JP5237705B2 - Power generation device - Google Patents

Description

  The present invention relates to a vibration power generation device that converts vibration energy into electrical energy.

  Conventionally, as one type of MEMS (micro electro mechanical systems) devices, power generation devices that convert vibration energy caused by arbitrary vibrations such as car vibrations and vibrations caused by human movements into electrical energy have been researched and developed in various places. (For example, refer nonpatent literature 1).

  Here, as shown in FIG. 11, the power generation device disclosed in Non-Patent Document 1 includes a base substrate 10 ′ and two comb shapes supported by the base substrate 10 ′ on one surface side of the base substrate 10 ′. Fixed electrodes 24 ', 24' and an anchor portion (not shown) via a support spring portion 22 'disposed between the two fixed electrodes 24', 24 'and spaced from the one surface of the base substrate 10'. ) Supported by a vibrator 23 ′, and an electret 30 ′ formed on a portion of the base substrate 10 ′ facing the movable electrode 25 ′. Note that the above-described power generation device is designed such that the rigidity of the support spring portion 22 ′ is low.

In the power generation device described above, the variable capacitor 26 ′ having the fixed electrode 24 ′ and the movable electrode 25 ′ as electrodes is formed, so that the vibrator 23 ′ has two fixed portions along the one surface of the base substrate 10 ′. By vibrating in the direction in which the electrodes 24 ′ and 24 ′ are arranged side by side (the left-right direction in FIG. 11B) (the white arrow in FIG. 11A indicates the vibration direction of the vibrator 23 ′). The distance between the fixed electrode 24 ′ and the movable electrode 25 ′ and the facing area change, and the capacitance of the variable capacitor 26 ′ changes. Therefore, if the load resistor R is connected between both ends of the series circuit of the variable capacitor 26 ′ and the electret 30 ′, which is a voltage applying means for applying a voltage to the variable capacitor 26 ′, the variable capacitor 26 ′. The electric charge moves in accordance with the change in the electrostatic capacity and a current is generated. Therefore, the vibration energy of the mover 23 ′ generated by the vibration of the vibrator 23 ′ can be converted into electric energy. Here, in order to increase the energy conversion efficiency of the power generation device described above, the amount of change in the capacitance of the variable capacitor 26 ′ may be increased.
T.Sterken, etal, “AN ELECTRET-BASEDELECTROSTATIC μ-GENERATOR”, TRANSDUCERS '03, The 12th International Conference on Solid State Sensors, Actuators and Microsystems, Boston, June 8-12,2003, p.1291-1294

  However, in the power generation device having the configuration shown in FIG. 11, in order to realize a resonance frequency close to the frequency in the low frequency region (for example, about 10 to 500 Hz) existing in the environment, the rigidity of the support spring portion 22 ′ is reduced. It is necessary to reduce the width of the support spring portion 22 ′, reduce the thickness, and increase the total length. Therefore, the displacement of the vibrator 23 ′ increases, and the vibration space of the vibrator 23 ′ increases. It gets bigger. Here, in the power generation device having the configuration shown in FIG. 11, the resonance frequency decreases as the rigidity of the support spring portion 22 ′ decreases, whereas the resonance frequency increases as the mass of the oscillator 23 ′ decreases. Since the planar size of 23 ′ cannot be reduced and the occupied area including the movable range of the support spring portion 22 ′ and the vibrator 23 ′ is increased, the planar size of the entire device is increased. In the power generation device described above, it is conceivable to increase the amount of change in the capacitance of the variable capacitor 26 ′ when the vibrator 23 ′ vibrates by increasing the capacitance of the variable capacitor 26 ′. If the distance between the movable electrode 25 ′ and the fixed electrode 24 ′ (hereinafter referred to as the interelectrode distance) is shortened, the capacitance of the variable capacitor 26 ′ can be increased, but if the distance between the electrodes is too short. The pull-in phenomenon is triggered.

  This invention is made | formed in view of the said reason, The objective is to provide the electric power generation device which can be reduced in plane size.

The invention of claim 1 includes a base substrate and the base over scan a frame portion fixed to one surface of the substrate, the frame portion vibrator inner odor Te are arranged spaced apart from the base over the scan board When a pair of support spring portions said being arranged in a manner sandwiching the vibration Doko inside the frame portions connecting the Doko vibration the said frame portion, the fixed electrode provided on the frame portion and a variable capacitance capacitor configured with the movable electrode provided on the vibration Doko and, and a voltage applying means for applying a voltage to the variable - capacitance capacitor, the supporting lifting spring portion, the frame portion the vibration Doko consists torsion spring capable torsional deformation so as to be swingable against, the fixed electrode is formed in plan view a comb shape, the movable electrode has a plurality of fixed comb of the fixed electrode A plurality of movable comb teeth facing the teeth; The applying means is made of an electret, and the electret is formed in a portion facing the comb bone portion of the fixed electrode on the one surface side of the base substrate, and the frame portion is the comb bone portion of the fixed electrode A recess is formed in a portion that also serves as a gap, and a gap is formed between the comb portion of the fixed electrode and the electret, and an electrode terminal electrically connected to the movable electrode and the electret A series circuit of the variable capacitor and the electret is connected between electrically connected electrode terminals .

According to the invention, the supporting lifting spring portion, wherein the vibration element against the frame portion is made of a torsion spring capable of torsional deformation so that the swingable, said supporting lifting spring portion and said compared with a configuration such as to vibrate in the direction in which mover is along said one surface of said base over scan substrate, to reduce the occupied area including the movable range of the supporting lifting spring portion and the friendly Doko Therefore, the planar size can be reduced .
According to the invention, the fixed electrode is formed in a comb shape in plan view, and the movable electrode has a plurality of movable comb teeth facing the plurality of fixed comb teeth of the fixed electrode. Since the capacitance of the variable capacitor can be increased as compared with the case where the fixed comb tooth piece and the movable comb tooth piece are not formed, the capacitance of the variable capacitor during vibration of the vibrator Can be increased, and energy conversion efficiency can be improved.
In addition, according to the present invention, since the voltage applying means is composed of electrets, the planar size can be reduced as compared with the case where a piezoelectric conversion element or a secondary battery is used as the voltage applying means.

Another invention of the present application is directed to a base substrate, a frame portion fixed to one surface side of the base substrate, a vibrator disposed away from the base substrate inside the frame portion, and the frame portion. A pair of support springs that are arranged inside the vibrator and connect the frame part and the vibrator, a fixed electrode provided on the frame part, and a movable electrode provided on the vibrator. And a voltage applying means for applying a voltage to the variable capacitor, and the support spring portion is twisted and deformed so that the vibrator can swing with respect to the frame portion. consists capable torsion spring, before Symbol fixed electrode is formed in plan view a comb shape, the movable electrode to have a plurality of movable comb-tooth segments facing the plurality of fixed comb-tooth segments of the fixed electrode And butterflies.

According to another aspect of the invention, the support spring portion is a torsion spring that can be torsionally deformed so that the vibrator can swing with respect to the frame portion. Compared to a configuration that vibrates in the direction along the one surface of the base substrate, the occupied area including the movable range of the support spring portion and the mover can be reduced, and the planar size can be reduced. It becomes possible. Furthermore, according to the further invention, since it is possible to increase the capacitance of the variable capacitor as compared with the case where the solid Teikushi tooth segments and the friendly Dokushi tooth segments are not formed, The amount of change in capacitance of the variable capacitor during vibration of the vibrator can be increased, and energy conversion efficiency can be improved.

According to a second aspect of the present invention, in the first aspect of the present invention, the variable capacitor is at least one of both sides in a direction orthogonal to a direction connecting the two support spring portions in a plan view from the one surface side of the base substrate. It is formed in these.

  According to this invention, the amount of change in the capacitance of the variable capacitor during vibration of the vibrator can be increased, and the energy conversion efficiency can be improved.

According to a third aspect of the present invention, in the second aspect of the present invention, the variable capacitor is formed on both sides in a direction orthogonal to a direction connecting the two support spring portions in a plan view from the one surface side of the base substrate. It is characterized by.

  According to this invention, the electrostatic attractive force generated between the movable electrode and the fixed electrode can be canceled on both sides in the direction orthogonal to the direction connecting the two support springs, and the movable electrode is fixed. Pull-in that contacts the electrode by electrostatic attraction can be suppressed.

Another invention of the present application is directed to a base substrate, a frame portion fixed to one surface side of the base substrate, a vibrator disposed away from the base substrate inside the frame portion, A pair of support springs that are arranged inside the vibrator and connect the frame part and the vibrator, a fixed electrode provided on the frame part, and a movable electrode provided on the vibrator. And a voltage applying means for applying a voltage to the variable capacitor, and the support spring portion is twisted and deformed so that the vibrator can swing with respect to the frame portion. consists capable torsion spring, before Symbol voltage applying means is characterized by comprising the electret.

According to another aspect of the invention, the support spring portion is a torsion spring that can be torsionally deformed so that the vibrator can swing with respect to the frame portion. Compared to a configuration that vibrates in the direction along the one surface of the base substrate, the occupied area including the movable range of the support spring portion and the mover can be reduced, and the planar size can be reduced. It becomes possible. Further , according to the other invention, since the voltage applying means is made of an electret, the planar size can be reduced as compared with the case where a piezoelectric conversion element or a secondary battery is used as the voltage applying means.

  In the invention of claim 1, there is an effect that the planar size can be reduced.

(Embodiment 1)
Hereinafter, the power generation device of the present embodiment will be described with reference to FIG.

  The power generation device of the present embodiment includes a rectangular plate-shaped base substrate 10, a frame portion 21 fixed to one surface side of the base substrate 10, and a rectangular shape that is disposed apart from the base substrate 10 inside the frame portion 21. A plate-like vibrator 23, a pair of support spring parts 22, 22 that are arranged so as to sandwich the vibrator 23 inside the frame part 21 and connect the frame part 21 and the vibrator 23, and the frame part 21. The variable capacitor 26 includes a fixed electrode 24 and a movable electrode 25 provided on the vibrator 23, and an electret 30 that applies a voltage to the variable capacitor 26. In the present embodiment, the electret 30 constitutes a voltage applying means for applying a voltage to the variable capacitor 26. However, the voltage applying means is not limited to the electret 30, but for example, a piezoelectric conversion element or a secondary battery. Etc.

  The frame portion 21, the vibrator 23, and the support spring portions 22 and 22 are formed using a single silicon substrate 20 a, and the frame portion 21 includes a plurality of (for example, epoxy resins) made of a bonding resin (for example, epoxy resin). In the illustrated example, the base substrate 10 is bonded to the one surface side via six bonding layers 41. Here, the frame part 21 is formed in a U-shape in plan view and is arranged in such a manner that the front end surfaces of both leg pieces face each other, and both legs of the two frame piece parts 21a and 21a. Two support springs 22, 22 disposed between the tip surfaces of the pieces and connected at one end to the outer surface of the vibrator 23 are integrally connected to the inner surface. It is comprised by the anchor parts 21b and 21b. In short, a slit 21c is formed between each anchor part 21b, 21b and each frame piece part 21a, 21a. Each anchor part 21b is electrically insulated from the frame piece part 21a, and the vibrator 23 And the same potential. In addition, an electrode terminal T1 made of a metal film is formed on the surface opposite to the base substrate 1 side of one anchor portion 21b of the two anchor portions 21b and 21b, and the electrode terminal T1 is connected to the vibrator 23. Electrically connected.

  The above-mentioned fixed electrode 24 has a comb shape in plan view, and the comb bone portion 24a is constituted by the central piece of the frame piece portion 21a of the frame portion 21, and the surface of the comb bone portion 24a that faces the movable element 23. A large number of fixed comb teeth 24b are arranged along the direction in which the pair of support springs 22 and 22 are arranged side by side. On the other hand, the movable electrode 25 is composed of a movable element 23, and on the side surface of the fixed electrode 24 on the side of the comb portion 24 a, a large number of movable comb teeth 25 b respectively facing the fixed comb teeth 24 b are arranged in the parallel direction. Are lined up. Here, each fixed comb tooth piece 24b and each movable comb tooth piece 25b are separated from each other.

  The base substrate 10 is formed by using a single silicon substrate 10a, and electrets 30 are formed at portions facing the comb portions 24a of the fixed electrodes 24 on the one surface side. On the other hand, in the frame portion 21, a recess 27 is formed at a portion that also serves as the comb bone portion 24 a of the fixed electrode 24, and a gap 51 is formed between the comb bone portion 24 a of the fixed electrode 24 and the electret 30. Has been. Here, the electret 30 is formed by charging a silicon oxide film formed on the one surface side of the base substrate 10 and holds a permanent charge (positive charge). Here, the silicon oxide film to be the electret 30 may be formed by, for example, a thermal oxidation method or a CVD method. The electret 30 charges the silicon oxide film by corona discharge or the like.

  The base substrate 10 has an electrode terminal T2 made of a metal film electrically connected to the above-described electret 30 on the other surface side.

In the power generation device of the present embodiment, the variable capacitor 26 having the fixed electrode 24 and the movable electrode 25 as the electrodes is formed as described above. Therefore, when the vibrator 23 vibrates, the fixed electrode 24 and the movable electrode 25 are , And the capacitance of the variable capacitor 26 changes. Here, the equivalent circuit of the power generation device of the present embodiment has a configuration in which a series circuit of a variable capacitor 26 and an electret 30 is connected as shown in FIG. If a load resistor R (see FIGS. 2B and 2C) is connected between T2 (that is, between both ends of the series circuit of the variable capacitor 26 and the electret 30), the electrostatic capacity of the variable capacitor 26 can be increased. When the capacitance changes, electric charge moves and current i (see FIG. 2C) flows, so that vibration energy of the mover 23 generated by vibration of the vibrator 23 can be converted into electric energy. 2B and 2C are explanatory views of the power generation principle of the power generation device of the present embodiment. FIG. 2B is a diagram illustrating the static capacitance of the variable capacitor 26 in a state where the vibrator 23 is not displaced. state capacitance _{C 0,} charge + _{Q 0} of the positive electrode side, the charge on the negative electrode side and -Q _0, has indicated the electret 30 as a voltage source _{V in,} FIG. (c) is that the vibrator 23 is displaced the electrostatic capacitance of the variable capacitor 26 C _1, charge + Q 1 on the positive electrode _side, the charge of the negative electrode side and -Q _1, the electret 30 and a voltage source V _in, there describes a current flowing as i in .

  By the way, each support spring part 22 and 22 in the electric power generation device of this embodiment is a torsion spring (torsion bar) which can be twisted, and is formed thinly compared with frame part 21 and vibrator 23, The vibrator 23 can be displaced around the pair of support spring portions 22, 22 with respect to the frame portion 21. That is, the pair of support springs 22 and 22 connect the frame part 21 and the vibrator 23 so that the vibrator 23 can swing with respect to the frame part 21. In other words, the vibrator 23 arranged inside the frame portion 21 is supported by the frame portion 21 so as to be swingable via the two support spring portions 22 and 22 extended in two opposite directions from the vibrator 23. Has been. Here, a concave portion (not shown) for securing a displacement space of the vibrator 23 is formed on the one surface of the base substrate 10, but without forming the concave portion in the base substrate 10, the vibrator It is also possible to secure a displacement space toward the base substrate 10 by reducing the thickness of 23.

  Here, assuming that the spring constant of the support spring portion 22 is k and the moment of inertia of the vibrator 23 is I, the resonance frequency (frequency) f of the vibrator 23 is expressed by the following formula 1.

ここにおいて、支持ばね部２２のばね定数ｋは、当該支持ばね部２２の材料（本実施形態では、Ｓｉ）のヤング率をＧとし、支持ばね部２２の寸法に関して、図３（ｂ）に示すように支持ばね部２２の幅をｗ_ｔ、厚さをｔ_ｔ、長さをｌ_ｔとすると、下記数２で表される。

Here, the spring constant k of the support spring part 22 is shown in FIG. 3B regarding the dimensions of the support spring part 22 with the Young's modulus of the material of the support spring part 22 (Si in this embodiment) as G. Thus, when the width of the support spring portion 22 is w _t , the thickness is t _t , and the length is l _t , the following expression 2 is obtained.

また、振動子２３の慣性モーメントＩは、振動子２３の質量をＭとし、振動子２３の寸法に関して、図３（ａ）に示すように一対の支持ばね部２２，２２の長手方向（両支持ばね部２２，２２を結ぶ方向）に直交する方向の長さをＬ、振動子２３の厚さをＨとすると、下記数３で表される。

Further, the moment of inertia I of the vibrator 23 is that the mass of the vibrator 23 is M, and the dimension of the vibrator 23 is the longitudinal direction of the pair of support springs 22 and 22 (both supports) as shown in FIG. When the length in the direction orthogonal to the direction connecting the spring portions 22 and 22 is L, and the thickness of the vibrator 23 is H, the following equation 3 is obtained.

また、振動子２３の質量Ｍは、振動子２３の材料の密度をρとし、振動子２３の寸法に関して、図３（ａ）に示すように一対の支持ばね部２２，２２の長手方向に沿った方向の寸法をＷとすると、下記数４で近似できる。

In addition, the mass M of the vibrator 23 is set such that the density of the material of the vibrator 23 is ρ, and the dimensions of the vibrator 23 are along the longitudinal direction of the pair of support spring portions 22 and 22 as shown in FIG. If the dimension in the direction is W, it can be approximated by the following equation (4).

ここで、振動子２３の平面サイズを変えて支持ばね部２２の長さｌ_ｔを種々変化させた場合の共振周波数ｆを上記数１〜４に基づいて求めた結果を図４に示す。図４から、振動子２３および支持ばね部２２，２２の平面サイズを小さくしても、共振周波数を低減でき、また、支持ばね部２２の長さを短くしても低周波領域の共振周波数ｆを実現することができることが分かる。

Here, FIG. 4 shows a result of obtaining the resonance frequency f based on the above _equations 1 to 4 when the planar size of the vibrator 23 is changed and the length l _t of the support spring portion 22 is variously changed. From FIG. 4, it is possible to reduce the resonance frequency even if the planar size of the vibrator 23 and the support springs 22 and 22 is reduced, and the resonance frequency f in the low frequency region can be reduced even if the length of the support spring 22 is reduced. It can be seen that can be realized.

  In the power generation device of the present embodiment described above, the support spring portions 22 and 22 are formed of torsion springs that can be twisted and deformed so that the vibrator 23 can swing with respect to the frame portion 21. Compared to the configuration in which the support spring portion 22 ′ and the mover 23 ′ vibrate in the direction along the one surface of the base substrate 10 ′ as in the conventional configuration shown, the support spring portions 22, 22 and the mover 23. The occupied area including the movable range can be reduced, and the planar size can be reduced.

  Further, in the power generation device of the present embodiment, the fixed electrode 24 is formed in a comb shape in plan view, and the movable electrode 25 has a plurality of movable comb teeth pieces 25b facing the plurality of fixed comb teeth pieces 24b of the fixed electrode 24. Therefore, the capacitance of the variable capacitor 26 can be increased as compared with the case where the fixed comb tooth piece 24b and the movable comb tooth piece 25b are not formed. Therefore, the variable capacitor when the vibrator 23 vibrates. The amount of change in the electrostatic capacity 26 can be increased, and the energy conversion efficiency can be improved.

  Further, in the power generation device of the present embodiment, the variable capacitors 26 are formed on both sides in the direction orthogonal to the direction connecting the support spring portions 22 and 22 in a plan view from the one surface side of the base substrate 10. However, in any case, the amount of change in the capacitance of the variable capacitor 26 when the vibrator 23 vibrates can be increased, and the energy conversion efficiency can be improved.

  However, an electrostatic attractive force in the direction indicated by the arrow in FIGS. 5A and 5B is generated between the movable electrode 25 and the fixed electrode 24, so that the support springs 22 and 22 are connected in the direction. When the variable capacitor 26 is formed on only one of the two sides in the orthogonal direction, a pull-in occurs in which the movable electrode 25 on the high potential side contacts the fixed electrode 24 on the low potential side by electrostatic attraction. It is possible.

  On the other hand, if the variable capacitor 26 is formed on both sides in the direction orthogonal to the direction connecting both the support springs 22, 22 as in the power generation device of this embodiment, both support springs 22, 22 are formed. The electrostatic attractive force generated between the movable electrode 25 and the fixed electrode 24 can be canceled on both sides in the direction orthogonal to the direction connecting the two, and the pull-in where the movable electrode 25 contacts the fixed electrode 24 by the electrostatic attractive force is suppressed. can do.

  Further, in the power generation device of the present embodiment, since the voltage applying means for applying a voltage to the variable capacitor 26 is constituted by the electret 30, compared to the case where a piezoelectric conversion element or a secondary battery is used as the voltage applying means. The planar size can be reduced.

(Embodiment 2)
The basic configuration of the power generation device of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 6, the base substrate 10 is formed using one glass substrate 10b, and the base substrate 10 is formed on the one surface. A first concave portion 11 that secures a displacement space of the vibrator 23 to the side is formed, and a rectangular plate shape formed by using one glass substrate 50b on the opposite side of the frame portion 21 from the base substrate 10 side. The difference is that the cover substrate 50 is fixed. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  The above-described cover substrate 50 is formed in the same plane size as the base substrate 10, and a second recess that secures a displacement space of the vibrator 23 toward the cover substrate 50 on the side facing the base substrate 10. (Not shown) is formed.

  Further, in the power generation device of the present embodiment, a frame-like (in this embodiment, a rectangular frame shape) outer frame portion 28 surrounding the frame portion 21 is fixed to the one surface side of the base substrate 10. 28 is fixed over the entire outer periphery of the cover substrate 50. Here, the outer frame part 28 is configured by a part of the frame part 21, the vibrator 23, and the silicon substrate 20a that is the basis of each support spring part 22, 22, and the outer frame part 28 and the frame part 21 are After the silicon substrate 20a is appropriately processed, it is separated after being bonded to the base substrate 10 by anodic bonding. Further, the outer frame portion 28 and the frame portion 21 are joined to the cover substrate 50 by anodic bonding. Note that the cover substrate 50 is not limited to a glass substrate, and may be a silicon substrate.

  In the power generation device of the present embodiment described above, an airtight package is configured by the base substrate 10, the outer frame portion 28, and the cover substrate 50. Therefore, if the inside of the airtight package is evacuated, air generated by the air of the vibrator 23 is used. Damping can be prevented, energy conversion efficiency can be improved, and reliability can be improved.

(Embodiment 3)
Hereinafter, the power generation device of the present embodiment will be described with reference to FIGS.

  The basic configuration of the power generation device of the present embodiment is substantially the same as that of the first embodiment, and the base substrate 10 is formed using a single glass substrate 10b, and includes a frame portion 21, support spring portions 22, and a mover 23. Is formed using an SOI substrate 200 having an n-type silicon layer (active layer) 200 cc on an insulating layer (buried oxide film) 200 b made of a silicon oxide film on a support substrate 200 a made of a silicon substrate. Etc. are different. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  In the power generation device of the present embodiment, each of the frame piece portions 21a and 21a and the anchor portions 21b and 21b of the frame portion 21 is electrically insulated by the insulating layer 200b. Therefore, the slit 21c described above is formed only in the silicon layer 200c, and the frame portion 21 is formed in a rectangular frame shape as a whole.

  Further, the base substrate 10 is formed such that the electret 30 has the surface of the electret 30 slightly retracted from the one surface (specifically, the formation region of the electret 30 on the one surface side of the base substrate 10). The electrode terminal T2 formed on the other surface side passes through the through-wiring 13 penetrating in the thickness direction of the glass substrate 10b. The electret 30 is electrically connected.

  Further, the power generation device of the present embodiment is configured on the one surface side of the base substrate 10 by a part of the silicon layer 200c in each of the frame piece portions 21a and 21a and the anchor portions 21b and 21b of the frame portion 21. Each part is joined by anodic bonding. Here, the base substrate 10 is formed with a notch portion 14 that exposes the electrode terminal T1 that is electrically connected to the anchor portion 21b.

  In the power generation device of the present embodiment described above, the frame portion 21, the vibrator 23, and the support spring portions 22, 22 are formed using the SOI substrate 200, so that each support spring portion 22 is compared to the first embodiment. , 22 can be improved in accuracy of the thickness dimension, and the accuracy of the resonance frequency of the vibrator 23 can be improved.

(Embodiment 4)
The basic configuration of the power generation device of the present embodiment shown in FIG. 10 (f) is substantially the same as that of the third embodiment, and the frame piece portions 21a and 21a and the anchors of the frame portion 21 are formed on the one surface side of the base substrate 10. Each of the portions 21b and 21b is different in that each portion constituted by a part of the silicon layer 200c is bonded via a bonding layer 41 made of a bonding resin (for example, epoxy resin). In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 3, and description is abbreviate | omitted.

  In the power generation device of the present embodiment, the internal electrode 15 made of a metal film is formed immediately below the electret 30 on the one surface side of the base substrate 10, and the internal electrode 15 is connected to the electrode terminal T <b> 2 via the through wiring 13. And are electrically connected.

  Hereinafter, the method for manufacturing the power generation device according to the present embodiment will be described with reference to FIG. 10, but a vibrator formation substrate having the vibrator 23, the frame portion 21, and both support spring portions 22, 22 is formed (a1) ˜. The order of the series of steps (e1) and the series of steps (a2) to (d2) for forming the base substrate 10 is not particularly limited. 10, (a1) to (e1) show cross sections corresponding to the AA ′ cross section of FIG. 7, and (a2) to (d2) show cross sections corresponding to the BB ′ cross section of FIG. ing.

  First, a series of steps (a1) to (e1) will be described.

  The structure shown in FIG. 10B1 is obtained by performing an electrode forming step of forming the electrode terminal T1 on one surface of the SOI substrate 200 shown in FIG. In the electrode formation process, for example, a metal film that is the basis of the electrode terminal T1 is formed on the entire surface of the one surface side of the SOI substrate 200 by sputtering, vapor deposition, CVD, or the like, and then photolithography technology and etching technology are used. The electrode terminal T1 made of a part of the metal film may be formed by patterning the metal film using it.

  After the above-described electrode formation step, a portion corresponding to the slit 21c in the silicon layer 200c of the SOI substrate 200, a portion between the frame portion 21 and the vibrator 23, and a portion between the movable electrode 25 and the fixed electrode 24 are The structure shown in FIG. 10C1 is obtained by performing a silicon layer patterning process in which etching is performed from the one surface side of the SOI substrate 200 using photolithography technology and etching technology.

  Thereafter, in the insulating layer 200b of the SOI substrate 200, an insulating layer that etches a portion between the frame portion 21 and the vibrator 23 and a portion between the movable electrode 25 and the fixed electrode 24 from the one surface side of the SOI substrate 200. The structure shown in FIG. 10D1 is obtained by performing the patterning process.

  Thereafter, a portion of the support substrate 200a of the SOI substrate 200 between the frame portion 21 and the vibrator 23, a portion between the movable electrode 25 and the fixed electrode 24, and a portion immediately below each of the support spring portions 22 and 22 are designated as SOI substrates. By performing a support substrate patterning step of etching from the other surface side of 200, a vibrator forming substrate having a structure shown in FIG. 10E1 is obtained.

  Next, a series of steps (a2) to (d2) will be described.

  A concave portion (hereinafter referred to as a displacement space forming concave portion) 11 is formed on one surface side of the glass substrate 10b shown in FIG. The structure shown in FIG. 10B2 is obtained by performing the first sandblasting process for forming the recesses 14a and 12a in the portions corresponding to the through holes 12, respectively.

  Then, the structure shown in FIG. 10C2 is obtained by performing a second sand blasting process for forming the notch 14 and the through hole 12 in the glass substrate 10b by the sand blasting method.

  Then, after performing the penetration wiring formation process which forms the penetration wiring 13 in the penetration hole 12 of the glass substrate 10b, the electrode formation process which forms the electrode terminal T2 and the internal electrode 15 is performed, FIG.10 (d2). A base substrate 10 having the structure shown is obtained.

  After forming the above-described vibrator formation substrate and the base substrate 10, the electret 30 is formed on the base substrate 10, and then the vibrator formation substrate and the base substrate 10 are connected via the bonding layer 41 made of epoxy resin or the like. By joining, the electric power generation device of the structure shown in FIG.10 (f) is obtained.

  In the power generation device of the present embodiment described above, the above-described vibrator formation substrate and the base substrate 10 are bonded via the bonding layer 41 made of epoxy resin or the like, so that compared with the case where both are bonded by anodic bonding. Thus, the characteristic deterioration of the electret 30 can be suppressed at the time of joining.

1 is a schematic perspective view showing a first embodiment. The same as above, (a) is an equivalent circuit diagram, (b), (c) is an operation explanatory diagram. It is principal part explanatory drawing same as the above. It is characteristic explanatory drawing same as the above. It is principal part explanatory drawing same as the above. FIG. 6 is a schematic exploded perspective view showing a second embodiment. 6 is a schematic exploded perspective view showing a third embodiment. FIG. It is a schematic perspective view same as the above. It is a schematic perspective view of the cover board | substrate in the same as the above. It is a main process schematic sectional drawing for demonstrating the manufacturing method of Embodiment 4. A prior art example is shown, (a) is a schematic perspective view partly broken, (b) is a schematic sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Base substrate 10a Silicon substrate 20a Silicon substrate 21 Frame part 22 Support spring part 23 Vibrator 24 Fixed electrode 24b Fixed comb tooth piece 25 Movable electrode 25 Movable comb tooth piece 26 Variable capacity capacitor 30 Electret (voltage application means)
51 Air gap T1, T2 Electrode terminal

Claims (3)

A base substrate, wherein a frame portion fixed to one surface of the base over the scan board, and the frame portion vibrator inside smell Te are arranged spaced apart from the base over scan substrate, the frame portion provided a pair of support spring portion is arranged in a manner sandwiching the vibration Doko inside and connecting the Doko vibration the said frame portion, said fixed electrode oscillation Doko provided on the frame portion and a variable capacitance capacitor configured with the movable electrode which is provided with a voltage applying means for applying a voltage to the variable - capacitance capacitor, the supporting lifting spring portion, the vibration Doko with respect to the frame part It comprises a torsion spring capable of torsional deformation so as to be swingable , the fixed electrode is formed in a comb shape in plan view, and the movable electrode is a plurality of fixed comb teeth facing the fixed electrode. A movable comb-teeth piece; The electret is formed in a portion facing the comb bone portion of the fixed electrode on the one surface side of the base substrate, and the frame portion is a portion also serving as the comb bone portion of the fixed electrode. A recess is formed, and a gap is formed between the comb portion of the fixed electrode and the electret, and is electrically connected to the electrode terminal and the electret electrically connected to the movable electrode A power generating device , wherein a series circuit of the variable capacitor and the electret is connected between the electrode terminals . 2. The variable capacitor according to claim 1, wherein the variable capacitor is formed on at least one of both sides in a direction orthogonal to a direction connecting the two support springs in a plan view from the one surface side of the base substrate. Power generation device. The variable capacitor, 請 Motomeko 2 wherein you characterized by comprising formed on both sides in the direction perpendicular to the direction connecting the both supporting spring portion in a plan view from the one surface side of the base substrate Power generation device .

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