JP2014038213A - Lens device and imaging device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens device in which a light shielding member for shielding a notch part provided on a movable frame for a lens group for interference prevention is rotatably fitted to the movable frame so that unnecessary light from the notch part is shielded without causing the light shielding member to be another moving group than the movable frame.SOLUTION: A lens device has a first cam follower which holds an optical member, has a notch part at a part of an outer circumferential part, engages with a first cam groove formed on a cam barrel, and has a first movable frame which moves in an optical axis direction along the first cam groove, and a light shielding member, held at the first movable frame rotatably around the optical axis, for covering the notch part at a prescribed rotational position around the optical axis. A second cam follower disposed on the light shielding member engages with a second cam groove formed on the cam barrel, so that a state that the light shielding member covers the notch part changes in accordance with a position of the first movable frame in the optical axis direction.

Description

  The present invention relates to a lens apparatus, and more particularly to light shielding in a lens barrel of a lens apparatus, and also relates to an imaging apparatus having the lens apparatus.

  In a zoom lens apparatus that includes a variable power lens that is a first lens and a correction lens that is a second lens, it is necessary to set the moving distance of the variable power lens long in order to achieve higher magnification. However, in order to reduce the optical axis length of the lens while reducing the optical axis length while ensuring the photographing magnification, depending on the moving range of the variable power lens, the moving frame that supports the first lens and the second lens are supported. When the moving frames approach, the moving frames may interfere with each other. For this reason, the lens moving frame is provided with a notch in a portion where the lens moving frames interfere with each other, and the notch is configured so as to avoid contact with the moving frame on the other side. Interference is prevented. However, when the lens moving frames are separated from each other, unnecessary light (harmful light) is incident from the cutout portion of the lens moving frame, and the image quality is degraded. Therefore, when the lens moving frames are separated from each other, it is necessary to shield the cutout portion of the moving frame.

  In Patent Documents 1 and 2, a light shielding member and a light shielding cylinder are provided as a moving group different from the lens moving frame in front and outside of the lens moving frame of the lens group, and they are moved according to zooming, and a cutout portion is provided. Proposals have been made to shield unwanted light from

Japanese Patent Laid-Open No. 10-268174 JP-A-9-33781

  However, in the above-mentioned patent document, since the light shielding member and the light shielding cylinder are provided in front and outside of the lens moving frame as a moving group different from the lens moving frame, a space for arranging these parts is required. Furthermore, the structure becomes complicated.

  Therefore, an object of the present invention is to provide a lens device that shields unnecessary light from a notch without using a light blocking member as a moving group different from the lens moving frame.

  In order to achieve the above object, a lens device of the present invention holds a first optical member, has a notch in a part of an outer peripheral portion, and is engaged with a first cam groove formed in a cam cylinder. A first moving frame that has a first cam follower that moves in the optical axis direction along the first cam groove, and is held by the first moving frame so as to be rotatable about the optical axis. A light shielding member that covers the cutout portion at a predetermined rotational position around the optical axis, and a second cam follower disposed on the light shielding member is formed in the cam cylinder. The state in which the light shielding member covers the notch portion changes according to the position of the first moving frame in the optical axis direction.

  According to the present invention, there is provided a lens device in which the light shielding member shields and opens the cutout portion of the moving frame in accordance with the position of the moving frame without using the light shielding member as a moving group different from the lens moving frame. can do.

Sectional view when each moving frame of the lens device is positioned at the wide-angle end A perspective view when each moving frame of the lens device is positioned at the wide-angle end Sectional view when each moving frame of the lens unit is located at the telephoto end A perspective view when each moving frame of the lens device is positioned at the telephoto end Plan view of the light shielding member provided on the moving frame Cam groove provided on the cam cylinder

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2 show a cross-sectional view and a perspective view when the lens apparatus 1 in the present embodiment is positioned at the wide-angle end. 3 and 4 show a cross-sectional view and a perspective view when the lens apparatus 1 is located at the telephoto end. FIG. 5 is a plan view of the light shielding member 14 provided on the moving frame 13a. 6 shows the moving frames 13a and 13b provided on the cam cylinder 4 and the cam grooves 7a, 7b and 7c of the light shielding member 14. The arrow 50a is the subject side, the arrow 50b is the image sensor side, and the arrow 60a is the wide angle. The end side, arrow 60b indicates the telephoto end side.

  The mechanism of the zoom unit will be described with reference to FIG. The lens apparatus 1 has a plurality of lens groups, and a focus lens group 10 and a relay lens group (not shown) are arranged before and after the zoom unit. The focus lens group 10 is provided movably along the optical axis direction 30 and is driven by a driving unit (not shown). Thereby, focus adjustment is performed. The lens group 11 (first optical member) is supported by a moving frame 13a (first moving frame), and the lens group 12 (second optical member) is supported by a moving frame 13b (second moving frame). Yes. The cam cylinder 4 is formed with cam grooves 7 a, 7 b, 7 c describing the trajectories of the moving frames 13 a, 13 b and the light shielding member 14 in the optical axis direction 30. It is arranged so as to be rotatable around the direction 30. The fixed cylinder 3 is provided with rectilinear grooves 6a and 6b (first cam groove and third cam groove) that allow the movable frames 13a and 13b to slide along the optical axis direction 30. Cam frames 5a and 5b (first cam followers and third cams) that engage with the straight grooves 6a and 6b provided in the fixed cylinder 3 and the cam grooves 7a and 7b provided in the cam cylinder 4 are provided on the moving frames 13a and 13b. A plurality of cam followers) are formed around the optical axis 30. The zoom ring 2 is rotatable about the optical axis 30 and is fitted to the fixed cylinder 3 and is connected to the cam cylinder 4 via a connecting pin 9. When the zoom ring 2 is rotated, the cam cylinder 4 is also rotated, and the moving frames 13a and 13b are moved in a predetermined direction in the optical axis direction 30 by the rectilinear guide action by the cam grooves 7a and 7b and the rectilinear grooves 6a and 6b. Move along the trajectory. As described above, the moving frames 13a and 13b move along the optical axis direction 30 to change the lens interval, thereby changing the magnification.

  Next, the shielding of the notch 16a of the moving frame 13a will be described with reference to FIGS. The moving frame 13a has a predetermined outer peripheral portion of the moving frame 13a that interferes with a part of the moving frame 13b in order to prevent interference between the moving frames when the moving frames (13a, 13b) approach during zooming. There are three notches 16a in the place, and the structure does not interfere with the moving frame 13b. At the wide-angle end shown in FIG. 1, the light beam 20 reaching the notch 16a passes through the notch 16a like the light beam 21, passes through the lens group 12, and forms an image on the image pickup device. It may be harmful light that causes deterioration. Therefore, at the wide-angle end, as shown in FIG. 1, the light reaching the notch 16a is blocked by covering the notch 16a with the light shielding member 14 in the optical axis direction so as to shield the notch 16a. Prevent it from passing through and causing harmful light. When the moving frames 13a and 13b such as the telephoto end approach, the light shielding member 14 rotates around the optical axis direction 30 in order to prevent the interference between the light shielding member 14 and the moving frame 13b, and the notch 16a is moved. Open. However, since the moving frame 13b is inserted into the cutout portion 16a, the light reaching the cutout portion 16a is blocked without passing through the cutout portion 16a, and the image quality is not deteriorated.

  Next, the operation of the light shielding member 14 will be described. As shown in FIG. 5, the light shielding member 14 includes a notch 16b for preventing interference with the moving frame 13b, an opening 17 that is rotatably fitted and held in the moving frame 13a, and the cam cylinder 4. And an engaging portion 8 (second cam follower) that engages with a cam groove 7c (second cam groove). The light shielding member 14 is fitted into the moving frame 13 a after the opening 17 is rotatably fitted to the moving frame 13 a and the engaging portion 8 is engaged with the cam groove 7 c provided in the cam cylinder 4. The retaining ring 15 is retained by the retaining ring 15. In FIG. 2 showing the state at the wide-angle end, the light shielding member 14 is arranged so as to hide the notch 16a of the moving frame 13a. As a result, the light beam 20 that causes the deterioration of the image quality of the light that has passed through the focus lens group 10 is blocked by the light shielding member 14 and does not enter the lens group 12, so that the image quality is not deteriorated. Here, when the zoom position moves from the wide-angle side to the telephoto side, the zoom ring 2 rotates around the optical axis direction 30 and the cam cylinder 4 connected by the connecting pin 9 also rotates around the optical axis direction 30. Thereby, the moving frame 13a and the light shielding member 14 cooperate integrally in the optical axis direction 30 along the locus of the cam grooves 7a and 7c provided in the cam cylinder 4. In the range of 70 a of the cam grooves 7 a and 7 c shown in FIG. 6, the moving frame 13 a and the light shielding member 14 move along the optical axis direction 30 in the same phase. At that time, the light shielding member 14 shields the cutout portion 16a of the moving frame 13a (covers in the optical axis direction). In the range of 70b, the locus of the cam grooves 7a and 7c changes, so that the light shielding member 14 rotates relative to the moving frame 13a in the direction of the arrow 40 shown in FIG. The notch 16a is opened before the frame 13b interferes. In the range of 70c, the moving frame 13a and the light shielding member 14 move in the same phase along the optical axis direction 30 as in the case of 70a, and the moving frame 13b is inserted into the cutout portion 16a. That is, the light shielding member 14 covers and shields the notch 16a of the moving frame 13a in the optical axis direction at a predetermined rotation position with respect to the moving frame 13a.

  As described above, according to the present embodiment, the cutout portion of the moving frame can be blocked only at a necessary zoom position without arranging the light shielding member as a moving group different from the moving frame. Further, since the moving frame 13b that supports the light shielding member 14 and the second lens 12 can be changed in the shielding / opening state without contact, harmful light from the cutout portion is generated without causing a collision sound or vibration. Can be prevented. Further, since the light shielding member is moved by the cam groove provided in the common cam cylinder, the light shielding member moving mechanism can be configured without significantly increasing the number of parts, and the cost can be reduced.

  In the above-described embodiments, the lens group configuring the zoom unit has been illustrated and described, but the present invention is not limited to this. The configuration of the present invention can also be applied to lens groups other than the group constituting the zoom unit, and other optical elements such as a diaphragm, preventing the incidence of harmful light to the image sensor and enjoying the effects of the present invention. I can do it. Further, the image pickup apparatus having the lens device of the present invention and having an image sensor that receives subject light from the lens device of the present invention prevents harmful light from being incident on the image sensor, and deterioration of image quality due to the harmful light. It is possible to provide an imaging device that does not have any.

  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.

1: Lens device 4: Cam cylinders 5a to 5b: Cam followers 7a to 7c: Cam groove 8: Engaging portions 13a to 13b: Moving frame 14: Light shielding members 16a to 16b: Notch portion 17: Opening portion

Claims (4)

The first cam has a first cam follower that holds the first optical member, has a notch in a part of the outer periphery, and engages with a first cam groove formed in the cam cylinder. A first moving frame that moves in the optical axis direction along the groove;
A light-shielding member that is held by the first moving frame so as to be rotatable around an optical axis and covers the notch at a predetermined rotational position around the optical axis;
Have
A second cam follower disposed on the light shielding member engages with a second cam groove formed in the cam cylinder, and the light shielding member is moved according to the position of the first moving frame in the optical axis direction. The state of covering the notch changes,
A lens device. A second cam member that holds the second optical member and engages with a third cam groove formed in the cam cylinder and moves in the optical axis direction along the third cam groove. With a moving frame
When the first moving frame and the second moving frame come closer than a predetermined distance, the second cam groove is formed so that the light shielding member opens the notch, and the first moving frame is formed. A part of the second moving frame is inserted into the cutout portion of
The lens device according to claim 1.   The lens device according to claim 1, wherein the first moving frame and the second moving frame move with zooming.   An imaging apparatus comprising: the lens apparatus according to claim 1; and an imaging element that receives subject light from the lens apparatus.

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