JP2022150116A - Diaphragm unit and lens barrel - Google Patents

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

It relates to an aperture unit and a lens barrel.

A lens barrel is provided with an aperture unit (see Patent Document 1, for example). There is a demand for improvement in aperture accuracy of aperture units.

JP-A-4-128727

According to the first aspect, 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 each of the first protrusions, and a second opening member having a plurality of holes engaging each of the second projections; and a biasing portion biasing the first projections against the grooves engaging the first projections. , provided.

According to a second aspect, the lens barrel includes the aperture unit.

It should be noted that the configurations of the embodiments described later may be modified as appropriate, and at least a part of them may be replaced with other components. Furthermore, constituent elements whose arrangement is not particularly limited are not limited to the arrangement disclosed in the embodiments, and can be arranged at positions where their functions can be achieved.

FIG. 1 is a diagram showing a camera including a lens barrel and a camera body according to one embodiment. FIG. 2 is an exploded perspective view of the diaphragm unit according to one embodiment, viewed from the camera body side. FIG. 3 is an exploded perspective view of the diaphragm unit according to one embodiment, viewed from the subject side. 4A is a plan view of the cam plate viewed from the camera body side, and FIG. 4B is a plan view of the cam plate viewed from the subject side. 5A is a perspective view of the biasing portion, FIG. 5B is a perspective view for explaining how the biasing portion is attached to the cam plate, and FIG. FIG. 5 is a plan view showing a state in which the biasing portion is attached to the cam plate; FIG. 6(A) is a diagram for explaining the relationship between the cam groove, the biasing portion, and the cam follower of the diaphragm blade in the small aperture state, and FIG. 6(B) is the cam groove in the open state, FIG. 5 is a diagram for explaining the relationship between a biasing portion and a cam follower of a diaphragm blade;

Hereinafter, a lens barrel according to one embodiment will be described with reference to the drawings. In the drawings shown below, an XYZ orthogonal coordinate system is appropriately provided for easy explanation and understanding. In this coordinate system, the +X direction is the direction from the subject toward the camera body 10 at the camera position (hereinafter referred to as normal position) when the photographer takes a landscape image with the optical axis OA horizontal. In addition, the direction toward the right side when viewed from the camera body 10 side in the normal position is defined as the +Y direction. Also, the upward direction in the normal position is the +Z direction. Note that the shapes, lengths, thicknesses, and other dimensions of the parts shown in the embodiments do not necessarily correspond to the real thing, and parts that are not necessary for explanation are omitted or simplified as appropriate.

FIG. 1 is a schematic diagram of a camera 1 including a lens barrel 20 and a camera body 10 according to this embodiment. The camera 1 includes a camera body 10 and a lens barrel 20 detachable from the camera body 10. - 特許庁Note that the lens barrel 20 and the camera body 10 may be integrated.

The lens barrel 20 includes lenses 21 and 22 as optical members that refract incident subject light to form a subject image on the output side, and an aperture unit 30 that adjusts the aperture. Although the lenses 21 and 22 are drawn as one lens in FIG. 1, the lenses 21 and 22 may be a lens group including a plurality of lenses. Also, the lens barrel 20 may have only one of the lenses 21 and 22 .

The camera body 10 has an imaging element 12 that takes an object image formed by a lens 21 and converts it into an electric signal.

Next, the configuration of the diaphragm unit 30 in this embodiment will be described. FIG. 2 is an exploded perspective view of the diaphragm unit 30 according to one embodiment viewed from the camera body side, and FIG. 3 is an exploded perspective view of the diaphragm unit 30 viewed from the object side.

The diaphragm unit 30 is an iris diaphragm device, and as shown in FIGS. biasing portion 35 (only one is shown in FIG. 2) and a stepping motor 36.

The opening member 31 is an annular member and has a fitting opening 311 in the center. A stepping motor 36 is attached to the +X side of the opening member 31 .

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 . Further, the rotating member 32 is formed with holes 323 that are the same in number as the aperture blades 33 . A support portion 331 for the diaphragm blade 33 , which will be described later, is inserted into each hole 323 .

A support portion 331 is provided on the +X side of the plurality of aperture blades 33, and a cam follower 332 is provided on the -X side. The support portion 331 is inserted into the hole 323 provided in the rotating member 32 , and the cam follower 332 is inserted into the cam groove 341 provided in the cam plate 34 .

The cam plate 34 is an annular member having an opening in the center, and is formed with the same number of cam grooves 341 as the diaphragm blades 33 . As described above, the cam follower 332 of the aperture blade 33 is inserted into the cam groove 341 . The cam groove 341 may be a through groove that penetrates the cam plate 34 or a groove that does not penetrate the cam plate 34 .

When an instruction to change the F-number is given from the camera body 10, the stepping motor 36 is rotationally driven, and the rotating member 32 having the segment gear 322 that meshes with the pinion gear 361 attached to the rotating shaft of the stepping motor 36 rotates. . Since the supporting portion 331 of the aperture blade 33 is inserted into the hole 323 formed in the rotary member 32, when the rotary member 32 rotates around the optical axis OA, the aperture blade 33 also rotates around the optical axis OA. Since the cam follower 332 of the aperture blade 33 is inserted into the cam groove 341 of the cam plate 34 , the cam follower 332 of the aperture blade 33 rotates along the cam groove 341 with the support portion 331 as a fulcrum. As a result, the aperture of the iris diaphragm (diaphragm aperture) 37 (see FIG. 1) can be adjusted by the plurality of diaphragm blades 33 .

Next, the configuration of the cam plate 34 will be described in more detail. 4A is a plan view of the cam plate 34 viewed from the camera body 10 side, and FIG. 4B is a plan view of the cam plate 34 viewed from the object side.

As shown in FIG. 4A, the same number of cam grooves 341 as the number of aperture blades 33 are formed on the +X side of the cam plate 34 . In this embodiment, the cam groove 341 is linear, but may be curved.

The cam groove 341 has a pair of opposing walls 341a and 341b. In this embodiment, the cam follower 332 of the aperture 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. Here, a clearance (gap) is provided between the cam groove 341 and the cam follower 332 of the diaphragm blade 33 in order to cope with changes in temperature and humidity. This clearance causes backlash between the cam groove 341 and the aperture blade 33 . Therefore, the diaphragm unit 30 according to the present embodiment includes the biasing portion 35 that biases the cam follower 332 against the wall 341a of the cam groove 341 in order to suppress the backlash.

FIG. 5A is a perspective view showing an example of the biasing portion 35. FIG. 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 .

In this embodiment, the biasing portion 35 is attached to the cam plate 34 . FIG. 5B is a perspective view for explaining how the biasing portion 35 is attached to the cam plate 34. FIG. As shown in FIG. 5B, the coil portion 351 of the urging portion 35 is engaged with the coil engaging portion 343 formed on the -X side of the cam plate 34, and the first arm 352 is engaged with the cam plate 34. and a part thereof is arranged on the +X side. The second arm 353 is locked by an arm locking portion 344 formed on the −X side of the cam plate 34 . That is, a portion of the biasing portion 35 (a portion of the first arm 352) is arranged between the cam plate 34 and the aperture blade 33, and the other portion of the biasing portion 35 (a second arm 353) is , on the opposite side (−X side) of the cam plate 34 from the diaphragm blade 33 .

FIG. 5(C) is a plan view showing a state where the biasing portion 35 is attached to the cam plate 34. FIG. As shown in FIG. 5C, the first arm 352 of the biasing portion 35 attached to the cam plate 34 is substantially 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 biasing portion 35 is attached in this way. When inserting the cam follower 332 into the cam groove 341, a jig or the like is used to flip up the first arm 352 as indicated by an arrow A11. As a result, a space is created between the wall 341a and the first arm 352 that is flipped up, so that the cam follower 332 of the aperture blade 33 can be easily inserted into the space. After inserting the cam follower 332 , the first arm 352 of the biasing section 35 can bias the cam follower 332 by returning the first arm 352 to its original position. By doing so, in the present embodiment, the cam followers 332 of the assembled diaphragm blades 33 can be inserted at once into the plurality of cam grooves 341 of the cam plate 34 to which the urging portion 35 is attached. 30 is easy to assemble.

Further, when all of the urging portions 35 are provided between the cam plate 34 and the aperture blades 33, the aperture blades 33 may be twisted because a load is directly applied to the aperture blades 33. On the other hand, when the urging portion 35 is arranged as in the present embodiment, the urging portion 35 pushes the cam follower 332, so that the possibility of the diaphragm blades 33 being twisted can be reduced. Since the cam follower 332 has higher rigidity than the diaphragm blade 33, the cam follower 332 hardly deforms.

Further, when all of the urging portions 35 are provided between the cam plate 34 and the aperture blades 33, in order to bring the first arm 352 into contact with the cam follower 332 and lock the second arm 353, the It is necessary to make the cam plate 34 thicker than in the case of the form. Therefore, a part of the first arm 352 is arranged between the cam plate 34 and the aperture blade 33, and the second arm 353 is arranged on the opposite side (-X side) of the aperture blade 33 of the cam plate 34. Therefore, the cam plate 34 can be made thinner than when all the urging portions 35 are provided between the cam plate 34 and the diaphragm blades 33, and the weight of the cam plate 34 and the diaphragm unit 30 can be reduced.

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 assembled diaphragm unit 30 will be described.

6A and 6B are diagrams for explaining the relationship between the cam groove 341, the biasing portion 35, and the cam follower 332. FIG. 6A shows a small aperture state in which the aperture 37 formed by the plurality of aperture blades 33 is the smallest, and FIG. 6B shows an open state in which the aperture 37 formed by the plurality of aperture blades 33 is the largest. indicates

As shown in FIGS. 6A and 6B, the first arm 352 (biasing portion 35) biases the cam follower 332 of the aperture blade 33 against the engaged cam groove 341. . Specifically, the first arm 352 biases the cam follower 332 against the wall 341a of the cam groove 341 (see arrows A1 and A2). More specifically, the first arm 352 biases the cam follower 332 of the aperture blade 33 against the wall 341a of the cam groove 341 in a direction substantially orthogonal to the wall 341a.

Thereby, backlash between the cam groove 341 and the cam follower 332 can be suppressed. Further, since the first arm 352 presses the cam follower 332 against the wall 341a of the cam groove 341, movement of the aperture blade 33 from the stop position can be suppressed. Therefore, aperture accuracy can be improved. 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 rotates the diaphragm blade 33. Working in the direction is suppressed, and it is possible to suppress the stepping motor 36 from being subjected to an excessive load.

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 cam follower 332 is biased between the position of the cam follower 332 in the small aperture state (small aperture position) and the position of the cam follower 332 in the open state (open position). As a result, play between the cam groove 341 and the cam follower 332 can be suppressed while the cam follower 332 is moving along the wall 341 a of the cam groove 341 .

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

When the diaphragm aperture 37 becomes smaller, the tips of the plurality of diaphragm blades 33 overlap and rise (see FIG. 3, for example). As a result, each diaphragm blade 33 biases the other diaphragm blades 33 overlapping itself in the direction in which the diaphragm opening 37 becomes larger. Therefore, as the aperture 37 becomes smaller, the stepping motor 36 receives a force (reaction force) from the aperture blades 33 in a direction opposite to the direction in which the aperture 37 is made smaller, increasing the load on the stepping motor 36 . By setting the small aperture position of the cam follower 332 closer to the coil part 351 than the open position of the cam follower 332, the closer to the small aperture position, the larger the biasing force of the biasing part 35, so the aperture opening 37 is made smaller. In some cases, the reaction force transmitted to the stepping motor 36 can be reduced, and the load applied to the stepping motor 36 can be reduced.

As described above in detail, according to the present embodiment, the diaphragm unit 30 includes a plurality of diaphragm blades 33 each having a cam follower 332 and a support portion 331 and a plurality of aperture blades 33 engaging with each of the cam followers 332 . , the rotary member 32 having a plurality of holes 323 that engage with each of the support portions 331, and the cam follower 332 are biased against the cam groove 341 that engages with the cam follower 332. and an urging portion 35 . This suppresses looseness between the cam follower 332 and the cam groove 341 .

In addition, in this embodiment, the cam groove 341 has a wall 341 a that guides the cam follower 332 , and the biasing portion 35 biases the cam follower 332 against the wall 341 a of the cam groove 341 . Also, the biasing portion 35 biases 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. 6A and 6B). As a result, it is possible to suppress an increase in the load on the stepping motor 36 due to the reaction force that the diaphragm blades 33 receive from the wall 341 a when the biasing portion 35 biases the cam follower 332 .

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 there is no urging portion 35, or if the urging portion 35 urges the cam follower 332 toward the wall 341b, in the small aperture state, the aperture blades 33 receive the reaction force and warp up, and the aperture diameter increases. Accuracy deteriorates. On the other hand, in the present embodiment, the cam follower 332 is urged toward the wall 341a near the optical axis OA by the urging portion 35, so warping is suppressed and the accuracy of the aperture diameter in the small aperture state can be improved.

Further, in the present 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. As a result, play between the cam groove 341 and the cam follower 332 can be suppressed while the cam follower 332 is moving along the cam groove 341 .

Further, in the present 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 positioned in a small aperture state in which the diaphragm opening 37 formed by the plurality of diaphragm blades 33 is the smallest. As described above, the smaller the diaphragm opening 37, the greater the force that each diaphragm blade 33 receives from the other diaphragm blades 33 in the direction of enlarging the diaphragm 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 cam follower 332 moves from the aperture blades 33 at the small aperture position to the stepping motor. The reaction force transmitted to 36 can be reduced, and the load applied to the stepping motor 36 can be reduced.

Also, in this embodiment, the biasing portion 35 is a torsion coil spring, and the first arm 352 that contacts the cam follower 332 is substantially parallel to the cam groove 341 . As a result, the cam follower 332 can be biased in a direction substantially perpendicular to the wall 341a of the cam groove 341 (see arrows A1 and A2 in FIGS. 6A and 6B).

Further, in this embodiment, the first arm 352 of the biasing portion 35 is arranged between the diaphragm blades 33 and the cam plate 34 , and the second arm 353 of the biasing portion 35 is positioned between the diaphragm blades 33 of the cam plate 34 . placed on the opposite side of the As a result, the cam plate 34 can be made thinner than when all the urging portions 35 are provided between the cam plate 34 and the diaphragm blades 33, and the weight of the cam plate 34 and the diaphragm unit 30 can be reduced.

In the above embodiment, a torsion coil spring is used as the biasing portion 35, but the present invention is not limited to this. For example, any spring capable of biasing the cam follower 332 toward the wall 341a , leaf springs, compression springs, or the like may be used.

In the above embodiment, the biasing portion 35 biases the cam follower 332 toward the wall 341a, but the cam follower 332 may be biased toward the wall 341b. In this case, the wall 341 b serves as a wall that guides the cam follower 332 .

In the above embodiment, the biasing portion 35 is attached to the cam plate 34. However, if the cam follower 332 can be biased toward the wall 341a or 341b of the cam groove 341, the biasing portion 35 can be attached to the rotating member 32. may be attached to the

The embodiments described above are examples of preferred implementations. However, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention, and arbitrary constituent elements may be combined.

1 camera 20 lens barrel 30 aperture unit 32 rotating member 33 aperture blade 34 cam plate 35 biasing portion 37 aperture opening 331 support portion 332 cam follower 341 cam grooves 341a, 341b wall 352 first arm

Claims (12)

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 opening member having a plurality of holes that engage with each of the second protrusions;
a biasing portion that biases the first protrusion against the groove that engages with the first protrusion;
Aperture unit. The groove has a wall that guides the first protrusion,
the biasing portion biases the first projection against the wall of the groove;
A diaphragm unit according to claim 1. The groove has a wall facing the wall that guides the first projection,
The wall that guides the first protrusion is closer to the optical axis than the opposing wall,
A diaphragm unit according to claim 2. The biasing portion biases the first protrusion in a direction substantially perpendicular to the wall of the groove,
The diaphragm unit according to claim 2 or 3. The biasing portion biases the first protrusion from one end to the other end of the range in which the first protrusion moves,
The diaphragm unit according to any one of claims 1 to 4. 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;
A diaphragm unit according to claim 5 . The first protrusion is positioned at the one end in a small aperture state in which the diaphragm opening formed by the plurality of diaphragm blades is the smallest,
The diaphragm unit according to claim 5 or 6. at least a portion of the biasing portion is substantially parallel to the groove;
The diaphragm unit according to any one of claims 1 to 7. The biasing portion is a torsion coil spring,
an arm portion of the torsion coil spring that contacts the first projection is substantially parallel to the groove,
The diaphragm unit according to any one of claims 1 to 8. the groove is linear;
The diaphragm unit according to any one of claims 1 to 9. A part of the biasing portion is arranged between the diaphragm blade and the first opening member,
Another part of the biasing portion is arranged on the opposite side of the first opening member from the diaphragm blade,
The diaphragm unit according to any one of claims 1 to 10. A lens barrel comprising the diaphragm unit according to any one of claims 1 to 11.

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