WO2018061499A1

WO2018061499A1 - Piezoelectric power generation device and transmitter equipped with same

Info

Publication number: WO2018061499A1
Application number: PCT/JP2017/029361
Authority: WO
Inventors: 春田　一政
Original assignee: 株式会社村田製作所
Priority date: 2016-09-29
Filing date: 2017-08-15
Publication date: 2018-04-05
Also published as: JP6465259B2; JPWO2018061499A1

Abstract

A piezoelectric power generation device (100) equipped with a lever (2), a piezoelectric power generation body (7), a reverse spring (4), a DC/DC converter (104), and a signal output unit (103). The reverse spring (4) is arranged between the lever (2) and the piezoelectric power generation body (7), and reverses in conjunction with displacement of the lever (2). When an H-level enable signal (Sen) is received the DC/DC converter (104) converts the voltage of the power generated by the piezoelectric power generation body (7). The amount of deformation (Δd) of the piezoelectric power generation body (7) temporarily decreases in conjunction with the reversing of the reverse spring (4), even when the amount of displacement (Δz) of the lever (2) increases. The signal output unit (103) includes a delay circuit (106) that delays the output timing of the enable signal (Sen) by a delay time (ΔT) with respect to the reversal timing of the reverse spring (4).

Description

Piezoelectric generator and transmitter having the same

The present disclosure relates to a piezoelectric power generation device and a transmitter including the same.

The piezoelectric power generator is configured to include one or a plurality of piezoelectric elements, and generates a voltage corresponding to the deformation amount by being deformed by receiving an external force. Various piezoelectric power generation devices using this property have been proposed (see, for example, International Publication No. 2015/029317 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2011-103729 (Patent Document 2)).

International Publication No. 2015/029317 JP 2011-103729 A

Generally, in a device provided with an operation button (for example, a remote controller), a configuration in which an inversion spring is arranged behind the operation button is known. When the user operates the operation button, the reversing spring is pressed together with the operation button, and the reversing spring is reversed (or buckled). Since the impact generated during the reversal is transmitted to the user's finger, the user is given a feeling of “pressing the operation button” (so-called click feeling), so that the operability of the operation button can be improved.

For example, there is a case where a reversing spring is applied to a piezoelectric power generation device for the reason of the above improvement in operability. In this case, in addition to a movable part (for example, a lever) provided with operation buttons and the like, a piezoelectric generator, a reversing spring disposed between the movable part and the piezoelectric generator, a voltage converter, a command output unit A configuration of a piezoelectric power generation device that further includes: A voltage converter (for example, a DC / DC converter) converts the voltage of the electric power generated by the piezoelectric power generator when receiving an operation command (for example, an enable signal of H (high) level). The command output unit outputs the operation command to the voltage conversion unit as the reversing spring is reversed.

The present inventors have found that the following problems arise in the piezoelectric power generation device having the above-described configuration. That is, immediately after the reversing spring is reversed, the deformation amount of the piezoelectric power generation body temporarily decreases (instantaneously) due to the difference in shape before and after the reversing spring is reversed, and takes a minimum value ( Details will be described later). Therefore, when the operation command is output immediately after the reversal of the reversing spring and the voltage conversion unit is operated, the power to be subjected to voltage conversion by the voltage conversion unit is relatively small, so that the load at the subsequent stage of the voltage conversion unit, etc. There is a possibility that sufficient power cannot be supplied.

The present disclosure has been made to solve the above-described problem, and an object of the present disclosure is to provide a technology capable of supplying a larger amount of power from a voltage conversion unit in a piezoelectric power generation apparatus and a transmitter including the piezoelectric power generation apparatus. .

The piezoelectric power generation device according to an aspect of the present disclosure includes a movable part, a piezoelectric power generation body, a reversing spring, a voltage conversion part, and a command output part. The movable part is displaced by receiving an external force. The piezoelectric power generator is deformed as the movable part is displaced, and generates a voltage corresponding to the amount of deformation. The reversing spring is disposed between the movable part and the piezoelectric power generator, and reverses with the displacement of the movable part. The voltage conversion unit converts the voltage of the electric power generated by the piezoelectric power generator when receiving an operation command. The command output unit outputs an operation command to the voltage conversion unit as the reversing spring is reversed. The amount of deformation of the piezoelectric power generator temporarily decreases with the reversal of the reversal spring, even if the displacement of the movable part is increased. The command output unit includes a delay circuit that delays the output timing of the operation command by a predetermined time from the inversion timing of the inversion spring.

Preferably, the predetermined time is set to a time required for the amount of deformation of the piezoelectric power generator after the reversal of the reversing spring to be equal to or greater than the amount of deformation at the start of reversal of the reversing spring accompanying the displacement of the movable part.

Preferably, the predetermined time is set to 100 milliseconds or less.
Preferably, the command output unit is configured to output an operation command with the reversal of the reversing spring and to output the operation command with a return from the reversal of the reversing spring. The delay circuit is configured so as to delay the output timing of the operation command when the reversing spring is inverted, while not delaying the output timing of the operation command when returning from the reversal of the reversing spring.

A transmitter according to another aspect of the present disclosure includes the piezoelectric power generation device and a transmission unit. The transmission unit receives power whose voltage has been converted by the voltage conversion unit, and transmits a radio signal using the power.

According to the present disclosure, it is possible to supply larger electric power from the voltage conversion unit in the piezoelectric power generation device and the transmitter including the piezoelectric power generation device.

It is a perspective view of the piezoelectric power generation device concerning this embodiment. It is a disassembled perspective view of the piezoelectric power generator shown in FIG. It is a conceptual diagram for demonstrating operation | movement of the piezoelectric power generator in this Embodiment. It is a circuit block diagram which shows roughly the structure of the transmitter which concerns on a comparative example. It is a figure which shows the logic circuit of a signal output part. FIG. 6 is a Venn diagram corresponding to the logic circuit shown in FIG. 5. It is a graph which shows the relationship between the displacement amount of the lever in a comparative example, and the deformation amount of a piezoelectric electric power generation body. It is a circuit block diagram which shows roughly the structure of the transmitting apparatus which concerns on this Embodiment. It is a graph which shows the relationship between the displacement amount of the lever in this Embodiment, and the deformation amount of a piezoelectric electric power generation body. It is a time chart for demonstrating an example of operation | movement of the transmitter in this Embodiment.

Hereinafter, embodiments of the present disclosure 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 the piezoelectric power generation device according to the present embodiment is applied to a transmitter functioning as a so-called remote controller will be described as an example. In this transmitter, power is generated by the piezoelectric power generation device using an external force (load) applied to the operation button when the user presses down the operation button. By using the generated power, the transmission unit operates and a predetermined radio signal is transmitted. Thus, the transmitter according to the present embodiment does not require a power source such as a dry battery that needs to be replaced.

[Embodiment]
<Mechanism of piezoelectric generator>
FIG. 1 is a perspective view of the piezoelectric power generation device according to the present embodiment. FIG. 2 is an exploded perspective view of the piezoelectric power generation device shown in FIG. With reference to FIG. 1 and FIG. 2, first, the mechanism of the piezoelectric power generation apparatus 100 according to the present embodiment will be described.

The piezoelectric power generating apparatus 100 includes a first flexible wiring board 1, a lever 2, a second flexible wiring board 3, a reversing spring 4, an auxiliary spring 5, a screw 6, a piezoelectric power generating body 7, and a case body. 8.

Operation buttons (not shown) are installed on the main surface on the side where the first flexible wiring board 1 is located in the casing of the transmitter 100A (see FIG. 4) (not shown). In the present embodiment, two operation buttons that can be operated independently are provided at the positions of arrows AR1 and AR2 shown in FIG. When the operation button is operated by the user, external forces Fx and Fy are applied to the piezoelectric power generation apparatus 100 in the directions of arrows AR1 and AR2, respectively.

The case body 8 is a member that serves as a base for supporting other components constituting the piezoelectric power generation device 100. The case body 8 has a box-like shape including a bottom plate portion 80 having a substantially rectangular shape in plan view and side wall portions 81 to 84 erected from four sides of the bottom plate portion 80. Other components constituting the piezoelectric power generation apparatus 100 are mainly accommodated in a space surrounded by the bottom plate portion 80 and the side wall portions 81 to 84.

Four support portions 85 are provided at the four corners of the bottom plate portion 80 so as to protrude from the inner bottom surface of the bottom plate portion 80, respectively. Each support portion 85 is a portion for supporting the piezoelectric power generator 7 so as to be able to bend and deform.

Shaft support holes

811 and 821 are provided at predetermined positions near the side wall 83 of the

side walls

81 and 82 so as to face each other. The shaft support holes 811 and 812 are portions for supporting the lever 2 so as to be rotatable.

The piezoelectric power generation body 7 includes a plurality of (four in the present embodiment) piezoelectric elements 71 having a rectangular shape in plan view. The piezoelectric elements 71 are stacked so that the thickness directions of the piezoelectric elements 71 coincide with each other. Each piezoelectric element 71 has flexibility, and generates a voltage corresponding to the amount of deformation (power generation) by being deformed in the thickness direction. As the piezoelectric element 71, any of a unimorph type, a bimorph type, and a multimorph type may be used. However, in the present embodiment, a multimorph type piezoelectric element 71 including a piezoelectric body in which a plurality of piezoelectric films are stacked is provided. used. The piezoelectric body is formed by laminating a plurality of piezoelectric films made of, for example, lead zirconate titanate ceramics. As the piezoelectric body, lead-free piezoelectric ceramics (potassium sodium niobate ceramics, alkali niobate ceramics, etc.) may be used.

The lever (movable part) 2 includes a base 20 having a substantially rectangular shape in plan view, and standing

walls

21 and 22 erected from two opposite sides of the base 20 so as to face each other. The base 20 is disposed so as to face the piezoelectric power generator 7. The standing

wall portions

21 and 22 are arranged so as to face the

side wall portions

81 and 82 of the case body 8, respectively.

A pair of screw holes 23 are provided at predetermined positions of the base 20. By attaching the screw 6 to each of the pair of screw holes 23, the second flexible wiring board 3 and the auxiliary spring 5 are fixed to the lever 2.

Shaft portions 211 and 221 are provided at predetermined positions on the outer surfaces of the standing

wall portions

21 and 22 and near the side wall portion 83 of the case body 8 so as to protrude outward. The shaft portions 211 and 221 are respectively supported by the shaft support holes 811 and 821 by being inserted into the shaft support holes 811 and 821 provided in the case body 8. Thereby, the lever 2 is rotatably supported by the case body 8 with the axis line connecting the shaft portions 211 and 221 as the rotation axis AX.

When the lever 2 is rotatably supported by the case body 8 and an external force is applied to the base portion 20 of the lever 2, the lever 2 is in a direction substantially along the thickness direction of the piezoelectric power generation body 7. It is displaced to. With the displacement of the lever 2, the external force received by the lever 2 is transmitted to the piezoelectric power generator 7 via the reversing spring 4 and the auxiliary spring 5. As a result, each piezoelectric element 71 is bent and deformed.

The first flexible wiring board 1 is provided on the main surface of the pair of main surfaces of the base 20 of the lever 2 on the side where the piezoelectric generator 7 is not located. The first flexible wiring board 1 is formed by forming various conductive patterns on the surface of a multilayer base material, and has switches X and Y at predetermined positions.

The switches X and Y are provided so as to be aligned along a direction parallel to the extending direction of the rotation axis AX of the lever 2. As a result, the switches X and Y are positioned to face the two operation buttons (not shown) described above. In the present embodiment, each of the switches X and Y is constituted by a membrane switch, but other types of switches can also be used.

The second flexible wiring board 3 is provided on the main surface of the pair of main surfaces of the base 20 of the lever 2 on the side where the piezoelectric power generator 7 is located. The second flexible wiring board 3 is formed by forming various conductive patterns on the surface of a single-layer or multilayer substrate. A reversing spring 4 and an auxiliary spring 5 are disposed between the second flexible wiring board 3 and the piezoelectric power generator 7.

The reversal spring 4 is mounted on a portion of the second flexible wiring board 3 that is located on the main surface of the base portion 20 of the lever 2 and that faces the central portion of the piezoelectric generator 7. The reversal spring 4 is constituted by a metal member having a dome shape or a laminated structure thereof, for example. The reversing spring 4 is in a posture that protrudes downward so that a space is formed between the second flexible wiring board 3 (that is, the top of the dome-shaped reversing spring 4 is positioned on the piezoelectric power generator 7 side). It is fixed to the second flexible wiring board 3. The reversal spring 4 is buckled so that the uneven shape is reversed when an external force is applied and a predetermined load is applied. On the other hand, when the external force is released, the buckling is canceled and the original spring is released. Return to shape.

By using the reversal spring 4, when the user depresses the operation button, the above buckling phenomenon occurs when the pressing stroke becomes a predetermined value or more, and the spring constant of the reversal spring 4 is instantaneously lowered. Thereby, the user can obtain a click feeling by applying an impact from the reversing spring 4, and the operability when operating the operation buttons is improved.

The second flexible wiring board 3 and the reversing spring 4 constitute a switch Z having a pair of contacts. One of the pair of contacts is constituted by a reversing spring 4. The other contact is provided as a conductive terminal (not shown) in a portion of the second flexible wiring board 3 that is covered by the reversal spring 4. With this configuration, the switch Z is turned off when the reversing spring 4 is not reversed (off), while the switch Z is turned on when the reversing spring 4 is reversed. can do. The configuration and operation of the switches X to Z will be described in more detail with reference to FIGS.

The auxiliary spring 5 has an elongated plate shape that is substantially V-shaped when viewed from the side, and is attached to the second flexible wiring board 3 so as to protrude downward so as to receive the reversing spring 4. The auxiliary spring 5 adjusts the spring constant for transmitting the external force received by the lever 2 to the piezoelectric power generator 7. By providing the auxiliary spring 5, it is possible to adjust the degree of click feeling by the reversing spring 4 and to correct the balance of the force applied to the piezoelectric power generator 7 and the reversing spring 4. Further, the provision of the auxiliary spring 5 ensures that the buckling phenomenon of the reversing spring 4 occurs when the user operates the operation button.

<Operation of piezoelectric generator>
Next, an operation when an external force is applied to the piezoelectric power generation device will be described. Since the switches X and Y basically have a common configuration, an example in which the switch X is pressed will be described below, and the illustration of the switch Y is omitted.

FIG. 3 is a conceptual diagram for explaining the operation of the piezoelectric power generation apparatus according to the present embodiment. FIG. 3A shows a state of the piezoelectric power generation apparatus 100 before the external force Fx is applied. In the piezoelectric power generation apparatus 100, the lever 2 is rotatably supported by the case body 8 with the point P1 as a fulcrum. A displacement amount of the lever 2 based on a state before the external force Fx is applied is denoted as Δz. Before the application of the external force Fx, the switches X and Z are both off.

As shown in FIG. 3B, when the application of the external force Fx to the lever 2 is started, the switch X is switched from OFF to ON. Further, the point P2 becomes a force point, and the lever 2 rotates and the point P3 becomes an action point, whereby a force is applied to the reversing spring 4 and the piezoelectric power generator 7. However, when the displacement amount Δz of the lever 2 reaches z1, the reversing spring 4 has a downwardly convex shape. Therefore, the reversing spring 4 and the switch Z are not in contact, and the switch Z remains off.

As shown in FIG. 3C, when the application of the external force Fx is continued, the reversing spring 4 is reversed when the displacement amount Δz of the lever 2 reaches z2. As a result, the reversing spring 4 and the switch Z come into contact with each other, and the switch Z is switched from OFF to ON.

As shown in FIG. 3D, as the external force Fx is further applied, the deformation amount Δd of the piezoelectric power generator 7 increases, and the power generation amount by the piezoelectric power generator 7 increases.

<Transmitter circuit configuration>
Next, an example of a circuit configuration of the transmitter when the piezoelectric power generation device configured as described above is applied to the transmitter will be described. In order to facilitate understanding of the transmitter according to the present embodiment, first, the circuit configuration of the transmitter according to the comparative example will be described.

<Comparative example>
FIG. 4 is a circuit block diagram schematically showing a configuration of a transmitter according to a comparative example. The transmitter 900 </ b> A includes a piezoelectric power generation device 900 and a transmission unit 200.

The transmission unit 200 is a load that operates with electric power supplied from the piezoelectric power generation device 100. More specifically, the transmission unit 200 includes, for example, an RF (Radio Frequency) antenna 201 and an RF circuit 202. The transmission unit 200 transmits an RF signal to a receiver (not shown) provided at a position away from the transmitter 900A using the electric power supplied from the piezoelectric power generation device 900. This RF signal may be a signal indicating a control command to the receiver, or a signal for transmitting various information to the receiver.

The piezoelectric power generator 900 includes a piezoelectric power generator 7, a discharge circuit 101, a full-wave rectifier circuit 102, a capacitor C, switches X to Z, a signal output unit 903, a DC / DC converter 104, and a control circuit 105. With.

The piezoelectric power generation body 7 includes a plurality of piezoelectric elements 71 (see FIG. 1 or 2) and output terminals T1 and T2. Hereinafter, the potential of the output terminal T1 based on the potential of the output terminal T2 is referred to as “output voltage V”.

The discharge circuit 101 is connected between the output terminal T1 and the output terminal T2 of the piezoelectric power generator 7, and is configured to be able to discharge the electric charge (or power) stored in the piezoelectric power generator 7. More specifically, discharge circuit 101 includes, for example, an NMOS (n-type Metal Oxide-Semiconductor) transistor, and switches from a non-conductive state (off) to a conductive state (on) in response to a discharge command from control circuit 105. And switch. When the discharge circuit 101 is turned on, the output terminal T1 and the output terminal T2 are short-circuited, so that the charge stored in the piezoelectric power generator 7 is discharged.

The full-wave rectifier circuit 102 is a general full-wave rectifier circuit such as a diode bridge, and is electrically connected between the piezoelectric generator 7 and the signal output unit 903. The full-wave rectifier circuit 102 performs full-wave rectification on the output voltage V of the piezoelectric generator 7 and outputs a rectified voltage (rectified voltage) Vc between the power line PL and the power line GL. The power line GL is electrically connected to the reference potential GND.

The capacitor C is electrically connected between the power line PL and the power line GL. The capacitor C smoothes the rectified voltage Vc.

The signal output unit 903 includes input nodes INx, INy, INz, diodes D1 to D4, resistors R1 to R5, a switching element Q, and an output node OUT. The switching element Q is, for example, an NMOS transistor.

Each of the switches X and Y has a pair of contacts. One of the pair of contacts of the switch X is electrically connected to the power line PL, and the other is electrically connected to the input node INx of the signal output unit 903. Similarly, one of the pair of contacts of the switch Y is electrically connected to the power line PL, and the other is electrically connected to the input node INy of the signal output unit 903.

The input node INx is electrically connected to the gate of the switching element Q via the diode D1. The anode of the diode D1 is electrically connected to the power line GL via the resistor R1. Similarly, the input node INy is electrically connected to the gate of the switching element Q via the diode D2. The anode of the diode D2 is electrically connected to the power line GL via the resistor R2. The gate of the switching element Q is electrically connected to the power line GL via the resistor R3.

The source of the switching element Q is electrically connected to the power line GL. The drain of the switching element Q is electrically connected to the power line PL via the resistor R4. The anode of the diode D3 is electrically connected to the connection node between the resistor R3 and the drain of the switching element Q. The cathode of the diode D3 is electrically connected to the output node OUT. A resistor R5 is electrically connected between the power line connecting the cathode of the diode D3 and the output node OUT and the power line GL.

As described above, the switch Z also has a pair of contacts. One contact of the switch Z is constituted by a reversing spring 4 (see FIG. 2), and is electrically connected to the power line PL. The other contact of the switch Z is constituted by a conductive terminal (not shown) provided on the second flexible wiring board 3 (see FIG. 2), and is electrically connected to the input node INz of the signal output unit 903. Yes. The input node INz is electrically connected to the anode of the diode D4. The cathode of the diode D4 is electrically connected to the output node OUT.

The DC / DC converter 104 is electrically connected to an input terminal Vin electrically connected to the power line PL, an output terminal Vout electrically connected to the control circuit 105 and the RF circuit 202, and an output node OUT of the signal output unit 903. And an enable terminal EN connected to each other. The DC / DC converter 104 boosts (or steps down) the rectified voltage Vc to a predetermined voltage based on the on / off states of the switches X, Y, and Z, and supplies the rectified voltage Vc to the control circuit 105 and the transmission unit 200. More specifically, the DC / DC converter 104 supplies power to the control circuit 105 and the transmission unit 200 when receiving the enable signal Sen at the H (high) level at the enable terminal EN, while the enable terminal EN When EN receives an L (low) level enable signal Sen, power is not supplied to the control circuit 105 and the transmitter 200.

The control circuit 105 is connected between the output terminal Vout of the DC / DC converter 104 and the power line GL, and operates by receiving power supply from the DC / DC converter 104. The control circuit 105 receives at least one of the signal Sx and the signal Sy and outputs an operation command corresponding to the received signal to the RF circuit 202. Further, the control circuit 105 outputs a discharge command to the discharge circuit 101 at a predetermined timing.

FIG. 5 is a diagram illustrating a logic circuit of the signal output unit 903. The signal output unit 903 includes input nodes INx, INy, INz, an output node OUT, a NOR circuit (negative OR circuit) 903A, and an OR circuit (logical OR circuit) 903B.

The NOR circuit 903A outputs, to the OR circuit 903B, a signal indicating a result of a negative OR operation between the signal input to the input node INx and the signal input to the input node INy. The OR circuit 903B outputs, to the output node OUT, an enable signal Sen indicating a logical OR operation result between the signal from the NOR circuit 903A and the signal input to the input node INz. The enable signal Sen from the output node OUT is transmitted to the enable terminal EN of the DC / DC converter 104.

In this way, the signal output unit 903 outputs the H level or L level enable signal Sen to the enable terminal EN of the DC / DC converter 104 in accordance with the combination of the on / off states of the switches X, Y, and Z. . What enable signal Sen is output from the signal output unit 903 in accordance with the combination of the states of the switches X, Y, and Z will be summarized below. The H level enable signal corresponds to an “operation command” according to the present disclosure.

FIG. 6 is a Venn diagram corresponding to the logic circuit shown in FIG. In the Venn diagram, regions where the enable signal Sen is at the H level are indicated by hatching. A region where the enable signal Sen is at the L level is shown in white without hatching.

When the switches X, Y, and Z are all off, an H level enable signal Sen is output as shown in the region K1 (see FIG. 3A).

When one of the switches X and Y is on, the other is off, and the switch Z is off, an L level enable signal Sen is output as shown in regions K2 and K3. (See FIG. 3B). Even when the switches X and Y are both on and the switch Z is off, the L level enable signal Sen is output as shown in the region K4.

When the switch Z is ON, the signal output unit 903 outputs an H level enable signal Sen. More specifically, when one of the switches X and Y is on, the other is off, and the switch Z is on, as shown in regions K6 and K7, the H level enable A signal Sen is output (see FIG. 3C). Even when all of the switches X, Y, and Z are on, as shown in the region K8, the H level enable signal Sen is output. In the present embodiment, the state in which the switch Z is on (see the region K5) even though both the switches X and Y are off does not actually occur.

In the piezoelectric power generation apparatus 900 configured as described above, the present inventors have found that the following problems occur.

FIG. 7 is a graph showing the relationship between the displacement amount Δz of the lever 2 and the deformation amount Δd of the piezoelectric generator 7 in the comparative example. In FIG. 7 and FIG. 9 described later, the horizontal axis indicates the displacement amount Δz of the lever 2 (that is, the amount by which the lever 2 is pushed by a user operation). The vertical axis represents the deformation amount Δd of the piezoelectric power generator 7. This deformation amount Δd can be read as the amount of power generated by the piezoelectric power generator 7.

As shown in FIG. 7, until the displacement amount Δz of the lever 2 reaches z1, the deformation amount Δd of the piezoelectric power generator 7 increases as the displacement amount Δz increases. Then, when the displacement amount Δz reaches z1, the deformation amount Δd takes the maximum value d1.

However, the reversing spring 4 is reversed immediately after the displacement amount Δz reaches z1 (see Δz = z2). As a result, due to the difference in the shape of the reversing spring 4 before and after reversal, the deformation amount Δd of the piezoelectric power generation body 7 temporarily decreases and takes the minimum value d2. Thereafter, until the lever 2 reaches the lowest point, the deformation amount Δd continues to increase as the displacement amount Δz increases (see Δz = z2 to z3).

3C, when the reversing spring 4 is reversed, the switch Z is turned on in addition to at least one of the switches X and Y. Then, since the H level enable signal Sen is output from the signal output unit 103 (see regions K6 to K8 in FIG. 6), the DC / DC converter 104 starts its operation.

Thus, in the comparative example, immediately after the reversal spring 4 is reversed, in other words, in the vicinity of the minimum value d2 of the deformation amount Δd of the piezoelectric generator 7 when the displacement amount Δz = z2 of the lever 2, the voltage conversion by the DC / DC converter 104 is performed. Will be performed. Therefore, the power for voltage conversion by the DC / DC converter 104 becomes relatively small, and there is a possibility that sufficient power cannot be supplied to the control circuit 105 and the transmitter 200 at the subsequent stage of the DC / DC converter 104. .

Therefore, in the present embodiment, a configuration is adopted in which the signal output unit 103 is provided with a delay circuit 106 for delaying the output timing of the enable signal Sen by the delay time ΔT from the inversion timing of the inversion spring 4.

<This embodiment>
FIG. 8 is a circuit block diagram schematically showing the configuration of the transmitter according to the present embodiment. A transmitter 100 </ b> A illustrated in FIG. 8 includes a piezoelectric power generation device 100 and a transmission unit 200. The piezoelectric power generation apparatus 100 includes a signal output unit 103 instead of the signal output unit 903 (see FIG. 4) in the comparative example. The signal output unit 103 is different from the signal output unit 903 in that it further includes a delay circuit 106. The signal output unit 103 corresponds to a “command output unit” according to the present disclosure.

The delay circuit 106 is, for example, a general RC delay circuit (integration circuit), and is provided on the transmission line of the enable signal Sen connecting the input node INz and the output node OUT. More specifically, delay circuit 106 includes a resistor R6 and a capacitor C6. The resistor R6 is electrically connected between the input node INz and the anode of the diode D4. Capacitor C6 is electrically connected between resistor R6 and an anode connection node of diode D4 and power line GL. Since the other configuration of transmitter 100A (piezoelectric power generation device 100 and transmitter 200) is the same as the corresponding configuration of transmitter 900A according to the comparative example, detailed description will not be repeated.

Next, a method for setting the delay time ΔT of the enable signal Sen by the delay circuit 106 will be described. The delay time ΔT corresponds to a “predetermined time” according to the present disclosure.

FIG. 9 is a graph showing the relationship between the displacement amount Δz of the lever 2 and the deformation amount Δd of the piezoelectric generator 7 in the present embodiment. As described with reference to FIG. 7, when the displacement amount Δz reaches z1, the deformation amount Δd of the piezoelectric power generator 7 takes the maximum value d1.

In the present embodiment, the delay time ΔT is equal to or more than the time required for the deformation amount Δd of the piezoelectric power generation body 7 to be greater than d1 after the switch Z is turned on as the reversing spring 4 is reversed. Is also determined to be longer. Thus, the enable signal Sen is output to the enable terminal EN of the DC / DC converter 104 in a state where the deformation amount Δd of the piezoelectric power generator 7 is not less than d1 and not more than d3 (d1 ≦ Δd ≦ d3). Therefore, sufficient power can be supplied from the DC / DC converter 104 to the control circuit 105 and the transmission unit 200.

On the other hand, if the delay time ΔT is excessively long, the user may feel uncomfortable. More specifically, the time difference between the time when the user operates the switch X or Y and the time when the RF signal is transmitted from the transmitter 100A to the receiver (not shown) and a predetermined operation is performed ( When the time lag becomes a length that can be sensed by the user, there is a possibility of giving the user a stress (uncomfortable feeling) that the operation is not immediately performed even though the switch is operated. In order not to give such stress to the user, the delay time ΔT is preferably short to some extent. In general, since a time lag of 100 ms or less is often not perceived by the user, the delay time ΔT is preferably set to 100 ms or less.

<Transmitter operation time chart>
Next, as an example of the operation of transmitter 100A, the operation of transmitter 100A when the user performs an operation of depressing an operation button (not shown) corresponding to switch X will be described in detail.

FIG. 10 is a time chart for explaining an example of the operation of transmitter 100A in the present embodiment. In FIG. 10, the horizontal axis indicates the elapsed time. The vertical axis represents the external force Fx on / off, the switch X on / off, the switch Y on / off, the switch Z on / off, and the potential (H level) of the enable terminal EN of the DC / DC converter 104 in order from the top. / L level), output voltage V of the piezoelectric generator 7, and on / off of the discharge command.

During the period up to time t1, since the switches X, Y, and Z are all off, the enable signal Sen of the signal output unit 103 is at the H level. Therefore, the potential of the enable terminal EN of the DC / DC converter 104 is at the H level (see region K1 in FIG. 6). However, since power generation by the piezoelectric power generator 7 has not yet been performed, the DC / DC converter 104 is not operating, and power supply from the piezoelectric power generation apparatus 100 to the transmission unit 200 is not performed.

Application of external force Fx is started at time t1, and switch X is turned on at time t2. Then, the potential of the enable terminal EN becomes L level (see the region K2 in FIG. 6). Almost simultaneously with time t2, the piezoelectric power generator 7 begins to bend and deform, and power generation by the piezoelectric power generator 7 is started along with this deformation. The electric power generated by the piezoelectric power generator 7 is stored in the piezoelectric power generator 7 without being supplied to the transmitter 200.

At time t3, the reversing spring 4 starts reversing. When the reversal of the reversing spring 4 is completed at time t4, the switch Z is turned on. In addition, a click feeling is given to the user due to the inversion that occurs in the period from time t3 to time t4.

At time t5 after the lapse of the delay time ΔT from time t4, the potential of the enable terminal EN becomes H level (see region K6 in FIG. 6). Thereby, the DC / DC converter 104 converts the voltage of the electric power stored in the piezoelectric power generator 7 and supplies it to the control circuit 105 and the transmission unit 200. The transmission unit 200 outputs an RF signal (not shown) indicating that the switch X is turned on (first transmission operation). Therefore, after time t5, the output voltage V of the piezoelectric power generator 7 decreases.

When the first transmission operation is completed, a discharge command is output from the control circuit 105 to the discharge circuit 101 at time t6. Thereby, the reset operation for discharging the electric charge stored in the piezoelectric power generator 7 is started. Specifically, the electrodes of the piezoelectric power generator are short-circuited, thereby resetting the output voltage of the piezoelectric power generator 7 to 0V. Thereafter, the output of the discharge command is stopped at time t7.

When the application of the external force Fx starts to be released at time t8, the reversing spring 4 starts reversing to return to the original shape, and the reversing from the reversing of the reversing spring 4 is completed at time t9. Then, the switch Z is turned off at substantially the same time as time t9. On the other hand, the switch X remains on.

At time t10 after the delay time ΔT has elapsed from time t9, the potential of the enable terminal EN becomes L level (see region K2 in FIG. 6). Thereby, the DC / DC converter 104 stops its operation.

Almost simultaneously with time t10, the bending deformation of the piezoelectric power generation body 7 starts to be eliminated as the external force Fx decreases. Along with this deformation, power generation by the piezoelectric power generator 7 is performed. The generated electric power is stored in the piezoelectric power generator 7 without being supplied to the transmitter 200.

When the switch X is turned off at time t11, the potential of the enable terminal EN becomes H level (see the region K1 in FIG. 6). Along with this, the DC / DC converter 104 converts the voltage of the electric power stored in the piezoelectric power generator 7 and supplies it to the control circuit 105 and the transmission unit 200. The transmitter 200 outputs an RF signal (not shown) indicating that the switch X has been turned off (second transmission operation).

At time t12, the application of the external force Fx ends. After time t12, power is supplied from the piezoelectric power generation apparatus 100 to the transmission unit 200, so that the output voltage V of the piezoelectric power generation body 7 decreases. Thereafter, during the period from time 13 to time 14, the reset operation similar to the period from time t6 to time t7 is performed.

Although description is omitted here, when the user operates an operation button (not shown) corresponding to the switch Y and when the user operates the operation buttons corresponding to the switches X and Y at the same time, A series of operations according to the above description will be performed.

As described above, according to the present embodiment, the timing at which the enable signal Sen is output to the enable terminal EN of the DC / DC converter 104 is the delay time ΔT by the delay circuit 106 provided in the signal output unit 103. Delayed. By appropriately determining the delay time ΔT, the potential of the enable terminal EN is switched from the L level to the H level when the deformation amount Δd of the piezoelectric power generation body 7 is d1 or more and d3 or less (d1 ≦ Δd ≦ d3). The voltage conversion operation of the DC / DC converter 104 is performed. As a result, sufficient power can be supplied to the control circuit 105 and the transmission unit 200.

Furthermore, in the transmitter 100A, two transmission operations (first and second transmission operations) are performed while the user operates the operation button only once. For example, the RF signal transmitted in the first transmission operation is different from the RF signal transmitted in the second transmission operation, and the receiver (see FIG. (Not shown) can be set to operate, so that malfunction of the receiver can be prevented. However, it is not essential that the transmission operation is performed twice, and only one of them may be performed.

If the purpose is to delay the enable signal Sen, a delay circuit 106 may be provided immediately before or after the output node OUT (that is, between the output node OUT and the enable terminal EN). However, in this case, the output timing of the enable signal Sen is delayed both when the reversing spring 4 is reversed (during the first transmission operation) and when the reverse spring 4 is restored (when the second transmission operation is performed).

On the other hand, in the present embodiment, the delay circuit 106 is provided after the input node INz. For this reason, the output timing of the enable signal Sen is delayed along with the switching of the ON state / OFF state of the switch Z (see times t4 and t9), while the switching of the ON state / OFF state of the switches X and Y (time) The output timing of the enable signal Sen is not delayed by t2 and t11). In other words, the output timing of the enable signal Sen is delayed at the time of the first transmission operation (at the time of reversal of the reversal spring 4), while the enable signal Sen at the time of the second transmission operation (at the time of reversal of the reversal spring 4). Does not delay output timing.

According to the measurement by the present inventor, a large amount of electric power is generated by the piezoelectric power generator 7 during the second transmission operation compared to during the first transmission operation. Therefore, in many cases, sufficient power can be supplied to the control circuit 105 and the transmission unit 200. Therefore, by configuring the delay circuit 106 so as not to delay the output timing of the enable signal Sen, the second transmission operation can be performed early.

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

1 First flexible wiring board, 2 lever, 20 base, 21, 22 standing wall, 211, 221 shaft, 23 screw holes, 3 second flexible wiring board, 4 reversing spring, 5 auxiliary spring, 6 screws, 7 Piezoelectric generator, 71 piezoelectric element, 8 case body, 80 bottom plate, 81, 82, 83, 84 side wall, 811, 812, 821 shaft support hole, 85 support, 100, 900 piezoelectric generator, 100A, 900A transmission Machine, 101 discharge circuit, 102 full-wave rectifier circuit, 103,903 signal output unit, 104 DC / DC converter, 105 control circuit, 106 delay circuit, 200 transmission unit, 201 antenna, 202 RF circuit, 903A NOR circuit, 903B OR Circuit, X, Y, Z switch, R1-R6 resistance, D1-D4 Dio De, C, C6 capacitor, Q switching element, GL, PL power line, INx, INy, INz input nodes, OUT output node, T1, T2, Vout output terminal, EN enable terminal.

Claims

A movable part that is displaced by receiving an external force;
A piezoelectric power generator that is deformed in accordance with the displacement of the movable part and generates a voltage corresponding to the amount of deformation;
A reversing spring disposed between the movable part and the piezoelectric power generation body and reversing with displacement of the movable part;
When receiving an operation command, a voltage converter that converts the voltage of the electric power generated by the piezoelectric generator, and
A command output unit that outputs the operation command to the voltage conversion unit in accordance with the reversal of the reversing spring;
The amount of deformation of the piezoelectric power generator temporarily decreases with the reversal of the reversing spring, even if the amount of displacement of the movable part increases.
The command output unit includes a delay circuit that delays an output timing of the operation command by a predetermined time from an inversion timing of the inversion spring.
The predetermined time is set to a time required for the deformation amount of the piezoelectric power generation body after the reversal of the reversal spring to be equal to or greater than the deformation amount at the start of reversal of the reversal spring with the displacement of the movable part. The piezoelectric power generation device according to claim 1.
The piezoelectric power generation device according to claim 1 or 2, wherein the predetermined time is set to 100 milliseconds or less.
The command output unit is configured to output the operation command along with reversal of the reversing spring, and to output the operation command upon return from reversal of the reversing spring,
The delay circuit is configured to delay the output timing of the operation command when the reversing spring is reversed, while not delaying the output timing of the operation command when returning from the reversal of the reversing spring. Item 4. The piezoelectric power generation device according to any one of Items 1 to 3.
The piezoelectric power generation device according to any one of claims 1 to 4,
A transmitter comprising: a transmitter that receives electric power whose voltage is converted by the voltage converter and transmits a radio signal using the electric power.