Lens barrel holder

Abstract

It provides a lightweight lens barrel equipped with two focusing lenses. [Solution] The lens barrel 2 includes a first lens holding frame 50 that holds a first lens L5 and has a projection that protrudes in a direction intersecting the optical axis, a first drive unit that moves the first lens holding frame in the optical axis direction, a first guide bar that engages with the projection and guides the first lens holding frame in the optical axis direction, a second lens holding frame 60 that holds a second lens L6 arranged alongside the first lens L5 along the optical axis and has a first hood portion 62 that extends from a part of the outer circumference of the second lens L6 toward the first lens holding frame, and a second drive unit that moves the second lens holding frame in the optical axis direction. When the first lens holding frame and the second lens holding frame approach each other, at least a part of the projection is located in the region that extends from a part of the outer circumference of the second lens toward the first lens holding frame, in a region where the first hood portion is not provided in the circumferential direction centered on the optical axis.

Description

Technical Field

[0001] The present invention relates to a lens barrel.

Background Art

[0002] Conventionally, various proposals have been made for a lens barrel provided with a focus lens and adopting a stepping motor as a drive mechanism for the focus lens (see, for example, Patent Document 1). However, since the stepping motor in Patent Document 1 has a small driving force, it cannot move a heavy focus lens in the optical axis direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] A lens barrel according to an aspect of the present invention includes a first lens holding frame that holds a first lens and has a protrusion protruding in a direction intersecting the optical axis, a first driving unit that moves the first lens holding frame in the optical axis direction, a first guide bar that engages with the protrusion and guides the first lens holding frame in the optical axis direction, a second lens holding frame that holds a second lens arranged along the optical axis and aligned with the first lens, and has a first hood portion extending from a part of the outer periphery of the second lens toward the first lens holding frame, and a second driving unit that moves the second lens holding frame in the optical axis direction. When the first lens holding frame and the second lens holding frame approach each other, at least a part of the protrusion is located in a region extending from a part of the outer periphery of the second lens toward the first lens holding frame and where the first hood portion is not provided in the circumferential direction centered on the optical axis.

Brief Description of the Drawings

[0005] [Figure 1]This is a conceptual diagram of a camera 1, which is configured by attaching a lens barrel, an embodiment of the present invention, to a camera body. [Figure 2] This is a partial cross-sectional view of the lens barrel. [Figure 3] This is a view of a portion of the focus ring from the inner diameter side. [Figure 4] This is a view of a portion of the outer fixing cylinder from the outer diameter side. [Figure 5] This is a side view of the motor sliding cylinder and the portion of the motor sliding cylinder located on the inner diameter side. [Figure 6] This is a perspective view showing the 5-group lens drive unit. [Figure 7] Figure 6 is a perspective view showing the mobile rack section. [Figure 8] This is a radial cross-sectional view of the inner fixing cylinder, motor sliding cylinder, 5-group cylinder, 6-group cylinder, and STM5 and STM6 viewed from the rear. [Figure 9] This diagram illustrates the position of the main guide bar in the optical axis direction OA. [Figure 10] This diagram illustrates the engagement length between the main guide bar engagement portion of the 5-group barrel and the main guide bar, and the engagement length between the main guide bar engagement portion of the 6-group barrel and the main guide bar. [Figure 11] This diagram shows the positional relationship between the 5-group and 6-group frames when the focal length is at the telephoto end and the subject distance is at infinity. [Figure 12] This diagram shows the positional relationship between the 5-group frame 50 and the 6-group frame when the focal length is at the wide-angle end and the subject distance is at the close-up end. [Figure 13] This figure shows the positional relationship between the 5-group frame and the 6-group frame in a wide-angle view, similar to Figure 12, but from a different angle, indicating that the 5-group holding portion of the 5-group frame and the 6-group hood portion of the 6-group frame are close together. [Figure 14] This is a cross-sectional view of a part of the lens barrel, showing the 4th and 5th lens groups close together. [Figure 15] This is a magnified view of the 4-group lens and the 5-group hood section, showing the state where the 5-group hood section does not cover the 4-group frame holder section. [Figure 16]This is a flowchart illustrating the initial operation of the lens barrel control unit. [Figure 17] This diagram illustrates the position of the 5-group photointerrupter on the optical axis and the position of the 6-group photointerrupter. [Modes for carrying out the invention]

[0006] Figure 1 is a conceptual diagram of a camera 1, which is configured by attaching a lens barrel 2, one embodiment of the present invention, to a camera body 3. In the following description, the side of the lens barrel 2 facing the subject in the direction of the optical axis OA is referred to as the front, and the side facing the camera body 3 is referred to as the rear. 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 moving away from the optical axis OA is referred to as the outer diameter side, and the side moving closer to the optical axis OA is referred to as the inner diameter side.

[0007] Camera 1 comprises a camera body 3 and a lens barrel 2. The lens barrel 2 is provided with a lens mount LM at its rear (base) end and is detachably attached to the camera body 3 by engaging with the body mount BM of the camera body 3.

[0008] The camera body 3 is a so-called digital single-lens reflex (SLR) camera equipped with an image sensor 4 that converts light images into electrical signals, and processes the image data from this image sensor 4 and records it in a recording unit (not shown). However, it is not limited to digital SLR cameras. A mirrorless camera or a compact digital camera may also be used. Furthermore, a twin-lens reflex camera may also be used. Even a camera built into a smartphone or tablet may be used. The camera body 3 is equipped with a power switch (not shown). The ON / OFF signal from the power switch, as well as signals indicating focusing and aperture values, are sent to the control unit 90 of the lens barrel 2, which will be described later.

[0009] (1. Overview of Lens Tube 2) The lens barrel 2 includes, from the front side, a first-group lens L1, a second-group lens L2, a third-group lens L3, a fourth-group lens L4, a fifth-group lens L5, a sixth-group lens L6, and a seventh-group lens L7, and is a so-called zoom lens with a variable focal length. Note that it is not limited to a zoom lens, and it may be a single-focus lens with an unchangeable focal length.

[0010] (1-1. Each group of lenses L1~L7) The first-group lens L1, the second-group lens L2, the third-group lens L3, the fourth-group lens L4, the fifth-group lens L5, the sixth-group lens L6, and the seventh-group lens L7 move during zooming. Also, the fifth-group lens L5 and the sixth-group lens L6 are focus lens groups that move during focusing. The lens barrel 2 of the present embodiment includes two focus lens groups. Therefore, the weight per focus lens group can be reduced, and it can be driven even by an actuator with a small driving force such as a stepping motor. Also, the focusing performance can be improved. The first-group lens L1 is held by the first-group frame 11, and a first-group sliding cylinder 12 extends rearward from the first-group frame 11. The second-group lens L2 is held by the second-group frame 21. The third-group lens L3 is held by the third-group frame 31. The fourth-group lens L4 is held by the fourth-group frame 41. The fourth-group frame 41 includes a fourth-group holding portion 43 that holds the outer periphery of the fourth-group lens L4, a front wall portion 44 that extends from the fourth-group holding portion 43 to the outer diameter side, and a cylindrical portion 45 that extends rearward from the outer diameter side end portion of the front wall portion 44. A diaphragm unit 42 is attached to the front side of the fourth-group frame 41.

[0011] The fifth-group lens L5 is held by the fifth-group frame 50. The fifth-group frame 50 includes a fifth-group holding portion 51 that covers the outer periphery of the fifth-group lens L5, and a fifth-group hood portion 52 that extends forward from the fifth-group holding portion 51. The fifth-group hood portion 52 may extend rearward. The fifth-group hood portion 52 is provided to prevent ghosts due to the incidence of unnecessary light, etc. Note that instead of the fifth-group hood portion 52, a cylindrical portion 52 may be used. The 6-group lens L6 is held in the 6-group frame 60. The 6-group frame 60 includes a 6-group holding portion 61 that covers the outer periphery of the 6-group lens L6, and a 6-group hood portion 62 that extends forward from the 6-group holding portion 61. The 6-group hood portion 62 may extend rearward. The 6-group hood portion 62 is provided to prevent ghosts caused by the incidence of unnecessary light or the like. Note that, instead of the 6-group hood portion 62, a cylindrical portion 62 may be used. The 5-group frame 50 and the 6-group frame 60 are disposed on the inner diameter side of the motor sliding cylinder 100. The motor sliding cylinder 100 is disposed within the cylindrical portion 45 of the 4-group frame 41. The motor sliding cylinder 100 is driven in the direction of the optical axis OA during zooming. Also, during zooming and focusing, the 5-group frame 50 is driven in the direction of the optical axis OA by a 5-group motor (for example, a stepping motor, hereinafter referred to as STM5) fixed to the motor sliding cylinder 100, and the 6-group frame 60 is driven in the direction of the optical axis OA by a 6-group motor (hereinafter referred to as STM6). Note that the motor is not limited to a stepping motor, and a DC motor, a voice coil motor, an ultrasonic motor, or the like may also be used.

[0012] The 7-group lens L7 is held in the 7-group frame 70. The 7-group frame 70 includes a 7-group holding portion 71 that covers the outer periphery of the 7-group lens L7, and a 7-group hood portion 72 that extends forward from the 7-group holding portion 71. The 7-group hood portion 72 may extend rearward. A 7-group sliding cylinder 73 is attached to the front end of the 7-group frame 70. The 7-group hood portion 72 is provided to prevent ghosts caused by the incidence of unnecessary light or the like. Note that, instead of the 7-group hood portion 72, a cylindrical portion 72 may be used. The 1-group lens L1, 2-group lens L2, 3-group lens L3, 4-group lens L4, 5-group lens L5, 6-group lens L6, and 7-group lens L7 are driven in the direction of the optical axis OA by the rotation of an outer cam cylinder 82 and an inner cam cylinder 83 that rotate by the rotation of a zoom ring 81 described later.

[0013] (1-2. Mechanical Structure) The lens barrel 2 comprises an outer fixed barrel 84 and an inner fixed barrel 85. A zoom ring 81 and a focus ring 86 are rotatably mounted on the outer circumference of the outer fixed barrel 84. An aperture ring may also be provided.

[0014] Between the outer fixed cylinder 84 and the inner fixed cylinder 85, a group of sliding cylinders 12 and an outer cam cylinder 82 are arranged from the outer diameter side. On the inner diameter side of the inner fixing cylinder 85, the second group frame 21, the third group frame 31, the fourth group frame 41, the motor sliding cylinder 100, and the seventh group frame 70 are arranged. On the inner diameter side of the motor sliding cylinder 100, the fifth group frame 50 and the sixth group frame 60 are arranged. Furthermore, the motor sliding cylinder 100 is located on the inner diameter side of the fourth group frame 41. The rear side of the cylindrical portion 45 of the 4-group frame 41 has a smaller diameter than the front side, and the inner cam cylinder 83 is positioned between this smaller diameter portion and the inner fixing cylinder 85.

[0015] (1-2-1. Outer cam cylinder 82, inner cam cylinder 83, outer fixing cylinder 84, inner fixing cylinder 85) A first connecting pin 91 extends from the zoom ring 81 towards the inner diameter side. The first connecting pin 91 passes through a circumferential groove provided in the outer fixing cylinder 84 and is connected to the outer cam cylinder 82. When the zoom ring 81 is rotated in the circumferential direction, the first connecting pin 91 also rotates in the circumferential direction, and the outer cam cylinder 82 rotates together with the zoom ring 81. A second connecting pin 92 extends from the inner cam cylinder 83 toward the outer diameter. The second connecting pin 92 passes through a cam groove for cam driving provided in the inner fixed cylinder 85 and is inserted into a straight groove provided in the outer cam cylinder 82. When the outer cam cylinder 82 rotates in the circumferential direction, the second connecting pin 92 also rotates in the circumferential direction, causing the inner cam cylinder 83 to rotate and move in a straight line. The outer cam cylinder 82 is provided with four types of cam grooves, which drive the first group sliding cylinder 12, the second group frame 21, the third group frame 31, and the fourth group frame 41, respectively. The inner cam cylinder 83 is provided with a cam groove for driving the 7-group sliding cylinder 73 and a circumferential groove for driving the motor sliding cylinder 100. In other words, the amount of movement of the inner cam cylinder 83 and the amount of movement of the motor sliding cylinder 100 are the same. Alternatively, a cam groove for driving the motor sliding cylinder 100 may be provided to make the amount of movement of the inner cam cylinder 83 and the amount of movement of the motor sliding cylinder 100 different. The outer fixing cylinder 84 is provided with a straight groove that guides the group of sliding cylinders 12 in a straight line. The inner fixing cylinder 85 is provided with three types of straight grooves that guide the second group frame 21, the third group frame 31, and the fourth group frame 41 in a straight line, respectively. It is also provided with a cam groove that drives the seventh group sliding cylinder 73. Furthermore, as described above, it is provided with a cam groove for the inner cam cylinder 83. The 4-group frame 41 is provided with a straight groove that guides the motor sliding cylinder 100 in a straight line.

[0016] (1-2-2. Mechanical drive of each lens group) The first group of sliding cylinders 12 moves in a straight line in the optical axis OA direction without rotating, due to the cam groove of the outer cam cylinder 82 and the straight groove of the outer fixed cylinder 84. The second group frame 21, the third group frame 31, and the fourth group frame 41 move linearly in the optical axis OA direction without rotating, due to the cam groove of the outer cam cylinder 82 and the linear groove of the inner fixing cylinder 85. In other words, they are driven in the optical axis OA direction by the cam groove of the rotating outer cam cylinder 82, while being linearly guided by the linear groove of the inner fixing cylinder 85. The motor sliding cylinder 100 moves in a straight line in the optical axis direction OA without rotating, due to the circumferential groove of the inner cam cylinder 83 and the straight groove of the 4-group frame 41.

[0017] The seven sliding cylinders 73 move linearly in the optical axis direction OA without rotating, due to the cam groove of the rotating and linearly moving inner cam cylinder 83 and the cam groove of the inner fixed cylinder 85.

[0018] (1-3. Configuration of the focusing mechanism) (1-3-1. Mechanical drive of motor sliding cylinder 100) Figure 2 is a partial cross-sectional view of the lens barrel 2. Note that the position and angle of each lens group differ from those in Figure 1. As shown in the figure, the motor sliding cylinder 100 is positioned on the inner diameter side of the 4-group frame 41 (tube section 45). As described above, when the zoom ring 81 rotates, the outer cam cylinder 82 also rotates due to the first connecting pin 91. The outer cam cylinder 82 and the inner cam cylinder 83 are engaged by the second connecting pin 92, which passes through the cam groove of the inner fixed cylinder 85, so when the outer cam cylinder 82 rotates, the inner cam cylinder 83 rotates and moves in a straight line. A cam pin 101 extends outward from the motor sliding cylinder 100. The cam pin 101 passes through a straight groove 45a provided in the cylindrical portion 45 of the 4-group frame 41 and engages with a circumferential groove 83a provided in the inner cam cylinder 83. Therefore, as the inner cam cylinder 83 rotates and moves in a straight line, the motor sliding cylinder 100 is guided in a straight line by the cam pin 101 and the straight groove 45a provided in the cylinder portion 45, and moves in the straight line direction along with the straight line component of the movement of the inner cam cylinder 83. Thus, when the zoom ring 81 rotates, the motor sliding cylinder 100 moves in a straight line without rotating, so the 5-group lens L5 and the 6-group lens L6 move in a straight line. Furthermore, STM5 and STM6 are fixed to the motor sliding cylinder 100. Based on the rotation of the zoom ring 81 or the focus ring 86, STM5 drives the 5-group lens L5 in the optical axis direction, and STM6 drives the 6-group lens L6 in the optical axis direction. In other words, the 5-group lens L5 (5-group frame 50) and the 6-group lens L6 (6-group frame 60) move in the optical axis direction relative to the motor sliding cylinder 100. Lens driving by STM5 and STM6 will be described later.

[0019] Figure 5 is a side view including the motor sliding cylinder 100 and the portion on the inner diameter side of the motor sliding cylinder 100. The motor sliding cylinder 100 is fixed with screws to a 5-group lens drive unit 500 that drives the 5-group lens L5 and a 6-group lens drive unit 600 that drives the 6-group lens L6 (screws are not shown in the figure). Figure 6 is a perspective view showing the 5-group lens drive unit 500.

[0020] The motor sliding cylinder 100 is fitted with a 5-group lens drive unit 500, which includes an STM5 that drives a 5-group lens L5 that is a focusing lens, and a 6-group lens drive unit 600, which includes an STM6 that drives a 6-group lens L6 that is a focusing lens.

[0021] (1-3-2. Drive control of L5 and L6 by the lens drive unit) Figure 3 shows a view of a portion of the focus ring 86 from the inner diameter side. Figure 4 shows a view of a portion of the outer fixing cylinder 84 from the outer diameter side. As shown in Figure 3, a reflective tape 86a is attached to the inner diameter side of the focus ring 86 in the circumferential direction. A light-shielding line 86b is formed on the reflective tape 86a, extending in the direction of the optical axis OA. As shown in Figure 4, a photointerrupter 84a for detecting the rotation of the focus ring 86 is attached to the outer diameter side of the outer fixing cylinder 84 located on the inner circumference side of the focus ring 86. When the focus ring 86 is rotated, the reflective tape 86a also rotates. The photointerrupter 84a detects the light-shielding pulses generated by the light-shielding line 86b of the reflective tape 86a. The number of these light-shielding pulses corresponds to the amount of rotation of the focus ring 86.

[0022] As shown in Figure 1, the main circuit board 88 is attached to the rear end of the internal fixing cylinder 85 by screws. An FPC (not shown in the figure) extends from the photo interrupter 84a to the main circuit board 88. The main circuit board 88 has a control unit 90, and a light-shielding pulse signal corresponding to the amount of rotation of the focus ring 86 is input from the photo interrupter 84a to the control unit 90 via the FPC. With this configuration, the amount of rotation of the focus ring 86 can be detected.

[0023] When the focus ring 86 rotates, the photo interrupter 84a detects the amount of rotation and sends a signal to the control unit 90 on the main board 88. In addition, focusing operations such as the photographer half-pressing the shutter release also send a signal from the camera body 3 to the control unit 90 on the main board 88. When this happens, a pulse is sent from the control unit 90 to the STM5, and the STM5 is driven. When the STM5 is driven, the lead screw 502 rotates, allowing the 5-group lens L5 to move. The same procedure is followed for driving the 6-group lens L6.

[0024] Furthermore, the inner diameter side of the zoom ring 81 is provided with a rotation detection unit (not shown) that detects the amount of rotation of the zoom ring 81. For example, a potentiometer can be used. An FPC extends from the potentiometer to the main board 88. The control unit 90 can determine the amount of rotation of the zoom ring 81 based on the value detected from the potentiometer. When the potentiometer detects the rotation of the zoom ring 81, the control unit 90 drives the STM5 with a drive amount corresponding to the amount of rotation of the zoom ring 81. When the STM5 is driven, the 5-group lens L5 moves in the direction of the optical axis OA. The same applies to the 6-group lens L6. Furthermore, a potentiometer may be used to detect the rotation of the focus ring, and reflective tape and a photointerrupter may be used to detect the rotation of the zoom ring. Other detection means, such as magnetic detection, may also be used.

[0025] (1-3-3. Details of the lens drive unit) Next, we will explain the 5-group lens drive unit 500. The 6-group lens drive unit 600 has the same configuration as the 5-group lens drive unit 500, so we will omit its explanation.

[0026] As shown in Figure 6, the 5-group lens drive unit 500 comprises a unit frame 501 screwed to the motor sliding cylinder 100, an STM 5 fixed to the front end of the unit frame 501, a lead screw 502 extending from the STM 5 to the rear in the direction of the optical axis OA, with its rear end rotatably held by the unit frame 501, and a movable rack 503 that meshes with the lead screw 502 and moves in the direction of the optical axis OA as the lead screw 502 rotates. Note that the STM 5 may be fixed to the rear end of the unit frame 501. In that case, the lead screw 502 extends from the STM 5 to the front in the direction of the optical axis OA. Note that the lead screw 602 extending from the STM 6 may extend in the same direction as the lead screw 502, or in the opposite direction. That is, if the lead screw 502 extends to the rear in the direction of the optical axis OA, the lead screw 602 will also extend to the rear in the direction of the optical axis OA. In this case, the relationship between the drive direction of STM5 and the movement direction of the 5-group lens L5 can be the same as the relationship between the drive direction of STM6 and the movement direction of the 6-group lens L6. Alternatively, if the lead screw 502 extends to the rear in the direction of the optical axis OA, the lead screw 602 may extend to the front in the direction of the optical axis OA. In this case, the lens barrel can be made thinner in the direction of the optical axis.

[0027] (Unit slot 501) The unit frame 501 includes a plate-shaped unit fixing portion 501a extending in the direction of the optical axis OA, an STM fixing portion 501b extending from the unit fixing portion 501a at approximately a right angle in the inward direction at the front end of the unit fixing portion 501a, and a lead screw holding portion 501c extending from the unit fixing portion 501a at approximately a right angle in the inward direction at the rear end of the unit fixing portion 501a.

[0028] As shown in Figure 5 above, the unit fixing portion 501a is positioned on the outer circumference of the motor sliding cylinder 100 and is screwed to the motor sliding cylinder 100. The STM 5 is fixed to the STM fixing part 501b, and the rear end of the lead screw 502 is rotatably held in the lead screw holding part 501c.

[0029] (STM5) The STM5 is connected to an FPC (not shown) extending from the main board 88.

[0030] (Lead screw 502) The lead screw 502 is rotationally driven by the rotational force of the STM5. The outer circumference of the lead screw 502 is threaded.

[0031] (Mobile rack 503) Figure 7 is a perspective view showing only the portion of the movable rack 503 in Figure 6. The movable rack 503 comprises a meshing portion 504 and an engaging shaft portion 505. The meshing portion 504 has a U-shaped radial cross-section, and the meshing portion 504 that meshes with the threaded portion of the lead screw 502 is provided on the inner surface of the U-shaped portion through which the lead screw 502 is inserted. An engagement shaft portion 505 is provided on the opposite side in the circumferential direction of the lens barrel 2 from the portion of the movable rack 503 where the meshing portion 504 is provided. The engaging shaft portion 505 is a cylindrical member extending in the direction of the optical axis OA, and in this embodiment, it has portions with different diameters in the following order from the rear: rear small diameter portion 505a, medium diameter portion 505b, large diameter portion 505c, and front small diameter portion 505d.

[0032] (1-3-4. Details of the lens group frame) As shown in Figure 6, the 5-group frame 50 is provided with a projection 510 that extends radially outward from the outer circumference of the portion covering the outer circumference of the 5-group lens L5. The projection 510 comprises a main guide bar engaging portion 511, a light-shielding portion 512 (light-shielding portion 612 in the case of a 6-group frame), and a rack engaging portion (linear drive portion) 513. The protrusion 510 is for driving the 5-group lens L5, which corresponds to the 5-group lens drive unit 500. A similar protrusion 610 (shown in Figure 8 below) is also provided for driving the 6-group lens L6, but since its configuration is the same as the protrusion 510 for driving the 5-group lens L5, the explanation will be omitted.

[0033] (Main guide bar engagement portion 511) The main guide bar engaging portion 511 comprises a front wall 511a, a rear wall 511b provided parallel to and spaced apart from the front wall 511a, and two side walls 511c and 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 the main guide bar 151, described later, slides.

[0034] Figure 8 is a radial cross-sectional view of the inner fixing cylinder 85, motor sliding cylinder 100, 5-group holding section 51, 6-group holding section 61, and STM5 and STM6 as seen from the front. As described above with reference to Figure 6, a projection 510 is provided extending outward from the outer circumference of the 5-group holder 51. The projection 510 includes a main guide bar engaging portion 511. The 5-group holder 51 is also provided with a sub-guide bar engaging portion 552 extending radially from the outer circumference. The sub-guide bar engaging portion 552 is positioned approximately 180 degrees relative to the main guide bar 151 of the projection 510.

[0035] As described above, the main guide bar engaging portion 511 comprises a front wall 511a and a rear wall 511b that are parallel to each other and spaced apart, and the main guide bar 151 is inserted through the guide bar insertion holes 511e provided in each (in the following description, the distance from the front end of the front wall 511a to the rear end of the rear wall 511b will be called the engaging length). The 5-group holding portion 51 is guided in the direction of the optical axis OA by this main guide bar 151.

[0036] The sub-guide bar engaging portion 552 is a member provided with a U-shaped groove that is open on the outer diameter side. The sub-guide bar 152 is inserted through this U-shaped groove. In this way, the U-shaped groove of the sub-guide bar engaging portion 552 engages with the sub-guide bar 152, preventing circumferential rotation around the main guide bar 151. Similarly, for the 6-group frame 60, the sub-guide bar engaging portion 652 extends outward at a position approximately 180 degrees from the protruding portion 610 on which the main guide bar engaging portion 611 is provided in the lens holding portion.

[0037] (Light-shielding part 512) The light-shielding portion 512 is provided projecting outward from the side wall 511d. The light-shielding portion 512 is a rectangular plate-shaped portion extending a predetermined distance in the direction of the optical axis OA. The light-shielding portion 512 may also be provided on the side wall 511c. The light-shielding portion 512 is a member for shielding the PI5 provided on the motor sliding cylinder from light. The position of the 5-group lens L5 can be detected by the light-shielding portion 512 and PI5.

[0038] (Rack engagement portion 513) The rack engagement portion 513 extends from the side wall 511c toward the 5-group lens drive unit 500. The rack engagement portion 513 comprises a front arm 513a and a rear arm 513b provided in a parallel and spaced relationship with respect to the front arm 513a. The rear arm 513b extends continuously from the rear wall 511b toward the five-group lens drive unit 500, while the front arm 513a extends toward the five-group lens drive unit 500 from the other side wall 511c, at a position closer to the rear wall 511b than to the front wall 511a. The front arm 513a and the rear arm 513b are provided with through holes 513d and 513e, respectively. The through hole 513d in the front arm 513a is a circular through hole. The through hole 513e in the rear arm 513b is a circular through hole, but it has a notch in the radial direction.

[0039] An engagement shaft portion 505 is positioned between the front arm 513a and the rear arm 513b. The through holes 513d and 513e are larger in diameter than the two rear small-diameter portions 505a and front small-diameter portion 505d of the engaging shaft portion 505. Also, the through holes 513d and 513e are smaller in diameter than the medium-diameter portion 505b and large-diameter portion 505c of the engaging shaft portion 505. The front small-diameter portion 505d of the engaging shaft portion 505 is inserted into the through hole 513d of the front arm 513a. The rear small-diameter portion 505a of the engaging shaft portion 505 is inserted into the through hole 513e of the rear arm 513b. At this time, since the through hole 513e is provided with a notch, after inserting the front small-diameter portion 505d into the through hole 513d of the front arm 513a, the rear small-diameter portion 505a can be inserted laterally into the through hole 513e from the notch.

[0040] (Coil spring 506) Due to manufacturing errors or deflection of the front arm 513a and rear arm 513b, when the medium-diameter portion 505b and large-diameter portion 505c of the engaging shaft portion 505 are positioned between the front arm 513a and the rear arm 513b, a gap may be created between the side surface of the small-diameter portion 505a of the medium-diameter portion 505b and the side surface of the large-diameter portion 505c on the medium-diameter portion 505b side, and the sides of the front arm 513a and rear arm 513b, causing the engaging shaft portion 505 to wobble relative to the rack engaging portion 513. Therefore, a coil spring 506 is positioned on the outer circumference of the medium-diameter portion 505b. The diameter of the coil spring 506 is larger than the diameters of the small-diameter portion 505a and the medium-diameter portion 505b, and smaller than the diameter of the large-diameter portion 505c. The coil spring 506 is positioned between the rear arm 513b and the large-diameter portion 505c, biasing the rear arm 513b (i.e., the 5-group frame 50) towards the rear in the direction of the optical axis OA.

[0041] When the lead screw 502 rotates due to the drive of the STM5, the movable rack 503 moves in the direction of the optical axis OA (the direction along the optical axis OA) due to the engagement of the meshing portion 504 of the movable rack 503 with the threaded portion of the lead screw 502. Furthermore, since the coil spring 506 also generates a biasing force in the circumferential direction, the 5-group frame 50 can also be biased in the circumferential direction.

[0042] Figure 9 illustrates the positions of the main guide bars 151, 161 and sub-guide bars 152, 162 extending along the optical axis OA. As shown in the figure, a guide bar retaining member 170 is screwed to the rear end of the 4-group frame 41. The guide bar retaining member 170 may be integrally formed with the 4-group frame 41 instead of being screwed in. In that case, the guide bar retaining member 170 can be considered as part of the 4-group frame 41. The main guide bar 151 and sub-guide bar 152 for the 5th group, and the main guide bar 161 and sub-guide bar 162 for the 6th group, extend between the front wall portion 44 of the 4th group frame 41 and the guide bar retaining member 170. The sub-guide bar may be shared between the 5-group and 6-group systems. In this case, one guide bar can be eliminated. The main guide bar may also be shared between the 5-group and 6-group systems.

[0043] (2. Location of the lens drive unit) Returning to Figure 8, when viewed from one side of the optical axis OA (the front in Figure 8), the main guide bar 151 is positioned closer to the STM5 (or the lead screw 502 extending from the STM5) than the sub-guide bar 152. In other words, the STM5 (or the lead screw 502 extending from the STM5) is positioned closer to the main guide bar 151 than to the sub-guide bar 152 in the circumferential direction. The same applies to the STM6. Also, as shown in Figure 8, the main guide bar 151 and sub-guide bar 152, and the main guide bar 161 and sub-guide bar 162 are positioned concentrically when viewed from the direction of the optical axis.

[0044] When the STM5 is driven and the lead screw 502 rotates, the projection 510 moves in the optical axis direction along with the movement of the movable rack 503 in the optical axis direction. At this time, the main guide bar engaging portion 511 is guided by the main guide bar 151 and moves to be positioned in the optical axis OA direction. By positioning the main guide bar 151 and the lead screw 502 of the STM5 close together, play and deflection of the components between the main guide bar 151 and the lead screw 502 can be suppressed. Furthermore, in the case of group 6, when viewed in a plane perpendicular to the optical axis OA between the main guide bar 161 and the sub-guide bar 162, the main guide bar 161 is positioned closer to the STM6 than the sub-guide bar 162.

[0045] Furthermore, the reference numeral 42a in Figure 8 indicates the position of the aperture STM 42a that drives the aperture unit 42. STM 5, STM 6, and the aperture STM 42a are movable in the optical axis direction. As shown in the figure, when viewed from one side of the optical axis OA (front in Figure 8), STM 5 for group 5 and STM 6 for group 6 are positioned so as not to overlap (not interfere with) the aperture STM 42a. In other words, in the circumferential direction, STM 5, STM 6, and the aperture STM 42a are spaced apart in that order. As a result, even if STM 5, STM 6, or the aperture STM 42a moves in the optical axis direction, they will not collide with each other. Note that STM 5, STM 6, and STM 42a may be spaced equally apart. In this case, the weight distribution can be distributed.

[0046] (3. Shape and arrangement of 50-group and 60-group frames) (3-1. Engagement with the guide bar) Figure 10 illustrates the engagement length between the main guide bar engagement portion 511 of the 5-group holder 51 and the main guide bar 151, and the engagement length between the main guide bar engagement portion 622 of the 6-group frame 60 and the main guide bar 151. The main guide bar engagement portion 511 comprises a front wall 511a and a rear wall 511b spaced a predetermined distance apart from each other, and the main guide bar 151 is inserted through a circular guide bar insertion hole 511e provided in each. The front wall 511a and the rear wall 511b may be connected. In other words, the main guide bar engagement portion 511 may be configured to have only one guide bar insertion hole 511e.

[0047] In this specification, the engagement length refers to the length over which a guide bar and an engagement portion that engages with the guide bar are engaged. As described above, the engagement length between the main guide bar engagement portion 511 of the 5-group holder 51 and the main guide bar 151 is the length from the front end of the front wall 511a to the rear end of the rear wall 511b (EL5). The engagement length between the main guide bar engagement portion 611 of the 6-group frame 60 and the main guide bar 161 is the length from the front end of the front wall 611a to the rear end of the rear wall 611b (EL6).

[0048] The engagement of the main guide bar engaging portion 511 with the main guide bar 151 prevents the tilting of the 5-group lens L5. The engagement length EL5 is the range in which, when the 5-group lens L5 moves, the front wall 511a of the main guide bar engaging portion 511 does not come into contact with the rear surface of the front wall portion 44 of the 4-group frame 41, and the rear wall 511b of the main guide bar engaging portion 511 does not come into contact with the front surface of the guide bar retaining member 170. In other words, the engagement length EL5 is limited by the amount of movement of the 5-group lens L5; if the amount of movement of the 5-group lens L5 is large, the engagement length EL5 becomes shorter, and if the amount of movement of the 5-group lens L5 is small, the engagement length EL5 can be made longer. The engagement length EL5 only needs to be long enough to prevent the tilting of the 5-group lens L5. The same applies to the engagement length EL6.

[0049] If the amount of movement of the 6-group lens L6 moved by the STM6 is less than the amount of movement of the 5-group lens L5 moved by the STM5 (in other words, if the amount of movement of the 5-group lens L5 moved by the STM5 is greater than the amount of movement of the 6-group lens L6 moved by the STM6), the engagement length EL6 can be made longer than the engagement length EL5. That is, the engagement length EL6 between the 6-group frame 60 and the main guide bar, which has a small amount of movement in the optical axis direction, can be made longer than the engagement length EL5 between the 5-group frame 50 and the main guide bar. This reduces the inclination of the 5-group lens L5 and 6-group lens L6, which are the focusing lens groups, with respect to the optical axis OA. Note that it is not always necessary to make the engagement length EL6 longer than the engagement length EL5. If the inclination of each lens group with respect to the optical axis OA is sufficiently small, the engagement length can be any length.

[0050] (3-2. Notch) Figure 11 shows the positional relationship between the 5-group frame 50 and the 6-group frame 60 when the focal length is on the telephoto side and the subject distance is at infinity, where the 5-group holder 51 of the 5-group frame 50 and the 6-group hood 62 of the 6-group frame 60 are relatively far apart. Figure 12 shows the positional relationship between the 5-group frame 50 and the 6-group frame 60 when the focal length is on the wide-angle side and the subject distance is at the close side, where the 5-group holder 51 of the 5-group frame 50 and the 6-group hood 62 of the 6-group frame 60 are relatively close together. Figure 13 shows the positional relationship between the 5-group frame 50 and the 6-group frame 60 from a different angle in the same state as in Figure 12, showing where the 5-group holder 51 of the 5-group frame 50 and the 6-group hood 62 of the 6-group frame 60 are close together. As shown in the figure, the 5-group frame 50 is positioned on the inner circumference side of the 6-group frame 60. In other words, when the 5-group frame 50 or the 6-group frame 60 moves in the optical axis direction, there are situations in which the 5-group frame 50 and the 6-group frame 60 are positioned so that at least a portion of them overlap when viewed from a direction perpendicular to the optical axis (radial direction). Specifically, in the state shown in Figure 13, the 5-group frame 50 and the 6-group frame 60 overlap at least a portion of them when viewed from a direction perpendicular to the optical axis.

[0051] As shown in the figures, the 5-group holder 51 is provided with multiple protrusions extending outward, such as the aforementioned protrusion 510 (Figures 11 and 12), the sub-guide bar engagement portion 552 (Figure 13), and other protrusions 560. The other protrusions 560 are, for example, protrusions necessary for assembly when attaching and crimping the 5-group lens L5 to the 5-group holder 51, and are arranged in three locations in the circumferential direction as shown in Figure 8. In other words, the protrusions and projections are convex (protruding) parts that protrude or rise in a direction perpendicular to the optical axis (radial direction).

[0052] In this embodiment, a notch 65 is provided at the end of the 6-group hood portion 62 of the 6-group frame 60 in the direction of the optical axis OA, corresponding to the protrusions (projection portion 510, projection 560, sub-guide bar engagement portion 552, etc.) of the 5-group holding portion 51. Therefore, as shown in Figures 12 and 13, even when the 5-group frame 50 and the 6-group frame 60 are close together, the protrusions of the 5-group holding part 51 (protrusions 510, protrusions 560, sub-guide bar engaging part 552, etc.) do not obstruct the movement of the 6-group frame 60. In other words, the 5-group frame 50 and the 6-group frame 60 do not collide.

[0053] In other words, when the 5-group frame 50 and the 6-group frame 60 are close together, the protrusions of the 5-group holder 51 (protrusions 510, protrusions 560, sub-guide bar engaging portion 552, etc.) fit into the notch 65 of the 6-group frame 60. To put it another way, when the distance between the 5-group frame 50 and the 6-group frame 60 is small (for example, when the 5-group frame 50 and the 6-group frame 60 are closest together, or when the distance between the 5-group frame 50 and the 6-group frame 60 is small), at least one portion of the protrusions of the 5-group holder 51 (protrusions 510, protrusions 560, sub-guide bar engaging portion 552, etc.) and the notch 65 of the 6-group frame 60 overlap in the circumferential direction around the optical axis. This makes it possible to avoid collision between the 5-group frame 50 and the 6-group frame 60. The distance between the 5-group lens L5 and the 6-group lens L6 can be made even closer. Further compactness of the lens barrel 2 as a whole becomes possible. Furthermore, since the 5-group frame 50 and the 6-group frame 60 do not interfere with each other, it becomes possible to increase the relative amount of movement between the 5-group frame 50 and the 6-group frame 60 in the optical axis OA direction, thereby improving the design freedom of the lens groups.

[0054] (Arrangement of 3-3.5 group frames of 50) As shown in Figure 14, the lenses are arranged in the following order from the optical axis: STM5 or STM6 (see Figure 5 for the position of STM6), 5-group lens L5, and 6-group lens L6. In other words, 5-group lens L5 is positioned between STM6 and 6-group lens L6. This allows the lens barrel to be made thinner in the optical axis direction than if the lenses were arranged in the following order from the optical axis: 5-group lens L5, STM6, and 6-group lens L6.

[0055] (4. Food) Figure 14 is a cross-sectional view of a portion of the lens barrel 2, showing the state where the 4-group lens L4 and the 5-group lens L5 are close together. When the 4-group lens L4 and the 5-group lens L5 are close together, the 5-group frame 50 (or the 5-group hood part 52) ​​overlaps the 4-group frame 41 (or the 4-group lens L4 or the 4-group holder part 43). In other words, when the 5-group lens L5 is closest to the 4-group lens L4, the 4-group frame 41 (or the 4-group lens L4 or the 4-group holder part 43) and the 5-group frame 50 (or the 5-group hood part 52) ​​overlap at least partially when viewed in the radial direction centered on the optical axis. That is, the 4-group frame 41 and the 5-group frame 50 overlap at least partially on the optical axis. The diameter of the 5-group hood part 52 is larger than the diameter of the 4-group lens L4. Figure 15 is a magnified view of the 4-group lens L4 and the 5-group hood section 52, showing the state in which the 5-group hood section 52 does not cover the 4-group frame 41. In other words, it shows the state in which the 4-group frame 41 and the 5-group frame 50 do not overlap in the radial direction.

[0056] Similarly, the 6-group frame 60 and the 7-group frame 70 also include the 6-group hood section 62 and the 7-group hood section 72. Specifically, when the 5-group lens L5 and the 6-group lens L6 are close together, the 6-group frame 60 (or the 6-group hood 62) overlaps the 5-group frame 50 (or the 5-group lens L5 or the 5-group holder 51). In other words, when the 5-group lens L5 and the 6-group lens L6 are closest together, at least a portion of the 5-group frame 50 and the 6-group frame 60 overlap radially. That is, at least a portion of the 5-group frame 50 and the 6-group frame 60 overlap on the optical axis. The diameter of the 6-group hood 62 is larger than the diameter of the 5-group lens L5. Furthermore, when the 6-group lens L6 and the 7-group lens L7 are close together, the 7-group frame 70 (or the 7-group hood 72) overlaps the 6-group frame 60 (or the 6-group lens L6 or the 6-group holder 61). In other words, when the 6-group lens L6 and the 7-group lens L7 are closest together, the 6-group frame 60 and the 7-group frame 70 overlap at least partially when viewed radially. That is, the 6-group frame 60 and the 7-group frame 70 overlap at least partially on the optical axis. The diameter of the 7-group hood 72 is larger than the diameter of the 6-group lens L6.

[0057] As shown in the diagram, the hood sections 52 (group 5), 62 (group 6), and 72 (group 7) extend forward from the lenses L5 (group 5), L6 (group 6), and L7 (group 7), respectively, thereby preventing ghosting caused by stray light. Note that each hood section may also extend backward. As shown in Figure 5, the motor sliding cylinder 100 covers the outer circumference of the 5-group lens L5 and the 6-group lens L6. However, the motor sliding cylinder 100 is provided with multiple holes for attaching photointerrupters, STM5, STM6, etc. It is also provided with multiple holes for screw fastening to attach these components. Because the motor sliding cylinder 100 has multiple holes, subject light may leak out and travel to the outside of the motor sliding cylinder 100, or light may enter through the holes and mix with the subject light as stray light, potentially degrading the captured image.

[0058] For example, when there are two STMs fixed to the motor sliding cylinder 100, there are more holes for mounting the STMs than when there is one, which increases the possibility of image degradation such as ghosting.

[0059] However, by providing the 5-group hood section 52, the 6-group hood section 62, and the 7-group hood section 72, it is possible to prevent the captured image from degrading due to stray light. In this embodiment, the 5-group hood section 52 is shown as separate from the 5-group holder section 51, the 6-group hood section 62 is shown as integrated with the 6-group holder section 61, and the 7-group hood section 72 is shown as integrated with the 7-group holder section 71, but the hood and lens frame may be integrated or separate.

[0060] The lens hood sections 52 (group 5), 62 (group 6), and 72 (group 7) surround the lens group at the front in the optical axis OA direction with the hood of the rear lens group when the lens group moves in the optical axis OA direction.

[0061] As shown in Figure 14, the diameters of the hood sections for group 5 (52), group 6 (62), and group 7 (72) increase in that order. Furthermore, if there is a protrusion on the outer diameter side of the hood portion located on the inner diameter side, a recess (relief portion) is provided in the outer diameter side of the hood portion to accommodate the protrusion. For example, a protrusion 43a is provided on the outer circumference of the 4-group holder portion 43 as shown in Figure 15, and a recess (groove) 52b corresponding to the protrusion 53a is provided in the 5-group hood portion 52 on the outer diameter side. Since the protrusion 53a can be accommodated by the recess 52b, collision between the 4-group holder portion 43 and the 5-group hood portion 52 can be prevented. In addition, the 5-group hood portion 52 can cover the 4-group holder portion 43, preventing light leakage from the subject and deterioration of the captured image due to stray light, etc. Similarly, if there is a protrusion on the outer diameter side of the 5-group holder frame 50, a recess may be provided in the 6-group hood portion 62. If there is a protrusion on the outer diameter side of the 6-group frame 60, a recess may be provided in the 7-group hood portion 72. Note that it is not limited to a recess (groove), but may also be a notch, for example. Also, it is not necessary for all hood portions to have recesses (grooves). Furthermore, the depression (groove, relief section) 52b may be present around the entire circumference or only on a part of the circumference.

[0062] Furthermore, the inner surfaces of the 5th group hood section 52, the 6th group hood section 62, and the 7th group hood section 72 are provided with circumferentially extending light-shielding features (light-shielding lines 52a, 62a, and 72a). The light-shielding lines may be grooves or steps. Furthermore, light-shielding lines may be provided in all of the hood sections for groups 5 (52), 6 (62), and 7 (72), or some hoods may not have light-shielding lines.

[0063] Furthermore, as can be seen from Figure 14, the components are arranged in the following order from the subject side along the optical axis: STM5 or STM6 (see Figure 5 for the position of STM6), 5-group lens L5, and 6-group lens L6. As shown in the figure, the 5-group lens L5 has a smaller diameter than the 6-group lens L6. In other words, in this embodiment, the components are arranged in the following order from the subject side along the optical axis: STM, small-diameter lens (5-group lens L5), and large-diameter lens (6-group lens L6). Therefore, the diameter of the 6-group hood 62 is larger than the diameter of the 5-group lens L5.

[0064] As described above, the 5-group lens hood section 52 extends forward from the 5-group lens L5, and the 6-group lens hood section 62 extends forward from the 6-group lens L6. When the 5-group lens L5 and the 6-group lens L6 move in the direction of the optical axis OA, the 5-group lens hood section 52 and the 6-group lens hood section 62 also move. As shown in Figure 14, when the 5-group lens L5 is close to the STM5 (or STM6), the 5-group hood section 52 may be positioned on the inner diameter side of the STM5 (or STM6).

[0065] In this case, since the diameter of the 5-group lens L5 is small, even considering the situation where the 5-group hood section 52 is positioned on the inner diameter side of the STM5 (or STM6), the overall outer diameter of the lens barrel 2 does not need to be increased.

[0066] Furthermore, STM5 (or STM6) is positioned on the outer circumference of the 4-group lens L4, which is located even further forward than the 5-group lens L5. The 4-group lens L4 has an even smaller diameter than the 5-group lens L5, and the outer diameter of the 4-group holder 43 is even smaller than that of the 5-group hood 52. In other words, the diameter of the 5-group hood 52 is larger than the diameter of the 4-group lens L4. In other words, multiple lens groups are arranged in the direction of the optical axis OA, with the diameter increasing sequentially, and STM5 (or STM6) is positioned on the outer circumference of the smallest lens group among them, the 4-group lens L4. According to this design, the STM5 (or STM6) is positioned on the outer diameter side of the smallest lens group, the 4-group lens L4, and the 5-group hood section 52, which has a larger diameter than the 4-group lens L4, can be placed in the gap between the 4-group lens L4 and the STM5. Therefore, the distance between the 4-group lens L4 and the 5-group lens L5 can be brought closer, making it possible to reduce the size in the optical axis OA direction or the radial direction.

[0067] Furthermore, a 4-group lens L4 is positioned after the aperture unit 42. The lens group that comes after the aperture unit 42 is often smaller than the other lens groups. Therefore, by arranging the lenses in the order of aperture unit 42, smallest diameter lens (4-group lens L4), small diameter lens (5-group lens L5), and large diameter lens (6-group lens L6) from the subject side along the optical axis, and by placing the STM5 (or STM6) on the outer diameter side of the smallest diameter lens (4-group lens L4), the lens barrel 2 can be made more compact. Furthermore, it is not necessary for all of the 5-group frame 50, 6-group frame 60, and 7-group frame 70 to be equipped with a hood. One or two of the 5-group frame 50, 6-group frame 60, and 7-group frame 70 may be equipped with a hood. It should be noted that while it was stated that the rear lens hood overlaps with the front lens hood when the front and rear lens groups are closest together, this is not the only case. The hood only needs to be long enough to prevent image degradation, and it does not necessarily need to overlap.

[0068] (5. Photointerrupter) As shown in Figure 5, the motor sliding cylinder 100 is fitted with a 5-group photointerrupter PI5 and a 6-group photointerrupter PI6 (only the 5-group version is shown in Figure 5). The 5-group photointerrupter PI5 will be described below. The description of the 6-group photointerrupter PI6 is the same as that of the 5-group photointerrupter PI5, so the description will be omitted.

[0069] As shown in Figure 6, etc., the 5-group photointerrupter PI5 is positioned so that the light-shielding portion 512 can pass between the light-emitting portion and the light-receiving portion of the 5-group photointerrupter PI5 when the 5-group lens L5 is driven by the 5-group lens drive unit 500. The light-shielding portion 512 is positioned on the outer diameter side of the 5-group lens L5 on the optical axis OA in order to perform position detection.

[0070] By the way, the position of the lens group when camera body 3 is powered on is not fixed, as it depends on the state when the power was turned off. Therefore, the position of each lens group when camera body 3 is powered on is not fixed, and it is unknown where they are located. Therefore, using the 5-group lens L5 as an example, first, the STM5 is driven by a drive command from the control unit 90 of the main board 88 to move the 5-group frame 50. Then, the 5-group lens L5 is detected by passing the light-shielding part 512 provided on the 5-group holding part 51 between the light-emitting part and the light-receiving part of the 5-group photointerrupter PI5. The position of the 5-group lens L5 when the light-shielding part 512 passes through (shiels) PI5 is used as the reference position, and the 5-group lens L5 is moved accordingly. In other words, the 5-group photointerrupter PI5 is positioned at the reference position of the 5-group lens L5. Hereafter, the reference position of the 5-group lens L5 will be called the 5-group origin position. The same applies to the 6-group lens.

[0071] The 5-group L5 lens moves to a reference position (origin position) and then to an initial position. The initial position is set to the infinity end of the set focal length (for example, the infinity end). Setting the initial position to infinity allows for the display of a through image with less blur. Also, when shooting with the focus position (shooting distance) set to infinity, the user does not need to change the shooting distance after the initial operation.

[0072] Figure 16 is a flowchart illustrating the initial operation of the control unit 90 of the lens barrel 2. This flowchart starts when the user turns on the power to the camera body 3. In S01, the control unit 90 detects that the camera body 3 has been powered on and proceeds to S02. In S02, the control unit 90 drives the STM6 to move the 6-group frame 60 (6-group lens L6) in the optical axis direction, and proceeds to S03. In S03, the control unit 90 determines whether the 6-group lens L6 has moved to the 6-group origin position. As described above, the control unit 90 can determine this by detecting whether PI6 is shielded by the light-shielding section 612. If the control unit 90 determines that the 6-group lens L6 has moved to the 6-group origin position, the process proceeds to S04. Otherwise, the process returns to S02, and steps S02 and S03 are repeated until it is determined that the 6-group lens L6 has moved to the 6-group origin position. In S04, the control unit 90 drives the STM5 to move the 5-group frame 50 (5-group lens L5) in the optical axis direction. Proceed to S05. In S05, the control unit 90 determines whether the 5-group lens L5 has moved to the 5-group origin position. As described above, the control unit 90 can determine this by detecting whether PI5 is shielded by the light-shielding unit 512. If the control unit 90 determines that the 5-group lens L5 has moved to the 5-group origin position, the process proceeds to S06. Otherwise, the process returns to S04, and steps S04 and S05 are repeated until it is determined that the 5-group lens L5 has moved to the 5-group origin position.

[0073] In S06, the control unit 90 drives the STM6 to move the 6-group frame 60 (6-group lens L6) to the initial position of the 6-group. As described above, the initial position of the 6-group is the infinity position at the set focal length. For example, if the positions of L1-L4, motor sliding cylinder 100, and L7 are at the wide-angle end due to the zoom ring 81, the control unit 90 drives the STM6 to move the 6-group lens L6 to the infinity position (W∞) at the wide-angle end. Proceed to S07. In S07, the control unit 90 drives the STM5 to move the 5-group frame 50 (5-group lens L5) to the initial position of the 5-group. The initial position of the 5-group is also set to the infinity position at the set focal length. When S07 is executed, the control unit 90 terminates its initial operation. Note that while the initial position is set to the infinity position at the specified focal length, it is not necessarily limited to this. For example, it could be the closest position (e.g., the nearest end) at the specified focal length, or a position between infinity and the nearest end.

[0074] By changing the position of PI (origin), the time required for the initial operation shown in Figure 16 can be shortened or averaged.

[0075] Let me explain in detail. Figure 17 illustrates the position of the 5-group photointerrupter PI5 on the optical axis OA and the position of the 6-group photointerrupter PI6. Below, I will explain the 5-group and 6-group lenses together. In Figure 17, the nearest point (TN) position at the telephoto end of the 5-group lens L5 and the nearest point (TN) position at the telephoto end of the 6-group lens L6 are shown at the same position in the optical axis direction, but in reality they are different. The TN position of the 5-group lens L5 is in front of (towards the subject, towards the object) the TN position of the 6-group lens L6 in the optical axis direction. When the shooting distance is changed while the focal length is at its telephoto end, L5 and L6 move between the nearest (TN) position at the telephoto end and the infinity (T∞) position at the telephoto end. When the shooting distance is changed while the focal length is at its wide-angle end, L5 and L6 move between the nearest (WN) position at the wide-angle end and the infinity (W∞) position at the wide-angle end. Therefore, when the power is turned ON at S1 in Figure 16, L5 and L6 are positioned at any location between TN and W∞. Therefore, by placing the photo interrupter PI5 (or PI6) at any position within the movement range of the 5-group frame 50 (or 6-group frame 60) from TN to W∞, the time required for initial operation can be shortened or averaged. Note that Figure 17 shows an example where the nearest end is closer to the subject than the nearest end, but the infinite end may also be closer to the subject than the nearest end. In this case, the photo interrupter PI5 (or PI6) should be placed at any position within the movement range of the 5-group frame 50 (or 6-group frame 60) from T∞ to WN.

[0076] The following describes three different configurations for the photointerrupter PI5 or PI6.

[0077] (1) Place the photo interrupter at the position shown in (1) in Figure 17. In other words, the photo interrupter PI5 or PI6 is positioned between the infinity position (T∞) at the telephoto end and the infinity position (W∞) at the wide-angle end. To put it another way, PI5 (or PI6) is positioned at any position within the movable range of the 5-group lens L5 (or 6-group lens L6) when the focal length is changed while the shooting distance is set to infinity, and detects the 5-group frame 50 (or 6-group frame 60). This reduces the time required to move from the origin position to the initial position. Alternatively, the photo interrupter PI5 or PI6 may be positioned in the center between T∞ and W∞. To put it another way, PI5 (or PI6) is positioned in the center within the movable range of the 5th lens L5 (or 6-group lens L6) when the focal length is changed while the shooting distance is set to infinity, and detects the 5-group frame 50. The center does not have to be exactly in the center; it may be shifted to some extent forward or backward. For example, it can be positioned within the middle range when the distance from T∞ to W∞ is divided into three equal parts. Alternatively, it can be placed within a range that includes a predetermined length in front of and behind the center (for example, 3mm in front and 3mm behind). In this case, regardless of the set focal length, the time it takes to move L5 or L6 from the origin to the initial position can be averaged. Note that while Figure 17 shows an example where the nearest end is closer to the subject than the infinity end, the infinity end may also be closer to the subject than the nearest end.

[0078] (2) Place the photo interrupter at the position shown in (2) of Figure 17. In other words, the photo interrupter PI5 or PI6 is positioned near the infinity (T∞) position at the telephoto end. To put it another way, PI5 (or PI6) is positioned near the position where the 5-group frame 50 (or 6-group frame 60) is positioned when the shooting distance is at infinity and the focal length is at the telephoto end. Being near T∞ does not mean it is exactly at the T∞ position; it may be shifted forward or backward to some extent. For example, it can be positioned within a range that includes a predetermined length in front of and behind the T∞ position (e.g., 3mm forward and 3mm backward). For example, if the lens barrel is shortest when the focal length is at its telephoto end, it is likely that the photographer will often set the lens barrel 2 to its telephoto end when not taking pictures (e.g., when the power is off) in order to shorten it. In this case, it is likely that the power will be turned on with the lens barrel at its telephoto end, so the initial position is likely to be T∞. Therefore, if PI5 or PI6 is placed at the position (T∞) shown in (2), the origin position and the initial position will be the same, thus reducing the time it takes to move L5 or L6 from the origin position to the initial position. Also, even if the lens barrel 2 is not at its telephoto end when the power is turned on, if it is on the telephoto side, the origin position and the initial position will be close together, so the time it takes to move L5 or L6 from the origin position to the initial position can be reduced. As a result, the overall initial operation time of camera 1 can be reduced.

[0079] Furthermore, the position of L5 or L6 when the camera body 3 is powered on (the position of L5 or L6 in S01 in Figure 16) is one of the positions within the range in which L5 or L6 can move (for example, between TN and W∞ in Figure 17). In other words, when the power is turned on, the control unit 90 must move L5 or L6 from one of the positions within the range in which L5 or L6 can move to the position of the photo interrupter PI5 or PI6 (the origin position). Therefore, by placing PI5 or PI6 at the position shown in (2), the time taken from power-on to origin position detection can be averaged or shortened. Note that in the case of a lens with a movable range like L6, the photo interrupter may be placed in the center of the movable range rather than near T∞. As with the above, the center does not have to be exactly the center. Note that while Figure 17 shows an example where the nearest focus point is closer to the subject than the infinity focus point, the infinity focus point may also be closer to the subject than the nearest focus point. In this case, the photo interrupter PI5 or PI6 may be placed at the nearest focus (TN) position of the telephoto end.

[0080] (3) Place the photo interrupter at the position shown in (3) of Figure 17. In other words, the photo interrupter PI5 or PI6 is positioned near the infinity (W∞) position at the wide-angle end. To put it another way, PI5 (or PI6) is positioned where the 5-group frame 50 (or 6-group frame 60) is positioned when the shooting distance is at infinity and the focal length is at the wide-angle end. "Near W∞" does not have to be exactly at the W∞ position; it may be shifted forward or backward to some extent. For example, it may be positioned within a range that includes a predetermined length in front of and behind the W∞ position (e.g., 3mm forward and 3mm backward). For example, if the lens barrel is shortest when the focal length is at its wide-angle end, it is likely that the photographer will often set the lens barrel 2 to its wide-angle end when not taking pictures (e.g., when the power is off) in order to shorten it. In this case, it is likely that the power will be turned on while the lens barrel is at its wide-angle end, so the initial position is likely to be W∞. Therefore, if PI5 or PI6 is placed at the position shown in (3) (W∞), the origin position and the initial position will be the same, thus reducing the time it takes to move L5 or L6 from the origin position to the initial position. Also, even if the lens barrel 2 is not at its wide-angle end when the power is turned on, if it is on the wide-angle side, the origin position and the initial position will be close together, thus reducing the time it takes to move L5 or L6 from the origin position to the initial position. As a result, the overall initial operation time of camera 1 can be reduced.

[0081] Note that both PI5 and PI6 may be placed in (1) to (3) above, or either one of them may be placed in (1) to (3) above.

[0082] Furthermore, although the above explanation uses the position of infinity at the set focal length as the initial position, this is not the only option. For example, the position of the nearest focal length could be used as the initial position. In that case, (1A) PI is placed between TN and WN. More specifically, PI is placed in the central range between TN and WN. (2A) PI is placed near TN. (3A) PI is placed near WN. These are some possible options. Furthermore, as explained in (2) above, the PI may be positioned to detect any position within the range of movement of the lens. In other words, PI5 (or PI6) detects that the 5th lens L5 (or 6th lens group L6) is positioned at any position (origin position) within the range of movement of the 5th lens L5 (or 6th lens group L6). For example, any position could be the center of the range of movement of the 5th lens group L5 (or 6th lens group L6). As with the above, it does not have to be exactly in the center. Note that while Figure 17 shows an example where the closest focusing end is closer to the subject than the infinity focusing end, the infinity focusing end may also be closer to the subject than the closest focusing end. In this case, the range in which the 5-group lens L5 or the 6-group lens L6 can move is from the closest focusing end at the wide-angle end to infinity at the telephoto end.

[0083] (6. Remove any looseness) Returning to Figure 2, let's explain how to eliminate the play in the motor sliding cylinder 100. As shown in the figure, a coil spring 171 is positioned as an elastic member between the rear end surface of the motor sliding cylinder 100 in the optical axis direction OA and the front end surface of the guide bar retaining member 170. The front end surface of the guide bar retaining member 170 may be flat. Note that a tension spring or other pressing member may be used instead of the coil spring 171. Also, although the rear end of the motor sliding cylinder 100 is spring-biased in Figure 2, this is not the only option. A spring or pressing member may be positioned between the front end (front surface) of the motor sliding cylinder 100 and the 4-group frame. By biasing the motor sliding cylinder 100 in the optical axis direction with the coil spring 171, the effect of play can be reduced. Since the cam pin 101 is pressed against the side surface of the circumferential groove 83a of the inner cam cylinder 83, play is eliminated, so the positioning of the motor sliding cylinder 100 in the optical axis direction OA can be performed with high precision. In other words, the cam pin 101 is pressed against one side of the circumferential groove (cam groove) 83a of the inner cam cylinder 83 by the coil spring 171, so play can be eliminated. Furthermore, as shown in Figure 2, the cam pin 101 and the coil spring 171 are arranged along the optical axis on a plane parallel to the optical axis. This ensures that the circumferential positions of the cam pin 101 and the coil spring 171 coincide, allowing for efficient biasing. Note that multiple cam pins 101 and coil springs 171 may be provided. For example, three sets may be arranged along the circumferential direction.

[0084] While we have described how lens group L5 and lens group L6 are moved in the optical axis direction by the STM, this is not the only case. For example, lenses from other groups may also be moved in the optical axis direction by the STM.

[0085] Although it has been described that the motor sliding cylinder 100 moves in the optical axis direction in mechanical linkage with the zoom ring 81, it is not limited to this configuration. For example, a motor that rotates the outer cam cylinder 82 or the inner cam cylinder 83 may be provided, and the motor may rotate the outer cam cylinder 82 or the inner cam cylinder 83 during zooming or focusing, causing the motor sliding cylinder 100 to move in the optical axis direction.

[0086] The motor sliding cylinder 100 has the STM5, STM6, PI5, and PI6 fixed to it. By fixing the components for driving the 5-group lens L5 and 6-group lens L6, which are the focusing lenses, to a single cylinder in this way, errors such as play between the 5-group lens L5 and 6-group lens L6 are less likely to occur. Therefore, higher performance focus control can be achieved.

[0087] Furthermore, since the motor sliding cylinder 100 can move in the optical axis direction, the 5-group lens L5 and 6-group lens L6 can be moved more in the optical axis direction without lengthening the STM's lead screw. Specifically, the 5-group lens L5 and 6-group lens L6 are moved in the optical axis direction by the motor sliding cylinder 100 and the STM. This allows the STM's lead screw to be shortened compared to when the 5-group lens L5 and 6-group lens L6 are moved by the STM alone. Therefore, play due to lead screw tilting can be reduced. [Explanation of Symbols]

[0088] L1: 1-group lens, L2: 2-group lens, L3: 3-group lens, L4: 4-group lens, L5: 5-group lens, L6: 6-group lens, L7: 7-group lens, OA: Optical axis, PI5: Photo interrupter for 5-group lens, PI6: Photo interrupter for 6-group lens, STM5: Motor for 5-group lens, STM6: Motor for 6-group lens 1: Camera, 2: Lens barrel, 3: Camera body, 4: Image sensor, 11:1 group frame, 12:1 group sliding tube, 21:2 group frame, 31:3 group frame, 41: 4-group frame, 43: 4-group holder, 44: front wall, 45: cylindrical part, 45a: straight groove, 42: aperture unit, 42a: STM for aperture, 50: 5-group frame, 51: 5-group holder, 52: 5-group hood, 52a: light-shielding wire, 60: 6-group frame, 61: 6-group holder, 62: 6-group hood, 62a: light-shielding line, 65: notch, 70: 7-group frame, 71: 7-group holder, 72: 7-group hood, 72a: light shielding wire, 73: 7-group sliding cylinder, 81: Zoom ring, 82: Outer cam cylinder, 83: Inner cam cylinder, 83a: Circumferential groove, 84: Outer fixing cylinder, 84a: Photo interrupter, 85: Inner fixing cylinder, 86: Focus ring, 86a: Reflective tape, 86b: Light-shielding line, 88: Main board, 90: Control unit, 91: First connecting pin, 92: Second connecting pin, 100: Motor sliding cylinder, 101: Cam pin, 151: Main guide bar, 152: Sub guide bar, 161: Main guide bar, 162: Sub guide bar, 170: Guide bar retaining member, 171: Coil spring 500: 5-group lens drive unit, 501: unit frame, 501a: unit fixing part, 501b: fixing part, 501c: lead screw holding part, 502: lead screw, 503: movable rack, 504: meshing part, 505: engaging shaft part, 505a: rear small diameter part, 505b: medium diameter part, 505c: large diameter part, 505d: front small diameter part, 506: coil spring, 510: protrusion, 511: main guide bar engaging part, 511a: front wall, 511b: rear wall, 511c: side wall, 511d: side wall, 511e: guide bar insertion hole, 512: light shielding part, 513: rack engaging part, 513a: front arm, 513b: rear arm, 513d: through hole, 513e: through hole, 552: sub guide bar engaging part, 560: projection, 600: 6-group lens drive unit, 610: protruding part, 611: main guide bar engagement part, 611a: front wall, 611b: rear wall, 612: light shielding part, 622: main guide bar engagement part, 652: sub-guide bar engagement part

Claims

1. A first lens holding frame that holds the first lens and has a projection that protrudes in a direction intersecting the optical axis, A first drive unit moves the first lens holding frame in the optical axis direction, A first guide bar engages with the aforementioned projection and guides the first lens holding frame in the optical axis direction, A second lens holding frame holds a second lens arranged alongside the first lens along the optical axis, and has a first hood portion extending from a part of the outer circumference of the second lens toward the first lens holding frame, A second drive unit moves the second lens holding frame in the optical axis direction, Equipped with, As the first lens retaining frame and the second lens retaining frame approach each other, at least a portion of the protrusion is located in a region extending from a portion of the outer circumference of the second lens toward the first lens retaining frame, in a region where the first hood portion is not provided in the circumferential direction centered on the optical axis. Lens barrel.

2. When the first lens retaining frame and the second lens retaining frame approach each other, the first lens retaining frame is positioned on the inner circumference side of the first hood portion. The lens barrel according to claim 1.

3. The first hood portion is formed along the circumferential direction centered on the optical axis, The surface of the first hood portion facing the optical axis is provided with light-shielding lines extending in the circumferential direction. The lens barrel according to claim 1 or 2.

4. The first lens and the second lens are opposite each other in the optical axis direction, A lens barrel according to any one of claims 1 to 3.

5. The first lens and the second lens are focusing lenses. A lens barrel according to any one of claims 1 to 4.

6. The first lens retaining frame has a second hood portion that extends toward the second lens retaining frame along the optical axis direction. A lens barrel according to any one of claims 1 to 5.

7. The first lens retaining frame is positioned on the object side of the second lens retaining frame in the optical axis direction. A lens barrel according to any one of claims 1 to 6.

8. The first lens holding frame is guided in the optical axis direction and includes a second guide bar different from the first guide bar, A lens barrel according to any one of claims 1 to 7.

9. The second drive unit comprises a lead screw and a stepping motor. The distance between the lead screw and the second guide bar is smaller than the distance between the lead screw and the first guide bar. The lens barrel according to claim 8.

10. The first drive unit has a voice coil motor. The lens barrel according to claim 9.

11. The second lens holding frame is provided with a third guide bar that guides it in the optical axis direction, The second guide bar is a shared guide bar that guides the first lens retaining frame and the second lens retaining frame in the optical axis direction. A lens barrel according to any one of claims 8 to 10.

12. The first cylinder comprises at least a portion of the first drive unit and at least a portion of the second drive unit, A lens barrel according to any one of claims 1 to 11.

13. The first cylinder is provided with an opening in which at least a part of the first drive unit is arranged. The first hood portion reduces at least one of the intrusion of light into the opening and the outflow of light from the opening. The lens barrel according to claim 12.

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