JP5822558B2 - Lens barrel and camera system - Google Patents

Description

  The present invention relates to a lens barrel capable of a focus adjustment operation.

  Conventionally, there is a lens barrel that moves a lens group by engaging a cam follower with a cam in order to perform a focus adjustment operation. At this time, if there is a backlash between the cam and the cam follower, a phenomenon such as an unstable tilt of the lens group may occur, and the accuracy of the lens barrel may deteriorate and the desired optical performance may not be obtained. is there. For this reason, in order to suppress tilting due to movement and posture variation between lens groups, an urging member such as a coil spring is arranged between the lens groups and offset, thereby eliminating the backlash between the cam and the cam follower. There is a lens barrel.

  Patent Document 1 discloses a configuration in which a compression coil spring is disposed between a fixed portion and a moving group, and a coil end of the coil spring is engaged with an abutting member to remove backlash in the rotational direction of the cam and the cam follower. Has been. Patent Document 2 discloses a configuration that prevents backlash between a cam and a cam follower by engaging a plurality of tension coil springs with two moving groups and pulling them together.

Japanese Utility Model Publication No. 06-025818 JP 2000-075191 A

  However, in the configuration disclosed in Patent Document 1, a compression coil spring that is an urging member is disposed, so that there is a space for the compression coil spring that is connected around the optical axis between the outer diameter of the lens group and the inner diameter of the lens barrel. Necessary. For this reason, it is difficult to satisfy the demand for downsizing the entire lens unit. Moreover, in the structure represented by the structure of patent document 2, in order to couple | bond the edge part of a tension coil spring with a lens barrel, the operation | work which hooks the hook of a tension coil spring on a lens barrel, and its space are required.

  Accordingly, the present invention provides a lens barrel that can be miniaturized and is highly accurate and easy to assemble.

  A lens barrel according to an aspect of the present invention includes a cam barrel, a lens, a lens barrel that is held by an inner diameter of the cam barrel by a first cam follower, and is movable in the optical axis direction by rotation of the cam barrel. A movable barrel held by a second cam follower on the inner diameter of the cam barrel and movable relative to the barrel, a cylinder body held on one of the barrel or the movable barrel, the barrel or the barrel A slider that is held on the other side of the movable cylinder and can move linearly relative to the cylinder body; and a spring unit in which the cylinder body and a compression coil spring provided inside the slider are integrated.

  A camera system according to another aspect of the present invention includes an imaging device body and the lens barrel attached to the imaging device body in a replaceable manner.

  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 lens barrel that can be miniaturized and is highly accurate and easy to assemble.

It is sectional drawing of the lens-barrel in a present Example. It is a partial exploded view of the lens barrel in the present embodiment. It is an expanded sectional view of the WIDE state of the lens barrel in the present embodiment. It is an expanded sectional view of the TELE state of the lens barrel in the present embodiment. It is sectional drawing of the spring unit 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. The lens barrel of the present embodiment is used as a camera system by being replaceably attached to a camera body (imaging device body) (not shown).

  1 is a cross-sectional view of a lens barrel 100 in the present embodiment, FIG. 2 is a partially exploded view of the lens barrel 100, and FIGS. 5A to 5C are cross-sections of a spring unit 50 provided in the lens barrel 100. FIG. FIG. In FIG. 1, a lens barrel 100 has a mount 2 for attaching to a camera body (not shown), and the mount 2 is provided with a connector 26 for performing communication between the camera body and the lens barrel 100. It has been. The mount 2 is attached to the fixed cylinder 1 with screws while sandwiching the mount ring 3, and the fixed cylinder 1 is fixed to the guide cylinder 4 with screws.

  The guide cylinder 4 has a cam cylinder 5 fitted to the outer diameter thereof, and is configured to be able to rotate at a fixed position while maintaining the position of the optical axis OA (optical axis position) by bayonet engagement. A rectilinear cylinder 6 is held by a first group roller 7 on the outer diameter of the cam cylinder 5, and a first group barrel 9 including a first group lens is further held by the rectilinear cylinder 6. The rectilinear cylinder 6 moves straight in the direction of the optical axis OA (optical axis direction) by the rotation of the cam cylinder 5.

  On the inner diameter of the guide cylinder 4, a second group moving cylinder 10 is held by a cam follower (not shown). A focus cam ring 11 is held on the inner diameter of the second group moving cylinder 10 by a cam follower (not shown). Further, a second group barrel 12 including a second group lens is integrally held on the inner diameter of the focus cam ring 11. As the cam cylinder 5 rotates, the second group moving cylinder 10 also moves in the optical axis direction while rotating. Further, the focus cam ring 11 moves in the optical axis direction along the focus cam 11a by rotating by engaging with a cam follower (not shown) attached to the inner periphery of the second group moving cylinder 10. Further, the inner diameter of the guide cylinder 4 holds the sub cam cylinder 8 by engaging a cam follower (not shown) with the guide cylinder 4 and the cam cylinder 5, and the rotation of the cam cylinder 5 causes the sub cam cylinder 8 (cam cylinder) to be held. Advancing and retreating in the direction of the optical axis while rotating.

  A third group barrel 13 (lens barrel) including a third group lens (lens) is held on the inner diameter of the sub cam barrel 8 by a first cam follower (not shown), and the sub cam barrel 8 rotates to move the sub cam barrel. 8 is moved straight by the same amount as the movement amount in the optical axis direction. Further, the third group lens barrel 13 is provided with a sub-aperture unit 14b configured such that the aperture diameter is changed by the rectilinear movement of the third group lens barrel 13, and an integrally configured aperture unit 14a, and flexible printing is performed. It is connected to the control board 27 by the wiring board 14c (FIG. 2). Further, on the inner diameter of the sub cam cylinder 8, a fourth group moving cylinder 15 (moving cylinder) is held by a second cam follower (not shown), and a cam provided in the sub cam cylinder 8 and a rectilinear groove provided in the guide cylinder 4 are provided. Is engaged with the movement of the sub-cam cylinder 8 in the optical axis direction. The fourth group moving cylinder 15 holds a fourth group connecting cylinder 16. Further, a fourth group barrel 17 including a fourth group lens is fixed to the fourth group connecting cylinder 16. The guide cylinder 4 further holds a focus unit base 30. The focus unit base 30 is configured as a main part of a focus drive unit including a vibration wave motor. A description of the configuration of the focus drive unit is omitted.

  On the outer diameter side of the fixed cylinder 1, a zoom operation ring 24 is bayonet-coupled while being fitted to the fixed cylinder 1 so as to be rotatable at a fixed position. Further, the zoom key (not shown) integrally attached to the zoom operation ring 24 comes into contact with a contact portion that limits the rotation region of the fixed cylinder 1, so that the rotation region is limited. For this reason, the zoom operation ring 24 is configured to be rotatable only in a predetermined rotation region.

  A focus operation ring 21 is arranged on the first unit barrel 9 side of the focus unit base 30, and the focus operation ring 21 rotates at a fixed position by engaging with a fixed position piece (not shown) fixed to the focus unit base 30. I do. The focus operation ring 21 is engaged with the manual communication ring 31 in the rotation direction, and the manual communication ring 31 can be rotated by manually operating the focus operation ring 21. Further, the front ring 18 and the decorative ring 20 are fixed to the front end of the focus unit base 30 on the first group lens barrel 9 side with the reinforcing ring 19 interposed therebetween.

  FIG. 2 is a partial exploded view showing a configuration around the third group barrel 13 and the fourth group barrel 17 in the lens barrel 100. As shown in FIG. 2, a diaphragm unit 14 is fixed to the third group barrel 13. 14 c is a flexible printed wiring board for electrically connecting the aperture unit 14 and the control board 27. The third group barrel 13 is provided with a holding portion 13 a for holding the spring unit 50. The holding portions 13a are provided at three positions around the optical axis between the cam follower holding portions (not shown) of the third group barrel 13 and not interfering with the flexible printed wiring board 14c. That is, the spring unit 50 has the same height as the flexible printed wiring board 14c arranged in the optical axis direction in the direction orthogonal to the optical axis, and is different from the flexible printed wiring board 14c in the circumferential direction of the optical axis. Placed in position. For this reason, interference between the flexible printed wiring board 14c and the spring unit 50 can be avoided. The fourth group moving cylinder 15 is provided with three contact portions 15a at positions around the optical axis with which the spring unit 50 held by the third group lens barrel 13 abuts.

  Next, the configuration of the spring unit 50 will be described with reference to FIG. 5A to 5C are cross-sectional views of the spring unit 50 in each compressed state. FIG. 5A shows a free state of the spring unit 50 that is a state before the spring unit 50 is assembled into the lens barrel 100. FIG. 5B shows a state of the spring unit 50 in the WIDE state (wide angle state). FIG. 5C shows the state of the spring unit 50 in the TELE state (telephoto state).

  5A to 5C, 50a is a cylinder body, 50b is a slider, and 50c is a compression coil spring. As described above, the spring unit 50 includes the cylinder body 50a, the slider 50b, and the compression coil spring 50c. The cylinder main body 50 a is held by a holding portion 13 a provided in the third group barrel 13. The slider 50b is configured to contact (hold) a contact portion 15a provided on the fourth group moving cylinder 15 (fourth group lens barrel) and to move linearly relative to the cylinder body 50a. The compression coil spring 50c is provided inside the cylinder body 50a and the slider 50b.

  The compression coil spring 50c is inserted into the cylinder body 50a, and the slider 50b is incorporated in the cylinder body 50a in a state where the free length of the compression coil spring 50c is compressed. After the slider 50b is incorporated in the cylinder body 50a, the mouth of the cylinder body 50a is crimped. For this reason, the slider 50b does not come off from the cylinder body 50a. As can be seen by comparing FIG. 5A and FIG. 5B, the free length of the compression coil spring 50c is configured to be slightly longer than the length of the compression coil spring 50c in the WIDE state. Yes. Thus, the free length of the spring unit 50 is the maximum distance between the third group barrel 13 (first member) and the fourth group moving cylinder 15 (second member) (the WIDE state in FIG. 5B). ) Longer than. Further, the length of the spring unit 50 at the time of maximum compression is shorter than the minimum distance between the third group barrel 13 and the fourth group moving cylinder 15 (TELE state in FIG. 5C). With such a configuration, the spring unit 50 does not limit the movable range of the third group barrel 13 and the fourth group movable barrel 15. Therefore, the lens barrel 100 can be easily assembled while the urging force of the spring unit 50 always works in the movable range between the third group barrel 13 and the fourth group moving barrel 15. The free length of the compression coil spring 50c is longer than the maximum movable range of the slider 50b with respect to the cylinder body 50a. For this reason, even if the free length of the compression coil spring 50c included is ensured, the free length of the spring unit 50 itself can be limited, and the ease of assembly of the lens barrel 100 can be further improved.

  FIG. 3 is an enlarged cross-sectional view showing the state of the third group barrel 13, the fourth group moving barrel 15, and the spring unit 50 when the lens barrel 100 is in the WIDE state. FIG. 4 is an enlarged cross-sectional view of the same part in the TELE state. As shown in FIGS. 2 to 4, the third group barrel 13 (holding portion 13a) holds the cylinder body 50a, and the fourth group moving barrel 15 (contact portion 15a) expands and contracts on the inner periphery of the cylinder body 50a. The end surface of the slider 50b is held in contact.

  The spring unit 50 of the present embodiment is held between a third group barrel 13 as a first member and a fourth group moving barrel 15 as a second member that can move relative to the first member. ing. The first member may be either a moving member or a fixed member. In this embodiment, the cylinder body 50a is held by the third group barrel 13 as the first member, and the slider 50b is held by the fourth group moving barrel 15 as the second member. However, the present invention is not limited to this. It is not something. The cylinder main body 50a may be configured to be held by one of the first member and the second member, and the slider 50b may be configured to be held by the other one of the first member and the second member.

  Next, an operation when the photographer performs a zoom operation of the lens barrel 100 (when the zoom operation ring 24 is operated) will be described. In FIG. 1, when the zoom operation ring 24 is operated, the rotational force is transmitted to the cam cylinder 5 via a zoom key (not shown), and the cam cylinder 5 is determined by the outer diameter of the guide cylinder 4 connected to the bayonet. Perform position rotation. Further, since the rectilinear cylinder 6 is held by the first group roller 7 on the outer diameter of the cam cylinder 5, and the first group lens barrel 9 including the first group lens is further held by the rectilinear cylinder 6, the first group barrel 9 Moves straight in the direction of the optical axis as the cam barrel 5 rotates.

  A second group moving cylinder 10 is held on the inner diameter of the guide cylinder 4 by a cam follower (not shown), and a focus cam ring 11 is held on the inner diameter of the second group moving cylinder 10 by a cam follower (not shown). Further, a second group barrel 12 including a second group lens is integrally held on the inner diameter of the focus cam ring 11. As the cam cylinder 5 rotates, the second group moving cylinder 10 also moves in the optical axis direction while rotating along a cam (not shown) provided in the guide cylinder 4. At this time, since the key engagement member (not shown) is engaged with the focus key (not shown), the second group barrel 12 held integrally with the focus cam ring 11 moves the focus cam 11a. It moves straight in the direction of the optical axis according to the amount.

  The sub cam cylinder 8 is held on the inner diameter of the guide cylinder 4 by engaging a cam follower (not shown) with the cam provided on the guide cylinder 4 and the cam provided on the cam cylinder 5. The sub cam cylinder 8 advances and retreats in the optical axis direction while rotating by the rotation. A third group lens barrel 13 including a third group lens is held on the inner diameter of the sub cam cylinder 8 by a cam follower (not shown) with respect to a cam provided on the guide cylinder 4 and a straight groove provided on the cam cylinder 5. When the sub cam cylinder 8 rotates, the sub cam cylinder 8 moves straight by the same amount as the movement amount of the sub cam cylinder 8 in the optical axis direction. The sub-aperture unit 14b, which is integrally fixed to the third group lens barrel 13 together with the aperture unit 14a, changes its aperture diameter by a straight movement of the third group lens barrel 13 by a cam provided on the guide cylinder 4, and generates unnecessary luminous flux. Cut.

  A fourth group moving cylinder 15 is held on the inner diameter of the sub cam cylinder 8 by a cam follower (not shown) and engaged with a cam provided on the sub cam cylinder 8 and a rectilinear groove provided on the guide cylinder 4. Then, it moves in the optical axis direction by an amount combined with the movement of the sub cam cylinder 8. The fourth group moving cylinder 15 holds a fourth group connecting cylinder 16, and the fourth group connecting cylinder 16 has a fourth group barrel 17 including a fourth group lens fixed thereto. Further, the slider 50b of the spring unit 50 held by the third group barrel 13 is brought into contact with the fourth group movable barrel 15, and the third group barrel 13 and the fourth group movable barrel 15 are attached in a direction away from each other over the entire movable range. By using the force, the backlash between the cam and the cam follower is removed. By such a rotation operation of the zoom operation ring 24, the first group barrel 9, the second group barrel 12, the third group barrel 13, and the fourth group barrel 17 respectively move straight while changing the mutual interval, The focal length can be changed.

  Next, the case where the photographer operates the focus operation ring 21 will be described again. The focus operation ring 21 has a structure that rotates at a fixed position with the outer diameter of the focus unit base 30, and the photographer can change the focus position by rotating the focus operation ring 21. The rotational force of the focus operation ring 21 works to rotate a focus key (not shown) via a differential operation mechanism of the focus drive unit. The focus key rotates and moves the second group lens barrel 12 (focusing lens group) integrally held by the focus cam ring 11 along the focus cam 11a via a key engaging member (not shown). The focus position can be adjusted by changing the interval with respect to the lens group.

  Next, the operation of the lens barrel 100 when the photographer operates the camera body (imaging apparatus body) and operates the focus drive unit with autofocus based on drive information from the camera body will be described. The above-described vibration wave motor is provided inside the focus drive unit, and the vibration wave motor is driven by a signal that is arithmetically processed inside the lens barrel 100 based on a signal from the camera body. The rotational force of the vibration wave motor acts to rotate the focus key 36 via the differential operation mechanism. Then, by the same action as when the photographer rotates the focus operation ring 21, the second group barrel 12 (focusing lens group) moves forward and backward along the focus cam 11 a provided on the focus cam ring 11, Perform automatic focusing.

  In the present embodiment, the spring unit 50 is arranged around the optical axis with respect to the third group barrel 13 and the fourth group moving cylinder 15, but is not limited thereto. More or fewer spring units 50 may be arranged. In this embodiment, the moving group is held by the three cams and cam followers around the optical axis. For example, using a holding mechanism with a bar and a sleeve, the backlash is effectively reduced only at one place close to the bar. Can be removed. In addition, by holding the cylinder main body on the fixed portion and holding the moving barrel on the cylinder itself, it is possible to configure a lens barrel that can shorten the entire length itself when the barrel is shortened.

  According to the present embodiment, a mechanism that suppresses the tilt of the lens group caused by the fitting backlash can be easily realized in a small size. For this reason, according to the present embodiment, it is possible to provide a lens barrel that can be miniaturized and is highly accurate and easy to assemble.

  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.

DESCRIPTION OF SYMBOLS 13 ... 3 group lens barrel 15 ... 4 group moving cylinder 50 ... Spring unit 50a ... Cylinder main body 50b ... Slider 50c ... Compression coil spring 100 ... Lens barrel

Claims (5)

A cam cylinder,
A lens barrel including a lens, held by a first cam follower on the inner diameter of the cam barrel, and movable in the optical axis direction by rotation of the cam barrel;
A movable barrel held by a second cam follower on the inner diameter of the cam barrel and movable relative to the barrel;
A cylinder main body held on one of the lens barrel or the movable cylinder, a slider held on the other of the lens barrel or the movable cylinder and movable linearly relative to the cylinder main body, and the cylinder main body and the inside of the slider And a spring unit integrated with a compression coil spring provided on the lens barrel.   The spring unit has a height from the optical axis in the direction perpendicular to the optical axis that is the same height as the flexible printed wiring board arranged in the optical axis direction, and at a position different from the flexible printed wiring board in the circumferential direction of the optical axis. The lens barrel according to claim 1, wherein the lens barrel is disposed. The free length of the spring unit is longer than the maximum distance between the lens barrel and the movable cylinder,
3. The lens barrel according to claim 1, wherein a length of the spring unit at the time of maximum compression is shorter than a minimum interval between the barrel and the movable barrel.   The lens barrel according to claim 1, wherein a free length of the compression coil spring is longer than a maximum movable range of the slider with respect to the cylinder body. An imaging device body;
A camera system comprising: the lens barrel according to claim 1, wherein the lens barrel is replaceably attached to the imaging apparatus main body.