Lens barrel and image pickup apparatus

Abstract

To miniaturize a lens barrel.SOLUTION: A lens barrel includes a first lens, a first barrel that holds the first lens and has a first cam follower, a second lens, a second barrel that holds the second lens, a focus lens, a focus lens frame, an actuator, a third barrel that has a second cam follower, and a cam barrel that has a first cam groove that engages with the first cam follower and a second cam groove that engages with the second cam follower and that is rotatable about an optical axis. When the cam barrel rotates, the first barrel and the third barrel move in the optical axis direction in different trajectories due to the first cam groove and the second cam groove of the cam barrel, the actuator and the focus lens frame move in the optical axis direction with the movement of the third barrel in the optical axis direction, and the focus lens frame is moved in the optical axis direction with respect to the third barrel by the actuator.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a lens barrel and an imaging device. [Background technology]

[0002] A zoom lens barrel consisting of a fixed lens group, a variable magnification lens group, and a focusing lens group is known (see Patent Document 1). This zoom lens barrel is configured such that a focus lens drive source supported by the barrel is connected to a focus lens holding frame, and the focusing lens group is moved in the optical axis direction by driving the drive source. However, during zooming, when the variable magnification lens holding frame moves in the optical axis direction, the distance between the variable magnification lens holding frame and the drive source for the focus lens, etc. must be sufficiently large so that the variable magnification lens holding frame does not interfere with the drive source for the focus lens, etc., which increases the overall length of the lens barrel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent No. 3186543 Summary of the Invention

[0004] A lens barrel according to a first aspect of the present invention includes a first lens, a first barrel that holds the first lens and has a first cam follower, a second lens, a second frame that holds the second lens, a focus lens that is arranged between the first lens and the second lens and that is arranged facing each of the first lens and the second lens, a focus lens frame that holds the focus lens, an actuator that drives the focus lens, a third barrel that holds the actuator and has a second cam follower, a first cam groove that engages with the first cam follower, and a second cam groove that engages with the second cam follower. and a cam barrel rotatable around the optical axis, wherein at least a portion of the focus lens frame is disposed on the inner peripheral side of the third barrel, and the third barrel does not directly hold the focus lens or the focus lens frame, and when the cam barrel rotates, the first barrel and the third barrel move along different trajectories in the optical axis direction due to the first cam groove and the second cam groove of the cam barrel, and as the third barrel moves along the optical axis direction, the actuator and the focus lens frame move along the optical axis, and the focus lens frame moves in the optical axis direction relative to the third barrel by the actuator. An imaging device according to a second aspect of the present invention includes the lens barrel according to the first aspect. [Brief explanation of the drawings]

[0005] [Figure 1] 1 is a perspective view showing an interchangeable lens camera system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a portion of an interchangeable lens barrel in an extended state. [Figure 3] FIG. 2 is a cross-sectional view of a portion of an interchangeable lens barrel in an extended state. [Figure 4] FIG. 2 is an exploded view of a part of the interchangeable lens barrel. [Figure 5] FIG. 2 is an exploded view of a part of the interchangeable lens barrel. [Figure 6] FIG. 2 is an exploded view of a part of the interchangeable lens barrel. [Figure 7]FIG. 2 is a cross-sectional view of a portion of an interchangeable lens barrel in a retracted state. [Figure 8] FIG. 10 is a perspective view showing an interchangeable lens camera system according to a second embodiment of the present invention. [Figure 9] FIG. 2 is a cross-sectional view of a portion of an interchangeable lens barrel in an extended state. [Figure 10] FIG. 2 is a cross-sectional view of a portion of an interchangeable lens barrel in an extended state. [Figure 11] FIG. 2 is a cross-sectional view of a portion of an interchangeable lens barrel in an extended state. [Figure 12] FIG. 2 is a cross-sectional view of a portion of an interchangeable lens barrel in an extended state. [Figure 13] FIG. 2 is an exploded view of a part of the interchangeable lens barrel. [Figure 14] FIG. 2 is an exploded view of a part of the interchangeable lens barrel. [Figure 15] FIG. 2 is an exploded view of a part of the interchangeable lens barrel. [Figure 16] FIG. 2 is a cross-sectional view of a portion of an interchangeable lens barrel in a retracted state. [Figure 17] FIG. 2 is a cross-sectional view of a portion of an interchangeable lens barrel in a retracted state. DETAILED DESCRIPTION OF THE INVENTION

[0006] First Embodiment A first embodiment of the lens barrel will be described with reference to FIGS. 1 is a perspective view showing a lens-interchangeable camera system equipped with a lens barrel of the present embodiment as an interchangeable lens. Camera system 1 has a camera body 100 and an interchangeable lens barrel 200 that is detachable from camera body 100.

[0007] The camera body 100 is provided with a body-side lens mount 101 to which an interchangeable lens barrel 200 is detachably attached. The interchangeable lens barrel 200 is also provided with a lens-side lens mount 201 that corresponds to the body-side lens mount 101 and to which the camera body 100 is detachably attached. When the interchangeable lens barrel 200 is attached to the camera body 100, a contact group 102 made up of multiple contacts provided on the body-side lens mount 101 connects to a contact group 202 made up of multiple contacts provided on the lens-side lens mount 201. The contact groups 102 and 202 are used to supply power from the camera body 100 to the interchangeable lens barrel 200, and to send and receive signals between the camera body 100 and the interchangeable lens barrel 200.

[0008] An image sensor 104 that captures a subject image and outputs an image signal is provided behind a body-side lens mount 101 inside the camera body 100. Buttons 107, which serve as an input device, are provided above the camera body 100. The user uses the buttons 107 to give instructions to the camera body 100 for shooting, setting shooting conditions, and the like. The buttons 107 are a representative representation of multiple buttons with various functions that are provided in multiple locations on the camera body 100.

[0009] The interchangeable lens barrel 200 of this embodiment has a fixed barrel 211 composed of first and second cylindrical members 211a and 211b that cover the outer periphery of the interchangeable lens barrel 200, and a zoom ring 205 disposed between the first and second cylindrical members 211a and 211b. The interchangeable lens barrel 200 is a so-called manual zoom lens configured so that the focal length can be changed by the user manually operating the zoom ring 205. When the user rotates the zoom ring 205, the focal length of the interchangeable lens barrel 200 changes continuously toward the wide-angle end or the telephoto end. In other words, the focal length of the interchangeable lens barrel 200 can be set arbitrarily between the wide-angle end position and the telephoto end position by operating the zoom ring 205.

[0010] As will be described in detail later, the interchangeable lens barrel 200 is a retractable barrel that can be in an extended state in which a lens inner barrel 203, which holds all or part of the photographic optical system, extends from a fixed barrel 211, and in a retracted state in which the lens inner barrel is housed within the fixed barrel 211. In Fig. 1, the lens inner barrel 203 in the extended state is shown by a dashed line.

[0011] The interchangeable lens barrel 200 is switched between an extended state and a retracted state by operating the retraction release button 204 and the zoom ring 205. That is, in the extended state, the interchangeable lens barrel 200 has the inner barrel 203 extended, i.e., protruding, from the fixed barrel 211, and the barrel length L of the interchangeable lens barrel 200 is L1. In this extended state, the interchangeable lens barrel 200 can form a good subject image on the image sensor 104 throughout its entire zoom range. To switch from the extended state to the retracted state, the zoom ring 205 is rotated while pressing the retraction release button 204, thereby rotating the zoom ring 205 further toward the wide-angle side than the rotation position for moving the focal length of the lens to the wide-angle end. This further rotation retracts the inner barrel 203 into the fixed barrel 211, and the interchangeable lens barrel 200 enters the retracted state. The barrel length L2 in this retracted state is shorter than the barrel length L1 in the extended state. The retracted barrel release button 204 is part of a configuration that performs a mechanical locking function that physically prohibits the lens from transitioning to the retracted barrel state when the lens is positioned between the wide-angle end and the telephoto end.

[0012] When the interchangeable lens barrel 200 is in the retracted state, the zoom ring 205 cannot be rotated unless the retraction release button 204 is also pressed. In other words, the retraction release button 204 is part of a configuration that performs a mechanical locking function that physically prohibits transitioning from the retracted state to the extended state.

[0013] Thus, in order to bring the interchangeable lens barrel 200 from the extended state into the retracted state, the user must rotate the zoom ring 205, which is at a rotation operation position corresponding to the wide-angle end, further toward the wide-angle side while pressing the retraction release button 204. Conversely, in order to bring the interchangeable lens barrel 200 from the retracted state into the extended state, the user must rotate the zoom ring 205 toward the telephoto side while pressing the retraction release button 204.

[0014] 2 and 3 are cross-sectional views of a portion of the interchangeable lens barrel 200 in the extended state. Fig. 2 is a diagram showing a cross section in which the main guide bar 261 and the sub guide bar 262 are visible, and Fig. 3 is a diagram showing a cross section in which the main guide bar 261 and the AF stepping motor 270 are visible. Figs. 4 to 6 are exploded views of a portion of the interchangeable lens barrel 200.

[0015] As shown in FIG. 2, the interchangeable lens barrel 200 has a fixed barrel 211, a zoom ring 205, a cam barrel 212 that fits into the inner periphery of the fixed barrel 211, a first lens group chamber 220 that fits into the inner periphery of the cam barrel 212, a stepping motor (STM) mounting barrel 230, an AF group lens chamber 240, and a second lens group chamber 250. In this embodiment, when the first lens group chamber 220 is in the extended state, it projects from the fixed barrel 211, i.e., corresponds to the extending inner barrel 203 in FIG. 1. In addition, in FIGS. 2 and 3, the left side is the subject side and the right side is the image sensor side. Note that another lens may be located closer to the subject than the first lens group chamber 220. Also, another lens may be located closer to the image sensor than the second lens group chamber 250.

[0016] As shown in FIG. 2, the zoom ring 205 is disposed between the first and second cylindrical members 211 a and 211 b of the fixed barrel 211 as described above, and this zoom ring 205 is fixed to the cam barrel 212 . In this way, the cam barrel 212 is rotated by the rotation of the zoom ring 205, and is provided with a first cam groove 212a and a second cam groove 212b on the inner circumferential side.

[0017] 2 and 4, the first lens group chamber 220 has a cylindrical barrel portion 221 and a hollow, disk-shaped lens holder 222 that holds the first lens group 223 on the subject side of the barrel portion 221. The lens holder 222 is fixed to the left end of the barrel portion 221. A cam follower 221a that fits into a first cam groove 212a of the cam barrel 212 is provided on the outer periphery of the barrel portion 221, and the first lens group chamber 220 moves linearly as the cam barrel 212 rotates. In other words, when the user rotates the zoom ring 205, the first lens group chamber 220 moves in the direction of the optical axis OA.

[0018] A main guide bar 261 and a sub guide bar 262 are attached to the lens holder 222 to guide the STM mounting barrel 230 and the AF group lens chamber 240 in the direction of the optical axis OA. The main guide bar 261 and the sub guide bar 262 are disposed near positions facing each other across the optical axis OA, with their object-side ends attached to the lens holder 222 and extending along the optical axis OA toward the image sensor (see FIGS. 4-6). As shown in FIG. 4, a pair of screw holes 221b and 221c are provided at the right end of the barrel 221 of the first group lens chamber 220, i.e., the end on the image sensor side. A main guide bar adjustment plate 263 is attached to the right end of the barrel 221 with a screw (not shown) and the pair of screw holes 221b and 221c. The end of the main guide bar 261 on the image sensor side is attached to the main guide bar adjustment plate 263. Thus, one end of main guide bar 261 is supported by lens holding portion 222, and the other end is supported by main guide bar adjustment plate 263. By adjusting the attachment position of main guide bar adjustment plate 263 to tube portion 221, main guide bar 261 can be made parallel to optical axis OA. Furthermore, the end of sub guide bar 262 on the imaging element side is not supported, i.e., is not fixed.

[0019] The STM mounting barrel 230 is a component mounted within the first lens group chamber 220 via a main guide bar 261 and a sub-guide bar 262, and has an AF stepping motor 270 attached thereto, as shown in FIGS. 4-6 . The STM mounting barrel 230 has a partially cylindrical barrel section 235, a flange-shaped first guide plate 231 attached to one end face of the barrel section 235, a second guide plate 232 spaced apart from the first guide plate 231 in the direction of the optical axis OA, a connecting section 233 attached to the barrel section 235 and connecting the first and second guide plates 231 and 232 to each other, and an STM mounting section 234 attached to the barrel section 235. Cam followers 233a and 235a that fit into the second cam groove 212b of the cam barrel 212 are provided on the outer peripheries of the connecting section 233 and the barrel section 235, and the STM mounting barrel 230 moves linearly as the cam barrel 212 rotates. That is, when the user rotates the zoom ring 205 to change the focal length of the interchangeable lens barrel 200, the STM attachment barrel 230 moves in the direction of the optical axis OA.

[0020] The AF stepping motor 270 is fixed to the STM mounting portion 234 with screws or the like. The first guide plate 231 has an insertion hole 231a through which the main guide bar 261 is inserted and an insertion hole 231b through which the sub guide bar 262 is inserted. The second guide plate 232 has an insertion hole 232a through which the main guide bar 261 is inserted.

[0021] The STM mounting barrel 230 is slidable along the optical axis OA direction relative to the main guide bar 261 and the sub guide bar 262, and is guided by the main guide bar 261 and the sub guide bar 262 to move along the optical axis OA direction relative to the first group lens chamber 220.

[0022] The AF stepping motor 270 has an output shaft directly connected to a lead screw 271, and is actuated for focusing and zooming operations.

[0023] 2, the AF group lens housing 240 is attached to the first group lens housing 220 via a main guide bar 261 and a sub guide bar 262, and holds an AF group lens 241. The AF group lens 241 is a focusing lens, and also constitutes a zooming lens in combination with the first group lens 223.

[0024] The AF group lens chamber 240 is provided with insertion holes 240a and 240b through which the main guide bar 261 is inserted, and a semicircular hole 240c through which the sub guide bar 262 is inserted. The AF group lens chamber 240 is guided by the main guide bar 261 and the sub guide bar 262 so as to be slidable along the optical axis OA direction.

[0025] 3 and 4, a rack portion 242 is attached to the AF group lens chamber 240. A thread is formed in the rack portion 242 to engage with a lead screw 271 of the AF stepping motor 270. In this way, the AF stepping motor 270 attached to the STM mounting barrel 230 and the AF group lens chamber 240 are connected to each other by the engagement of the lead screw 271 and the rack portion 242. Therefore, when the AF stepping motor 270 is rotated, the AF group lens chamber 240 is moved in the optical axis OA direction relative to the STM mounting barrel 230, and when the zoom ring 205 is rotated as described above, the AF group lens chamber 240 is moved in the optical axis OA direction together with the STM mounting barrel 230.

[0026] In this manner, in this embodiment, AF group lens chamber 240 driven by AF stepping motor 270 and STM mounting barrel 230 to which AF stepping motor 270 is attached are configured to move in the direction of optical axis OA while being guided by the same main guide bar 261. Therefore, by adjusting the mounting position of main guide bar adjustment plate 263 on barrel portion 221 to adjust the inclination of main guide bar 261 with respect to optical axis OA, the movement direction of AF stepping motor 270 and AF group lens chamber 240 along the extension direction of main guide bar 261 is also adjusted. This stabilizes the meshing between the lead screw 271 and the rack portion 242. In other words, the tilt of the main guide bar 261 with respect to the optical axis OA can be adjusted without affecting the meshing between the lead screw 271 and the rack portion 242, thereby stabilizing the accuracy of focus control. For example, to improve the optical performance of the interchangeable lens barrel 200, the attitude of the AF group lens 241 may be adjusted by intentionally tilting the main guide bar 261 with respect to the optical axis OA. In this embodiment, even if the main guide bar 261 is tilted with respect to the optical axis OA, the accuracy of focus control is stabilized as described above, which contributes to improving the optical performance of the interchangeable lens barrel 200.

[0027] 2, the second lens group chamber 250 is a lens chamber that holds the second lens group 251. In this embodiment, the second lens group chamber 250 is fixed. As shown in FIGS. 2 and 3, the second lens group chamber 250 is spaced apart from the STM mounting barrel 230 and the AF group lens chamber 240.

[0028] ---Operation of each part of the interchangeable lens barrel 200 in the extended state--- First, the zooming operation of the interchangeable lens barrel 200 will be described. In Fig. 2, when the interchangeable lens barrel 200 is in the extended state, rotating the zoom ring 205 rotates the cam barrel 212, causing the first lens group housing 220 and the STM mounting barrel 230 to move in the direction of the optical axis OA according to the first and second cam grooves 212a and 212b, respectively. As the first lens group housing 220 moves, the first lens group 223 moves in the direction of the optical axis. At the same time, as the STM mounting barrel 230 moves, the AF group lens 241 also moves in the direction of the optical axis due to the connection between the AF stepping motor 270 and the AF group lens housing 240. In this way, the magnification change operation, i.e., the zooming operation, is performed while the focal position is maintained. As described above, the interchangeable lens barrel 200 of this embodiment performs a magnification change operation while keeping the focus position unchanged by moving the first group lens 223 and the AF group lens 241 relatively in the optical axis direction by rotating the zoom ring 205. However, when moving the first group lens 223 and the AF group lens 241 in the optical axis direction by rotating the zoom ring 205 in this way, the AF group lens 241 may be moved to the optical axis OA relative to the STM mounting barrel 230 by the AF stepping motor 270. This makes it possible to suppress fluctuations in the focus position during zooming with high precision.

[0029] Next, we will explain the focusing operation of the interchangeable lens barrel 200. When the AF stepping motor 270 shown in Figure 3 is driven in the extended state of the interchangeable lens barrel 200, the AF group lens chamber 240 is moved along the optical axis OA relative to the STM mounting barrel 230, as described above, and the AF group lens 241 is also moved in the same direction, changing the focal position, i.e., the in-focus position.

[0030] In the extended state, the AF group lens 241 and the second group lens 251 do not interfere with each other, regardless of the focal length or the in-focus position.

[0031] ---When transitioning from an extended state to a compressed state--- Next, we will explain the retraction operation of the interchangeable lens barrel 200. When the zoom ring 205 is rotated in a predetermined direction while pressing the retraction release button 204 shown in Figure 1 to move from the extended state to the retracted state, the first lens group chamber 220 and the STM mounting barrel 230 shown in Figure 2 move toward the second lens group chamber 250 along the first and second cam grooves 212a and 212b, respectively. Note that when the STM mounting barrel 230 moves as described above, the AF group lens chamber 240, which is connected to the AF stepping motor 270 attached to the STM mounting barrel 230, also moves integrally with the STM mounting barrel 230.

[0032] Then, when the zoom ring 205 is further rotated in the predetermined direction while pressing the retraction release button 204, only the first lens group housing 220 moves further in the same direction by a predetermined amount while the STM attachment barrel 230 is stopped, and the retraction operation is completed. In this way, the interchangeable lens barrel 200 enters the retracted state shown in Figure 7. When the STM attachment barrel 230 stops, the AF group lens housing 240 also stops due to the connection between the AF stepping motor 270 and the AF group lens housing 240.

[0033] 7, the distance between the lens holding portion 222 of the first lens group chamber 220 and the first guide plate 231 of the STM mounting barrel 230 is smaller than the distance in the extended state. Also, the distance between the lens holding portion 222 of the first lens group chamber 220 and the second lens group chamber 250 is smaller than the distance in the extended state. In this state, the first lens group chamber 220 is housed within the fixed barrel 211.

[0034] In the retracted state, the AF group lens 241 and the second group lens 251 do not interfere with each other, regardless of the position of the AF group lens 241.

[0035] ---When transitioning from a compressed state to an extended state--- Next, we will explain the extension operation of the interchangeable lens barrel 200. To change from the retracted state to the extended state, when the zoom ring 205 is rotated in the opposite direction to that used during retraction while pressing the retraction release button 204 shown in Fig. 1, the first lens group chamber 220 shown in Fig. 7 moves in the opposite direction to that used during retraction, i.e., in the direction away from the second lens group chamber 250, and returns to the extended state shown in Fig. 2 or 3.

[0036] According to the first embodiment described above, the following advantageous effects can be obtained. (1) The interchangeable lens barrel 200 includes an AF group lens chamber 240 that holds an AF group lens 241, an AF stepping motor 270 that is connected to the AF group lens chamber 240 and drives the AF group lens chamber 240 in the direction of the optical axis OA, an STM mounting barrel 230 to which the AF stepping motor 270 is attached, and a main guide bar 261 that guides the AF group lens chamber 240 and the STM mounting barrel 230 movably in the direction of the optical axis OA. The AF group lens chamber 240 driven by the AF stepping motor 270 and the STM mounting cylinder 230 to which the AF stepping motor 270 is attached are configured to move in the direction of the optical axis OA while being guided by the same main guide bar 261, so that the meshing between the lead screw 271 and the rack portion 242 is stable, and the accuracy of focus control is stable.

[0037] (2) The interchangeable lens barrel 200 includes a first lens group housing 220 to which a main guide bar 261 is fixed. The first lens group housing 220 moves in the direction of the optical axis OA during zooming. This allows the AF group lens group housing 240 and the STM mounting barrel 230 to move accurately in the direction of the optical axis OA relative to the first lens group housing 220.

[0038] (3) The interchangeable lens barrel 200 further includes a cam barrel 212 that rotates around the OA optical axis as the center of rotation during zooming. The first lens group chamber 220 holds a first lens group 223 included in the interchangeable lens barrel 200. The STM mounting barrel 230 includes a cam follower 233a that is moved in the optical axis OA direction by the cam barrel 212, and the first lens group chamber 220 includes a cam follower 221a that is moved in the optical axis OA direction by the cam barrel 212. This allows the first lens group chamber 220 and the STM mounting barrel 230 to be brought closer together when the barrel is retracted, thereby shortening the barrel length L in the retracted state. As a result, the interchangeable lens barrel 200 can be made smaller.

[0039] (4) The interchangeable lens barrel 200 further includes a first lens group chamber 220 to which a main guide bar 261 is fixed, and a cam barrel 212 that rotates around the optical axis OA during zooming. The main guide bar 261 has an axis extending along the optical axis OA. The first lens group chamber 220 includes a lens holder 222 and a barrel portion 221 to which one end of the main guide bar 261 is fixed, and a main guide bar adjustment plate 263 to which the other end of the main guide bar 261 is fixed. The barrel portion 221 has a cylindrical shape centered on the optical axis OA, and the STM mounting barrel 230 is disposed on its inner periphery. The main guide bar adjustment plate 263 is a plate member that is disposed in a direction substantially perpendicular to the optical axis OA and is fixed to the barrel portion 221. This allows the movement direction of the AF group lens 241 relative to the first group lens 223 to be appropriately adjusted during magnification change and focusing operations, thereby improving the optical performance of the interchangeable lens barrel 200.

[0040] (5) The interchangeable lens barrel 200 further includes a cam barrel 212 and a cam follower 221a that fits into the first cam groove 212a of the cam barrel 212, which moves at least the first lens group chamber 220 in the optical axis OA direction to shorten the overall length of the interchangeable lens barrel 200. The cam barrel 212 and the cam follower 221a that fits into the first cam groove 212a of the cam barrel 212 move the main guide bar 261 relative to the STM mounting barrel 230 and the AF group lens chamber 240 as the first lens group chamber 220 moves in the optical axis OA direction. This allows the first lens group chamber 220 and the STM mounting barrel 230 to be brought closer together when the barrel is retracted, thereby shortening the barrel length L in the retracted state. As a result, the interchangeable lens barrel 200 can be made smaller.

[0041] The following modifications are also within the scope of the present invention, and one or more of the modifications may be combined with the above-described embodiment. (Variation 1) Other DC motors or ultrasonic motors may be used instead of the AF stepping motor 270. Furthermore, the number of lenses constituting the first lens group 223, the number of lenses constituting the AF lens group 241, and the number of lenses constituting the second lens group 251 are not limited to the numbers shown in the illustration, and may be increased or decreased.

[0042] (Variation 2) The camera system 1 of the first embodiment described above is a camera system equipped with a retractable interchangeable lens in which the length of the lens barrel shortens when the camera is not in use. A camera according to a modification of the first embodiment is a retractable camera in which the lens barrel is non-detachably attached to the camera body. A retractable camera has a mechanism in which all or part of the lens barrel is housed within the camera body when the camera is not in use, and the lens barrel protrudes from the camera body when the camera is in use. The main difference between the collapsible camera according to Modification 2 and the retractable-tube interchangeable lens barrel of the above-described embodiment is that, in the collapsible camera, STM mounting barrel 230, AF group lens chamber 240, second group lens chamber 250, etc. are built into the camera body, fixed barrel 211 and cam barrel 212 are omitted, and first group lens chamber 220 and STM mounting barrel 230 are each moved in the optical axis direction by an actuator (not shown). Note that the cam barrel 212 may also be configured to be driven by an actuator (not shown) to move first group lens chamber 220 and STM mounting barrel 230 in the optical axis direction.

[0043] When the retractable camera is in use, the first lens group chamber 220 protrudes from the camera body, and in this state, zooming and focusing operations are performed in the same manner as in the retractable-cylinder interchangeable lens barrel 200 of the above-described embodiment. On the other hand, in a retractable camera, during retraction, the first lens group chamber 220 and the STM mounting barrel 230 are moved in the optical axis direction toward the second lens group chamber 250 by an actuator (not shown). The movement of the STM mounting barrel 230 stops midway, but the actuator (not shown) continues to drive the first lens group chamber 220 toward the STM mounting barrel 230 so as to reduce the gap between its lens holding portion 222 and the first guide plate 231 of the STM mounting barrel 230. As a result, the first lens group chamber 220 protrudes from the camera body during use, but when retracted, the amount of protrusion is reduced or almost eliminated.

[0044] (Variation 3) In the above-described embodiment, the second lens group chamber 250 is fixed, but it may be configured to be movable in the direction of the optical axis OA.

[0045] (Variation 4) In the above-described embodiment, in FIGS. 2, 3, and 7, the left side is the subject side and the right side is the imaging element side, but the left side may be the imaging element side and the right side may be the subject side.

[0046] (Variation 5) In the embodiment described above, the rack portion 242 is attached to the AF group lens chamber 240. The rack portion 242 is threaded to engage with the lead screw 271 of the AF stepping motor 270. However, instead of the rack portion 242, a nut portion threaded to engage with the lead screw 271 may be provided in the AF group lens chamber 240.

[0047] The above-described first embodiment of the present invention also includes the following aspects. (1) A lens barrel according to a first aspect includes a first lens holding member that holds a first lens, a drive source connected to the first lens holding member and that drives the first lens holding member in the optical axis direction, an attachment member to which the drive source is attached, and a guide member that guides the first lens holding member and the attachment member so that they can move in the optical axis direction. (2) In a second aspect, in the lens barrel according to the first aspect, a fixed member to which the guide member is fixed is provided, and the fixed member moves in the optical axis direction during zooming. (3) In a third aspect, the lens barrel according to the second aspect further includes a cam barrel that rotates around the optical axis during zooming, the fixed member holds other lenses included in the lens barrel, the attachment member has an attachment member cam follower that is moved in the optical axis direction by the cam barrel, and the fixed member has a fixed member cam follower that is moved in the optical axis direction by the cam barrel. (4) A fourth aspect is a lens barrel according to any one of the first to third aspects, further comprising a fixed member to which a guide member is fixed, and a cam barrel that rotates around the optical axis as a center of rotation during zooming, wherein the guide member has an axial member extending along the optical axis direction, and the fixed member has a first fixed member that fixes one end of the axial member and a second fixed member that fixes the other end of the axial member, the first fixed member having a cylindrical shape centered on the optical axis, and an attachment member arranged on its inner side, and the second fixed member is a plate member that is arranged along a direction approximately perpendicular to the optical axis and is fixed to the first fixed member. (5) In a fifth aspect, the lens barrel according to any one of the first to fourth aspects further comprises a fixed member to which a guide member is fixed, and a cam barrel that rotates around the optical axis as a center of rotation during zooming, and the attachment member has an attachment member cam follower that is moved in the optical axis direction by the cam barrel, and the attachment member moves in the optical axis direction by being guided in the optical axis direction by the guide member and by engagement between the cam barrel and the attachment member cam follower. (6) In a sixth aspect, the lens barrel according to any one of the second to fifth aspects further includes a retractable mechanism that moves at least the fixed member in the optical axis direction to shorten the overall length of the lens barrel, and the retractable mechanism moves the guide member relative to the mounting member and the first lens holding member by moving the fixed member in the optical axis direction. (7) An optical device according to a seventh aspect includes a lens barrel according to any one of the first to sixth aspects.

[0048] <Second embodiment> A second embodiment of the lens barrel will be described with reference to FIGS. 8 is a perspective view showing a lens-interchangeable camera system 1 that includes a lens barrel according to this embodiment as an interchangeable lens. The camera system 1 includes a camera body 100 and an interchangeable lens barrel 200A that is detachable from the camera body 100.

[0049] The camera body 100 is provided with a body-side lens mount 101 to which the interchangeable lens barrel 200 is detachably attached. The interchangeable lens barrel 200A is also provided with a lens-side lens mount 201 that corresponds to the body-side lens mount 101 and to which the camera body 100 is detachably attached. When the interchangeable lens barrel 200A is attached to the camera body 100, a contact group 102 made up of multiple contacts provided on the body-side lens mount 101 connects to a contact group 202 made up of multiple contacts provided on the lens-side lens mount 201. The contact groups 102 and 202 are used to supply power from the camera body 100 to the interchangeable lens barrel 200A, and to send and receive signals between the camera body 100 and the interchangeable lens barrel 200A.

[0050] An image sensor 104 that captures a subject image and outputs an image signal is provided behind a body-side lens mount 101 inside the camera body 100. Buttons 107, which serve as an input device, are provided above the camera body 100. A user uses the buttons 107 to give instructions to the camera body 100 for shooting, setting shooting conditions, and the like.

[0051] The interchangeable lens barrel 200A of this embodiment has a fixed barrel 211 composed of first and second cylindrical members 211a and 211b that cover the outer periphery of the interchangeable lens barrel 200A, and a zoom ring 205 disposed between the first and second cylindrical members 211a and 211b. The interchangeable lens barrel 200A is a so-called manual zoom lens, configured so that the focal length can be changed by the user manually operating the zoom ring 205. When the user rotates the zoom ring 205, the focal length of the interchangeable lens barrel 200A changes continuously toward the wide-angle end or the telephoto end. In other words, the focal length of the interchangeable lens barrel 200A can be set arbitrarily between the wide-angle end position and the telephoto end position by operating the zoom ring 205.

[0052] As will be described in detail later, the interchangeable lens barrel 200A is a retractable barrel that can be in an extended state in which a lens inner barrel 203, which holds all or part of the photographic optical system, extends from a fixed barrel 211, and in a retracted state in which the lens inner barrel is housed within the fixed barrel 211. In Figure 8, the lens inner barrel 203 in the extended state is shown by a dashed line.

[0053] The interchangeable lens barrel 200A is switched between an extended state and a retracted state by operating the retraction release button 204 and the zoom ring 205. That is, when the interchangeable lens barrel 200A is in the extended state, the inner barrel 203 extends, i.e., protrudes, from the fixed barrel 211, and the overall length L of the interchangeable lens barrel 200A is L1. In this extended state, the interchangeable lens barrel 200A can form a good subject image on the image sensor 104, and the camera system 1 is ready for photography. To switch from the extended state to the retracted state, the zoom ring 205 is rotated while pressing the retraction release button 204, thereby rotating the zoom ring 205 to a rotation angle position greater than the rotation position for moving the focal length of the lens to the wide-angle end. This further rotation retracts the inner barrel 203 into the inner periphery of the fixed barrel 211, and the interchangeable lens barrel 200A enters the retracted state. The lens barrel length L2 in this retracted state is shorter than the length L1 in the extended state, and the camera system 1 is in a state where photography is not possible. When the focal length of the interchangeable lens barrel 200A is between the wide-angle end and the telephoto end, rotation of the zoom ring 205 to a rotation angle position greater than the wide-angle end or the telephoto end is prohibited unless the zoom ring 205 is rotated while pressing the retraction release button 204. In other words, the retraction release button 204 is part of a configuration that performs a mechanical locking function that physically prohibits transitioning from the extended state to the retracted state.

[0054] On the other hand, once the interchangeable lens barrel 200A is in the retracted state, the zoom ring 205 cannot be rotated to a rotation angle position between the wide-angle end and the telephoto end unless the retraction release button 204 is also pressed. In other words, the retraction release button 204 is part of a configuration that performs a mechanical locking function that physically prohibits transitioning from the retracted state to the extended state.

[0055] Thus, in order to bring the interchangeable lens barrel 200A from the extended state into the retracted state, the user must rotate the zoom ring 205, which is in a rotation operation position corresponding to the wide-angle end, to an even larger rotation angle position while pressing the retraction release button 204. Conversely, in order to bring the interchangeable lens barrel 200A from the retracted state into the extended state, the user must rotate the zoom ring 205 to a rotation angle position between the wide-angle end and the telephoto side while pressing the retraction release button 204.

[0056] 9-12 are cross-sectional views of a portion of the interchangeable lens barrel 200A in the extended state. Figures 9 and 10 are diagrams showing a cross section in which the main guide bar 261 and sub-guide bar 262 are visible, and Figures 11 and 12 are diagrams showing a cross section in which the main guide bar 261 and AF stepping motor 270 are visible. Figures 9 and 11 show a state in which the AF group lens 241 has moved to a position where it focuses on infinity, and Figures 10 and 12 show a state in which the AF group lens 241 has moved to a position where it focuses on a close distance. Figures 13-15 are exploded views of a portion of the interchangeable lens barrel 200A.

[0057] As shown in Figures 9-12, the interchangeable lens barrel 200A has a fixed barrel 211, a zoom ring 205, a cam barrel 212 that fits into the inner circumference of the fixed barrel 211, a first group lens chamber 220 that fits into the inner circumference of the cam barrel 212, a stepping motor (STM) mounting barrel 230, an AF group lens chamber 240, and a second group lens chamber 250. In this embodiment, when the first lens group chamber 220 is in the extended state, it protrudes from the fixed barrel 211 toward the subject, i.e., corresponds to the inner barrel 203 in FIG. 8, which extends. Also, in FIGS. 9-12 and 14-17, the left side is the subject side and the right side is the image sensor side. In FIG. 13, the right side is the subject side and the left side is the image sensor side. Note that another lens may be located closer to the subject than the first lens group chamber 220. Also, another lens may be located closer to the image sensor than the second lens group chamber 250.

[0058] 9 and 13, as described above, the zoom ring 205 is disposed between the first and second cylindrical members 211a and 211b of the fixed barrel 211, and the zoom ring 205 can be rotated relative to the first cylindrical member 211a and the second cylindrical member 211b. The zoom ring 205 is engaged with the cam barrel 212 by a linear key, so that the zoom ring 205 can rotate integrally with the cam barrel 212 and move linearly relative to it. In this way, the cam barrel 212 is rotated by the rotation of the zoom ring 205 shown in FIG. 8, and has a cam groove 212a on its inner periphery.

[0059] 9 and 13, the first lens group chamber 220 has a cylindrical tube portion 221 and a hollow, disk-like lens holding portion 222 that holds the first lens group 223 on the subject side of the tube portion 221. The lens holding portion 222 is fixed to the subject side end of the tube portion 221. A cam follower 221a that fits into a cam groove 212a of the cam tube 212 is provided on the outer periphery of the tube portion 221. Rotation of the tube portion 221 around the optical axis is restricted by a linear guide member (not shown), and when the cam tube 212 rotates, the tube portion 221 is moved linearly in the optical axis direction by the engagement between the cam groove 212a and the cam follower 221a and the linear guide member.

[0060] A main guide bar 261 and a sub-guide bar 262 are attached to the lens holder 222 to guide the STM mounting barrel 230 and the AF group lens chamber 240 in the optical axis OA direction. The main guide bar 261 and the sub-guide bar 262 are each axially oriented along the optical axis OA direction and are disposed near positions facing each other across the optical axis OA. Their ends on the subject side are attached to the lens holder 222, and they each extend along the optical axis OA toward the image sensor side (see FIGS. 13-15). As shown in FIG. 9, a plate-shaped main guide bar adjustment plate 263 is attached to the right end of the barrel 221 of the first group lens chamber 220, i.e., the end on the image sensor side. The end of the main guide bar 261 on the image sensor side is attached to the main guide bar adjustment plate 263. The main guide bar adjusting plate 263 is formed with a main guide bar fixing hole to which an end of the main guide bar 261 is fixed, and a screw hole for fixing the main guide bar adjusting plate 263 to the cylindrical portion 221. The main guide bar adjusting plate 263 has a substantially triangular shape when viewed from the optical axis OA direction, with one side on the outer periphery curved in an arc shape to fit along the outer periphery of the cylindrical portion 221. One end of the main guide bar 261 is supported by the lens holding portion 222, and the other end is supported by the main guide bar adjusting plate 263. The angle of the main guide bar 261 with respect to the optical axis OA can be adjusted by adjusting the attachment position of the main guide bar adjusting plate 263 to the cylindrical portion 221. The end of the sub guide bar 262 on the imaging element side is not supported, i.e., is not fixed.

[0061] The STM mounting barrel 230 is a member held movably in the optical axis OA direction within the first lens group chamber 220 via a main guide bar 261 and a sub-guide bar 262, and as shown in FIGS. 13-15 , an AF stepping motor 270 is attached to it. As shown in FIGS. 9 and 13 , the STM mounting barrel 230 has first and second guide plates 231 and 232 spaced apart in the optical axis OA direction, a connecting portion 233 connecting the first and second guide plates 231 and 232 to each other, and an STM mounting portion 234 fixed to the first guide plate 231. The AF stepping motor 270 is fixed to the STM mounting portion 234 with screws or the like. The first guide plate 231 has an insertion hole 231a through which the main guide bar 261 is inserted and an insertion hole 231b through which the sub-guide bar 262 is inserted. The second guide plate 232 also has an insertion hole 232a through which the main guide bar 261 is inserted. When viewed from the direction of the optical axis OA, the insertion holes 231a, 232a are circular and have substantially the same shape as the outer circumferential surface of the main guide bar 261. When viewed from the direction of the optical axis OA, the insertion hole 231b is elliptical or U-shaped extending along the normal direction of a circle centered on the optical axis OA, and is in contact with two points on the outer circumferential surface of the sub-guide bar 262. In this way, the STM mounting tube 230 is fitted to the main guide bar 261 so as to be able to move linearly along the main guide bar 261, and is prevented by the sub-guide bar 262 from rotating about the main guide bar 262 on a plane perpendicular to the optical axis.

[0062] The STM mounting barrel 230 is slidable along the optical axis OA direction relative to the main guide bar 261 and the sub guide bar 262, and is guided by the main guide bar 261 and the sub guide bar 262 to move along the optical axis OA direction relative to the first group lens chamber 220.

[0063] As shown in FIG. 9 , a second lens group chamber 250 is disposed on the imaging element side of the first lens group chamber 220 and the STM mounting barrel 230. The second lens group chamber 250 is a lens group that holds a second lens group 251. In this embodiment, the position of the second lens group chamber 250 in the optical axis direction within the interchangeable lens barrel 200A is fixed. Meanwhile, the first lens group chamber 220 is movable in the optical axis direction, and in the retracted state, moves toward the second lens group chamber 250. As shown in FIGS. 16 and 17 , when changing from the extended state to the retracted state, the first lens group chamber 220 moves toward the second lens group chamber 250, and in the retracted state, at least a portion of the second lens group chamber 250 is positioned closer to the subject than a main guide bar adjustment plate 263 located at the rear end of the first lens group chamber 220. At the front end of the second lens group chamber 250, i.e., the end on the subject side, there is provided an abutment portion 252 that abuts against the rear end face of the second guide plate 232 of the STM mounting barrel 230, i.e., the end face on the image sensor side, in the retracted state, as will be described later. As shown in Figures 9-12, in the extended state, the abutment portion 252 is spaced apart from the rear end face of the second guide plate 232 of the STM mounting barrel 230.

[0064] 9, a coil spring 281 arranged coaxially with the main guide bar 261 and a coil spring 282 arranged coaxially with the sub-guide bar 262 are disposed between the first guide plate 231 of the STM mounting barrel 230 and the lens holding portion 222 of the first lens group chamber 220. The coil springs 281 and 282 constantly urge the lens holding portion 222 in a direction separating the first guide plate 231 from the first guide plate 261. As a result of the constant urging of the coil springs 281 and 282, the STM mounting barrel 230 is brought into contact with the main guide bar adjusting plate 263 of the first lens group chamber 220 or the contact portion 252 of the second lens group chamber 250, thereby stabilizing the STM mounting barrel 230.

[0065] The AF stepping motor 270 has an output shaft directly connected to a lead screw 271, and is activated at least during focusing operation to rotate the lead screw 271. The AF stepping motor 270 may also be activated during zooming operation or retraction / extension of the barrel.

[0066] 9, the AF group lens chamber 240 holds an AF group lens 241, and the AF group lens chamber 240 is held in the first group lens chamber 220 via a main guide bar 261 and a sub guide bar 262. The AF group lens 241 is a focusing lens that moves when focusing, and also constitutes a zooming lens in combination with the first group lens 223. That is, the AF group lens 241 is moved independently in the direction of the optical axis OA by an AF stepping motor 270 during focusing, and is moved together with the first group lens 223 in the direction of the optical axis OA during zooming, as will be described in detail later. The AF group lens 241 does not have to be a focusing lens, and may be a lens that moves during zooming or retraction / extension.

[0067] The AF group lens chamber 240 is provided with insertion holes 240a and 240b through which the main guide bar 261 is inserted, and a semicircular hole 240c through which the sub guide bar 262 is inserted. The AF group lens chamber 240 is guided by the main guide bar 261 and the sub guide bar 262 so as to be slidable along the optical axis OA direction.

[0068] 11 and 13, a rack portion 242 is attached to the AF group lens chamber 240. A thread is formed in the rack portion 242 to engage with a lead screw 271 of the AF stepping motor 270. In this way, the AF stepping motor 270 attached to the STM mounting barrel 230 and the AF group lens chamber 240 are connected to each other by the engagement of the lead screw 271 and the rack portion 242. When the lead screw 271 of the AF stepping motor 270 is driven to rotate, the rack portion 242 moves in the optical axis direction while engaging with the lead screw 271. Because the rack portion 242 is attached to the AF group lens chamber 240 and the AF group lens chamber 240 is guided linearly by the main guide bar 261 and the sub guide bar 262, movement of the rack portion 242 in the optical axis direction also moves the AF group lens chamber 240 along the optical axis direction.

[0069] As described above, in the extended state, STM mounting barrel 230 is held in a position where it abuts main guide bar adjustment plate 263 by coil springs 281, 282, and therefore the relative position between STM mounting barrel 230 and first lens group housing 220 remains unchanged. Therefore, in the extended state, when AF stepping motor 270 is driven during a focusing operation, AF group lens housing 240 is driven along the optical axis OA relative to first lens group 223 and second lens group 251 (described later) between the infinity position shown in Fig. 11 and the close position shown in Fig. 12, changing the focus position.

[0070] ---Operation of each part of the interchangeable lens barrel 200A in the extended state--- First, the zooming operation of interchangeable lens barrel 200A will be described. In Fig. 9, when interchangeable lens barrel 200A is in the extended state, rotating zoom ring 205 rotates cam barrel 212, causing first lens group chamber 220 and STM mounting barrel 230 to move together along optical axis OA, thereby performing a magnification change operation. Simultaneously with this magnification change operation, AF stepping motor 270 moves AF group lens 241 along optical axis OA relative to STM mounting barrel 230, preventing fluctuations in the focal position, i.e., fluctuations in the focus position.

[0071] Next, the focusing operation of the interchangeable lens barrel 200A will be described. When the interchangeable lens barrel 200A is in the extended state, driving the AF stepping motor 270 shown in FIG. 11 drives the AF group lens housing 240 along the optical axis OA relative to the STM mounting barrel 230, as described above. The relative position between the STM mounting barrel 230 and the first lens group housing 220 remains unchanged regardless of the rotational position of the zoom ring 205. Therefore, when the AF stepping motor 270 is driven, the AF group lens housing 240 drives along the optical axis OA relative to the first lens group housing 220, changing the relative distance between the AF group lens 241 and the first and second lens groups 223 and 251, and changing the focus position.

[0072] In the extended and retracted states, the AF group lens 241 and the second group lens 251 do not interfere with each other, regardless of the focal length or the in-focus position.

[0073] ---When transitioning from an extended state to a compressed state--- Next, the retraction operation of the interchangeable lens barrel 200A will be described. To move from the extended state to the retracted state, when the zoom ring 205 is rotated in a predetermined direction while pressing the retraction release button 204 shown in Figure 8, the first lens group chamber 220 and STM mounting barrel 230 shown in Figure 9 move together toward the second lens group chamber 250, and eventually the second guide plate 232 of the STM mounting barrel 230 comes into contact with the abutment portion 252 of the second lens group chamber 250. Note that when the STM mounting barrel 230 moves as described above, the AF group lens chamber 240, which is connected to the AF stepping motor 270 attached to the STM mounting barrel 230, also moves.

[0074] Then, when the zoom ring 205 is further rotated in the predetermined direction while pressing the retraction release button 204, the STM mounting barrel 230 comes to a stop as its second guide plate 232 abuts against the abutment portion 252 of the second lens group housing 250, and only the first lens group housing 220 moves further in the same direction by a predetermined amount, thereby completing the retraction operation. Note that when the STM mounting barrel 230 stops, the AF group lens housing 240 also stops due to the connection between the AF stepping motor 270 and the AF group lens housing 240.

[0075] 16 or 17, when the retracted barrel operation is completed, the distance between the lens holder 222 of the first lens group chamber 220 and the first guide plate 231 of the STM mounting barrel 230 becomes smaller than the distance in the extended state, i.e., the distance between the lens holder 222 of the first lens group chamber 220 and the second lens group chamber 250 becomes smaller. In this state, the first lens group chamber 220 is housed within the fixed barrel 211.

[0076] 16 shows the retracted state when the AF group lens 241 is at the infinity position, and Fig. 17 shows the retracted state when the AF group lens 241 is at the closest position. As is clear from Fig. 16 and Fig. 17, in the retracted state, the distance between the lens holding section 222 of the first lens group chamber 220 and the first guide plate 231 of the STM mounting barrel 230 is smaller than the distance in the extended state, and since the AF group lens 241 also stops when the STM mounting barrel 230 stops, there is no interference between the AF group lens 241 and the second group lens 251 regardless of the position of the AF group lens 241.

[0077] ---When transitioning from a compressed state to an extended state--- Next, the extension operation of the interchangeable lens barrel 200A will be described. To change from the retracted state to the extended state, when the zoom ring 205 is rotated in the opposite direction to that used during retraction while pressing the retraction release button 204 shown in Fig. 8, the first lens group chamber 220 shown in Fig. 16 moves in the opposite direction to that used during retraction, i.e., in the direction away from the second lens group chamber 250, and returns to the extended state shown in Fig. 9 or 10.

[0078] According to the second embodiment described above, the following advantageous effects can be obtained. (1) Interchangeable lens barrel 200A includes AF group lens chamber 240 that holds AF group lens 241, AF stepping motor 270 that is connected to AF group lens chamber 240 and drives AF group lens chamber 240 in the optical axis direction, STM mounting cylinder 230 to which AF stepping motor 270 is attached and that is movable in the optical axis OA direction together with AF stepping motor 270, and coil spring 281 that biases STM mounting cylinder 230 in one direction along the optical axis direction. As a result, the STM mounting barrel 230 is always biased in one direction, thereby stabilizing its position within the interchangeable lens barrel 200A (specifically, the position of the STM mounting barrel 230 relative to the first lens group chamber 220). Furthermore, during retraction, the STM mounting barrel 230 can be pushed from the other direction so that the coil spring 281 is shorter than when the barrel is extended, allowing other components to be placed in the space where the STM mounting barrel 230 was located during extension. Specifically, in the above-described embodiment, the first lens group chamber 220 moves toward the imaging element together with the STM mounting barrel 230, causing the second lens group chamber 250 to press the STM mounting barrel 230 in a direction that moves it toward the subject within the first lens group chamber 220. Furthermore, as the position of the STM mounting barrel 230 within the first lens group chamber 220 moves toward the subject, a portion of the second lens group chamber 250 can be housed inside the first lens group chamber 220, thereby shortening the barrel length L. This allows the interchangeable lens barrel 200A to be made more compact. In the above-described embodiment, the position of the STM mounting barrel 230 relative to the first lens group chamber 220 is changed between when the barrel is retracted and when it is extended. However, the position of the STM mounting barrel 230 relative to the first lens group chamber 220 may also be changed depending on the focal length state and the shooting distance.

[0079] (2) The interchangeable lens barrel 200A includes a first lens group 223 arranged at a position facing the object side of the AF group lens 241, and a first lens group housing 220 that holds the first lens group 223 and is movable in the direction of the optical axis OA together with the first lens group 223. The interchangeable lens barrel 200A has a coil spring 281 arranged between the first lens group housing 220 and the STM mounting barrel 230. The first lens group housing 220 is biased by the coil spring 281 in one direction along the direction of the optical axis OA, in the opposite direction to the STM mounting barrel 230. This allows the position of the STM mounting barrel 230 relative to the first lens group chamber 220 in the optical axis OA direction to be stably maintained. By stabilizing the position of the STM mounting barrel 230 relative to the first lens group chamber 220, the position of the AF group lens 241, which is held by the STM mounting barrel 230 via the AF stepping motor 270, in the optical axis OA direction is also stabilized, preventing deterioration of the optical performance of the interchangeable lens barrel 200A. Furthermore, since the first lens group chamber 220 and the STM mounting barrel 230 can be brought closer together during retraction so that the coil spring 281 is shorter than when the barrel is extended, the barrel length L in the retracted state can be shortened. This allows the interchangeable lens barrel 200A to be made more compact. The interchangeable lens barrel 200A can be changed from the extended state to the retracted state by the user manually operating the zoom ring. Here, if the change from the extended barrel state to the retracted barrel state is performed using the driving force of a motor or the like, it is necessary to provide a motor or the like inside the interchangeable lens barrel 200A that is capable of outputting a large driving force that can resist the biasing force of the coil spring 281, which would result in an increase in the size of the interchangeable lens barrel 200A. On the other hand, according to the above-described embodiment, it is possible to manually resist the biasing force of the coil spring 281, so there is no need to provide a motor that can output a large driving force, and it is possible to avoid an increase in the size of the interchangeable lens barrel 200A.

[0080] (3) The interchangeable lens barrel 200A includes a main guide bar 261 that guides the AF group lens chamber 240 and the STM mounting barrel 230 so that they can move in the direction of the optical axis OA. The main guide bar 261 is a guide bar that extends substantially parallel to the optical axis OA. The STM mounting cylinder 230 has a pair of first and second guide plates 231, 232 that are spaced apart from each other and have insertion holes 231a, 232a through which the main guide bar 261 passes, and a connecting portion 233 that connects the pair of first and second guide plates 231, 232. The AF group lens chamber 240 has insertion holes 240a and 240b between the pair of first and second guide plates 231 and 232 of the STM mounting barrel 230, through which the main guide bar 261 passes. As a result, when the STM mounting barrel 230 moves in the direction of the optical axis OA, the AF group lens chamber 240 also moves integrally with the STM mounting barrel 230 in the same direction due to the connection between the AF stepping motor 270 and the AF group lens chamber 240, and the AF group lens chamber 240 can be moved relative to the STM mounting barrel 230 by driving the AF stepping motor 270. In other words, movement of the AF group lens chamber 240 in the direction of the optical axis OA during zooming is achieved by movement of the first lens chamber 220 (movement of the first lens chamber 220 due to cam engagement between the cam grooves 212a of the cam barrel 212 and the cam followers 221a of the first lens chamber 220), and movement of the AF group lens chamber 240 in the direction of the optical axis OA during focusing is achieved by the driving force of the AF stepping motor 270. Therefore, even if the focus position changes during zooming, it is possible to correct the focus position by performing a focusing operation during the zooming operation. Therefore, the user can suppress deviation of the in-focus position by performing a focusing operation while performing a zooming operation.

[0081] (4) The interchangeable lens barrel 200A includes a first group lens 223 arranged at a position facing the object side of the AF group lens 241, a first group lens chamber 220 that holds the first group lens 223 and is movable together with the first group lens 223 in the direction of the optical axis OA, and a main guide bar 261 that is fixed to the first group lens chamber 220 and guides the AF group lens chamber 240 and the STM mounting barrel 230 movably in the direction of the optical axis. This allows the linear guide members of the AF group lens chamber 240 and the STM mounting barrel 230 to be used together, thereby reducing the number of parts. Furthermore, by holding the main guide bar 261 accurately relative to the first lens group chamber 220, the AF group lens chamber 240 and the STM mounting barrel 230 can be moved accurately. Therefore, highly accurate movement is easily possible compared to providing separate linear guide members for the AF group lens chamber 240 and the STM mounting barrel 230 and holding them accurately.

[0082] (5) The interchangeable lens barrel 200A includes a first group lens 223 that is arranged at a position facing the object side of the AF group lens 241, and a first group lens chamber 220 that holds the first group lens 223 and is movable in the direction of the optical axis OA together with the first group lens 223. The first group lens chamber 220 includes a main guide bar adjustment plate 263 against which the STM mounting cylinder 230 is biased in one direction along the direction of the optical axis OA by a coil spring 281. Therefore, the STM mounting barrel 230 is biased by the coil spring 281 against the main guide bar adjustment plate 263 of the first lens group chamber 220, so that in the extended state it moves integrally with the first lens group chamber 220, and during retracted barrel operation it can move relative to the first lens group chamber 220, allowing the interchangeable lens barrel 200A to be made smaller.

[0083] (6) Interchangeable lens barrel 200A has contact portion 252 of second lens group chamber 250, the distance from which to STM mounting barrel 230 changes in the direction of optical axis OA. Contact portion 252 of second lens group chamber 250 can move STM mounting barrel 230 in the direction opposite to the one direction described above against the biasing force of coil spring 281. This allows the distance between first lens group chamber 220 and second lens group chamber 250 to be shortened, and therefore the barrel length L can be shortened.

[0084] The following modifications are also within the scope of the present invention, and one or more of the modifications may be combined with the second embodiment described above. (Variation 1) The sub guide bar 262 and the coil spring 282 attached to this sub guide bar 262 may be omitted. Also, another DC motor or ultrasonic motor may be used instead of the AF stepping motor 270. Furthermore, with regard to the lens groups, the number of lenses constituting the first lens group 223, the number of lenses constituting the AF group lens 241, and the number of lenses constituting the second lens group 251 are not limited to the numbers shown in the illustration, and may be increased or decreased.

[0085] (Variation 2) The camera system 1 of the above embodiment is a camera system equipped with a retractable interchangeable lens whose lens barrel shortens when the camera is not in use. A camera according to a modified embodiment is a retractable camera in which the lens barrel is irremovably attached to the camera body. A retractable camera has a mechanism in which all or part of the lens barrel is housed within the camera body when the camera is not in use, and the lens barrel protrudes from the camera body when the camera is in use. The main difference between the retractable camera according to Variation 2 and the retractable-tube interchangeable lens barrel of the above-described embodiment is that, in the retractable camera, as shown in FIG. 9, the STM mounting barrel 230, the AF group lens chamber 240, the second group lens chamber 250, etc. are built into the camera body, the fixed barrel 211 and the cam barrel 212 are omitted, and the first group lens chamber 220 is moved in the optical axis direction by an actuator (not shown).

[0086] When the retractable camera is in use, the first lens group chamber 220 protrudes from the camera body, and in this state, zooming and focusing operations are performed in the same manner as in the retractable-cylinder interchangeable lens barrel 200A of the above-described embodiment. On the other hand, in a retractable camera, during retraction, the first lens group chamber 220 is moved in the optical axis direction toward the second lens group chamber 250 by an actuator (not shown). As the first lens group chamber 220 moves, the STM mounting barrel 230 also moves in the same direction and abuts against the abutment portion 252 of the second lens group chamber 250, preventing further movement. Continued driving by the actuator (not shown) moves the first lens group chamber 220 closer to the STM mounting barrel 230 so as to reduce the gap between its lens holding portion 222 and the first guide plate 231 of the STM mounting barrel 230. As a result, the first lens group chamber 220 protrudes from the camera body during use, but when retracted, the amount of protrusion is reduced or almost eliminated.

[0087] (Variation 3) In the above-described embodiment, the second lens group chamber 250 is fixed, but it may be configured to be movable in the direction of the optical axis OA.

[0088] (Variation 4) In the above-described embodiment, in FIGS. 9-12, 16, and 17, the left side is the subject side and the right side is the image sensor side, but the left side may be the image sensor side and the right side may be the subject side.

[0089] (Variation 5) In the embodiment described above, the rack portion 242 is attached to the AF group lens chamber 240. The rack portion 242 is threaded to engage with the lead screw 271 of the AF stepping motor 270. However, instead of the rack portion 242, a nut portion threaded to engage with the lead screw 271 may be provided in the AF group lens chamber 240.

[0090] The above-described second embodiment of the present invention also includes the following aspects. (1) A lens barrel according to an eighth aspect includes a first lens holding member that holds at least one first lens, a drive source connected to the first lens holding member and that drives the first lens holding member in the optical axis direction, an attachment member to which the drive source is attached and that is movable in the optical axis direction together with the drive source, and a biasing member that biases the attachment member in one direction along the optical axis direction. (2) A ninth aspect is a lens barrel according to the eighth aspect, which includes a second lens arranged at a position facing the object side or image plane side of the first lens, and a second lens holding member that holds the second lens and is movable together with the second lens in the optical axis direction, and a biasing member is arranged between the second lens holding member and the mounting member, and the second lens holding member is biased by the biasing member in one direction along the optical axis direction, in the opposite direction to the mounting member. (3) A tenth aspect is a lens barrel according to the eighth or ninth aspect, further comprising a guide member that guides the first lens holding member and the mounting member so that they can move in the optical axis direction, the guide member being a guide bar extending substantially parallel to the optical axis, the mounting member having a pair of guide plates spaced apart from each other and each having a guide hole through which the guide bar passes, and a connecting portion that connects the pair of guide plates, and the first lens holding member having a guide hole through which the guide bar passes between the pair of guide plates. (4) An eleventh aspect is a lens barrel according to any one of the eighth to tenth aspects, which comprises a second lens arranged at a position facing the object side or image plane side of the first lens, a second lens holding member that holds the second lens and is movable together with the second lens in the optical axis direction, and a guide member that is fixed to the second lens holding member and guides the first lens holding member and the mounting member so that they can move in the optical axis direction. (5) In a twelfth aspect, in the lens barrel according to any one of the eighth to eleventh aspects, the drive source has a motor and a lead screw rotated by the motor, and the first lens holding member has a meshing portion that meshes with the lead screw. (6) A thirteenth aspect is a lens barrel according to any one of the eighth to twelfth aspects, comprising a second lens arranged at a position facing the object side or image plane side of the first lens, and a second lens holding member that holds the second lens and is movable together with the second lens in the optical axis direction, and the second lens holding member has a contact point where the mounting member is urged in one direction along the optical axis direction by a urging member and is brought into contact. (7) In a fourteenth aspect, in the lens barrel according to any one of the eighth to thirteenth aspects, a limiting member is provided whose distance from the mounting member changes in the optical axis direction, and the limiting member is capable of moving the mounting member in a direction opposite to one direction against the biasing force of the biasing member. (8) In a fifteenth aspect, in the lens barrel according to the fourteenth aspect, the limiting member is a lens holding member that holds a third lens, and the distance between the limiting member and the mounting member becomes small during retraction or contraction. (9) An optical device according to a sixteenth aspect includes a lens barrel according to any one of the eighth to fifteenth aspects.

[0091] Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments that are conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0092] The disclosures of the following priority applications are incorporated herein by reference: Japanese Patent Application No. 2016-116105 (filed June 10, 2016) Japanese Patent Application No. 2016-116106 (filed June 10, 2016) [Explanation of symbols]

[0093] 1; camera system, 100; camera body, 200, 200A; interchangeable lens barrel, 212; cam barrel, 220; first lens group chamber, 221; barrel portion, 221a, 233a; cam follower, 222; lens holding portion, 223; first lens group, 230; STM mounting barrel, 231; first guide plate, 232; second guide plate, 233; connecting portion, 240; AF group lens chamber, 241; AF group lens, 242; rack portion, 250; second lens group chamber, 251; second lens group, 252; abutment portion, 261; main guide bar, 263; main guide bar adjustment plate, 270; AF stepping motor, 271; lead screw, 281, 282; coil spring

Claims

1. A first lens; a first barrel that holds the first lens and has a first cam follower; A second lens; a second frame that holds the second lens; a focus lens disposed between the first lens and the second lens and facing each of the first lens and the second lens; a focus lens frame that holds the focus lens; an actuator that drives the focus lens; a third cylinder that holds the actuator and has a second cam follower; a cam barrel having a first cam groove that engages with the first cam follower and a second cam groove that engages with the second cam follower, the cam barrel being rotatable around the optical axis; Equipped with at least a portion of the focus lens frame is disposed on the inner peripheral side of the third barrel, the third barrel does not directly hold the focus lens or the focus lens frame, When the cam barrel rotates, the first barrel and the third barrel move along different trajectories in the optical axis direction due to the first cam groove and the second cam groove of the cam barrel, the actuator and the focus lens frame move in the optical axis direction in accordance with the movement of the third barrel in the optical axis direction, and the actuator moves the focus lens frame in the optical axis direction relative to the third barrel. Lens barrel.

2. 2. The lens barrel according to claim 1, The cam barrel rotates in response to a zoom operation. Lens barrel.

3. 3. The lens barrel according to claim 1, the actuator drives the focus lens relative to the third barrel. Lens barrel.

4. The lens barrel according to claim 3, an engagement portion of the focus lens frame and a shaft of the actuator are in contact with each other; Lens barrel.

5. The lens barrel according to claim 4, the engaging portion is located on the inner peripheral side of the third cylinder, Lens barrel.

6. The lens barrel according to claim 4 or 5, an end of a shaft of the actuator contacts at least a portion of the third cylinder; Lens barrel.

7. The lens barrel according to any one of claims 4 to 6, The engaging portion has a thread that engages with the shaft. Lens barrel.

8. The lens barrel according to any one of claims 4 to 7, a nut having threads that mate with the shaft; Lens barrel.

9. The lens barrel according to any one of claims 1 to 8, a guide shaft that guides the focus lens frame and the third barrel so that they can move in the optical axis direction, Lens barrel.

10. The lens barrel according to any one of claims 1 to 8, The third cylinder is a guide shaft that guides the focus lens frame and the third barrel so that they can move in the optical axis direction; a flange portion at an end portion on the object side in the optical axis direction; and The flange portion has a hole through which the guide shaft is inserted. Lens barrel.

11. The lens barrel according to claim 10, the focus lens frame is disposed closer to the image plane than the flange portion; Lens barrel.

12. The lens barrel according to any one of claims 4 to 8, the first barrel has a guide shaft that guides the focus lens frame and the third barrel so that they can move in the optical axis direction; the focus lens frame has the engaging portion that engages with a shaft portion of the actuator and a hole portion through which the guide shaft is inserted, At least a portion of the guide shaft, the engaging portion, and the hole portion are disposed on the inner peripheral side of the third cylinder. Lens barrel.

13. The lens barrel according to any one of claims 9 to 11, One of the guide shafts is supported by the first cylinder. Lens barrel.

14. The lens barrel according to claim 13, the other of the guide shafts is supported by an adjustment plate, The adjustment plate is fixed to the first cylinder. Lens barrel.

15. The lens barrel according to any one of claims 9 to 11, At least a portion of the guide shaft is disposed on the inner peripheral side of the third cylinder. Lens barrel.

16. The lens barrel according to any one of claims 1 to 15, The third barrel does not directly hold a lens or a lens holding frame. Lens barrel.

17. The lens barrel according to any one of claims 1 to 16, Equipped with a retractable mechanism, Lens barrel.

18. A lens barrel comprising the lens barrel according to any one of claims 1 to 17. Imaging device.

Images