JP2013125227A - Lens barrel and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel that can be downsized by reducing a space required for positioning a lens frame with a simple structure.SOLUTION: A lens barrel is provided to position an adjustment lens with respect to other lenses in an optical axis direction. The lens barrel includes a lens frame 1 for holding an adjustment lens, and a base frame 2 for adjustably holding the lens frame 1. The lens frame 1 includes a first adjustment step surface 11 and a second adjustment step surface each having a plurality of adjustment surfaces different in height and adjacent to each other in a rotation direction of the lens frame 1. The second adjustment step surface 12 is provided at a phase position rotated by 180 degrees with respect to a position where the first adjustment step surface 11 is provided. The base frame 2 includes holding surfaces each of which is brought into contact with the first adjustment step surface 11 or the second adjustment step surface 12. The adjustment lens includes cutouts, and the holding surfaces are arranged so that at least a part of the holding surfaces overlaps with any of the cutouts provided in the adjustment lens when viewed from the optical axis direction.

Description

  The present invention relates to a lens barrel and an imaging apparatus.

  In recent years, imaging devices such as cameras and video cameras have been increasing in magnification and size. In order to realize a high magnification of the imaging apparatus, the diameter of the lens itself included in the imaging apparatus is increasing. In addition, as the size of the image pickup apparatus advances, the lens position accuracy has been improved in order to satisfy the optical performance.

  The optical performance of the image pickup apparatus cannot be satisfied only by improving the accuracy and lens performance of the components constituting the lens barrel, and therefore it is necessary to adjust the lens position according to the individual lens barrel. For example, eccentric adjustment that aligns the lens axis, inclination adjustment that adjusts the inclination of the lens axis, or tracking adjustment that adjusts the distance between adjacent lenses has been proposed.

  Patent Document 1 discloses a method for adjusting the movement of a lens in a lens barrel having a lens frame in which three sets of adjustment step surfaces are formed stepwise in the circumferential direction. In this movement adjustment method, the height of the optical axis direction is adjusted by changing the adjustment step surface to be brought into contact with the holding member by rotating the lens frame.

JP 2009-237409 A

  The lens frame disclosed in Patent Document 1 is provided with a through hole for inserting a screw on the outer peripheral side of the lens. Then, the lens frame is rotated in accordance with the adjustment position of the lens, and the lens frame is fixed by fixing screws at three positions at that position.

  However, in order to realize the lens movement adjustment method disclosed in Patent Document 1, it is necessary to provide screw holes for fixing the lens frame by the rotation angle necessary for the adjustment. Specifically, it is necessary to provide screw holes only at 120 degrees × 3 locations = 360 degrees. Therefore, in order to realize this lens movement adjustment method, it is necessary to secure a space on the outer periphery of the lens.

  It is also conceivable to fix the lens frame by bonding or the like instead of screws. However, even when the lens frame is fixed by bonding or the like, it is necessary to secure a space for bonding or the like only in a range in which the lens frame rotates. If you try to narrow the range in which the lens frame rotates in order to narrow the space for screw holes or space for bonding, etc., this will lead to a reduction in the number of adjustment step surfaces and lens adjustment The problem becomes insufficient.

  In other words, the conventional lens barrel requires a large space for fixing the lens frame on the outer periphery of the lens, and it is difficult to secure a space for arranging components other than the lens frame, such as a barrier unit. It was. In addition, it is necessary to increase the lens barrel diameter by the amount of components other than fixing the lens frame.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lens barrel that has a simple structure and can be reduced in size while suppressing a space required for adjusting the position of a lens frame.

  A lens barrel according to an embodiment of the present invention is a lens barrel that adjusts the position of an adjustment lens included in a plurality of lenses included in an optical system in the optical axis direction with respect to another lens. The lens barrel includes a first holding frame that holds the adjustment lens and a second holding frame that holds the first holding frame in an adjustable manner. One of the first and second holding frames has a first adjustment surface group having a plurality of adjustment surfaces provided with different heights adjacent to the rotation direction of the holding frame. And an adjustment surface group different from the first adjustment surface group, and a second adjustment surface group composed of a plurality of adjustment surfaces provided at different heights adjacent to the rotation direction. . The second adjustment surface group is provided at a 180-degree rotational phase position from the position where the first adjustment surface group is provided. Of the first and second holding frames, the holding frame different from the holding frame provided with the first adjusting surface group and the second adjusting surface group includes the first adjusting surface group or the first adjusting frame group. The support part which contact | abuts 2 adjustment surface groups is provided. The adjustment lens is provided with a notch, and at least a part of the support is disposed at a position overlapping the notch provided in the adjustment lens when viewed from the optical axis direction. The

  According to the lens barrel of the present invention, a space necessary for adjusting the position of the lens frame can be suppressed with a simple structure. This makes it possible to reduce the size of the lens barrel.

It is a figure which shows an example of the disassembled perspective view of the lens-barrel of this embodiment. It is a figure which shows an example of the lens frame holding an adjustment lens. It is a figure explaining the relationship between a base frame and an adjustment lens. It is a figure which shows an example of the cross section of a lens frame and a base frame. It is a figure (1) explaining the change of the contact state of the adjustment surface and support surface at the time of tracking adjustment. It is a figure (2) explaining the change of the contact state of the adjustment surface and support surface at the time of tracking adjustment.

  Hereinafter, the lens barrel of this embodiment will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of an exploded perspective view of a lens barrel of the present embodiment. FIG. 2 is a diagram illustrating an example of a lens frame that holds the adjustment lens. FIG. 3 is a diagram illustrating the relationship between the base frame and the adjustment lens. FIG. 4 is a diagram illustrating an example of a cross section of the lens frame and the base frame. The imaging apparatus of this embodiment includes a lens barrel of this embodiment described below.

  The lens barrel of the present embodiment can be obtained by moving the adjustment lens in the optical axis direction or tilting the optical axis of the adjustment lens with respect to the reference axis with respect to other lens groups (not shown) constituting the barrel. Adjust the position to satisfy the optical performance. That is, the lens barrel has a position adjustment structure in which the adjustment lens included in the plurality of lenses of the optical system can be adjusted with respect to other lenses in the optical axis direction. In the following description, adjustment by movement in the optical axis direction is described as tracking adjustment, and adjustment for tilting the optical axis of the adjustment lens with respect to the reference axis is described as tilt adjustment.

  FIG. 3 is a diagram illustrating a relationship between the base frame and the adjustment lens. L1 is an adjustment lens whose position is adjusted. As shown in FIG. 3, the adjustment lens L1 has a shape in which two sides L1a and L1b in the vertical direction and two sides L1c and L1d in the left and right direction are cut from a circular shape of φD. The lens frame 1 holds the adjustment lens L1 (a first holding frame).

  As shown in FIG. 2A, the lens frame 1 includes fixed arm portions 1a, 1b, 1c, and 1d, which are four fixing members extending in the radial direction, and has a 180-degree rotationally symmetric shape. The fixed arm portion is an arm for applying and fixing an adhesive to the fixed arm portions 1a, 1b, 1c, and 1d at a position where the adjustment lens is adjusted.

  Further, as shown in FIG. 2B, the first adjustment is made on the outer peripheral surface of the portion (holding portion) where the adjustment lens L1 is held in a state where the lens frame 1 holds the adjustment lens L1. A step surface 11 and a second adjustment step surface 12 are provided. The first adjustment step surface 11 functions as a first adjustment surface group having a plurality of adjustment surfaces provided with different heights adjacent to each other in the rotational direction of the lens frame 1. In this example, the first adjustment step surface 11 has three adjustment surfaces 1e, 1f, and 1g. The respective adjustment surfaces of the first adjustment step surface 11 are arranged at different heights in accordance with the tracking adjustment width.

  The second adjustment step surface 12 functions as a second adjustment surface group having a plurality of adjustment surfaces provided with different heights adjacent to the rotation direction of the lens frame 1. In this example, the second adjustment step surface 12 has three adjustment surfaces 1h, 1i, and 1j. The respective adjustment surfaces of the second adjustment step surface 12 are arranged with different heights according to the tracking adjustment width different from the tracking adjustment width of the first adjustment step surface 11. The second adjustment step surface 12 is provided at a 180 ° rotation phase position from the position where the first adjustment step surface 11 is provided.

  Further, the lens frame 1 has adhesive grooves 1k and 11 (see FIGS. 2A, 5 and 6) provided at positions overlapping with any one of the lens cut portions L1a, L1b, L1c and L1d when viewed from the optical axis direction. Is provided.

  The base frame 2 holds the lens frame 1 so as to be adjustable (a second holding frame). When the base frame 2 is connected to a lens group (not shown) other than the adjustment lens L1, the lens barrel of the present embodiment is configured as a barrel composed of a plurality of lens groups.

  Three support surfaces 2a, 2b, and 2c are provided at 120 degrees equally on the inner periphery of the base frame 2. The support surfaces 2 a to 2 c function as a support portion that supports the lens frame 1 by contacting the first adjustment step surface 11 or the second adjustment step surface 12 of the lens frame 1.

  As shown in FIG. 3, at least a part of the support surfaces 2a, 2b, and 2c is provided at a position that overlaps one of the lens cut portions L1a, L1b, L1c, and L1d of the adjustment lens L1 when viewed from the optical axis direction. ing. This eliminates the need to provide the support surfaces 2a, 2b, and 2c outside the outer diameter φD of the adjustment lens L1, thereby reducing the size of the lens barrel.

  Further, the base frame 2 includes fixed convex portions 2j and 2k that function as first fixing members. The fixed convex portions 2j and 2k are provided at positions overlapping the lens cut portions L1a and L1b of the adjustment lens L1 when viewed from the optical axis direction. The lens frame 1 and the base frame 2 are fixed by applying an adhesive between the fixed convex portions 2j and 2k and the adhesive grooves 1k and 1l provided in the lens frame 1. Note that a fixing convex portion for fixing the lens frame 1 and the base frame 2 may be provided on the lens frame 1. When the fixed convex portion is provided in the lens frame 1, the above-described adhesive grooves 1 k and 1 l are provided not in the lens frame 1 but in the base frame 2. That is, an adhesive groove is provided in a holding frame that is different from the holding frame provided with the first fixing member among the first holding frame and the second holding frame.

  The base frame 2 includes screw seats 2h and 2i that function as second fixing members that fix the cover member 3. At least a part of the screw seats 2h and 2i is provided at a position overlapping the lens cut portions L1a and L1b of the adjustment lens L1 when viewed from the optical axis direction. A screw seat may be provided on the cover member 3.

  In the present embodiment, the lens frame 1, that is, the first holding frame includes the first adjustment step surface and the second adjustment step surface, but the base frame 2, that is, the second holding frame, instead of the lens frame 1, is the first. An adjustment step surface and a second adjustment step surface may be provided. In other words, one of the first and second holding frames includes a first adjustment surface group and a second adjustment surface group.

  The cover member 3 has an opening provided at the center so as not to block the light beam that passes through the lens barrel and reaches the image sensor. The cover member 3 is provided on the subject side of the lens frame 1.

  The cover member 3 is fixed to the base frame by screws 4 in the screw fastening holes 3b and 3c, and by hook-shaped locking portions 3g and 3h extending in the optical axis direction as shown in FIG. 2 is fixed. The screw fastening holes 3b and 3c and the locking portions 3g and 3h are provided at positions overlapping with any one of the lens cut portions (L1a, L1b, L1c, and L1d) of the adjustment lens L1 as viewed from the optical axis direction. As a result, the screw fastening holes 3b and 3c and the locking portions 3g and 3h do not have to be provided on the outer peripheral portion of the lens φD, and the size of the lens barrel can be reduced.

  FIG. 4A is an example of a cross-sectional view taken along line AA in FIG. The cover member 3 is configured such that accessories (for example, a lens hood, a lens filter, a lens cap, a converter lens, and the like) that can be attached to the lens barrel can be attached using the outer peripheral rib 3d and the ear portions 3e and 3f. Yes. When accessories or the like are attached by the user of the camera (imaging device), a large force is applied to the cover member 3, so screws are fastened to fix the base frame 2, and parts can be easily detached or broken. Is prevented.

  FIG. 4B is a diagram illustrating an example of a cross section of the lens frame and the base frame. With reference to FIG. 4B, the contact between the first adjustment step surface 11 or the second adjustment step surface 12 of the lens frame 1 and the support surfaces 2 a to 2 c of the base frame 2 will be described. FIG. 4B shows a state where the first adjustment surface 1f and the support surface 2a are in contact with each other.

  By rotating the lens frame 1 by the widths of the three adjustment surfaces 1e, 1f, and 1g of the first adjustment step surface 11, the position of contact with the support surfaces 2a, 2b, and 2c of the base frame 2 sequentially changes. . As a result, the height of the adjustment lens L1 in the optical axis direction is changed, and tracking adjustment is performed.

  Further, the adjustment surfaces 1e, 1f, and 1g are formed in an R surface shape from a predetermined reference position. Accordingly, when the adjustment surface is brought into contact with the support surfaces 2a, 2b, and 2c of the base frame 2 formed of a flat inclined surface, the optical axis O can be inclined on R around a predetermined reference position. As a result, tilt adjustment is possible. In order to stably support the lens frame 1, the support surfaces are provided at three positions equal to 120 degrees, but need not necessarily be equal to 120 degrees.

  In this example, the base frame 2 has a support surface. However, the base frame 2 may include a first adjustment step surface and a second adjustment step surface, and the lens frame 1 may include a support surface. That is, of the first and second holding frames, the holding frame different from the holding frame provided with the first adjustment step surface and the second adjustment step surface is the first adjustment step surface or the second adjustment step surface. And a support portion that abuts.

  5 and 6 are diagrams for explaining changes in the contact state between the adjustment surface and the support surface during tracking adjustment. FIG. 5A shows a state in which the adjustment surface 1e and the support surfaces 2a, 2b, and 2c are in contact with each other. FIG. 5B shows a state where the adjustment surface 1f and the support surfaces 2a, 2b, and 2c are in contact with each other. FIG. 6 shows a state in which the adjustment surface 1g and the support surfaces 2a, 2b, and 2c are in contact with each other.

  The lens frame 1 that has been subjected to tracking adjustment and tilt adjustment is fixed to the base frame 2 by adhesion. Here, if the adhesive is set to be applied in the range of 2d, 2e, 2f, and 2g shown in FIGS. 5 and 6, the fixed arm portion is surely secured in any state shown in FIGS. An adhesive is applied on 1a, 1b, 1c, 1d. Thereby, the lens frame 1 can be reliably fixed to the base frame 2. That is, the lens frame 1 and the base frame 2 are fixed by a fixed arm portion to which an adhesive is applied.

  The adhesive application ranges 2d, 2e, and 2f are determined by the width of the fixed arm and the amount of rotation of the lens frame 1 used for tracking adjustment. That is, if the rotation amount of the lens frame 1 for tracking adjustment is reduced, the application range of the adhesive can be narrowed accordingly. In the present embodiment, adhesive grooves 1k and 1l are further provided in the lens frame 1 using portions corresponding to the L1a and L1b portions cut from the arc of the adjustment lens L1, and the fixed convex portion 2j of the base frame 2 is provided. , 2k.

  The application range of the adhesive to the fixed arm portion is a range determined based on the width of the fixed arm portion in the rotation direction and the rotation amount of the lens frame 1 necessary for tracking adjustment. If the rotation amount of the lens frame 1 for tracking adjustment is reduced, the application range of the adhesive can be narrowed accordingly.

  The lens frame 1 is provided with a second adjustment step surface 12, and the second adjustment step surface 12 and the support surfaces 2a, 2b, and 2c can be brought into contact with each other. As described above, the second adjustment step surface 12 is provided at the 180-degree rotational phase position of the first adjustment step surface. That is, when the lens frame 1 is rotated 180 degrees and placed on the base frame 2 from the state in which the first adjustment step surface 11 is in contact with the support surface, the second adjustment step surface 12 is in contact with the support surface.

  That is, the support surface provided in the holding frame different from the holding frame provided with the first adjustment step surface and the second adjustment step surface comes into contact with the second adjustment step surface in the following cases. In other words, the support surface is configured such that the holding frame provided with the first adjustment step surface and the second adjustment step surface moves the support surface at a rotational phase position of 180 degrees from the position where the support surface contacts the first adjustment step surface. When placed on the holding frame provided, it comes into contact with the second adjustment step surface.

  Since the second adjustment step surface 12 is provided with a height different from that of the first adjustment step surface 11, tracking adjustment can be performed at a height position that cannot be adjusted by the height of the first adjustment step surface. It becomes possible.

  Further, the fixed arm portions 1a, 1b, 1c, and 1d of the lens frame 1 have a shape made to be 180 degrees rotationally symmetric. Specifically, the fixed arm portion 1a and the fixed arm portion 1c are provided at a 180 ° rotation phase position. The fixed arm portion 1b and the fixed arm portion 1d are provided at a 180 ° rotation phase position. Accordingly, even when tracking adjustment is performed using the second adjustment step surface 12, the adhesive application range for fixing the lens frame 1 is set to 2d, 2e, 2f, and 2g shown in FIGS. Thus, the lens frame 1 can be securely fixed to the base frame 2.

  In the configuration in which the adjustment surface is provided on the base frame 2 instead of the lens frame 1 and the support surface is provided on the lens frame 1, the base frame 2 may be provided with a fixed arm portion. That is, of the first and second holding frames, the holding frame is provided on the outer periphery of the holding frame provided with the first adjustment step surface and the second adjustment step surface with respect to the holding frame having the support surface. A plurality of fixed arm portions to be fixed are provided. Each fixed arm portion included in the plurality of fixed arm portions is provided at a 180 ° rotation phase position with respect to the corresponding fixed arm portion.

  According to the above configuration, the lens frame 1 can be adjusted within the first adjustment step surface by rotating the lens frame 1, and the lens frame 1 can be further rotated 180 degrees with respect to the base frame 2 in the second adjustment step surface. But it is adjustable. In other words, the position adjustment mechanism can be adjusted with the number of adjustment steps corresponding to two of the first adjustment step surface and the second adjustment step surface, with only the lens frame rotation angle corresponding to the number of steps where the first adjustment step surface is installed. .

  Specifically, the height of the first adjustment step surface 11 can be adjusted by three steps, and the second adjustment step surface 12 can be adjusted by three steps at a different height. That is, according to the lens barrel of the present embodiment, height adjustment for six steps can be performed while suppressing the rotation angle of the lens frame 1 rotated for adjustment.

  When the rotation angle of the lens frame 1 is small, the rotation range of the fixed arm portions 1a, 1b, 1c, and 1d for fixing the lens frame 1 is reduced. As a result, the ranges 2d, 2e, 2f and 2g where the adhesive is applied are narrowed. If the adhesive application range can be made small, the space on the outer periphery of the adjustment lens L1 can be used for components other than the adhesive.

  According to the lens barrel of the present embodiment, the position of the lens barrel 1 can be adjusted by rotating the lens frame 1, and the position of the lens barrel can be adjusted by rotating the lens frame by half the number of adjustable stages. Can do.

  Furthermore, since the lens barrel of the present embodiment can reduce the amount of rotation of the adjustment lens L1, the effects described below can be achieved. A range A shown in FIGS. 5 and 6 is a range that does not block the light flux to the image sensor (effective light flux range). The position of the adjustment lens is adjusted, and the adjustment lens is cut (cut portions L1a, L1b, L1c, L1d) so as not to block the range A at any position where the lens frame is rotated.

  The larger the amount rotated for adjusting the lens frame, the smaller the area that can be cut from the circular shape of φD. If the cuttable range is reduced, it becomes difficult to arrange a member for adjusting the lens and a member for attaching accessories in the space created by the cutting. Since the lens barrel of the present embodiment can reduce the rotation amount of the adjustment lens L1, it has a simple configuration so as to ensure a sufficient adjustment amount of the adjustment lens L1 and from a circular shape so as not to block the effective light beam range. Enables lens cutting. Thereby, the space obtained by lens cutting can be used effectively.

  Further, the reason that the effective light beam range A has a substantially rectangular shape close to the shape of the image sensor is that the lens is on the subject side farthest from the image sensor. In the lens barrel of the present embodiment, the range that can be cut out is increased by providing a cutout portion from a circular shape in the lens closest to the subject. Thereby, a member for adjusting the lens and a member for attaching the accessory can be arranged.

  In other words, according to the lens barrel of the present embodiment, the lens mirror is configured so as to be able to attach a member for adjusting the position of the lens and an accessory (for example, a hood, a filter, a converter lens) at the tip. The diameter of the tube can be reduced.

  The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the scope of the present invention. For example, the number of adjustment surfaces of the first adjustment step surface 11 and the second adjustment step surface 12 may be different. May be the same.

  In the above-described example, the adjustment lens L1 has a configuration capable of tracking adjustment and tilt adjustment, and the first adjustment step surface has an R shape. However, the adjustment lens L1 may be capable of only tracking adjustment. And the 1st adjustment step surface may be comprised by the flat surface.

  In the above-described example, the cutout portion from the circular shape of the adjustment lens L1 is two sides in the vertical direction and two sides in the left-right direction, but the place to be cut is not limited to this. It may be cut in any shape as long as it does not block the effective light beam area.

1 Lens frame 2 Base frame L1 Adjustment lens

Claims (6)

A lens barrel that adjusts the position of an adjustment lens included in a plurality of lenses of an optical system in the optical axis direction with respect to another lens,
A first holding frame for holding the adjustment lens;
A second holding frame that adjustably holds the first holding frame;
One of the first and second holding frames has a first adjustment surface group having a plurality of adjustment surfaces provided with different heights adjacent to the rotation direction of the holding frame. And an adjustment surface group different from the first adjustment surface group, and a second adjustment surface group consisting of a plurality of adjustment surfaces provided at different heights adjacent to each other in the rotational direction. ,
The second adjustment surface group is provided at a 180-degree rotational phase position from the position where the first adjustment surface group is provided,
Of the first and second holding frames, the holding frame different from the holding frame provided with the first adjusting surface group and the second adjusting surface group includes the first adjusting surface group or the first adjusting frame group. (2) A support portion that comes into contact with the adjustment surface group is provided.
The adjustment lens is provided with a notch,
At least a part of the support portion is disposed at a position overlapping the notch portion provided in the adjustment lens when viewed from the optical axis direction. A first fixing member for fixing the first holding frame and the second holding frame to the first holding frame or the second holding frame;
The at least part of the first fixing member is disposed at a position overlapping the notch portion provided in the adjustment lens when viewed from the optical axis direction. Lens barrel. Of the first holding frame and the second holding frame, an adhesive groove is provided in a holding frame different from the holding frame provided with the first fixing member,
The first holding frame and the second holding frame are fixed by applying an adhesive between the first fixing member and the adhesive groove,
The lens barrel according to claim 2, wherein the adhesive groove is disposed at a position overlapping the notch portion provided in the adjustment lens when viewed from the optical axis direction. A cover member fixed to the second holding frame;
The second holding frame or the cover member is provided with a second fixing member for fixing the second holding frame and the cover member,
The at least part of the second fixing member is disposed at a position overlapping the notch portion provided in the adjustment lens when viewed from the optical axis direction. The lens barrel according to any one of the above. Of the first and second holding frames, the support portion provided in a holding frame different from the holding frame provided with the first adjustment surface group and the second adjustment surface group is the first adjustment surface. A holding frame provided with a group and the second adjustment surface group is placed on the holding frame provided with the support portion at a rotation phase position of 180 degrees from a position where the support portion comes into contact with the first adjustment surface group. The lens barrel according to claim 1, wherein the lens barrel comes into contact with the second adjustment surface group. An imaging apparatus comprising the lens barrel according to claim 1.

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