JP2021149015A - Lens device and imaging device - Google Patents

Abstract

To provide a lens device which is advantageous for reducing the collapse and eccentricity of a lens unit.SOLUTION: The lens device comprises: a holding member for holding an optical element; a stationary barrel having a straight groove extending in the optical axis direction; a cam barrel rotatably supported to the stationary barrel and having a cam groove; and a cam follower secured to the holding member and having an engaging part that slidably engages with the straight groove and the cam groove. The holding member includes a plurality guide grooves extending in the optical axis direction, is secured to the stationary barrel and has an engaging member that slidably engages with the guide grooves.SELECTED DRAWING: Figure 1

Description

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

In a lens device used in an optical device such as a digital camera or a video camera, it is known that a lens holding member holding a lens group is moved in the optical axis direction by rotation of a rotating cylinder at the time of focusing or zooming. When moving the lens holding member in the optical axis direction, it is necessary to move the lens group so that the optical axis of the lens group does not tilt or misalign (eccentricity) with respect to the image sensor to maintain good optical performance. It is necessary for.

It is known that a drive mechanism for moving a lens holding member in the optical axis direction uses a cam cylinder having a cam groove, a guide cylinder having a vertical groove parallel to the optical axis direction, and a cam follower engaged with each groove. There is. The cam follower is supported by the lens holding member, and the lens holding member is driven in the optical axis direction by rotating the cam cylinder around the optical axis with respect to the guide cylinder. The fitting play (play) between the cam cylinder and the guide cylinder, and the play of the cam follower with respect to the cam groove and the vertical groove cause the lens holding member to tilt or eccentric with respect to the guide cylinder, resulting in deterioration of optical performance. ..

Patent Document 1 discloses a lens device having a backlash gathering member that is sandwiched between the first and second tubular members and reduces the fitting backlash of both. In Patent Document 2, a second lens holding member is provided in order to align the relative tilt and eccentricity directions and amounts of the first lens holding member and the second lens holding member that can move in the optical axis direction. A lens device having a support mechanism for guiding the first lens holding member in a straight direction is disclosed.

Japanese Unexamined Patent Publication No. 2011-197519 Japanese Unexamined Patent Publication No. 2004-1987742

In the lens device disclosed in Patent Document 1, when it is desired to reduce the collapse of a heavy group, a corresponding urging force is required, which becomes a driving load for zooming and focusing. Further, since the lens device disclosed in Patent Document 2 is configured to suppress the relative eccentricity between the moving members, it is not configured to reduce the absolute amount of tilt and eccentricity.

Therefore, an object of the present invention is to provide a lens device that is advantageous in reducing tilting and eccentricity of the lens unit.

The lens device of the present invention includes a holding member that holds an optical element, a fixed cylinder having a straight groove extending in the optical axis direction, and a cam cylinder rotatably supported by the fixed cylinder and having a cam groove. A lens device having a cam follower fixed to the holding member and having an engaging portion slidably engaged with the straight groove and the cam groove, the holding member extending in the optical axis direction. It has a plurality of guide grooves, and has an engaging member that is fixed to the fixed cylinder and slidably engages with the guide groove.
Other objects and features of the present invention will be described in the following embodiments.

According to the present invention, it is possible to provide a lens device that is advantageous in reducing tilting and eccentricity of a lens unit.

It is sectional drawing of the lens apparatus in Example 1. FIG. It is an exploded perspective view of the lens apparatus in Example 1. FIG. It is a block diagram of the image pickup apparatus in Example 2. FIG. It is a block diagram of the image pickup apparatus in Example 2. FIG.

Hereinafter, the lens apparatus of the present invention will be described in detail with reference to the drawings.

First, the lens apparatus (interchangeable lens) according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1A and 1B are cross-sectional views of a main part of the lens device 100, FIG. 1A shows a cross-sectional view at a wide angle, and FIG. 1B shows a cross-sectional view at a telephoto end. FIG. 2A is an exploded perspective view of a part of the lens device 100, and FIG. 2B is an enlarged view of part A in FIG. 2A. The lens device 100 is an interchangeable lens that can be attached to and detached from the image pickup device main body (camera main body).

The lens device 100 has a guide cylinder (fixed cylinder) 10 and a cam cylinder 11 that support the photographing optical system, and the guide groove provided in the guide cylinder 10 and the cam groove provided in the cam cylinder 11 form at least one of the photographing optical systems. The magnification can be changed by moving the part in the optical axis direction. The guide cylinder 10 is an immovable (fixed) member during scaling and focus adjustment. The guide cylinder 10 and the cam cylinder 11 are diameter-fitted at two locations 10a and 10b, and a plurality of bayonet claws 10c provided on the guide cylinder 10 are engaged with the peripheral groove 11a provided on the cam cylinder 11. .. As a result, the cam cylinder 11 is rotatably supported at a fixed position with respect to the guide cylinder 10 arranged on the inner diameter side thereof.

The lens (optical element) L1 constituting the photographing optical system of the lens device 100 is held by the lens holding member 12. The lens holding member 12 is composed of a group 1 lens barrel 13 that holds the lens L1 and a straight-moving tube 14 that fixes the group 1 lens barrel 13. The lens L1 is fixed to the group 1 lens barrel 13 by heat clamping, and the group 1 lens barrel 13 is fixed to the straight cylinder 14 by a screw. Three cam followers 15 are fixed to the straight cylinder 14 by screws 16, and the cam followers 15 are a guide groove (straight groove) 10d and a cam cylinder 11 provided on the guide cylinder 10 arranged on the inner diameter side of the straight cylinder 14. Each of the cam grooves 11b provided in the above is slidably engaged with each other. As a result, when the cam cylinder 11 rotates with respect to the guide cylinder 10, the lens holding member 12 can move from the wide-angle position shown in FIG. 1 (a) to the telephoto position shown in FIG. 1 (b).

Here, the tilting and eccentricity of the lens holding member 12 will be described. The guide cylinder 10 and the cam cylinder 11 have play between the diameter fitting portions 10a and 10b, and the bayonet claw 10c and the peripheral groove 11a. The cam cylinder 11 is eccentric with respect to the guide cylinder 10 due to the play of the diameter fitting portion. When the cam cylinder 11 is eccentric, the position where the cam of the cam follower 15 that engages with the cam groove 11b is used changes, and the lens holding member 12 collapses. Further, the cam cylinder 11 is tilted with respect to the guide cylinder 10 due to the play of the bayonet portion, and the lens holding member 12 is also tilted by the amount of the cam cylinder 11 being tilted. Further, the lens holding member 12 is tilted and eccentric due to the mutual positional accuracy of each of the plurality of guide grooves 10d and the cam groove 11b, that is, the component accuracy. The lens holding member 12 is tilted around the cam follower 15 as a fulcrum, and the farther the distance between the cam follower 15 and the lens L1 is, the larger the tilt of the lens L1 and the amount of eccentricity.

In order to realize high optical performance, it is a necessary condition that there is little deviation from the ideal optical axis OA. In this embodiment, the engaging member 17 is fixed to the guide cylinder 10 by a screw 18. Before explaining the effect of the engaging member 17, the assembling order will be described. First, with the cam follower 15 engaged with the guide cylinder 10 and the cam cylinder 11, the positions of the straight cylinder 14 and the cam follower 15 in the optical axis direction are aligned, and the cam follower 15 is pulled in by the screw 16 to pull the cam follower 15 into the straight cylinder 14. 15 is fixed. Next, in the telephoto state shown in FIG. 1 (b), the engaging member 17 is inserted through the straight cylinder 14 in the radial direction from the insertion hole (through hole) 14a provided so that the engaging member 17 can penetrate. It is inserted and the engaging member 17 is fixed (fastened) to the guide cylinder 10 with a screw 18. At this time, a guide groove 14b that engages with the engaging member 17 extends in the optical axis direction inside the insertion hole 14a (inner peripheral surface), and the engaging member 17 can slide in the guide groove 14b. It is fixed to the guide cylinder 10 in a state of being engaged with. At that time, the width of the engaging member 17 is set to be narrower than that of the guide groove 14b. As shown in FIG. 2B, the guide cylinder 10 has a flat surface portion (seat) 10e that abuts on the engaging member 17, and the flat surface portion 10e has a straight line portion 10f extending in the circumferential direction. By engaging the linear portion 10f with the engaging member 17, the position of the engaging member 17 in the optical axis direction is determined. In the circumferential direction, the length of the flat surface portion 10e is longer than the length of the engaging member 17. The engaging member 17 is fixed to the guide cylinder 10 with a screw 18, but a slight deviation in the circumferential position where the engaging member 17 is fixed is allowed (absorbed) with respect to the position of the screw hole of the guide cylinder 10. ), The hole of the engaging member 17 through which the screw 18 passes is set to be adjustable with a corresponding margin. Alternatively, it is designed so that the position of the screw 18 and the position of the engaging member 17 can have a margin that cannot be strictly determined in the circumferential direction. That is, the position of the engaging member 17 in the circumferential direction is defined by following the position of the guide groove 14b, and is determined by absorbing the result of each component. With such a configuration, the engaging member 17 can be incorporated without becoming a driving load when the lens holding member 12 moves in the optical axis direction.

The effect of the engaging member 17 will be described. As described above, the lens holding member 12 falls down with the cam follower 15 as a fulcrum due to the influence of each play and the result of the parts. In this embodiment, the lens holding member 12 has an engaging member 17 that engages with the guide groove 14b provided in the straight cylinder 14, and the lens holding member 12 falls over a predetermined amount due to the influence of each play and the result of the parts. Or, when eccentricity occurs, one side surface of the guide groove 14b comes into contact with the engaging member 17. In particular, the engaging member 17 that is not in the vertical cross section including the optical axis comes into contact with one side surface of the guide groove 14b with which the engaging member 17 is engaged. This makes it possible to reduce the tilting and eccentricity of the lens holding member 12. As an effect of reducing tilting and eccentricity, the longer the distance between the cam follower 15 and the engaging member 17, the greater the effect, and in this embodiment, the effect is greater at the wide angle shown in FIG. 1 (a). Further, it also has a side surface that the impact received by the cam follower 15 at the time of an impact such as dropping is dispersed to the engaging member 17, and the plastic deformation of the cam follower 15 can be reduced, that is, it is possible to provide a lens device that is strong against the impact.

The image pickup apparatus (camera system) according to the second embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a configuration diagram of the image pickup apparatus 200. In FIG. 3, the lens device 100 (interchangeable lens) has an imaging optical system 1 (lens unit). The camera body 120 (imaging device main body) includes a quick return mirror 3, a focusing plate 4, a pentadach prism 5, an eyepiece 6, and the like. The quick return mirror 3 reflects the light flux formed through the imaging optical system 1 upward. The focal plate 4 is arranged at an image forming position of the imaging optical system 1. The pentadha prism 5 converts the inverse image formed on the focal plate 4 into an upright image. The user can observe the erect image through the eyepiece 6.

The image pickup device 7 includes a CCD sensor and a CMOS sensor, and outputs image data by photoelectrically converting an optical image (subject image) formed via the image pickup optical system 1. At the time of shooting, the quick return mirror 3 retracts from the optical path, and an optical image is formed on the image sensor 7 via the image pickup optical system 1. The control unit 110 has a CPU and controls the operation of each unit of the image pickup apparatus 200.

FIG. 4 shows a block configuration of a camera system of the lens device 100 and the camera body 120. The camera CPU 130 is composed of a microcomputer and controls the operation of each part in the camera body 120. Further, when the lens device 100 is attached, the camera CPU 130 communicates with the lens CPU 102 provided in the lens device 100 via the electric contact 101 and the electric contact 121. The information transmitted by the camera CPU 130 to the lens CPU 102 includes information on the amount of drive of the focus lens and the like. Further, the information transmitted from the lens CPU 102 to the camera CPU 130 includes imaging magnification information and the like. The electric contact 101 and the electric contact 121 also include a contact for supplying power from the camera body 120 to the lens device 100. The power switch 131 is a switch that can be operated by the photographer, and is operated to start the camera CPU 130 and to start supplying power to actuators, sensors, and the like in the camera system.

First, the control of the camera body 120 will be described. The release switch 132 is a switch that can be operated by the photographer, and has a first stroke switch SW1 and a second stroke switch SW2. The signal from the release switch 132 is input to the camera CPU 130. The camera CPU 130 enters the shooting preparation state in response to the input of the ON signal from the first stroke switch SW1. In the shooting preparation state, the subject brightness is measured by the photometric unit 133 and the focus is detected by the focus detection unit 134. The camera CPU 130 calculates the aperture value of an aperture unit (not shown) mounted in the lens device 100, the exposure amount of the image sensor 7 (at the time of shutter seconds), and the like based on the light measurement result. Further, the camera CPU 130 determines the driving amount of the focus lens (not shown) for obtaining the in-focus state with respect to the subject based on the focus information of the photographing optical system by the focus detection unit 134. The drive amount information (focus lens drive amount information) is transmitted to the lens CPU 102. The lens CPU 102 controls the operation of each component of the lens device 100. Further, the camera CPU 130 starts controlling the vibration isolation operation of the image shake correction device (not shown) when the predetermined shooting mode is set.

When the ON signal from the second stroke switch SW2 is input, the camera CPU 130 transmits an aperture drive command to the lens CPU 102 to set the aperture unit to the aperture value calculated above. Further, the camera CPU 130 transmits an exposure start command to the exposure unit 135 to cause the quick return mirror 3 to retract and release a shutter (not shown), and the image sensor 136 including the image sensor 7 exposes the subject image. To do. The image pickup signal from the image pickup unit 136 (image sensor 7) is digitally converted by the signal processing unit in the camera CPU 130, further subjected to various correction processing, and output as an image signal. The image signal data is written and stored in the image recording unit 137 in a semiconductor memory such as a flash memory or a recording medium such as a magnetic disk or an optical disk.

Next, the control of the lens device 100 will be described. The ZOOM operation amount detection unit 103 detects the rotation of the zoom ring (not shown) by a sensor (not shown). The MF operation amount detection unit 104 detects the rotation of the manual focus ring (not shown) by a sensor (not shown). The image shake correction drive unit 105 includes a drive actuator of the image shake correction device and a drive circuit thereof. The electromagnetic aperture drive unit 106 brings the aperture unit into an aperture state corresponding to a specified aperture value by the lens CPU 102 that receives an aperture drive command from the camera CPU 130. The FOCUS drive unit 107 drives the focus lens by a focus drive mechanism (not shown) according to the focus drive amount information transmitted from the camera CPU 130.

The angular velocity detection unit 108 includes an angular velocity sensor (not shown). The angular velocity detection unit 108 detects the pitch direction (vertical rotation) runout and the yaw direction (horizontal rotation) runout, which are angular velocities, by the angular velocity sensor, and outputs the respective angular velocities to the lens CPU 102. The lens CPU 102 integrates the angular velocity signals in the pitch direction and the yaw direction from the angular velocity sensor, and calculates the amount of angular displacement in each direction. Then, the lens CPU 102 controls the image shake correction driving unit 105 according to the above-mentioned angular displacement amounts in the pitch direction and the yaw direction to drive the lens group of the image shake correction device in the vertical direction and the horizontal direction, thereby causing the image shake. Correction is possible.

The image pickup device 200 is composed of a camera body 120 having an image pickup element 7 and a lens device 100 detachably attached to the camera body 120, but the image pickup device 200 is not limited thereto. An image pickup device in which a camera body and a lens device are integrally configured may be used, or a mirrorless single-lens reflex camera without a quick return mirror may be used.

According to each embodiment, it is possible to provide a lens device and an imaging device capable of reducing tilting and eccentricity of the lens unit without increasing the driving load of the lens unit.
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

For example, although the shape of the engaging member 17 is a cylindrical shape, the outer shape may be square. Even in that case, the same effect can be obtained by making the length of the flat surface portion 10e of the guide cylinder 10 in the circumferential direction longer than the length of the engaging member 17 in the circumferential direction. Further, although the cam follower 15 and the engaging member 17 are arranged in the same phase, they may be arranged in different phases.

10 Guide cylinder 11 Cam cylinder 12 Lens holding member 15 Cam follower 17 Engaging member 100 Interchangeable lens (lens device)

Claims (8)

A holding member that holds the optical element and
A fixed cylinder with a straight groove extending in the optical axis direction,
A cam cylinder that is rotatably supported by the fixed cylinder and has a cam groove,
A cam follower fixed to the holding member and having an engaging portion that is slidably engaged with the straight groove and the cam groove.
It is a lens device having
The holding member has a plurality of guide grooves extending in the optical axis direction, and has a plurality of guide grooves.
It has an engaging member that is fixed to the fixing cylinder and slidably engages with the guide groove.
A lens device characterized by that. The lens device according to claim 1, wherein the holding member has three guide grooves. The lens device according to claim 1 or 2, wherein the guide groove is a groove formed on an inner peripheral surface of the holding member and extending in the optical axis direction. The lens device according to any one of claims 1 to 3, wherein the cam cylinder is arranged on the inner diameter side of the holding member, and the fixed cylinder is arranged on the inner diameter side of the cam cylinder. The lens device according to any one of claims 1 to 4, wherein the holding member has a through hole through which the engaging member can penetrate and penetrates the holding member in the radial direction. The lens device according to any one of claims 1 to 5, wherein the engaging member is fixed in an adjustable position with respect to the fixed cylinder in the circumferential direction. The lens device according to claim 6, wherein the fixed cylinder has a seat that is brought into contact with and fastened to the engaging member, and the seat has a straight portion extending in the circumferential direction. An image pickup apparatus comprising the lens apparatus according to any one of claims 1 to 7 and an image pickup device that receives an image formed by the lens apparatus.

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