JP6841447B2 - 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 electrical energy.

In order to make effective use of limited resources, technologies for converting various forms of energy into electrical energy and extracting it have been proposed. One of them is a technique of converting vibration energy into electrical energy and extracting it. For example, in Patent Document 1 below, layered piezoelectric elements are laminated to form a piezoelectric element for power generation, and the piezoelectric element for power generation is subjected to an external force. A piezoelectric type power generation element that vibrates and generates power is disclosed. Further, Patent Document 2 discloses a power generation element having a MEMS (Micro Electro Mechanical System) structure using a silicon substrate.

On the other hand, in Patent Document 3, a hammer head type structure in which the weight body is supported by a cantilever with one end fixed is used, and the weight body constituting the head portion is vibrated and arranged in the handle portion. A type of power generation element that generates power by a piezoelectric element for power generation is disclosed. Further, Patent Document 4 discloses a power generation element using this hammer head type structure and a piezoelectric element using a structure in which a weight body is supported by an L-shaped bent plate-shaped bridge portion. ..

The basic principle of these power generation elements is that the vibration of the weight body causes the piezoelectric element to periodically bend, and the electric charge generated based on the stress applied to the piezoelectric element is taken out to the outside. If such a power generation element is mounted on, for example, an automobile, a train, a ship, or the like, it becomes possible to take out the vibration energy applied during transportation as electric energy. It can also be attached to a vibration source such as a refrigerator or air conditioner to generate electricity.

Japanese Unexamined Patent Publication No. 10-2436667 Japanese Unexamined Patent Publication No. 2011-152010 U.S. Patent Publication No. 2013/0154439 WO2015 / 033621A

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

Further, in the power generation element using the plate-shaped bridge portion as 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-shaped bridge portion as long and thin as possible. Therefore, when excessive vibration is applied, the plate-shaped bridge portion may be damaged.

Therefore, the present invention has a simple structure, but it is possible to obtain high power generation efficiency by converting vibration energy containing various directional components into electric energy without waste, and excessive vibration is added. An object of the present invention is to provide a power generation element that is not easily damaged even in such a case.

(1) The first aspect of the present invention is in a power generation element that generates power by converting vibration energy into electrical energy.
A plate-shaped bridge that extends along the first longitudinal axis and has flexibility,
A pedestal that supports and fixes the root end of the plate-shaped bridge,
With a weight body directly or indirectly connected to the tip of the plate-shaped bridge,
Piezoelectric elements fixed in place where the surface of the plate-shaped bridge is stretched and deformed,
A power generation circuit that rectifies the current generated based on the electric charge generated in the piezoelectric element and extracts electric 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-shaped bridge portion and a right wing weight portion located on the right side with respect to the longitudinal axis of the plate-shaped bridge portion. It is something like that.

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

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

(5) A fifth aspect of the present invention is 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 connecting portion extending along a third longitudinal axis orthogonal to the first longitudinal axis is connected to the root end of the plate-shaped bridge portion, and this pedestal connecting portion is fixed to the pedestal. ..

(7) A seventh aspect of the present invention is the power generation element according to the first to sixth aspects described above.
The pedestal is composed of a plate-shaped bridge portion and an annular structure that surrounds the circumference of the weight body, and when an acceleration exceeding a predetermined magnitude is applied to the power generation element, a part of the weight body has this annular structure. It is designed to come into contact with a part of the body and limit further displacement.

(8) An eighth aspect of the present invention is the power generation element according to the first to seventh aspects described above.
The piezoelectric element is the tip left side piezoelectric element arranged on the left side near the tip of the plate-shaped bridge, the tip right side piezoelectric element arranged on the right side near the tip of the plate-shaped bridge, and the plate-shaped bridge. It has a piezoelectric element on the left side of the root end located on the left side near the root end of the bridge and a piezoelectric element on the right side of the root end arranged on the right side near the root end of the plate-shaped bridge. ..

(9) A ninth aspect of the present invention is the power generation element according to the first to eighth aspects described above.
A plurality of piezoelectric elements are locally formed on the surface of the lower layer electrode formed in a layer on the surface of the plate-shaped bridge portion, the piezoelectric material layer formed in a layer on the surface of the lower layer electrode, and the surface of the piezoelectric material layer. It is composed of an upper layer electrode group composed of upper layer electrodes, and as a piezoelectric material layer, 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 is used.

(10) A tenth aspect of the present invention is a power generation device configured by accommodating the power generation element according to the first to ninth aspects described above in the device housing.
The pedestal of the power generation element is fixed to the device housing, and when an external force that vibrates the device housing is applied, the weight body of the power generation element vibrates in the device housing due to the bending of the plate-shaped bridge portion, and the vibration is caused. The power taken out from the power generation circuit is output according to the above.

(11) An eleventh aspect of the present invention is a power generation device configured by accommodating the power generation element according to the first to ninth aspects described above in the device housing.
The weight body 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 element vibrates in the device housing due to the bending of the plate-shaped bridge portion, and the vibration is caused. The power taken out from the power generation circuit is output according to the above.

(12) A twelfth aspect of the present invention is in a power generation element that generates power by converting vibration energy in each coordinate axis direction into electrical energy in the XYZ three-dimensional coordinate system.
When the XY plane is a horizontal plane and the Z-axis positive direction is upward and the Z-axis negative direction is downward, the main power generation first layer, main power generation second layer, and main power generation third layer are laminated in order from the top. Main power generation structure and
A pedestal that supports and fixes a predetermined location in the main power generation structure,
A power generation circuit that rectifies the current generated based on the electric charge generated by the main power generation structure and extracts power.
Provided
The second main power generation layer is a flat plate-like layer arranged along a plane parallel to the XY plane, and supports a flexible plate-shaped bridge portion arranged on the Y axis and the third main power generation layer. With a weight body support for
The weight body support portion has a central plate-like portion arranged on the X'axis, which is an axis that intersects the Y axis and is parallel to the X axis.
The plate-shaped bridge extends from the root end to the tip along the Y-axis, the central plate-shaped part extends along the X'axis so as to intersect the Y-axis, and intersects the Y-axis of the central plate-shaped part. The tip of the plate-shaped bridge is connected near the part, and the XY plane projection image of the plate-shaped bridge and the central plate is T-shaped.
The first layer of the main power generation has a piezoelectric element formed so as to cover at least a part of the upper surface of the plate-shaped bridge portion of the second layer of the main power generation.
The third layer of the main power generation is connected to the lower surface of the weight body support portion of the second layer of the main power generation, and has a mass sufficient to cause the plate-shaped bridge portion to bend based on the applied acceleration. Functions as a weight
Regarding both sides of the plate-shaped bridge, 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 third layer of the main power generation is the plate-shaped bridge part. 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-shaped bridge,
The power generation circuit is a circuit that extracts electric power by rectifying the current generated based on the electric charge generated in the piezoelectric element.

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

(14) A fourteenth aspect of the present invention is the power generation element according to the twelfth or thirteenth aspect described above.
The third layer of the main power generation 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. The XY plane projection image of the weight body having the right wing weight portion and the central weight portion is formed in a "U" shape.

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

(16) A sixteenth aspect of the present invention is the power generation element according to the twelfth to fifteenth aspects described above.
The main power generation structure is plane-symmetrical 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-shaped bridge portion.

(17) A seventeenth aspect of the present invention is 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 becomes the entire area of the upper surface of the main power generation second layer. It is made to be joined.

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

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

(20) A twentieth aspect of the present invention is the power generation element according to the nineteenth aspect described above.
The upper layer electrode group has a tip left upper layer electrode, a tip right upper layer electrode, a root end left upper layer electrode, and a root end right upper layer electrode.
The projected image of the upper left upper electrode of the tip on the upper surface of the second layer of the main power generation extends in the direction parallel to the Y axis, and is located on the side where the X coordinate value near the tip of the plate-shaped bridge becomes negative.
The projected image of the upper right upper layer electrode on the right side of the tip extends in the direction parallel to the Y axis, and is located on the side where the X coordinate value near the tip of the plate-shaped bridge is positive.
The projected image of the upper electrode on the left side of the root end on the upper surface of the second layer of the main power generation extends in the direction parallel to the Y axis, and is located on the side where the X coordinate value near the root end of the plate-shaped bridge becomes negative.
The projected image of the upper electrode on the right side of the root end on the upper surface of the second layer of the main power generation extends in the direction parallel to the Y axis, and is located on the side where the X coordinate value near the root end of the plate-shaped bridge is positive. It is the one that was made.

(21) The 21st aspect of the present invention is the power generation element according to the 19th or 20th aspect described above.
The power generation circuit includes a capacitance element, a positive charge rectifying element whose forward direction is from each upper layer electrode toward the positive electrode side of the capacitance element in order to guide the positive charge generated in each upper layer electrode to the positive electrode side of the capacitance element. It has 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 generated electrical energy is smoothed by a capacitive element and supplied.

(22) The 22nd aspect of the present invention is the power generation element according to the 19th to 21st aspects described above.
The piezoelectric material layer of the main power generation first layer is composed of a piezoelectric thin film, the upper and lower electrodes of the main power generation first layer are composed of a metal layer, the main power generation second layer is composed of a silicon substrate, and the main power generation third layer. The layer is made of a metal substrate, a ceramic substrate, or a glass substrate.

(23) The 23rd aspect of the present invention is the power generation element according to the 12th to 22nd aspects described above.
The pedestal forms an annular structure that surrounds the main power generation structure along the XY plane, and when a horizontal component of acceleration exceeding a predetermined magnitude acts on the power generation element, the main power generation third layer has an annular structure. It is designed to come into contact with the inner surface of the body and limit further displacement.

(24) The 24th aspect of the present invention is the power generation element according to the 23rd aspect described above.
The pedestal forms a rectangular rectangular structure having four sets of wall portions, that is, a first wall portion, a second wall portion, a third wall portion, and a fourth wall portion.
The first wall portion is arranged adjacent to the main power generation structure on the negative direction side of the X axis, and constitutes a wall surface along a plane parallel to the YZ plane.
The second wall portion is arranged adjacent to the main power generation structure on the positive direction side of the X axis, and constitutes a wall surface along a plane parallel to the YZ plane.
The third wall portion is arranged adjacent to the main power generation structure on the positive direction side of the Y axis, 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 negative direction side of the Y axis, and constitutes a wall surface along a plane parallel to the XZ plane.
The root end of the plate-shaped bridge is supported and fixed to the fourth wall.

(25) The 25th aspect of the present invention is the power generation element according to the 23rd or 24th aspect described above.
The pedestal is composed of a laminated structure in which the pedestal 1st layer, the pedestal 2nd layer, and the pedestal 3rd layer are laminated in order from the top, and the pedestal 1st layer is the main power generation 1st layer near the root end of the plate-shaped bridge. The second layer of the pedestal is connected to the second layer of the main power generation at the root end of the plate-shaped bridge.

(26) A twenty-sixth aspect of the present invention is the power generation element according to the 23rd or 24th aspect described above.
The second layer of the main power generation further has a pedestal connection portion connected to the root end portion of the plate-shaped bridge portion.
The pedestal connection 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 the predetermined portion of the pedestal, and the pedestal connection portion is fixed in a state of being fitted in the fitting groove. ..

(27) A 27th aspect of the present invention is a power generation device configured by accommodating the power generation element according to the 12th to 26th aspects described above in the device housing.
The pedestal of the power generation element is fixed to the device housing so that when an external force that vibrates the device housing acts, the main power generation third layer of the power generation element vibrates in the device housing due to the bending of the plate-shaped bridge portion. The electric power taken out from the power generation circuit is output in response to the vibration.

(28) The 28th aspect of the present invention is the power generation device according to the 27th aspect described above.
The device housing is arranged so as to surround the base substrate for supporting and fixing the power generation element from below, the upper lid substrate that covers the upper part of the power generation element, and the periphery of the power generation element, and the side wall that connects the base substrate and the upper lid substrate. With a board,
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 upper surface of the base substrate. A lower gap is formed between the two
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 acts on 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 lid substrate, and further displacement is restricted. It is made to be.

(29) A 29th aspect of the present invention is a power generation device configured by accommodating the power generation element according to the 12th to 26th aspects described above in the device housing.
The main power generation third layer of the power generation element is fixed to the device housing so that the pedestal of the power generation element vibrates in the device housing due to the bending of the plate-shaped bridge portion when an external force that vibrates the device housing acts. The electric power taken out from the power generation circuit is output in response to the vibration.

(30) A thirtieth aspect of the present invention is the power generation device according to the twenty-ninth aspect described above.
The device housing is arranged so as to surround the base substrate for supporting and fixing the power generation element from below, the upper lid substrate that covers the upper part of the power generation element, and the periphery of the power generation element, and the side wall that connects the base substrate and the upper lid substrate. With a board,
The bottom surface of the pedestal of the power generation element is located above the bottom surface of the third layer of the main power generation of the power generation element, and the bottom surface of the third layer of the main power generation is fixed to the upper surface of the base substrate. A lower gap is formed between the two
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 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 restricted. It was done.

(31) In the 31st aspect of the present invention, the structure for the power generation element is configured by the elements excluding the power generation circuit from the power generation elements according to the 1st to 9th and 12th to 26th aspects described above. It was done.

In the power generation element according to the present invention, a cantilever structure is adopted in which the root end portion of a flexible plate-shaped bridge portion is fixed to a pedestal and a weight body is connected to the tip portion, and the plate-shaped bridge portion is fixed to the plate-shaped bridge portion. Power is generated by the generated piezoelectric element. Moreover, since the weight body has a left wing weight portion located on the left side of the plate-shaped bridge portion and a right wing weight portion located on the right side, the weight body has various directions with respect to the plate-shaped bridge portion. The external force to bend can be efficiently transmitted. 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-shaped bridge even when excessive vibration is applied, and the plate-shaped bridge is damaged. Can be prevented.

As described above, according to the present invention, it is possible to obtain high power generation efficiency by converting vibration energy containing various directional components into electric energy without waste, even though it has a simple structure, and it is excessive. It is possible to realize a power generation element that is not easily damaged even when the vibration of the above is applied.

It is a perspective view which shows the structure of the power generation element PGE which concerns on the basic embodiment of this invention (the three-layer part which constitutes the main power generation structure MGS is shown separately) and the block diagram. It is a top view of the main power generation first layer 100 of the main power generation structure MGS shown in FIG. It is a top view of the main power generation second layer 200 of the main power generation structure MGS shown in FIG. It is a top view of the main power generation third layer 300 of the main power generation structure MGS shown in FIG. 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 the main power generation structure MGS shown in FIG. 1 is fixed to a pedestal 400 (hatching is for showing the formation area of each upper layer electrode and the fixed state by a pedestal, and does not show the cross section. The numbers in parentheses indicate the components located below.) It is a side cross-sectional view which shows the state which the main power generation structure MGS shown in FIG. 1 is fixed to a pedestal 400 (showing the cross section cut in the YZ plane). It is a top view which shows the deformation mode when the force + Fx in the positive direction of the X-axis is applied to the main power generation structure MGS shown in FIG. FIG. 5 is a side sectional view showing a deformation mode when a force + Fy in the positive direction of the Y axis is applied to the main power generation structure MGS shown in FIG. 1 (showing a cross section cut in a YZ plane). It is a side cross-sectional view which shows the deformation mode when the force + Fz in the Z-axis positive direction is applied to the main power generation structure MGS shown in FIG. 1 (shows the cross section cut in the YZ plane). 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. It is a table which shows the polarity of the charge generated in the upper layer electrodes E1 to E4 when the 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. 6 is a stress distribution diagram showing the Y-axis stress generated in the piezoelectric material layer 105 when a force + Fx in the positive direction of the X-axis acts on the weight of the main power generation structure MGS shown in FIG. 1. 6 is a stress distribution diagram showing the Y-axis stress generated in the piezoelectric material layer 105 when a force + Fy in the positive Y-axis direction is applied to the weight body of the main power generation structure MGS shown in FIG. 1. It is a stress distribution diagram which shows the Y-axis direction stress generated in the piezoelectric material layer 105 when the Z-axis positive direction force + Fz is applied to the weight body of the main power generation structure MGS shown in FIG. It is a circuit diagram which shows the specific structure of the power generation circuit 500 of the power generation element PGE shown in FIG. It is a top view which shows the power generation element PGE which used the rectangular annular structure as a pedestal 400 (the power generation circuit is not shown). FIG. 5 is a normal cross-sectional view showing a cross section of the power generation element PGE shown in FIG. 17 cut along a cutting line 18-18. FIG. 5 is a side sectional view showing a cross section of the power generation element PGE shown in FIG. 17 cut along a cutting line 19-19. FIG. 5 is a side sectional view showing a cross section of the power generation element PGE shown in FIG. 17 cut along the cutting line 20-20. FIG. 6 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. It is a side sectional view of the power generation device configured by accommodating the power generation element PGE shown in FIG. 17 in the device housing 600. FIG. 22 is a side sectional view of the power generation device according to a modified example in which the roles of the weight body and the pedestal are reversed in the power generation device shown in FIG. It is a top view which shows the 1st modification A of the main power generation structure MGS shown in FIG. 1 (the reference numerals in parentheses indicate the component of the main power generation second layer 200a arranged below). .. It is a top view which shows the 2nd modification B of the main power generation structure MGS shown in FIG. 1 (the reference numerals in parentheses indicate the component of the main power generation 2nd layer 200b arranged below). .. It is a top view which shows the connection angle of both ends of the plate-shaped bridge part 210 in the main power generation 2nd layer 200 of the main power generation structure MGS shown in FIG. It is a top view which shows the 2nd layer 200c of the main power generation which concerns on the 3rd modification C of the main power generation structure MGS shown in FIG. It is a top view (FIG. (A)) and a normal sectional view (FIG. (B)) which show the main power generation component 700d used for the 4th modification D of the main power generation structure MGS shown in FIG. In Figure (a), the numbers in parentheses indicate the components of each layer. It is a top view which shows the weight body 300d used for the 4th modification D of the main power generation structure MGS shown in FIG. It is a top view which shows the pedestal 400d for fixing the 4th modification D of the main power generation structure MGS shown in FIG. FIG. 3 is a top view showing a state in which the main power generation component 700d shown in FIG. 28 and the weight body 300d shown in FIG. 29 are attached to the pedestal 400d shown in FIG.

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

<<< §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 generation element PGE (abbreviation of Power Generating Element) according to a basic embodiment of the present invention. As shown in the perspective view, this power generation element PGE has a three-layer structure in which the first layer 100, the second layer 200, and the third layer 300 are laminated. The perspective view of FIG. 1 shows a state in which these three layers are separated into upper and lower layers for convenience of explanation, but in reality, the upper surface of the second layer 200 is fixed to the lower surface of the first layer 100, and the second layer 200 is fixed. The upper surface of the third layer 300 is fixed to the lower surface of the third layer 300, and the three layers form a structure joined 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 the "main power generation first layer", and the second layer 200 is the "main power generation first layer". 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 a simple symbol symbol in the figure) and a power generation circuit 500 (indicated by a block in the figure) to the main power generation structure MGS composed of the three layers. It is composed of.

The pedestal 400 plays a role of supporting and fixing a part (right end surface in the figure) of the main power generation structure MGS, and the 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, but each layer constituting the pedestal 400 is "pedestal". We will call them "first layer", "pedestal second layer", and "pedestal third layer" to distinguish them.

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, and the X axis is in the back direction, the Y axis is in the left direction, and the Z axis is in the upward direction. By taking, the XYZ three-dimensional Cartesian coordinate system is defined. In the following description of the present application, as shown in the drawing, the vertical relationship between each component will be described on the premise 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 laminated in this order from the top.

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

The main power generation first layer 100 is a flat plate-like structure having an "E" -shaped plane shape, and its main portion is composed of a piezoelectric material layer 105. More specifically, the main power generation first layer 100 consists of three layers: a piezoelectric material layer 105, upper layer electrodes E1 to E4 formed in a predetermined region on the upper surface thereof, and lower layer electrodes E0 formed in the entire lower surface region. It is composed of structures. 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 electric charges are generated in the upper layer electrodes E1 to E4 and the lower layer electrodes E0.

The lower layer electrodes E0 are one common electrode formed on the entire lower surface of the piezoelectric material layer 105, whereas the upper layer electrodes E1 to E4 are stations formed in each predetermined region of the piezoelectric material layer 105. Depending on the direction of the external force acting on the electrode, the direction of stress applied to each part of the piezoelectric material layer 105 (compression direction stress or extension direction stress) may differ, and the polarity of the generated charge may differ. Because there is.

The power generation circuit 500 has a function of rectifying the current generated based on the electric charge generated in this way and extracting electric power. The electric power generated by the power generation element PGE will be supplied to the outside from the power generation circuit 500. In FIG. 1, for convenience of illustration, 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, but in reality, between the upper layer electrodes E2 to E4 and the power generation circuit 500. The same wiring is done for.

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, and is a two-dimensional plan view in which the X axis is in the right direction of the figure and the Y axis is in the upper direction of the figure. Has been done. The X-axis, Y-axis, and 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, four upper layer electrodes E1 to E4 are formed on the upper surface of the piezoelectric material layer 105 having an "E" shape, and one lower layer electrode E0 (FIG. 2) is formed on the lower surface. It does not appear in).

The piezoelectric material layer 105 is actually a single plate-shaped integrated structure having an "E" shape, but here, for convenience of explanation, four portions 110, 120, 130, 140 as shown in the figure. I will consider it separately. Each portion is composed of a flat plate-shaped 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 (point defined on the Y axis) along the Y axis. All of the four upper layer electrodes E1 to E4 are arranged on the upper surface of the bridge portion piezoelectric layer 110. Actually, the upper layer electrodes E1 to E4 and the lower layer electrodes 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 intersecting the Y axis and 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 will be referred to as a central piezoelectric layer. The bridge portion piezoelectric layer 110 and the central piezoelectric layer 120 form a structure having a T-shaped plane shape.

The portion 130 is a wing-shaped portion extending from the left side of the central piezoelectric layer 120 to the lower side of the drawing and arranged on the left side of the bridge portion piezoelectric layer 110. Here, this portion 130 will be referred to as a left wing piezoelectric layer 130. To do. On the other hand, the portion 140 is a wing-shaped portion extending from the right side of the central piezoelectric layer 120 to the lower side of the drawing and arranged on the right side of the bridge portion piezoelectric layer 110, and here, this 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, since the left and right are defined with the top view in which the Y axis is drawn in the vertical direction in mind, 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 arranged on the left side of the bridge portion piezoelectric layer 110, and the right wing piezoelectric layer 140 is arranged on the right side of the bridge portion piezoelectric layer 110. Of course, such a definition of left and right is a definition for convenience for explaining the relative positional relationship with respect to the YZ plane, and has no absolute meaning.

In FIG. 2, the lower end (near the origin O) of the bridge portion piezoelectric layer 110 extends downward with respect to the lower end of the left wing piezoelectric layer 130 and the lower end of the right wing piezoelectric layer 140, which is shown in FIG. This is because, as shown in the perspective view, the vicinity of the origin O of the second layer of the main power generation is connected to the pedestal 400. 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 this stress concentration portion, more efficient power generation becomes possible.

FIG. 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 is also a two-dimensional plan view in which the X axis is in the right direction of the figure and the Y axis is in the upper 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 inside the main power generation second layer 200 (intermediate position in the thickness direction).

The main power generation second layer 200 is also a plate-shaped structure having an "E" shape, and in the case of the basic embodiment shown here, the XY plane projection image of the main power generation first layer 100 shown in FIG. , The XY plane projection image of the main power generation second layer 200 shown in FIG. 3 has the same shape, 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. There is. Therefore, as for the main power generation second layer 200, four portions 210, 220, 230, 240 can be defined as in the main power generation first layer 100. Each portion is composed of flat plate-like layers arranged along a plane parallel to the XY plane. Of course, in reality, the main power generation second layer 200 is a single plate-shaped integrated structure in the shape of an "E", and the above four parts are individual plate-shaped integrated structures. This is for convenience to explain by dividing into sections.

First, the portion 210 is a portion arranged on the Y-axis and having a flexible bridge structure, and here, this portion 210 will be referred to as a plate-shaped bridge portion 210. The plate-shaped bridge portion 210 is a thin beam-shaped structure extending from the origin O to the tip point T (one point on the Y-axis) along the Y-axis, and has various flexibility. It has the property of deforming in various directions. Here, for convenience of explanation, the vicinity of the origin O of the plate-shaped bridge portion 210 is referred to as a root end portion, and the vicinity of the tip point T is referred to as a tip portion. The plate-shaped bridge portion 210 is an elongated plate-shaped member extending along the Y-axis from the root end portion to the tip portion.

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

The bridge portion piezoelectric layer 110 shown in FIG. 2 is fixed to the upper surface of the plate-shaped bridge portion 210 shown in FIG. As will be described later, the plate-shaped 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. An electric charge will be generated.

On the other hand, the portions 220, 230, 240 (the portion of the main power generation second layer 200 excluding the plate-shaped bridge portion 210) are collectively referred to as a weight body support portion here. As shown in the figure, the weight body support portion is connected to the plate-shaped bridge portion 210 at the tip point T. The role of this weight body support portion is to literally support the weight body (main power generation third layer 300) and transmit the vibration of the weight body to the tip portion (near the tip point T) of the plate-shaped bridge portion 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-shaped portion 220, a left wing plate-shaped portion 230, and a right wing plate-shaped portion 240.

The central plate-shaped portion 220 is an elongated plate-shaped member arranged on the X'axis, which intersects the Y-axis and is parallel to the X-axis, and extends along the X'axis so as to intersect the Y-axis. There is. The central portion of the central plate-shaped portion 220 is connected to the tip portion of the plate-shaped bridge portion 210 at the position of the tip point T. That is, the tip of the plate-shaped bridge portion 210 is connected in the vicinity of the portion of the central plate-shaped portion 220 that intersects the Y-axis. As a result, the XY plane projection image of the plate-shaped bridge portion 210 and the central plate-shaped portion 220 has a T-shape. The central piezoelectric layer 120 shown in FIG. 2 is fixed to the upper surface of the central plate-shaped portion 220 shown in FIG.

On the other hand, the left wing plate-shaped portion 230 is a plate-shaped member extending from the left side of the central plate-shaped portion 220 to the left side of the plate-shaped bridge portion 210 along the direction parallel to the Y-axis, and the right wing plate-shaped portion 240 is the center. It is a plate-shaped member extending from the right side of the plate-shaped portion 220 to the right side of the plate-shaped 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-shaped 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-shaped portion 240 shown in FIG. ..

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

FIG. 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 is also a two-dimensional plan view in which the X axis is in the right direction of the figure and the Y axis is in the upper 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 body support portions 220, 230, 240 shown in FIG. 3, and is sufficient to cause the plate-shaped bridge portion 210 to bend based on the applied acceleration. It functions as a weight body with mass. This weight body plays a role of causing vibration by the action of a force based on the acceleration applied from the outside, and causing elastic deformation that fluctuates with time with respect to the plate-shaped bridge portion 210.

In the case of the basic embodiment shown here, the main power generation third layer 300 (weight body) is composed of a central weight portion 320, a left wing weight portion 330, and a right wing weight portion 340 as shown in FIG. There is. The central weight portion 320 is an elongated portion extending along the X'axis (the axis intersecting the Y axis and parallel to the X axis), and serves to connect 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 for both sides of the plate-shaped bridge portion 210, the left wing weight portion 330 Is a weight body extending from the left side of the central weight portion 320 to the left side of the plate-shaped bridge portion 210 along a direction parallel to the Y axis, and the right wing weight portion 340 is from the right side of the central weight portion 320. It is a weight body extending to the right side of the plate-shaped bridge portion 210 along a direction parallel to the Y axis.

The central weight portion 320 shown in FIG. 4 is fixed to the lower surface of the central plate-shaped 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-shaped portion 230 shown in FIG. The right wing weight portion 340 shown in FIG. 4 is fixed to the lower surface of the right wing plate-shaped portion 240 shown in FIG. After all, the XY plane projection image of the weight body having the left wing weight portion 330, the central weight portion 320, and the right wing weight portion 340 has a "U" shape. In the main power generation third layer 300, the hollow portion 310 is formed at a position directly below the plate-shaped bridge portion 210. The presence of the hollow portion 310 allows the plate-shaped bridge portion 210 to be displaced downward (in the negative direction of the Z axis).

Actually, the main power generation third layer 300 is an integrated structure having a "U" shape, and the above three parts are for convenience for explaining the integrated structure by dividing it 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 reality, 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 a three-layer structure in which they are joined to each other in a vertically stacked state. To configure. For bonding each layer, for example, adhesion using an adhesive may be performed (as described later, layer formation may be performed by a method such as printing, thin film deposition, or sputtering). FIG. 5 is a side view of the main power generation structure MGS in such a laminated state when observed from the negative X-axis direction to the positive X-axis direction. Therefore, the origin O of the coordinate system is located at the right end of the figure, the vertical back direction of the paper surface of the figure is the positive direction of the X axis, the left direction of the figure is the positive direction of the Y axis, and the upper direction of the figure is the positive direction of the Z axis.

In FIG. 5, in the portion of the second layer 200 of the main power generation, the root end portion of the plate-shaped bridge portion 210 is shown in the vicinity of the origin O, and the central plate-shaped portion located in front of the plate-shaped bridge portion 210. 220 and the left wing plate 230 are observed. In the portion of the main power generation first layer 100 located above the main power generation second layer 200, a bridge portion piezoelectric layer 110, a central piezoelectric layer 120, and a left wing piezoelectric layer 130 are observed on the upper surface of the lower electrode E0, and further. Upper layer electrodes E1 and E3 are observed on the upper surface thereof (upper layer electrodes E2 and E4 are hidden behind the upper layer electrodes E2 and E4). Further, as a 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-shaped bridge portion 210 projecting to the right side of the drawing will be fixed to a pedestal 400 (not shown).

As shown in the figure, 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 second layer 200 of the main power generation, the third layer 300 of the main power generation (a "U-shaped weight body") is joined, and when the weight body is displaced based on the applied acceleration. , The second layer 200 of the main power generation (particularly, the portion of the plate-shaped bridge portion 210) is bent, and the portion of the first layer 100 of the main power generation (particularly, the piezoelectric layer 110 of the bridge portion) formed on the upper surface thereof is also bent. Is transmitted, and charges are generated in the upper electrode E1 to E4 and the lower electrode E0.

FIG. 6 is a top view showing a state in which the main power generation structure MGS shown in FIG. 1 is fixed to the pedestal 400. The hatching in the figure is for showing the formation region of each upper layer electrode and the fixed state by the pedestal, and does not show the cross section. In addition, the reference numerals in parentheses indicate the components arranged below. Here, paying attention 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.

Focusing on the arrangement of the four upper layer electrodes E1 to E4, the upper ends of the upper layer electrodes E1 and E2 are aligned with the boundary line H (the boundary line between the bridge portion piezoelectric layer 110 and the central piezoelectric layer 120). The upper electrodes E3 and E4 are arranged at positions where their lower ends are aligned with the lower ends of the bridge piezoelectric layer 110 (positions aligned with the X-axis). Further, the upper layer electrodes E1 and E3 are arranged on the left side of the bridge portion piezoelectric layer 110 (position where the X coordinate value becomes negative), and the upper layer electrodes E2 and E4 are arranged on the right side of the bridge portion piezoelectric layer 110 (the X coordinate value is positive). (Position to be).

Such a shape 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 (central piezoelectric layer 120, left wing piezoelectric layer 130, right wing piezoelectric layer 140) shown in FIG. 6, a "U" -shaped weight body support portion (central plate shape) is also formed. The portion 220, the left wing plate-shaped portion 230, the right wing plate-shaped portion 240) and the weight body (main power generation third layer: central weight portion 320, left wing weight portion 330, right wing weight portion 340) are joined. Then, when a force based on the vibration of the weight body acts in the vicinity of the tip point T (see FIG. 7 described later), the piezoelectric layer 110 of the bridge portion bends together with the plate-shaped bridge portion 210 which is the support layer thereof. Therefore, an electric charge is generated in each of the upper layer electrodes E1 to E4 according to the bending. The illustrated electrode arrangement is suitable for efficient charge generation (details will be described in §2). In this way, the current generated based on the electric charge generated by the main power generation structure MGS is rectified by the power generation circuit 500 and taken out as electric 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 obtained by cutting the main power generation structure MGS shown in FIG. 6 in the central YZ plane.

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

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

In the case of the illustrated embodiment, both the root end portion of the plate-shaped bridge portion 210 and the root end portion of the bridge portion piezoelectric layer 110 are joined to the pedestal 400 and supported and fixed to the pedestal 400. It is sufficient that at least the root end portion of the plate-shaped bridge portion 210 is supported and fixed. In short, the weight body may be supported by the pedestal 400 with a cantilever structure, and may be suspended in the air via the plate-shaped bridge portion 210.

Further, in the present application, the dimensional ratio of each part in the drawing is not necessarily the same as the dimensional ratio of the actual product, and for convenience, the drawing is drawn ignoring the actual dimensional ratio. Therefore, in FIGS. 6 and 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, if they constitute the power generation element PGE having a MEMS structure. Of course, the following dimensional examples are presented as one embodiment, and the dimensions of each part are not limited to the following dimensional 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 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 electrodes E0 and the upper layer electrodes E1 to E4 is 0.01 μm.

In general, the most efficient power generation is possible when the resonance frequency of the weight body, which is 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 structural design of the main power generation structure MGS, the design so that the resonance frequency matches the assumed frequency, that is, the dimensions of the above-mentioned parts are set. It is preferable to design with an appropriate value.

In general, the frequency of vibration 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 in particular, vibration in the range of 10 Hz to 50 Hz. Is often generated. Therefore, assuming that it is mounted on such a general device to generate power, the design is made so that the resonance frequency in each coordinate axis direction of the main power generation structure MGS is within the range of 10 Hz to 50 Hz. Is preferable.

In the above description, for convenience, only the portion of the main power generation third layer 300 is referred to as a weight body, but in reality, among the components of the main power generation structure MGS, the bridge portion piezoelectric layer 110 and the plate All parts except the bridge portion 210 play a role 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, and the central plate-shaped portion 220 and the left wing plate-shaped portion joined to these lower layers. The 230 and the right wing plate-shaped portion 240 (components of the second layer 200 of the main power generation) also contribute to the role of causing displacement at the tip point T, and thus also 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 to be larger than the thickness of the main power generation first layer 100 and the main power generation second layer 200, and the role as a weight body is The main power generation third layer 300 will be mainly responsible. Therefore, here, for convenience, the portion of the third layer 300 of the main power generation will be referred to as a weight body.

A feature of the power generation element PGE according to the present invention is that weight bodies are arranged on both the left and right sides of the plate-shaped bridge portion 210 constituting the main power generation structure MGS. That is, as is clear from the perspective view of FIG. 1, the weight body of the power generation element PGE according to the present invention is at least the plate-shaped bridge portion 210, as is clear from the projected image on the XY plane. It has 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-shaped bridge portion 210. Therefore, it is possible to efficiently transmit an external force that bends the plate-shaped bridge portion 210 in various directions. Further, as described in detail in §3, when excessive vibration is applied by providing a member that limits the displacement of the left wing weight portion 330 and the right wing weight portion 340 on the outside of the main power generation structure MGS. In addition, the displacement of the plate-shaped bridge portion 210 can be limited, and damage to the plate-shaped bridge portion can be prevented.

Further, in the basic embodiment shown here, since the plate-shaped bridge portion 210 is composed of the main power generation second layer 200 and the center of gravity is composed of the main power generation third layer 300 arranged below the main power generation second layer 200. The center of gravity G of the weight body (the structure constituting the third layer of the main power generation) is located below the plate-shaped bridge portion 210 at a predetermined distance. In FIGS. 6 and 7, the center of gravity G of the weight body is indicated by an x mark. In this way, if the main power generation structure MGS adopts a structure in which the center of gravity G of the weight body is arranged below the plate-shaped bridge portion 210 at a predetermined distance, each coordinate axis of the acceleration acting on the weight body is adopted. The plate-shaped bridge portion 210 can be efficiently bent based on the directional component, and efficient power generation becomes possible. In particular, it is preferable that the distance between the center of gravity G and the lower surface of the plate-shaped bridge portion 210 is as long as possible in order to increase the deflection of the plate-shaped bridge portion 210 with respect to the acceleration in the Y-axis direction.

In the case of the embodiment shown here, since the main power generation structure MGS has a structure symmetrical with respect to the YZ plane, the center of gravity of the structure (weight body) constituting the main power generation third layer 300 is plate-shaped. It is located on the YZ plane below the bridge portion 210. When a structure having such symmetry is adopted, the weight body can be stably vibrated in each coordinate axis direction, which is preferable in order to improve the power generation efficiency.

As the material of each layer constituting the main power generation structure MGS, any material may be used as long as it can fulfill the above-mentioned functions as each layer, but here, some examples of practically preferable materials may be used. I will list it.

First, since the main power generation first layer 100 only needs to be able to function as a piezoelectric element that generates electric charges based on stress applied from the outside, it is polarized in the thickness direction by the action of stress that expands and contracts in the layer direction. It suffices that electrodes are formed on both the upper and lower surfaces of the piezoelectric material layer 105 having the property of being generated. Specifically, the piezoelectric material layer 105 can be formed of, for example, a piezoelectric thin film such as PZT (lead zirconate titanate) or KNN (sodium niobate). Alternatively, a bulk piezoelectric element may be used. The electrodes E0 to E4 may be made of any conductive material, but in practice, they 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 needs to function as a support substrate for the main power generation first layer 100, and the portion of the plate-shaped bridge portion 210 needs to have flexibility. Silicon is the most suitable material to be used for such applications. Therefore, in the case of the embodiment described here, the second layer of the main power generation is composed of a silicon substrate. In the case of the example shown in FIG. 7, the thickness d9 of the second layer 200 of the main power generation is 200 μm, and the plate-shaped bridge portion 210 made of silicon having such a thickness is sufficiently flexible to generate power. Has sex.

Of course, it is also possible to use a metal substrate as the second layer 200 of the main power generation. In that case, since the upper layer portion of the metal substrate serves as the lower layer electrode E0, the piezoelectric thin film that becomes the main power generation first layer 100 is formed by forming a piezoelectric thin film on the metal substrate by the sputtering method or the sol-gel method. The element can be formed. Alternatively, a bulk piezoelectric material can be bonded onto the metal substrate. The upper layer electrode can be formed by printing, vapor deposition, sputtering, or the like on a metal material.

However, the inventor of the present application considers that the silicon substrate is the most suitable material for the second layer 200 of the main power generation at present. In general, when comparing the case where the piezoelectric element is formed on the upper surface of the metal substrate and the case where the piezoelectric element is formed on the upper surface of the silicon substrate by the current manufacturing process, the piezoelectric element of the latter is compared with the piezoelectric constant of the former. This is because the constant value is about three times larger, and the power generation efficiency of the latter is overwhelmingly higher. It is considered that this is because when the piezoelectric element is formed on the upper surface of the silicon substrate, the orientation of the crystals of the piezoelectric element is aligned. Further, if a silicon substrate is used as the second layer 200 of the main power generation, the power generation circuit 500 can be configured by using the 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, it may be configured by using a metal substrate such as SUS (iron), copper, or tungsten, a ceramic substrate, a glass substrate, or the like.

<<< §2. Power generation operation of power generation element according to the 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 a pedestal 400 and a power generation circuit 500 to the main power generation structure MGS composed of a three-layer structure, and is configured in each coordinate axis direction in the XYZ three-dimensional coordinate system. It has a function to generate electricity by converting vibration energy into electrical energy.

Therefore, here, the principle of power generation operation when the portion of the pedestal 400 is fixed to a moving automobile and a vibration component in each coordinate axis direction is added to the power generation element PGE will be described. To do. Therefore, the operation of this power generation element PGE will be described below assuming that the XYZ three-dimensional coordinate system is a coordinate system fixed to the pedestal 400 (that is, a transportation device) and the weight body vibrates in this coordinate system. To do.

FIG. 8 is a top view showing a deformation mode when a force + Fx in the positive direction of the X-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 −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 on the weight body as an inertial force. As a result, in the XYZ three-dimensional coordinate system, an external force + Fx that displaces in the positive direction of the X axis (to the right in the figure) acts on the weight body as shown by the white arrow in the figure.

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

Such bending deformation causes stretching stress as shown in the drawing with respect to each arrangement position of the four upper layer electrodes E1 to E4 of the bridge portion piezoelectric layer 110 in the direction along the Y axis. That is, with respect to the arrangement positions of the upper layer electrodes E1 and E4 of the bridge portion piezoelectric layer 110, compressive stress acts in the Y-axis direction as shown by the pair of arrows facing up and down (indicated by the letter "shrink" in a circle). As for the arrangement position of the upper layer electrodes E2 and E3 of the bridge portion piezoelectric layer 110, extensional stress acts in the Y-axis direction as shown by double-headed arrows with arrows at the top and bottom (in a circle with a "stretch" character). Show).

On the other hand, when the acceleration in the positive direction of the X-axis + αx acts on the pedestal 400, the acceleration −αx in the opposite direction acts on the weight body as an inertial force. As a result, in the XYZ three-dimensional coordinate system, an external force −Fx that displaces in the negative direction of the X axis (to the left in the figure) acts on the weight body, contrary to FIG. In this case, the mode of expansion and contraction of each part is reversed from that of FIG. That is, tensile stress acts on the arrangement positions of the upper layer electrodes E1 and E4 of the bridge portion piezoelectric layer 110, and compressive stress acts on the arrangement positions of the upper layer electrodes E2 and 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 positive direction of the Y axis 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 direction of the Y axis 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 opposite 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 displaces the weight in the positive direction of the Y axis (to the left in the figure) acts on the weight body as shown by the white arrow in the figure.

The external force + Fy acts as a force that displaces the center of gravity G of the weight body to the left in the figure. However, since the weight body is connected in the vicinity of the tip point T of the plate-shaped bridge portion 210, the weight body Tilts diagonally as shown in FIG. 9 (in FIG. 9, the left side goes up and the right side goes down). Therefore, as shown in FIG. 9, the plate-shaped bridge portion 210 and the bridge portion piezoelectric layer 110 formed on the upper surface thereof are curved and deformed so as to warp upward.

Such bending deformation causes stretching stress as shown in the drawing with respect to each arrangement position of the four upper layer electrodes E1 to E4 of the bridge portion piezoelectric layer 110 in the direction along the Y axis. That is, compressive stresses in the Y-axis direction act on all of the arrangement positions of the four upper layer electrodes E1 to E4 formed on the upper surface of the piezoelectric layer 110 of the bridge portion, as indicated by a pair of arrows facing each other to the left and right (circle). (Indicated by the letter "shrink").

On the other hand, when the acceleration + αy in the positive direction of the Y axis 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 displaces the weight in the negative direction of the Y axis (to the right in the figure) acts on the weight body, contrary to FIG. In this case, the weight body is inclined in the opposite manner to that of FIG. 9 (the left side is lowered and the right side is raised), and the expansion and contraction mode of each part is reversed from that of FIG. That is, the extension stress in the Y-axis direction acts on all 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 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 Z-axis negative acceleration −αz 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, the acceleration + αz in the opposite 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 displaces the weight in the positive direction of the Z axis (upward in the figure) acts on the weight body as shown by the white arrow in the figure.

The external force + Fz acts as a force that displaces the center of gravity G of the weight body upward in the figure. However, since the weight body is connected in the vicinity of the tip point T of the plate-shaped bridge portion 210, the plate-shaped bridge A force that displaces the tip of the portion 210 upward in the figure is applied. On the other hand, the root end portion (near the origin O) of the plate-shaped 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 keeping the root end portion of the plate-shaped bridge portion 210 in a fixed state, and the plate-shaped bridge portion 210 is formed on the plate-shaped bridge portion 210 and its upper surface. The bridge portion piezoelectric layer 110 is curved and deformed as shown in FIG.

Such bending deformation causes stretching stress as shown in the drawing with respect to each arrangement position of the four upper layer electrodes E1 to E4 of the bridge portion piezoelectric layer 110 in the direction along the Y axis. That is, with respect to the positions of the upper layer electrodes E1 and E2 arranged at the tip of the piezoelectric layer 110 of the bridge portion, extensional stress in the Y-axis direction acts as indicated by double-headed arrows with arrows on the left and right (circled). (Indicated by the letter "Shin"). On the other hand, at the positions of the upper layer electrodes E3 and E4 arranged at the root end of the piezoelectric layer 110 of the bridge portion, compressive stress acts in the Y-axis direction as shown by the pair of arrows facing each other on the left and right (circle). (Indicated by the letter "shrink").

On the other hand, when the acceleration in the positive direction of the Z axis + αz acts on the pedestal 400, the acceleration −αz in the opposite 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 displaces in the negative direction of the Z axis (downward in the figure) acts on the weight body, contrary to FIG. In this case, since the weight body moves to the lower part of the figure, the mode of expansion and contraction of each part is reversed from that of FIG. That is, compressive stress acts on the arrangement positions of the upper layer electrodes E1 and E2 of the bridge portion piezoelectric layer 110, and tensile stress acts on the arrangement positions of the upper layer electrodes E3 and E4 of the bridge portion piezoelectric layer 110.

FIG. 11 shows the upper electrode E1 of the bridge portion piezoelectric layer 110 when a force in each coordinate axis direction is applied to the weight body of the main power generation structure MGS shown in FIG. 1 based on the deformation modes of FIGS. 8 to 10. It is a table which shows the stretching stress in the Y-axis direction applied to the position of ~ E4. The figure is a table showing the stretching stress when the force + Fx, + Fy, + Fz in the positive direction of each coordinate axis is applied, but the stretching stress when the force -Fx, -Fy, -Fz in the negative direction of each coordinate axis is applied is , The compression / decompression relationship in this table is reversed.

As described in §1, in the power generation element PGE according to the basic embodiment, the main power generation first layer 100 has a lower layer electrode E0 formed in a layer 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 layers on the surface of the piezoelectric material layer 105 and an upper layer electrode group composed 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, as the piezoelectric material layer 105, when a stress extending in the layer direction acts, a positive charge is generated upward and a negative charge is generated downward, and when a stress compressing in the layer direction acts, a negative charge is generated upward and a positive charge is generated downward. Assuming that an electric charge is used, the polarity of the electric charge generated on the upper layer electrodes E1 to E4 when a force + Fx, + Fy, + Fz in the positive direction of each coordinate axis is applied to the weight body is shown in FIG. It looks like a table. In other words, in the table of FIG. 12, "expansion" is replaced with "+" and "compression" is replaced with "-" in the table of FIG. The tensile stress when the forces in the negative direction of each coordinate axis-Fx, -Fy, and -Fz act is the reverse of the +/- relationship in this table.

Of course, as the piezoelectric material layer 105, when a stress extending in the layer direction acts, a negative charge is generated upward and a positive charge is generated downward, and when a stress compressing in the layer direction acts, a positive charge is generated upward and a negative charge is generated downward. It is also possible to use one having a polarization property that generates an electric charge. When a piezoelectric material layer having such a polarization characteristic is used, the +/- relationship is reversed as compared with the case described above. Further, when a bulk type piezoelectric element is used, it is possible to arrange piezoelectric elements having different polarization characteristics in each region, and each localized piezoelectric element P1 to P4 has an arbitrary polarization characteristic. Can be made to have.

In any case, the power generation circuit 500 can extract electric power by rectifying the current generated based on the electric charge 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 E1 to E4 are arranged at unique positions on the upper surface of the bridge portion piezoelectric layer 110. Here, these four upper layer electrodes are grouped into the tip left upper layer electrode E1, the tip right upper electrode E2, the root end left upper electrode E3, and the root end right upper electrode E4 according to the individual arrangement positions. I will call it. Then, the projected image of the upper left upper layer electrode E1 on the tip end portion 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 tip portion of the plate-shaped bridge portion 210 becomes negative. The projected image of the upper right upper layer electrode E2 on the right side of the tip on the upper surface of the second layer 200 of the main power generation extends in the direction parallel to the Y axis, and the X coordinate value near the tip of the plate-shaped bridge 210 becomes positive. The projected image of the upper layer electrode E3 on the left side of the root end 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 root end of the plate-shaped bridge 210 is negative. The projected image of the upper layer electrode E4 on the right side of the root end 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-shaped bridge portion 210. It is 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, when a force in any coordinate axis direction acts on the weight body, a large stress is generated in the Y-axis direction at these four arrangement positions. This is clear from the stress distribution diagrams shown in FIGS. 13 to 15. These stress distribution maps show the results of FEM (finite element method) structural analysis by computer using the actual dimensions described in §1, and the state where the root end of the plate-shaped bridge 210 is fixed. The figure shows the distribution of the stress in the Y-axis direction generated in the piezoelectric material layer 105 when a force in the positive direction of a specific coordinate axis acts on the weight body.

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

FIG. 14 is a stress distribution diagram showing the Y-axis stress generated in the 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. As can be seen by referring to the deformation mode shown in FIG. 9, when the force + Fy acts, the compressive stress in the Y-axis direction acts over almost the entire region of the bridge piezoelectric layer 110. Therefore, also in the stress distribution diagram shown in FIG. 14, it is shown that strong compressive stress is generated over almost the entire region of the bridge piezoelectric layer 110. The unique arrangement of the four upper layer electrodes E1 to E4 corresponds to the position where a remarkable stress is generated even in such a stress distribution map.

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

As described above, looking at the stress distribution diagrams shown in FIGS. 13 to 15, the four upper layer electrodes E1 to E4 shown in FIG. 6 are regions in which stress is concentrated regardless of the direction in which the weight body is displaced. It can be seen that the generated charge can be effectively collected. In addition, referring to these stress distribution maps, the upper end positions in the drawings of the upper layer electrodes E1 and E2 shown in FIG. 6 may extend slightly above the boundary line H (in the positive direction of the Y axis). I understand.

With reference to FIGS. 13 to 15, the stress distribution when the force + Fx, + Fy, + Fz in the positive direction of each coordinate axis acts on the weight body has been described above, but the force −Fx, −Fy in the negative direction of each coordinate axis has been described. The stress distribution when ， -Fz acts is the reverse of the compression / expansion 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 regardless of which coordinate axis direction force is applied to the weight body. It will be done. Further, when a force in any coordinate axis direction is applied, an electric charge having opposite polarity is not generated in the same electrode. That is, in the same electrode, the phenomenon that the charges of opposite polarities cancel each other does not occur. Therefore, the power generation element PGE adopting such a unique electrode arrangement can generate 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 electric power.

In FIG. 16, the tip left side piezoelectric element P1 is composed of a tip left upper electrode E1 and a lower electrode E0 shown in FIG. 6, and a portion of the piezoelectric material layer 105 located below the upper electrode E1. The piezoelectric element on the right side of the tip is shown, and the piezoelectric element P2 on the right side of the tip is composed of the upper right upper electrode E2 and the lower electrode E0 on the right side of the tip and a portion of the piezoelectric material layer 105 located below the upper electrode E2. The localized piezoelectric element is shown.

Similarly, the root end left side piezoelectric element P3 is composed of a root end left upper layer electrode E3 and a lower layer electrode E0 shown in FIG. 6, and a portion of the piezoelectric material layer 105 located below the upper electrode E3. A localized piezoelectric element is shown, and the root end right side piezoelectric element P4 includes a root end right upper layer electrode E4 and a lower layer electrode E0, a portion of the piezoelectric material layer 105 located below the upper electrode E4, and a portion located below the upper electrode E4. The localized piezoelectric element composed of 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 each upper layer electrode.

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

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

After all, in this power generation circuit 500, the positive electrode of the capacitance element Cf is guided from the capacitance element Cf for smoothing and the positive charge generated in each of the upper layer electrodes E1 to E4 to the positive electrode side of the capacitance element Cf. Positive charge rectifying elements D1 (+), D2 (+), D3 (+), D4 (+) whose forward direction is toward the side, and negative charges generated in each upper layer electrode E1 to E4 are capacitance elements Cf. Negative charge rectifying elements D1 (-), D2 (-), D3 (-), D4 (-), D2 (-), D4 (-), D4 (-), D2 (-), D3 (-), D4 ( -), And fulfills the function of smoothing and supplying the electrical energy converted from the vibration energy by the capacitive element Cf.

In this circuit diagram, the load ZL includes the positive charge taken out by the positive charge rectifying elements D1 (+), D2 (+), D3 (+), and D4 (+), and the negative charge rectifying element D1 (-). ), D2 (−), D3 (−), and D4 (−) are supplied with the negative charges taken out. 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 in 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 symmetric structure that is plane symmetric with respect to the YZ plane. If such a symmetrical 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 symmetrical positions. The total amount of electricity is almost equal to that of, and efficient power generation can be expected. Further, there is symmetry between the tip electrode group consisting of the upper layer electrodes E1 and E2 and the root end electrode group consisting of the upper layer electrodes E3 and E4 with respect to the central position in the longitudinal direction of the bridge piezoelectric layer 110. .. 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 layer electrodes E1 to E4 are substantially equal, which is efficient. Power generation can be expected.

<<< §3. Displacement limiting structure and power generator >>>
In the main power generation structure MGS shown in FIG. 1, in order to increase the power generation efficiency, it is preferable that the plate-shaped bridge portion 210 is as thin and long as possible. The first reason is that if a thin and long plate-shaped bridge portion 210 is used, the flexibility is increased and a larger amount of bending is generated. If a large amount of bending occurs in the plate-shaped bridge portion 210, a large amount of bending also occurs in the piezoelectric material layer 105, and the amount of power generation increases. If the width of the plate-shaped bridge portion 210 is narrowed, a merit of causing a large bending can be obtained, but a demerit of reducing the amount of power generation occurs because the area of the piezoelectric material layer 105 is reduced.

The second reason for making the plate-shaped bridge portion 210 thin and long is to obtain an appropriate resonance frequency. As described above, the resonance frequency of the weight body determined based on the unique structure of the main power generation structure MGS preferably matches the vibration frequency in the usage environment of the power generation element (transportation equipment, industrial equipment, etc.), and is practically used. The above is preferably designed 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 within such a range, it is advantageous to make the plate-shaped bridge portion 210 thin and long.

Under such circumstances, when designing the power generation element PGE according to the present invention, it is preferable to make the plate-shaped bridge portion 210 thin and long. However, the thin and long plate-shaped bridge portion 210 is liable to be damaged when an excessive external force is applied. For example, FIG. 8 shows a deformation mode of the main power generation structure MGS when a force + Fx in the positive direction of the X axis acts on the weight body, but an excessive force + Fx (excessive acceleration −αx) is present. When it acts, the piezoelectric layer 110 of the bridge portion and the plate-shaped bridge portion 210 of the lower layer thereof may be excessively deformed and 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-shaped 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-shaped bridge portion and a right wing weight portion located on the right side. For example, in the case of the embodiment shown in FIG. 6, the left wing weight portion 330 is arranged below the left wing piezoelectric layer 130, the right wing weight portion 340 is arranged below the right wing piezoelectric layer 140, and the bridge portion piezoelectric. The plate-shaped 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 some displacement limiting walls are provided on the right side and the left side of the main power generation structure MGS shown in FIG. 6, the displacement of the weight body in the left-right direction can be restricted by the displacement limiting walls. For example, as in the example of FIG. 8, when a force + Fx in the positive direction of the X-axis acts on the weight body, the weight body cannot be displaced beyond the displacement limiting wall on the right side. Similarly, when a force-Fx in the negative X-axis direction acts on the weight body, the weight body cannot be displaced beyond the displacement limiting wall on the left side.

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

After all, in the case of the embodiment shown in FIG. 6, the plate-shaped bridge portion 210 located below the bridge portion piezoelectric layer 110 is surrounded by a "U" -shaped weight body and is protected from the surroundings. Therefore, if some kind of displacement limiting wall is provided on the outside of the main power generation structure MGS, it is possible to limit the excessive displacement of the weight body and avoid damage to the plate-shaped bridge portion 210. Since the plate-shaped bridge portion 210 is surrounded by a "U" -shaped weight body, it does not come into direct contact with the displacement limiting wall.

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

In the power generation element PGE according to the present invention, the root end portion of the plate-shaped bridge portion 210 is fixed to the pedestal 400. For example, in FIG. 1, the pedestal 400 is shown as a mere symbol symbol indicating a fixed portion. Further, in FIGS. 6 to 10, the pedestal 400 is shown as a mere fixed surface. In fact, the pedestal 400 may have any structure as long as it can fix the root end portion of the plate-shaped bridge portion 210 and play a role of suspending the weight body in the air. The embodiment described below is an example in which the annular structure surrounding the main power generation structure MGS is used as the pedestal 400, and the inner wall of the annular structure is used as the displacement limiting wall.

FIG. 17 is a top view showing a power generation element PGE using a rectangular annular structure as a pedestal 400 (actually, only a portion of the power generation element structure excluding the power generation circuit 500 from the power generation element PGE is shown. It is shown, and 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 rectangular structure arranged around the main power generation structure is a pedestal. It is 400. The main power generation structure MGS and the pedestal 400 are joined at the position of the 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 composed of a rectangular rectangular structure having four sets of wall portions, that is, a first wall portion 410, a second wall portion 420, a third wall portion 430, and a fourth wall portion 440. Has been done. Here, the first wall portion 410 is arranged adjacent to the main power generation structure MGS on the negative direction side of the X axis to form a wall surface along a plane parallel to the YZ plane, and the second wall portion 420 is the main. It is arranged adjacent to the power generation structure MGS on the X-axis positive direction side, constitutes a wall surface along a plane parallel to the YZ plane, and the third wall portion 430 is in the Y-axis positive direction with respect to the main power generation structure MGS. It is arranged adjacent to the side and constitutes a wall surface along a plane parallel to the XZ plane, and the fourth wall portion 440 is arranged adjacent to the main power generation structure MGS on the negative direction side of the Y axis and is parallel to the XZ plane. It constitutes a wall surface along a plane. Then, the root end portion of the plate-shaped bridge portion 210 forming 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 magnitude acts on the power generation element PGE having such a structure, the weight body (main power generation third layer 300) becomes this. It comes into contact with the inner surface of the pedestal 400 made of an annular structure, and further displacement is restricted. As shown in the figure, 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. A gap dimension d12 is secured between the two. Similarly, a gap dimension d13 is secured between the upper side surface of the main power generation structure MGS and the inner surface of the third wall portion 430, and the lower side surface of the main power generation structure MGS and the inner surface of the fourth wall portion 440. A gap dimension d14 is secured between them.

Therefore, even if an 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 void dimensions d11 and d12, and the weight body. Even if an external force component in the Y-axis direction acts on the weight, the displacement of the weight body is limited to the range of the void dimensions d13 and d14. Therefore, the degree of bending generated in the plate-shaped bridge portion 210 can be limited, and damage to the plate-shaped bridge portion 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 to 20. FIG. 18 is a normal cross-sectional view showing a cross section of the power generation element PGE shown in FIG. 17 cut along the cutting line 18-18. The main power generation structure MGS is composed of 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 laminated, as described above. On the other hand, the pedestal 400 is also composed of a three-layer structure in which the pedestal first layer 401, the pedestal second layer 402, and the pedestal third layer 403 are laminated.

Here, the main power generation first layer 100 and the pedestal first layer 401 are arranged at exactly the same positions with respect to the Z axis, and the main power generation second layer 200 and the pedestal second layer 402 are also arranged at exactly the same positions with respect to the Z axis. Is located in. 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 exactly 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 (center weight portion 320, left wing weight portion 330, right wing weight portion 340) are suspended from the bottom surface of the pedestal 400.

As shown in the figure, a gap dimension 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. A gap dimension d12 is secured between the two. Therefore, the weight body can be displaced within the range of these gap dimensions d11 and d12 in the X-axis direction, but the displacement beyond the range is limited. In this embodiment, d11 = d12 = 20 μm is set.

FIG. 19 is a side sectional view showing a cross section of the power generation element PGE shown in FIG. 17 cut along the cutting line 19-19, and FIG. 20 is a side sectional view showing the cross section of the power generation element PGE shown in FIG. 17 along the cutting line 20-20. It is a side sectional view which shows the cross section which was cut. In each figure, it is clearly shown that the main power generation structure MGS and the pedestal 400 are composed 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 surface and the first of the left wing weight portion 330 and the right wing weight portion 340. A gap dimension d14 is secured between the four wall portions 440 and the inner surface. Therefore, the weight body can be displaced within the range of these gap dimensions d13 and d14 in the Y-axis direction, but the displacement beyond the range is limited. In this embodiment, d13 = d14 = 15 μm is set.

Here, the reason why the main power generation structure MGS is composed of 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 that the power generation operation described in §2 is performed. Because. That is, the main power generation second layer 200 is a layer for forming the plate-shaped bridge portion 210 having flexibility, and the main power generation first layer 100 is for detecting the bending generated in the plate-shaped bridge portion 210. The layer for forming the piezoelectric element, and the main power generation third layer 300 is a layer for functioning as a weight body for applying an external force to the plate-shaped bridge portion 210.

On the other hand, the pedestal 400 can serve as a fixing member for supporting and fixing the root end portion of the plate-shaped bridge portion 210 and as a displacement limiting wall for limiting excessive displacement of the weight body. Functionally, it is not necessary to dare to make it a three-layer structure because it is sufficient. However, in the examples shown in FIGS. 18 to 20, the reason why the pedestal 400 is composed of the same three-layer structure as the main power generation structure MGS is mainly for the convenience of the manufacturing process.

That is, in the case of the embodiment shown in FIG. 18, the pedestal 400 is composed of a laminated structure in which the pedestal first layer 401, the pedestal second layer 402, and the pedestal third layer 403 are laminated in this 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-shaped 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-shaped bridge portion 210. Further, the pedestal third layer 403 is a component that 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 thereof 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 can be formed. It can be composed of the same material layer, and 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 composed of three layers in which the material first layer 1001, the material second layer 1002, and the material third layer 1003 are laminated in this order from the top. The broken line in the figure shows the part that should be the pedestal 400.

In FIG. 21, the material first layer 1001 is a layer intended to form the main power generation first layer 100, and conductive layers serving as electrodes are formed on both 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 composed of, for example, a silicon substrate suitable for forming the plate-shaped 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 made of, for example, a metal substrate such as SUS.

By performing necessary processing (for example, etching processing) on each layer of such a laminated material block 1000, the main power generation structure MGS shown in FIGS. 18 to 20 and the pedestal 400 are simultaneously configured. be able to. Therefore, the manufacturing process can be simplified and mass production can be achieved, and the manufacturing 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 housed in the pedestal 400 made of the square annular structure, the horizontal component of the acceleration exceeding a predetermined size (the component parallel to the XY plane). Is effective, it is possible to limit the displacement of the weight body. Further, an example 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 acts.

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 housed in the device housing 600. In the present application, the power generation element PGE including the device housing 600 is referred to as a “power generation device” for convenience. I will call it. That is, the "power generation device" referred to here is the power generation element PGE (element having the main power generation structure MGS, the pedestal 400, and the power generation circuit 500) and the device housing 600 accommodating the power generation element PGE. And, it will be a device equipped with.

As shown in the figure, the pedestal 400 of the power generation element PGE is fixed to the device housing 600, and when an external force that vibrates the device housing 600 acts, the weight body 300 (main power generation third layer) of the power generation element PGE becomes. , The plate-shaped 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 arranged so as to surround the base substrate 610 for supporting and fixing the power generation element PGE from below, the upper lid substrate 620 that covers the upper part of the power generation element PGE, and the power generation element PGE. It has a side wall plate 630 that connects the base substrate 610 and the upper lid substrate 620. The bottom surface of the pedestal 400 (each wall portion 410 to 440) of the power generation element PGE is located below the bottom surface of the weight body (main power generation third layer 300: 320, 330, 340) of the power generation element PGE, and is a pedestal. The bottom surface of 400 (each wall portion 410 to 440) is fixed to the upper 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). Further, 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 d16 between the lower surface of the upper lid substrate 620 and the upper surface of the main power generation first layer 100. A gap 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 comes into contact with the upper surface of the base substrate 610 or the lower surface of the upper lid substrate 620. , Further displacement is restricted. Thus, according to the power generation device shown in FIG. 22, in the XYZ three-dimensional coordinate system, the displacement of the weight body is displaced even when an excessive acceleration directed in any of the X-axis, Y-axis, and Z-axis directions acts. It becomes possible to limit and prevent damage to the plate-shaped bridge portion 210.

FIG. 23 is a side sectional view of the power generation device according to a modified example in which the roles of the weight body and the pedestal are reversed in the power generation device shown in FIG. The power generation device shown in FIG. 23 is also a device including a power generation element PGE'and a device housing 600 accommodating the power generation element PGE', and the portion of the device housing 600 is completely the same as the device shown in FIG. It is the same. However, the power generation element PGE'shown in FIG. 23 has a slightly different structure from the power generation element PGE shown in FIG. 22.

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 pedestal 400'(410', 420'). , 430', 440') are suspended in the air. Therefore, when an external force that vibrates the device housing 600 acts, the pedestal 400'of the power generation element PGE vibrates in the device housing 600 due to the bending of the plate-shaped 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 base substrate 610 for supporting and fixing the power generation element PGE'from below, the upper lid substrate 620 covering the upper part of the power generation element PGE', and the power generation element PGE'. It has a side wall plate 630 that connects the base substrate 610 and the upper lid substrate 620. The bottom surface of the pedestal 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'. It is located above the bottom surface, and the bottom surface of the main power generation third layer 300'(320', 330', 340') is fixed to the upper surface of the base substrate 610.

As a result, a lower gap portion having a gap dimension d17 is formed between the upper surface of the base substrate 610 and the bottom surface of the pedestal 400'(410', 420', 430', 440'). Further, 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. Contact and further displacement is restricted. Thus, also in the case of the power generation device shown in FIG. 23, the displacement of the weight body is limited even if an excessive acceleration in any of the X-axis, Y-axis, and Z-axis directions acts in the XYZ three-dimensional coordinate system. This makes it possible to prevent damage to the plate-shaped bridge portion 210. As described above, specific dimensional values have been illustrated for the gap dimensions d11 to d18, but of course, the optimum values of the gap dimensions d11 to d18 depend on the dimensional values d1 to d10 of each part shown in FIGS. 6 and 7. It should be determined.

Comparing the operating principles of the power generation device shown in FIG. 22 and the power generation device shown in FIG. 23, in the former case, the main power generation third layer 300 (320, 330, 340) is suspended in the device housing 600. It functions as a weight body in a state, and the vibration energy of this weight body is converted into electrical energy, whereas in the latter case, the pedestal 400'(410', 420', 430', 440') functions as a weight body suspended in the device housing 600, and the vibration energy of the weight body is converted into electrical energy. In the case of the power generation device shown in FIG. 23, in principle, the member 300'should be called a pedestal and the member 400'should be called a weight body. The member 300'is called a weight body, and the member 400' is called a pedestal.

As a general rule, the pedestals 400, 400'surrounding the outside of the main power generation third layer 300, 300' are more likely to form a structure having a larger mass than the third layer 300, 300'. For example, in the example shown in FIG. 17, if the wall thickness of the first wall portion 410, the second wall portion 420, the third wall portion 430, and the fourth wall portion 440 is increased, the mass of the pedestal 400 can be increased. It's easy. If such a pedestal having a large mass is used as a weight body, a larger amount of power generation can be secured. Therefore, as a general theory, the structure shown in FIG. 23 is preferable to the structure shown in FIG. 22 in order to secure the amount of power generation. Of course, even when the structure shown in FIG. 23 is adopted, the displacement of the pedestal 400'in each coordinate axis direction is limited, so that the effect of preventing the plate-shaped bridge portion 210 from being damaged can be obtained.

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

<4-1. First Deformation Example A: Deformation Example 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 composed of a three-layer structure in which 300 are laminated. The planar shapes of these three layers are shown in FIGS. 2 to 4, respectively.

Here, as can be seen by comparing FIGS. 2 and 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 region 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 bending together with the main power generation second layer 200 and to generate power based on this bending. Therefore, in principle, the main power generation first layer 100 (piezoelectric element) is used. It suffices that the layer 100 (piezoelectric element) is formed on the upper surface of the plate-shaped bridge portion 210 where bending occurs. The main power generation first layer 100 shown in FIG. 2 is composed of four parts: a bridge portion piezoelectric layer 110, a central piezoelectric layer 120, a left wing piezoelectric layer 130, and a right wing piezoelectric layer 140. In principle, the bridge portion Only the piezoelectric layer 110 may be provided, and more specifically, it may be formed only in the region of the bridge portion piezoelectric layer 110 where the upper layer electrodes E1 to E4 are formed.

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 do not necessarily have to be the same, and the main power generation first layer 100 is a plate-shaped bridge of the main power generation second layer 200. It suffices 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 FIGS. 3 and 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-shaped bridge portion 210. ing. That is, the planar shapes of the central plate-shaped portion 220, the left wing plate-shaped portion 230, and the right wing plate-shaped portion 240 constituting each portion of the main power generation second layer 200 shown in FIG. 3 are shown in FIG. 4, respectively. It has the same planar shape as the central weight portion 320, the left wing weight portion 330, and the right wing weight portion 340 constituting each part of the main power generation third layer 300. The difference between the two in the plan shape is that the portion corresponding to the plate-shaped bridge portion 210 of the main power generation second layer 200 shown in FIG. 3 is a hollow portion in the main power generation third layer 300 shown in FIG. Only the point that is 310.

In this way, 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 shapes of the planar shapes of the three layers are 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 do not necessarily have to be substantially 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. Similar to the main power generation structure MGS shown in FIG. 1, the main power generation structure MGSa is composed of a three-layer structure consisting of a main power generation first layer 100a, a main power generation second layer 200a, and a main power generation third layer 300a. However, the planar shape of each layer is different. In this 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 these and the planar shape of the main power generation third layer 300a are significantly different. 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 behind the main power generation first layer 100a and does not appear in the figure. Each component of the main power generation second layer 200a arranged so as to overlap is shown. As is clear from the figure, the outer peripheral portion of the main power generation third layer 300a projects largely outward from the outer peripheral portion 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 projects larger outward than the central piezoelectric layer 120a and the central plate-shaped portion 220a. Further, the left wing weight portion 330a has a structure that projects larger than the left wing piezoelectric layer 130a and the left wing plate-shaped portion 230a, and the right wing weight portion 340a has a structure that is larger than the right wing piezoelectric layer 140a and the right wing plate-shaped portion 240a. It has a structure that overhangs greatly to the outside.

Since the main power generation structure MGSa having such a structure also has a plane-symmetrical 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-shaped 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.

In this way, the outer peripheral portion of the main power generation third layer 300a (central weight portion 320a, left wing weight portion 330a, right wing weight portion 340a) that functions as a weight body is covered with the main power generation first layer 100a and the main power generation first layer. By adopting a structure that projects greatly outward from the outer peripheral portion of the two layers 200a, it is possible to improve the function of protecting the main power generation first layer 100a and the main power generation second layer 200a when excessive vibration is applied. ..

That is, in the case of the main power generation structure MGS shown in FIG. 17, since the plate-shaped bridge portion 210, which is most likely to be damaged, is surrounded by the “U” -shaped structure, an external force that causes excessive displacement is generated. Even if it is added, the plate-shaped bridge portion 210 itself does not come into contact with the pedestal 400. However, as is clear from FIG. 18, since 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, an external force that causes excessive displacement is generated. Is added, the outer peripheral portion of each of these layers comes into contact with the inner surface of the pedestal 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 they come into contact with 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 is adopted in which the outer peripheral portion of the thick main power generation third layer 300a projects outward, an external force that causes excessive displacement is adopted. Is added, the outer peripheral portion of the main power generation third layer 300a comes into contact with the inner surface of the pedestal 400, and further displacement is restricted. Therefore, it is possible to prevent the outer peripheral surfaces of the main power generation first layer 100a and the main power generation second layer 200a having a small thickness from coming into contact with the inner surface of the pedestal 400, and it is possible to prevent damage to the outer peripheral portion.

In the main power generation structure MGSa shown in FIG. 24, the main power generation third layer 300a is projected in all directions in the vertical and horizontal directions in the figure, but in order to obtain the above protection effect, it is not necessarily projected in all directions. You don't have to let it. That is, with respect to the main power generation third layer 300a that functions as a weight body, a part of the outer peripheral portion thereof comes into contact with the inner surface of the pedestal 400 to limit the displacement in the vertical direction in the figure and the displacement in the horizontal direction in the figure. It suffices 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 body support portions (220a, 230a, 240a). The end of the main power generation third layer 300a in the negative direction of the X axis protrudes in the negative direction of the X axis from the end of the weight body support portion (220a, 230a, 240a) in the negative direction of the X axis. The Y-axis positive end of the three layers 300a protrudes in the Y-axis positive direction from the Y-axis positive ends of the weight body support portions (220a, 230a, 240a), and the main power generation third layer 300a The end portion in the negative direction of the Y-axis may protrude in the negative direction of the Y-axis from the end portion in the negative direction of the Y-axis of the weight body support portions (220a, 230a, 240a).

<4-2. Second modification B: Separation structure of weight body>
In the basic embodiments described so far, as shown in FIG. 4, the main power generation third layer 300 that functions as a weight body is composed of a central weight portion 320, a left wing weight portion 330, and a right wing weight portion 340. It was composed of two parts (the same applies to the first modification A shown in FIG. 24). 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 axis (Y axis) of the plate-shaped bridge portion 210 are provided. If the main power generation structure MGS having the structure is used, the required effects can be obtained. In other words, in carrying out the present invention, the central weight portion 320 connecting the left wing weight portion 330 and the right wing weight portion 340 is not indispensable.

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

The difference between the main power generation structure MGSa shown in FIG. 24 and the main power generation structure MGSb shown in FIG. 25 is only the structural portion 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 portion 320a, a left wing weight portion 330a, and a right wing weight portion 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 portion 330b and a right wing weight portion 340b. The central weight portion connecting the two is not provided.

The left wing weight portion 330b is joined to the lower surface of the left wing plate-shaped portion 230b (weight body support portion), and the right wing weight portion 340b is joined to the lower surface of the right wing plate-shaped portion 240b (weight body support portion). The displacement generated in the weight body is transmitted to the tip of the plate-shaped 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, the left wing weight portion 330b and the right wing weight portion 340b, but the structure is plane-symmetric with respect to the YZ plane. Therefore, the center of gravity Gb of the weight body is located on the YZ plane below the plate-shaped bridge portion 210b. Therefore, there is no change in the point that the weight body vibrates stably in each coordinate axis direction.

Further, the main power generation structure MGSb shown in FIG. 25, like the main power generation structure MGSa shown in FIG. 24, has a main power generation third as compared with the outer peripheral portions 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 has a structure that projects outward, it is possible to prevent the outer peripheral surfaces of the small main power generation first layer 100b and the main power generation second layer 200b from coming into contact with the inner surface of the pedestal 400. It is also possible to obtain the effect of preventing damage to the outer peripheral portion.

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

Therefore, even if an external force that causes excessive displacement in the vertical direction in the figure or the horizontal direction in the figure is applied to the weight body, the outer peripheral portion of the main power generation third layer 300b (weight body) is always a pedestal. It contacts the inner surface of the 400 and further displacement is restricted. Therefore, 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 coming into contact with the inner surface of the pedestal 400, and it is possible to prevent damage to the outer peripheral portion.

<4-3. Third modification C: Connection angle of plate-shaped bridge>
FIG. 26 is a top view showing the connection angles of both ends of the plate-shaped 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-shaped bridge portion 210, a central plate-shaped portion 220, a left wing plate-shaped portion 230, and a right wing plate-shaped portion 240.

Here, the plate-shaped bridge portion 210 is a central portion that causes bending that is directly related to the power generation operation, and has flexibility that extends along the first longitudinal axis L1 (Y axis in the explanation so far). It is a beam-like structure. On the other hand, the central plate-shaped portion 220 is a structure extending along a second longitudinal axis L2 (X'axis in the explanation so far) orthogonal to the first longitudinal axis L1 and is a first structure. It is arranged at a position symmetrical with respect to the longitudinal axis L1 of. The tip of the plate-shaped bridge portion 210 is connected to the central side of the central plate-shaped portion 220 at the tip point T, and both form a T-shaped structure.

Further, the left wing plate-shaped portion 230 is connected to the left side of the central plate-shaped portion 220, and the right wing plate-shaped portion 240 is connected to the right side. It constitutes a flat plate-like structure in the shape of. The boundary line H'in the figure corresponds to the boundary line for separating the regions of each of these parts from each other.

In such a main power generation second layer 200, paying attention to the connection state with respect to the central plate-shaped portion 220 at the tip portion (near the tip point T) of the plate-shaped bridge portion 210, the connection angles θ1 and θ2 shown in the figure are , Both are 90 °. Here, the connection angle θ1 is the angle formed by the left side of the plate-shaped bridge portion 210 and the boundary line H', and the connection angle θ2 is the angle formed by the right side of the plate-shaped bridge portion 210 and the boundary line H'. Is. In this way, 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-shaped bridge portion 210 is the first. This is because the longitudinal axis L1 of the above is arranged as the central axis, and the rectangular central plate-shaped portion 220 is arranged with the second longitudinal axis L2 as the central axis.

Similarly, paying attention to the connection state with respect to the pedestal 400 at the root end portion (near the origin O) of the plate-shaped bridge portion 210, the connection angles θ3 and θ4 shown in the figure are both 90 °. Here, the connection angle θ3 is the angle formed by the left side of the plate-shaped bridge portion 210 and the inner surface of the pedestal 400, and the connection angle θ4 is the angle between the right side of the plate-shaped bridge portion 210 and the inner surface of the pedestal 400. It is a suspended angle. In this way, 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-shaped 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 the 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-shaped bridge portion 210c, a central plate-shaped portion 220c, a left wing plate-shaped portion 230c, and a right wing plate-shaped portion 240c. However, the plane shape of these individual parts is not a rectangle but an irregular figure. Further, the plate-shaped bridge portion 210c is a member extending in a direction along the longitudinal axis L1', but the longitudinal axis L1'is not orthogonal to the inner surface of the pedestal 400. Therefore, the connection angles θ1 and θ2 for the tip of the plate-shaped bridge portion 210c and the connection angles θ3 and θ4 for the root end are not 90 °.

As described above, even when the power generation element according to the present invention is formed by using the main power generation second layer 200c having an irregular shape according to the third modification C shown in FIG. 27, power generation can be performed without any trouble. 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-shaped portion 230c and a right wing weight portion 340c joined to the lower surface of the right wing plate-shaped portion 240c is provided, the weight thereof. Since the plate-shaped bridge portion 210c is bent due to the vibration of the weight body, power can be generated by the piezoelectric element provided on the upper surface thereof.

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

However, in practice, as shown in the example shown in FIG. 26, each part of the main power generation second layer 200 is composed of members having a rectangular plane, and the plate-shaped bridge part 210 is orthogonal to the inner surface of the pedestal 400. The first longitudinal axis L1 is arranged so as to be the central axis, and the central plate-shaped portion 220 is arranged so that the second longitudinal axis L2 orthogonal to the first longitudinal axis L1 is the central axis. It is preferable that the plate-shaped bridge portion 210 and the central plate-shaped portion 220 form a T-shape at right angles to each other. With such a configuration, the connection angles θ1 to θ4 are all 90 °, and stress can be concentrated on the tip and root ends of the plate-shaped bridge portion 210 (see FIGS. 13 to 15). , It is possible to efficiently generate electric charges on the four upper layer electrodes E1 to E4 arranged at the positions shown in FIG.

<4-4. Fourth variant D: Independent main power generation component>
Since the power generation element PGE shown in FIG. 18 is composed of both the main power generation structure MGS portion and the pedestal 400 portion by a three-layer structure, a single laminated material block 1000 as shown in FIG. 21 is prepared. As already mentioned, it is suitable for mass production because it can be manufactured by subjecting it to processing such as etching.

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

In particular, in consideration of mass productivity, at 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 electrode E0 is formed on the upper surface thereof. A material first layer 1001 is formed by forming a piezoelectric material layer on the upper surface and further forming a metal layer to be the upper layer electrodes E1 to E4 on the upper surface thereof, and this is a material third layer 1003 made of a metal substrate. It is preferable to join to the upper surface of the.

However, at present, the processing process for forming a piezoelectric element on a silicon substrate requires advanced equipment and requires a great deal of cost. 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 of manufacturing the power generation element PGE shown in FIG. 18 can be efficiently performed by using the laminated material block 1000 shown in FIG. 21, the procurement cost of the laminated material block 1000 is relatively high. I have no choice but to become.

In fact, the piezoelectric element that is directly involved in the power generation function of the power generation element PGE is only the portion formed on the upper surface of the plate-shaped bridge portion 210, and it is not necessary to form the piezoelectric element in other regions. In particular, the piezoelectric element formed on the pedestal 400 is useless, and it is not necessary to use a silicon substrate for the pedestal 400 in the first place. Therefore, here, a modified example capable of significantly reducing the planar size of the silicon substrate and the piezoelectric element formed on the upper surface thereof and reducing 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. 28 (b) is a top view thereof. It is a regular cross-sectional view cut along the 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, exactly 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 excluding the weight body 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 longitudinal axis L1 and the first member 710d extending along the second longitudinal axis L2. It is composed of a second member 720d and a third member 730d extending along the third longitudinal axis L3. Here, the first longitudinal axis L1, the second longitudinal axis L2, and the third longitudinal axis L3 are all included in the same common plane, and the first longitudinal axis L1 and the second longitudinal axis L1 are included. It is orthogonal to the longitudinal axis L2, 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 normal cross-sectional view of FIG. 28 (b), only the cross-sectional portion obtained by cutting the first member 710d along the cutting line bb is shown. As shown in the figure, in the first member 710d, for example, a lower layer electrode E0 made of metal is formed on the upper surface of a plate-shaped bridge portion 712d made of silicon, a bridge portion piezoelectric layer 711d is formed on the upper surface thereof, and the upper surface thereof is further formed. It has a structure in which upper layer electrodes E1 to E4 (only E1 and E2 located on the cut surface appear in the figure) are formed at predetermined locations, and the layer structure and the thickness dimension of each layer are shown in FIG. It is the same as the example shown. Therefore, in the case of this embodiment, the thickness dimension d19 of the first member 710d (the dimension from the lower surface of the plate-shaped 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 not shown, the second member 720d and the third member 730d also have a similar layer structure. That is, the second member 720d has a structure in which, for example, a lower layer electrode E0 made of metal is formed on the upper surface of a central plate-shaped portion 722d made of silicon, and a central piezoelectric layer 721d is formed on the upper surface thereof. In the 730d, for example, a lower layer electrode E0 made of metal is formed on the upper surface of a pedestal connecting portion 732d made of silicon, a connecting portion piezoelectric layer 731d is formed on the upper surface thereof, and a bonding pad B (not shown) is further formed at a predetermined position on the upper surface thereof. In the example of, it has a structure in which (provided at five places) is formed.

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 case of 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. Wiring from the power generation circuit 500 is made to each bonding pad B.

Also in this fourth modification D, the four upper layer electrodes E1 to E4 are located at 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. It is formed and all are arranged in the region where stress is concentrated. Looking at the stress distribution diagrams shown in FIGS. 13 to 15, the upper end positions in the drawings 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 can be seen that it may extend upward in the figure (region of the second member 720d). Similarly, the lower end position in the drawings of the upper layer electrodes E3 and E4 shown in FIG. 28 extends slightly downward in the drawing (region of the third member 730d) beyond the boundary line between the first member 710d and the third member 730d. I understand that it is okay to have it.

On the other hand, FIG. 29 is a top view showing the weight body 300d used in the fourth modification D. Similar to the weight body 300 (third layer of main power generation) shown in FIG. 4, the weight body 300d is made of a material such as metal, glass, or ceramics, and has a central weight portion 320d, a left wing weight portion 330d, and the like. It is a "U" -shaped component having three portions called a right wing weight portion 340d, and has a cavity portion 310d. Of course, the thickness of the weight body 300d is set to such a size that sufficient mass for causing the first member 710d shown in FIG. 28 to be bent can be obtained. In the case of 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, and the depth dimension thereof is the second member 720d. It is set to be larger than the thickness dimension.

FIG. 30 is a top view showing the pedestal 400d used in the fourth modification D. 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, while the pedestal 400 was composed of a three-layer structure as shown in FIG. 18 (having a layer structure similar to that of the main power generation structure MGS), the pedestal 400d shown in FIG. 30 has such a 3 layer structure. It does not have to have a layered structure, and may be, for example, a single-layered structure made of a material such as metal. This is because, in the case of the fourth modification D shown here, the pedestal 400d is manufactured by a process completely separate from the main power generation component 700d shown in FIG. 28.

In the case of the illustrated embodiment, a rectangular fitting groove 445d is formed in 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, and the depth dimension thereof is 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 generation element PGEd according to the fourth modification D (however, only the portion of the power generation element structure excluding the power generation circuit 500 is shown, and the power generation circuit 500 is shown. Not shown). The power generation element PGEd is configured by attaching the main power generation component 700d shown in FIG. 28 and the weight body 300d shown in FIG. 29 to the pedestal 400d shown in FIG.

Specifically, the second member 720d of the main power generation component 700d shown in FIG. 28 is placed in the fitting groove 325d provided in the central weight portion 320d of the "U" -shaped weight body 300d shown in FIG. 29. It is fitted and the lower surface of the second member 720d is adhered 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 pedestal 400d shown in FIG. 30, and the lower surface of the third member 730d is fitted into the fitting groove 445d. Adhere to the bottom. Then, the power generation element PGEd shown in FIG. 31 is completed (actually, it is necessary to wire between the power generation circuit 500 and the bonding pad B (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 housed inside the rectangular pedestal 400d, and the point that the main power generation structure MGSd is composed 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 shown by the reference numerals in parentheses in FIG. 28, the main power generation second layer constituting the main power generation structure MGSd further has a pedestal connection portion 732d connected to the root end portion of the plate-shaped bridge portion 712d. There is. The pedestal connection portion 732d uses a third longitudinal axis L3 (axis parallel to the X axis in the basic embodiment) that intersects 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-shaped portion 722d (second member 720d) and adhering the lower surface thereof is formed on the upper surface of the weight body 300d at a predetermined position. , The central plate-shaped 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 pedestal connecting portion 732d (third member 730d) and adhering the lower surface thereof is formed on the upper surface of the predetermined portion of the pedestal 400d. , The pedestal connecting portion 732d is fixed in a state of being fitted in the fitting groove 445d.

As shown in FIG. 31, in the case of 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 the fitting groove. Fit within 325d with a margin. On the other hand, the planar shape of the fitting groove 445d is designed to match the planar shape of the third member 730d, and the third member 730d is fitted in the fitting groove 445d exactly. Of course, the relationship between the fitting grooves 325d and 445d and the members 720d and 730d to be fitted therein does not necessarily have to be the same as in this embodiment. In either case, it may be designed so that it fits in the groove with a margin, or it may be designed so that it fits snugly.

On the other hand, the relationship between the depth of each fitting groove 325d, 445d and the thickness of the members 720d, 730d to be fitted therein is such that the former dimension is larger than the latter dimension, that is, fitting. It is preferable to design the groove so that it is deeper than the thickness of the member. This is a consideration for protecting the main power generation component 700d from damage. Since the main power generation component 700d is a component including, for example, a silicon substrate, a piezoelectric element layer, and electrodes, it is a component that is more easily damaged than 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 comes into 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. Located below the upper surface of 320d (in the back direction of the figure), the second member 720d is completely embedded inside the weight body 300d 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 of the third member 730d (the upper surface including the bonding pad B) is the first. Located below the upper surface of the 4 wall portion 440d (in the back direction of the figure), the third member 730d is completely embedded inside the pedestal 400d and is protected from contact with external members. There is. 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 if an excessive acceleration is applied and each part is greatly displaced.

The manufacturing process of the power generation element PGEd according to the fourth modification D is different from the manufacturing process of the power generation element PGE according to the basic embodiments shown in FIGS. 17 and 18, and the steps of assembling the parts by adhering them to each other. However, even when the layer connected to the plate-shaped bridge portion 712d is made of silicon, the silicon layer and the piezoelectric element on the upper surface thereof need only be formed in the portion of the main power generation component 700d shown in FIG. 28. Therefore, the planar size of the silicon substrate and the piezoelectric element formed on the upper surface thereof can be significantly reduced, and the manufacturing cost can be reduced.

Further, in the case of the fourth modification D, as shown in FIG. 28, the first member 710d (plate-shaped bridge portion 712d) arranged along the first longitudinal axis L1 and the second longitudinal axis Since the second member 720d (central plate-shaped portion 722d) arranged along L2 and the third member 730d (pedestal connecting portion 732d) arranged along the third longitudinal axis L3 are orthogonal to each other, The 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-shaped bridge portion 712d, and the power generation efficiency can be improved.

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

For example, in the basic embodiments and modifications described so far, the main power generation structure MGS is composed of a three-layer structure, but in carrying out the present invention, it is not always necessary to use the 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 to integrally form the plate-shaped bridge portion and the weight body with a silicon substrate or the like. Of course, the plate-shaped 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 arranged below the plate-shaped bridge portion, but the weight body connected from below to above the plate-shaped 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 vibrational energy into electrical energy, and as shown in FIG. 1, extends along a first longitudinal axis Y to increase flexibility. A plate-shaped bridge portion 210, a pedestal 400 that supports and fixes the root end portion of the plate-shaped bridge portion 210, a weight body 300 directly or indirectly connected to the tip portion of the plate-shaped bridge portion 210, and 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 for rectifying a current generated based on the charge generated in the piezoelectric element 100 and extracting electric power are provided. 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-shaped bridge portion 210 and a right wing weight portion 340 located on the right side with respect to the longitudinal axis Y of the plate-shaped bridge portion 210. And, it suffices to have.

However, in order to generate more efficient power generation, the weight body support portions 220, 230, 240 are connected to the tip portion of the plate-shaped 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-shaped bridge portion 210.

In particular, in the basic embodiment shown in FIG. 1, as a weight body support portion, a central plate-shaped portion 220 extending along a second longitudinal axis X'orthogonal to the first longitudinal axis Y is provided. The tip of the plate-shaped bridge portion 210 is connected to the vicinity of the center of the central plate-shaped portion 220 so that the plate-shaped bridge portion 210 and the central plate-shaped portion 220 form a T-shaped structure. A structure is adopted in which 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 body support portion extends along the second longitudinal axis X ′ orthogonal to the first longitudinal axis Y, and the vicinity of the center is located. A central plate-shaped portion 220 connected to the tip of the plate-shaped bridge portion 210, a left wing plate-shaped portion 230 extending from the left side of the central plate-shaped portion 220 to the left side of the plate-shaped bridge portion 210, and a central plate-shaped portion 210. It is composed of a right wing plate-shaped portion 240 extending from the right side of the plate-shaped bridge portion 210 to the right side of the plate-shaped bridge portion 210, the left wing weight portion 330 is connected to the lower surface of the left wing plate-shaped portion 230, and the right wing weight portion 340 is connected to the right wing. A structure that connects to the lower surface of the plate-shaped 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-shaped portion 220. I have to.

By adopting such a configuration, it is possible to realize a structure in which the circumference of the plate-shaped bridge portion 210 is covered by the weight body 300 in a "U" shape, and the center of gravity G of the weight body 300 is covered by the plate-shaped bridge portion. It can be placed in place below the 210. Therefore, the plate-shaped bridge portion 210 can be efficiently bent based on the displacement of the weight body 300. Further, 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 is applied to the weight body 300. , It is possible to prevent the plate-shaped bridge portion 210 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 periphery of the main power generation structure MGS having the plate-shaped 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 made of the annular structure, and the displacement is further increased. Can be restricted.

As shown in FIG. 26, when the plate-shaped bridge portion 210 and the central plate-shaped portion 220 are orthogonal to each other to form a T-shaped structure, a force in each coordinate axis direction acts 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 tip portion of the plate-shaped bridge portion 210 and on the left and right sides of the root end portion.

Therefore, as the piezoelectric element, the tip left side piezoelectric element P1 (piezoelectric element formed in the region of the upper layer electrode E1) arranged on the left side near the tip of the plate-shaped bridge portion 210 and the tip of the plate-shaped bridge portion 210. The tip right side piezoelectric element P2 (piezoelectric element formed in the region of the upper electrode E2) arranged on the right side near the portion and the root end left side piezoelectric element arranged on the left side near the root end portion of the plate-shaped bridge portion 210. The element P3 (piezoelectric element formed in the region of the upper electrode E3) and the right side piezoelectric element P4 (formed in the region of the upper electrode E4) arranged on the right side near the root end of the plate-shaped bridge portion 210. If a piezoelectric element) is provided, efficient power generation becomes possible.

Further, as shown in FIG. 1, the specific structure of the piezoelectric element is formed into a layered lower layer electrode E0 formed on the surface of the plate-shaped bridge portion 210 and a layered layer on the surface of the lower layer electrode E0. A laminated structure having a piezoelectric material layer 105 and an upper layer electrode group composed of a plurality of upper layer electrodes E1 to E4 locally formed on the surface of the piezoelectric material layer 105 may be adopted. Here, as the piezoelectric material layer 105, 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 may be used.

In the case of the embodiment shown in FIG. 1, the piezoelectric element (main power generation first layer 100) is formed on the upper surface of the plate-shaped bridge portion 210 (main power generation second layer 200), but the piezoelectric element is not necessarily a plate. It is not necessary to form the bridge portion 210 on the upper surface, and it is possible to form the bridge portion 210 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-shaped bridge portion 210 generates stress not only on the upper surface but also on the side surface and the lower surface, power can be generated by the piezoelectric element formed on the side surface and the lower surface.

In short, the piezoelectric element may be formed on the surface of the plate-shaped bridge portion 210 regardless of the upper surface, the side surface, or 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-shaped bridge portion 210, the piezoelectric material layer 105 is formed over the entire surface of the lower layer electrode E0, and a predetermined portion of the surface of the piezoelectric material layer 105 ( If a plurality of upper layer electrodes are locally formed not only on the upper surface of the plate-shaped bridge portion 210 but also on the side surfaces), the piezoelectric element is formed not only on the upper surface but also on the side surface of the plate-shaped bridge portion 210. Will be formed. In this case, not only the piezoelectric element formed on the upper surface but also the piezoelectric element formed on the side surface enables power generation.

However, in order to form the piezoelectric element not only on the upper surface of the plate-shaped bridge portion 210 but also on the side surface and the lower surface, a complicated process is required, so that the manufacturing cost has to rise. Therefore, in practical use, it is preferable to adopt a structure in which the piezoelectric element is provided on the upper surface of the plate-shaped bridge portion 210 to reduce the cost, as shown in the basic embodiments described above and the modified examples thereof. In particular, when the laminated material block 1000 as shown in FIG. 21 is prepared and a mass production process is adopted in which a predetermined processing process is applied to the laminated material block 1000, the piezoelectric element must be formed on the upper surface of the plate-shaped bridge portion 210.

As in the example shown in FIG. 22, when the power generation element PGE is housed in the device housing 600 to form the power generation device, the pedestal 400 of the power generation element PGE is fixed to the device housing 600 and the device housing 600. When an external force that vibrates the body 600 is applied, the weight body 300 of the power generation element PGE vibrates in the apparatus housing 600 due to the bending of the plate-shaped bridge portion 210, and is taken out from the power generation circuit 500 in response to the vibration. The configuration may be adopted to output the generated power.

Alternatively, as in the example shown in FIG. 23, it is possible to adopt a configuration in which the roles of the weight body and the pedestal are reversed. In this case, a power generation element PGE ′ whose bottom surface of the weight body 300 ′ is located below the bottom surface of the pedestal 400 ′ is prepared, and the weight body 300 ′ of this power generation element PGE ′ is attached to the device housing 600. When an external force that fixes and vibrates the device housing 600 is applied, the pedestal 400'of the power generation element PGE'vibrates in the device housing 600 due to the bending of the plate-shaped bridge portion 210, and responds to the vibration. A configuration may be adopted in which the electric power extracted from the power generation circuit 500 is output.

Of course, the power generation element PGE can also be configured by a method of assembling some individual parts as in the embodiment shown in FIGS. 28 to 31. In the case of the main power generation component 700d shown in FIG. 28, the pedestal connecting portion 732d extending along the longitudinal axis L3 orthogonal to the longitudinal axis L1 at the root end of the plate-shaped bridge portion 712d extending along the longitudinal axis L1. Is connected, and by fixing the pedestal connecting portion 732d to the pedestal 400d, assembly can be performed.

100: Main power generation first layer 105: Piezoelectric material layer 110: Bridge part piezoelectric layer 120: Central piezoelectric layer 130: Left wing piezoelectric layer 140: Right wing piezoelectric layer 200: Main power generation second layer 210, 210a, 210b, 210c: Plate-like Bridge portions 220, 220a, 220b, 220c: Central plate-shaped portion (weight body support portion)
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 part 320, 320a, 320d: Central weight part (weight body)
325d: Fitting grooves 330, 330a, 330b, 330d: Left wing weight portion (weight body)
340, 340a, 340b, 340d: Right wing weight part (weight body)
400, 400d: Pedestal 401: Pedestal 1st layer 402: Pedestal 2nd layer 403: Pedestal 3rd layer 410, 410d: 1st wall portion 420, 420d: 2nd wall portion 430, 430d: 3rd wall portion 440, 440d : Fourth wall portion 445d: Fitting groove 500: Power generation circuit 600: Equipment housing 610: Base substrate 620: Top lid substrate 630: Side wall plate 700d: Main power generation component 710d: First member 711d: Bridge portion piezoelectric layer 712d: Plate Bridge part 720d: Second member 721d: Central piezoelectric layer 722d: Central plate-shaped part 730d: Third member 731d: Connection part Piezoelectric layer 732d: Pedestal connection part 1000: Laminated material block 1001: Material first layer 1002: Material first 2nd layer 1003: Material 3rd layer B: Bonding pad Cf: Smoothing piezoelectric element (capacitor)
D0 (+) to D4 (+): Positive charge rectifying element (diode)
D0 (-) to D4 (-): Negative charge rectifying element (diode)
d1 to d10: Actual dimensions of each part d11 to d18: Void size 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 Right upper layer electrode Fx: Force in X-axis direction Fy: Force in Y-axis direction Fz: Force in Z-axis direction G, Ga, Gb: Center of gravity of weight body H, H': Boundary lines L1, L2 of each part 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 (root end) of XYZ three-dimensional coordinate system
P1: Tip left side piezoelectric element P2: Tip right side piezoelectric element P3: Root end left piezoelectric element P4: Root end right piezoelectric element PGE, PGE', PGEd: Power generation element T, T': Tip point (tip)
X: XYZ three-dimensional coordinate system coordinate axis X': axis parallel to the X axis Y: XYZ three-dimensional coordinate system coordinate axis Z: XYZ three-dimensional coordinate system coordinate axis ZL: load of equipment receiving power θ1 to θ4: plate Connection angle of the bridge

Claims (2)

A power generation element that generates electricity by converting vibrational energy into electrical energy, which extends from the root end to the tip along the longitudinal axis and has flexibility in a plate-shaped bridge portion and the root end portion. A main power generation component having a connected pedestal connection portion and a plurality of sets of piezoelectric elements fixed at predetermined positions where expansion and contraction deformation of the plate-shaped bridge portion occurs.
The tip of the plate-shaped bridge is directly or indirectly connected to the weight body.
The pedestal connection is arranged on a predetermined arrangement axis that intersects the longitudinal axis and extends along the arrangement axis.
The plurality of sets of piezoelectric elements include a tip piezoelectric element arranged near the tip of the plate-shaped bridge portion and a root end piezoelectric element arranged near the root end of the plate-shaped bridge portion. And
Each of the piezoelectric elements is formed into a layered lower layer electrode formed on the surface of the plate-shaped bridge portion, a piezoelectric material layer formed layered on the surface of the lower layer electrode, and a layered surface on the surface of the piezoelectric material layer. A material having an upper electrode 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 is used.
When the weight body is displaced in a direction orthogonal to the longitudinal axis and the arrangement axis, a charge of the first polarity is generated in the upper electrode of the tip piezoelectric element, and the root end portion. A power generation element characterized in that an electric charge having a second polarity opposite to that of the first polarity is generated in the upper electrode of the piezoelectric element. In the power generation element according to claim 1,
When the weight body is displaced in the direction of the longitudinal axis, charges of the same polarity are generated in the upper layer electrode of the tip end piezoelectric element and the upper layer electrode of the root end piezoelectric element. A characteristic power generation element.

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