JP5760172B2 - Power generation device and power generation module using the same - Google Patents

Description

  The present invention relates to a power generation device and a power generation module using the power generation device.

Power generation devices that convert vibration energy into electrical energy using piezoelectric materials (piezoelectric vibration power generation devices) are attracting attention in fields such as energy harvesting and are being researched and developed in various places (for example, non-power generation devices). Patent Documents 1 and 2). Here, Non-Patent Document 1 describes PZT (Pb (Zr, Ti) O ₃ ) as a piezoelectric material, and Non-Patent Document 2 describes PZT and aluminum nitride (AlN) as piezoelectric materials. ) Is described.

  By the way, power generation devices can be classified according to the form of a piezoelectric body (thin film type, bulk type). Here, Non-Patent Document 1 describes a thin-film power generation device manufactured using a micromachining technique. Non-Patent Document 2 describes a bulk-type power generation device.

  As shown in FIG. 14, the power generation device disclosed in Non-Patent Document 1 includes a device substrate 301 formed using a silicon substrate 300. The device substrate 301 is provided at a support portion 311 having a rectangular frame shape, a cantilever portion (beam) 312 that is disposed inside the support portion 311 and is swingably supported by the support portion 311, and a tip portion of the cantilever portion 312. The weight portion 313 is provided. In addition, the power generation device includes a power generation unit 320 that is provided in the cantilever unit 312 in the device substrate 301 and generates an AC voltage according to the vibration of the cantilever unit 312.

  The power generation unit 320 includes a lower electrode 322, a piezoelectric film 321 formed on the opposite side of the lower electrode 322 to the cantilever part 312 side, and an upper electrode 323 formed on the opposite side of the piezoelectric film 321 to the lower electrode 322 side. It consists of and. Here, in the power generation unit 320, the lower electrode 322 is formed of a Pt film, the piezoelectric film 321 is formed of an AlN thin film or a PZT thin film, and the upper electrode 323 is formed of an Al film.

  In addition, the power generation device is formed using the first glass substrate 400, the first cover substrate 401 to which the support portion 311 is fixed on one surface side (the upper surface side in FIG. 14) of the device substrate 301, and the second cover substrate 401 A second cover substrate 501 formed using a glass substrate 500 and having a support portion 311 fixed on the other surface side (lower surface side in FIG. 14) of the device substrate 301.

  Displacement spaces 426 and 526 for the movable portions are formed between the cover substrates 401 and 501 and the movable portion including the cantilever portion 312 and the weight portion 313 of the device substrate 301.

  In addition, the power generation device described in Non-Patent Document 2 includes a support portion, a cantilever portion that is swingably supported by the support portion, and a weight portion that is provided at a tip portion of the cantilever portion opposite to the support portion side. The cantilever part is formed of a bimorph piezoelectric element in which two layers of piezoelectric bodies are bonded together.

  Non-Patent Document 2 describes FIG. 15 as an equivalent circuit model of a system using a power generation device.

Here, in this equivalent circuit model, an equivalent circuit of the power generation device equivalent inductance L _m corresponding to the mass or inertia of the weight, and the equivalent resistance Rb which corresponds to the mechanical damping, which corresponds to a mechanical stiffness It is represented using an equivalent capacitor C _k , an equivalent stress σ _in generated when external vibration is applied, an equivalent turns ratio n of the transformer, and a capacitor C _b formed by a power generation unit. In addition, this equivalent circuit model includes a full-wave rectification circuit in which four diodes D1, D2, D3, and D4 are bridge-connected to full-wave rectify the output voltage v of the power generation device, and an output terminal of the full-wave rectification circuit. A power storage capacitor C _st connected between them is described.

R. van Schaijk, et al, “Piezoelectric AlN energy harvesters for wireless autonomous transducer solutions”, IEEE SENSORS 2008 Conference, 2008, p.45-48 S Roundy and P K Wright, “A piezoelectric vibration based generator for wireless electronics”, Smart Materials and Structures 13,2004, p1131-1142

  By the way, the thin-film power generation device such as the power generation device described in Non-Patent Document 1 can be downsized as compared with the bulk-type power generation device described in Non-Patent Document 2, while the output voltage can be reduced. Therefore, it is desired to increase the output voltage. Moreover, when constructing | generating the power generation module which outputs DC voltage using the power generation device described in the nonpatent literature 1, the structure which connected the full wave rectifier circuit between the output terminals of a power generation device like the nonpatent literature 2, and In this case, it is also desired to increase the output voltage.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a power generation device capable of achieving high output while achieving downsizing and a power generation module using the power generation device.

A power generation device according to the present invention includes a device substrate having a support portion, a cantilever portion that is swingably supported by the support portion, and a weight portion provided at a tip portion of the cantilever portion opposite to the support portion side. , and a power generating unit for generating an AC voltage in response to vibration of the cantilever portion is provided et been pre Symbol cantilever portion, the power generating unit includes a piezoelectric body formed on one surface in the thickness direction of the cantilever portion, A pair of electrodes formed on a side surface of the piezoelectric body on the weight portion side and a side surface of the piezoelectric body on the support portion side and facing each other, and one electrode of the pair of electrodes There are formed on the support portion, and wherein the other electrode is formed on the weight section, a direction in which the polarization direction of the previous SL piezoelectric body toward from one to the other of said side surfaces To do.

  In this power generation device, it is preferable that a pair of polarization processing electrodes is provided on the opposite side of the piezoelectric body from the cantilever part side.

  In this power generation device, each of the polarization processing electrodes is formed in a comb shape, each comb bone portion is opposed to each other, and the comb tooth portion of one of the polarization processing electrodes and the comb of the other polarization processing electrode. It is preferable that the tooth portions are alternately arranged in the direction along the direction connecting the both side surfaces.

  The power generation module of the present invention includes the power generation device and a circuit board on which the power generation device is mounted, and the circuit board is provided with a double-wave voltage doubler rectifier circuit that doubles the output voltage of the power generation device. It is characterized by.

  In the power generation device of the present invention, it is possible to increase the output while reducing the size.

  In the power generation module of the present invention, it is possible to increase the output while reducing the size.

The power generation device of Embodiment 1 is shown, (a) is a schematic plan view, (b) is A-A 'schematic sectional drawing of (a). It is explanatory drawing of the manufacturing method of the electric power generating device of Embodiment 1. FIG. It is explanatory drawing of the manufacturing method of the electric power generating device of Embodiment 1. FIG. The electric power generation device of the reference form 1 is shown, (a) is a schematic plan view, (b) is A-A 'schematic sectional drawing of (a). It is a waveform diagram of the output voltage of the power generation device of Reference Form 1. 2 is a schematic plan view of the power generation module according to Embodiment 1. FIG. 1 is a schematic circuit diagram of a power generation module according to Embodiment 1. FIG. It is a circuit diagram of the electric power generation module of reference form 1. It is a circuit diagram of the state which connected the load to the power generation module of reference form 1. FIG. 6 is a schematic exploded perspective view of a power generation device according to a second embodiment. 10 is a schematic cross-sectional view of a main part of a first cover substrate in the power generation device of Embodiment 2. FIG. The electric power generation device of Embodiment 3 is shown, (a) is a schematic plan view, (b) is A-A 'schematic sectional drawing of (a). The electric power generation device of Embodiment 3 is shown, (a) is a schematic plan view, (b) is A-A 'schematic sectional drawing of (a). It is a schematic sectional drawing of the power generation device of a prior art example. It is an equivalent circuit model figure of the electric power generation device of another prior art example.

(Embodiment 1)
Hereinafter, the electric power generation device of this embodiment is demonstrated based on FIG.

  The power generation device 1 includes a support substrate 11, a cantilever portion 12 that is swingably supported by the support portion 11, and a weight substrate 13 that is provided at the tip of the cantilever portion 12 opposite to the support portion 11 side. 10 and a power generation unit 20 that is provided in the cantilever part 12 and generates an alternating voltage in response to vibration of the cantilever part 12.

  The device substrate 10 is formed using the substrate 10a. As the substrate 10a, a single crystal silicon substrate whose one surface is a (100) plane is used, but not limited to this, a polycrystalline silicon substrate may be used. In the device substrate 10, the substrate 10a and the power generation unit 20 are electrically insulated by a first insulating film 10b made of a silicon oxide film formed on the one surface side of the substrate 10a. In the device substrate 10, a second insulating film 10c made of a silicon oxide film is formed on the other surface side of the substrate 10a. However, the second insulating film 10c is not necessarily provided. The substrate 10a is not limited to a silicon substrate, and for example, an SOI (Silicon on Insulator) substrate, a magnesium oxide (MgO) substrate, a metal substrate, a glass substrate, a polymer substrate, or the like may be used. When an insulating substrate such as an MgO substrate, a glass substrate, or a polymer substrate is used as the substrate 10a, it is not necessary to provide the first insulating film 10b.

  In the device substrate 10, the support portion 11 is formed in a frame shape (here, a rectangular frame shape), and the cantilever portion 12 and the weight portion 13 are disposed inside the support portion 11. Here, the device substrate 10 is provided with a U-shaped slit 10d in plan view surrounding the movable portion composed of the cantilever portion 12 and the weight portion 13, so that the device substrate 10 has a portion other than the connection portion with the support portion 11 in the cantilever portion 12. This portion is spatially separated from the support portion 11. Note that the support portion 11 may be in a shape that can swingably support the cantilever portion 12 and does not necessarily have a frame shape.

  The power generation unit 20 is formed on the one surface side of the device substrate 10. Here, the power generation unit 20 includes a piezoelectric body 21 formed on one surface in the thickness direction of the cantilever section 12, an electrode 23 formed on the side surface of the piezoelectric body 21 on the weight section 13 side, and a support section on the piezoelectric body 21. And an electrode 22 formed on the side surface on the 11th side. In short, the power generation unit 20 includes a pair of electrodes 22 and 23 that face each other. The power generation unit 20 has a direction in which the polarization of the piezoelectric body 21 is directed from one of the two side surfaces to the other (the arrow in FIG. 1B represents the direction of polarization). Accordingly, the polarity of the capacitor formed by the power generation unit 20 is positive for the right electrode 23 and negative for the left electrode 22 in FIG. Note that the polarity of this capacitor may be reversed.

  In the power generation device 1, since the power generation unit 20 is configured by a piezoelectric conversion unit having an electrode 22, a piezoelectric body 21, and an electrode 23, the piezoelectric body 21 of the power generation unit 20 receives stress due to the vibration of the cantilever unit 12. 22 and the electrode 23 are biased, and an AC voltage is generated in the power generation unit 20. In short, the power generation device 1 of the present embodiment is a piezoelectric vibration power generation device in which the power generation unit 20 generates power using the piezoelectric effect of the piezoelectric material.

PZT is adopted as the piezoelectric material of the piezoelectric body 21, but is not limited thereto, and for example, PZT-PMN (Pb (Mn, Nb) O ₃ ) or PZT added with other impurities may be used. In addition, the piezoelectric material is AlN, ZnO, KNN (K _0.5 Na _0.5 NbO ₃ ), KN (KNbO ₃ ), NN (NaNbO ₃ ), KNN, impurities (for example, Li, Nb, Ta, Sb, Cu, etc.) The thing etc. which added may be sufficient.

  As a material for each of the electrodes 22 and 23, Au is adopted, but is not limited thereto, and may be Pt, Ir, Al, Mo, or the like. Each of the electrodes 22 and 23 may be composed of, for example, a first conductive film stacked on each side surface of the piezoelectric body 21 and a second conductive film stacked on the first conductive film. In this case, for example, Au, Pt, Ir, Al, Mo or the like is adopted as the material of the second conductive film, and Ti or the like is adopted as the material of the first conductive film, whereby each of the electrodes 22 and 23 is used. It is possible to improve the adhesion between the piezoelectric member 21 and the piezoelectric member 21. The material of the first conductive film may be appropriately changed according to the material of the piezoelectric body 21 and the second conductive film, and is not limited to Ti, and, for example, Cr, TiN, TaN, or the like may be employed.

  In the power generation device 1 of the present embodiment, regarding the thickness in the thickness direction of the cantilever portion 12, the thickness of the piezoelectric body 21 and the thickness of each of the electrodes 22 and 23 are set to the same value, but need not necessarily be the same value. . As an example, the thickness of the piezoelectric body 21 may be set to 600 nm, and the thicknesses of both the electrodes 22 and 23 may be set to 600 nm. However, these numerical values are not particularly limited.

The power generation device 1 may have a structure in which a buffer layer is provided between the device substrate 10 and the piezoelectric body 21. By providing the buffer layer, the crystallinity of the piezoelectric body 21 can be improved. It becomes possible to improve the piezoelectric performance. The material of the buffer layer may be appropriately selected according to the piezoelectric material of the piezoelectric body 21. When the piezoelectric material of the piezoelectric body 21 is PZT, for example, (Pb, La) TiO ₃ , PbTiO ₃ , MgO, or the like is used. It is preferable to adopt. Further, the buffer layer may be constituted by a laminated film of a Pt film and a SrRuO ₃ film, for example.

  On the one surface side of the device substrate 10, a first pad electrically connected to one electrode 22 of the power generation unit 20 (left electrode 22 in FIG. 1A) via a first wiring 26a. 27a and a second pad 27b electrically connected to the other electrode 23 (the right electrode 23 in FIG. 1A) via the second wiring 26b are formed. Here, the pads 27 a and 27 b are formed in the device substrate 10 at portions corresponding to the support portions 11. In the power generation device 1 of this embodiment, the first pad 27a and the second pad 27b constitute output terminals T1 and T1, respectively.

  As a material of each wiring 26a, 26b and each pad 27a, 27b, Au is adopted, but is not limited thereto, and for example, Pt, Ir, Al, Mo, or the like may be used. Each of the wirings 26a and 26b includes, for example, a first conductive film stacked on the first insulating film 10b on the one surface side of the substrate 10a and a second conductive film stacked on the first conductive film. It may be configured. In this case, for example, Au, Pt, Ir, Al, Mo, or the like is adopted as the material of the second conductive film, and Ti or the like is adopted as the material of the first conductive film, whereby the wirings 26a, 26b. In addition, the adhesion between the pads 27a and 27b and the first insulating film 10b can be improved. Note that the material of the first conductive film may be appropriately changed according to the material of the base (the first insulating film 10b or the substrate 10a made of the above-described insulating substrate) and the second conductive film. For example, Cr, TiN, TaN, etc. can be adopted.

  In the power generation device of this embodiment, the materials of the wirings 26a and 26b and the pads 27a and 27b are the same as the materials of the electrodes 22 and 23, and the wirings 26a and 26b and the pads 27a and 27b The electrodes 22 and 23 are formed simultaneously. Therefore, it is possible to reduce the cost by simplifying the manufacturing process as compared with the case where the materials of the wirings 26a and 26b, the pads 27a and 27b, and the electrodes 22 and 23 are different.

  Hereinafter, the manufacturing method of the electric power generation device 1 of this embodiment is demonstrated based on FIG. 2, FIG. 2 and 3, the upper stage is a schematic plan view and the lower stage is a schematic cross-sectional view.

  First, an insulating film forming step of forming insulating films 10b and 10c made of a silicon oxide film on the one surface side and the other surface side of the substrate 10a made of a silicon substrate is performed. Thereafter, a piezoelectric film forming step of forming a piezoelectric film (for example, a PZT thin film) 21a serving as a basis of the piezoelectric body 21 on the entire surface on the one surface side of the substrate 10a is performed, whereby the structure shown in FIG. obtain. As a method of forming the insulating films 10b and 10c in the insulating film forming step, for example, a thermal oxidation method may be employed, but not limited thereto, a CVD method or the like may be employed. As a method of forming the piezoelectric film 21a in the above-described piezoelectric film forming step, the sputtering method is adopted, but not limited thereto, for example, a CVD method or a sol-gel method may be adopted. In addition, you may provide the buffer layer formation process which forms the above-mentioned buffer layer before a piezoelectric film formation process. Further, when the above-described insulating substrate is used as the substrate 10a, the insulating film forming step is unnecessary.

  After the above-described piezoelectric film forming step, the structure shown in FIG. 2B is obtained by performing the piezoelectric film patterning step of forming the piezoelectric body 21 composed of a part of the piezoelectric film 21a by patterning the piezoelectric film 21a. . In the piezoelectric film patterning step, the piezoelectric film 21a is patterned using a photolithography technique and an etching technique.

  After the above-described piezoelectric film patterning step, a conductor layer forming step of forming a conductor layer 29 serving as the basis of each electrode 22, 23, each wiring 26a, 26b, and each pad 27a, 27b on the entire surface on the one surface side of the substrate 10a. To obtain the structure shown in FIG. In the conductor layer forming step, the conductor layer 29 may be formed by, for example, a sputtering method, a CVD method, a vapor deposition method, or the like. In addition, although Au is employ | adopted as a material of the conductor layer 29, not only this but Pt, Ir, Al, Mo, etc. may be sufficient. In the conductor layer forming step, a laminated film of the above-described first conductive film and second conductive film may be formed as the conductor layer 29.

  After the above-described conductor layer forming step, the conductor layer 29 is patterned to perform the conductor layer patterning step of forming the electrodes 22, 23, the wirings 26a, 26b, and the pads 27a, 27b. ) Is obtained. In the conductor layer patterning step, the conductor layer 29 is patterned using a photolithography technique and an etching technique.

  After the conductor layer patterning step, a polarization processing step is performed in which a portion sandwiched between the electrodes 22 and 23 in the piezoelectric body 21 is polarized (polling processing) by energizing between the pads 27a and 27b. After that, a groove is formed by etching a portion other than the cantilever portion 12, the weight portion 13 and the support portion 11 (a region where the slit 10d is to be formed) corresponding to the thickness of the cantilever portion 12 from the one surface side of the substrate 10a. A groove forming step is performed. In the groove forming step, the groove is formed using a photolithography technique, an etching technique, and the like. After the above groove forming step, the cantilever is combined with the weight portion 13 and the support portion 11 by etching a portion other than the weight portion 13 and the support portion 11 (a region where the slit 10d is to be formed) from the other surface side of the substrate 10a. By performing the cantilever part forming step for forming the part 12, the power generation device 1 having the structure shown in FIG. 3B is obtained. In the cantilever part forming step, the cantilever part 12 is formed together with the weight part 13 and the support part 11 by using a photolithographic technique and an etching technique.

  Here, the power generation device 1 including the device substrate 10 and the power generation unit 20 is divided into individual power generation devices 1 by performing the dicing process after performing the cantilever part formation process at the wafer level. I have to.

  By the way, the inventors of the present application made a prototype of the power generation device 1 ′ of Reference Mode 1 shown in FIG. 4 before manufacturing the power generation device 1 of the present embodiment. Note that, in the power generation device 1 ′ of the reference form, the same components as those of the power generation device 1 of the present embodiment are denoted by the same reference numerals.

  The power generation device 1 ′ of the reference form 1 has substantially the same basic configuration as that of the first embodiment, and the electrode 22, the piezoelectric body 21, and the electrode 23 configuring the power generation unit 20 are stacked in the thickness direction of the cantilever unit 12. Differences are made. Further, in the power generation device 1 ′ of Reference Embodiment 1, the insulating layer 125 having the opening 125 a that defines the area of the contact portion of the electrode 23 with the piezoelectric body 21 is formed on the one surface side of the substrate 10 a.

  However, when the resonance frequency of the power generation device 1 ′ is set to 750 Hz, the open-circuit voltage of the power generation device 1 ′ of the reference form 1 is obtained only as an AC voltage having a maximum value of about 0.07V as shown in FIG. I couldn't. The open-circuit voltage of the power generation device 1 ′ becomes a sinusoidal AC voltage in accordance with the vibration of the piezoelectric body 21.

  Further, as a result of earnest research, the inventors of the present application have determined an equivalent circuit model in a state in which both pads 27a and 27b are opened for the power generation device 1 ′ of Reference Embodiment 1, an AC current source, and a capacitive component of the power generation unit 20. The output characteristic (open circuit voltage) of the equivalent circuit model matches the output characteristic (open circuit voltage) of the experimental result by representing the parallel circuit of the capacitor configured by the resistor R0 composed of the resistance component of the power generation unit 20 I got the knowledge to do. Here, the frequency of the alternating current source is the same as the resonance frequency of the power generation device 1 ′ when the frequency of the external vibration matches the resonance frequency of the power generation device 1 ′. The external vibration includes, for example, various environmental vibrations such as a vibration generated by an operating FA device, a vibration generated by traveling of the vehicle, and a vibration generated by walking of a person.

  In the power generation device 1 of the present embodiment, the power generation unit 20 includes a piezoelectric body 21 formed on one surface side in the thickness direction of the cantilever unit 12, a side surface on the support unit 11 side in the piezoelectric body 21, and a weight portion 13 in the piezoelectric body 21. A pair of electrodes 22 and 23 that are formed on the side surface and are opposed to each other, and the polarization direction of the piezoelectric body 21 is directed from one of the two side surfaces to the other. In the power generation device 1 of the present embodiment described above, it becomes possible to increase the open-circuit voltage of the power generation unit 20 without changing the chip size as compared with the power generation device 1 ′ of the reference mode 1. It is also possible to increase the output.

  Next, the power generation module 2 using the above-described power generation device 1 will be described with reference to FIGS. 6 and 7.

  The power generation module 2 includes a power generation device 1 and a circuit board 3 on which the power generation device 1 is mounted. The circuit board 3 is provided with a double-wave voltage doubler rectifier circuit 4 (see FIG. 7) that doubles the output voltage of the power generation device 1. A printed circuit board is used as the circuit board 3. In addition, an opening (not shown) for securing a displacement space of the movable part composed of the cantilever part 12 and the weight part 13 of the power generation device 1 is provided in the circuit board 3 in the thickness direction of the circuit board 3. Has been. In addition, the circuit board 3 may form a recess for securing the displacement space instead of the opening.

  In the double voltage rectifier circuit 4, a series circuit of two diodes D1 and D3 and a series circuit of two capacitors C2 and C4 are connected in parallel. In short, in the double wave voltage doubler rectifier circuit, two diodes D1, D3 and two capacitors C2, C4 are bridge-connected. Here, in the power generation module 2, the first pad 27a of the power generation device 1 is connected to the connection point of the two diodes D1 and D3 in the series circuit of the two diodes D1 and D3. 27b is connected to the connection point of both capacitors C2 and C4 in a series circuit C2 and C4 of two capacitors. As each of the diodes D1 and D3, a surface mount type diode is used. Further, as each of the capacitors C2 and C4, a surface mount type capacitor is used. Therefore, the power generation module 2 can be made thinner than the case where the diodes D1 and D3 and the capacitors C2 and C4 are provided with leads that are mounted by inserting leads into the through holes of the circuit board 3. Is possible.

  Further, the power generation module 2 is provided between the output terminal T2 connected to the high potential end of the series circuit of the two capacitors C2 and C4 and the output terminal T2 connected to the low potential end (that is, the two capacitors C2). , C4 series circuit), a load (not shown) is connected to function as a load power source. For example, an LED (Light Emitting Diode), a sensor, or the like can be used as the load. Note that the operating voltage of the LED is about the band gap energy of the crystal material of the light emitting layer. Therefore, in a red LED having a band gap energy of 2 eV, the operating voltage is about 2V.

  The diode D1 and the diode D3 have the same specifications and have the same characteristics. Note that silicon diodes are used as the diodes D1 and D3, and the forward voltage drop is about 0.6 to 0.7V.

  The capacitors C2 and C4 have the same specifications and have the same characteristics. In addition, although the capacity | capacitance of each capacitor | condenser C2, C4 is set to 10 micro F, this numerical value is an example and is not specifically limited.

  Hereinafter, the operation of the power generation module 2 will be briefly described.

  In the positive half cycle in which the first pad 27a has a higher potential than the second pad 27b with respect to the output voltage of the power generation device 1, the power generation module 2 includes the first pad 27a → the diode D1 → the capacitor C2 → the second. A current flows through the path of the pad 27b, and the capacitor C2 is charged. In addition, the power generation module 2 includes the second pad 27b → the capacitor C4 → the diode D3 → in the negative half cycle in which the first pad 27a has a lower potential than the second pad 27b with respect to the output voltage of the power generation device 1. A current flows through the path of the first pad 27a, and the capacitor C4 is charged. In short, in the double voltage rectifier circuit 4 of the power generation module 2, the capacitors C <b> 2 and C <b> 4 are charged every half cycle of the voltage waveform of the output voltage of the power generation device 1. Therefore, the output voltage of the power generation module 2 is approximately twice the peak value of the output voltage of the power generation device 1.

  By the way, the inventors of the present application made a prototype of the power generation module 2 ′ of the reference form 1 shown in FIG. 8 before manufacturing the power generation module 2 of the present embodiment.

  The power generation module 2 ′ of the reference form 1 includes a full-wave rectifier circuit 5 connected between the power generation device 1 ′ of the reference form 1 described above and the first pad 27a and the second pad 27b of the power generation device 1 ′. And a storage capacitor Cst connected between the output terminals of the full-wave rectifier circuit 5. The full-wave rectifier circuit 5 is a diode bridge in which four diodes D1, D2, D3, and D4 are bridge-connected, and has a function of full-wave rectifying the output voltage Vout (see FIG. 9) of the power generation device 1 ′. ing. In FIG. 9, a load 7 connected between both ends of the storage capacitor Cst is shown.

  However, in the power generation module 2 'according to the first embodiment, the charging voltage Vst charged in the capacitor Cst is saturated at a value considerably lower than the peak value of the output voltage Vout of the power generation device 1'. The cause of this is that in the positive half cycle in which the first pad 27a is at a higher potential than the second pad 27b with respect to the output voltage Vout of the power generation device 1 ′, voltage loss (forward order) occurs in the two diodes D1 and D2. In the negative half cycle in which the first pad 27a is at a lower potential than the second pad 27b with respect to the output voltage Vout of the power generation device 1 ′, voltage loss occurs in the two diodes D3 and D4. (Forward voltage drop) occurs. For this reason, when an LED having an operating voltage of 2 V is used as the load 7, the LED that is the load 7 may not be lit.

  On the other hand, the power generation module 2 of this embodiment includes a double-wave voltage doubler rectification circuit 4 instead of the full-wave rectification circuit 5 in the power generation module 2 ′ of the reference mode 1. In the power generation module 2, the charging voltage Vsto charged in the series circuit of the capacitors C2 and C4 can be increased as compared with the charging voltage Vst of the power generation module 2 'according to the first embodiment. For this reason, even when an LED having an operating voltage of 2 V is used as the load described above, the LED that is the load can be turned on.

Thus, in calling Denmo Joule 2 of the present embodiment, it is possible while achieving downsizing achieve higher output.

(Embodiment 2)
Hereinafter, the power generation device 1 of the present embodiment will be described with reference to FIGS. 10 and 11.

  The basic configuration of the power generation device 1 of the present embodiment is substantially the same as that of the first embodiment, and other than the device substrate 10 formed using the substrate 10a (hereinafter referred to as the first substrate 10a) and the power generation unit 20. The difference is that a first cover substrate 30 fixed to the support portion 11 is provided on one surface side of the device substrate 10 (upper surface side in FIG. 10). Further, the power generation device 1 of the present embodiment is different in that the power generation device 1 includes a second cover substrate 40 fixed to the support portion 11 on the other surface side (the lower surface side in FIG. 10) of the device substrate 10. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

The first cover substrate 30 is formed using the second substrate 30a. Here, a silicon substrate is used as the second substrate 30a. The first cover substrate 30, on one surface of the device substrate 1 side 0, recess for forming a displacement space of the movable portion composed of the cantilever portion 12 and the weight portion 13. Between the device substrate 10 30b (see FIG. 11) is formed.

  A pair of output electrodes 35 and 35 for outputting an alternating voltage generated in the power generation unit 20 are formed on the other surface side of the first cover substrate 30. Therefore, in the power generation device 1 of the present embodiment, the pair of output electrodes 35 and 35 instead of the pair of pads 27a and 27b constitute a pair of output terminals T1 and T1. As shown in FIG. 11, the first cover substrate 30 includes output electrodes 35 and 35 and communication electrodes 34 and 34 formed on the one surface side of the first cover substrate 30. One cover substrate 30 is electrically connected through through-hole wirings 33, 33 penetrating in the thickness direction. Here, in the first cover substrate 30, one connection electrode 34 is joined and electrically connected to the first pad 27 a of the device substrate 10, and the other connection electrode 34 is connected to the second pad of the device substrate 10. The pad 27b is joined and electrically connected. In the present embodiment, the output electrodes 35 and 35 and the connection electrodes 34 and 34 are formed of a laminated film of a Ti film and an Au film, but these materials are not particularly limited. Moreover, although Cu is adopted as the material of each through-hole wiring 33, 33, it is not limited thereto, and for example, Ni, Al, etc. may be adopted.

  The first cover substrate 30 includes an insulating film 32 made of a silicon oxide film for preventing a short circuit between the two output electrodes 35, 35, and the one surface side and the other surface of the first cover substrate 30. The through-hole wirings 33 and 33 are formed across the inner peripheral surface of the through-holes 31 and 31 formed inside. The first cover substrate 30 is not limited to a silicon substrate, and may be formed using an insulating substrate such as a glass substrate. In this case, the insulating film 32 need not be provided. Here, as the glass material of the glass substrate, it is preferable to use a glass material having a small difference in linear expansion coefficient from Si, such as borosilicate glass. Further, the power generation device 1 does not include the connection electrodes 34 and 34, the through-hole wirings 33 and 33, and the output electrodes 35 and 35 on the first cover substrate 30. Alternatively, the pads 27a and 27b on the one surface side of the device substrate 10 may be exposed. In this case, as in the first embodiment, the first pad 27a and the second pad 27b are the output terminals T1 and T1, respectively.

  The second cover substrate 40 is formed using the third substrate 40a. Here, a silicon substrate is used as the third substrate 40a. On one surface of the second cover substrate 40 on the device substrate 10 side, a recess 40 b for forming a displacement space of the movable part between the device substrate 10 and the second cover substrate 40 is formed. Note that the third substrate 40a is not limited to a silicon substrate, and an insulating substrate such as a glass substrate may be used. Here, as the glass material of the glass substrate, it is preferable to use a glass material having a small difference in linear expansion coefficient from Si, such as borosilicate glass.

  The device substrate 10 has a first bonding metal layer 28 for bonding to the first cover substrate 30 on the one surface side of the first substrate 10a. In contrast, the first cover substrate 30 is formed with a second bonding metal layer (not shown) bonded to the first bonding metal layer 28. Here, as the material of the first bonding metal layer 28, the same material as that of each of the pads 27a and 27b is adopted, and the first bonding metal layer 28 is on the one surface side of the first substrate 10a. The pad 27a and 27b are formed to have the same thickness.

  The device substrate 10 and the cover substrates 30 and 40 are bonded by the room temperature bonding method, but not limited to the room temperature bonding method, for example, heated at a predetermined temperature higher than the room temperature (for example, about 50 ° C. to 100 ° C.). However, the bonding may be performed by a direct bonding method in which an appropriate load is applied, a resin bonding method using an epoxy resin, an anodic bonding method, or the like. In the resin bonding method, if a room temperature curable resin adhesive (for example, a two-part room temperature curable epoxy resin adhesive, a one part room temperature curable epoxy resin adhesive) is used, a thermosetting resin adhesive is used. Compared to the case of using a thermosetting epoxy resin adhesive (for example), the bonding temperature can be lowered.

In the power generation device 1 of the present embodiment described above, as in the first embodiment, it is possible to increase the output while reducing the size. Further, in the power generation device 1 of the present embodiment, for example, the first bonding metal layer 28 is formed over the entire outer periphery of the frame-shaped support portion 11 and the first cover substrate 30 is configured as described above. The second bonding metal layer may be formed over the entire outer periphery of the first cover substrate 30. In this case, the first bonding metal layer 28 and the second bonding metal layer are bonded over the entire circumference, and further, the device substrate 10 and the peripheral portion of the second cover substrate 40 are formed over the entire circumference. By joining over, it becomes possible to make the space enclosed by the support part 11 and each cover substrate 30 and 40 into an airtight space. The airtight space can be an inert gas atmosphere or a vacuum atmosphere.

  Further, instead of the power generation device 1 in the power generation module 2 (see FIGS. 6 and 7) described in the first embodiment, the power generation device 1 according to the present embodiment may be used. It is possible to increase the output while aiming. In this case, it is not necessary to form the opening and the recess in the circuit board 3 (see FIG. 6).

(Embodiment 3)
The power generation device of this embodiment is demonstrated based on FIG.

  The basic configuration of the power generation device 1 of the present embodiment is substantially the same as that of the first embodiment, and a pair of polarization processing electrodes 24 and 25 are provided on the opposite side of the piezoelectric body 21 from the cantilever 12 side. Is different. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  In the pair of polarization processing electrodes 24 and 25, one polarization processing electrode 24 is formed on one end on the electrode 22 side of the piezoelectric body 21, and the other polarization processing electrode 25 is the electrode of the piezoelectric body 21. It is formed on the other end which becomes the 23 side. Here, each of the polarization processing electrodes 24 and 25 is formed in a belt-like shape with the width direction of the cantilever portion 12 as a longitudinal direction.

  As a material for each of the polarization processing electrodes 24 and 25, Au is adopted, but is not limited thereto, and may be Pt, Ir, Al, Mo, or the like. Each of the polarization processing electrodes 24 and 25 includes, for example, a first conductive film stacked on the opposite side of the piezoelectric body 21 from the cantilever portion 12 side, and a second conductive film stacked on the first conductive film. You may comprise. In this case, for example, Au, Pt, Ir, Al, Mo or the like is adopted as the material of the second conductive film, and Ti or the like is adopted as the material of the first conductive film. It becomes possible to improve the adhesiveness between 24 and 25 and the piezoelectric body 21. Note that the material of the first conductive film may be changed as appropriate according to the material of the piezoelectric body 21, and is not limited to Ti, and for example, Cr, TiN, TaN, or the like may be employed.

  The method of manufacturing the power generation device 1 of the present embodiment is substantially the same as the manufacturing method described in the first embodiment. After the conductor layer patterning step, for example, the polarization processing electrodes 24 and 25 are formed using a lift-off method or the like. The electrode forming step to be formed may be performed, and then the polarization treatment may be performed by applying a voltage between the polarization treatment electrodes 24 and 25. As a method for forming the electrodes 24 and 25 for the polarization treatment, a lift-off method may be used, or a thin film forming technology such as a sputtering method, a CVD method, or a vapor deposition method, and an etching technology may be used.

  In the power generation device 1 of the present embodiment described above, as in the first embodiment, it is possible to increase the output while reducing the size. In the power generation device 1 of the present embodiment, the first cover substrate 30 and the second cover substrate 40 may be provided as in the second embodiment.

Further, instead of the power generation device 1 in the power generation module 2 (see FIGS. 6 and 7) described in the first embodiment, the power generation device 1 according to the present embodiment may be used. It is possible to increase the output while aiming. Further, in this case, after the power generation device 1, the capacitors C2 and C4, and the diodes D1 and D3 are mounted on the circuit board 3 and the power generation device 1 and the double wave voltage rectifier circuit 4 are electrically connected. However , the polarization process can be performed without affecting the double wave voltage doubler rectifier circuit 4 and the like.

(Embodiment 4)
The power generation device of this embodiment is demonstrated based on FIG.

  The basic configuration of the power generation device 1 of the present embodiment is substantially the same as that of the third embodiment, and the shapes of the pair of polarization processing electrodes 24 and 25 are different. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 3, and description is abbreviate | omitted.

  Each of the polarization processing electrodes 24 and 25 is formed in a comb shape, and the respective comb bone portions 24a and 25a face each other. The plurality of comb teeth portions 24b of one polarization processing electrode 24 and the other polarization processing electrode. A plurality of comb tooth portions 25b of 25 are alternately arranged in the direction along the direction connecting the both side surfaces of the piezoelectric body 21 where the electrodes 22 and 23 are formed. In short, in the power generation device 1 of the present embodiment, each comb tooth portion 24b of the one polarization processing electrode 24 is inserted into the comb groove of the other polarization processing electrode 25, and the one polarization processing electrode 24 is. The comb tooth portion 24b and the comb tooth portion 25b of the other polarization processing electrode 25 are separated from each other in a direction along the direction connecting the both side surfaces. In each of the polarization processing electrodes 24 and 25, the comb tooth portions 24 b and 25 b are orthogonal to the direction connecting the support portion 11, the cantilever portion 12, and the weight portion 13 of the device substrate 10 in plan view.

  In the power generation device 1 of the present embodiment, compared to the power generation device 1 of the third embodiment, the voltage applied between the pair of polarization processing electrodes 24 and 25 in the polarization processing step is reduced (for example, from about 1000 V to about 100 V). Can be reduced). As a result, it is possible to use an inexpensive voltage source for applying a voltage between the pair of polarization processing electrodes 24 and 25 in the polarization processing step, and to reduce the manufacturing cost.

  In the power generation device 1 of the present embodiment described above, as in the first embodiment, it is possible to increase the output while reducing the size. In the power generation device 1 of the present embodiment, the first cover substrate 30 and the second cover substrate 40 may be provided as in the second embodiment.

  Further, instead of the power generation device 1 in the power generation module 2 (see FIGS. 6 and 7) described in the first embodiment, the power generation device 1 according to the present embodiment may be used. It is possible to increase the output while aiming.

DESCRIPTION OF SYMBOLS 1 Power generation device 3 Circuit board 4 Double wave voltage doubler rectifier circuit 10 Device board 11 Support part 12 Cantilever part 13 Weight part 20 Power generation part 21 Piezoelectric body 22 Electrode 23 Electrode 24 Polarization processing electrode 24a Comb bone part 24b Comb tooth part 25 Polarization Processing electrode 25a Comb bone portion 25b Comb tooth portion

Claims (4)

A device substrate having a support portion, a cantilever portion swingably supported by the support portion, and a weight portion provided at a tip portion opposite to the support portion side of the cantilever portion; and a device substrate provided in the cantilever portion. is a power generation unit for generating an AC voltage in response to vibration of the front Symbol cantilever portion, the power generating unit includes a piezoelectric body formed on one surface in the thickness direction of the cantilever portion, the in the piezoelectric weight portion A pair of electrodes formed on the side surface on the side and the side surface on the support portion side of the piezoelectric body and facing each other, and one electrode of the pair of electrodes is formed on the support portion is, the power generation device and the other electrode, characterized in that said is formed on the spindle portion, a direction in which the polarization direction of the previous SL piezoelectric body toward from one to the other of said side surfaces.   The power generation device according to claim 1, wherein a pair of electrodes for polarization treatment is provided on the side opposite to the cantilever part side of the piezoelectric body.   Each of the polarization processing electrodes is formed in a comb shape, and each comb bone portion is opposed to each other, and the comb tooth portion of one of the polarization processing electrodes and the comb tooth portion of the other polarization processing electrode, The power generation device according to claim 2, wherein the power generation devices are arranged alternately and spaced apart in a direction along a direction connecting the both side surfaces.   Both waves which comprise the electric power generation device of any one of Claim 1 thru | or 3, and the circuit board by which the said electric power generation device was mounted, and carry out double voltage rectification of the output voltage of the said electric power generation device on the said circuit board. A power generation module comprising a voltage doubler rectifier circuit.

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