Lens barrel and imaging device

Abstract

A lens barrel includes: a first lens holding frame holding a first lens and having a first protrusion; a first motor moving the first lens holding frame in an optical axis direction; a second lens holding frame holding a second lens and having a second protrusion; a second motor moving the second lens holding frame in the optical axis direction; and an outer tube engaged with the first protrusion and the second protrusion, having a straight groove extending in the optical axis direction, and disposed at an outer periphery side compared with the first lens holding frame and the second lens holding frame.

Description

Technical Field

[0001] The invention relates to a lens barrel and a camera device. Background Art

[0002] A lens barrel in which a plurality of lens groups are driven individually by independent actuators has been proposed (for example, Patent Document 1). In addition, high-precision movement of the plurality of lens groups is desired.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-32565 Summary of the Invention

[0006] According to the first aspect, the lens barrel comprises: a first lens holding frame that holds a first lens and has a first protrusion; a first motor that moves the first lens holding frame in the optical axis direction; a second lens holding frame that holds a second lens and has a second protrusion; a second motor that moves the second lens holding frame in the optical axis direction; and an outer barrel that has a straight groove that engages with the first protrusion and the second protrusion and extends in the optical axis direction, and is arranged on the outer peripheral side compared to the first lens holding frame and the second lens holding frame.

[0007] According to a second aspect, an imaging device includes the above-described lens barrel.

[0008] In addition, the configuration of the embodiments described below may be appropriately modified, or at least a portion thereof may be replaced with another configuration. Furthermore, the components whose configuration is not particularly limited are not limited to the configuration disclosed in the embodiments, and may be configured at positions where their functions can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a cross-sectional view of a lens barrel according to one embodiment.

[0010] Figure 2 (A) is a partial cross-sectional perspective view showing the relationship between the second fixed cylinder, the first lens holding frame, and the second lens holding frame. Figure 2 (B) is from Figure 2 This is a partial cross-sectional view of the second fixed cylinder when viewed in the direction indicated by arrow A10 in (A).

[0011] Figure 3 yes Figure 2 (B) AA line cross-sectional view.

[0012] Figure 4 (A) and Figure 4 (B) is Figure 3BB line cross-sectional view.

[0013] Figure 5 (A) is in Figure 1 A schematic perspective view of the second fixed cylinder viewed from the direction indicated by arrow A12, Figure 5 (B) is an enlarged view of the first driving source unit.

[0014] Figure 6 (A) is an enlarged view of the rack holding mechanism. Figure 6 (B) is from Figure 6 FIG. 1 is a diagram showing the rack holding mechanism viewed from the direction indicated by arrow A1 in FIG. 1 .

[0015] Figure 7 (A) is Figure 6 (B) AA line cross-sectional view, Figure 7 (B) is Figure 6 (B) BB line cross-sectional view, Figure 7 (C) is Figure 6 (B) CC line cross-sectional view.

[0016] Figure 8 (A) is an enlarged view of the frame side of the shaft holding portion. Figure 8 (B) is a side view of the rack.

[0017] Figure 9 (A) and Figure 9 (B) is a diagram showing an example of arrangement of the first protrusion and the second protrusion in the linear groove of Modification 1.

[0018] Figure 10 This is a diagram showing an example of arrangement of the first protrusion and the second protrusion in the linear groove of Modification 2.

[0019] Figure 11 (A) and Figure 11 (B) is a diagram showing an example of arrangement of the first protrusion and the second protrusion in the linear groove of Modification 3.

[0020] Figure 12 (A) and Figure 12 (B) is a diagram for explaining a frame according to a modified example. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments will be described with reference to the drawings. Figure 1 1 is a diagram showing a camera 1 including a lens barrel 100 and a camera body 101 according to this embodiment. Figure 2 (A) is a partial cross-sectional perspective view showing the relationship between the second fixed cylinder 20, the first lens holding frame F1, and the second lens holding frame F2, which will be described later. Figure 2 (B) is from Figure 2 A partial cross-sectional view of the second fixed cylinder 20 when viewed from the direction indicated by arrow A10 in (A). Figure 3 yes Figure 2 (B) AA line cross-sectional view.

[0022] Furthermore, in this embodiment, the lens barrel 100 is attachable to and detachable from the camera body 101 , but the present invention is not limited thereto, and the lens barrel 100 and the camera body 101 may be integrally formed.

[0023] like Figure 1 As shown, the lens barrel 100 of this embodiment includes a first fixed barrel 10, a second fixed barrel 20 arranged on the inner peripheral side of the first fixed barrel 10, and a focus ring 15 arranged on the outer peripheral side of the first fixed barrel 10. In this embodiment, the first fixed barrel 10 is composed of multiple parts, but it can also be composed of a single part. Figure 1 As shown, a lens mount 13 that allows the lens barrel 100 to be attached to and detached from a camera body 101 is fixed to the first fixed cylinder 10 .

[0024] The lens barrel 100 includes a plurality of lens groups including a first lens group L1 and a second lens group L2 arranged in sequence along a common optical axis OA. The first lens group L1 and the second lens group L2 are each a focusing lens group.

[0025] The first lens group L1 is held by a first lens holding frame F1 , the second lens group L2 is held by a second lens holding frame F2 , and the other lens groups are held by a first fixed tube 10 .

[0026] Although detailed later, the first lens holding frame F1 and the second lens holding frame F2 are driven by a first drive source unit 60 and a second drive source unit 70, respectively. For example, a stepping motor, a voice coil motor, or an ultrasonic motor can be used as the first drive source unit 60 or the second drive source unit 70. Thus, for example, the first lens holding frame F1 and the second lens holding frame F2 can be individually or collectively moved linearly in the direction of the optical axis OA in response to operation of the focus ring 15.

[0027] The first lens holding frame F1 and the second lens holding frame F2 are as shown in FIG. Figure 2 As shown in (A), it is arranged inside the second fixed cylinder 20. Figure 1 as well as Figure 2 As shown in FIG. 2A , the second fixed cylinder 20 has a plurality of (three in this embodiment) linear grooves 21 extending in the optical axis OA direction, and a hole 22 extending in the optical axis OA direction through the second fixed cylinder 20 .

[0028] In this embodiment, the first and second lens holding frames F1 and F2, which house the second fixed barrel 20, have no openings penetrating through the walls (connecting the inside and outside of the walls) other than the hole 22. This prevents light leakage from the outside to the inside of the second fixed barrel 20 and facilitates countermeasures against light leakage. Furthermore, the strength of the second fixed barrel 20 is improved.

[0029] like Figure 3 As shown, the first lens holding frame F1 has a first protrusion 31 that protrudes in a direction intersecting the optical axis OA, and the second lens holding frame F2 has a second protrusion 41 that protrudes in a direction intersecting the optical axis OA. The first protrusion 31 and the second protrusion 41 engage with the linear groove 21 of the second fixed cylinder 20. More specifically, the first protrusion 31 and the second protrusion 41 abut against each other, and while in contact, the first protrusion 31 and the second protrusion 41 engage with the linear groove 21.

[0030] A block portion 50 is provided between the first protrusion 31 and the wall 21a of the linear groove 21, abutting against the wall 21a. The block portion 50 moves integrally with the first lens retaining frame F1 (first protrusion 31) in the direction of the optical axis OA, but is assembled to the first lens retaining frame F1 so as to be movable relative to the first protrusion 31 in a circumferential direction centered on the optical axis OA. The first protrusion 31, the second protrusion 41, and the block portion 50 engage with the linear groove 21, thereby restricting the rotation of the first lens retaining frame F1 and the second lens retaining frame F2 about the optical axis OA. The first lens retaining frame F1 and the second lens retaining frame F2 are guided by the linear groove 21 and move linearly in the direction of the optical axis OA.

[0031] Here, use Figure 4 (A) and Figure 4 (B) describes the relationship between the second fixed cylinder 20 , the first protrusion 31 of the first lens holding frame F1 , the second protrusion 41 of the second lens holding frame F2 , and the block portion 50 .

[0032] Figure 4 (A) and Figure 4 (B) is Figure 3 BB line cross-sectional view, Figure 4 (A) shows the state where the first lens group L1 and the second lens group L2 are separated the farthest in the direction of the optical axis OA. Figure 4 (B) shows the state where the first lens group L1 and the second lens group L2 are closest to each other in the direction of the optical axis OA. Figure 4 (A) and Figure 4 In (B), illustration of the main body of the first lens holding frame F1 and the main body of the second lens holding frame F2 is omitted.

[0033] like Figure 4 (A) and Figure 4 As shown in FIG. 5B , a compression spring 51 for urging the first protrusion 31 and the block 50 in a direction separating the first protrusion 31 and the block 50 is provided between the first protrusion 31 and the block 50. The compression spring 51 may be another urging member such as a leaf spring.

[0034] The compression spring 51 presses the block portion 50 against the wall 21a of the linear groove 21, and biases the first protrusion 31 relative to the second protrusion 41. This suppresses slack in the first lens retaining frame F1 and the second lens retaining frame F2 during independent movement (slack between the first lens retaining frame F1 and the second lens retaining frame F2) and enables each of the first lens retaining frame F1 and the second lens retaining frame F2 to move within the linear groove 21 with high precision.

[0035] In addition, the compression spring 51 is used to press the second protrusion 41 against the wall 21b of the straight-advance groove 21 of the second fixed tube 20 via the first protrusion 31, thereby suppressing the slackness of the first lens holding frame F1 and the second lens holding frame F2 when they move, and enabling the first lens holding frame F1 and the second lens holding frame F2 to move with high precision in the straight-advance groove 21.

[0036] like Figure 4 (A) and Figure 4 As shown in (B), the first protrusion 31 and the second protrusion 41 at least partially overlap in the circumferential direction centered on the optical axis OA. More specifically, whether the first lens group L1 and the second lens group L2 are in the most separated state or in the most proximal state, the first protrusion 31 and the second protrusion 41 at least partially overlap in the circumferential direction centered on the optical axis OA. Thus, the first protrusion 31 and the second protrusion 41 can guide each other in the direction of the optical axis OA.

[0037] The second protrusion 41 of the second lens holding frame F2 has a bearing 411, which abuts against the wall 21b of one side of the straight groove 21 in the circumferential direction. The first protrusion 31 of the first lens holding frame F1 has a bearing 311, which abuts against the second protrusion 41. The block 50 has a bearing 501, which abuts against the wall 21a of the other side of the straight groove 21 in the circumferential direction. Figure 2 (A) and Figure 2 As shown in (B), plates 17 and 18 are mounted on the first protrusion 31 and the second protrusion 41 respectively so that the bearings 311, 411, and 501 do not separate when the lens barrel 100 is assembled. Figure 3 In the following figures, the plates 17 and 18 are omitted. In addition, the plates 17 and 18 may not be used. That is, the plates 17 and 18 may not exist between the bearings 311 , 411 , 501 and the linear groove 21 .

[0038] When the first lens retaining frame F1 is moved relative to the second lens retaining frame F2 and the second fixed cylinder 20 in the direction of the optical axis OA using the bearings 311 and 501, the sliding resistance between the first protrusion 31 and the second protrusion 41, and the sliding resistance between the block portion 50 and the wall 21a, can be reduced. Furthermore, when the second lens retaining frame F2 is moved relative to the first lens retaining frame F1 and the second fixed cylinder 20 in the direction of the optical axis OA using the bearings 311 and 411, the sliding resistance between the wall 21b and the second protrusion 41, and the sliding resistance between the first protrusion 31 and the second protrusion 41, can be reduced. The bearings 411 and 501 also reduce the sliding resistance when the first lens retaining frame F1 and the second lens retaining frame F2 are moved in the direction of the optical axis OA.

[0039] In addition, in this embodiment, the first protrusion 31, the second protrusion 41, and the block 50 are described as having the bearings 311, 411, and 501, respectively. However, at least one of the first protrusion 31, the second protrusion 41, and the block 50 only needs to have a bearing. For example, a protrusion may be provided instead of a bearing.

[0040] Next, a driving mechanism for driving the first lens holding frame F1 and the second lens holding frame F2 will be described. Figure 5 (A) is from Figure 1 A schematic perspective view of the second fixed cylinder 20 viewed from the direction indicated by arrow A12, Figure 5 (B) is an enlarged view of the first driving source unit. Figure 5 In (B), the second fixed cylinder 20 is omitted from illustration.

[0041] like Figure 5 As shown in (A), a first driving source unit 60 for moving the first lens holding frame F1 in the direction of the optical axis OA, and a second driving source unit 70 for moving the second lens holding frame F2 in the direction of the optical axis OA, which is different from the first driving source unit 60, are fixed to the outer periphery of the second fixed cylinder 20.

[0042] The first drive source unit 60 and the second drive source unit 70 are disposed between two linear grooves 21 arranged circumferentially around the optical axis OA, among the plurality (e.g., three) linear grooves 21 of the second fixed cylinder 20. Furthermore, the first drive source unit 60 and the second drive source unit 70 are disposed at positions opposing each other across the hole 22 of the second fixed cylinder 20. More specifically, the first drive source unit 60 and the second drive source unit 70 are disposed symmetrically with respect to the hole 22 in the circumferential direction around the optical axis OA.

[0043] Next, the configurations of the first drive source unit 60 and the second drive source unit 70 will be described.

[0044] like Figure 5 As shown in (B), the first drive source unit 60 includes a stepping motor 601, a screw rod 602, a frame 603, and a mounting member 604. The second drive source unit 70 includes a stepping motor 701, a screw rod 702, a frame 703, and a mounting member 704. Furthermore, the first drive source unit 60 and the second drive source unit 70 have the same configuration. Therefore, the configuration of the first drive source unit 60 will be described below, and a detailed description of the configuration of the second drive source unit 70 will be omitted.

[0045] The mounting member 604 is a U-shaped member having a first portion 604a to which the stepping motor 601 is fixed, a second portion 604b opposite to the first portion 604a, and a third portion 604c extending parallel to the screw rod 602 between the first portion 604a and the second portion 604b. A plurality of holes are formed in the third portion 604c. Figure 5 As shown in FIG. 1B , the first drive source unit 60 is fixed to the second fixed cylinder 20 by screwing the mounting member 604 onto the outer peripheral surface of the second fixed cylinder 20 using screws or the like. As a result, the peripheral wall of the second fixed cylinder 20 exists between the screw rod 602 and the first lens holding frame F1 in the radial direction of the second fixed cylinder 20. Furthermore, the screw rod 602 is disposed on the outer peripheral side relative to the third portion 604c.

[0046] The lead screw 602 is directly connected to the output shaft of the stepping motor 601 and extends in the direction of the optical axis OA. The front end of the lead screw 602 is rotatably supported by the second portion 604b of the mounting member 604. By rotatably supporting the front end of the lead screw 602 by the second portion 604b of the mounting member 604, vibration of the front end is suppressed.

[0047] The frame 603 is engaged with the screw rod 602. The frame 603 is held by the frame holding mechanism 33 of the first lens holding frame F1. In addition, the frame 703 of the second drive source unit 70 is held by the frame holding mechanism 43 of the second lens holding frame F2 (see FIG. 1 ). Figure 5 (A)).

[0048] Here, the rack 603 and the rack holding mechanism 33 will be described. The rack 703 and the rack holding mechanism 43 have the same configurations as the rack 603 and the rack holding mechanism 33, respectively.

[0049] Figure 6 (A) is an enlarged view of the rack 603 and the rack holding mechanism 33. Figure 6 (B) is from Figure 6(A) is a diagram showing the rack 603 and the rack holding mechanism 33 as viewed in the direction indicated by arrow A1. Figure 7 (A) is Figure 6 (B) AA line cross-sectional view, Figure 7 (B) is Figure 6 (B) BB line cross-sectional view, Figure 7 (C) is Figure 6 (B) CC line cross-sectional view. Figure 8 (A) is an enlarged view of the frame side of the shaft holding portion. Figure 8 (B) is a side view of the rack.

[0050] like Figure 6 As shown in FIG. 6A and the like, the frame 603 includes a frame body 611 and a biasing member 612 .

[0051] like Figure 8 As shown in FIG. 1B , the frame body 611 includes a first side wall portion 611a, a second side wall portion 611b opposing the first side wall portion 611a, and a connecting portion 611c connecting the first side wall portion 611a and the second side wall portion 611b. The connecting portion 611c has a through hole 611d formed therein, through which the first member 331a of the frame retaining shaft 331 is inserted.

[0052] The first side wall portion 611a, the second side wall portion 611b, and the connection portion 611c are formed of a single member. The chassis body 611 is made of a flexible resin such as polyacetal.

[0053] The first side wall portion 611a has two first contact portions 613a that contact the screw rod 602, and the second side wall portion 611b has a second contact portion 613b that contacts the screw rod 602. The first contact portion 613a and the second contact portion 613b are configured to clamp the screw rod 602. In addition, the first contact portion 613a and the second contact portion 613b are staggered. Threads having a shape complementary to the threads of the screw rod 602 are formed on the inner surfaces of the first contact portion 613a and the second contact portion 613b.

[0054] The urging member 6 is, for example, a leaf spring, one end of which is engaged with the first side wall portion 611a and the other end of which is engaged with the second side wall portion 611b. Figure 8As shown by the arrows in (B), the first side wall portion 611a and the second side wall portion 611b are forced inward with approximately the same force. As a result, since the first contact portion 613a and the second contact portion 613b are forced to approach each other, the threads formed on the inner surfaces of the first contact portion 613a and the second contact portion 613b are tightly coupled with the threads formed on the screw rod 602. As a result, the looseness between the screw rod 602 and the frame 603 is suppressed. In addition, as long as the first side wall portion 611a and the second side wall portion 611b can be forced inward with approximately the same force, a force member such as a torsion coil spring can also be used as the force member 612.

[0055] Next, the frame holding mechanism 33 will be described in detail.

[0056] The rack holding mechanism 33 is as follows Figure 6 (A)~ Figure 7 As shown in FIG. 1 (A), the frame holding shaft 331 , the shaft holding portion 332 , and the compression spring 333 are provided.

[0057] like Figure 3 As shown, the shaft holding portion 332 protrudes from the outer periphery of the first lens holding frame F1 in a direction intersecting the optical axis OA direction, and passes through the hole 22 provided in the second fixed cylinder 20 .

[0058] like Figure 7 As shown in FIG. 1A , the shaft holding portion 332 has a through hole 332 a through which the frame holding shaft 331 is inserted. The through hole 332 a is a stepped through hole. The through hole 332 a is located on the outer peripheral side of the outer peripheral surface of the second fixed cylinder 20 .

[0059] The shaft holding portion 332 is provided with a light shielding portion 334 that passes through a detection portion of a photointerrupter (not shown). This allows detection of the position of the first lens holding frame F1. The light shielding portion 334 is disposed on the outer peripheral side of the second fixed cylinder 20.

[0060] The frame retaining shaft 331 includes a first member 331a and a second member 331b. The first member 331a has a flange portion 331a1, which is inserted through the through-hole 611d of the frame body 611 and has one end inserted into the through-hole 332a of the shaft retaining portion 332. This retains the frame 603 between the flange portion 331a1 and the shaft retaining portion 332. The second member 331b is inserted into the shaft retaining portion 332 from the side opposite to the first member 331a and engages with the first member 331a. The through-hole 332a of the shaft retaining portion 332 is located on the outer peripheral side of the second fixed cylinder 20. Therefore, the frame 603 retained by the frame retaining shaft 331 inserted into the through-hole 332a is positioned outside the second fixed cylinder 20.

[0061] The first member 331a is arranged in the through hole 332a of the shaft holding portion 332 by a compression spring 333. Figure 7 Force is applied in the direction indicated by arrow A3 in (A). Consequently, the frame 603 is also forced in the direction indicated by arrow A3, pressing it against the shaft retaining portion 332. Because the frame 603 is not completely fixed to the shaft retaining portion 332, it can swing (rotate) about the axis of the frame retaining shaft 331. Therefore, compared to a case where the frame 603 is directly screwed into the shaft retaining portion 332, unnecessary force applied to the first lens retaining frame F1 is suppressed. This reduces the load on the stepping motor 601.

[0062] like Figure 8 As shown in (A), a spherical protrusion 332d is formed on the surface 332c of the shaft holding portion 332 that contacts the frame 603, and the protrusion 332d contacts the frame 603. In addition, the through hole 332a of the shaft holding portion 332 is as shown in FIG. Figure 7 (B) and Figure 7 As shown in (C), the first member 331a and the second member 331b are movable in the radial direction of the first lens retaining frame F1, as indicated by arrows A5 and A7, but are immovable in the circumferential direction, as indicated by arrows A6 and A8, centered on the optical axis OA. Specifically, while there is a gap between the side surfaces of the through-hole 332a and the first and second members 331a and 331b in the radial direction indicated by arrows A5 and A7, the through-hole 332a is formed so that the side surfaces of the through-hole 332a abut against the first and second members 331a and 331b in the circumferential direction indicated by arrows A6 and A8 (there is no gap). This eliminates circumferential slack and improves the circumferential tracking of the frame 603 relative to the lead screw 602.

[0063] The frame 603 is urged in the direction indicated by the arrow A3, and the side surface of the frame 603 contacts the spherical protrusion 332d. The frame holding shaft 331 is held by the shaft holding portion 332 so as to be movable in the radial direction of the first lens holding frame F1 centered on the optical axis OA. Figure 7 The frame 603 is swung in the manner indicated by arrow A4 in (A). Furthermore, as described above, the frame 603 is rotatable about the axis of the frame retaining shaft 331. While it is difficult to completely align the axial direction of the lead screw 602 with the direction of the optical axis OA, according to this embodiment, the above-described configuration allows the frame 603 to track the lead screw 602, thereby improving the accuracy of movement of the first lens retaining frame F1 in the direction of the optical axis OA.

[0064] In addition, the rack holding mechanisms 33 and 43 have substantially the same structure, and therefore, the detailed description of the rack holding mechanism 43 is omitted. Figure 3 As shown, the frame holding mechanism 43 includes a shaft holding portion 432 similar to the shaft holding portion 332 , a light shielding portion 434 similar to the light shielding portion 334 , and a through-hole 432 a similar to the through-hole 332 a .

[0065] As described in detail above, the lens barrel 100 of this embodiment includes: a first lens holding frame F1 having a first protrusion 31 that holds the first lens group L1; a stepping motor 601 that moves the first lens holding frame F1 in the direction of the optical axis OA; a second lens holding frame F2 having a second protrusion 41 that holds the second lens group L2; a stepping motor 701 that moves the second lens holding frame F2 in the direction of the optical axis OA; and a second fixed cylinder 20 that engages with the first protrusion 31 and the second protrusion 41, has a linear groove 21 extending in the direction of the optical axis OA, and is disposed on the outer side of the first and second lens holding frames F1 and F2. This restricts rotation of the first and second lens holding frames F1 and F2 about the optical axis OA, allowing linear movement of the first and second lens holding frames F1 and F2 in the direction of the optical axis OA. In addition, since the first protrusion 31 of the first lens holding frame F1 and the second protrusion 41 of the second lens holding frame F2 share a common straight groove 21, the second fixed tube 20 can be set to a simple structure. In addition, the first lens holding frame F1 and the second lens holding frame F2 can be moved with high precision in the optical axis direction.

[0066] Furthermore, according to this embodiment, the first protrusion 3 and the second protrusion 41 at least partially overlap in the circumferential direction centered on the optical axis OA. This allows the first protrusion 31 and the second protrusion 41 to guide each other in the direction of the optical axis OA within the linear groove 21. Furthermore, the length of the linear groove 21 in the direction of the optical axis OA can be shortened.

[0067] Furthermore, according to this embodiment, the first protrusion 31 and the second protrusion 41 are brought into contact with each other in the circumferential direction centered on the optical axis OA, and the second protrusion 41 is brought into contact with one wall 21b of the linear groove 21. The lens barrel 100 further includes a block portion 50 that is movable relative to the first protrusion 31 in the circumferential direction centered on the optical axis OA, and a compression spring 51 disposed between the first protrusion 31 and the block portion 50. The block portion 50 is brought into contact with the other wall 21a of the linear groove 21. This prevents the first lens retaining frame F1 and the second lens retaining frame F2 from loosening during independent movement. Furthermore, loosening between the first lens retaining frame F1 and the second lens retaining frame F2 can be prevented.

[0068] When tilting the camera in a guide-rod-type lens barrel, in which the lens retaining frame is guided linearly along the guide rod in the direction of the optical axis OA, a biasing member such as a spring is often used to bias the lens retaining frame against the guide rod, preventing any slack between the lens retaining frame and the guide rod. In this case, sliding resistance between the lens retaining frame and the guide rod increases, and the force exerted by the biasing member on the lens retaining frame requires a relatively large torque to move the lens retaining frame, making it difficult to drive the lens retaining frame using a small stepping motor. In contrast, in the lens barrel 100 of this embodiment, the block portion 50 and the compression spring 51 bias the first lens retaining frame F1 and the second lens retaining frame F2 against the walls 21a and 21b of the linear grooves 21, respectively, within the three linear grooves 21. This prevents excessive force from being applied to the first and second lens retaining frames F1 and F2. Consequently, even a small stepping motor with relatively low torque can drive the first and second lens retaining frames F1 and F2. Thereby, the 1st lens holding frame F1 and the 2nd lens holding frame F2 can be moved in the optical axis OA direction with high precision.

[0069] Furthermore, according to the present embodiment, the first protrusion 31, the second protrusion 41, and the block portion 50 each have a bearing, thereby reducing sliding resistance when the first lens holding frame F1 and the second lens holding frame F2 move.

[0070] Furthermore, according to this embodiment, the second fixed barrel 20 has a plurality of linear slots 21, and the stepping motor 601 and the stepping motor 701 are disposed between two linear slots 21 that are arranged circumferentially around the optical axis OA. This allows the stepping motors 601 and 701 to be positioned in a balanced manner. Furthermore, since the stepping motors 601 and 701 can be positioned in the space between the first fixed barrel 10 and the second fixed barrel 20, the lens barrel 100 can be miniaturized.

[0071] Furthermore, according to this embodiment, the lens barrel 100 includes a lead screw 602 rotated by a stepping motor 601, and a frame body 611 held by a first lens holding frame F1 and engaged with the lead screw 602. The frame body 61 includes a first side wall 611a, a second side wall 611b, and a connecting portion 611c connecting the first and second side walls 611a, 611b. The first and second side walls 611a, 611b, and the connecting portion 611c are formed from a single component. This reduces the number of components and, compared to a case where the frame body 611 is formed from multiple components, can reduce malfunctions.

[0072] Furthermore, the first side wall portion 611a has a first contact portion 613a that contacts the screw rod 602, and the second side wall portion 611b has a second contact portion 613b that contacts the screw rod 602. The lens barrel 100 includes a biasing member 612 that biases the frame body 611 so as to bring the first contact portion 613a and the second contact portion 613b closer together. As a result, the threads formed on the inner surfaces of the first contact portion 613a and the second contact portion 613b closely fit the threads formed on the screw rod 602, thereby suppressing loosening.

[0073] Furthermore, when a torsion spring or the like is used to bias one of the first side wall portion 611a or the second side wall portion 611b, causing the threads formed on the inner surface of the first contact portion 613a or the second contact portion 613b to tightly engage with the threads formed on the screw shaft 602, a reaction force to the force applied to the first side wall portion 611a or the second side wall portion 611b acts on the first lens retaining frame F1 via the frame body 611 and the frame holding shaft 331, affecting the first lens retaining frame F1, which is already being supported evenly by the three linear grooves 21. In this embodiment, the first and second contact portions 613a, 613b are biased toward the screw shaft 602 with substantially equal force, thereby preventing a reaction force from being generated on the frame body 611. Consequently, unnecessary force acting on the first lens retaining frame F1 can be suppressed. Consequently, the first lens retaining frame F1 can be evenly held within the second fixed cylinder 20. The same applies to the second lens holding frame F2.

[0074] As described in detail, the lens barrel 100 of this embodiment includes a stepping motor 601, a lead screw 602 rotated by the stepping motor 601, a first lens holding frame F1 engaged with the lead screw 602 and holding the first lens group L1, and a second fixed cylinder 20 disposed on the outer periphery of the first lens holding frame F1. The peripheral wall of the second fixed cylinder 20 exists between the lead screw 602 and the first lens holding frame F1. The presence of the peripheral wall of the second fixed cylinder 20 between the first lens holding frame F1 and the lead screw 602 prevents lubricant applied to the lead screw 602 or debris generated by sliding between the lead screw 602 and the frame 603 from adhering to the first lens group L1 and the second lens group L2, compared to a case where the lead screw 602 is disposed between the second fixed cylinder 20 and the first lens holding frame F1 (a case where the lead screw 602 is disposed on the inner periphery of the second fixed cylinder 20).

[0075] Furthermore, according to this embodiment, the lens barrel 100 includes a mounting member 604 that secures the stepping motor 601 to the second fixed barrel 20, and the screw rod 602 is positioned on the outer side relative to the third portion 604c of the mounting member 604. Furthermore, according to this embodiment, the frame 603 is positioned on the outer side relative to the third portion 604c of the mounting member 604. Furthermore, the frame 603 is positioned on the outer side relative to the second fixed barrel 20. Thus, since the components of the first drive source unit 60 that drives the first lens retaining frame F1 are positioned on the outer side of the second fixed barrel 20, that is, the second fixed barrel 20 can be interposed between the first drive source unit 60 and the first lens retaining frame F1, the second fixed barrel 20 can be used to prevent debris from adhering to the first lens group L1 and the second lens group L2. The same applies to the second drive source unit 70.

[0076] Furthermore, according to this embodiment, the second fixed barrel 20 has a hole 22 for arranging the frame 603 on the outer peripheral side of the second fixed barrel 20. Since it is not necessary to form any holes other than the hole 22 in the partial wall surfaces of the first lens holding frame F1 and the second lens holding frame F2 that house the second fixed barrel 20, light leakage can be suppressed.

[0077] Furthermore, according to this embodiment, the first lens holding frame F1 includes a light-shielding portion 334 that is detected by a photointerrupter (not shown) that detects the position of the first lens holding frame F1. The light-shielding portion 334 is disposed on the outer peripheral side of the second fixed cylinder 20. Thus, since the second fixed cylinder 20 can block light from the light-emitting portion of the photointerrupter, the effect of the light from the photointerrupter on imaging can be reduced.

[0078] In the above embodiment, at least a portion of the stepping motor 601 only needs to be disposed on the outer circumference side of the second fixed cylinder 20 . In other words, a portion of the stepping motor 601 may be disposed on the inner circumference side of the second fixed cylinder 20 .

[0079] In the above embodiment, the second fixed cylinder 20 that houses the first lens holding frame F1 and the second lens holding frame F2 may be a movable cylinder that can move linearly in the direction of the optical axis OA. In the above embodiment, the lens barrel 100 may be a single-focus lens or a zoom lens.

[0080] Furthermore, the first drive source unit 60 and the second drive source unit 70 of the above embodiment can be applied to a guide bar type lens barrel that moves the first lens holding frame F1 and the second lens holding frame F2 linearly in the optical axis OA direction along the guide bar.

[0081] Alternatively, the lens barrel 100 may include only one of the first lens holding frame F1 and the second lens holding frame F2. Specifically, from the perspective of preventing the intrusion of debris, the configuration in which the peripheral wall of the second fixed cylinder 20 is provided between the lens holding frame and the lead screw can be applied to both the case where there are multiple lens groups and the case where there is only one lens group.

[0082] Furthermore, in the above-described embodiment, at least one of the bearings 311 of the first protrusion 31 and the bearings 411 of the second protrusion 41 may have a different diameter from the other bearings 311 and 411. For example, one of the two bearings 311 may have a different diameter from the other bearing 311. Alternatively, one of the two bearings 411 may have a different diameter from the other bearing 411. Alternatively, one of the two bearings 311 may have a different diameter from one or both of the two bearings 411. Furthermore, both bearings 311 and both bearings 411 may have different diameters. By changing the diameters of the bearings 311 and 411 in this manner, the tilt adjustment or alignment of the first lens retaining frame F1 and the second lens retaining frame F2 can be performed.

[0083] Furthermore, in the above embodiment, the compression spring 51 is provided between the first protrusion 31 and the block 50, but the present invention is not limited thereto. Figure 9 (A)~ Figure 11 (B) describes an example of arrangement of the first protrusion 31 and the second protrusion 41 according to a modified example.

[0084] (Variation 1)

[0085] Figure 9 (A) is a diagram showing an example of arrangement of the first protrusion 31A and the second protrusion 41A according to Modification 1. Figure 9 (B) is in Figure 9 (A) is a diagram showing a state where bearings 311 and 411 are removed.

[0086] like Figure 9 As shown in FIG. 1A , in Modification 1, the first protrusion 31A includes a bearing 311 that contacts one wall 21 a of the linear groove 21 . Furthermore, the second protrusion 41A includes a bearing 411 that contacts the other wall 21 b of the linear groove 21 .

[0087] Two pressing members 81 are provided between the first protrusion 31A and the second protrusion 41A. Figure 9As shown in (B), one end of the pressing member 81 engages with the protrusion 412 of the second protrusion 41A, and the other end of the pressing member 81 partially contacts the protrusion 312 of the first protrusion 31A. The two pressing members 81 are connected together by a tension spring 82. When the pressing members 81 are pulled toward each other by the tension spring 82, the protrusion 312 and the protrusion 412 are pressed in a direction that separates the first protrusion 31A and the second protrusion 41A from each other along the inclined surface 81a formed at the other end of the pressing member 81. As a result, since the first protrusion 31A and the second protrusion 41A are pressed against the wall 21b and the wall 21a, respectively, the first lens holding frame F1 and the second lens holding frame F2 are suppressed from loosening when they move straight along the straight groove 21 in the direction of the optical axis OA.

[0088] (Variation 2)

[0089] Figure 10 2 is a diagram illustrating an example arrangement of the first protrusion 31B and the second protrusion 41B of Modification 2. In Modification 2, a first block 85 having a bearing 851 and a second block 86 having a bearing 861 are provided between the first protrusion 31B and the second protrusion 41B. A compression spring 87 is provided between the first block 85 and the second block 86. The compression spring 87 applies a force to the first block 85 and the second block 86 in a direction separating the first block 85 and the second block 86, as indicated by arrow A21. As a result, the first block 85 and the second block 86 respectively push up the inclined surfaces 313a and 313b formed on the first protrusion 31B, and also push up the inclined surfaces 413a and 413b formed on the second protrusion 41B. As a result, the first protrusion 31B and the second protrusion 41B are forced in the direction of separation from each other and pressed against the wall 21a and the wall 21b respectively, thereby suppressing the loosening of the first lens holding frame F1 and the second lens holding frame F2 when they move straight along the straight groove 21 in the direction of the optical axis OA.

[0090] (Variation 3)

[0091] Figure 11 (A) is a diagram showing an example of arrangement of the first protrusion 31C and the second protrusion 41C of Modification 3. Figure 11 (B) is Figure 11 (A) DD line cross-sectional view. Figure 11As shown in (A), in Modification 3, the linear groove 21 of the second fixed cylinder 20 includes a protrusion 211, and the first protrusion 31C and the second protrusion 41C are connected together by a tension spring 88. The first protrusion 31C has a bearing 311 that abuts against the side wall 211a of one side of the protrusion 211. The second protrusion 41C also has a bearing 411 that abuts against the side wall 211b of the other side of the protrusion 211. The tension spring 88 urges the first protrusion 31C and the second protrusion 41C toward each other. As a result, the first protrusion 31C is pressed against the side wall 211a, and the second protrusion 41C is pressed against the side wall 211b, thereby suppressing the first lens retaining frame F1 and the second lens retaining frame F2 from loosening during their linear movement along the linear groove 21 in the direction of the optical axis OA.

[0092] In addition, the structure of the rack 603 is not limited to the above-mentioned embodiment. Figure 12 (A) and Figure 12 (B) is a diagram showing a modified example of the rack 603A. Figure 12 As shown in (A), the rack body 611a of the rack 603A includes a first side wall portion 611a, a second side wall portion 611b, and a connecting portion 611c connecting the first side wall portion 611a and the second side wall portion 611b, and the first side wall portion 611a, the second side wall portion 611b, and the connecting portion 611c are composed of one component.

[0093] In the modified example, the end of the first contact portion 613a of the first side wall portion 611a and the end of the second contact portion 613b of the second side wall portion 611b are connected together by a tension spring 612A. Figure 12 In (B), as indicated by arrow A22, forces are applied in a direction oblique to the direction in which they approach each other. Consequently, the threads formed on the inner side of the first contact portion 613a and the threads formed on the inner side of the second contact portion 613b closely mate with the threads of the screw shaft 602, thereby suppressing loosening. Furthermore, the first contact portion 613a and the second contact portion 613b are applied toward the screw shaft 602 with approximately the same force, thereby preventing a reaction force from being generated on the frame body 611a. Consequently, unnecessary forces acting on the first lens retaining frame F1 can be suppressed. Consequently, the first lens retaining frame F1 can be evenly retained within the second fixed cylinder 20.

[0094] The above-mentioned embodiments are preferred embodiments. However, they are not limited thereto and various modifications can be implemented without departing from the main purpose, and any constituent elements can be combined. In addition, the disclosures of the publications cited in the descriptions thus far are incorporated as part of the description of this specification.

[0095] Description of Reference Numerals

[0096] 1 Camera

[0097] 101st fixed cylinder

[0098] 20 2nd fixed cylinder

[0099] 21 straight slot

[0100] Wall 21a, 21b

[0101] 22 holes

[0102] 31 No. 1 protrusion

[0103] 41 2nd protrusion

[0104] 50 pieces

[0105] 51 compression spring

[0106] 60 1st driving source unit

[0107] 70 Second drive source unit

[0108] 100 lens barrel

[0109] 311, 411, 501 bearings

[0110] 601, 701 stepper motors

[0111] 602, 702 screw

[0112] 603, 703 racks

[0113] 611 rack body

[0114] 611a 1st side wall portion

[0115] 611b Second side wall portion

[0116] 611c connection

[0117] 612 force-applying component

[0118] 612a tension spring

[0119] 613a 1st contact part

[0120] 613b Second contact portion

[0121] F1 first lens holding frame

[0122] F2 second lens holding frame

[0123] L1 1st lens group

[0124] L2: Second lens group.

Claims

1. A lens barrel comprising: a first lens holding frame that holds the first lens and has a first protrusion; a first motor for moving the first lens holding frame in the direction of the optical axis; a second lens holding frame that holds the second lens and has a second protrusion; a second motor for moving the second lens holding frame in the optical axis direction; and an outer cylinder having a linear groove engaging with the first protrusion and the second protrusion and extending in the optical axis direction and arranged on the outer peripheral side relative to the first lens holding frame and the second lens holding frame, The first protrusion and the second protrusion at least partially overlap in a circumferential direction centered on the optical axis and abut against each other in the circumferential direction.

2. The lens barrel according to claim 1, wherein: The second protrusion abuts against one wall of the linear groove.

3. The lens barrel according to claim 2, comprising: a block portion movable relative to the first protrusion in a circumferential direction centered on the optical axis; and A biasing portion is disposed between the first protrusion and the block portion.

4. The lens barrel according to claim 3, wherein: The block portion abuts against the other wall of the linear groove.

5. The lens barrel according to claim 3 or 4, wherein: At least one of the first protrusion, the second protrusion, and the block portion includes a bearing.

6. The lens barrel according to claim 5, wherein: The first protrusion and the second protrusion each have a bearing. At least one of the bearings has a different diameter than the other bearings.

7. The lens barrel according to any one of claims 1 to 6, wherein The outer cylinder has a plurality of straight grooves. The first motor and the second motor are arranged between a first linear groove and a second linear groove, among the plurality of linear grooves, which are arranged side by side in a circumferential direction around the optical axis.

8. The lens barrel according to any one of claims 1 to 7, wherein The first lens and the second lens are focusing lenses.

9. The lens barrel according to any one of claims 1 to 8, comprising: a rotating shaft rotated by the first motor; and an engaging portion held by the first lens holding frame and engaged with the rotation axis, The engaging portion includes a first side wall portion, a second side wall portion, and a connecting portion connecting the first side wall portion and the second side wall portion. The first side wall portion, the second side wall portion, and the connecting portion are formed of a single member.

10. The lens barrel according to claim 9, wherein: The first side wall portion has a first contact portion that contacts the rotation shaft. The second side wall portion has a second contact portion that contacts the rotation shaft. The lens barrel includes an urging portion that urges the engaging portion so as to bring the first contact portion and the second contact portion closer together. 11 . An imaging device comprising the lens barrel according to claim 1 .

Images