Lens barrel and imaging device

Abstract

To provide a lens barrel that can be downsized.SOLUTION: A lens barrel 2 comprises: an optical system having a first lens group L1, a second lens group L2, a third lens group L3, a fourth lens group L4, a fifth lens group L5, and a sixth lens group L6 in order from an object side; a movable cylinder 100 that moves along an optical axis with a change in focal length; and a first driving portion 5M and a second driving portion 6M in the movable cylinder. The fifth lens group moves along the optical axis to the movable cylinder by the first driving portion when focusing, and the sixth lens group moves along the optical axis to the movable cylinder by the second driving portion when focusing. The movement amount of the fifth lens group to the movable cylinder when the focal length is changed to a telephoto end in a first state where the fifth lens group is arranged closest to a subject side with a wide angle end is less than the movement amount of the fifth lens group to the movable cylinder when the focal length is changed from the wide angle end to the telephoto end in a second state where the fifth lens group is arranged closer to an image surface side than in the first state with the wide angle end.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Conventionally, various proposals have been made regarding a lens barrel that is provided with a focus lens and that is driven by a motor (see, for example, Patent Document 1). Furthermore, further miniaturization of the lens barrel is desired. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-49334 Summary of the Invention

[0004] The lens barrel of the first aspect comprises an optical system having, in order from the object side, a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group; a movable barrel that moves along the optical axis by changing the focal length; a first drive unit provided on the movable barrel; and a second drive unit provided on the movable barrel, wherein the fifth lens group moves along the optical axis relative to the movable barrel by the first drive unit during focusing, and the sixth lens group moves along the optical axis relative to the movable barrel by the second drive unit during focusing, and the amount of movement of the fifth lens group with respect to the movable barrel when the focal length is changed to the telephoto end in a first state in which the fifth lens group is located closest to the subject at the wide-angle end is smaller than the amount of movement of the fifth lens group with respect to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end in a second state in which the fifth lens group is located closer to the image plane at the wide-angle end than in the first state.

[0005] The lens barrel of the second aspect comprises an optical system having, in order from the object side, a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group; a movable barrel that moves along the optical axis by changing the focal length; a first drive unit provided on the movable barrel; and a second drive unit provided on the movable barrel, wherein the fifth lens group moves relative to the movable barrel along the optical axis by the first drive unit during focusing, and the sixth lens group moves relative to the movable barrel along the optical axis by the second drive unit during focusing, and wherein in a first state in which the fifth lens group is positioned closest to the subject at the wide-angle end, the amount of movement of the fifth lens group with respect to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end is smaller than the amount of movement of the sixth lens group with respect to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end in the first state.

[0006] The lens barrel of the third aspect comprises an optical system having, in order from the object side, a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group; a movable barrel that moves along the optical axis as the focal length is changed; a first drive unit provided on the movable barrel; and a second drive unit provided on the movable barrel, wherein the fifth lens group moves along the optical axis relative to the movable barrel toward the image plane during focusing by the first drive unit, and the sixth lens group moves along the optical axis relative to the movable barrel toward the image plane during focusing by the second drive unit, and wherein the amount of movement of the fifth lens group, which is located closest to the object when the focal length is changed, is smaller than the amount of movement of the sixth lens group, which is located closest to the object when the focal length is changed.

[0007] The imaging device of the fourth aspect is configured to include the above-described lens barrel. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a conceptual diagram of a camera 1 configured by attaching a lens barrel 2 according to an embodiment to a camera body 3. FIG. [Figure 2]2 is a perspective view of an inner cam cylinder 83 of the lens barrel 2 and a cylinder member disposed on the inner diameter side thereof. FIG. [Figure 3] 2. FIG. 3 is a perspective view of the inner cam cylinder 83 removed from FIG. 2 and seen from the opposite side to FIG. [Figure 4] 4 is a diagram showing only the drive mechanism for the fifth group frame 50, with the motor moving barrel 100 removed from FIG. 3. FIG. [Figure 5] 10A and 10B are diagrams illustrating the movement states of the fifth lens group L5 and the sixth lens group L6, where (a) is at the wide-angle end zoom position, and (b) is at the telephoto end zoom position. [Figure 6] 10A and 10B are diagrams illustrating the movement amounts of the fifth lens group L5, the sixth lens group L6, and the motor-driven barrel 100 when the focal length is changed from the wide-angle end (W) to the telephoto end (T). DETAILED DESCRIPTION OF THE INVENTION

[0009] 1 is a conceptual diagram of a camera 1 as an imaging device configured by mounting a lens barrel 2 according to an embodiment to a camera body 3. In the following description, the subject side of the lens barrel 2 in the direction of the optical axis OA is referred to as the front side, and the camera body 3 side is referred to as the rear side. Movement of the lens barrel 2 in the direction of the optical axis OA is referred to as "linear movement," and rotation around the optical axis OA is referred to as "rotation." Furthermore, in the radial direction perpendicular to the optical axis OA of the lens barrel 2, the side away from the optical axis OA is referred to as the outer diameter side, and the side closer to the optical axis OA is referred to as the inner diameter side.

[0010] The camera 1 comprises a camera body 3 and a lens barrel 2. The lens barrel 2 has a lens mount LM at the rear (base end) thereof, which engages with a body mount BM of the camera body 3, thereby allowing the lens barrel 2 to be detachably attached to the camera body 3.

[0011] The camera body 3 is a so-called digital camera that has an image sensor 4 that converts optical images into electrical signals, and processes the image data captured by this image sensor 4 to record it in a recording unit (not shown) or display it on a display unit (not shown). The camera may be a single-lens reflex camera, a mirrorless camera, a compact digital camera, a twin-lens camera, or a camera built into a smartphone or tablet. A power switch (not shown) is provided on the camera body 3. An ON / OFF signal for the power switch and signals indicating focusing and aperture value are sent to a control unit 90 of the lens barrel 2, which will be described later.

[0012] The lens barrel 2 comprises, from the front, a first lens group L1, a second lens group L2, a third lens group L3, a fourth lens group L4, a fifth lens group L5, a sixth lens group L6, and a seventh lens group L7, and is a so-called zoom lens with an adjustable focal length.

[0013] The first lens group L1, the second lens group L2, the third lens group L3, the fourth lens group L4, the fifth lens group L5, the sixth lens group L6, and the seventh lens group L7 move in the direction of the optical axis OA during zooming. The fifth lens group L5 and the sixth lens group L6 are focus lens groups that move during focusing within the motor-driven barrel 100 (described later). The lens barrel 2 of this embodiment thus includes two focus lens groups. This allows for a reduction in the weight of each focus lens group, and they can be driven by an actuator with a small driving force, such as a stepping motor. This also improves focusing performance.

[0014] The first lens group L1 is held in a first frame 10, and a first sliding cylinder 12 extends rearward from the first frame 10. The second lens group L2 is held in a second frame 20. The third lens group L3 is held in a third frame 30. An aperture unit 32 is attached to the front side of the third frame 30. The fourth lens group L4 is held in a fourth frame 40, the fifth lens group L5 is held in a fifth frame 50, the sixth lens group L6 is held in a sixth frame 60, and the seventh lens group L7 is held in a seventh frame 70.

[0015] The lens barrel 2 includes an outer fixed barrel 84 and an inner fixed barrel 85, and a zoom ring 81 and a focus ring 86 are rotatably mounted on the outer periphery of the outer fixed barrel 84. Arranged in this order from the outer fixed barrel 84 toward the inner diameter side are the first group sliding barrel 12, the outer cam barrel 82, the inner fixed barrel 85, the inner cam barrel 83, and the motor moving barrel 100.

[0016] A connecting pin (not shown) extends radially inward from the zoom ring 81. The connecting pin passes through a circumferential groove (not shown) provided in the outer fixed barrel 84 and is connected to the outer cam barrel 82. When the zoom ring 81 is rotated in the circumferential direction, the connecting pin also rotates in the circumferential direction, and the outer cam barrel 82 rotates together with the zoom ring 81.

[0017] 2 is a perspective view of the inner cam barrel 83 of the lens barrel 2 and several barrel members arranged on its inner diameter side. Note that the fifth group lens L5 and the sixth group lens L6 are not shown. The inner cam barrel 83 has a cam follower 92 on its outer diameter side. The cam follower 92 passes through a cam groove (not shown) for cam drive provided in the inner fixed barrel 85 and is inserted into a linear groove (not shown) provided in the outer cam barrel 82. When the outer cam barrel 82 rotates in the circumferential direction, the cam follower 92 moves linearly while rotating in the circumferential direction, and the inner cam barrel 83 rotates and moves linearly. Additionally, the inner cam barrel 83 is provided with a cam groove 83a that drives the motor moving barrel 100. Note that the groove that is provided in the inner cam barrel 83 for driving the motor moving barrel 100 is not limited to a circumferential groove, and may be a circumferential groove or a rectilinear groove.

[0018] 3 is a perspective view of the inner cam barrel 83 removed from FIG. 2, seen from the subject side opposite to that of FIG. 2. A cam pin 101 extends radially outward from the motor moving barrel 100. The cam pin 101 engages with a cam groove 83a provided in the inner cam barrel 83 and a linear groove (not shown) in the inner fixed barrel 85. When the zoom ring 81 rotates, the inner cam barrel 83 moves straight while rotating, and the motor moving barrel 100 moves in a straight direction without rotating due to the linear component of the movement of the inner cam barrel 83 caused by the cam pin 101, and at the same time, the fifth group lens L5 and the sixth group lens L6 move straight.

[0019] A main guide bar 151 and a sub guide bar 152 for the fifth group, and a main guide bar 161 and a sub guide bar 162 for the sixth group extend between the front wall 103 of the motor moving barrel 100 and a guide bar pressing member 170 (shown in FIG. 1). The main guide bar 151, the sub guide bar 152, the main guide bar 161, and the sub guide bar 162 extend overlapping at approximately the same position in the direction of the optical axis OA. However, this is not a limitation, and it is sufficient that these guide bars at least partially overlap in the direction of the optical axis OA.

[0020] A fifth group driver 5M, which is, for example, a stepping motor, and a sixth group driver 6M, which is, for example, a stepping motor, are fixed to the motor moving barrel 100. Note that the fifth group driver 5M and the sixth group driver 6M are not limited to stepping motors, and may be motors such as voice coil motors or ultrasonic motors.

[0021] 4 is a diagram showing only the drive mechanism of the fifth group frame 50, with the motor moving barrel 100 removed from the state shown in FIG. 3. The drive mechanism of the sixth group frame 60 is substantially the same as the drive mechanism of the fifth group frame 50, so only the drive mechanism of the fifth group frame 50 will be described below, and a description of the drive mechanism of the sixth group frame 60 will be omitted.

[0022] Fifth group frame 50 is provided with fifth group holding portion 51 that covers the outer periphery of fifth group lens L5, and main guide bar engaging portion 511 and sub guide bar engaging portion 512 that extend radially outward from the outer periphery of fifth group holding portion 51. Sub guide bar engaging portion 512 is provided at a position approximately 180 degrees from main guide bar 151.

[0023] The main guide bar engagement portion 511 includes a front wall 511a and a rear wall 511b, and a side wall 511d connecting the front wall 511a and the rear wall 511b. The front wall 511a and the rear wall 511b are each provided with a guide bar insertion hole 511e through which a main guide bar 151 (described later) slidably passes.

[0024] A light-shielding portion 511c is provided to protrude radially outward from the side wall 511d. The light-shielding portion 511c is a rectangular plate-shaped portion extending a predetermined distance in the direction of the optical axis OA. The light-shielding portion 511c is a member for blocking light from a photointerrupter (PI) 5 attached to the motor-moving barrel 100. The position of the fifth lens group L5 can be detected by the light-shielding portion 511c and the PI5.

[0025] The sub-guide bar engagement portion 512 is a member provided with a U-shaped groove that is open on the outer diameter side. The sub-guide bar 152 is slidably inserted into this U-shaped groove. In this way, the U-shaped groove of the sub-guide bar engagement portion 512 engages with the sub-guide bar 152, preventing circumferential rotation around the main guide bar 151.

[0026] A unit frame 501, which is screwed to the motor moving barrel 100, is attached to the image side of the fifth group driver 5M in the direction of the optical axis OA. A lead screw 502 extends rearward in the direction of the optical axis OA from the fifth group driver 5M, and its rear end is rotatably held by the unit frame 501. Depending on the range of movement of the fifth group lens L5, the lead screw 502 may be configured to extend toward the subject side of the fifth group driver 5M in the direction of the optical axis OA. A moving rack 503 is engaged with the lead screw 502. The moving rack 503 is held by a main guide bar engagement portion 511.

[0027] 1, a main board 88 is attached with screws to the rear end of the internal fixed barrel 85. The main board 88 has a control unit 90, and when the focus ring 86 or zoom ring 81 rotates, the amount of rotation is detected and input to the control unit 90. Furthermore, a signal is also input from the camera body 3 to the control unit 90 when the photographer performs a focusing operation such as pressing the release button halfway. As a result, a pulse is sent from the control unit 90 to the fifth group driver 5M, which drives the fifth group driver 5M. Driven by the fifth group driver 5M, the lead screw 502 shown in FIG. 4 and other figures rotates, and the movable rack 503 that meshes with the lead screw 502 moves in the direction of the optical axis OA (the direction along the optical axis OA). As the movable rack 503 moves, the main guide bar engaging portion 511 is guided linearly by the main guide bar 151, and the fifth group frame 50 and the fifth group lens L5 move in the direction of the optical axis OA. Similarly, the sixth group frame 60 and the sixth group lens L6 are driven in the direction of the optical axis OA by the sixth group drive unit 6M during zooming and focusing. As described above, the fifth group lens L5 is moved in the optical axis direction by the motor moving barrel 100 and the fifth group driver 5M. Therefore, the amount of movement of the fifth group lens L5 is divided into the amount of movement by the motor moving barrel 100 and the amount of movement by the fifth group driver 5M. Similarly, the amount of movement of the sixth group lens L6 is divided into the amount of movement by the motor moving barrel 100 and the amount of movement by the sixth group driver 6M.

[0028] 5A and 5B are diagrams illustrating the movement states of the fifth lens group L5 and the sixth lens group L6, where (a) is at the wide-angle end W of the zoom position, and (b) is at the telephoto end T of the zoom position. In the embodiment, as described above, the lens barrel 2 includes the motor-movable barrel 100, which has the cam pin 101 and moves along the optical axis OA as the focal length is changed, the fifth-group drive unit 5M provided on the motor-movable barrel 100, the fifth-group lens L5 moved along the optical axis OA relative to the motor-movable barrel 100 by the fifth-group drive unit 5M, the sixth-group drive unit 6M provided on the motor-movable barrel 100, and the sixth-group lens L6 moved along the optical axis OA relative to the motor-movable barrel 100 by the sixth-group drive unit 6M. For simplicity, the fifth-group drive unit 5M, fifth-group frame 50, sixth-group drive unit 6M, sixth-group frame 60, sub-guide bar 152, sub-guide bar 162, etc. are omitted from Figures 5(a) and 5(b).

[0029] In the following description, as an example, the first focal length is the wide-angle end W and the second focal length is the telephoto end T. Furthermore, the fifth lens group L5 is positioned closest to the subject when the subject distance is the closest N at the first focal length (wide-angle end W) and the second focal length (telephoto end T), and is positioned closest to the image plane when the subject distance is infinity ∞. Furthermore, the sixth lens group L6 is positioned closest to the subject when the subject distance is the closest N at the first focal length (wide-angle end W) and the second focal length (telephoto end T), and is positioned closest to the image plane when the subject distance is infinity ∞.

[0030] (1) Relationship between the movement amounts X1 and X2 of the fifth lens group L5 As shown in Fig. 5(a), at the first focal length (wide-angle end W), the position of the fifth lens group L5 in the first state (WN) where the fifth lens group L5 is positioned closest to the subject is indicated by WN5 in Fig. 5(a). When the focal length is changed from the WN5 state shown in Fig. 5(a) to the second focal length (telephoto end T), the fifth lens group L5 moves to the TN5 position shown in Fig. 5(b). In this way, the amount of movement of the fifth lens group L5 relative to the motor-movable barrel 100 when the focal length is changed to the second focal length (telephoto end T) without changing the subject distance from the first state (WN) is denoted by X1. Furthermore, at the first focal length (wide-angle end W) shown in Figure 5(a), the position of the fifth lens group L5 in the second state (W∞) where the fifth lens group L5 is positioned closest to the image plane is indicated by W∞5 in Figure 5(a). When the focal length is changed from the W∞5 state shown in Figure 5(a) to the second focal length (telephoto end T), the fifth lens group L5 moves to the T∞5 position shown in Figure 5(b). In this way, the amount of movement of the fifth lens group L5 relative to the motor-movable barrel 100 when the focal length is changed to the second focal length (telephoto end T) from the second state (W∞) without changing the subject distance is designated as X2. At this time, the movement amount Z of the motor-moving cylinder 100 is set so that the movement amount X1 is smaller than the movement amount X2.

[0031] In other words, the drive amount X1 of the fifth group driver 5M when the focal length is changed from the first state of WN5 shown in FIG. 5(a) to the second focal length (telephoto end T) is smaller than the drive amount X2 of the fifth group driver 5M when the focal length is changed from the second state of W∞5 shown in FIG. 5(a) to the second focal length (telephoto end T).

[0032] Alternatively, the movement amount X1 of the fifth group lens L5 relative to the main guide bar 151 when the focal length is changed from the first state of WN5 shown in FIG. 5(a) to the second focal length (telephoto end T) is smaller than the movement amount X2 of the fifth group lens L5 relative to the main guide bar 151 when the focal length is changed from the second state of W∞5 shown in FIG. 5(a) to the second focal length (telephoto end T).

[0033] As a result, when the focal length is changed from a state in which the fifth lens group L5 is positioned closest to the subject, the movement amount X1 of the fifth lens group L5 relative to the motor-movable barrel 100 can be reduced, eliminating the need to extend the main guide bar 151 or the motor-movable barrel 100 toward the subject, thereby enabling the camera to be made thinner in the optical axis direction.

[0034] (2) Relationship between the movement amount X1 of the fifth lens group L5 and the movement amount Y1 of the sixth lens group L6 As shown in FIG. 5(a), the position of the sixth lens group L6 in the first state (WN) where the sixth lens group L6 is positioned closest to the subject at the first focal length (wide-angle end W) is indicated by WN6 in FIG. 5(a). When the focal length is changed from the WN6 state shown in FIG. 5(a) to the second focal length (telephoto end T), the sixth lens group L6 moves to the TN6 position shown in FIG. 5(b). In this manner, Y1 is the amount of movement of the sixth lens group L6 relative to the motor-movable barrel 100 when the focal length is changed to the second focal length (telephoto end T) without changing the subject distance from the first state (WN). Note that Y1 may be the amount of movement of the sixth lens group L6 relative to the main guide bar 161 when the focal length is changed from the first state (WN) to the second focal length (telephoto end T), or it may be the amount of drive of the sixth lens group driver 6M. At this time, the movement amount Z of the motor-moving cylinder 100 is set so that the movement amount X1 is smaller than the movement amount Y1. As a result, when the focal length is changed from a state in which the fifth lens group L5 is positioned closest to the subject, the amount of movement X1 of the fifth lens group L5 relative to the motor-movable barrel 100 can be reduced, eliminating the need to extend the main guide bar 151 or the motor-movable barrel 100 toward the subject, thereby enabling the camera to be made thinner in the optical axis direction.

[0035] Effects of (1) and (2) Within the motor-movable barrel 100, a fifth lens group L5 is arranged on the subject side, and a sixth lens group L6 is arranged on the image side. When the fifth group lens L5, which is arranged on the subject side of the motor-movable barrel 100, is arranged closest to the subject among the five lens groups, if the amount of movement of the motor-movable barrel 100 or the guide bar 151 due to zooming is increased, the lengths of the main guide bar 151 and the sub-guide bar 152 and the motor-movable barrel 100 must be increased, resulting in a larger size. According to the embodiment, when the fifth group lens L5, which is arranged on the subject side of the motor-movable barrel 100, is arranged closest to the subject, the amount of movement of the motor-movable barrel 100 and the guide bar 151 due to zooming is reduced, so there is no need to increase the length of the main guide bar 151 or the sub-guide bar 152, and the lens barrel 2 can be made smaller and thinner.

[0036] (3) Relationship between the movement amounts Y1 and Y2 of the sixth lens group L6 As shown in FIG. 5(a), at the first focal length (wide-angle end W), the position of the sixth lens group L6 in the second state (W∞) where the sixth lens group L6 is positioned closest to the image plane is indicated by W∞6 in FIG. 5(a). When the focal length is changed from the W∞6 state shown in FIG. 5(a) to the second focal length (telephoto end T), the sixth lens group L6 moves to the T∞6 position shown in FIG. 5(b). In this manner, Y2 is the amount of movement of the sixth lens group L6 relative to the motor-movable barrel 100 when the focal length is changed from the second state (W∞) to the second focal length (telephoto end T) without changing the subject distance. Note that Y2 may be the amount of movement of the sixth lens group L6 relative to the main guide bar 161 when the focal length is changed from the second state (W∞) to the second focal length (telephoto end T), or it may be the amount of drive of the sixth lens group driver 6M. In this case, the movement amount Z of the motor-movable barrel 100 is set so that Y2 is smaller than Y1. As a result, when the focal length is changed from the state in which the sixth lens group L6 is positioned closest to the image plane, the movement amount Y2 of the sixth lens group L6 relative to the motor-movable barrel 100 can be made small, so there is no need to extend the main guide bar 161 or the motor-movable barrel 100 toward the image plane. This allows the lens to be made thinner in the optical axis direction.

[0037] (4) Relationship between the movement amount X2 of the fifth lens group L5 and the movement amount Y2 of the sixth lens group L6 The movement amount Z of the motor movable barrel 100 is set so that the movement amount Y2 of the sixth lens group L6 relative to the motor movable barrel 100 when the focal length is changed from the second state (W∞) to the second focal length (telephoto end T) is smaller than the movement amount X2 of the fifth lens group L5 relative to the motor movable barrel 100 when the focal length is changed from the second state (W∞) to the second focal length (telephoto end T). As a result, when the focal length is changed from a state in which the sixth lens group L6 is positioned closest to the image plane, the movement amount Y2 of the sixth lens group L6 relative to the motor-movable barrel 100 can be reduced, eliminating the need to extend the main guide bar 161 or the motor-movable barrel 100 toward the image plane, thereby enabling the lens to be made thinner in the optical axis direction.

[0038] Effects of (3) and (4) Within the motor-movable barrel 100, a fifth lens group L5 is arranged on the subject side, and a sixth lens group L6 is arranged on the image side. When the sixth group of lenses L6, which is arranged on the image side of the motor-movable barrel 100, is arranged furthest to the image side among the six groups of lenses, if the amount of movement of the motor-movable barrel 100 or the guide bar 161 due to zooming is increased, the lengths of the main guide bar 161 and the sub-guide bar 162 and the motor-movable barrel 100 must be increased, resulting in a larger size. According to the embodiment, when the sixth group lens L6, which is arranged on the image side of the motor-movable barrel 100, is arranged furthest to the image side among the six group lenses, the amount of movement of the motor-movable barrel 100 and the guide bar 161 due to zooming is reduced, so there is no need to increase the length of the main guide bar 161 or the sub-guide bar 162, and the lens barrel 2 can be made smaller.

[0039] (5) Positional relationship between the 5th lens group L5 and the 6th lens group L6 The sixth lens group L6 (WN6) in the first state (at the wide-angle end W, the closest focus state N) is positioned closer to the image plane than the fifth lens group L5 (W∞5) in the second state (at the wide-angle end W, the infinity state ∞). Furthermore, the sixth lens group L6 (TN6) when the focal length is changed from the first state (WN) to the second focal length (telephoto end T) is positioned closer to the subject than the fifth lens group L5 (T∞5) when the focal length is changed from the second state (W∞) to the second focal length (telephoto end T). In other words, as shown in FIGS. 5(a) and 5(b), the positional relationship between the position (W∞5) where the fifth lens group L5 is positioned closest to the image plane at the wide-angle end W and the position (WN6) where the sixth lens group L6 is positioned closest to the subject is opposite to the positional relationship between the position (T∞5) where the fifth lens group L5 is positioned closest to the image plane at the telephoto end T and the position (TN6) where the sixth lens group L6 is positioned closest to the subject. This allows the fifth lens group L5 to move closer to the image plane and the sixth lens group L6 to move closer to the subject, allowing greater movement within the range of the guide bars 151 and 161 and the motor-movable barrel 100.

[0040] (5) Effect In a lens barrel 2 in which the fifth lens group L5 and the sixth lens group L6 move in the same direction from the closest point N state to the infinity point ∞ state, the positional relationship between the infinity point state (W∞5) of the fifth lens group L5 and the closest point state (WN6) of the sixth lens group L6 at the wide-angle end W changes from the positional relationship between the infinity point state (T∞5) of the fifth lens group L5 and the closest point state (TN6) of the sixth lens group L6 at the telephoto end T. This allows the guide bars 151, 152, 161, and 162 that guide the fifth lens group L5 and the sixth lens group L6 to be used efficiently, making it possible to make the lens barrel 2 smaller and thinner.

[0041] (6) Figure 6 is a diagram illustrating the movement amount of the fifth lens group L5 at the closest point N, the movement amount of the sixth lens group L6 at the infinity point ∞, and the movement amount of the motor-moving barrel 100 when the focal length is changed from the wide-angle end W to the telephoto end T. In the close-up N state, the amount of movement of the fifth lens group L5 when the focal length is changed from the wide-angle end W to the telephoto end T is defined as XX1. In the infinity ∞ state, the amount of movement of the sixth lens group L6 when the focal length is changed from the wide-angle end W to the telephoto end T is defined as YY1. Also, the amount of movement of the motor-movable barrel 100 when the focal length is changed from the wide-angle end W to the telephoto end T is defined as ZZ. In the embodiment, as shown in FIG. 6(a), the movement amount ZZ of the motor-movable barrel 100 when the movement amount XX1 of the fifth lens group L5 is larger than the movement amount YY1 of the sixth lens group L6 is larger than the movement amount ZZ of the motor-movable barrel 100 when the movement amount XX1 of the fifth lens group L5 is smaller than the movement amount YY1 of the sixth lens group L6, as shown in FIG. 6(b).

[0042] (6) Effect By setting the movement locus of the motor-moving cylinder 100 in this way, it is possible to make both X1 and Y2 in FIG. 5(b) small.

[0043] (7) The motor-movable barrel 100 moves in the direction of the optical axis OA when the lens barrel 2 zooms from the wide-angle end W to the telephoto end T. The fifth lens group L5 and the sixth lens group L6 are moved relative to the motor-movable barrel 100 by the fifth lens group drive unit 5M and the sixth lens group drive unit 6M. At this time, the fifth group lens L5 and the sixth group lens L6 move in one direction relative to the motor-movable barrel 100. That is, the positional relationship between the fifth group lens L5 and, for example, the cam pin 101 of the motor-movable barrel 100 always moves away from each other when zooming while focused on infinity ∞. Similarly, the positional relationship between the sixth group lens L6 and, for example, the cam pin 101 of the motor-movable barrel 100 always moves away from each other when zooming while focused on infinity ∞. However, this is not limiting, and the positional relationship between the fifth group lens L5 and the sixth group lens L6 and, for example, the cam pin 101 of the motor-movable barrel 100 may always be close or constant when zooming while focused on infinity ∞. At the closest distance N, the positional relationship between the fifth lens group L5 and the sixth lens group L6 and the motor-movable barrel 100 may always be closer, farther away, or constant when zooming while focused on infinity ∞.

[0044] (7) Effect If the positional relationship between the fifth group lens L5 and the sixth group lens L6 and the motor-movable barrel 100 is such that they move in the opposite direction (may make a U-turn) rather than in one direction when zooming while focused on infinity ∞, then the fifth group drive unit 5M and the sixth group drive unit 6M will rotate in the opposite direction. In this case, there is a possibility that a delay will occur due to backlash between the fifth group drive section 5M and the sixth group drive section 6M and the lead screw. However, in this embodiment, the fifth group drive section 5M and the sixth group drive section 6M always rotate in one direction, so no backlash occurs and no delay in movement or the like occurs. Since the lens barrel 2 is more likely to be zoomed at infinity than at close range, it is advisable to prevent reverse rotation at infinity as in the embodiment. However, reverse rotation may also be prevented at close range, or reverse rotation may be prevented at both infinity and close range.

[0045] In the above-described embodiment, the first focal length is the wide-angle end W and the second focal length is the telephoto end T, but this is not limiting. For example, the first focal length may be Middle 1, and the second focal length may be Middle 2, which is longer than Middle 1. In the above-described embodiment, the fifth lens group L5 is described as being positioned closest to the subject when the subject distance is the closest N at the wide-angle end W and the telephoto end T, and positioned closest to the image plane when the subject distance is the infinity ∞, but this is not limiting. For example, the fifth lens group L5 may be positioned closest to the subject when the subject distance is the infinity ∞, and positioned closest to the image plane when the subject distance is the closest N. Furthermore, the sixth lens group L6 has been described as being positioned closest to the subject when the subject distance is the closest N at the first focal length (wide-angle end W) and the second focal length (telephoto end T) and positioned closest to the image plane when the subject distance is the infinity ∞, but this is not limiting. For example, the sixth lens group L6 may be positioned closest to the subject when the subject distance is the infinity ∞ and positioned closest to the image plane when the subject distance is the closest N. The present invention is not limited to the above-described embodiments, and any combination may be used. [Explanation of symbols]

[0046] OA: Optical axis, 2: Lens barrel, 3: Camera body, 5M: 5th group drive unit, 50: 5th group frame, 51: 5th group holding unit, 6M: 6th group drive unit, 60: 6th group frame, 81: Zoom ring, 82: Outer cam barrel, 83: Inner cam barrel, 84: Outer fixed barrel, 85: Inner fixed barrel, 86: Focus ring, 90: Control unit, 92: Cam follower, 100: Motor moving barrel, 101: Cam pin, 103: Front wall, 151: Main In-guide bar, 152: sub-guide bar, 161: main guide bar, 162: sub-guide bar, 170: guide bar holding member, 501: unit frame, 502: lead screw, 503: moving rack, 511: main guide bar engagement part, 511a: front wall, 511b: rear wall, 511c: light shielding part, 511d: side wall, 511e: guide bar insertion hole, 512: sub-guide bar engagement part

Claims

1. an optical system having, in order from the object side, a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group; a moving cylinder that moves along the optical axis by changing the focal length; a first drive unit provided on the movable barrel; a second drive unit provided on the movable barrel, the fifth lens group is moved relative to the movable barrel along the optical axis by the first drive unit during focusing; the sixth lens group is moved relative to the movable barrel along the optical axis by the second drive unit during focusing; A lens barrel in which the amount of movement of the fifth lens group relative to the movable barrel when the focal length is changed to the telephoto end in a first state in which the fifth lens group is positioned closest to the subject at the wide-angle end is smaller than the amount of movement of the fifth lens group relative to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end in a second state in which the fifth lens group is positioned closer to the image plane at the wide-angle end than in the first state.

2. The amount of movement of the sixth lens group relative to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end in the second state is smaller than the amount of movement of the sixth lens group relative to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end in the first state. The lens barrel according to claim 1 .

3. The amount of movement of the sixth lens group relative to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end in the second state is smaller than the amount of movement of the fifth lens group relative to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end in the second state.

3. The lens barrel according to claim 1.

4. The sixth lens group in the second state is disposed closer to the image plane than the sixth lens group in the first state. The lens barrel according to any one of claims 1 to 3.

5. The movable barrel has a cam follower, When the focal length is changed in the first state or the second state, the sixth lens group moves in a certain direction relative to the cam follower. The lens barrel according to any one of claims 1 to 4.

6. The fifth lens group in the first state moves toward the image plane when the focal length is changed from the wide-angle end to the telephoto end. The lens barrel according to any one of claims 1 to 5.

7. 7. The lens barrel according to claim 1, wherein the sixth lens group in the first state moves toward an image plane when the focal length is changed from a wide-angle end to a telephoto end.

8. the movement amount of the movable barrel when the movement amount of the fifth lens group when the focal length is changed from the wide-angle end to the telephoto end in the first state is larger than the movement amount of the sixth lens group when the focal length is changed from the wide-angle end to the telephoto end in the second state, The amount of movement of the fifth lens group when the focal length is changed from the wide-angle end to the telephoto end in the first state is smaller than the amount of movement of the sixth lens group when the focal length is changed from the wide-angle end to the telephoto end in the second state, and is larger than the amount of movement of the movable barrel when The lens barrel according to any one of claims 1 to 7.

9. an optical system having, in order from the object side, a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group; a moving cylinder that moves along the optical axis by changing the focal length; a first drive unit provided on the movable barrel; a second drive unit provided on the movable barrel, the fifth lens group is moved relative to the movable barrel along the optical axis by the first drive unit during focusing; the sixth lens group is moved relative to the movable barrel along the optical axis by the second drive unit during focusing; A lens barrel in which, in a first state in which the fifth lens group is positioned closest to the subject at the wide-angle end, the amount of movement of the fifth lens group relative to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end is smaller than the amount of movement of the sixth lens group relative to the movable barrel when the focal length is changed from the wide-angle end to the telephoto end in the first state.

10. an optical system having, in order from the object side, a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group; a moving cylinder that moves along the optical axis by changing the focal length; a first drive unit provided on the movable barrel; a second drive unit provided on the movable barrel, the fifth lens group is moved by the first drive unit along the optical axis relative to the movable barrel toward the image plane during focusing; the sixth lens group is moved by the second drive unit along the optical axis relative to the movable barrel toward the image plane during focusing; A lens barrel in which the amount of movement of the fifth lens group, which is arranged closest to the subject, when the focal length is changed is smaller than the amount of movement of the sixth lens group, which is arranged closest to the subject, when the focal length is changed.

11. An imaging device comprising the lens barrel according to any one of claims 1 to 10.

Images