JP2006267178A - Lens driving device and driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator which can be miniaturized. <P>SOLUTION: In the lens driving device, a moving lens is stored in a lens barrel 13, a cam barrel 14 is turnably provided outside the lens barrel 13 and has a cam structure for guiding the moving lens in an axial direction in accordance with the turn inside, a first shape memory alloy wire 16 is wound on the outside of the cam barrel 14 so that it turns in one direction by a change in wire length, and a second shape memory alloy wire 18 is wound on the outside of the cam barrel 14 in a direction opposite to that of the first shape memory alloy wire 16 so as to turn the cam barrel 14 in the direction opposite to the one direction by the change in the wire length. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens driving device provided with a cam.

  Conventionally, a cam type lens driving device is provided in a camera device with a zoom function, for example. This type of lens driving device includes a motor such as a DC motor or a stepping motor as a driving source and a cam to which the rotational force of the motor is transmitted via a speed reduction mechanism, and moves the lens following the cam (for example, Patent Document 1).

  In addition, a lens driving device that includes a spring made of a shape memory alloy arranged along the optical axis of the lens and moves the lens by expansion and contraction of the spring has been proposed (for example, see Patent Document 2).

Patent Document 3 discloses a drive device having a shape memory alloy wire. The drive device of this document includes a shape memory alloy wire formed in a coil shape, and drives a driven object using the shape memory effect. That is, the deformation of the shape memory alloy wire due to heat is converted into the motion of the driven object.
Japanese Patent Laid-Open No. 11-174411 (page 2-3, FIG. 1) JP-A-9-127398 (page 2-3, FIG. 5) JP-A-2-241990 (page 2-3, FIG. 1)

  However, the conventional lens driving device requires a motor and its speed reduction mechanism in order to make the cam function, and it is necessary to secure those spaces, and the mechanism such as the motor is complicated. It was not easy to downsize. Further, the conventional lens driving device including a spring made of a shape memory alloy cannot easily be miniaturized because the coiled shape memory alloy wire takes up space.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a lens driving device that can be miniaturized.

  The lens driving device of the present invention includes a lens barrel that houses a moving lens, and a cam structure that is rotatably provided on the outside of the lens barrel and guides the moving lens in the optical axis direction as the lens rotates. A cam cylinder provided; a first shape memory alloy wire wound around the cam cylinder so as to rotate the cam cylinder in one direction according to a change in line length; and the cam cylinder according to a change in line length. And a second shape memory alloy wire wound around the outer side of the cam cylinder in a direction opposite to the first shape memory alloy wire so as to rotate in a direction opposite to the one direction.

  With this configuration, the shape memory alloy wire is wound around the cam cylinder, the cam cylinder is rotated by the change of the line length, and the lens can be moved by the rotation of the cam cylinder. By winding the shape memory alloy wire around the cam cylinder, the wire length can be increased. As a result, even if the distortion rate of the shape memory alloy wire is small, the amount of change in the wire length can be increased, and the lens can be moved appropriately. Further, the first and second shape memory alloy wires wound in opposite directions can rotate the cam cylinder in both directions, and the movable lens can be moved in both directions. Thus, according to the present invention, since the lens can be moved with a simple and space-saving configuration in which a cam cylinder is placed outside the lens barrel and a wire rod is wound around the cam cylinder, the lens driving device can be downsized. It is.

  Preferably, the shape memory alloy wire is wound around the cam cylinder a plurality of times, whereby the wire length can be increased. Further, the shape memory alloy wire is preferably wound around the cam cylinder in a spiral manner, and the wire length can be suitably increased.

  In the lens driving device of the present invention, a slide terminal is provided at an end of the first shape memory alloy wire and the second shape memory alloy wire, and a fixed terminal is provided so that the slide terminal slides. A spring is provided between the slide terminal and the fixed terminal so as to be deformable in the length direction of the first shape memory alloy wire or the second shape memory alloy wire.

  With this configuration, when one of the first shape memory alloy wire and the second shape memory alloy wire contracts, the slide terminal slides against the fixed terminal at the end of the alloy wire and the spring contracts, Cutting of the alloy wire can be prevented by the buffering effect of the spring.

  In the lens driving device of the present invention, the first and second shape memory alloy wires are respectively wound around first and second spiral grooves provided outside the cam cylinder, The first and second spiral grooves have different depths and are provided in opposite directions.

  With this configuration, since the shape memory alloy wire is wound spirally, the wire length can be increased. Further, since the shape memory alloy wire is accommodated in the spiral groove, further miniaturization can be achieved. Furthermore, by making the depths of the first and second spiral grooves different, contact between the first and second shape memory alloy wires can be avoided, and one alloy wire is affected by the heat of the other alloy wire. Can be avoided, and the influence of friction between both alloy wires can be avoided.

  Moreover, a U-turn part may be provided in the spiral groove to form a U-turn. With this configuration, since the shape memory alloy wire is U-turned, both ends of the shape memory alloy wire can be positioned close to each other, the configuration for connecting the power source to the shape memory alloy wire can be simplified, and the apparatus can be simplified. As a result, the size can be reduced.

  In the lens driving device of the present invention, the moving lens is held by a lens holding frame, a guide pin protrudes from the lens holding frame, and the lens barrel is provided to extend in the optical axis direction. The guide pin has an elongated hole through which the cam cylinder cam structure has a cam groove into which the guide pin is inserted.

  With this configuration, as the cam barrel rotates, the moving lens can be moved linearly along the elongated hole of the barrel and according to the setting of the cam groove, and the moving lens can be suitably moved. Can do.

  Further, the lens driving device of the present invention is connected to the lens driving circuit for supplying current to the first and second shape memory alloy wires, a controller for sending a control signal to the lens driving circuit, the controller, And a variable resistor that changes a control signal sent from the controller to the lens driving circuit to change a current supplied from the lens driving circuit to the first and second shape memory alloys.

  With this configuration, the position of the lens can be controlled with a simple control configuration in which a variable resistor is connected to the controller, and the device can be simplified and thereby downsized.

  In the lens driving device of the present invention, the lens driving circuit performs PWM energization to the first and second shape memory alloy wires, and the variable resistor performs PWM energization pulses according to a change in resistance value. Change the interval.

  With this configuration, the lens can be moved to a desired position by changing the resistance value of the variable resistor.

  The camera device of the present invention includes the lens driving device described above. With this configuration, the advantages of the present invention can be obtained in the camera device, and the camera device can be downsized.

  Further, another aspect of the present invention is a driving device, and the driving device is provided with a rotating body having a driving mechanism that moves a driven object with rotation, and the rotating body is moved in one direction by changing a line length. The first shape memory alloy wire wound around the rotating body so as to be rotated, and the rotating body is rotated in the direction opposite to the one direction by changing the wire length. A second shape memory alloy wire wound in the opposite direction to the first shape memory alloy wire. In this configuration, the driven object is not limited to a lens. With this configuration, similarly to the above-described invention, the driven object can be moved with a simple and space-saving configuration in which a wire rod is wound around a rotating body, so that the size of the driving device can be reduced.

  In the driving device of the present invention, the first and second shape memory alloy wires are respectively wound around first and second spiral grooves provided outside the rotating body, The first and second spiral grooves have different depths and are provided in opposite directions.

  With this configuration, since the shape memory alloy wire is wound spirally, the wire length can be increased. Further, since the shape memory alloy wire is accommodated in the spiral groove, further miniaturization can be achieved. Furthermore, by making the depths of the first and second spiral grooves different, contact between the first and second shape memory alloy wires can be avoided, and the influence of both heat and friction can be avoided.

  In the drive device of the present invention, the rotating body is a cam cylinder provided with a cam structure as the drive mechanism inside. With this configuration, the driven object can be driven by the cam structure.

  Another aspect of the present invention is a driving device, which includes a first shape memory alloy wire provided to move a driven object in one direction by a change in line length, and a wire length A second shape memory alloy wire provided in a direction opposite to the first shape memory alloy wire so as to move the driven object in a direction opposite to the one direction by the change, A slide terminal is provided at an end of the shape memory alloy wire and the second shape memory alloy wire, a fixed terminal is provided so that the slide terminal slides, and the first terminal is provided between the slide terminal and the fixed terminal. A spring is provided so as to be deformable in the length direction of the first shape memory alloy wire or the second shape memory alloy wire. Even in this configuration, the driven object is not limited to the lens. In this configuration, the shape memory alloy wire may not be wound. With this configuration, when one alloy wire of the first shape memory alloy wire and the second shape memory alloy wire contracts, the slide terminal slides relative to the fixed terminal at the end of the alloy wire, and the spring A compact drive device using a shape memory alloy wire can be provided while contracting and avoiding cutting of the alloy wire.

  The present invention has an effect that a lens can be moved with a simple configuration by providing a cam cylinder outside the lens barrel and winding a shape memory alloy wire around the cam cylinder, which can be simplified and miniaturized. A lens driving device can be provided.

  Hereinafter, a lens driving device according to an embodiment of the present invention will be described with reference to the drawings.

  1 and 2 are perspective views of a lens driving device according to an embodiment of the present invention, and FIG. 3 is a front view.

  1 to 3, the lens driving device 10 includes a lens barrel 13 that houses a first moving lens 11 and a second moving lens (not shown), and a cam tube 14 that is rotatably provided outside the lens barrel 13. I have. The cam cylinder 14 includes a cam structure that guides the moving lens in the optical axis direction as it rotates.

  The first shape memory alloy wire 16 and the second shape memory alloy wire 18 are wound around the outer side of the cam cylinder 14 in a spiral manner so that the cam cylinder 14 is rotated by changing the line length. The first shape memory alloy wire 16 and the second shape memory alloy wire 18 are wound in opposite directions. In the present embodiment, when the camera is viewed from the front, the first shape memory alloy wire 16 is wound in the right screw direction, and the second shape memory alloy wire 18 is wound in the left screw direction. The first shape memory alloy wire 16 and the second shape memory alloy wire 18 are U-turned near the tip of the cam barrel 14, and both ends are attached near the root of the lens barrel 13.

  In the present embodiment, the first shape memory alloy wire 16 and the second shape memory alloy wire 18 are wound along the first spiral groove 20 and the second spiral groove 22 on the outer periphery of the cam cylinder 14, respectively. The first spiral groove 20 and the second spiral groove 22 are provided in opposite directions, that is, the former is provided in the right-handed screw direction and the latter is provided in the left-handed screw direction.

  The first spiral groove 20 is a double spiral groove. The first spiral groove 20 starts from the vicinity of the root of the cam cylinder 14 and travels toward the tip while making approximately two rounds of the cam cylinder 14. The first spiral groove 20 makes a U-turn near the tip and returns to the root of the cam cylinder 14. A protrusion 24 is provided on the U-turn portion of the first spiral groove 20, and the central portion of the first shape memory alloy wire 16 is hooked on the protrusion 24. Then, both ends of the first shape memory alloy wire 16 are attached to the printed circuit board 28. The printed circuit board 28 is fixed to the base portion (in the figure, a rectangular parallelepiped) of the lens barrel 13.

  Similarly to the first spiral groove 20, the second spiral groove 22 is also a double spiral groove although the direction is opposite. Then, the second spiral groove 22 starts from the starting point on the opposite side of the first spiral groove 20 near the root of the cam cylinder 14 and heads toward the tip while making approximately two rounds of the cam cylinder 14. The second spiral groove 22 makes a U-turn near the tip and returns to the root of the cam cylinder 14. A protrusion 26 is provided on the U-turn portion of the second spiral groove 22, and the central portion of the second shape memory alloy wire 18 is hooked on the protrusion 26. The protrusion 26 is provided on the side opposite to the protrusion 24 of the first spiral groove 20. Also, both ends of the second shape memory alloy wire 18 are attached to the printed circuit board 28 in the same manner as the first shape memory alloy wire 16. However, the end of the second shape memory alloy wire 18 is positioned opposite to the end of the first shape memory alloy wire 16 with the lens barrel 13 in between.

  The first shape memory alloy wire 16 and the second shape memory alloy wire 18 are buried in the first spiral groove 20 and the second spiral groove 22, respectively, and do not protrude from the outer peripheral surface of the cam cylinder 14. The first shape memory alloy wire 16 and the second shape memory alloy wire 18 are located at the bottoms of the first spiral groove 20 and the second spiral groove 22.

  Further, the first spiral groove 20 and the second spiral groove 22 have different depths. In the present embodiment, the second spiral groove 22 is deeper than the first spiral groove 20. The difference in depth between the first spiral groove 20 and the second spiral groove 22 is set larger than the diameter of the alloy wire. As a result, the first shape memory alloy wire 16 and the second shape memory alloy wire 18 intersect without contacting each other.

  The first shape memory alloy wire 16 and the second shape memory alloy wire 18 are wires made of a shape memory alloy. Shape memory alloys that have undergone memory heat treatment have the property of returning to their original shape when stored at high temperatures, even if they are deformed at low temperatures. In the present embodiment, the first shape memory alloy wire 16 and the second shape memory alloy wire 18 contract by heating. When the first shape memory alloy wire 16 contracts, the cam cylinder 14 rotates clockwise with respect to the lens barrel 13 when viewed from the front. On the other hand, when the second shape memory alloy wire 18 contracts, the cam cylinder 14 rotates counterclockwise with respect to the lens barrel 13 when viewed from the front. In the present embodiment, one alloy wire is heated at a time, and the heated alloy wire contracts to rotate the cam cylinder 14.

  However, the shape memory alloy has a small kinematic strain of about 1% in the bending direction, torsional direction, and length direction that can be used repeatedly. Therefore, in the present embodiment, the wire length is increased by winding the shape memory alloy wire in a spiral shape. As a result, the line length change amount is increased, and the amount of rotation of the cam cylinder 14 is also increased.

  In the present embodiment, a linear shape memory alloy wire is wound around the cam cylinder 14. However, the present invention is not limited to this, and for example, a shape memory alloy wire formed into a coil shape may be wound around the cam cylinder.

  Next, the attachment structure of the terminal portions of the first shape memory alloy wire 16 and the second shape memory alloy wire 18 will be described. The end portion of the shape memory alloy wire is a contact portion for supplying current, and is attached to the printed circuit board 28 fixed to the lens barrel 13 as described above.

  FIG. 4 is a cross-sectional view of the contact portion of the first shape memory alloy wire 16, and FIG. 5 is an exploded view of the contact portion of the first shape memory alloy wire 16 and the second shape memory alloy wire 18. The contact portion of the second shape memory alloy wire 18 also has the same configuration as that in FIG.

  In FIG. 4, columnar slide terminals 30a and 30b are fixed to the end of the first shape memory alloy wire 16 by caulking. On the other hand, cylindrical fixed terminals 32 a and 32 b are fixed to the printed circuit board 28. Then, the slide terminals 30a and 30b are fitted into the fixed terminals 32a and 32b, and the slide terminals 30a and 30b slide with the fixed terminals 32a and 32b.

  Springs 34a and 34b are provided between the slide terminals 30a and 30b and the fixed terminals 32a and 32b. One ends of the springs 34a and 34b are in contact with the flanges of the slide terminals 30a and 30b, and the other ends are in contact with the end surfaces of the fixed terminals 32a and 32b. The springs 34a and 34b are provided in a compressed state, whereby the springs 34a and 34b are moved in the direction in which the slide terminals 30a and 30b are separated from the lens barrel 13, that is, the first shape memory alloy wire 16 is The slide terminals 30a and 30b are biased in the direction in which they are pulled. The sag of the first shape memory alloy wire 16 is also prevented by the urging force of the springs 34a and 34b.

  The contact portion of the second shape memory alloy wire 18 has the same configuration. Briefly described in order to avoid duplication, the slide terminals 30c and 30d are fixed to the end of the second shape memory alloy wire 18 by caulking, and the fixed terminals 32c and 32d are fixed to the printed circuit board 28. . The slide terminals 30c and 30d are fitted to the fixed terminals 32c and 32d, and the slide terminals 30c and 30d slide with the fixed terminals 32c and 32d. Further, springs 34c and 34d are provided between the slide terminals 30c and 30d and the fixed terminals 32c and 32d. The springs 34c and 34d are provided in a compressed state, and bias the slide terminals 30c and 30d in a direction in which the second shape memory alloy wire 18 is pulled.

  On the printed circuit board 28, individual patterns 36a and 36c and a common pattern 38 are provided. On the first shape memory alloy wire 16 side, the fixed terminal 32 a is fixed on the individual pattern 36 a and the fixed terminal 32 b is fixed on the common pattern 38. Thereby, both ends of the first shape memory alloy wire 16 are electrically connected to the individual pattern 36a and the common pattern 38 via the slide terminals 30a and 30b and the fixed terminals 32a and 32b (conductive coupling).

  On the second shape memory alloy wire 18 side, the fixed terminal 32 c is fixed on the individual pattern 36 c, and the fixed terminal 32 d is fixed on the common pattern 38. Thus, both ends of the second shape memory alloy wire 18 are electrically connected to the individual pattern 36c and the common pattern 38 via the slide terminals 30c and 30d and the fixed terminals 32c and 32d (conducting coupling).

  The ends of the individual patterns 36a and 36c and the common pattern 38 are terminals, and are connected to a power source via a board connector. A current is supplied to the first shape memory alloy wire 16 using the individual pattern 36a and the common pattern 38, and a current is supplied to the second shape memory alloy wire 18 using the individual pattern 36c and the common pattern 38. . Here, the common pattern 38 functions as a common terminal for supplying current to both alloy wires.

  6 is a perspective view of the camera driving device 10 with the cam barrel 14 removed, FIG. 7 shows the inside of the cam barrel 14, and FIG. 8 is an exploded view of the camera driving device 10. With reference to these drawings, a detailed configuration of each part of the camera driving device 10 will be described.

  In FIG. 6, the lens barrel 13 is indicated by an imaginary line so that the internal configuration can be seen. The lens barrel 13 includes a base portion 40 and a cylindrical portion 42 that protrudes forward from the base portion 40.

  The base unit 40 accommodates an imaging unit 44 and a fixed lens 46. The imaging unit 44 includes an imaging element such as a CCD, is fixed to the base unit 40, and a fixed lens 46 is fixed to the front side of the imaging unit 44.

  As described above, the first moving lens 11 and the second moving lens 12 are accommodated in the cylindrical portion 42 of the lens barrel 13. The first moving lens 11 is located on the front side, and the second moving lens 12 is located on the rear side. Both lenses are slidable in the optical axis direction as described below.

  That is, the first moving lens 11 is held by the first lens holding frame 52. The first lens holding frame 52 has an annular shape, and the first moving lens 11 is fixed inside the annular ring. The outer diameter of the first lens holding frame 52 is substantially equal to the inner diameter of the cylindrical portion 42 of the lens barrel 13, and the first lens holding frame 52 is slidably inserted into the cylindrical portion 42.

  A guide pin 54 protrudes from the first lens holding frame 52. Although not shown, there are two guide pins 54, and the other guide pin 54 is provided on the opposite side by 180 degrees. The guide pin 54 passes through a long hole 56 provided in the optical axis direction in the front half of the cylindrical portion 42, and can slide along the long hole 56. With such a configuration, the first moving lens 11 can slide along the first lens holding frame 52 in the optical axis direction without rotating at the front half of the cylindrical portion 42.

  The second moving lens 12 is also held by the lens barrel 13 with the same configuration. That is, the second moving lens 12 is held inside the annular second lens holding frame 58, and the second lens holding frame 58 has an outer diameter that is substantially equal to the inner diameter of the cylindrical portion 42 of the barrel 13. And is inserted into the cylindrical portion 42. Two guide pins 60 protrude from the second lens holding frame 58 at a position 180 degrees apart, and the guide pins 60 are provided in the optical axis direction at the rear half of the cylindrical portion 42. It penetrates the hole 62 and can slide along the long hole 62. With such a configuration, the second moving lens 12 can slide in the optical axis direction without rotating at the rear half of the cylindrical portion 42 together with the second lens holding frame 58.

  In addition, circumferential grooves 64 and 66 for attaching the cam cylinder 14 are provided in the vicinity of the tip and the base of the cylindrical portion 42 of the lens barrel 13.

  Next, as shown in FIG. 7, the cam cylinder 14 has a divided structure, and includes an upper cam 70 and a lower cam 72. The upper cam 70 and the lower cam 72 are semi-cylindrical, and the cylindrical cam cylinder 14 is formed by combining them. The inner diameter of the cam barrel 14 is set substantially equal to the outer diameter of the cylindrical portion 42 of the lens barrel 13.

  As shown in the figure, a first cam groove 78 and a second cam groove 80 are provided on the inner peripheral surface 74 of the upper cam 70 and the inner peripheral surface 76 of the lower cam 72. The first cam groove 78 is provided in the front half, and the second cam groove 80 is provided in the rear half. When the upper cam 70 and the lower cam 72 are mounted around the lens barrel 13 and the cam barrel 14 is formed, the guide pin 54 of the first lens holding frame 52 is slidably inserted into the first cam groove 78, The guide pin 60 of the two-lens holding frame 58 is slidably inserted into the second cam groove 80.

  The first cam groove 78 is provided obliquely with respect to the optical axis at the front half of the upper cam 70 and the lower cam 72 in the same range as the long hole 56 of the lens barrel 13 in the optical axis direction. Yes. The first cam groove 78 causes the first lens holding frame 52 to move rearward (the base side of the cylindrical portion 42 of the lens barrel 13) together with the first moving lens 11 when the cam cylinder 14 rotates clockwise. It is provided to move forward when it rotates clockwise.

  Further, the second cam groove 80 is provided at an angle with respect to the optical axis in the same range as the long hole 62 of the lens barrel 13 in the optical axis direction in the rear half of the upper cam 70 and the lower cam 72. Yes. The second cam groove 80 moves so that the second lens holding frame 58 moves forward together with the second moving lens 12 when the cam cylinder 14 rotates clockwise, and moves backward when the cam cylinder 14 rotates counterclockwise. Is provided.

  Next, referring to FIG. 8, the upper cam 70 and the lower cam 72 are mounted on the outer peripheral surface of the barrel 13 from above and below, and are coupled to each other by bonding or the like, whereby the cam barrel 14 is formed. A first stopper 82 and a second stopper 84 (retaining ring) formed of a metal wire are fitted into the circumferential grooves 64 and 66 of the lens barrel 13. The first clasp 82 and the second clasp 84 are positioned on both sides of the cam cylinder 14, and the cam cylinder 14 is rotatably mounted on the lens barrel 13 without moving in the optical axis direction.

  Further, grooves are provided on the outer peripheral surfaces of the upper cam 70 and the lower cam 72. When the upper cam 70 and the lower cam 72 are combined, the groove is continuous, and as described above, two double spiral grooves in opposite directions are formed. Then, as already described with reference to FIG. 1, the heat-treated first shape memory alloy wire 16 is hung on the protrusion 24, wound along the spiral groove, and both ends are printed using the slide terminals 30a and 30b. 28 is attached. Similarly, the second shape memory alloy wire 18 is hung on the protrusion 26, wound along the spiral groove, and both ends thereof are attached to the printed circuit board 28 using the slide terminals 30c and 30d.

  Next, FIG. 9 shows a camera device 92 provided with the lens driving device 10 of the present embodiment. The camera device 92 includes a housing 94 indicated by an imaginary line, and the lens driving device 10 is accommodated in the housing 94. Although not shown, the camera device 92 includes configurations such as an image sensor, an image processing circuit, a power supply circuit, and a pan / tilt mechanism in addition to the lens driving device 10. The camera device 92 is, for example, a monitoring camera or a monitoring camera. The monitoring camera can be used to provide a video of a remote place via a network such as the Internet.

  FIG. 10 shows a control device of the lens driving device 10. The control device 100 includes a lens driving circuit 102, a controller 104, a variable resistor 106, and a switch 108 as switching means. The lens driving circuit 102 is connected to both ends of the first shape memory alloy wire 16 and both ends of the second shape memory alloy wire 18. However, one end of the first shape memory alloy wire 16 and one end of the second shape memory alloy wire 18 are connected to the lens driving circuit 102 via the switch 108. The switch 108 is controlled by the controller 104. By providing the switch 108, one of the first shape memory alloy wire 16 and the second shape memory alloy wire 18 is connected to the lens driving circuit 102 at a time. The controller 104 controls the switch 108 according to the lens position. The lens position is detected based on a signal from a sensor (not shown), for example.

  In detail, as shown in FIG. 5 described above, the lens driving circuit 102 is further connected to the fixed terminals 32a to 32d and the slide terminals via the individual patterns 36a and 36c and the common pattern 38 on the printed circuit board 28. It is connected to the first shape memory alloy wire 16 and the second shape memory alloy wire 18 through 30a to 30d. The switch 108 is connected to the individual patterns 36a and 36c.

  The lens driving circuit 102 is connected to the controller 104. The controller 104 generates a PWM control signal and outputs it to the lens driving circuit 102. The lens drive circuit 102 applies PWM to the first shape memory alloy wire 16 or the second shape memory alloy wire 18 (the shape memory alloy wire connected by the switch 108) in accordance with the PWM control signal supplied from the controller 104. Energize. The first shape memory alloy wire 16 or the second shape memory alloy wire 18 generates Joule heat by PWM energization and is contracted by being heated by the Joule heat, whereby the cam cylinder 14 is rotated.

  The variable resistor 106 is externally attached to the controller 104. When the resistance value of the variable resistor 106 changes, the PWM control signal changes, and the current supplied from the lens driving circuit 106 to the shape memory alloy wire 16 changes.

  FIG. 11 shows a pulse output from the lens driving circuit 102, and the function of the variable resistor 106 will be described with reference to FIG.

  In FIG. 11, the pulse width c is set and fixed by a volume built in the controller 104. When the resistance value of the variable resistor 106 is changed, the pulse interval d changes. Thereby, the energization time to the shape memory alloy wire is changed, and the supplied power is changed. As the resistance value increases, the pulse interval increases and the power supply decreases. Decreasing the resistance value shortens the pulse interval and increases the power supply.

  FIG. 12 shows the relationship between the resistance value of the variable resistor 106, the pulse interval, the power supplied to the shape memory alloy wire, and the displacement (rotation angle) of the cam barrel. As shown in the figure, when the resistance value is decreased, the pulse interval is decreased and the supply power is increased. As the power supply increases, the temperature of the shape memory alloy wire increases, the amount of contraction of the shape memory alloy wire increases, and the amount of rotation of the cam cylinder also increases.

  In the example of FIG. 12, the cam cylinder is displaced according to the supplied power between the powers a and b. When power b is supplied, the shape memory alloy wire shrinks to the memorized length and does not shrink any further. Therefore, the variable range of the resistance value of the variable resistor 106 is set so that the power changes between a and b.

  Although not shown, the variable resistor 106 is connected to the zoom button and the wide button via a circuit. While the button is pressed, the resistance value continuously changes within the variable range, and when the finger is released from the button, the change in resistance value stops. When the lens position is closer to the zoom side than the standard state described later, the variable resistor 106 or the like has a smaller resistance value when the zoom button is pressed and increases when the wide button is pressed. It is configured as follows. Further, when the lens position is on the wide side from the standard state, the variable resistor 106 or the like has a smaller resistance value when the wide button is pressed and increases when the zoom button is pressed. It is configured as follows. In order to realize such switching, a switch or the like that switches according to the lens position may be provided in the circuit. Further, the variable resistor 106 may be controlled by the controller.

  Next, the operation of the lens driving device 10 described above will be described. First, FIG. 1, FIG. 2, FIG. 3 and FIG. 6, which have already been described, show the lens driving device 10 when the distance between the first moving lens 11 and the second moving lens 12 is standard. This state is the standard state of the lens driving device 10.

  In the standard state, the resistance value of the variable resistor 106 is sufficiently large, or the switch 108 is not connected to either shape memory alloy wire. Therefore, PWM energization is not performed, and the first shape memory alloy wire 16 and the second shape memory alloy wire 18 are at normal temperature (in this embodiment, the normal temperature range is appropriately set). The first moving lens 11 and the second moving lens 12 are located in the middle of the movable range, and the distance between the two lenses is a standard value between the maximum value and the minimum value.

  The operation when the first shape memory alloy wire 16 is energized from the above-described standard state will be described. When the zoom button is operated by the user from the standard state, the switch 108 is switched so that the lens driving circuit 102 is connected to the first shape memory alloy wire 16. Then, the resistance value of the variable resistor 106 decreases, the controller 104 sends a PWM control signal to the lens driving circuit 102, and the lens driving circuit 102 performs PWM energization to the first shape memory alloy wire 16.

  The first shape memory alloy wire 16 is supplied with electric current, generates Joule heat, and is heated by this, and the temperature rises and contracts. As the first shape memory alloy wire 16 becomes shorter, the cam cylinder 14 rotates clockwise. When the cam barrel 14 rotates clockwise, the two guide pins 54 of the first lens holding frame 52 move in the first cam groove 78 and retreat in the elongated hole 56 of the lens barrel 13. Further, the two guide pins 60 of the second lens holding frame 58 move in the second cam groove 80 and advance in the elongated hole 62 of the lens barrel 13. As a result, the first moving lens 11 moves backward, the second moving lens 12 moves forward, and the distance between the two lenses decreases.

  In the above process, the second shape memory alloy wire 18 is not heated and the length is not changed. Therefore, when the cam cylinder 14 rotates clockwise, the second shape memory alloy wire 18 is pulled. In the second shape memory alloy wire 18, the slide terminals 30c and 30d at both ends slide relative to the fixed terminals 32c and 32d, and the springs 34c and 34d contract. Thereby, the shrinkage | contraction part of the 1st shape memory alloy wire 16 is absorbed, and the cutting | disconnection of the 2nd shape memory alloy wire 18 is prevented.

  When the springs 34c and 34d contract at the end of the second shape memory alloy wire 18, the springs 34a and 34b at the end of the first shape memory alloy wire 16 contract by the same amount. Thereby, the rotation amount of the cam cylinder 14 with respect to the contraction of the first shape memory alloy wire 16 is corrected. The rotation amount of the cam cylinder 14 is an amount corresponding to half of the contraction amount of the first shape memory alloy wire 16.

  FIGS. 13, 14 and 15 show a state when the distance between the first moving lens 11 and the second moving lens 12 is reduced. 13 is a perspective view, FIG. 14 is a front view, and FIG. 15 is a perspective view with the cam cylinder 14 removed.

  In FIGS. 13 to 15, as a result of the zoom button being continuously pressed, the cam cylinder 14 is rotated about 60 degrees clockwise from the standard state. The two guide pins 54 of the first lens holding frame 52 come into contact with the rear end (end of the backward direction) of the first cam groove 78, and the two guide pins 60 of the second lens holding frame 58 are in the second cam groove 80. It hits the front end (end in the forward direction). Thus, the first moving lens 11 is located at the rear end of the movable range, the moving lens 12 is located at the front end of the movable range, and the first moving lens 11 and the second moving lens 12 are closest. At this time, the lens driving device 10 is in a telephoto state.

  When the guide pin hits the cam groove end, the rotation of the cam cylinder 14 is restricted even though the first shape memory alloy wire 16 is contracted. Therefore, an impact force acts on the end portion of the first shape memory alloy wire 16. This impact force is alleviated by the buffering effect of the springs 34a and 34b. This buffering effect prevents the shape memory alloy wire from being cut. In addition, the springs 34a to 34d can absorb the impact force applied to the end portion of the alloy wire at the time of starting and stopping the rotation in other cases by contracting.

  When the wide button is pressed in the state of FIG. 13 to FIG. 15, it operates in the direction opposite to the above operation. The resistance value of the variable resistor 106 increases, the supplied power decreases, and the temperature of the first shape memory alloy wire 16 decreases. The first shape memory alloy wire 16 extends, and the cam cylinder 14 rotates counterclockwise. The first moving lens 11 moves forward, the second moving lens 12 moves backward, the distance between them increases, and the lens position approaches the standard state. If the wide button is kept pressed, the lens driving device 10 returns to the standard state.

  Next, the operation when the second shape memory alloy wire 18 is energized from the standard state will be described. When the wide button is operated by the user from the standard state, the switch 108 is switched so that the lens driving circuit 102 is connected to the second shape memory alloy wire 18. Then, the resistance value of the variable resistor 106 decreases, the controller 104 sends a PWM control signal to the lens driving circuit 102, and the lens driving circuit 102 performs PWM energization to the second shape memory alloy wire 18.

  The second shape memory alloy wire 18 is supplied with electric current, generates Joule heat, and is heated by this, so that the temperature rises and contracts. As the second shape memory alloy wire 18 becomes shorter, the cam cylinder 14 rotates counterclockwise. When the cam barrel 14 rotates counterclockwise, the two guide pins 54 of the first lens holding frame 52 move in the first cam groove 78 and advance in the elongated hole 56 of the lens barrel 13. Further, the two guide pins 60 of the second lens holding frame 58 move in the second cam groove 80 and retreat in the elongated hole 62 of the lens barrel 13. As a result, the first moving lens 11 moves forward, the second moving lens 12 moves backward, and the distance between both lenses increases.

  In the above process, the first shape memory alloy wire 16 is not heated and the length is not changed. Therefore, when the cam cylinder 14 rotates clockwise, the first shape memory alloy wire 16 is pulled. In the first shape memory alloy wire 16, the slide terminals 30a and 30b at both ends slide relative to the fixed terminals 32a and 32b, and the springs 34a and 34b contract. Thereby, the shrinkage | contraction part of the 2nd shape memory alloy wire 18 is absorbed, and the cutting | disconnection of the 1st shape memory alloy wire 16 is prevented.

  When the springs 34a and 34b contract at the end of the first shape memory alloy wire 16, the springs 34c and 34d at the end of the second shape memory alloy wire 18 contract by the same amount. Thereby, the rotation amount of the cam cylinder 14 with respect to the contraction of the second shape memory alloy wire 18 is corrected. The rotation amount of the cam cylinder 14 is an amount corresponding to half of the contraction amount of the second shape memory alloy wire 18.

  FIGS. 16, 17 and 18 show a state when the distance between the first moving lens 11 and the second moving lens 12 is increased. 16 is a perspective view, FIG. 17 is a front view, and FIG. 18 is a perspective view with the cam cylinder 14 removed.

  16 to 18, as a result of the wide button being continuously pressed, the cam cylinder 14 is rotated about 60 degrees counterclockwise from the standard state. The two guide pins 54 of the first lens holding frame 52 abut on the front end (end in the forward direction) of the first cam groove 78, and the two guide pins 60 of the second lens holding frame 58 are behind the second cam groove 80. It hits the end (end in the backward direction). Thus, the first moving lens 11 is located at the front end of the movable range, the moving lens 12 is located at the rear end of the movable range, and the first moving lens 11 and the second moving lens 12 are farthest apart. At this time, the lens driving device 10 is in a wide-angle shooting state.

  Again, when the guide pin hits the cam groove end, the rotation of the cam cylinder 14 is restricted, and an impact force acts on the end of the second shape memory alloy wire 18. This impact force is alleviated by the buffer effect of the springs 34b and 34c. This buffering effect prevents the shape memory alloy wire from being cut. In addition, the springs 34a to 34d can absorb the impact force applied to the end portion of the alloy wire at the time of starting and stopping the rotation in other cases by contracting.

  When the zoom button is pressed in the state of FIGS. 16 to 18, it operates in the direction opposite to the above operation. The resistance value of the variable resistor 106 increases, the supplied power decreases, and the temperature of the second shape memory alloy wire 18 decreases. The second shape memory alloy wire 18 extends, and the cam cylinder 14 rotates in the clockwise direction. The first moving lens 11 moves backward, the second moving lens 12 moves forward, the distance between them decreases, and the lens position approaches the standard state. If the zoom button is kept pressed, the lens driving device 10 returns to the standard state.

  As shown in the above description of the operation, the user can bring the lens arrangement closer to the telephoto shooting state by depressing the zoom button. When the zoom button is kept pressed, the lens arrangement reaches the telephoto shooting state. The user can push the wide button down to bring the lens arrangement closer to the wide-angle shooting state. If the user keeps pressing the wide button, the lens arrangement reaches the wide-angle shooting state. Further, the user can operate the button while looking at the viewfinder or the liquid crystal screen, and release the button when the desired shooting range between wide-angle shooting and telephoto shooting is obtained, and can stop the lens. In this manner, the lens driving device 10 can control the lens position so that the lens is positioned not only at the wide-angle end and the telephoto end but also at any intermediate position.

  As described above, according to the lens driving device 10 of the embodiment of the present invention, the lens barrel 13 is covered with the cam cylinder 14 and the shape memory alloy wire is wound around the cam cylinder 14, and the change in the line length is caused. The cam cylinder 14 is rotated, and the lens can be moved by the rotation of the cam cylinder 14. By winding the shape memory alloy wire around the cam cylinder 14, the wire length can be increased. As a result, even if the distortion rate of the shape memory alloy wire is small, the amount of change in the wire length can be increased, and the lens can be moved appropriately. Further, the first and second shape memory alloy wires wound in opposite directions can rotate the cam cylinder in both directions, and the movable lens can be moved in both directions. In this way, the lens can be moved with a simple and space-saving configuration in which the cam barrel is covered outside the lens barrel and the wire rod is wound around the cam barrel, so that the lens driving device can be reduced in size. Preferably, as in the above-described embodiment, the shape memory alloy wire is wound around the cam tube 14 a plurality of times, thereby increasing the wire length. Furthermore, the shape memory alloy wire is preferably wound around the cam cylinder 14 in a spiral manner, and the wire length can be suitably increased.

  Further, according to the present embodiment, the slide terminals are provided at the ends of the first shape memory alloy wire 16 and the second shape memory alloy wire 18, the fixed terminals are provided so that the slide terminals slide, and the slide A spring is provided between the terminal and the fixed terminal so as to be deformable in the length direction of the alloy wire. Thus, when the first shape memory alloy wire 16 or the second shape memory alloy wire 18 contracts, the slide terminal slides against the fixed terminal at the end of the alloy wire and the spring contracts, as described above. In addition, the alloy wire can be prevented from being cut by the buffering effect of the spring.

  Further, according to the present embodiment, the first shape memory alloy wire 16 and the second shape memory alloy wire 18 are respectively wound around the first and second spiral grooves provided on the outer side of the cam cylinder. The first and second spiral grooves have different depths and are provided in opposite directions. Thereby, since the shape memory alloy wire is wound spirally, the wire length can be increased. Further, since the shape memory alloy wire is accommodated in the spiral groove, further miniaturization can be achieved. Furthermore, by making the depths of the first and second spiral grooves different, contact between the first and second shape memory alloy wires can be avoided, and one alloy wire is affected by the heat of the other alloy wire. Can be avoided, and the influence of friction between both alloy wires can be avoided.

  Further, according to the present embodiment, since the U-turn portion is provided in the spiral groove and the shape memory alloy wire makes a U-turn, both ends of the shape memory alloy wire can be positioned close to each other, and the shape memory alloy The configuration for connecting the power supply to the wire can be simplified, and the device can be simplified and thereby reduced in size.

  Further, according to the present embodiment, the first moving lens 11 and the second moving lens 12 are held by the first lens holding frame 52 and the second lens holding frame 58, and the first lens holding frame 52 and the second lens holding are held. Guide pins 54, 60 protrude from the frame 58, and the guide pins 54, 60 pass through the long holes 56, 62 of the lens barrel 13 to form the first cam groove 78 and the second cam groove 80 on the inner peripheral surface of the cam cylinder 14. Since it is slidably inserted, the first moving lens 11 and the second moving lens 12 are slid linearly, that is, without rotating, as the cam cylinder 14 rotates, and the first cam groove 78 is inserted. The first moving lens 11 and the second moving lens 12 can be suitably moved.

  Further, according to the present embodiment, the position of the lens can be controlled with a simple control configuration in which the variable resistor 106 is connected to the controller 104, and the apparatus can be simplified and downsized accordingly. Compared with a configuration in which a lens position sensor and a feedback circuit are provided as in the prior art, the configuration of the circuit block is simple, space can be saved, and the size can be reduced.

  Further, according to the present embodiment, the lens driving circuit 102 performs PWM energization to the shape memory alloy wire, and the variable resistor 106 is configured to change the PWM energization pulse interval according to the resistance value change. The lens can be moved to a desired position by changing the resistance value of the variable resistor 106.

  In addition, according to the camera device 92 of the present embodiment, since the lens driving device 10 is provided, the entire camera can be downsized.

  In addition, the present embodiment is a driving device from another viewpoint, and the driving device includes a rotating body including a driving mechanism that moves a driven object along with the rotation. In the above embodiment, the rotating body is a cam cylinder, and the driven object is a lens. The driving device includes a first shape memory alloy wire 16 wound around the rotating body so as to rotate the rotating body in one direction according to a change in line length, and the rotating body as one direction due to a change in line length. A second shape memory alloy wire 18 wound around the rotating body in the opposite direction to the first shape memory alloy wire 16 so as to rotate in the opposite direction is provided. From this viewpoint, the driven object is not limited to a lens. With this configuration, the driven object can be moved with a simple and space-saving configuration in which the wire is wound around the rotating body, and thus the drive device can be downsized.

  In the driving device of the present embodiment, the first and second shape memory alloy wires 16 and 18 are respectively wound around the first and second spiral grooves provided on the outer side of the rotating body, The first and second spiral grooves have different depths and are provided in opposite directions. Thereby, the contact of the 1st, 2nd shape memory alloy wires 16 and 18 can be avoided, and the influence of both heat and friction can be avoided.

  Further, in the drive device of the present embodiment, the rotating body is the cam cylinder 14 provided with a cam structure as a drive mechanism inside, and with this configuration, the driven object can be driven by the cam structure.

  Further, in the driving apparatus of the present embodiment, the driven objects are the moving lenses 11 and 12, and the lens can be driven by this configuration. Further, the movable lenses 11 and 12 are held by the lens barrel 13, and a rotating body is rotatably provided outside the lens barrel 13, whereby the lens held by the lens barrel 13 is suitably moved. it can.

  In addition, the present embodiment is a driving device in another aspect. The driving device includes a first shape memory alloy wire 16 provided to move the driven object in one direction by changing the wire length, and And a second shape memory alloy wire 18 provided in the opposite direction to the first shape memory alloy wire 16 so as to move the driven object in a direction opposite to the one direction by changing the wire length. Slide terminals are provided at the ends of the first shape memory alloy wire 16 and the second shape memory alloy wire 18, a fixed terminal is provided so that the slide terminal slides, and a spring is provided between the slide terminal and the fixed terminal. It has been. The spring is deformable in the length direction of the first shape memory alloy wire 16 or the second shape memory wire 18. In the above-described embodiment, the driven object is a lens, but the driven object may be other than a lens within the scope of the present invention. Further, the shape memory alloy wire may not be wound around an object such as a cylinder. In this embodiment, as described above, a small driving device using a shape memory alloy wire is provided while the slide terminal slides with respect to the fixed terminal, the spring contracts, and the alloy wire is avoided from being cut. it can.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and it goes without saying that those skilled in the art can modify the above-described embodiments within the scope of the present invention.

  For example, in the above embodiment, the resistance value of the variable resistor 106 is changed in accordance with the user's button operation. However, the resistance value of the variable resistor 106 may be automatically changed. Move on.

  As described above, the lens driving device according to the present invention has an effect that the lens can be moved with a simple configuration and can be simplified and downsized, and is useful as a monitoring camera, a monitoring camera, or the like.

The perspective view of the lens drive device in an embodiment of the invention The perspective view of the lens drive device in an embodiment of the invention The front view of the lens drive device in embodiment of this invention Sectional view of the end of the first shape memory alloy wire Exploded view showing terminal portions of first shape memory alloy wire and second shape memory alloy wire Perspective view of the lens driving device with the cam barrel removed The perspective view which shows the cam in embodiment of this invention in detail Exploded view of a lens driving device in an embodiment of the present invention The perspective view of the camera apparatus in embodiment of this invention The figure which shows the lens drive control apparatus in embodiment of this invention Diagram showing pulse control Diagram showing the relationship between current and displacement of shape memory alloy wire A perspective view of the lens driving device when the lens is in the telephoto position Front view of the lens drive when the lens is in the telephoto position A perspective view of the lens driving device with the cam barrel removed when the lens is in the telephoto position A perspective view of the lens driving device when the lens is at a wide angle position Front view of the lens driving device when the lens is at a wide angle position A perspective view of the lens driving device with the cam barrel removed when the lens is at a wide angle position

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lens drive device 11 1st moving lens 12 2nd moving lens 13 Lens tube 14 Cam cylinder 16 1st shape memory alloy wire 18 2nd shape memory alloy wire 20 1st spiral groove 22 2nd spiral groove 30a, 30b, 30c, 30d Slide terminal 32a, 32b, 32c, 32d Fixed terminal 34a, 34b, 34c, 34d Spring 52 First lens holding frame 54 Guide pin 56 Long hole 58 Second lens holding frame 60 Guide pin 62 Long hole 78 First cam groove 80 Second cam groove 92 Camera device 100 Control device 102 Lens drive circuit 104 Controller 106 Variable resistor

Claims (11)

A lens barrel containing a moving lens;
A cam cylinder provided on the outside of the lens barrel so as to be rotatable, and provided with a cam structure on the inner side for guiding the moving lens in the optical axis direction along with the rotation;
A first shape memory alloy wire wound around the outside of the cam cylinder so as to rotate the cam cylinder in one direction by a change in wire length;
A second shape memory alloy wound around the outer side of the cam cylinder in the direction opposite to the first shape memory alloy wire so that the cam cylinder is rotated in a direction opposite to the one direction by a change in wire length. Lines and,
A lens driving device comprising:   A slide terminal is provided at an end of the first shape memory alloy wire and the second shape memory alloy wire, a fixed terminal is provided so that the slide terminal slides, and the slide terminal and the fixed terminal 2. The lens driving device according to claim 1, wherein a spring is provided between the first shape memory alloy wire and the second shape memory alloy wire so as to be deformable in a length direction therebetween.   The first and second shape memory alloy wires are respectively wound around first and second spiral grooves provided on the outer side of the cam cylinder, and the first and second spiral grooves are 3. The lens driving device according to claim 1, wherein the lens driving devices have different depths and are provided in opposite directions.   The moving lens is held by a lens holding frame, a guide pin protrudes from the lens holding frame, and the lens barrel is provided so as to extend in the optical axis direction and has a long hole through which the guide pin passes. 4. The lens driving device according to claim 1, wherein the cam structure of the cam barrel has a cam groove into which the guide pin is inserted. A lens driving circuit for supplying a current to the first and second shape memory alloy wires;
A controller for sending a control signal to the lens driving circuit;
A variable resistor connected to the controller and changing a control signal sent from the controller to the lens driving circuit to change a current supplied from the lens driving circuit to the first and second shape memory alloys; ,
The lens driving device according to claim 1, further comprising:   The lens driving circuit performs PWM energization on the first and second shape memory alloy wires, and the variable resistor changes a pulse interval of PWM energization according to a change in resistance value. Item 6. The lens driving device according to Item 5.   A camera device comprising the lens driving device according to claim 1. A rotating body provided with a driving mechanism for moving the driven object along with the rotation;
A first shape memory alloy wire wound around the rotating body so as to rotate the rotating body in one direction by a change in wire length;
A second shape memory alloy wire wound around the rotating body in a direction opposite to the first shape memory alloy wire so as to rotate the rotating body in a direction opposite to the one direction by a change in wire length; ,
A drive device comprising:   The first and second shape memory alloy wires are respectively wound around first and second spiral grooves provided on the outer side of the rotating body, and the first and second spiral grooves are The drive device according to claim 8, wherein the drive devices have different depths and are provided in opposite directions.   The drive device according to claim 8 or 9, wherein the rotating body is a cam cylinder provided with a cam structure as the drive mechanism inside.   A first shape memory alloy wire provided to move the driven object in one direction by changing the line length, and moving the driven object in a direction opposite to the one direction by changing the line length. And a second shape memory alloy wire provided in an opposite direction to the first shape memory alloy wire, and slides on end portions of the first shape memory alloy wire and the second shape memory alloy wire. A terminal is provided, a fixed terminal is provided so that the slide terminal slides, and a length of the first shape memory alloy wire or the second shape memory alloy wire is provided between the slide terminal and the fixed terminal. A drive device comprising a spring that is deformable in a direction.