JP6170218B2 - Power generation element - Google Patents

Description

  The present invention relates to a power generation element, and more particularly to a technique for generating power by converting vibration energy into electric energy.

  In order to make effective use of limited resources, techniques for converting various forms of energy into electrical energy and taking them out have been proposed. One technique is to extract vibration energy by converting it into electrical energy. For example, in Patent Document 1 below, a piezoelectric element for power generation is formed by laminating layered piezoelectric elements, and the piezoelectric element for power generation is externally applied. There is disclosed a piezoelectric power generation element that generates power by vibrating it. Patent Document 2 discloses a power generation element having a micro electro mechanical system (MEMS) structure using a silicon substrate.

  On the other hand, Patent Document 3 uses a hammerhead type structure that supports a weight body by a cantilever beam with one end fixed, and the weight body constituting the head portion is vibrated and disposed on the handle portion. A type of power generation element that generates power using a power generation piezoelectric element is disclosed. Further, Patent Document 4 discloses a piezoelectric element using a structure that supports a weight body with a plate-shaped bridge portion bent in an L shape, together with a power generation element that uses this hammerhead structure. .

  The basic principle of these power generation elements is to cause periodic bending of the piezoelectric element due to vibration of the weight body, and to extract the electric charge generated based on the stress applied to the piezoelectric element to the outside. If such a power generation element is mounted on, for example, an automobile, a train, a ship, etc., vibration energy applied during transportation can be taken out as electric energy. It is also possible to generate electricity by attaching it to a vibration source such as a refrigerator or an air conditioner.

JP-A-10-243667 JP 2011-152010 A US Patent Publication No. 2013/0154439 WO2015 / 033621

  When the power generation element is mounted on a transport device such as an automobile, a train, or a ship, a force is applied from a random direction during operation. Therefore, in a power generation element mounted on such a transport device, it is assumed that the weight body vibrates in various directions, and it is possible to convert the vibration energy in all directions into electric energy to improve the power generation efficiency. It is preferable in terms of improvement.

  Further, in the power generating element using the plate-like bridge portion disclosed in Patent Documents 3 and 4 described above, there is an advantage that the structure can be simplified and the cost can be reduced. In order to generate sufficient deflection and improve power generation efficiency, it is necessary to make the plate-like bridge portion as long and thin as possible. For this reason, when an excessive vibration is added, a plate-shaped bridge part may be damaged.

  Therefore, the present invention can obtain high power generation efficiency by converting vibration energy including various directional components into electric energy without waste while having a simple structure, and excessive vibration is added. An object of the present invention is to provide a power generation element that is not easily damaged.

(1) A first aspect of the present invention is a power generation element that generates power by converting vibration energy into electrical energy.
A plate-like bridge portion extending along the first longitudinal axis and having flexibility;
A pedestal for supporting and fixing the root end portion of the plate-like bridge portion;
A weight body connected directly or indirectly to the tip of the plate-like bridge portion;
A piezoelectric element fixed at a predetermined position where expansion and contraction of the surface of the plate-like bridge portion occurs;
A power generation circuit that rectifies a current generated based on the electric charge generated in the piezoelectric element and extracts power;
Provided,
The weight body has a left wing weight portion located on the left side with respect to the longitudinal axis of the plate-like bridge portion, and a right wing weight portion located on the right side with respect to the longitudinal direction axis of the plate-like bridge portion. It is what I did.

(2) According to a second aspect of the present invention, in the power generation element according to the first aspect described above,
The weight support part is connected to the tip of the plate-like bridge part, and the weight body is connected to the lower surface of the weight support part so that the center of gravity of the weight body is located below the plate-like bridge part. Is.

(3) A third aspect of the present invention is the power generation element according to the second aspect described above,
The weight support portion has a central plate-like portion extending along the second longitudinal axis perpendicular to the first longitudinal axis, and the tip of the plate-like bridge portion is located near the center of the central plate-like portion. Connected, and a T-shaped structure is formed by the plate-like bridge portion and the central plate-like portion,
The left wing weight portion is connected to the lower surface on the left side of the central plate-shaped portion, and the right wing weight portion is connected to the lower surface on the right side of the central plate-shaped portion.

(4) According to a fourth aspect of the present invention, in the power generation element according to the second aspect described above,
A weight support portion extends along a second longitudinal axis orthogonal to the first longitudinal axis, and a central plate-like portion whose central vicinity is connected to the tip of the plate-like bridge portion; A left wing plate-like portion extending from the left side of the plate-like bridge portion to the left side of the plate-like bridge portion, and a right wing plate-like portion extending from the right side of the central plate-like portion to the right side of the plate-like bridge portion,
The left wing weight portion is connected to the lower surface of the left wing plate-like portion, and the right wing weight portion is connected to the lower surface of the right wing plate-like portion.

(5) According to a fifth aspect of the present invention, in the power generation element according to the third or fourth aspect described above,
The weight body has a central weight portion that connects the left wing weight portion and the right wing weight portion, and the central weight portion is connected to the lower surface of the central plate-shaped portion.

(6) A sixth aspect of the present invention is the power generation element according to the first to fifth aspects described above,
A pedestal connection portion extending along a third longitudinal axis perpendicular to the first longitudinal axis is connected to the root end portion of the plate-like bridge portion, and this pedestal connection portion is fixed to the pedestal. .

(7) According to a seventh aspect of the present invention, in the power generation element according to the first to sixth aspects described above,
The pedestal is composed of an annular structure that surrounds the plate-shaped bridge portion and the weight body, and when an acceleration exceeding a predetermined size acts on the power generation element, a part of the weight body is the annular structure. It touches a part of the body so that further displacement is limited.

(8) The eighth aspect of the present invention is the power generation element according to the first to seventh aspects described above,
A piezoelectric element is disposed on the left side in the vicinity of the tip of the plate-like bridge portion, the left-side piezoelectric element on the tip, the right-side tip of the piezoelectric element in the vicinity of the tip of the plate-like bridge portion, and the plate-like bridge portion A root end left side piezoelectric element disposed on the left side near the root end part of the plate, and a root end right side piezoelectric element disposed on the right side near the root end part of the plate-like bridge portion. .

(9) According to a ninth aspect of the present invention, in the power generation element according to the first to eighth aspects described above,
A piezoelectric element includes a lower layer electrode formed in a layer on the surface of the plate-like bridge portion, a piezoelectric material layer formed in a layer on the surface of the lower electrode, and a plurality of locally formed surfaces on the surface of the piezoelectric material layer. The piezoelectric material layer is made of a material having a property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction.

(10) According to a tenth aspect of the present invention, in the power generation apparatus configured by housing the power generation element according to the first to ninth aspects described above in the apparatus housing,
When the pedestal of the power generation element is fixed to the device housing and an external force that vibrates the device housing is applied, the weight of the power generation device vibrates in the device housing due to the bending of the plate-like bridge, and the vibration In response to this, the electric power extracted from the power generation circuit is output.

(11) An eleventh aspect of the present invention is a power generation apparatus configured by housing the power generation element according to the first to ninth aspects described above in an apparatus housing.
When the weight of the power generation element is fixed to the device housing and an external force that vibrates the device housing is applied, the base of the power generation device vibrates in the device housing due to the bending of the plate-like bridge, and the vibration In response to this, the electric power extracted from the power generation circuit is output.

(12) A twelfth aspect of the present invention is a power generating element that generates power by converting vibration energy in each coordinate axis direction into electric energy in an XYZ three-dimensional coordinate system.
When the XY plane is a horizontal plane, the Z-axis positive direction is the upward direction, and the Z-axis negative direction is the downward direction, the main power generation first layer, the main power generation second layer, and the main power generation third layer are stacked in order from the top. A main power generation structure;
A base for supporting and fixing a predetermined portion of the main power generation structure;
A power generation circuit that rectifies a current generated based on the charge generated by the main power generation structure and extracts power;
Provided,
The main power generation second layer is a flat plate-like layer arranged along a plane parallel to the XY plane, and supports a flexible plate-like bridge portion arranged on the Y axis and the main power generation third layer. A weight body support for
The weight body support portion has a central plate-like portion disposed on the X ′ axis, which is an axis that intersects the Y axis and is parallel to the X axis,
The plate-like bridge portion extends from the root end portion to the tip portion along the Y axis, the center plate portion extends along the X ′ axis so as to intersect the Y axis, and intersects the Y axis of the center plate portion. The tip of the plate-like bridge portion is connected in the vicinity of the portion, and the XY plane projection image of the plate-like bridge portion and the central plate-like portion has a T shape,
The main power generation first layer has a piezoelectric element formed so as to cover at least a part of the upper surface of the plate-like bridge portion of the main power generation second layer,
The main power generation third layer is connected to the bottom surface of the weight body support portion of the main power generation second layer, and has a mass having a mass sufficient to cause the plate-like bridge portion to bend based on the applied acceleration. Functions as a weight,
For both sides of the plate-like bridge part, when the side where the X coordinate value is negative is defined as the left side and the side where the X coordinate value is positive is defined as the right side, the main power generation third layer is It has a left wing weight part located on the left side and a right wing weight part located on the right side,
The pedestal supports and fixes the root end of the plate bridge,
The power generation circuit is configured to rectify a current generated based on the electric charge generated in the piezoelectric element and extract electric power.

(13) A thirteenth aspect of the present invention is the power generating element according to the twelfth aspect described above,
The weight support part of the second layer of the main power generation extends from the left side of the central plate-like part to the left side of the plate-like bridge part along the direction parallel to the Y axis, and the right side of the central plate-like part A right wing plate-like portion extending to the right side of the plate-like bridge portion along a direction parallel to the Y-axis,
The left wing weight portion is connected to the lower surface of the left wing plate-like portion, and the right wing weight portion is connected to the lower surface of the right wing plate-like portion.

(14) According to a fourteenth aspect of the present invention, in the power generation element according to the twelfth or thirteenth aspect described above,
The main power generation third layer has a central weight part that connects the left wing weight part and the right wing weight part, and the central weight part is connected to the lower surface of the central plate-like part, An XY plane projection image of a weight body having a right wing weight portion and a central weight portion is formed in a “U” shape.

(15) According to a fifteenth aspect of the present invention, in the power generation element according to the twelfth to fourteenth aspects described above,
The center of gravity of the structure constituting the main power generation third layer is located below the plate-like bridge portion.

(16) In a sixteenth aspect of the present invention, in the power generation element according to the twelfth to fifteenth aspects described above,
The main power generation structure is plane-symmetric with respect to the YZ plane, and the center of gravity of the structure constituting the main power generation third layer is located on the YZ plane below the plate-like bridge portion.

(17) According to a seventeenth aspect of the present invention, in the power generation element according to the twelfth to sixteenth aspects described above,
The XY plane projection image of the main power generation first layer and the XY plane projection image of the main power generation second layer have the same shape, and the entire area of the lower surface of the main power generation first layer is the entire area of the upper surface of the main power generation second layer. It is made to be joined.

(18) An eighteenth aspect of the present invention is the power generation element according to the twelfth to seventeenth aspects described above,
The end of the main power generation third layer in the X-axis positive direction protrudes in the X-axis positive direction from the end of the weight support portion in the X-axis positive direction, and the end of the main power generation third layer in the X-axis negative direction The portion protrudes in the X-axis negative direction from the end portion in the negative X-axis direction of the weight support portion, and the Y-axis positive direction end portion of the main power generation third layer is the positive Y-axis direction of the weight support portion Projecting in the Y-axis positive direction from the end of the main power generation, and the Y-axis negative direction end of the main power generation third layer projecting in the Y-axis negative direction from the end of the weight support portion in the Y-axis negative direction It is what you have.

(19) According to a nineteenth aspect of the present invention, in the power generation element according to the twelfth to eighteenth aspects described above,
The main power generation first layer is formed locally on the surface of the plate-like bridge portion, the lower layer electrode formed in layers, the piezoelectric material layer formed in layers on the surface of the lower layer electrode, and the surface of the piezoelectric material layer And an upper electrode group composed of a plurality of upper layer electrodes,
The piezoelectric material layer has the property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction,
The power generation circuit rectifies the current generated based on the electric charges generated in the upper layer electrode and the lower layer electrode to extract electric power.

(20) According to a twentieth aspect of the present invention, in the power generation element according to the nineteenth aspect described above,
The upper layer electrode group includes a tip left upper layer electrode, a tip right upper layer electrode, a root left upper layer electrode, and a root right upper layer electrode.
The projected image of the upper left electrode of the tip portion on the upper surface of the main power generation second layer extends in a direction parallel to the Y axis, and is located on the side where the X coordinate value near the tip portion of the plate-like bridge portion is negative,
The projected image on the upper surface of the main power generation second layer of the upper right electrode of the tip portion extends in a direction parallel to the Y axis, and is located on the side where the X coordinate value near the tip portion of the plate-like bridge portion becomes positive,
The projection image of the upper left electrode of the root end portion on the upper surface of the main power generation second layer extends in a direction parallel to the Y axis, and is located on the side where the X coordinate value near the root end portion of the plate-like bridge portion is negative.
The projected image of the upper right electrode at the root end portion on the upper surface of the main power generation second layer extends in a direction parallel to the Y axis, and is positioned on the side where the X coordinate value near the root end portion of the plate-like bridge portion is positive. It is a thing.

(21) According to a twenty-first aspect of the present invention, in the power generation element according to the nineteenth or twentieth aspect described above,
The power generation circuit includes a capacitive element and a positive charge rectifying element having a forward direction from each upper layer electrode toward the positive electrode side of the capacitive element to guide the positive charge generated in each upper electrode to the positive electrode side of the capacitive element; A negative charge rectifying element whose forward direction is from the negative electrode side of the capacitive element to each upper layer electrode in order to guide the negative charge generated in each upper layer electrode to the negative electrode side of the capacitive element, and converts from vibration energy The electric energy is smoothed and supplied by a capacitive element.

(22) According to a twenty-second aspect of the present invention, in the power generation element according to the nineteenth to twenty-first aspects described above,
The piezoelectric material layer of the main power generation first layer is formed of a piezoelectric thin film, the upper electrode and the lower layer electrode of the main power generation first layer are formed of a metal layer, the main power generation second layer is formed of a silicon substrate, and the main power generation third The layer is constituted by a metal substrate, a ceramic substrate, or a glass substrate.

(23) According to a twenty-third aspect of the present invention, in the power generating element according to the twelfth to twenty-second aspects described above,
The pedestal forms an annular structure surrounding the main power generation structure along the XY plane, and when the horizontal component of acceleration exceeding a predetermined magnitude acts on the power generation element, the main power generation third layer is an annular structure. It touches the inner surface of the body and further displacement is limited.

(24) According to a twenty-fourth aspect of the present invention, in the power generating element according to the twenty-third aspect described above,
The pedestal comprises a rectangular ring-shaped structure having four sets of wall portions, the first wall portion, the second wall portion, the third wall portion, and the fourth wall portion,
The first wall portion is disposed adjacent to the main power generation structure on the negative X-axis direction side, and constitutes a wall surface along a plane parallel to the YZ plane,
The second wall portion is disposed adjacent to the main power generation structure on the X axis positive direction side, and constitutes a wall surface along a plane parallel to the YZ plane,
The third wall portion is disposed adjacent to the main power generation structure on the Y axis positive direction side, and constitutes a wall surface along a plane parallel to the XZ plane,
The fourth wall portion is arranged adjacent to the main power generation structure on the Y-axis negative direction side, and constitutes a wall surface along a plane parallel to the XZ plane,
The root end portion of the plate-like bridge portion is supported and fixed to the fourth wall portion.

(25) A twenty-fifth aspect of the present invention is the power generating element according to the twenty-third or twenty-fourth aspect described above,
The pedestal is constituted by a laminated structure in which the pedestal first layer, the pedestal second layer, and the pedestal third layer are laminated in order from the top, and the pedestal first layer is the main power generation first layer in the vicinity of the root end portion of the plate-like bridge portion. The pedestal second layer is connected to the main power generation second layer at the root end portion of the plate-like bridge portion.

(26) According to a twenty-sixth aspect of the present invention, in the power generation element according to the twenty-third or twenty-fourth aspect described above,
The main power generation second layer further has a base connection portion connected to the root end portion of the plate-like bridge portion,
The pedestal connecting portion is arranged on a predetermined arrangement axis that intersects the Y axis and is parallel to the X axis, and extends along the arrangement axis.
A fitting groove for fitting the pedestal connection portion is formed on the upper surface of a predetermined portion of the pedestal, and the pedestal connection portion is fixed in a state of being fitted in the fitting groove. .

(27) According to a twenty-seventh aspect of the present invention, in the power generation apparatus configured by housing the power generation element according to the twelfth to twenty-sixth aspects described above in the apparatus housing,
When the pedestal of the power generation element is fixed to the device housing, and an external force that vibrates the device housing acts, the main power generation third layer of the power generation device vibrates in the device housing due to the bending of the plate-like bridge portion, Electric power extracted from the power generation circuit is output in response to the vibration.

(28) According to a twenty-eighth aspect of the present invention, in the power generator according to the twenty-seventh aspect described above,
An apparatus housing is arranged so as to support and fix the power generation element from below, an upper lid substrate that covers the top of the power generation element, and a side wall that surrounds the power generation element and connects the base substrate and the upper lid substrate A board, and
The bottom surface of the pedestal of the power generation element is located below the bottom surface of the main power generation third layer of the power generation element, and the bottom surface of the pedestal is fixed to the top surface of the base substrate, and the top surface of the base substrate and the bottom surface of the main power generation third layer A lower gap is formed between
The upper lid substrate is located above the upper surface of the main power generation first layer of the power generation element, and an upper gap is formed between the lower surface of the upper lid substrate and the upper surface of the main power generation first layer,
When a vertical component of acceleration exceeding a predetermined magnitude is applied to the power generation element, a part of the main power generation structure comes into contact with the upper surface of the base substrate or the lower surface of the upper cover substrate, and further displacement is limited. It was made to do.

(29) According to a twenty-ninth aspect of the present invention, in the power generation apparatus configured by housing the power generation element according to the twelfth to twenty-sixth aspects described above in the apparatus housing,
The main power generation third layer of the power generation element is fixed to the device housing, and when an external force that vibrates the device housing is applied, the pedestal of the power generation device is vibrated in the device housing due to the bending of the plate-like bridge portion, Electric power extracted from the power generation circuit is output in response to the vibration.

(30) According to a thirtieth aspect of the present invention, in the power generation device according to the twenty-ninth aspect described above,
An apparatus housing is arranged so as to support and fix the power generation element from below, an upper lid substrate that covers the top of the power generation element, and a side wall that surrounds the power generation element and connects the base substrate and the upper lid substrate A board, and
The bottom surface of the base of the power generation element is located above the bottom surface of the main power generation third layer of the power generation element, and the bottom surface of the main power generation third layer is fixed to the top surface of the base substrate, and the top surface of the base substrate and the bottom surface of the base A lower gap is formed between
The upper lid substrate is located above the upper surface of the main power generation first layer of the power generation element, and an upper gap is formed between the lower surface of the upper lid substrate and the upper surface of the main power generation first layer,
When a vertical component of acceleration exceeding a predetermined size acts on the power generation element, a part of the pedestal comes into contact with the upper surface of the base substrate or the lower surface of the upper lid substrate, and further displacement is limited. It is a thing.

  (31) In a thirty-first aspect of the present invention, a power generating element structure is constituted by elements excluding the power generating circuit from the power generating elements according to the first to ninth and twelfth to twenty-sixth aspects described above. It is a thing.

  In the power generating element according to the present invention, a cantilever structure in which the root end portion of the flexible plate-like bridge portion is fixed to the pedestal and a weight body is connected to the tip portion is adopted, and the plate-like bridge portion is fixed. Electric power is generated by the piezoelectric element. In addition, the weight body has a left wing weight portion located on the left side of the plate-like bridge portion and a right wing weight portion located on the right side, so that the weight body has various directions with respect to the plate-like bridge portion. The external force to bend can be transmitted efficiently. In addition, by providing a member that limits the displacement of the left and right weight bodies, it becomes possible to limit the displacement of the plate bridge even when excessive vibration is applied, and damage the plate bridge Can be prevented.

  As described above, according to the present invention, it is possible to obtain high power generation efficiency by converting vibration energy including various directional components into electric energy without waste even though the structure is simple. A power generation element that is not easily damaged even when the vibration is applied can be realized.

It is a perspective view (separately showing three layer parts which constitute main power generation structure MGS) and a block diagram showing composition of power generation element PGE concerning a basic embodiment of the present invention. It is a top view of the main power generation first layer 100 of the main power generation structure MGS shown in FIG. FIG. 2 is a top view of a main power generation second layer 200 of the main power generation structure MGS shown in FIG. 1. FIG. 3 is a top view of a main power generation third layer 300 of the main power generation structure MGS shown in FIG. 1. It is a side view of the main power generation structure MGS shown in FIG. It is a top view which shows the state which fixed the main electric power generation structure MGS shown in FIG. 1 to the base 400 (The hatching is for showing the formation state of each upper layer electrode, and the fixed state by a base, and does not show a cross section. (The symbols in parentheses indicate the components arranged below.) FIG. 3 is a side sectional view showing a state where the main power generation structure MGS shown in FIG. 1 is fixed to a pedestal 400 (showing a section cut along a YZ plane). It is a top view which shows a deformation | transformation aspect when force + Fx of the X-axis positive direction acts on the main electric power generation structure MGS shown in FIG. FIG. 7 is a side sectional view showing a deformation mode when a force + Fy in the Y-axis positive direction is applied to the main power generation structure MGS shown in FIG. 1 (showing a section cut along a YZ plane). FIG. 7 is a side sectional view showing a deformation mode when a force + Fz in the positive Z-axis direction is applied to the main power generation structure MGS shown in FIG. 1 (showing a cross section cut along a YZ plane). FIG. 3 shows the stretching stress in the Y-axis direction applied to the positions of the upper layer electrodes E1 to E4 of the bridge portion piezoelectric layer 110 when a force in the positive direction of each coordinate axis acts on the weight body of the main power generation structure MGS shown in FIG. It is a table. 3 is a table showing polarities of charges generated in upper layer electrodes E1 to E4 when a force in the positive direction of each coordinate axis is applied to the weight body of the main power generation structure MGS shown in FIG. 1. FIG. 2 is a stress distribution diagram showing a Y-axis direction stress generated in a piezoelectric material layer 105 when an X-axis positive direction force + Fx acts on the weight body of the main power generation structure MGS shown in FIG. 1. FIG. 2 is a stress distribution diagram showing Y-axis direction stress generated in a piezoelectric material layer 105 when a force + Fy in the Y-axis positive direction is applied to the weight body of the main power generation structure MGS shown in FIG. 1. FIG. 2 is a stress distribution diagram showing a Y-axis direction stress generated in a piezoelectric material layer 105 when a positive Z-axis direction force + Fz is applied to the weight body of the main power generation structure MGS shown in FIG. 1. It is a circuit diagram which shows the specific structure of the electric power generation circuit 500 of the electric power generation element PGE shown in FIG. It is a top view which shows the electric power generation element PGE using the rectangular-shaped annular structure as the base 400 (a power generation circuit is abbreviate | omitting illustration). FIG. 18 is a front sectional view showing a section obtained by cutting the power generating element PGE shown in FIG. 17 along a cutting line 18-18. It is a sectional side view which shows the cross section which cut | disconnected the electric power generation element PGE shown in FIG. 17 along the cutting line 19-19. It is a sectional side view which shows the cross section which cut | disconnected the electric power generation element PGE shown in FIG. 17 along the cutting line 20-20. FIG. 18 is a side sectional view of a laminated material block 1000 used as a material constituting the main power generation structure MGS and the pedestal 400 of the power generation element PGE shown in FIG. 17. FIG. 18 is a side sectional view of a power generation device configured by housing the power generation element PGE shown in FIG. It is a sectional side view of the electric power generating apparatus which concerns on the modification which reversed the role of the weight body and base in the electric power generating apparatus shown in FIG. It is a top view which shows the 1st modification A of the main electric power generation structure MGS shown in FIG. 1 (The code | symbol in parenthesis has shown the component of the main electric power generation 2nd layer 200a arrange | positioned below.). . It is a top view which shows the 2nd modification B of the main electric power generation structure MGS shown in FIG. 1 (The code | symbol in parentheses has shown the component of the main electric power generation 2nd layer 200b arrange | positioned below.). . It is a top view which shows the connection angle of the both ends of the plate-shaped bridge part 210 in the main electric power generation 2nd layer 200 of the main electric power generation structure MGS shown in FIG. It is a top view which shows the main electric power generation 2nd layer 200c which concerns on the 3rd modification C of the main electric power generation structure MGS shown in FIG. FIG. 10 is a top view (FIG. (A)) and a front sectional view (FIG. (B)) showing a main power generation component 700d used in a fourth modification D of the main power generation structure MGS shown in FIG. In FIG. 1 (a), the reference numerals in parentheses indicate the constituent elements of each layer. It is a top view which shows the weight body 300d used for the 4th modification D of the main electric power generation structure MGS shown in FIG. It is a top view which shows the base 400d for fixing the 4th modification D of the main electric power generation structure MGS shown in FIG. It is a top view which shows the state which attached the main electric power generation component 700d shown in FIG. 28 and the weight body 300d shown in FIG. 29 to the base 400d shown in FIG.

  Hereinafter, the present invention will be described based on the illustrated embodiments.

<<< §1. Structure of power generation element according to basic embodiment >>
FIG. 1 is a perspective view and a block diagram showing a configuration of a power generating element PGE (abbreviation of Power Generating Element) according to a basic embodiment of the present invention. As shown in the perspective view portion, the power generating element PGE has a three-layer structure in which a first layer 100, a second layer 200, and a third layer 300 are stacked. In the perspective view of FIG. 1, for convenience of explanation, these three layers are shown in a vertically separated state, but in practice, the upper surface of the second layer 200 is fixed to the lower surface of the first layer 100, and the second layer 200. The upper surface of the third layer 300 is fixed to the lower surface of each of the three layers, and the three layers become a structure bonded to each other.

  This three-layer structure fulfills a fundamental power generation function in the power generation element PGE according to the present invention. Therefore, in the present application, this three-layer structure is referred to as a main power generation structure MGS (abbreviation of Main Generating Structure), the first layer 100 is “main power generation first layer”, and the second layer 200 is “main power generation first”. The second layer and the third layer 300 will be referred to as the “main power generation third layer”. The power generation element PGE according to the present invention further adds a pedestal 400 (indicated by simple symbol symbols in the figure) and a power generation circuit 500 (indicated by blocks in the figure) to the main power generation structure MGS having three layers. It is constituted by.

  The pedestal 400 plays a role of supporting and fixing a part of the main power generation structure MGS (the right end surface in the figure), and a specific structure thereof will be described in detail in §3. As described in §3, in the case of the basic embodiment of the present invention, the pedestal 400 also has a three-layer structure like the main power generation structure MGS. These are referred to as “first layer”, “pedestal second layer”, and “pedestal third layer”.

  Here, as shown in the perspective view of FIG. 1, the origin O is defined at the center position of the right end surface of the main power generation second layer 200, the X axis in the back direction, the Y axis in the left direction, and the Z axis in the upward direction, respectively. By doing so, an XYZ three-dimensional orthogonal coordinate system is defined. In the following description of the present application, as shown in the drawing, the upper and lower relationships between the components are described on the assumption that the XY plane is a horizontal plane, the Z-axis positive direction is upward, and the Z-axis negative direction is downward. To. Therefore, the main power generation structure MGS is a structure in which the main power generation first layer 100, the main power generation second layer 200, and the main power generation third layer 300 are stacked in order from the top.

  The power generating element PGE according to the present invention has a function of generating power by converting vibration energy in the direction of each coordinate axis in the XYZ three-dimensional coordinate system into electric energy. The illustrated coordinate system is an example used for convenience of explanation, and the position of the coordinate system is not necessarily the illustrated position. For example, the origin O may be defined not at the right end face position of the main power generation second layer 200 but at the center of gravity position of the main power generation second layer 200 or the like. However, since the right end surface of the main power generation second layer 200 is a portion fixed by the pedestal 400, here, for convenience of description, the origin O is defined at the center position of the right end surface, and the following description will be given.

  The main power generation first layer 100 is a flat plate-like structure whose planar shape is a letter “E”, and its main part is constituted by a piezoelectric material layer 105. More specifically, the main power generation first layer 100 includes a piezoelectric material layer 105, three layers of upper layer electrodes E1 to E4 formed in a predetermined region on the upper surface and a lower layer electrode E0 formed in the entire region on the lower surface. It is constituted by a structure. Here, the piezoelectric material layer 105 has a property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction. Therefore, when stress is applied to each part of the piezoelectric material layer 105 and bending occurs, polarization occurs in the thickness direction, and charges are generated in the upper layer electrodes E1 to E4 and the lower layer electrode E0.

  While the lower layer electrode E0 is a single common electrode formed on the entire lower surface of the piezoelectric material layer 105, each upper layer electrode E1 to E4 is a station formed in each predetermined region of the piezoelectric material layer 105. Depending on the direction of the applied external force, the direction of the stress applied to each part of the piezoelectric material layer 105 (compression direction stress or extension direction stress) differs, and the polarity of the generated charge may differ. Because there is.

  The power generation circuit 500 has a function of taking out electric power by rectifying a current generated based on the electric charge thus generated. The electric power generated by the power generation element PGE is supplied from the power generation circuit 500 to the outside. In FIG. 1, only the wiring for the upper layer electrode E4 and the lower layer electrode E0 is shown as the wiring for the power generation circuit 500 for the sake of convenience of illustration, but actually, the wiring between the upper layer electrodes E2 to E4 and the power generation circuit 500 is shown. The same wiring is also made.

  FIG. 2 is a top view of the main power generation first layer 100 of the main power generation structure MGS shown in FIG. 1, showing a two-dimensional plan view in which the X axis is the right direction of the drawing and the Y axis is the upward direction of the drawing. Has been. Note that the X axis, the Y axis, and the origin O shown in FIG. 2 are actually located below the main power generation first layer 100 (inside the main power generation second layer 200). As described above, in the main power generation first layer 100, the four upper layer electrodes E1 to E4 are formed on the upper surface of the “E” -shaped piezoelectric material layer 105, and the lower layer electrode E0 (FIG. 2) is formed on the lower surface. (Not shown).

  The piezoelectric material layer 105 is actually a single plate-like integrated structure having an “E” shape, but here, for convenience of explanation, four portions 110, 120, 130, and 140 as illustrated are shown. I will divide it into two. Each part is constituted by a flat piezoelectric material layer arranged along a plane parallel to the XY plane.

  The portion 110 is a portion having a bridge structure extending along the Y axis, and is referred to as a bridge portion piezoelectric layer 110 here. As shown in the figure, the bridge portion piezoelectric layer 110 is a portion arranged in a section from the origin O to the tip point T (a point defined on the Y axis) along the Y axis. The four upper layer electrodes E <b> 1 to E <b> 4 are all disposed on the upper surface of the bridge portion piezoelectric layer 110. Actually, the upper layer electrodes E1 to E4 and the lower layer electrode E0 are wired to the power generation circuit 500, but the wiring is not shown here.

  The portion 120 is a portion extending along the X′-axis (an axis that intersects the Y-axis and is parallel to the X-axis), and the central portion thereof is connected to the bridge portion piezoelectric layer 110 at the position of the tip point T. Here, this portion 120 is referred to as a central piezoelectric layer. The bridge portion piezoelectric layer 110 and the central piezoelectric layer 120 constitute a structure having a T-shaped planar shape.

  The portion 130 extends from the left side of the central piezoelectric layer 120 to the lower side of the figure, and is a wing-like portion disposed on the left side of the bridge portion piezoelectric layer 110. Here, the portion 130 is referred to as a left wing piezoelectric layer 130. To do. On the other hand, the portion 140 is a wing-like portion extending from the right side of the central piezoelectric layer 120 to the lower side of the drawing and disposed on the right side of the bridge portion piezoelectric layer 110. Here, the portion 140 is referred to as a right wing piezoelectric layer 140. I will decide.

  In this application, for convenience of explanation, as shown in FIG. 2, the left and right are defined with the top view in which the Y axis is drawn in the vertical direction in mind, so the side where the X coordinate value is negative with respect to the YZ plane is on the left side. The side where the X coordinate value is positive with respect to the Y axis is called the right side. According to such a definition, the left wing piezoelectric layer 130 is disposed on the left side of the bridge portion piezoelectric layer 110, and the right wing piezoelectric layer 140 is disposed on the right side of the bridge portion piezoelectric layer 110. Of course, such left and right definitions are definitions for convenience for explaining the relative positional relationship with respect to the YZ plane, and do not have an absolute meaning.

  In FIG. 2, the lower end (near the origin O) of the bridge portion piezoelectric layer 110 extends downward as compared with the lower end of the left wing piezoelectric layer 130 and the lower end of the right wing piezoelectric layer 140. This is because the vicinity of the origin O of the second main power generation layer is connected to the pedestal 400 as shown in the perspective view. As will be described later, stress concentration is observed in the vicinity of the connection end with the pedestal 400. Therefore, if the upper layer electrodes E3 and E4 are arranged in the stress concentration portion, more efficient power generation becomes possible.

  3 is a top view of the main power generation second layer 200 of the main power generation structure MGS shown in FIG. 1, and a two-dimensional plan view in which the X axis is the right direction of the figure and the Y axis is the upward direction of the figure. It is shown. The X-axis, Y-axis, and origin O shown in FIG. 3 are actually arranged at positions buried in the main power generation second layer 200 (intermediate positions in the thickness direction).

  The main power generation second layer 200 is also a plate-like structure having an “E” shape. In the case of the basic embodiment shown here, an XY plane projection image of the main power generation first layer 100 shown in FIG. 3 is the same shape as the XY plane projection image of the main power generation second layer 200 shown in FIG. 3, and the entire area of the lower surface of the main power generation first layer 100 is joined to the entire area of the upper surface of the main power generation second layer 200. Yes. Therefore, as with the main power generation first layer 100, the four portions 210, 220, 230, and 240 can be defined for the main power generation second layer 200 as well. Each part is constituted by a flat layer arranged along a plane parallel to the XY plane. Of course, in practice, the main power generation second layer 200 is a single plate-like integrated structure having an “E” shape, and the above four parts are formed of individual plate-like integrated structures. This is for convenience for explanation by dividing into sections.

  First, the portion 210 is a portion that is arranged on the Y-axis and has a flexible bridge structure. Here, the portion 210 is referred to as a plate-like bridge portion 210. The plate-like bridge portion 210 is a thin beam-like structure extending from the origin O to the tip point T (one point on the Y axis) along the Y axis, and has flexibility, so that It has the property of deforming in any direction. Here, for convenience of explanation, the vicinity of the origin O of the plate-like bridge portion 210 is called a root end portion, and the vicinity of the tip point T is called a tip end portion. The plate-like bridge portion 210 is an elongated plate-like member that extends along the Y axis from the root end portion to the tip end portion.

  Here, the root end portion (near the origin O) of the plate-like bridge portion 210 is joined and supported and fixed to a pedestal 400 (not shown in FIG. 3). Therefore, if the pedestal 400 is fixed to the apparatus housing or the like, the root end portion is fixed. On the other hand, the front end portion (near the front end point T) of the plate-like bridge portion 210 becomes a free end that can be displaced within the range of the degree of freedom of deformation of the plate-like bridge portion 210.

  The bridge portion piezoelectric layer 110 shown in FIG. 2 is fixed to the upper surface of the plate-like bridge portion 210 shown in FIG. As will be described later, the plate-like bridge portion 210 has a property of causing bending due to vibration of the weight body, and the bending is transmitted to the bridge portion piezoelectric layer 110 fixed to the upper surface thereof, and based on the generated stress. Electric charge is generated.

  On the other hand, the portions 220, 230, and 240 (the portion of the main power generation second layer 200 excluding the plate-like bridge portion 210) are collectively referred to as a weight support portion here. As shown in the figure, the weight body support portion is connected to the plate-like bridge portion 210 at the tip point T. The role of this weight body support part literally supports the weight body (main power generation third layer 300), and transmits the vibration of the weight body to the tip part (near the tip point T) of the plate-like bridge part 210. There is. In the case of the basic embodiment shown here, the weight body support portion is a “U” -shaped member having a central plate-like portion 220, a left wing plate-like portion 230, and a right wing plate-like portion 240.

  The central plate-like portion 220 is an elongated plate-like member disposed on the X ′ axis that is an axis that intersects the Y axis and is parallel to the X axis, and extends along the X ′ axis so as to intersect the Y axis. Yes. The central portion of the central plate-like portion 220 is connected to the tip portion of the plate-like bridge portion 210 at the tip point T. That is, the tip of the plate-like bridge portion 210 is connected in the vicinity of the portion that intersects the Y axis of the central plate-like portion 220. As a result, the XY plane projection images of the plate-like bridge portion 210 and the central plate-like portion 220 are T-shaped. The central piezoelectric layer 120 shown in FIG. 2 is fixed to the upper surface of the central plate-like portion 220 shown in FIG.

  On the other hand, the left wing plate-like portion 230 is a plate-like member extending from the left side of the central plate-like portion 220 to the left side of the plate-like bridge portion 210 along the direction parallel to the Y axis, and the right wing plate-like portion 240 is The plate-like member extends from the right side of the plate-like portion 220 to the right side of the plate-like bridge portion 210 along a direction parallel to the Y-axis. The left wing piezoelectric layer 130 shown in FIG. 2 is fixed to the upper surface of the left wing plate-like portion 230 shown in FIG. 3, and the right wing piezoelectric layer 140 shown in FIG. 2 is fixed to the upper surface of the right wing plate-like portion 240 shown in FIG. .

  In FIG. 3, the lower end (root end portion) of the plate-like bridge portion 210 extends downward as compared with the lower end of the left wing plate-like portion 230 and the lower end of the right wing plate-like portion 240. This is because the root end portion (near the origin O) of the plate-like bridge portion 210 is connected to the base 400 as shown in the perspective view of FIG. The stress applied to the plate-like bridge portion 210 due to the vibration of the weight body is concentrated at the root end portion (near the connection end with the base 400) and the tip portion (near the connection end with the central plate portion 220).

  4 is a top view of the main power generation third layer 300 of the main power generation structure MGS shown in FIG. 1, and a two-dimensional plan view in which the X axis is the right direction of the figure and the Y axis is the upward direction of the figure. It is shown. The X axis, Y axis, and origin O shown in FIG. 4 are actually located above the main power generation third layer 300. The main power generation third layer 300 is connected to the lower surfaces of the weight support portions 220, 230, and 240 shown in FIG. 3, and is sufficient to cause the plate-like bridge portion 210 to bend based on the applied acceleration. It functions as a weight body with mass. The weight body vibrates due to the action of force based on acceleration applied from the outside, and plays a role in causing the plate-like bridge portion 210 to undergo elastic deformation that varies with time.

  In the case of the basic embodiment shown here, the main power generation third layer 300 (weight body) is configured by a central weight portion 320, a left wing weight portion 330, and a right wing weight portion 340, as shown in FIG. Yes. The central weight portion 320 is an elongated portion extending along the X ′ axis (an axis that intersects the Y axis and is parallel to the X axis), and plays a role of connecting the left wing weight portion 330 and the right wing weight portion 340. .

  Further, as described above, if the side where the X coordinate value is negative is defined as the left side and the side where the X coordinate value is positive is defined as the right side on both sides of the plate-like bridge portion 210, the left wing weight portion 330. Is a weight body extending to the left side of the plate-like bridge portion 210 along the direction parallel to the Y axis from the left side of the central weight portion 320, and the right wing weight portion 340 is from the right side of the central weight portion 320. The weight body extends to the right side of the plate-like bridge portion 210 along the direction parallel to the Y axis.

  4 is fixed to the lower surface of the central plate portion 220 shown in FIG. 3, and the left wing weight portion 330 shown in FIG. 4 is fixed to the lower surface of the left wing plate portion 230 shown in FIG. 4 is fixed to the lower surface of the right wing plate-like portion 240 shown in FIG. Eventually, the XY plane projection image of the weight body having the left wing weight portion 330, the center weight portion 320, and the right wing weight portion 340 has a “U” shape. In the main power generation third layer 300, a cavity 310 is formed at a position immediately below the plate-like bridge portion 210. Due to the presence of the hollow portion 310, the plate-like bridge portion 210 can be displaced downward (Z-axis negative direction).

  Actually, the main power generation third layer 300 is an integral structure having a “U” shape, and the above three portions are provided for convenience of description of the integral structure divided into individual sections. belongs to.

  FIG. 5 is a side view of the main power generation structure MGS shown in FIG. As described above, in practice, the main power generation first layer 100, the main power generation second layer 200, and the main power generation third layer 300 shown in FIG. 1 are joined to each other in a stacked state in the vertical direction. Configure. For bonding the layers, for example, adhesion using an adhesive may be performed (as will be described later, layers can be formed by printing, vapor deposition, sputtering, or the like). FIG. 5 is a side view when the main power generation structure MGS in such a stacked state is observed from the X-axis negative direction toward the X-axis positive direction. Therefore, the origin O of the coordinate system is located at the right end of the figure, and the vertical direction in the drawing is the X axis positive direction, the left direction of the figure is the Y axis positive direction, and the upward direction of the figure is the Z axis positive direction.

  In FIG. 5, the root portion of the plate-like bridge portion 210 is shown in the vicinity of the origin O in the portion of the main power generation second layer 200, and the central plate-like portion located in front of this plate-like bridge portion 210. 220 and the left wing plate-like portion 230 are observed. In the portion of the main power generation first layer 100 located above the main power generation second layer 200, the bridge portion piezoelectric layer 110, the central piezoelectric layer 120, and the left wing piezoelectric layer 130 are observed on the upper surface of the lower layer electrode E0. Upper layer electrodes E1 and E3 are observed on the upper surface (the upper layer electrodes E2 and E4 are hidden behind them). Further, as the portion of the main power generation third layer 300 located below the main power generation second layer 200, a central weight portion 320 and a left wing weight portion 330 are observed. The right end portion (near the origin O) of the bridge portion piezoelectric layer 110 and the plate-like bridge portion 210 protruding to the right side of the figure is fixed to a pedestal 400 (not shown).

  As illustrated, the main power generation first layer 100 constitutes a piezoelectric element (piezoelectric material layer 105 and upper and lower electrodes) formed so as to cover the upper surface of the main power generation second layer 200. Below the main power generation second layer 200, a main power generation third layer 300 (a body having a “U” shape) is joined, and the weight body is displaced based on the applied acceleration. The main power generation second layer 200 (particularly, the plate-like bridge portion 210) is bent, and the main power generation first layer 100 (particularly, the bridge portion piezoelectric layer 110) formed on the upper surface thereof is also bent. Is transmitted, and electric charges are generated in the upper layer electrodes E1 to E4 and the lower layer electrode E0.

  FIG. 6 is a top view showing a state where the main power generation structure MGS shown in FIG. The hatching in the figure is for showing the fixed state by the formation region of each upper electrode and the pedestal, and does not show a cross section. Moreover, the code | symbol of parenthesis has shown the component arrange | positioned below. Here, when attention is paid to the planar shape of the four upper layer electrodes E1 to E4 arranged on the upper surface of the bridge portion piezoelectric layer 110, all of them are elongated rectangular electrodes extending in the Y-axis direction.

  When attention is paid to the arrangement of the four upper layer electrodes E1 to E4, the upper ends of the upper layer electrodes E1 and E2 are aligned at the boundary line H (the boundary line between the bridge piezoelectric layer 110 and the central piezoelectric layer 120). The upper electrodes E3 and E4 are arranged at positions where the lower ends thereof are aligned with the lower ends of the bridge portion piezoelectric layer 110 (positions aligned with the X axis). The upper layer electrodes E1 and E3 are disposed on the left side of the bridge portion piezoelectric layer 110 (where the X coordinate value is negative), and the upper layer electrodes E2 and E4 are on the right side of the bridge portion piezoelectric layer 110 (where the X coordinate value is positive). Is located).

  Such shapes and arrangement of the upper layer electrodes E1 to E4 are convenient for efficient power generation as described in §2. Below the “U” -shaped portion (the center piezoelectric layer 120, the left wing piezoelectric layer 130, and the right wing piezoelectric layer 140) shown in FIG. 220, left wing plate-like portion 230, right wing plate-like portion 240) and a weight body (main power generation third layer: central weight portion 320, left wing weight portion 330, right wing weight portion 340). When the force based on the vibration of the weight body acts in the vicinity of the tip point T (see FIG. 7 described later), the bridge portion piezoelectric layer 110 bends together with the plate-like bridge portion 210 that is the support layer. Accordingly, electric charges are generated in the upper layer electrodes E1 to E4 according to the bending. The electrode arrangement shown in the figure is suitable for efficiently performing such charge generation (details will be described in Section 2). Thus, the current generated based on the charge generated by the main power generation structure MGS is rectified by the power generation circuit 500 and extracted as power.

  FIG. 7 is a side sectional view showing a state in which the main power generation structure MGS shown in FIG. 1 is fixed to the pedestal 400, and corresponds to a cross section of the main power generation structure MGS shown in FIG. 6 cut along a central YZ plane.

  In this side cross-sectional view, the main power generation second layer 200 includes a cross section of the plate-like bridge portion 210 from the origin O (root end portion) to the tip point T (tip end portion) and the central plate-like portion 220. Has been. In addition, the main power generation first layer 100 includes a bridge piezoelectric layer 110, a central piezoelectric layer 120, a cross section of the lower layer electrode E0, and side surfaces of the upper layer electrodes E2 and E4.

  In the main power generation third layer 300 (weight body), a cross section of the central weight portion 320 and a side surface of the right wing weight portion 340 are shown. A cavity portion 310 is formed in front of the right wing weight portion 340, and the plate-like bridge portion 210 can be displaced downward due to the presence of the cavity portion 310.

  In the case of the illustrated embodiment, both the root end portion of the plate-like bridge portion 210 and the root end portion of the bridge portion piezoelectric layer 110 are joined and supported and fixed to the pedestal 400. As long as at least the root end portion of the plate-like bridge portion 210 is supported and fixed. In short, it is sufficient that the weight body is supported by the cantilever structure with respect to the pedestal 400 and is suspended from the plate-like bridge portion 210.

  Further, in the present application, the dimensional ratios of the respective parts in the drawings are not necessarily the same as the actual product dimensional ratios. For convenience, the drawings are drawn ignoring the actual dimensional ratios. Therefore, in FIG. 6 and FIG. 7, the actual dimensions of each part are indicated by reference numerals d1 to d10 for reference. The values of these actual dimensions d1 to d10 can be set to the following values, for example, as long as they constitute the power generation element PGE having the MEMS structure. Of course, the following dimension examples are presented as examples, and the dimensions of each part are not limited to the following dimension values in carrying out the present invention.

  d1 = 1000 μm, d2 = 200 μm, d3 = 800 μm, d4 = 100 μm, d5 = 50 μm, d6 = 200 μm, d7 = 70 μm, d8 (thickness of the piezoelectric material layer 105) = 2 μm (preferably 2 μm or more in practice), d9 (Thickness of main power generation second layer 200) = 200 μm, d10 (thickness of main power generation third layer 300) = 1000 μm. The thickness of the lower layer electrode E0 and the upper layer electrodes E1 to E4 is 0.01 μm.

  Generally, the most efficient power generation is possible when the resonance frequency of the weight body determined based on the unique structure of the main power generation structure MGS matches the vibration frequency given from the outside. Therefore, when the frequency of vibration given from the outside is assumed in advance, at the stage of the structural design of the main power generation structure MGS, the design in which the resonance frequency matches the assumed frequency, that is, the dimensions of the above-described parts. It is preferable to perform a design set to an appropriate value.

  In general, the frequency of vibrations generated in transportation equipment such as automobiles, trains, ships, and industrial equipment using motors is often in the range of several Hz to several hundred Hz, and particularly in the range of 10 Hz to 50 Hz. In many cases. Therefore, when it is assumed that power generation is performed by mounting on such a general device, the design is made such that the resonance frequency in the direction of each coordinate axis of the main power generation structure MGS is in the range of 10 Hz to 50 Hz. Is preferred.

  In the above description, for convenience, only the main power generation third layer 300 is referred to as a weight body, but actually, among the components of the main power generation structure MGS, the bridge portion piezoelectric layer 110 and the plate. All of the portions except for the bridge portion 210 serve as a weight body as a whole and have a function of causing displacement at the tip point T. For example, the central piezoelectric layer 120, the left wing piezoelectric layer 130, the right wing piezoelectric layer 140 (components of the main power generation first layer 100) shown in FIG. 6, the central plate portion 220, the left wing plate portion bonded to these lower layers, and the like. 230 and the right wing plate-like portion 240 (components of the main power generation second layer 200) also contribute to the role of causing displacement at the tip point T, and thus function as a part of the weight body.

  However, as shown in FIG. 7, the thickness of the main power generation third layer 300 is set larger than the thickness of the main power generation first layer 100 and the main power generation second layer 200, and the role as the weight body is The main power generation third layer 300 is mainly responsible. Therefore, here, for convenience, the portion of the main power generation third layer 300 is referred to as a weight body.

  The power generating element PGE according to the present invention is characterized in that weight bodies are arranged on both the left and right sides of the plate-like bridge portion 210 constituting the main power generating structure MGS. That is, as is clear from the perspective view of FIG. 1, the weight of the power generating element PGE according to the present invention is at least of the plate-like bridge portion 210 as is clear from the projected image on the XY plane. A left wing weight portion 330 located on the left side and a right wing weight portion 340 located on the right side of the plate-like bridge portion 210 are provided. For this reason, the external force which bends in various directions with respect to the plate-shaped bridge part 210 can be transmitted efficiently. Further, as described in detail in §3, when excessive vibration is applied by providing a member that restricts displacement of the left wing weight portion 330 and the right wing weight portion 340 outside the main power generation structure MGS. In addition, the displacement of the plate-like bridge portion 210 can be limited, and the plate-like bridge portion can be prevented from being damaged.

  Further, in the basic embodiment shown here, the plate-like bridge portion 210 is constituted by the main power generation second layer 200, and the weight body is constituted by the main power generation third layer 300 disposed below, The center of gravity G of the weight body (the structure constituting the main power generation third layer) is located below the plate-like bridge portion 210 at a predetermined distance. 6 and 7, the center of gravity G of the weight body is indicated by x. As described above, when a structure in which the gravity center G of the weight body is disposed at a predetermined distance below the plate-like bridge portion 210 as the main power generation structure MGS, each coordinate axis of acceleration acting on the weight body is adopted. Based on the direction component, the plate-like bridge portion 210 can be flexed efficiently, and efficient power generation becomes possible. In particular, the distance between the center of gravity G and the lower surface of the plate-like bridge portion 210 is preferably as long as possible in order to increase the deflection of the plate-like bridge portion 210 with respect to the acceleration in the Y-axis direction.

  In the case of the example shown here, the main power generation structure MGS has a plane-symmetric structure with respect to the YZ plane, so that the center of gravity of the structure (weight body) constituting the main power generation third layer 300 has a plate shape. It is located on the YZ plane below the bridge part 210. Employing such a symmetrical structure makes it possible to stably vibrate the weight body in the direction of each coordinate axis, which is preferable for improving power generation efficiency.

  The material of each layer constituting the main power generation structure MGS may be any material as long as the material can function as each layer described above, but here, some examples of practically preferable materials are possible. I will list them.

  First, the main power generation first layer 100 only needs to be able to function as a piezoelectric element that generates an electric charge based on externally applied stress. Therefore, the main power generation first layer 100 is polarized in the thickness direction by the action of stress that expands and contracts in the layer direction. It is only necessary that electrodes be formed on both the upper and lower surfaces of the piezoelectric material layer 105 having the properties to be generated. Specifically, the piezoelectric material layer 105 can be constituted by a piezoelectric thin film such as PZT (lead zirconate titanate) or KNN (potassium sodium niobate). Alternatively, a bulk type piezoelectric element may be used. Each of the electrodes E0 to E4 may be made of any material as long as it is a conductive material, but in practice, it may be made of a metal layer such as gold, platinum, aluminum, or copper.

  On the other hand, the main power generation second layer 200 functions as a support substrate for the main power generation first layer 100, and the plate-like bridge portion 210 needs to have flexibility. Silicon is the most suitable material for such applications. Therefore, in the embodiment described here, the main power generation second layer is formed of a silicon substrate. In the case of the example shown in FIG. 7, the thickness d9 of the main power generation second layer 200 is 200 μm, and the plate-like bridge portion 210 made of silicon having such a thickness is sufficiently flexible to generate power. It has sex.

  Of course, it is also possible to use a metal substrate as the main power generation second layer 200. In this case, since the upper layer portion of the metal substrate serves as the lower layer electrode E0, a piezoelectric thin film is formed on the metal substrate by a sputtering method or a sol-gel method. An element can be formed. Alternatively, it is possible to bond a bulk type piezoelectric material on a metal substrate. The upper layer electrode can be formed by printing, vapor deposition, sputtering, or the like using a metal material.

  However, the present inventor believes that the silicon substrate is an optimal material for the main power generation second layer 200 at the present time. In general, when the piezoelectric element is formed on the upper surface of the metal substrate and the piezoelectric element is formed on the upper surface of the silicon substrate by the current manufacturing process, the latter piezoelectric element is compared with the former piezoelectric constant. This is because the constant is about three times larger, and the power generation efficiency of the latter is overwhelmingly higher. This is presumably because the crystal orientation of the piezoelectric element is aligned when the piezoelectric element is formed on the upper surface of the silicon substrate. If a silicon substrate is used as the main power generation second layer 200, the power generation circuit 500 can be configured using a semiconductor element formed on the silicon substrate.

  Since the main power generation third layer 300 is a component that functions as a weight body, it is preferable to use a material having a specific gravity as large as possible. Specifically, a metal substrate such as SUS (iron), copper, or tungsten, or a ceramic substrate or a glass substrate may be used.

<<< §2. Power generation operation of power generation element according to basic embodiment >>
Subsequently, the power generation operation of the power generation element PGE according to the basic embodiment described in §1 will be described. As described above, the power generation element PGE shown in FIG. 1 is configured by adding the pedestal 400 and the power generation circuit 500 to the main power generation structure MGS composed of a three-layer structure, and in each coordinate axis direction in the XYZ three-dimensional coordinate system. It has a function of generating power by converting vibration energy into electrical energy.

  Therefore, here, the principle of the power generation operation is performed when the pedestal 400 is fixed to the traveling vehicle and vibration components in the coordinate axis directions are applied to the power generation element PGE. To do. Therefore, hereinafter, the operation of the power generation element PGE will be described on the assumption that the XYZ three-dimensional coordinate system is a coordinate system fixed to the pedestal 400 (that is, the transportation device) and the weight body vibrates in the coordinate system. To do.

  FIG. 8 is a top view showing a deformation mode when a force + Fx in the X-axis positive direction acts on the weight body (main power generation third layer 300) of the main power generation structure MGS shown in FIG. Such a phenomenon occurs when the acceleration −αx in the negative direction of the X-axis acts on the pedestal 400 due to the vibration of the automobile traveling on the road surface. That is, when the acceleration −αx acts on the pedestal 400, the acceleration + αx in the opposite direction acts as an inertial force on the weight body. As a result, in the XYZ three-dimensional coordinate system, an external force + Fx that is displaced in the positive direction of the X axis (rightward in the drawing) acts on the weight body as indicated by the white arrow in the drawing.

  The external force + Fx acts as a force for displacing the center of gravity G and the tip point T of the weight body in the right direction in the figure, so that the tip portion of the plate-like bridge portion 210 and the bridge portion piezoelectric layer 110 formed on the upper surface thereof is It is displaced to the right in the figure together with the weight body. On the other hand, since the root end (near the origin O) is fixed to the pedestal 400, it is not displaced on the XYZ three-dimensional coordinate system. As a result, the plate-like bridge portion 210 and the bridge portion piezoelectric layer 110 formed on the upper surface thereof are curved and deformed as shown.

  Such bending deformation causes a stretching stress as illustrated in the direction along the Y axis for each of the arrangement positions of the four upper layer electrodes E1 to E4 of the bridge portion piezoelectric layer 110. That is, compressive stress in the Y-axis direction acts on the arrangement position of the upper layer electrodes E1 and E4 of the bridge portion piezoelectric layer 110 as indicated by the pair of arrows facing vertically (indicated by a circle with a "shrinkage"). As for the arrangement position of the upper layer electrodes E2 and E3 of the bridge portion piezoelectric layer 110, as indicated by the double arrows with arrows above and below, the tensile stress in the Y-axis direction acts (the circle has the shape of “extension”). Show).

  On the other hand, when the acceleration + αx in the X-axis positive direction acts on the pedestal 400, the acceleration −αx in the reverse direction acts as an inertial force on the weight body. As a result, in the XYZ three-dimensional coordinate system, an external force −Fx that is displaced in the negative direction of the X axis (leftward in the figure) acts on the weight body, contrary to FIG. In this case, the expansion / contraction mode of each part is the reverse of that in FIG. That is, an extension stress acts on the arrangement position of the upper layer electrodes E1, E4 of the bridge portion piezoelectric layer 110, and a compressive stress acts on the arrangement position of the upper layer electrodes E2, E3 of the bridge portion piezoelectric layer 110.

  FIG. 9 is a side sectional view showing a deformation mode when a force + Fy in the Y-axis positive direction is applied to the weight body (main power generation third layer 300) of the main power generation structure MGS shown in FIG. Such a phenomenon occurs when the acceleration −αy in the negative Y-axis direction acts on the pedestal 400 due to the vibration of the automobile traveling on the road surface. That is, when the acceleration −αy acts on the pedestal 400, the acceleration + αy in the reverse direction acts on the weight body as an inertial force. As a result, in the XYZ three-dimensional coordinate system, an external force + Fy that is displaced in the positive Y-axis direction (left direction in the figure) acts on the weight body as indicated by the white arrow in the figure.

  The external force + Fy acts as a force for displacing the center of gravity G of the weight body in the left direction of the figure. However, since the weight body is connected in the vicinity of the tip point T of the plate-like bridge portion 210, the weight body 9 is inclined obliquely as shown in FIG. 9 (in FIG. 9, the left side is raised and the right side is lowered). Therefore, the plate-like bridge portion 210 and the bridge portion piezoelectric layer 110 formed on the upper surface thereof are curved and deformed to warp upward as shown in FIG.

  Such bending deformation causes a stretching stress as illustrated in the direction along the Y axis for each of the arrangement positions of the four upper layer electrodes E1 to E4 of the bridge portion piezoelectric layer 110. That is, compressive stress in the Y-axis direction acts on all the positions of the four upper layer electrodes E1 to E4 formed on the upper surface of the bridge portion piezoelectric layer 110, as indicated by a pair of arrows facing left and right. Is indicated by the word “shrink”).

  On the other hand, when the acceleration + αy in the Y-axis positive direction acts on the pedestal 400, the acceleration −αy in the reverse direction acts as an inertial force on the weight body. As a result, in the XYZ three-dimensional coordinate system, an external force -Fy that is displaced in the negative Y-axis direction (the right direction in the figure) acts on the weight body, contrary to FIG. In this case, the weight body inclines in a manner opposite to that in FIG. 9 (the left side is lowered and the right side is raised), and the manner of expansion and contraction of each part is reversed from that in FIG. That is, the tensile stress in the Y-axis direction acts on all of the arrangement positions of the four upper layer electrodes E1 to E4 formed on the upper surface of the bridge portion piezoelectric layer 110.

  FIG. 10 is a side sectional view showing a deformation mode when a force + Fz in the positive direction of the Z-axis acts on the weight body (main power generation third layer 300) of the main power generation structure MGS shown in FIG. Such a phenomenon occurs when the acceleration −αz in the negative Z-axis direction acts on the pedestal 400 due to the vibration of the automobile traveling on the road surface. That is, when the acceleration −αz acts on the pedestal 400, an acceleration + αz in the reverse direction acts on the weight body as an inertial force. As a result, in the XYZ three-dimensional coordinate system, an external force + Fz that is displaced in the positive direction of the Z-axis (upward in the figure) acts on the weight body as indicated by the white arrow in the figure.

  The external force + Fz acts as a force for displacing the center of gravity G of the weight body in the upward direction in the figure. However, since the weight body is connected in the vicinity of the tip point T of the plate-like bridge portion 210, the plate-like bridge is used. A force for displacing the tip of the portion 210 upward in the drawing is applied. On the other hand, the root end portion (near the origin O) of the plate-like bridge portion 210 is fixed to the pedestal 400. Therefore, in the XYZ three-dimensional coordinate system, a force is applied to move the tip portion upward while the root end portion of the plate-like bridge portion 210 is fixed, and the plate-like bridge portion 210 and its upper surface are formed. The bridge piezoelectric layer 110 is curved and deformed as shown in FIG.

  Such bending deformation causes a stretching stress as illustrated in the direction along the Y axis for each of the arrangement positions of the four upper layer electrodes E1 to E4 of the bridge portion piezoelectric layer 110. That is, as shown by the double arrows with arrows on the left and right, the extension stress in the Y-axis direction acts on the positions of the upper layer electrodes E1 and E2 disposed at the tip of the bridge portion piezoelectric layer 110 (rounded). (Indicated by the word “extension”). On the other hand, the compressive stress in the Y-axis direction acts on the positions of the upper layer electrodes E3 and E4 arranged at the root end of the bridge portion piezoelectric layer 110 as shown by the pair of arrows facing left and right (round) Is indicated by the word “shrink”).

  On the other hand, when the acceleration + αz in the Z-axis positive direction acts on the pedestal 400, the acceleration −αz in the reverse direction acts as an inertial force on the weight body. As a result, in the XYZ three-dimensional coordinate system, an external force -Fz that is displaced in the negative Z-axis direction (downward in the figure) acts on the weight body, contrary to FIG. In this case, since the weight body moves downward in the figure, the expansion / contraction mode of each part is reversed from that in FIG. That is, a compressive stress acts on the arrangement position of the upper layer electrodes E1 and E2 of the bridge portion piezoelectric layer 110, and an extension stress acts on the arrangement position of the upper layer electrodes E3 and E4 of the bridge portion piezoelectric layer 110.

  11 is based on the deformation modes of FIGS. 8 to 10, and when the force in each coordinate axis direction acts on the weight body of the main power generation structure MGS shown in FIG. 1, the upper layer electrode E <b> 1 of the bridge portion piezoelectric layer 110. It is a table | surface which shows the expansion-contraction stress about the Y-axis direction added to the position of -E4. The figure is a table showing the stretching stress when force + Fx, + Fy, + Fz in the positive direction of each coordinate axis is applied. The stretching stress when force -Fx, -Fy, -Fz in the negative direction of each coordinate axis is applied is shown in the table. In this table, the compression / decompression relationship is reversed.

  As described in §1, in the power generation element PGE according to the basic embodiment, the main power generation first layer 100 includes the lower layer electrode E0 formed in a layer shape on the surface of the main power generation second layer 200, and the lower layer electrode E0. A piezoelectric element having a piezoelectric material layer 105 formed in a layer on the surface of the piezoelectric material layer and an upper electrode group consisting of a plurality of upper layer electrodes E1 to E4 locally formed on the surface of the piezoelectric material layer 105 is configured. The piezoelectric material layer 105 has a property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction.

  Here, when a stress extending in the layer direction is applied to the piezoelectric material layer 105, a positive charge is generated upward, a negative charge is generated downward, and a stress compressing in the layer direction is applied. Assuming that a material having a polarization characteristic that generates electric charge is used, when the force + Fx, + Fy, + Fz in the positive direction of each coordinate axis acts on the weight body, the polarity of the electric charge generated in the upper layer electrodes E1 to E4 is shown in FIG. It looks like the table. In other words, the table of FIG. 12 is obtained by replacing “decompression” with “+” and “compression” with “−” in the table of FIG. The stretching stress when the forces -Fx, -Fy, -Fz in the negative direction of each coordinate axis are applied is the reverse of the +/- relationship in this table.

  Of course, the piezoelectric material layer 105 generates a negative charge upward and a downward positive charge when a stress extending in the layer direction acts, and a positive charge upward and a negative charge downward when a stress compressing in the layer direction acts. It is also possible to use one having a polarization characteristic that generates electric charges. When a piezoelectric material layer having such polarization characteristics is used, the +/− relationship is reversed with respect to the case described above. Further, when a bulk type piezoelectric element is used, it is possible to dispose piezoelectric elements having different polarization characteristics for each region, and each of the local piezoelectric elements P1 to P4 has an arbitrary polarization characteristic. Can be provided.

  In any case, the power generation circuit 500 can extract electric power by rectifying the current generated based on the charges generated in the four localized upper layer electrodes E1 to E4 and the one common lower layer electrode E0.

  As shown in the top view of FIG. 6, the four upper layer electrodes E <b> 1 to E <b> 4 are arranged at respective unique positions on the upper surface of the bridge portion piezoelectric layer 110. Here, according to each arrangement position, these four upper layer electrode groups are divided into a tip left upper layer electrode E1, a tip right upper layer electrode E2, a root left upper layer electrode E3, and a root right upper layer electrode E4. I will call it. Then, the projection image of the upper left electrode layer E1 on the upper surface of the main power generation second layer 200 extends in a direction parallel to the Y axis, and the X coordinate value in the vicinity of the distal end portion of the plate-like bridge portion 210 is negative. The projected image of the upper right electrode layer E2 on the upper surface of the main power generation second layer 200 extends in the direction parallel to the Y axis, and the X coordinate value near the front end portion of the plate-like bridge portion 210 is positive. The projection image of the upper left electrode layer E3 on the upper surface of the main power generation second layer 200 extends in a direction parallel to the Y axis, and the X coordinate value in the vicinity of the root end portion of the plate-like bridge portion 210 is negative. The projected image of the root end right upper layer electrode E4 on the upper surface of the main power generation second layer 200 extends in the direction parallel to the Y axis, and the X coordinate near the root end of the plate-like bridge portion 210 Located on the side where the value is positive.

  Such a unique arrangement of the four upper layer electrodes E1 to E4 is suitable for efficiently generating electric charges, and is effective for increasing the power generation efficiency. This is because, even when a force in any coordinate axis direction acts on the weight body, a large stress is generated in the four arrangement positions in the Y axis direction. This is apparent from the stress distribution diagrams shown in FIGS. These stress distribution diagrams show the results of FEM (finite element method) structural analysis by a computer using the actual dimensions described in §1, and the root end portion of the plate-like bridge portion 210 is fixed. In FIG. 5, the Y-axis direction stress distribution generated in the piezoelectric material layer 105 when a force in the positive direction of a specific coordinate axis acts on the weight body is shown.

  FIG. 13 is a stress distribution diagram showing the Y-axis direction stress generated in the piezoelectric material layer 105 when a force + Fx in the X-axis positive direction acts on the weight body of the main power generation structure MGS shown in FIG. In this figure, it can be seen that basically a stress distribution based on the expansion and contraction mode shown in FIG. 8 is obtained. The unique arrangement of the four upper layer electrodes E1 to E4 corresponds to a position where significant stress is generated in such a stress distribution diagram.

  FIG. 14 is a stress distribution diagram showing the Y-axis direction stress generated in the piezoelectric material layer 105 when the force + Fy in the Y-axis positive direction acts on the weight body of the main power generation structure MGS shown in FIG. As can be seen from the deformation mode shown in FIG. 9, when the force + Fy is applied, a compressive stress in the Y-axis direction is applied over almost the entire region of the bridge portion piezoelectric layer 110. For this reason, the stress distribution diagram shown in FIG. 14 also shows that a strong compressive stress is generated over almost the entire region of the bridge portion piezoelectric layer 110. The unique arrangement of the four upper layer electrodes E1 to E4 corresponds to the position where significant stress is generated in such a stress distribution diagram.

  FIG. 15 is a stress distribution diagram showing the Y-axis direction stress generated in the piezoelectric material layer 105 when the Z-axis positive force + Fz is applied to the weight body of the main power generation structure MGS shown in FIG. In this figure, it can be seen that basically a stress distribution based on the expansion and contraction mode shown in FIG. 10 is obtained. The unique arrangement of the four upper layer electrodes E1 to E4 corresponds to the position where significant stress is generated in such a stress distribution diagram.

  As described above, when the stress distribution diagrams shown in FIGS. 13 to 15 are seen, the four upper electrodes E1 to E4 shown in FIG. 6 are regions where stress is concentrated when the weight body is displaced in any direction. It can be seen that the generated charges can be collected effectively. Referring to these stress distribution diagrams, the upper end position of the upper layer electrodes E1 and E2 shown in FIG. 6 may extend slightly above the boundary line H (Y-axis positive direction). I understand.

  As described above, the stress distribution in the case where the forces + Fx, + Fy, + Fz in the positive directions of the respective coordinate axes act on the weight body has been described with reference to FIGS. 13 to 15. The forces −Fx, −Fy in the negative directions of the respective coordinate axes have been described. , -Fz acts, the stress distribution is the reverse of the compression / extension distribution. After all, the four upper layer electrodes E1 to E4 shown in the top view of FIG. 6 are arranged at positions where a large stress is generated in the Y-axis direction when any force in the coordinate axis direction acts on the weight body. Will be. In addition, when a force in any coordinate axis direction is applied, a charge having a reverse polarity is not generated on the same electrode. That is, there is no such phenomenon that opposite polarity charges cancel each other out at the same electrode. Therefore, the power generation element PGE employing such a unique electrode arrangement can perform extremely efficient power generation.

  FIG. 16 is a circuit diagram showing a specific configuration of the power generation circuit 500 used in the power generation element PGE shown in FIG. 1, and has a function of rectifying a current generated based on the electric charge generated in the piezoelectric element and extracting power.

  In FIG. 16, the left end piezoelectric element P1 at the tip end is a station constituted by the upper left electrode E1 and the lower layer electrode E0 at the tip end portion shown in FIG. 6 and a portion of the piezoelectric material layer 105 located below the upper layer electrode E1. The right-side piezoelectric element P2 at the front end portion is composed of the upper right electrode E2 and the lower layer electrode E0 shown in FIG. 6 and the portion of the piezoelectric material layer 105 located below the upper electrode E2. 1 shows a localized piezoelectric element.

  Similarly, the root end left side piezoelectric element P3 includes the root end left upper layer electrode E3 and the lower layer electrode E0 shown in FIG. 6, and a portion of the piezoelectric material layer 105 located below the upper layer electrode E3. The root end right piezoelectric element P4 indicates a localized piezoelectric element, the root end right upper layer electrode E4 and the lower layer electrode E0 shown in FIG. 6, and a portion of the piezoelectric material layer 105 positioned below the upper layer electrode E4, The local piezoelectric element comprised by these is shown. Further, E0 indicated by a white circle on the circuit diagram corresponds to the lower layer electrode, and E1 to E4 correspond to the upper layer electrodes.

  D1 (+), D2 (+), D3 (+), and D4 (+) are rectifying elements (diodes) and play a role of taking out positive charges generated in the upper layer electrodes E1, E2, E3, and E4, respectively. D1 (−), D2 (−), D3 (−), and D4 (−) are also rectifying elements (diodes), and play the role of extracting negative charges generated in the upper layer electrodes E1, E2, E3, and E4, respectively. . Similarly, D0 (+) is a rectifier element (diode) that plays a role of taking out positive charges generated in the lower layer electrode E0, and D0 (−) is a rectifier element that plays a role of taking out negative charges generated in the lower layer electrode E0 ( Diode).

  On the other hand, Cf is a smoothing capacitive element (capacitor). The positive charge taken out is supplied to the positive terminal (upper terminal in the figure) and the negative charge taken out to the negative terminal (lower terminal in the figure). Is supplied. The capacitive element Cf plays a role of smoothing the pulsating flow based on the generated charge, and the impedance of the capacitive element Cf can be almost ignored at the steady time when the vibration of the weight body is stable. ZL connected in parallel to the capacitive element Cf indicates the load of the device that receives the supply of power generated by the power generation element PGE.

  Eventually, the power generation circuit 500 includes the smoothing capacitive element Cf and the positive electrode of the capacitive element Cf from each upper layer electrode E1 to E4 in order to guide the positive charge generated in each upper layer electrode E1 to E4 to the positive side of the capacitive element Cf. The positive charge rectifying elements D1 (+), D2 (+), D3 (+), D4 (+) whose forward direction is the direction toward the side, and the negative charges generated in the upper layer electrodes E1 to E4 are capacitive elements Cf Negative charge rectifying elements D1 (−), D2 (−), D3 (−), D4 () in which the direction from the negative electrode side of the capacitive element Cf toward the upper layer electrodes E1 to E4 is the forward direction. -), And the electric energy converted from vibration energy is smoothed and supplied by the capacitive element Cf.

  In this circuit diagram, a load ZL includes positive charges extracted by positive charge rectifiers D1 (+), D2 (+), D3 (+), and D4 (+), and negative charge rectifiers D1 (− ), D2 (−), D3 (−), and D4 (−), and negative charges extracted by D4 (−) are supplied. Therefore, in principle, the most efficient power generation is possible if the total amount of positive charges and the total amount of negative charges generated at the upper layer electrodes E1 to E4 are equal at each moment.

  As shown in FIG. 6, the main power generation structure MGS according to the basic embodiment has a symmetrical structure that is plane-symmetric with respect to the YZ plane. If such a symmetric structure is adopted, as shown in FIG. 8, when the weight body vibrates in the X-axis direction, the total amount of positive charges and negative charges generated in the pair of upper layer electrodes arranged at the symmetric positions. The total amount of electricity is almost equal, and efficient power generation can be expected. Also, there is symmetry with respect to the longitudinal center position of the bridge portion piezoelectric layer 110 between the tip electrode group composed of the upper layer electrodes E1 and E2 and the root end electrode group composed of the upper layer electrodes E3 and E4. . Therefore, as shown in FIG. 10, even when the weight body vibrates in the Z-axis direction, the total amount of positive charges and the total amount of negative charges generated in the upper electrodes E1 to E4 are substantially equal, which is efficient. Power generation can be expected.

<<< §3. Displacement limiting structure and power generation device >>
In the main power generation structure MGS shown in FIG. 1, in order to increase the power generation efficiency, the plate-like bridge portion 210 is preferably as thin and long as possible. The first reason is that if the thin and long plate-like bridge portion 210 is used, the flexibility is increased, so that a larger deflection is generated. If large bending occurs in the plate-like bridge portion 210, large deformation also occurs in the piezoelectric material layer 105, and the power generation amount increases. Note that, if the width of the plate-like bridge portion 210 is reduced, a merit that causes a large deflection is obtained, but since the area of the piezoelectric material layer 105 is reduced, a demerit that a power generation amount is reduced is caused.

  The second reason why the plate-like bridge portion 210 is made thin and long is to obtain an appropriate resonance frequency. As described above, the resonance frequency of the weight body determined based on the specific structure of the main power generation structure MGS is preferably matched with the vibration frequency in the usage environment (transport equipment, industrial equipment, etc.) of the power generation element. Above, it is preferable to design so that the resonance frequency is in the range of 10 Hz to 50 Hz. In order to design the main power generation structure MGS having a resonance frequency in such a range, it is advantageous to make the plate-like bridge portion 210 thin and long.

  For this reason, when designing the power generating element PGE according to the present invention, it is preferable to make the plate-like bridge portion 210 thin and long. However, the thin and long plate-like bridge portion 210 is easily damaged when an excessive external force is applied. For example, FIG. 8 shows a deformation mode of the main power generation structure MGS when the force + Fx in the positive direction of the X axis acts on the weight body, but excessive force + Fx (excessive acceleration−αx) is shown. If it acts, excessive deformation may occur in the bridge portion piezoelectric layer 110 and the plate-like bridge portion 210 below the bridge portion piezoelectric layer 110 and may be damaged.

  In the case of the main power generation structure MGS adopted in the present invention, a displacement limiting structure that suppresses excessive displacement of the plate-like bridge portion 210 can be easily added. This is because the weight body has a left wing weight portion located on the left side of the plate-like bridge portion and a right wing weight portion located on the right side. For example, in the embodiment shown in FIG. 6, the left wing weight portion 330 is disposed below the left wing piezoelectric layer 130, and the right wing weight portion 340 is disposed below the right wing piezoelectric layer 140. The plate-like bridge portion 210 located below the layer 110 is protected from the left and right by the left wing weight portion 330 and the right wing weight portion 340.

  Therefore, if any displacement restriction walls are provided on the right and left sides of the main power generation structure MGS shown in FIG. 6, the displacement of the weight body can be restricted by the displacement restriction walls. For example, when the force + Fx in the X-axis positive direction is applied to the weight body as in the example of FIG. 8, the weight body cannot be displaced beyond the right displacement limiting wall. Similarly, when force -Fx in the negative direction of the X-axis acts on the weight body, the weight body cannot be displaced beyond the left displacement limiting wall.

  In the case of the embodiment shown in FIG. 6, the central weight portion 320 is disposed below the central piezoelectric layer 120. Therefore, if a displacement limiting wall is provided also above the drawing, the weight body has Y Even when force + Fy in the positive axial direction is applied, the weight body cannot be displaced beyond the upper displacement limiting wall.

  After all, in the embodiment shown in FIG. 6, the plate-like bridge portion 210 located below the bridge portion piezoelectric layer 110 is surrounded by the “U” -shaped weight body and protected from the surroundings. Therefore, if any displacement limiting wall is provided outside the main power generation structure MGS, excessive displacement of the weight body can be limited and damage to the plate-like bridge portion 210 can be avoided. Since the plate-like bridge portion 210 is surrounded by a “U” -shaped weight body, it does not directly contact the displacement limiting wall.

  As the displacement limiting wall, for example, it is possible to use the inner wall surface of the apparatus housing that accommodates the main power generation structure MGS. However, the gap between the outer surface of the weight body and the inner surface of the displacement limiting wall is an appropriate value (when the weight body moves freely within the range necessary for normal power generation operation and excessive acceleration is applied) In order to set a value suitable for controlling the displacement of the weight body only, it is preferable to provide a dedicated displacement limiting wall. Therefore, here, an embodiment in which the base 400 is used as a displacement limiting wall will be described.

  In the power generating element PGE according to the present invention, the root end portion of the plate-like bridge portion 210 is fixed to the pedestal 400. For example, in FIG. 1, a pedestal 400 is shown as a mere symbol sign indicating a fixed part. Moreover, in FIGS. 6-10, the base 400 is shown as a mere fixed surface. Actually, the pedestal 400 may have any structure as long as the base end portion of the plate-like bridge portion 210 can be fixed and the weight body can be suspended. The embodiment described below is an example in which an annular structure surrounding the main power generation structure MGS is used as the base 400 and the inner wall of the annular structure is used as a displacement limiting wall.

  FIG. 17 is a top view showing a power generation element PGE using a rectangular annular structure as the pedestal 400 (actually, only the part of the power generation element structure excluding the power generation circuit 500 from the power generation element PGE is shown). The power generation circuit 500 is not shown). The main power generation structure MGS drawn in the center of the drawing is the main power generation structure according to the basic embodiment described in §1 and §2, and a rectangular-shaped annular structure disposed around the main power generation structure is a pedestal. 400. Main power generation structure MGS and pedestal 400 are joined at the position of origin O.

  The pedestal 400 forms an annular structure that surrounds the main power generation structure MGS along the XY plane. More specifically, the pedestal 400 is configured by a rectangular-shaped annular structure having four sets of wall portions including a first wall portion 410, a second wall portion 420, a third wall portion 430, and a fourth wall portion 440. Has been. Here, the first wall portion 410 is disposed adjacent to the main power generation structure MGS on the X-axis negative direction side, constitutes a wall surface along a plane parallel to the YZ plane, and the second wall portion 420 is the main wall structure. The third wall portion 430 is disposed adjacent to the power generation structure MGS on the X-axis positive direction side and forms a wall surface along a plane parallel to the YZ plane. The third wall portion 430 is in the Y-axis positive direction with respect to the main power generation structure MGS. The fourth wall portion 440 is arranged adjacent to the main power generation structure MGS on the Y axis negative direction side and is parallel to the XZ plane. It constitutes the wall surface along the plane. A root end portion of the plate-like bridge portion 210 that constitutes a part of the main power generation structure MGS is supported and fixed to the inner surface of the fourth wall portion 440.

  When a horizontal component (a component parallel to the XY plane) of acceleration exceeding a predetermined size acts on the power generating element PGE having such a structure, the weight body (main power generation third layer 300) It contacts the inner surface of the base 400 made of an annular structure, and further displacement is limited. As illustrated, a gap dimension d11 is secured between the left side surface of the main power generation structure MGS and the inner surface of the first wall portion 410, and the right side surface of the main power generation structure MGS and the inner surface of the second wall portion 420 are secured. A gap dimension d12 is ensured between them. Similarly, a gap dimension d13 is secured between the upper surface of the main power generation structure MGS and the inner surface of the third wall portion 430, and the lower surface of the main power generation structure MGS and the inner surface of the fourth wall portion 440 are arranged. A gap dimension d14 is secured between them.

  Therefore, even when excessive vibration is applied to the power generation element PGE and an external force component in the X-axis direction acts on the weight body, the displacement of the weight body is limited within the range of the gap dimensions d11 and d12. Even if an external force component in the Y-axis direction is applied to this, the displacement of the weight body is limited to the range of the gap dimensions d13 and d14. For this reason, the extent of the bending which arises in the plate-shaped bridge part 210 can be restrict | limited, and the damage of the plate-shaped bridge part 210 can be prevented.

  The structural relationship between the main power generation structure MGS and the pedestal 400 is shown in detail in the side sectional views shown in FIGS. 18 is a front cross-sectional view showing a cross section of the power generating element PGE shown in FIG. 17 cut along a cutting line 18-18. As described above, the main power generation structure MGS includes a three-layer structure in which the main power generation first layer 100, the main power generation second layer 200, and the main power generation third layer 300 are stacked. On the other hand, the pedestal 400 also includes a three-layer structure in which a pedestal first layer 401, a pedestal second layer 402, and a pedestal third layer 403 are stacked.

  Here, the main power generation first layer 100 and the pedestal first layer 401 are arranged at exactly the same position with respect to the Z axis, and the main power generation second layer 200 and the pedestal second layer 402 are also exactly at the same position with respect to the Z axis. Is arranged. On the other hand, when the main power generation third layer 300 and the pedestal third layer 403 are compared, the upper surface is arranged at the same position with respect to the Z-axis, but the lower surface of the main power generation third layer 300 is the pedestal. It is located slightly above the third layer 403. This is because the weight bodies (the central weight portion 320, the left wing weight portion 330, and the right wing weight portion 340) are suspended from the bottom surface of the base 400.

  As illustrated, a gap d11 is secured between the outer surface of the left wing weight portion 330 and the inner surface of the first wall portion 410, and the outer surface of the right wing weight portion 340 and the inner surface of the second wall portion 420 are secured. A gap dimension d12 is ensured between them. Therefore, the weight body can be displaced within the range of the gap dimensions d11 and d12 in the X-axis direction, but the displacement exceeding the range is limited. In this embodiment, d11 = d12 = 20 μm is set.

  19 is a side sectional view showing a cross section of the power generating element PGE shown in FIG. 17 along the cutting line 19-19, and FIG. 20 shows the power generating element PGE shown in FIG. 17 along the cutting line 20-20. It is a sectional side view which shows the cross section cut off. In any of the figures, it is clearly shown that the main power generation structure MGS and the pedestal 400 are formed of a three-layer structure.

  As shown in the figure, a gap dimension d13 is secured between the outer surface of the central weight portion 320 and the inner surface of the third wall portion 430, and the outer surfaces of the left wing weight portion 330 and the right wing weight portion 340 A gap dimension d14 is secured between the inner surface of the four wall portions 440. Therefore, the weight body can be displaced within the range of the gap dimensions d13 and d14 in the Y-axis direction, but the displacement exceeding the range is limited. In this embodiment, d13 = d14 = 15 μm is set.

  Here, the reason why the main power generation structure MGS is constituted by the three-layer structure of the main power generation first layer 100, the main power generation second layer 200, and the main power generation third layer 300 is to perform the power generation operation described in §2. Because. That is, the main power generation second layer 200 is a layer for configuring the plate-like bridge portion 210 having flexibility, and the main power generation first layer 100 is for detecting the bending generated in the plate-like bridge portion 210. The main power generation third layer 300 is a layer for functioning as a weight body that applies an external force to the plate-like bridge portion 210.

  On the other hand, the pedestal 400 can serve as a fixing member that supports and fixes the root end portion of the plate-like bridge portion 210 and a role as a displacement limiting wall that limits excessive displacement of the weight body. Therefore, it is not necessary to have a three-layer structure in terms of function. However, in the embodiment shown in FIGS. 18 to 20, the reason why the pedestal 400 is constituted by the three-layer structure similar to the main power generation structure MGS is exclusively for the convenience of the manufacturing process.

  That is, in the case of the embodiment shown in FIG. 18, the pedestal 400 is constituted by a laminated structure in which a pedestal first layer 401, a pedestal second layer 402, and a pedestal third layer 403 are laminated in order from the top. The layer 401 is connected to the main power generation first layer 100 in the vicinity of the root end portion of the plate-like bridge portion 210, and the pedestal second layer 402 is connected to the main power generation second layer 200 at the root end portion of the plate-like bridge portion 210. The pedestal third layer 403 is physically separated from the main power generation third layer 300, but is the lowest layer of the three-layer structure, and the position of the upper surface is the same. It has become.

  After all, in the case of the embodiment shown in FIG. 18, the pedestal first layer 401 and the main power generation first layer 100 can be composed of the same material layer, and the pedestal second layer 402 and the main power generation second layer 200 are combined. The pedestal third layer 403 and the main power generation third layer 300 can be composed of the same material layer.

  FIG. 21 is a side sectional view of a laminated material block 1000 used as a material constituting the main power generation structure MGS and the pedestal 400 of the power generation element PGE shown in FIG. The laminated material block 1000 is a laminated structure including three layers in which a material first layer 1001, a material second layer 1002, and a material third layer 1003 are laminated in order from the top. The broken line in the figure indicates a portion that should become the pedestal 400.

  In FIG. 21, the material first layer 1001 is a layer intended to constitute the main power generation first layer 100, and is formed by forming conductive layers to be electrodes on both the upper and lower surfaces of the piezoelectric material layer. Similarly, the material second layer 1002 is a layer intended to form the main power generation second layer 200, and can be formed of, for example, a silicon substrate suitable for forming the plate-like bridge portion 210. The material third layer 1003 is a layer intended to form the main power generation third layer 300 (weight body), and can be formed of a metal substrate such as SUS, for example.

  The main power generation structure MGS and the pedestal 400 shown in FIGS. 18 to 20 are configured simultaneously by performing necessary processing (for example, etching processing) on each layer of the laminated material block 1000 as described above. be able to. For this reason, the production process can be simplified to achieve mass production, and the production cost can be reduced.

  As described above, in the power generation element PGE shown in FIG. 17, since the main power generation structure MGS is accommodated in the pedestal 400 made of a ring-shaped structure, the horizontal component of acceleration exceeding a predetermined magnitude (component parallel to the XY plane) When this acts, it is possible to limit the displacement of the weight body. Here, an embodiment will be described in which the displacement of the weight body is limited even when a vertical component (a component parallel to the Z axis) of acceleration exceeding a predetermined magnitude is applied.

  FIG. 22 is a side sectional view showing such an embodiment. In the illustrated embodiment, the power generation element PGE shown in FIG. 17 is accommodated in the apparatus housing 600. In the present application, the power generation element PGE including the apparatus housing 600 is referred to as “power generation apparatus” for convenience. I will call it. That is, the “power generation device” referred to here is a power generation element PGE (an element having the main power generation structure MGS, the pedestal 400, and the power generation circuit 500) described so far, and an apparatus housing 600 that houses the power generation element PGE. It will be a device provided with.

  As illustrated, the pedestal 400 of the power generation element PGE is fixed to the apparatus housing 600, and when an external force that vibrates the apparatus housing 600 is applied, the weight body 300 (main power generation third layer) of the power generation element PGE is The plate-like bridge portion 210 vibrates in the apparatus housing 600 due to the bending. The power generation circuit 500 (not shown) performs a process of taking out the electric power generated by the vibration and outputting it to the outside.

  More specifically, the apparatus housing 600 is disposed so as to surround the periphery of the power generation element PGE, a base substrate 610 for supporting and fixing the power generation element PGE from below, an upper lid substrate 620 covering the upper side of the power generation element PGE, and the power generation element PGE. And a side wall plate 630 that connects the base substrate 610 and the upper lid substrate 620. The bottom surface of the pedestal 400 (the respective wall portions 410 to 440) of the power generation element PGE is positioned below the bottom surface of the weight body (main power generation third layer 300: 320, 330, 340) of the power generation element PGE. The bottom surface of 400 (the wall portions 410 to 440) is fixed to the top surface of the base substrate 610.

  As a result, a lower gap portion having a gap dimension d15 is formed between the upper surface of the base substrate 610 and the bottom surface of the weight body (main power generation third layer 300: 320, 330, 340). The upper lid substrate 620 is positioned above the upper surface of the main power generation first layer 100 of the power generation element PGE, and has an air gap dimension d16 between the lower surface of the upper lid substrate 620 and the upper surface of the main power generation first layer 100. A void is formed. In this embodiment, d15 = d16 = 10 μm is set.

  Therefore, when a vertical component of acceleration exceeding a predetermined magnitude acts on the power generation element PGE, a part of the main power generation structure PGE contacts the upper surface of the base substrate 610 or the lower surface of the upper lid substrate 620. Further displacement is limited. Thus, according to the power generation device shown in FIG. 22, the displacement of the weight body can be reduced even when excessive acceleration directed in any of the X axis, Y axis, and Z axis acts in the XYZ three-dimensional coordinate system. It becomes possible to restrict | limit and the damage of the plate-shaped bridge part 210 can be prevented.

  FIG. 23 is a side cross-sectional view of a power generation apparatus according to a modification in which the roles of the weight body and the base are reversed in the power generation apparatus shown in FIG. The power generation device shown in FIG. 23 is also a device including a power generation element PGE ′ and a device casing 600 that accommodates the power generation element PGE ′. The portion of the device casing 600 is completely the same as the device shown in FIG. The same. However, the power generating element PGE ′ shown in FIG. 23 is slightly different in structure from the power generating element PGE shown in FIG.

  In the case of the power generation device shown in FIG. 23, the main power generation third layer 300 ′ (320 ′, 330 ′, 340 ′) of the power generation element PGE ′ is fixed to the device housing 600, and the base 400 ′ (410 ′, 420 ′). , 430 ′, 440 ′) are suspended. Therefore, when an external force that vibrates the apparatus housing 600 is applied, the base 400 ′ of the power generating element PGE vibrates in the apparatus housing 600 due to the bending of the plate-like bridge portion 210. The power generation circuit 500 (not shown) performs a process of taking out the electric power generated by the vibration and outputting it to the outside.

  More specifically, the apparatus housing 600 surrounds the periphery of the power generation element PGE ′, a base substrate 610 for supporting and fixing the power generation element PGE ′ from below, an upper lid substrate 620 covering the upper side of the power generation element PGE ′. And a side wall plate 630 that connects the base substrate 610 and the upper lid substrate 620. The bottom surface of the base 400 '(410', 420 ', 430', 440 ') of the power generation element PGE' is the main power generation third layer 300 '(320', 330 ', 340') of the power generation element PGE '. Located above the bottom surface, the bottom surface of the main power generation third layer 300 ′ (320 ′, 330 ′, 340 ′) is fixed to the top surface of the base substrate 610.

  As a result, a lower gap having a gap dimension d17 is formed between the top surface of the base substrate 610 and the bottom surface of the base 400 ′ (410 ′, 420 ′, 430 ′, 440 ′). The upper lid substrate 620 is located above the upper surface of the main power generation first layer 100 of the power generation element PGE ′, and has a gap dimension d18 between the lower surface of the upper lid substrate 620 and the upper surface of the main power generation first layer 100. An upper gap is formed. In this embodiment, d17 = d18 = 10 μm is set.

  Therefore, when a vertical component of acceleration exceeding a predetermined magnitude acts on the power generation element PGE ′, a part of the main power generation structure PGE ′ is placed on the upper surface of the base substrate 610 or the lower surface of the upper lid substrate 620. In contact, further displacement is limited. Thus, in the case of the power generation apparatus shown in FIG. 23 as well, in the XYZ three-dimensional coordinate system, the displacement of the weight body is limited even if excessive acceleration directed in any direction of the X axis, Y axis, or Z axis acts. It is possible to prevent the plate-like bridge portion 210 from being damaged. As mentioned above, although the specific dimension value was illustrated about the space | gap dimension d11-d18, of course, the optimum value of these space | gap dimensions d11-d18 depends on the dimension value d1-d10 of each part shown in FIG. 6 and FIG. It should be determined.

  22 and the power generation device shown in FIG. 23, the main generation third layer 300 (320, 330, 340) is suspended in the device housing 600 in the former case. In this case, the pedestal 400 ′ (410 ′, 420 ′, 430 ′, 430 ′, 430 ′, 430 ′, 440 ′) functions as a weight body suspended in the apparatus housing 600, and vibration energy of the weight body is converted into electric energy. 23, in principle, the member 300 ′ should be referred to as a pedestal and the member 400 ′ should be referred to as a weight body. However, for convenience in comparison with the power generator illustrated in FIG. The member 300 ′ is called a weight body, and the member 400 ′ is called a pedestal.

  In general terms, the pedestal 400, 400 'that surrounds the outer side of the third main power generation layer 300, 300' is easier to form a structure having a larger mass. For example, in the example shown in FIG. 17, increasing the thickness of the first wall portion 410, the second wall portion 420, the third wall portion 430, and the fourth wall portion 440 increases the mass of the base 400. Easy. If a pedestal having a large mass is used as the weight body, a larger amount of power generation can be ensured. Therefore, as a general theory, the structure shown in FIG. 23 is more preferable than the structure shown in FIG. 22 in securing the amount of power generation. Of course, even when the structure shown in FIG. 23 is adopted, the displacement of the pedestal 400 ′ in the direction of each coordinate axis is limited, so that the effect of preventing the plate-like bridge portion 210 from being damaged can be obtained.

<<< §4. Modification of the present invention >>
Subsequently, some modifications of the power generating element PGE according to the basic embodiment described so far will be described.

<4-1. First Modification A: Modification of Planar Shape of Three-Layer Structure>
As shown in FIG. 1, the main power generation structure MGS constituting the power generation element PGE according to the basic embodiment described in §1 includes a main power generation first layer 100, a main power generation second layer 200, and a main power generation third layer. It is constituted by a three-layer structure in which 300 are laminated. The planar shapes of these three layers are shown in FIGS.

  Here, as can be seen by comparing FIG. 2 and FIG. 3, the planar shape of the main power generation first layer 100 and the planar shape of the main power generation second layer 200 are exactly the same, and the XY plane projection images of both overlap. It will be. This is because a manufacturing process is adopted in which the main power generation first layer 100 made of a piezoelectric element is formed in the entire area of the upper surface of the main power generation second layer 200 made of a silicon substrate.

  However, the role of the main power generation first layer 100 (piezoelectric element) is to cause the main power generation second layer 200 to bend and generate electric power based on this bend. It is sufficient that the layer 100 (piezoelectric element) is formed on the upper surface of the plate-like bridge portion 210 where the bending occurs. The main power generation first layer 100 shown in FIG. 2 is composed of four parts, ie, a bridge part piezoelectric layer 110, a central piezoelectric layer 120, a left wing piezoelectric layer 130, and a right wing piezoelectric layer 140. It is only necessary to provide the piezoelectric layer 110. More specifically, the piezoelectric layer 110 may be formed only in the region where the upper layer electrodes E1 to E4 are formed in the bridge portion piezoelectric layer 110.

  In short, the planar shape of the main power generation first layer 100 and the planar shape of the main power generation second layer 200 are not necessarily the same, and the main power generation first layer 100 is a plate-like bridge of the main power generation second layer 200. It is only necessary to have a piezoelectric element formed so as to cover at least a part of the upper surface of the portion 210.

  On the other hand, as can be seen by comparing FIG. 3 and FIG. 4, the planar shape of the main power generation second layer 200 and the planar shape of the main power generation third layer 300 are the same except for the plate-like bridge portion 210. ing. That is, the planar shapes of the center plate-like portion 220, the left wing plate-like portion 230, and the right wing plate-like portion 240 constituting each part of the main power generation second layer 200 shown in FIG. 3 are shown in FIG. The planar shape of the central weight part 320, the left wing weight part 330, and the right wing weight part 340 constituting each part of the main power generation third layer 300 is the same. The difference between the two in the planar shape is that the portion corresponding to the plate-like bridge portion 210 of the main power generation second layer 200 shown in FIG. 3 is the hollow portion in the main power generation third layer 300 shown in FIG. It is only the point which becomes 310.

  Thus, if the planar shape of the main power generation second layer 200 and the planar shape of the main power generation third layer 300 are made substantially the same, the outer shape of the three-layer planar shape becomes substantially the same, and the main power generation structure MGS The overall shape can be simplified. However, the planar shape of the main power generation second layer 200 and the planar shape of the main power generation third layer 300 are not necessarily the same.

  FIG. 24 is a top view showing the main power generation structure MGSa according to the first modification A of the main power generation structure MGS shown in FIG. 1. This main power generation structure MGSa is constituted by a three-layer structure of a main power generation first layer 100a, a main power generation second layer 200a, and a main power generation third layer 300a, similarly to the main power generation structure MGS shown in FIG. However, the planar shape of each layer is different. In the first modification A, the planar shape of the main power generation first layer 100a and the planar shape of the main power generation second layer 200a are the same, but they are greatly different from the planar shape of the main power generation third layer 300a. ing.

  Each part of the main power generation first layer 100a and each part of the main power generation second layer 200a have the same planar shape. Since FIG. 24 is a top view, the main power generation second layer 200a is hidden under the main power generation first layer 100a and does not appear in the drawing, but is indicated below the main power generation first layer 100a by the reference numerals in parentheses. Each component of the main power generation second layer 200a arranged in an overlapping manner is shown. As is apparent from the figure, the outer peripheral portion of the main power generation third layer 300a protrudes greatly outward from the outer peripheral portions of the main power generation first layer 100a and the main power generation second layer 200a.

  Specifically, the central weight portion 320a has a structure that protrudes greatly outside the central piezoelectric layer 120a and the central plate-shaped portion 220a. Further, the left wing weight portion 330a has a structure that protrudes larger than the left wing piezoelectric layer 130a and the left wing plate-like portion 230a, and the right wing weight portion 340a is more than the right wing piezoelectric layer 140a and the right wing plate-like portion 240a. It has a structure that projects outward.

  Since the main power generation structure MGSa having such a structure also has a plane-symmetric structure with respect to the YZ plane, the center of gravity Ga of the structure (weight body) constituting the main power generation third layer 300a is a plate-like bridge. It is located on the YZ plane below the portion 210a. Therefore, there is no change in the point that the weight body vibrates stably in each coordinate axis direction.

  Thus, the outer peripheral portion of the main power generation third layer 300a (the central weight portion 320a, the left wing weight portion 330a, the right wing weight portion 340a) functioning as a weight body is connected to the main power generation first layer 100a and the main power generation first. By adopting a structure that projects outward from the outer periphery of the two layers 200a, the function of protecting the main power generation first layer 100a and the main power generation second layer 200a can be improved when excessive vibration is applied. .

  That is, in the case of the main power generation structure MGS shown in FIG. 17, the plate-shaped bridge portion 210 that is most likely to be damaged is surrounded by the “U” -shaped structure, and thus an external force that causes excessive displacement is generated. Even if it adds, the plate-shaped bridge part 210 itself does not contact the base 400. However, as apparent from FIG. 18, the positions of the outer peripheral surfaces of the main power generation first layer 100, the main power generation second layer 200, and the main power generation third layer 300 are aligned, and thus an external force that causes excessive displacement. Is added, the outer peripheral portion of each layer comes into contact with the inner surface of the base 400. Since the main power generation first layer 100 and the main power generation second layer 200 are smaller in thickness than the main power generation third layer 300, the outer peripheral portion may be damaged when contacting the inner surface of the pedestal 400.

  On the other hand, in the case of the main power generation structure MGSa shown in FIG. 24, since the structure in which the outer peripheral portion of the main power generation third layer 300a having a large thickness is projected outward is adopted, an external force that causes excessive displacement is adopted. Is applied, the outer peripheral portion of the main power generation third layer 300a contacts the inner surface of the pedestal 400, and further displacement is limited. Therefore, it can prevent that the outer peripheral surface of the main power generation 1st layer 100a and the main power generation 2nd layer 200a with small thickness contacts the inner surface of the base 400, and can prevent that an outer peripheral part damages.

  In the main power generation structure MGSa shown in FIG. 24, the main power generation third layer 300a protrudes in all directions in the upper, lower, left and right directions in the figure. There is no need to let them. That is, with respect to the main power generation third layer 300a functioning as a weight body, a part of the outer peripheral portion of the main power generation third layer 300a is in contact with the inner surface of the pedestal 400, thereby limiting the vertical displacement and the horizontal displacement of the figure It is sufficient if the structure is such that

  Specifically, the X-axis positive end of the main power generation third layer 300a protrudes in the X-axis positive direction from the X-axis positive end of the weight support portions (220a, 230a, 240a). The X-axis negative direction end of the main power generation third layer 300a protrudes in the X-axis negative direction from the X-axis negative direction ends of the weight support portions (220a, 230a, 240a). The Y-axis positive direction end of the three layers 300a protrudes in the Y-axis positive direction from the Y-axis positive direction ends of the weight support portions (220a, 230a, 240a), and the main power generation third layer 300a The end in the Y-axis negative direction may protrude in the negative Y-axis direction from the end in the negative Y-axis direction of the weight support portions (220a, 230a, 240a).

<4-2. Second Modification B: Weight Body Separation Structure>
In the basic embodiment described so far, as shown in FIG. 4, the main power generation third layer 300 functioning as a weight body is divided into three parts including a central weight part 320, a left wing weight part 330, and a right wing weight part 340. It was comprised by one part (the 1st modification A shown in FIG. 24 is also the same). However, in the present invention, as the weight body, the left wing weight portion 330 located on the left side and the right wing weight portion 340 located on the right side with respect to the longitudinal direction axis (Y axis) of the plate-like bridge portion 210, If the main power generation structure MGS is used, the necessary functions and effects can be obtained. In other words, the central weight portion 320 that connects the left wing weight portion 330 and the right wing weight portion 340 is not essential in carrying out the present invention.

  FIG. 25 is a top view showing a second modification B of the main power generation structure MGS shown in FIG. The main power generation structure MGSb shown in the figure is the same as the main power generation structure MGS shown in FIG. 1 and the main power generation structure MGSa shown in FIG. 24. The main power generation first layer 100b, the main power generation second layer 200b, and the main power generation third The layer 300b includes a three-layer structure. Again, the reference numerals in parentheses indicate the components of the main power generation second layer 200b disposed below. The main power generation first layer 100b (110b, 120b, 130b, 140b) shown in FIG. 25 is the same component as the main power generation first layer 100a (110a, 120a, 130a, 140a) shown in FIG. The main power generation second layer 200b (210b, 220b, 230b, 240b) shown in FIG. 25 is the same component as the main power generation second layer 200a (210a, 220a, 230a, 240a) shown in FIG.

  The main power generation structure MGSa shown in FIG. 24 is different from the main power generation structure MGSb shown in FIG. 25 only in the structure part of the main power generation third layer that functions as a weight body. That is, in the case of the main power generation structure MGSa shown in FIG. 24, the main power generation third layer 300a has a “U” shape composed of three parts: a central weight part 320a, a left wing weight part 330a, and a right wing weight part 340a. In the case of the main power generation structure MGSb shown in FIG. 25, the main power generation third layer 300b is a structure composed of two parts, a left wing weight part 330b and a right wing weight part 340b. A central weight portion that connects the two is not provided.

  The left wing weight portion 330b is joined to the lower surface of the left wing plate-like portion 230b (weight body support portion), and the right wing weight portion 340b is joined to the lower surface of the right wing plate-like portion 240b (weight body support portion). The displacement generated in the weight body is transmitted to the tip of the plate-like bridge portion 210b without any trouble.

  In the main power generation structure MGSb having such a structure, the weight body is separated into two parts, a left wing weight part 330b and a right wing weight part 340b, but has a plane-symmetric structure with respect to the YZ plane. Therefore, the gravity center Gb of the weight body is located on the YZ plane below the plate-like bridge portion 210b. Therefore, there is no change in the point that the weight body vibrates stably in each coordinate axis direction.

  In addition, the main power generation structure MGSb shown in FIG. 25 is similar to the main power generation structure MGSa shown in FIG. 24 in that the third main power generation structure MGSb is compared with the outer periphery of the main power generation first layer 100b and the main power generation second layer 200b. Since the outer peripheral portion of the layer 300b projects outward, it is possible to prevent the outer peripheral surfaces of the main power generation first layer 100b and the main power generation second layer 200b having a small thickness from contacting the inner surface of the base 400. Moreover, the effect which prevents that an outer peripheral part damages is also acquired.

  That is, in FIG. 25, the end in the X-axis positive direction of the right wing weight part 340b protrudes in the X-axis positive direction from the end in the X-axis positive direction of the right wing plate-like part 240b (weight support part). The end of the left wing weight portion 330b in the X axis negative direction protrudes in the X axis negative direction from the end of the left wing plate-like portion 230b (weight support portion) in the X axis negative direction. The ends in the Y-axis positive direction of the weight portion 330b and the right wing weight portion 340b are more positive in the Y-axis direction than the ends in the Y-axis positive direction of the left wing plate-like portion 230b and the right wing plate-like portion 240b (weight body support portion). The ends of the left wing weight portion 330b and the right wing weight portion 340b in the Y-axis negative direction protrude in the direction of the left wing plate portion 230b and the right wing plate-like portion 240b (weight body support portion). Protrudes in the negative direction of the Y-axis from the end.

  Therefore, the outer peripheral portion of the main power generation third layer 300b (weight body) is always the pedestal even if an external force that causes excessive displacement is applied to the weight body in the vertical direction or the horizontal direction in the figure. It contacts the inner surface of 400 and further displacement is limited. For this reason, it can prevent that the outer peripheral surface of the main power generation 1st layer 100b and the main power generation 2nd layer 200b with small thickness contacts the inner surface of the base 400, and can prevent that an outer peripheral part damages.

<4-3. Third Modification C: Connection Angle of Plate-shaped Bridge>
FIG. 26 is a top view showing a connection angle between both ends of the plate-like bridge portion 210 in the main power generation second layer 200 of the main power generation structure MGS shown in FIG. As shown in the figure, the main power generation second layer 200 is composed of four parts: a plate-like bridge portion 210, a central plate-like portion 220, a left wing plate-like portion 230, and a right wing plate-like portion 240.

  Here, the plate-like bridge portion 210 is a central portion that generates a bend that is directly related to the power generation operation, and has a flexibility that extends along the first longitudinal axis L1 (the Y axis in the above description). It has a beam-like structure. On the other hand, the central plate-like portion 220 is a structure that extends along a second longitudinal axis L2 (X ′ axis in the above description) orthogonal to the first longitudinal axis L1. Are arranged at positions which are symmetrical with respect to the longitudinal axis L1. And the front-end | tip part of the plate-shaped bridge part 210 is connected to the center side part of the center plate-shaped part 220 in the front-end | tip point T, and both make a T-shaped structure.

  Further, a left wing plate-like portion 230 is connected to the left side of the central plate-like portion 220, and a right wing plate-like portion 240 is connected to the right side. The main power generation second layer 200 has a planar shape “E” as a whole. A flat plate-like structure having a letter shape is formed. A boundary line H ′ in the figure corresponds to a boundary line for partitioning the regions of these parts from each other.

  In the main power generation second layer 200, when attention is paid to the connection state with respect to the central plate-like portion 220 at the tip end portion (near the tip point T) of the plate-like bridge portion 210, the connection angles θ1 and θ2 shown in the figure are , Both are 90 °. Here, the connection angle θ1 is an angle formed between the left side of the plate-like bridge portion 210 and the boundary line H ′, and the connection angle θ2 is an angle formed between the right side of the plate-like bridge portion 210 and the boundary line H ′. It is. As described above, the connection angles θ1 and θ2 are 90 ° because the first longitudinal axis L1 and the second longitudinal axis L2 are orthogonal to each other and the rectangular plate-like bridge portion 210 is the first. This is because the longitudinal central axis L1 is arranged as the central axis, and the rectangular central plate-like portion 220 is arranged with the second longitudinal axis L2 as the central axis.

  Similarly, when attention is paid to the connection state with respect to the base 400 at the root end portion (near the origin O) of the plate-like bridge portion 210, the connection angles θ3 and θ4 shown in the figure are both 90 °. Here, the connection angle θ3 is an angle formed between the left side of the plate-like bridge portion 210 and the inner side surface of the pedestal 400, and the connection angle θ4 is the angle between the right side of the plate-like bridge portion 210 and the inner side surface of the pedestal 400. It is an angle to make. As described above, the connection angles θ3 and θ4 are 90 ° because the first longitudinal axis L1 is orthogonal to the inner surface of the pedestal 400 and the rectangular plate-like bridge portion 210 is in the first longitudinal direction. This is because the axis L1 is arranged as the central axis.

  On the other hand, FIG. 27 is a top view showing a main power generation second layer 200c according to the third modification C of the main power generation structure MGS shown in FIG. Also in the case of the third modification C, the main power generation second layer 200c is composed of four parts: a plate-like bridge portion 210c, a central plate-like portion 220c, a left-wing plate-like portion 230c, and a right-wing plate-like portion 240c. However, the planar shape of these individual parts is not a rectangle but an irregular figure. Further, the plate-like bridge portion 210 c is a member extending in the direction along the longitudinal axis L 1 ′, but the longitudinal axis L 1 ′ is not orthogonal to the inner side surface of the pedestal 400. Therefore, the connection angles θ1 and θ2 for the distal end portion of the plate-like bridge portion 210c and the connection angles θ3 and θ4 for the root end portion are not 90 °.

  Thus, even when the power generation element according to the present invention is formed using the main power generation second layer 200c having the irregular shape according to the third modification C shown in FIG. Is possible. That is, if a weight body having a left wing weight portion 330c joined to the lower surface of the left wing plate-like portion 230c and a right wing weight portion 340c joined to the lower surface of the right wing plate-like portion 240c is provided, the weight Due to the vibration of the weight, the plate-like bridge portion 210c is bent, so that electric power can be generated by the piezoelectric element provided on the upper surface thereof.

  Therefore, in carrying out the present invention, the plate-like bridge portion and the central plate-like portion do not necessarily need to be orthogonal to each other, and it is not always necessary to form a T-shaped structure by both. For example, in the case of Modification C shown in FIG. 27, the plate-like bridge portion 210c and the central plate-like portion 220c have a shape close to a Y-shape. Further, the plate-like bridge portions do not necessarily have to be connected in a form orthogonal to the inner surface of the pedestal 400. Furthermore, the planar shape of each part constituting each layer of the main power generation structure does not necessarily have to be a rectangle, and may be an arbitrary shape.

  However, practically, as in the example shown in FIG. 26, each part of the main power generation second layer 200 is configured by a member whose plane is rectangular, and the plate-like bridge part 210 is orthogonal to the inner surface of the pedestal 400. The first longitudinal axis L1 is disposed as the central axis, and the central plate-like portion 220 is disposed such that the second longitudinal axis L2 orthogonal to the first longitudinal axis L1 is the central axis. The plate-like bridge portion 210 and the central plate-like portion 220 are preferably perpendicular to each other to form a T shape. When such a configuration is adopted, the connection angles θ1 to θ4 are all 90 °, and stress can be concentrated on the tip and root ends of the plate-like bridge portion 210 (see FIGS. 13 to 15). , Charges can be efficiently generated in the four upper layer electrodes E1 to E4 arranged at the positions shown in FIG.

<4-4. Fourth Modification D: Independent Main Power Generation Components>
Since the power generating element PGE shown in FIG. 18 includes both the main power generation structure MGS and the pedestal 400 in a three-layer structure, a single laminated material block 1000 as shown in FIG. 21 is prepared. As described above, it can be manufactured by processing such as etching, and is suitable for mass production.

  Here, in the three-layer structure constituting the main power generation structure MGS, the main power generation first layer 100 needs to use a piezoelectric element in order to perform a power generation operation. Further, a silicon substrate is suitable for the main power generation second layer 200, and a metal substrate is suitable for the main power generation third layer 300. This is because, as described above, a silicon substrate is optimal as the support layer of the piezoelectric element, and it is optimal to configure the weight body with a metal substrate in order to make the resonance frequency in the range of 10 Hz to 50 Hz. It is.

  In particular, considering mass productivity, in the stage of preparing the laminated material block 1000 shown in FIG. 21, the material second layer 1002 is formed of a silicon substrate, and a metal layer to be the lower layer electrode E0 is formed on the upper surface thereof. A piezoelectric material layer is formed on the upper surface, and further, a metal layer to be the upper layer electrodes E1 to E4 is formed on the upper surface, thereby forming a first material layer 1001, and this is a third material layer 1003 made of a metal substrate. It is preferable to be bonded to the upper surface.

  However, at present, the processing process for forming a piezoelectric element on a silicon substrate requires advanced equipment and is very expensive. In fact, with the current technology, the process of forming a piezoelectric element on a silicon substrate costs more than 10 times the material price of the silicon substrate. Therefore, even if the process for producing the power generating element PGE shown in FIG. 18 can be efficiently performed using the laminated material block 1000 shown in FIG. 21, the procurement cost of the laminated material block 1000 is relatively high. I have to be.

  Actually, the piezoelectric element directly related to the power generation function of the power generation element PGE is only the portion formed on the upper surface of the plate-like bridge portion 210, and it is not necessary to form the piezoelectric element in other areas. In particular, the piezoelectric element formed on the pedestal 400 is useless, and there is no need to use a silicon substrate for the pedestal 400 in the first place. Therefore, here, a modified example in which the planar size of the silicon substrate and the piezoelectric element formed on the upper surface of the silicon substrate can be significantly reduced to reduce the manufacturing cost will be described.

  FIG. 28 is a diagram showing a main power generation component 700d used in the fourth modification D of the main power generation structure MGS shown in FIG. 1, FIG. 28 (a) is a top view thereof, and FIG. It is the front sectional view cut along cutting line bb. In FIG. 28 (a), the reference numerals in parentheses indicate the components of each layer. The fourth modification D described here is in principle the same as the basic embodiment described so far, but the specific component configuration is slightly different. The main power generation component 700d shown in FIG. 28 serves as a component obtained by removing the weight portion from the main power generation structure MGS in the basic embodiment described so far.

  As shown in the top view of FIG. 28 (a), the main power generation component 700d extends along the first member 710d extending along the first longitudinal axis L1 and along the second longitudinal axis L2. The second member 720d and the third member 730d extending along the third longitudinal axis L3 are configured. Here, the first longitudinal axis L1, the second longitudinal axis L2, and the third longitudinal axis L3 are all included on the same common plane, and the first longitudinal axis L1 and the second longitudinal axis L1. The longitudinal axis L2 is orthogonal, and the first longitudinal axis L1 and the third longitudinal axis L3 are orthogonal (the second longitudinal axis L2 and the third longitudinal axis L3 are parallel). .

  In the front cross-sectional view of FIG. 28 (b), only a cross-sectional portion obtained by cutting the first member 710d along the cutting line bb is shown. As illustrated, the first member 710d is formed, for example, by forming a lower layer electrode E0 made of metal on the upper surface of a plate-like bridge portion 712d made of silicon, forming a bridge portion piezoelectric layer 711d on the upper surface, It has a structure in which upper layer electrodes E1 to E4 (only E1 and E2 located on the cut surface appear in the drawing) are formed at predetermined locations. The layer structure and the thickness dimension of each layer are shown in FIG. This is the same as the embodiment shown. Therefore, in this embodiment, the thickness dimension d19 of the first member 710d (the dimension from the lower surface of the plate-like bridge portion 712d to the upper surface of the upper layer electrodes E1 to E4) is the sum of the thicknesses of the four layers, that is, 0. 01 + 2.00 + 0.01 + 200.00 = 202.02 μm.

  Although illustration is omitted, the second member 720d and the third member 730d also have the same layer structure. That is, the second member 720d has a structure in which, for example, a lower electrode E0 made of metal is formed on the upper surface of the central plate-shaped portion 722d made of silicon, and a central piezoelectric layer 721d is formed on the upper surface thereof, and the third member In 730d, for example, a lower layer electrode E0 made of metal is formed on the upper surface of a base connection portion 732d made of silicon, a connection portion piezoelectric layer 731d is formed on the upper surface, and a bonding pad B (shown in the figure) is further formed on the upper surface. In this example, it is provided with a structure formed at five locations.

  Here, the thickness of the third member 730d is the same dimension d19 as the thickness of the first member 710d (because the thickness of the bonding pad B is set to be the same as the thickness of the upper layer electrodes E1 to E4). On the other hand, in the illustrated embodiment, the upper layer electrodes E1 to E4 and the bonding pad B are not formed on the upper surface of the second member 720d. Therefore, the thickness of the second member 720d is slightly smaller than the dimension d19. Wiring (not shown) is provided between the five sets of bonding pads B and the electrodes E0 to E4. For each bonding pad B, wiring from the power generation circuit 500 is made.

  Also in the fourth modification D, the four upper layer electrodes E1 to E4 are located at both the left and right side positions near the upper end of the first member 710d and the left and right side positions near the lower end of the first member 710d. Each of them is formed and arranged in a region where stress is concentrated. 13 to 15, the upper end positions of the upper layer electrodes E1 and E2 shown in FIG. 28 slightly exceed the boundary line between the first member 710d and the second member 720d. It turns out that it may extend above the figure (region of the 2nd member 720d). Similarly, the lower end position of the upper layer electrodes E3 and E4 shown in FIG. 28 extends slightly below the figure (region of the third member 730d) beyond the boundary line between the first member 710d and the third member 730d. It turns out that it may be.

  On the other hand, FIG. 29 is a top view showing a weight body 300d used in the fourth modification example D. FIG. Similar to the weight body 300 (main power generation third layer) shown in FIG. 4, the weight body 300d is made of a material such as metal, glass, ceramics, etc., and has a central weight portion 320d, a left wing weight portion 330d, It is a “U” -shaped component having three parts, ie, a right wing weight part 340d, and has a hollow part 310d. Of course, the thickness of the weight body 300d is set to a dimension that provides a sufficient mass for causing the first member 710d shown in FIG. 28 to bend. In the illustrated embodiment, a rectangular fitting groove 325d is formed on the upper surface of the central weight portion 320d. As will be described later, the fitting groove 325d is for fitting and fixing the second member 720d of the main power generation component 700d shown in FIG. 28. The depth dimension of the fitting groove 325d is that of the second member 720d. It is set to be larger than the thickness dimension.

  FIG. 30 is a top view showing a pedestal 400d used in the fourth modification D. FIG. The pedestal 400d is a rectangular component having a first wall portion 410d, a second wall portion 420d, a third wall portion 430d, and a fourth wall portion 440d, similarly to the pedestal 400 shown in FIG. However, the pedestal 400 is constituted by a three-layer structure (having the same layer structure as the main power generation structure MGS) as shown in FIG. 18, whereas the pedestal 400d shown in FIG. It is not necessary to have a layer structure, and for example, a single layer structure made of a material such as metal may be used. This is because in the case of the fourth modification example D shown here, the pedestal 400d is manufactured by a completely separate process from the main power generation component 700d shown in FIG.

  In the illustrated embodiment, a rectangular fitting groove 445d is formed at the center of the upper surface of the fourth wall portion 440d. As will be described later, the fitting groove 445d is for fitting and fixing the third member 730d of the main power generation component 700d shown in FIG. 28. The depth dimension of the fitting groove 445d is that of the third member 730d. It is set to be larger than the thickness dimension.

  FIG. 31 is a top view showing the overall configuration of the power generating element PGEd according to the fourth modification D (however, only the power generating element structure excluding the power generating circuit 500 is shown, and the power generating circuit 500 Not shown). This power generation element PGEd is configured by attaching a main power generation component 700d shown in FIG. 28 and a weight body 300d shown in FIG. 29 to a pedestal 400d shown in FIG.

  Specifically, the second member 720d of the main power generation component 700d shown in FIG. 28 is inserted into the fitting groove 325d provided in the central weight part 320d of the “U” -shaped weight body 300d shown in FIG. The lower surface of the second member 720d is bonded to the bottom surface of the fitting groove 325d. Similarly, the third member 730d of the main power generation component 700d is fitted into the fitting groove 445d provided in the fourth wall portion 440d of the base 400d shown in FIG. 30, and the lower surface of the third member 730d is fitted to the fitting groove 445d. Adhere to the bottom. Then, the power generating element PGEd shown in FIG. 31 is completed (in practice, it is necessary to perform wiring between the power generating circuit 500 and the bonding pad B which are not shown).

  After all, the power generation element PGEd shown in FIG. 31 also adopts a configuration in which the main power generation structure MGSd is accommodated in the rectangular pedestal 400d, and the point that the main power generation structure MGSd consists of a three-layer structure is shown in FIG. This is the same as the power generation element PGE according to the basic embodiment shown. However, as indicated by the reference numerals in parentheses in FIG. 28, the main power generation second layer constituting the main power generation structure MGSd further includes a base connection portion 732d connected to the root end portion of the plate-like bridge portion 712d. Yes. This pedestal connecting portion 732d has a third longitudinal axis L3 (an axis parallel to the X axis in the basic embodiment) intersecting the first longitudinal axis L1 (Y axis in the basic embodiment) as an arrangement axis. , A member that is arranged on the arrangement axis and extends along the arrangement axis.

  As shown in FIG. 29, a fitting groove 325d for fitting the central plate-like portion 722d (second member 720d) and bonding the lower surface is formed on the upper surface of the predetermined portion of the weight body 300d. The central plate portion 722d is fixed in a state of being fitted in the fitting groove 325d. Similarly, as shown in FIG. 30, a fitting groove 445d for fitting the base connection portion 732d (third member 730d) and bonding the lower surface is formed on the upper surface of a predetermined portion of the base 400d. The base connecting portion 732d is fixed in a state of being fitted in the fitting groove 445d.

  As shown in FIG. 31, in the embodiment shown here, the planar shape of the fitting groove 325d is designed to be slightly larger than the planar shape of the second member 720d, and the second member 720d is fitted into the fitting groove. Fit in 325d with a margin. On the other hand, the planar shape of the fitting groove 445d is designed so as to coincide with the planar shape of the third member 730d, and the third member 730d is fitted into the fitting groove 445d. Of course, the relationship between the planar shapes of the fitting grooves 325d and 445d and the members 720d and 730d fitted therewith is not necessarily the same as in this embodiment. In either case, the groove may be designed to fit in the groove with sufficient margin or may be designed to fit snugly.

  On the other hand, the relationship between the depth of the fitting grooves 325d and 445d and the thickness of the members 720d and 730d fitted therein is such that the former dimension is larger than the latter dimension, that is, the fitting. It is preferable that the groove is designed to be deeper than the thickness of the member. This is a consideration for protecting the main power generation component 700d from damage. The main power generation component 700d is, for example, a component including a silicon substrate, a piezoelectric element layer, and an electrode, and thus is easily damaged compared to the weight body 300d and the pedestal 400d. Therefore, if the members 720d and 730d are completely embedded in the fitting grooves 325d and 445d, the possibility that the main power generation component 700d is in contact with some other member and is damaged can be reduced.

  In the case of the embodiment shown in FIG. 31, the depth dimension of the fitting groove 325d is set to be larger than the thickness dimension of the second member 720d, so that the upper surface of the second member 720d is the central weight portion. The second member 720d is completely embedded in the weight body 300d and positioned below the upper surface of 320d (in the rear direction in the figure), and is protected from contact with an external member. Similarly, since the depth dimension of the fitting groove 445d is set to be larger than the thickness dimension of the third member 730d, the upper surface (the upper surface including the bonding pad B) of the third member 730d is Located below the upper surface of the four wall portions 440d (in the back direction in the figure), the third member 730d is completely embedded in the pedestal 400d and is protected from contact with external members. Yes. By adopting such a configuration, it is possible to prevent the main power generation component 700d from coming into contact with some other member and being damaged even when excessive acceleration is applied and the respective parts are greatly displaced.

  The manufacturing process of the power generating element PGEd according to the fourth modification D is different from the manufacturing process of the power generating element PGE according to the basic embodiment shown in FIGS. However, even when the layer connected to the plate-like bridge portion 712d is made of silicon, it is sufficient to form the silicon layer and the piezoelectric element on the upper surface only in the main power generation component 700d shown in FIG. Therefore, the planar size of the silicon substrate and the piezoelectric element formed on the upper surface thereof can be greatly reduced, and the manufacturing cost can be reduced.

  In the case of the fourth modification D, as shown in FIG. 28, the first member 710d (plate-like bridge portion 712d) disposed along the first longitudinal axis L1 and the second longitudinal axis Since the second member 720d (center plate-like portion 722d) disposed along L2 and the third member 730d (pedestal connection portion 732d) disposed along the third longitudinal axis L3 are orthogonal to each other, Connection angles θ1 to θ4 shown in FIG. 26 can be set to 90 °. Therefore, efficient stress can be generated at both ends of the plate-like bridge portion 712d, and the power generation efficiency can be increased.

<<< §5. Basic concept of the present invention >>
As described above, in §1 to §3, the basic embodiment of the present invention is described, and in §4, some modifications are described. Of course, the modified example of the present invention is not limited to the modified example described in §4, and various other modified examples can be implemented as long as the same operational effects can be obtained. is there.

  For example, in the basic embodiments and modifications described so far, the main power generation structure MGS is configured by a three-layer structure. However, in implementing the present invention, it is not necessary to use a three-layer structure. There is no. For example, the main power generation second layer 200 and the main power generation third layer 300 may be fused so that the plate-like bridge portion and the weight body are integrally formed of a silicon substrate or the like. Of course, the plate-like bridge portion, the weight body, and the pedestal can be integrally formed of the same material such as silicon.

  Further, in the examples so far, the main power generation third layer 300 constituting the weight body is disposed below the plate-like bridge portion, but the weight body continuous from the bottom to the top of the plate-like bridge portion is provided. It does not matter if it is provided.

  Here, the basic concept of the present invention will be summarized based on the basic embodiments and various modifications described so far. The power generation element according to the present invention is a power generation element that generates power by converting vibration energy into electrical energy, and extends along the first longitudinal axis Y as shown in FIG. A plate-like bridge portion 210, a pedestal 400 for supporting and fixing the root end portion of the plate-like bridge portion 210, a weight body 300 connected directly or indirectly to the tip portion of the plate-like bridge portion 210, a plate A piezoelectric element 100 fixed at a predetermined position where the surface of the bridge portion 210 is stretched and deformed, and a power generation circuit 500 that rectifies a current generated based on the electric charge generated in the piezoelectric element 100 and extracts electric power, The weight body 300 has a left wing weight portion 330 located on the left side with respect to the longitudinal axis Y of the plate-like bridge portion 210 and a right wing weight portion 340 located on the right side with respect to the longitudinal direction axis Y of the plate-like bridge portion 210. And have Good.

  However, in order to perform more efficient power generation, the weight body support portions 220, 230, and 240 are connected to the front end portion of the plate-like bridge portion 210, and the weight body 300 is connected to the lower surface thereof. It is preferable that the center of gravity G of the body 300 is located below the plate-like bridge portion 210.

  In particular, in the basic embodiment shown in FIG. 1, a central plate-like portion 220 extending along a second longitudinal axis X ′ orthogonal to the first longitudinal axis Y is provided as a weight support portion. The tip of the plate-like bridge portion 210 is connected to the vicinity of the center of the central plate-like portion 220 so that the plate-like bridge portion 210 and the central plate-like portion 220 form a T-shaped structure. The left wing weight portion 330 is connected to the lower surface on the left side of the central plate-shaped portion 220, and the right wing weight portion 340 is connected to the lower surface on the right side of the central plate-shaped portion 220.

  More specifically, in the case of the basic embodiment shown in FIG. 1, the weight support portion extends along the second longitudinal axis X ′ orthogonal to the first longitudinal axis Y, and the vicinity of the center is A central plate-like portion 220 connected to the tip of the plate-like bridge portion 210, a left wing plate-like portion 230 extending from the left side of the central plate-like portion 220 to the left side of the plate-like bridge portion 210, and the central plate-like portion 210 The right wing plate portion 240 extends from the right side to the right side of the plate-like bridge portion 210. The left wing weight portion 330 is connected to the lower surface of the left wing plate portion 230, and the right wing weight portion 340 is connected to the right wing. A structure connected to the lower surface of the plate-like portion 240 is adopted. Further, the weight body 300 is provided with a central weight portion 320 that connects the left wing weight portion 330 and the right wing weight portion 340, and the central weight portion 320 is connected to the lower surface of the central plate-like portion 220. I have to.

  By adopting such a configuration, it is possible to realize a structure in which the periphery of the plate-like bridge portion 210 is covered with the weight body 300 in a “U” shape, and the gravity center G of the weight body 300 is set to the plate-like bridge portion. It can be placed at a predetermined position below 210. Therefore, the plate-like bridge portion 210 can be flexed efficiently based on the displacement of the weight body 300. In addition, if some kind of displacement limiting wall is provided around the weight body 300, the displacement of the weight body 300 is limited even when an external force that causes excessive displacement acts on the weight body 300. The plate-like bridge portion 210 can be prevented from being damaged.

  Practically, it is preferable to use the pedestal 400 as a displacement limiting wall that limits the displacement of the weight body 300. For example, in the case of the embodiment shown in FIG. 17, a pedestal 400 forming an annular structure surrounding the main power generation structure MGS having the plate-like bridge portion 210 and the weight body 300 is used. By doing so, when an acceleration exceeding a predetermined magnitude is applied to the power generation element PGE, a part of the weight body 300 comes into contact with a part of the pedestal 400 formed of the annular structure, and the displacement is more than that. Can be limited.

  As shown in FIG. 26, when the plate-like bridge portion 210 and the central plate-like portion 220 are orthogonal to form a T-shaped structure, forces in the coordinate axis directions act on the weight body 300. In this case, as shown in FIGS. 13 to 15, stress concentration is observed on both the left and right sides of the distal end portion of the plate-like bridge portion 210 and the left and right sides of the root end portion.

  Therefore, as the piezoelectric elements, the left end piezoelectric element P1 (piezoelectric element formed in the region of the upper layer electrode E1) disposed on the left side in the vicinity of the front end of the plate-like bridge portion 210 and the front end of the plate-like bridge portion 210 are used. Right end piezoelectric element P2 disposed on the right side in the vicinity of the section (piezoelectric element formed in the region of the upper layer electrode E2) and left end piezoelectric section on the left side in the vicinity of the root end of the plate-like bridge portion 210 The element P3 (piezoelectric element formed in the region of the upper layer electrode E3) and the root end right side piezoelectric element P4 (formed in the region of the upper layer electrode E4) arranged on the right side in the vicinity of the root end portion of the plate-like bridge portion 210. If the piezoelectric element is provided, efficient power generation is possible.

  Further, as shown in FIG. 1, the specific structure of the piezoelectric element was formed in a layered manner on the surface of the plate-like bridge portion 210 and on the surface of the lower layer electrode E0. A laminated structure including the piezoelectric material layer 105 and an upper electrode group including a plurality of upper layer electrodes E1 to E4 locally formed on the surface of the piezoelectric material layer 105 may be employed. Here, the piezoelectric material layer 105 may be made of a material having a property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction.

  In the embodiment shown in FIG. 1, the piezoelectric element (main power generation first layer 100) is formed on the upper surface of the plate-like bridge portion 210 (main power generation second layer 200), but the piezoelectric element is not necessarily a plate. It is not necessary to form on the upper surface of the bridge-like bridge part 210, and it is also possible to form it on the side surface or the lower surface. Of course, it may be formed on both the upper surface and the side surface, or may be formed on all of the upper surface, the side surface, and the lower surface. Since the bending of the plate-like bridge portion 210 generates stress not only on the upper surface but also on the side surface and the lower surface, it is possible to generate electric power also by the piezoelectric elements formed on the side surface and the lower surface.

  In short, the piezoelectric element may be formed on the surface of the plate-like bridge portion 210 regardless of the upper surface, the side surface, and the lower surface. For example, the lower layer electrode E0 is formed so as to be continuous from the upper surface to the side surface of the plate-like bridge portion 210, the piezoelectric material layer 105 is formed over the entire surface of the lower layer electrode E0, and a predetermined portion (on the surface of the piezoelectric material layer 105 ( If a plurality of upper layer electrodes are locally formed on a predetermined portion including not only the upper side of the plate-like bridge portion 210 but also the side thereof, the piezoelectric element is provided not only on the upper surface but also on the side surface of the plate-like bridge portion 210. Will be formed. In this case, power generation is possible not only with the piezoelectric element formed on the upper surface but also with the piezoelectric element formed on the side surface.

  However, in order to form a piezoelectric element not only on the upper surface of the plate-like bridge portion 210 but also on the side surface and the lower surface, a complicated process is required, so that the manufacturing cost must be increased. Therefore, in practice, as shown in the basic embodiments and modifications thereof described so far, it is preferable to employ a structure in which a piezoelectric element is provided on the upper surface of the plate-like bridge portion 210 to reduce the cost. In particular, when a laminated material block 1000 as shown in FIG. 21 is prepared and a mass production process in which a predetermined processing is applied thereto, the piezoelectric element must be formed on the upper surface of the plate-like bridge portion 210.

  When the power generation element PGE is accommodated in the apparatus housing 600 to configure the power generation apparatus as in the example illustrated in FIG. 22, the base 400 of the power generation element PGE is fixed to the apparatus housing 600 and the apparatus housing When an external force that vibrates the body 600 is applied, the weight body 300 of the power generation element PGE is caused to vibrate within the apparatus housing 600 due to the bending of the plate-like bridge portion 210, and is extracted from the power generation circuit 500 according to the vibration. A configuration for outputting the generated power may be employed.

  Or it is also possible to take the structure which reverses the role of a weight body and a base like the example shown in FIG. In this case, a power generation element PGE ′ is prepared in which the bottom surface of the weight body 300 ′ is located below the bottom surface of the pedestal 400 ′, and the weight body 300 ′ of the power generation element PGE ′ is provided in the apparatus housing 600. When an external force that fixes and vibrates the device casing 600 is applied, the pedestal 400 ′ of the power generation element PGE ′ vibrates in the device casing 600 due to the bending of the plate-like bridge portion 210, and according to the vibration. Thus, a configuration for outputting electric power extracted from the power generation circuit 500 may be employed.

  Of course, the power generation element PGE can also be configured by a method of assembling several individual parts as in the embodiment shown in FIGS. In the case of the main power generation component 700d shown in FIG. 28, the base connection portion 732d extending along the longitudinal axis L3 orthogonal to the longitudinal axis L1 is formed at the root end portion of the plate-like bridge portion 712d extending along the longitudinal axis L1. Are connected, and the base connection part 732d is fixed to the base 400d so that assembly can be performed.

100: Main power generation first layer 105: Piezoelectric material layer 110: Bridge portion piezoelectric layer 120: Central piezoelectric layer 130: Left wing piezoelectric layer 140: Right wing piezoelectric layer 200: Main power generation second layers 210, 210a, 210b, 210c: Plate shape Bridge parts 220, 220a, 220b, 220c: central plate-like part (weight body support part)
230, 230a, 230b, 230c: Left wing plate-like part (weight body support part)
240, 240a, 240b, 240c: right wing plate-like part (weight body support part)
300, 300d: Main power generation third layer (weight body)
310, 310d: cavity portion 320, 320a, 320d: central weight portion (weight body)
325d: fitting grooves 330, 330a, 330b, 330d: left wing weight part (weight body)
340, 340a, 340b, 340d: right wing weight part (weight body)
400, 400d: Pedestal 401: Pedestal first layer 402: Pedestal second layer 403: Pedestal third layer 410, 410d: First wall 420, 420d: Second wall 430, 430d: Third wall 440, 440d : Fourth wall 445d: fitting groove 500: power generation circuit 600: device housing 610: base substrate 620: upper lid substrate 630: side wall plate 700d: main power generation component 710d: first member 711d: bridge portion piezoelectric layer 712d: plate Bridge portion 720d: second member 721d: central piezoelectric layer 722d: central plate portion 730d: third member 731d: connecting portion piezoelectric layer 732d: pedestal connecting portion 1000: laminated material block 1001: material first layer 1002: material first 2nd layer 1003: Material 3rd layer B: Bonding pad Cf: Smoothing capacitive element (capacitor)
D0 (+) to D4 (+): Positive charge rectifier (diode)
D0 (−) to D4 (−): negative charge rectifier (diode)
d1 to d10: Actual dimensions of each part d11 to d18: Gaps dimension d19: Actual dimensions of each part E0: Lower layer electrode E1: Tip left upper layer electrode E2: Tip right upper layer electrode E3: Root end left upper layer electrode E4: Root end Upper right layer electrode Fx: Force in the X-axis direction Fy: Force in the Y-axis direction Fz: Force in the Z-axis direction G, Ga, Gb: Center of gravity H of the weight body, H ': Boundary lines L1, L2, L3: Longitudinal axis L1 ′: Longitudinal axis MGS: Main power generation structure MGSa: Main power generation structure MGSb: Main power generation structure MGSd: Main power generation structure O: Origin of the XYZ three-dimensional coordinate system (root end)
P1: tip left piezoelectric element P2: tip right piezoelectric element P3: root left piezoelectric element P4: root right piezoelectric elements PGE, PGE ', PGEd: power generation elements T, T': tip (tip)
X: coordinate axis X ′ of the XYZ three-dimensional coordinate system X: axis parallel to the X axis Y: coordinate axis Z of the XYZ three-dimensional coordinate system Z: coordinate axis ZL of the XYZ three-dimensional coordinate system: loads θ1 to θ4 of the device to which power is supplied Angle of bridge

Claims (8)

A power generating element that generates power by converting vibration energy into electrical energy,
A plate-like bridge portion extending along a predetermined longitudinal axis and having flexibility;
A pedestal for supporting and fixing a root end portion of the plate-like bridge portion;
A weight body indirectly connected to the tip of the plate-like bridge portion;
A piezoelectric element fixed at a predetermined position where expansion and contraction of the surface of the plate-like bridge portion occurs; and
With
The weight body has a left wing weight portion located on the left side of the plate-like bridge portion with respect to the longitudinal axis, and a right wing weight portion located on the right side of the plate-like bridge portion with respect to the longitudinal direction axis. And having
A weight body support portion is connected to a tip portion of the plate-like bridge portion, the weight body is connected to a lower surface of the weight body support portion, and the center of gravity of the weight body is a plate-like bridge portion. A power generating element, which is located below the power generator. The power generating element according to claim 1 ,
A base connecting portion extending along an axis orthogonal to the longitudinal axis is connected to a root end portion of the plate-like bridge portion, and the base connecting portion is fixed to the base. The power generating element according to claim 1 or 2 ,
When the pedestal forms an annular structure surrounding the plate-shaped bridge portion and the weight body, and an acceleration exceeding a predetermined size acts on the power generation element, a part of the weight body is the annular structure body. A power generating element that is in contact with a part of the power source and further displacement is limited. In the electric power generating element in any one of Claims 1-3 ,
A piezoelectric element is disposed on the left side in the vicinity of the tip of the plate-like bridge portion, the left-side piezoelectric element on the tip, the right-side tip of the piezoelectric element in the vicinity of the tip of the plate-like bridge, and a plate-like bridge A power generation comprising: a root end left side piezoelectric element disposed on the left side in the vicinity of the root end part of the plate; and a root end right side piezoelectric element disposed on the right side in the vicinity of the root end part of the plate-like bridge portion. element. In the electric power generating element in any one of Claims 1-4 ,
Piezoelectric elements are locally formed on the surface of the piezoelectric material layer, the lower layer electrode layered on the surface of the plate-like bridge portion, the piezoelectric material layer layered on the surface of the lower layer electrode, and And a piezoelectric material layer having a property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction. In the electric power generating element in any one of Claims 1-5 ,
A power generation element further comprising a power generation circuit that rectifies a current generated based on electric charges generated in the piezoelectric element and extracts electric power. A power generation device comprising: the power generation element according to claim 6 ; and a device housing that houses the power generation element.
When the pedestal of the power generating element is fixed to the device casing and an external force that vibrates the device casing is applied, the weight body of the power generating element vibrates in the device casing due to the bending of the plate-like bridge portion. And generating electric power extracted from the power generation circuit in response to the vibration. A power generation device comprising: the power generation element according to claim 6 ; and a device housing that houses the power generation element.
When a weight body of the power generation element is fixed to the device housing and an external force that vibrates the device housing is applied, the base of the power generation device vibrates in the device housing due to the bending of the plate-like bridge portion. And generating electric power extracted from the power generation circuit in response to the vibration.

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