JP2002130114A - Actuator device - Google Patents

Abstract

(57) [Problem] To provide a small shape memory alloy actuator having a large driving range. A movable part and a fixed part are elastic members.
Connected by The elastic member 53 has a leaf spring configuration arranged in parallel so as to regulate the main movement direction of the movable portion 51 in the movable direction 59. The shape memory alloy 54 is stretched between the movable part 51 and the fixed part 56, and the shape memory alloy 54 is contracted by electric heating to drive the movable part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator device using a shape memory alloy as a driving principle for driving small mechanical elements and optical elements.

[0002]

2. Description of the Related Art An actuator used as a means for driving a lens or the like of a small camera using a shape memory alloy as a driving principle is disclosed in, for example, Japanese Patent Laid-Open Publication
230457 are known.

FIG. 18 shows an example of a conventional shape memory alloy actuator. The main movement direction of the movable body 182 including a load requiring driving, for example, the lens 181 is regulated by the sliding surface 183 to the optical axis. The movable body 182 is
It is connected to a connecting rod 184 via a pin 185. The connecting rod 184 is connected to a fixed surface via a pin 186. Shape memory alloys 187 and 188 are attached to the connecting rod 184. When the shape memory alloy 187 is heated by flowing an electric current or the like, the shape memory alloy 187 contracts, and the connecting rod 184 rotates counterclockwise around the pin 186, whereby the movable body 182 moves along the sliding surface 183. Move to the left on the page. Conversely, when current is passed through the shape memory alloy 188 and heated, for example, the shape memory alloy 188 contracts, and the connecting rod 184 rotates clockwise around the pin 186, whereby the movable body 182 moves along the sliding surface 183. To the right of the page. The amount of repetitive deformation of the shape memory alloy needs to be about 3% of the total length in consideration of the life.
If a shape memory alloy is directly attached to 82, a sufficient drive stroke may not be obtained. Therefore, in this example, the displacement of the shape memory alloy is enlarged by using the connecting rod 184, and the movable body 182 is driven. Shape memory alloys 187, 18
The reason why the two are mounted opposite to each other is to drive one shape memory alloy while cooling the other shape memory alloy in order to increase the responsiveness of the operation. Responsiveness is impaired, but for simplicity of control,
Even if one shape memory alloy is replaced with a spring, it can be driven.

FIG. 19 shows another example of a conventional shape memory alloy actuator. Load 19 such as lens and aperture
1 is rotatably attached by a pin 193, and shape memory alloys 194 and 195 are attached to the movable body 192. When the shape memory alloy 194 is heated by flowing an electric current or the like, the shape memory alloy 194 contracts, and the movable body 192 rotates counterclockwise around the pin 193. Conversely, when the shape memory alloy 195 is heated by flowing an electric current or the like, the shape memory alloy 195 contracts, and the movable body 192 rotates clockwise around the pin 193. When an actuator based on this principle is applied to an optical system having an optical axis perpendicular to the plane of the drawing, a load 19
1 can be inserted into the optical axis or not, and optical characteristics such as focal length and aperture can be changed.

[0005]

In the conventional shape memory alloy actuator, the movement of the movable portion is often regulated by the sliding surface, and is used in an environment where lubrication cannot be sufficiently performed. In the case of manufacturing a very small actuator, the friction on the sliding surface becomes larger than other forces, and a sufficient output cannot be obtained. Further, there is a problem that a structure using a displacement expanding mechanism such as a lever as a means for expanding the displacement of the shape memory alloy is not suitable for a small actuator whose size is restricted.

[0006]

In order to solve the problem of friction on the sliding surface, the movable portion is supported by an elastic member such as a leaf spring. Further, in order to restrict the main movement direction of the movable portion on one track, the movable portion is supported by, for example, an elastic member in which one or more sets of leaf springs are arranged in parallel at intervals. As a means for driving the movable part, a thin wire or spring of a shape memory alloy is attached between the fixed part and the movable part, and the shape memory alloy is heated by an energizing or external heating means to deform the shape memory alloy, Obtain the desired drive range. Further, by using a fluid as a means for transmitting the operation of the shape memory alloy to the movable portion, it is possible to avoid occurrence of sliding friction and a lever mechanism, and to obtain a large displacement of the movable portion in a limited space.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention corresponding to the first and second claims. Movable part 1 and fixed part 2
The movable part 1 and the fixed part 2 are connected by a leaf spring-shaped elastic member 3. The elastic member 3 is thin in the movable direction 8 and easily bends in the movable direction 8. Considering only one elastic member 3, when a force is applied to the free end (movable part 1 side), the movement of the movable part 1 is accompanied by displacement and rotation, like the movement of the free end of the cantilever. become. In this embodiment, at least one set of elasticity is set so that the displacement of the movable part 1 in the direction orthogonal to the movable direction 18 and the rotation of the movable part 1 are negligible compared to the translation of the movable part 1 in the movable direction 18. The member 3 is arranged parallel to the plate thickness direction so that the movable part 1 is substantially translated with respect to the fixed part 2. A thin linear shape memory alloy 4 is stretched between the mounting portion 5 and the mounting portion 6.

The principle of driving the movable section is as follows. When the shape memory alloy 4 is heated to a temperature (for example, 100 ° C.) at which a phase change occurs due to energization, the shape memory alloy
Contracts, pulls the movable part 1 and displaces in the movable direction 9. The heating to the shape memory alloy 4 is stopped, and the temperature is set to room temperature (for example, 20
(° C.), the shape memory alloy 4 is stretched by the force of the elastic member 3, and the movable portion 1 returns to its original position.

The driving principle will be described in more detail with reference to FIG. FIG. 2 is a diagram showing the relationship between the force and the displacement of the elastic member 3 and the shape memory alloy 4, where the horizontal axis represents the displacement and the vertical axis represents the force. The sign of the displacement is positive in FIG. In FIG. 2, a characteristic 21 is a relationship between the force and the displacement of the elastic member 3, and a slope k when approximated to a straight line corresponds to a spring constant. Characteristics 22 and 23 show the relationship between the force and the displacement of the shape memory alloy 4 in the low temperature state and the high temperature state. At low temperature, the operating point is characteristic 2
The force is represented by an intersection 24 of 1 and the characteristic 22, the force at this time is F ₁ , and the displacement is d ₁ . At a high temperature, the operating point is represented by the intersection 25 of the characteristic 21 and the characteristic 23, and the force at this time is F ₂ and the displacement is d ₂ . The figure shows that the movable part 1 is displaced in the range of d ₁ -d ₂ by heating and cooling the shape memory alloy. Since the relationship between the force and the displacement due to the temperature of the shape memory alloy changes continuously between the characteristic 21 and the characteristic 23, the displacement of the movable part 1 should be continuously controlled between d ₁ and d _2. Can be. The shape memory alloy is, for example, Ti-
Ni alloys can be used and the strain can be obtained up to 10%. In consideration of the decrease in the shape memory effect due to the repeated strain, usually the strain of 3% is used. The stress required for deformation at low temperature is about 20 MPa, and the stress generated by shape recovery at high temperature is about 100 MPa. The composition and characteristic values of the shape memory alloy described here are merely examples, and any material having a shape memory effect can be used.

The shape memory alloy 4 can be mounted not only linearly between the mounting portion 5 and the mounting portion 6 but also by any mounting method as long as the movable portion 1 can be driven.

For example, in FIG.
And the mounting portion 7, and the mounting portion 6 is made of a shape memory alloy 4.
Has a role to bend. By doing so, the length of the shape memory alloy 4 can be increased, and a large displacement of the movable portion 1 can be obtained even with the same strain.

When heating is performed by energizing the shape memory alloy,
The electrical contact for supplying electricity to the shape memory alloy may be the same as the mechanical fixing portion, or may be provided separately. For example, in FIG. 1, a lead wire 8 for energization is connected to the mounting portion 7, and the other lead wire may be connected to the mounting portion 5, or the shape memory alloy 4 may be moved to the opposite surface by the movable portion. 1 and is connected to a mounting portion on the surface opposite to the mounting portion 7.

The shape of the shape memory alloy used may be a thin wire as shown in FIG. 1, a coil spring 31 as shown in FIG. 3, or a torsion coil spring 41 as shown in FIG.

An embodiment corresponding to the third aspect will be described with reference to FIG. FIG. 5 shows an embodiment having a feature that, when a thin linear shape memory alloy is used, a displacement of a movable portion larger than a displacement amount of the shape memory alloy can be obtained by the mounting method. A thin wire-shaped shape memory alloy 54 is stretched between the mounting portion 55 and the mounting portion 56, and when the shape memory alloy 54 contracts due to electric heating, the movable portion 51 is displaced in the direction regulated by the elastic member 53. At this time,
When the shape memory alloy 54 is at a certain angle θ (6
0), the shape memory alloy 5
It is possible to apply a displacement larger than the amount of strain to the movable portion 51. This will be described with reference to FIGS. FIG. 6 shows a model in which the structure of FIG. 5 is simplified. The movable part 5 regulated by the elastic member 53 in FIG.
1 can be approximated by the spring element 63 of FIG. 6 and a linear guide 68 for restricting the displacement of the movable portion to translation with one degree of freedom. Assuming that the shape memory alloy 64 at a low temperature is attached at an angle θ ₁ (66), the movable part 61 is displaced to the position of the shape memory alloy 65 at a high temperature, and the angle becomes θ ₂ (67). In FIG. 6, the displacement d (69) of the movable portion 61 is the shape memory alloy 64
Becomes larger as the mounting angle θ ₁ (66) of the lens becomes closer to 90 °. FIG. 7 is a diagram illustrating the relationship between the mounting angle θ (71) and the displacement d (72). Ε in FIG. 7 represents the strain of the shape memory alloy, and it is assumed that ε at a high temperature is constant. The fine linear shape memory alloy having a length L shrinks at high temperature to have a length of εL, and the difference between the length at low temperature and at high temperature is (1−ε).
L. FIG. 7 shows the relationship between the ratio of the displacement d of the movable part and the displacement d of the movable part as the enlargement ratio, and the relationship with the mounting angle θ. For example, 1-ε is 3% considering repeated use.
, The maximum magnification is θ = 75
°, 5.6 times. (Note that the upper limit is determined by the fact that θ at a high temperature does not exceed 90 °. From the viewpoint of the generated force, when θ is 90 °, the generated force of the shape memory alloy for deforming the elastic member becomes infinite. Therefore, it is actually a value of less than 90 °, and preferably θ = 75
° or less. The feature of the shape memory alloy is that it has a large generating force. If the enlargement ratio is about 2 to 3 times that can be obtained at the mounting angle θ = 60 ° to 70 °, it can be easily achieved by the appropriate thickness design of the elastic member. Can be driven. When the attachment angle θ of the shape memory alloy is 0 ° (the displacement direction of the movable part and the displacement direction of the shape memory alloy are parallel), the length of the shape memory alloy is 2 to obtain a displacement of two to three times. Double to three
Twice as much. On the other hand, as shown in FIG. 5, only two to three times the amount of displacement can be obtained by simply changing the shape memory alloy having the same length to the mounting angle θ = 60 ° to 70 ° because the space is limited. This is very advantageous as an actuator structure.

An embodiment corresponding to the fourth aspect will be described with reference to FIG. In FIG. 8, the plate-shaped shape memory alloy 8
1 is used as an elastic member. With such a structure, assembly is facilitated and cost is reduced. The plate-shaped shape memory alloy 81 is a bidirectional element that stores both low-temperature and high-temperature shapes, and is capable of obtaining a displacement of a movable portion by heating and cooling. Note that a part of the plate-shaped shape memory alloy 81 is an elastic member (leaf spring).
It may be. In this case, the plate-shaped shape memory alloy 81 may be a one-way element that stores the shape at the time of heating,
At low temperatures, the plate-shaped shape memory alloy 81 is deformed by the force of the elastic member. Further, apart from one or more parallel leaf spring structures, a plate-shaped shape memory alloy may be used as a drive element of the movable part.

The embodiment described above can be used as a means for adjusting optical characteristics by mounting an optical element on the movable part. FIG. 9 shows an example. A lens 91 having an optical axis in the optical axis direction 97 in the figure is mounted on the movable section 93, and an image sensor 92 is mounted on a fixed section 94 in parallel with a plane perpendicular to the optical axis. By heating the shape memory alloy 96 by energization or the like, the lens is displaced in the optical axis direction, and the distance between the imaging element and the lens can be shortened. When the heating is stopped and the shape memory alloy 96 returns to normal temperature, the lens returns to the original position. The lens displacement in the optical axis direction can be used to adjust the focus of an image formed on the image sensor through the lens. In the arrangement of FIG. 9, a distant subject is focused when the shape memory alloy 96 is not heated, and a subject close to the lens is focused during heating.
Conversely, when the shape memory alloy 96 is heated, a configuration may be adopted in which a distant subject is focused. Note that FIG.
The shape and the mounting method of the shape memory alloy shown in the above are examples, and any of the forms mentioned in the above embodiments can be applied to a means for adjusting optical characteristics, for example, a focus adjusting mechanism for imaging. it can.

Next, the configuration of a control system when the shape memory alloy actuator of the present invention is applied to a focus adjustment mechanism of a digital camera will be described. FIG. 10 shows a basic configuration of a focus adjustment mechanism using a shape memory alloy actuator. Light from a subject passes through a lens 102 and an image sensor 103
Image on top. As means for adjusting the focus in accordance with the distance to the subject, a shape memory alloy actuator 101 for displacing the lens 102 in the optical axis direction is used. The shape memory alloy actuator 101 is driven by a control signal 107 output from a control circuit 106. The automatic focus adjustment is realized by controlling the actuator so that the brightness of the image is maximized. As means for this, a luminance signal 105 of an image is input from the camera control unit 104 to the control device 106. An algorithm for driving the shape memory alloy actuator 101 so that the luminance signal 105 is maximized is built in the control device 106. Note that a mode in which the user can manually adjust the focus while viewing the image may be provided. In this case, the control device 106 ignores the luminance signal 105 and outputs a control signal 107 in accordance with a drive command signal from a user (not shown).

FIG. 11 shows a configuration in which the state variables of the shape memory alloy actuator 111 are fed back to the controller 116 for the purpose of improving the positioning accuracy of the lens 112 and speeding up the operation. Since the resistance value, which is one of the state variables of the shape memory alloy, changes according to the state of the phase change of the shape memory alloy, there is a great correlation with the displacement amount of the actuator movable part caused by the phase change. Therefore, by feeding back the resistance value to the control device, the positioning accuracy can be improved and the operation can be speeded up without providing a separate position sensor. The feedback signal 118 is a signal indicating a resistance value of the shape memory alloy or a signal indicating a voltage and a current applied to the shape memory alloy. Control device 116
Outputs a control signal 117 using a resistance value of the shape memory alloy or a conductance which is a reciprocal thereof.

The displacement of the lens may be measured by a displacement sensor. FIG. 12 is a configuration diagram in that case. A displacement sensor 128 is provided at a position suitable for measuring the displacement in the optical axis direction of the lens 112, and a signal 129 indicating the displacement is fed back to the controller 126.

The distance to the subject may be measured by a distance sensor. FIG. 13 is a configuration diagram in that case. A distance sensor 138 is provided at an appropriate position for measuring the distance to the subject, and a distance signal 139 is output from the control circuit 136.
Is input to The control circuit 136 includes a luminance signal 135 and a distance signal 13 as signals for automatically adjusting the focus.
9 or control is performed by selecting the luminance signal 135 or the distance signal 139 in accordance with the optical conditions of the subject or a command from the user.

A control system in which the functions shown in FIGS. 10 to 13 are temporarily combined can also be constructed. Also,
Since the characteristics of the shape memory alloy actuator change depending on the temperature of the use environment, a temperature sensor is provided to measure the temperature,
The control device may be provided with an algorithm for performing control under optimum conditions according to the operating temperature, or an analog circuit for performing temperature compensation may be provided in the control device.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. A cylindrical elastic member 141 is attached so that both ends thereof are in contact with the fixing portions 150 and 151. A fine wire shape memory alloy 142 is wound around the elastic member 141. Elastic member 141,
Space 1 surrounded by fixing parts 149, 150, 151
43 is a closed space except for the flow path 145. The space 143 contains gas or liquid. In this description, it is assumed that air is contained. A cylinder 148 is attached to the fixed part 151. Cylinder 1
A movable portion 147 having an outer diameter slightly smaller than its inner diameter is inserted into 48. Movable part 147, cylinder 1
48, and a space 146 surrounded by the fixing portions 151 and 149. The space 146 is a closed space except for a gap between the flow path 145, the cylinder 148, and the movable portion 147. Space 1
43 and the space 146 are connected by a flow path 145.

The operation of the movable part is as follows. The shape memory alloy 142 contracts when heated by an electric current or the like, and the elastic member 1
41 is deformed, and the volume of the space 143 is reduced. As a result, part of the air occupying the space 143 is pushed out to the space 146 through the flow path 145. Part of the air that has flowed into the space 146 leaks out through the gap between the cylinder 148 and the movable part 147, but most of the air does the work of pushing the movable part 147 forward. FIG. 14B is a diagram showing the shape memory alloy 142 at the time of contraction. Shape memory alloy 14
When the heating of 2 is stopped, the resilience of the elastic member 141 causes
The volume of the space 143 increases, air moves from the space 146 to the space 143, and the movable portion 147 moves in a direction in which the volume of the space 146 decreases. This embodiment is characterized in that the operation of the shape memory alloy is transmitted to the movable portion via air, and is a driving means capable of effectively using a limited space. By changing the shape of the elastic member 141 and the shape of the cylinder 147, the displacement enlargement ratio (the ratio of the amount of deformation of the shape memory alloy to the amount of movement of the movable portion) can be arbitrarily set. Since the actuator is driven via air, the shape memory alloy may be separated from the movable part. In order to prevent air leakage due to the gap between the cylinder 148 and the movable section 147, liquid may be injected into the gap. If the fluid filled in the space is a liquid, the surface tension can also prevent leakage. Further, an elastic member (such as a metal bellows) can be used between the cylinder 148 and the movable portion 147 to completely eliminate the leakage.

This structure can be applied to an optical system adjusting means such as a focus adjusting mechanism of a small camera. FIG. 14 shows an example in which a lens is placed in the movable part 147 and an image sensor is mounted on the fixed part 149. In addition to the optical system, it can be used for applications requiring reciprocal displacement of the movable part. Further, the form is not limited to that shown in FIG. 1, and there are a space partially surrounded by an elastic member driven by a shape memory alloy and a space in which the volume changes due to the movement of the movable part. The structure connected by the road is essential. The flow path does not need to be a small-diameter tube, and the space in which the volume changes due to the contraction of the shape memory alloy and the space in which the volume changes due to the movement of the movable portion may be one space.

In the embodiment shown in FIG. 14, when the shape memory alloy is heated by energization, the energization method uses voltage control or PWM control. In the case of voltage control, the voltage applied to the shape memory alloy is controlled, and the amount of displacement is controlled in an analog manner. In the case of PWM control, power is supplied by a pulse having a constant amplitude. The power to the shape memory alloy is controlled by the duty ratio. Since the PWM control has a relatively simple drive circuit, it is advantageous when the actuator is applied to information equipment. In addition, since the amplitude is constant, the upper limit of the power that can be supplied is determined, and damage due to excessive power supply can be prevented.

In the drive principle described above with reference to FIG. 14, it is desirable that the resistance when the fluid of the contents moves and the leakage of the fluid in the movable part be negligibly small. In the case of a structure in which fluid resistance and leakage are so large that they cannot be ignored, a driving method utilizing this can be used. This will be described with reference to FIGS. FIG. 15 is a model for explaining the operation when the fluid leaks from the movable part. The space 153 is formed by the elastic member 15 driven by the shape memory alloy.
The internal pressure changes due to the movement of 1,152. There is a solid friction component 155 between the movable part 154 and the cylinder 156 that provides resistance to relative movement. It is assumed that the cylinder 156 and the movable part 154 move relative to each other in a state where there is no fluid leakage, and it is assumed that leakage to the outside has occurred through a separately provided flow path 157. The cross-sectional area of the flow path 157 is sufficiently smaller than that of the cylinder, and a resistance is generated in proportion to the square of the flow velocity v (158) of the leakage flow. When the deformation speed of the shape memory alloy is small and the flow velocity v is small, the resistance in the flow path 157 is small,
Pressure _{P 0} of the internal pressure P and the external space 153 is almost equal. When the deformation speed of the shape memory alloy is large and the flow velocity v is large, the resistance in the flow path 157 is large, and the difference between the internal pressure P and the external pressure P ₀ increases. The driving force applied to the movable part 154 is the difference between the internal pressure P and the external pressure P ₀ , and the pressure P at which the movable part 154 starts to move has a certain threshold value due to the action of the solid friction component 155. That is, by controlling the deformation speed of the shape memory alloy,
It is possible to control whether or not 4 starts moving. This operation method has an advantage that the movable portion can be stopped at an arbitrary position even when the shape memory alloy is not energized.

FIG. 16 shows an example of the driving waveform. FIG.
16A shows the case where the movable part 154 moves leftward (direction from inside to outside), and FIG. 16B shows the case where the movable part 154 moves rightward (direction from outside to inside). Reference numeral 161 denotes a voltage waveform applied to the shape memory alloy, which is a sawtooth wave having a sharp rise. 162 indicates a pressure change in the space 153, and P ₀ indicates an external pressure,
P _L is the pressure threshold for moving the movable part to the left, P _R
Is the pressure threshold for the moving part to move to the right. The pressure P is greater than P _L just after the rise of the voltage, the movable portion moves to the left (see 163). The fall of the voltage is slow and P
Since not less than P _R, the position of the movable part of the stop voltage application is maintained. By repeating this, the movable part gradually moves to the left. When the movable part is moved to the right, a sawtooth waveform voltage having a steep fall like 164 is applied. At the time of rising, the pressure P is P
_L does not exceed (see 165). Fall of the voltage is steep, P is lower than the P _R Immediately after this, the movable portion moves to the right (see 166). By repeating this, the movable part moves to the right.

The reason why the pressure waveforms 162 and 165 are not symmetrical in the time axis and the pressure axis is that the operating speed of the shape memory alloy is not equal when the operating speed is reduced and when the operating speed is increased. This is because the heating raises the temperature by energization, and the cooling is due to heat radiation from the surface of the shape memory alloy. Generally, when driving the shape memory alloy by heating by energization, the response of the operation at the time of cooling becomes a problem compared to the time of heating,
By using a shape having a large surface area per unit volume (for example, a thin line shape), heat radiation is promoted, and the response of operation can be accelerated. In addition, responsiveness can be further improved by performing forced cooling such as blowing air on the shape memory alloy. Such a method of improving the responsiveness of the operation can be applied to all the embodiments of the present invention.

In the driving method described with reference to FIG. 15, a displacement sensor for positioning the movable portion may be used. When the displacement sensor and other measuring means are not used, if the operation of reciprocating the movable portion is performed many times, errors may be accumulated and the current position of the movable portion may not be known. As a method for solving this, a mechanical stopper for limiting the driving range of the movable portion is provided in advance, and the voltage waveform 161 is controlled.
Alternatively, in 164, if the displacement of the movable part when one waveform with a large voltage amplitude is applied to the shape memory alloy is designed so as to cover the drive range, the movable part can be reliably applied to the stopper regardless of the current position. Since this state can be set, this can be used as the initialization operation of the movable portion position.

The above-described drive voltage waveform is used for voltage control. When PWM control is performed, the voltage waveform corresponds to a temporal change in the duty ratio. All the structures and driving methods of the present invention are applicable to the case of PWM control.

An example of a method for measuring the resistance value of the shape memory alloy when performing PWM control and resistance value feedback will be described with reference to FIG. The voltage waveform 174 applied to the shape memory alloy is generated by the control signal 171. In the control signal 171, T is a PWM transport cycle;
t / T is a duty ratio. The current flowing through the shape memory alloy has a current waveform 176. The current flows during the ON time of the voltage waveform 175, and the current is almost 0 during the OFF time. The resistance value is obtained by calculating from the applied voltage and the current during the time when the voltage is ON, but the calculation timing must be matched with the PWM transport cycle, which may be inconvenient for the system. Therefore, a rising trigger signal is extracted from the control signal 171, and a trigger signal 173 is created using a delay circuit. The sample / hold circuit is held by using the trigger signal 173 to hold the voltage and current value during the ON time (see waveforms 175 and 177). The controller can calculate the resistance value and the conductance by sampling the held signal at an arbitrary timing.

[0033]

According to the present invention, the output of the shape memory alloy actuator can be increased, the size can be reduced, and the manufacturing cost can be reduced, and the actuator can be applied as a driving means for a small mechanical element or an optical element. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a shape memory alloy actuator according to first and second claims of the present invention.

FIG. 2 is a conceptual diagram showing the operation principle of the shape memory alloy actuator according to the present invention.

FIG. 3 is a configuration diagram in the case where a coil spring-shaped shape memory alloy is used in the present invention.

FIG. 4 is a configuration diagram when a shape memory alloy in the form of a torsion coil spring is used in the present invention.

FIG. 5 is a perspective view showing a configuration of a shape memory alloy actuator according to a third claim of the present invention.

FIG. 6 is a model for explaining the operation principle of the embodiment in FIG. 5;

FIG. 7 is a view for explaining the effect of the embodiment in FIG. 5;

FIG. 8 is a perspective view showing a configuration of a shape memory alloy actuator according to a fourth claim of the present invention.

FIG. 9 is an embodiment in which the shape memory alloy actuator according to the present invention is applied to an image sensor.

FIG. 10 shows an embodiment of a method for controlling a shape memory alloy actuator according to the present invention.

FIG. 11 is an embodiment of a method for controlling a shape memory alloy actuator according to the present invention.

FIG. 12 is an embodiment of a method for controlling a shape memory alloy actuator according to the present invention.

FIG. 13 is an embodiment of a method for controlling a shape memory alloy actuator according to the present invention.

FIG. 14 is a conceptual diagram showing a configuration of a shape memory alloy actuator according to a fifth aspect of the present invention.

FIG. 15 is a view for explaining one mode of the driving principle of the embodiment shown in FIG. 14;

FIG. 16 is a waveform chart for explaining the driving operation of the embodiment shown in FIG.

FIG. 17 is a diagram for explaining a method for measuring a resistance value of a shape memory alloy.

FIG. 18 shows a conventional example of a shape memory alloy actuator.

FIG. 19 is a conventional example of a shape memory alloy actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Moving part 2 ... Fixed part 3 ... Elastic member 4 ... Shape memory alloy 5, 6, 7 ... Mounting part 8 ... Lead wire 9 ... Moving direction

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) H04N 5/225 G03B 3/00 A F term (reference) 2H011 AA03 CA12 2H044 BE01 BE06 BE10 DA01 DB00 DC02 DD00 2H051 AA00 FA01 5C022 AA13 AB12 AB21 AB44 AC42 AC54

Claims (5)

[Claims] A movable part and a fixed part, wherein the movable part is supported by the fixed part by an elastic member, and the movable part is capable of deforming the elastic member between the fixed part and the movable part. The shape memory alloy is installed in the actuator device. 2. The actuator device according to claim 1, wherein an elastic member is attached so that a main movement direction of the movable portion is a reciprocating motion along one orbit. 3. A shape memory alloy, wherein a deformation direction of the shape memory alloy is attached at an angle to a movement direction of the movable portion, and a displacement of the movable portion is larger than a deformation amount of the shape memory alloy. The actuator device according to claim 1. 4. The plate memory device according to claim 1, wherein a plate-shaped shape memory alloy is used, and said shape memory alloy also has a function of regulating a movement direction of said movable portion. Actuator device. 5. An elastic member driven by a shape memory alloy, a space surrounded by the elastic member, a fixed portion, and a movable portion, and a fluid filled in the space, the deformation being caused by deformation of the shape memory alloy. Due to the deformation of the elastic member,
An actuator device, wherein the movement of the fluid occurs to displace the movable portion.