WO2014188649A1

WO2014188649A1 - Power generating apparatus

Info

Publication number: WO2014188649A1
Application number: PCT/JP2014/002019
Authority: WO
Inventors: 純矢小川; 貴司中川
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2013-05-23
Filing date: 2014-04-09
Publication date: 2014-11-27
Also published as: JP2014230426A

Abstract

A power generating apparatus (1a)is provided with: a frame-shaped supporting section (11); a cantilever section (12), which is disposed inside of the supporting section, and which has one end thereof, i.e., a fixed end (12a), fixed to the supporting section, and the other end thereof as a free end (12b); a piezoelectric transducer section (14), which is provided on the cantilever section, and which generates an alternating current voltage corresponding to vibration of the cantilever section; and a first flow channel (15a) configured from a space formed between the supporting section and the cantilever section. The cantilever section is warped such that the free end is positioned outside of a space (19) surrounded by means of an inner surface (11b) of the supporting section, and a second flow channel (15b) that penetrates the cantilever section in the thickness direction thereof is formed in the cantilever section.

Description

Power generator

The present invention relates to a power generation device, and more particularly to a power generation device that generates power using fluid excitation vibration.

In recent years, power generation devices that convert vibration energy into electrical energy have attracted attention in fields such as energy harvesting.

As this type of power generation device, for example, a power generation device 201 configured as shown in FIGS. 12A, 12B and 12C has been proposed (for example, Japanese Patent Application Publication No. 2012-97673 (hereinafter referred to as “Document 1”)). .

The power generation device 201 includes a base 211 and a lead 213 to which the piezoelectric element 214 is fixed.

The base 211 has a plate 215 on which a rectangular window 212 is formed. As shown in FIG. 12A, the size of the window 212 is slightly larger than the lead 213 facing the window 212, and a slight gap through which the gas F passes is formed between the edge of the window 212 and the lead 213. Has been.

The lead 213 is flexible so that it can bend and vibrate in the thickness direction. For example, the lead 213 is a flexible printed board formed of FRP (Fiber Reinforced Plastics) or the like, and has an output terminal (not shown) of the piezoelectric element 214. The lead 213 is positioned so that one end 231 is fixed to the upper surface of the plate 215 and the other end 232 faces the window 212 so that the window 212 can freely enter and exit.

Further, as shown in FIG. 12B, the lead 213 is slightly inclined with respect to the upper surface of the plate 215 so that the end 232 is located outside the window 212 (the side into which the gas F flows) ( Is up). Here, the distance t from the end 232 of the lead 213 to the window 212 (the upper surface of the plate 215) in a state of not vibrating is set according to the strength of the wind to be used. In Document 1, for example, in order to vibrate the lead 213 even when the wind force is weak, the distance t may be set to the thickness of the end 232 of the lead 213, or to extract a large energy when the wind force is strong. Describes that the distance t may be increased.

The piezoelectric element 214 is a bimorph piezoelectric element, and is fixed to both front and back surfaces of the lead 213 as shown in FIGS. 12A and 12C. Document 1 describes that the piezoelectric element 214 may be a unimorph piezoelectric element fixed to one of the front and back surfaces of the lead 213.

Further, as a power generation apparatus that converts vibration energy into electrical energy, for example, a power generation device 300 having a configuration shown in FIGS. 13A and 13B has been proposed (for example, Japanese Patent Application Publication No. 2011-91318).

The power generation device 300 includes a cantilever-forming substrate 320 having a frame part (support part) 321 and a cantilever part 322, and a piezoelectric conversion part 324 that generates an alternating voltage in response to vibration of the cantilever part 322. The piezoelectric conversion portion 324 is formed on the cantilever portion 322 on one surface side of the cantilever forming substrate 320. Further, the cantilever forming substrate 320 is integrally provided with a weight portion 323 at the tip of the cantilever portion 322.

The frame part 321, the cantilever part 322, and the weight part 323 are formed using an element formation substrate 420. As the element formation substrate 420, an SOI (Silicon on Insulator) substrate having a single crystal silicon layer 420c on a buried oxide film 420b on a support substrate 420a made of a single crystal silicon substrate is used.

The piezoelectric conversion unit 324 includes a lower electrode 324a, a piezoelectric layer 324b, and an upper electrode 324c.

In the above-described power generation apparatus 201, the power generation efficiency is not sufficient, and further improvement is required.

The inventors of the present application considered generating the power generation device 300 with a fluid. That is, the inventors of the present application have considered arranging the power generation device in the flow field and generating the power generation device 300 using the fluid flowing in the flow field.

However, it is difficult for the power generation device 300 to generate power using a fluid.

An object of the present invention is to provide a power generation apparatus that can reduce the critical flow velocity of fluid-excited vibration and can improve power generation efficiency.

The power generation device of the present invention includes a frame-shaped support portion, a cantilever portion that is disposed inside the support portion, one end is fixed to the support portion, and the other end is a free end, and the cantilever portion A piezoelectric converter that is provided and generates an AC voltage in response to vibration of the cantilever part; and a first flow path that is formed by a gap formed between the support part and the cantilever part. The cantilever part is warped so that the free end is located outside the space surrounded by the inner surface of the support part. The cantilever part is formed with a second flow path penetrating in the thickness direction of the cantilever part.

In this power generation device, the second flow path is formed in a shape in which the inner side surface of the support portion in the cantilever portion is opened, and the support portion has the free end of the cantilever portion entering the space. It is preferable that the structural body disposed in the space so as to reduce the cross-sectional area of the second flow path is integrally provided.

In this power generation device, it is preferable that the thickness of the structure in the direction along the thickness direction of the support portion is the same as the thickness of the support portion.

In this power generator, the second flow path is preferably formed so as to divide a part of the cantilever part into a plurality of parts in the width direction of the cantilever part.

In this power generation device, the cantilever portion includes a weight portion on the free end side, and a portion on the fixed end side of the weight portion in the length direction of the cantilever portion is deformed when the cantilever portion vibrates. It is preferable that a strain generating portion that generates strain is formed, the second flow path is formed in the weight portion, and the piezoelectric conversion portion is provided in the strain generating portion.

In this power generation device, it is preferable that the cantilever part also forms the second flow path in the strain generating part.

In this power generation device, it is preferable that the piezoelectric conversion unit includes a plurality of piezoelectric conversion elements, and at least two of the plurality of piezoelectric conversion elements are electrically connected in series.

In the power generation device of the present invention, it is possible to reduce the critical flow velocity of the fluid excitation vibration, and to improve the power generation efficiency.

FIG. 1A is a schematic plan view of the power generator of Embodiment 1. FIG. 1B is a schematic cross-sectional view taken along the line XX of FIG. 1A. FIG. 2 is a schematic cross-sectional view of a first modification of the power generation device according to the first embodiment. FIG. 3 is a schematic plan view of a second modification of the power generation device according to the first embodiment. FIG. 4A is a schematic plan view of the power generation device according to the second embodiment. 4B is a schematic cross-sectional view taken along the line XX of FIG. 4A. FIG. 5 is a schematic perspective view of the power generation apparatus according to the second embodiment. FIG. 6 is a schematic plan view of a first modification of the power generation device according to the second embodiment. FIG. 7A is a schematic plan view of the power generation device of the third embodiment. FIG. 7B is a schematic cross-sectional view taken along the line X1-X1 of FIG. 7A. FIG. 7C is a schematic cross-sectional view taken along the line X2-X2 of FIG. 7A. FIG. 8 is a schematic plan view of a first modification of the power generation device according to the third embodiment. FIG. 9 is a schematic plan view of a second modification of the power generation device according to the third embodiment. FIG. 10 is a schematic plan view of a third modification of the power generation device according to the third embodiment. FIG. 11 is a schematic plan view of a fourth modification of the power generation device according to the third embodiment. FIG. 12A is a schematic plan view of a conventional power generator. 12B is a cross-sectional view taken along the line XX of FIG. 12A. 12C is a YY cross-sectional view of FIG. 12A. FIG. 13A is a schematic plan view of a conventional power generation device. 13B is a schematic cross-sectional view taken along the line XX of FIG. 13A.

(Embodiment 1)
Below, the electric power generating apparatus 1a of this embodiment is demonstrated based on FIG. 1A and 1B.

The power generation device 1a includes a frame-shaped support portion 11, a cantilever portion 12 that is disposed inside the support portion 11, one end is fixed to the support portion 11, and the other end is a free end 12b. The cantilever portion A piezoelectric converter 14 that generates an alternating voltage in response to vibration of the cantilever part 12 and a first flow path 15a that is formed by a gap formed between the support part 11 and the cantilever part 12; I have. The cantilever portion 12 is warped so that the free end 12b is located outside the space 19 surrounded by the inner side surface 11b of the support portion 11. In the cantilever portion 12, a second flow path 15b penetrating in the thickness direction of the cantilever portion 12 is formed. As a result, the power generation device 1a can achieve a reduction in the generation limit flow rate of the fluid excitation vibration, and can improve the power generation efficiency.

The fluid-excited vibration is vibration of the cantilever part 12 generated when the fluid flowing through the flow field passes through the first flow path 15a in a state where the power generation device 1a is disposed in the flow field. This fluid excitation vibration is self-excited vibration. Examples of the fluid include air, gas, a mixed gas of air and gas, and liquid. When the fluid is a gas, examples of the flow field include the inside of an air supply duct of an air conditioner and the inside of an exhaust duct of an air conditioner, but may be other than these.

The generation limit flow velocity of the fluid excitation vibration means a lower limit value of the flow velocity at which the self-excited vibration of the cantilever portion 12 can be generated.

By the way, the inventors of the present application contemplate the present invention by paying attention to the following (1) to (3) relating to the power generation apparatus of the reference embodiment having the same basic configuration as the power generation apparatus 1a and not provided with the second flow path 15b. It came to.

(1) The generation limit flow velocity of the cantilever portion 12 that self-excites and receives fluid is proportional to the square root of the mass per unit length of the cantilever portion 12.

(2) The power generation device includes a first surface 121 side and a second surface 122 side of the cantilever portion 12 that are generated when a fluid passes through a first flow path 15 a provided between the support portion 11 and the cantilever portion 12. Self-excited vibration occurs due to the pressure difference between the cantilever portion 12 and the elasticity of the cantilever portion 12. Therefore, the power generating device can increase the amplitude of the free end 12b of the cantilever part 12 by increasing the cross-sectional area of the first flow path 15a with respect to the area of the cantilever part 12.

(3) In the power generation apparatus, the amount of power generation can be increased by increasing the area of the piezoelectric conversion unit 14.

(1), (2) and (3) are contradictory.

In contrast, the power generation device 1a of the present embodiment includes a first flow path 15a configured by a gap formed between the support portion 11 and the cantilever portion 12, and the cantilever portion 12 has a free end 12b. Is warped so as to be located outside the space 19 surrounded by the inner side surface 11 b of the support portion 11. Further, in the power generation device 1 a, a second flow path 15 b that penetrates the cantilever part 12 in the thickness direction of the cantilever part 12 is formed. Therefore, the power generation device 1a can achieve a reduction in the generation limit flow rate of the fluid excitation vibration, and can improve the power generation efficiency.

Each component of the power generator 1a will be described in detail below.

The power generation device 1a is manufactured using a manufacturing technology of MEMS (micro-electromechanical mechanical systems).

In the power generation device 1 a, a support portion 11 and a cantilever portion 12 are formed from a substrate 10. The power generation device 1 a has a cantilever portion 12 formed on the first surface 101 side in the thickness direction of the substrate 10.

As the substrate 10, an SOI substrate in which a silicon layer 10c is formed on a silicon oxide film (buried oxide film) 10b on a silicon substrate 10a is used. The first surface 101 of the substrate 10 is a (100) surface, but is not limited to this, and may be a (110) surface, for example.

The support portion 11 is formed of a silicon substrate 10a, a silicon oxide film 10b, and a silicon layer 10c among SOI substrates. On the other hand, the cantilever part 12 is formed from the silicon layer 10c of the SOI substrate. Thereby, the cantilever part 12 in the power generation device 1a is thinner than the support part 11 and has flexibility. The cantilever part 12 has elasticity. In short, the cantilever part 12 is supported by the support part 11 so as to be swingable.

In the power generation device 1 a, the substrate 10 and the piezoelectric conversion unit 14 are electrically insulated by a first insulating film 18 a formed on the first surface 101 side of the substrate 10. The first insulating film 18a can be composed of, for example, a silicon oxide film. The power generation device 1 a may include a second insulating film (not shown) made of a silicon oxide film on the second surface 102 side in the thickness direction of the substrate 10. The first insulating film 18a and the second insulating film can be formed by, for example, a thermal oxidation method. The method of forming the first insulating film 18a and the second insulating film is not limited to the thermal oxidation method, and may be, for example, a CVD (Chemical Vapor Deposition) method.

The substrate 10 is not limited to an SOI substrate, and a single crystal silicon substrate, a polycrystalline silicon substrate, a magnesium oxide (MgO) substrate, a metal substrate, a glass substrate, a polymer substrate, or the like can also be used. When the power generation apparatus 1a uses an insulating substrate such as an MgO substrate, a glass substrate, or a polymer substrate as the substrate 10, the first insulating film 18a and the second insulating film are not necessarily provided.

The support portion 11 preferably employs a rectangular frame shape as the frame shape. That is, it is preferable that the support portion 11 has a rectangular outer peripheral shape. Thereby, the power generation device 1a prepares a wafer as a base of the substrate 10 at the time of manufacture, performs a pre-process for forming a large number of power generation devices 1a from the wafer, and separates the individual power generation devices 1a in a post-process. When a simple manufacturing method is employed, the workability of the dicing process can be improved. When the substrate 10 is an SOI substrate, the wafer serving as the basis of the substrate 10 is an SOI wafer.

The support portion 11 preferably has a rectangular outer peripheral shape, but the inner peripheral shape is not limited to a rectangular shape, and may be a polygonal shape other than a rectangular shape, a circular shape, an elliptical shape, or the like. Further, the outer peripheral shape of the support portion 11 may be a shape other than a rectangular shape.

In the power generation device 1a, the cantilever portion 12 is disposed inside the support portion 11 in a plan view. In the power generation device 1a, a slit 10d having a U-shape in plan view surrounding the cantilever portion 12 is formed in the substrate 10, so that a portion other than the fixed end 12a that is a connection portion with the support portion 11 in the cantilever portion 12 is supported. It is separated from the part 11. Thereby, the cantilever part 12 is cantilevered by the support part 11. In the power generation device 1a, the slit 10d constitutes the first flow path 15a.

The piezoelectric conversion unit 14 is provided on the first surface 121 side (the first surface 101 side of the substrate 10) in the thickness direction of the cantilever unit 12. The piezoelectric conversion unit 14 includes a first electrode (lower electrode) 14a provided on the first surface 121 side of the cantilever unit 12, a piezoelectric layer 14b provided on the first electrode 14a, and a piezoelectric layer 14b. And a second electrode (upper electrode) 14c provided. In short, the piezoelectric conversion unit 14 includes a piezoelectric layer 14b and a first electrode 14a and a second electrode 14c facing each other with the piezoelectric layer 14b sandwiched from both sides in the thickness direction.

In the power generation device 1 a, the piezoelectric layer 14 b of the piezoelectric conversion unit 14 receives stress due to the vibration of the cantilever unit 12, and a bias of electric charge occurs between the second electrode 14 c and the first electrode 14 a, and an AC voltage is appear. In short, the power generation device 1a is a vibration type power generation device in which the piezoelectric conversion unit 14 generates power using the piezoelectric effect of the piezoelectric material.

The planar shape of the piezoelectric layer 14b is formed in a rectangular shape. In the piezoelectric converter 14, it is preferable that the outer size of the piezoelectric layer 14b is slightly smaller than the outer size of the first electrode 14a and slightly larger than the outer size of the second electrode 14c. Hereinafter, a region where the first electrode 14a, the piezoelectric layer 14b, and the second electrode 14c overlap in the thickness direction of the cantilever portion 12 is referred to as a piezoelectric conversion region 141. In the piezoelectric conversion unit 14, the piezoelectric conversion region 141 contributes to generation of an alternating voltage. In the power generation device 1 a, the end 141 a on the fixed end 12 a side of the piezoelectric conversion region 141 is aligned with the boundary between the cantilever portion 12 and the support portion 11 in the length direction of the cantilever portion 12. As a result, the power generation device 1a is positioned on the cantilever portion 12 in the length direction of the cantilever portion 12 as compared with the case where the end 141a on the fixed end 12a side of the piezoelectric conversion region 141 is closer to the cantilever portion 12 than the boundary. The area of the existing piezoelectric conversion region 141 can be increased. Thereby, the power generation device 1a can improve the power generation efficiency. Further, the power generation device 1a does not contribute to power generation in the piezoelectric conversion region 141 and has a parasitic capacitance as compared with the case where the end 141a on the fixed end 12a side of the piezoelectric conversion region 141 is closer to the support portion 11 than the boundary. Therefore, it is possible to reduce the portion that is generated and improve the power generation efficiency. The length direction of the cantilever part 12 is a direction along the axis of the cantilever part 12.

The AC voltage generated in the piezoelectric converter 14 is a sinusoidal AC voltage corresponding to the vibration of the piezoelectric layer 14b. Here, it is assumed that the piezoelectric conversion unit 14 of the power generation device 1a generates power using self-excited vibration generated by fluid flowing through the first flow path 15a and the second flow path 15b. The resonance frequency of the power generation device 1a is determined by the structural parameters and the material of the movable part composed of the cantilever part 12 and the piezoelectric conversion part 14.

The power generation device 1 a is provided with a first pad electrode (not shown) and a second pad electrode (not shown) on the first surface 111 side in the thickness direction of the support portion 11. The first surface 111 of the support portion 11 is smoothly continuous with the first surface 121 of the cantilever portion 12 in the vicinity of the fixed end 12 a of the cantilever portion 12. When the power generation device 1a does not include the second insulating film, the second surface 112 in the thickness direction of the support portion 11 and the second surface 102 of the substrate 10 are the same. When the power generation device 1 a includes the second insulating film on the second surface 102 side of the substrate 10, the surface of the second insulating film becomes the second surface 112 of the support portion 11.

The first pad electrode is electrically connected to the first electrode 14a via a first wiring (not shown). The second pad electrode is electrically connected to the second electrode 14c via a second wiring (not shown). The material of the first wiring, the second wiring, the first pad electrode, and the second pad electrode is Au, but is not limited to this. For example, Mo, Al, Pt, Ir, or the like may be used. The materials of the first wiring, the second wiring, the first pad electrode, and the second pad electrode are not limited to the same material, and different materials may be employed. Further, the first wiring, the second wiring, the first pad electrode, and the second pad electrode are not limited to a single layer structure, and may be a multilayer structure of two or more layers.

Further, in the power generation device 1a, an insulating layer (not shown) that prevents a short circuit between the second wiring and the first electrode 14a is provided between the second wiring and the peripheral portion of the first electrode 14a. This insulating layer is formed of a silicon oxide film, but is not limited to a silicon oxide film, and may be formed of, for example, a silicon nitride film.

As the piezoelectric material of the piezoelectric layer 14b, PZT (Pb (Zr, Ti) O ₃ ) is adopted, but not limited to this, for example, PZT-PMN (Pb (Mn, Nb) O ₃ ), PZT added with impurities may also be used. Further, the piezoelectric material may be AlN, ZnO, KNN (K _0.5 Na _0.5 NbO ₃ ), KN (KNbO ₃ ), NN (NaNbO ₃ ), a material obtained by adding impurities to KNN, or the like. Examples of the impurity include Li, Nb, Ta, Sb, and Cu. In the power generation device 1a, the piezoelectric layer 14b is formed of a piezoelectric thin film.

The material of the first electrode 14a is Pt, but is not limited thereto, and may be Au, Al, Ir, or the like, for example. Further, although Au is adopted as the material of the second electrode 14c, it is not limited to this, and for example, Mo, Al, Pt, Ir, or the like may be used.

In the power generation apparatus 1a, the thickness of the first electrode 14a is set to 500 nm, the thickness of the piezoelectric layer 14b is set to 3000 nm, and the thickness of the second electrode 14c is set to 500 nm. is not.

The power generation device 1a may have a structure in which a buffer layer is provided between the substrate 10 and the first electrode 14a. The material of the buffer layer may be appropriately selected according to the piezoelectric material of the piezoelectric layer 14b. When the piezoelectric material of the piezoelectric layer 14b is PZT, for example, SrRuO ₃ , (Pb, La) TiO ₃ , PbTiO ₃ , MgO, LaNiO ₃ or the like is preferably used as the material of the buffer layer 14b. Further, the buffer layer may be constituted by a laminated film of a Pt film and a SrRuO ₃ film, for example. By providing the buffer layer, the power generation device 1a can improve the crystallinity of the piezoelectric layer 14b and improve the power generation efficiency.

In the cantilever portion 12, a second flow path 15b penetrating in the thickness direction of the cantilever portion 12 is formed. The second flow path 15b is formed in a shape in which the inner surface 11b side of the support portion 11 in the cantilever portion 12 is opened. The second flow path 15b is formed on the free end 12b side of the vertical projection region of the piezoelectric conversion unit 14 in the cantilever part 12 in the length direction of the cantilever part 12. The second flow path 15b is preferably formed so as to divide a part of the cantilever part 12 into two in the width direction of the cantilever part 12 (vertical direction in FIG. 1A).

In the power generation device 1a, since the resonance frequency of the cantilever part 12 is defined by the length of the cantilever part 12, the second flow path 15b divides a part of the cantilever part 12 into two in the width direction of the cantilever part 12. By being formed in this way, the vibration of the cantilever part 12 is stabilized, and it becomes possible to improve the power generation efficiency. Here, in the power generation device 1a, the width dimension H1 of the part on one side of the second flow path 15b in the width direction of the cantilever part 12 in the cantilever part 12 is equal to the width dimension H2 of the part on the other side. preferable. Therefore, in the second flow path 15 b, the fluid inflow port 151 in the first surface 121 of the cantilever part 12 and the fluid outflow port 152 in the second surface 122 of the cantilever part 12 are along the length direction of the cantilever part 12. Is preferably formed. In the power generation device 1a, the second flow path 15b is formed so as to divide a part of the cantilever part 12 into two in the width direction of the cantilever part 12. However, the second flow path 15b is not limited to this. The cantilever portion 12 may be formed so that a part of the cantilever portion 12 is divided into three or more in the width direction of the cantilever portion 12. For example, in the power generation device 1a, two second flow paths 15b may be formed so that a part of the cantilever part 12 is divided into three in the width direction of the cantilever part 12. In the power generation device 1a, as the number of parts of the cantilever part 12 divided in the width direction of the cantilever part 12 is larger, the number of the second flow paths 15b increases, the vibration of the cantilever part 12 becomes more stable, and the power generation efficiency is further increased. It is possible to improve.

An example of a manufacturing method for the power generation device 1a will be briefly described below.

In manufacturing the power generation device 1a, first, a substrate 10 made of an SOI substrate is prepared, and then an insulating film forming step is performed. In the insulating film forming step, a first insulating film 18a and a second insulating film made of a silicon oxide film are formed on the first surface 101 side and the second surface 102 side of the substrate 10 by using a thermal oxidation method or the like, respectively. . In the insulating film forming step, the thermal oxidation method is employed as a method for forming the first insulating film 18a and the second insulating film, but the present invention is not limited thereto, and a CVD method or the like may be employed.

After the insulating film forming step, a first conductive layer forming step for forming a first conductive layer serving as a basis of the first electrode 14a and the first wiring on the entire surface of the substrate 10 on the first surface 101 side is performed, Then, a piezoelectric material layer forming step for forming a piezoelectric material layer serving as a basis of the piezoelectric layer 14b is performed. As a method for forming the first conductive layer, a sputtering method is employed. However, the present invention is not limited thereto, and for example, a CVD method, a vapor deposition method, or the like may be employed. As a method of forming the piezoelectric material layer, a sputtering method is employed, but is not limited thereto, and for example, a CVD method or a sol-gel method may be employed.

After the piezoelectric material layer forming step, a first patterning step of patterning the piezoelectric material layer into a predetermined shape of the piezoelectric layer 14b is performed, and subsequently, the first conductive layer is changed to a predetermined shape of the first electrode 14a and the first wiring. A second patterning step for patterning the shape is performed. In the first patterning step, the piezoelectric material layer is patterned using a lithography technique and an etching technique. In the second patterning step, the first conductive layer is patterned using a lithography technique and an etching technique.

After the second patterning step, an insulating layer forming step for forming the insulating layer on the first surface 101 side of the substrate 10 is performed. After the insulating layer forming step, the second conductive layer forming step for forming the second conductive layer serving as the basis of the second electrode 14c and the second wiring on the entire surface on the first surface 101 side of the substrate 10 is performed. A third patterning step of patterning the two conductive layers into a predetermined shape of the second electrode 14c and the second wiring is performed. As a method for forming the second conductive layer, a sputtering method is employed, but is not limited thereto, and for example, a CVD method, a vapor deposition method, or the like may be employed. In the third patterning step, the second conductive layer is patterned using a lithography technique and an etching technique.

After the third patterning step, a third conductive layer forming step for forming a third conductive layer serving as a basis for the first pad electrode and the second pad electrode on the entire surface on the first surface 101 side of the substrate 10 is performed. After the third conductive layer forming step, a fourth patterning step of patterning the third conductive layer into a predetermined shape of the first pad electrode and the second pad electrode is performed. After the fourth patterning step, a portion other than the support portion 11 and the cantilever portion 12 (scheduled formation region of the slit 10d, planned formation region of the second flow path 15b) is first predetermined from the first surface 101 side of the substrate 10. A first groove forming step is performed in which the first groove is formed by etching to a depth. The first predetermined depth is a depth corresponding to the thickness of the cantilever portion 12. In the first groove forming step, the first groove is formed using a lithography technique, an etching technique, and the like. In the first groove forming step, the silicon oxide film 10b is used as an etching stopper layer. After the first groove forming step, a second groove forming step is performed in which a portion other than the support portion 11 is etched from the second surface 102 side of the substrate 10 to a second predetermined depth to form the second groove. In the second groove forming step, the second groove is formed using a lithography technique, an etching technique, or the like. In the second groove forming step, the silicon oxide film 10b is used as an etching stopper layer. After the second groove forming step, power generation is performed by performing a cantilever portion forming step of forming the cantilever portion 12 together with the support portion 11 by etching a portion of the silicon oxide film 10b other than the support portion 11 by etching. Device 1a is obtained. Further, in the above-described cantilever part forming step, the cantilever part 12 is formed together with the support part 11 using a lithography technique, an etching technique, and the like. Each etching in the first groove forming step, the second groove forming step, and the cantilever portion forming step is dry etching using an inductively coupled plasma type dry etching apparatus capable of vertical deep drilling. In the cantilever forming step, the first flow path 15a and the second flow path 15b are formed. In the method for manufacturing the power generation device 1a, when the cantilever portion 12 is formed, the cantilever portion 12 can be warped by, for example, a compressive stress that is an internal stress of the piezoelectric layer 14b.

In manufacturing the power generation device 1a, the process until the cantilever part forming process is completed is performed at the wafer level, and then the dicing process is performed to divide the power generation device 1a into individual power generation devices 1a.

In the method for manufacturing the power generation device 1a, instead of sequentially performing the third conductive layer forming step and the fourth patterning step, the first pad electrode and the second pad electrode may be formed using a lift-off method. In the method for manufacturing the power generation device 1a, instead of sequentially performing the third conductive layer forming step and the fourth patterning step, the first pad electrode and the second pad electrode are formed by vapor deposition using a metal mask or the like. May be.

By the way, as described above, the cantilever portion 12 in the power generation device 1a is warped so that the free end 12b is located outside the space 19 surrounded by the inner side surface 11b of the support portion 11. In short, in the initial state where no external vibration or fluid acts on the cantilever part 12, the free end 12b of the cantilever part 12 is located outside the space 19 on the first surface 111 side of the support part 11 as shown in FIG. 1B. Warped to be located at. Here, the cantilever portion 12 is curved so that the first surface 121 side is a concave curved surface and the second surface 122 side is a convex curved surface. In the power generation device 1a of this embodiment, the free end 12b of the cantilever part 12 is positioned outside the space 19 surrounded by the inner side surface 11b of the support part 11 due to the internal stress of the piezoelectric thin film constituting the piezoelectric layer 14b. The cantilever portion 12 is warped. For example, when the piezoelectric thin film is formed by sputtering or CVD, the internal stress of the piezoelectric thin film can be adjusted by appropriately setting process conditions such as gas pressure and temperature.

The operation of the power generation device 1a of the present embodiment will be described with the following estimation mechanism. Note that the power generation device 1a of the present embodiment is within the scope of the present invention even if the estimation mechanism is different.

In the power generation device 1a of the present embodiment, the direction in which the fluid flows matches the thickness direction of the support portion 11, the first surface 101 side of the substrate 10 is the upstream side of the fluid, and the second surface 102 side of the substrate 10 is the downstream side of the fluid. It is preferable to arrange and use such that In the power generation device 1a, the fluid flowing from the upstream side toward the power generation device 1a has a higher flow velocity when passing through the first flow path 15a and the second flow path 15b, so the second surface 122 of the cantilever part 12 and the support part 11 The pressure in the space 10 f surrounded by the inner side surface 11 b of the inner surface 11 b decreases, and the free end 12 b of the cantilever portion 12 is displaced in a direction approaching the space 19. And in the electric power generating apparatus 1a, when the 1st surface 121 of the cantilever part 12 and the 1st surface 111 of the support part 11 became the same, in the 1st surface 121 side of the cantilever part 12, and the 2nd surface 122 side, The pressure difference is eliminated. The power generation device 1a is assumed to be displaced in a direction in which the free end 12b of the cantilever part 12 returns to the original position due to the elastic force of the cantilever part 12. In the power generation device 1a, it is assumed that the cantilever portion 12 self-excites and the piezoelectric conversion portion 14 generates power by repeating such an operation.

As described above, the power generation device 1a includes the first flow path 15a and the second flow path 15b, and the free end 12b of the cantilever portion 12 is located outside the space 19 surrounded by the inner surface 11b of the support portion 11. Is warping. As a result, the power generation device 1a generates a pressure difference between the first surface 121 side and the second surface 122 side of the cantilever portion 12 that is generated by a fluid flow (airflow) passing through the first flow path 15a and the second flow path 15b. Since the self-excited vibration can be generated by the elasticity of the cantilever portion 12, it is possible to generate power using a fluid.

Further, in the power generation device 1a, the second flow path 15b penetrating in the thickness direction of the cantilever part 12 is formed in the cantilever part 12. As a result, the power generation device 1a can achieve a reduction in the generation limit flow rate of the fluid excitation vibration, and can improve the power generation efficiency.

Hereinafter, a power generation device 1b of a first modification of the power generation device 1a of the present embodiment will be described with reference to FIG. The power generation device 1b of the first modification is different from the power generation device 1a of the first embodiment in that the cantilever portion 12 is warped by a stress control film 119 formed on the first surface 121 side of the cantilever portion 12. A part of the stress control film 119 is also formed on the first surface 111 side of the support portion 11. In addition, about the component similar to the electric power generating apparatus 1a of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The stress control film 119 is formed so as to cover the piezoelectric conversion part 14 on the first surface 121 side of the cantilever part 12. The stress control film 119 is formed of a silicon oxide film, but is not limited thereto, and may be formed of, for example, a silicon nitride film. The stress control film 119 may be formed on the second surface 122 side of the cantilever portion 12.

As with the power generation device 1a of the first embodiment, the power generation device 1b according to the first modification can reduce the generation limit flow velocity of the fluid excitation vibration and can improve the power generation efficiency. Become.

In the power generator 1b of the first modification, the cantilever portion 12 may be warped by the stress acting on the cantilever portion 12 due to the stress control film 119 and the internal stress of the piezoelectric layer 14b that is a piezoelectric thin film. .

Hereinafter, a power generator 1c of a second modification of the power generator 1a of the present embodiment will be described with reference to FIG.

The power generation device 1c of the second modified example is different from the power generation device 1a of the first embodiment in the area where the piezoelectric conversion portion 14 is formed in the cantilever portion 12. In addition, about the component similar to the electric power generating apparatus 1a of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The power generation device 1c of the second modified example is formed so that the piezoelectric conversion unit 14 covers the first surface 121 of the cantilever unit 12 in a planar shape. Covering in a plane means covering substantially the entire surface of the first surface 121 of the cantilever portion 12, but is not limited to covering the entire surface of the first surface 121, and as shown in FIG. It is also possible to cover the entire area slightly narrower than the entire surface. In the second modified example shown in FIG. 3, the piezoelectric conversion portion 14 is disposed in the vicinity of the side edge of the cantilever portion 12 so as to be separated from the side edge of the cantilever portion 12 by a specified distance. The method for manufacturing the power generation device 1c according to the second modification is basically the same as the method for manufacturing the power generation device 1a according to the first embodiment, except that a photomask for patterning the piezoelectric conversion unit 14 is different. The specified distance may be set so that the piezoelectric conversion portion 14 is not etched when the first groove and the second groove are formed in the method for manufacturing the power generation device 1a of the first embodiment.

(Embodiment 2)
Below, the electric power generating apparatus 1d of this embodiment is demonstrated based on FIG. 4A, 4B, and 5. FIG.

The power generation device 1d of the present embodiment is different from the power generation device 1a of the first embodiment in the configuration of the support portion 11. In addition, about the component similar to the electric power generating apparatus 1a of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The support portion 11 of the power generation device 1d includes a structure 11e arranged in the space 19 so that the cross-sectional area of the second flow path 15b is reduced when the free end 12b of the cantilever portion 12 enters the space 19. Is provided. The first surface 11e1 in the thickness direction of the structure 11e (the vertical direction in FIG. 4B) is preferably on the same plane as the first surface 111 of the support portion 11.

Since the power generation device 1d includes the structure 11e, the cross-sectional area of the second flow path 15b when the first surface 121 of the cantilever portion 12 and the first surface 111 of the support portion 11 are flush with each other is obtained. It can be made smaller. As a result, the power generation device 1d can achieve a further lower flow velocity than the generation limit flow velocity of the fluid excitation vibration as compared with the power generation device 1a of the first embodiment.

In the power generation device 1d, the thickness t2 of the structure 11e in the direction along the thickness direction of the support portion 11 is preferably the same as the thickness t1 of the support portion 11. As a result, the power generation device 1d can increase the rigidity of the structure 11e as compared with the case where the thickness t2 of the structure 11e is the same as the thickness of the cantilever part 12, and the structure when the cantilever part 12 vibrates. It becomes possible to suppress the deformation | transformation of the body 11e. Therefore, the power generation device 1d can suppress the vibration energy due to the vibration of the cantilever portion 12 from being lowered due to the deformation of the structure 11e or the vibration of the cantilever portion 12 becoming unstable. In short, the power generation device 1d can further stabilize the vibration of the cantilever portion 12 because the thickness t2 of the structure 11e is the same as the thickness t1 of the support portion 11.

Hereinafter, a power generation device 1e of a first modification of the power generation device 1d of the present embodiment will be described with reference to FIG. In addition, about the component similar to the electric power generating apparatus 1d of Embodiment 2, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The power generation device 1e of the first modification is formed so that the piezoelectric conversion unit 14 covers the first surface 121 of the cantilever unit 12 in a planar shape. Covering in a planar manner means covering substantially the entire first surface 121 of the cantilever portion 12, but is not limited to covering the entire surface of the first surface 121, and as shown in FIG. It is also possible to cover the entire area slightly narrower than the entire surface. In the first modification shown in FIG. 6, the piezoelectric conversion unit 14 is arranged in the vicinity of the side edge of the cantilever unit 12 so as to be separated from the side edge of the cantilever unit 12 by a specified distance. The method for manufacturing the power generation device 1e according to the first modification is basically the same as the method for manufacturing the power generation device 1a of the first embodiment, and the photomask and the like for patterning the piezoelectric conversion unit 14 are different. The specified distance may be set so that the piezoelectric conversion portion 14 is not etched when the first groove and the second groove are formed in the method for manufacturing the power generation device 1a of the first embodiment.

(Embodiment 3)
Below, the electric power generating apparatus 1f of this embodiment is demonstrated based on FIG. 7A, 7B, and 7C.

The power generating device 1f of the present embodiment is different from the power generating device 1d of the second embodiment in the configuration of the cantilever portion 12 and the like. In addition, about the component similar to the electric power generating apparatus 1d of Embodiment 2, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The cantilever part 12 of the power generation device 1f includes a weight part 23 on the free end 12b side. Further, the cantilever portion 12 of the power generation device 1f is deformed and distorted in the length direction of the cantilever portion 12 when the portion of the cantilever portion 12 on the fixed end 12a side of the weight portion 23 is deformed when the cantilever portion 12 vibrates. The generated strain generating portion 12c is configured. In the power generation device 1f, the second flow path 15b is formed in the weight part 23, and the piezoelectric conversion part 14 is provided in the strain generating part 12c.

Since the power generation device 1 f includes the weight portion 23, the power generation device 1 f can increase the inertial force when the cantilever portion 12 vibrates compared to the case where the weight portion 23 is not provided, and the amplitude of the cantilever portion 12. Can be increased. In addition, since the power generation device 1 f includes the weight portion 23 in the cantilever portion 12, when the cantilever portion 12 vibrates, it is possible to intensively generate strain in the strain generating portion 12 c and the piezoelectric conversion portion 14. Thus, it is possible to improve the power generation efficiency. In addition, the power generation device 1 f can reduce the resonance frequency of the cantilever portion 12 because the cantilever portion 12 includes the weight portion 23. In addition, since the power generation device 1 f has the second flow path 15 b formed in the weight portion 23, it is possible to further reduce the flow limit for generating the fluid excitation vibration.

Hereinafter, a power generator 1g of a first modification of the power generator 1f of the present embodiment will be described with reference to FIG. In addition, about the component similar to the electric power generating apparatus 1f of Embodiment 3, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The power generator 1g of the first modification is different only in that the structure 11e of the power generator 1f of the present embodiment is not provided. In short, the power generation device 1g of the first modification is different only in that the weight portion 23 is provided on the cantilever portion 12 in the power generation device 1a of the first embodiment.

Therefore, the power generation device 1g according to the first modification can further improve the power generation efficiency and further reduce the flow velocity at which the fluid excitation vibration is generated, compared to the power generation device 1a of the first embodiment. .

Hereinafter, a power generation device 1h of a second modification of the power generation device 1f of the present embodiment will be described with reference to FIG. In addition, about the component similar to the electric power generating apparatus 1f of Embodiment 3, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The power generator 1h of the second modification is different from the power generator 1f of the third embodiment in that the second flow path 15b is also formed in the strain generating portion 12c of the cantilever portion 12. For this reason, in the power generation device 1h of the second modification, the piezoelectric conversion unit 14 is divided into two piezoelectric conversion elements 140. The piezoelectric conversion element 140 includes a first electrode 14a, a piezoelectric layer 14b, and a second electrode 14c, like the piezoelectric conversion unit 14. In the piezoelectric conversion unit 14 of the power generation device 1h, it is preferable that the two piezoelectric conversion elements 140 are connected in series by a third wiring (not shown) provided on the first surface 111 side of the support unit 11. Thus, the power generation device 1h can increase the output voltage. In this case, the power generation device 1h includes a pad electrode (third pad electrode) electrically connected to one end of the series circuit of the two piezoelectric conversion elements 140 on the first surface 111 side of the support portion 11, and the other end. What is necessary is just to provide it with the pad electrode (4th pad electrode) electrically connected.

Further, the power generation device 1h according to the second modified example supports the structure 11e corresponding to each of the second flow path 15b provided in the weight portion 23 and the second flow path 15b provided in the strain generating portion 12c of the cantilever portion 12. 11 is integrally provided. As a result, the power generation device 1h can further reduce the flow velocity of the generation limit flow velocity of the fluid excitation vibration.

Hereinafter, a power generation device 1i of a third modification of the power generation device 1f of the present embodiment will be described with reference to FIG. In addition, about the component similar to the electric power generating apparatus 1h of a 2nd modification, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The power generator 1i of the third modification has a longer overall length of the second flow path 15b in the length direction of the cantilever part 12 than the power generator 1h of the second modification, and the strain generating part 12c and the weight part 23 are The point where one second flow path 15b is formed across the power generation apparatus 1h of the second modification is different. As a result, the power generation device 1i can further reduce the critical flow velocity of the fluid excitation vibration, similarly to the power generation device 1h of the second modification.

Hereinafter, a power generator 1j of a fourth modification of the power generator 1f of the present embodiment will be described with reference to FIG. In addition, about the component similar to the electric power generating apparatus 1h of a 2nd modification, the same code | symbol is attached | subjected and description is abbreviate | omitted.

In the power generation device 1j of the fourth modification example, the piezoelectric conversion unit 14 is divided into eight piezoelectric conversion elements 140. On the first surface 121 of the cantilever part 12, the piezoelectric conversion elements are provided on both sides in the width direction of the cantilever part 12. The point where four 140 are arranged is different from the power generator 1h of the second modification.

In the piezoelectric conversion unit 14 of the power generation device 1j, for example, it is preferable that all of the eight piezoelectric conversion elements 140 are connected in series. As a result, the power generation device 1j can increase the output voltage. The power generator 1j includes a first series circuit in which four piezoelectric conversion elements 140 arranged on one side of the second flow path 15b in the width direction of the cantilever portion 12 are connected in series, and the other side of the second flow path 15b. A second series circuit in which the four piezoelectric transducer elements 140 arranged in the series are connected in series may be connected in parallel.

The power generation device 1j does not limit the number of piezoelectric conversion elements 140. The piezoelectric conversion unit 14 includes a plurality of piezoelectric conversion elements 140, and at least two of the plurality of piezoelectric conversion elements 140 are electrically connected in series. It only has to be. As a result, the power generation device 1j can increase the output voltage.

A configuration in which the piezoelectric conversion unit 14 includes a plurality of piezoelectric conversion elements 140 and at least two of the plurality of piezoelectric conversion elements 140 are electrically connected in series may be employed in the first and second embodiments.

In Embodiments 1 to 3, etc., the configuration manufactured using the MEMS manufacturing technology has been described. However, the present invention is not limited to this. For example, each component may be separately formed and assembled. In the configuration manufactured using the MEMS manufacturing technology, it is possible to reduce the size as compared with a configuration in which each component is formed and assembled separately.

The configuration of the present invention has been described based on Embodiments 1 to 3 and the like. However, the present invention is not limited to the configurations of Embodiments 1 to 3 and the like, for example, partial configurations of Embodiments 1 to 3 and the like. These may be combined as appropriate. In addition, the materials, numerical values, and the like described in the first to third embodiments are merely preferable examples, and are not intended to be limiting. Furthermore, the present invention can be appropriately modified in configuration without departing from the scope of its technical idea.

Claims

A frame-shaped support portion; a cantilever portion which is disposed inside the support portion and has one end fixed to the support portion and the other end is a free end; and vibration of the cantilever portion provided in the cantilever portion And a first flow path configured by a gap formed between the support portion and the cantilever portion.
The cantilever part is warped so that the free end is located outside the space surrounded by the inner surface of the support part, and the cantilever part has a second flow path penetrating in the thickness direction of the cantilever part. Formed,
A power generator characterized by that.
The second flow path is formed in a shape in which the inner side surface of the support portion in the cantilever portion is opened,
The support portion is integrally provided with a structure disposed in the space so as to reduce a cross-sectional area of the second flow path when the free end of the cantilever portion enters the space. ,
The power generator according to claim 1.
The thickness of the structure in the direction along the thickness direction of the support portion is the same as the thickness of the support portion.
The power generator according to claim 2.
The second flow path is formed so as to divide a part of the cantilever part into a plurality in the width direction of the cantilever part.
The power generator according to any one of claims 1 to 3.
The cantilever portion includes a weight portion on the free end side, and a portion on the fixed end side of the weight portion in the length direction of the cantilever portion is deformed and generates distortion when the cantilever portion vibrates. A strain generating portion is formed, and the second flow path is formed in the weight portion,
The piezoelectric conversion unit is provided in the strain generating unit,
The power generator according to any one of claims 1 to 4, wherein the power generator is provided.
The cantilever part has the second flow path formed also in the strain generating part.
The power generator according to claim 5.
The piezoelectric conversion unit includes a plurality of piezoelectric conversion elements, and at least two of the plurality of piezoelectric conversion elements are electrically connected in series.
The power generation device according to claim 1, wherein the power generation device is a power generation device.