JP7505280B2 - Lens barrel and imaging device - Google Patents

Description

Related to lens barrels and imaging devices.

Lens barrels have been proposed in which multiple lens groups are driven separately by independent actuators (for example, see Patent Document 1). There is also a demand for moving multiple lens groups with high precision.

JP 2019-32565 A

According to a first aspect, a lens barrel includes a first drive source, a second drive source, a first rotation shaft rotated by the first drive source, a second rotation shaft rotated by the second drive source, a first lens retaining frame having a first engagement portion that engages with the first rotation shaft and holds a first lens, a second lens retaining frame having a second engagement portion that engages with the second rotation shaft and holds a second lens, and an outer cylinder that is disposed on an outer circumferential side of the first lens retaining frame and the second lens retaining frame , wherein the first lens retaining frame is moved in the optical axis direction by the drive force of the first drive source, the second lens retaining frame is moved in the optical axis direction by the drive force of the second drive source, and a distance between the first rotation shaft and the first lens retaining frame is increased. a peripheral wall of the outer tube is located between the second rotation axis and the second lens retaining frame, the first lens retaining frame has a first axis retaining portion that holds the first engagement portion, the second lens retaining frame has a second axis retaining portion that holds the second engagement portion, the first engagement portion is rotatable around the first axis retaining portion and the second engagement portion is rotatable around the second axis retaining portion, the outer tube has holes for positioning the first engagement portion and the second engagement portion outer circumferentially of the outer tube, and the first driving source, the second driving source, and the holes are positioned in a range where the distance between the first rotation axis and the second rotation axis is shorter in the circumferential direction of a circle centered on the optical axis .

According to a second aspect, an imaging device includes the lens barrel.

The configuration of the embodiments described below may be modified as appropriate, and at least a portion of the configuration may be replaced with other components. Furthermore, components that are not specifically limited in their placement may be placed in any position that achieves their function, not limited to the placement disclosed in the embodiments.

FIG. 1 is a cross-sectional view of a lens barrel according to an embodiment. Figure 2(A) is a partial cross-sectional oblique view showing the relationship between the second fixed barrel, the first lens retaining frame, and the second lens retaining frame, and Figure 2(B) is a partial cross-sectional view of the second fixed barrel when viewed from the direction indicated by arrow A10 in Figure 2(A). FIG. 3 is a cross-sectional view taken along line AA in FIG. 4A and 4B are cross-sectional views taken along line BB in FIG. 5A is a schematic perspective view of the second fixed barrel as viewed from the direction indicated by the arrow A12 in FIG. 1, and FIG. 5B is an enlarged view of the first drive source unit. 6A is an enlarged view of the rack holding mechanism, and FIG. 6B is a view of the rack holding mechanism as viewed from the direction indicated by the arrow A1 in FIG. 6A. 7(A) is a cross-sectional view taken along line AA in FIG. 6(B), FIG. 7(B) is a cross-sectional view taken along line BB in FIG. 6(B), and FIG. 7(C) is a cross-sectional view taken along line CC in FIG. 6(B). FIG. 8A is an enlarged view of the rack-side surface of the shaft holder, and FIG. 8B is a side view of the rack. 9A and 9B are diagrams showing an example of the arrangement of the first protrusions and the second protrusions in the rectilinear grooves according to the first modification. FIG. 10 is a diagram showing an example of the arrangement of the first protrusions and the second protrusions in the rectilinear grooves according to the second modification. 11A and 11B are diagrams showing an example of the arrangement of the first protrusions and the second protrusions in the rectilinear grooves according to the third modification. 12A and 12B are diagrams for explaining a rack according to a modified example.

The embodiment will be described below with reference to the drawings. FIG. 1 is a diagram showing a camera 1 equipped with a lens barrel 100 according to this embodiment and a camera body 101. FIG. 2(A) is a partial cross-sectional perspective view showing the relationship between a second fixed barrel 20, a first lens holding frame F1, and a second lens holding frame F2, which will be described later, and FIG. 2(B) is a partial cross-sectional view of the second fixed barrel 20 as viewed from the direction indicated by arrow A10 in FIG. 2(A). Also, FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2(B).

In this embodiment, the lens barrel 100 is detachable from the camera body 101, but this is not limited thereto, and the lens barrel 100 and the camera body 101 may be integrated.

As shown in FIG. 1, the lens barrel 100 according to this embodiment includes a first fixed barrel 10, a second fixed barrel 20 arranged on the inner periphery side of the first fixed barrel 10, and a focus ring 15 arranged on the outer periphery side of the first fixed barrel 10. In this embodiment, the first fixed barrel 10 is composed of multiple parts, but it may be composed of a single part. As shown in FIG. 1, a lens mount 13 is fixed to the first fixed barrel 10, which enables the lens barrel 100 to be attached and detached to a camera body 101.

The lens barrel 100 also includes a plurality of lens groups, including a first lens group L1 and a second lens group L2, which are sequentially arranged along a common optical axis OA. The first lens group L1 and the second lens group L2 are each a focus lens group.

The first lens group L1 is held in the first lens holding frame F1, the second lens group L2 is held in the second lens holding frame F2, and the other lens groups are held in the first fixed barrel 10.

Although details will be described 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. The first drive source unit 60 or the second drive source unit 70 may be, for example, a stepping motor, a voice coil motor, an ultrasonic motor, or the like. As a result, for example, the first lens holding frame F1 and the second lens holding frame F2 move linearly in the direction of the optical axis OA, either individually or together, in response to the operation of the focus ring 15.

The first lens holding frame F1 and the second lens holding frame F2 are disposed inside the second fixed barrel 20, as shown in FIG. 2(A). As shown in FIG. 1 and FIG. 2(A), the second fixed barrel 20 has multiple (three in this embodiment) linear grooves 21 extending in the optical axis OA direction, and a hole 22 penetrating the second fixed barrel 20 and extending in the optical axis OA direction.

In this embodiment, the wall of the portion of the second fixed barrel 20 that houses the first lens holding frame F1 and the second lens holding frame F2 does not have any openings that penetrate the wall (connecting the inside and outside of the wall) other than the hole 22. This makes it possible to suppress light leakage from the outside to the inside of the second fixed barrel 20 and also makes it easy to take measures against light leakage. The strength of the second fixed barrel 20 is also improved.

As shown in FIG. 3, the first lens holding frame F1 has a first protrusion 31 that protrudes in a direction intersecting the optical axis OA direction, and the second lens holding frame F2 has a second protrusion 41 that protrudes in a direction intersecting the optical axis OA direction. The first protrusion 31 and the second protrusion 41 engage with the linear groove 21 of the second fixed barrel 20. More specifically, the first protrusion 31 and the second protrusion 41 abut against each other, and the first protrusion 31 and the second protrusion 41 engage with the linear groove 21 in the abutting state.

Between the first protrusion 31 and the wall 21a of the linear groove 21, a block 50 is provided that abuts against the wall 21a. The block 50 moves together with the first lens holding frame F1 (first protrusion 31) in the optical axis OA direction, but is assembled to the first lens holding frame F1 so as to be movable relative to the first protrusion 31 in the circumferential direction around the optical axis OA. Since the first protrusion 31, the second protrusion 41, and the block 50 engage with the linear groove 21, the rotation of the first lens holding frame F1 and the second lens holding frame F2 around the optical axis OA is restricted, and the first lens holding frame F1 and the second lens holding frame F2 are guided by the linear groove 21 and move linearly in the optical axis OA direction.

The relationship between the second fixed barrel 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 50 will now be described with reference to Figures 4(A) and 4(B).

Figures 4(A) and 4(B) are cross-sectional views taken along line B-B in Figure 3, with Figure 4(A) showing the state in which the first lens group L1 and the second lens group L2 are furthest apart in the direction of the optical axis OA, and Figure 4(B) showing the state in which the first lens group L1 and the second lens group L2 are closest in the direction of the optical axis OA. In Figures 4(A) and 4(B), the main body of the first lens holding frame F1 and the main body of the second lens holding frame F2 are not shown.

As shown in FIG. 4(A) and FIG. 4(B), a compression spring 51 is provided between the first protrusion 31 and the block 50 to bias the first protrusion 31 and the block 50 in a direction in which the first protrusion 31 and the block 50 move away from each other. Note that the compression spring 51 may be another biasing member, such as a leaf spring.

The compression spring 51 presses the block 50 against the wall 21a of the linear groove 21, and urges the first protrusion 31 against the second protrusion 41. This makes it possible to suppress rattling when the first lens holding frame F1 and the second lens holding frame F2 move independently (reducing rattling between the first lens holding frame F1 and the second lens holding frame F2), and allows the first lens holding frame F1 and the second lens holding frame F2 to move precisely within the linear groove 21.

In addition, the compression spring 51 presses the second protrusion 41 against the wall 21b of the linear groove 21 of the second fixed barrel 20 via the first protrusion 31, suppressing rattling when the first lens holding frame F1 and the second lens holding frame F2 move, allowing the first lens holding frame F1 and the second lens holding frame F2 to move with precision within the linear groove 21.

As shown in Figures 4(A) and 4(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 distant state or in the closest state, the first protrusion 31 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.

The second protrusion 41 of the second lens holding frame F2 has a bearing 411 and abuts against one wall 21b of the straight groove 21 in the circumferential direction. The first protrusion 31 of the first lens holding frame F1 has a bearing 311 and abuts against the second protrusion 41. The block 50 has a bearing 501 and abuts against the other wall 21a of the straight groove 21 in the circumferential direction. As shown in FIG. 2(A) and FIG. 2(B), plates 17 and 18 are attached to the first protrusion 31 and the second protrusion 41, respectively, so that the bearings 311, 411, and 501 do not come off when the lens barrel 100 is assembled, but the plates 17 and 18 are omitted from the figures from FIG. 3 onwards. The plates 17 and 18 do not have to be used. In other words, the plates 17 and 18 do not have to be present between the bearings 311, 411, and 501 and the straight groove 21.

The bearings 311 and 501 can reduce the sliding resistance between the first protrusion 31 and the second protrusion 41 and between the block 50 and the wall 21a when the first lens holding frame F1 moves in the optical axis OA direction relative to the second lens holding frame F2 and the second fixed barrel 20. In addition, the bearings 311 and 411 can reduce the sliding resistance between the wall 21b and the second protrusion 41 and between the first protrusion 31 and the second protrusion 41 when the second lens holding frame F2 moves in the optical axis OA direction relative to the first lens holding frame F1 and the second fixed barrel 20. In addition, the bearings 411 and 501 can reduce the sliding resistance when the first lens holding frame F1 and the second lens holding frame F2 move in the optical axis OA direction.

In this embodiment, the first protrusion 31, the second protrusion 41, and the block 50 are described as having bearings 311, 411, and 501, respectively, but it is sufficient that at least one of the first protrusion 31, the second protrusion 41, and the block 50 has a bearing. For example, a protrusion may be provided instead of a bearing.

Next, the drive mechanism for driving the first lens holding frame F1 and the second lens holding frame F2 will be described. Fig. 5(A) is a schematic perspective view of the second fixed barrel 20 as viewed from the direction indicated by the arrow A12 in Fig. 1, and Fig. 5(B) is an enlarged view of the first drive source unit. Note that Fig. 5(B) omits the illustration of the second fixed barrel 20.

As shown in FIG. 5(A), a first drive source unit 60 for moving the first lens holding frame F1 in the direction of the optical axis OA, and a second drive source unit 70 different from the first drive source unit 60 for moving the second lens holding frame F2 in the direction of the optical axis OA are fixed to the outer periphery of the second fixed barrel 20.

The first drive source unit 60 and the second drive source unit 70 are provided between two of the multiple (e.g., three) linear grooves 21 that the second fixed barrel 20 has, which are arranged side by side in the circumferential direction centered on the optical axis OA. Furthermore, the first drive source unit 60 and the second drive source unit 70 are provided in opposing positions across a hole 22 that the second fixed barrel 20 has. More specifically, the first drive source unit 60 and the second drive source unit 70 are arranged symmetrically with respect to the hole 22 in the circumferential direction centered on the optical axis OA.

Next, the configuration of the first drive source unit 60 and the second drive source unit 70 will be described.

As shown in FIG. 5B, the first drive source unit 60 includes a stepping motor 601, a lead screw 602, a rack 603, and a mounting member 604. The second drive source unit 70 includes a stepping motor 701, a lead screw 702, a rack 703, and a mounting member 704. Since the first drive source unit 60 and the second drive source unit 70 have the same configuration, the following describes the configuration of the first drive source unit 60, and a detailed description of the configuration of the second drive source unit 70 is omitted.

The mounting member 604 is a U-shaped member, and has a first part 604a to which the stepping motor 601 is fixed, a second part 604b facing the first part 604a, and a third part 604c extending parallel to the lead screw 602 between the first part 604a and the second part 604b. A plurality of holes are formed in the third part 604c, and as shown in FIG. 5B, the first drive source unit 60 is fixed to the second fixed barrel 20 by screwing the mounting member 604 to the outer circumferential surface of the second fixed barrel 20 with a screw or the like. As a result, in the radial direction of the second fixed barrel 20, the peripheral wall of the second fixed barrel 20 exists between the lead screw 602 and the first lens holding frame F1. Also, the lead screw 602 is arranged on the outer circumferential side of the third part 604c.

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 tip of the lead screw 602 is rotatably supported by the second part 604b of the mounting member 604. The tip of the lead screw 602 is rotatably supported by the second part 604b of the mounting member 604, thereby suppressing vibration of the tip.

A rack 603 is engaged with the lead screw 602. The rack 603 is held by a rack holding mechanism 33 provided in the first lens holding frame F1. The rack 703 of the second drive source unit 70 is held by a rack holding mechanism 43 provided in the second lens holding frame F2 (see FIG. 5A).

Here, we will explain the rack 603 and the rack holding mechanism 33. Note that the rack 703 and the rack holding mechanism 43 have the same configuration as the rack 603 and the rack holding mechanism 33, respectively.

Figure 6(A) is an enlarged view of the rack 603 and the rack holding mechanism 33, and Figure 6(B) is a view of the rack 603 and the rack holding mechanism 33 as viewed from the direction indicated by the arrow A1 in Figure 6(A). Figure 7(A) is a cross-sectional view taken along line A-A in Figure 6(B), Figure 7(B) is a cross-sectional view taken along line B-B in Figure 6(B), and Figure 7(C) is a cross-sectional view taken along line C-C in Figure 6(B). Figure 8(A) is an enlarged view of the rack-side surface of the shaft holding portion, and Figure 8(B) is a side view of the rack.

As shown in FIG. 6(A) etc., the rack 603 includes a rack body 611 and a biasing member 612.

As shown in FIG. 8B, the rack body 611 has a first side wall portion 611a, a second side wall portion 611b facing the first side wall portion 611a, and a connection portion 611c connecting the first side wall portion 611a and the second side wall portion 611b. A through hole 611d is formed in the connection portion 611c, through which the first member 331a of the rack holding shaft 331 is inserted.

The first side wall portion 611a, the second side wall portion 611b, and the connection portion 611c are configured from a single member. The rack body 611 is made of a flexible resin, such as polyacetal.

The first side wall portion 611a has two first contact portions 613a that contact the lead screw 602, and the second side wall portion 611b has one second contact portion 613b that contacts the lead screw 602. The first contact portion 613a and the second contact portion 613b are configured to sandwich the lead screw 602. The first contact portion 613a and the second contact portion 613b are arranged alternately. The inner surfaces of the first contact portion 613a and the second contact portion 613b are formed with threads that are complementary to the threads of the lead screw 602.

The biasing member 612 is, for example, a leaf spring, one end of which engages with the first side wall portion 611a and the other end of which engages with the second side wall portion 611b, and biases the first side wall portion 611a and the second side wall portion 611b inward with approximately the same force as shown by the arrow in FIG. 8 (B). As a result, the first contact portion 613a and the second contact portion 613b are biased to approach each other, so that the threads formed on the inner surfaces of the first contact portion 613a and the second contact portion 613b are in close contact with the threads formed on the lead screw 602. This suppresses rattle between the lead screw 602 and the rack 603. Note that, as long as the first side wall portion 611a and the second side wall portion 611b can be biased inward with approximately the same force, a biasing member such as a torsion coil spring may be used as the biasing member 612.

Next, the rack holding mechanism 33 will be described in detail.

As shown in Figures 6(A) to 7(A), the rack holding mechanism 33 includes a rack holding shaft 331, a shaft holding portion 332, and a compression spring 333.

As shown in FIG. 3, the shaft holder 332 protrudes from the outer periphery of the first lens holder frame F1 in a direction intersecting the optical axis OA and passes through the hole 22 of the second fixed barrel 20.

As shown in FIG. 7A, the shaft holding portion 332 has a through hole 332a through which the rack holding shaft 331 is inserted. The through hole 332a is a stepped through hole. The through hole 332a is located on the outer periphery side of the outer periphery of the second fixed barrel 20.

The shaft holder 332 is also provided with a light-shielding section 334 that passes between the detectors of a photointerrupter (not shown). This allows the position of the first lens holder frame F1 to be detected. The light-shielding section 334 is located on the outer periphery side of the second fixed barrel 20.

The rack holding shaft 331 has a first member 331a and a second member 331b. The first member 331a has a flange portion 331a1, and is inserted into the through hole 611d of the rack body 611, and one end is inserted into the through hole 332a of the shaft holding part 332 to hold the rack 603 between the flange portion 331a1 and the shaft holding part 332. The second member 331b is inserted into the shaft holding part 332 from the opposite side to the first member 331a, and is connected to the first member 331a. Since the through hole 332a of the shaft holding part 332 is located on the outer periphery side of the outer periphery of the second fixed barrel 20, the rack 603 held by the rack holding shaft 331 inserted into the through hole 332a is positioned outside the second fixed barrel 20.

The first member 331a is biased in the direction indicated by the arrow A3 in FIG. 7A by a compression spring 333 disposed in the through hole 332a of the shaft holder 332. As a result, the rack 603 is also biased in the direction indicated by the arrow A3 and pressed against the shaft holder 332. Since the rack 603 is not completely fixed to the shaft holder 332, the rack 603 can oscillate (rotate) around the axis of the rack holder shaft 331. Therefore, compared to when the rack 603 is directly screwed to the shaft holder 332, the application of unnecessary force to the first lens holder frame F1 is suppressed. This reduces the load on the stepping motor 601.

As shown in Fig. 8(A), a spherical protrusion 332d is formed on the surface 332c of the shaft holding part 332 that abuts against the rack 603, and the protrusion 332d abuts against the rack 603. Also, as shown in Fig. 7(B) and Fig. 7(C), the through hole 332a of the shaft holding part 332 is formed so that the first member 331a and the second member 331b can move in the radial direction of the first lens holding frame F1 as indicated by arrows A5 and A7, but cannot move in the circumferential direction around the optical axis OA as indicated by arrows A6 and A8. That is, in the radial direction indicated by arrows A5 and A7, there is a gap between the side of the through hole 332a and the first and second members 331a and 331b, but in the circumferential direction indicated by arrows A6 and A8, the through hole 332a is formed so that the side of the through hole 332a abuts the first and second members 331a and 331b (no gaps). This eliminates backlash in the circumferential direction, improving the ability of the rack 603 to follow the lead screw 602 in the circumferential direction.

The rack 603 is biased in the direction indicated by the arrow A3, and the side of the rack 603 abuts against the spherical protrusion 332d. Furthermore, the rack 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. This allows the rack 603 to swing as indicated by the arrow A4 in FIG. 7A. Furthermore, as described above, the rack 603 is rotatable around the axis of the rack holding shaft 331. Although it is difficult to completely align the axial direction of the lead screw 602 with the optical axis OA direction, according to this embodiment, the above configuration allows the rack 603 to follow the lead screw 602, improving the movement accuracy of the first lens holding frame F1 in the optical axis OA direction.

Since the rack holding mechanisms 33 and 43 have almost the same configuration, detailed description of the rack holding mechanism 43 will be omitted. Specifically, as shown in FIG. 3, the rack holding mechanism 43 includes an axis holding portion 432 similar to the axis holding portion 332, a light shielding portion 434 similar to the light shielding portion 334, and a through hole 432a similar to the through hole 332a.

As described above in detail, the lens barrel 100 according to this embodiment includes a first lens holding frame F1 that holds a first lens group L1 and has a first protrusion 31, a stepping motor 601 that moves the first lens holding frame F1 in the optical axis OA direction, a second lens holding frame F2 that holds a second lens group L2 and has a second protrusion 41, a stepping motor 701 that moves the second lens holding frame F2 in the optical axis OA direction, and a second fixed cylinder 20 that engages with the first protrusion 31 and the second protrusion 41, has a linear groove 21 that extends in the optical axis OA direction, and is disposed on the outer periphery side of the first lens holding frame F1 and the second lens holding frame F2. This restricts the rotation of the first lens holding frame F1 and the second lens holding frame F2 around the optical axis OA, and allows the first lens holding frame F1 and the second lens holding frame F2 to move linearly in the optical axis OA direction. In addition, because the first protrusion 31 of the first lens holding frame F1 and the second protrusion 41 of the second lens holding frame F2 share one straight groove 21, the second fixed barrel 20 can be configured simply, and the first lens holding frame F1 and the second lens holding frame F2 can be moved in the optical axis direction with high precision.

In addition, according to this embodiment, the first protrusion 31 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 optical axis OA direction within the linear groove 21. In addition, the length of the linear groove 21 in the optical axis OA direction can be shortened.

In addition, according to this embodiment, the first protrusion 31 and the second protrusion 41 abut in the circumferential direction centered on the optical axis OA, and the second protrusion 41 abuts against one wall 21b of the linear groove 21. Furthermore, the lens barrel 100 includes a block 50 that is movable in the circumferential direction centered on the optical axis OA relative to the first protrusion 31, and a compression spring 51 disposed between the first protrusion 31 and the block 50, and the block 50 abuts against the other wall 21a of the linear groove 21. This makes it possible to suppress rattling when the first lens holding frame F1 and the second lens holding frame F2 move independently. Also, rattling between the first lens holding frame F1 and the second lens holding frame F2 can be suppressed.

In a guide bar type lens barrel in which the lens holding frame is guided in the direction of the optical axis OA along the guide bar, the lens holding frame is often biased against the guide bar by a biasing member such as a spring so that there is no rattle between the lens holding frame and the guide bar when the camera is tilted. In this case, the sliding resistance between the lens holding frame and the guide bar increases, and the force of the biasing member is applied to the lens holding frame, so that a relatively large torque is required to move the lens holding frame, and it may be difficult to drive the lens holding frame with a small stepping motor. On the other hand, in the lens barrel 100 according to this embodiment, the first lens holding frame F1 and the second lens holding frame F2 are biased in the direction of abutting against the walls 21a and 21b of the straight groove 21 by the block 50 and the compression spring 51, respectively, in the three straight grooves 21, so that excessive force is not applied to the first lens holding frame F1 and the second lens holding frame F2. Therefore, even if a small stepping motor with a relatively small torque is used, the first lens holding frame F1 and the second lens holding frame F2 can be driven. This allows the first lens holding frame F1 and the second lens holding frame F2 to be moved with high precision in the optical axis OA direction.

In addition, according to this embodiment, the first protrusion 31, the second protrusion 41, and the block 50 each have a bearing. This reduces the sliding resistance when the first lens holding frame F1 and the second lens holding frame F2 move.

In addition, according to this embodiment, the second fixed barrel 20 has a plurality of linear grooves 21, and the stepping motor 601 and the stepping motor 701 are disposed between two of the linear grooves 21 that are disposed side by side in the circumferential direction centered on the optical axis OA. This allows the stepping motor 601 and the stepping motor 701 to be disposed in a well-balanced manner. In addition, since the stepping motors 601 and 701 can be disposed in the empty space between the first fixed barrel 10 and the second fixed barrel 20, the lens barrel 100 can be made smaller.

In addition, according to this embodiment, the lens barrel 100 includes a lead screw 602 rotated by a stepping motor 601, and a rack body 611 held by the first lens holding frame F1 and engaging with the lead screw 602. The rack body 611 includes a first side wall portion 611a, a second side wall portion 611b, and a connection 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 connection portion 611c are configured from a single member. This reduces the number of parts, and therefore reduces failures compared to when the rack body 611 is configured from multiple members.

Furthermore, the first side wall portion 611a has a first contact portion 613a that contacts the lead screw 602, and the second side wall portion 611b has a second contact portion 613b that contacts the lead screw 602, and the lens barrel 100 is provided with a biasing member 612 that biases the rack body 611 so that the first contact portion 613a and the second contact portion 613b approach each other. As a result, the threads formed on the inner surfaces of the first contact portion 613a and the second contact portion 613b come into close contact with the threads formed on the lead screw 602, thereby suppressing rattling.

In addition, for example, when one of the first side wall portion 611a and the second side wall portion 611b is biased using a torsion spring or the like to bring the thread formed on the inner surface of the first contact portion 613a or the second contact portion 613b into close contact with the thread formed on the lead screw 602, the reaction force of the force against the first side wall portion 611a or the second side wall portion 611b is applied to the first lens holding frame F1 via the rack body 611 and the rack holding shaft 331, affecting the first lens holding frame F1 supported in a balanced manner by the three straight grooves 21. In this embodiment, the first contact portion 613a and the second contact portion 613b are biased toward the lead screw 602 with approximately the same force, so no reaction force is generated in the rack body 611. Therefore, it is possible to suppress the application of unnecessary force to the first lens holding frame F1. As a result, the first lens holding frame F1 can be held in a balanced manner within the second fixed barrel 20. The same applies to the second lens holding frame F2.

As described in detail, the lens barrel 100 according to this embodiment includes a stepping motor 601, a lead screw 602 rotated by the stepping motor 601, a rack 603 engaging with the lead screw 602, a first lens holding frame F1 that holds the first lens group L1, and a second fixed barrel 20 that is disposed on the outer periphery side of the first lens holding frame F1, and the peripheral wall of the second fixed barrel 20 is present between the lead screw 602 and the first lens holding frame F1. Since the peripheral wall of the second fixed barrel 20 is interposed between the first lens holding frame F1 and the lead screw 602, compared to the case where the lead screw 602 is disposed between the second fixed barrel 20 and the first lens holding frame F1 (the case where the lead screw 602 is disposed on the inner periphery side of the second fixed barrel 20), it is possible to suppress adhesion of the lubricant applied to the lead screw 602 and dust generated by the sliding between the lead screw 602 and the rack 603 to the first lens group L1 and the second lens group L2.

Also, according to this embodiment, the lens barrel 100 includes a mounting member 604 that fixes the stepping motor 601 to the second fixed barrel 20, and the lead screw 602 is disposed on the outer periphery side of the third portion 604c of the mounting member 604. Also, according to this embodiment, the rack 603 is disposed on the outer periphery side of the third portion 604c of the mounting member 604. Furthermore, the rack 603 is disposed on the outer periphery side of the second fixed barrel 20. As a result, the components of the first drive source unit 60 that drives the first lens holding frame F1 can be disposed on the outer periphery 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 holding frame F1, so that the second fixed barrel 20 can prevent dust from adhering to the first lens group L1 and the second lens group L2. The same applies to the second drive source unit 70.

In addition, according to this embodiment, the second fixed barrel 20 has a hole 22 for positioning the rack 603 on the outer periphery side of the second fixed barrel 20. Since there is no need to form any holes other than the hole 22 in the wall surface of the portion of the second fixed barrel 20 that houses the first lens holding frame F1 and the second lens holding frame F2, light leakage can be suppressed.

Furthermore, according to this embodiment, the first lens holding frame F1 has a light blocking portion 334 that is detected by a photointerrupter (not shown) that detects the position of the first lens holding frame F1, and the light blocking portion 334 is disposed on the outer periphery side of the second fixed barrel 20. This allows the second fixed barrel 20 to block light from the light emitting portion of the photointerrupter, thereby reducing the effect of the light from the photointerrupter on imaging.

In the above embodiment, it is sufficient that at least a portion of the stepping motor 601 is disposed on the outer periphery side of the second fixed barrel 20. In other words, a portion of the stepping motor 601 may be disposed on the inner periphery side of the second fixed barrel 20.

In addition, in the above embodiment, the second fixed barrel 20 that houses the first lens holding frame F1 and the second lens holding frame F2 may be a movable barrel that can move linearly in the direction of the optical axis OA. In addition, in the above embodiment, the lens barrel 100 may be a fixed focal length lens or a zoom lens.

The first drive source unit 60 and the second drive source unit 70 according to the above embodiment may also be applied to a guide bar type lens barrel in which the first lens holding frame F1 and the second lens holding frame F2 are moved linearly in the optical axis OA direction along a guide bar.

The lens barrel 100 may have only one of the first lens holding frame F1 and the second lens holding frame F2. In other words, from the viewpoint of preventing the intrusion of dust and the like, the configuration in which the peripheral wall of the second fixed barrel 20 is 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.

In the above embodiment, at least one of the bearing 311 of the first protrusion 31 and the bearing 411 of the second protrusion 41 may have a diameter different from the other bearings 311 and 411. For example, one of the two bearings 311 may have a diameter different from the other bearing 311. Also, one of the two bearings 411 may have a diameter different from the other bearing 411. Also, one of the two bearings 311 may have a diameter different from one or both of the two bearings 411. Also, the two bearings 311 and the two bearings 411 may all have diameters different from each other. In this way, by changing the diameters of the bearings 311 and 411, it is possible to perform tilt adjustment and centering of the first lens holding frame F1 and the second lens holding frame F2.

In the above embodiment, the compression spring 51 is provided between the first protrusion 31 and the block 50, but this is not limited to the above. Here, an example of the arrangement of the first protrusion 31 and the second protrusion 41 in a modified example will be described with reference to Figures 9(A) to 11(B).

(Variation 1)
Fig. 9(A) is a diagram showing an example of the arrangement of a first protrusion 31A and a second protrusion 41A according to Modification 1. Fig. 9(B) is a diagram showing a state in which bearings 311 and 411 are removed from Fig. 9(A).

As shown in FIG. 9A, in the first modification, the first protrusion 31A has a bearing 311, which abuts against one wall 21a of the linear groove 21. The second protrusion 41A has a bearing 411, which abuts against the other wall 21b of the linear groove 21.

Two pressing members 81 are provided between the first protrusion 31A and the second protrusion 41A. As shown in FIG. 9B, 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 by a tension spring 82. When the pressing members 81 are pulled by the tension spring 82, the protrusions 312 and 412 are pressed along the inclined surface 81a formed on the other end of the pressing member 81 in a direction in which the first protrusion 31A and the second protrusion 41A move away from each other. As a result, the first protrusion 31A and the second protrusion 41A are pressed against the walls 21b and 21a, respectively, suppressing rattling when the first lens holding frame F1 and the second lens holding frame F2 move linearly in the optical axis OA direction along the linear groove 21.

(Variation 2)
10 is a diagram showing an example of the arrangement of the first protrusion 31B and the second protrusion 41B according to the modified example 2. In the modified example 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. As shown by the arrow A21, the compression spring 87 biases the first block 85 and the second block 86 in a direction in which the first block 85 and the second block 86 move away from each other. As a result, the first block 85 and the second block 86 push up the inclined surfaces 313a and 313b formed on the first protrusion 31B, respectively, and also push up the inclined surfaces 413a and 413b formed on the second protrusion 41B, respectively. As a result, the first protrusion 31B and the second protrusion 41B are forced in a direction away from each other and pressed against the walls 21a and 21b, respectively, thereby suppressing rattling when the first lens retaining frame F1 and the second lens retaining frame F2 move straight along the straight-line groove 21 in the direction of the optical axis OA.

(Variation 3)
11A is a diagram showing an arrangement example of the first protrusion 31C and the second protrusion 41C according to the third modification, and FIG. 11B is a cross-sectional view taken along the line D-D in FIG. 11A. As shown in FIG. 11A, in the third modification, the straight groove 21 of the second fixed barrel 20 has a protrusion 211, and the first protrusion 31C and the second protrusion 41C are connected by a tension spring 88. The first protrusion 31C has a bearing 311 and abuts against one side wall 211a of the protrusion 211. The second protrusion 41C has a bearing 411 and abuts against the other side wall 211b of the protrusion 211. The tension spring 88 biases the first protrusion 31C and the second protrusion 41C in a direction in which the first protrusion 31 and the second protrusion 41 approach each other. As a result, the first protrusion 31C is pressed against the side wall portion 211a, and the second protrusion 41C is pressed against the side wall portion 211b, thereby suppressing rattling when the first lens retaining frame F1 and the second lens retaining frame F2 move straight along the straight-line groove 21 in the direction of the optical axis OA.

The configuration of the rack 603 is not limited to the above embodiment. Figs. 12(A) and 12(B) are diagrams showing a rack 603A according to a modified example. As shown in Fig. 12(A), the rack body 611A of the rack 603A includes a first side wall portion 611a, a second side wall portion 611b, and a connection portion 611c that connects 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 connection portion 611c are configured from a single member.

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 by a tension spring 612A. As a result, the first contact portion 613a and the second contact portion 613b are biased obliquely in a direction approaching each other as shown by the arrow A22 in FIG. 12(B). As a result, the thread formed on the inside of the first contact portion 613a and the thread formed on the inside of the second contact portion 613b are in close contact with the thread of the lead screw 602, so that rattle can be suppressed. In addition, since the first contact portion 613a and the second contact portion 613b are biased toward the lead screw 602 with approximately the same force, no reaction force is generated in the rack body 611A. Therefore, it is possible to suppress the application of unnecessary force to the first lens holding frame F1. This allows the first lens holding frame F1 to be held in a well-balanced manner within the second fixed barrel 20.

The above-described embodiment is a preferred example. However, the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention, and any combination of components may be used.

1 Camera 10 First fixed barrel 20 Second fixed barrel 21 Linear grooves 21a, 21b Wall 22 Hole 31 First protrusion 41 Second protrusion 50 Block 51 Compression spring 60 First drive source unit 70 Second drive source unit 100 Lens barrel 311, 411, 501 Bearing 601, 701 Stepping motor 602, 702 Lead screw 603, 703 Rack 611 Rack body 611a First side wall portion 611b Second side wall portion 611c Connection portion 612 Pressing member 612A Tension spring 613a First contact portion 613b Second contact portion F1 First lens holding frame F2 Second lens holding frame L1 First lens group L2 Second lens group

Claims (19)

A first driving source;
A second drive source;
a first rotating shaft rotated by the first driving source;
a second rotating shaft rotated by the second driving source;
a first lens holding frame having a first engagement portion that engages with the first rotation shaft and that holds a first lens;
a second lens holding frame having a second engagement portion that engages with the second rotation shaft and that holds a second lens;
an outer cylinder disposed on an outer circumferential side relative to the first lens holding frame and the second lens holding frame ;
Equipped with
the first lens holding frame is moved in the optical axis direction by the driving force of the first driving source,
the second lens holding frame is moved in the optical axis direction by a driving force of the second driving source,
a peripheral wall of the outer cylinder is present between the first rotation shaft and the first lens holding frame,
a peripheral wall of the outer cylinder is present between the second rotation shaft and the second lens holding frame,
the first lens holding frame has a first shaft holding portion that holds the first engagement portion,
the second lens holding frame has a second shaft holding portion that holds the second engagement portion,
The first engagement portion is rotatable about the first shaft holding portion,
The second engagement portion is rotatable about the second shaft holding portion,
the outer cylinder has a hole for disposing the first engagement portion and the second engagement portion on an outer circumferential side of the outer cylinder,
the first driving source, the second driving source, and the hole are disposed in a range in which a distance between the first rotation axis and the second rotation axis is shorter in a circumferential direction of a circle centered on an optical axis,
Lens barrel. the first engagement portion has a first contact portion that comes into contact with the first rotation shaft,
the second engagement portion has a second contact portion that comes into contact with the second rotation shaft,
the first contact portion and the first shaft holding portion are disposed on substantially the same circumference of a circle centered on the optical axis ,
the second contact portion and the second shaft holding portion are disposed on substantially the same circumference of a circle centered on the optical axis,
The lens barrel according to claim 1 . the first engagement portion has a first biasing member that biases the first engagement portion in a direction toward the first rotation shaft ,
The second engagement portion has a second biasing member that biases the second engagement portion in a direction of the second rotation shaft.
The lens barrel according to claim 1 or 2. The first engagement portion is
At least two first contact portions that come into contact with the first rotating shaft;
a first biasing member that biases the first contact portion in a direction toward the first rotation axis ,
The second engagement portion is
At least two second contact portions that come into contact with the second rotating shaft;
and a second biasing member that biases the second contact portion in a direction toward the second rotation axis.
The lens barrel according to claim 1 . the force with which the first biasing member biases the at least two first contact portions is substantially equal;
The force with which the second biasing member biases the at least two second contact portions is substantially equal.
The lens barrel according to claim 4. the first lens holding frame has a first protrusion protruding toward an outer periphery,
the second lens holding frame has a second protrusion protruding toward an outer periphery,
the outer cylinder has a linear groove on an inner circumferential surface with which the first protrusion and the second protrusion engage,
the first protrusion and the second protrusion move in the optical axis direction relative to the rectilinear groove, thereby guiding the movement of the first lens holding frame and the second lens holding frame in the optical axis direction.
The lens barrel according to any one of claims 1 to 5. The first protrusion has a first bearing ,
The second protrusion has a second bearing.
The lens barrel according to claim 6. a first fixing portion that fixes the first driving source to the outer cylinder ;
a second fixing portion that fixes the second driving source to the outer cylinder;
Equipped with
the first rotating shaft is disposed on an outer circumferential side of the first fixed portion ,
The second rotating shaft is disposed on an outer circumferential side of the second fixed portion.
The lens barrel according to any one of claims 1 to 7. the first engagement portion is disposed on an outer circumferential side of the first fixed portion ,
The second engagement portion is disposed on an outer circumferential side of the second fixed portion.
The lens barrel according to claim 8. the first fixing portion has a first portion that fixes the first driving source,
the first shaft holding portion is disposed closer to the first engagement portion than the first portion in the optical axis direction ,
the second fixing portion has a second portion that fixes the second driving source,
the second shaft holder is disposed closer to the second engagement portion than the second portion in the optical axis direction;
The lens barrel according to claim 8. the first fixing portion has a U-shaped first mounting member including a first portion and a second portion that are substantially parallel to an optical axis and perpendicular to the optical axis, and a third portion that is perpendicular to the first portion;
a hole through which a fixing screw for fixing the first driving source to the outer cylinder passes is formed in the third portion;
the second fixing portion has a U-shaped second mounting member including a fourth portion and a fifth portion that are substantially parallel to the optical axis and perpendicular to the optical axis, and a sixth portion that is perpendicular to the fourth portion;
a hole through which a fixing screw for fixing the second driving source to the outer cylinder passes is formed in the sixth portion;
The lens barrel according to claim 8. The first engagement portion is disposed on an outer circumferential side of the outer cylinder ,
The second engagement portion is disposed on an outer circumferential side of the outer cylinder.
The lens barrel according to any one of claims 1 to 11. The outer cylinder has a hole for disposing the first engagement portion and the second engagement portion on an outer circumferential side of the outer cylinder.
The lens barrel according to any one of claims 1 to 12. the first driving source and the second driving source are disposed on an outer circumferential side of the outer cylinder, at positions facing each other across the hole , such that the first rotation axis and the second rotation axis are aligned in a direction parallel to an optical axis ;
The lens barrel according to claim 13. At least a portion of the first driving source is disposed on an outer circumferential side of the outer cylinder ,
At least a portion of the second driving source is disposed on an outer circumferential side of the outer cylinder.
The lens barrel according to any one of claims 1 to 14. the first lens holding frame has a first detection portion that is detected by a first detection portion that detects a position of the first lens holding frame,
the first detection portion is disposed on an outer circumferential side of the outer cylinder ,
the second lens holding frame has a second detection portion that is detected by a second detection portion that detects a position of the second lens holding frame,
The second detection target portion is disposed on an outer circumferential side of the outer cylinder.
The lens barrel according to any one of claims 1 to 15. the first driving source and the second driving source are disposed substantially symmetrically with respect to the hole in a circumferential direction of a circle centered on the optical axis.
The lens barrel according to any one of claims 1 to 16 . A first driving source;
A second drive source;
a first rotating shaft rotated by the first driving source;
a second rotating shaft rotated by the second driving source;
a first lens holding frame having a first engagement portion that engages with the first rotation shaft and that holds a first lens;
a second lens holding frame having a second engagement portion that engages with the second rotation shaft and that holds a second lens;
an outer cylinder disposed on an outer circumferential side relative to the first lens holding frame and the second lens holding frame ;
Equipped with
the first lens holding frame is moved in the optical axis direction by the driving force of the first driving source,
the second lens holding frame is moved in the optical axis direction by a driving force of the second driving source,
a peripheral wall of the outer cylinder is present between the first rotation shaft and the first lens holding frame on a line connecting an optical axis and the central axis of the first rotation shaft within all planes perpendicular to the central axis of the first rotation shaft ,
a peripheral wall of the outer cylinder is present between the second rotation shaft and the second lens holding frame on a line connecting an optical axis and the central axis of the second rotation shaft within all planes perpendicular to the central axis of the second rotation shaft,
the first lens holding frame has a first shaft holding portion that holds the first engagement portion,
the second lens holding frame has a second shaft holding portion that holds the second engagement portion,
In a circumferential direction of a circle centered on the optical axis, a position where the first shaft holder holds the first engagement portion is different from a position where the first engagement portion engages with the first rotation shaft ,
In a circumferential direction of a circle centered on the optical axis, a position where the second shaft holder holds the second engagement portion is different from a position where the second engagement portion engages with the second rotation shaft,
the outer cylinder has a hole for disposing the first engagement portion and the second engagement portion on an outer circumferential side of the outer cylinder,
the first driving source, the second driving source, and the hole portion are disposed in a range in which a distance between the first rotation axis and the second rotation axis is shorter in a circumferential direction around the optical axis;
Lens barrel. An imaging device comprising the lens barrel according to any one of claims 1 to 18 .

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