WO2011114435A1

WO2011114435A1 - Driving device using polymer actuator elements

Info

Publication number: WO2011114435A1
Application number: PCT/JP2010/054420
Authority: WO
Inventors: 高橋　功; 宣明芳賀
Original assignee: アルプス電気株式会社
Priority date: 2010-03-16
Filing date: 2010-03-16
Publication date: 2011-09-22
Also published as: JPWO2011114435A1; JP5466757B2

Abstract

Disclosed is a more compact, slimmer, and lower-cost driving device which comprises polymer actuator elements exhibiting superior heat-generation control characteristics and which can efficiently warm the polymer actuator elements. The driving device comprises an electrolyte layer, electrode layers provided on both surfaces of the electrolyte layer in the thickness direction, and a polymer actuator element that deforms when a voltage is applied between said electrode layers. When an AC voltage (E) with a higher frequency than drive voltage (C) supplied to the polymer actuator element is superposed on said drive voltage, a drive current flows to the electrode layers and the polymer actuator element is warmed by Joule self-heating.

Description

Drive device using polymer actuator element

The present invention relates to a drive device having a polymer actuator element that bends and deforms when a voltage is applied to a pair of electrode layers, and more particularly to a structure for improving temperature characteristics of the polymer actuator element.

The polymer actuator element includes, for example, an electrolyte layer and a pair of electrode layers provided on both sides in the thickness direction of the electrolyte layer as shown in Patent Document 1. When a voltage is applied between the pair of electrode layers on the base end side that is the fixed end, the tip end that is the free end is bent and deformed.

Generally, a polymer actuator element has temperature characteristics, and the displacement amount and generated force of the polymer actuator element vary depending on the use environment temperature. In particular, the actuator characteristics are likely to deteriorate under a low temperature environment.

Regarding the temperature characteristics of the above-described element, in the invention described in Patent Document 2, in order to obtain a stable operation in a low temperature environment, a polymer actuator element is disposed on the image sensor side, and the image sensor at the time of driving is arranged. A structure in which the polymer actuator element is warmed by the heat from is disclosed.

JP 2009-77578 A JP 2006-293006 A

However, in the structure shown in Patent Document 2, the imaging element is separated from the polymer actuator element. A structure in which a heat radiating plate is attached to the imaging element and a heat generating part is brought close to the polymer actuator element is also disclosed, but cannot be brought into contact with each other, so that it is difficult to efficiently warm the element. Further, the structure shown in Patent Document 2 cannot be applied to a drive device that requires an image sensor and is not provided with an image sensor in the first place. Or in the structure which does not have an image pick-up element shown in patent document 2, if a new heat generating apparatus is used in order to warm a polymer actuator element, it will become high-cost. Further, in the structure of Patent Document 2, the polymer actuator element can be warmed only when the image sensor is driven, and further, the polymer actuator element is warmed even when it is not necessary to be warmed, resulting in poor controllability. Yes.

Accordingly, the present invention solves the above-described conventional problems, and can provide a driving apparatus using a polymer actuator element that can efficiently warm a polymer actuator element at low cost and has excellent controllability to heat generation. It is intended to provide.

The drive device having the polymer actuator element according to the present invention,
A polymer actuator element comprising an electrolyte layer and electrode layers provided on both surfaces in the thickness direction of the electrolyte layer, and deformed when a voltage is applied between the electrode layers;
A drive unit having a controller for applying a drive voltage to the polymer actuator element,
The control unit can apply an AC voltage to the polymer actuator element, and the control unit applies the AC voltage according to a state of the polymer actuator element.

As described above, the control unit can apply an AC voltage to the polymer actuator element as necessary. When the AC voltage is applied, a current flows through the electrode layer, and the polymer actuator element is warmed by self-heating by Joule heat. It is done. And in this invention, the characteristic at the time of low temperature can be improved, or the bias | inclination of ion can be removed easily. Further, in the present invention, a controller capable of applying an alternating voltage is connected to the element, and there is no need to change the layer structure of the polymer actuator element from the conventional one. Further, there is no need to provide a separate heat generating device. For this reason, the drive device can be reduced in size, thickness, and cost. In addition, it is possible to warm the actuator element efficiently because it is a structure that uses the self-heating of the element itself, and since there is no change in the element structure, there is no factor such as characteristic deterioration due to structural change or deterioration in characteristic stability, Therefore, according to the present invention, it is possible to effectively improve the actuator characteristics of the polymer actuator element particularly at low temperature operation.

In the present invention, it is preferable that the controller applies the AC voltage when a temperature around the polymer actuator element or the polymer actuator element is lower than a predetermined temperature.

In the present invention, it is preferable that the controller applies the AC voltage when a current value flowing through the polymer actuator element is smaller than a predetermined value. Since the drive current becomes small at low temperatures, the characteristics at low temperature can be effectively improved by applying an alternating current when the drive current becomes smaller than a predetermined value.

In the present invention, the control unit is provided with a monitor unit capable of detecting at least one of an environmental temperature change or an information change from the polymer actuator element based on the environmental temperature change, and the monitor unit It is preferable to determine whether or not the AC voltage is superimposed on the basis of the detection result from. For example, when the monitor unit detects that the environmental temperature change has become equal to or lower than a predetermined temperature, control can be performed so that alternating voltage is superimposed. Alternatively, when the environmental temperature is low, the drive current flowing through the polymer actuator element is reduced and the element displacement is reduced. Therefore, when the monitor unit detects that the drive current or the element displacement is below a predetermined value. In addition, it is possible to control so that alternating voltage is superimposed. As described above, in the present invention, the timing of superimposing the AC voltage can be set finely, and the controllability with respect to heat generation can be improved more effectively.

In the present invention, the control unit is provided with a monitor unit capable of detecting at least one of an environmental temperature change or an information change from the polymer actuator element based on the environmental temperature change, and the monitor unit It is preferable that the superimposed waveform of the AC voltage is controlled based on the detection result from. The control of the superimposed waveform in the present invention means controlling the frequency of AC voltage, symmetry (symmetry) with respect to voltage and drive voltage, waveform shape (rectangular wave, sine wave, sawtooth wave, triangular wave, etc.), and the like. . And in this invention, based on the detection result from a monitor part, the superimposed waveform of alternating voltage can be set finely, and the controllability with respect to heat_generation | fever can be improved more effectively.

In the present invention, it is preferable that the monitor unit detects a current flowing through the polymer actuator element.

In the present invention, it is preferable that the AC voltage is applied with being superimposed on the drive voltage with an amplitude smaller than the drive voltage. By superimposing a small alternating voltage, the influence on the operation of the polymer actuator element can be reduced.

In the present invention, the maximum voltage value of the AC voltage and the absolute value of the minimum voltage value can be different. Thereby, for example, it is possible to avoid that the maximum value of the voltage in which the AC voltage and the driving voltage are superimposed exceeds the driving voltage, and it is possible to prevent deterioration of the polymer actuator element. *

In the present invention, it is preferable that the AC voltage can be applied to the polymer actuator when no driving voltage is applied to the polymer actuator element.

As a result, the polymer actuator element can be efficiently warmed even when the polymer actuator element is not driven, and the polymer actuator element can be smoothly driven during the subsequent driving, particularly in a low temperature environment. it can.

In the present invention, the polymer actuator element can be warmed efficiently at low cost. In particular, it is possible to effectively improve the actuator characteristics of the polymer actuator element at low temperature operation. Furthermore, according to the present invention, the controllability against heat generation can be effectively improved.

(A) is a partial cross-sectional view when the polymer actuator element in the present embodiment is not driven, (b) is a partial cross-sectional view showing a state where the polymer actuator element is curved, (A) is a schematic diagram showing an example of a voltage waveform applied between electrode layers of the polymer actuator element, (b) is a schematic diagram showing an example of a current waveform flowing through the polymer actuator element 32, Partial enlarged schematic view showing another example of the voltage waveform applied between the electrode layers of the polymer actuator element, Block diagram of a control unit provided in the drive device of the present embodiment, The fragmentary sectional view of the dot display device to which the drive device which has a polymer actuator element of this embodiment is applied.

FIG. 1 is a partial cross-sectional view of a polymer actuator element that constitutes the drive device of this embodiment. FIG. 1B schematically shows a control unit connected to the polymer actuator element together with the polymer actuator element.

In the present embodiment, a drive device having a polymer actuator element has at least a polymer actuator element and an electric system including a control unit for driving the polymer actuator element. First, the structure of the polymer actuator element will be described with reference to FIG.

As shown in FIG. 1A, the polymer actuator element 32 in the present embodiment includes an electrolyte layer 33, upper electrode layers 34 formed on both surfaces in the thickness direction (Z) of the electrolyte layer 33, and A lower electrode layer 35 is provided.

For example, the polymer actuator element 32 according to the embodiment of the present invention includes an electrolyte layer 33 having an ionic liquid and a base polymer, an upper electrode layer 34 and a lower electrode having a conductive filler such as carbon nanotubes, an ionic liquid and a base polymer. And a layer 35. The upper electrode layer 34 is formed on the upper surface side of the electrolyte layer 33 in the figure, and the lower electrode layer 35 is formed on the lower surface side of the electrolyte layer 33 in the figure.

As the base polymer, polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA) or the like can be presented. In this specific example, since the ion exchange resin is not included in the electrolyte layer 33, both the cation and the anion are freely movable.

The electrolyte layer 33 may include an ion exchange resin and a polar organic solvent containing a salt or a liquid organic compound that is an ionic liquid. At this time, the ion exchange resin is, for example, a cation exchange resin. As a result, the anion is fixed and the cation can move freely. As the cation exchange resin, a resin obtained by introducing a functional group such as a sulfonic acid group or a carboxyl group into a resin such as polyethylene, polystyrene, or fluororesin can be preferably used.

The base end portion 36 of the polymer actuator element 32 is a fixed end portion, and the base end portion 36 of the polymer actuator element 32 is fixedly supported by a fixed support portion 38. As shown in FIG. 1, for example, the polymer actuator element 32 is cantilevered. When a drive voltage is applied between the electrode layers 34 and 35 on both sides, as shown in FIG. 1B, a swelling difference occurs above and below the electrolyte layer 33 due to ion movement in the electrolyte layer 33 and the bending stress is increased. It is generated and the distal end portion 37 which is the free end portion of the polymer actuator element 32 can be bent and deformed. The principle that the difference in swelling between electrodes due to ion transfer is generally not unambiguous, but one of the typical principle factors is that there is a difference in swelling due to the difference in ionic radius between cation and anion. It is known.

1 is preferably a connection part that is electrically connected to the electrode layers 34 and 35. Or the structure by which a wiring board etc. are arrange | positioned between the fixed support part 38 and each

electrode layer

34 and 35 may be sufficient.

For example, a control unit 80 including a drive circuit 60 shown in FIG. 1B is connected to the base end portion 36 of the polymer actuator element 32. The control unit 80 (drive circuit 60) can apply a drive voltage to the polymer actuator element 32 and further includes an oscillator (OSC) so that an alternating voltage can be superimposed on the drive voltage.

2A shows an example of a voltage waveform applied between the electrode layers 34 and 35 of the polymer actuator element 32, and FIG. 2B shows a current waveform flowing through the polymer actuator element 32. As shown in FIG. In the non-driving state A of the polymer actuator element 32 shown in FIG. 2A, no voltage is applied between the electrode layers 34 and 35, and in the driving state B of the polymer actuator element 32, a driving voltage is applied between the electrode layers 34 and 35. Apply C.

The polymer actuator element 32 in the present embodiment is a capacitive load actuator, and the drive current D flowing through the polymer actuator element 32 shown in FIG. 2B behaves in the same manner as a general capacitor. When the drive voltage C is raised by, for example, a rectangular wave as shown in FIG. 2A, the drive current D becomes a differential waveform, and a large current is generated at the rising portion of the drive voltage C as shown in FIG. Flowing and charging begins. Thereafter, the drive current D rapidly decreases and eventually the drive current D becomes smaller due to full charge.

As described above, each of the electrode layers 34 and 35 in the present embodiment has a configuration including a conductive filler such as a carbon nanotube, and can generate heat by Joule heat by passing an electric current.

Therefore, in this embodiment, as shown in FIG. 2A, an AC voltage E having a frequency higher than that of the drive voltage C is applied to the drive voltage C by the drive circuit 60 including the oscillator shown in FIG. Superposition is possible. The AC voltage is applied according to the state of the polymer actuator element 32. Since the AC voltage E is a voltage having an amplitude centered on 0 V, the center voltage I having a waveform superimposed on the drive voltage C coincides with the drive voltage C. The driving voltage C is a main voltage for bending and deforming the polymer actuator element 32 as shown in FIG. 1B, and indicates a voltage necessary for driving. Specifically, as shown in FIG. 2A, it indicates the voltage level at a linear portion after the voltage rises from the time of non-application of the voltage. In addition, although the example which provided the linear part for illustration so that it may be understood easily is shown, you may apply alternating current from the beginning.

In the present embodiment, as shown in FIG. 2A, the AC voltage E is superimposed on the drive voltage C, whereby the current F is repeatedly applied to the electrode layers 34 and 35 as shown in FIG. It can flow. Therefore, the electrode layers 34 and 35 can be heated by Joule heat. When the current component due to the drive voltage decreases and the current component due to the AC voltage becomes relatively large, the current F becomes close to the AC current and may temporarily become a negative value.

AC voltage E is set to a frequency higher than drive voltage C. At this time, the AC voltage E is set to a frequency or voltage that does not change in the displacement of the polymer actuator element 32 itself due to superimposition on the drive voltage C, or falls within the allowable fluctuation according to the purpose of use. .

For example, the drive device (see FIG. 5) using the polymer actuator element 32 of the present embodiment is used to press the protruding member 31 by direct current driving (DC driving) the polymer actuator element 32 as described later. In such a case, the frequency of the superimposed AC voltage E can be set to about 1 to several hundred Hz (more specifically, about 1 to 100 Hz).

Further, as shown in FIG. 2A, by setting the amplitude of the AC voltage E to be smaller than the drive voltage C, the superimposed maximum voltage value G becomes too high with respect to the drive voltage C, and the polymer actuator element. It can be avoided that 32 deteriorates. Although depending on the frequency, the AC voltage E may be several tens of mV to several tens of mV with respect to the driving voltage C of 1 to 3V. Thereby, the polymer actuator element 32 can be efficiently warmed and the polymer actuator element 32 can be driven stably.

As described above, in the present embodiment, if necessary, the polymer actuator element 32 can cause the current F to flow through the electrode layers 34 and 35 by superimposing the AC voltage E on the drive voltage C. Can be warmed by self-heating. In the present embodiment, there is a need to change the layer structure / shape of the polymer actuator element 32 from the conventional one only by changing the circuit structure of the drive circuit 60 constituting the control unit 80 connected to the polymer actuator element 32. Absent. For this reason, compared with the case where a heat generating device is used separately, the drive device provided with the polymer actuator element 32 can be reduced in size, thickness, and cost. In addition, since the self-heating of the element itself is used, the actuator element 32 can be efficiently warmed, and since the element structure is not changed, there is no factor such as deterioration of characteristics due to structural changes or deterioration of characteristics stability. . Therefore, according to the present embodiment, it is possible to effectively improve the actuator characteristics of the polymer actuator element 32 particularly at low temperature operation.

In FIG. 2A, the center voltage value I between the maximum voltage value G and the minimum voltage value H of the AC voltage E substantially matches the drive voltage C. Therefore, in FIG. 2A, the alternating voltage E can be superimposed on the symmetrical waveform with respect to the driving voltage C. When the frequency of the superimposed AC voltage E is sufficiently higher than the ion movement speed in the electrolyte layer 33, the maximum voltage value of the AC voltage E is applied at a voltage exceeding the upper limit voltage that can be applied to the polymer actuator element 32. In this case, the alternating voltage E having a symmetrical waveform as described above is excellent in voltage controllability, and the actuator characteristics of the polymer actuator element 32 are less varied and the stability of the characteristics is improved. Is the most efficient.

Alternatively, an asymmetrical AC voltage can be superimposed on the driving voltage C as shown in FIG. For example, if the amplitude of the AC voltage is increased too much in order to obtain a large amount of heat generation, the maximum voltage value G may become too high and the polymer actuator element 32 may gradually deteriorate. By applying the voltage so that the maximum voltage value G is not so high and the minimum voltage value H is low, that is, the maximum voltage value (GC) and the minimum voltage value (HC) of the AC voltage E are reduced. By applying asymmetrical AC voltages having different absolute values, it is possible to generate heat by flowing a sufficient current. At this time, by appropriately controlling the waveform, the average applied voltage can be set to the drive voltage C, and a current can flow without affecting the displacement. As a result, the heat generation effect can be improved more effectively, and it is possible to effectively improve the actuator characteristics particularly in a low temperature environment.

The waveform of the AC voltage E may be a triangular wave, a sine wave or the like as shown in FIG. 2A, or may be a rectangular wave as shown in FIG. The waveform shape is not particularly limited, but the waveform shape can be regulated by a waveform control unit 84 constituting the control unit 80 described later.

FIG. 4 shows a preferred configuration of the connecting portion 80 connected to the polymer actuator element 32. As shown in FIG. 4, the control unit 80 includes a monitor unit 81, a determination processing unit 82, and a drive circuit 60. The determination processing unit 82 determines whether or not to perform AC voltage superimposition based on the detection result from the monitor unit 81, and the AC voltage superimposed waveform based on the detection signal from the monitor unit 81. And a waveform control unit 84 for controlling the waveform for controlling.

As shown in FIG. 4, the polymer actuator element 32 is connected to a monitor unit 81 and a drive circuit 60.

The superposition of the AC voltage E on the drive voltage C in the present embodiment is performed, for example, when the environmental temperature becomes a certain low temperature. When the polymer actuator element 32 is at a low temperature, it becomes difficult for the drive current to flow between the electrode layers 34 and 35, so the monitor unit 81 detects a change in the drive current (peak current) of the polymer actuator element 32. Based on the detection result of the monitor unit 81, the switching unit 83 of the determination processing unit 82 determines whether or not the AC voltage E is superimposed on the drive voltage C shown in FIG. When the switching unit 83 determines that the alternating voltage E is to be superimposed, the driving circuit 60 causes the alternating voltage E to be superimposed on the driving voltage C and applied to the polymer actuator element 32. Thereby, the polymer actuator element 32 is warmed. Alternatively, when the switching unit 83 determines not to superimpose the AC voltage E, the drive circuit 60 applies the drive voltage C to the polymer actuator element 32 without superimposing the AC voltage E. In such a case, the polymer actuator element 32 is not warmed. As described above, in the present embodiment, the controller 80 can switch on / off the superposition of the AC voltage E depending on whether the polymer actuator element 32 needs to be warmed or not. It becomes possible to keep the element 32 in an optimal state.

Further, based on the detection result of the monitor unit 81, the waveform control unit 84 can determine whether or not to control the superimposed waveform of the AC voltage E. The control of the superimposed waveform includes symmetry with respect to the frequency and voltage of the AC voltage E and the driving voltage C (symmetry; see FIGS. 2A and 3), waveform shape (rectangular wave, sine wave, sawtooth wave, triangular wave, etc.); 2 (a), FIG. 3) and the like are controlled. Thereby, based on the detection result of the monitor part 81, the emitted-heat amount etc. can be adjusted and it becomes possible to keep the polymer actuator element 32 in the optimal state.

In the present embodiment, the monitor unit 81 can also monitor the amount of displacement of the polymer actuator element 32 to switch on / off of the superposition of the AC voltage E and adjust the superposition waveform. If the temperature is low, the amount of displacement becomes smaller than a predetermined value even if a predetermined drive voltage C is applied to the polymer actuator element 32. Therefore, the amount of displacement of the polymer actuator element 32 is detected by the monitor unit 81, and on the basis of the detection result, the control unit 80 switches on / off the superposition of the AC voltage E and adjusts the superposition waveform. Is possible.

In the present embodiment, the monitor unit 81 is connected to a thermosensitive element (thermometer) 85, and when the monitor unit 81 detects an external environmental temperature, the control unit 80 turns on the superposition of the AC voltage E. It is also possible to switch on / off and adjust the superimposed waveform.

As described above, in the present embodiment, switching of on / off of the superposition of the alternating voltage E and adjustment of the superposition waveform are performed by changing the environmental temperature or changing the information from the polymer actuator element 32 (displacement amount) Or the drive current) can be detected by the monitor unit 81, and can be set finely based on the detection result. As described above, in the present embodiment, it is possible to more effectively improve the controllability for heat generation.

The thermal element 85 and the monitor unit 81, the polymer actuator element 32 and the monitor unit 81 may both be connected or may be connected to only one of them.

In the present embodiment, the main purpose of warming the polymer actuator element 32 is to suppress a decrease in actuator characteristics in a low temperature environment and improve the actuator characteristics. For example, the polymer actuator element is also used in a room temperature environment. By warming 32, the actuator characteristics can be further improved. The AC voltage E is superimposed on the drive voltage C when the environmental temperature change or the information change from the polymer actuator element 32 based on the environmental temperature change becomes, and how the superimposed waveform is changed. It can be changed or adjusted as appropriate depending on the setting for the determination processing unit 82. When it is desired to further improve the actuator characteristics not only when the ambient temperature is low but also at room temperature or the like, the polymer actuator element 32 is heated by heating the electrode layers 34 and 35 by superimposing AC waveforms. It is possible to set. Also, when driving in the opposite direction in order to eliminate the distortion of the polymer actuator element 32 caused by continuing driving in one direction, it is better to raise the temperature in order to smooth the movement of ions and soften the polymer. Good. In such a case, the alternating waveform can be superimposed.

In the present embodiment, as shown in FIG. 2A, an AC voltage J can be applied in the non-driven state A of the polymer actuator element 32 in which no voltage is applied between the electrode layers 34 and 35. It is. Thereby, even when the polymer actuator element 32 is not driven, the element can be warmed, and the polymer actuator element can be smoothly driven at the time of subsequent driving, particularly in a low temperature environment.

The AC voltage J is set to a frequency or voltage at which the polymer actuator element 32 does not displace even when the AC voltage J is applied, or even if the polymer actuator element 32 is displaced, the amount of displacement is within the allowable range for the purpose of use in the drive device. Is done.

As shown in FIG. 2A, the AC voltage E is set so as to be superposed on the drive voltage C, and the control unit 80 is set so that the AC voltage J can be applied even in the non-drive state A. It is also possible to control the AC voltage J to be applied only in the non-driving state A.

FIG. 5 shows a specific application example of the driving device having the polymer actuator element in the present embodiment.

FIG. 5 shows a partial longitudinal sectional view of the dot display device 1. The dot display device 1 is used, for example, as a braille cell that gives information to a visually impaired person. FIG. 5 is a vertical cross-sectional view showing a portion of one dot out of braille generally composed of six dots.

As shown in FIG. 5, in the dot display device 1, a lower case 10 and an upper case 20 are overlapped to form a thin casing. As shown in FIG. 5, predetermined spaces (deformable regions) 10 b and 20 b are formed between the lower case 10 and the upper case 20.

Then, as shown in FIG. 5, a polymer actuator element 32 is disposed in the

spaces

10b and 20b.

The base end portion 36 of the polymer actuator element 32 is sandwiched and fixed by the upper pressing portion 25 formed on the upper case 20 and the lower pressing portion 13 provided on the lower case 10. The lower pressing portion 13 is integrally connected to the elastic portion 12.

Further, as shown in FIG. 5, an upper wiring board 50 is provided between the base end portion 36 and the upper pressing portion 25. The upper wiring board 50 and the upper electrode layer 34 (see FIG. 1 and the like) of the polymer actuator element 32 are electrically connected. A lower wiring board 40 is provided between the base end portion 36 and the lower pressing portion 13. The lower wiring board 40 and the lower electrode layer 35 (see FIG. 1 and the like) of the polymer actuator element 32 are electrically connected.

As shown in FIG. 5, a hole 21 is formed in the upper case 20, and a protruding member 31 is provided in the hole 21. The protruding member 31 is a contacted portion 31a having a curved surface at the distal end facing the Z1 direction as the protruding direction, and a pressed portion 31b receiving the protruding pressing force at the proximal end facing in the Z2 direction as the retracting direction.

The solid-line polymer actuator element 32 shown in FIG. At this time, for example, the distal end portion 37 which is a free end of the polymer actuator element 32 is in a state of being in contact with the pressed portion 31 b of the protruding member 31.

As shown in FIG. 5, a voltage is applied to the electrode layers 34 and 35 of the polymer actuator element 32 to bend and deform the tip portion 37 of the polymer actuator element 32 upward, and the protruding member 31 is pressed to a dotted line. It can be moved upward as shown.

According to the present embodiment, the polymer actuator element 32 is warmed by self-heating of the polymer actuator element 32 when the polymer actuator element 32 is driven, when it is not driven, or when it is driven and not driven. In particular, the actuator characteristics in a low temperature environment can be improved. In the present embodiment, the heat generating device is not provided separately, but the self-heating of the polymer actuator element 32 is used as described above, so that the dot display device 1 can be reduced in size, thickness, and cost. In addition, since the electrode layers 34 and 35 constituting the polymer actuator element 32 are used as a heating element, the entire polymer actuator element 32 can be efficiently warmed.

Further, in the present embodiment, the control unit 80 shown in FIG. 4 is provided in the dot display device 1, and the polymer actuator element 32 can self-heat only when necessary, and the amount of generated heat is also adjusted by adjusting the superimposed waveform. Therefore, the dot display device 1 having excellent controllability against heat generation can be obtained.

The drive device having the polymer actuator element 32 of the present embodiment can be applied to other than the braille dot display device 1.

A Non-driving state B Driving state C Driving voltage D Driving current E, J AC voltage F Current 1 Dot display device 10

Lower case

10b, 20b Space (deformable region)
20 Upper case 31 Projecting member 31b Pressed portion 32 Polymer actuator element 33

Electrolyte layer

34, 35 Electrode layer 36 Base end portion 37 Tip end portion 40, 50 Wiring board 60 Drive circuit 80 Control unit 81 Monitor unit 82 Judgment processing unit 83 Switching 84 Waveform controller 85 Thermal element

Claims

A polymer actuator element comprising an electrolyte layer and electrode layers provided on both surfaces in the thickness direction of the electrolyte layer, and deformed when a voltage is applied between the electrode layers;
A drive unit having a controller for applying a drive voltage to the polymer actuator element,
The control unit can apply an AC voltage to the polymer actuator element, and the control unit applies the AC voltage according to a state of the polymer actuator element.
The driving device according to claim 1, wherein the controller applies the AC voltage when a temperature around the polymer actuator element or the polymer actuator element is lower than a predetermined temperature.
The driving device according to claim 1, wherein the control unit applies the AC voltage when a current value flowing through the polymer actuator element is smaller than a predetermined value.
In the control unit, a monitor unit capable of detecting at least one of an environmental temperature change or an information change from the polymer actuator element based on the environmental temperature change is provided, and a detection result from the monitor unit is displayed. The drive device according to claim 1, wherein the presence or absence of superposition of the AC voltage is determined based on the basis.
The control unit is provided with a monitor unit capable of detecting at least one of an environmental temperature change or an information change from the polymer actuator element based on the environmental temperature change, and based on a detection result from the monitor unit. The drive device according to claim 1, wherein a superimposed waveform of the AC voltage is controlled.
The drive unit according to claim 4 or 5, wherein the monitor unit detects a current flowing through the polymer actuator element.
The drive device according to any one of claims 1 to 6, wherein the AC voltage is applied with being superimposed on the drive voltage with an amplitude smaller than the drive voltage.
The driving device according to any one of claims 1 to 7, wherein an absolute value of the maximum voltage value and the minimum voltage value of the AC voltage is different.
The drive device according to any one of claims 1 to 8, wherein the AC voltage can be applied to the polymer actuator when no drive voltage is applied to the polymer actuator element.