JP5053953B2 - Lens barrel, interchangeable lens and camera system - Google Patents

Description

  The present invention relates to a lens barrel provided with a plurality of optical elements. In particular, the present invention relates to a lens barrel having an adjustment structure for correcting an interval shift and a tilt of each optical element caused by a manufacturing error.

  In a zoom lens used for an interchangeable lens for a single-lens reflex camera or the like, it is necessary to improve the holding accuracy of each lens group constituting the zoom lens in accordance with recent needs for improving image quality. For this reason, there has been proposed an adjustment structure for correcting an interval shift and a tilt of each lens group caused by a manufacturing error.

  In Patent Document 1, an adjustment cam portion is engaged with a cylindrical member having an adjustment cam portion arranged at three locations in the circumferential direction and a fixing groove portion arranged at three locations between the adjustment cam portions. A lens barrel having a lens holding frame to which an eccentric roller is fixed is disclosed. By rotating the eccentric roller, the tilt of the lens holding frame is adjusted, and by moving the eccentric roller within the adjustment cam portion, the position of the lens holding frame in the optical axis direction is adjusted. After the adjustment is completed, the lens holding frame and the cylindrical member are integrated by fastening a fixing screw inserted into the lens holding frame into the fixing groove.

In Patent Document 2, a cylindrical member having a long hole extending in the optical axis direction, two circumferentially extending convex portions in contact with the inner surface of the cylindrical member, and a lens holding frame having a circumferential groove sandwiched between the convex portions, A lens barrel including a connecting member that engages with a circumferential groove is disclosed. A screw hole is provided in the center of the connecting member, and after adjusting the position of the lens holding frame in the optical axis direction with respect to the cylindrical member, the connecting member is fixed to the cylindrical member by passing a screw through the long hole. . Since the connecting member is engaged with the circumferential groove of the lens holding frame and is fixed to the cylindrical member with screws, the relative position of the lens holding frame and the cylindrical member in the optical axis direction is fixed.
JP 2005-227400 A JP 2006-71772 A

  However, in Patent Document 1, as described above, after the tilt adjustment is performed, the lens holding frame and the cylindrical member are directly fixed by screws, so that the fixing screws enter the cylindrical member obliquely. It will be. As a result, although the tilt adjustment is performed, the tilt of the lens may change depending on the tilt adjustment amount and the screw tightening torque.

  In Patent Document 2, after adjusting the distance, the position of the cylindrical member and the lens holding frame in the optical axis direction is indirectly fixed by fixing the connecting member with a screw. Since no force is directly applied to the lens holding frame itself, the lens holding frame can be fixed without causing unnecessary distortion. However, since the connecting member is structured to engage with the circumferential groove, the tilt adjustment cannot be performed.

  In view of the above problems, an object of the present invention is to provide a lens barrel that has a structure that allows tilt adjustment and interval adjustment and that can be reliably fixed while maintaining the adjusted state.

To achieve the above object, a lens barrel of the present invention includes a holding frame that holds a lens, a support member provided with a guide groove, a first engagement that engages with the guide groove and is attached to the holding frame. And a second engaging member that engages with the holding frame so as to restrict the movement of the holding frame only in the rotation direction about the optical axis.

  Then, the relative position of the holding frame and the support member in the optical axis direction is adjusted by moving the first engagement member along the guide groove along with the relative rotation of the holding frame and the support member. By rotating the engaging member, the relative tilt between the holding frame and the supporting member is adjusted, and the second engaging member is fixed to the supporting member, thereby fixing the holding frame to the supporting member. It is characterized by that.

  According to the present invention, the tilt adjustment and the interval adjustment are possible, and the fixing can be reliably performed while the adjustment state is maintained.

  Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing a camera system including an interchangeable lens for a single-lens reflex camera according to an embodiment of the present invention and a camera body to which the interchangeable lens is attached. FIG. 2 is a partial enlarged cross-sectional view of a portion A shown in FIG. FIG. 3 is an exploded perspective view of the main part of FIG.

  Reference numeral 100 denotes a camera body to which the interchangeable lens of this embodiment is detachably attached. The camera body 100 has an image sensor 100a.

  The interchangeable lens of the present embodiment is a five-group interchangeable lens having first to fifth lens groups L1 to L5 in order from the object side. All the lens groups L1 to L5 move in the optical axis direction during the zoom operation. The second lens unit L2 moves in the optical axis direction during the focusing operation. During the zoom operation, the third lens unit L3 and the fifth lens unit L5 move together. The fourth lens group L4 is divided into two partial groups, a 4a lens group L4a and a 4b lens group L4b. The 4a lens group L4a, which is a group located on the object side, is a movement in the optical axis direction. Separately, it also moves in the direction perpendicular to the optical axis in order to perform an image blur correction operation.

  Reference numeral 101 denotes a mount, which has a bayonet portion to be attached to the camera body 100 and is fixed to the fixed cylinder 102 with screws.

  Reference numeral 103 denotes an exterior ring, which is sandwiched and fixed between the mount 101 and the fixed cylinder 102. A SW panel 104 is attached to the exterior ring 103 as shown in FIG. 3, and functions such as autofocus and shake correction can be selected and used by switching a switch provided on the SW panel 104. it can.

  Reference numeral 105 denotes a guide tube, and the fixed tube 102 is screwed to form a fixed portion with respect to the camera body 100. A first cam cylinder 106 that can be rotated around the optical axis by a roller (not shown) is fitted to the outer periphery of the guide cylinder 105.

  Accordingly, when the first cam cylinder 106 is rotated, the intersection of the guide groove in the optical axis direction provided in the guide cylinder 105 and the cam groove provided in the first cam cylinder 106 moves. In accordance with the movement of the intersection, the third group holding frame 107 that holds the third lens group L3 can be moved in the optical axis direction through a screwed roller. Similarly, the shake correction unit 108 that holds the fourth lens unit L4 and the first rectilinear cylinder 109 can be moved in the optical axis direction via rollers that are screwed to each.

  On the third group holding frame 107, an electromagnetic diaphragm unit 110 including a diaphragm driving unit and a diaphragm blade unit is fixed with screws.

  Further, at the rear end of the extended portion 107 a of the third group holding frame 107, a fifth group holding frame 111 that holds the fifth lens group L 5 is held by a fifth group holding plate 112 that is screwed to the third group holding frame 107. It is held by being.

  The shake correction unit 108 holds the 4a lens group L4a so that it can be driven in the direction orthogonal to the optical axis, and drives the 4a lens group L4a by a drive unit including a magnet and a coil. A 4b group holding frame 113 that holds the 4b lens group L4b is screwed to the rear end via a reinforcing plate 114.

  On the outer periphery of the first rectilinear cylinder 109, the position of the second cam cylinder 115 in the optical axis direction is regulated with respect to the first rectilinear cylinder 109 by a known bayonet structure, and the rotation of the first cam cylinder 106 is transmitted. So that it can be rotated.

  The first rectilinear cylinder 109 is provided with a guide groove extending in the optical axis direction, and the second cam cylinder 115 is provided with a cam groove. As a result, when the second cam cylinder 115 rotates, the intersection of the rectilinear groove of the first rectilinear cylinder 109 and the second cam cylinder 115 moves. According to the movement of the intersection point, the second rectilinear cylinder 116 can be moved in the optical axis direction through a roller (not shown) that is screwed.

  Near the tip of the second rectilinear cylinder 116, a first group holding frame 117 that holds the first lens group L1 is held via a roller. That is, the second rectilinear cylinder 116 is a support member for the first group holding frame 117. Further, the filter frame 118 is fixed with a screw (not shown). A bayonet portion is provided on the outer periphery of the front end of the filter frame 118, and a screw portion is provided on the inner periphery thereof.

  The detailed structure related to the adjustment and fixing of the second rectilinear cylinder 116 and the first group holding frame 117 is a main point of the present invention, and the details will be described later.

  Reference numeral 119 denotes a decorative ring on which a display such as a lens name is printed on the front surface.

  Reference numeral 120 denotes a zoom operation ring, which is rotatably held with respect to the fixed cylinder 102 by a known bayonet structure.

  The zoom operation ring 120 is formed with a recess for engaging a zoom key (not shown) screwed to the first cam cylinder 106. Accordingly, the cam cylinder 106 can be rotated integrally with the zoom operation ring 120 via the zoom key.

  A zoom rubber 121 is wound around the outer periphery of the zoom operation ring 120.

  Reference numeral 122 denotes an elastic member that is in compression contact with a bayonet coupling flange surface provided on the zoom operation ring 120 and is held in a bayonet restricting portion provided on the fixed cylinder 102.

  Reference numeral 123 denotes a focus cam cylinder, and a cam groove is provided in the cylindrical portion. A roller (not shown) provided on the outer periphery of the first cam cylinder 106 is engaged with the cam groove. Further, the key portion extending from the focus cam cylinder 123 engages with the focus key 125 attached to the focus ring 124 attached to the fixed cylinder 102 so as to be rotatable by a known bayonet structure. ing.

  A second group holding frame 126 holds the second lens group L2, and is fixed to the focus cam cylinder 123. As a result, the second group holding frame 126 advances and retreats in the optical axis direction when the first cam cylinder 106 rotates (the focus ring 124 stops). The amount of advancement / retraction at this time is the change in the optical axis direction of the first cam cylinder 106 itself and the engagement point of the roller provided in the first cam cylinder 106 engaged with the cam groove of the focus cam cylinder 123. It is determined by the total amount.

  Further, when the focus ring 124 is rotated (the first cam cylinder 106 is stopped), the optical axis direction of the engaging point of the roller provided in the first cam cylinder 106 that engages with the cam groove of the focus cam cylinder 123 while rotating. Advance and retreat according to the amount of change.

  In the interchangeable lens of the present embodiment, the focal position shift accompanying the focal length change in the inner focus is mechanically compensated in this way, and the second lens unit L2 is advanced and retracted in the optical axis direction.

  A main board 127 is electrically connected to the electromagnetic diaphragm unit 110, the shake correction unit 108, and the like via a flexible flexible board, and performs various controls.

  A contact block 128 is screwed to the mount 101 and connected to the main board 127 via a flexible board, and is provided for communication with the camera body and power supply.

  A back cover 129 is elastically coupled to the mount 101 to cut off harmful light. Reference numeral 130 denotes a protective rubber ring that is elastically coupled to the back cover 129.

  In the interchangeable lens configured as described above, when the zoom operation ring 120 is rotated, the first cam cylinder 106 is rotated via the zoom key, and all the lens groups L1 to L5 are advanced and retracted in the optical axis direction according to the mechanism. Zooming is performed. At this time, the third lens unit L3 and the fifth lens unit L5 advance and retract integrally.

  On the other hand, the focus ring 124 is rotated by driving a motor (not shown) during autofocus and manually during manual focus. Thereby, according to the mechanism, the second lens unit L2 advances and retracts, and focusing can be performed.

  Next, with reference to FIG. 2 and FIG. 3, a detailed structure relating to adjustment and fixing of the relative position and relative tilt of the second rectilinear cylinder 116 and the first group holding frame 117, which are features of the present invention, will be described.

  At the tip of the second rectilinear cylinder 116, adjustment cam portions 116a, which are guide grooves for adjusting the relative position, are arranged at three equal intervals in the circumferential direction. Further, at least one fixing groove 116b is formed between the adjustment cam portions 116a.

  The first group holding frame 117 allows the eccentric roller 131 that engages with the adjustment cam portion 116 a to enter the roller seat 117 a of the first group holding frame 117 and is fixed by the screw 132 so that it does not fall off from the second rectilinear cylinder 116. Combined. That is, the eccentric roller 131 is a first engaging member that engages with the adjustment cam portion 116 a and is attached to the first group holding frame 117.

  The eccentric roller 131 and the screw 132 are provided at three locations so as to face the adjusting cam portion 116a.

  By rotating the eccentric roller 131, optical adjustment for correcting the relative tilt between the first group holding frame 117 and the second rectilinear cylinder 116, that is, the tilt of the first lens unit L1 with respect to the optical axis can be performed.

  Further, as the first group holding frame 117 and the second rectilinear cylinder 116 are rotated relative to each other, the eccentric roller 131 is moved along the adjustment cam portion 116a, whereby the first group holding frame 117 and the second rectilinear cylinder 116 are moved. The relative position can be adjusted. That is, the relative distance between the adjacent second lens unit L2 can be adjusted by moving the first lens unit L1 in the optical axis direction.

  Further, the first group holding frame 117 is formed with a recess 117b at a position facing the fixing groove 116b. A fixing nut 133 is fitted in the recess 117b.

  The fixing nut 133 is restricted to move only in the rotational direction around the optical axis in the recess 117b, and the optical axis direction and the radial direction are slightly between the first group holding frame 117 and the second rectilinear cylinder 116. Dimensioned to have a play. That is, the fixing nut 133 is a second engaging member that engages with the first group holding frame so as to restrict the movement of the first group holding frame 117 only in the rotation direction.

  After the optical adjustment, the fixing nut 133 is pulled into and fixed to the second rectilinear cylinder 116 by a screw 134 that passes through the fixing groove 116b. At this time, since the fixing nut 133 is restricted from moving in the rotation direction about the optical axis in the recess 117b, the rotation of the first group holding frame 117 around the optical axis is restricted.

  Further, the fixing nut 133 is set to have a slight play between the first group holding frame 117 and the second rectilinear cylinder 116 in the optical axis direction and the radial direction in the recess 117b. Without applying a force directly to 117, fixing is possible while maintaining the state after optical adjustment.

  With such a configuration, a lens barrel that can be securely fixed while maintaining the adjustment state while realizing tilt adjustment and interval adjustment is realized.

It is sectional drawing of the interchangeable lens for single-lens reflex cameras. It is a partial expanded sectional view of FIG. It is a principal part disassembled perspective view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Camera body 101 Mount 102 Fixed cylinder 103 Exterior ring 104 SW panel 105 Guide cylinder 106 1st cam cylinder 107 3rd group holding frame 108 Shake correction unit 109 1st rectilinear cylinder 110 Electromagnetic aperture unit 111 5th group holding frame 112 5th group holding plate 113 4b group holding frame 114 reinforcing plate 115 second cam cylinder 116 second rectilinear cylinder 117 first group holding frame 118 filter frame 119 decorative ring 120 zoom operation ring 121 zoom rubber 122 elastic member 123 focus cam cylinder 124 focus ring 125 focus key 126 2 Group holding frame 127 Main board 128 Contact block 129 Back cover 130 Protective rubber ring 131 Eccentric roller 132 Screw 133 Fixing nut 134 Screw

Claims (6)

A holding frame for holding the lens;
A support member provided with a guide groove;
A first engaging member that engages with the guide groove and is attached to the holding frame;
A second engagement member that engages the holding frame so as to restrict the movement of the holding frame only in the rotation direction about the optical axis;
Have
The relative position of the holding frame and the support member in the optical axis direction is adjusted by moving the first engagement member along the guide groove with the relative rotation of the holding frame and the support member. And adjusting the relative fall of the holding frame and the support member by rotating the first engagement member,
A lens barrel, wherein the holding frame is fixed to the support member by fixing the second engagement member to the support member. The holding frame is provided with a recess for fitting the second engagement member,
The second engagement member is restricted from moving in the rotational direction around the optical axis by the recess,
2. The lens barrel according to claim 1, wherein a size of the concave portion in an optical axis direction and a radial direction is larger than a size of the second engaging member in the optical axis direction and the radial direction. 3. The lens barrel according to claim 1, wherein the second engagement member is a nut, and is fixed so as to sandwich the support member together with a screw. The lens barrel according to claim 1, wherein the first engaging member is an eccentric roller. An interchangeable lens comprising the lens barrel according to claim 1. The interchangeable lens according to claim 5;
And a camera body to which the interchangeable lens can be attached.

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