WO2017014003A1 - Power generation device and electric apparatus provided with same - Google Patents

Abstract

A power generation module (10) is provided with: a movable unit (60) that is displaced corresponding to an external force (F); a piezoelectric element (1) that generates power by being deformed corresponding to the displacement of the movable unit (60); a control unit (71) that is configured to limit the displacement of the movable unit (60); and a load switch (31). The load switch (31) is connected in series between the piezoelectric element (1) and output nodes (T1, T2), and is configured to be electrically connected when the displacement quantity of the movable unit (60) reaches a displacement quantity to be limited by the control unit (71).

Description

Power generation device and electric device provided with the same

The present invention relates to a power generation device and an electric device including the power generation device, and more particularly to a power generation device including a piezoelectric element and an electric device including the power generation device.

Conventionally, various technologies related to power generation devices including piezoelectric elements have been proposed. For example, Japanese Unexamined Patent Publication No. 2011-103729 (Patent Document 1) discloses a manual operation device. The manual operation device includes a touch sensor type input unit, a control unit that executes a control operation in accordance with an instruction input to the input unit, a power generation unit configured of a piezoelectric material, and a power supply from the power generation unit. And a power supply unit that supplies power from the charging unit to the control unit. When the touch sensor is used, an input instruction can be detected even after the user relaxes the finger, so that the circuit operation can be started after waiting for the power generation by the restoration of the power generation unit. By setting the start timing of the circuit operation after the restoration of the power generation unit, the operation of the control unit can be started after the charging unit is sufficiently charged, and the operation of the control unit is stabilized.

Also, for example, International Publication No. 2003/25969 (Patent Document 2) discloses a power supply device. The power supply device includes switch means that does not start discharging until it is determined that the power charged in the charging unit has reached a predetermined level of charge. That is, according to this power supply device, the charging unit is supplied with electric power charged to a required amount at a stretch. As a result, even a piezoelectric element with generally small generated power can be applied as a power supply device to an external device that requires relatively large power.

JP 2011-103729 A International Publication No. 2003/25969

The manual operation device disclosed in Patent Document 1 further includes an operation start control unit. The operation start control unit includes a comparator, a voltage dividing resistor, a reference voltage generation circuit, and the like. The operation start control unit outputs a signal (enable signal) indicating whether or not the detected voltage exceeds the reference potential as an operation start command to the power supply unit. When the enable signal becomes H (high) level, the power supply unit converts the power stored in the charging unit into a predetermined voltage and starts power supply.

The power supply device disclosed in Patent Document 2 further includes determination means for controlling the switch means. The determination unit includes a resistor and a capacitor, and determines whether or not the voltage of the charging unit has reached a predetermined level according to the power generation timing of the piezoelectric element.

Thus, in each device disclosed in Patent Documents 1 and 2, the voltage generated by the piezoelectric element (more specifically, the voltage after rectification) is detected. Then, the power supply to the subsequent load is controlled according to the determination result of the magnitude relationship between the detected voltage and a predetermined threshold voltage.

Each element constituting an electric circuit (operation start control unit or determination means) for detecting a voltage generated by the piezoelectric element may include manufacturing variations. Furthermore, the piezoelectric element can also include manufacturing variations. For this reason, the determination result varies due to manufacturing variation of each element, and depending on the apparatus, there is a possibility that the power supply control operation is not appropriately executed. Therefore, in order to ensure the reliability of the device, it is desirable to set a margin in consideration of device manufacturing variations when setting the threshold voltage.

Generally, the margin is set assuming that the characteristic value of each element is the limit value of the allowable range of manufacturing variation. On the other hand, many elements have characteristic values close to the average value of characteristic values of all elements. For this reason, when the margin is set as described above, the electric power generated by the piezoelectric element cannot be used effectively, and the electric power use efficiency may be relatively lowered.

The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the utilization efficiency of the electric power generated by the piezoelectric element in the power generation device including the piezoelectric element.

Another object of the present invention is to improve the utilization efficiency of electric power generated by a piezoelectric element in an electric device including a power generation device and an electric load that consumes electric power supplied from the power generation device.

The power generation device according to an aspect of the present invention supplies power generated by receiving external force to the output node. The power generation device includes a movable portion that is displaced according to an external force, a piezoelectric element that generates power by being deformed according to the displacement of the movable portion, a limiting portion configured to limit the displacement of the movable portion, and a switch. Prepare. The switch is connected in series to a power line connecting the piezoelectric element and the output node, and is configured to conduct when the displacement amount of the movable portion reaches the displacement amount limited by the limiting portion.

An electrical device according to another aspect of the present invention includes the above power generation device and an external load. The external load receives power supplied from the power generation device via the output node.

Preferably, the external load consumes the electric power supplied from the power generator when the switch is in a conductive state.

Preferably, the limiting unit is configured such that when the deformation amount of the piezoelectric element reaches a predetermined value or more, the displacement amount of the movable unit reaches a displacement amount limited by the limiting unit.

Preferably, the predetermined value is a maximum value of an allowable deformation amount of the piezoelectric element.
Preferably, the piezoelectric element includes first and second output terminals. The power generation device further includes a full-wave rectifier circuit, a capacitor, and another switch. The full-wave rectifier circuit is connected between the first and second output terminals and the output node, and full-wave rectifies the output voltage of the piezoelectric element. The capacitor is connected in parallel to the full wave rectifier circuit and smoothes the voltage rectified by the full wave rectifier circuit. The limiting unit includes a first limiting unit configured to limit the displacement of the movable unit in a direction in which the deformation amount of the piezoelectric element is increased, and the displacement of the movable unit in a direction in which the deformation amount of the piezoelectric element is decreased. And a second restriction unit configured to restrict. The other switch is connected in parallel to the switch. The switch is configured to conduct when the displacement amount of the movable portion reaches the displacement amount limited by the first limiting portion. The other switch is configured to conduct when the amount of displacement of the movable portion reaches the amount of displacement limited by the second limiting portion.

Preferably, the piezoelectric element includes first and second output terminals. The power generator further includes a discharge switch connected to the first and second output terminals. The discharge switch is configured to be in a conductive state after the switch is in a conductive state.

Preferably, the piezoelectric element includes first and second output terminals. The power generation device further includes a diode having an anode and a cathode. The first output terminal is electrically connected to the cathode and the switch. The second output terminal is electrically connected to the anode.

Preferably, the switch includes a mechanical switch that conducts in accordance with the displacement of the movable part.
Preferably, the movable part includes a magnetic body. The switch includes a reed switch that is turned on by a change in the magnetic field according to the displacement of the movable part.

Preferably, the power generation device further includes a piezoelectric unit that deforms according to the displacement of the movable unit and outputs a control signal. The switch includes an electrical switch that conducts in response to a control signal from the piezoelectric unit.

According to the present invention, in a power generation device including a piezoelectric element, the utilization efficiency of electric power generated by the piezoelectric element can be improved.

In addition, according to the present invention, it is possible to improve the utilization efficiency of the electric power generated by the piezoelectric element in the electric device including the power generation device and the load.

1 is a circuit block diagram schematically showing a configuration of a remote controller equipped with a power generation device according to Embodiment 1. FIG. It is a figure which shows the structural example of a piezoelectric element. It is a figure which shows the other structural example of a piezoelectric element. It is a circuit block diagram which shows roughly the structure of the remote controller which mounts the electric power generation module which concerns on a comparative example. FIG. 3 is a diagram for explaining the configuration and operation of a piezoelectric element and a load switch in the first embodiment. 6 is a time chart for explaining the operation of the remote controller equipped with the power generation module according to the first embodiment. It is a figure for comparing the utilization efficiency of electric power between the power generation module which concerns on Embodiment 1, and the power generation module which concerns on a comparative example. It is a figure which shows the structure of the load switch employ | adopted as the electric power generation module which concerns on the modification 1 of Embodiment 1. FIG. It is a figure which shows the structure of the load switch employ | adopted as the electric power generation module which concerns on the modification 2 of Embodiment 1. FIG. 4 is a circuit block diagram schematically showing a configuration of a remote controller equipped with a power generation device according to Embodiment 2. FIG. FIG. 6 is a diagram illustrating a configuration of a piezoelectric element and a load switch in a second embodiment. 6 is a time chart for explaining the operation of a remote controller equipped with a power generation module according to a second embodiment. 6 is a circuit block diagram schematically showing a configuration of a remote controller equipped with a power generation module according to Embodiment 3. FIG. 10 is a time chart for explaining the operation of a remote controller equipped with a power generation module according to Embodiment 3. FIG. 6 is a circuit block diagram schematically showing a configuration of a remote controller equipped with a power generation module according to a fourth embodiment. 10 is a time chart for explaining the operation of a remote controller equipped with a power generation module according to a fourth embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

Hereinafter, a configuration in which a remote controller (or a wireless switch) is realized using a power generation module will be described as an embodiment of the present invention. However, the application of the electric device including the power generation device according to the present invention is not limited to this. The power generation device according to the present invention can be applied to any electric device including an electric load that consumes the electric power generated by the power generation device. Examples of such an electric device include a vibration sensor, a microphone, an ignition device, and the like.

[Embodiment 1]
FIG. 1 is a circuit block diagram schematically showing a configuration of a remote controller on which the power generation module according to Embodiment 1 is mounted. With reference to FIG. 1, the remote controller 100 includes a power generation module 10 and a communication unit 50.

The power generation module (power generation device) 10 supplies power to the communication unit 50 via the output nodes OUT1 and OUT2. The communication unit 50 includes an RF (Radio Frequency) circuit 52 and an RF antenna 54. The communication unit 50 is provided outside the power generation module 10 and receives power supplied from the power generation module 10. And the communication part 50 outputs RF signal as a control signal to the receiver (not shown) provided in the position away from the remote controller 100. FIG. The communication unit 50 may include a light emitting element such as an LED (Light Emitting Diode) instead of the RF circuit 52 and the RF antenna 54. The communication unit 50 corresponds to an “external load” according to the present invention. However, the configuration of the external load is not limited to this, and any mechanism that can convert electrical energy into another energy form (for example, light, radio wave, etc.) may be used.

The power generation module 10 includes the piezoelectric element 1, a half-wave rectifier circuit 21, a capacitor C, and a load switch 31. The load switch 31 corresponds to a “switch” according to the present invention.

The piezoelectric element 1 generates electric power by being deformed according to the displacement of the movable part 60 (see FIG. 5). The piezoelectric element 1 is provided with an output terminal T1 (first output terminal) and an output terminal T2 (second output terminal). Hereinafter, the potential of the output terminal T1 based on the potential of the output terminal T2 is referred to as an output voltage V1. The configuration of the piezoelectric element 1 will be described in detail with reference to FIGS.

The half-wave rectifier circuit 21 is connected between the output terminals T1 and T2 and the output nodes OUT1 and OUT2. Half-wave rectifier circuit 21 and output node OUT1 are electrically connected via load switch 31 by power line PL. Half-wave rectifier circuit 21 and output node OUT2 are electrically connected by power line GL. The power line GL is a ground wiring connected to the reference potential GND. The half-wave rectifier circuit 21 is a general single-phase half-wave rectifier circuit including a diode (not shown), for example, and half-wave rectifies the output voltage V1 of the piezoelectric element 1.

The capacitor C is connected between the power line PL and the power line GL. Capacitor C smoothes the voltage half-wave rectified by half-wave rectifier circuit 21. Hereinafter, a voltage obtained by smoothing the output voltage V1 by the capacitor C is referred to as a rectified voltage Vc.

The load switch 31 is a switch that switches between a power supply state and a cut-off state to the communication unit 50. The load switch 31 is connected in series to a power line PL that connects the power generation module 10 and the output node OUT1. In other words, with respect to the direction in which power is supplied from the piezoelectric element 1, the load switch 31 is provided upstream of the output node OUT1, and the communication unit 50 is provided downstream of the output node OUT1. The load switch 31 may be provided on the power line GL instead of the power line PL. The power line PL or the power line GL corresponds to a “power line” according to the present invention, and a wiring that connects (in parallel) between the power line PL and the power line GL (for example, a wiring to which a capacitor C is connected) according to the present invention. It does not correspond to a “power line”. The configuration of the load switch 31 will be described in detail with reference to FIG.

FIG. 2 is a diagram illustrating a configuration example of the piezoelectric element 1. FIG. 2A schematically shows the piezoelectric element 1 in a state (initial state) in which an external force F that is a force by a user operation is not applied, for example.

Referring to FIG. 2A, the piezoelectric element 1 is, for example, a unimorph type piezoelectric element. The piezoelectric element 1 has a double-supported beam structure. That is, both end portions of the piezoelectric element 1 are supported by the support portion 16. The piezoelectric element 1 may have a cantilever structure.

The piezoelectric element 1 includes a piezoelectric body 12 and a metal plate 14. As the material of the piezoelectric body 12, for example, lead zirconate titanate ceramics are employed. However, the material of the piezoelectric body 12 is not particularly limited, and lead-free piezoelectric ceramics (for example, potassium sodium niobate ceramics, alkali niobic ceramics, etc.) may be employed.

The piezoelectric element 1 has a flat plate shape when no external force F is applied. An electrode 12A is provided on one main surface of the piezoelectric body 12. An output terminal T1 is connected to the electrode 12A. An electrode 12B is provided on the other main surface of the piezoelectric body 12. The electrode 12B electrically connects the piezoelectric body 12 and the metal plate 14. An output terminal T2 is connected to the electrode 12B.

As shown in FIG. 2 (B), when an external force F is applied to the central portion of the piezoelectric element 1, the piezoelectric body 12 is deformed. As a result, polarization occurs in the piezoelectric body 12. In FIGS. 2B and 2C, positive charges are indicated by “+” and negative charges are indicated by “−”. Due to the polarization, the electrode 12A is positively charged, while the electrode 12B is negatively charged. Therefore, the potential of the output terminal T1 is higher than the potential of the output terminal T2. That is, the output voltage V1 of the piezoelectric element 1 becomes a positive voltage.

On the other hand, as shown in FIG. 2C, when the application of the external force F to the piezoelectric element 1 is stopped, the piezoelectric body 12 is initialized by the restoring force of the piezoelectric element 1 and the spring 80 (see FIG. 5). Return to the state. At this time, the polarity of charges generated in the piezoelectric element 1 is reversed. That is, the electrode 12A is negatively charged while the electrode 12B is positively charged. Therefore, the output voltage V1 of the piezoelectric element 1 becomes a negative voltage. As described above, the sign of the output voltage V1 of the piezoelectric element 1 is reversed in accordance with the application of the external force F to the piezoelectric element 1 and the stop of the application.

FIG. 3 is a diagram illustrating another configuration example of the piezoelectric element 1. As shown in FIG. 3, a stacked element in which a plurality of piezoelectric bodies 12 are stacked may be employed as the piezoelectric element 1A. As a result, the amount of charge generated by the piezoelectric body 12 is larger than that of the single-layer type (see FIG. 2) configuration, so that a large amount of power can be supplied to the communication unit 50 (see FIG. 1). Although not shown, a bimorph type piezoelectric element 1A may be employed.

Here, in order to facilitate understanding of the characteristics of the power generation module 10 according to the first embodiment, the configuration of the power generation module according to the comparative example will be described.

FIG. 4 is a circuit block diagram schematically showing the configuration of a remote controller equipped with a power generation module according to a comparative example. Referring to FIG. 4, in remote controller 900, power generation module 90 is provided with a load switch 39 instead of load switch 31, and a control circuit 9 for controlling load switch 39 is further provided with the first embodiment. This is different from the power generation module 10 according to (see FIG. 1).

The control circuit 9 is connected between the power line PL and the power line GL. Although not shown, the control circuit 9 includes a comparator circuit and a reference voltage generation circuit, for example. When the rectified voltage Vc after the output voltage V1 is smoothed by the capacitor C becomes higher than the lowest operating voltage of the control circuit 9, the control circuit 9 starts operation using the rectified voltage Vc as the power supply voltage. The control circuit 9 detects the rectified voltage Vc, and determines the magnitude relationship between the detected rectified voltage Vc and a predetermined threshold voltage Vth. Then, the control circuit 9 outputs a control signal CTR corresponding to the determination result to the load switch 39. The conduction state and non-conduction state of the load switch 39 are switched by the control signal CTR.

Since circuits such as the comparator circuit and the reference voltage generation circuit are formed including semiconductor elements, they may include manufacturing variations. Furthermore, the piezoelectric element 1 can also include manufacturing variations. Therefore, there is a possibility that the determination result varies due to manufacturing variation of each element, and the power supply control operation may not be appropriately executed depending on the power generation module 90. Therefore, in order to ensure the reliability of the power generation module 90, it is desirable to set a margin in consideration of device manufacturing variations when setting the threshold voltage Vth.

Generally, the margin is set assuming that the characteristic value of each element is a limit value (upper limit value or lower limit value) of an allowable range of manufacturing variation. On the other hand, many elements have characteristic values close to the average value of characteristic values of all elements. For this reason, when the margin is set as described above, the electric power generated by the piezoelectric element 1 cannot be used effectively, and there is a possibility that the power use efficiency becomes relatively low.

Therefore, according to the present embodiment, instead of determining the magnitude relationship between the rectified voltage Vc and the threshold voltage Vth, a configuration is adopted in which the load switch 31 is conducted by a mechanical action when the external force F is applied. The Hereinafter, the structure and operation of the load switch 31 in the present embodiment will be described in detail.

FIG. 5 is a diagram for explaining the configuration and operation of the piezoelectric element 1 and the load switch 31 in the first embodiment.

Referring to FIG. 5A, the power generation module 10 includes the piezoelectric element 1, a load switch 31, a movable part 60, a base part 70, and a spring 80. The movable part 60 includes a hinge 62 and protrusions 64 and 66. The base part 70 includes a restriction part 71. As a material of the movable part 60 and the base part 70, an insulator such as a resin can be used.

In the following, for simplification of description, the positive z direction in the figure is called “upward” and the negative z direction is called “downward”. However, the negative z direction does not mean a vertical direction, and can be an arbitrary direction.

The movable part 60 is formed in a flat plate shape, for example. One end of the movable portion 60 is coupled to the base portion 70 by a hinge 62. One end of the spring 80 is connected to the vicinity of the other end of the movable portion 60. The other end of the spring 80 is fixed to the base 70. Thereby, the movable part 60 is displaced between the uppermost point and the lowermost point of the movable range R.

The base 70 is a portion corresponding to the housing of the power generation module 10, and the piezoelectric element 1 is provided on the bottom surface of the base 70. Further, a load switch 31 is provided on the upper surface of the restricting portion 71.

As shown in FIG. 5B, when the movable portion 60 is displaced downward by the application of the external force F, the protrusion 64 is pressed against the piezoelectric element 1. As a result, the piezoelectric element 1 is deformed, and the output voltage V1 is output from the piezoelectric element 1.

As shown in FIG. 5C, when the movable part 60 is pushed further downward, the movable part 60 reaches the lowest point of the movable range R. That is, the downward displacement of the movable part 60 is restricted by the restriction part 71. At this time, the protrusion 66 is in mechanical contact with the load switch 31 so that the load switch 31 becomes conductive. In other words, the load switch 31 becomes conductive when the displacement amount of the movable portion 60 reaches the displacement amount limited by the limiting portion 71.

FIG. 6 is a time chart for explaining the operation of the remote controller 100 equipped with the power generation module 10 according to the first embodiment. In FIG. 6 and FIGS. 12, 14 and 16 described later, the horizontal axis represents the elapsed time. The vertical axis indicates, in order from the top, the output voltage V1 and the rectified voltage Vc of the piezoelectric element 1, the conduction / non-conduction state of the load switch 31, and the operation / stop state of the communication unit 50.

Referring to FIG. 1, FIG. 5, and FIG. 6, deformation of piezoelectric element 1 due to application of external force F does not occur until time t11 (see FIG. 5A). Therefore, the output voltage V1 and the rectified voltage Vc are both substantially zero V (volts). The load switch 31 is in an initial state and is in a non-conductive state. Therefore, no power is supplied to the communication unit 50 and the communication unit 50 is stopped.

At time t11, deformation of the piezoelectric element 1 is started by the application of the external force F by the user (see FIG. 5B). Along with this, the output voltage V1 of the piezoelectric element 1 increases. As the output voltage V1 increases, the rectified voltage Vc also increases. On the other hand, since the load switch 31 is maintained in the non-conductive state, the power supply to the communication unit 50 is interrupted.

At time t12, the movable part 60 reaches the lowest point of the movable range R (see FIG. 5C). Then, the protrusion 66 mechanically contacts the load switch 31, and the load switch 31 is switched from the non-conductive state to the conductive state. As a result, power is supplied to the communication unit 50, and the communication unit 50 operates to consume power supplied from the power generation module 10 via the output node OUT1.

During the period from time t12 to time t13, the application of the external force F to the movable part 60 is continued, and the load switch 31 is maintained in the conductive state. Therefore, when the communication unit 50 continues its operation, the output voltage V1 and the rectified voltage Vc of the piezoelectric element 1 are lowered by an amount corresponding to the power consumed by the communication unit 50.

When the rectified voltage Vc falls below the minimum operating voltage Vmin of the communication unit 50 at time t13, the communication unit 50 stops. However, during the period from time t13 to time t14, the rectified voltage Vc slightly decreases due to the leakage current from the capacitor C.

When the user loosens the force (external force F) applied to the movable part 60 at time t14, the external force F starts to decrease. Accordingly, in the process in which the piezoelectric element 1 returns to the initial state (see FIG. 5A) by its restoring force, a negative voltage is output from the piezoelectric element 1 as the output voltage V1 (time t15). The negative voltage is half-wave rectified by the half-wave rectifier circuit 21, so that the rectified voltage Vc after time t15 becomes substantially zero V.

FIG. 7 is a diagram for comparing the power use efficiency between the power generation module 10 according to Embodiment 1 (see FIG. 1) and the power generation module 90 according to the comparative example (see FIG. 4). The power use efficiency means the proportion of power that can be supplied to the communication unit 50 in the power (generated power) generated by the piezoelectric element 1. In FIG. 7, the horizontal axis indicates the external force F applied to the piezoelectric element 1. The left vertical axis represents the amount of deformation of the piezoelectric element 1 (1A), and the right vertical axis represents the rectified voltage Vc.

Referring to FIG. 7, a curve DIS indicated by a one-dot chain line represents a deformation amount of the piezoelectric element 1. Due to manufacturing variations of the piezoelectric element 1, the rectified voltage Vc may vary from one piezoelectric element 1 to another even if the deformation amount of the piezoelectric element 1 is equal. A curve LL indicated by a solid line represents the rectified voltage Vc at the lower limit of the allowable range of manufacturing variation.

In the comparative example, the threshold voltage Vth to be compared with the rectified voltage Vc may also vary. The load switch 39 is turned on at the latest when the rectified voltage Vc indicated by the curve LL exceeds the maximum value of the threshold voltage Vth (the upper limit value of the allowable range). The external force F at this time is f9 which is smaller than f1 which is an external force corresponding to the lowest point of the movable range R of the movable part 60.

On the other hand, according to the first embodiment, the protrusion 66 provided on the movable portion 60 is in mechanical contact with the load switch 31 so that the load switch 31 becomes conductive. Therefore, unlike the comparative example, it is not necessary to consider the variation of the rectified voltage Vc and the threshold voltage Vth. Therefore, the load switch 31 is turned on after allowing deformation of the piezoelectric element 1 until the external force F reaches f1. Is possible. Therefore, the power corresponding to the area S indicated by the oblique lines can be used effectively. Therefore, the utilization efficiency of the electric power generated by the piezoelectric element 1 can be improved.

[Variation 1 of Embodiment 1]
In the first embodiment, the configuration in which a mechanical switch is employed as the load switch 31 has been described as an example. However, the type of the load switch 31 is not limited to this. In the first and second modifications of the first embodiment, a configuration in which a type of switch different from the mechanical switch is employed will be described.

FIG. 8 is a diagram for explaining the configuration of the load switch employed in the power generation module according to the first modification of the first embodiment. With reference to FIG. 8, the load switch 33 in the modification 1 is a reed switch provided in the inside of the glass tube with which the inert gas was enclosed. A magnet 68 for switching the contact point of the load switch 33 is embedded in the movable portion 60.

[Modification 2 of Embodiment 1]
FIG. 9 is a diagram for explaining a configuration of a load switch employed in the power generation module according to the second modification of the first embodiment. With reference to FIG. 9A, in Modification 2, another piezoelectric portion 1 </ b> B is provided below the piezoelectric element 1. Therefore, when the movable part 60 is displaced by the application of the external force F, the piezoelectric element 1 is deformed to generate power and the piezoelectric part 1B is also deformed to generate power. The conduction signal CON is output using the voltage generated by the piezoelectric unit 1B. The load switch 34 conducts in response to a conduction signal CON from the piezoelectric unit 1B.

FIG. 9B is a diagram illustrating a circuit configuration example of a peripheral circuit of the piezoelectric unit 1B. The peripheral circuit of the piezoelectric unit 1B includes switching elements (transistors) Q1 and Q2, diodes D1 to D3, and a resistor R1. When the switching elements Q1 and Q2 are turned on in response to the output voltage from the piezoelectric unit 1B, the conduction signal CON is output. The configuration other than the load switches 33 and 34 of the power generation module according to the first and second modifications of the first embodiment is the same as the corresponding configuration of the power generation module 10 according to the first embodiment. Do not repeat.

[Embodiment 2]
In the first embodiment, the configuration in which one load switch is provided has been described. However, a plurality of load switches may be provided. In the second embodiment, a configuration in which two load switches are provided will be described.

FIG. 10 is a circuit block diagram schematically showing a configuration of a remote controller equipped with the power generation module according to the second embodiment. Referring to FIG. 10, in remote controller 100A, power generation module 10A further includes a full-wave rectifier circuit 22 instead of half-wave rectifier circuit 21, and a load switch 32 connected in parallel to load switch 31. In this respect, it differs from the power generation module 10 (see FIG. 1) according to the first embodiment. The full wave rectifier circuit 22 is, for example, a general diode bridge circuit, and full wave rectifies the output voltage V1 of the piezoelectric element 1.

FIG. 11 is a diagram showing the configuration of the piezoelectric element 1 and the load switches 31 and 32 in the second embodiment. Referring to FIG. 11, base portion 70 </ b> A includes a limiting portion 72 (second limiting portion) in addition to limiting portion 71 (first limiting portion). The limiting unit 72 is provided above the movable unit 60. A load switch 32 is provided on the lower surface of the restricting portion 72. FIG. 11 shows a state in which the movable portion 60 has reached the uppermost point of the movable range R when the piezoelectric element 1 is restored.

When the piezoelectric element 1 is deformed, the load switch 31 is conducted, and when the piezoelectric element 1 is restored, the load switch 32 is conducted. Therefore, according to the second embodiment, as described below, the electric power generated by the piezoelectric element 1 can be supplied to the communication unit 50 both when the piezoelectric element 1 is deformed and when it is restored. The load switches 31 and 32 correspond to “switches” and “other switches” according to the present invention, respectively.

FIG. 12 is a time chart for explaining the operation of the remote controller 100A equipped with the power generation module 10A according to the second embodiment. The time chart shown in FIG. 12 is compared with the time chart of Embodiment 1 (see FIG. 6). In the time chart shown in FIG. 12, in addition to the load switch 31, the conduction / non-conduction state of the load switch 32 is further shown on the vertical axis.

Referring to FIGS. 10 to 12, since the movable part 60 is in mechanical contact with the load switch 32 during the period up to time t21, the load switch 32 is in a conductive state. However, since the output voltage V1 from the piezoelectric element 1 is substantially zero V, the communication unit 50 is stopped. Since the operation from time t21 to time t24 is equivalent to the operation from time t11 to time t14 in the time chart shown in FIG. 6, detailed description will not be repeated.

When the user loosens the external force F at time t24, the external force F starts to decrease. Accordingly, a negative voltage is output from the piezoelectric element 1 as the output voltage V1 in the process in which the piezoelectric element 1 returns to the initial state (the state until the time t21) by the restoring force. Since the full-wave rectifier circuit 22 is provided in the second embodiment, the rectified voltage Vc increases as time elapses due to the full-wave rectification of the negative voltage from the piezoelectric element 1.

At time t25, the movable part 60 reaches the highest point of the movable range R. In other words, the deformation amount of the piezoelectric element 1 reaches the deformation amount limited by the limiting unit 72. If it does so, the movable part 60 will contact the load switch 32 mechanically, and the load switch 32 will switch from a non-conduction state to a conduction | electrical_connection state. As a result, power is supplied to the communication unit 50 and the communication unit 50 operates.

After time t25, the load switch 32 is maintained in a conductive state. As the communication unit 50 operates during a period from time t25 to time t26, the output voltage V1 and the rectified voltage Vc of the piezoelectric element 1 are lowered by an amount corresponding to the power consumed by the communication unit 50. When the rectified voltage Vc falls below the minimum drive voltage Vmin of the communication unit 50 at time t26, the communication unit 50 stops.

As described above, according to the second embodiment, by providing the two load switches 31 and 32 and the full-wave rectifier circuit 22, power is supplied to the communication unit 50 twice by applying the external force F once. It becomes possible. As a result, the communication unit 50 can be operated twice.

[Embodiment 3]
In the third embodiment, a configuration in which a discharge switch for discharging charges generated in the piezoelectric element 1 is further provided will be described.

FIG. 13 is a circuit block diagram schematically showing a configuration of a remote controller equipped with the power generation module according to the third embodiment. Referring to FIG. 13, in remote controller 100B, power generation module 10B is different from power generation module 10A according to Embodiment 2 (see FIG. 10) in that it further includes discharge switch 4 and input node IN. The discharge switch 4 is connected to the output terminals T1 and T2 of the piezoelectric element 1.

The communication unit 50B is different from the communication unit 50 in the second embodiment in that it further includes an output circuit 56. The output circuit 56 outputs the discharge signal DCH after the load switches 31 and 32 are turned on and the communication unit 50 operates by receiving power supply (that is, after the RF signal is output from the RF antenna 54). Discharge signal DCH is transmitted to discharge switch 4 via input node IN. The discharge switch 4 switches from the non-conducting state to the conducting state in response to the discharge signal DCH. Thus, the discharge switch 4 is configured to be in a conductive state after the load switches 31 and 32 are in a conductive state. When the discharge switch 4 is turned on, the electric charge accumulated in the piezoelectric element 1 can be discharged.

FIG. 14 is a time chart for explaining the operation of the remote controller 100B according to the third embodiment. The time chart shown in FIG. 14 is compared with the time chart of the second embodiment (see FIG. 12). In the time chart shown in FIG. 14, the vertical axis further indicates the conduction / non-conduction state of the discharge switch 4.

Referring to FIGS. 13 and 14, the operation up to time t32 is the same as the operation up to time t22 in the time chart shown in FIG. 12, and therefore detailed description will not be repeated.

After time t32, the communication unit 50 consumes power supplied from the piezoelectric element 1 and executes output control of the RF signal. When this control is completed, the communication unit 50 outputs the discharge signal DCH (time t33). The discharge switch 4 is switched from the non-conductive state to the conductive state in response to the discharge signal DCH. As a result, the output terminal T1 and the output terminal T2 of the piezoelectric element 1 are short-circuited, so that the charge accumulated in the piezoelectric element 1 is discharged, and the output voltage V1 of the piezoelectric element 1 quickly reaches substantially zero V. .

On the other hand, the rectified voltage Vc gradually decreases due to power supply to the communication unit 50. When the rectified voltage Vc falls below the minimum drive voltage Vmin of the communication unit 50 at time t34, the communication unit 50 stops. Thereby, the output of the discharge signal DCH is stopped, and the discharge switch 4 is switched from the conductive state to the non-conductive state.

When the user loosens the external force F at time t35, the external force F starts to decrease. Accordingly, a negative voltage is output from the piezoelectric element 1 as the output voltage V1 in the process in which the piezoelectric element 1 returns to the initial state by the restoring force.

Thereafter, the communication unit 50 performs output control of the RF signal at time t36 and output control of the discharge signal DCH at time t37. Since the operation after time t37 is equivalent to the operation from time t33 to time t34, the description will not be repeated.

In Embodiment 2, since the discharge switch is not provided, the electric charge accumulated in the piezoelectric element 1 is not discharged. Therefore, in the process in which the piezoelectric element 1 returns to the initial state, the output voltage V1 of the piezoelectric element 1 increases in the negative direction starting from a positive value (see time t24 in FIG. 12). Then, the rectified voltage Vc when the movable part 60 reaches the uppermost point is necessarily lower than the rectified voltage Vc when the movable part 60 reaches the lowest point (see time t22 and time t25). The positive value increases as the accumulated charge of the piezoelectric element 1 increases. Therefore, when the accumulated charge of the piezoelectric element 1 is relatively large, the rectified voltage Vc when the movable part 60 reaches the highest point is lower than the lowest operating voltage Vmin of the communication part 50, and the communication part 50 is normally operated. It may not work.

On the other hand, in Embodiment 3, the accumulated charge of the piezoelectric element 1 is discharged by the discharge switch 4. Therefore, in the process in which the piezoelectric element 1 returns to the initial state, the output voltage V1 of the piezoelectric element 1 increases in the negative direction starting from substantially zero V (see time t35 in FIG. 14). Then, the rectified voltage Vc when the movable part 60 reaches the lowest point becomes substantially equal to the rectified voltage Vc when the movable part 60 reaches the lowest point (see time t32 and time t35). As a result, the rectified voltage Vc when the movable part 60 reaches the highest point becomes higher than the lowest operating voltage Vmin of the communication part 50. Therefore, the communication unit 50 can be more reliably operated twice by applying the external force F once.

[Embodiment 4]
In the fourth embodiment, a configuration in which a diode is provided instead of the rectifier circuit and the smoothing capacitor will be described.

FIG. 15 is a circuit block diagram schematically showing a configuration of a remote controller equipped with the power generation module according to the fourth embodiment. Referring to FIG. 15, in remote controller 100 </ b> C, power generation module 10 </ b> C includes diode D instead of half-wave rectifier circuit 21 and capacitor C, with respect to power generation module 10 according to Embodiment 1 (see FIG. 1). Different.

The output terminal T1 of the piezoelectric element 1 is electrically connected to the cathode of the diode D and the load switch 31. That is, the cathode of the diode D and the load switch 31 are directly connected. The output terminal T2 of the piezoelectric element 1 is electrically connected to the anode of the diode D.

FIG. 16 is a time chart for explaining the operation of the remote controller 100C equipped with the power generation module 10C according to the fourth embodiment. The time chart shown in FIG. 16 is compared with the time chart of the first embodiment (see FIG. 6). The output voltage V1 of the piezoelectric element 1 in the fourth embodiment is indicated by a solid line, and the output voltage V1 of the piezoelectric element 1 in the first embodiment is indicated by a broken line.

Referring to FIGS. 15 and 16, the operation up to time t44 is the same as the operation up to time t24 in the time chart shown in FIG. 6, and therefore detailed description will not be repeated.

When the user loosens the external force F at time t44, the external force F starts to decrease. Accordingly, in the process in which the piezoelectric element 1 returns to the initial state (see FIG. 5A) by the restoring force, a negative voltage is output from the piezoelectric element 1 as the output voltage V1. Then, a current flows from the output terminal T2 of the piezoelectric element 1 to the output terminal T1 through the anode and cathode of the diode D, whereby the charge accumulated in the piezoelectric element 1 is discharged. As a result, the output voltage V1 of the piezoelectric element 1 quickly reaches substantially zero V.

In Embodiment 1, since the electric charge accumulated in the piezoelectric element 1 is not discharged, the output voltage V1 becomes a negative value in the process of returning the piezoelectric element 1 to the initial state (see time t45 and thereafter). Therefore, although not shown, when the external force F is applied again (second time), the output voltage V1 increases in the positive direction starting from a negative value. Therefore, the rectified voltage Vc becomes lower than the minimum operating voltage Vmin of the communication unit 50, and the communication unit 50 may not operate normally.

On the other hand, in Embodiment 4, the accumulated charge of the piezoelectric element 1 is discharged via the diode D. Therefore, the output voltage V1 becomes substantially zero V in the process of returning the piezoelectric element 1 to the initial state. Therefore, when the external force F is applied again, the output voltage V1 increases starting from substantially zero V. In other words, the power generation module 10C at the start of the second operation returns to the state at the start of the first operation (the state at time t31). Therefore, the communication unit 50 can be reliably operated in the second and subsequent operations as in the first operation.

Furthermore, according to the fourth embodiment, the power generation module 10C is not provided with a rectifier circuit and a capacitor. Therefore, the occurrence of energy loss in the rectifier circuit (diode constituting the rectifier circuit) and the capacitor is suppressed. Therefore, the utilization efficiency of the electric power generated by the piezoelectric element 1 can be further improved by an amount corresponding to the energy loss.

In FIG. 7, it has been described that when the deformation amount of the piezoelectric element 1 reaches the maximum value, the displacement amount of the movable portion 60 reaches the displacement amount limited by the limiting portion 71. Not required. When the deformation amount of the piezoelectric element 1 reaches a design value (predetermined value) determined by experiment or simulation, the displacement amount of the movable unit 60 may reach the displacement amount limited by the limiting unit 71.

Further, the load switch 33 (reed switch: see FIG. 8) shown in the first modification of the first embodiment and the load switch 34 (electric switch: see FIG. 9) shown in the second modification are the same as those in the second embodiment. The power generation modules 10A to 10C according to the fourth to fourth embodiments can be applied as appropriate.

Furthermore, in Embodiments 1 to 4, the remote controller is taken as an example, and thus the force by the user operation has been described as the external force F. However, the external force F is not particularly limited as long as it is a force applied to the power generation module from the outside of the power generation module. The external force F may be a force applied by an actuator outside the power generation module, for example, or may be a force generated by an impact or vibration when the power generation module is transported.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1, 1A piezoelectric element, 1B piezoelectric part, 12 piezoelectric body, 12A, 12B electrode, 14 metal plate, 16 support part, 21 half-wave rectifier circuit, 22 full-wave rectifier circuit, 31-34, 39 load switch, 4 discharge switch , 9 control circuit, 10, 10A-10C power generation module, 50, 50B communication unit, 52 RF circuit, 54 RF antenna, 56 output circuit, 60 movable unit, 62 hinge, 64, 66 protrusion, 68 magnet, 70 base, 71 , 72 limiting unit, 80 spring, 100, 100A to 100C, 900 remote controller, C capacitor, D, D1, D3 diode, Q1, Q2 switching element, R1 resistor, IN input node, OUT1, OUT2 output node, T1, T2 Output terminal.

Claims (11)

A power generator that supplies power generated by receiving external force to an output node,
A movable part that is displaced according to the external force;
A piezoelectric element that generates electric power by being deformed according to the displacement of the movable part;
A limiting portion configured to limit the displacement of the movable portion;
A switch connected in series to a power line connecting the piezoelectric element and the output node, and configured to be conductive when the displacement amount of the movable portion reaches a displacement amount limited by the limiting portion. , Power generator. A power generator according to claim 1;
And an external load that receives electric power supplied from the power generation device via the output node. The electric device according to claim 2, wherein the external load consumes electric power supplied from the power generation device when the switch is in a conductive state. The restriction unit is configured such that when the deformation amount of the piezoelectric element reaches a predetermined value or more, the displacement amount of the movable unit reaches a displacement amount restricted by the restriction unit. 3. The electric device according to 3. The electric device according to claim 4, wherein the predetermined value is a maximum value of an allowable deformation amount of the piezoelectric element. The piezoelectric element includes first and second output terminals,
The power generator is
A full-wave rectifier circuit connected between the first and second output terminals and the output node, for full-wave rectifying the output voltage of the piezoelectric element;
A capacitor connected in parallel to the full-wave rectifier circuit and smoothing the voltage rectified by the full-wave rectifier circuit;
And further comprising another switch connected in parallel to the switch,
The restriction unit is
A first limiter configured to limit the displacement of the movable part in a direction to increase the amount of deformation of the piezoelectric element;
A second limiter configured to limit the displacement of the movable part in a direction to reduce the amount of deformation of the piezoelectric element;
The switch is configured to conduct when a displacement amount of the movable portion reaches a displacement amount restricted by the first restriction portion,
6. The switch according to claim 2, wherein the other switch is configured to be turned on when a displacement amount of the movable portion reaches a displacement amount limited by the second restriction portion. The electrical equipment described. The piezoelectric element includes first and second output terminals,
The power generator further includes a discharge switch connected to the first and second output terminals,
The electrical device according to any one of claims 2 to 5, wherein the discharge switch is configured to be in a conductive state after the switch is in a conductive state. The piezoelectric element includes first and second output terminals,
The power generator further comprises a diode having an anode and a cathode,
The first output terminal is electrically connected to the cathode and the switch;
The electrical apparatus according to any one of claims 2 to 5, wherein the second output terminal is electrically connected to the anode. The electrical device according to any one of claims 2 to 8, wherein the switch includes a mechanical switch that conducts according to a displacement of the movable portion. The movable part includes a magnetic body,
The electrical device according to any one of claims 2 to 8, wherein the switch includes a reed switch that is turned on by a change in a magnetic field according to a displacement of the movable part. Further comprising a piezoelectric part that deforms according to the displacement of the movable part and outputs a signal;
The electrical device according to any one of claims 2 to 8, wherein the switch includes an electrical switch that conducts in response to a signal from the piezoelectric unit.

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