JP2013088684A - Shake correction device, lens barrel, and optical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shake correction device that is small in size and low in cost and that reduces rotation of a shift member within a plane orthogonal to an optical axis.SOLUTION: A shake correction device comprises: the shift member holding a lens; a first drive part configured to move the shift member with respect to a body part in a first direction within a plane orthogonal to the optical axis; and a second drive part configured to the shift member in a second direction different from the first direction. The first drive part is composed by arranging a first magnet, a first coil, and a first yoke and the second drive part is composed by arranging a second magnet, a second coil, and a second yoke, in that order in the direction of the optical axis. The first yoke has a first projection part projecting in the direction of the optical axis and toward the first magnet. The second yoke has a second projection part projecting in the direction of the optical axis and toward the second magnet. As viewed in the direction of the optical axis, the width of the first projection part in a first direction that is far from the second yoke is greater than that close to the second yoke, and the width of the second projection part in the second direction far from the first yoke is greater than that close to the first yoke.

Description

  The present invention relates to a shake correction apparatus that shifts a lens to correct image shake.

  2. Description of the Related Art Conventionally, a shift unit (blur correction device) that shifts a lens to correct image blur caused by camera shake in an optical apparatus such as a digital camera or a digital video camera is known. Patent Document 1 discloses a shake correction apparatus that moves a correction lens group. This shake correction apparatus is a so-called moving coil type shift unit, in which a driving magnet is disposed on a fixed base member, and a yoke and a coil are disposed on a movable shift member.

  Since a magnetic attractive force acts between the driving magnet and the yoke, there is a magnetically balanced position between the driving magnet and the yoke. Therefore, when the positional relationship between the drive magnet and the yoke changes from the balanced position, a force (retraction force) for returning to the original position works. As a result, in the shift unit including two drive units for driving the shift member in the vertical direction (pitch direction) and the horizontal direction (yaw direction) in a plane orthogonal to the optical axis, one position change is pulled back to the other. Generate power.

  Patent Document 1 discloses a shake correction device that reduces a pull back force in a pitch direction driving unit. In this shake correction apparatus, a protrusion protruding in the optical axis direction is provided on the yoke. The magnitude of the magnetic force is inversely proportional to the square of the distance. For this reason, when the shift member moves in the plane orthogonal to the optical axis and the distance between the drive magnet and the protrusion changes, the pulling force acting between the drive magnet and the protrusion is a direction that promotes the movement. To work.

  However, in this case, the pulling force is generated in the yaw direction drive unit, so that a moment for rotating the shift member in the plane orthogonal to the optical axis is generated. For this reason, the shift member freely rotates during the shake correction operation. When the shift member comes into contact with the fixed member due to the rotational motion, a collision sound is generated and the image may be disturbed. Further, if the component is damaged by the contact, there is a case where the subsequent drive of the shift member is hindered.

  Patent Document 2 discloses a shake correction apparatus provided with a guide shaft for restricting rotation of a shift member in a plane orthogonal to an optical axis.

JP 2002-196382 A Japanese Patent No. 3229899

  However, when a guide shaft as disclosed in Patent Document 2 is newly provided, downsizing of the shake correction device is hindered. Further, the cost reduction becomes difficult due to the complicated configuration of the apparatus and the increase in the number of parts.

  Therefore, the present invention provides a shake correction device, a lens barrel, and an optical apparatus that reduce the rotation of the shift member in the plane orthogonal to the optical axis at a small size and at low cost.

  The shake correction device as one aspect of the present invention includes a shift member that holds a lens, a first drive unit that moves the shift member in a first direction within a plane perpendicular to the optical axis with respect to the main body unit, A second driving unit that moves the shift member in a second direction different from the first direction in a plane orthogonal to the optical axis with respect to the main body unit, the first driving unit including a first magnet, The first coil and the first yoke are sequentially arranged in the optical axis direction, and the second driving unit sequentially arranges the second magnet, the second coil, and the second yoke in the optical axis direction. The first yoke has a first protrusion protruding in the optical axis direction and toward the first magnet, and the second yoke protrudes in the optical axis direction and toward the second magnet. A second protrusion having the second yaw when viewed in the optical axis direction; The width of the first protrusion in the first direction on the side far from the first yoke is larger than the width on the side near the second yoke, and the width of the second protrusion in the second direction on the side far from the first yoke. The width is larger than the width on the side close to the first yoke.

  A lens barrel according to another aspect of the present invention includes the shake correction device.

  An optical apparatus according to another aspect of the present invention includes the lens barrel.

  Other objects and features of the present invention are illustrated in the following examples.

  According to the present invention, it is possible to provide a shake correction device, a lens barrel, and an optical apparatus that reduce the rotation of the shift member in the plane orthogonal to the optical axis at a low cost.

It is a disassembled perspective view of the shift unit in a present Example. It is sectional drawing of the lens barrel provided with the shift unit in a present Example. It is a disassembled perspective view of the lens barrel provided with the shift unit in a present Example. It is sectional drawing of the pitch direction drive part of the shift unit in a present Example. It is explanatory drawing of the pull back force of the shift unit in a prior art example. It is explanatory drawing of the pullback force of the shift unit in a present Example. It is a figure which shows the yoke shape of another form in a present Example. It is a block diagram of the optical apparatus provided with the lens barrel in a present Example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and redundant description is omitted.

  First, with reference to FIG. 2 and FIG. 3, the lens barrel provided with the shift unit (shake correction apparatus) in the present embodiment will be described. FIG. 2 is a cross-sectional view of a lens barrel provided with a shift unit. FIG. 3 is an exploded perspective view of a lens barrel provided with a shift unit. The lens barrel 100 of the present embodiment is configured to be attachable (replaceable) to an imaging apparatus body (optical device) such as a video camera or a digital still camera. However, the present embodiment is not limited to this, and can also be applied to a camera system in which a lens barrel and an imaging apparatus main body are integrally configured.

  The lens barrel 100 of the present embodiment is a lens barrel having a variable magnification optical system having a four-group configuration having convex and concave projections. L1 is a fixed first group lens. L2 is a second group lens that performs a zooming operation by moving in the direction of the optical axis OA (optical axis direction). L3 is a third lens group (correction lens group) that performs shake correction by moving in a plane orthogonal to the optical axis OA (in the optical axis orthogonal plane). L4 is a fourth group lens that performs a focusing operation by moving in the optical axis direction.

  Reference numeral 1 denotes a fixed lens barrel that holds the first group lens L1. Reference numeral 2 denotes a second group moving frame that holds the second group lens L2. Reference numeral 3 denotes a shift unit (shake correction device) that moves the third lens unit L3 in the direction orthogonal to the optical axis (within the plane orthogonal to the optical axis). Reference numeral 4 denotes a fourth group moving frame that holds the fourth group lens L4. Reference numeral 5 denotes an image sensor holder to which an image sensor such as a CCD or CMOS sensor is fixed. The fixed barrel 1 is screwed to the front fixed barrel 6, and the image sensor holder 5 and the front fixed barrel 6 are screwed to the rear fixed barrel 7. Reference numerals 8, 9, 10, and 11 denote guide bars, which are positioned and fixed by a front fixed cylinder 6 and a rear fixed cylinder 7. The guide bars 8 and 9 support the moving frame 2 so as to be movable in the optical axis direction. The guide bars 10 and 11 support the moving frame 4 so as to be movable in the optical axis direction. The shift unit 3 is positioned with respect to the rear fixed cylinder 7 and fixed with screws.

  A diaphragm device 12 changes the aperture diameter of the optical system. The diaphragm device 12 is a so-called guillotine diaphragm device that moves two diaphragm blades in opposite directions to change the aperture diameter. Reference numeral 13 denotes a VCM (voice coil motor) for driving the fourth lens unit L4 in the optical axis direction to perform a focusing operation. The VCM 13 includes a magnet 13a, yokes 13b and 13c, and a coil 13d. By passing a current through the coil 13d, a Lorentz force is generated in the coil 13d, and the coil 13d can be driven in the optical axis direction. The coil 13d is fixed to the moving frame 4, and the moving frame 4 is driven in the optical axis direction simultaneously with the driving of the coil 13d.

  Reference numeral 14 denotes a zoom motor for driving the second group lens L2 in the optical axis direction to perform a zooming operation. The zoom motor 14 has a lead screw 14a coaxial with the rotating rotor. A rack 2a attached to the second group moving frame 2 is meshed with the lead screw 14a, and the second group lens L2 is driven in the optical axis direction by the rotation of the rotor. In addition, the torsion coil spring 2b moves the second group moving frame 2, the guide bars 8 and 9, the rack 2a, and the lead screw 14a together to prevent backlash of fitting or meshing. Yes. In the VCM 13, the yoke 13b is press-fitted and fixed to the rear fixed cylinder 7, and the magnet 13a and the yoke 13c are fixed to the yoke 13b by magnetic force. The zoom motor 14 is fixed to the rear fixed cylinder 7 with two screws.

  Reference numeral 15 denotes a photo interrupter that optically detects the movement of the oblique light portion 2c formed in the second group moving frame 2 in the optical axis direction. The photo interrupter 15 is used as a zoom reset switch for detecting that the second group lens L2 is located at the reference position. Reference numeral 16 denotes an optical sensor including a light emitting unit and a light receiving unit. The optical sensor 16 irradiates the light from the light emitting unit onto the scale 17 that is bonded and fixed to the fourth group moving frame 4, and reads the light reflected by the scale 17 by the light receiving unit of the optical sensor 16. The position of the lens L4 is detected.

  Next, the configuration of the shift unit 3 (shake correction device) that moves the third lens unit L3 in the direction orthogonal to the optical axis will be described with reference to FIGS. FIG. 1 is an exploded perspective view of the shift unit 3. FIG. 4 is an enlarged cross-sectional view of the pitch direction drive unit (first drive unit) of the shift unit 3, and shows a case where the center of the third lens L3 is on the optical axis OA.

  The third group lens L3 is driven in a plane orthogonal to the optical axis by a pitch direction drive unit (pitch direction drive actuator) and a yaw direction drive unit (yaw direction drive actuator). The actuator for driving in the pitch direction is an actuator that corrects image blur due to an angle change in the pitch direction (vertical direction of the lens barrel). The actuator for driving the yaw direction is an actuator for correcting image blur due to an angle change in the yaw direction (horizontal direction of the lens barrel). The actuator for driving in the pitch direction and the actuator for driving in the yaw direction are independently driven and controlled based on information from the position sensor and the shake detection sensor in the pitch direction and the yaw direction, respectively. Further, the actuator and position sensor for the pitch direction and the actuator and position sensor for the yaw direction are arranged so as to form an angle that is substantially orthogonal (90 degrees). However, since these configurations themselves are the same, only the configuration in the pitch direction will be described below, and the configuration in the yaw direction will be omitted. Unless otherwise specified, a suffix p is attached to elements in the pitch direction, and a suffix y is attached to elements in the yaw direction.

  Reference numeral 22 denotes a shift frame that holds the third lens unit L3 and is displaced in the direction orthogonal to the optical axis in order to correct shake. Reference numeral 18 denotes a magnet base. A magnet 24p serving both for driving and for position detection is press-fitted and held in the magnet base 18. By inserting the magnet 24p into the magnet base 18 and incorporating it, the relative positional relationship between the magnet base 18 and the magnet 24p does not shift after the assembly. The magnet base 18 is fixed to the shift moving frame 22 with screws. For this reason, the position of the magnet 24p, which also serves as a position detection function, is determined to be a fixed position with respect to the shift moving frame 22 holding the third group lens L3. The position can be detected accurately. The shift moving frame 22 and the magnet base 18 are coupled and fixed by screws in a state where the metal plate 19 is sandwiched between them. As a material of the metal plate 19, for example, stainless steel is suitably used. In this embodiment, the shift member 22 and the magnet base 18 constitute a shift member that holds the third group lens L3.

  Reference numeral 20 denotes a plurality of balls disposed between the shift base 21 (main body portion) and the magnet base 18. In this embodiment, three balls 20 are arranged around the optical axis in the plane orthogonal to the optical axis. As will be described later, these three balls 20 are sandwiched between the shift base 21 and the magnet base 18 by the magnetic attractive force acting between the magnet 24p and the yoke 29p and between the magnet 24y and the yoke 29y. Has been. The metal plate 19 described above is disposed between the ball 20 and the magnet base 18. Due to the provision of the metal plate 19, when the lens barrel receives an impact, the magnet base 18 which is a molded part is dented by the ball 20, and a shift due to wear caused by a long-time shake correction operation drive occurs. Deterioration of the drive characteristics of the unit 3 can be prevented. The ball 20 is rotatably held by a ball folder portion 21 a formed on the shift base 21. The material of the ball 20 is preferably stainless steel or a non-magnetic material such as SUS304 so as not to be attracted to the magnet 24 disposed in the vicinity thereof.

  The force for reliably bringing the ball 20 into contact with the shift base 21 (the end surface in the optical axis direction of the ball folder portion 21a) and the magnet base 18 (metal plate 19) is between the magnet 24p and the yoke 29p (fixed yoke). It is the magnetic attractive force that acts. By urging the magnet base 18 toward the shift base 21 by this magnetic attractive force, the three balls 20 are against the three end portions of the three ball folder portions 21 a in the optical axis direction and the metal plate 19. Contact in the pressed state. Each surface with which the three balls 20 abut is spread in a direction orthogonal to the optical axis OA of the photographing optical system. The nominal diameters of the three balls 20 are the same. Therefore, by reducing the positional difference in the optical axis direction between the end faces in the optical axis direction in the three ball folder portions 21a, the third lens group L3 held by the shift moving frame 22 is caused to fall with respect to the optical axis OA. Without being moved in the plane orthogonal to the optical axis. As described above, in this embodiment, the plurality of balls 20 roll in the plane orthogonal to the optical axis, so that the shift frame 22 and the magnet base 18 shift and move in the plane orthogonal to the optical axis.

  Next, an actuator (drive unit) that drives the magnet base 18 (shift member) and the third lens unit L3 will be described. The actuator according to the present embodiment includes a first drive unit and a second drive unit that move the shift member in a first direction and a second direction in a plane orthogonal to the optical axis with respect to the main body (shift base 21). . In this embodiment, the first direction and the second direction are directions orthogonal to each other in a plane orthogonal to the optical axis. For example, the first direction is the pitch direction and the second direction is the yaw direction. It is not limited. The first drive unit is configured by sequentially arranging a magnet 24p (first magnet), a coil 28p (first coil), and a yoke 29p (first yoke) in the optical axis direction. Similarly, the second drive unit is configured by sequentially arranging a magnet 24y (second magnet), a coil 28y (second coil), and a yoke 29y (second yoke) in the optical axis direction.

  As shown in FIG. 4, the magnet 24p is dipole magnetized in the radial direction from the optical axis, and the yoke 23p closes the magnetic flux on the front side of the magnet 24p in the optical axis direction. The yoke 23p is attracted and fixed to the magnet 24p. The yoke 23p has a protrusion 30p (first protrusion) that protrudes in the optical axis direction and toward the magnet 24p (first magnet). Similarly, the yoke 23y has a protrusion 30y (second protrusion) that protrudes in the optical axis direction and toward the magnet 24y (second magnet side).

  The coil 28p is bonded and fixed to the shift base 21, and the yoke 29p is a fixed yoke for closing the magnetic flux on the rear side in the optical axis direction of the magnet 24p. The yoke 29p is disposed on the opposite side of the coil 28p from the magnet 24p and is held by the shift base 21. The magnet 24p, the yoke 23p, the yoke 29p, and the coil 28p constitute a magnetic circuit. As a material used for the yoke 23p and the yoke 29p, a magnetic material having a high magnetic permeability, such as SPCC, is suitably used. When a current is passed through the coil 28p, the Lorentz force due to the repulsion between the magnetic lines of force generated in the magnet 24p and the coil 28p is substantially perpendicular to the magnetization boundary of the magnet 24p (the direction that is substantially orthogonal). Occur. By this force, the magnet base 18 moves in the direction perpendicular to the optical axis. Thus, the actuator of the present embodiment is a so-called moving magnet type actuator.

  Since the actuator having such a configuration is arranged in each of the vertical direction and the horizontal direction, the magnet base 18 and the shift movement frame 22 can be driven in two optical axis orthogonal directions that are substantially orthogonal to each other. Further, the magnet base 18 and the shift moving frame 22 can be freely moved within a predetermined range in the plane orthogonal to the optical axis by the vertical and horizontal drive synthesis. The friction when the magnet base 18 operates in the direction perpendicular to the optical axis is between the ball 20 and the metal plate 19 and between the ball 20 and the ball folder portion 21a as long as the ball 20 does not contact the wall of the ball folder portion 21a. It is only rolling friction that occurs during each period. For this reason, the magnet base 18 (that is, the shift moving frame 22 that holds the third lens unit L3) can move smoothly in the plane orthogonal to the optical axis despite the above-mentioned attractive force acting, and the minute Movement amount control is also possible. Note that the frictional force can be further reduced by applying lubricating oil to the balls 20.

  Next, position detection of the magnet base 18 and the third group lens L3 will be described. Reference numeral 27p denotes a Hall element that converts the magnetic flux density into an electric signal. The hall element 27p is soldered to the FPC 26 (flexible print cable). The FPC 26 is positioned and fixed with respect to the shift base 21. Further, by fixing the FPC pressing metal fitting 25 to the shift base 21 with screws, the FPC 26 is prevented from floating and the Hall element 27p is prevented from being displaced. The hall element 27p and the magnet 24p constitute a position sensor that detects the positions of the magnet base 18 and the third group lens L3. When the magnet base 18 and the third group lens L3 are driven in the vertical direction or the horizontal direction, a change in the magnetic flux density of the magnet 24p is detected by the Hall element 27p, and an electrical signal indicating the change in the magnetic flux density is output. A control circuit (not shown) detects the positions of the magnet base 18 and the third group lens L3 based on the output of the Hall element 27p. The magnet 24p is a drive magnet and is also used as a position detection magnet.

  The attractive force acting between the magnet 24p and the yoke 29p is proportional to the reciprocal of the strength of the magnetic charge of the two objects and the square of the distance, as shown by Coulomb's law. For this reason, when the magnet 24p is at the center position of the drive unit, the attracting forces in the pitch direction and the yaw direction are balanced in the respective directions. That is, the attracting forces 40a and 40b acting between the magnet 24p and the protruding portion 30p of the yoke 29p are balanced, and the positional relationship between the magnet 24p as a driving magnet and the yoke 29p is determined. At this time, the pulling force 50p in the pitch direction (upward in FIG. 4) is substantially zero, and the pulling force 50y in the yaw direction (downward in the drawing in FIG. 4) is also substantially zero.

  Next, with reference to FIG. 5, the relationship between the movement of the shift unit (drive unit and shift member) in the conventional example and the pull back force due to the suction force will be described. FIG. 5 is an explanatory diagram of the pull back force of the shift unit in the conventional example. 5A to 5C show the pitch direction drive unit, and FIGS. 5D and 5E show the pitch direction and yaw direction drive unit and the shift member, respectively, on the front side (subject side) of the shift unit. It is the figure seen from. In FIG. 5, members other than the magnet 240 (driving magnet), the yoke 290, the protrusion 300, and the third group lens L3 (correction lens) are omitted. As shown in FIG. 5, the projection 300 of the yoke 290 in the conventional example has a substantially rectangular shape projected onto the plane orthogonal to the optical axis. Further, the pulling forces acting on the four corners of the magnet 240p are referred to as pulling forces 410, 420, 430, and 440, respectively. Similarly, pulling forces acting on the four corners of the magnet 240y are referred to as pulling forces 450, 460, 470, and 480, respectively.

  FIG. 5A shows the pitch direction drive unit when the center of the third lens unit L3 is on the optical axis. At this time, since the magnet 240p is in the center position with respect to the yoke 290p, the pullback forces 410, 420, 430, and 440 at the four corners are in a balanced state. That is, the pullback force 500p in the pitch direction and the pullback force 500y in the yaw direction are substantially zero. FIG. 5B shows the pitch direction driving unit in the case where the center of the third lens unit L3 has moved by a distance d in the pitch direction (upward). As described above, since the magnitude of the magnetic force is inversely proportional to the square of the distance, the pullback forces 430p and 440p are larger than the pullback forces 410p and 420p acting on the protrusion 300p. Therefore, the pullback force 500p works in a direction that promotes movement. Here, since the shapes of the magnet 240p and the protrusion 300p are symmetrical with respect to the driving direction, the magnitudes of the pullback forces 410p and 420p are substantially equal to each other, and the magnitudes of the pullback forces 430p and 440p are also substantially equal. Further, since it does not move in the yaw direction, the pullback force 500y is substantially 0 as in the case of FIG.

  Next, FIG. 5C shows the pitch direction driving unit when the center of the third lens unit L3 moves by a distance d in the yaw direction. Also in this case, the positional relationship between the magnet 240p and the protrusion 300p changes to generate the pull back force 500y. That is, a force in a direction to return to the state of FIG. Here, since the shapes of the magnet 240p and the protrusion 300p are symmetrical with respect to the driving direction, the magnitudes of the pullback forces 410y and 430y are substantially equal, and the magnitudes of the pullback forces 420y and 440y are also substantially equal. Further, since it does not move in the pitch direction, the pullback force 500p is substantially 0 as in the case of FIG.

  FIG. 5D shows a case where the center of the third lens group L3 has moved by a distance d in the pitch direction. As described with reference to FIG. 5 (b), the pulling force 500p in the pitch direction acts on the magnet 240p, but the shift member can be moved by the Lorentz force 600 generated by energizing the coil (not shown). It is. On the other hand, as described with reference to FIG. 5C, the pull-back force 510y acts on the yaw-side magnet 240y. Due to the pull-back force 510y, a rotational moment about an axis parallel to the optical axis acts on the shift member. As a result, as shown in FIG. 5D, a counterclockwise roll motion is generated in the shift member. Then, the shift member stops at a position where all of the rotational moment, the pullback force, the Lorentz force, and the like are balanced.

  FIG. 5E shows a case where the center of the third lens unit L3 has moved by a distance d in the direction opposite to that in FIG. Similarly to FIG. 5D, a rotational moment centering on an axis parallel to the optical axis acts on the shift member by the pull back force 510y generated in the yaw-side magnet 240y and the protrusion 300y. As a result, as shown in FIG. 5E, a clockwise roll operation occurs in the shift member. Then, the shift member stops at a position where all of the rotational moment, the pullback force, the Lorentz force, and the like are balanced.

  Next, with reference to FIG. 6, the relationship between the movement of the shift member (driving unit and shift member) and the pull back force due to the suction force in this embodiment will be described. 6A to 6C show the pitch direction drive unit, and FIGS. 6D and 6E show the pitch direction and yaw direction drive unit and the shift member, respectively, on the front side (subject side) of the shift unit. It is the figure seen from. In FIG. 6, members other than the magnet 24 (driving magnet), the yoke 29, the protrusion 30, and the third group lens L3 (correction lens group) are omitted. In addition, as for the projection part 30 in a present Example, as FIG. 6 shows, the projection shape (optical axis direction view) to an optical axis orthogonal surface becomes a substantially trapezoid. Here, the pulling forces acting on the four corners of the magnet 24p are referred to as pulling forces 41, 42, 43, and 44, respectively, as shown in FIG. Similarly, pulling forces acting on the four corners of the magnet 24y are pulling forces 45, 46, 47, and 48, respectively.

  FIG. 6A shows the pitch direction drive unit when the center of the third lens unit L3 is on the optical axis. At this time, since the magnet 24p is at the center position in the driving direction axis with respect to the protrusion 30p, the pulling force 41 and the pulling force 43 at the four corners, and the pulling force 42 and the pulling force 44 are substantially balanced. That is, the pullback force 50p in the pitch direction and the pullback force 50y in the yaw direction are substantially zero.

  FIG. 6B shows a pitch direction drive unit in the case where the center of the third lens unit L3 has moved a distance d in the upward direction of the pitch. As described above, since the magnitude of the magnetic force is inversely proportional to the square of the distance, the pulling force acting between the protrusions 30p is the resultant force of the pulling forces 43p and 44p rather than the resultant force of 41p and 42p. large. Accordingly, the pullback force 50p works in a direction that promotes movement. Here, in the projection shape on the plane orthogonal to the optical axis, the magnitudes of the pullback forces 41p, 42p, 43p, 44p of the magnet 24p are 44p> 43p> 42p> 41p due to the difference in the shortest distance from the protrusion 30p. It is in. Accordingly, since the magnet 24p is magnetically stabilized with respect to the protrusion 30p, the rotational force 52 acts so that the magnet 24p rotates in the clockwise direction (the direction of the white arrow in FIG. 6B).

  Next, FIG. 6C shows the pitch direction driving unit when the center of the third lens unit L3 moves by a distance d in the yaw direction. Also in this case, the positional relationship between the magnet 24p and the protrusion 30p changes and a pullback force is generated. That is, a force in a direction to return to a magnetically stable state works. Here, since the shapes of the magnet 24p and the protrusion 30p are symmetrical with respect to the driving direction, the magnitudes of the pullback forces 41y and 43y are substantially equal to each other, and the magnitudes of the pullback forces 42y and 44y are substantially equal to each other. Further, since it does not move in the pitch direction, the pulling back force 50p is substantially 0 as in the case of FIG.

  FIG. 6D shows a case where the center of the third group lens L3 is moved by a distance d in the pitch direction due to the Lorentz force 60 generated by energizing the coil 28p (not shown). As described with reference to FIG. 6B, the rotational force 52 acts on the magnet 24p. On the other hand, the pull back force 51y acts on the yaw-side magnet 24y as described with reference to FIG. Due to the pullback force 51y, a rotational moment is applied to the shift member about an axis parallel to the optical axis. As a result, as shown in FIG. 6C, a counterclockwise roll motion is generated in the shift member. The shift member stops at a position where all of the rotational force, rotational moment, pullback force, Lorentz force, and the like are balanced. Therefore, according to the configuration of the present embodiment, compared with the conventional configuration, the rotational moment due to the pull-back force 51y is alleviated by the rotational force 52 of the pitch-side magnet 24p, so the roll operation of the shift member is reduced.

  FIG. 6E shows a case where the center of the third lens unit L3 is moved by a distance d in the direction opposite to that in FIG. As described with reference to FIG. 6B, the rotational force 52 acts on the magnet 24p. On the other hand, as in the case of FIG. 6D, a pulling back force 51y acts on the yaw-side magnet 24y. Due to the pullback force 51y, a rotational moment is applied to the shift member about an axis parallel to the optical axis. As a result, as shown in FIG. 6E, a clockwise roll operation occurs in the shift member. The shift member stops at a position where all of the rotational force, rotational moment, pullback force, Lorentz force, and the like are balanced. Therefore, according to the configuration of the present embodiment, compared with the conventional configuration, the rotational moment due to the pull-back force 51y is alleviated by the rotational force 52 of the pitch-side magnet 24p, so the roll operation of the shift member is reduced.

  Thus, in the movement of the movable group (shift member) in the pitch direction, the rotational moment due to the pull back force of the yaw side magnet and the rotational force of the pitch side magnet always act in opposite directions. Therefore, the roll operation of the shift member is reduced regardless of whether the pitch moves in the vertical direction. In the present embodiment, only the movement in the pitch direction has been described, but the roll operation is similarly reduced for the movement in the yaw direction. As described above, in this embodiment, the rotational force acting on the magnet by the movement of the shift member relieves the rotational moment due to the pulling force acting between the other magnet and the yoke, so that the roll operation of the shift member can be reduced. It is.

  Here, as shown in FIG. 6 (a), the width of the protrusion 30p of the yoke 29p in the drive direction (pitch direction) closer to the magnet 24y (yoke 29y) is A, and the side farther from the magnet 24y (yoke 29y). Let B be the width of the protrusion 30p in the driving direction. At this time, the relationship of A <B is established. That is, when viewed in the optical axis direction, the width of the protrusion 30p in the first direction (pitch direction) far from the yoke 23y is larger than the width near the yoke 23y. Similarly, when viewed in the optical axis direction, the width of the protrusion 30y in the second direction (yaw direction) far from the yoke 23p is larger than the width near the yoke 23p. Further, when the width in the driving direction of the magnet 24p is C, it is desirable that the relationship of B + 2d <C is established among the widths A, B, C and the distance d.

  In the present embodiment, the protruding portion 30p of the yoke 29p (the protruding portion 30y of the yoke 29y) has a trapezoidal shape (substantially trapezoidal shape) when viewed in the optical axis direction. The rotational motion of the shift member is reduced by using the rotational moment of the pulling force that acts between the magnet and the yoke generated in such a shape. However, in this embodiment, it is only necessary that the pulling-back force acting on the protruding portion of the yoke is asymmetric with respect to the axis parallel to the driving direction. For this reason, the shape of the yoke is not limited to a substantially trapezoid, and for example, each protrusion shown in FIG. 7 can be applied. FIG. 7 is a diagram showing another form of yoke (projection shape) in this embodiment. 7A is a stepped protrusion 30a, FIG. 7B is a protrusion 30b with three triangular corners, FIG. 7C is a flask-like protrusion 30c, and FIG. A substantially triangular protrusion 30d is shown. Each of the protrusions shown in FIGS. 7A to 7D is shaped so that the pitch side yoke 29p becomes wider in the direction away from the yaw side yoke 29y. With such a shape, the magnetic attraction force generated between the magnet 24p and the yoke 29p increases in the direction orthogonal to the drive direction as the distance from the yoke 29y on the yaw side increases. For this reason, it is possible to apply a reverse moment to the moment caused by the yoke 29y on the yaw side.

  Next, with reference to FIG. 8, the optical apparatus provided with the lens barrel in the present embodiment will be described. FIG. 8 is a configuration diagram of an optical apparatus (imaging device) in the present embodiment. In the optical device 120, an image of a subject formed on the CCD 113 (imaging device) through the lens is input to the camera signal processing circuit 101, and predetermined processing such as amplification and γ correction is performed. An output signal (video signal) from the camera signal processing circuit 101 passes through the AF gate 102 or the AE gate 103, and a contrast signal in a predetermined region is extracted. In particular, the contrast signal that has passed through the AF gate 102 generates one or a plurality of outputs related to the high frequency component by the AF circuit 104.

  The CPU 105 determines whether the exposure is optimal according to the signal level of the AE gate 103. When the exposure is not optimal, the CPU 105 controls the aperture shutter drive source 109 via the aperture shutter drive source 109 so that the shutter is driven at an optimal aperture value or shutter speed. In the autofocus operation, the CPU 105 controls the focus drive circuit 111 that is a focus drive source so that the output generated by the AF circuit 104 shows a peak. Further, the CPU 105 controls the aperture shutter drive source 109 so that the output of the aperture encoder 108 becomes the predetermined value by setting the average value of the signal output that has passed through the AE gate 103 to a predetermined value in order to obtain an appropriate exposure. Controls the aperture diameter of the aperture shutter.

  A focus origin sensor 106 using an encoder such as a photo interrupter detects an absolute reference position for detecting the absolute position of the focus lens group in the optical axis direction. A zoom origin sensor 107 using an encoder such as a photo interrupter detects an absolute reference position for detecting the absolute position of the zoom lens group in the optical axis direction. The CPU 105 drives the zoom drive source 110 by controlling the zoom drive circuit 112 based on information from the zoom origin sensor 107. The detection of the shake angle in the imaging device is performed by integrating the output of an angular velocity sensor such as a vibrating gyroscope fixed to the imaging device, for example. The outputs of the pitch angle detection sensor 114 and the yaw angle detection sensor 115 are processed by the CPU 105. The CPU 105 controls the pitch coil drive circuit 116 in accordance with the output from the pitch angle detection sensor 114, and controls energization to the coil 28p (not shown). Further, the CPU 105 controls the yaw coil drive circuit 117 in accordance with the output from the yaw angle detection sensor 115 and controls energization to the coil 28y (not shown).

  With the above control, the shift movement frame 22 (see FIG. 1) shifts in the plane orthogonal to the optical axis. The outputs of the pitch position detection sensor 118 and the yaw position detection sensor 119 are processed by the CPU 105. When the third lens group L3 (correction lens group) shifts, the passing light beam in the lens barrel is bent. For this reason, the third lens unit L3 is shifted and moved so that the passing light beam is bent by the bending amount to be canceled in the direction to cancel the change of the subject image on the CCD 113 that is originally caused by the shake of the imaging device. Accordingly, it is possible to perform so-called shake correction in which a subject image that is formed does not move on the CCD 113 even if the imaging apparatus is shaken. The CPU 105 is a signal corresponding to the difference between the shake signal of the imaging device obtained by the pitch angle detection sensor 114 and the yaw angle detection sensor 115 and the shift amount signal obtained from the pitch position detection sensor 118 and the yaw position detection sensor 119. (Difference signal) is calculated. Then, the CPU 105 performs amplification and phase compensation on the difference signal, and shifts the shift moving frame 22 using the pitch coil driving circuit 116 and the yaw coil driving circuit 117. By this control, the third lens unit L3 is positioned and controlled so that the difference signal becomes smaller, and is maintained at the target position.

  In the present embodiment, the case where the shift moving frame 22 is driven using a moving magnet type actuator has been described. However, the present invention is not limited to this. This embodiment can also be applied to a case where a so-called moving coil type actuator in which the coil 28 and the yoke 29 are arranged on the magnet base 18 side and the yoke 23 and the magnet 24 are arranged on the shift base 21 side is used.

  According to the present embodiment, it is possible to provide a shake correction device, a lens barrel, and an optical apparatus that reduce the rotation of the shift member in the plane orthogonal to the optical axis at a low cost.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

3 Shift unit (shake correction device)
24p, 24y Magnet 28p, 28y Coil 29p, 29y Yoke 30p, 30y Projection L3 Third lens group (correction lens group)

Claims (8)

A shift member holding the lens;
A first drive unit that moves the shift member in a first direction within a plane perpendicular to the optical axis with respect to the main body unit;
A second drive unit that moves the shift member in a second direction different from the first direction in a plane orthogonal to the optical axis with respect to the main body unit;
The first drive unit is configured by sequentially arranging a first magnet, a first coil, and a first yoke in the optical axis direction,
The second drive unit is configured by sequentially arranging a second magnet, a second coil, and a second yoke in the optical axis direction,
The first yoke has a first protrusion protruding in the optical axis direction and toward the first magnet,
The second yoke has a second protrusion protruding in the optical axis direction and toward the second magnet,
In the optical axis direction view,
The width of the first protrusion in the first direction on the side far from the second yoke is larger than the width on the side near the second yoke,
The shake correction apparatus according to claim 1, wherein a width of the second protrusion in the second direction on the side farther from the first yoke is larger than a width on the side closer to the first yoke.   The shake correction apparatus according to claim 1, wherein each of the first protrusion and the second protrusion has a trapezoidal shape when viewed in the optical axis direction.   The shake correction apparatus according to claim 1, wherein the first direction and the second direction are orthogonal to each other in a plane orthogonal to the optical axis. The first magnet and the second magnet are held by one of the shift member or the main body,
The said 1st coil, the said 1st yoke, the said 2nd coil, and the said 2nd yoke are hold | maintained at the other of the said shift member or the said main-body part, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The shake correction apparatus according to item 1.   A plurality of clamped members between the shift member and the main body due to the magnetic attractive forces acting between the first magnet and the first yoke and between the second magnet and the second magnet, respectively. The shake correction apparatus according to claim 1, further comprising a ball.   The shake correction apparatus according to claim 5, wherein the shift member shifts in the plane when the plurality of balls roll in a plane orthogonal to the optical axis.   A lens barrel comprising the shake correction device according to claim 1.   An optical apparatus comprising the lens barrel according to claim 7.