Aperture unit and lens barrel

Abstract

To provide a diaphragm unit and a lens barrel which improve diaphragm accuracy.SOLUTION: A diaphragm unit includes: a plurality of diaphragm blades having each of first protrusions and second protrusions; a first opening member having a plurality of grooves for engaging with each of the first protrusions; a second opening member having a plurality of holes for engaging with each of the second protrusions; and energizing parts for energizing the first protrusions relative to the grooves for engaging with the first protrusions.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] A lens barrel is provided with an aperture unit (see, for example, Patent Document 1). There is a demand for improved aperture accuracy of the aperture unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-128727 Summary of the Invention

[0004] According to a first aspect, a lens is provided with a plurality of aperture blades each having a first protrusion and a second protrusion, a first aperture member having a plurality of grooves that engage with each of the first protrusions, a second aperture member having a plurality of holes that engage with each of the second protrusions, and a biasing portion that biases the first protrusion against the groove that engages with the first protrusion. A part of the urging portion is disposed between the diaphragm blade and the first opening member, and another part of the urging portion is disposed on the opposite side of the first opening member from the diaphragm blade. .

[0005] According to a second aspect, a lens barrel includes the above-described aperture unit.

[0006] The configurations of the embodiments described below may be appropriately improved, and at least a part of them may be replaced with other components. Furthermore, components that are not particularly limited in terms of their location may be located in any location that achieves their function, not limited to the location disclosed in the embodiments. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a camera including a lens barrel and a camera body according to an embodiment. [Diagram 2]FIG. 2 is an exploded perspective view of the aperture unit according to one embodiment, as viewed from the camera body side. [Diagram 3] FIG. 3 is an exploded perspective view of the aperture unit according to the embodiment, as viewed from the subject side. [Figure 4] FIG. 4(A) is a plan view of the cam plate as viewed from the camera body side, and FIG. 4(B) is a plan view of the cam plate as viewed from the subject side. [Diagram 5] FIG. 5(A) is an oblique view of the urging portion, FIG. 5(B) is an oblique view for explaining the attachment of the urging portion to the cam plate, and FIG. 5(C) is a plan view showing the state in which the urging portion is attached to the cam plate. [Figure 6] FIG. 6(A) is a diagram for explaining the relationship between the cam groove, the biasing portion, and the cam follower of the aperture blade in the small aperture state, and FIG. 6(B) is a diagram for explaining the relationship between the cam groove, the biasing portion, and the cam follower of the aperture blade in the open state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a lens barrel according to an embodiment will be described with reference to the drawings. In order to facilitate explanation and understanding, an XYZ Cartesian coordinate system is appropriately provided in the drawings shown below. In this coordinate system, the direction from the subject toward the camera body 10 at the camera position (hereinafter referred to as the normal position) when the photographer takes a landscape image with the optical axis OA horizontal is defined as the +X direction. In addition, the direction toward the right side as viewed from the camera body 10 at the normal position is defined as the +Y direction. In addition, the direction toward the upper side at the normal position is defined as the +Z direction. Note that the scales of the shapes, lengths, thicknesses, etc. of the parts shown in the embodiment do not necessarily match the actual ones, and parts not necessary for explanation are appropriately omitted or simplified.

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

[0010] Lens barrel 20 includes lenses 21 and 22 as optical members that refract incident subject light to form a subject image on the exit side, and aperture unit 30 that adjusts the aperture. Although lenses 21 and 22 are depicted as single lenses in Fig. 1, lenses 21 and 22 may be a lens group including multiple lenses. Furthermore, lens barrel 20 may have only one of lenses 21 and 22.

[0011] The camera body 10 includes an image sensor 12 that captures a subject image formed by a lens 21 and converts it into an electrical signal.

[0012] Next, a configuration of the aperture unit 30 in this embodiment will be described. Fig. 2 is an exploded perspective view of the aperture unit 30 according to one embodiment as viewed from the camera body side, and Fig. 3 is an exploded perspective view of the aperture unit 30 as viewed from the subject side.

[0013] The aperture unit 30 is an aperture device, and as shown in Figures 2 and 3, includes an aperture member 31, a rotating member 32, a plurality of aperture blades 33 (only one is shown in Figure 2), a cam plate 34, a plurality of urging portions 35 (only one is shown in Figure 2), and a stepping motor 36.

[0014] The opening member 31 is an annular member, and has a fitting opening 311 in the center. In addition, a stepping motor 36 is attached to the +X side of the opening member 31.

[0015] The rotating member 32 is an annular member having an opening in the center, and has an annular protrusion 321 in the center that fits into the fitting opening 311 of the opening member 31. A segment gear 322 is formed on the outer edge of the rotating member 32, and meshes with a pinion gear 361 attached to the rotating shaft of the stepping motor 36. The rotating member 32 is also formed with holes 323 in the same number as the number of the diaphragm blades 33. A support portion 331 of the diaphragm blade 33, which will be described later, is inserted into each hole 323.

[0016] Support parts 331 are provided on the +X side of the multiple diaphragm blades 33, and cam followers 332 are provided on the -X side. The support parts 331 are inserted into holes 323 provided in the rotating member 32, and the cam followers 332 are inserted into cam grooves 341 provided in the cam plate .

[0017] The cam plate 34 is an annular member having an opening in the center, and has cam grooves 341 formed therein, the same number as the number of diaphragm blades 33. As described above, the cam followers 332 of the diaphragm blades 33 are inserted into the cam grooves 341. The cam grooves 341 may be through grooves that pass through the cam plate 34, or may be grooves that do not pass through the cam plate 34.

[0018] When an instruction to change the F-number is given from the camera body 10, the stepping motor 36 is rotated, and the rotating member 32 having the segment gear 322 meshing with the pinion gear 361 attached to the rotating shaft of the stepping motor 36 rotates. Since the support portion 331 of the diaphragm blade 33 is inserted into the hole 323 formed in the rotating member 32, when the rotating member 32 rotates around the optical axis OA, the diaphragm blade 33 also rotates around the optical axis OA. Since the cam follower 332 of the diaphragm blade 33 is inserted into the cam groove 341 of the cam plate 34, the cam follower 332 of the diaphragm blade 33 rotates along the cam groove 341 with the support portion 331 as a fulcrum. In this way, the size of the aperture (diaphragm opening) 37 (see FIG. 1) of the iris diaphragm can be adjusted by the multiple diaphragm blades 33.

[0019] Next, a more detailed description will be given of the configuration of the cam plate 34. Fig. 4(A) is a plan view of the cam plate 34 as viewed from the camera body 10 side, and Fig. 4(B) is a plan view of the cam plate 34 as viewed from the subject side.

[0020] 4A, cam grooves 341 are formed on the +X side of the cam plate 34, the number of which is the same as the number of the diaphragm blades 33. In this embodiment, the cam grooves 341 are linear, but may be curved.

[0021] The cam groove 341 has a pair of opposing walls 341a and 341b. In this embodiment, the cam follower 332 of the diaphragm blade 33 inserted into the cam groove 341 moves while being guided by the wall 341a. The wall 341a is closer to the optical axis OA than the wall 341b. A clearance (gap) is provided between the cam groove 341 and the cam follower 332 of the diaphragm blade 33 to accommodate changes in temperature and humidity. The clearance causes backlash between the cam groove 341 and the diaphragm blade 33. Therefore, the diaphragm unit 30 according to this embodiment is provided with a biasing unit 35 that biases the cam follower 332 against the wall 341a of the cam groove 341 in order to suppress the backlash.

[0022] 5(A) is a perspective view showing an example of the biasing portion 35. In this embodiment, the biasing portion 35 is a torsion coil spring having a coil portion 351, a first arm 352, and a second arm 353.

[0023] In this embodiment, the urging unit 35 is attached to the cam plate 34. FIG. 5B is a perspective view for explaining the attachment of the urging unit 35 to the cam plate 34. As shown in FIG. 5B, the coil portion 351 of the urging unit 35 is engaged with the coil engagement portion 343 formed on the -X side of the cam plate 34, and the first arm 352 is passed through a through hole 342 penetrating the cam plate 34, and a part of the first arm 352 is disposed on the +X side. The second arm 353 is engaged with the arm engagement portion 344 formed on the -X side of the cam plate 34. That is, a part of the urging unit 35 (a part of the first arm 352) is disposed between the cam plate 34 and the diaphragm blade 33, and the other part of the urging unit 35 (the second arm 353) is disposed on the opposite side (-X side) of the cam plate 34 to the diaphragm blade 33.

[0024] FIG. 5C is a plan view showing a state in which the urging unit 35 is attached to the cam plate 34. As shown in FIG. 5C, the first arm 352 of the urging unit 35 attached to the cam plate 34 is approximately parallel to the linear cam groove 341. The cam follower 332 of the assembled diaphragm blade 33 is inserted into the cam groove 341 of the cam plate 34 to which the urging unit 35 is attached in this manner. When inserting the cam follower 332 into the cam groove 341, the first arm 352 is flipped up as shown by the arrow A11 using a jig or the like. This creates a space between the wall 341a and the flipped up first arm 352, so that the cam follower 332 of the diaphragm blade 33 can be easily inserted into the space. Then, after the cam follower 332 is inserted, the flipped up first arm 352 is returned to its original position, so that the first arm 352 of the urging unit 35 can urge the cam follower 332. By doing this, in this embodiment, the cam followers 332 of the assembled aperture blades 33 can be inserted all at once into the multiple cam grooves 341 of the cam plate 34 to which the biasing portion 35 is attached, making it easy to assemble the aperture unit 30.

[0025] Furthermore, if all of the urging parts 35 are provided between the cam plate 34 and the diaphragm blade 33, a load is applied directly to the diaphragm blade 33, which may cause the diaphragm blade 33 to twist. On the other hand, if the urging parts 35 are arranged as in this embodiment, the urging parts 35 press the cam followers 332, which reduces the possibility of the diaphragm blade 33 twisting. The cam followers 332 have higher rigidity than the diaphragm blade 33, so the cam followers 332 are hardly deformed.

[0026] Furthermore, when all of the urging portions 35 are provided between the cam plate 34 and the aperture blade 33, in order to bring the first arm 352 into contact with the cam follower 332 and to lock the second arm 353, the cam plate 34 needs to be thicker than in the present embodiment. Therefore, by disposing a part of the first arm 352 between the cam plate 34 and the aperture blade 33 and disposing the second arm 353 on the opposite side (-X side) of the cam plate 34 to the aperture blade 33, the cam plate 34 can be made thinner than when all of the urging portions 35 are provided between the cam plate 34 and the aperture blade 33, and the cam plate 34 and therefore the aperture unit 30 can be made lighter.

[0027] Next, the relationship between the cam groove 341 of the cam plate 34, the biasing portion 35, and the cam follower 332 of the diaphragm blade 33 in the diaphragm unit 30 after assembly will be described.

[0028] 6(A) and 6(B) are diagrams for explaining the relationship between the cam groove 341, the biasing portion 35, and the cam follower 332. Fig. 6(A) shows a small aperture state in which the aperture opening 37 formed by the multiple aperture blades 33 is the smallest, and Fig. 6(B) shows an open state in which the aperture opening 37 formed by the multiple aperture blades 33 is the largest.

[0029] 6(A) and 6(B), the first arm 352 (urging portion 35) urges the cam follower 332 of the diaphragm blade 33 against the cam groove 341 in which it is engaged. Specifically, the first arm 352 urges the cam follower 332 against the wall 341a of the cam groove 341 (see arrows A1 and A2). More specifically, the first arm 352 urges the cam follower 332 of the diaphragm blade 33 against the wall 341a in a direction substantially perpendicular to the wall 341a of the cam groove 341.

[0030] This can suppress backlash between the cam groove 341 and the cam follower 332. In addition, since the first arm 352 presses the cam follower 332 against the wall 341a of the cam groove 341, the diaphragm blade 33 can be prevented from moving from the stop position. This can improve the diaphragm accuracy. Furthermore, since the first arm 352 biases the cam follower 332 of the diaphragm blade 33 in a direction substantially perpendicular to the wall 341a of the cam groove 341, the reaction force that the diaphragm blade 33 receives from the wall 341a is prevented from acting in a direction that rotates the diaphragm blade 33, and the generation of an extra load on the stepping motor 36 can be suppressed.

[0031] The first arm 352 of the biasing portion 35 biases the cam follower 332 between one end and the other end of the range R1 in which the cam follower 332 moves. More specifically, the first arm 352 biases the cam follower 332 between the position of the cam follower 332 in the small throttle state (small throttle position) and the position of the cam follower 332 in the open state (open position). This makes it possible to suppress rattling between the cam groove 341 and the cam follower 332 while the cam follower 332 moves along the wall 341a of the cam groove 341.

[0032] The biasing force of first arm 352 is stronger the closer to coil portion 351 and decreases the farther from coil portion 351. In this embodiment, the small throttle position of cam follower 332 is closer to coil portion 351 than the open position of cam follower 332. Therefore, the biasing force with which biasing portion 35 biases cam follower 332 at the small throttle position is greater than the biasing force with which biasing portion 35 biases cam follower 332 at the open position.

[0033] When the aperture opening 37 becomes smaller, the tips of the aperture blades 33 overlap and rise (see FIG. 3, for example). As a result, each aperture blade 33 urges the other aperture blades 33 overlapping with it in a direction in which the aperture opening 37 becomes larger. Therefore, the smaller the aperture opening 37 becomes, the more the stepping motor 36 receives a force (reaction force) from the aperture blades 33 in the opposite direction to the direction in which the aperture opening 37 becomes smaller, and the load on the stepping motor 36 increases. By placing the small aperture position of the cam follower 332 closer to the coil portion 351 than the open position of the cam follower 332, the closer to the small aperture position, the greater the urging force of the urging portion 35 becomes. Therefore, the reaction force transmitted to the stepping motor 36 when the aperture opening 37 is reduced can be reduced, and the load on the stepping motor 36 can be reduced.

[0034] As described above in detail, according to this embodiment, the aperture unit 30 includes a plurality of aperture blades 33 each having a cam follower 332 and a support portion 331, a cam plate 34 having a plurality of cam grooves 341 that engage with each of the cam followers 332, a rotating member 32 having a plurality of holes 323 that engage with each of the support portions 331, and a biasing portion 35 that biases the cam follower 332 against the cam groove 341 that engages with the cam follower 332. This suppresses rattle between the cam follower 332 and the cam groove 341.

[0035] In this embodiment, the cam groove 341 has a wall 341a that guides the cam follower 332, and the biasing unit 35 biases the cam follower 332 against the wall 341a of the cam groove 341. The biasing unit 35 biases the cam follower 332 in a direction (see arrows A1 and A2 in FIGS. 6A and 6B) that is substantially perpendicular to the wall 341a of the cam groove 341. This makes it possible to suppress an increase in the load on the stepping motor 36 due to a reaction force that the diaphragm blade 33 receives from the wall 341a as a result of the biasing unit 35 biasing the cam follower 332.

[0036] In this embodiment, the cam groove 341 has a wall 341b facing the wall 341a that guides the cam follower 332, and the wall 341a is closer to the optical axis OA than the wall 341b. If the biasing unit 35 is not present, or if the biasing unit 35 biases the cam follower 332 toward the wall 341b, in the small aperture state, the aperture blades 33 receive a reaction force and warp, deteriorating the accuracy of the aperture diameter. On the other hand, in this embodiment, the biasing unit 35 biases the cam follower 332 toward the wall 341a that is closer to the optical axis OA, so that warping is suppressed and the accuracy of the aperture diameter in the small aperture state can be improved.

[0037] In this embodiment, the biasing portion 35 biases the cam follower 332 from one end to the other end of the range in which the cam follower 332 moves. This makes it possible to suppress rattling between the cam groove 341 and the cam follower 332 while the cam follower 332 moves along the cam groove 341.

[0038] In this embodiment, the biasing force of the biasing portion 35 at one end of the range in which the cam follower 332 moves is greater than the biasing force of the biasing portion 35 at the other end. At one end of the range in which the cam follower 332 moves, the cam follower 332 is located in a small aperture state where the aperture opening 37 formed by the plurality of aperture blades 33 is smallest. As described above, the smaller the aperture opening 37, the greater the force that each aperture blade 33 receives from the other aperture blades 33 in the direction of enlarging the aperture opening 37, and the greater the load on the stepping motor 36. By increasing the biasing force of the biasing portion 35 at the small aperture position (one end of the range in which the cam follower 332 moves) where the cam follower 332 is located in the small aperture state, the reaction force transmitted from the aperture blade 33 in the small aperture position to the stepping motor 36 can be reduced, and the load on the stepping motor 36 can be reduced.

[0039] In this embodiment, the biasing portion 35 is a torsion coil spring, and the first arm 352 in contact with the cam follower 332 is substantially parallel to the cam groove 341. This makes it possible to bias the cam follower 332 in a direction substantially perpendicular to the wall 341a of the cam groove 341 (see arrows A1 and A2 in FIGS. 6(A) and 6(B)).

[0040] In this embodiment, the first arm 352 of the urging portion 35 is disposed between the diaphragm blade 33 and the cam plate 34, and the second arm 353 of the urging portion 35 is disposed on the side of the cam plate 34 opposite the diaphragm blade 33. This allows the cam plate 34 to be made thinner than when the entire urging portion 35 is provided between the cam plate 34 and the diaphragm blade 33, and the cam plate 34 and therefore the diaphragm unit 30 can be made lighter.

[0041] In the above embodiment, a torsion coil spring is used as the biasing portion 35, but this is not limited to this. For example, a leaf spring or a compression spring may be used as long as it is a spring capable of biasing the cam follower 332 toward the wall 341a.

[0042] In the above embodiment, the biasing portion 35 biases the cam follower 332 toward the wall 341a, but the biasing portion 35 may bias the cam follower 332 toward the wall 341b. In this case, the wall 341b serves as a wall for guiding the cam follower 332.

[0043] In addition, in the above embodiment, the urging portion 35 was attached to the cam plate 34, but the urging portion 35 may be attached to the rotating member 32 as long as it can urge the cam follower 332 toward the wall 341a or 341b of the cam groove 341.

[0044] The above-described embodiment is a preferred example, but is not limited thereto, and various modifications are possible without departing from the scope of the present invention, and any combination of components may be used. [Explanation of symbols]

[0045] 1 Camera 20 Lens barrel 30 Aperture unit 32 Rotating members 33 Aperture blades 34 Cam plate 35 Pressurizing section 37 Aperture 331 Support part 332 Cam Follower 341 Cam groove 341a,341b wall 352 First Arm

Claims

1. A plurality of aperture blades each having a first protrusion and a second protrusion; a first opening member having a plurality of grooves that engage with the first protrusions; a second opening member having a plurality of holes that engage with the second protrusions; a biasing portion that biases the first protrusion against the groove that engages with the first protrusion; Equipped with a portion of the urging portion is disposed between the diaphragm blade and the first opening member, Another part of the biasing portion is disposed on the opposite side of the first opening member from the aperture blade. Aperture unit.

2. the groove has a wall that guides the first protrusion, The biasing portion biases the first protrusion against the wall of the groove. The aperture unit according to claim 1 .

3. the groove has a wall facing a wall that guides the first protrusion, the wall that guides the first protrusion is closer to the optical axis than the opposing wall; The aperture unit according to claim 2.

4. The biasing portion biases the first protrusion in a direction substantially perpendicular to the wall of the groove. The aperture unit according to claim 2 or 3.

5. The biasing portion biases the first protrusion from one end to the other end of a range in which the first protrusion moves. The aperture unit according to any one of claims 1 to 4.

6. The biasing force of the biasing portion at the one end is greater than the biasing force of the biasing portion at the other end. The aperture unit according to claim 5.

7. the first protrusion is located at the one end in a small aperture state in which the aperture opening formed by the plurality of aperture blades is smallest; The aperture unit according to claim 5 or 6.

8. At least a portion of the biasing portion is substantially parallel to the groove. The aperture unit according to any one of claims 1 to 7.

9. The biasing portion is a torsion coil spring, The arm portion of the torsion coil spring that contacts the first protrusion is substantially parallel to the groove. The aperture unit according to any one of claims 1 to 8.

10. The groove is linear. The aperture unit according to any one of claims 1 to 9.

11. A lens barrel comprising the aperture unit according to any one of claims 1 to 10.

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