JP7292976B2 - Lens device and imaging device - Google Patents

Description

The present invention relates to a lens device and an imaging device.

2. Description of the Related Art A lens device is known that performs focusing and variable magnification by connecting an annular operating member that can rotate about an optical axis and a cam mechanism that moves an optical element in the optical axis direction via a connecting member. In the lens device, in order to smoothly rotate the cam cylinder of the cam mechanism about the optical axis, it is common to provide a minute gap in the sliding portion of the cam cylinder. However, in recent years, along with an increase in the number of pixels of an image sensor, the positional accuracy of the optical elements required for the lens apparatus is increasing. Therefore, in the structure as described above, when the operation member is reversed, the position of the optical element in the optical axis direction may fluctuate within the range of play of the cam barrel, which may cause, for example, defocusing. . For this reason, in recent lens devices, it is required that the play in the optical axis direction of the cam cylinder that drives the optical element in the optical axis direction is as close to zero as possible.

In response to such structural requirements, Japanese Patent Laid-Open No. 2002-100000 discloses a lens device that reduces backlash of a cam barrel by urging an elastic member disposed in a recess provided on the end face of the cam barrel in the optical axis direction. is disclosed. Further, Patent Document 2 discloses a lens device in which each end surface of a cam barrel is biased in the optical axis direction by an elastic member via a row of balls.

Japanese Patent No. 4045676 JP 2017-49280 A

However, in the lens device of Patent Document 1, a frictional force proportional to the urging force is generated on the end face opposite to the end face on which the elastic member is arranged in the optical axis direction. can be Moreover, although the lens device of Patent Document 2 can prevent the rotational torque of the cam barrel from becoming excessively large due to the force that biases the cam barrel, the number of parts is large, and the lens device may become large. SUMMARY OF THE INVENTION It is an object of the present invention to provide, for example, a lens apparatus that is advantageous in reducing variations in the position of a cam barrel in the direction of the optical axis.

In order to achieve the above object, the lens apparatus of the present invention includes an optical member, a cam barrel that rotates around the optical axis to move the optical member in the direction of the optical axis, and a cam barrel that rotates around the optical axis. an operating member that can be rotated to rotate the cam barrel ; and a connecting member that connects the cam barrel and the operating member with respect to rotation about the optical axis, the connecting member comprising: It is elastically deformable in a radial direction about the optical axis, and includes a first portion fixed to the cam cylinder and a second portion fixed to the operation member, wherein the first portion and the front The second portion is characterized by being engaged with each other so as to suppress variation in relative position in the direction of the optical axis .

According to the present invention, for example, it is possible to provide a lens device that is advantageous in reducing variations in the position of the cam cylinder in the direction of the optical axis.

Side cross-sectional view of essential parts of the lens device Longitudinal cross-sectional view in the AA cross section of FIG. Principal part exploded perspective view of the lens device Partially enlarged view of the connecting part

Preferred embodiments of the invention will be described in detail below on the basis of the embodiments shown in FIGS. 1 to 4. FIG.

FIG. 1 is a side cross-sectional view of essential parts of a lens device 1 in an embodiment of a lens device to which the present invention is applied. In the drawing, the left side is the object side, and the right side is the image plane side. 2 is a longitudinal sectional view of the lens device taken along the line AA shown in FIG. 1. FIG. Further, FIG. 3 shows an exploded perspective view of the main part of the lens device 1. As shown in FIG.

The fixed barrel 9 is connected to a connecting portion with an imaging device (not shown) to which the lens device 1 is attached. The lens device 1 of the present invention includes an optical element (optical member) 2 which is a focus adjustment optical system. The focal position of the device 1 can be changed continuously.

Inside the lens device 1, the optical element 2 is held by a movable barrel 3, and the movable barrel 3 is fixed to the movable barrel 4 using screws. A total of six cam followers 5 extending two each in three directions perpendicular to the optical axis are fixed to the outer peripheral portion of the movable barrel 4 . The three cam followers 5 on the object side are fixed at equal intervals of 120° around the optical axis, and the three cam followers 5 on the image plane side are in the same phase as the three cam followers 5 on the object side. It is fixed in a position separated by a distance in the direction. The six cam followers 5 are engaged in phase with three straight grooves (linear cams) 6a extending in the optical axis direction provided in a fixed barrel (first fixed barrel) 6, It is possible to slide smoothly.

A focus cam barrel 7 is arranged on the outer peripheral side of the fixed barrel 6 so as to be rotatable with respect to the fixed barrel 6 about the optical axis. A clearance is provided between the outer diameter portion 6b of the fixed barrel 6 and the inner diameter portion 7b of the focus cam barrel 7 based on the difference in diameter. Axial movement is restricted. The dimensions related to the movement of the focus cam barrel 7 in the optical axis direction are processed with high precision, but the minimum necessary range for realizing smooth rotation of the focus cam barrel 7 is limited to the optical axis direction play. is left. As shown in FIGS. 2 and 3, the focus cam barrel 7 has two opposed cam grooves 7a, and a pair of cam followers 13 are engaged with the cam grooves 7a. The cam follower 13 is inserted through a hole 7c provided at the end of the cam groove 7a at the time of assembly, inserted through a straight groove 6c provided in the fixed barrel 6, and fixed to the outer peripheral portion of the movable barrel 4 using screws. .

In the above configuration, the linear groove 6a provided in the fixed barrel 6 and the cam follower 5 are engaged to restrict the movable barrel 4 from tilting and from rotating about the optical axis. When the focus cam barrel 7 rotates around the optical axis, the engagement between the cam groove 7a of the focus cam barrel 7 and the cam follower 13 serves as a guide to move the movable barrel 4 in the direction of the optical axis. ing.

The fixed cylinder 6 is connected and fixed to the fixed cylinder 9 via the fixed cylinder 8 using screws. Here, the connecting portion 6d of the fixed barrel 6 is provided with play based on the difference in diameter, and the optical performance can be adjusted by relatively parallel decentering the object side of the fixed barrel 8 of the lens device 1. can be done.

A focus operation ring 10, which is a rotatable operation member for rotating the focus cam barrel 7 around the optical axis, is engaged with the outside of the fixed barrel (second fixed barrel) 9 at the inner diameter portion and the outer circumference. A focus index indicating the subject distance is engraved on the portion 10a. The engagement portion between the fixed barrel 9 and the focus operation ring 10 can be smoothly rotated. Directional movement is restricted. Although the dimensions related to the movement of the focus operation ring 10 in the optical axis direction are processed with high precision, the minimum necessary range for realizing smooth rotation of the focus operation ring 10 is limited to the optical axis direction play. is left. Further, the focus operation ring 10 is provided with a hole portion 10c into which a tool is inserted in order to tighten screws for connecting and fixing the fixed barrels 6 and 8 after optical adjustment. A rubber band 12 covers the outer periphery of the focus operation ring 10 so as to cover the hole 10c. A portion of the focus operation ring 10 covers the outer peripheral side of the focus cam cylinder 7 .

On the object side of the tip of the focus operation ring 10, a pair of cylindrical connecting pins 14, which are connecting shaft members made of resin, are fixed at two locations on the outer circumference of the focus cam barrel 7 facing each other about the axial direction. It is Assuming that the axial direction of the two connecting pins 14 is the B-axis and the axial direction of the two cam followers 13 is the C-axis, the B-axis and the C-axis are in different directions as shown in FIG. Furthermore, even if the direction of the B-axis changes within the range indicated by the arrow in FIG. 2 as the focus cam barrel 7 rotates, the two axes do not overlap over the entire rotation angle range.

On the other hand, at the same phase as the two connecting pins 14, two connecting plates (plate members) 15, which are rotation transmitting members, are fixed to the distal end portion of the focus operation ring 10. As shown in FIG. The connecting plate 15 is composed of a base portion 15a fixed to the inner peripheral surface of the focus operation ring 10 with two screws, an arm portion 15b elastically deformable in the thickness direction, and a U-shaped groove portion (recess) 15c. . FIG. 4 is a partially enlarged view showing the connected state of the connecting pin 14 and the connecting plate 15. As shown in FIG. Although the connection plate 15 is fixed to the focus operation ring 10 with screws as described above, the focus operation ring 10 is not shown in FIG.

Here, the width of the groove portion 15c of the connecting plate 15 is slightly narrower than the engaging diameter portion (outer diameter portion) 14a of the connecting pin 14. As shown in FIG. Therefore, in the connected state of FIG. 4, the groove portion 15c clamps the engaging diameter portion 14a in a press-fit state in which preload is applied to the engaging portions of both in the groove width direction. The connecting pin 14 constitutes an engaging structure in which the position is held in the groove portion 15c. That is, the connecting member that connects the focus cam barrel 7 and the focus operation ring 10 to each other for rotation about the optical axis is a member fixed to the focus operation ring 10 (an operation member The second portion on the side) and the member fixed to the focus cam barrel 7 (the first portion on the cam barrel side) have an engagement structure in which one sandwiches the other.

Also, the connecting plate 15 is formed of a metal plate, and has high rigidity in the direction parallel to the surface of the plate. Therefore, the amount of deformation of the connecting plate 15 due to the load applied in the direction of the optical axis and in the circumferential direction around the optical axis is negligibly small, and the rotation applied to the focus operation ring 10 can be steadily applied to the focus cam barrel. 7. On the other hand, the rigidity in the direction perpendicular to the surface (radial direction around the optical axis) is low, and when an external force is applied, it is easily elastically deformed like a cantilever with the base 15a as a fulcrum. It has the shape of the arm portion 15b.

When the connecting pin 14 and the connecting plate 15 are engaged with each other, the connecting pin 14 is fixed to the focus cam cylinder 7 and the connecting plate 15 is fixed to the focus operation ring 10 in advance. By inserting the fixed barrel 6 with the focus cam barrel 7 assembled into the fixed barrel 9 with the focus operation ring 10 and the fixed barrel 8 assembled in the optical axis direction, the arm portion 15b is not largely elastically deformed. The connecting pin 14 can be engaged with the groove portion 15c.

Effects obtained by the lens apparatus 1 of the present embodiment with the configuration as described above will be described below.
First, the effect of suppressing the positional fluctuation of the focus cam barrel 7 in the optical axis direction will be described.

When adjusting the focus of the lens device 1 of this embodiment, that is, performing a focus operation, the focus operation ring 10 is rotated around the optical axis. The rotation of the focus operation ring 10 is transmitted to the rotation of the focus cam barrel 7 by the engagement of the connection plate 15 and the connection pin 14, and the movement barrel 4 and the optical element 2 of the focus adjustment optical system are guided by the cam groove 7a. Move (drive) in the axial direction. At this time, the reaction force of the sliding resistance generated when the movable barrel 4 moves in the optical axis direction acts on the focus cam barrel 7 . In the structure of a conventional general lens device, this reaction force easily moves the focus cam barrel within the range of residual play in the optical axis direction. On the other hand, in the lens apparatus 1 of the present embodiment, since the connecting pin 14 fixed to the focus cam barrel 7 exerts a force to maintain the relative position of the connecting plate 15 with respect to the groove 15c, the sliding resistance is reduced. The focus cam barrel 7 is restrained from easily moving by force.

Further, since the connecting pin 14 and the connecting plate 15 maintain their relative positions, the focus cam cylinder 7 and the focus operation ring 10 rotate substantially integrally in the optical axis direction. As a result, the mass and sliding area of the rotating body are increased compared to the focus cam barrel 7 alone, so the resistance to movement in the direction of the optical axis increases on the sliding surface of the engaging portion, and the focus cam barrel 7 becomes easier. An effect of suppressing movement in the optical axis direction can be expected. In particular, when there is play between the inner diameter of the focus cam barrel 7 and the outer circumference of the fixed barrel 6 as in the present embodiment, and there is no engagement portion, the engagement occurs when they are substantially integrated in the optical axis direction. The suppression effect due to the increase in resistance of the sliding surface is large.

Furthermore, in this embodiment, both the focus cam barrel 7 and the focus operation ring 10 restrict the play in the optical axis direction to the minimum necessary amount for smooth rotation. In such a case, it can be expected that the remaining backlash in the optical axis direction will be further reduced by the mutual interaction between the two rotating together in the optical axis direction.

Next, the fact that the configuration of this embodiment does not cause an increase in focus rotation operation torque will be described.

First, since the attitude of the movable barrel 4 is determined by the engagement of the six cam followers 5 and the three linear grooves 6a, it does not have the degree of freedom in the eccentric direction with respect to the fixed barrel 6. As shown in FIG. The focus cam barrel 7 is eccentric only in the C-axis direction in FIG. have freedom. That is, the focus cam barrel 7 has a degree of freedom of eccentricity only in the C-axis direction with respect to the fixed barrel 6 as well.

On the other hand, the focus operation ring 10 engaged with the fixed barrel 9 is connected to the focus cam barrel 7 via the connecting plate 15 and the connecting pin 14, and the arm portion 15b of the connecting plate 15 and the shaft of the connecting pin 14 are connected. It can easily elastically deform in parallel directions. Therefore, the focus cam cylinder 7 has a degree of freedom of eccentricity in the B-axis direction in FIG. As described above, the focus cam barrel 7 has degrees of freedom in one axial direction different from those of the fixed barrel 6 and the fixed barrel 9, respectively. In other words, even if the central axes of the fixed barrels 6 and 9 are deviated in an arbitrary direction by an arbitrary amount, the focus cam barrel 7 moves in the eccentric direction to absorb the displacement. That's what it means.

Therefore, even if the center axis of the fixed cylinders connected to each other is shifted due to the adjustment of the optical performance, etc. as in the present embodiment, the configuration of the present embodiment can prevent the focus from rotating due to the interference between the plurality of engaging portions. No increase in operating torque occurs.

Further, in this embodiment, since no biasing force is generated to bias the focus cam barrel 7 in the optical axis direction, the frictional force on the sliding surface in contact with the optical axis direction does not increase, and the focus rotation operation can be performed. No increase in torque.

As described above, according to the lens apparatus of this embodiment, it is possible to suppress the positional fluctuation of the focus cam barrel 7 in the optical axis direction without causing an increase in rotational operation torque and without increasing the structural size. is. The structure of this embodiment is particularly effective in a lens device in which the central axis of the operation ring and the central axis of the cam structure do not coincide, such as when the central axes of the fixed barrels 6 and 9 are not aligned. Of course, it can also be applied when the central axes of

In this embodiment, the cam follower 13 and the connecting pin 14 are arranged at two opposite positions on the circumference. It is possible to have However, with respect to the effect of suppressing the play of the focus cam barrel 7 in the optical axis direction, although it can be expected at one point for approximately half the circumference, the effect may be insufficient for the remaining approximately half circumference. Therefore, it is more preferable to dispose them at two opposing locations as illustrated in the embodiment.

The structure in which the engaging portions of the connecting pin 14 and the connecting plate 15 are press-fitted is excellent in that a preload can be applied to the connecting pin 14 in a direction perpendicular to the optical axis without increasing the size of the structure. The structure for applying preload is not limited to this. A structure in which a biasing member is used to bias the connecting pin 14 may be used.

Further, when the focus operation ring 10 is a resin molded part having a high degree of freedom in shape and a high degree of freedom in rigidity, the focus operation ring 10 is provided with an engaging portion with the connecting pin 14, and the connecting pin 14 is located near the engaging portion. It may have a shape that is easily elastically deformed in a direction parallel to the axis. That is, even if the focus operation ring 10 and the connecting plate 15 of this embodiment are integrated and made of the same member, the same effects as those of this embodiment can be obtained.

In this embodiment, the connection structure that allows for axial misalignment is applied to the focus adjusting optical system (focusing optical system), but the application of the present invention is not limited to this, but is also applicable to variable magnification optical systems and flange back adjustment. or a macro optical system for macro photography.

Further, an image pickup apparatus having the lens apparatus of the present invention and an image pickup element arranged on the image plane of the lens apparatus can realize an image pickup apparatus that enjoys the effects of the present invention.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist.

Reference Signs List 1 Lens device 4 Moving barrel 7 Focus cam barrel (cam barrel)
10... Focus operation ring (operation member)
14... Connecting pin (connecting shaft member)
15... Connection plate (rotation transmission member)

Claims (13)

an optical member;
a cam barrel that rotates about the optical axis to move the optical member in the direction of the optical axis;
an operating member rotatably operable to rotate the cam barrel about the optical axis ;
a connecting member that connects the cam cylinder and the operating member with respect to rotation about the optical axis;
The connecting member is elastically deformable in a radial direction about the optical axis, and includes a first portion fixed to the cam cylinder and a second portion fixed to the operation member,
The lens device, wherein the first portion and the second portion are engaged with each other so as to suppress variation in relative position in the direction of the optical axis . 2. The lens device according to claim 1, wherein the second portion is elastically deformable by displacement of the first portion in a radial direction about the optical axis. A first fixed barrel formed with a linear cam extending in the direction of the optical axis, and a movable barrel holding the optical member and including a first cam follower engaged with the linear cam. 3. A lens device according to Item 1 or 2. 4. The lens device according to claim 3, wherein said movable barrel includes a second cam follower that engages a cam formed on said cam barrel. 5. The lens device according to claim 4, wherein said second cam follower is arranged at two locations on said movable barrel facing each other with respect to said optical axis. 6. The lens device according to claim 4, wherein the connecting member is arranged so as not to overlap with the second cam follower in the circumferential direction around the optical axis when the cam barrel rotates. . 7. The operating member according to any one of claims 3 to 6, further comprising a second fixed barrel connected to said first fixed barrel, and said operating member engaging said second fixed barrel. The lens device according to . 8. The lens device according to any one of claims 1 to 7, wherein the connecting members are arranged at two locations facing each other with respect to the optical axis . 9. The lens device according to any one of claims 1 to 8, wherein the first and second portions are engaged with each other such that displacement of one portion in the radial direction causes elastic deformation of the other portion. . 10. The lens device according to any one of claims 1 to 9, wherein one of said first and second portions is provided with a recess, and the other is sandwiched by said recess . 11. The lens device according to claim 10, wherein said other is press-fitted into said recess. 12. The lens apparatus according to any one of claims 1 to 11, wherein the optical member is movable during at least one of focusing, zooming, flange back adjustment, and macro photography . An imaging apparatus comprising: the lens apparatus according to any one of claims 1 to 12 ; and an imaging element arranged on an image plane of the lens apparatus.

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