JP4533095B2 - Voltage conversion element and device using the element - Google Patents

Description

  The present invention relates to a voltage conversion element and an apparatus using the element.

  A device including a piezoelectric member using a piezoelectric effect that generates a voltage when strain is applied includes circuit elements such as an oscillator, an actuator, a speaker, and a sensor, and these are used in an integrated circuit (IC).

  The oscillator includes a crystal oscillator and a ceramic oscillator. An oscillator using a piezoelectric member combined with an active element is often used as an oscillation circuit for an operation clock in an integrated circuit (for example, see Patent Document 1). ).

  A speaker is an element that directly converts vibration into sound by using distortion of a piezoelectric member when a voltage is applied, and is used for a buzzer, a small speaker, and the like (for example, see Patent Document 2).

  Actuators that use the vibration energy of large vibrations generated by resonating an elastic body using a piezoelectric member as an excitation source (see, for example, Patent Document 3), or piezoelectric members that are stacked and large at low voltage A non-resonant type capable of obtaining distortion has been put into practical use (see, for example, Patent Document 4).

  Fine circuit elements used in ICs include transistors that control a large output current with a small current and FETs (Field Effect Transistors) that control an output current with a voltage. These are used as inverting amplification elements. ing.

  In addition, it is also used as a sensor for measuring various physical quantities by taking out a strain physically applied to the piezoelectric member as a voltage output corresponding to the piezoelectric effect (see, for example, Patent Document 5).

  By the way, recently, in the field of piezoelectric members, it has been studied to generate reversible giant electrostriction using the property of symmetry of the nanoorder of point defects (for example, see Non-Patent Document 1).

  When an electric field is applied to a piezoelectric material having domains (regions) with different electric polarization directions, domain transformation occurs so that the polarization direction follows the voltage direction, and the major axis direction and minor axis direction of the ferroelectric phase having low symmetry are Will be exchanged. The magnitude of the strain obtained at this time is the difference between the major axis and the minor axis, which is several tens of times larger than the normal piezoelectric effect.

  The occupancy of other point defects around a point defect (in the nanometer range) matches the crystal symmetry at equilibrium, and the point defect symmetry in the paraelectric phase is high, while the point defect in the ferroelectric phase is high. Symmetry is low, as is crystal symmetry. Further, the polarization of point defects due to the point defects in the ferroelectric phase also coincides with the spontaneous polarization.

  When this is utilized to cool the paraelectric phase piezoelectric material to the ferroelectric state, the piezoelectric material becomes unstable because it inherits the symmetry of the point defect and that of the paraelectric phase. The point defect symmetry of each domain is stabilized in accordance with the crystal symmetry of the domain by the diffusion of the point defect with aging. When an electric field is applied to the piezoelectric material in this state, the domain conversion described above occurs, and when the electric field is removed, the original domain state is restored.

According to the point defect electrostrictive material having such a configuration, for example, a high-performance piezoelectric material that obtains a large electrostrictive effect of 40 times at a low voltage as compared with the electrostrictive effect of a piezoelectric element made of lead zirconate titanate material is obtained. be able to.
Japanese Patent Laid-Open No. 08-130437 JP-A-10-277484 Japanese Patent Laid-Open No. 11-215861 JP 2004-048984 A JP 2002-107374 A Xiaobing Ren, “Large electric-field-induced strain in ferroelectric crystals by point-defect-mediated reversible domain switching”, Nature Materials, Nature Publishing Group, February 1, 2004, Volume 3, p. 91-94 and [online], January 11, 2004, Internet <URL: www.nature.com/naturematerials>

  However, an oscillator including the above-described piezoelectric member requires an active element for oscillating the resonator, which complicates the configuration of the integrated circuit.

  Moreover, in order to vibrate a speaker, an actuator, etc., it is necessary to use an AC voltage generating element that generates an AC voltage supplied to the piezoelectric member, or to form a self-excited oscillation circuit, and the configuration of the integrated circuit is complicated. To do.

  Since the inverting amplification element outputs a current, not only a resistor is required to convert this into a voltage, but also a non-inverting amplification circuit needs to be connected in two stages in series. Therefore, the configuration of the integrated circuit becomes complicated.

  The sensor can extract the generated distortion as a voltage output corresponding to the piezoelectric effect. However, when the distortion disappears, the voltage returns to 0, so that a single phenomenon such as occurrence of a small distortion is detected. Is difficult. Therefore, in order to detect such a single phenomenon, it is necessary to always monitor or always record all output signals, so usability is low.

  An object of the present invention is to provide a voltage conversion element capable of simplifying the configuration of a circuit element and an apparatus using the element.

In order to achieve the above object, the present invention provides a voltage conversion element including first and second energy conversion elements having different ratios of change in distortion amount to change in applied voltage, wherein the first energy conversion element is the first energy conversion element. The device is connected to a first terminal, the second energy conversion device is connected to a second terminal different from the first terminal, and the first energy conversion device and the second energy conversion device are connected. The elements are arranged adjacent to each other, and the ratio of the change in the distortion amount with respect to the change in the applied voltage in the second energy conversion element is the distortion amount with respect to the change in the applied voltage in the first energy conversion element. less than the ratio of the change, the second energy conversion element generates a distortion subject to a distortion caused by said first energy conversion element, the second energy Voltage generated in the second terminal by the conversion element distorted, there is provided a voltage conversion device characterized by greater than the voltage inputted to the first terminal.

  Moreover, the apparatus using said voltage conversion element is provided.

  According to the voltage conversion element of the present invention, the first section has a distortion characteristic that sharply increases when the voltage value exceeds a predetermined value, and substantially has a distortion characteristic when the voltage value is zero. Therefore, digital voltage conversion is possible, and various logic devices that directly convert voltage to voltage with one voltage conversion element can be configured, and the circuit configuration can be simplified. In addition, by configuring the distortion characteristics to be controllable according to the voltage value, it is possible to provide an apparatus using a voltage conversion element useful for a sensor with high usability.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram schematically showing a configuration of a voltage conversion element according to the first embodiment of the present invention.

  In FIG. 1, a voltage conversion element 100 according to the present embodiment includes an antiferroelectric piezoelectric member 1 constituting a first section, a ferroelectric piezoelectric member 2 constituting a second section, An electrode 3 as a first terminal connected to the ferroelectric piezoelectric member 1, an electrode 4 connected to the joint of the antiferroelectric piezoelectric member 1 and the ferroelectric piezoelectric member 2, and ferroelectric And an electrode 5 as a second terminal connected to the piezoelectric member 2.

  The piezoelectric member 1 and the piezoelectric member 2 are made of a plate-like body or a film-like body and are arranged so as to overlap each other in a layered manner, and constitute a piezoelectric body utilizing the piezoelectric effect. The antiferroelectric piezoelectric member 1 has a characteristic of extending in the direction in which a voltage is applied regardless of the polarity of the applied voltage.

  FIG. 2 is a diagram schematically showing the amount of strain (amount of strain) with respect to the electric field strength of the piezoelectric material, which is schematically represented with reference to the characteristics of the high-performance piezoelectric material of Non-Patent Document 1 above. A change in the amount of distortion is represented by setting the amount to zero. The solid line shows the characteristics of piezoelectric materials that generate reversible giant electrostriction using the property of symmetry of the nano-order of point defects, and the dotted line shows the characteristics of ferroelectric piezoelectric materials such as piezos. Yes.

  The characteristics shown by the solid line in FIG. 2 indicate that the distortion is very large. However, the distortion suddenly increases when the electric field strength exceeds a certain level, and when the electric field strength is reduced to 0, the distortion returns to the original state. In addition, it has characteristics such as having a large hysteresis, and is characteristically similar to the characteristics of an antiferroelectric piezoelectric material.

In the following description, electrical with such properties - but be described the antiferroelectric piezoelectric member as an example of mechanical energy conversion element, an electric characteristic as shown by the solid line in FIG. 2 - in mechanical energy conversion element If it exists, it is not restricted to an antiferroelectric piezoelectric member. Similarly machine - electric and energy conversion element will be described as an example ferroelectric piezoelectric member, but mechanical properties such as shown by dotted lines in FIG. 2 - in case if a ferroelectric electric energy conversion element piezoelectric It is not limited to members.

  The antiferroelectric piezoelectric member 1 having the hysteresis characteristic shown by the solid line in FIG. 2 has a distortion characteristic that the distortion sharply increases when the electric field strength increases to a predetermined value, for example, 20 kV / mm or more, and the electric field strength. When 0 becomes 0, some distortion may actually remain, but it becomes substantially 0 (in other words, almost the same amount of distortion is obtained each time the electric field intensity is 0). Further, the antiferroelectric piezoelectric member 1 has a large hysteresis characteristic as shown in FIG. The ferroelectric piezoelectric member 2 has the property that the amount of strain is proportional to the electric field strength, and also has the property of generating a charge proportional to the strain.

  According to the voltage conversion element 100 of FIG. 1, a large distortion is generated by applying a saturation voltage to the antiferroelectric piezoelectric member 1, and accordingly, a piezoelectric adjacent to the antiferroelectric piezoelectric member 1 is generated. A large distortion is generated in the member 2 and the piezoelectric member 2 outputs a voltage corresponding to the distortion to the electrode 5 due to the piezoelectric effect. Therefore, with a simple circuit configuration, the thickness of each piezoelectric member, the number of stacked layers, the electrode area, etc. A high voltage can be extracted by amplifying the applied voltage with a corresponding amplification factor. Further, it is possible to directly convert voltage to voltage without converting current to voltage.

  FIG. 3 is a circuit diagram showing a configuration of an amplifying element as a voltage conversion element according to the second embodiment of the present invention, and FIG. 4 is a diagram showing signal waveforms of respective parts of the amplifying element in FIG. .

  Since the amplification element as the voltage conversion element according to the present embodiment has the same configuration as that of the voltage conversion element 100 of FIG. 1, the same reference numerals are given to the same configuration and elements, and the description thereof is omitted.

  In FIG. 3, the antiferroelectric piezoelectric member 1 generates substantially the same strain regardless of whether the polarity of the input voltage Vin is positive or negative. As the antiferroelectric piezoelectric member 2, it is preferable to use a piezoelectric member that generates a large strain with a small electric field strength. An input signal Vin having a substantially triangular wave (FIG. 4) is input to the electrode 3. The electrode 4 is connected to ground and defines a reference voltage of 0V. From the electrode 5, an amplified output voltage Vout having a substantially rectangular waveform (FIG. 4) is output.

  The waveform of the output voltage Vout is affected by the hysteresis of distortion shown by the solid line in FIG. 2 of the antiferroelectric piezoelectric member 1, and specifically, the piezoelectric member 1 until the input voltage Vin reaches a predetermined value. This is influenced by the hysteresis that the piezoelectric member 1 is abruptly distorted when it exceeds a predetermined value, and that the distortion of the piezoelectric member 1 is abruptly released when the input voltage is close to zero.

  Further, by using an antiferroelectric piezoelectric member 2 that generates a large strain with a small electric field strength, an amplification element 300 having a large amplification factor can be configured. Since it has such hysteresis, generation of noise can be suppressed.

  The antiferroelectric piezoelectric member 1 generates substantially the same distortion regardless of whether the input voltage Vin is positive or negative. Therefore, in order to amplify the AC signal in the amplifying element 300, it is necessary to apply an offset voltage. .

  In the present embodiment, the polarization direction of the piezoelectric member 2 may be switched. Thereby, an amplifying element having a reverse polarity can be configured easily.

  Further, by not using the hysteresis region of the piezoelectric member 1, the amplifying element 300 may be used as an analog amplifier.

  Furthermore, in this embodiment, the input voltage Vin is applied to the electrode 3 and the electrode 4 is used as the reference voltage. However, the input voltage Vin may be applied to the electrode 4 and the electrode 3 may be used as the reference voltage. In this case, the input voltage Vin is superimposed on the output voltage to the electrode 5.

  FIG. 5 is a circuit diagram schematically showing a configuration of a modification of the amplifying element 300 of FIG.

  An amplifying element as a modification of the amplifying element 300 in FIG. 3 is an element in which the input and output of the amplifying element 300 in FIG. 3 are insulated. Those descriptions are omitted.

  In FIG. 5, the amplifying element 500 includes an insulating member 7 that electrically insulates between the piezoelectric member 1 and the piezoelectric member 2, and an electrode 6 that is connected to a joint between the insulating member 7 and the piezoelectric member 2. . The electrode 4 is connected to a joint between the insulating member 7 and the piezoelectric member 2 and is connected to the ground, and defines a reference potential of 0V. The electrode 6 is connected to another ground (not shown) that defines a reference potential of 0V.

  Since the amplifying element 500 is electrically insulated between the piezoelectric member 1 and the piezoelectric member 2 by the insulating member 7, it is possible to transmit signals by providing different reference voltages between the piezoelectric member 1 and the piezoelectric member 2. . Thereby, for example, the electrode 4 is connected to a ground (not shown) and the electrode 6 is connected to a predetermined DC voltage source (not shown) to be used as an insulating buffer element or an inverting element that transmits a signal between different reference voltages. can do. Such an element can be used as, for example, a known high-side N-channel MOSFET driver (high-side driver) used when an N-channel MOSFET is used on the high-side (power supply side) of the bridge circuit. Usually, such a high-side driver requires a complicated circuit such as a charge pump circuit, but if this device is used, it can be realized by one element.

  FIG. 6 is a circuit diagram schematically showing a configuration of an oscillation element as a device using the voltage conversion element according to the third embodiment of the present invention.

  In the oscillation element using the voltage conversion element according to the present embodiment, the same components and elements as those of the voltage conversion element 100 are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 6, an oscillation element 600 is configured such that the output voltage of the non-inverting amplification element is positively fed back, and the antiferroelectric piezoelectric member 8 having hysteresis characteristics shown by the solid line in FIG. A ferroelectric piezoelectric member 9, an electrode 10 connected to a joint provided between the piezoelectric member 8 and the piezoelectric member 9, an electrode 11 connected to the piezoelectric member 9, an electrode 10, and an electrode 4 And the resistor 12 connected to the output terminal and connected to the ground, the electrode 3 connected to the joint provided between the piezoelectric member 1 and the piezoelectric member 8, and the ground connected to the electrode 3. And a disposed resistor 13. The electrode 3 is connected to a DC power source (not shown). The electrode 11 is connected to a ground that defines a reference potential. The distortion characteristics with respect to the electric field strength of the piezoelectric member 8 are the same as those indicated by the solid line in FIG. 2, and the distortion characteristics with respect to the electric field strength of the piezoelectric member 9 are the same as those indicated by the dotted line in FIG.

  In FIG. 6, the power supply voltage Vcc applied from the DC power supply to the oscillation element 600 is input as the voltage V3 through the electrode 3 and extracted as the output voltage Vout. The piezoelectric member 2 and the piezoelectric member 9 are configured to generate a voltage having the same polarity as the power supply voltage Vcc.

  According to the oscillation element 600 of FIG. 6, it can oscillate only by applying a DC voltage.

  FIG. 7 is a diagram showing voltage waveforms of the electrodes in the oscillation element 600 of FIG.

  As shown in FIG. 7, when the power supply voltage Vcc from the power supply is not applied to the oscillation element 600, the potential V3 of the electrode 3 and the potential Vout of the electrodes 4 and 10 are the reference voltage 0V. Since the electrode 4 and the electrode 10 are connected to the ground via the resistor 12, and the electrode 3 is connected to the ground via the resistor 13, the piezoelectric members 1, 2, 8, and 9 are distorted. Because there is no.

  When the power supply voltage Vcc from the DC power supply is applied to the electrode 3 to the oscillation element 600, the piezoelectric member 1 and the piezoelectric member 8 are distorted. When the power supply voltage Vcc is equal to or higher than the saturation voltage of the piezoelectric member 1 and the piezoelectric member 8, a large distortion occurs in the piezoelectric member 1 and the piezoelectric member 8, and the piezoelectric member 2 and the piezoelectric member 9 as shown in FIG. As a result, a voltage is generated in the electrode 4 and the electrode 10 according to the magnitude of the distortion of the piezoelectric member 2 and the piezoelectric member 9.

  Here, since the piezoelectric member 2 and the piezoelectric member 9 are configured to generate a voltage having the same polarity as the power supply voltage Vcc, the applied voltages to the piezoelectric member 1 and the piezoelectric member 8 are increased as their distortion increases. Get smaller. When the applied voltage to the piezoelectric member 1 and the piezoelectric member 8 approaches zero, the distortion amount of the piezoelectric member 1 and the piezoelectric member 8 suddenly becomes zero, and accordingly, the distortion amount of the piezoelectric member 2 and the piezoelectric member 9. Becomes 0, and the voltage output to the electrode 4 and the electrode 10 also becomes substantially 0 and returns to the voltage at the moment when the power supply voltage Vcc is applied.

  Therefore, while the power supply voltage Vcc is applied to the oscillation element 600, an oscillation phenomenon that repeats generation and return of the voltage at the electrode 4 and the electrode 10 occurs. The output signal Vout from the electrode 10 has a waveform that vibrates at a high frequency.

  As described above, according to the oscillation element 600 of FIG. 6, a high frequency can be oscillated only by applying the power supply voltage Vcc.

  Further, as shown in FIG. 6, since the piezoelectric members 1 and 2 and the piezoelectric members 8 and 9 are arranged symmetrically around the joint between the piezoelectric members 1 and 8, the piezoelectric members 1 and 2 and the piezoelectric members Symmetric vibrations can be generated in the members 8 and 9, and as a result, vibrations generated in the vicinity of the electrode 3 can be suppressed. Thus, for example, the piezoelectric members 1, 2, 8, and 9 are supported at positions near the electrode 3 by using a support member (not shown) without disturbing the vibration of the piezoelectric members 1, 2 and the piezoelectric members 8, 9. can do.

  In the present embodiment, the resistor 12 may be composed of a variable resistor whose resistance value can be changed, whereby the oscillation frequency of this oscillation phenomenon can be easily changed. By using, for example, a FET or a combination of an analog switch and a resistor as such a variable resistor, the resistance value can be changed actively, and the oscillation frequency can be switched by an external signal. Become.

  The support member may be a power supply terminal (not shown). Thereby, the configuration of the oscillation element 600 can be further simplified.

  In the present embodiment, the antiferroelectric piezoelectric members 1 and 8 are arranged inside the ferroelectric piezoelectric members 2 and 9, but instead of this, the antiferroelectric piezoelectric members are arranged. The ferroelectric piezoelectric members 2 and 9 may be arranged on the inner side of 1 and 8. Thereby, the ferroelectric piezoelectric members 2 and 9 can be distorted from both sides, that is, the piezoelectric members 1 and 8 side, and a large strain can be generated.

  FIG. 8A is a circuit diagram showing a configuration of a first modification of the oscillation element 600 of FIG.

  6 has the same configuration as that of the voltage conversion element 100 of FIG. 1, the same components and elements as those of the voltage conversion element 100 are denoted by the same reference numerals. Those descriptions are omitted.

  In FIG. 8A, the oscillation element 800 includes a resistor 12 disposed between the electrode 3 and the ground defining the reference voltage 0 V, and a resistor 13 disposed between the electrode 3 and the electrode 5. The electrode 4 is connected to a power supply voltage Vcc from a DC power supply (not shown).

  In FIG. 8A, the output voltage from the piezoelectric member 2 is output as an output signal Vout through the electrode 5 and is positively fed back to the electrode 3 through the resistor 13. Control is performed so that the reciprocal α of the voltage dividing ratio of the resistor 12 and the resistor 13 is 1.5, for example, so that the value obtained by dividing the voltage output to the electrode 5 is substantially the same as the value of the power supply voltage Vcc. Has been.

  FIG. 9 is a diagram showing voltage waveforms of the respective electrodes in the oscillation element 800 of FIG.

  As shown in FIG. 9, when the DC power supply voltage Vcc is 0 V, most of the distortions of the piezoelectric member 1 and the piezoelectric member 2 are released, and the distortion amount is substantially zero.

  When the power supply voltage Vcc applied to the electrode 4 becomes equal to or higher than the saturation voltage of the piezoelectric member 1, the piezoelectric member 1 is greatly distorted. As a result, the piezoelectric member 2 is also greatly distorted and a large positive voltage is applied to the electrode 5. appear.

  Here, since the reciprocal α of the voltage dividing ratio by the resistor 12 and the resistor 13 is controlled so that the value obtained by dividing the voltage generated at the electrode 5 is substantially the same as the value of the power supply voltage Vcc, the piezoelectric member 2 has a large value. When the distortion occurs, the voltage applied to the piezoelectric member 1 becomes 0 V, and the distortion of the piezoelectric member 1 is released. With this, the distortion of the piezoelectric member 2 is also released, and the distortion becomes substantially zero. The state returns to the moment when the voltage Vcc is applied.

  Accordingly, in the oscillation element 800, while the power supply voltage Vcc is applied, an oscillation phenomenon that repeats generation and return of the voltage at the electrode 5 occurs, and thus the output signal Vout from the electrode 5 oscillates at a high frequency. It has a waveform to do. Note that the oscillation signal is not limited to the output signal Vout of the electrode 5, and the output signal V3 of the electrode 3 may be used.

  In the present modification, the resistance values of the resistor 12 and the resistor 13 may be changed at the same ratio so as not to change the voltage dividing ratio, whereby the frequency of the oscillation phenomenon can be easily changed. The frequency of the oscillation phenomenon may be changed by inserting a capacitor (not shown) between the electrode 3 and the electrode 4.

  FIG. 8B is a circuit diagram showing a configuration of a second modification of the oscillation element 600 of FIG.

  An oscillation element as a second modification of the oscillation element 600 in FIG. 6 has the same configuration as that of the oscillation element 800 in FIG. A description thereof will be omitted.

  In FIG. 8B, the oscillation element 900 includes a voltage conversion element 900b that is provided between the electrode 5 and the output terminal and is similar to the amplification element 300 in FIG. This voltage conversion element 900b includes an antiferroelectric piezoelectric member 8 having hysteresis characteristics indicated by a solid line in FIG. 2 to which an output voltage of the ferroelectric piezoelectric member 2 is applied, a ferroelectric piezoelectric member 9, and And is connected in series to a first voltage conversion element 900a composed of piezoelectric members 1 and 2. The output voltage Vout from the piezoelectric member 9 is positively fed back to the antiferroelectric piezoelectric member 1.

  According to the oscillation element 900 of FIG. 8B, since the second voltage conversion element 900b is provided, for example, an oscillator having a low oscillation frequency can be easily configured. Note that not only the second voltage conversion element 900b but also one or more other voltage conversion elements may be connected in series to the first voltage conversion element 900a.

  FIG. 10 is a circuit diagram schematically showing a configuration as an apparatus using the voltage conversion element according to the fourth embodiment of the present invention.

  In FIG. 10, a recording apparatus 1000 using the voltage conversion element according to the present embodiment includes a selector 21 to which a refresh signal (RF signal) and a Din signal are input, an AND circuit 16 connected to the selector 21, and an AND circuit. The first voltage conversion element 1000a connected to the circuit 16, the second voltage conversion element 1000b, and the third voltage conversion element 1000c connected to the first voltage conversion element and the second voltage conversion element 1000b. And an OR circuit 22 to which an RF signal and an En signal are input, and an AND circuit 17 connected to the selector 21 via an inverting circuit 18. The second voltage conversion element 1000 b inputs the V4 signal to the selector 21 via the electrode 4. The third voltage conversion element 1000c outputs an output signal Vout through the electrode 14a.

  In the second voltage conversion element 1000b, the electrode 3 and the electrode 5 are connected to the ground that defines the ground voltage, and the signal input to the electrode 4 connected to the bonding member between the piezoelectric members 1 and 2 is stored. It is configured as a storage element. The output voltage of the piezoelectric member 2 is configured to be the same as the polarity of the power supply voltage.

  A transistor 23 is disposed between the electrodes 4 of the first voltage conversion element 1000a and the second voltage conversion element 1000b, and between the electrode 4 of the second voltage conversion element 1000b and the third voltage conversion element 1000c. The transistor 24 is disposed, and the transistor 20 that clamps the voltage of the electrode 4 with the ground voltage is disposed between the ground and the electrode 4 of the second voltage conversion element 1000b.

  The piezoelectric members 1, 8, and 14 are made of an antiferroelectric material having hysteresis characteristics shown by the solid line in FIG. 2, and the piezoelectric members 2, 9, and 15 are made of a ferroelectric material.

  FIG. 11 is a diagram illustrating voltage waveforms of the respective electrodes in the recording apparatus 1000 of FIG.

  In FIG. 11, first, when the En signal is high (Hi) and the RF signal is low (Lo), the selector 21 selects and outputs the Din signal. When the Din signal is Hi, the output voltage of the AND circuit 16 becomes Hi, and in the first voltage conversion element 1000a, the ferroelectric piezoelectric member 9 is larger than the power supply voltage Vcc via the diode 23 and has a polarity. A positive voltage is output to the electrode 4 and is output to the ferroelectric piezoelectric member 15 of the third voltage conversion element 1000 c via the diode 24. Since electric charge also flows into the piezoelectric member 15, the output voltage of the piezoelectric member 15 becomes substantially equal to the power supply voltage Vcc. On the other hand, when the Din signal is Lo, the output voltage of the AND circuit 17 becomes Hi, and in the third voltage conversion element 1000c, the ferroelectric piezoelectric member 15 is a voltage having a magnitude larger than the power supply voltage Vcc and a negative polarity. Is output toward the electrode 4. As a result, the voltage of the electrode 4 is clamped at the ground voltage by the diode 20 and becomes approximately 0V.

  At times T1 and T2 in FIG. 11, the Din signal storage operation is performed by the second voltage conversion element 1000b.

  Specifically, since the Din signal is Hi at time T1, a voltage higher than the power supply voltage Vcc is applied to the antiferroelectric piezoelectric member 1 in the second voltage conversion element 1000b. Then, the piezoelectric member 1 is greatly distorted, and accordingly, the piezoelectric member 2 is also greatly distorted. Since the output voltage of the piezoelectric member 2 is configured to be the same as the polarity of the power supply voltage Vcc, a voltage larger than the power supply voltage Vcc is input to the electrode 4 from the second voltage conversion element 1000b.

  At this time, when the third voltage conversion element 1000c is turned off (OFF), the output voltage from the third voltage conversion element 1000c becomes 0V and the diode 23 is turned off. Therefore, a voltage higher than the power supply voltage Vcc applied from the second voltage conversion element 1000b remains on the electrode 4. Further, the remaining voltage is not discharged even when the power supply voltage Vcc becomes the ground voltage. Thus, the second voltage conversion element 1000b can constitute a nonvolatile storage element that stores a signal corresponding to the remaining voltage. For example, when such a storage element is used as a sensor, it is possible to easily detect a single phenomenon, for example, the occurrence of a small distortion, without always monitoring all output signals.

  Next, at time T2, since the Din signal is Lo, the voltage of the electrode 4 finally becomes 0V. Thereby, the distortion of the piezoelectric member 1 is released and the distortion of the piezoelectric member 2 is also released, so that the output voltage of the second voltage conversion element 1000b becomes 0V.

  In the time from time T3 to time T4, the selector 21 switches to either the Din signal or the V4 signal in accordance with the input RF signal, and the switched signal is output from the AND circuit 16 and the inverting circuit 18. Output to both. The selector 21 is configured to output a Din signal when the RF signal is Lo, and to output a V4 signal when the RF signal is Hi. The second voltage conversion element 1000b receives the RF signal or the En signal. A storage operation for storing the output signal of the selector 21 is performed when the output is Hi. That is, the second voltage conversion element 1000b performs the operation of re-storing the V4 signal at the timing when the RF signal becomes Hi because the En signal is Lo at times T3 and T4.

  According to the recording apparatus 1000 in FIG. 10, the voltage corresponding to the distortion generated in the piezoelectric member 2 is stored, and the stored content is stored again before the stored voltage is completely discharged after a long time has elapsed. can do.

  FIG. 12A to FIG. 12F are circuit diagrams schematically showing a configuration of a logic element as a device using the voltage conversion element according to the fifth embodiment of the present invention.

  The logic element 1200a shown in FIG. 12A is configured as an inverting element.

  Since the logic element 1200a has the same configuration as that of the amplifying element 500 in FIG. 5, the same components and elements as those of the amplifying element 500 are denoted by the same reference numerals, and description thereof is omitted. A power supply voltage Vcc is applied to the electrode 6 and a ground is connected to the electrode 4. The electrode 5 is configured to output a negative polarity voltage.

  Further, the logic element 1200a includes diodes 19 and 20 (clipping circuit) that perform clipping so that the output voltage Vout from the output voltage of the electrode 5 is limited between the power supply voltage and the ground voltage between the electrode 5 and the output terminal Vout. ).

  Hereinafter, the inversion operation of the logic element 1200a will be described.

  When a saturation voltage is applied to the electrode 3 of the piezoelectric member 1, the piezoelectric member 1 is greatly distorted and the piezoelectric member 2 is greatly distorted. Here, since a negative polarity voltage is output to the electrode 5, a voltage equal to the power supply voltage Vcc is output to the electrode 5 when the distortion of the piezoelectric member 2 is zero, and the electrode 5 when the distortion of the piezoelectric member 2 is large. Output of approximately 0V.

  Therefore, when a voltage of 0 V is applied to the electrode 3, the distortion of the piezoelectric member 1 is released, the distortion of the piezoelectric member 2 is also released, and the potential difference between the electrode 6 and the electrode 5 becomes 0 V. A voltage equal to the power supply voltage Vcc is output.

  Although the inverting element is configured in the present embodiment, the buffer element can be configured by reversing the polarity of the output voltage Vout of the piezoelectric member 2 and connecting the electrode 6 to the ground that defines the ground voltage.

  The logic element 1200b shown in FIG. 12B is configured as an XOR circuit.

  The logic element 1200b includes an antiferroelectric piezoelectric member 1 having hysteresis characteristics shown by a solid line in FIG. 2, a ferroelectric piezoelectric member 2, electrodes 3 and 4 to which an input signal is input, and an output signal. An electrode 5 for outputting Vout and an electrode 6 connected to an earth for defining a ground voltage are provided.

  Hereinafter, the operation of the logic element 1200b will be described.

  When the logics indicated by the two input signals inputted to the electrode 3 and the electrode 4 are the same, the piezoelectric member 1 is not distorted, so that the piezoelectric member 2 is not distorted and the output signal Vout of the electrode 5 becomes 0V.

  On the other hand, when the voltage at the input terminal of one of the electrode 3 and the electrode 4 becomes equal to the power supply voltage, a saturation voltage is applied to the piezoelectric member 1 and a large distortion occurs. Here, since the antiferroelectric piezoelectric member 1 has a characteristic of extending in a direction in which a voltage is applied, as a result, the piezoelectric member 2 extends in the same direction as the piezoelectric member 1. Here, when the piezoelectric member 2 is extended, the output voltage of the electrode 5 is configured to be a positive voltage, whereby a positive voltage is output to the electrode 5. Normally, the material, dimensions, etc. of the piezoelectric member 2 are designed so that the output voltage of the electrode 5 is substantially equal to the power supply voltage.

  The logic element 1200c shown in FIG. 12C is configured as a three-input OR circuit.

  The logic element 1200c includes antiferroelectric piezoelectric members 1, 25, 26 having hysteresis characteristics shown by a solid line in FIG. 2, the ferroelectric piezoelectric member 2, the electrode 3 of the piezoelectric member 1, and the piezoelectric member 25. The electrode 27 and the electrode 28 of the piezoelectric member 26 are provided.

  When a power supply voltage is applied to at least one of the electrode 3, the electrode 27, and the electrode 28, the saturation voltage of the piezoelectric member connected to the electrode is exceeded and a large distortion occurs. A large distortion also occurs. Here, when a large distortion due to the saturation voltage occurs in at least one of the three antiferroelectric piezoelectric members 1, 25 and 26, the piezoelectric member 2 generates a voltage larger than the power supply voltage. By configuring so, the output voltage Vout of the electrode 5 becomes larger than the power supply voltage.

  The logic element 1200d shown in FIG. 12D is configured as a 3-input AND circuit.

  The logic element 1200d has a configuration similar to that of the logic element 1200c of FIG. 12C, and the same reference numerals are given to the same configurations and elements, and description thereof is omitted.

  The logic element 1200 d is configured such that the power supply voltage Vcc is applied to the electrode 4. Here, when the voltage of at least one of the electrode 3, the electrode 27, and the electrode 28 is set to 0 V, three antiferroelectric piezoelectric members 1, 25, 26 having hysteresis characteristics shown by the solid line in FIG. A saturation voltage is applied to at least one of the piezoelectric members, and large distortion occurs. Here, when a large distortion due to the saturation voltage occurs in at least one antiferroelectric piezoelectric member, the piezoelectric member 2 generates a voltage having a polarity opposite to that of the power supply voltage Vcc and a magnitude greater than the power supply voltage Vcc. With this configuration, the output voltage of the electrode 5 becomes 0 V or less.

  The logic element 1200e shown in FIG. 12E is configured as a NOR circuit in which one input is negative logic.

  The logic element 1200e is provided between the piezoelectric members 1 and 25, the ferroelectric member 2 having the hysteresis characteristics shown by the solid line in FIG. An insulating member 7 that electrically insulates between the electrode 4 and the electrode 6, an electrode 3 of the piezoelectric member 1, an electrode 4 connected to a joint provided between the piezoelectric member 1 and the insulating member 7, An electrode 27 of the piezoelectric member 25, an electrode 5 of the piezoelectric member 2, and an electrode 6 connected to a joint provided between the piezoelectric members 1, 25 and the piezoelectric member 2 are provided.

  The electrode 3 of the piezoelectric member 1 is connected to the positive logic input terminal A, and the electrode 27 of the piezoelectric member 25 is connected to the negative logic input terminal B. The electrode 4 is connected to an earth that defines the ground voltage, and the power supply voltage Vcc is applied to the electrode 6.

  When a voltage equal to or higher than a predetermined saturation voltage is applied to the electrode 3 via the positive logic input terminal A, large distortion occurs in the piezoelectric member 1. When a ground voltage is applied to the electrode 27, large distortion occurs in the piezoelectric member 25. When the piezoelectric member 2 is distorted according to the distortion of at least one of the piezoelectric member 1 and the piezoelectric member 25, the output voltage Vout becomes 0V or less. On the other hand, the piezoelectric member 2 outputs the power supply voltage Vcc applied through the electrode 6 when both the piezoelectric member 1 and the piezoelectric member 25 are not distorted.

  A logic element 1200f shown in FIG. 12F is configured as an inverting element of a Schmitt trigger input.

  The logic element 1200f includes an inverting element composed of the piezoelectric member 1 having the hysteresis characteristic shown by the solid line in FIG. 2 and the ferroelectric piezoelectric member 2, and the piezoelectric member 8 having the hysteresis characteristic shown in the solid line in FIG. And a buffer element made of a piezoelectric member 9 having a conductive property. The buffer element is configured to increase the amplification factor so that the output voltage of the piezoelectric member 9 becomes larger than the power supply voltage Vcc when the piezoelectric member 8 is greatly distorted. Diodes 19 and 20 are provided so that the output voltage of the member 9 is clamped between the power supply voltage Vcc and the ground voltage.

  According to the logic element 1200f, since the input voltage can be amplified by the buffer element, even when the input voltage from the electrode 3 to the piezoelectric member 1 is lower than the saturation voltage of the piezoelectric member 1, it is amplified to the saturation voltage. can do. That is, by increasing the amplification factor of the buffer element, it is possible to reduce the input voltage necessary for generating a large distortion in the piezoelectric member 1.

  In addition, since the output voltage of the piezoelectric member 9 is clamped via the diode 19, it is possible to provide an inverting element that can change the amount of hysteresis by changing the magnitude of the amplification factor of the buffer element. For example, the voltage required to release the distortion of the piezoelectric member 1 can be increased according to the gain of the buffer element. Further, although the clipping circuit by the diodes 19 and 20 is provided only for the output of 1200a in FIG. 12 (a), the output of the logic elements 1200b to 1200f using the voltage conversion elements of FIG. 12 (b) to FIG. 12 (f) is provided. Also, such a clipping circuit may be provided.

  FIG. 13 is a circuit diagram schematically showing a configuration of a refresh circuit for refreshing (recharging) the output charge of the logic element as shown in FIGS. 12 (a) to 12 (f).

  In FIG. 13, a refresh circuit 1300 is for refreshing (recharging) the output charge of the logic element as described above, and includes a piezoelectric member 1 having ferroelectric characteristics shown by a solid line in FIG. A buffer element composed of the piezoelectric member 2, an AND circuit 16 to which a refresh signal (RF signal) and a normal rotation input of the buffer element are input, and a piezoelectric element having hysteresis characteristics connected to the AND circuit 16 and indicated by a solid line in FIG. A first voltage conversion element comprising a member 8, a ferroelectric piezoelectric member 9, a diode 23 connected to the output terminal of the buffer element, an inverting element 18 for inverting the input of the buffer element, an RF signal and a buffer element AND circuit 17 to which the inverting input is input, and piezoelectric member 14 having hysteresis characteristics connected to AND circuit 17 and indicated by the solid line in FIG. A second voltage conversion element made of a ferroelectric piezoelectric member 15, a diode 24 connected to the output terminal of the second voltage conversion element, and a diode for clamping the output voltage of the buffer element to the power supply voltage Vcc and the ground voltage 19 and 20.

  Hereinafter, the operation of the refresh circuit 1300 will be described. The piezoelectric members 1, 8 and 14 are made of the above-described high performance piezoelectric material, and the piezoelectric members 2, 9 and 15 are made of a ferroelectric material.

  In FIG. 13, first, when the RF signal becomes Hi, the output signals of the AND circuits 16 and 17 become active in accordance with the output signals of the buffer elements.

  Specifically, when the output signal of the buffer element, that is, the voltage of the electrode 5 is Hi, the AND circuit 16 becomes active. In response to this, the buffer element operates so as to further enhance the Hi level of the voltage of the electrode 5 by outputting a positive voltage greater than the power supply voltage Vcc through the diode 23.

  On the other hand, when the voltage of the electrode 5 is at the Lo level, the AND circuit 17 is activated by the action of the inverting element 18. In response to this, the voltage conversion element outputs a voltage higher than the negative power supply voltage Vcc, and operates to further enhance the Lo level of the electrode 5 via the diode 24.

  According to the refresh circuit 1300, even if the output charge of the piezoelectric member 2 is discharged by the floating resistance or the output voltage of the piezoelectric member 2 drifts due to the pyroelectric effect, the output voltage of the piezoelectric member 2 is periodically reset. Thus, malfunction of the buffer element can be prevented.

  Further, the refresh circuit 1300 has a charge of the ferroelectric piezoelectric member 2 when the amount of charge to be output by the buffer element is insufficient, such as when the number of elements connected to the output of the buffer element is large. It is also possible to function as a charge replenishment circuit for compensating for the above.

  Note that the refresh circuit 1300 is not limited to the buffer element, but may be applied to an element including other voltage conversion elements.

  The voltage conversion element and the apparatus using the voltage conversion element according to each embodiment described above can constitute various circuit elements having a predetermined function according to the polarization direction of the piezoelectric member and the arrangement of the wiring. Since the piezoelectric member 2 is a charge generating means for generating electric charges and is also a capacitor for converting electric charges into voltage, the total amount of distortion generated in the plurality of piezoelectric members 2 can be obtained by simply connecting the piezoelectric members in parallel. Can be converted to As a result, it is possible to detect the total amount of distortion generated in the plurality of piezoelectric members 1 as the total output charge of the piezoelectric member 2 and to easily convert this charge into a voltage with a simple configuration. .

  Furthermore, as described above, according to the apparatus using the voltage conversion element according to each embodiment, an oscillation element, a storage element, an amplification element that amplifies the power supply voltage Vcc or higher can be configured, and the like. By using these, a complicated integrated circuit can be configured. In addition, the device using the voltage conversion element has not only a small number of elements and a simple circuit configuration, but also functions basically by generating and extinguishing charges, so that it is possible to reduce wasteful power loss. . As a result, even an integrated circuit configured from a device using these voltage conversion elements can not only simplify the configuration but also reduce power consumption.

  It is also possible to vibrate a device using these voltage conversion elements at high speed. In this case, it is preferable to take measures such as providing a buffer member between devices using each voltage conversion element or floating and supporting the piezoelectric member by a support member such as an electrode member. In addition, it is preferable to arrange the piezoelectric member symmetrically about the support member and arrange the support member in the neutral portion of the vibration. Thereby, transmission of unnecessary vibration can be suppressed.

  In addition, an apparatus using each voltage conversion element can be used as a microactuator by utilizing distortion generated in the piezoelectric member. For example, a multi-channel optical switch can be configured by minutely displacing a large number of optical elements. Further, by using the voltage conversion element as a strain sensor, it can be applied to a gyro function, a pressure sensor, a fingerprint sensor, and the like.

  An integrated circuit in which two or more devices using these voltage conversion elements are connected will be described.

  Since devices using these voltage conversion elements cannot amplify power, an integrated circuit in which devices using a plurality of voltage conversion elements are connected in series does not have enough charge to transmit signals. It may be difficult to perform accurately. In order to avoid this, it is necessary to gradually connect logic elements having a small charge capacity in series, or to arrange a charge amplifier circuit for charge supplementation between the logic elements.

  In addition, the devices using the various voltage conversion elements described above can be applied in combination with transistors, FETs, and the like, which are current control means capable of controlling the output current. It is preferable to design integrated circuits. Of these, FETs have a very high input impedance, and are particularly preferable because they have good compatibility with devices using piezoelectric Debye voltage conversion elements.

  FIG. 14 is a diagram schematically showing a configuration of an integrated circuit as a device using the voltage conversion element according to the sixth embodiment of the present invention.

  In FIG. 14, an integrated circuit 1400 using the voltage conversion element according to the present embodiment includes an LSI (large scale integration) 29 formed on a predetermined substrate, and a polarization voltage provided on the outer peripheral edge of the LSI 29. The input pin 30, the polarization control unit 31 connected to the polarization voltage input pin 30, the plurality of polarization voltage dedicated wirings 32 provided on the LSI 29, the plurality of wirings 34 connecting the circuit elements, and the wiring 34 And a wiring control unit 33 connected to the.

  In the integrated circuit 1400, an external signal is output from the polarization control unit 31 to each circuit element via the polarization voltage supply dedicated wiring 32. The plurality of circuit elements connected via the plurality of wirings 34 are externally connected to each other based on information on the presence / absence of polarization of the piezoelectric member and information on polarization composed of the direction of the polarization, and information on connection with other circuit elements. A function corresponding to the signal is realized. The wiring control unit 33 is configured to construct a complex program by combining a plurality of these functions. The circuit elements preferably include a storage element having a minimum necessary capacity for storing information of the final integrated circuit 1400 and circuit. Accordingly, it is possible to eliminate the need to previously provide a large-capacity storage device in the integrated circuit 1400.

  Hereinafter, a method for manufacturing the integrated circuit 1400 will be described.

  First, necessary semiconductor devices are formed on a substrate made of, for example, silicon or ceramic. Next, an antiferroelectric piezoelectric member having hysteresis characteristics shown by the solid line in FIG. 2 is formed. Subsequently, a ferroelectric piezoelectric member is formed, and finally wiring is performed. The polarization treatment of the piezoelectric member may be performed at the time of manufacture or may be programmed later.

  When polarization is performed at the time of manufacture, devices having different polarization directions are prepared in advance, and can be configured to be selectively connected to either one of these devices via the polarization voltage dedicated wiring 32 or the wiring 34, or in an initial state. The polarization state may be programmed so that

  FIG. 15 is a circuit diagram schematically showing a configuration of a speaker as a device using the voltage conversion element according to the seventh embodiment of the present invention.

  In FIG. 15, a speaker 1500 as a device using the voltage conversion element according to the present embodiment constitutes a piezoelectric buzzer, and its drive circuit constitutes an oscillation circuit similar to the amplification element 300 of FIG. .

  The speaker 1500 includes an antiferroelectric piezoelectric member 35 having a hysteresis characteristic shown by a solid line in FIG. 2, a ferroelectric piezoelectric member 36, and a sounding body and an electrode that generate sound by vibrating at a predetermined oscillation frequency. An elastic member 37 that also serves as power supply electrodes 38 and 39 is provided.

  The operation of the speaker 1500 will be described.

  First, when a DC voltage is applied between the electrode 38 and the electrode 39, the piezoelectric member 35 is greatly distorted and the elastic member 37 is distorted. Subsequently, the piezoelectric member 36 is distorted, and a voltage close to the power supply voltage Vcc is generated in the elastic member 37. As a result, the voltage applied to the piezoelectric member 35 becomes approximately 0 V, and the distortion of the piezoelectric member 35 is released. Next, when the distortion of the elastic member 37 is released, the piezoelectric member 36 is released from the distortion and its output voltage becomes 0V. Subsequently, the piezoelectric member 35 is distorted again, and the above-described operation is repeated. Therefore, the elastic body 37 as a sounding body emits a buzzer sound based on vibration generated by repeated generation and release of distortion while supplying the power supply voltage Vcc to the piezoelectric member 35.

  In the above embodiment, a power supply voltage may be applied to the piezoelectric member 35 that forms part of the sounding body, and the voltage from the piezoelectric member 36 may be fed back to the piezoelectric member 35. As a result, the sounding body can be vibrated at a predetermined oscillation frequency. Furthermore, the speaker 1500 may include a filter that filters the voltage from the piezoelectric member 36 to be fed back to the piezoelectric member 35 by connecting the elastic body 37 and the electrode 39 with a resistor (not shown).

  FIG. 16 is a circuit diagram schematically showing a configuration of a vibration type actuator as a device using the voltage conversion element according to the eighth embodiment of the present invention.

  In FIG. 16, a vibration type actuator 1600 as a device using the voltage conversion element according to the present embodiment includes an antiferroelectric piezoelectric member 40 having hysteresis characteristics shown by a solid line in FIG. The piezoelectric member 41, electrodes 42, 43, 44, an elastic body 45 having a protrusion 45 a at the top, and a rotating body 46 that pressurizes the protrusion 45 a of the elastic body 45 in pressure. The electrode 44 and the elastic body 45 are electrically connected, and the elastic body 45 is connected to an earth that defines a ground voltage.

  The drive circuit of the vibration type actuator 1600 is the same as that of the speaker 1500 of FIG. 15, and the operation thereof will be schematically described below.

  First, when a DC voltage is applied between the electrode 42 and the electrode 44, the piezoelectric member 40 and the piezoelectric member 41 repeat an oscillation phenomenon, whereby the elastic body 45 repeats flexural vibration, thereby causing the protrusion 45a of the elastic body 45 to repeat. Vibrates in the circumferential direction of the rotating body 46, and the rotating body 46 rotates in a predetermined direction.

  The rotational speed of the rotator 46 can be changed by turning on and off the application of voltage between the electrode 42 and the electrode 44 and changing the ON-OFF cycle and duty ratio. This is because the amplitude of the vibration of the protrusion 45a is almost constant regardless of the power supply voltage Vcc.

  Alternatively, the oscillation frequency of the protrusion 45a (the oscillation frequency of the elastic body 45) may be changed by connecting variable resistance means between the electrode 43 and the ground voltage and changing the resistance value. Thereby, the rotational speed of the rotating body 46 can be controlled more accurately.

  In this embodiment, the vibration type actuator is configured using the oscillation function of the device using the voltage conversion element. However, the laminated actuator is configured using the storage function of the device using the voltage conversion element. Also good. Multi-layer actuators can not only digitally control the amount of strain by switching only the necessary sections of a plurality of stacked piezoelectric members and apply a saturation voltage, but also can store the strain in each layer. Even if the supply is stopped, distortion can be stabilized for a long time.

  FIG. 17 is a circuit diagram schematically showing a configuration of a sensor as a device using the voltage conversion element according to the ninth embodiment of the present invention.

  In FIG. 17, a sensor 1700 as a device using the voltage conversion element according to the present embodiment is distorted by an antiferroelectric piezoelectric member 1 having hysteresis characteristics shown by a solid line in FIG. 2 and external force. A ferroelectric piezoelectric member 2, electrodes 3 and 5 connected to an earth for defining a ground voltage, and an electrode 4 to which a positive voltage according to the distortion of the piezoelectric member 2 is applied.

  In the sensor 1700, first, when a distortion occurs in the piezoelectric member 2 due to an external force, a positive voltage corresponding to the distortion of the piezoelectric member 2 is generated in the electrode 4. When the voltage generated at the electrode 4 exceeds the saturation voltage of the piezoelectric member 1, a large distortion occurs in the piezoelectric member 1, and accordingly, further distortion occurs in the piezoelectric member 2. Thereby, even if the external force is removed, the sensor 1700 is in a state in which the distortion of the piezoelectric member 2 is memorized, so that the positive output voltage Vout output to the electrode 4 exceeds the predetermined threshold value. It functions as a sensor that indicates whether or not

  Note that the surface pressure distribution of the strain generated in the plurality of piezoelectric members 2 may be stored by arranging a plurality of such sensors 1700 in a plane. Further, the stored magnitude of the distortion may be detected by using a plurality of sensors in which the magnitude of the external force stored as the distortion is changed.

  FIG. 18 is a circuit diagram schematically showing a configuration of a digital / analog conversion circuit as a device using the voltage conversion element according to the eighth embodiment of the present invention.

  In FIG. 18, a digital / analog (D / A) conversion circuit 1800 as a device using the voltage conversion element according to the present embodiment is composed of a 2-bit D / A conversion circuit, and the hysteresis shown by the solid line in FIG. In order to adjust the gain of the voltage output through the electrodes 5, 4, 5, 27, the anti-ferroelectric piezoelectric members 1, 25 having the characteristics, the ferroelectric piezoelectric member 2, the electrodes 3, 4, 5, 27 The capacitor 47 is provided. An electrode 4 is connected to a bonding member between the piezoelectric members 1 and 25 and the piezoelectric member 2, and the electrode 4 is connected to a ground that defines a ground voltage.

  A D1 signal is input to the piezoelectric member 1 through the electrode 3. The D0 signal is input to the piezoelectric member 25 through the electrode 27. The electrode area of the piezoelectric member 25 is, for example, half that of the piezoelectric member 1. The piezoelectric member 1 and the piezoelectric member 25 are configured to generate the same distortion amount with the same input value. Since the electrode area of the piezoelectric member 25 is half that of the piezoelectric member 1, even if the same amount of distortion occurs in the piezoelectric member 1 and the piezoelectric member 25, the charge amount input to the piezoelectric member 2 by the piezoelectric member 25 is the piezoelectric member 1. Is half the amount of charge input to the piezoelectric member 2.

  In the D / A conversion circuit 1800, the electric charge generated in the piezoelectric member 2 in response to the D0 signal and the D1 signal is applied to the electrode 5 as a voltage. Since the capacitance of the parallel circuit composed of the piezoelectric member 2 and the capacitor 47 hardly changes, the output voltage Vout corresponding to the generated charge amount can be taken out.

  In this embodiment, a 2-bit D / A conversion circuit is configured, but a 1-bit or more D / A conversion circuit can be configured.

  FIG. 19 is a circuit diagram schematically showing a configuration of an analog / digital conversion circuit as a device using the voltage conversion element according to the ninth embodiment of the present invention.

  In FIG. 19, an analog / digital (A / D) conversion circuit 1900 as a device using the voltage conversion element according to the present embodiment includes piezoelectric members 1 and 2 in the 2-bit D / A conversion circuit 1800 of FIG. , 25, a second voltage conversion element 1900b consisting of ferroelectric piezoelectric members 48, 49, and between the first voltage conversion element 1900a and the second voltage conversion element 1900b. The capacitor 47 connected to the electrode 5 provided in the D / A conversion control unit 50 that controls the first voltage conversion element 1900a.

  When an analog voltage is input to the piezoelectric member 48 via the electrode Vin, a charge proportional to the analog voltage is output to the electrode 5. Here, if the D / A conversion control unit 50 controls the first voltage conversion element 1900a to distort the piezoelectric member 2, the difference between the charge proportional to the analog voltage and the output charge of the first voltage conversion element 1900a is caused. A corresponding voltage is generated in the capacitor 47. At this time, the D / A conversion control unit 50 detects the sign of the voltage generated in the capacitor 47 and changes the digital signal to be input to the first voltage conversion element 1900a so that this voltage approaches 0V. Thus, the value of the digital signal input to the first voltage conversion element 1900a is equal to the value obtained by converting the analog voltage into a digital signal.

  In the present embodiment, the distortion generated in the piezoelectric member 48 according to the analog voltage is converted into a voltage by the piezoelectric member 49, but instead, the piezoelectric member 49 is caused to generate distortion according to an external force. Distortion may be converted to voltage. Thereby, the magnitude of the external force can be converted into a digital signal.

  In this embodiment, a 2-bit D / A conversion circuit is configured, but a 1-bit or more D / A conversion circuit can be configured.

  FIG. 20 is a circuit diagram schematically showing a configuration of a power storage element as a device using the voltage conversion element according to the tenth embodiment of the present invention.

  20, a storage element 2000 as an apparatus using the voltage conversion element according to the present embodiment includes a piezoelectric member 1 having hysteresis characteristics shown by a solid line in FIG. 2 and a piezoelectric member 2 made of a ferroelectric material. A storage element, electrodes 3 and 5 connected to an earth for defining a ground voltage, a diode 19 connected to a charging terminal, and an electrode 4 connecting the diode 19 and the storage element. The electrode 4 is connected to a voltage output.

  When a voltage of a predetermined level or more is applied from the charging terminal to the electrode 4 via the diode 19, a large distortion is generated in the piezoelectric member 1, and the piezoelectric member 2 is distorted along with this, via the electrode 4. A voltage is output from the voltage output. Since the magnitude of the distortion of the piezoelectric member 1 is determined by its hysteresis characteristics, the magnitude of the voltage output from the piezoelectric member 2 is almost stable.

  As an output voltage characteristic of the electric storage element 2000, when the electric charge charged by the output of current is reduced, the voltage of the electrode 4 becomes a predetermined level or less due to the hysteresis characteristic of the piezoelectric member 1, and the piezoelectric member 1 is suddenly reduced. As a result, the output voltage becomes 0 V. In some cases, the output voltage may be a negative voltage. Therefore, it is preferable to provide a protection circuit using a diode at the voltage output terminal. .

  According to the power storage device 2000 of FIG. 20, a large output voltage can be extracted with a small charge voltage. In addition, since it is made of a solid, it is possible to eliminate the risk of liquid leakage.

  In order to increase the charge capacity of power storage element 2000, a plurality of memory elements are connected in parallel, or are thinly formed using piezoelectric members 1 and 2 having a large electrode area, or these are wound in a cylindrical shape. Or may be configured.

  A capacitor may be connected in parallel to the voltage output terminal. Thereby, a voltage can be changed easily. Further, the memory element composed of the piezoelectric members 1 and 2 may be housed in a housing (not shown). By preliminarily applying a pressure against the strain from the outside, it is possible to efficiently transmit the strain generated in the piezoelectric member 1 to the piezoelectric member 2 and improve the storage efficiency.

  In this embodiment, power storage device 200 is configured using a voltage conversion element. However, an oscillation element that oscillates with a DC voltage may be configured, or an AC power source may be configured by combining these.

  In the above embodiment, for ease of explanation, a piezoelectric member made of an antiferroelectric material having hysteresis characteristics shown by a solid line in FIG. 2 and a piezoelectric member made of a ferroelectric material are adjacent to each other. As described above, when one member is an electro-mechanical energy conversion element and the other member is a mechanical-electric energy conversion element, the above piezoelectric member is not necessarily used. There is no need to be configured.

  The point-defect electrostrictive material described in Non-Patent Document 1 has the same hysteresis characteristics as the conventional antiferroelectric piezoelectric material (strain characteristics with respect to the electric field strength). Compared with an antiferroelectric piezoelectric material, it is possible to generate an equivalent strain with an electric field strength of several tens to one hundredths. Therefore, a piezoelectric member that generates a large strain at a low voltage can be used, and application to various uses has been studied.

Since these voltage conversion elements have a large distortion generated in the piezoelectric member constituting the voltage conversion element, it is necessary to take measures against peeling and fracture of the electrodes due to the distortion. The present invention relates to an electro - to generate a large distortion at some mechanical energy conversion element antiferroelectric piezoelectric members, the machine adjacent thereto - to convert the voltage ferroelectric piezoelectric member is an electric energy conversion device There is a possibility that a large stress is applied to the adjacent interface. An example of a method for reducing the stress at the interface is given below.

  As a first method, there is a method in which the electrode at the interface is divided into a plurality of regions and the plurality of regions are arranged at an appropriate distance from each other. By arranging the plurality of regions in parallel with the interface, the component in the direction parallel to the interface of the electric lines of force increases. When distortion in the direction of increasing thickness occurs due to the electric field in the thickness direction, the contraction by the Poisson's ratio works in the direction perpendicular to the thickness direction, but here the electric field lines are parallel to the interface perpendicular to the thickness direction. By providing a directional component, a strain extending in a direction perpendicular to the thickness direction is added, and the strain in a direction parallel to the interface can be reduced. Since this method changes the distortion transmission rate, it can also be used to adjust the gain of the voltage conversion element.

  As a second method, there is a method of filling fine irregularities generated on the contact surface between the piezoelectric member and the electrode with a high dielectric constant gel or a conductive gel. In this case, it is necessary to apply pressure to the voltage conversion element in order to efficiently transmit the strain.

  As a third method, there is a method of using a soft material for the electrode itself.

  By applying such a device, it is possible to put it into practical use without damaging the voltage conversion element.

  The voltage conversion element according to the embodiment of the present invention can be applied to a device including an element utilizing the electro-mechanical energy conversion effect and the mechanical-electric energy conversion effect.

It is a figure which shows schematically the structure of the voltage conversion element which concerns on the 1st Embodiment of this invention. It is a figure which shows typically the distortion characteristic of the piezoelectric member which has a reversible electrostriction, and the ferroelectric piezoelectric member using the property of the symmetry of the nano order of a point defect. It is a circuit diagram which shows the structure of the amplification element as a voltage conversion element which concerns on the 2nd Embodiment of this invention. It is a figure which shows the signal waveform of each part of the amplification element of FIG. FIG. 4 is a circuit diagram schematically showing a configuration of a modified example of the amplifying element of FIG. 3. It is a circuit diagram which shows roughly the structure of the oscillation element as an apparatus using the voltage conversion element which concerns on the 3rd Embodiment of this invention. It is a figure which shows the voltage waveform of each electrode in the oscillation element of FIG. (A) is a circuit diagram showing a configuration of a first modification of the oscillation element of FIG. 6, and (b) is a circuit diagram showing a configuration of a second modification of the oscillation element of FIG. 6. It is a figure which shows the voltage waveform of each electrode in the oscillation element of Fig.8 (a). It is a circuit diagram which shows roughly the structure as an apparatus using the voltage conversion element which concerns on the 4th Embodiment of this invention. It is a figure which shows the voltage waveform of each electrode in the apparatus using the voltage conversion element of FIG. (A)-(f) is a circuit diagram which shows roughly the structure of the logic element as an apparatus using the voltage conversion element which concerns on the 5th Embodiment of this invention. FIG. 13 is a circuit diagram schematically showing a configuration of a refresh circuit for refreshing output charges of a logic element as shown in FIGS. 12 (a) to 12 (f). It is a figure which shows schematically the structure of the integrated circuit as an apparatus using the voltage conversion element which concerns on the 6th Embodiment of this invention. It is a circuit diagram which shows roughly the structure of the speaker as an apparatus using the voltage conversion element which concerns on the 7th Embodiment of this invention. It is a circuit diagram which shows roughly the structure of the vibration type actuator as an apparatus using the voltage conversion element which concerns on the 8th Embodiment of this invention. It is a circuit diagram which shows roughly the structure of the sensor as an apparatus using the voltage conversion element which concerns on the 9th Embodiment of this invention. It is a circuit diagram which shows roughly the structure of the digital / analog converting element as an apparatus using the voltage converting element based on the 8th Embodiment of this invention. It is a circuit diagram which shows roughly the structure of the analog / digital conversion element as an apparatus using the voltage conversion element which concerns on the 9th Embodiment of this invention. It is a circuit diagram which shows roughly the structure of the electrical storage element as an apparatus using the voltage conversion element which concerns on the 10th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antiferroelectric piezoelectric member which is an electro-mechanical energy conversion element 2 Ferroelectric piezoelectric member 3, 4, 5 which is a mechanical-electrical energy conversion element Electrode 100 Voltage conversion element

Claims (24)

A voltage conversion element having first and second energy conversion elements having different ratios of change in distortion amount to change in applied voltage,
The first energy conversion element is connected to a first terminal;
The second energy conversion element is connected to a second terminal different from the first terminal;
The first energy conversion element and the second energy conversion element are disposed adjacent to each other;
The ratio of the change in the amount of distortion to the change in the applied voltage in the second energy conversion element is smaller than the ratio of the change in the amount of distortion to the change in the applied voltage in the first energy conversion element.
The second energy conversion element receives distortion generated by the first energy conversion element and generates distortion,
A voltage conversion element characterized in that a voltage generated at the second terminal due to distortion of the second energy conversion element is larger than a voltage input to the first terminal . The first energy conversion element is composed of a piezoelectric member having a hysteresis characteristic with an amount of strain corresponding to the applied voltage,
2. The voltage conversion element according to claim 1, wherein the second energy conversion element is made of a piezoelectric member having an output voltage proportional to the amount of distortion . 3. The voltage conversion element according to claim 2, wherein the first energy conversion element has the same amount of distortion at a predetermined electric field strength lower than that at which the amount of distortion saturates despite having the hysteresis. .   The voltage conversion element according to claim 3, wherein the predetermined electric field intensity is zero. Voltage conversion device according to any one of claims 1 to 4 wherein the second energy conversion element is characterized in that the polarization treatment is performed. Voltage conversion device according to any one of claims 1 to 5 and the first energy conversion element and the second energy conversion element is characterized by being arranged adjacent to each other across the insulating member . Voltage conversion device according to any one of claims 1 to 6, characterized in that it has a third terminal connected to said first energy conversion element and said second energy conversion elements. 8. The voltage conversion element according to claim 7 , further comprising a circuit that supplies a predetermined voltage between the first terminal and the third terminal and extracts a voltage from the second terminal. Equipment using. Apparatus using a voltage conversion element characterized in that it consists logic element using a voltage conversion device according to any one of claims 1 to 7. Apparatus using a voltage conversion element characterized in that it consists oscillation circuit using a voltage conversion device according to any one of claims 1 to 7. The oscillation circuit has a supply means for applying a reference potential to said second terminal, said first voltage is supplied to the terminal, according to claim 10, wherein the output from the third terminal A device using the voltage conversion element. The device using the voltage conversion element according to claim 11 , wherein the oscillation circuit includes a resistor connected to the third terminal. The oscillation circuit includes a first resistor connected to the first terminal or the third terminal, and a second resistor connecting the first resistor and the second terminal. An apparatus using the voltage conversion element according to claim 11 . Comprising a voltage conversion device according to claim 7, to generate a distortion by supplying a voltage to the first energy conversion element via the third terminal to said first energy conversion elements, said first energy An apparatus using a voltage conversion element that outputs a voltage generated in the second energy conversion element in response to distortion generated in the conversion element. Comprising a voltage conversion device according to any one of claims 1 to 7, wherein the first energy conversion elements are divided into a plurality, at least one bit of the digital to each of the first energy conversion elements which are the divided An apparatus using a voltage conversion element that performs digital / analog conversion by inputting a signal and outputting a voltage generated by the second energy conversion element from the second terminal. Comprising a first voltage converter having a voltage conversion device according to any one of claims 1 to 7 and the second voltage conversion element,
The first energy conversion element in the first voltage conversion element is divided into a plurality of parts, a digital signal of at least 1 bit is input to each of the divided first energy conversion elements, and the second energy conversion element The voltage generated at the second terminal is output from the second terminal,
Connecting one of the first terminal and the second terminal of the second voltage conversion element to the second terminal of the first voltage conversion element and supplying an analog voltage to the other;
The analog / digital conversion is performed by controlling a digital signal input to the first energy conversion element of the first voltage conversion element so that the second voltage conversion element is not distorted. A device using a voltage conversion element. The voltage conversion element according to any one of claims 1 to 7 ,
Voltage control means for supplying a voltage to the first energy conversion element;
A voltage comprising: a sounding body that generates a sound based on vibration of a predetermined oscillation frequency generated in the first energy conversion element by feeding back the voltage of the second terminal to the first terminal. A device using a conversion element. The apparatus using the voltage conversion element according to claim 17, further comprising a filter that filters a voltage from the second terminal to be fed back to the first terminal. The voltage conversion element according to any one of claims 1 to 7 ,
Voltage control means for supplying a voltage to the first energy conversion element;
A voltage converter comprising: a rotating body driven by vibration of a predetermined oscillation frequency generated in the first energy conversion element by feeding back the voltage of the second terminal to the first terminal. Device using elements. 20. The apparatus using a voltage conversion element according to claim 19, further comprising means for controlling the speed of the rotating body by changing a period in which a voltage should be applied to the first energy conversion element and a duty ratio. . A voltage conversion element according to any one of claims 1 to 7 , comprising: a voltage obtained from the second energy conversion element by feeding back the voltage of the second terminal to the first terminal. An apparatus using a voltage conversion element that detects the magnitude of distortion generated in the second energy conversion element. A plurality of voltage conversion element according as the circuit elements in any one of claims 1 to 7, the voltage conversion element is between a plurality of said circuit elements and forming an integrated circuit by disposing a cushioning member Equipment using. The voltage conversion element is configured to construct a program by combining at least the characteristics related to the polarization among the information related to the polarization including the presence / absence of polarization and the direction of the polarization, and the information related to the connection between the plurality of circuit elements. The apparatus using the voltage conversion element according to claim 22 . The second device that uses a voltage conversion device according to claim 22 or 23, wherein comprising a refresh circuit for recharging the output charge of the energy conversion element.

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