JP2007171299A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel whose up-sizing is prevented or reduced by arranging a VCM (voice coil motor) of an antivibration lens utilizing a space of the VCM for driving a focusing lens even when the VCM is up-sized for raising thrust of the VCM which drives the antivibration lens. <P>SOLUTION: In the lens barrel 10, a VCM 72 for driving the antivibration lens 28 and a VCM 104 for driving the focusing lens 32 are arranged. The VCMs 72, 104 are arranged at positions where they are not overlapped by being viewed from the subject side in the direction of an optical axis O and are arranged at positions where portions are overlapped regarding the direction of the optical axis O by being viewed from the side direction of the optical axis O. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens barrel, and more particularly to a lens barrel including an image stabilizing lens for correcting image blur and an actuator for the same.

  A consumer video camera equipped with an image blur correction device is used. As an image blur correction apparatus, an optical type and an electronic type are known, and in recent years, an optical type is used in many products. In the case of the optical type, for example, an anti-vibration lens that is movable in the vertical and horizontal directions within a plane orthogonal to the optical axis is arranged in the photographing optical system, and the anti-vibration lens is an actuator according to the vibration generated in the camera. Image blur is corrected by moving vertically and horizontally.

  Patent Document 1 discloses a video camera equipped with such an image blur correction device. According to this, the anti-vibration lens is driven by a magnetic actuator, and the magnetic actuator is attached to the holding frame of the anti-vibration lens and is a flat type wound around a direction parallel to the optical axis. And a magnetic circuit that generates a magnetic field in a direction parallel to the axis of the coil (a direction parallel to the optical axis) at the position of the coil. By passing a current through the coil, a thrust in a direction orthogonal to the optical axis is applied to the holding frame by the action of the magnetic field generated by the coil and the magnetic field of the magnetic circuit, and the vibration-proof lens moves in the direction orthogonal to the optical axis.

On the other hand, the magnetic actuator as in Patent Document 1 has a drawback in that the thrust is insufficient when the vibration-proof lens is relatively large, and the response related to the image blur correction operation of the vibration-proof lens with respect to vibration is delayed. Therefore, it is preferable to use a voice coil motor (VCM) as a similar magnetic actuator. When driving a vibration-proof lens with a VCM, for example, a coil wound around a direction orthogonal to the optical axis is attached to a holding frame of the vibration-proof lens, and the position of the coil is orthogonal to the axis of the coil. A magnetic field in the direction (parallel to the optical axis) is generated by the magnetic circuit. The magnetic circuit is composed of a magnet (permanent magnet) and a U-shaped yoke, and the permanent magnet is fixed to one of the opposing surfaces inside the yoke. Thereby, a magnetic field is formed in the space between the other surface of the yoke and the permanent magnet. And then. A part of the coil of the holding frame is inserted and disposed in the gap. When a current is passed through the coil, a thrust in a direction perpendicular to the optical axis is applied to the holding frame by the action of the magnetic field and the current (Fleming's left-hand rule), and the vibration-proof lens moves.
JP 2000-227614 A

  However, even when a VCM is used as an actuator for driving the vibration-proof lens, the VCM becomes large in order to increase the thrust. Therefore, the length of the lens barrel is increased, which increases the size of the lens barrel, which is an adverse effect when the camera is downsized.

  The present invention has been made in view of such circumstances, and a lens capable of preventing or reducing the enlargement of the lens barrel caused by increasing the thrust of the VCM for driving the image stabilizing lens for image blur correction. An object is to provide a lens barrel.

  In order to achieve the above object, a lens barrel according to claim 1 is provided with an image stabilization lens for image blur correction supported in a direction perpendicular to the optical axis in the lens barrel body, and the lens barrel. A focus adjustment focus lens that is supported in the body so as to be movable in the optical axis direction, and a first voice that generates a thrust force for moving the image stabilization lens in a first direction orthogonal to the optical axis. A coil motor, a second voice coil motor that generates a thrust for moving the vibration-proof lens in a second direction that is orthogonal to the optical axis and orthogonal to the first direction, and A lens barrel including a third voice coil motor for generating a thrust for moving the focus lens in the optical axis direction, wherein the first to third voice coil motors are viewed from the optical axis direction. Arranged around the optical axis so as not to overlap, and arranged such that a part or the whole of the first and second voice coil motors overlaps with the third voice coil motor as viewed from the lateral direction of the optical axis. It is characterized by that.

  According to the present invention, even if the voice coil motor (VCM) for driving the anti-vibration lens is enlarged, the space for arranging the VCM for driving the focus lens can be used. Even if the VCM is increased in size in order to increase the thrust, it is possible to avoid the problem that the total length of the lens barrel is increased, and it is possible to prevent or reduce the increase in the size of the lens barrel.

  The lens barrel according to claim 2 is the lens barrel according to claim 1, wherein the first and second voice coil motors are arranged so that two yokes formed in a U-shape are adjacent to each other. The magnetic circuit is provided. According to the present invention, there is shown an aspect in which two yokes constituting a magnetic circuit are arranged adjacent to each other to increase the thrust of the VCM. In such a case, the VCM is enlarged, but the focus as in claim 1 By utilizing the arrangement space of the VCM of the lens, it is possible to prevent or reduce the enlargement of the lens barrel.

  According to a third aspect of the present invention, in the lens barrel according to the first or second aspect, the first and second voice coil motors are orthogonal to each other about the optical axis as viewed from the optical axis direction. It is characterized by being arranged in the direction. The present invention shows an arrangement mode of two VCMs of an anti-vibration lens.

  According to a fourth aspect of the present invention, in the lens barrel according to the first, second, or third aspect, the third voice coil motor includes two voice coil motors. The present invention shows an embodiment of a VCM for driving a focus lens.

  According to a fifth aspect of the present invention, in the lens barrel according to the first, second, third, or fourth aspect, the two voice coil motors constituting the third voice coil motor are each in the optical axis direction. From the viewpoint of the optical axis, the first and second voice coil motors are arranged symmetrically about the optical axis. The present invention shows an arrangement mode of two VCMs for driving the focus lens. According to this, the two VCMs of the anti-vibration lens and the two VCMs of the focus lens are arranged around the optical axis when viewed from the optical axis direction. They are arranged at substantially equal intervals.

  The lens barrel according to claim 6 is the lens barrel according to claim 1, 2, 3, 4, or 5, wherein the anti-vibration lens is disposed in front of the focus lens. It is said. The present invention shows an aspect in which, for example, in a lens barrel constituting a rear focus type photographing lens, an anti-vibration lens is arranged in front of the focus lens (object side).

  According to the lens barrel of the present invention, it is possible to prevent or reduce the increase in the size of the lens barrel due to the increase in the size of the VCM for driving the vibration-proof lens.

  The best mode for carrying out a lens barrel according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a lens barrel in a rear focus type variable focal length photographing lens used in, for example, a high-end video camera for consumer use, an ENG camera for television broadcasting, a surveillance camera, and the like to which the present invention is applied. It is side surface sectional drawing. In the figure, a lens barrel used in a lens-fixed camera is shown, and a color separation prism or the like mounted on the camera body in the interchangeable-lens camera is provided at the rear end of the lens barrel 10. The optical block is integrally attached.

  In FIG. 1, a fixed barrel (lens barrel body) of the lens barrel 10 is constituted by a front fixed barrel 14, a middle fixed barrel 16, and a rear fixed barrel 18 that are formed in a cylindrical shape and are sequentially connected. Each member constituting the lens barrel 10 is supported by the fixed cylinders 14, 16, and 18.

  On the optical axis O of the lens barrel 10, as an optical system for forming an image of a subject, a fixed lens (group) 20, a zoom (magnification) lens (group) 22, a diaphragm 24, and a fixed lens are sequentially arranged from the objective side. A (group) 26, an anti-vibration lens (group) 28, a fixed lens (group) 30, a focus lens (group) 32, a fixed lens (group) 34, and the like are arranged.

  The zoom lens 22 changes the zoom magnification (focal length) of the optical system, and is disposed inside the middle fixed cylinder 16 so as to be movable in the optical axis direction while being held by the holding frame 40. A flange portion 42 is formed on the holding frame 40 of the zoom lens 22, and is connected to the moving cylinder 44 via the flange portion 42. An intermediate cylinder 46 is fixed to the inner peripheral part of the middle fixed cylinder 16, and a rotary cylinder 48 is rotatably held on the inner peripheral part of the intermediate cylinder 46, and the movable cylinder 44 has an inner periphery of the rotary cylinder 48. Held in the department.

  Further, a rectilinear groove 46 A in the optical axis direction is formed on the inner peripheral surface of the intermediate cylinder 46, and a cam groove (cam-shaped hole) 48 A is formed in the rotating cylinder 48 and is fixed to the moving cylinder 44. The cam pin 50 is inserted into the cam groove 48A of the rotary cylinder 48 and engaged with the rectilinear groove 46A of the intermediate cylinder 46. As a result, the movable cylinder 44 moves straight in the direction of the optical axis O in a state where the rotation is restricted, and is held at a position where the cam pin 50 is engaged with the cam groove 48A. When the rotating cylinder 48 rotates, the intersection position of the cam groove 48A of the rotating cylinder 48 and the rectilinear groove 46A of the intermediate cylinder 46 changes to a position corresponding to the cam shape, and the moving cylinder is moved by the movement of the cam pin 50 to the intersection position. 44 moves forward and backward in the direction of the optical axis O.

  On the other hand, a zoom ring 52 is rotatably disposed on the outer peripheral portion of the middle fixed cylinder 16, and a rod-like connecting shaft 54 is attached radially inward of the inner peripheral surface of the zoom ring 52. The connecting shaft 54 is connected to the rotating cylinder 48 through a circumferential long hole formed in the middle fixed cylinder 16 and the intermediate cylinder 46. As a result, when the zoom ring 52 is rotated, the rotary cylinder 48 is rotated in conjunction therewith. When the rotating cylinder 48 rotates, the moving cylinder 44 moves forward and backward as described above, and the zoom lens 22 moves in the optical axis direction in conjunction with the moving cylinder 44. Accordingly, the zoom magnification is changed by rotating the zoom ring 52.

  The aperture 24 is configured to be opened and closed by aperture blades 64 disposed between the base plate 60 and the cam plate 62. An iris ring 66 is rotatably disposed between the middle fixed cylinder 16 and the rear fixed cylinder 18, and the iris ring 66 and the cam plate 62 are connected by a connecting shaft 68. Thereby, the iris 24 is opened and closed by the turning operation of the iris ring 66.

  The anti-vibration lens 28 is arranged to correct (prevent) image blur due to vibration generated in the lens barrel 10, and is moved in the vertical direction and the horizontal direction within a plane orthogonal to the optical axis by a predetermined support mechanism. Supported as possible. The anti-vibration lens 28 is held by a holding frame 70, and a voice coil motor (hereinafter referred to as VCM) 72 for driving the anti-vibration lens 28 in the vertical direction is connected to the lower side of the holding frame 70. ing.

  FIG. 2 is a schematic front view of the vibration-proof lens 28 when viewed from the subject side in the optical axis O direction. A VCM 72 is disposed below the holding frame 70 of the vibration-proof lens 28. When the anti-vibration lens 28 is displaced in the vertical direction by the VCM 72, the image forming position of the image finally formed by the photographing lens is also displaced in the vertical direction corresponding to the displacement. Accordingly, when the lens barrel 10 vibrates in the vertical direction, the image blur in the vertical direction is prevented by displacing the vibration-proof lens 28 in the vertical direction so as to cancel the image blur due to the vibration. ing. Similarly, as shown in FIG. 2, a VCM 74 having the same structure as the VCM 72 is connected to the holding frame 70 on the right side when viewed from the front side (optical axis direction subject side). . When the anti-vibration lens 28 vibrates in the left-right direction, the image blur in the left-right direction is prevented by displacing the anti-vibration lens 28 in the left-right direction by the VCM 74 so as to cancel the image shake due to the vibration. ing.

  Here, the structure of the VCM 72 will be described. As shown in FIG. 3, the VCM 72 is configured by arranging a coil 82 wound around a coil frame 80 in a magnetic circuit 84. The coil frame 80 is formed of a coil winding portion 80A in which a hollow portion 80C is formed and a connecting portion 80B. A coil 82 is wound around the outer periphery of the coil winding portion 80A, and an air-core coil is a coil. It is arranged on the frame 80.

  On the other hand, the magnetic circuit 84 includes two yokes 86 and 88 formed in two U-shapes, and these two yokes 86 and 88 are disposed adjacent to each other and installed in the rear fixed cylinder 18. Yes. Of the parallel portions 86A, 86B, 88A, 88B formed in parallel to the yokes 86, 88, plate-like magnets (permanent magnets) 90, 92 are fixed to the inner surfaces of the parallel portion 86A and the parallel portion 88A, respectively. Yes.

  As a result, a magnetic field is generated in the gaps 86C and 88C inside the yokes 86 and 88, respectively. For example, the exposed surface side of the magnet 90 exposed in the gap 86 </ b> C of the yoke 86 is the south pole, and at this time, the inner surface of the parallel portion 86 </ b> B that faces the exposed surface of the magnet 90 is the north pole. In the gap 86C, a magnetic field is generated in a direction from the inner surface of the parallel portion 86B to the exposed surface of the magnet 90.

  Similarly, the exposed surface side of the magnet 92 exposed in the gap 88C of the yoke 88 is the S pole, and the inner surface of the parallel portion 88B that faces the exposed surface of the magnet 92 is the N pole. In 88C, a magnetic field is generated in a direction from the inner surface of the parallel portion 88B to the exposed surface of the macnet 92.

  The coil winding portion 80A of the coil frame 80 is inserted into the gap portions 86C and 88C of the yokes 86 and 88 so that the parallel portions 86B and 88B of the yokes 86 and 88 are fitted into the hollow portion 80C. The coil 82 wound around the turning portion 80A is disposed in the magnetic field generated in each of the gap portions 86C and 88C.

  Thus, when a current is passed through the coil 82, a vertical thrust is generated in the coil 82 by the action of the current and the magnetic field (Fleming's left-hand rule), and the coil frame 80 moves in the vertical direction. Note that the direction of movement of the coil frame 80 varies depending on the direction of the current flowing through the coil 82.

  In the VCM 72 configured as described above, a through hole 130 is formed in the connecting portion 80B of the coil frame 80, and is fixed to the holding frame 70 of the vibration-proof lens 28 as shown in FIGS. The pin 132 is inserted into the long hole 130. As a result, the holding frame 70 is connected to the coil frame 80 so as to be movable in the left-right direction. On the other hand, guide shafts 136 and 136 are projected in the vertical direction on the rear fixed cylinder 18, and the guide shafts 136 and 136 penetrate through the projections 134, 134, and 134 that are projected on both side surfaces of the coil frame 80. It is slidably inserted into the hole. Accordingly, the coil frame 80 is supported so as to be movable in the vertical direction along the guide shafts 136 and 136. When the coil frame 80 is moved in the vertical direction by the VCM 72, the vibration-proof lens 28 is moved in the vertical direction in conjunction with this movement.

  The VCM 74 that drives the anti-vibration lens 28 in the left-right direction is completely different in structure from the VCM 72 only in the direction, and the description thereof is omitted. When the anti-vibration lens 28 is driven in the left-right direction by the VCM 74, the anti-vibration lens 28 is moved in the left-right direction as the pin 132 of the holding frame 70 moves in the left-right direction through the long hole 130 of the coil frame 80 (connection portion 80B). Move in the direction.

  The focus lens 32 changes the focal position of the optical system and is supported so as to be movable in the optical axis direction. Further, the focus lens 32 is not mechanically driven but is driven only by electric power by the power of the VCM. FIG. 4 is a schematic front view of the focus lens 32 viewed from the subject side in the optical axis O direction. As shown in the figure, the holding frame 100 of the focus lens 32 is engaged with guide rods 102 and 103 in the direction of the optical axis O installed in the rear fixed cylinder 18, and guides to these guide rods 102 and 103. Thus, the focus lens 32 moves forward and backward in the direction of the optical axis O. The focus lens 32 is driven by the two VCMs 104 and 106, and the position of the focus lens 32 is controlled by controlling the VCMs 104 and 106.

  The VCM 104 includes an air-core coil 110 wound around the outer periphery of the holding frame 100 and a magnetic circuit 112. The magnetic circuit 112 has substantially the same structure as one yoke (for example, yoke 86) of the magnetic circuit 84 in the VCM 72 shown in FIG. 3, and is formed in a U shape as shown in FIGS. Further, a plate-like magnet 116 is fixed inside one of the two parallel portions of the yoke 114, and a magnetic field is generated in a gap portion between the other parallel portion and the magnet 116. The upper side portion of the coil 110 fixed to the holding frame 100 is inserted into the gap of the yoke 114, and the coil 110 is placed in the magnetic field generated in the yoke 114 (by the magnetic circuit 112). A short member 118 for short-circuiting the magnetic path is fixed to the front surface of the yoke 114. The VCM 106 shown in FIG. 4 also includes a magnetic circuit 120 having the same structure except for the orientation of the VCM 104. In the magnetic circuit 120, the left side portion of the coil 110 is inserted into the gap portion of the yoke 122 so that the coil 110 is The magnetic circuit 120 is arranged in the magnetic field generated.

  As a result, when a current is passed through the coil 110, a thrust in the optical axis O direction is generated in the coil 110 due to the action of the current and the magnetic field in the magnetic circuit 112 and the magnetic circuit 120, and the focus lens 32 is moved via the holding frame 100. It moves forward and backward in the direction of the optical axis O.

  Although not described in detail, a focus ring 130 is provided at the distal end of the lens barrel 10 as shown in FIG. 1, and during manual focusing, the rotational position of the focus ring 130 is not shown. The focus lens 32 is moved by the VCMs 104 and 106 to a position corresponding to the detected rotational position of the focus ring 130. In autofocusing, the focus lens 32 is moved to the in-focus position by the VCMs 104 and 106 according to autofocus control in a control unit (not shown).

  In the lens barrel 10 configured as described above, the VCMs 72 and 74 for driving the anti-vibration lens 28 and the VCMs 104 and 106 for driving the focus lens 32 are shown in FIG. Are arranged as follows. As can be seen from this figure, in the lens barrel 10, the VCMs 72 and 74 of the image stabilization lens 28 and the VCMs 104 and 106 of the focus lens 32 are arranged so as not to overlap around the optical axis O. That is, the VCMs 72, 74, 104, and 106 are arranged in order counterclockwise at an angle of approximately 90 degrees with the optical axis O as the center. Therefore, as shown in FIG. 1, when the optical axis O is viewed from the lateral direction, the VCMs 72 and 74 of the anti-vibration lens 28 and the VCMs 104 and 106 of the focus lens 32 overlap in the optical axis O direction (overlapping positions). It becomes possible to arrange in. Thus, by arranging the VCMs 72, 74, 104, and 106 so as to overlap with each other in the optical axis O direction, the VCMs 72 and 74 of the anti-vibration lens 28 can be mirrored by effectively using the space for arranging the VCMs 104 and 106 of the focus lens 32. Even if the VCMs 72 and 74 are increased in size to increase the thrust of the anti-vibration lens 28, the increase in the size of the entire lens barrel 10 can be prevented or reduced. In FIG. 1, the VCM 104 (106) of the focus lens 32 and the VCM 72 (74) of the anti-vibration lens 28 are arranged so as to partially overlap in the optical axis O direction. The distance can be appropriately changed according to the distance between the focus lens 32 and the vibration-proof lens 28. For example, the VCM 104 (106) of the focus lens 32 and the VCM 72 (74) of the anti-vibration lens 28 (the one with the shorter length in the optical axis O direction) is installed in the other VCM in the optical axis O direction. It is also possible to install so as to overlap within the range.

  In the above embodiment, the focus lens 32 is driven in the optical axis direction by the two VCMs 104 and 106. However, the present invention can be applied even when the focus lens 32 is driven by one VCM. Further, the mechanism for driving the focus lens 32 is not limited to the above embodiment.

  Further, the mechanism for driving the anti-vibration lens 28 is not limited to the above embodiment, and the present invention is a mechanism in which the anti-vibration lens 28 is driven in two directions orthogonal to the optical axis by two VCMs. If applicable.

FIG. 1 is a side sectional view showing a lens barrel according to the present invention. FIG. 2 is a schematic front view of the anti-vibration lens as viewed from the subject side in the optical axis direction. FIG. 3 is a perspective view showing the structure of the VCM. FIG. 4 is a schematic front view of the focus lens as viewed from the subject side in the optical axis direction. FIG. 5 is a schematic front view when the VCM of the image stabilizing lens and the focus lens is viewed from the subject side in the optical axis direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Lens barrel, 14 ... Front fixed cylinder, 16 ... Middle fixed cylinder, 18 ... Rear fixed cylinder, 22 ... Zoom lens, 24 ... Aperture, 28 ... Anti-vibration lens, 32 ... Focus lens, 52 ... Zoom ring, 66 ... Iris ring, 70, 100 ... Holding frame, 72, 74, 104, 106 ... Voice coil motor (VCM), 80 ... Coil frame, 80A ... Coil winding part, 80B ... Connection part, 82, 110 ... Coil, 84, 112, 120 ... magnetic circuit, 86, 88, 114, 122 ... yoke, 90, 92, 116 ... magnet

Claims (6)

An image stabilization lens for image blur correction supported so as to be movable in a direction orthogonal to the optical axis in the lens barrel body, and a focus adjusting focus supported so as to be movable in the optical axis direction in the lens barrel body A lens, a first voice coil motor that generates a thrust for moving the vibration-proof lens in a first direction orthogonal to the optical axis, and a direction orthogonal to the optical axis, the first voice coil motor A second voice coil motor that generates a thrust for moving the image stabilizing lens in a second direction orthogonal to the direction; and a third voice that generates a thrust for moving the focus lens in the optical axis direction. A lens barrel including a voice coil motor,
The first to third voice coil motors are arranged around the optical axis so as not to overlap each other when viewed from the optical axis direction, and part or all of the first and second voice coil motors are the light beams. A lens barrel arranged so as to overlap with the third voice coil motor as viewed from the lateral direction of the axis.   2. The lens barrel according to claim 1, wherein each of the first and second voice coil motors includes a magnetic circuit in which two yokes each formed in a U-shape are disposed adjacent to each other.   3. The lens barrel according to claim 1, wherein the first and second voice coil motors are arranged in a direction orthogonal to the optical axis as viewed from the optical axis direction.   4. The lens barrel according to claim 1, wherein the third voice coil motor includes two voice coil motors.   The two voice coil motors constituting the third voice coil motor are respectively arranged symmetrically with the first and second voice coil motors with the optical axis as the center when viewed from the optical axis direction. The lens barrel according to claim 1, 2, 3, or 4.   6. The lens barrel according to claim 1, wherein the anti-vibration lens is disposed in front of the focus lens.

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