JP2014174270A - Image blur correction device, lens barrel, optical equipment, and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve optical performance when an optical element is moved by variably setting the curvature radius of a surface where the optical element for correcting an image blur is moved.SOLUTION: A lens barrel includes a lens moving mechanism supporting a lens 1041, to make it movable in an optical axis direction and an image blur correction device 110 moving a correction lens 111 along a predetermined surface, to correct the image blur. The image blur correction device 110 includes a movable part 112 holding the correction lens 111 and a driving part moving the movable part 112. A rolling ball 114 arranged between the movable part 112 and a fixed base plate 113 movably supports the movable part 112. A retainer 115 is rotatable around a point on an optical axis as a rotation center point and the curvature radius of the predetermined surface when the movable part 112 is moved is set. The retainer 115 is rotated according to the movement in the optical axis direction of the lens 1041, so that the movable part 112 can be moved along a plane or a spherical surface.

Description

  The present invention relates to an image shake correction apparatus mounted on an imaging apparatus such as a digital camera, an optical device such as a digital single lens reflex interchangeable lens, binoculars, and a telescope.

  Some lens barrels mounted on digital cameras and the like include an image blur correction device. The image shake correction apparatus drives an image shake correction unit that holds an optical member or an image sensor in two directions (yaw direction and pitch direction) in a plane orthogonal to the optical axis, thereby affecting the influence of camera shake that occurs during shooting. To ease.

  The image blur correction device disclosed in Patent Document 1 drives an image blur correction unit that holds a correction lens in two directions on a spherical surface with a predetermined point as a sphere, thereby moving the correction lens. Prevent degradation of optical performance.

JP 2008-134329 A

  The plurality of lens groups constituting the optical apparatus move by zooming operation or focus adjustment. Therefore, in order to optimize the optical performance when the correction lens is rotated, it is necessary to change the radius of curvature from the rotation center of the correction lens according to the position of the lens group. However, in the image blur correction device disclosed in Patent Document 1, the position of the sphere center around which the correction lens rotates is fixed, and the curvature radius of the spherical surface on which the correction lens moves is constant. Therefore, in the lens barrel using the image blur correction device disclosed in Patent Document 1, the optical performance when the correction lens is rotated in accordance with the movement of the optical system in the optical axis direction or the change in the number of components to be configured. Cannot be optimized.

  An object of the present invention is to improve the optical performance when the optical element is moved by variably setting the radius of curvature of the surface on which the image blur correcting optical element moves.

  In order to solve the above-described problems, an apparatus according to the present invention is an image shake correction apparatus that corrects image shake by moving a movable portion that holds an optical element in a direction orthogonal to an optical axis. Drive means for moving the part, and curvature radius setting means for setting the curvature radius of the surface on which the movable part moves by the drive means.

  According to the present invention, it is possible to improve the optical performance when the optical element is moved by variably setting the radius of curvature of the surface on which the image blur correcting optical element moves.

It is a disassembled perspective view of the lens barrel in 1st Embodiment of this invention. It is sectional drawing of the lens-barrel of FIG. 1 is an exploded perspective view of an image shake correction apparatus according to a first embodiment of the present invention. FIG. 4 is an exploded perspective view of the image shake correction apparatus of FIG. 3 viewed from the opposite direction on the optical axis. It is sectional drawing of an image blur correction apparatus when a retainer exists in a 1st position. It is a front view in the state of FIG. 5, and has shown only some components. FIG. 6 is a cross-sectional view of the image blur correction device when the retainer is in a second position. It is a front view in the state of FIG. 7, and shows only some components. It is a disassembled perspective view of the lens barrel in 2nd Embodiment of this invention. It is a front view of the image blur correction apparatus used in 2nd Embodiment of this invention, and shows only one part. It is a figure for demonstrating the positional relationship of a retainer and a cam cylinder. It is sectional drawing in the surface parallel to the optical axis of the image blur correction apparatus of 3rd Embodiment of this invention. It is sectional drawing in the surface parallel to the optical axis of the image blur correction apparatus of 4th Embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The image shake correction apparatus according to each embodiment can be mounted on an optical apparatus including an imaging apparatus such as a video camera, a digital camera, and a silver salt still camera, and an observation apparatus such as a binocular, a telescope, and a field scope. For example, each embodiment can be applied to an image blur correction optical system that forms an imaging optical system in an imaging apparatus. A unit that corrects image blur due to vibration such as camera shake using the image blur correction lens is controlled by a drive control unit.

[First Embodiment]
The lens barrel according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is an exploded perspective view showing components of the lens barrel 100. The lens barrel 100 includes a rectilinear barrel 101, a cam barrel 102, a fixed lens group 103, a movable lens group 104, and an image blur correction device 110. FIG. 2 is a cross-sectional view of the assembled lens barrel 100 taken along a plane parallel to its optical axis. FIG. 2A shows a state where the cam cylinder 102 is at the first angular position. FIG. 2B shows a state where the cam cylinder 102 is at the second angular position. In the following, the subject side in the optical axis direction is defined as the front side, the imaging element side in the optical axis direction is defined as the rear side, and the side perpendicular to the optical axis and approaching the optical axis (the radially inner side of the lens barrel) is defined as the inner side. Then, the positional relationship of each part will be described.
The rectilinear cylinder 101 is a substantially cylindrical member, and holds the fixed lens group 103 and the image blur correction device 110 on the inner periphery of the rectilinear cylinder 101. The rectilinear cylinder 101 pivotally supports the cam cylinder 102 at the outer periphery of the rectilinear cylinder 101 so as to be rotatable. The rectilinear cylinder 101 has a plurality of rectilinear grooves 1011 extending in the axial direction. The three rectilinear grooves 1011 are respectively fitted with the three cam followers 1043 included in the movable lens group 104. By this fitting, the rectilinear cylinder 101 supports the movable lens group 104 so as to be movable in the optical axis direction.

  The cam cylinder 102 is a cylindrical member, and is pivotally supported by the rectilinear cylinder 101 so as to be rotatable on the outside thereof. The cam cylinder 102 has a lens barrel cam groove 1021 and a curvature operation groove 1022. The lens barrel cam grooves 1021 are three grooves formed in a spiral shape, and are respectively fitted to the cam followers 1043 of the movable lens group 104. The curvature operation groove 1022 is formed at a position near the rear end of the cam cylinder 102, and details thereof will be described later.

The fixed lens group 103 includes a first lens group 1031 and a first lens frame 1032. The first lens frame 1032 holds the first lens group 1031 and is fixed to the rectilinear tube 101.
The movable lens group 104 includes a second lens group 1041, a second lens frame 1042, and a plurality of cam followers 1043. The second lens frame 1042 holds the first lens group 1041. Three cam followers 1043 are attached to the outer periphery of the second lens frame 1042, and engage with the rectilinear groove 1011 and the lens barrel cam groove 1021, respectively. The plurality of cam followers 1043 are guided to the intersections of the rectilinear grooves 1011 and the lens barrel cam grooves 1021. Therefore, as the cam cylinder 102 rotates, the movable lens group 104 can advance and retract in the optical axis direction along the direction of the rectilinear groove 1011.
As described above, in this embodiment, the linear movement cylinder 101, the cam cylinder 102, and the movable lens group 104 constitute a lens moving mechanism.

  The image blur correction apparatus 110 includes a correction lens 111 and a retainer 115 (see FIG. 2). The image blur correction device 110 supports the correction lens 111 so as to be rotatable to an arbitrary position on a spherical surface centered on a rotation center point on the optical axis (hereinafter referred to as a point O). In this specification, lens driving on a plane is regarded as a kind of driving on a spherical surface, and the rotation center point O in that case is set to a position at infinity from the correction lens 111. That is, a plane orthogonal to the optical axis is regarded as a spherical surface having an infinite curvature radius with respect to the rotation center point O.

  The image blur correction device 110 drives the correction lens 111 in accordance with a control command from a drive control unit (not shown). As a result, an image blur correction operation for moving the optical image that has passed through the imaging optical system is performed, and the stability of the image on the imaging surface can be ensured. The correction lens 111 can decenter an image formed by the imaging optical system, and constitutes an image blur correction optical system. In the present embodiment, a third lens group (correction lens) 111 is used as an optical element constituting the image blur correction optical system. However, the present invention is not limited to this, and it is possible to ensure the stability of the image on the imaging surface even when the imaging means such as a CCD (charge coupled device) sensor is driven with respect to the imaging optical system. In this case, the imaging means constitutes an image blur correction optical system.

  The retainer 115 is a guide member that is rotatably supported around a point on the optical axis. The distance between the correction lens 111 and the rotation center point O can be changed by rotating the retainer 115. In other words, the curvature radius of the spherical surface when the correction lens 111 moves on the spherical surface can be set or changed. The retainer 115 constitutes a curvature radius setting means by its movement. The retainer 115 has a protrusion 1152 (see FIG. 1). The protrusion 1152 is fitted with a curvature operation groove 1022 provided in the cam cylinder 102. Details of the retainer 115 will be described later.

  When the correction lens 111 moves from the center of the imaging optical system, the optical performance generally decreases. However, by performing an appropriate optical design, the performance deterioration can be suppressed to a negligible level. Further, when the correction lens 111 moves along the spherical surface, the optical performance can be further prevented from lowering by setting the radius of curvature of the spherical surface to an appropriate size. The imaging optical system used in the present embodiment has the most advantageous radius of curvature in terms of optical performance between the state shown in FIG. 2A and the state shown in FIG.

Next, the mechanism part of the lens barrel 100 will be described.
The first lens group 1031, the second lens group 1041, and the third lens group 1051 constitute an imaging optical system of the lens barrel 100. The light from the subject that has passed through the lens barrel 100 forms an image on the light receiving surface of the image sensor or the photosensitive surface of the photographic film. The lens barrel 100 operates the cam barrel 102 to adjust the distance in the optical axis direction between the lens groups in order to change the magnification of the subject image, adjust the focus, and adjust the aberration of the imaging optical system. When the cam cylinder 102 is at the first angular position as shown in FIG. 2A, for example, the imaging optical system is set to the telephoto side. When the cam cylinder 102 is at the second angular position as shown in FIG. 2B, for example, the imaging optical system is set to the wide angle side.

  The cam cylinder 102 is connected to the protrusion 1152 of the retainer 115 by a curvature operation groove 1022. For this reason, the radius of curvature of the surface on which the correction lens 111 can move is also changed with the movement of the lens group in the optical axis direction by the rotation of the cam cylinder 102. The image blur correction device 110 is set to a radius of curvature that minimizes the decrease in optical performance at each position. This is based on the curvature radius setting function by the movement of the retainer 115. That is, the lens group of the imaging optical system moves in the optical axis direction, and the curvature radius of the surface that determines the movement of the image blur correction optical system is changed according to the change in position. As a result, when the positional relationship of the image blur correction optical system changes due to a change in photographing magnification or focus adjustment, the radius of curvature of the surface on which the image blur correction optical system can move at each position is the most advantageous value in terms of optical performance. Can be set to

Next, the image blur correction device 110 will be described in detail with reference to FIGS.
First, components of the image blur correction device 110 will be described. FIG. 3 is an exploded perspective view of the image blur correction apparatus 110 when viewed from the front side. FIG. 4 is an exploded perspective view of the image blur correction device 110 viewed from the rear side. The image blur correction device 110 includes a movable unit 112 that holds a correction lens 111. A plurality of rolling balls 114 and a retainer 115 are disposed between the movable portion 112 and the fixed ground plate 113. The image blur correction device 110 further includes a plurality of biasing springs 116, a first driving unit 117, a second driving unit 118, and a lid 119. The first drive unit 117 includes a first magnet 1171 and a first coil 1172. The second drive unit 118 includes a second magnet 1181 and a second coil 1182. The first drive unit 117 and the second drive unit 118 generate Lorentz force by energizing the first coil 1172 and the second coil 1182 with a drive signal from a drive control unit (not shown).

  FIG. 5 is a cross-sectional view of the assembled image blur correction device 110 taken along a plane parallel to the optical axis. In this state, the retainer 115 is in the first position. FIG. 6 is a front view in the state of FIG. FIG. 7 is a cross-sectional view showing the assembled image blur correction device 110 taken along a plane parallel to the optical axis. In this state, the retainer 115 is in the second position. FIG. 8 is a front view in the state of FIG. 6 and 8, only the fixed ground plate 113, the rolling balls 114, and the retainer 115 are shown for convenience of explanation.

  The movable portion 112 is a movable member that holds the correction lens 111 in the central opening. The movable portion 112 includes a movable side ball support flat surface portion 1121, a movable side ball support spherical surface portion 1122 (see FIG. 4), and a movable side spring hook portion 1123. The movable side ball support plane part (hereinafter referred to as the movable side plane part) 1121 and the movable side ball support spherical part (hereinafter referred to as the movable side spherical part) 1122 constitute a movable side contact area that contacts the rolling ball 114. The movable-side contact area has a planar first area and a second area that forms a part of a spherical surface.

The movable side flat portion 1121 has a plane orthogonal to the optical axis, and is equally distributed at three locations around the correction lens 111. The movable side spherical surface portion 1122 is disposed on the outer peripheral side of the three movable side flat surface portions 1121. The contact surface with the rolling ball 114 forms a part of a spherical surface with the rotation center point O located on the optical axis as a centroid. The movable side spring hook 1123 holds one end of the biasing spring 116. The movable side spring hooks 1123 are equally arranged around the correction lens 111 at three locations around the optical axis.
The fixed ground plate 113 is formed in a substantially disk shape, and is fixed to a lens barrel that fixes another lens group (for example, a lens group constituting the imaging optical system). The fixed ground plate 113 has an opening in the center, and the movable portion 112 is disposed in the opening, thereby limiting the movement range of the movable portion 112. The fixed ground plate 113 has a fixed-side ball support flat surface portion 1131 and a fixed-side ball support spherical surface portion 1132 at three locations around the optical axis. The fixed-side ball support flat surface portion (hereinafter referred to as “fixed-side flat surface portion”) 1131 and the fixed-side ball support spherical surface portion (hereinafter referred to as “fixed-side spherical surface portion”) 1132 constitute a fixed-side contact region where the rolling ball 114 contacts. The fixed-side contact region has a planar first region and a second region having a part of a spherical surface.

The fixed side plane portion 1131 is equally divided into three portions so as to face the movable side plane portion 1121. The fixed-side spherical surface portion 1132 is disposed on the outer peripheral side of the three fixed-side flat surface portions 1131 so as to face the movable-side spherical surface portion 1122. In the fixed spherical surface portion 1132, the contact surface with the rolling ball 114 forms a part of a spherical surface with the rotation center point O located on the optical axis as a spherical center. Therefore, the fixed-side spherical portion 1132 is on a spherical surface that is concentric with the movable-side spherical portion 1122. Further, the radius of the fixed spherical surface portion 1132 is smaller than the radius of the movable spherical surface portion 1122 by the diameter of the rolling ball 114. The width in the direction around the optical axis of the fixed-side flat surface portion 1131 and the fixed-side spherical surface portion 1132 is larger than the length obtained by adding half the movable amount of the movable portion 112 to the diameter of the rolling ball 114. Therefore, the rolling balls 114 can be accommodated in the grooves of the fixed side flat surface portion 1131 and the fixed side spherical surface portion 1132.
The fixed ground plate 113 has a retainer support portion 1133 around the central opening, and rotatably supports the retainer 115. The fixed ground plate 113 has a fixed-side spring hook 1134 (see FIG. 4) on the bottom surface. Fixed side spring hooks 1134 for attaching one end of the urging spring 116 are equally arranged at three locations around the optical axis. The fixed ground plate 113 has a rotation restricting portion 1135 on the side surface portion. The rotation restricting portion 1135 is a notch provided in the outer peripheral portion of the fixed ground plate 113 and restricts the movable range of the retainer 115.

The rolling ball 114 is a movable support member that rolls and supports the movable portion 112 with respect to the fixed ground plate 113. The detailed function will be described later. In the present embodiment, three rolling balls 114 are used, but the number is not limited. Further, the movable support member is not limited to a spherical shape such as the rolling ball 114, and may be a dice-like member with good slidability.
The retainer 115 is formed in a substantially disc shape, and is supported by the retainer support portion 1133 so that the retainer 115 is pivotally supported with respect to the fixed base plate 113 between a first position and a second position described later. The retainer 115 has cam groove portions 1151 at three locations in the direction around the optical axis. The central axis of the cam groove 1151 is formed in a so-called Archimedean spiral, and the distance from the rotation center changes at a constant rate with respect to the rotation of the retainer 115. The width of the cam groove 1151 is larger than the length obtained by adding half the movable amount of the movable portion 112 to the diameter of the rolling ball 114. That is, the rolling ball 114 can be stored in the cam groove 1151.

  The retainer 115 has a protrusion 1152 protruding outward from the outer peripheral edge thereof. The protrusion 1152 is disposed in the notch of the rotation restricting portion 1135 of the fixed ground plate 113. Hereinafter, the position at which the protrusion 1152 contacts one end of the rotation restricting portion 1135 (the inner edge of the notch) is defined as the first position of the retainer 115. Further, the position where the protrusion 1152 contacts the other end of the rotation restricting portion 1135 is defined as the second position of the retainer 115. When viewed from the optical axis direction, the cam groove portion 1151 intersects the movable side plane portion 1121 and the fixed side plane portion 1131 at the first position. At this time, the cam cylinder 102 is at the first angular position shown in FIG. Further, in the second position, the cam groove 1151 intersects the movable side spherical portion 1122 and the fixed side spherical portion 1132. At this time, the cam cylinder 102 is at the second angular position shown in FIG.

  The three urging springs 116 are tension springs that generate an urging force proportional to the amount of deformation. One end of the biasing spring 116 is attached to the movable side spring hooking portion 1123, and the other end is attached to the fixed side spring hooking portion 1134. Thereby, an urging force is generated between the fixed ground plate 113 and the movable portion 112. With this urging force, the rolling ball 114 is sandwiched between the fixed ground plate 113 and the movable portion 112, and the rolling ball 114 maintains a contact state between the fixed ground plate 113 and the movable portion 112. In this embodiment, an elastic force is used as the biasing force. However, the biasing means is not limited to a spring, and biasing means that uses an electrostatic force or a magnetic force to apply a biasing force between the movable member and the fixed member. There may be.

  The first driving unit 117 generates a driving force that moves the movable unit 112 in a first direction orthogonal to the optical axis of the correction lens 111. In this embodiment, a voice coil motor using a first magnet 1171 and a first coil 1172 is used. The first magnet 1171 is configured integrally with the movable portion 112, and the surface facing the first coil 1172 is divided into two parts, which are magnetized to N and S poles, respectively. The first coil 1172 is disposed to face the magnetized surface of the first magnet 1171 and is fixed to a lid 119 that is a fixing member. When the first coil 1172 is energized, Lorentz force is generated by the action of the magnetic flux generated by the first magnet 1171, and the movable portion 112 is driven. The principle and type of the first drive unit 117 are not limited, and a known drive unit such as a stepping motor or an ultrasonic motor may be used.

The second driving unit 118 generates a driving force that moves the movable unit 112 in the second direction orthogonal to the optical axis direction of the correction lens 111 and the driving direction of the first driving unit 117. The configuration of the voice coil motor is the same as that of the first drive unit 117. The second drive unit 118 is arranged with a 90 ° rotational phase difference from the first drive unit 117, and a detailed description thereof is omitted.
The lid 119 is configured as a disk having a center hole and is a fixing member fixed to the fixed base plate 113. The movable part 112, the retainer 115, etc. are accommodated in the space formed with the fixed ground plate 113. Thereby, even when an impact force is applied to the image blur correction device 110 or when the posture difference changes, it is possible to prevent the internal components from falling off. The lid 119 holds the first coil 1172 and the second coil 1182 (see FIGS. 5 and 7).

Next, the operation of the image blur correction apparatus 110 will be described.
When the retainer 115 is in the first position, as shown in FIG. 6, the rolling ball 114 is disposed in a space surrounded by the cam groove portion 1151 and the fixed-side plane portion 1131. At this time, the rolling ball 114 is prevented from rolling to the fixed spherical surface portion 1132 by being guided by the cam groove portion 1151. Further, the rolling ball 114 is in contact with the movable side flat portion 1121 with respect to the movable portion 112. Since the movable portion 112 holds the rolling ball 114 between the movable base 112 and the fixed ground plate 113 by the biasing force of the biasing spring 116, the position of the movable portion 112 in the optical axis direction with respect to the fixed ground plate 113 is determined stably. . In this state, the movable portion 112 is supported so as to be movable in a plane orthogonal to the optical axis. By causing a predetermined current to flow through the coils of the first drive unit 117 and the second drive unit 118, the movable unit 112 can be moved to a target position in the plane. This plane is a plane parallel to the movable side plane portion 1121 and the fixed side plane portion 1131. The movement of the movable portion 112 corrects and stabilizes the image formed by the imaging optical system against vibrations such as camera shake. The position of the movable portion 112 in the rotational direction is a stable point determined by the urging forces of the three urging springs 116. Hereinafter, the surface on which the movable portion 112 is movably supported by the rolling ball 114 is referred to as a “movable surface”. With the retainer 115 in the first position, the movable surface is a flat surface.

  Next, a case where the retainer 115 is switched to the second position will be described. FIG. 8 shows a state in which the retainer 115 is rotated clockwise from the state of FIG. The rolling ball 114 moves into a space surrounded by the cam groove 1151 and the fixed spherical surface portion 1132. At this time, the rolling ball 114 is prevented from returning to the fixed flat surface portion 1131 by being guided by the cam groove portion 1151. The rolling ball 114 is in contact with the movable portion 112 at the movable spherical surface portion 1122. The movable portion 112 holds the rolling ball 114 between the movable portion 112 and the fixed ground plate 113 by the urging force of the urging spring 116.

  As described above, the radius of curvature of the movable-side spherical surface portion 1122 is equal to the length obtained by adding the diameter of the rolling ball 114 to the radius of curvature of the fixed-side spherical surface portion 1132. Therefore, regardless of the position of the rolling ball 114, the position of the movable portion 112 in the optical axis direction with respect to the fixed ground plate 113 is determined stably. In this state, the movable portion 112 is supported so as to be movable on the spherical surface around the rotation center point O located on the optical axis. That is, the movable surface in this case is a spherical surface. As the movable portion 112 is moved in the radial direction, the optical axis of the correction lens 111 is gradually inclined with respect to the original optical axis before the movement. By causing a predetermined current to flow through the coils of the first drive unit 117 and the second drive unit 118, the movable unit 112 can be moved to a target position on the spherical surface. By this movement, it is possible to correct and stabilize the image formed by the imaging optical system against vibrations such as camera shake. Note that the position of the movable portion 112 in the rotational direction is a stable point determined by the urging forces of the three urging springs 116.

  In the first embodiment, the movable surface of the movable portion 112 can be switched from a flat surface to a spherical surface or from a spherical surface to a flat surface by switching the rotational position of the retainer 115 by the rotation of the cam cylinder 102. Therefore, by rotating the retainer 115 in accordance with the change in the position of the imaging optical system in the optical axis direction, the optical system is optical in both the state shown in FIG. 2A and the state shown in FIG. Best performance.

[Modification]
Next, a modification of the first embodiment will be described.
(1) A modified form in which the support surface of the rolling ball is composed of a combination of a plurality of curved surfaces having different radii of curvature.
In the first embodiment, the movable side flat portion 1121 and the fixed side flat portion 1131 are each configured in a planar shape. These plane portions may be spherical portions, and the radius of curvature thereof may be different from that of the movable side spherical portion 1122 and the fixed side spherical portion 1132 and the radius of curvature. Thereby, the movable surface of the movable part 112 can be selected from a plurality of spherical surfaces having different curvature radii. The plane can be regarded as a spherical surface having an infinite curvature radius. Therefore, it can be said that the movable spherical surface portion 1122 and the movable flat surface portion 1121 which are movable contact regions are formed of spherical surfaces having different curvature radii. Similarly, it can be said that the fixed-side spherical portion 1132 and the fixed-side flat surface portion 1131 which are fixed-side contact regions are formed of spherical surfaces having different curvature radii.

(2) A modification in which opposing surfaces of the rolling ball support surfaces are formed of spherical surfaces having different center points (sphere centers).
In the first embodiment, the movable side flat surface portion 1121 and the movable side spherical surface portion 1122 are surfaces obtained by offsetting the fixed side flat surface portion 1131 and the fixed side spherical surface portion 1132 by the size of the diameter of the rolling ball 114, respectively. . That is, the movable-side plane portion 1121 is a spherical surface concentric with the fixed-side plane portion 1131 (in this case, the plane is regarded as having a spherical center at infinity). The movable spherical surface portion 1122 is a spherical surface concentric with the fixed spherical surface portion 1132. Thus, when the retainer 115 is in each of the first position and the second position, the distance from the respective rotation center point to the correction lens 111 is not changed without depending on the position of the rolling ball 114. The movable part 112 can be moved.
On the other hand, there is a configuration in which only one of the movable-side rolling ball support surface and the fixed-side ball support surface is formed with surfaces having different curvature radii. For example, this is a case where a ball support plane and a ball support spherical surface are formed on the movable part, and the ball support surfaces on the fixed ground plate facing each other are both flat. In this configuration, the position of the correction lens 111 in the optical axis direction can change depending on the position of the rolling ball 114 and the like. If the design allowing for this amount of variation is possible, even if only one of the opposing surfaces is formed with surfaces having different radii of curvature, the movable surface of the movable portion 112 can be moved by rotating the retainer 115. Can be switched. Thereby, since the shape of the other surface is simplified, the manufacturing becomes easy, which contributes to the improvement of the productivity of the image blur correction apparatus.

(3) A modification in which the drive control of the retainer is performed in accordance with the number of parts constituting the optical system.
In the first embodiment, the cam cylinder 102 rotates the retainer 115 according to the change in the position of the imaging optical system in the optical axis direction, so that the optical performance can be optimized when the correction lens is rotated. However, the distance from the correction lens to the rotation center point O for realizing the optimization of the optical performance does not always change only by the positional relationship of the optical system in the optical axis direction. For example, when another optical system such as an extender or a conversion lens is attached to the photographing optical system, the distance can be changed. The position for attaching such another optical system may be the front end, the rear end, or the middle of the lens barrel. In this case, a detection unit that detects the mounting position of another optical system is provided, and a drive control unit that drives the retainer 115 according to the position detection information is provided. That is, control is performed to set or change the distance from the rotation center point O to the correction optical system in accordance with a change in the number of parts constituting the optical system. By variably setting the radius of curvature of the spherical surface on which the correction lens for image blur correction moves, the optical when the correction lens is rotated according to the movement of the optical system in the optical axis direction or the change in the number of components Performance can be optimized.

[Second Embodiment]
Next, a lens barrel 200 according to a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, members having the same functions as those of the first embodiment are denoted by the same reference numerals as those used in the first embodiment, and detailed description thereof is omitted. Such a method of omission is the same in the embodiments described later.
First, members constituting the lens barrel of this embodiment will be described. FIG. 9 is an exploded perspective view illustrating a configuration example of the lens barrel 200. The lens barrel 200 includes a rectilinear barrel 101, a cam barrel 202, a fixed lens group 103, a movable lens group 104, and an image blur correction device 210.
The cam cylinder 202 has a plurality of cam grooves 2021, a curvature operation groove 2022, and an elastic deformation portion 2023. The curvature operation groove 2022 and the elastic deformation portion 2023 are formed near the rear end of the cam cylinder 202. The curvature operation groove 2022 is fitted with a protrusion 2152 of a retainer 215 provided in the image blur correction device 210. The curvature operating groove 2022 and the cylindrical portion of the cam barrel 202 are connected by an elastic deformation portion 2023.

Next, the image blur correction apparatus 210 will be described with reference to FIG. FIG. 10 is a front view when the retainer 215 is in the first position. The image blur correction device 210 includes a correction lens 111, a movable portion 112, a fixed base plate 213, a rolling ball 114 (in the cam groove portion 2151), a retainer 215, a biasing spring 116, a first drive portion 117, and a second drive portion. 118 and a lid 119. For convenience of explanation, only the fixed base plate 213, the rolling balls 114, and the retainer 215 are shown.
The fixed ground plate 213 has both ends of the rotation restricting portion 2135 magnetized to an N pole and an S pole, respectively, and is otherwise the same as the fixed ground plate 113 described in the first embodiment. The retainer 215 is different from the protrusion 1152 in that the protrusion 2152 is formed of a ferromagnetic material such as iron.

  A magnetic attractive force can be applied between the protrusion 2152 and the rotation restricting portion 2135. When the retainer 215 is in the first position or the second position, the magnetic potential energy of the retainer 215 can be relatively reduced. That is, in a state where the rolling ball 114 cannot move along the boundaries between the plurality of ball support surface portions, the potential energy of the retainer 215 is smaller than in a state where the rolling balls 114 can move along these boundaries. As a result, a stable position is obtained when the retainer is in the first position and the second position. The boundaries between the plurality of ball support surface portions are the boundary between the movable side flat surface portion 1121 and the movable side spherical surface portion 1122 and the boundary between the fixed side flat surface portion 1131 and the fixed side spherical surface portion 1132.

  When the movable part 112 is driven in a state where the retainer 215 is positioned between the first position and the second position, the rolling ball 114 gets over the boundary between the ball support plane part and the ball support spherical part, There is a possibility that the operation of the movable portion 112 becomes unstable. That is, the selection of whether the movable surface of the movable portion 112 is a spherical surface or a flat surface depends on the position of the rolling ball 114. Since the position of the rolling ball 114 can be easily changed by impact or the like, reproducible driving cannot be performed. By adopting the configuration of this embodiment, the frequency of occurrence of such a phenomenon can be reduced. Note that the means for maintaining the retainer 215 in a stable state at the first position and the second position is not limited to a method using magnetic energy, and the same applies to a means using elastic force or electrostatic force. The effect can be realized. In addition, even when each ball support surface is divided into three or more regions having different radii of curvature, the potential energy when the rolling ball 114 can move between the boundaries of each region is the same as when the boundary between the regions cannot be moved. What is necessary is just to make it higher than potential energy. Thereby, the same effect is acquired.

In the image blur correction device 210, the relationship between the rotation angle of the cam barrel 202 and the rotation angle of the retainer 215 has a so-called hysteresis characteristic. This characteristic will be described with reference to FIG.
FIG. 11A is a schematic diagram for explaining the mechanism of the cam cylinder 202 and the retainer 215. The rotation angle of the cam cylinder 202 is represented by X, and the rotation angle of the retainer 215 is represented by Y. A curve 2153 represents the potential energy of the retainer 215. The potential energy decreases as it goes downward in FIG. 11A, and the retainer 215 becomes stable. A region Z indicates a region where the rolling ball 114 can move on the boundary between the movable side flat surface portion 1121 and the movable side spherical surface portion 1122 and on the boundary between the fixed side flat surface portion 1131 and the fixed side spherical surface portion 1132.
In the state shown in FIG. 11A, even if the cam cylinder 202 is moved by a minute amount in the positive direction (right direction), the retainer 215 is moved by the magnetic attraction force acting between the protrusion 2152 and the rotation restricting portion 2135. Do not move. When the cam cylinder 202 is further moved and the elastic energy stored in the elastic deformation portion 2023 exceeds the potential energy when the retainer 215 is in the first position, the retainer 215 moves rapidly to the second position. At this time, the retainer 215 crosses the region Z between the first position and the second position. This can be realized by designing the potential energy distribution of the retainer 215 and the characteristics of the elastic deformation portion 2023 in an appropriate relationship.

When the retainer 215 is moved from the second position to the first position, the operation is opposite to that described above, and the retainer 215 is not stabilized in the region Z. FIG. 11B is a graph showing the relationship between X and Y. The horizontal axis represents the rotation angle X of the cam cylinder 202, and the vertical axis represents the rotation angle Y of the retainer 215. It can be seen that the movement path from the first position to the second position is different from the movement path from the second position to the first position, and exhibits hysteresis characteristics.
In the second embodiment, it can be avoided that the rolling ball 114 gets over the boundary between the flat surface portion and the spherical surface portion and becomes unstable regardless of the rotation position of the cam cylinder 202. As a result, the operation of the movable part 112 is stabilized.

  In the second embodiment, the rotation angle of the cam cylinder 202 and the lens position in the optical axis direction of the imaging optical system are equivalent. The relationship between the rotation angle of the cam cylinder 202 and the rotation angle of the retainer 215 has hysteresis, and the relationship between the lens position in the optical axis direction of the imaging optical system and the rotation angle of the retainer 215 has hysteresis. . In order to give hysteresis to the relationship between the rotation angle of the cam cylinder 202 and the rotation angle of the retainer 215, for example, control means for detecting the rotation angle of the cam cylinder 202 with a position sensor and controlling the angle of the retainer 215 with an actuator. May be taken. By using a hysteresis circuit for the control means, the same effect as described above can be obtained using an electrical circuit.

[Third Embodiment]
Next, a lens barrel according to a third embodiment of the present invention will be described with reference to FIG. The lens barrel according to the third embodiment is different from that of the first embodiment in the configuration of the image blur correction device 310. The image blur correction device 310 includes a correction lens 111, a movable portion 312, a fixed base plate 313, a rolling ball 114, a retainer 115, an urging spring 116, a first drive portion 117, a second drive portion 118, and a lid 119. .

FIG. 12 is a cross-sectional view of the assembled image blur correction device 310 taken along a plane parallel to the optical axis. At this time, the retainer 115 is in the first position. In this embodiment, the stepless ball support surface portion in which the curvature radius continuously changes is used instead of dividing the ball support surface portions on the movable side and the fixed side into a plurality of regions having different curvature radii. .
The movable part 312 has a movable ball support surface part 3121. The cross-sectional shape in the radial direction of the movable-side ball support surface portion 3121 (on the side facing the fixed ground plate 313) is formed by a curve in which the radius of curvature continuously changes, for example, a hyperbola or a parabola. In this embodiment, a curve is used in which the radius of curvature decreases as the radial distance increases, and the movable-side ball support surface portion 3121 is formed by a rotating surface obtained by rotating the curve around the optical axis.

The fixed ground plate 313 has a fixed-side ball support surface portion 3131. The cross-sectional shape in the radial direction of the fixed-side ball support surface portion 3131 (the surface facing the movable portion 312) is formed by a curve whose curvature radius changes continuously. In the present embodiment, the fixed-side ball support surface portion 3131 is formed by a curved surface formed by offsetting the curved surface forming the movable-side ball support surface portion 3121 by the diameter of the rolling ball 114.
By changing the angular position of the retainer 115, the contact point between the rolling ball 114, the movable side ball support surface portion 3121 and the fixed side ball support surface portion 3131 can be selected. When the contact point is moved to the outer peripheral side, the radius of curvature of the movable surface of the movable portion 312 can be reduced. Conversely, when the contact point is moved to the inner peripheral side, the radius of curvature of the movable surface of the movable portion 312 can be increased. On the other hand, when the movable area of the movable part 312 is increased, the radius of curvature when the movable part 312 moves changes between the center of the movable range and the vicinity of the boundary. When the amount of change in the radius of curvature can be ignored or when the design can be made in anticipation of the amount of change, the radius of curvature of the movable surface can be continuously changed by continuously changing the position of the retainer 115. Can do.

In the third embodiment, by using the image blur correction device 310, the radius of curvature of the movable surface of the image blur correction optical system is continuously changed according to the position of the cam cylinder, that is, the lens position of the imaging optical system. be able to. Thereby, the optical performance can be optimized according to each position with respect to the continuous position change in the optical axis direction of the optical system.
In the third embodiment, the configuration in which the movable portion 312 is supported by rolling with the rolling ball 114 that is a movable support member is exemplified. Thereby, since the sliding friction which generate | occur | produces in the movable part 312 can be made small, highly accurate positioning is realizable. As a modification, a configuration in which the rolling ball 114 is fitted to the cam groove portion 1151 and the support surface portion on the fixed side may be employed. In that case, the movable part 312 is slidably supported, not supported by rolling. Although sliding friction occurs, when the position of the retainer 115 is determined, the position of the rolling ball 114 is uniquely determined. Thereby, the dispersion | variation in the curvature radius of the movable surface resulting from the position of the rolling ball 114 can be made small.

[Fourth Embodiment]
Next, a lens barrel according to a fourth embodiment of the present invention will be described. FIG. 13 is a diagram illustrating a main part of the image blur correction device 410. Hereinafter, a configuration example of the image blur correction device 410 that is different from the above embodiment will be described in detail.
In the present embodiment, the position sensor 405 detects the rotational position of the cam cylinder 102 relative to the rectilinear cylinder 101 and converts it into an electrical signal. The detection signal is sent to the drive control unit 406. When the radius of curvature of the movable surface is changed depending on whether or not the extender or conversion lens is attached, the position sensor 405 is not the rotational position of the cam cylinder 102, but the change of the optical components constituting the optical system, Detect changes in the number of parts.

The image blur correction device 410 includes a correction lens 111, a movable portion 412, a fixed ground plate 413, an urging spring 116, a first coil 1172, a second coil 1182, and a lid 119. FIG. 13A is a cross-sectional view taken along a plane parallel to the optical axis when the radius of curvature of the movable surface of the correction lens 111 is set to R1. FIG. 13B is a cross-sectional view taken along a plane parallel to the optical axis when the radius of curvature of the movable surface of the correction lens 111 is set to R2.
The movable portion 412 holds the correction lens 111 and is supported so as to be movable with respect to the fixed base plate 413 via the contact portion 4121. The fixed ground plate 413 includes a deformation contact surface portion 4131 and a contact surface actuator 4132. Since the deformed contact surface portion 4131 comes into contact with the contact portion 4121, it has an appropriate surface hardness and strength. The contact surface actuator 4132 deforms the deformed contact surface portion 4131 based on the command value from the drive control unit 406. The deformable contact surface portion 4131 has an appropriate thickness and physical property value, and is elastically deformed into a spherical surface having a predetermined radius of curvature by the contact surface actuator 4132. As the contact surface actuator 4132, for example, a stepping motor using a piezoelectric element or a lead screw can be used. Further, a configuration in which the deforming contact surface portion and the contact surface actuator are integrated by using a bimorph actuator using a piezoelectric element or an artificial muscle actuator may be used.

Next, the operation of the image blur correction device 410 will be described.
When the position of the imaging optical system in the optical axis direction is changed by the rotation of the cam cylinder 102, the position sensor 405 detects the rotational position of the cam cylinder 102 relative to the rectilinear cylinder 101. The drive control unit 406 drives the contact surface actuator 4132 by a predetermined amount according to the detection position. As a result, the deformed contact surface portion 4131 is deformed so as to have an appropriate curvature radius. The movable part 412 is supported so as to be movable according to the shape of the deformation contact surface part 4131. As a result, the radius of curvature of the movable surface of the correction lens 111 can be set to a predetermined value.
FIG. 13A shows a state when the imaging optical system is set to the wide angle side, for example, and the radius of curvature of the movable surface is set to R1. FIG. 13B shows a state when the imaging optical system is set to the telephoto side, for example, and the radius of curvature of the movable surface is set to R2. By setting the values of R1 and R2 to appropriate values, the optical performance when the correction lens 111 is moved can be optimized.

In addition, you may arrange | position to a movable part about not only the said structure but a deformation | transformation contact surface part and a contact surface actuator. Further, as in the above embodiment, a rolling member (such as a ball or a cylindrical member) may be disposed between the movable member and the fixed member. As long as the curvature of the movable surface of the image blur correction optical system can be changed, any means for realizing it can be used.
In the fourth embodiment, a curvature radius setting unit is configured by the position sensor 405, the drive control unit 406, and the contact surface actuator 4132. Using the contact surface actuator 4132, the deformed contact surface portion 4131 can be set to have an arbitrary radius of curvature. In addition, a mechanism unit (a transmission mechanism using a cam, a gear, or the like) that deforms the deformable contact surface portion 4131 to a predetermined radius of curvature according to the positional relationship of the optical system in the optical axis direction may be used. In this case, the transmission mechanism constitutes a curvature radius setting unit.
The present invention is not limited to those exemplified in the above embodiments, and materials, shapes, dimensions, forms, numbers, arrangement locations, and the like can be appropriately changed without departing from the scope of the present invention. .

DESCRIPTION OF SYMBOLS 102 Cam cylinder 104 Movable lens group 110 Image shake correction apparatus 111 Correction lens 112 Movable part 1121,1122 Movable side contact area 113 Fixed ground plate 1131,1132 Fixed side contact area 114 Rolling ball (movable support member)
115 Retainer (guide member)

Claims (15)

An image blur correction apparatus that corrects image blur by moving a movable portion that holds an optical element in a direction perpendicular to the optical axis,
Drive means for moving the movable part;
An image blur correction apparatus comprising: a curvature radius setting unit that sets a curvature radius of a surface on which the movable unit moves by the driving unit. A guide member that is rotatable about a point on the optical axis as a rotation center point, and that constitutes the curvature radius setting means;
A fixed member that has a fixed-side contact region facing the movable-side contact region of the movable part and supports the guide member;
A movable support member that supports the movable part in a state where the movable part can be moved in contact with the movable side contact area of the movable part and the fixed side contact area of the fixed member;
An urging means for generating an urging force for holding the movable support member between the movable portion and the fixed member;
2. The curvature radius is set by changing the position where the guide member rotates about an axis and the movable support member contacts the movable contact area and the fixed contact area. The image blur correction device according to 1. The movable-side contact area and the fixed-side contact area each have a plurality of areas having a shape that forms a part of a spherical surface with different curvature radii,
The image blur correction apparatus according to claim 2, wherein the guide member rotates around an optical axis, and an area in contact with the movable support member is selected from the plurality of areas. The movable-side contact region and the fixed-side contact region each have a planar first region and a second region that forms a part of a spherical surface,
The image blur correction apparatus according to claim 2, wherein the guide member rotates around an optical axis and selects the first region or the second region in contact with the movable support member.   The image blur correction apparatus according to claim 2, wherein the movable contact area or the fixed contact area has a curved area in which a radius of curvature continuously changes.   The image blur correction device according to claim 1, wherein the curvature radius setting unit includes a deformation contact surface portion that contacts the movable portion, and an actuator or a mechanism portion that sets a curvature radius of the deformation contact surface portion. The driving means comprises a coil and a magnet;
The image blur correction apparatus according to claim 1, wherein the coil or the magnet is fixed to the movable portion. An image blur correction apparatus according to any one of claims 1 to 7,
A lens barrel having a lens moving mechanism for supporting the lens so as to be movable in the optical axis direction;
A lens barrel in which, when the lens moves in the optical axis direction, a curvature radius setting unit of the image blur correction apparatus sets the curvature radius. An image blur correction device according to any one of claims 2 to 5,
A lens barrel having a lens moving mechanism for supporting the lens so as to be movable in the optical axis direction;
The lens barrel includes a cam barrel that moves the lens in the optical axis direction and rotates the guide member. A detecting means for detecting a change in an optical component constituting the optical system;
The lens barrel according to claim 8 or 9, wherein the curvature radius setting means sets the curvature radius in accordance with the optical component detected by the detection means.   The lens barrel according to claim 9, further comprising a control unit that imparts hysteresis to a relationship between a position of the lens in the optical axis direction and a position of the guide member. The movable-side contact region and the fixed-side contact region that are in contact with the movable support member each have a plurality of regions with different curvature radii,
The control means is configured such that the potential energy of the guide member when the movable support member can pass through the boundaries of the plurality of regions is higher than the potential energy when the movable support member cannot pass through the boundaries of the plurality of regions. The lens barrel according to claim 11, wherein the lens barrel is set. An image blur correction device according to claim 6;
A lens barrel having a lens moving mechanism for supporting the lens so as to be movable in the optical axis direction;
When the lens moves in the optical axis direction, the curvature radius setting means of the image blur correction device detects the position of the lens or the number of parts constituting the optical system and drives the actuator or mechanism unit. A lens barrel characterized by setting the radius of curvature.   An optical apparatus comprising the lens barrel according to claim 1. An image pickup apparatus comprising the lens barrel according to claim 1.

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