JP2014142463A - Lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens driving device that stabilizes an operation of a lens holding frame by causing a desired restoring force to be exerted.SOLUTION: The lens driving device comprises: a driving section that moves a lens holding frame in an in-plane orthogonal to an optical axis; and a suction section 31 that has a suction magnet 51 provided at any one of a movable frame and the lens holding frame, has a first iron piece 41 provided at the other thereof, and causes the movable frame and the lens holding frame to be mutually sucked by pulling the suction magnet 51 and the first iron piece 41 each other in the optical axis. A tip end surface 41c of the first iron piece 41 facing the suction magnet 51 in the optical axis is configured in such a manner that a length in a radial direction D1 of a circle centering around the optical axis is shorter than a length in a tangential direction D2 of the circle, and is shorter than the length in the radial direction D1 of the circle centering around the optical axis of the suction magnet 51.

Description

  The present invention relates to a lens driving device that performs image blur correction by moving a lens in a direction orthogonal to an optical axis.

  Conventionally, there is Japanese Patent No. 4112215 as a technical document in such a field. This publication describes a blur correction device that corrects blur of a subject image by moving a lens frame in a direction orthogonal to the optical axis by a voice coil motor. The lens frame of the blur correction device is supported on the base member by urging the lens frame toward the base member with a spring that is stretched between the lens frame and the base member. More specifically, spring hook portions are provided at both ends of the spring, and a spring hook portion is provided at the lens frame and the base member. It is supported on the base member by a spring. As described above, the lens frame is supported by the spring, so that the lens frame can be prevented from floating in the optical axis direction, and the lens frame can be smoothly moved with respect to the base member.

Japanese Patent No. 4112215 Japanese Patent No. 3618952 Japanese Patent No. 3969927

  However, when the lens holding frame is supported by the spring as described above, the spring may buckle when a large load is applied, for example. The return force for movement may not be stable. Further, in the configuration in which the lens holding frame is supported by a plurality of springs, the spring force varies due to an error in the spring coefficient, which also causes a problem that the restoring force is not stable.

  Further, since the spring force can be generated only in one direction corresponding to the spring coefficient, springs having different spring coefficients must be used to adjust the return force. Therefore, when using springs with different spring coefficients, the springs must have different shapes or sizes, but in this case, the space for arranging the springs may be insufficient or excessive. . When the space for arranging the spring is small, it is necessary to use a small spring according to the space. However, it is difficult to manufacture the small spring, and when the small spring is used, it is difficult to adjust the spring coefficient. Therefore, it is difficult to exert a desired return force. As described above, since the desired restoring force cannot be exhibited and the restoring force is not stable, the operation of moving the lens holding frame in the direction orthogonal to the optical axis at the time of image blur correction and the center returning operation with respect to the frame of the lens holding frame are stable. There is a problem of not doing.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lens driving device that exhibits a desired restoring force and stabilizes the operation of a lens holding frame.

  In order to solve the above-described problems, the present invention provides a lens driving device having a lens holding frame that holds a lens and is movably supported in a plane perpendicular to the optical axis within the frame. It has a drive unit that moves in a plane orthogonal to the optical axis, an attraction magnet provided on one of the frame and the lens holding frame, and a magnetic body provided on the other, and is attracted in the direction of the optical axis. A suction part that attracts the frame and the lens holding frame to each other by attracting the magnet and the magnetic body, and the tip surface of the magnetic body facing the direction of the suction magnet and the optical axis is centered on the optical axis. The length of the circle in the radial direction is shorter than the length in the tangential direction of the circle and shorter than the length in the radial direction of the circle around the optical axis of the attracting magnet.

  According to the lens driving device of the present invention, in the plane orthogonal to the optical axis, the front end surface of the magnetic body faces the attracting magnet, and the radial length of the circle centering on the optical axis at the front end surface of the magnetic body is Is shorter than the length in the tangential direction and shorter than the length in the radial direction of the circle around the optical axis of the attraction magnet. Here, if the length in the radial direction on the tip surface of the magnetic body is approximately the same as the length in the tangential direction, the magnitude of the radial component and the tangential direction of the magnetic attractive force acting between the attracting magnet and the magnetic body The size of the component is approximately the same. When the tangential component of the magnetic attractive force increases, a force acts on the frame and the lens holding frame in the circumferential direction of the circle around the optical axis, and the rotational direction rotates around the optical axis. Power will work. Therefore, a force in the rotational direction is also generated when the lens holding frame is moved during image blur correction by the driving unit or when the lens holding frame is returned to the center. When the force in the rotation direction is generated in this way, there arises a problem that the position and operation of the lens holding frame with respect to the frame body become unstable. However, in the present invention, the radial length on the tip surface of the magnetic material is shorter than the tangential length and shorter than the radial length of the circle centered on the optical axis of the suction magnet. It is possible to reduce the tangential component of the magnetic attraction force by the magnet and the magnetic body and increase the radial component. Thus, by increasing the radial component of the magnetic attractive force generated by the magnetic body and the attractive magnet, a desired restoring force can be applied to the lens holding frame. Furthermore, by reducing the tangential component of the magnetic attractive force, the force in the rotational direction that rotates about the optical axis can be suppressed, so that the operation of the lens holding frame can be stabilized.

Further, the magnetic body has a plurality of claw portions that divide the front end surface, and the plurality of claw portions inserted into the frame body or the lens holding frame are juxtaposed in the tangential direction of the circle.
When the magnetic body is made flat without a claw, the tangential component of the magnetic attractive force becomes relatively large when the length of the tangential direction at the tip surface of the magnetic body is short. There arises a problem that the force in the rotation direction rotating around the axis becomes relatively large. On the other hand, in this invention, it has a some nail | claw part which divides the front end surface of a magnetic body, and these nail | claw parts are juxtaposed in the tangential direction. Therefore, even when the length in the tangential direction on the front end surface of the magnetic body is short, the problem that the force in the rotation direction becomes relatively large can be avoided by having the plurality of claw portions. Further, the operation of the lens holding frame can be stabilized by suppressing the force in the rotation direction.

Further, two suction portions are provided at positions symmetrical to the optical axis on a plane orthogonal to the optical axis.
According to this lens driving device, since two suction portions are provided at a position that is symmetric with respect to the optical axis, a suction force is applied to the lens holding frame from a position that is symmetric with respect to the optical axis. be able to. Therefore, the suction force generated between the frame and the lens holding frame can be stabilized, and the lens holding frame can be supported by the frame in a more stable state.

In addition, the suction part includes a first suction part and a second suction part, and a first line segment connecting the first suction part and the optical axis on the plane orthogonal to the optical axis is the second suction part and the optical axis. Is orthogonal to the second line segment connecting the two.
According to this lens driving device, the first line segment connecting the first suction unit and the optical axis is orthogonal to the second line segment connecting the second suction unit and the optical axis. The component in the radial direction of the force and the component in the radial direction of the magnetic attractive force by the second attraction unit are orthogonal to each other. Accordingly, since two types of suction forces orthogonal to each other can be applied to the lens holding frame, the position and operation of the lens holding frame with respect to the frame can be stabilized.

  According to the present invention, it is possible to stabilize the operation of the lens holding frame by exerting a desired restoring force.

It is a perspective view which shows one Embodiment of the lens drive device which concerns on this invention. It is a perspective view which shows the state which removed the cover part of the lens drive device of FIG. It is a disassembled perspective view which shows the lens drive device of FIG. It is a disassembled perspective view which shows the lens drive device of FIG. It is a perspective view which shows a movable frame and FPC. It is sectional drawing which shows a base part and a movable frame. It is sectional drawing which shows a movable frame and a lens holding frame. It is a perspective view which shows a lens holding frame. It is sectional drawing which shows a suction part. It is sectional drawing which shows the relationship between an attraction magnet and an iron piece. It is a perspective view which shows an attraction magnet and an iron piece. It is a graph which shows the relationship between the distance between a magnet and an iron piece, and magnetic attraction force. It is a perspective view which shows an attraction magnet and an iron piece. It is a graph which shows the relationship between the width | variety of an iron piece, and center return force. It is sectional drawing which shows the relationship between an attraction magnet and an iron piece.

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

  The lens driving device shown in FIG. 1 is used in a digital camera, a mobile phone, a smartphone, or the like that performs image blur correction, and is a CCD [Charge Coupled Device] image sensor or a CMOS [Complementary Metal Oxide Semiconductor] image sensor that is an image pickup device. It is placed in front and used.

  As shown in FIGS. 1 to 3, the lens driving device 1 includes a rectangular parallelepiped lid body 2, a rectangular base portion 3 for closing the opening of the lid body 2, and focus adjustment drive for adjusting the focus. The flexible printed circuit board (hereinafter referred to as FPC) 5 for adjusting the focus for securing the electrical connection between the unit 4 and the external circuit, the image blur correction driving unit (driving unit) 6 and the external circuit An image blur correction FPC 7 for securing a general connection, and a substantially cylindrical lens barrel 8 that accommodates at least one lens R. In the following description, the direction perpendicular to the optical axis C of the lens R is defined as the X axis, and the direction perpendicular to the optical axis C direction and the X axis is defined as the Y axis.

  The lid 2 is a box-shaped member having a circular opening 2a centered on the optical axis C of the lens R, and the base 3 is a rectangular frame having a circular opening 3a centered on the optical axis C. Shaped member. The lens barrel 8 holds the lens R in a state where the lens R is exposed from the opening 2a and the opening 3a. The base 3 has a protrusion 3b that protrudes from one side of the peripheral edge of the base 3 in the direction of the optical axis C. A rectangular opening 3c is formed at the center of the protrusion 3b. Yes. An H-shaped resin insulating plate 9 fixed to the front end portion 5a of the FPC 5 enters the opening 3c, and the resin insulating plate 9 closes the opening 3c.

  The FPC 7 has an extended portion 7 c extending outward from the lid body 2 and the base portion 3, and a bifurcated branch portion 7 a in a portion close to the lid body 2 and the base portion 3. As shown in FIG. 2, the bifurcated portion 7 a of the FPC 7 is fixed by being sandwiched between the locking projections 3 g of the base portion 3 inside the lid body 2. Further, the inner end of each of the branch portions 7a is fixed to a movable frame (frame body) 10, and the attracting force of the magnets 6a and 6b of the image blur correction drive unit 6 is amplified outside the tip portion 7b. The return yoke 11 is fixed. A Hall element 12 for magnetic detection is fixed to the tip 7b of the branching portion 7a on the surface opposite to the surface on which the return yoke 11 is fixed (see FIG. 3).

  The movable frame 10 is supported by the base portion 3 so as to be movable in the direction of the optical axis C. As shown in FIGS. 3 to 5, the movable frame 10 includes a circular opening 10 a centered on the optical axis C, an oval coil loading portion 10 b formed at each corner on one side, and a movable frame 10. And three ball mounting recesses 10c (see FIG. 5) into which spheres (supporting portions) 13 formed on the outer peripheral surface of the frame 10 enter. The lens barrel 8 is inserted into the opening 10a, and the coils 6c and 6d having an oval shape of the image blur correction driving unit 6 are fitted and fixed to the coil loading unit 10b. The movable frame 10 includes a magnet holding portion 10e that protrudes in the direction of the optical axis C on one side of the peripheral edge of the movable frame 10, and a magnet holding portion 10e that is a corner of the movable frame 10 with the optical axis C interposed therebetween. And two projecting portions 10f provided on the opposite side.

  The magnet holding portion 10e is formed in a crescent shape when viewed from the optical axis C direction, and both end portions 10g of the magnet holding portion 10e are notched in a semi-cylindrical shape and extend in the optical axis C direction. A ball receiving portion 10h is provided. Two spheres 15 enter one sphere receiving portion 10h, and one sphere 15 enters the other sphere receiving portion 10h, but two spheres 15 enter the other sphere receiving portion 10h. One sphere 15 may enter one of the ball receiving portions 10h.

  By the way, as shown in FIG. 4, the support portions 3 f formed at both ends of the protruding portion 3 b of the base portion 3 are formed with ball receiving portions 3 d cut out in a semi-cylindrical shape at three locations. Each ball receiving portion 3d is formed at a position corresponding to the above-described ball receiving portion 10h. Further, as shown in FIG. 6, the base 3 is formed with a fitting recess 3 e for fitting the coil 4 a and the yoke 16 inside the protrusion 3 b of the base 3. The coil 4a of the focus adjustment drive unit 4 and the two yokes 16 are fitted in the recess 3e. The coil 4a has a central portion 4b that forms an upper bottom portion of a trapezoid when viewed from the optical axis C direction, and end portions 4c that are located on both sides of the central portion 4b. The end portion 4c is in relation to the central portion 4b. It is bent about 45 degrees inside. The yokes 16 are respectively arranged outside the end portions 4c.

  Further, as shown in FIG. 5, the outer periphery of the magnet holding portion 10e of the movable frame 10 has a flat magnet fixing portion 10i extending in the optical axis C direction and the Y axis direction, and a magnet fixing portion 10i. And a magnet fixing portion 10k formed at an inclination of 45 degrees on the opposite side of the magnet fixing portion 10j with respect to the magnet fixing portion 10i. Magnets 4d, 4e, and 4f of the focus adjustment drive unit 4 are fixed to the magnet fixing units 10i, 10j, and 10k, respectively. In the state where the movable frame 10 is held by the base portion 3, as shown in FIG. 6, the central portion 4b of the trapezoidal coil 4a faces the outside of the magnet 4d, and the coil 4a is outside the magnets 4e and 4f. Each end 4c faces each other.

  In addition, a hall element 17 (see FIG. 3), which is a magnetic field detection element, is disposed inside the central portion 4b of the coil 4a, and the hall element 17 is fixed to the tip portion 5a of the FPC 5. Two iron leads 18 extending from the central portion 4b to the end portion 4c are arranged on both end sides of the Hall element 17, and the end portion 18a on the end portion 4c side of the lead 18 is shown in FIG. As shown in the figure, it is electrically connected to the coil wire of the end portion 4c in a state of extending to the outside of the end portion 4c.

  By the cooperation of the coil 4a and the magnets 4d, 4e, and 4f, the movable frame 10 can move in the direction of the optical axis C with respect to the base unit 3 to adjust the focal point and change the focal length. It becomes. Further, since the yoke 16 is provided outside the end portion 4c of the coil 4a, the yoke 16 fitted to the base portion 3 is attracted to the magnets 4d, 4e, 4f fixed to the movable frame 10, and the movable frame A suction force in a direction orthogonal to the optical axis C is generated with respect to the ten base portions 3. Further, the base 3 and the movable frame 10 are sucked in a state where the sphere 15 is interposed between the ball receiving portion 10h (see FIG. 5) of the movable frame 10 and the ball receiving portion 3d (see FIG. 4) of the base portion 3. Therefore, the movable frame 10 is slidably supported on the base portion 3 via the sphere 15.

  As shown in FIG. 4, the two protrusions 10 f provided at the corners of the movable frame 10 have engagement protrusions 10 m for joining the pressing plate 21 that prevents the lens holding frame 20 from lifting. Have. Engaging protrusions 10n for joining the pressing plates 21 are provided at both ends 10g of the magnet holding part 10e provided on the opposite side across the optical axis C of the protruding part 10f. The engagement protrusions 10m and 10n are engaged with the engagement holes 21a and 21b of the pressing plate 21, respectively. Thereby, the movable frame 10 and the pressing plate 21 are fixed in a state where the lens holding frame 20 is sandwiched.

  As shown in FIG. 7, the lens holding frame 20 holds the lens barrel 8 and is supported so as to be movable in the direction perpendicular to the optical axis C with respect to the movable frame 10. The lens holding frame 20 has a circular opening 20a for fitting the lens barrel 8, a magnet fitting hole 20b for fixing the magnets 6a and 6b, and a first for attracting the lens holding frame 20 and the movable frame 10 to each other. The magnet fitting recessed part 20c utilized for fixation of the 1st-3rd attraction | suction magnet 51,52,53 and the ball receiving recessed part 20d (refer FIG. 4) which receives the spherical body 13 are provided.

  Two magnet fitting holes 20b are provided at positions corresponding to the coil loading portion 10b (see FIG. 6) of the movable frame 10. The magnets 6a and 6b fitted in the magnet fitting hole 20b face the coils 6c and 6d fitted in the coil loading portion 10b in the optical axis C direction. The lens holding frame 20 can move in the direction orthogonal to the optical axis C with respect to the movable frame 10 and perform image blur correction by the cooperation of the coils 6c and 6d and the magnets 6a and 6b.

  As shown in FIG. 4, three ball receiving recesses 20 d are provided at positions corresponding to the ball mounting recesses 10 c (see FIG. 5) of the movable frame 10. In a state in which the lens holding frame 20 is disposed on the movable frame 10, the ball receiving recess 20d and the ball mounting recess 10c form a space large enough for the sphere 13 to enter. The lens holding frame 20 is supported by the sphere 13 so as to be movable with respect to the movable frame 10 by inserting the sphere 13 into the space formed by the ball receiving recess 20d and the ball mounting recess 10c. Further, when three spheres 13 are connected in a plane orthogonal to the optical axis C, an isosceles triangle is formed, and the lens holding frame 20 is supported by the movable frame 10 at three points. Therefore, the lens holding frame 20 can be moved with respect to the movable frame 10 in a stable state.

  Further, as shown in FIG. 3, a back yoke 25 having a crescent shape when viewed from the optical axis C direction is provided on the side of the holding plate 21 of the lens holding frame 20 in the optical axis C direction. The back yoke 25 is in close contact with the magnets 6a, 6b, 51, 52, 53 (see FIG. 7) of the lens holding frame 20 at the time of assembly.

  As shown in FIG. 8, three magnet fitting recesses 20c are provided, and each of the magnet fitting recesses 20c has a first attracting magnet 51 and a third attracting magnet of the same size magnetized with four poles. 53 and the first and third attraction magnets 51 and 53 are fitted into a second attraction magnet 52 that is larger in size than four poles. The first and third attraction magnets 51 and 53 are arranged at positions that are symmetric with respect to the optical axis C. A line segment M1 connecting the first attraction magnet 51 and the optical axis C is orthogonal to a line segment M2 connecting the second attraction magnet 52 and the optical axis C, and a line connecting the third attraction magnet 53 and the optical axis C. The minute M3 is orthogonal to the line M2 connecting the second attractive magnet 52 and the optical axis C.

  Further, as shown in FIG. 5, the movable frame 10 has a metal piece insertion portion 10 d that is a hole for inserting the claw portions of the fork-shaped first to third iron pieces (magnetic bodies) 41, 42, 43. In three places. Each metal piece insertion portion 10d is provided at a position corresponding to the magnet fitting recess 20c. Each metal piece insertion portion 10d has a claw portion of the first and third iron pieces 41 and 43 having the same size and a claw portion of the second iron piece 42 having a size larger than the first and third iron pieces 41 and 43. Inserted.

  As shown in FIG. 9, the claw portion 41 a of the first iron piece 41 inserted into the metal piece insertion portion 10 d of the movable frame 10 faces the first suction magnet 51 of the lens holding frame 20, and the optical axis C The first attracting magnet 51 and the first iron piece 41 attract each other in the direction, so that the movable frame 10 and the lens holding frame 20 attract each other. The first suction magnet 31 and the first iron piece 41 constitute the first suction part 31.

  Similarly to the above, the second iron piece 42 and the third iron piece 43 arranged on the movable frame 10 face the second attracting magnets 52 and 53 arranged on the lens holding frame 20, respectively, and are shown in FIG. In this way, the second iron piece 42 and the second attraction magnet 52 constitute the second attraction part 32, and the third iron piece 43 and the third attraction magnet 53 constitute the third attraction part 33. Further, the magnetic attractive force generated by the first to third attractive portions 31, 32, 33 is stronger than the magnetic attractive force generated by the magnets 6 a, 6 b of the image blur correction drive unit 6 and the return yoke 11. When the lens holding frame 20 is moved in the direction perpendicular to the optical axis C with respect to the movable frame 10, the lens holding frame 20 can be reliably moved to the center position of the movable frame 10.

  As shown in FIGS. 10, 11 (a), and 11 (b), the first iron piece 41 has a slit 41 b at the center, and is formed by dividing the tip end surface 41 c of the first iron piece 41. The fork-shaped two claw portions 41a are provided. Each tip surface 41c of the two claw portions 41a of the first iron piece 41 faces two poles of the first attraction magnet 51, and the tip surface 41c has a substantially rectangular shape. At this time, the other two poles of the first attractive magnet 51 are in close contact with the back yoke 25. Here, in the tip surface 41c of the claw portion 41a, the length L1 in the radial direction D1 of the circle around the optical axis C is shorter than the length L2 in the tangential direction D2. Further, the length L1 is shorter than the length L3 in the radial direction D1 of the circle around the optical axis C in the first attraction magnet 51. By setting the distal end surface 41c to such lengths L1 and L2, as shown in FIGS. 11 (a), 11 (b), and 12, the radial direction D1 generated in the first suction portion 31 is improved. The magnetic attractive force G1 in the tangential direction D2 generated in the first attractive portion 31 can be weakened by increasing the magnetic attractive force G1. In the graph of FIG. 12, the vertical axis indicates the magnitude of the magnetic attractive force G1, G2, and the horizontal axis indicates the distance between the first attractive magnet 51 and the first iron piece 41 in the radial direction D1 and the tangential direction D2. Show.

  Moreover, it replaced with the 1st iron piece 41 which has the nail | claw part 41a shown in FIG.13 (b), and the slit 41b, and was equipped with the flat plate part 141b as shown in FIG.13 (a) and FIG.15 (a). A flat iron piece 141 can be used. Here, as shown in FIG. 14, when the flat iron piece 141 is used and the length in the tangential direction D2 of the tip surface 141a of the iron piece 141 is long, the magnetic attractive force G11 in the radial direction D1 is tangential. It is larger than the magnetic attractive force G12 in the direction D2. Therefore, the magnetic attractive force G12 in the tangential direction D2 is suppressed, and the force in the rotational direction that rotates about the optical axis C can be suppressed.

  However, when the flat iron piece 141 is used and the length in the tangential direction D2 on the tip surface 141a of the iron piece 141 is short, the magnetic attraction force G12 in the tangential direction D2 becomes large. Therefore, when the length of the tangential direction D2 on the front end surface 141a of the iron piece 141 is short, the force in the rotational direction rotating around the optical axis C becomes large. On the other hand, when the 1st iron piece 41 which has the nail | claw part 41a is used, even if the length of the tangential direction D2 of the 1st iron piece 41 is short, the magnetic attraction force G2 of the tangential direction D2 hardly increases. Further, when the flat iron piece 141 is used, if the length in the tangential direction D2 is short, the difference X1 between the magnetic attractive force G11 in the radial direction D1 and the magnetic attractive force G12 in the tangential direction becomes small. When the first iron piece 41 having the portion 41a is used, the difference X2 between the magnetic attractive force G1 in the radial direction D1 and the magnetic attractive force G2 in the tangential direction D2 does not become smaller than the difference X1. Therefore, it is possible to maintain a state in which the magnetic attractive force G1 in the radial direction D1 is higher than the magnetic attractive force G2 in the tangential direction D2. Thus, when the 1st iron piece 41 which has the nail | claw part 41a is used, since the difference X2 of the magnetic attraction force G1 of the radial direction D1 and the magnetic attraction force G2 of the tangential direction D2 can be maintained, the flat iron piece 141 is obtained. Compared with the case of using, the force in the rotation direction rotating around the optical axis C can be suppressed.

  In addition, since the structure of the 2nd iron piece 42 in the 2nd suction part 32 and the structure of the 3rd iron piece 43 in the 3rd suction part 33 are the same as the structure of the 1st iron piece 41 in the 1st suction part 31, it demonstrates. Omitted.

  Next, the operation of the lens holding frame 20 will be described.

  If camera shake occurs when shooting with a device (for example, a camera) in which the lens driving device 1 is incorporated, the position of the optical axis C may change. In this case, a camera shake detection sensor such as a gyro sensor detects camera shake, and the control means (not shown) sends the drive signal of the lens holding frame 20 via the FPC 7 so that the position of the optical axis C is maintained at a predetermined position. Output to the coils 6c and 6d.

  As shown in FIG. 7, the magnet 6a and the coil 6c generate a driving force F1 that works in the direction of a straight line connecting the magnet 6a, the coil 6c, the opening 20a, and the center O of the lens R, and the lens holding frame. 20 is moved with respect to the movable frame 10 in the direction in which the driving force F1 acts. The magnet 6b and the coil 6d generate a driving force F2 that works in the direction of a straight line connecting the magnet 6b and the coil 6d and the center O, and move the lens holding frame 20 relative to the movable frame 10 in the direction in which the driving force F2 works. . By the movement of the lens holding frame 20 in the direction in which the driving forces F1 and F2 work, the position of the optical axis C is moved to a fixed position, and camera shake is corrected.

  As described above, in the lens driving device 1, the tip surface 41 c of the claw portion 41 a faces the first attracting magnet 51 and the tip surface 41 c of the first iron piece 41 as shown in FIGS. The length in the radial direction D1 of the circle centered on the optical axis C is shorter than the length in the tangential direction D2. Thus, the length in the radial direction D1 of the tip surface 41c of the first iron piece 41 is shorter than the length in the tangential direction D2 and longer than the length in the radial direction D1 of the circle centered on the optical axis of the first attracting magnet 51. Since it is shortened, the magnetic attractive force G2 in the tangential direction D2 by the first attractive magnet 51 and the first iron piece 41 can be reduced and the magnetic attractive force G1 in the radial direction D1 can be increased. Thus, by increasing the magnetic attractive force G1 in the radial direction D1 generated by the first iron piece 41 and the first attractive magnet 51, a desired restoring force can be applied to the lens holding frame 20. Furthermore, by reducing the magnetic attraction force G2 in the tangential direction D2, the force in the rotation direction that rotates about the optical axis C can be suppressed, so that the operation of the lens holding frame 20 can be stabilized.

  Further, as shown in FIG. 14, when a flat iron piece 141 is used instead of the first iron piece 41, the tangential direction when the length in the tangential direction D <b> 2 direction on the tip surface 141 a of the iron piece 141 is short. A problem arises that the magnetic attractive force G12 of D2 becomes large, and the force in the rotational direction rotating about the optical axis C becomes relatively large. On the other hand, when it has the claw part 41a which divides the front end surface 41c of the 1st iron piece 41 and the claw part 41a is juxtaposed in the tangential direction D2, the length of the tangential direction D2 in the front end surface 41c of the 1st iron piece 41 Even if the length is short, the magnetic attractive force G2 in the tangential direction D2 is suppressed, and the force in the rotational direction that rotates about the optical axis C is suppressed, so that the force in the rotational direction becomes relatively large. Can be avoided.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  As shown in FIG. 7, the three first to third suction parts 31, 32, 33 are arranged, but the number and arrangement positions of the suction parts are not limited to this, and for example, with respect to the optical axis C You may arrange | position only the 1st suction part 31 and the 3rd suction part 33 which are located symmetrically. In this case, since the two first suction parts 31 and the third suction part 33 are provided at positions that are symmetric with respect to the optical axis C, the lens holding frame 20 is moved from a position that is symmetric with respect to the optical axis C. Can give suction power. Therefore, the suction force generated between the movable frame 10 and the lens holding frame 20 can be stabilized, and the lens holding frame 20 can be supported by the movable frame 10 in a more stable state.

  Further, only the first suction part 31 and the second suction part 32 may be arranged. In this case, the first line segment L1 connecting the first suction part 31 and the optical axis C is orthogonal to the second line segment L2 connecting the second suction part 32 and the optical axis C. The radial magnetic attractive force and the radial magnetic attractive force by the second attractive portion 32 are orthogonal to each other. Therefore, two types of suction forces orthogonal to each other can be applied to the lens holding frame 20, so that the position and operation of the lens holding frame 20 with respect to the movable frame 10 can be stabilized.

  Moreover, it can replace with the 1st iron piece 41 which has the nail | claw part 41a, and can use the iron piece of various shapes. For example, in a plane orthogonal to the optical axis C, an iron piece 241 having a claw portion 241a with both ends protruding from the first attracting magnet 51 as shown in FIG. 15B, or as shown in FIG. A flat iron piece 341 having both ends protruding from the first attraction magnet 51 may be used. Further, the number of claw portions may be three or more. Furthermore, the shape of the surface of the iron piece facing the attracting magnet may not be rectangular, but may be oval or oval.

  In addition, the first to third suction magnets 51, 52, and 53 are disposed on the lens holding frame 20, and the first to third iron pieces 41, 42, and 43 are disposed on the movable frame 10. The arrangement relationship between 51, 52, 53 and the first to third iron pieces 41, 42, 43 may be reversed. Further, instead of the first to third iron pieces 41, 42, 43, a magnetic body other than iron may be used.

  The lens holding frame 20 is supported so as to be movable in the direction orthogonal to the optical axis C with respect to the movable frame 10, but is supported so as to be movable in the direction orthogonal to the optical axis C with respect to the base portion 3 forming the frame. May be. Further, the lens R may be held with respect to the lens holding frame 20 so as to be movable in the direction of the optical axis C.

DESCRIPTION OF SYMBOLS 1 ... Lens drive device, 3 ... Base part, 6 ... Image blur correction drive part (drive part), 10 ... Movable frame (frame body), 20 ... Lens holding frame, 31 ... 1st suction part, 32 ... 2nd suction , 33 ... third suction part, 41 ... first iron piece (magnetic body), 41a ... claw part, 41c ... tip surface, 42 ... second iron piece (magnetic body), 43 ... third iron piece (magnetic body), 51 ... 1st suction magnet, 52 ... 2nd suction magnet, 53 ... 3rd suction magnet, C ... Optical axis, D1 ... Radial direction, D2 ... Tangent direction, R ... Lens.

Claims (4)

A lens driving device having a lens holding frame that holds a lens and is movably supported in a plane perpendicular to the optical axis in the frame,
A drive unit for moving the lens holding frame in a plane perpendicular to the optical axis;
It has an attraction magnet provided on one of the frame and the lens holding frame and a magnetic body provided on the other, and the attraction magnet and the magnetic body attract each other in the direction of the optical axis. A suction part that sucks the frame and the lens holding frame together,
The tip surface of the magnetic body facing the suction magnet and the direction of the optical axis has a length in the radial direction of the circle centered on the optical axis that is shorter than the length in the tangential direction of the circle, and the suction magnet The lens driving device is characterized in that it is shorter than the length in the radial direction of the circle centered on the optical axis. The magnetic body has a plurality of claw portions that divide the tip surface,
The lens driving device according to claim 1, wherein the plurality of claw portions inserted into the frame body or the lens holding frame are juxtaposed in a tangential direction of the circle.   3. The lens driving device according to claim 1, wherein two suction portions are provided at positions symmetrical with respect to the optical axis on a plane orthogonal to the optical axis. The suction part includes a first suction part and a second suction part,
In a plane orthogonal to the optical axis, a first line segment connecting the first suction part and the optical axis is orthogonal to a second line segment connecting the second suction part and the optical axis. The lens driving device according to claim 1 or 2, characterized in that

Images