JP2005215560A - Lens device, photographing system and photographing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly deform a coil spring as space between 1st and 2nd lens units in an optical axis direction is changed. <P>SOLUTION: The lens device has the 1st lens units (6 and 7), the 2nd lens units (9 and 10) movable in the optical axis direction with respect to the 1st lens unit while rotating around an optical axis, a cam member where a spiral cam for moving the rotating 2nd lens unit in the optical axis direction is formed, and the coil spring 13 arranged to surround an optical path between the 1st and the 2nd lens units and giving urging force in a direction where the 2nd lens unit is separated from the 1st lens unit. Then, the winding direction of the coil spring is the same as that of the spiral of the cam. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lens device, a photographing system, and a photographing device having a structure that suppresses play between a lens unit and a cam that drives the lens unit.

  Conventional lens barrels have a mechanism that supports the lens unit so that it can move in the direction of the optical axis with respect to the fixed member, and has a mechanism for zooming or focusing. The lens unit can be illuminated with screws, helicoids, cams, etc. It is moved in the axial direction.

  Here, when the lens unit is driven using a mechanical mechanism such as a cam, the lens unit drive portion (for example, the cam engagement portion) has a backlash, so the lens unit misalignment and light Errors and fluctuations such as tilting with respect to the axis and eccentricity may occur, which may adversely affect the optical performance of the zoom lens barrel.

  Therefore, as a means for suppressing the above-described play, there is one that places a coil spring between a plurality of lens holding members that move linearly in the optical axis direction and urges these lens holding members in directions away from each other (for example, Patent Document 1). That is, the play in the driving portion is removed by moving the lens holding member one by one.

  On the other hand, in the configuration in which the plurality of lens holding members are moved only in the optical axis direction during zooming or the like, there is a limit to downsizing the lens barrel. Therefore, there is a structure shown in FIGS. 6A to 6C as a structure capable of further reducing the size of the lens barrel. FIG. 6A is a cross-sectional view of the zoom lens barrel in the optical axis direction, the lower side from the line AA showing the wide state, and the upper side showing the tele state.

  The arm portion 36a of the second lens holding barrel 36 that holds the second lens unit 32 is engaged with a rectilinear guide groove portion 33a extending in the optical axis direction of the fixed barrel 33, and a cam follower pin 37 provided on the arm portion 36a is , Engaged with the cam groove portion 34a of the cam barrel 34 that rotates around the optical axis during zooming. For this reason, the second lens holding barrel 36 (second lens unit 32) moves only in the optical axis direction during zooming.

A pair of cam follower portions 35 a are provided on the outer periphery of the first lens holding barrel 35 that holds the first lens unit 31, and the cam follower portions 35 a are provided on the inner peripheral surface of the second lens holding barrel 36. The convex cam 36c is engaged so as to be sandwiched in the optical axis direction. Further, the hole 35 b of the first lens holding barrel 35 is engaged with a support portion 38 a extending in the optical axis direction of the zoom key 38 that rotates around the optical axis together with the cam barrel 34. Thereby, the first lens holding barrel 35 moves in the optical axis direction while rotating around the optical axis during zooming.
Japanese Patent Laid-Open No. 10-20173 (paragraph number 0017, FIG. 3)

  However, in the configuration shown in FIG. 6, when a coil spring is simply arranged between the lens holding barrels 35 and 36, the first lens holding barrel 35 rotates around the optical axis while moving in the optical axis direction. The following problems occur. That is, an excessive stress is applied to the coil spring by the operation of the first lens holding barrel 31 (rotation around the optical axis and movement in the optical axis direction), and the deformation of the coil spring due to a change (interval change) between the lens holding barrels. May not be performed smoothly. Then, since the coil spring is not deformed smoothly, the operation of the first lens holding barrel 31 may not be performed smoothly.

  The lens device of the present invention includes a first lens unit, a second lens unit that can move in the optical axis direction relative to the first lens unit while rotating around the optical axis, and the rotating second lens unit. A cam member formed with a spiral cam that is moved in the axial direction, and disposed so as to surround an optical path between the first lens unit and the second lens unit, and the second lens unit is disposed in the first lens unit. A coil spring that applies an urging force in a direction away from the coil spring, and the winding direction of the coil spring and the winding direction of the spiral of the cam are the same.

  Here, an imaging system can be configured by the lens apparatus and an imaging apparatus that can be attached to the lens apparatus and includes a photoelectric conversion element that photoelectrically converts a subject image formed by the lens apparatus. In addition, it is possible to configure an imaging apparatus including the lens device and a photoelectric conversion element that photoelectrically converts a subject image formed by the lens device.

  According to the present invention, by making the winding direction of the coil spring and the winding direction of the spiral of the cam the same, the coil spring is smoothly deformed in accordance with the change in the distance between the first lens unit and the second lens unit in the optical axis direction. Can be made. And the play of a 1st lens unit and a 2nd lens unit can be suppressed.

  Examples of the present invention will be described below.

  A lens barrel that is Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view of the lens barrel of the present embodiment. FIG. 2 is a diagram for explaining the lens barrel in the wide state.

  Here, FIG. 2A is a view (front view) when the lens barrel is viewed from the object side. 2B and 2C are cross-sectional views in the optical axis direction of the lens barrel, FIG. 2B is a view taken along a plane including BB in FIG. 2A, and FIG. It is a figure when cut | disconnecting in the surface containing CC. FIG. 2C also shows a schematic diagram of a camera to which a lens barrel is attached. FIG. 2D is a diagram when the lens barrel is viewed from the image plane side.

  FIG. 3 is a diagram for explaining the lens barrel in the tele state. Here, FIG. 3A is a view (front view) when the lens barrel is viewed from the object side. 3B and 3C are cross-sectional views in the optical axis direction of the lens barrel, FIG. 3B is a view taken along a plane including BB in FIG. 3A, and FIG. It is a figure when cut | disconnecting in the surface containing CC.

  In FIG. 1 to FIG. 3, parts that are not directly related to the features of the present embodiment are omitted for easy understanding of the characteristic portions of the present embodiment.

  The lens barrel of this embodiment is detachably attached to the camera 21 via the lens mount 1 as shown in FIG. The first lens unit 9 and the second lens unit 6 arranged in the lens barrel are moved in the optical axis direction (AA direction) by the rotation of the zoom ring 4 around the optical axis. The focal length of the photographic optical system can be changed by changing the distance between the lens units 9 and 6.

  Here, the two lens units 9 and 6 are configured to move in the optical axis direction. However, the present invention is not limited to this, and a plurality of (three or more) lens units are moved in the optical axis direction. It can be applied even if it exists.

  In FIG. 2C, a low-pass filter (optical filter) 22 and an image sensor 23 such as a CCD or CMOS sensor are arranged in the camera 21. The subject light that has passed through the lens barrel passes through the low-pass filter 22 and enters the light receiving surface of the image sensor 23. The image sensor 23 receives subject light and converts it into an electrical signal by photoelectric conversion, and outputs the accumulated charge.

  An output signal of the image sensor 23 is input to an image processing circuit (not shown), and image data is generated by image processing in the image processing circuit. The image data is displayed on a display unit (not shown) provided in the camera 21 or recorded on a recording medium (not shown).

  In FIG. 1, reference numeral 2 denotes a focus washer for correcting the focus position of the lens barrel. The mount 1 sandwiches a pin washer 2 together with a fixed cylinder 3 as a main body of the lens barrel, and is fixed to the fixed cylinder 3 with screws 15. By mounting the mount 1 on the camera 21, the fixed cylinder 3 is fixed to the camera 21.

  A zoom ring 4 is engaged with the outer peripheral surface 3a of the fixed cylinder 3 on the inner peripheral surface 4a. The zoom ring 4 can rotate around the optical axis by receiving a driving force from a driving source (not shown). A zoom roller 5 is attached to the groove 3 b formed on the outer peripheral surface 3 a of the fixed cylinder 3, and the zoom roller 5 engages with a hole 4 b extending in the circumferential direction of the zoom ring 4. Thereby, the zoom ring 4 is rotatably supported around the optical axis with respect to the fixed cylinder 3.

  Reference numeral 6 denotes a second moving lens unit, which is integrally supported by a second holding barrel 7. The second moving lens unit 6 and the second holding barrel 7 correspond to the first lens unit described in the claims. A first moving lens unit 9 is integrally supported by the first holding barrel 10. The first moving lens unit 9 and the first holding barrel 10 correspond to the second lens unit described in the claims. The second holding barrel 7 and the first holding barrel 10 are formed by molding.

  Arm portions 7a are formed at three locations in the circumferential direction of the second holding barrel 7, and each arm portion 7a is provided at three locations in the circumferential direction of the fixed barrel 3 and is associated with a rectilinear groove portion 3c extending in the optical axis direction. Match.

  The second holding barrel 7 can be moved only in the optical axis direction by the engagement of the arm portion 7a and the rectilinear groove portion 3c.

  A cam roller 8 is fixed to the arm portion 7 a of the second holding barrel 7 and engages with a cam groove portion 4 c provided on the inner peripheral surface of the zoom ring 4. Therefore, when the zoom ring 4 rotates around the optical axis, the cam roller 8 is guided by the cam groove 4c, and the second holding barrel 7 moves in the optical axis direction according to the lead of the cam groove 4c and the rotation amount of the zoom ring 4. Will do.

  A plurality of convex cam portions 7 c are integrally formed on the inner peripheral surface of the second holding barrel 7, and each convex cam portion 7 c is integrally formed on the outer peripheral surface of the first holding barrel 10. The cam follower 10a is engaged.

  Reference numeral 11 denotes a key receiving plate which is integrally attached to the first holding barrel 10 incorporated in the second holding barrel 7 by engagement of the convex cam portion 7c and the cam follower 10a with screws or the like. Reference numeral 12 denotes a zoom key, and the convex portion 12a is fixed to the concave portion 4d of the zoom ring 4 via a screw or the like. As a result, the zoom key 12 rotates around the optical axis together with the zoom ring 4.

  A guide portion 12 b extending in the optical axis direction of the zoom key 12 is engaged with a concave portion 11 a of the key receiving plate 11. Thereby, the rotational force of the zoom ring 4 is transmitted to the first holding barrel 10 via the zoom key 12, and the first holding barrel 10 rotates around the optical axis.

  Here, since the first holding barrel 10 is engaged with the convex cam portion 7c via the cam follower 10a, the first holding barrel 10 rotates around the optical axis and moves in the optical axis direction. In other words, the first holding barrel 10 can move in the optical axis direction while rotating around the optical axis by the lead of the convex cam portion 7 c with respect to the second holding barrel 7. In the present embodiment, the convex cam portion 7 c for driving the first holding barrel 10 is formed on the inner peripheral surface of the second holding barrel 7, but the first holding barrel 7 is separate from the first holding barrel 7. A cam member for driving the holding barrel 10 may be provided.

  Reference numeral 13 denotes a compression coil spring, which is disposed between the second holding barrel 7 and the first holding barrel 10. At both ends thereof, the optical axis orthogonal surface (receiving surface) 7 d of the second holding barrel 7 and the first holding mirror are provided. The tube 10 is in contact with the optical axis orthogonal surface (receiving surface) 10b. Here, both end portions of the compression coil spring 13 in contact with the optical axis orthogonal surfaces 7d and 10b are formed to have an optical axis orthogonal surface by grinding or the like. Thereby, the spring force of the compression coil spring 13 can be efficiently transmitted to the second holding barrel 7 and the first holding barrel 10. FIG. 4 shows an external perspective view of the compression coil spring 13.

  Further, since the compression coil spring 13 has a natural length longer than the maximum distance between the optical axis orthogonal surface 7d and the optical axis orthogonal surface 10b (the lens units 6 and 9 are farthest apart in the optical axis direction), the first holding mirror The tube 10 and the second holding barrel 7 are urged in a direction away from each other in the optical axis direction. Further, the compression coil spring 13 is disposed so as to surround the optical path of the photographing optical system in the lens barrel, and is disposed so as not to block the subject light flux passing through the optical path.

  Here, the lead direction of the convex cam portion 7c (winding direction, indicated by a dotted line in FIG. 2B) and the winding direction of the compression coil spring 13 are the same direction. That is, the compression coil spring 13 extends while rotating in the direction of the arrow X in FIG. 1 from the image plane side to the object side. The convex cam portion 7c also extends from the image plane side to the object side while rotating in the arrow X direction in FIG. In other words, the convex cam portion 7c and the compression coil spring 13 are right-handed (clockwise wound) when viewed from the image plane side.

  In the case where the holding barrels (7, 10) that are in contact with both ends of the compression coil spring 13 are moved only in the optical axis direction as in the prior art, compression is performed in accordance with the change in the interval in the optical axis direction of these holding barrels. The coil spring expands and contracts, and only the torsional force of the wire constituting the spring (force in the direction of separating in the optical axis direction described above) acts on each holding barrel. For this reason, the compression coil spring can be used as a spring having a stable spring constant.

  However, in this embodiment, since one end of the compression coil spring 13 is in contact with the first holding barrel 10 that moves in the optical axis direction and rotates around the optical axis, the above-described twisting force is applied to the compression coil spring 13. In addition to this, bending stress accompanying rotation of the first holding barrel 10 occurs. That is, one end of the compression coil spring 13 receives a force that is displaced in the circumferential direction of the coil spring 13 due to friction with the first holding barrel 10.

  In the lens barrel of this embodiment, when the distance between the first holding barrel 10 and the second holding barrel 7 in the optical axis direction is narrowed, the first holding barrel 10 is clockwise when viewed from the object side (FIG. 4). (The direction corresponding to the direction of the arrow X1) is approaching the second holding barrel 7.

  At this time, the overall length of the compression coil spring 13 is gradually shortened, and the diameter of the compression coil spring 13 is increased. Further, on one end side of the compression coil spring 13, a stress that bulges outward in the radial direction of the compression coil spring 13 due to the force in the direction of the arrow X <b> 1 in FIG. 4 due to friction with the first holding barrel 10 acts.

  That is, it is possible to cope with the increase in the diameter of the compression coil spring 13 described above by generating a stress that causes the compression coil spring 13 to bulge outward in the radial direction of the compression coil spring 13.

  On the other hand, when the interval between the first holding barrel 10 and the second holding barrel 7 in the optical axis direction is increased, the first holding barrel 10 is counterclockwise (corresponding to the arrow Y direction in FIG. 4). The second holding barrel 7 while rotating in the direction).

  At this time, the overall length of the compression coil spring 13 gradually increases and the diameter of the compression coil spring 13 decreases. Further, on one end side of the compression coil spring 13, a stress that enters the radially inner side of the compression coil spring 13 due to the force in the direction of arrow Y in FIG. 4 due to friction with the first holding barrel 10 acts.

  That is, it is possible to cope with the decrease in the diameter of the compression coil spring 13 described above by generating a stress that enters the radially inner side of the compression coil spring 13 on one end side of the compression coil spring 13.

  According to the present embodiment, the first holding lens barrel 10 is operated as described above, so that the first holding lens barrel 10 can be operated in the opposite direction to the first holding lens barrel 10. The stress applied to the compression coil spring 13 can be reduced when the compression coil spring 13 is deformed (change in diameter) in accordance with the change in the interval between the second holding barrels 7. That is, the compression coil spring 13 can be smoothly deformed according to the change in the distance between the first holding barrel 10 and the second holding barrel 7. In addition, by causing the compression coil spring 13 to be smoothly deformed, the operation of the first holding barrel 10 in contact with the compression coil spring 13 (rotation around the optical axis and movement in the optical axis direction) can be performed smoothly. Can do.

  Thereby, even when the first holding barrel 10 rotates in the optical axis direction while rotating around the optical axis, the first holding barrel 10 and the second holding barrel 7 are separated in the optical axis direction by the compression coil spring 13. The first holding barrel 10 and the second holding barrel 7 can be positioned in the optical axis direction.

  In addition, by applying a lubricant such as oil to the contact surfaces 7d and 10b or by providing a sliding member, the frictional force with both ends of the compression coil spring 13 can be reduced. The operation of the first holding barrel 10 can be performed smoothly.

  A second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the configuration of the compression coil spring is changed as compared with the first embodiment. In FIG. 5, the side view (A) and external appearance perspective view (B) of the compression coil spring in a present Example are shown.

  The compression coil spring 14 shown in FIG. 5 is formed so that the end portions 14a and 14b extend in the optical axis direction. The configuration of the other lens barrel is the same as that of the first embodiment, and the same members as those described in the first embodiment will be described using the same reference numerals.

  The end portion 14 a engages with a hole formed in the first holding lens barrel 10, and the end portion 14 b engages with a hole formed in the second holding lens barrel 7. Also in the present embodiment, the first holding barrel 10 moves in the optical axis direction while rotating around the optical axis with respect to the second holding barrel 7 as in the first embodiment.

  Here, since the end 14a of the compression coil spring 14 is engaged with the first holding barrel 10, an urging force in one direction around the optical axis can always be applied to the first holding barrel 10. .

  That is, when the first holding barrel 10 approaches the second holding barrel 7 while rotating in the arrow Y direction (clockwise as viewed from the object side) in FIG. In the same manner as described in 1, the diameter is deformed so as to increase. At this time, a biasing force in the direction of the arrow X acts on the first holding barrel 10 through the end portion 14 a by the restoring force of the compression coil spring 14.

  When the first holding barrel 10 is moved away from the second holding barrel 7 while rotating in the direction of the arrow X in FIG. 5B (counterclockwise as viewed from the object side), the compression coil spring 14 is In the same manner as described in 1, this diameter is deformed to be small. At this time, the urging force in the direction of arrow Y acts on the first holding barrel 10 through the end portion 14 a by the restoring force of the compression coil spring 14.

  On the other hand, since the second holding barrel 7 is also engaged with the compression coil spring 14, the deformation of the compression coil spring 14 accompanying the operation of the first holding barrel 10 receives a biasing force in one direction around the optical axis. .

  According to the present embodiment, as described above, the backlash around the optical axis can be suppressed by urging the first holding barrel 10 and the second holding barrel 7 in one direction around the optical axis. That is, play around the optical axis between the cam follower 10a and the convex cam portion 7c and play around the optical axis between the cam roller 8 and the cam groove portion 4c can be suppressed.

  Similarly to the first embodiment, the biasing force in the optical axis direction of the compression coil spring 14 can suppress the play in the optical axis direction of the first holding barrel 10 and the second holding barrel 7.

  In the above-described embodiment, the lens barrel that is detachably attached to the camera 21 has been described. However, the present invention can also be applied to a lens-integrated camera. In the above embodiment, the second holding barrel 7 is moved only in the optical axis direction, and the first holding barrel 10 is rotated in the optical axis direction while rotating around the optical axis. It is not limited. For example, two holding barrels that are in contact with both ends of the compression coil spring may be configured to move in the optical axis direction while rotating around the optical axis. Also in this case, as described in the first embodiment, it is necessary to match the winding direction of the cam for driving each holding barrel with the winding direction of the compression coil spring.

1 is an exploded perspective view of a lens barrel that is Embodiment 1 of the present invention. A view of the lens barrel in the wide state as viewed from the object side (A), a BB cross-sectional view (B) in (A), a CC cross-sectional view (C) in (A), an image plane side (D) seen from FIG. The figure which looked at the lens barrel in the tele state from the object side (A), BB sectional view (B) in (A), CC sectional view (C) in (A). 1 is an external perspective view of a compression coil spring in Embodiment 1. FIG. The side view (A) and external appearance perspective view (B) of the compression coil spring in Example 2 of this invention. Sectional view in the optical axis direction of a conventional lens barrel (A), a development view of a cam barrel (B), and a development view of a second lens holding barrel (C).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mount 2 ... Focus washer 3, 33 ... Fixed cylinder 4, 34 ... Zoom ring 5. Zoom roller 6, 32 ... Second lens group 7, 36 ... Second holding barrel 8, 37 ... · Cam rollers 9 and 31 · · First lens group 10 and 35 · · First holding barrel 11 · · Key receiving plate 12 and 38 · · Zoom keys 13 and 14 · · Compression coil spring

Claims (8)

A first lens unit;
A second lens unit movable in the optical axis direction with respect to the first lens unit while rotating around the optical axis;
A cam member formed with a spiral cam for moving the rotating second lens unit in the optical axis direction;
A coil spring disposed so as to surround an optical path between the first lens unit and the second lens unit, and applying a biasing force in a direction separating the second lens unit from the first lens unit;
The lens apparatus according to claim 1, wherein a winding direction of the coil spring and a winding direction of the spiral of the cam are the same. The first lens unit is prevented from rotating about the optical axis;
2. The coil spring according to claim 1, wherein one end and the other end of the coil spring engage with the first lens unit and the second lens unit, respectively, to apply a biasing force acting on the second lens unit in one direction of rotation. The lens device described.   3. The lens device according to claim 2, wherein one of the rotation directions is a direction in which the cam follower portion of the second lens unit is pressed against the cam.   4. The lens device according to claim 1, wherein the first lens unit and the second lens unit are provided with receiving surfaces that are orthogonal to the optical axis and receive end faces of the coil springs. 5. .   The lens apparatus according to claim 4, wherein a lubricant is applied to the receiving surface.   The lens device according to claim 4, wherein a sliding member is provided on the receiving surface. A lens apparatus according to any one of claims 1 to 6;
A photographing system comprising: a photographing device that can be attached to the lens device and includes a photoelectric conversion element that photoelectrically converts a subject image formed by the lens device. A lens apparatus according to any one of claims 1 to 6;
An imaging apparatus comprising: a photoelectric conversion element that photoelectrically converts a subject image formed by the lens device.

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