JP2012005192A - Power generation component, power generator using the same, and communication module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, if expanding a frequency band of high power generation amount in the power generation characteristic of a power generation component by arranging piezoelectric vibrators having different frequency characteristics, a piezoelectric element that contributes to power generation comes to be a single unit among a plurality of units at one moment, resulting in reduction in the maximum power generation amount when compared with a piezoelectric component having the same size.SOLUTION: There are provided a mechanical vibration propagation part 102 for propagating mechanical vibration, a first vibration part 103 connected to the mechanical vibration propagation part 102, and a second vibration part 104 connected to the mechanical vibration propagation part 102. The first vibration part 103 includes a first piezoelectric part 105, and the second vibration part 104 includes a second piezoelectric part 106. The first vibration part 103 and the second vibration part 104 are combined with each other through the mechanical vibration propagation part 102 so that a power generation component and a power generator are vibrated in symmetrical mode, or diagonally symmetrical mode, otherwise in both of them.

Description

  The present invention relates to a power generator using a piezoelectric component that generates electricity by external vibration or the like.

  With the advent of the society to connect to networks at home and on a global scale, the issue of how to supply energy to the myriad device terminals and sensor terminals used for them will arise. Thus, a self-supporting terminal that has a power generation system and enables independent power supply is desired. One of the key components is a power generation component that collects and uses dilute dispersed energy that is dispersed in the natural environment. One of the power generation parts using piezoelectric materials is to generate electricity using the so-called piezoelectric effect that changes stress or strain into electricity, and to take it out for use. The source of the stress is dilute dispersion energy, for example, vibration existing in the natural environment (hereinafter referred to as environmental vibration). There are various types of environmental vibrations, such as walking and running of the human body that vibrate at a frequency of 1 to 4 Hz, and devices such as homes and factories, or moving objects such as cars and trains, Many of them vibrate at a frequency of several tens to several hundreds of Hz. A power generation device using a piezoelectric material vibrates a power generation component having a cantilever structure with a weight or the like based on such environmental vibration, and extracts generated electricity (electric charge). And when the frequency (frequency) of environmental vibration is the natural frequency which a power generation component has, the electric power taken out becomes the maximum. Such a component usually has a Q value of 100 to several hundreds, vibrates at a natural frequency, and the energy that can be taken out at the time of so-called resonance is a maximum of 2 times the Q value compared to other times than resonance. It is equivalent to. That is, when trying to extract a large electric power, it is necessary to match the frequency of the environmental vibration and the resonance frequency of the piezoelectric component, and only the environmental vibration that matches the resonance characteristic of the piezoelectric component having a steep peak can be extracted. 17 and 18 show a conventional technique in which a plurality of piezoelectric elements having different resonance frequencies are arranged to broaden the frequency characteristic of the power generation device. In FIG. 18, 211a to 211c are piezoelectric vibrators, each having a different resonance frequency. The electric charges (current) generated by each vibrator are rectified by rectifier circuits 212a to 212c, smoothed by a capacitor 213, and taken out as a DC voltage. Here, 214 is a protective Zener diode. FIG. 17 shows the relationship between the amount of electric charge generated in each of the piezoelectric vibrators 211a to 211c and the frequency, and has different resonance characteristics such as 221a to 221c. It has been.

JP 07-245970 A

  However, since the method disclosed in Patent Document 1 uses piezoelectric vibrators having different frequency characteristics, if only environmental vibrations having a specific frequency can be obtained at a certain moment, out of three piezoelectric elements that contribute to power generation. It will be one. Therefore, the maximum power generation amount is reduced to about one third when compared with a piezoelectric component of the same size. In order to compensate for this, a device such as increasing the number of piezoelectric components or increasing the number of the piezoelectric components is required, and the power generation device is increased in size.

  Therefore, the present invention aims at widening the characteristics without reducing the substantial power generation amount by adopting a structure in which a plurality of piezoelectric parts can operate simultaneously. Broadbanding is realized by using a vibration mode different from the conventional one or by using a plurality of vibration modes. From the above, the object is to achieve both high power generation and downsizing of the device.

  In order to achieve this object, in the present invention, a mechanical vibration propagation unit that propagates mechanical vibration, a first vibration unit connected to the mechanical vibration propagation unit, and a second vibration unit connected to the mechanical vibration propagation unit are provided. The first vibration part has a first piezoelectric part, the second vibration part has a second piezoelectric part, and the first vibration part and the second vibration part are coupled via a mechanical vibration propagation part. The power generation component or the power generation device vibrates in the symmetric mode or the oblique symmetric mode or both.

  With the above configuration, it is possible to efficiently generate electric power by operating a plurality of vibration units at the same time, and it is possible to provide a power generation device that can cope with broadband environmental vibration without increasing the size of the power generation device.

Top view of power generation component in the first embodiment 1 is a cross-sectional view taken along one-dot chain line AB in FIG. (A) The top view which took out only the silicon part in 1st Embodiment, (b) Sectional drawing in the dashed-dotted line CD of (a) The top view which showed only the PZT part in 1st Embodiment The circuit diagram which shows the rectifier circuit and smoothing capacitor in 1st Embodiment The figure which shows the relationship between the electric power generation amount and frequency of the electric power generating apparatus in 1st Embodiment. The top view of the comparative example of the electric power generation components in 1st Embodiment The figure which shows the frequency characteristic of the conductance in the structure of the comparative example in 1st Embodiment The figure which shows the relationship between the conductance and the frequency in 1st Embodiment (A) Perspective view schematically showing the vibration of the first vibrating portion 103 and the second vibrating portion 104 (symmetric mode), (b) Cross-sectional view when viewing the xz plane (symmetric mode) (A) Perspective view schematically showing vibrations of the first vibrating portion 103 and the second vibrating portion 104 (oblique symmetry mode), (b) a cross-sectional view when viewing the xz plane (oblique symmetry mode) The figure which shows the electric power generation amount and frequency relationship of Embodiment 2. The figure which shows the change of the electric power generation characteristic when the space | interval in Embodiment 3 is changed. The figure which shows the relationship between the electric power generation amount and frequency at the time of changing the thickness of the 2nd structural member of the mechanical vibration propagation part in Embodiment 3. The figure which shows the relationship between the resonant frequency f1 of a symmetrical mode and the resonant frequency f2 of a diagonally symmetrical mode at the time of changing the thickness of the 2nd structural member of the mechanical vibration propagation part in Embodiment 3. Block diagram of a communication module using the power generator of the present invention Figure showing a conventional example Figure showing a conventional example

(Embodiment 1)
FIG. 1 is a top view of a power generation component 101 according to an embodiment of the present invention. The x, y, and z directions are defined in the figure. Hereinafter, the present invention follows this definition. 2 is a cross-sectional view taken along one-dot chain line AB in FIG. In FIG. 1 and FIG. 2, the first vibration unit 103 and the second vibration unit 104 are connected to and supported by the mechanical vibration propagation unit 102, and each vibration is transmitted through the mechanical vibration propagation unit 102. Propagates to each other's vibration part. In other words, the first vibration unit 103 and the second vibration unit 104 are mechanically coupled via the mechanical vibration propagation unit 102. Moreover, the 1st vibration part 103 and the 2nd vibration part 104 are the vibration parts of the cantilever structure which has the substantially same resonance frequency independently. The mechanical vibration propagation unit 102 corresponds to the portion in the region surrounded by the broken line 102 in FIGS. 1 and 2.

  The first vibrating portion 103 (corresponding to a portion surrounded by a broken line 103 in FIGS. 1 and 2) is a first lower surface electrode 113 provided above the first diaphragm 111, and a first lower surface electrode. The first piezoelectric portion 105 provided in contact with the upper surface of 113, the first upper surface electrode portion 107 provided in contact with the upper surface of the first piezoelectric portion 105, and provided below the first diaphragm 111. And a weight 119. The first upper surface electrode portion 107 provided in contact with the upper surface of the first piezoelectric portion 105 is connected to the 1a terminal electrode 115 through the extraction electrode. The first lower surface electrode 113 is electrically connected to the 1b terminal electrode 117.

  Further, the second vibrating portion 104 (corresponding to the portion surrounded by the broken line 104 in FIGS. 1 and 2) corresponds to the second lower surface electrode 114 provided above the second vibrating plate 112, and the second Provided below the second piezoelectric portion 106 provided in contact with the upper surface of the lower surface electrode 114, the second upper surface electrode portion 108 provided in contact with the upper surface of the second piezoelectric portion 106, and the second diaphragm 112. It is comprised from the weight 119 made. The second upper surface electrode portion 108 provided in contact with the upper surface of the second piezoelectric portion 106 is connected to the terminal electrode 116 of the second a through the extraction electrode, and provided in contact with the lower surface of the second piezoelectric portion 106. The second bottom electrode 114 thus formed is electrically connected to the second-b terminal electrode 118.

  Note that the weight 119 has a role of expanding inertial force due to environmental vibration, and by increasing its weight, the weight 119 can be configured to vibrate greatly with lower environmental vibration strength.

  In addition, the 1st electrode part as described in a claim is the electrode part of the 1st vibration part 103, and specifically points out the 1st lower surface electrode and the 1st upper surface electrode part. Similarly, the second electrode portion described in the claims refers to the electrode portion of the second vibrating portion 104, and specifically refers to the second lower surface electrode and the second upper surface electrode portion.

  Further, the mechanical vibration propagation unit 102 includes a first component member 109 (corresponding to a portion in a region surrounded by a broken line 109 in FIGS. 1 and 2) and a second component member 110. 2, the bottom of the second component 110 of the mechanical vibration propagation unit 102 (in the zx plane) is fixed to the base 149. In the case of a product, this foundation corresponds to, for example, a package. The base 149 is not shown in FIG. The first component member 109 is connected to the first vibration unit 103 and the second vibration unit 104, and the second component member 110 is directly or indirectly connected to the first component member 109. ing.

  Next, the configuration and materials in this embodiment will be described in more detail. The first diaphragm 111, the second diaphragm 112, the weight 119, and the portion below the first lower surface electrode 113 of the first constituent member 109 of the mechanical vibration propagation portion 102 are partially etched by silicon. By removing, it is comprised integrally. FIG. 3A shows a top view in which only the silicon portion is taken out, and FIG. 3B shows a cross-sectional view taken along one-dot chain line CD. In FIG. 3B, the hatched portion is the component part of the first vibration unit 103, and the wavy line part is the component part of the mechanical vibration propagation unit. When the z direction is the thickness direction, the thickness of the first diaphragm 111 is 100 μm, and the thickness of the weight 119 is 480 μm. The first lower surface electrode 113 disposed above the first diaphragm 111 is an electrode made of platinum, and is composed of a very thin layer of 1 μm or less.

  The first piezoelectric portion 105 is lead zirconate titanate (PZT), and is formed by sputtering or the like. The thickness is, for example, about several μm to 10 μm. FIG. 4 is a top view showing only the PZT portion. The broken line portion indicates the silicon portion shown in FIG.

  In FIG. 2, the thickness of the first component 109 of the mechanical vibration propagation unit 102 is roughly the connection of the first diaphragm 111 and the weight 119 of the first diaphragm 111 ignoring the thickness of the terminal electrode 1b. It is equal to the sum of the thickness of the silicon portion connected to the end portion on the non-side and the thickness of the first piezoelectric portion 105 (PZT), which is about 580 to 590 μm. Moreover, the 2nd structural member 110 of the mechanical vibration propagation part 102 is comprised with the glass epoxy, and the thickness is 0.5-several mm. The first constituent member 109 and the second constituent member 110 of the mechanical vibration propagation unit 102 are bonded with an adhesive, and in this embodiment, an epoxy material is used as the material. In addition, an acrylate-based material or a silicone-based material may be used.

  In the power generation component 101 described above, the first vibration unit 103 and the second vibration unit 104 vibrate due to environmental vibration, and electric charges are generated according to the stress generated in the first piezoelectric unit 105 and the second piezoelectric unit 106. The power generation operation will be performed. In addition, vibrations occur periodically, and positive and negative stresses are alternately generated, so that the positive and negative of the generated charges are also alternately switched, and as a result, power is generated as alternating current.

  Since general electronic devices use direct current as a power source, it is often necessary to convert alternating voltage (current) from piezoelectric components into direct current. The circuit is shown in FIG.

  In FIG. 5, a rectifier circuit 150 that converts alternating voltage (current) into direct current includes a full-wave rectifier circuit 120 in which diodes that output only a positive voltage are arranged in a ring shape, and smoothes the rectified signal to generate direct current. The capacitor 121 is used for output.

  In the present embodiment, the 1a terminal electrode 115 and the 2a terminal electrode 116 in FIG. 1 are electrically connected to the first input terminal 122 in FIG. 5, and the 1b terminal in FIG. The electrode 117 and the second-b terminal electrode 118 are electrically connected to the second input terminal 123 in FIG. As a result, the charges having the same phase generated by the first vibrating unit 103 and the second vibrating unit 104 can be combined and taken out as a direct current.

  FIG. 6 shows the relationship between the power generation amount and the frequency of the power generation device using the power generation component of the present embodiment. Here, the power generation device refers to a first electrode portion that contacts the first piezoelectric portion 105 (corresponding to the first upper surface electrode portion 107 and the first lower surface electrode 113) and a second electrode portion that contacts the second piezoelectric portion 106. A two-electrode portion (corresponding to the second upper surface electrode portion 108 and the second lower surface electrode 114) and a rectifier circuit 150 electrically connected to the first electrode portion and the second electrode portion as shown in FIG. I have it. In FIG. 6, the horizontal axis represents frequency, and the vertical axis represents the amount of power generation. As a comparative example for the power generation device of the present embodiment, the characteristics 124 of the power generation device configured to support a cantilever having the same structure as that of the first vibrating unit 103 shown in FIG. 7 are also shown in FIG. Yes. The characteristic 124 is obtained by doubling the power generation amount obtained from the power generation device using the power generation component having the structure shown in FIG. The cantilever 126 in FIG. 7 has the same structure as the first vibrating portion 103 (or the second vibrating portion 104), and is fixed to the base 127. The terminal electrode 128 and the terminal electrode 129 are connected to the upper surface electrode that is in contact with the upper surface of the diaphragm and the lower surface electrode that is in contact with the lower surface of the diaphragm, respectively, and similarly to the rectifier circuit shown in FIG. ing. Assuming that there are two power generation components, a value obtained by plotting the total power generation amount in FIG. Note that the measurement in FIG. 6 is performed by assuming the environmental vibration of a certain frequency and placing the power generation component 101 on the vibration exciter and forcibly applying the vibration of the assumed strength. The second vibration unit 104 is vibrated to measure the power generation amount. Moreover, the frequency characteristic is measured by changing the frequency to be excited.

  In FIG. 6, it can be seen that the characteristic 125 in the case of the power generation device according to the present embodiment has a wider frequency band with a high power generation amount in the power generation characteristic than the characteristic 124. If only Q of the power generation component is intentionally dropped with the same vibration, the peak value of the power generation amount will be greatly lowered. However, the characteristic 125 is that the power generation characteristic is generated while the peak value of the power generation amount is substantially maintained. A high frequency band is spreading. Thus, by adopting the structure of the present embodiment, it is possible to achieve a wide band while maintaining a large maximum power generation amount.

  Next, this reason will be described. FIG. 8 shows the frequency characteristics of conductance in the structure of the power generation component of the comparative example described in FIG. Conductance is a parameter indicating piezoelectric characteristics, and the characteristics are highly correlated with power generation characteristics. That is, in the portion where the conductance is high, the amount of power generation is also high, and the peak frequency and the peak frequency of the power generation amount are approximately close. In addition, when there are a plurality of resonances, the frequency positional relationship is generally close. In this embodiment, this conductance characteristic is used as one index for estimating the power generation performance. Here, for example, the measurement is performed by applying a sine wave voltage having an amplitude of ± 0.3 V to the component while sweeping the frequency. In vibration measurement using a vibrator or the like, it is not easy to measure by vibrating only one of a plurality of elements, for example, only the first vibration unit 103, as in the power generation component 101. However, measurement using such an electrical method can be easily performed. This means that the piezoelectric inverse effect that stress is generated when a voltage (or electric field) is applied is seen. Power generation uses the piezoelectric effect that voltage (or electric flux density) is generated when stress is applied, but the piezoelectric inverse effect and the piezoelectric effect are basically reversible. The power generation performance is estimated.

  FIG. 9 shows the relationship between conductance and frequency in this embodiment. A broken line 131 is a characteristic when the conductance of only the first vibration unit 103 is measured. This is because the conductance between the 1a terminal electrode 115 and the 1b terminal electrode 117 is measured, that is, a sine wave voltage is applied only between the electrodes, and only the first vibrating portion 103 is applied. This corresponds to a state in which environmental vibration is applied. Although a situation in which environmental vibration is applied only to one element cannot be expected in reality, this state is temporarily realized for identification of the vibration mode this time.

  A solid line 132 in FIG. 9 is a characteristic when both the first vibrating unit 103 and the second vibrating unit 104 are measured simultaneously. This is because the 1a terminal electrode 115 and the 2a terminal electrode 116 are short-circuited, the 1b terminal electrode 117 and the 2b terminal electrode 118 are short-circuited, and the 1a terminal electrode 115 and the 1b terminal electrode 117 are short-circuited. It is the state which is measuring between. This state corresponds to a state in which vibration is applied to both elements.

  When paying attention to the characteristic 131, there are three resonance peaks. If the peaks are the peaks 131a, 131b, and 131c in order from the lowest frequency, the peak 131c is the highest peak. This peak 131c substantially matches the resonance frequency when the first vibration unit 103 is present alone. This can be seen by comparison with the frequency characteristic of conductance shown in FIG. On the other hand, it has been found that 131a and 131b are vibrations that are generated when the first vibration unit 103 moves and the vibration propagates through the mechanical vibration propagation unit 102 and propagates to the second vibration unit 104. This is a conductance measurement corresponding to the measurement of the piezoelectric effect, and a vibration measurement (corresponding to the measurement of the piezoelectric inverse effect) in which the vibration state (displacement, speed, etc.) is directly measured while applying a voltage to the first vibration unit 103. It was found by using two measurement methods in combination.

  A perspective view schematically showing a vibration mode at a frequency of 131a is shown in FIG. In addition, FIG. 10B shows a cross-sectional view (when the y-axis is a normal line) when viewing the xz plane at that time. In the figure, the vibration amplitudes (displacements) of the first vibration unit 103 and the second vibration unit 104 are depicted in the same way, but actually, the vibration amplitude of the first vibration unit 103 to which a sine wave voltage is applied is illustrated. Is bigger. The vibration amplitude is measured and confirmed by measuring the speed with a laser Doppler vibrometer and calculating the displacement, that is, the vibration amplitude value from the result. This mode occurs when the first vibration unit 103 vibrates, so that the vibration propagates through the mechanical vibration propagation unit 102, is transmitted to the second vibration unit 104, and is vibrated. Although the vibration amplitude is different, the first vibration unit 103 and the second vibration unit 104 vibrate (displace) at the same phase. Note that the frequency of 131a is lower than the frequency of 131c because, from the viewpoint of the first vibration unit 103, the second vibration unit 104 that originally did not need to be moved is also coupled to the mechanical vibration propagation unit 102. Since it is necessary to move simultaneously, the frequency will drop. This is similar to the effect that the resonance frequency is lowered by adding the weight.

  Next, a sine wave voltage is applied to both the first vibrating portion 103 and the second vibrating portion 104 (the first a terminal electrode 115 and the second a terminal electrode 116 are short-circuited, and the first b terminal electrode 117 and the second b Terminal electrode 118 is short-circuited, and a sinusoidal voltage is applied between the first-a terminal electrode 115 and the first-b terminal electrode 117), and the first-a terminal electrode 115 and the first-b terminal in a state where they are excited. The result of measuring the conductance with the electrode 117 will be described. The result is the characteristic 132 of FIG. Here, the frequency to be excited was set to 132a, and the vibration amplitude value was measured with a laser Doppler vibrometer as described above. As a result, it was found that the first vibrating portion 103 and the second vibrating portion 104 were displaced at the same phase as shown in FIGS. 10 (a) and 10 (b). Here, since both the first vibration unit 103 and the second vibration unit 104 vibrate mainly, the vibration amplitudes are substantially the same. Here, the frequency of 131a and the frequency of 132a are close to each other.

  As described above, the resonance of the peak 132a is a vibration mode in which the vibration of the first vibration unit 103 and the vibration of the second vibration unit 104 vibrate in the same phase coupled via the mechanical vibration propagation unit 102. Hereinafter, this vibration mode is referred to as a symmetric mode. By using this symmetric mode, it is possible to configure a power generation component and a power generation device that widen a frequency band with a high power generation amount in the power generation characteristics without greatly reducing the peak value of the power generation amount at the resonance frequency. This is also clear from the results described in FIG. As described above, the power generation component of the present embodiment also has a wider range of frequencies (frequency) of the corresponding environmental vibrations.For example, when the frequency of environmental vibrations changes, a rapid decrease in the amount of power generation can be suppressed. Or, when there is broadband environmental vibration, a larger amount of power generation can be obtained.

  In addition, in the conventional configuration in which a wide band is obtained by arranging elements having different resonance frequencies, only a single element operates at a certain moment. Therefore, when trying to obtain a predetermined power generation amount, the size of the entire power generation component increases. End up. On the other hand, in the configuration of the present embodiment, the two vibrators (the first vibrating unit 103 and the second vibrating unit 104) vibrate simultaneously during the power generation operation, and the power generation amount is larger than that in the conventional configuration. As a result, the parts and the device can be downsized.

  Next, another peak 131b in the characteristic 132 in FIG. 9 will be described. Since the same method as the verification of the symmetry mode of the peak 131a is used for the verification of the peak, the details of the method are omitted. The peak of 131b is the same in that the first vibration unit 103 is coupled via the second vibration unit 104 and the mechanical vibration propagation unit 102, but the vibration phase is in an opposite phase and vibrates. Mode. FIG. 11A shows a schematic perspective view of vibration, and FIG. 11B shows a cross-sectional view of the xz plane. 11 (a) and 11 (b), as in FIGS. 10 (a) and 10 (b), the displacement of the first vibration unit 103 to which the sine wave voltage is originally applied is more sine wave voltage. Although it is larger than that of the second vibrating portion 104 that is not applied, it is described to the same extent so that the phenomenon becomes clear. Also here, the vibration of the first vibration unit 103 is coupled to the second vibration unit 104 via the mechanical vibration propagation unit 102 to cause the vibration of the second vibration unit 104, but unlike FIG. The vibration mode is such that the vibrations of the first vibration unit 103 and the second vibration unit 104 are vibrating in opposite phases. This mode is hereinafter referred to as an oblique symmetry mode. The peak 131b shows the resonance in the oblique symmetry mode. Since the peak 132b in the characteristic 132 of FIG. 9, which is a case where both the vibrating parts 103 and 104 are excited simultaneously, roughly matches the frequency of the peak 131b, the peak 132b is also in the oblique symmetry mode. I can say that.

  Note that a peak corresponding to the peak 131c in FIG. This means that the original single vibration is reduced by the coupling through the mechanical vibration propagation unit 102.

  In addition, since the oblique symmetry mode has an opposite phase, the charges cancel each other, and as a result, they disappear. This is why the power generation amount in 132b in FIG. 9 and the oblique symmetry mode in FIG. 6 is small. Since the amplitudes do not completely match, some peaks remain.

  In this embodiment, the power generator using the symmetric mode has been described. However, by changing the connection with the rectifier circuit 150, a configuration of the power generator using the oblique symmetric mode is also possible. For example, the 1a terminal electrode 115 and the 2b terminal electrode 118 of FIG. 1 are short-circuited and connected to the first input terminal 122, the 2a terminal electrode 116 and the 1b terminal electrode 117 are short-circuited, and What is necessary is just to connect to the 2nd input terminal 123. FIG. Whether to use the symmetric mode or the oblique symmetric mode may be determined in consideration of the frequency of the target environmental vibration.

  In the piezoelectric component described above, the first vibrating unit 103 and the second vibrating unit 104 vibrate simultaneously and contribute to power generation. Therefore, unlike the conventional example, a small and large power generation amount is obtained while achieving a wide band. be able to.

(Embodiment 2)
In the power generation component and the power generation device according to Embodiment 2 of the present invention, both the symmetric mode and the oblique symmetric mode are used to further widen the frequency band with high power generation amount in the power generation characteristics. Therefore, the configuration of the power generation component according to the second embodiment is the same as the configuration of the power generation component according to the first embodiment. However, in Embodiment 1, since only one rectifier circuit 150 shown in FIG. 5 is used, the generated charges in the reverse phase state (the reverse phase is the same phase) cancel each other. Therefore, the power generation apparatus according to Embodiment 2 prepares two rectifier circuits 150 shown in FIG. 5, and connects one rectifier circuit between the 1a terminal electrode 115 and the 1b terminal electrode 117. The other rectifier circuit is connected between the 2a terminal electrode 116 and the 2b terminal electrode 118 to solve this problem.

  FIG. 12 shows the relationship between the power generation amount and the frequency for the power generation device of the present embodiment. In FIG. 12, a characteristic 125 indicated by a broken line is a power generation characteristic of the characteristic 125 of FIG. 6 in which the symmetric mode described in the first embodiment is found. The characteristic 133 is a power generation characteristic of the power generator when both the symmetric mode shown in the present embodiment and the oblique symmetric mode are used. By using the oblique symmetric mode, the bandwidth can be further increased. Can do. Here, the power generation component operates in the symmetric mode near the frequency f1, and operates in the oblique symmetric mode near f2, but both the first vibration unit 103 and the second vibration unit 104 always vibrate and generate power. It contributes to.

  In general, when a single element is designed to generate a plurality of modes, higher-order vibrations in a mode having a frequency lower than the main resonance frequency are often used. For example, in the case of thickness-type vibrators such as thickness shear vibration and thickness longitudinal vibration, the higher-order modes of lower-frequency vibration modes such as contour vibration and width vibration are brought close to the main resonance to increase the bandwidth. It may be planned. In the case of a power generation component, since the stress applied to the component has a correlation with the amount of power generation, flexural vibration with a large displacement is often set as the main mode. Bending vibration is the lowest vibration mode among the various vibration modes, and the method described above cannot be used. Therefore, the new method of combining the two vibration parts as in the present embodiment to widen the band is a very effective method particularly when bending vibration is used.

  In addition, the power generation element according to the first embodiment is also effective in bending vibration with strong vibration strength because the first vibration unit 103 and the second vibration unit 104 can be strongly coupled via the mechanical vibration propagation unit 102. .

(Embodiment 3)
The power generation component and the power generation device according to Embodiment 3 of the present invention change the degree of coupling between the first vibration unit 103 and the second vibration unit 104 of the power generation component or power generation device in the first and second embodiments. In this configuration, the frequency band with high power generation in the power generation characteristics of the piezoelectric component can be changed. When the degree of coupling, which is the degree of coupling, is increased, the vibration of the first vibration unit 103 is more easily transmitted to the second vibration unit 104 (and vice versa), and the frequency band with high power generation in the power generation characteristics of the power generation component is widened. It will be. The basic structure of the power generation component and power generation device according to the third embodiment is the same as that of the power generation component and power generation device of the first and second embodiments, and is shown in FIGS. A description will be given based on power generation components.

  In order to change the degree of coupling, first, the arrangement interval between the first vibrating unit 103 and the second vibrating unit 104 can be changed. In the present invention, the “arrangement distance between the first vibration unit and the second vibration unit” refers to the end of the first vibration unit 103 (for example, the portion connected to the mechanical vibration propagation unit 102 of the first vibration unit 103) and the first vibration unit 103. The distance (for example, the 1st vibration part 103 and the 2nd vibration part 104 in the mechanical vibration propagation part 102) of the edge part (For example, site | part connected with the mechanical vibration propagation part 102 of the 2nd vibration part 104) of the 2 vibration part 104 Space between the part other than the end part of the first vibration part 103 and the part other than the end part of the second vibration part 104 (for example, the space between the first vibration part 103 and the second vibration part 104). (Distance between the closest parts). This is because the gas filled around the first vibrating portion 103 and the second vibrating portion 104 is coupled to each other even when used as a medium.

  As an example, FIG. 13 shows an interval between the first vibration unit 103 and the second vibration unit 104 in the mechanical vibration propagation unit 102 (the end of the first vibration unit 103 on the mechanical vibration propagation unit 102 side and the second vibration unit 104. The state of power generation characteristics when the distance from the end on the mechanical vibration propagation unit 102 side is changed from 1.2 mm (characteristic 134 in FIG. 13) to 0.3 mm (characteristic 135 in FIG. 13). Show. This is because the interval between these portions has the greatest influence on the degree of coupling. By reducing this interval, the degree of coupling increases, and the frequency band in which the power generation amount of the power generation characteristics shown in FIG. As can be seen from FIG. 13, when the interval between the first vibration unit 103 and the second vibration unit 104 in the mechanical vibration propagation unit 102 is narrowed, the resonance frequency decreases in both the symmetric mode and the oblique symmetric mode. Since the degree of reduction is large, the frequency band with high power generation amount in the power generation characteristics is widened.

  Note that other intervals such as the tip portions of the first vibrating portion 103 and the second vibrating portion 104 may also affect the degree of coupling. For example, when a power generation component is put in a package and hermetically sealed with nitrogen or the like, when the vibrating parts 103 and 104 are displaced, the vibrating parts 103 and 104 are affected by the fluid effect of the gas around the vibrating parts 103 and 104. May bind to each other. This is because the space around the vibrating parts 103 and 104 is small or the molecular weight of the gas is large, so that the degree of coupling is further increased. In such a case, the coupling degree can be changed by changing the distance between the weight at the tip of the first vibrating part 103 and the weight at the tip of the second vibrating part 104 that has a large vibration width and a large thickness. May be. This is because this part has a large vibration width and a large thickness, and thus has a large influence on the surrounding space.

  As described above, the power generation component and the power generation apparatus according to the third embodiment can be easily obtained by adopting the power generation component design method that adjusts the arrangement interval between the first vibration unit 103 and the second vibration unit 104. Power generation characteristics can be realized and manufacturing efficiency can be improved. As a specific method of adjusting the arrangement interval between the first vibrating unit 103 and the second vibrating unit 104, at least a part of at least one of the first vibrating unit 103 and the second vibrating unit 104 may be laser ablated or dried. A method of removing by etching or the like, a method of removing a part of the mechanical vibration propagation unit 102 connecting the first vibration unit 103 and the second vibration unit 104 by the same method, and the like are conceivable.

  As a second method of changing the degree of coupling between the first vibrating unit 103 and the second vibrating unit 104, elasticity which is a material constant of the first component member 109 and the second component member 110 of the mechanical vibration propagation unit 102 is used. A method of changing the rate is mentioned. For example, when the second constituent member 110 of the mechanical vibration propagation unit 102 is made of silicon having a large elastic modulus, the coupling becomes very small, and in particular, the oblique symmetry mode is hardly observed. On the other hand, when the second constituent member 110 is realized by the glass epoxy having a lower elastic modulus than the silicon constituting the first constituent member 109, even at the frequency of f2 oscillating in the oblique symmetry mode as shown by the characteristic 133 in FIG. High power generation can be obtained. Therefore, the second component member 110 is preferably made of a material having a smaller elastic modulus than the first component member 109 of the mechanical vibration propagation unit 102. For example, as the second component 110 of the mechanical vibration propagation unit 102, a large coupling between the first vibration unit 103 and the second vibration unit 104 can be obtained by using a resin having a low elastic modulus as a main material. .

  For the purpose of reducing the size of the power generation component of the present invention, the first component member 109 of the mechanical vibration propagating portion 102 is directly fixed to a hard package such as ceramic disposed around the power generation component. The adhesive used may be substituted for the second component 110 of the mechanical vibration propagation unit 102. In this case, the bond can be increased by reducing the elastic modulus of the adhesive or increasing the thickness. As the adhesive, a silicone-based or epoxy-based adhesive is preferable. Moreover, since the variation in the thickness of the adhesive leads to a variation in the degree of coupling, and as a result, the variation in the frequency band in which the amount of power generation of the power generation characteristics is high, it is preferable to pay attention to the thickness accuracy. Therefore, the application amount of the adhesive is more preferably controlled by a dispenser or the like when a liquid adhesive is used. Further, the thickness may be controlled by a sheet adhesive or the like. Thereby, the dispersion | variation in the thickness of an adhesive agent can be suppressed. The sheet adhesive may be cut and affixed to a predetermined dimension in a semi-cured state, or pasted on the base by a method such as laminating in a large format, and pressed the power generation component 101 from above. Then, it may be adhered. At this time, after bonding in a large format, the device can be efficiently manufactured by cutting into individual parts by dicing.

  When the first constituent member 109 of the mechanical vibration propagating portion 102 is made of a material having a low elastic modulus such as a resin, the first constituent member 109 is elastic in the vicinity of the connecting portion (supporting portion) between the first constituent member 109 and the first vibrating portion 103. Loss increases and the peak value of power generation itself decreases. Therefore, the first constituent member 109 of the mechanical vibration propagation portion 102 is preferably made of a material having a large elastic modulus, and the second constituent member 110 of the mechanical vibration propagation portion 102 fixed to the base 149 is made of a material having a smaller elastic modulus. Is preferred. By selecting such an elastic modulus, it is possible to suppress the elastic loss while increasing the degree of coupling between the first vibrating unit 103 and the second vibrating unit 104.

  The second component member 110 of the mechanical vibration propagation unit 102 does not need to be directly fixed to the base 149, and may be indirectly fixed via another material. In short, it may be arranged at a position closer to the fixed portion than the first component member 109 of the mechanical vibration propagation portion. In addition, when the first vibration part 103 is fixed to the first constituent member 109 of the mechanical vibration propagation part 102 with an adhesive or the like and connected and supported, the thickness of the adhesive layer is preferably thin. This is to keep the elastic loss low. Further, the elastic modulus of the adhesive is preferably larger than that of the second component 110, and for example, an acrylate-based or epoxy-based adhesive is preferable.

  As described above, the power generation component according to the third embodiment is adopted by adopting the power generation component design method that adjusts the elastic modulus that is the material constant of the first structural member 109 and the second structural member 110 of the mechanical vibration propagation unit 102. The components and the power generation device can easily achieve desired power generation characteristics and improve manufacturing efficiency.

  As a third method of changing the degree of coupling between the first vibration unit 103 and the second vibration unit 104, changing the thickness of the second component member 110 of the mechanical vibration propagation unit 102. FIG. 14 shows power generation characteristics (relationship between power generation amount and frequency) when the thickness is changed. A characteristic 136 is a characteristic when the thickness of the second component 110 of the mechanical vibration propagation unit 102 is 0.3 mm, and a characteristic 137 is a characteristic when the thickness is 1 mm. Although the resonance frequency of the oblique symmetry mode does not change so much, the resonance frequency of the symmetry mode is greatly changed. As a result, a frequency band having a high power generation amount in the power generation characteristics is widened.

  FIG. 15 shows the resonance frequency f1 in the symmetric mode and the resonance frequency f2 in the oblique symmetry mode when the thickness of the second component member 110 of the mechanical vibration propagation unit 102 is changed. As can be seen from FIG. 15, as the thickness of the second component member 110 increases, f1 tends to decrease. Although f2 also decreases slightly, it is a very small change compared to f1.

  As described above, the power generation component and the power generation apparatus according to Embodiment 3 can easily achieve desired power generation characteristics by adopting the power generation component design method that adjusts the thickness of the second component 110 of the mechanical vibration propagation unit 102. And manufacturing efficiency can be improved.

  With the method described above, it is possible to adjust the frequency band where the power generation amount is high in the power generation characteristics of the power generation component by changing the degree of coupling between the vibration parts.

(Embodiment 4)
A communication module using the power generator of the present invention according to Embodiment 4 is shown in FIG. A communication module 147 attached to a product being manufactured and used for product management in the factory includes a robot 148 in the factory, a data management server (not shown) arranged in the factory, and a management device (not shown) operated by a person. None) and a terminal (not shown). Thereby, it is possible to monitor the state of the product to which the communication module 147 is attached or to manage in real time.

  The communication module 147 includes the power generation device 138 shown in the first embodiment or the second embodiment (specifically, a broadband power generation device using both the symmetric mode and the oblique symmetric mode), the power generation device 138, It has a DC-DC converter 139 that is electrically connected, and a wireless terminal 140 that is electrically connected to the DC-DC converter 139.

  The DC-DC converter 139 is a circuit that boosts or lowers the direct current output from the power generation device 138 to the level of the power supply voltage of the wireless terminal 140. The wireless terminal 140 is electrically connected to the communication unit 141 including the transmission unit 142, the reception unit 143, and the antenna 146, the signal processing unit 144 electrically connected to the communication unit 141, and the signal processing unit 144. And a memory 145. The communication unit 141 is a functional block that transmits and receives data to and from the robot 148 and the like. The signal processing unit 144 processes the data received from the receiving unit 143 and stores the data in the memory 145 or takes out data to be transmitted to the robot 148 from the memory 145 and outputs the data to the transmitting unit 142.

  Products are usually placed in fixed equipment such as conveyors, and the environmental vibrations obtained from them are fixed. Therefore, it is only necessary to design power generation components according to this frequency (frequency). . However, the vibration source is often mechanical vibration of equipment, and the frequency deviation is often about ± 1 to 3%. For example, when a power generation component having a single resonance frequency as in the comparative example described with reference to FIG. 7 is used, the resonance frequency is shifted by 1%, so that the power generation amount is 10% or less compared to when the power generation amount is maximum. It may fall down. Since the power generation component of the present invention has a wide frequency band where the power generation amount is high, if the frequency deviation of the vibration source is a deviation of about 1%, the power generation amount is within 90% even when compared to the maximum. become. Further, by using the wideband method as described in the second and third embodiments, if the frequency deviation of the vibration source is in the range of about ± 3%, power generation can be performed to a level of 80% or more by comparing the maximum value of power generation. The amount can be maintained.

  As described above, the communication module 147 provided with the power generation device 138 described in this embodiment can realize a self-supporting module that generates power and supplies power without itself having a battery. . The effect of the present invention is particularly great when the frequency is determined, such as vibration of equipment, and the frequency deviation is about several percent.

  In this embodiment, the battery is used as a structure that does not have a battery completely. However, a secondary battery may be provided, and the battery may be charged and used when necessary. Thereby, since the electric power when not in use can be stored, it is possible to cope with the case where the power consumption when the module is used is large. This is because a general communication module rarely communicates constantly and often communicates intermittently. Further, when the power consumption of the communication module 147 may be low, the power generation component may be made smaller by that amount (particularly, the first vibration unit 103 and the second vibration unit 104).

  The power generation component and the power generation apparatus according to Embodiments 1 to 4 described above can achieve a wide band of power generation characteristics by simultaneously vibrating the first vibration unit 103 and the second vibration unit 104, and are compact. Power generation parts and power generation devices can be realized. As a result, downsizing of the self-supporting communication module can be realized.

  In the first to fourth embodiments, the configuration having two vibration parts has been described. However, two or more vibration parts may be provided. In that case, a plurality of combinations of the oblique symmetry modes are provided, and a further broadening of the bandwidth can be achieved.

  In the first to fourth embodiments, the resonance frequencies when the two vibrating parts move completely independently are made the same, but they need not be completely the same. Note that the resonance frequency of one vibration part may be designed to be between the resonance frequency and the anti-resonance frequency of another vibration part. This is because the amount of power generation decreases at the anti-resonance frequency. For example, when the resonance frequency of one vibration part becomes close to the anti-resonance frequency of the other vibration part, the amount of power generation near one resonance frequency is drastically reduced due to the influence of the other anti-resonance.

  In the first to fourth embodiments, the bottom surface (the surface parallel to the zx plane) of the first component member 109 of the mechanical vibration propagation unit 102 is in contact with the second component member 110 of the mechanical vibration propagation unit 102. However, the same effect can be obtained even if the side surface (the surface parallel to the yz plane) of the first component member 109 is in contact with the second component member 110 of the mechanical vibration propagation unit 102. In this case, it may be fixed to the base 149 on the bottom surface of the second component member 110 of the mechanical vibration propagation unit 102, or may be fixed to the side surface of the second component member 110. Further, the second component member 110 may be directly connected to the first component member 109, or may be indirectly connected via another member. In either case, the power generation component of the present invention described in the first to fourth embodiments has the effect.

  In the above description, the first upper surface electrode portion 107 and the first lower surface electrode 113 are disposed in contact with the upper surface and the lower surface of the first piezoelectric portion 105, respectively. The first upper surface electrode portion 107 may be disposed, and the first lower surface electrode 113 may be disposed below the first piezoelectric portion 105. Similarly, in the above description, the second upper surface electrode portion 108 and the second lower surface electrode 114 are disposed in contact with the upper surface and the lower surface of the second piezoelectric portion 106, respectively, but above the second piezoelectric portion 106. The second upper surface electrode portion 108 may be disposed, and the second lower surface electrode 114 may be disposed below the second piezoelectric portion 106. Even in such a configuration, the same effect as described above can be obtained.

  As described above, the power generation component of the present invention and a power generation apparatus using the power generation component can provide a small self-supporting power source, eliminate the need for batteries for electronic devices such as sensor network terminals, and generate 2 By charging the secondary battery, battery replacement can be made unnecessary. Therefore, a maintenance-free electronic device can be realized.

DESCRIPTION OF SYMBOLS 101 Power generation component 102 Mechanical vibration propagation part 103 1st vibration part 104 2nd vibration part 105 1st piezoelectric part 106 2nd piezoelectric part 107 1st upper surface electrode part 108 2nd upper surface electrode part 109 1st structural member of a mechanical vibration propagation part DESCRIPTION OF SYMBOLS 110 2nd structural member of mechanical vibration propagation part 111 1st diaphragm 112 2nd diaphragm 113 1st lower surface electrode 114 2nd lower surface electrode 115 1a terminal electrode 116 2a terminal electrode 117 1b terminal electrode 118 1st 2b terminal electrode 119 weight 120 full wave rectifier circuit 121 capacitor 126 cantilever 150 rectifier circuit

Claims (9)

A machine vibration propagation unit for propagating machine vibrations;
A first vibration part connected to the mechanical vibration propagation part and a second vibration part connected to the mechanical vibration propagation part,
The first vibration part has a first piezoelectric part,
The second vibrating part has a second piezoelectric part,
A power generation component that vibrates in a symmetric mode by coupling the first vibration part and the second vibration part via the mechanical vibration propagation part. A machine vibration propagation unit for propagating machine vibrations;
A first vibration part connected to the mechanical vibration propagation part and a second vibration part connected to the mechanical vibration propagation part,
The first vibration part has a first piezoelectric part,
The second vibrating part has a second piezoelectric part,
A power generation component that vibrates in an obliquely symmetric mode by coupling the first vibrating section and the second vibrating section via the mechanical vibration propagation section. A machine vibration propagation unit for propagating machine vibrations;
A first vibration part connected to the mechanical vibration propagation part and a second vibration part connected to the mechanical vibration propagation part,
The first vibration part has a first piezoelectric part,
The second vibrating part has a second piezoelectric part,
A power generation component that vibrates in a symmetric mode and a diagonally symmetric mode by coupling the first vibration part and the second vibration part via the mechanical vibration propagation part. The power generation component according to claim 1 or 2,
A first electrode portion in contact with the first piezoelectric portion;
A second electrode portion in contact with the second piezoelectric portion;
And a first rectifier circuit electrically connected to the first electrode portion and the second electrode portion. The power generation component according to claim 1, claim 2, or claim 3,
A first electrode portion in contact with the first piezoelectric portion;
A second electrode portion in contact with the second piezoelectric portion;
A first rectifier circuit electrically connected to the first electrode portion;
And a second rectifier circuit electrically connected to the second electrode portion. 4. The power generation component according to claim 1, wherein vibrations of the first vibration part and the second vibration part are bending vibrations. A machine vibration propagation unit for propagating machine vibrations;
A first vibration part connected to the mechanical vibration propagation part and a second vibration part connected to the mechanical vibration propagation part,
The first vibration part has a first piezoelectric part,
The second vibrating part has a second piezoelectric part,
In the power generator that vibrates in at least one of a symmetric mode and an oblique symmetric mode by coupling the first vibration unit and the second vibration unit via the mechanical vibration propagation unit,
The first vibration portion and the second vibration are changed by changing an arrangement interval between the first vibration portion and the second vibration portion, an elastic modulus of the mechanical vibration propagation portion, or a thickness of the mechanical vibration propagation portion. Power generation component that adjusts the degree of coupling of parts. The mechanical vibration propagation part is composed of a first component member and a second component member which are at least two types of members,
The first component member is connected to the first vibrating part and the second vibrating part,
The second component member is directly or indirectly connected to the first component member,
The power generation component according to claim 1, wherein the elastic modulus of the second component member is smaller than the elastic modulus of the first component member. The power generation device according to claim 4 or 5,
A communication module having a wireless terminal electrically connected to the power generation device.

Images