the capacitor is the same material as the first piezoelectric body layer which forms the piezoelectric element, since the temperature characteristics of the capacitor and the temperature characteristics of the piezoelectric element are similar and both are disposed at spatially close positions, for example, it is possible to simplify the driving circuit or control for responding to changes in temperature.
In Application Example 20, the capacitor may be electrically connected in parallel with the piezoelectric element as seen from a power source of the vibrating unit.
According to such a piezoelectric driving apparatus, it is possible to increase the apparent impedance in a case of being viewed as an electrical element and to further increase the mechanical output in a case of being viewed as an acoustic element.
In any one of Application Example 17 to 21, the wiring layer may form an inductor.
In such a piezoelectric driving apparatus, it is possible to save space for installing the inductor. Therefore, it is possible to increase the space utilization efficiency in comparison with a case of providing an inductor externally.
In Application Example 22, the inductor may be electrically connected in parallel with the piezoelectric element as seen from the power source of the vibrating unit.
According to such a piezoelectric driving apparatus, it is possible to increase the apparent impedance in a case of being viewed as an electrical element and to further increase the mechanical output in a case of being viewed as an acoustic element.
One aspect of a motor according to the invention includes the piezoelectric driving apparatus according to any one of Application Examples 1 to 7, 9 to 12, and 17 to 23; and a rotor rotated by the piezoelectric driving apparatus.
In such a motor, it is possible to include the piezoelectric driving apparatus according to an aspect of the invention.
One aspect of a robot according to the invention includes a plurality of link portions; joint portions connecting the plurality of link portions; and the piezoelectric driving apparatus according to any one of Application Examples 1 to 7, 9 to 12, and 17 to 23, which rotates the plurality of link portions in the joint portions.
In such a robot, it is possible to include the piezoelectric driving apparatus according to an aspect of the invention.
One aspect of a pump according to the invention includes the piezoelectric driving apparatus according to any one of Application Examples 1 to 7, 9 to 12, and 17 to 23; a tube transporting a liquid; and a plurality of fingers closing the tube according to driving of the piezoelectric driving apparatus.
In such a pump, it is possible to include the piezoelectric driving apparatus according to an aspect of the invention.
Here, in the present specification, when referring to arranging (or forming) a specific member Y above (or below) a specific member X, the aspect is not limited to an aspect where the member Y is disposed (or formed) in direct contact above (or below) the member X, but includes an aspect where the member Y is disposed (or formed) via another member above (or below) the member X in a range in which the operation and effects thereof are not inhibited.
The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
Detailed description will be given of favorable embodiments of the invention using the diagrams. Here, the embodiments described below do not unduly limit the contents of the invention described in the claims. In addition, it is not necessarily the case that all of the configurations described below are constituent elements of the invention.
First, description will be given of the piezoelectric driving apparatus according to the first embodiment with reference to the drawings.
As shown in
Here,
As shown in
As shown in
As shown in
The contact portion 20 is provided on the vibrating body portion 12. In the illustrated example, a concave portion 12a is provided in the vibrating body portion 12 and the contact portion 20 is fitted into and bonded to (for example, adhered to) the concave portion 12a. The contact portion 20 is a member which comes in contact with a driven member to transmit the movement of the vibrating body portion 12 to the driven member. The material of the contact portion 20 is, for example, a ceramic (specifically, alumina (Al2O3)), zirconia (ZrO2), silicon nitride (Si3N), or the like).
The piezoelectric element 30 is provided on the substrate 10. Specifically, the piezoelectric element 30 is provided on the vibrating body portion 12. The piezoelectric element 30 has a first electrode 32, a piezoelectric body layer 34, and a second electrode 36.
The first electrode 32 is provided on the vibrating body portion 12. In the illustrated example, the planar shape of the first electrode 32 is a rectangle. The first electrode 32 may be formed by an iridium layer provided on the vibrating body portion 12 and a platinum layer provided on the iridium layer. The thickness of the iridium layer is, for example, 5 nm to 100 nm. The thickness of the platinum layer is, for example, 50 nm to 300 nm. Here, the first electrode 32 may be a metal layer formed of Ti, Pt, Ta, Ir, Sr, In, Sn, Au, Al, Fe, Cr, Ni, Cu, and the like or a mixture or a laminate of two or more types thereof. The first electrode 32 is one electrode for applying a voltage to the piezoelectric body layer 34.
The piezoelectric body layer 34 is provided on the first electrode 32. In the illustrated example, the planar shape of the piezoelectric body layer 34 is a rectangle. The thickness of the piezoelectric body layer 34 is, for example, 50 nm to 20 μm, preferably 1 μm to 7 μm. In this manner, the piezoelectric element 30 is a thin-film piezoelectric element. When the thickness of the piezoelectric body layer 34 is less than 50 nm, the output of the piezoelectric driving apparatus 100 may be reduced. Specifically, when attempting to increase the output and increase the applied voltage to the piezoelectric body layer 34, the piezoelectric body layer 34 may cause dielectric breakdown. When the thickness of the piezoelectric body layer 34 is greater than 20 μm, cracks may occur in the piezoelectric body layer 34.
As the piezoelectric body layer 34, a perovskite-type oxide piezoelectric material is used. Specifically, the material of the piezoelectric body layer 34 is, for example, lead zirconate titanate (Pb(Zr,Ti)O3: PZT), or lead zirconate titanate niobate (Pb(Zr,Ti,Nb)O3: PZTN). It is possible to change the shape of (expand and contract) the piezoelectric body layer 34 by applying a voltage using the electrodes 32 and 36.
The second electrode 36 is provided on the piezoelectric body layer 34. In the illustrated example, the planar shape of the second electrode 36 is a rectangle. The second electrode 36 may be formed of the adhesive layer provided on the piezoelectric body layer 34, and a conductive layer provided on the adhesive layer. The thickness of the adhesive layer is, for example, 10 nm to 100 nm. The adhesive layer is, for example, a TiW layer, a Ti layer, a Cr layer, a NiCr layer, or a laminate thereof. The thickness of the conductive layer is, for example, 1 μm to 10 μm. The conductive layer is, for example, a Cu layer, an Au layer, an Al layer, or a laminate thereof. The second electrode 36 is the other electrode for applying a voltage to the piezoelectric body layer 34.
As shown in
As shown in
The first wiring layer 50 is provided on the second electrode 36. The first wiring layer 50 is electrically connected to the second electrode 36. In the illustrated example, the first wiring layer 50 is provided on the first insulating layer 40 and in a contact hole 40a formed in the first insulating layer 40 to be connected to the second electrode 36.
The first wiring layer 50 is a layer including copper. The first wiring layer 50 may be formed of a titanium tungsten layer, and a copper layer provided on the titanium tungsten layer. In the illustrated example, the first wiring layer 50 is covered with a non-electrolytic plating layer 51 formed by non-electrolytic plating. The non-electrolytic plating layer 51 may be formed of a layer (Ni—P layer) including nickel and phosphorus. Alternatively, the non-electrolytic plating layer 51 may be formed of a Ni—P layer, and a gold layer provided on the Ni—P layer. Alternatively, the non-electrolytic plating layer 51 may be formed of a Ni—P layer, a palladium layer provided on the Ni—P layer, and a gold layer provided on the palladium layer.
The second insulating layer 42 is provided so as to cover the first wiring layer 50. In the illustrated example, the second insulating layer 42 is provided so as to cover the first wiring layer 50 via the non-electrolytic plating layer 51. The material of the second insulating layer 42 is, for example, the same as the material of the first insulating layer 40.
The second wiring layer 52 has a first portion 52a which is electrically connected to the first electrode 32, and a second portion 52b which is electrically connected to the second electrode 36. As shown in
The first portion 52a of the second wiring layer 52 is connected to the first electrode 32. In the example shown in
As shown in
As shown in
As shown in
Here, the second wiring layer 52 of the first piezoelectric vibrating body 101 and the second wiring layer of the second piezoelectric vibrating body 102 may be bonded by metallic bonds (Cu—Cu bond). Due to this, the piezoelectric vibrating bodies 101 and 102 can be strongly bonded to without using an adhesive.
As shown in
The conductive layer 60 is provided so as to cover the end portion of the second wiring layer 52. In the illustrated example, the conductive layer 60 is provided to the side of the first portion 52a of the second wiring layer of the piezoelectric vibrating bodies 101 and 102 and connected to the first portion 52a. In other words, the conductive layer 60 is provided above a portion where the second wiring layer 52 is exposed in the side portion when the first piezoelectric vibrating body 101 and the second piezoelectric vibrating body 102 are bonded.
The conductive layer 60 is a non-electrolytic plating layer formed by non-electrolytic plating. The conductive layer 60 has, for example, a layer (Ni—P layer) including nickel and phosphorus, a palladium layer 64, and a gold layer 66. The Ni—P layer 62 is provided so as to cover the first portion 52a. The palladium layer 64 is provided so as to cover the Ni—P layer 62. The palladium layer 64 is provided between the Ni—P layer 62 and the gold layer 66. The gold layer 66 is provided so as to cover the Ni—P layer 62 via the palladium layer 64. Here, although not shown, the palladium layer 64 may not be provided. In addition, the palladium layer 64 and the gold layer 66 may not be provided.
The metal layer 70 is provided on the second surface 10b and the third surface 10c of the substrate 10. The metal layer 70 is connected to the conductive layer 60. In the illustrated example, the metal layer 70 is connected to the gold layer 66 of the conductive layer 60. The metal layer 70 is, for example, a copper layer.
The terminal 80 is, for example, electrically connected to the first electrode 32 common to the piezoelectric elements 30a, 30b, 30c, 30d, and 30e via the first portion 52a (refer to
The terminal 80 is, for example, connected to the metal layer 70. Here, although not shown, the terminals 82, 84, and 86 are not connected to the metal layer 70. In addition, the terminal 80 may also not be connected to the metal layer 70.
As shown in
Here, the materials of the first conductive layer 33, the insulating layer 35, and the second conductive layer 37 are respectively the same as the materials of the first electrode 32, the piezoelectric body layer 34, and the second electrode 36. The first conductive layer 33, the insulating layer 35, and the second conductive layer 37 can each be formed in the step of forming the first electrode 32, the piezoelectric body layer 34, and the second electrode 36. No voltage is applied to the piezoelectric body layer 34 due to the conductive layers 33 and 37. In the example shown in
The driving circuit 110 applies a periodically changing AC voltage or a pulsating voltage between the first electrode 32 and the second electrode 36 of predetermined piezoelectric elements out of the five piezoelectric elements 30a, 30b, 30c, 30d, and 30e, for example, the piezoelectric elements 30a, 30d, and 30e. Due to this, the piezoelectric driving apparatus 100 is able to rotate the rotor (driven member) in contact with the contact portion 20 in a predetermined rotation direction by ultrasonically vibrating the vibrating body portion 12. Here, the “pulsating voltage” has the meaning of a voltage where a DC offset is applied to an AC voltage and the orientation of the voltage (electric field) of the pulsating voltage is a direction from one electrode to the other electrode.
Here, the orientation of the current is more preferably from the second electrode 36 toward the first electrode 32 than from the first electrode 32 toward the second electrode 36. In addition, applying the AC voltage or the pulsating voltage between the electrodes 32 and 36 of the piezoelectric elements 30b, 30c, and 30e makes it possible to rotate the rotor in contact with the contact portion 20 in the opposite direction.
As shown in
Here, in the same manner as the terminal 80, the terminals 82, 84, and 86 are electrically connected to the driving circuit 110 via the flexible substrate 120. In addition, although not shown in the diagram, the terminals 80, 82, 84, and 86 and the driving circuit 110 may be electrically connected using wiring or solder.
Here, in a case where the driving circuit 110 applies an AC voltage or a pulsating voltage between the electrodes 32 and 36 of the piezoelectric elements 30b, 30c, and 30e, the rotor 4 rotates in the opposite direction to the direction R (the counterclockwise direction).
In addition, the resonance frequency of the bending vibration and the resonance frequency of the longitudinal vibration of the vibrating body portion 12 are preferably the same. Due to this, the piezoelectric driving apparatus 100 can efficiently rotate the rotor 4.
As shown in
The piezoelectric driving apparatus 100, for example, has the following characteristics.
The piezoelectric driving apparatus 100 includes the second wiring layer 52 electrically connected to the first electrode 32 and the conductive layer 60 provided so as to cover the second wiring layer 52, provided along the outer periphery of the substrate 10 in plan view. Therefore, in the piezoelectric driving apparatus 100, it is possible to lower the resistance of the member which electrically connects the first electrode 32 and the terminal 80. Due to this, in the piezoelectric driving apparatus 100, it is possible to improve the efficiency of the voltage applied to the piezoelectric body layer 34, furthermore, it is possible to reduce the amount of heating of the member which electrically connects the first electrode 32 and the terminal 80. Furthermore, since the thin-film piezoelectric element has a larger capacitance than a bulk piezoelectric element, the impedance of the piezoelectric body layer is reduced. In the piezoelectric driving apparatus 100, lowering the resistance of the member which electrically connects the first electrode 32 and the terminal 80 makes it possible to increase the impedance of the piezoelectric body layer 34, and to increase the voltage applied to the piezoelectric body layer 34. As a result, the piezoelectric driving apparatus 100 can achieve a higher output.
Furthermore, since the piezoelectric driving apparatus 100 includes the piezoelectric element 30 which is a thin-film piezoelectric element, it is possible to reduce the size thereof in comparison with a case of including a bulk piezoelectric element.
Here, the heat treatment is performed in an oxygen atmosphere in order to form the piezoelectric body layer 34 and is performed at 700° C. to 800° C. Therefore, the first electrode 32 is formed of a material which can withstand high temperatures and which includes platinum which is not oxidized. Accordingly, when the resistance of the first electrode is lowered and the output of the piezoelectric driving apparatus is increased by increasing the thickness of the first electrode, the costs are increased. In the piezoelectric driving apparatus 100 according to the present embodiment, it is possible to achieve a higher output while reducing costs.
In the piezoelectric driving apparatus 100, the conductive layer 60 has the gold layer 66 provided so as to cover the Ni—P layer 62. Therefore, in a case where the configuration of the terminals 80, 82, 84, and 86 and the configuration of the conductive layer 60 are the same and the material of the outer external wiring (specifically, the wiring layer 124 of the flexible substrate 120) connected to the terminals 80, 82, 84, and 86 is gold, it is possible to bond the terminals 80, 82, 84, and 86 and the external wiring using a metal bond (an Au—Au bond).
In the piezoelectric driving apparatus 100, the conductive layer 60 has the palladium layer 64 provided between the Ni—P layer 62 and the gold layer 66. Therefore, in the piezoelectric driving apparatus 100, it is possible to suppress diffusion between the Ni—P layer 62 and the gold layer 66 due to the palladium layer 64.
In the piezoelectric driving apparatus 100, the conductive layer 60 is a non-electrolytic plating layer. Therefore, in the piezoelectric driving apparatus 100, for example, selectively attaching palladium as catalyst to the first portion 52a surface of the second wiring layer 52 makes it possible to selectively form the conductive layer 60. Due to this, in the piezoelectric driving apparatus 100, for example, even in a case where the substrate 10 is in a wafer state, it is possible to easily form the conductive layer 60. In addition, even when the distance between the substrate 10 of the first piezoelectric vibrating body 101 and the substrate 10 of the second piezoelectric vibrating body 102 is reduced to approximately 20 μm, it is possible to easily form the conductive layer 60. For example, in a case where the conductive layer 60 is formed by a sputtering method, it is necessary to perform sputtering from a direction perpendicular to the thickness direction of the substrate 10 and it may not be possible to easily form the conductive layer 60.
Furthermore, the non-electrolytic plating layer can be formed simply by immersion in liquid. Therefore, in the piezoelectric driving apparatus 100, forming the conductive layer 60 makes it possible to suppress damage to the second wiring layer 52. In addition, in the piezoelectric driving apparatus 100, for example, it is possible to form the conductive layer 60 at low cost.
In the piezoelectric driving apparatus 100, the metal layer 70 is provided on the second surface 10b of the substrate 10, and the metal layer 70 is connected to the conductive layer 60. Therefore, in the piezoelectric driving apparatus 100, the resistance of the member which electrically connects the first electrode 32 and the terminal 80 can be further decreased.
The piezoelectric driving apparatus 100 includes the first piezoelectric vibrating body 101 and the second piezoelectric vibrating body 102 which is bonded to the first piezoelectric vibrating body 101. Therefore, in the piezoelectric driving apparatus 100, it is possible to achieve a higher output in comparison with a case where only one piezoelectric vibrating body is included.
The piezoelectric driving apparatus 100 includes the non-electrolytic plating layer 51 provided so as to cover the first wiring layer 50. Therefore, in the piezoelectric driving apparatus 100, for example, when forming the second insulating layer 42, it is possible to suppress the first wiring layer 50 from being oxidized. Specifically, in a case where the material of the second insulating layer 42 is an organic material, a heat treatment (baking) is performed at the time of forming the second insulating layer 42; however, since the first wiring layer includes copper, the first wiring layer 50 is easily oxidized by the heat treatment. However, in the piezoelectric driving apparatus 100, since the non-electrolytic plating layer 51 is provided so as to cover the first wiring layer 50, it is possible to suppress the oxidation of the first wiring layer 50 due to the non-electrolytic plating layer 51.
The motor 130 includes the piezoelectric driving apparatus 100. Therefore, the motor 130 can achieve an increased output and a reduction in size.
Next, description will be given of a method of manufacturing a piezoelectric driving apparatus 100 according to the first embodiment with reference to the drawings.
The first piezoelectric vibrating body 101 and the second piezoelectric vibrating body 102 are basically formed by the same manufacturing method. Accordingly, description will be given below of the method of manufacturing the first piezoelectric vibrating body 101 using
As shown in
Here, the substrate 10 may be in a wafer state. That is, although not shown, a frame portion is provided on the periphery of the substrate 10 and the substrate 10 may be connected to the frame portion via a cut-away portion. In such a case, the substrate 10, the frame portion, and the cut-away portion are integrally provided.
Next, the piezoelectric body layer 34 is formed on the first electrode 32 (S2). The piezoelectric body layer 34 is, for example, formed by patterning after repeating the forming of the precursor layer by a liquid phase method and the crystallization of the precursor layer. The liquid phase method is a method of forming a film with a thin-film material using a raw material solution which includes a constituent material of the thin film (piezoelectric body layer), specifically, a sol-gel method, a metal organic deposition (MOD) method, or the like. The crystallization is performed by a heat treatment at 700° C. to 800° C. in an oxygen atmosphere. In this step, it is possible to form the insulating layer 35 on the first conductive layer 33 (refer to
Next, the second electrode 36 is formed on the piezoelectric body layer 34 (S3). The second electrode 36 is, for example, formed with the same method as the first electrode 32. Although not shown, the patterning of the second electrode 36 and the patterning of the piezoelectric body layer 34 may be performed as the same step. In this step, it is possible to form the second conductive layer 37 on the insulating layer 35 (refer to
Through the above steps, it is possible to form the piezoelectric element 30 on the vibrating body portion 12 of the substrate 10.
As shown in
Next, the first wiring layer 50 is formed on the second electrode 36 and on the first insulating layer 40 (S5). The first wiring layer 50 is formed by, for example, a plating (electroplating) method, film-forming by sputtering and patterning, or the like.
Next, the non-electrolytic plating layer 51 is formed so as to cover the first wiring layer 50 (S6). The non-electrolytic plating layer 51 is formed by non-electrolytic plating. Specifically, after selectively attaching palladium as a catalyst to the surface of the first wiring layer 50, the non-electrolytic plating layer 51 is selectively formed on the surface of the first wiring layer 50 by non-electrolytic plating.
As shown in
Next, the second wiring layer 52 is formed on the electrodes 32 and 36 and the second insulating layer 42 (S8). The second wiring layer 52 is, for example, formed in the same manner as the first wiring layer 50. Specifically, the first portion 52a of the second wiring layer 52 electrically connected to the first electrode 32 is formed along the outer periphery of the substrate 10 in plan view. Furthermore, the second portion 52b of the second wiring layer 52 electrically connected to the second electrode 36 is formed.
Through the above steps, it is possible to form the first piezoelectric vibrating body 101 and the second piezoelectric vibrating body 102. Here, in a case where the substrate 10 is in a wafer state, the first piezoelectric vibrating body 101 and the second piezoelectric vibrating body 102 may be formed on different wafers.
As shown in
As shown in
As shown in
Next, the metal layer 70 is formed on the surfaces 10b and 10c of the substrate 10 (S12). The metal layer 70 is formed so as to be connected to the conductive layer 60. The metal layer 70 is, for example, formed by a sputtering method.
Here, although not shown, in a case where the substrate 10 is a wafer state, after step (S12), a cut-away portion is cut away by etching or the like to separate the substrate 10 from the frame portion (chip forming).
Through the above steps, it is possible to manufacture the piezoelectric driving apparatus 100.
The manufacturing method of the piezoelectric driving apparatus 100 includes a step (S8) of forming the second wiring layer 52 electrically connected to the first electrode 32 along the outer periphery of the substrate 10 in plan view, and a step (S11) of forming the conductive layer 60 which is a non-electrolytic plating layer so as to cover the layer which includes the second wiring layer. Therefore, in the manufacturing method of the piezoelectric driving apparatus 100, it is possible to manufacture the piezoelectric driving apparatus 100 which can achieve a high output.
Furthermore, in the manufacturing method of the piezoelectric driving apparatus 100, including a step (S1) of forming the first electrode 32 on the substrate 10, a step (S2) of forming the piezoelectric body layer 34 on the first electrode 32, and a step (S3) of forming the second electrode 36 on the piezoelectric body layer 34 makes it possible to form the piezoelectric element 30 which is a thin-film piezoelectric element. Therefore, in the manufacturing method of the piezoelectric driving apparatus 100, it is possible to manufacture the piezoelectric driving apparatus 100 which can be miniaturized in comparison with a case of including the bulk piezoelectric element.
Next, description will be given of the piezoelectric driving apparatus according to a modification example of the first embodiment with reference to the drawings.
Below, in the piezoelectric driving apparatus 200 according to the modification example of the first embodiment, the constituent members of the piezoelectric driving apparatus 100 of the first embodiment and the members having the same functions are given the same reference numerals and the details thereof will be omitted.
As shown in
In the piezoelectric driving apparatus 200, the first piezoelectric vibrating body 101 and the second piezoelectric vibrating body 102 form a bonded body 210. The bonded body 210 has the metal layer 70. A plurality of the bonded bodies 210 are provided. In the illustrated example, three of the bonded body 210 are provided. A plurality of the bonded bodies 210 are laminated in the thickness direction of the substrate 10.
In the adjacent bonded bodies 210, the metal layer 70 of one of the bonded bodies 210 and the metal layer 70 of the other bonded body 210 are bonded. For example, in a case where the metal layers 70 are gold layers, the metal layer 70 of one of the bonded bodies 210 and the metal layer 70 of the other bonded body 210 are bonded by metal bonding (Au—Au bond). Due to this, it is possible to strongly bond the adjacent bonded bodies 210 without using an adhesive. Here, although not shown, the metal layer 70 of one of the bonded bodies 210 and the metal layer 70 of the other bonded body 210 may be bonded by a conductive adhesive.
In the piezoelectric driving apparatus 200, a plurality of bonded bodies 210 are laminated in the thickness direction of the substrate 10. Therefore, in the piezoelectric driving apparatus 200, it is possible to increase the output in comparison with a case where only one bonded body 210 is formed.
Next, description will be given of a piezoelectric driving apparatus according to a second embodiment with reference to the drawings.
As shown in
Here,
As shown in
As shown in
The substrate 10 is, for example, formed of a silicon substrate 11a and an underlayer 11b provided on the silicon substrate 11a. The underlayer 11b is an insulating layer. The underlayer 11b is, for example, formed of a laminated body of a silicon oxide layer provided on the silicon substrate 11a, and a zirconium oxide layer provided on the silicon oxide layer.
As shown in
The contact portion 20 is provided on the vibrating body portion 12. In the illustrated example, the concave portion 12a is provided in the vibrating body portion 12 and the contact portion 20 is fitted into and bonded to (for example, adhered to) the concave portion 12a. The contact portion 20 is a member which comes in contact with a driven member to transmit the movement of the vibrating body portion 12 to the driven member. The material of the contact portion 20 is, for example, a ceramic (specifically, alumina (Al2O3)), zirconia (ZrO2), silicon nitride (Si3N), or the like).
The piezoelectric element 30 is provided on the substrate 10. The piezoelectric element 30 is provided on the first surface 10a of the substrate 10. The piezoelectric element 30 is provided on the vibrating body portion 12. The piezoelectric element 30 has the first electrode 32, the piezoelectric body layer 34, and the second electrode 36.
The first electrode 32 is provided on the vibrating body portion 12. In the illustrated example, the planar shape of the first electrode 32 is a rectangle. The first electrode 32 may be formed by an iridium layer provided on the vibrating body portion 12 and a platinum layer provided on the iridium layer. The thickness of the iridium layer is, for example, 5 nm to 100 nm. The thickness of the platinum layer is, for example, 50 nm to 300 nm. Here, the first electrode 32 may be a metal layer formed of Ti, Pt, Ta, Ir, Sr, In, Sn, Au, Al, Fe, Cr, Ni, Cu, and the like or a mixture or a laminate of two or more types thereof. The first electrode 32 is one electrode for applying a voltage to the piezoelectric body layer 34.
The piezoelectric body layer 34 is provided on the first electrode 32. In the illustrated example, the planar shape of the piezoelectric body layer 34 is a rectangle. The thickness of the piezoelectric body layer 34 is, for example, 50 nm to 20 μm, preferably 1 μm to 7 μm. In this manner, the piezoelectric element 30 is a thin-film piezoelectric element. When the thickness of the piezoelectric body layer 34 is less than 50 nm, the output of the piezoelectric driving apparatus 300 may be reduced. Specifically, when attempting to increase the output and increase the applied voltage to the piezoelectric body layer 34, the piezoelectric body layer 34 may cause dielectric breakdown. When the thickness of the piezoelectric body layer 34 is greater than 20 μm, cracks may occur in the piezoelectric body layer 34.
As the piezoelectric body layer 34, a perovskite-type oxide piezoelectric material is used. Specifically, the material of the piezoelectric body layer 34 is, for example, lead zirconate titanate (Pb(Zr,Ti)O3: PZT), or lead zirconate titanate niobate (Pb(Zr,Ti,Nb)O3: PZTN). It is possible to change the shape of (expand and contract) the piezoelectric body layer 34 by applying a voltage using the electrodes 32 and 36.
The second electrode 36 is provided on the piezoelectric body layer 34. In the illustrated example, the planar shape of the second electrode 36 is a rectangle. The second electrode 36 may be formed of the adhesive layer provided on the piezoelectric body layer 34, and a conductive layer provided on the adhesive layer. The thickness of the adhesive layer is, for example, 10 nm to 100 nm. The adhesive layer is, for example, a TiW layer, a Ti layer, a Cr layer, a NiCr layer, or a laminate thereof. The thickness of the conductive layer is, for example, 1 μm to 10 μm. The conductive layer is, for example, a Cu layer, an Au layer, an Al layer, or a laminate thereof. The second electrode 36 is the other electrode for applying a voltage to the piezoelectric body layer 34.
As shown in
As shown in
The wiring layer 350 is provided on the second electrode 36. The wiring layer 350 is electrically connected to the second electrode 36. In the illustrated example, the wiring layer 350 is provided on the insulating layer 340 and a contact hole 340b formed in the insulating layer 340, and is connected to the second electrode 36.
The wiring layer 350 is a layer including copper. The wiring layer 350 may be formed of a titanium tungsten layer, and a copper layer provided on the titanium tungsten layer. In the illustrated example, the wiring layer 350 is covered with a non-electrolytic plating layer 351 which is formed by non-electrolytic plating. The non-electrolytic plating layer 351 may be formed of a layer (Ni—P layer) including nickel and phosphorus. Alternatively, the non-electrolytic plating layer 351 may be formed of a Ni—P layer, and a gold layer provided on the Ni—P layer. Alternatively, the non-electrolytic plating layer 351 may be formed of a Ni—P layer, a palladium layer provided on the Ni—P layer, and a gold layer provided on the palladium layer.
The insulating layer 342 is provided so as to cover the wiring layer 350. In the illustrated example, the insulating layer 342 is provided so as to cover the wiring layer 350 via the non-electrolytic plating layer 351. The material of the insulating layer 342 may be an inorganic material such as silicon oxide or aluminum oxide, or may be an organic material such as an epoxy-based resin, an acrylic-based resin, a polyimide-based resin, or a silicone-based resin. The material of the insulating layer 342 may be a photosensitive material.
The insulating layer 343 is provided on the insulating layer 342. The insulating layer 343 has, for example, the role of a wall for forming the wiring layer 352 on the insulating layer 342. The material of the insulating layer 343 may be an inorganic material such as silicon oxide or aluminum oxide, or may be an organic material such as an epoxy-based resin, an acrylic-based resin, a polyimide-based resin, or a silicone-based resin. The material of the insulating layer 343 may be a photosensitive material.
The wiring layer 352 is provided on the non-electrolytic plating layer 351. In the example shown in
As shown in
Here, the wiring layer 352 of the first piezoelectric vibrating body 101 and the wiring layer 352 of the second piezoelectric vibrating body 102 may be bonded by a metal bond (Cu—Cu bond or Au—Au bond). Due to this, the piezoelectric vibrating bodies 101 and 102 can be strongly bonded to without using an adhesive.
Here, the substrate 10 of the first piezoelectric vibrating body 101 is the first substrate. The piezoelectric element 30 of the first piezoelectric vibrating body 101 is the first piezoelectric element. The wiring layer 352 of the first piezoelectric vibrating body 101 is the first wiring layer. The insulating layers 340 and 342 of the first piezoelectric vibrating body 101 form a first insulating portion 344. The first insulating portion 344 is provided between the first substrate and the first wiring layer.
In addition, the substrate 10 of the second piezoelectric vibrating body 102 is the second substrate. The piezoelectric element 30 of the second piezoelectric vibrating body 102 and the wiring layer 352 of the second piezoelectric vibrating body 102 which is the second piezoelectric element are the second wiring layer. The insulating layers 340 and 342 of the second piezoelectric vibrating body 102 form a second insulating portion 346. The second insulating portion 346 is provided between the second substrate and the second wiring layer.
As shown in
The terminals 80, 82, 84, and 86 are non-electrolytic plating layers formed by non-electrolytic plating. The terminals 80 to 86 may be formed of a layer (Ni—P layer) including nickel and phosphorus. Alternatively, the terminals 80 to 86 may be formed of a Ni—P layer, and a gold layer provided so as to cover the Ni—P layer. Alternatively, the terminals 80 to 86 may be formed of a Ni—P layer, a palladium layer provided so as to cover the Ni—P layer, and a gold layer provided so as to cover the palladium layer.
Here, as shown in
The terminal 80 is, for example, electrically connected to the second electrodes 36 of the piezoelectric elements 30a and 30d via the first portion 353a of the wiring layer 352. The terminal 82 is, for example, electrically connected to the second electrode 36 of the piezoelectric element 30e via the second portion 353b of the wiring layer 352. The terminal 84 is, for example, electrically connected to the second electrodes 36 of the piezoelectric elements 30b and 30c via the third portion 353c of the wiring layer 352. The terminal 86 is, for example, electrically connected to the first electrode 32 of the piezoelectric elements 30a, 30b, 30c, and 30d, and 30e via the fourth portion 353d of the wiring layer 352. The terminal 86 may have a reference potential as a ground. In the piezoelectric driving apparatus 300, connecting the terminals 80 to 86 and the driving circuit makes it possible to apply a voltage to the piezoelectric body layer 34 of the piezoelectric elements 30a to 30e and to vibrate the vibrating body portion 12.
As shown in
Here, the materials of the first conductive layer 33, the insulating layer 35, and the second conductive layer 37 are respectively the same as the materials of the first electrode 32, the piezoelectric body layer 34, and the second electrode 36. The first conductive layer 33, the insulating layer 35, and the second conductive layer 37 can each be formed in the step of forming the first electrode 32, the piezoelectric body layer 34, and the second electrode 36. No voltage is applied to the piezoelectric body layer 34 due to the conductive layers 33 and 37. For example, the first conductive layer 33 is electrically separated from the first electrode 32 and the second conductive layer 37 is electrically separated from the second electrode 36. In the examples shown in
As shown in
As shown in
The piezoelectric driving apparatus 300 has, for example, the following characteristics.
In the piezoelectric driving apparatus 300, the terminals 80, 82, 84, and 86 are connected to the side surface 352a of the wiring layer 352 of the piezoelectric vibrating bodies 101 and 102 and provided so as to protrude outward further than the side surface 10c of the substrate of the piezoelectric vibrating bodies 101 and 102. Therefore, in the piezoelectric driving apparatus 300, the driving circuit 110 and the wiring layer 352 can, for example, be electrically connected by using the flexible substrate 120 as external wiring. Due to this, in the piezoelectric driving apparatus 300, it is possible to reduce the size in comparison with a case where the driving circuit 110 and the wiring layer 352 are electrically connected using a jumper wire. Furthermore, in the piezoelectric driving apparatus 300, the routing of the external wiring can be simplified, and it is possible to easily electrically connect the driving circuit 110 and the wiring layer 352. For example, in a case where the driving circuit 110 and the wiring layer 352 are electrically connected using a jumper wire, in a case where a plurality of piezoelectric vibrating bodies are laminated, space for routing the jumper wire is necessary and the apparatus may increase in size.
In the piezoelectric driving apparatus 300, the terminals 80, 82, 84, and 86 are non-electrolytic plating layers. Therefore, in the piezoelectric driving apparatus 300, for example, it is possible to selectively form the terminals 80 to 86 by selectively attaching palladium as a catalyst to the side surface 352a of the wiring layer 352. Due to this, in the piezoelectric driving apparatus 300, for example, it is possible to easily form the terminals 80 to even when the substrate 10 is in a wafer state. In addition, even when the distance between the substrate 10 of the first piezoelectric vibrating body 101 and the substrate 10 of the second piezoelectric vibrating body 102 is reduced to approximately 20 μm, it is possible to easily form the terminals 80 to 86. For example, in a case of forming the terminals 80 to 86 by a sputtering method, it is necessary to perform sputtering from a direction perpendicular to the thickness direction of the substrate 10 and it may not be possible to easily form the terminals 80 to 86.
Furthermore, the non-electrolytic plating layer can be formed simply by immersion in liquid. Therefore, in the piezoelectric driving apparatus 300, forming the terminals 80 to 86 makes it possible to suppress damage to the wiring layer 352. In addition, in the piezoelectric driving apparatus 300, for example, it is possible to form the terminals 80 to 86 at low cost.
Furthermore, in the piezoelectric driving apparatus 300, for example, it is possible to lower the resistance in comparison with a case of using Ag paste as a terminal. For example, the specific resistance of the Ag paste is 2 Ωcm and the specific resistance of the Ni—P layer of the terminals 80 to 86, which is a non-electrolytic plating layer, is 0.7 Ωcm.
The piezoelectric driving apparatus 300 includes the first insulating portion 344 provided between the substrate 10 and the wiring layer 352 of the first piezoelectric vibrating body 101 and the second insulating portion 346 provided between the substrate 10 and the wiring layer 352 of the second piezoelectric vibrating body 102, and the terminals 80 to 86 are connected to the side surfaces 340a and 342a of the insulating portions 344 and 346. Therefore, in the piezoelectric driving apparatus 300, in a case where the terminals 80 to 86 which are non-electrolytic plating layers are grown isotropically from the side surface 352a of the wiring layer 352, it is possible to suppress the terminals 80 to 86 from coming in contact with the substrate 10 of the piezoelectric vibrating bodies 101 and 102 due to the insulating portions 344 and 346. Due to this, in the piezoelectric driving apparatus 300, between the substrates 10 of the piezoelectric vibrating bodies 101 and 102, it is possible to suppress the leakage current from flowing via the terminals 80 to 86.
In the piezoelectric driving apparatus 300, the substrate 10 is formed of the silicon substrate 11a, and the underlayer 11b which is an insulating layer provided on the silicon substrate 11a. Therefore, in the piezoelectric driving apparatus 300, even when the terminals 80 to 86 are in contact with the substrate 10, it is possible to suppress the leakage current from flowing via the terminals 80 to 86 between the substrates 10 of the piezoelectric vibrating bodies 101 and 102.
Here, the substrate 10 may be formed only of the silicon substrate 11a formed of a high-resistance silicon (for example, a silicon which exceeds 10000 Ωcm). Also in such a case, it is possible to suppress the leakage current from flowing via the terminals 80 to 86 between the substrates 10 of the piezoelectric vibrating bodies 101 and 102. However, in a case of using a high-resistance silicon, the cost is high in comparison with a case of using a normal silicon substrate.
In the piezoelectric driving apparatus 300, the flexible substrate 120 and the piezoelectric vibrating bodies 101 and 102 are bonded to the adhesive 3 which has an insulating characteristic. Therefore, in the piezoelectric driving apparatus 300, it is possible to suppress the leakage current from flowing via the terminals 80 to 86 between the substrates 10 of the piezoelectric vibrating bodies 101 and 102.
In the piezoelectric driving apparatus 300, the terminals 80 to 86 have a gold layer provided so as to cover the Ni—P layer. Therefore, in a case where the material of the wiring layer 124 of the flexible substrate 120 is gold, it is possible to bond the terminals 80 to 86 and the flexible substrate 120 by the metal bond (Au—Au bond). Furthermore, in the piezoelectric driving apparatus 300, for example, due to the Au—Au bond and the adhesive 3, it is possible to strongly bond the flexible substrate 120 and the piezoelectric vibrating bodies 101 and 102. Accordingly, in the piezoelectric driving apparatus 300, due to the vibration of the vibrating body portion 12, it is possible to suppress the cutting of the connection between the flexible substrate 120 and the piezoelectric vibrating bodies 101 and 102. Thus, the piezoelectric driving apparatus 300 can have a high reliability. In addition, it is possible to improve the quality in the piezoelectric driving apparatus 300.
In the piezoelectric driving apparatus 300, the terminals 80 to 86 have a palladium layer provided between the Ni—P layer and the gold layer. Therefore, in the piezoelectric driving apparatus 300, the diffusion between the Ni—P layer and a gold layer can be suppressed by the palladium layer.
Next, description will be given of the method of manufacturing a piezoelectric driving apparatus 300 according to the second embodiment with reference to the drawings.
The first piezoelectric vibrating body 101 and the second piezoelectric vibrating body 102 are basically formed by the same manufacturing method. Accordingly, in the following, description will be given of a method of manufacturing the first piezoelectric vibrating body 101 using
As shown in
Here, the substrate 10 may be in a wafer state. That is, although not shown, a frame portion is provided on the periphery of the substrate 10 and the substrate 10 may be connected to the frame portion via a cut-away portion. In such a case, the substrate 10, the frame portion, and the cut-away portion are integrally provided.
Next, the piezoelectric body layer 34 is formed on the first electrode 32 (S2). The piezoelectric body layer 34 is, for example, formed by patterning after repeating the forming of the precursor layer by a liquid phase method and the crystallization of the precursor layer. The liquid phase method is a method of forming a film with a thin-film material using a raw material solution which includes a constituent material of the thin film (piezoelectric body layer), specifically, a sol-gel method, a metal organic deposition (MOD) method, or the like. The crystallization is performed by a heat treatment at 700° C. to 800° C. in an oxygen atmosphere. In this step, it is possible to form the insulating layer 35 on the first conductive layer 33 (refer to
Next, the second electrode 36 is formed on the piezoelectric body layer 34 (S3). The second electrode 36 is, for example, formed with the same method as the first electrode 32. Although not shown, the patterning of the second electrode 36 and the patterning of the piezoelectric body layer 34 may be performed as the same step. In this step, it is possible to form the second conductive layer 37 on the insulating layer 35 (refer to
Through the above steps, it is possible to form the piezoelectric element 30 on the vibrating body portion 12 of the substrate 10.
As shown in
Next, the wiring layer 350 is formed on the second electrode 36 and on the insulating layer 340 (S5). The wiring layer 350 is formed by, for example, a plating (electroplating) method, film-forming by sputtering and patterning, or the like.
Next, the non-electrolytic plating layer 351 is formed so as to cover the wiring layer 350 (S6). The non-electrolytic plating layer 351 is formed by non-electrolytic plating. Specifically, after selectively attaching palladium as a catalyst to the surface of the wiring layer 350, the non-electrolytic plating layer 351 is selectively formed on the surface of the wiring layer 350 by non-electrolytic plating.
As shown in
Through the above steps, it is possible to form the insulating portions 344 and 346 (refer to
Next, the wiring layer 352 is formed on the electrodes 32 and 36 and on the insulating layer 342 (S8). The wiring layer 352 is, for example, is formed by the same method as the wiring layer 350.
Through the above steps, it is possible to form the first piezoelectric vibrating body 101 and the second piezoelectric vibrating body 102. Here, in a case where the substrate 10 is in a wafer state, the first piezoelectric vibrating body 101 and the second piezoelectric vibrating body 102 may be formed on different wafers.
As shown in
As shown in
As shown in
In step (S11), the terminals 80 to 86 are connected to the side surfaces 352a of the wiring layers 352 of the piezoelectric vibrating bodies 101 and 102 and are formed so as to protrude outward further than the side surface 10c of the substrate 10 of the piezoelectric vibrating bodies 101 and 102. The terminals 80 to 86 are formed so as to connect to the side surfaces 340a and 342a of the insulating portions 344 and 346. The terminals 80 to 86 are formed so as to be separated from the substrates 10 of the piezoelectric vibrating bodies 101 and 102.
Here, although not shown, in a case where the substrate 10 is a wafer state, after step (S11), a cut-away portion is cut away by etching or the like to separate the substrate 10 from the frame portion (chip forming).
Through the above steps, it is possible to manufacture the piezoelectric driving apparatus 300.
The method of manufacturing a piezoelectric driving apparatus 300 includes a step (S11) of forming terminals 80 to 86 which are connected to the side surfaces 352a of the wiring layers 352 of the piezoelectric vibrating bodies 101 and 102 so as to protrude outward further than the side surfaces 10c of the substrates 10 of the piezoelectric vibrating bodies 101 and 102. Therefore, in the method of manufacturing a piezoelectric driving apparatus 300, it is possible to manufacture the piezoelectric driving apparatus 300 which can be reduced in size.
Next, description will be given of the piezoelectric driving apparatus according to a modification example of the second embodiment with reference to the drawings.
Below, in the piezoelectric driving apparatus 400 according to the modification example of the second embodiment, the same reference numerals are given to the member which have the same functions as the constituent members of the piezoelectric driving apparatus 300 according to the second embodiment and detailed description thereof will be omitted.
As shown in
In the piezoelectric driving apparatus 400, the first piezoelectric vibrating body 101 the second piezoelectric vibrating body 102, and the terminals 80, 82, 84, and 86 form a bonded body 410. A plurality of the bonded bodies 410 are provided. In the illustrated example, two of the bonded bodies 410 are provided. A plurality of the bonded bodies 410 are laminated in the thickness direction of the substrate 10.
In the adjacent bonded bodies 410, the substrate 10 of the first piezoelectric vibrating body 101 of one of the bonded bodies 410 and the substrate 10 of the second piezoelectric vibrating body 102 of the other bonded body 410 are bonded by an adhesive 402. The adhesive 402 has, for example, an insulating characteristic.
In the piezoelectric driving apparatus 400, a plurality of the bonded bodies 410 are laminated in the thickness direction of the substrate 10. Therefore, in the piezoelectric driving apparatus 400, it is possible to achieve a higher output in comparison with a case where only one bonded body 410 is formed.
Furthermore, in the piezoelectric driving apparatus 400, even in a case where a plurality of the bonded bodies 410 are laminated, it is possible to use the flexible substrate 120 and the routing of the external wiring can be simplified. Therefore, in the piezoelectric driving apparatus 400, it is possible to easily electrically connect the driving circuit 110 and the wiring layer 352.
Next, description will be given of a piezoelectric driving apparatus according to the third embodiment with reference to the drawings.
Here, piezoelectric actuators (piezoelectric driving apparatuses) for driving a driven body by vibrating a piezoelectric body are used in various fields since a magnet or a coil is not necessary. For example, the piezoelectric driving apparatus disclosed in JPA-2004-320979 is formed with four piezoelectric elements disposed in two rows and two columns on each of two surfaces of a plate-like member, and is formed to generate vibration using eight piezoelectric elements in total. At one end of the plate-like member, a protrusion is provided for rotating the rotor by coming in contact with the rotor as a driven body. When an AC voltage is applied to the two piezoelectric elements disposed diagonally out of the four piezoelectric elements, the two piezoelectric elements perform an expansion and contraction movement and the protrusion performs a reciprocating movement or an elliptical movement accordingly. Then, the rotor as a driven member is rotated in a predetermined rotational direction depending on the reciprocating movement or elliptical movement of the protrusion of the reinforcing plate. In addition, switching from the two piezoelectric elements to which an AC voltage is applied to the two other piezoelectric elements makes it possible to rotate the rotor in the opposite direction.
In addition, a piezoelectric driving apparatus with a stack structure for increasing the output by superimposing piezoelectric driving bodies (piezoelectric vibrating bodies) in the thickness direction is known (for example, JP-A-08-237971). The piezoelectric vibrating bodies of the piezoelectric driving apparatus are supported by an elastic support body.
For example, in a case where the motor is formed to generate power using a piezoelectric driving apparatus, one of the basic requirements is to increase the driving force (output). As an example, in the apparatus disclosed in JP-A-2008-227123 described above, an attempt is made to increase the output by the stack structure.
However, in a case where vibrating bodies where a piezoelectric element is formed on the surface of the plate-like member are stacked (laminated), a difference in the thickness is generated between the region of the plate-like member where the piezoelectric element is formed and the region where the piezoelectric element is not formed. Therefore, in the step of bonding or the like in the manufacturing of the laminated body, the plate-like member is easily damaged. In addition, even in a case where the plate-like member is not damaged, defects may be generated in the vibration characteristics when the lamination is carried out in a state where residual stress is generated in the plate-like member.
In addition, in a case where the thickness is different between a fixing location (fixing portion) of the piezoelectric driving apparatus provided in order to fix the piezoelectric driving apparatus with respect to the structural material or the like and a portion (vibrating portion) which vibrates the piezoelectric driving apparatus, in a case of forming a laminated body, the piezoelectric driving apparatus is easily cracked or broken in the step of bonding or the like and residual stress tends to remain. Therefore, in particular, there was a risk of damage in the region (the connecting portion or the like) between the fixing portion and the vibrating portion.
An object according to some embodiments of the invention is to provide a piezoelectric driving apparatus where a plurality of vibrating units are laminated in a state with favorable flatness and where damage or the like does not easily occur, and a motor, robot, and pump provided with such a piezoelectric driving apparatus.
A piezoelectric driving apparatus 500 of the third embodiment includes a plurality of vibrating units 501. Then, the piezoelectric driving apparatus 500 is formed by arranging the vibrating units 501 so as to overlap. Below, after giving description of the vibrating units 501, description will be given of thickness, arrangement, and the like of the vibrating units 501.
First, description will be given of the vibrating units of piezoelectric driving apparatus according to the third embodiment with reference to the drawings.
The vibrating unit 501 of the present embodiment includes the vibrating plate 510, a first electrode 532, a first piezoelectric body layer 534, a second electrode 536, a third electrode 542, a second piezoelectric body layer 544, and a fourth electrode 546.
The vibrating plate 510 has a flat shape. As shown in
At one end of the vibrating plate 510 in the longitudinal direction, the protrusion 518 is provided. The protrusion 518 may be integrally provided with the vibrating portion 514, or may be formed separately and provided in contact with the vibrating portion 514 using adhesive or the like. The protrusion 518, for example, comes in contact with a rotor (described below) which is not shown in the diagram and the protrusion 518 moves to follow a locus of a circle or an ellipse in plan view to be able to rotate the rotor. The movement of the protrusion 518 is realized by the expanding and contracting vibration and the bending vibration of the vibrating portion 514. Although the form of the vibration of the vibrating portion 514 is arbitrary, the vibration is implemented by a piezoelectric element provided on the vibrating portion 514. The material of the protrusion 518 is, for example, ceramics (specifically, alumina (Al2O3), Zirconia (ZrO2), silicon nitride (Si3N), or the like).
On the other hand, as shown in
In the illustrated example, in plan view, the fixing portions 512 are provided on both sides of the vibrating portion 514 in the lateral direction. The position and number of the fixing portions 512 to be provided is not particularly limited. The size of the fixing portion 512 is also not particularly limited and, for example, may be larger or smaller than the vibrating portion 514 in a range in which the vibration of the vibrating portion 514 is not inhibited.
In the illustrated example, three holes 511 formed so as to be suitable for screwing or the like are formed in each of the fixing portions 512. The holes 511 are through holes passing through the vibrating plate 510. The holes 511 may be used to fix a plurality of vibrating units 501 to each other, or may be used in order to fix a set of the vibrating units 501 to another member when using the holes 511 to form the piezoelectric driving apparatus 500. Here, in the illustrated example, an aspect where the holes 511 are formed in the fixing portion 512 is illustrated; however, the holes 511 are not always necessary as long as it is possible to fix a plurality of the vibrating units 501 to each other by another means or configuration (for example, a pinching member (a clip, or the like)), or to fix a set of the vibrating units 501 to another member.
The vibrating unit 501 is fixed by the fixing portion 512 of the vibrating plate 510; however, a portion (denoted by the reference numeral of a fixing portion 512a below in the vibrating unit 501) corresponding to the fixing portion 512 of the vibrating unit 501 is fixed by fixing the vibrating plate 510. In addition, in the fixing portion 512 of the vibrating plate 510 of the vibrating unit 501 of the present embodiment, the third electrode 542, a second piezoelectric body layer 544, and the fourth electrode 546 are formed. Such an arrangement may be formed to avoid the holes 511 (refer to
In the vibrating plate 510, the connecting portion 516 which connects the fixing portion 512 and the vibrating portion 514 is formed. The connecting portion 516 is provided such that the fixing portion 512 supports the vibrating portion 514. The connecting portion 516 supports the vibrating portion 514; however, the connecting portion 516 is preferably provided so as to not inhibit the vibration (operation) of the vibrating portion 514. For example, the connecting portion 516 is provided in the vicinity of the joint of the vibration when the vibrating portion 514 is vibrated. In addition, for example, as illustrated, the connecting portion 516 is formed to be thinner and with a lower mechanical strength than the vibrating portion 514. However, since the vibrating portion 514 is, for example, pressed against the rotor, or the like, the connecting portion 516 is designed so as to have a strength which is not impaired by the above biasing force.
In the illustrated example, the connecting portions 516 are formed so as to extend three at a time from one vibrating portion 514 with respect to two of the fixing portions 512. The positions, number, shapes, and the like of the connecting portions 516 to be provided are not limited and can be appropriately designed according to the purpose of the piezoelectric driving apparatus 500.
The vibrating plate 510 is, for example, a silicon substrate. The material of the vibrating plate 510 may be silicon, metal, oxide, nitride, or the like and, in addition, may take the form of a laminate or composite material. The vibrating plate 510 can be appropriately provided with a layer functioning as a conductor (an electrode, or the like), a dielectric body, a piezoelectric body, an insulator or the like. In addition, these layers may be provided over the entire surface of the vibrating plate 510, or may be provided on both surfaces of the vibrating plate 510.
A layer such as a conductor (an electrode, or the like), a dielectric body, a piezoelectric body, an insulator or the like is formed on the vibrating plate 510. The thickness of the vibrating plate 510 does not need to be uniform. For example, the thickness of a connecting portion 516a of the vibrating plate 510 may be smaller than the thickness of the vibrating portion 514 and the fixing portion 512. In addition, specific portions of the vibrating plate 510 may have different thicknesses from the thicknesses of other portions. Such a structure can, for example, be comparatively easily formed in a case where the vibrating plate 510 is formed by a silicon substrate. However, as will be described in detail below, in a state where at least the vibrating unit 501 is formed, the thickness of the vibrating unit 501 of the portion (the fixing portion 512a) corresponding to the fixing portion 512 of the vibrating plate 510 is preferably the same as the thickness of the vibrating unit 501 of the portion (denoted by the reference numeral of a vibrating portion 514a below in the vibrating unit 501) corresponding to the vibrating portion 514.
Here, in the present specification, the “same” refers not only to being exactly the same, but also includes a case of being the same after taking measurement errors into consideration and a case of being the same within a range which does not impair the functions. Accordingly, the expression “one thickness is the same as another thickness” takes into account measurement errors, and has the meaning that the difference between the two thicknesses is within ±20% of the one thickness, preferably within ±15%, more preferably within ±10%, even more preferably within ±5%, and particularly preferably within ±3%.
The first electrode 532 is provided above the vibrating portion 514 of the vibrating plate 510. Between the first electrode 532 and the vibrating plate 510, for example, a layer having a function of adhesion, crystal control, orientation control, insulation, or the like may be formed.
The first electrode 532 may be formed over the entire surface of the vibrating portion 514, or may be formed on a portion of the vibrating portion 514. In the example shown in
Here, in
Some or all of the region provided in the vibrating portion 514 of the first electrode 532 is disposed opposite to the second electrode 536 and this portion functions as one electrode of the piezoelectric element. The first electrode 532 is formed of a material having conductivity such as a metal, an alloy, a conductive oxide, or the like.
The thickness of the first electrode 532 is, for example, 10 nm to 1 μm, preferably 20 nm to 800 nm, more preferably 30 nm to 500 nm, and even more preferably 50 nm to 300 nm.
The first electrode 532 may, for example, be formed of an iridium layer, and a platinum layer provided on the iridium layer. In such a case, the thickness of the iridium layer is, for example, 5 nm to 100 nm. In addition, the thickness of the platinum layer is, for example, 50 nm to 300 nm.
Here, examples of the material of the first electrode 532 include various metals such as nickel, iridium, platinum, Ti, Ta, Sr, In, Sn, Au, Al, Fe, Cr, and Cu, conductive oxides thereof (for example, iridium oxide), complex oxides of strontium and ruthenium (SrRuOx:SRO), composite oxides of lanthanum and nickel (LaNiOx:LNO), and the like. The first electrode 532 may have a single-layer structure of the illustrated materials, or may have a structure in which a plurality of materials are laminated. In addition, although not illustrated, the first electrode 532 can be etched or patterned by a typical method in semiconductor manufacturing or the like.
The first piezoelectric body layer 534 is provided above the first electrode 532 above the vibrating portion 514 of the vibrating plate 510. Between the first electrode 532 and the first piezoelectric body layer 534, for example, a layer having a function of adhesion, crystal control, orientation control, insulation, or the like may be formed. Here, the material of the adhesive layer in a case of providing the adhesive layer is, for example, a TiW layer, a Ti layer, a Cr layer, an NiCr layer, or a laminate thereof. The first piezoelectric body layer 534 is positioned between the first electrode 532 and the second electrode 536.
The first piezoelectric body layer 534 may be formed over the entire surface of the first electrode 532, or may be formed above a portion thereof. In addition, the first piezoelectric body layer 534 may be formed above the vibrating plate 510 where the first electrode 532 is not formed. As shown in
In the example shown in
The first piezoelectric body layer 534 forms a piezoelectric element in a portion interposed between the first electrode 532 and the second electrode 536 and is able to change shape according to an electromechanical conversion operation by the application of a voltage from both electrodes.
The thickness of the first piezoelectric body layer 534 is, for example, 50 nm to 20 μm, and preferably 1 μm to 7 μm. Accordingly, a piezoelectric element formed by overlapping and arranging the first electrode 532, the first piezoelectric body layer 534, and the second electrode 536 is a thin-film piezoelectric element. As long as the thickness of the first piezoelectric body layer 534 is in this range, it is possible to obtain a sufficient output from the vibrating unit 501 and dielectric breakdown does not easily occur even when the voltage applied to the first piezoelectric body layer 534 is increased. In addition, as long as the thickness of the first piezoelectric body layer 534 is in this range, cracks are not easily generated in the first piezoelectric body layer 534.
Examples of the material of the first piezoelectric body layer 534 include perovskite-type oxide piezoelectric materials. More specifically, the material of the first piezoelectric body layer 534 is preferably a perovskite-type oxide represented by the general formula ABO3 (for example, A includes Pb and B includes Zr and Ti). Specific examples of such materials include lead zirconate titanate (Pb(Zr, Ti) O3) (may be abbreviated below as “PZT”), lead zirconate titanate niobate (Pb(Zr, Ti, Nb) O3) (may be abbreviated below as “PZTN”), barium titanate (BaTiO3), potassium sodium niobate ((K, Na) NbO3), and the like. Among these, as the material of the first piezoelectric body layer 534, PZT and PZTN are particularly suitable as the piezoelectric characteristics are good. In addition, although not illustrated, the first piezoelectric body layer 534 can be etched or patterned using a typical method in semiconductor manufacturing or the like.
The second electrode 536 is provided above the first piezoelectric body layer 534. Between the second electrode 536 and the first piezoelectric body layer 534, for example, a layer having a function of adhesion, crystal control, orientation control, insulation, or the like may be formed. Here, the material of the adhesive layer in a case of providing the adhesive layer is, for example, a TiW layer, a Ti layer, a Cr layer, an NiCr layer, or a laminate thereof.
Some or all of the region provided in the vibrating portion 514 of the second electrode 536 is disposed opposite the first electrode 532 and this portion functions as one electrode of the piezoelectric element.
As long as the second electrode 536 can form a piezoelectric element by forming a set with the first electrode 532 and the first piezoelectric body layer 534, the second electrode 536 may be formed over the entire surface of the vibrating portion 514. That is, as long as the first electrode 532 is patterned, it is possible to form a set of a predetermined piezoelectric element even when the second electrode 536 is formed over the entire surface of the vibrating portion 514. That is, in the illustrated example, the first electrode 532 is a common electrode of the plurality of piezoelectric elements and the second electrode 536 is an individual electrode of the plurality of piezoelectric elements; however, the second electrode 536 may be a common electrode of the plurality of piezoelectric elements and the first electrode 532 may be an individual electrode of the plurality of piezoelectric element. In addition, the second electrode 536 may be electrically connected to the fourth electrode 546. The thickness of the second electrode 536 is, for example, 1 μm to 10 μm. The second electrode 536 is, for example, a Cu layer, an Au layer, an Al layer, or a laminate thereof.
As described above, the piezoelectric element is formed above the vibrating portion 514 of the vibrating plate 510 by the set of the first electrode 532, the first piezoelectric body layer 534, and the second electrode 536; however, the shape, number, arrangement, and the like of the piezoelectric element are arbitrary as long as it is possible for the vibrating portion 514 to generate a predetermined vibration. In the illustrated example, five of the piezoelectric elements are formed above the vibrating portion 514. Then, it is possible for the vibrating unit 501 to carry out bending vibration and expanding and contracting vibration by applying an appropriate voltage to the electrodes of each of the piezoelectric elements using wiring which is not shown.
The vibrating unit 501 has the third electrode 542 on the fixing portion 512a. The third electrode 542 is provided above the fixing portion 512 of the vibrating plate 510. Between the third electrode 542 and the vibrating plate 510, for example, a layer having a function of adhesion, crystal control, orientation control, insulation, or the like may be formed.
The third electrode 542 may be formed on the entire surface of the fixing portion 512, or may be formed on a portion of the fixing portion 512. In the example shown in
Some or all of the region provided on the fixing portion 512 of the third electrode 542 is disposed opposite to the fourth electrode 546. The third electrode 542 may function as one electrode of a capacitor in this part. The third electrode 542 is formed of a material having conductivity such as a metal, an alloy, or a conductive oxide. The thickness and material of the third electrode 542 can, for example, be the same as the first electrode 532.
The vibrating unit 501 has a second piezoelectric body layer 544 on the fixing portion 512a. The second piezoelectric body layer 544 is provided above the third electrode 542 above the fixing portion 512 of the vibrating plate 510. Between the third electrode 542 and the second piezoelectric body layer 544, for example, a layer having a function of adhesion, crystal control, orientation control, insulation, or the like may be formed. The second piezoelectric body layer 544 is positioned between the third electrode 542 and the fourth electrode 546.
The second piezoelectric body layer 544 may be formed over the entire surface of the third electrode 542, and may be formed above a portion thereof. In addition, the second piezoelectric body layer 544 may be formed above the vibrating plate 510 where the third electrode 542 is not formed. As shown in
In the example shown in
The second piezoelectric body layer 544 can form a capacitor in a portion interposed between the third electrode 542 and the fourth electrode 546. Here, since the second piezoelectric body layer 544 does not easily change shape due to being provided in the fixing portion 512 and constrained by a structural member such as a screw and, since the applied electric energy is not easily converted into mechanical energy, the second piezoelectric body layer 544 can be used as a good capacitor (condenser). The thickness and material of the second piezoelectric body layer 544 are the same as those of the first piezoelectric body layer 534.
The vibrating unit 501 has the fourth electrode 546 on the fixing portion 512a. The fourth electrode 546 is provided above the second piezoelectric body layer 544. Between the fourth electrode 546 and the second piezoelectric body layer 544, for example, a layer having a function of adhesion, crystal control, orientation control, insulation, or the like may be formed.
The fourth electrode 546 may be formed over the entire surface of the fixing portion 512. For example, as long as the third electrode 542 is patterned, it is possible to form a predetermined capacitor even when the fourth electrode 546 is formed over the entire surface of the fixing portion 512. In the illustrated example, the third electrode 542 is a common electrode of the plurality of capacitors and the fourth electrode 546 is an individual electrode of the plurality of capacitors; however, the fourth electrode 546 may be a common electrode of the plurality of capacitors, and the third electrode 542 may be a separate electrode of the plurality of capacitors. In addition, the fourth electrode 546 may be electrically connected to the second electrode 536.
Some or all of the region provided on the fixing portion 512 of the fourth electrode 546 is disposed to oppose the third electrode 542, and this portion can function as one electrode of the capacitor. The thickness and material of the fourth electrode 546 can be the same as the second electrode 536.
The vibrating unit 501 of the third embodiment can include other configurations. As such configurations, for example, wiring, a layer of an insulator for wiring, a layer for adhesion to laminate a plurality of vibrating units 501, and the like may be included. Below, description will be given of an insulating layer 560 for providing a wiring layer 550 and the wiring layer 550 which electrically connects each of the electrodes described above.
The vibrating unit 501 of the present embodiment includes the wiring layer 550 provided above the second electrode 536 and the fourth electrode 546. The wiring layer 550 is provided above the insulating layer 560 (described below). Providing a contact hole in the insulating layer 560 or the piezoelectric body layer positioned below makes it possible for the wiring layer 550 to electrically connect to a conductor (an electrode or the like) positioned below.
The wiring layer 550 is electrically connected to at least one of the second electrode 536 and the fourth electrode 546. In addition, the wiring layer 550 may be connected to the first electrode 532 and the third electrode 542. The wiring layer 550 can form wiring by being appropriately patterned. For example, the wiring layer 550 can form wiring and, in addition, may form a pad which is not shown (terminal for external connection) or the like.
The thickness of the wiring layer 550 is, for example, 50 nm to 10 μm, preferably 100 nm to 5 μm, and more preferably 200 nm to 3 μm and, as long as the thickness is in this range, it is possible to ensure sufficient conductivity.
Furthermore, as shown in
The material of the wiring layer 550 is not particularly limited and is, for example, formed of various metals such as nickel, iridium, platinum, Ti, Ta, Sr, In, Sn, Au, Al, Fe, Cr, and Cu, or conductive materials such as alloys thereof. In addition, although not illustrated, the wiring layer 550 can be etched or patterned by a typical method in semiconductor manufacturing or the like. In addition, forming a contact hole below the wiring layers 550 and forming the via 552 to carry out the electrical connection with the conductor below, or the like can be performed using a typical method in semiconductor manufacturing or the like.
The wiring layer 550 can be provided as a plurality of layers and, for example, may be formed as multi-layer wiring. In addition, in order to make the wiring layer 550 the multi-layer wiring, the insulating layer 560 described below may be formed as a plurality of layers.
The insulating layer 560 is provided above at least the second electrode 536 and the fourth electrode 546. The insulating layer 560 may be provided between each of the electrodes and the wiring layer 550. Furthermore, the insulating layer 560 has a function of insulating the electrodes or the wiring. In addition, the insulating layer 560 may be provided above the wiring layer 550. When the insulating layer 560 is formed above the wiring layer 550, for example, in a case where the vibrating plate 510 of the adjacent vibrating unit 501 is conductive, or the like, it is possible to insulate between the adjacent vibrating units 501.
The insulating layer 560 is an oxide insulator such as, for example, silicon oxide, silicon nitride, or aluminum oxide, and can be formed using a typical method in semiconductor manufacturing or the like. In addition, it is possible to form a contact hole at a predetermined position in the insulating layer 560 and to connect to a predetermined wiring by forming a via using a typical method in semiconductor manufacturing or the like.
In the example shown in
The vibrating unit 501 of the present embodiment is formed so as to be substantially the same thickness in the fixing portion 512 and the vibrating portion 514 of the vibrating plate 510. For example, as shown in
That is, in consideration of measurement errors, the difference between the thickness α and the thickness β is, for example, within ±20% of the thickness α, preferably within ±15%, more preferably within ±10%, even more preferably within ±5%, and particularly preferably within ±3%. Here, the same applies to a case where the piezoelectric element or the like is formed on both surfaces of the vibrating plate 510, and the total thickness α of the vibrating portion 114a and the total thickness β of the fixing portion 512a are formed to be the same.
In addition, the thickness of each of the vibrating plate 510, the first electrode 532, the first piezoelectric body layer 534, the second electrode 536, the insulating layer 560, the wiring layer 550, and the insulating layer 560 and the thickness of each of the vibrating plate 510, the third electrode 542, the second piezoelectric body layer 544, the fourth electrode 546, the insulating layer 560, the wiring layer 550, and the insulating layer 560, need not correspond to each other. That is, for example, the thickness of the first piezoelectric body layer 534 in the vibrating portion 114a and the thickness of the second piezoelectric body layer 544 in the fixing portion 512a may be different and it is sufficient if the total thickness α and the total thickness β are made to be the same by adjusting the thickness of the other configurations (for example, the insulating layer 560 or the vibrating plate 510).
However, when manufacturing the vibrating unit 501 of the present embodiment, since each layer of the vibrating portion 514a and the fixing portion 512a can be formed in the same step, it is possible to easily set the total thickness α and the total thickness β to be the same by aligning each of the thicknesses.
The number of the vibrating units 501 to be overlapped is not particularly limited and is appropriately set according to the driving force (output) or application of the piezoelectric driving apparatus 500. Even the aspect where the vibrating units 501 are overlapped and disposed is not particularly limited and, for example, as illustrated, it is possible to arrange the fixing portions 512 of each of the vibrating units 501 to overlap each other.
The method for overlapping and arranging the vibrating units 501 is not particularly limited and, for example, it is possible to illustrate a mechanical fixing method of inserting a common screw with respect to the hole 511 of the vibrating unit 501, a method of adhering between the plurality of vibrating units 501 using an adhesive or the like, a method of thermo-compression bonding between the plurality of vibrating units 501, or the like. Furthermore, in a case of adhering between the plurality of vibrating units 501, it is sufficient if at least the fixing portion 512a of the vibrating unit 501 is adhered; however, the vibrating portion 514a of the vibrating unit 501 may be adhered. In addition, although the connecting portion 516a of the vibrating unit 501 may be adhered, it is preferable not to inhibit the vibration of the vibrating portion 514a in such a case.
Here, if the total thickness α of the vibrating portion 514a and the total thickness β of the fixing portion 512a are different, when the plurality of vibrating units 501 are pressed to each other, bending stress is generated in the direction in which each of the vibrating units 501 departs from the surface of the vibrating plate 510. In other words, among the vibrating portion 514a and the fixing portion 512a of the vibrating unit 501, when a thinner region is overlapped and pressed so as to be closer than a thicker region, bending stress is generated in the connecting portion 516a which is present therebetween. Moreover, the connecting portion 516a of the vibrating unit 501 is formed to be structurally weak in comparison with to the vibrating portion 514a and the fixing portion 512a. Therefore, the stress described above tends to concentrate on the connecting portion 516a. In addition, the extent of such bending stress is increased as the number of the overlapped vibrating units 501 increases and a difference in the thickness is accumulated. When such stress is generated, the vibrating unit 501 may be destroyed and, even in a case where the vibrating unit 501 is not destroyed, the piezoelectric driving apparatus 500 is formed with stress still remaining in the connecting portion 516a.
In contrast, in the vibrating unit 501 of the present embodiment, the total thickness α of the vibrating portion 514a and the total thickness β of the fixing portion 512a are the same. Due to this, when overlapped and disposed, bending stress is not easily generated and, in particular, it is possible to suppress damage or the concentration of the stress in the connecting portion 516a. Accordingly, when overlapped, it is possible to form the piezoelectric driving apparatus 500 in a state where damage is not easily caused in the vibrating unit 501 and stress is not easily generated in the connecting portion 516a. In addition, this effect becomes more significant as the number of the vibrating units 501 is increased.
Here, the vibrating portion 514a and the fixing portion 512a of the vibrating unit 501 have a greater mechanical strength than the connecting portion 516a. For this reason, in the vibrating portion 514a and in the fixing portion 512a, even if the thickness of the vibrating unit 501 is non-uniform, stress or damage is not easily generated in the vibrating unit 501.
As described above, by the set of the third electrode 542, the second piezoelectric body layer 544 and the fourth electrode 546, a structure which can be a capacitor is formed above (on the fixing portion 512a of the vibrating unit 501) the fixing portion 512 of the vibrating plate 510; however, the shape, number, arrangement, and the like of the capacitors is arbitrary. In the illustrated example, two of the structures which can become capacitors are formed for each of two of the fixing portions 512, making a total of four. Accordingly, when each electrode is appropriately connected, it is possible for the structure to function as a capacitance (condenser).
Here, the set of the third electrode 542, the second piezoelectric body layer 544, and the fourth electrode 546 can function as a capacitor, but may be used simply as a structural material. That is, in the vibrating unit 501 of the third embodiment, the third electrode 542 which is disposed on the fixing portion 512a, the second piezoelectric body layer 544, and the fourth electrode 546 may be used only in order to set the thickness β of the fixing portion 512a to be the same as the thickness α of the vibrating portion 514a. In other words, in the vibrating unit 501 of the third embodiment, in order to easily set the thickness β of the fixing portion 512a and the thickness α of the vibrating portion 114a to be the same, the same laminate structure as the piezoelectric element is also disposed in the fixing portion 512a, but the laminate structure can also be used as a capacitor.
In the vibrating unit 502 shown in
As shown in
The driving circuit 570 has at least a driving voltage generation circuit 572. In the illustrated example, the first electrode 532 and the third electrode 542 connected to each other have a ground potential, and each of the piezoelectric elements and the capacitor is appropriately connected to the driving voltage generation circuit 572. The driving circuit 570 subjects the vibrating unit to ultrasonic vibration by applying a periodically changing AC voltage or a pulsating voltage between predetermined electrodes. Here, the “pulsating voltage” has the meaning of a voltage where a DC offset is applied to an AC voltage and the orientation of the voltage (electric field) is a direction from one electrode to the other electrode.
In a case where the vibrating unit 501 of the third embodiment has the wiring layer 550, an inductor may be formed using the wiring layer 550. The inductor may be formed by forming each of the electrodes described above and another conductive layer in addition to the wiring layer 550.
The inductor is, for example, a coil. The coil is not particularly limited and examples thereof include a winding of an electrical conductor. The form of the winding can be designed as appropriate. In the vibrating unit of the third embodiment, the wiring layer 550 is formed of a single layer or multiple layers, but in a case of forming the winding with a single layer, for example, the winding may take the form of a planar spiral or a one-turn loop. In addition, in a case where the wiring layer 550 is formed of a plurality of layers, the winding can form a coil in a form such that the conductor is wound into a cylindrical shape by forming a via or the like and wiring appropriately. Furthermore, it is also possible to form a coil in a form such that the conductor is wound into a cylindrical shape by using the overlapping arrangement of the vibrating unit 501 of the third embodiment and electrically connecting the wiring layer 550 of the vibrating units disposed adjacently (refer to
Furthermore, in each of the vibrating units shown in
In the vibrating unit 503 shown in
In the vibrating unit 503 shown in
The size and shape of the inductors 554 are arbitrary and can be designed to be suitable for a predetermined circuit configuration. In addition, the spiral shape inductor 554 can, for example, also be formed in the layer in which the first electrode 532 is formed. However, since the inductor 554 can reduce the wiring resistance, the inductor 554 is more preferably formed in the wiring layer 550.
In the vibrating unit 505 shown in
The mechanical output of the piezoelectric driving apparatus Cd can be conceptually considered as the resistance R2 (mechanical loss). Accordingly, supplying a large amount of the energy applied from the power source S to the acoustic element A makes it possible to increase the mechanical output of the piezoelectric driving apparatus Cd. In other words, it is preferable to reduce the energy consumed by the electric element E.
The power supplied from the power source S is distributed to the electric element E and the acoustic element A. Accordingly, the smaller the impedance of both ends of the electrical element E than the impedance of both ends of the acoustic element A, the more power it is possible to distribute to the acoustic element A.
Here, in the electrical element E, when resonance is caused, it is possible to reduce the apparent impedance of the electrical element E. In order to generate such a resonance, the inductance L1 and capacitance C1 are disposed and connected in parallel to the piezoelectric driving apparatus Cd seen from the power source S, and an LC resonance circuit is formed. On the other hand, in the acoustic element A, an RLC series resonance circuit is formed.
In addition, the capacitance Cl also has a function to make DC current not flow in the entire circuit. The reason is that, since the power source S prevents polarization inversion of the piezoelectric driving apparatus Cd, an AC voltage having a bias is generated such that the potential is not inverted whether the potential is positive or negative. That is, this is because the power source S produces the pulsating voltage where a DC offset is added to an AC voltage.
In this manner, the circuit shown in
In the configuration shown in
In this manner, since it is possible to integrally provide at least a portion of the capacitor or inductor required for the driving circuit with the piezoelectric driving apparatus, it is possible to improve the overall space utilization efficiency more than in a case of providing the above separately. In addition, integrally providing at least a portion of the capacitor or the inductor with the piezoelectric driving apparatus makes it possible to reduce the length of the wiring and to reduce the loss of energy due to the wiring resistance.
Furthermore, as in the piezoelectric driving apparatus described above, in a case where a capacitor where a piezoelectric body (a dielectric body) which is the same as the piezoelectric body which forms the piezoelectric element is set as a spacer is integrally provided in the piezoelectric driving apparatus, the temperature characteristics of the piezoelectric element of the piezoelectric driving apparatus and the temperature characteristics of the capacitor are the same. Then, the piezoelectric element and the capacitor are provided at spatially close positions. Therefore, the piezoelectric element and the capacitor can change in the same manner in terms of the electrical characteristics with respect to changes in the temperature of the environment where the piezoelectric driving apparatus is placed. Due to this, for example, when the resonance frequency changes due to a change in environmental temperature, it is possible to reduce the adjustment range of the frequency using the driving circuit. Accordingly, the stability with respect to changes in the environmental temperature is good and it is possible to adjust the resonance frequency more easily.
In the motor 507, the portion of the piezoelectric driving apparatus 500 corresponding to the fixing portion 512a of the vibrating unit 501 is fixed by a screw 522 passing through the hole 511. As shown in
The protrusions 518 are members which come in contact with the rotor 508 and transmit the movement of the vibrating plate 510 to the rotor 508. It is possible for the rotor (driven body) 508 which comes in contact with the protrusions 518 to rotate in a predetermined rotation direction by applying an appropriate pulsating voltage to the piezoelectric driving apparatus 500 to produce ultrasonic vibration. In addition, changing the size and phase of the pulsating voltage for each piezoelectric element makes it possible to rotate the rotor 508 in contact with the protrusion 518 in the opposite direction.
Since the motor 507 of the third embodiment includes the piezoelectric driving apparatus 500 described above, the piezoelectric driving apparatus 500 is not easily damaged and has high reliability.
The piezoelectric driving apparatus according to the invention is able to apply a large force with respect to a driven body by using resonance, and is applicable to various types of apparatuses. The piezoelectric driving apparatus according to the invention can be used as a driving apparatus in various types of devices such as, for example, robots (also including electronic component transporting apparatuses (IC handlers)), dosing pump, clock calendar feeding apparatuses, and paper feeding mechanisms for printing apparatuses. Description will be given below of a typical embodiment. Below, as the piezoelectric driving apparatus according to the invention, description will be given of an apparatus which includes the piezoelectric driving apparatus 100.
Each of the joint portions 2020 has a built-in piezoelectric driving apparatus 100 and it is possible to rotate or bend the joint portions 2020 at an arbitrary angle using the piezoelectric driving apparatuses 100. A robot hand 2000 is connected at the tip of the arm 2010. The robot hand 2000 is provided with a pair of grip portions 2003. The piezoelectric driving apparatus 100 is also built into the robot hand 2000 and it is possible to grip objects by opening and closing a grip portion 2003 using the piezoelectric driving apparatus 100. In addition, the piezoelectric driving apparatus 100 is also provided between the robot hand 2000 and the arm 2010 and it is possible to rotate the robot hand 2000 with respect to the arm 2010 using the piezoelectric driving apparatus 100.
Here, in addition to the piezoelectric driving apparatus 100, a power line for supplying power to various devices such as a force sensor or a gyro sensor, a signal line for transmitting a signal, or the like is included in the interior of the joint portion 2020 of the wrist or the robot hand 2000 and an extremely large amount of wiring is necessary. Accordingly, arranging the wiring in the interior of the joint portion 2020 or the robot hand 2000 was extremely difficult. However, since the piezoelectric driving apparatus 100 can reduce the driving current more than a normal electric motor, it is possible to arrange the wiring even in a small space such as the joint portion 2020 (in particular, the joint portion at the tip of the arm 2010) or the robot hand 2000.
The reservoir 2211 is an accommodating portion which accommodates a liquid which is a transportation object. The tube 2212 is a tube for transporting the liquid fed from the reservoir 2211. The contact portion 20 of the piezoelectric driving apparatus 100 is provided in a state of being pressed against the side surface of the rotor 2222 and the piezoelectric driving apparatus 100 rotates and drives the rotor 2222. The rotational force of the rotor 2222 is transmitted to the cam 2202 via the reduction transmission mechanism 2223. The fingers 2213 to 2219 are members for closing the tube 2212. When the cam 2202 is rotated, the fingers 2213 to 2219 are pressed outward in the radial direction in order by a protrusion 2202A of the cam 2202. The fingers 2213 to 2219 close the tube 2212 in order from the upstream side (the reservoir 2211 side) in the transport direction. Due to this, the liquid in the tube 2212 is sequentially transported to the downstream side. In this manner, it is possible to transport extremely small amounts with high accuracy and it is also possible to realize the small feeding pump 2200.
Here, the arrangement of each member is not limited to that illustrated. In addition, a configuration may be adopted in which a ball or the like provided in the rotor 2222 closes the tube 2212 without providing members such as the fingers. The feeding pump 2200 described above can be used in a dispensing device which administers medicine such as insulin to humans, or the like. Here, since it is possible to reduce the driving current more than in a normal electric motor by using the piezoelectric driving apparatus 100, it is possible to suppress the power consumption of the dispensing device. Accordingly, in a case where the dispensing device is driven by a battery, the invention is particularly effective.
The embodiments and modification examples described above are examples and the invention is not limited thereto. For example, it is also possible to appropriately combine each embodiment and each modification example.
The invention includes configurations substantially the same as the configurations described in the embodiments (for example, configurations where the functions, methods, and results are the same, or configurations where the object and effects are the same). In addition, the invention includes configurations obtained by replacing the portions not essential to the configurations described in the embodiments. In addition, the invention includes configurations which exhibit the same effects as the configurations described in the embodiments or configurations which are able to achieve the same object. In addition, the invention includes configurations where a known technique is added to the configuration described in the embodiments.
The entire disclosure of Japanese Patent Application No. 2015-190750, filed Sep. 29, 2015, No. 2015-222938, filed Nov. 13, 2015 and No. 2015-222939, filed Nov. 13, 2015, is expressly incorporated by reference herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-190750 | Sep 2015 | JP | national |
| 2015-222938 | Nov 2015 | JP | national |
| 2015-222939 | Nov 2015 | JP | national |
