JP4935641B2 - Drive device using shape memory alloy - Google Patents

Description

  The present invention relates to a drive device for driving a small mechanical element, and more particularly to a drive device using a shape memory alloy suitable for moving a lens of an optical device in an optical axis direction.

  Conventionally, for the purpose of correcting spherical aberration in an optical system for optical pickup and adjusting focus in a photographing optical system of a camera, a part of the optical system is made movable and driven by an actuator. Conventionally, examples of the driving means include a combination of a rotary motor, a speed reduction mechanism, a direction changing mechanism, and the like, and an example of linear movement by a linear motor.

  Further, in a micro lens unit represented by a recent portable camera or the like, the mechanism using the rotary motor and the speed reduction mechanism described above has many elements and a large size. Further, in a drive mechanism using a rear motor using an ultrasonic motor or the like, the size of the optical axis in the projected area direction can be reduced, but a predetermined size is required in the optical axis direction and cannot be reduced.

  Further, since these drive devices have a low output energy density, and the size of the device decreases, the output decreases accordingly. Therefore, there has been a clear limit to downsizing the lens drive device.

  For this reason, development of an actuator using a shape memory alloy, which is known to be small but have a high energy density, has been underway. Moreover, the linear drive device using the length variation of several% (for example, 3-5%) of the full length using a string-like shape memory alloy (shape memory alloy wire) can be configured.

  When energized between both ends of the shape memory alloy wire, it is heated by Joule heat that generates heat, and contracts to the memory length when it reaches a predetermined temperature (heating shrinkage process). On the other hand, when the energization is cut off from this high temperature state, it is cooled to a predetermined temperature or less by heat radiation, released from the shape memory state, and extended by an elastic force such as a separately provided bias spring (cooling extension process).

  The lens unit can be moved in the optical axis direction by utilizing the above-described heat shrinkage process and cooling extension process of the shape memory alloy wire. In addition, in order to move straight in the optical axis direction, a configuration that moves along a slide guide shaft extending in the movement direction is generally used.

  However, in the system in which the lens unit is driven along the slide guide shaft, an inclination (tilt) is generated due to a fitting clearance (clearance) between the slide guide shaft and a sleeve through which the guide shaft is inserted.

  Furthermore, when the lens unit is reciprocated through the slide guide shaft, the tilt direction may be reversed between forward and backward. In addition, since the positional deviation of the stop position also becomes a problem when moving the lens, in the spherical aberration correction method of the optical pickup device having a mechanism for changing the lens interval for correcting the aberration, An aberration correction method in which the rotational speed of the drive motor is controlled so as to correct the tilt has already been disclosed (for example, see Patent Document 1).

In order to form a drive mechanism with good responsiveness using a shape memory alloy, it is preferable to reduce the friction of the drive system as much as possible, and it is important to combine a guide mechanism that allows the lens to move straight with low friction. ing. For this purpose, an actuator device (driving device) that moves a lens or the like using a parallel link mechanism composed of a pair of opposed parallel leaf springs and a shape memory alloy, which is known as a guide mechanism that enables linear movement with low friction. ) Has already been published (see, for example, Patent Document 2).
JP 2004-335022 A JP 2002-130114 A

  In a lens driving device that reciprocates by sliding the sleeve along the slide guide shaft, the amount of tilt can be reduced by increasing the sleeve length. However, if the sleeve length is long, the apparatus becomes large, which is disadvantageous for downsizing the apparatus. Further, when the sleeve length is shortened, the tilt amount with respect to the clearance amount becomes large. Therefore, unless the clearance accuracy is increased, the desired tilt amount cannot be suppressed.

  As described above, when miniaturization is required, it is necessary to improve accuracy, and it is difficult to achieve both miniaturization and accuracy. Further, in the method of correcting the positional deviation and the tilt by controlling the rotation speed of the drive motor, the control becomes complicated and the control time becomes long.

  In a parallel link mechanism composed of a pair of parallel leaf springs, the leaf spring needs to bend twice in the length direction in order for the driven body (for example, the lens unit) to move in parallel while maintaining the posture. Yes (referred to as the secondary mode of the string). However, since the energy stored due to the displacement is smaller when there is one inflection (referred to as the first mode of the string), the parallel leaf spring tends to have this shape as much as possible. Therefore, it is difficult to suppress the tilt particularly in the case of a cantilevered parallel leaf spring.

  The actuator device described in Patent Document 2 also uses a cantilevered parallel leaf spring, and when the shape memory alloy wire is heated and contracted, the parallel leaf spring generates a primary mode of the string and flexes. It is difficult to maintain a stable linear movement of the lens unit due to tilt.

  In general, in order to obtain a required movement amount using a shape memory alloy wire whose expansion and contraction amount with respect to the entire length is several percent, a method of arranging the shape memory alloy wire so as to be inclined with respect to the movement direction can be considered. However, when the shape memory alloy wire is disposed obliquely at a predetermined angle and contracted, a component force acts in a direction perpendicular to the moving direction, and the leaf spring is bent by this component force, resulting in a change in tilt amount. Produce.

  Therefore, in view of the above problems, the present invention provides a shape memory alloy that enables downsizing of the apparatus and also suppresses the occurrence of tilt and stably moves a small driven body such as a lens in a straight line. An object is to provide a drive device used.

In order to achieve the above object, the present invention provides a lens unit comprising a lens, a lens part comprising a holder for holding the lens, a sleeve provided on one side of the lens part, and a rotation restricting guide part provided on the other side. A slide guide shaft that passes through the sleeve and has a shaft end fixed to the fixed portion and slidably supports the lens unit in the optical axis direction, and engages with the rotation restriction guide portion to engage the optical axis of the lens unit. A driving device for obtaining a driving force to be slid through a shape memory alloy wire provided between the fixed portion and the lens unit. The suspension is provided between the suspension provided on the outside of the sleeve and the fixed terminal provided on the fixed portion, and the fixed terminal is disposed in front of the slide direction and the suspension. Provided at a position displaced in the direction of the rotation regulating guide on the other end side, provided so that the shape memory alloy wire obliquely crosses the slide guide shaft, and a driving tension exerted when the shape memory alloy wire contracts The urging direction is set to a direction inclined by a predetermined angle from the optical axis so as to generate a pressing force for pressing the sleeve against the slide guide shaft .

  With the above configuration, the contraction force of the shape memory alloy wire that drives the lens unit in the optical axis direction can be used as a pressing force that presses the sleeve against the slide guide shaft, and the tilt of the lens unit can be suppressed. It is possible to obtain a drive device that enables linear movement and stable optical performance.

  According to the present invention, in the drive device configured as described above, an intermediate portion of the shape memory alloy wire is stretched over the suspension portion, and both ends of the folded shape memory alloy wire are fixed to two separate fixed terminal portions, respectively. In addition, the two fixed terminal portions are provided at substantially equal distances from the suspension portion, respectively.

  With the above configuration, the left and right tensions of the shape memory alloy wire that is stretched over and contracted by the suspension are balanced, and the lens unit can be moved in a straight line, and can be prevented from slipping. .

  In the present invention, a spring member that urges the lens unit in a direction opposite to the driving tension may be attached to the slide guide shaft.

  With the above configuration, since the shape memory alloy wire is always in a tensioned state, when the lens unit is driven by the expansion and contraction of the wire, the wire tension is substantially constant, and the sleeve is used as the slide guide shaft. The lens unit can be driven while maintaining the pressed state, and the optical performance can be stabilized.

  Further, according to the present invention, the length of the sleeve in the sliding direction and the position where the suspension portion is disposed are arranged such that when the lens unit slides while the shape memory alloy wire contracts, the sleeve ends in the sliding direction of the sleeve. Is characterized in that it has a length and an arrangement position so as to be in contact with the same side portion of the slide guide shaft at the same time. With this configuration, since the inner surface of the sleeve abuts in parallel with the slide guide shaft, the occurrence of tilt can be completely prevented. Further, the tilt does not reverse during the reciprocating movement in the optical axis direction.

  According to the present invention, when the driving force is obtained by contracting the shape memory alloy wire, the urging direction of the driving tension is inclined by a predetermined angle from the optical axis, and the sleeve included in the lens unit is pressed against the slide guide shaft. By driving while exerting the pressing force, it is possible to obtain a drive device using a shape memory alloy that has no change in tilt, enables stable linear movement of the lens unit, and has stable optical performance.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an example of an embodiment of a drive device using a shape memory alloy according to the present invention, in which FIG. 2 (a) shows a front view thereof and FIG. 1 (b) shows a side view thereof. FIG. 3 is a schematic diagram for explaining the displacement of the shape memory alloy wire, and FIG. 4 is a schematic diagram for explaining the force acting on the sleeve and the slide guide shaft.

  First, the overall configuration of the drive device 1 using the shape memory alloy according to the present embodiment will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, a driving device 1 using a shape memory alloy has a lens portion including a lens 2 and a holder 3 that holds the lens, and one side portion in a direction perpendicular to the optical axis of the lens portion. The lens unit includes a sleeve 6 to be provided and a rotation restriction guide portion 9 provided on the other side, and is movable in the direction of the optical axis OL.

  Further, the lens unit engages with the slide guide shaft 4 penetrating the sleeve 6 and having the shaft end fixed to the fixed portion and slidably supporting the lens unit in the optical axis direction, and the rotation restricting guide portion 9. And an anti-sway portion 5 that restricts rotation around the optical axis. Further, the driving device obtains a sliding driving force via a shape memory alloy wire 8 installed between the fixed portion and the lens unit.

  As the shape memory alloy wire 8, it is possible to use a single shape memory alloy wire installed between the fixed portion and the lens unit. However, an intermediate portion of the shape memory alloy wire 8 is wound around the lens unit portion. The two ends of the shape memory alloy wire 8 to be folded and fixed to two other fixed terminal portions can be used effectively, and the length of the shape memory alloy wire 8 to be suspended can be reduced. It can be lengthened and is preferable because the amount of displacement can be increased. For this purpose, the lens unit is slid in the optical axis direction via a shape memory alloy wire 8 that is suspended from and suspended from the suspension portion provided outside the sleeve 6. Further, in the present embodiment, as the suspension portion, a projection portion 11 provided so as to protrude outside the sleeve 6 is used.

  Both ends of the shape memory alloy wire 8 are fixed to the fixed terminal portion 10 provided in the fixed portion. In the present embodiment, the shape memory alloy wire 8 contracts at the position where the fixed terminal portion 10 is disposed. The position is displaced in the direction of the rotation restricting guide portion 9 on the other end side from the protruding portion 11 in front of the sliding direction.

  For this purpose, the shape memory alloy wire 8 is installed so as to cross the sleeve 6 and the slide guide shaft 4 obliquely, and the drive tension applied when the shape memory alloy wire 8 contracts. The direction is a direction inclined by a predetermined angle θ1 from the optical axis OL that is the sliding direction, and a force that presses the inner wall of the sleeve 6 against the slide guide shaft 4 acts.

  Further, as shown in FIG. 2A, the rotation restricting guide portion 9 is configured to include a first guide piece 9a and a second guide piece 9b that sandwich the shaft-like steady-state preventing portion 5, and the lens unit includes It is restricted so as not to rotate around the slide guide shaft 4. However, the rotation restricting guide portion 9 may have other shapes, for example, a shape in which a rail-shaped guide member is provided in the fixed portion and an engagement member that engages with the rail-shaped guide member is provided. It is not limited.

  The slide guide shaft 4 and the steadying portion 5 are both disposed in parallel with the optical axis OL, and the lens unit slides along the slide guide shaft 4 and the steadying portion 5 so that the direction of the optical axis OL is achieved. It is set to move straight ahead.

  A clearance is provided between the steady rest 5 and each guide piece 9a, 9b, so that the straight movement of the lens unit is not hindered by the steady rest. Therefore, in order to reduce the shake of the optical axis due to this clearance, the sleeve 6 and the rotation restricting guide portion 9 are provided separately at both ends of the lens unit, and the slide guide shaft 4 and the steady stop portion 5 are provided. The separation distance is increased.

  With this configuration, it is possible to minimize the play and shake caused by the clearance between the slide guide shaft 4 and the sleeve 6 and the clearance between the steady rest 5 and the rotation restricting guide 9. .

  The shape memory alloy wire 8 whose intermediate portion is suspended from the protrusion 11 is fixed at both ends to fixed terminal portions 10 and 10 attached to the fixed portion. Further, the shape memory alloy wire 8 on both sides of the projection 11 serving as a suspension is suspended at an angle θ3 as shown in the figure because it is suspended from the projection 11 along the outer peripheral surface of the sleeve 6 at a predetermined angle. It is arranged in an open V shape.

  Therefore, when the shape memory alloy wire 8 suspended in this state contracts, the sleeve 6 moves straight in parallel with the optical axis OL, and at the same time, a pressing force F1 that urges the sleeve 6 in the direction toward the optical axis OL acts. . That is, the lens unit is moved linearly while pressing the inner surface of the sleeve 6 against the slide guide shaft 4.

  1 and 2B, a spring member 7 (bias spring) is attached to the slide guide shaft 4, and the lens unit is driven when the sleeve 6 is contracted by the shape memory alloy wire 8. The driving force is biased in the opposite direction. With this configuration, the lens unit can be driven in a state where the spring force of the shape memory alloy wire 8 and the spring force of the spring member 7 are balanced and balanced.

  Therefore, when the lens unit is driven by expansion / contraction of the shape memory alloy wire 8, the lens unit is maintained in a state where the wire tension is substantially constant and the sleeve 6 is pressed against the slide guide shaft 4. The optical performance can be stabilized.

  Further, by providing the two fixed terminal portions 10 and 10 at substantially the same distance from the protrusion 11, the right and left tension of the shape memory alloy wire 8 wound around the protrusion 11 and contracted can be reduced. It is balanced to prevent the occurrence of slipping, and the optical performance is stabilized.

  The protrusion 11 that is suspended so that the shape memory alloy wire 8 is wound is preferably made of a hard member having heat resistance and wear resistance and an arcuate suspension. This is because the suspended portion is not easily worn by the shape memory alloy wire 8 that expands and contracts, and the shape memory alloy wire is not easily cut, resulting in a long-life driving device.

  As the spring member 7, for example, a coil spring mounted coaxially with the slide guide shaft 4 can be used. However, the spring member 7 is not limited to a coil spring and may be a spring member other than this, and does not need to be provided coaxially with the slide guide shaft 4. However, using a coil spring arranged coaxially with the slide guide shaft 4 in this manner is preferable because it is not necessary to provide a new space for mounting the spring or a guide member.

  In the present embodiment, a shape memory alloy mainly composed of nickel / titanium is used as the shape memory alloy wire 8. In addition, a high-strength shape memory alloy wire made of nickel / titanium has been developed. For example, there is a wire having a wire diameter of 0.04 mm and a tension of about 13 gf. Considering that the resin lens used in the optical system of the optical pickup is usually less than 0.5 g, an electromagnetic actuator that can exert a sufficient driving force with a single wire and requires a magnet or a coil. Compared to the above, there are few parts, and the material and method are suitable for cost reduction and miniaturization.

  Next, the contraction of the shape memory alloy wire 8 and the displacement of the driven body 11A will be described with reference to the schematic diagram shown in FIG. Consider a case where the shape memory alloy wire 8A bent at an angle θ4 is shortened by being energized from the fixed terminal portions 10A and 10A at both ends and displaced to the shape memory alloy wire 8B indicated by a broken line. At this time, when the length L1 of one side of the shape memory alloy wire is shortened, the driven body 11A located at the bent portion becomes the driven body 11B at the position moved by the distance L2.

  The ratio between the shortened length L1 of the shape memory alloy wire and the movement amount L2 of the driven body is the enlargement factor, and this enlargement factor can be obtained from the angle θ4. For example, when θ4 is 90 °, it is clear that the enlargement ratio is 1.4 times by the trigonometric method. Further, when θ4 is 120 °, it is doubled.

  As described above, when the shape memory alloy wire 8 is hung at the intermediate portion of the driven body 11A and bent in a V shape, the driven portion is driven at a predetermined magnification according to the bending angle. The body 11A can be displaced. At this time, the shape memory alloy wire 8 may be wound around the driven body 11A, or may be fixed to the driven body 11A with an adhesive or the like. Alternatively, the driven body 11A may be provided with a notch and hooked. However, in any case, in order to make contact smoothly as described above, it is preferable to make contact through an arcuate suspension.

  The both ends of the shape memory alloy wire 8 are fixed terminal portions which are formed by bending a thin plate-like material and inserting it between them to press and fix them. A power supply circuit is connected to this terminal portion, energization control for supplying a predetermined driving current is performed, and the shape memory alloy wire 8 is contracted.

  Next, the force acting on the sleeve and the slide guide shaft will be described with reference to FIG. The urging force G from the aforementioned spring member acts on the sleeve 6 in the direction of the arrow in the figure. At this time, when the shape memory alloy wire 8 is contracted and the driving tension F is applied, the component force F2 is applied in the direction in which the sleeve 6 and the holder 3 are pulled up in the direction against the biasing force G, and the sleeve 6 is slid. A pressing force F1 acts as a component force pressed against the guide shaft 4.

  Further, a frictional force Fm is generated between the sleeve 6 and the slide guide shaft 4. Since this frictional force acts in a direction opposite to the direction in which the sleeve 6 moves, that is, in the same direction as the biasing force G by the spring member, the sleeve 6 and the sum of G + Fm and the driving tension F are balanced. The holder 3 moves.

  The frictional force Fm is a numerical value obtained by multiplying the pressing force F1 by the friction coefficient α between the sleeve 6 and the slide guide shaft 4, and the influence of friction can be reduced by reducing the friction coefficient α. . For this purpose, a material in which the sleeve 6 and the slide guide shaft 4 have low friction, for example, a DLC coating member (diamond-like carbon film member) may be used.

  In order to drive the sleeve 6 and the holder 3, that is, the lens unit, against the frictional force and the biasing force G, the angle θ2 formed by the direction perpendicular to the sliding direction and the driving tension F is equal to or greater than a predetermined angle. is necessary. That is, there is a minimum possible angle of the angle θ2. Therefore, there exists a maximum possible angle of an angle θ1 between the optical axis direction that is the sliding direction and the stretching direction of the shape memory alloy wire 8. In addition, a rotational moment acts on the lens unit to be driven depending on the stretching direction of the shape memory alloy wire 8 (the direction in which the driving tension F acts). Since this moment acts on the center of gravity 30 of the lens unit, the drive tension F acts and the sleeve 6 is pressed against the slide guide shaft 4, that is, the tip 61 of the sleeve 6 and the arm length R2 to the center of gravity 30. The ratio between the tip 61 and the arm length R1 to the suspension of the protrusion 11 on which the driving tension F acts is also related.

  That is, the moment force can be defined by the drive tension F, the angle θ1, and the ratio of R1 and R2, and by increasing the angle θ1, the moment force is reduced and the influence of the moment force is reduced. It becomes possible. That is, the limit minimum angle of the angle θ1 can be defined.

  When the ratio of R1 and R2 is 1: 5, the driving tension F is 9.8 mN (1 gf), the lens unit weight is 0.2 g, and the calculation and experiment are performed, the minimum angle of the angle θ1 is 30. It became clear that it was about °. Further, by adjusting parameters such as the ratio of R1 and R2 and the driving tension F, the minimum angle of the angle θ1 can be made slightly smaller, so the limit minimum angle of the angle θ1 is assumed to be about 20 °. The

  Further, the maximum possible angle of the angle θ1 was found to be about 80 ° by calculation and experiment (when the friction coefficient is 0.1). Therefore, the use range of the angle θ1 is assumed to be 20 to 80 °, and preferably 30 ° to 70 °.

  Since the shape memory alloy wire is stretched at a predetermined angle with respect to the optical axis, the inner surface of the sleeve 6 is pressed against the slide guide shaft 4. At this time, it is desirable that the front and rear ends of the sleeve 6 in the sliding direction are simultaneously pressed in parallel. Even if the sliding direction is reversed, it is preferable that the same surface of the sleeve 6 is in contact with the slide guide shaft 4 in the same manner. That is, it is desirable that the front end portion 61 and the rear end portion 62 shown in FIG. 4 are reciprocally driven while maintaining a state in which the front end portion 61 and the rear end portion 62 are always in contact with the slide guide shaft 4.

  For this purpose, the length of the sleeve 6 in the sliding direction and the position of the projection 11 serving as a suspension portion are set according to the sliding direction of the sleeve 6 when the lens unit slides with the shape memory alloy wire 8 contracted. It is important that the front and rear end portions 61 and 62 have such a length and arrangement position that the end portions 61 and 62 are in contact with the same side portion of the slide guide shaft 4 at the same time. With this configuration, since the inner surface of the sleeve always abuts against the slide guide shaft 4 in parallel, it is possible to completely prevent the occurrence or change of tilt. Therefore, the tilt is not reversed during reciprocal movement in the optical axis direction.

  When the direction of stretching the shape memory alloy wire 8 is inclined, it is also possible to incline in a direction away from the optical axis only for moving the lens unit in a straight line. However, in this case, it is necessary to provide an installation space for the shape memory alloy wire 8 outside the area on the side of the lens unit installation space in the direction away from the lens unit, which is not preferable because the apparatus becomes large.

  Further, when the shape memory alloy wire 8 is tilted toward the optical axis direction so as to cross the slide guide shaft diagonally, the shape memory alloy wire 8 interferes with the holder or the lens with a single wire. However, it can be disposed along the outer periphery of the lens portion by bending it into a V shape as in the present embodiment. If it is a wire-shaped shape memory alloy, it can be arranged so as to surround the lens portion, and the installation space can be reduced. Further, by arranging the shape memory alloy wire 8 so as to be inclined, the length can be increased, and even a shape memory alloy that contracts only by a predetermined ratio can increase the contraction length. The moving amount of the driving body can be secured.

  Next, the operation of driving the lens unit by the expansion and contraction of the shape memory alloy wire 8 will be described again. From the non-heated state shown in FIG. 1, electricity is supplied from the fixed terminal portions 10 at both ends, and the shape memory alloy wire 8 is heated and contracted. In the non-heated state, it stops at a position where the tension of the spring member 7 and the shape memory alloy wire 8 is balanced, and in this state, a gap d is formed between the sleeve 6 and the side wall.

  When the shape memory alloy wire 8 is heated and contracted from this state, as described above, the lens unit (holder 3) is maintained while maintaining a state where the tension of the shape memory alloy wire 8 and the biasing force and frictional force of the spring member 7 are balanced. And the sleeve 6) move. That is, the tension is constant and the sleeve 6 is operated while being pressed against the guide shaft 4. When the energization is stopped, the lens unit returns by the urging force of the spring member 7. At this time, the wire tension, the urging force, and the frictional force move in a balanced state. Thus, even when the lens unit is reciprocated in the optical axis direction, the sleeve 6 always operates while being pressed against the guide shaft 4. For this reason, even if there is a clearance between the sleeve 6 and the guide shaft 4, the tilt hardly occurs and the occurrence and change of tilt are suppressed.

  The aforementioned gap d can be set to any desired value and may be zero. That is, the sleeve 6 may be in contact with the side wall when not heated. However, also in this case, it is important to dispose the fixed terminal portion at a position where the shape memory alloy wire 8 does not loosen.

  In addition, the suspension portion needs to be a material having heat resistance and resistance to tension of the shape memory alloy in consideration that the shape memory alloy wire is energized and heated. For example, a metal pin such as stainless steel may be fixed to the sleeve, or the sleeve and the suspension may be formed by integral molding using a resin having high heat resistance such as liquid crystal polymer or PEEK.

  As described above, according to the drive device according to the present invention, the shape memory alloy wire is suspended obliquely with respect to the slide guide shaft, thereby suppressing the tilt and allowing the lens unit to move in a straight line stably. A drive device using a shape memory alloy that stabilizes optical performance can be obtained. Therefore, it can be used as a driving device suitable for an imaging apparatus having a small lens unit that moves the lens in a straight line in the optical axis direction.

These are top views which show an example of embodiment of the drive device using the shape memory alloy which concerns on this invention. 1A shows a front view of FIG. 1, and FIG. 1B shows a side view of FIG. These are the schematic diagrams explaining the displacement of a shape memory alloy wire. These are the schematic diagrams explaining the force which acts on a sleeve and a slide guide shaft.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive device 2 Lens 3 Holder 4 Slide guide shaft 5 Stabilization part 6 Sleeve 7 Spring member 8 Shape memory alloy wire 9 Rotation restriction guide part 10 Fixed terminal part 11 Protrusion part (suspension part)
F Drive tension

Claims (4)

A lens unit including a lens and a lens unit including a holder for holding the lens; a sleeve provided on one side of the lens unit; and a rotation regulation guide provided on the other side; and a shaft end fixed through the sleeve. A slide guide shaft that is fixed to a portion and supports the lens unit so as to be slidable in the optical axis direction, and an anti-sway portion that engages with the rotation restriction guide portion and restricts rotation of the lens unit about the optical axis. A driving device for obtaining a driving force to slide through a shape memory alloy wire laid between the fixed portion and the lens unit,
The shape memory alloy wire is installed between a suspension provided on the outside of the sleeve and a fixed terminal provided on the fixed part,
The fixed terminal portion is provided in front of the slide direction and at a position displaced in the direction of the rotation restricting guide portion on the other end side from the suspension portion, so that the shape memory alloy wire obliquely crosses the slide guide shaft. Provided in
The direction in which the driving tension exerted when the shape memory alloy wire contracts is a direction inclined by a predetermined angle from the optical axis so as to generate a pressing force that presses the sleeve against the slide guide shaft. A drive device using a featured shape memory alloy.   The intermediate part of the shape memory alloy wire is stretched over the suspension part, and both ends of the folded shape memory alloy wire are fixed to two different fixed terminal parts, respectively, and the two fixed terminal parts are The drive device using the shape memory alloy according to claim 1, wherein each of the drive devices is provided at an approximately equal distance from the suspension portion.   The drive device using a shape memory alloy according to claim 1 or 2, wherein a spring member that urges the lens unit in a direction opposite to the drive tension is attached to the slide guide shaft.   The length of the sleeve in the sliding direction and the position where the suspension portion is disposed are such that when the lens unit slides with the shape memory alloy wire contracted, the front and rear ends of the sleeve in the sliding direction are the slide guide shafts. 4. The driving device using a shape memory alloy according to claim 1, wherein the length and the arrangement position are such that the two contact portions are simultaneously brought into contact with the same side portion.

Images