Lens barrel and imaging device

Abstract

To increase the optical performance of this lens barrel, the lens barrel is made to comprise a diaphragm unit (30) that adjusts the light amount of a light flux passing through the lens barrel, and a first frame (F4) having at least one lens and provided with a first engagement portion (51) which engages with a first guide bar (25) extending in the optical axis direction. The diaphragm unit (30), the lens (L3), and the first frame (F4) integrally move in the optical axis direction.

Description

Lens barrel and imaging device

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

[0002] High optical performance is required of lens barrels (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2018-180357

[0004] According to a first aspect, the lens barrel comprises an aperture section that adjusts the amount of light of the light beam passing through, and a first frame having at least one lens and a first engagement section that engages with a first guide bar extending in the optical axis direction, and the aperture section, the lens, and the first frame move integrally in the optical axis direction.

[0005] According to a second aspect, an imaging device includes the lens barrel described above.

[0006] The configurations 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 particularly limited in terms of their placement may be placed in any position that can achieve their function, not limited to the placement disclosed in the embodiments.

[0007] FIG. 1 is a schematic diagram of a camera including a lens barrel and a camera body according to a first embodiment. FIG. 2 is a perspective view showing a subassembly and a drive unit included in the lens barrel. FIG. 3 is an exploded perspective view of the subassembly as viewed from the subject side. FIG. 4 is an exploded perspective view of the subassembly as viewed from the image plane side. FIG. 5(A) is a plan view of the subassembly as viewed from the subject side, and FIG. 5(B) is a cross-sectional view along line B-B in FIG. 5(A). FIG. 6 is a cross-sectional view of a lens holding frame. FIG. 7 is a perspective view for explaining an intermediate frame. FIG. 8 is a perspective view showing the subassembly and a lens holding frame of a focus lens. FIG. 9(A) is a plan view of the subassembly as viewed from the subject side, and FIG. 9(B) is a plan view of the subassembly and lens holding frame of a focus lens as viewed from the subject side. FIG. 10(A) is a perspective view of the subassembly according to a second embodiment as viewed from the subject side, and FIG. 10(B) is a perspective view of the subassembly as viewed from the image plane side. FIG. 11 is an exploded perspective view of the subassembly as viewed from the subject side. Fig. 12 is an exploded perspective view of the sub-assembly as seen from the image plane side, Fig. 13(A) is a plan view of the sub-assembly as seen from the image plane side, and Fig. 13(B) is a cross-sectional view taken along line AA in Fig. 13(A).

[0008] First Embodiment A lens barrel according to a first embodiment will now be described with reference to the drawings. Note that the scales of the shapes, lengths, thicknesses, and other aspects of the components shown in the embodiment do not necessarily correspond to the actual products, and parts that are not necessary for the explanation have been omitted or simplified as appropriate.

[0009] 1 is a schematic diagram of a camera 1 including a lens barrel 20 according to this embodiment and a camera body 10. In this embodiment, the lens barrel 20 is detachable from the camera body 10 by a lens mount LM. Note that the lens barrel 20 and the camera body 10 may be integrated.

[0010] The camera body 10 includes an image sensor IS and a control unit CU. The image sensor IS includes a photoelectric conversion element such as a CCD (Charge Coupled Device), and converts the subject image formed by the imaging optical system (lens barrel 20 attached to the camera body 10) into an electrical signal.

[0011] The control unit CU is equipped with a CPU (Central Processing Unit) and the like, and controls the overall operation of the camera 1 related to photography, including zoom operation, focusing drive, aperture adjustment, and blur correction of captured images due to camera shake, etc., in the camera body 10 and the attached lens barrel 20.

[0012] 1, the lens barrel 20 according to this embodiment includes a first fixed barrel 21, a second fixed barrel 22 disposed inside the first fixed barrel 21, and a zoom operation ring 23. In this embodiment, the first fixed barrel 21 and the second fixed barrel 22 are made up of multiple components, but they may also be made up of a single component.

[0013] The lens barrel 20 also includes a plurality of lens groups L1 to L6 arranged in sequence along a common optical axis OA. The lens groups L1 and L6 are held by a second fixed barrel 22. The lens groups L2 to L5 are held by lens holding frames F2 to F5, respectively. The lens groups L2 and L4 are zoom lens groups, the lens group L3 is a vibration reduction (VR) lens group, and the lens group L5 is a focus lens group. Each of the lens groups L1 to L6 may be composed of a single lens or multiple lenses.

[0014] The lens barrel 20 also has a first guide bar 25, a second guide bar 26 (not shown in FIG. 1 ), and a sub-guide bar 27. The first guide bar 25, the second guide bar 26, and the sub-guide bar 27 are fixed to the second fixed barrel 22.

[0015] The first guide bar 25 guides the lens retaining frame F4 in the direction of the optical axis OA, and the second guide bar 26 guides the lens retaining frame F5 in the direction of the optical axis OA. The sub-guide bar 27 regulates the rotation of the lens retaining frame F4 about the first guide bar 25 and the rotation of the lens retaining frame F5 about the second guide bar 26. In this embodiment, the lens retaining frames F4 and F5 share the sub-guide bar 27, but separate sub-guide bars may be provided for the lens retaining frames F4 and F5.

[0016] In this embodiment, the lens barrel 20 also includes a subassembly G1 that includes an aperture mechanism 30 that adjusts the amount of light emitted from the light beam, a correction mechanism 40 that corrects image blur, and a lens holding frame F4.

[0017] The sub-assembly G1 is driven by the first drive source unit 100. The sub-assembly G1 and the first drive source unit 100 will be described in detail below.

[0018] Fig. 2 is a perspective view showing the sub-assembly G1 and the first drive source unit 100. Fig. 3 is an exploded perspective view of the sub-assembly G1 as seen from the subject side, and Fig. 4 is an exploded perspective view of the sub-assembly G1 as seen from the image plane side. Fig. 5(A) is a plan view of the sub-assembly G1 as seen from the subject side, and Fig. 5(B) is a cross-sectional view taken along line B-B in Fig. 5(A). Fig. 6 is a cross-sectional view of the lens holding frame F4 included in the sub-assembly G1.

[0019] First, the detailed configuration of the sub-assembly G1 will be described. The sub-assembly G1 includes an aperture mechanism 30, a correction mechanism 40, and a lens holding frame F4.

[0020] 3 and 4 , the diaphragm mechanism 30 is an iris diaphragm whose aperture diameter is adjustable. The diaphragm mechanism 30 includes a lens holding frame F2, a plurality of diaphragm blades 32, a rotary frame 33, a stepping motor 34, and an intermediate frame 60.

[0021] The lens holding frame F2 includes a lens holding portion 36 (see FIG. 3) that holds the lens group L2, and a plurality of holes 31 (see FIG. 4) formed on the surface facing the image plane. The number of the holes 31 is the same as the number of diaphragm blades 32, and a support portion 32 a of the diaphragm blade 32 is inserted into each hole 31.

[0022] A support portion 32a is provided on the subject-side surface of each of the plurality of diaphragm blades 32, and a cam follower 32b is provided on the image-plane-side surface. The support portion 32a is inserted into a hole 31 provided in the lens holding frame F2, and the cam follower 32b is inserted into a cam groove 33a (see FIG. 3) provided in the rotary frame 33.

[0023] The rotary frame 33 is an annular member having an opening in the center, and is formed with cam grooves 33a in the same number as the number of diaphragm blades 32. As described above, the cam followers 32b of the diaphragm blades 32 are inserted into the cam grooves 33a. Note that the cam grooves 33a may be through grooves that pass through the rotary frame 33, or may be grooves that do not pass through the rotary frame 33.

[0024] A segment gear 33 b is formed on the outer edge of the rotary frame 33 (see FIG. 4 ), and meshes with a pinion gear 34 a attached to the rotary shaft of a stepping motor 34 .

[0025] As shown in FIG. 5B, the stepping motor 34 is held by the intermediate frame 60 so as to protrude toward the lens holding frame F3.

[0026] When a command to change the F-number is issued from the camera body 10, the stepping motor 34 is driven to rotate, causing the rotary frame 33, which has a segment gear 33b that meshes with a pinion gear 34a attached to the rotary shaft of the stepping motor 34, to rotate. The cam followers 32b of the diaphragm blades 32 are inserted into cam grooves 33a of the rotary frame 33. Therefore, when the rotary frame 33 rotates around the optical axis OA, the cam followers 32b of the diaphragm blades 32 rotate along the cam grooves 33a, with the support portions 32a as fulcrums. This allows the size of the aperture of the iris diaphragm to be adjusted by the multiple diaphragm blades 32. Note that the cam grooves 33a may be provided in the lens holding frame F2, and the holes 31 may be provided in the rotary frame 33.

[0027] (Correction Mechanism 40) The correction mechanism 40 includes an intermediate frame 60, a lens holding frame F3, a pair of voice coil motors (hereinafter referred to as VCMs) 42a and 42b, and a lens holding frame F4.

[0028] The lens holding frame F3 holds the lens group L3, which is a focus lens group, and is connected to the lens holding frame F4 in the optical axis OA direction by a spring (not shown).

[0029] The lens holding frame F3 is driven by VCMs 42a and 42b. The VCM 42a includes a magnet 43a and a coil 44a, and the VCM 42b includes a magnet 43b and a coil 44b. The magnets 43a and 43b are held by magnet holders 45a and 45b, respectively, of the lens holding frame F3, and the coils 44a and 44b are held by coil holders 52a and 52b, respectively (coil holder 52a is not shown), of the lens holding frame F4.

[0030] By passing a current through the coils 44a and 44b, an electromagnetic force acts on the lens holding frame F3 via the magnets 43a and 43b in a direction intersecting (orthogonal to) the optical axis OA, and the lens group L3 (image blur correction lens group) is shifted in that direction together with the lens holding frame F3. By using the pair of VCMs 42a and 42b, the lens group L3 can be shifted in two directions intersecting the optical axis OA, and the lens group L3 can be driven in any direction intersecting the optical axis OA.

[0031] In this embodiment, a so-called moving magnet type VCM is used, but a moving coil type VCM in which the lens holding frame F3 holds a coil and the lens holding frame F4 holds a magnet may also be used.

[0032] (Intermediate Frame 60) An intermediate frame 60 is provided between the rotary frame 33 and the lens holding frame F3, and the diaphragm mechanism 30 and the correction mechanism 40 share the intermediate frame 60. Fig. 7 is a perspective view for explaining the intermediate frame 60.

[0033] As described above, the intermediate frame 60 holds the stepping motor 34 of the diaphragm mechanism 30 so that the stepping motor 34 protrudes toward the lens holding frame F3. Therefore, as shown in FIG. 5B , the stepping motor 34 and the VCMs 42a, 42b overlap in the radial direction of a circle centered on the optical axis OA. In other words, a plane that includes the stepping motor 34 and is perpendicular to the optical axis OA intersects with the VCMs 42a, 42b. That is, the stepping motor 34 and the VCMs 42a, 42b are not stacked in the direction of the optical axis OA.

[0034] As a result, compared to when the stepping motor 34 and the VCMs 42a, 42b do not overlap in the radial direction of a circle centered on the optical axis OA, the length of the subassembly G1 in the optical axis OA direction can be shortened, thereby making it possible to reduce the size of the lens barrel 20. Furthermore, because the diaphragm mechanism 30 and the correction mechanism 40 share the intermediate frame 60, the number of parts can be reduced compared to when the diaphragm mechanism 30 and the correction mechanism 40 are provided separately, and the parts cost of the lens barrel 20 can be reduced.

[0035] 7, a Hall element 61 for detecting the amount of movement of the lens holding frame F3 (lens group L3) is attached to the intermediate frame 60. The position of the lens group L3 can be detected by detecting the magnetic field of the magnets 43a and 43b fixed to the lens holding frame F3 with the Hall element 61.

[0036] The intermediate frame 60 is also provided with a detector 62 that detects whether the aperture is in the fully open position. The detector 62 includes a light-emitting element 62a that emits light and a light-receiving element 62b that receives the light emitted by the light-emitting element 62a. The detector 62 is, for example, a photointerrupter. A light-shielding plate 33c extending toward the image plane is provided on the outer periphery of the rotary frame 33 (see FIG. 4). As the rotary frame 33 rotates relative to the intermediate frame 60, the light-shielding plate 33c moves within a light-shielding plate slit 63 (see FIGS. 3 and 7) provided in the intermediate frame 60. When the light-shielding plate 33c passes between the light-emitting element 62a and the light-receiving element 62b, a detection circuit (not shown) detects that the aperture is in the fully open position.

[0037] By providing the Hall element 61 and the detection unit 62 in the same component (intermediate frame 60), routing of the flexible printed circuit board can be simplified.

[0038] 7, in a plane perpendicular to the optical axis OA, the Hall element 61 and the stepping motor 34 are disposed on opposite sides of the optical axis OA. If the Hall element 61 and the stepping motor 34 are close to each other, there is a risk that noise may be carried over to the signal from the Hall element 61 due to the influence of the magnetic field of the stepping motor 34. In this embodiment, the Hall element 61 and the stepping motor 34 are disposed at a distance from each other, which makes it possible to prevent noise from being carried over to the signal from the Hall element 61.

[0039] The intermediate frame 60 is fixed to the lens holding frame F2 by inserting screws 72 into holes 29 (see FIG. 4) formed in the lens holding frame F2. This restricts movement of the diaphragm blades 32 and the rotary frame 33 in the direction of the optical axis OA by the intermediate frame 60. The lens holding frame F2 is fixed to the lens holding frame F4 by inserting screws 71 into holes 59 (see FIG. 3, etc.) formed in the lens holding frame F4. This fixes the diaphragm mechanism 30 to the lens holding frame F4.

[0040] (Lens holding frame F4) As shown in Figure 6, the lens holding frame F4 has a cylindrical portion 53 that holds the lens group L4, and the outer periphery of the cylindrical portion 53 is provided with a first engagement portion 51 that engages with the first guide bar 25 and a second engagement portion 54 (see Figure 3) that engages with the sub-guide bar 27.

[0041] 6, the first engagement portion 51 has a first end 51a and a second end 51b that face each other in the direction of the optical axis OA. A through hole 51c is formed in the first end 51a and the second end 51b. The first guide bar 25 is inserted through the through hole 51c. The first engagement portion 51 slides relative to the first guide bar 25, thereby guiding the lens holding frame F4 in the direction of the optical axis OA.

[0042] The sub-assembly G1 is driven by driving the lens holding frame F4 by a first drive source unit 100. As shown in FIG. 2 , the first drive source unit 100 includes a stepping motor 101, a lead screw 102, a nut 103, a rotation restriction bar 104, and an attachment member 105.

[0043] The mounting member 105 is fixed to the stepping motor 101 and rotatably supports the lead screw 102. As shown in Fig. 2, a plurality of holes 105a are formed in the mounting member 105, and the first drive source unit 100 is fixed to the second fixed barrel 22 by fastening the mounting member 105 to the second fixed barrel 22 with screws.

[0044] The lead screw 102 is directly connected to the output shaft of the stepping motor 101 and is rotationally driven by the stepping motor 101. The lead screw 102 extends in the direction of the optical axis OA, and a screw groove is formed on the outer periphery of the lead screw 102. A nut 103 that surrounds the entire periphery of the lead screw 102 is engaged with the lead screw 102.

[0045] The nut 103 has an engagement portion 103a that engages with the rotation restriction bar 104. The rotation restriction bar 104 is supported by a support portion 51d provided on the first engagement portion 51 of the lens holding frame F4. As a result, the rotation of the nut 103 is restricted by the rotation restriction bar 104, and when the lead screw 102 is rotated by the stepping motor 101, the nut 103 moves linearly in the direction of the optical axis OA.

[0046] A spring 110 is provided between the engaging portion 103a of the nut 103 and the support portion 51d of the lens holding frame F4. A rotation restricting bar 104 is inserted into the spring 110. The spring 110 biases the nut 103 and the support portion 51d so that the nut 103 is pressed against the support portion 51d.

[0047] Because the nut 103 is pressed against the support portion 51d, when the nut 103 moves in the direction of the optical axis OA, the lens holding frame F4 moves in the direction of the optical axis OA together with the nut 103. This allows the lens holding frame F4 to be driven in the direction of the optical axis OA by driving and rotating the lead screw 102. Because the diaphragm mechanism 30 is fixed to the lens holding frame F4 via the correction mechanism 40, when the lead screw 102 is driven and rotated, the diaphragm mechanism 30, the correction mechanism 40, and the lens holding frame F4 move in the direction of the optical axis OA together.

[0048] (Lens Retaining Frame F5) Next, the relationship between the lens retaining frame F5 and the sub-assembly G1 will be described. Fig. 8 is a perspective view showing the sub-assembly G1 and the lens retaining frame F5. Fig. 9(A) is a plan view of the sub-assembly G1 as seen from the subject side, and Fig. 9(B) is a plan view of the sub-assembly G1 and the lens retaining frame F5 as seen from the subject side. Note that Fig. 8 shows the sub-assembly G1 and the lens retaining frame F5 in the closest position.

[0049] The lens holding frame F5 is disposed closer to the image plane than the sub-assembly G1 and has a third engaging portion 91 that engages with the second guide bar 26. The lens holding frame F5 is driven, for example, by a second driving source unit 200 having the same configuration as the first driving source unit 100. The second driving source unit 200 includes a stepping motor, a lead screw, a nut 203, a rotation restriction bar 204, and an attachment member, although the stepping motor, lead screw, and attachment member are not shown. The second driving source unit 200 is fixed to, for example, the second fixed barrel 22.

[0050] 9A, the sub-assembly G1 has an outer shape with a portion of a circle cut out to allow clearance for the third engagement portion 91 of the lens holding frame F5. As a result, as shown in FIGS. 8 and 9B, when the sub-assembly G1 and the lens holding frame F5 are closest to each other, the third engagement portion 91 overlaps with the sub-assembly G1 in the radial direction of a circle centered on the optical axis OA. In other words, the third engagement portion 91 overlaps with the diaphragm mechanism 30 and the correction mechanism 40 in the radial direction.

[0051] By doing this, the engagement length between the third engagement portion 91 of the lens holding frame F5 and the second guide bar 26 can be increased, thereby preventing the central axis of the lens group L5 from tilting relative to the optical axis OA, and improving the optical performance of the lens barrel 20.

[0052] As described in detail above, according to this first embodiment, the lens barrel 20 comprises an aperture mechanism 30 that adjusts the amount of light of the light beam passing through, a correction mechanism 40 (more specifically, lens group L3) that moves in a direction intersecting the optical axis OA to correct image blur, and a lens holding frame F4 that has a first engagement portion 51 that engages with a first guide bar 25 extending in the direction of the optical axis OA, and the aperture mechanism 30, the correction mechanism 40, and the lens holding frame F4 move together in the direction of the optical axis OA.

[0053] A possible configuration for moving a sub-assembly including the diaphragm mechanism 30 and the correction mechanism 40 in the direction of the optical axis OA is, for example, to provide a first cam follower and a second cam follower on the outer periphery of the sub-assembly, with the first cam follower engaging with a cam groove formed in a cam barrel that rotates around the optical axis OA in response to operation of the zoom operation ring 23, and the second cam follower engaging with a linear groove extending in the direction of the optical axis OA. In this configuration, the sub-assembly moves along the cam groove as the cam barrel rotates in response to operation of the zoom operation ring 23. At this time, the rotation of the sub-assembly around the optical axis OA is restricted by the linear groove, and the sub-assembly is guided in the direction of the optical axis OA by the linear groove, so that the sub-assembly can be moved in the direction of the optical axis OA without rotating.

[0054] However, steps are formed on the inner walls of the cam grooves and linear grooves during the manufacturing process of the cam barrel. Therefore, if linear grooves are used to guide the subassembly in the optical axis OA direction, unnecessary vibrations are generated when the second cam follower passes over the steps in the linear grooves, resulting in image skipping and image fluctuation. While such image skipping and image fluctuation do not affect still images, they do affect moving images. In this embodiment, the first guide bar 25 is used as a mechanism for guiding the subassembly G1 in the optical axis OA direction, thereby suppressing image skipping and image fluctuation and improving the optical performance of the lens barrel 20. Furthermore, the aperture mechanism 30 and correction mechanism 40, which are likely to affect optical performance, are guided in the optical axis OA direction by the first guide bar 25, further improving the optical performance of the lens barrel 20.

[0055] Furthermore, in this embodiment, the lens barrel 20 includes a first drive source unit 100 that drives the lens holding frame F4 in the optical axis OA direction. The diaphragm mechanism 30, the correction mechanism 40, and the lens holding frame F4 move together in the optical axis OA direction as a result of the driving of the first drive source unit 100. When the diaphragm mechanism 30 and the correction mechanism 40 are driven by cam grooves and cam followers formed in a cam barrel, image skipping / image shaking occurs when the cam followers pass through steps formed on the inner walls of the cam grooves. In contrast, in this embodiment, the first drive source unit 100 is used to drive the subassembly G1 including the diaphragm mechanism 30 and the correction mechanism 40, so image skipping / image shaking caused by steps formed on the cam grooves is eliminated. This further improves the optical performance of the lens barrel 20. The use of the first drive source unit 100 to drive the diaphragm mechanism 30 and the correction mechanism 40, which are likely to affect optical performance, further improves the optical performance of the lens barrel 20.

[0056] Furthermore, in this embodiment, the lens holding frame F4 engages with the first drive source unit 100 (more specifically, the lead screw 102) and holds a nut 103 that moves in the direction of the optical axis OA. Because the nut 103 engages with the lead screw 102 around its entire circumference, the subassembly G1 will not move even if, for example, the camera 1 (lens barrel 20) is dropped and the lens barrel 20 is subjected to an impact. This reduces the impact force applied to the subassembly G1, thereby preventing damage to the subassembly G1. Furthermore, damage to other components due to the subassembly G1 colliding with other components can be prevented. Furthermore, because there is no need to provide cushioning materials such as springs or rubber to absorb impact when the subassembly G1 collides with other components, the number of components can be reduced, thereby reducing the component costs of the lens barrel 20.

[0057] In this embodiment, the lens barrel 20 includes a stepping motor 34 that adjusts the aperture diameter of the diaphragm mechanism 30 and VCMs 42a, 42b that drive the correction mechanism 40 (more specifically, the lens group L3) in a direction intersecting the optical axis OA, and the stepping motor 34 and the VCMs 42a, 42b overlap in the radial direction of a circle centered on the optical axis OA. The lens barrel 20 also includes an intermediate frame 60 that holds the stepping motor 34, and the stepping motor 34 is held by the intermediate frame 60 so as to protrude toward the correction mechanism 40. This allows the length of the subassembly G1 in the optical axis OA direction to be shorter than in a case where the stepping motor 34 and the VCMs 42a, 42b do not overlap in the radial direction, thereby making it possible to reduce the size of the lens barrel 20.

[0058] In this embodiment, the lens barrel 20 also includes a detector 62 that detects the fully opened position of the aperture mechanism 30, a Hall element 61 that detects the position of the correction mechanism 40 (more specifically, the lens group L3) in a direction intersecting the optical axis OA, and an intermediate frame 60 that holds the detector 62 and the Hall element 61. For example, it is possible to provide the detector 62 on the lens holding frame F2 and the Hall element 61 on the lens holding frame F4, but this would complicate the routing of the flexible printed circuit board. In this embodiment, the Hall element 61 and the detector 62 are provided on the same component (the intermediate frame 60), which simplifies the routing of the flexible printed circuit board.

[0059] In this embodiment, the intermediate frame 60 holds the stepping motor 34 that adjusts the aperture diameter of the diaphragm mechanism 30, and in a plane perpendicular to the optical axis OA, the Hall element 61 and the stepping motor 34 are disposed on opposite sides of the optical axis OA. This separates the Hall element 61 and the stepping motor 34, making it possible to suppress noise from being introduced into the signal.

[0060] Furthermore, in this embodiment, the lens barrel 20 is provided with screws 71 that secure the lens retaining frame F4 to the diaphragm mechanism 30 (more specifically, the lens retaining frame F2), and the lens retaining frame F4 has holes 59 into which the screws 71 are inserted. The lens retaining frame F4, which has the first engaging portion 51 that engages with the first guide bar 25, requires high rigidity. This is because if the rigidity is low, the first engaging portion 51 that engages with the first guide bar 25 will tilt with respect to the optical axis OA, resulting in deterioration of optical performance.

[0061] Because the lens holding frame F4 has high rigidity, even when holes 59 are provided in the lens holding frame F4 and the diaphragm mechanism 30 is secured to the lens holding frame F4 with screws, the amount of deformation of the lens holding frame F4 is small. This prevents, for example, the central axis of the lens group L4 held by the lens holding frame F4 from tilting relative to the optical axis OA due to deformation of the lens holding frame F4. In other words, it is possible to prevent a deterioration in optical performance. Furthermore, by fixing the components that hold the lens groups together (the lens holding frame F2 and the lens holding frame F4) with screws 71, it is possible to prevent variations in optical performance due to component variations.

[0062] In this embodiment, the lens barrel 20 includes a lens holding frame F5 that holds a lens group L5 that moves along the optical axis OA during focusing, a second drive source unit 200 that drives the lens holding frame F5 along the optical axis OA, and a second guide bar 26 that guides the lens holding frame F5 along the optical axis OA. The lens holding frame F5 has a third engagement portion 91 that engages with the second guide bar 26, and when the lens holding frame F5, the diaphragm mechanism 30, and the correction mechanism 40 are closest to each other, the third engagement portion 91 overlaps with the diaphragm mechanism 30 and the correction mechanism 40 in the radial direction of a circle centered on the optical axis OA. In other words, the diaphragm mechanism 30, the correction mechanism 40, and the lens holding frame F4 have outer shapes that allow the third engagement portion 91 to escape. This allows the engagement length between the third engagement portion 91 of the lens holding frame F5 and the second guide bar 26 to be increased, thereby preventing the central axis of the lens group L5 from tilting relative to the optical axis OA and improving the optical performance of the lens barrel 20.

[0063] In this embodiment, the lens holding frame F2 holds the lens group L2, and the lens holding frame F4 holds the lens group L4. However, this is not limiting. For example, the lens holding frame F2 does not have to hold the lens group L2. Furthermore, the lens holding frame F4 does not have to hold the lens group L4.

[0064] Second Embodiment Next, a sub-assembly G1A according to a second embodiment will be described. In the first embodiment, the lens retaining frame F4 has the first engaging portion 51 that engages with the first guide bar 25, but this is not limited to this. In the second embodiment, a configuration will be described in which an intermediate frame 60A has a first engaging portion 51A that engages with the first guide bar 25.

[0065] Fig. 10(A) is a perspective view of the sub-assembly G1A according to the second embodiment as seen from the subject side, and Fig. 10(B) is a perspective view of the sub-assembly G1A as seen from the image plane side. Fig. 11 is an exploded perspective view of the sub-assembly G1A as seen from the subject side, and Fig. 12 is an exploded perspective view of the sub-assembly G1A as seen from the image plane side. Fig. 13(A) is a plan view of the sub-assembly G1A as seen from the image plane side, and Fig. 13(B) is a cross-sectional view taken along line A-A in Fig. 13(A).

[0066] The sub-assembly G1A according to the second embodiment includes a diaphragm mechanism 30A, a correction mechanism 40A, and an intermediate frame 60A.

[0067] (Aperture Mechanism 30A) The aperture mechanism 30A includes a lens holding frame F2A, a rotary frame 33A, a plurality of aperture blades 32, and an intermediate frame 60A.

[0068] The lens holding frame F2A holds the lens group L2. The lens holding frame F2A is fixed to the intermediate frame 60A by inserting screws 71A into holes 69 formed on the subject-side surface of the intermediate frame 60A. This fixes the diaphragm mechanism 30A to the intermediate frame 60A.

[0069] The rotary frame 33A is an annular member with an opening in the center, and has cam grooves 33a formed on the image plane side, the same number as the number of diaphragm blades 32. Cam followers 32b provided on the subject-side surfaces of the diaphragm blades 32 are inserted into the cam grooves 33a. The cam grooves 33a may be through grooves that pass through the rotary frame 33, or may be grooves that do not pass through the rotary frame 33A.

[0070] A segment gear 33b is formed on the outer edge of the rotary frame 33A and meshes with a pinion gear 34a attached to the rotary shaft of a stepping motor 34. The stepping motor 34 is held by the intermediate frame 60A.

[0071] A support portion 32a is provided on the image plane side surface of each of the plurality of diaphragm blades 32, and the support portion 32a is inserted into a hole 31 provided on the subject side surface of the intermediate frame 60A.

[0072] When a command to change the F-number is issued from the camera body 10, the stepping motor 34 is driven to rotate, causing the rotary frame 33A, which has a segment gear 33b that meshes with a pinion gear 34a attached to the rotary shaft of the stepping motor 34, to rotate. The cam followers 32b of the diaphragm blades 32 are inserted into the cam grooves 33a of the rotary frame 33A. Therefore, when the rotary frame 33A rotates around the optical axis OA, the cam followers 32b of the diaphragm blades 32 rotate along the cam grooves 33a, with the support portions 32a as fulcrums. This allows the size of the aperture of the iris diaphragm to be adjusted by the multiple diaphragm blades 32. Alternatively, the cam grooves 33a may be provided in the intermediate frame 60A, and the holes 31 may be provided in the rotary frame 33A.

[0073] (Correction Mechanism 40A) The correction mechanism 40A includes an intermediate frame 60A, a lens holding frame F3A, a pair of VCMs 42a and 42b, and a lens holding frame F4A.

[0074] The lens holding frame F3A is connected to the intermediate frame 60A in the optical axis OA direction by springs. The lens holding frame F3A is driven by VCMs 42a and 42b. The configuration of the VCMs 42a and 42b is the same as in the first embodiment. The magnets 43a and 43b are held by magnet holding portions 45a and 45b, respectively, of the lens holding frame F3A, and the coils 44a and 44b are held by coil holding portions 67a and 67b, respectively, of the intermediate frame 60A.

[0075] 13B, the stepping motor 34 held by the intermediate frame 60A and the VCMs 42a and 42b (VCM 42a not shown) overlap in the radial direction of a circle centered on the optical axis OA. This allows the length of the subassembly G1A in the optical axis OA direction to be shortened, as described in the first embodiment, and the lens barrel 20 to be made more compact.

[0076] The lens holding frame F4A holds the lens group L4, and is fixed to the intermediate frame 60A by inserting screws 72A into holes 68 formed on the object side of the intermediate frame 60A. In this embodiment, a Hall element 61 is provided on the image plane side surface of the lens holding frame F4 (see FIGS. 10B and 13A).

[0077] (Intermediate Frame 60A) The intermediate frame 60A includes a first engagement portion 51A that engages with the first guide bar 25 and a second engagement portion 54A that engages with the sub-guide bar 27. The intermediate frame 60A is driven by the first drive source unit 100 described in the first embodiment.

[0078] Specifically, by driving and rotating the lead screw 102 provided in the first drive source unit 100, the nut 103 engaged with the lead screw 102 moves in the direction of the optical axis OA, and the intermediate frame 60A engaged with the nut 103 moves in the direction of the optical axis OA. Because the diaphragm mechanism 30A and the correction mechanism 40A are fixed to the intermediate frame 60A, when the lead screw 102 is driven and rotated, the diaphragm mechanism 30A, the correction mechanism 40A, and the intermediate frame 60A move together in the direction of the optical axis OA.

[0079] As in the second embodiment, the first engagement portion 51A that engages with the first guide bar 25 may be provided on a frame that does not hold a lens group.

[0080] The above-described embodiment is a preferred example of implementation, but is not limited to this, and various modifications are possible within the scope of the gist, and any constituent elements may be combined.

[0081] REFERENCE SIGNS LIST 1 camera 10 camera body 20 lens barrel 22 second fixed barrel 25 first guide bar 26 second guide bar 30 diaphragm mechanism 34 stepping motor 40 correction mechanism 42a, 42b VCM 51 first engagement portion 59 hole 60, 60A intermediate frame 61 hall element 62 detection portion 71 screw 91 third engagement portion 100 first drive source unit 103 nut F4 lens holding frame F5 lens holding frame L4 lens group L5 lens group

Claims

1. A diaphragm for adjusting the amount of light passing through the light beam; a first frame having at least one lens and including a first engagement portion that engages with a first guide bar extending in the optical axis direction; Equipped with the diaphragm portion, the lens, and the first frame move integrally in the optical axis direction; Lens barrel.

2. a first drive unit that drives the first frame in the optical axis direction; The diaphragm unit, the lens, and the first frame are moved integrally in the optical axis direction by driving the first driving unit. The lens barrel according to claim 1 .

3. the first frame holds a nut that engages with the first drive portion and moves in the optical axis direction; The lens barrel according to claim 2 .

4. a correction unit that corrects image blur, the correction unit moving the lens in a direction intersecting with an optical axis; The lens barrel according to claim 1 .

5. a second drive unit for adjusting an opening diameter of the diaphragm unit; the correction unit has a third drive unit that drives the lens in a direction intersecting an optical axis, The second driving unit and the third driving unit overlap in a radial direction of a circle centered on the optical axis. The lens barrel according to claim 4.

6. a second frame that holds the second drive unit; The second drive unit is held by the second frame so as to protrude toward the correction unit. The lens barrel according to claim 5 .

7. A first detection unit that detects an open position of the throttle unit; A second detection unit that detects a position of the lens in a direction intersecting the optical axis; a second frame that holds the first detection unit and the second detection unit; The lens barrel according to claim 4 , comprising:

8. the second frame holds a second drive unit that adjusts an opening diameter of the diaphragm unit, The second detection unit and the second driving unit are disposed on opposite sides of the optical axis. The lens barrel according to claim 7.

9. a fixing portion that fixes the first frame and the diaphragm portion, The first frame has a hole into which the fixing portion is inserted. The lens barrel according to any one of claims 1 to 8.

10. a focusing lens frame for holding a focusing lens that moves in the optical axis direction during focusing; a fourth drive unit that drives the focusing lens frame in the optical axis direction; a second guide bar that guides the focusing lens frame in the optical axis direction; Equipped with the focusing lens frame has a second engagement portion that engages with the second guide bar, when the focusing lens frame, the diaphragm portion, and the lens are closest to each other, the second engagement portion, the diaphragm portion, and the lens overlap in a radial direction of the lens barrel. The lens barrel according to claim 2 .

11. The first frame holds a lens. The lens barrel according to any one of claims 1 to 8.

12. a holding cylinder for holding the first driving unit and the fourth driving unit; The lens barrel according to claim 10.

13. A lens mount that is detachable from the imaging device is provided. The lens barrel according to any one of claims 1 to 8, 10 and 12.

14. An imaging device comprising the lens barrel according to any one of claims 1 to 8, 10 and 12.