JP2020027231A - Luminous power adjusting device and optical apparatus - Google Patents

Abstract

To provide a compact and high accuracy luminous power adjusting device that forms a circular light passage opening from an open state to a small aperture diameter.SOLUTION: A luminous power adjusting device comprises: a base member having a light passage opening; a first aperture blade group composed of a plurality of first aperture blades coming in and out of the light passage opening; and a second aperture blade group composed of a plurality of second aperture blades coming in and out of the light passage opening. In the process of a change from aperture full open to intermediate aperture, an aperture opening is formed by only the first aperture blade group, or by only the second aperture blade group, or by collaboration of the first and second aperture blade groups. In the process of a change from intermediate aperture to minimum aperture, an aperture opening is formed by only one of the first and second aperture blade groups, with the other aperture blade group moving in a direction in which the opening opens.SELECTED DRAWING: Figure 6

Description

  The present invention relates to, for example, a light amount adjusting device such as an aperture device and an optical apparatus including the same.

  It is preferable that the shape of the aperture as a light passage aperture formed in the aperture device is as close as possible to a circle. In order to form an aperture close to a circle, three or more aperture blades (light quantity adjusting blades) are required. Often used. Further, a plurality of diaphragm blades are rotated by a drive ring that is rotatable around a fixed opening formed in the base member (opening forming member), thereby forming a nearly polygonal diaphragm opening.

  Here, Patent Literature 1 discloses a diaphragm device that sequentially uses a plurality of blade groups so that the shape of the diaphragm opening approaches a circle.

JP-A-2017-58679 JP 2012-123299 A

  However, in the diaphragm device disclosed in Patent Document 1, in order to prevent light from leaking from the cam groove formed in the diaphragm blade, it is necessary to cover the cam groove with another blade, and the diaphragm blade needs to be covered with another blade. In order to prevent the aperture blade group from colliding with the aperture blade group, there is a problem that the number of aperture blade groups must be increased to three or four when the light amount adjustment range from the maximum aperture to the minimum aperture is wide.

  Further, in the diaphragm device disclosed in Patent Document 2, as the number of blades is increased in order to make the shape of the diaphragm opening closer to a circle, the knitting load of the blades increases, and the power consumption for driving increases. There were challenges. Further, when the diaphragm blade group is divided into two, it is necessary to arrange the diaphragm blade groups so as not to interfere with each other, and there is a problem that the position of the diaphragm aperture is separated in the optical axis direction.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a small and highly accurate light amount adjusting device that forms a highly circular light passage opening from an open state to a small aperture diameter.

  A light amount adjusting device according to the present invention is a first diaphragm blade including a base member having a light passage opening, a base member having a light passage opening, and a plurality of first diaphragm blades entering and exiting the light passage opening. And a second group of second diaphragm blades including a plurality of second diaphragm blades that enter and exit the light passage opening. In the process of changing from a fully opened diaphragm to an intermediate diaphragm, the first diaphragm blade group is used. Only, or only the second aperture blade group, or the aperture aperture formed by cooperation of the first and second aperture blade groups, and in the process of changing from the intermediate aperture to the minimum aperture, The aperture opening is formed by only one of the second aperture blade groups, and the other aperture blade group moves in a direction in which the aperture opens.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to form a light-passing opening with high circularity from an open state to a small aperture diameter, and to provide a small and highly accurate light amount adjusting device.

FIG. 1 is an exploded perspective view of a diaphragm device that is a first embodiment of a light amount adjusting device according to the present invention. The figure which looked at FIG. 1A from the upside down direction. FIG. 2 is a perspective view of the diaphragm device according to the first embodiment. FIG. 4 is a diagram illustrating aperture blades of a first aperture blade group. The figure which shows the aperture blade of a 2nd aperture blade group. FIG. 4 is a diagram showing a light passage opening of the diaphragm device. FIG. 3 is an enlarged view of a light passage opening of the diaphragm device. FIG. 5 is a diagram illustrating the movement of a first diaphragm blade group. FIG. 7 is a diagram illustrating the movement of a second diaphragm blade group. FIG. 5 is a diagram illustrating a relationship between a first diaphragm blade group and a second diaphragm blade. The figure which extracted and shown FIG. 9 (C). FIG. 4 is a projection view of a first drive ring and a second drive ring. FIG. 4 is an exploded perspective view of a modification of the diaphragm device according to the first embodiment. FIG. 12B is a view of FIG. FIG. 10 is a side sectional view of a diaphragm device according to a modification. FIG. 6 is an exploded perspective view of a diaphragm device which is a second embodiment of the light amount adjusting device of the present invention. FIG. 4 is a diagram showing the movement of a group of aperture blades. FIG. 5 is an enlarged view showing the movement of the diaphragm blade group. FIG. 2 is a schematic diagram of an optical apparatus equipped with any one of the aperture devices according to the first to third embodiments.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First embodiment>
FIG. 1A is an exploded perspective view of a diaphragm device 100 according to a first embodiment of the light amount adjusting device of the present invention. FIG. 1B is an exploded perspective view of the diaphragm device 100 as viewed from a direction opposite to that of FIG. 1A. FIG. 2 is a perspective view of the assembled state of the aperture device 100 as viewed from the front and back.

  1A and 1B, a base member 2 (opening forming member) serving as a base of the diaphragm device 100 has an opening 2a at the center corresponding to the optical axis O of the lens to allow light to pass therethrough. Outside the opening 2a, an inner engaging portion 2k and engaging holes 2b and 2c are formed. The plurality of engagement holes 2b and 2c are alternately arranged around the opening 2a.

  The base member 2 is generally made by molding a resin. A drive unit 1 using, for example, a stepping motor, a galvanometer, or the like is attached to the base member 2, and a pinion gear 3 is attached to a rotation shaft of the drive unit 1.

  A first drive ring 4 for driving a first diaphragm blade group 50 described later has an outer engaging portion 4k, a cam groove 4e, and a driven portion 4d. The first drive ring 4 is generally formed by molding a resin, but may be formed by, for example, pressing a resin film (such as a PET sheet material).

  The outer engagement portion 4k of the first drive ring 4 is rotatably engaged with the inner engagement portion 2k of the base member 2. The inner engaging portion 2k of the base member 2 may have a continuous circular shape, but is constituted by a plurality of convex portions and is configured to engage with the outer engaging portion 4k of the first drive ring 4. May be.

  In the present embodiment, the first drive ring 4 is engaged with the inside of the inner engagement portion 2k of the base member 2, but the first drive ring 4 is formed with an inner engagement portion, An outer engaging portion may be formed on the base member 2 so that the first drive ring 4 is engaged with the outer side of the outer engaging portion of the base member 2.

  The first drive ring 4 has a gear portion that is a driven portion 4d. The driven portion 4d meshes with the pinion gear 3, and the rotational force generated by the driving portion 1 is transmitted from the pinion gear 3 to the driven portion 4d, and the first drive ring 4 is rotated.

  A second drive ring 7 for driving a second group of aperture blades 60 described later has an outer engagement portion 7k, a cam groove 7f, and a driven portion 7d. The second drive ring 7 is generally formed by molding a resin, but may be formed by, for example, pressing a resin film (such as a PET sheet material).

  The outer engagement portion 7k of the second drive ring 7 is rotatably engaged with an inner engagement portion 8k of the cover member 8 described later. The inner engaging portion 8k of the cover member 8 may have a continuous circular shape, but is constituted by a plurality of convex portions, and is configured to engage with the outer engaging portion 7k of the second drive ring 7. May be.

  In the present embodiment, the second drive ring 7 is engaged with the inside of the inner engagement portion 8k of the cover member 8, but the second drive ring 7 is formed with an inner engagement portion, An outer engaging portion may be formed on the cover member 8, and the second drive ring 7 may be engaged outside the outer engaging portion of the cover member 8.

  The second drive ring 7 has a gear portion that is a driven portion 7d. The driven portion 7d meshes with the pinion gear 3, and the rotational force generated by the driving portion 1 is transmitted from the pinion gear 3 to the driven portion 7d, and the second drive ring 7 is rotated.

  In the present embodiment, the first and second drive rings 4 and 7 are both driven with one drive unit 1. Although one drive source is easier to synchronize the first and second drive rings 4 and 7, a drive unit may be separately provided for each of the first and second drive rings 4 and 7. In the present embodiment, the rotation directions of the first and second drive rings are set to the same direction, but may be set to opposite directions.

  Note that the rotation direction in which the blade group that engages with each drive ring rotates can be appropriately adjusted according to the direction in which the cam groove is formed, but in the present embodiment, like the rotation direction of the drive ring, The first blade group 50 and the second blade group 60 are configured to have the same rotation direction. By configuring the plurality of blade groups to have the same rotation direction, it is possible to easily prevent the aperture blades 5 and the aperture blades 6 constituting the respective blade groups from colliding with each other. However, this does not prevent the rotation direction of the first blade group 50 and the second blade group 60 from being opposite to each other, so that the stop blade 5 and the stop blade 6 do not collide with each other. I just need.

  Above the first drive ring 4 (upper side in FIG. 1), a first diaphragm blade group 50 is arranged. The first diaphragm blade group 50 includes a plurality of diaphragm blades 5. In the present embodiment, the first diaphragm blade group 50 is composed of nine diaphragm blades 5. However, the number of diaphragm blades may be any number as long as the diaphragm blades are composed of a plurality of diaphragm blades. FIG. 3 is a diagram showing the shape of one diaphragm blade 5. The diaphragm blade 5 has a diaphragm opening forming edge 5r, a tip 5g, an engaging pin (rotation center engaging portion) 5b as an engaging portion, and a cam pin 5e as a driven portion.

  Above the first diaphragm blade group 50, a second diaphragm blade group 60 is arranged. The second diaphragm blade group 60 is constituted by a plurality of diaphragm blades 6. In the present embodiment, the second diaphragm blade group 60 is constituted by nine diaphragm blades 6. However, the number of diaphragm blades may be any number as long as the diaphragm blades are composed of a plurality of diaphragm blades. FIG. 4 is a diagram showing the shape of one diaphragm blade 6. The aperture blade 6 has an aperture opening forming edge 6r, a tip 6g, an engagement pin (rotation center engagement portion) 6c as an engagement portion, and a cam pin 6f as a driven portion.

  The aperture blade 5 and the aperture blade 6 are formed by, for example, resin molding. Further, for example, a metal sheet or a resin pin may be formed by press-welding, bonding, or integrally forming a metal sheet or a resin pin on a PET sheet material or the like. Further, it is desirable that the aperture blades be subjected to a light-shielding process, an anti-reflection process, a sliding process, and the like.

  Above the second drive ring 7, a cover member 8 having an opening 8a formed in the center is arranged. In the space formed by the base member 2 and the cover member 8, the first and second drive rings 4 and 7 and a plurality of aperture blade groups (first aperture blade group 50 and second aperture blade group 60). Is driven.

  The engagement pin 5 b of the aperture blade 5 engages with the engagement hole 2 b of the base member 2. The cam pin 5 e of the aperture blade 5 engages with the cam groove 4 e of the first drive ring 4. The rotation of the pinion gear 3 is transmitted to the driven portion 4d of the first drive ring 4, and the first drive ring 4 rotates. When the first drive ring 4 rotates, a driving force is applied to the cam pin 5 e of the aperture blade 5 from the cam groove 4 e of the first drive ring 4, and the aperture blade 5 enters the opening 2 a of the base member 2. And evacuate (enter and exit). The aperture opening forming edge portion 5r of the first aperture blade group 50 forms a part of the aperture opening shape from the fully opened aperture to the minimum aperture.

  The engagement pin 6 c of the aperture blade 6 engages with the engagement hole 2 c of the base member 2. The cam pin 6 f of the aperture blade 6 engages with the cam groove 7 f of the second drive ring 7. The rotation of the pinion gear 3 is transmitted to the driven portion 7d of the second drive ring 7, and the second drive ring 7 rotates. When the second drive ring 7 rotates, a driving force is applied to the cam pin 6f of the diaphragm blade 6 from the cam groove 7f of the second drive ring 7, and the diaphragm blade 6 enters the opening 2a of the base member 2. And evacuate (enter and exit). The aperture opening forming edge 6r of the second aperture blade group 60 forms a part of the aperture opening shape from the fully opened aperture to the minimum aperture.

  The engaging holes 2b and 2c of the base member 2 are arranged on the outer peripheral side of the base member 2 so that the engaging pin 5b of the diaphragm blade 5 and the engaging pin 6c of the diaphragm blade 6 do not interfere with other diaphragm blades. . Further, the cam pin 5e of the diaphragm blade 5 and the cam pin 6f of the diaphragm blade 6 are arranged on opposite surfaces.

  When the engaging holes 2b and 2c of the base member 2 are arranged on the inner peripheral side, the engaging pin 5b of the diaphragm blade 5 or the engaging pin 6c of the diaphragm blade 6 interferes with other diaphragm blades. Further, if the cam pins 5e of the aperture blade 5 and the cam pins 6f of the aperture blade 6 are arranged on the same surface side, the cam pins will interfere with other blades. That is, the center of rotation of the diaphragm blades is arranged on the outer peripheral side in the radial direction of the diaphragm device 100, the cam pin of each diaphragm blade is arranged inside the rotational center of the blades in the radial direction of the diaphragm device 100, and The cam pins of the group are arranged on the side opposite to the cam pins of another aperture blade group.

  In the present embodiment, the engagement holes 2b and 2c of the base member 2 are engaged with the engagement pin 5b of the aperture blade 5 and the engagement pin 6c of the aperture blade 6, respectively. The engagement portion of the aperture blade may be formed as a hole by using a pin.

  FIG. 5 is a view showing the aperture shape of the aperture device of the present embodiment with the cover member 8 removed. FIG. 6 is an enlarged view of the shape of the aperture opening. The aperture shape is represented by (A), (B), (C), (D), and (E) in order of increasing aperture diameter. In the process of shifting from the full aperture to the minimum aperture, the aperture opening is formed by the aperture blade group 50 and the aperture blade group 60 cooperating with each other. In FIGS. 6A, 6B, and 6C, which are intermediate ranges (intermediate diaphragms) from the diaphragm fully opened, the diaphragm openings are formed by the diaphragm opening forming edges 5r of the plurality of diaphragm blades 5 and the diaphragms of the plurality of diaphragm blades 6. It is formed by the opening forming edge 6r. In FIGS. 6D and 6E, which are the minimum aperture from the middle area (intermediate aperture) of the aperture, the aperture is formed by the aperture opening forming edge 5r of the plurality of aperture blades 5.

  In the present embodiment, the group of diaphragm blades 50 is composed of nine diaphragm blades 5, and the group of diaphragm blades 60 is composed of nine diaphragm blades 6, so that the aperture opening shapes (A) in FIGS. , (B), and (C), a total of 18 diaphragm blades form a diaphragm aperture. The greater the number of blades forming the aperture opening, the closer the aperture can be to a circle. Therefore, the aperture shapes (A), (B), and (C) can form aperture apertures that are extremely close to circles. The aperture shapes (D) and (E) in FIGS. 5 and 6 are set so as to be formed by an aperture blade group 50 composed of nine aperture blades 5. The aperture opening forming edge 5r of the aperture blade 5 is set so as to have a shape close to a circle in the aperture opening shapes (D) and (E). For this reason, it is possible to form a very narrow aperture in the aperture shapes (D) and (E).

  Here, a problem when the number of diaphragm blades is increased when the number of diaphragm blades is one group will be described. If the number of aperture blades is large, the load due to the overlap of the aperture blades increases, and a phenomenon occurs in which a small aperture cannot be formed. For example, when the group of diaphragm blades is constituted by 18 diaphragm blades, the aperture opening may not be able to be reduced to a small diaphragm due to the overlapping load of the diaphragm blades. In the aperture opening states (D) and (E), when the group of the aperture blades is 18, the load becomes excessively large, and it is extremely difficult to form the state. In the present embodiment, since the number of aperture blade groups per group is nine, the aperture opening shape can be formed by the 18 aperture blades without increasing the load of overlapping of the blades.

  FIG. 7 is a diagram showing only the first diaphragm blade group 50. FIG. 8 is a diagram showing only the second diaphragm blade group 60. In the base member 2, engagement holes 2b and engagement holes 2c are alternately arranged on the circumference. In the diaphragm blade 5 constituting the first diaphragm blade group 50, the engaging pin 5b engages with the engaging hole 2b. In the diaphragm blade 6 constituting the second diaphragm blade group 60, the engaging pin 6c is engaged with the engaging hole 2c. That is, the first diaphragm blade group 50 and the second diaphragm blade group 60 are arranged on the base member 2 so as to have different phases in the circumferential direction. For example, the engagement pin 2b of one aperture blade 5 is arranged in the middle of the engagement pin 2c of the two aperture blades 6. By shifting the phase of each aperture blade group by half, the aperture opening shape can be made closer to a circle. As shown in FIG. 6B, the corners where the opening forming edges 6 r of the two diaphragm blades 6 when formed only by the second diaphragm blade group 60 intersect with the first diaphragm blade group 50. This is because it can be covered.

  Here, a feature of the present embodiment when the aperture is further reduced to a small aperture will be described. 7A, 7B, and 8C, since the first diaphragm blade group 50 and the second diaphragm blade group 60 form a diaphragm aperture in cooperation with each other, The size of the aperture opening of only the blade group is changed by the first diaphragm blade group 50 and the second diaphragm blade group 60 to have substantially the same size.

  As shown in FIG. 7, the first diaphragm blade group 50 (one diaphragm blade group) gradually reduces the diaphragm diameter from (A) to (B), (C), (D), and (E). It forms so that it may become. This can be adjusted by the shape of the cam groove 4e of the first drive ring 4. On the other hand, as shown in FIG. 8, the second aperture blade group 60 (the other aperture blade group) is changed so that the opening becomes smaller when shifting from (A) to (B) and (C). When shifting from (C) to (D) and (E), the opening is formed to be enlarged. This can be adjusted by the shape of the cam groove 7f of the second drive ring 7.

  Here, the reason why the second diaphragm blade group 60 is changed so that the opening is enlarged in the middle of the process in which the first diaphragm blade group 50 is changed from the fully opened diaphragm to the minimum diaphragm will be described. That is, when the first diaphragm blade group 50 forms a small diaphragm opening, the tip 5g of the diaphragm blade 5 collides with the opening forming edge 6r of the diaphragm blade 6 of the adjacent second diaphragm blade group 60. This is to prevent the diaphragm blades 6 from being pinched between the overlapping diaphragm blades 6. In the conventional light amount adjusting device, the aperture adjustment range as the light amount adjusting device is limited due to these problems. On the other hand, in the present embodiment, by changing the operation of one of the aperture blade groups in the direction of enlarging the aperture from the middle, the aperture adjustment range as the light amount adjusting device can be expanded.

  Further, the above reason will be described in detail. In the present embodiment, the diaphragm blade 5 is incorporated in a ring shape so that the tip 5g of the diaphragm blade 5 is braided toward the cover member 8 side. As the aperture diameter of the aperture blade 5 is reduced, the tip 5g is braided toward the cover member 8 and the second aperture blade group 60. The aperture blade 6 has the aperture blade 6 incorporated in a ring shape so that the tip 6g is braided toward the cover member 8 side. As the aperture diameter of the aperture blade 6 is reduced, the tip 6g is knitted toward the cover member 8 side. The first diaphragm blade group 50 and the second diaphragm blade group 60 are both configured to be knitted in one direction.

  FIG. 9 is a diagram showing the relationship between one diaphragm blade 5 (1) forming the first diaphragm blade group 50 and the second diaphragm blade group 60. FIG. 10 is a diagram extracted from the state of FIG. 9C. In the process of changing the aperture opening state from (A) of FIG. 9 to (B) and (C), the aperture blade 5 (1) forms one aperture blade 6 (1) forming the second aperture blade group 60. ). When the diaphragm blades 5 (1) and the second diaphragm blade group 60 are moved in the closing direction as they are, the tip 5g (1) of the diaphragm blades 5 (1) becomes the diaphragm forming the second diaphragm blade group 60. It collides with the opening forming edge 6r (2) of the blade 6 (2). Alternatively, the tip 5g (1) of the diaphragm blade 5 (1) is caught between the diaphragm blades 6 (1) and 6 (2) forming the second diaphragm blade group 60, causing malfunction. I will. Therefore, conventionally, the diameter of the aperture can be adjusted only within a range where the first aperture blade group 50 does not collide with the adjacent second aperture blade group 60. In order to increase the aperture adjustment range as the light amount adjusting device, it is necessary to increase the number of aperture blade groups to three layers as in JP-A-2017-58679.

  On the other hand, in the present embodiment, in the process of changing the aperture from the states (C) to (D) and (E), the aperture formed by the second aperture blade group 60 is changed in a direction to enlarge. By expanding the opening formed by the second diaphragm blade group 60, when forming the small diaphragm states (D) and (E) by the first diaphragm blade group 50, the tip 5g of the diaphragm blade 5 is stopped by the diaphragm. It is possible to prevent the blade 6 from colliding with the opening forming edge 6r or being caught between the aperture blades 6. By expanding the opening formed by the second diaphragm blade group 60, it is possible to widen the diaphragm range that can be formed by the first diaphragm blade group 50 in the small diaphragm direction.

  For example, the second diaphragm blade group 60 enters a position where the diaphragm aperture becomes as small as possible while contributing to the formation of the small diaphragm aperture, and then the first diaphragm blade group 50 forms a smaller diaphragm opening in the process of forming the smaller diaphragm aperture. By changing the aperture opening formed by the second aperture blade group 60 in the direction of enlargement, the second aperture blade group 60 is reduced to the smallest possible aperture, and the first aperture blade group is contributed to the formation of the aperture. The aperture range that can be formed by 50 can be expanded in the small aperture direction. Further, the knitting of the first diaphragm blade group 50 on the small diaphragm side can be suppressed by the second diaphragm blade group 60, so that the diaphragm range that can be formed by the first diaphragm blade group 50 is reduced in the smaller diaphragm direction. Can be spread out.

  In the above description, the aperture opening states (A), (B) and (C) of FIG. 5 are formed by a total of 18 blades of the first aperture blade group 50 and the second aperture blade group 60, The states (D) and (E) were formed by nine blades of the first diaphragm blade group 50. However, the aperture opening states (A) and (B) are formed by the nine blades of the second aperture blade group 60, and the aperture opening state (C) is set by the first aperture blade group 50 and the second aperture blade group. Alternatively, the aperture opening states (D) and (E) may be formed by nine blades of the first aperture blade group 50. Either one may be used as long as the shape of the aperture forming edges 5r and 6r of each aperture blade is appropriately set. The aperture opening state (C) may be formed by only one of the first aperture blade group 50 or the second aperture blade group 60, and may be formed in other aperture opening states (A) and (B). The aperture may be formed by a desired group of aperture blades.

  Next, the reason why the present embodiment can increase the number of aperture blades and form a good aperture shape while maintaining high aperture accuracy will be described. In the present embodiment, cam grooves are formed in two parts, the first drive ring 4 and the second drive ring 7. The entrance and exit of the aperture blades 5 and 6 into and from the opening 2a can be adjusted by the shape of the cam groove. The longer the cam groove, the higher the resolution. When the number of members forming the cam groove is two, the cam groove can be formed longer than when the number of members forming the cam groove is one. That is, by forming long cam grooves in the two components of the first drive ring 4 and the second drive ring 7, it is possible to maintain high aperture accuracy.

  FIG. 11 is a projection view in which the first drive ring 4 and the second drive ring 7 are overlapped. It can be seen that the nine cam grooves 4e of the first drive ring 4 and the nine cam grooves 7f of the second drive ring 7 overlap in a projected state. Here, when the first diaphragm blade group 50 and the second diaphragm blade group 60 are driven by one drive ring, it is necessary to form a total of 18 cam grooves in one drive ring. Since the grooves cannot be overlapped and a gap (thickness) between the cam grooves is required to allow the components to be formed, it is necessary to make the cam grooves extremely short. That is, with one drive ring, it is necessary to shorten the cam groove in order to increase the cam groove, and it is extremely difficult to maintain the aperture accuracy. Furthermore, as the number of cam grooves arranged on one drive ring increases, not only the cam grooves become shorter, but also the angle of the cam grooves becomes steeper, so that the power consumption for rotating the drive ring increases. In the present embodiment, since a long cam groove can be formed in the two parts of the first drive ring 4 and the second drive ring 7, it is possible to maintain high aperture precision and to reduce consumption. It can be driven by electric power. Further, it is possible to reduce the thickness of the drive ring while securing the strength for driving the blade group. In the present embodiment, the cam grooves of the first drive ring 4 and the second drive ring 7 are configured so as to partially overlap in the optical axis direction as shown in FIG. The present invention is not limited to this, and may be configured such that the cam grooves do not overlap in the optical axis direction. Even in such a case, it is possible to provide a longer cam groove as compared with a case where a total of 18 cam grooves are provided in one drive ring, and it is also easy to increase the interval between the cam grooves. In addition, the rigidity of each drive ring can be improved.

  The first drive ring 4 and the second drive ring 7 can be driven simultaneously by the same drive unit 1. Further, in the present embodiment, the driving unit 1 is used as a driving source, but the first driving ring 4 and the second driving ring 7 may be manually rotated. Further, in the present embodiment, the driving force of the driving unit 1 is transmitted to the first driving ring 4 and the second driving ring 7 by the pinion gear 3, but the driving unit 1 is provided with an arm member having a driving pin. Alternatively, the driving pins may be engaged with the engaging grooves of the first driving ring 4 and the second driving ring 7 to transmit the driving force.

  In the present embodiment, since the first diaphragm blade group 50 and the second diaphragm blade group 60 are operated adjacent to each other, the position of the diaphragm opening changes in the optical axis direction in the process of shifting from opening to the minimum diaphragm. Less to do. This is because the distance between the aperture blade groups can be maintained by incorporating the aperture blade groups so as to be knitted in the same direction. In general, the smaller the aperture is, the larger the weaving of the aperture blades is. However, in this embodiment, as shown in FIG. Thus, the change in the position of the aperture opening in the optical axis direction can be reduced. Therefore, when incorporating the light amount adjusting device of the present embodiment into the lens barrel, the distance from the lens can be reduced.

  Although the position of the aperture opening slightly changes in the optical axis direction, the first aperture blade group 50 and the second aperture blade group 60 have their braiding directions opposite to each other so that they are knitted back to back. May be arranged so as to face the opposite side of the group of aperture blades.

  FIG. 12A is an exploded perspective view of a diaphragm device 150 according to a modification of the present embodiment. FIG. 12B is an exploded perspective view of the diaphragm device 150 as viewed from the upside down direction of FIG. 12A. FIG. 13 is a side sectional view of the diaphragm device 150.

  In this modification, the opening 20a at the center of the base member 20 and the opening 80a at the center of the cover member 80 are formed to be large, and the light passage opening is formed by the opening 40a of the first drive ring 40 or the second opening. It is defined by the opening 70 a of the drive ring 70. In the first drive ring 40, engagement claws 40 b are formed at three places on the circumference. As shown in FIG. 13, the engagement claws 40 b are formed on the three groove portions 20 b of the base member 20. Is engaged. Further, the second drive ring 70 has extended portions 70 c formed at three circumferential positions, and is supported by three projections 20 c formed on the base member 20. With such a structure, the first and second drive rings 40 and 70 are supported by the base member 20, the position in the optical axis direction is regulated, and the operation of the aperture device 150 is stabilized.

  Since the aperture device of the present embodiment can reduce the distance from the lens, the degree of freedom in optical design can be improved, which contributes to improvement in optical characteristics and downsizing of the optical device.

  Further, in the present embodiment, there is no need to insert a partition member or the like between the aperture blade groups. Conventionally, when an aperture opening is formed by a plurality of aperture blade groups, a partition member may be inserted between the aperture blade groups, or partitioned by a rotating member, in order to avoid collision between the blades. In the present embodiment, the reason why stable operation can be realized without inserting a partition member between the respective aperture blade groups is that one of the aperture blade groups described above is moved in the opening direction during the process of narrowing the aperture blade from the open state to the small aperture. This is because it is possible to prevent collision with other diaphragm blade groups. In addition, since the diaphragm blades having no cam grooves or holes are formed, the fear that the diaphragm blades collide with the cam grooves and holes or are caught can be eliminated. Since there is no need to insert a partition member between the aperture blade groups, the difference between the aperture openings in the optical axis direction is small. Further, it is effective for reducing the thickness of the aperture device.

<Second embodiment>
FIG. 14 is an exploded perspective view of a diaphragm device which is a second embodiment of the light amount adjusting device of the present invention.

  In FIG. 14, a base member 202 (opening forming member) serving as a base of the diaphragm device 200 has an opening 202a at the center corresponding to the optical axis O of the lens, through which light passes. A cam pin 202c is formed outside the opening 202a.

  The base member 202 is generally formed by molding resin. A drive unit 201 using, for example, a stepping motor, a galvanometer, or the like is attached to the base member 202, and a pinion gear 203 is attached to a rotation shaft of the drive unit 201.

  The drive ring 204 for driving the first and second aperture blade groups 250 and 260, which will be described later, has an engagement pin 204e and a driven portion 204d. The drive ring 204 is generally formed by molding a resin, but may be formed by, for example, pressing a resin film (such as a PET sheet material).

  The inner engagement portion 204k of the drive ring 204 is rotatably engaged with the outer engagement portion 202k of the base member 202. The outer engaging portion 2k of the base member 202 may have a continuous circular shape, but may be configured by a plurality of convex portions and configured to engage with the inner engaging portion 204k of the drive ring 204. Good.

  In this embodiment, the drive ring 204 is engaged with the outside of the outer engagement portion 202k of the base member 220. However, an outer engagement portion is formed on the drive ring 204, and the inner engagement portion is formed on the base member 202. And the drive ring 204 may be engaged with the inside of the inside engagement portion of the base member 202.

  The drive ring 204 has a gear portion that is a driven portion 204d. The driven portion 204d meshes with the pinion gear 203, and the rotational force generated by the driving portion 201 is transmitted from the pinion gear 203 to the driven portion 204d, so that the drive ring 204 is rotated.

  Above the drive ring 204, a first diaphragm blade group 250 is arranged. The first diaphragm blade group 250 includes a plurality of diaphragm blades 205. In the present embodiment, a first diaphragm blade group 250 is composed of seven diaphragm blades 205. However, the number of diaphragm blades may be any number as long as the diaphragm blades are composed of a plurality of diaphragm blades. The aperture blade 205 has an aperture opening forming edge 205r, an engagement hole 205e, and a cam groove 205c.

  Above the first diaphragm blade group 250, a second diaphragm blade group 260 is arranged. The second diaphragm blade group 260 includes a plurality of diaphragm blades 206. In the present embodiment, the second diaphragm blade group 260 is constituted by the seven diaphragm blades 206. However, the number of diaphragm blades may be any number as long as the diaphragm blades are composed of a plurality of diaphragm blades. The aperture blade 206 has an aperture opening forming edge 206r, an engagement hole 206e, and a cam groove 206c.

  The aperture blade 205 and the aperture blade 206 are formed by, for example, pressing a PET sheet material or the like. Further, it is desirable that the aperture blades be subjected to a light-shielding process, an anti-reflection process, a sliding process, and the like.

  Above the second diaphragm blade group 206, a cover member 208 having an opening 208a formed in the center is disposed. In the space formed by the base member 202 and the cover member 208, the drive ring 204 and a plurality of aperture blade groups (a first aperture blade group 250 and a second aperture blade group 260) are driven.

  An engagement hole 205e of the aperture blade 205 and an engagement hole 206e of the aperture blade 206 rotatably engage with an engagement pin 204e of the drive ring 204. The cam groove 205c of the diaphragm blade 205 and the cam groove 206c of the diaphragm blade 206 engage with the cam pin 202c of the base member 202. The rotation of the pinion gear 203 is transmitted to the driven portion 204d of the drive ring 204, and the drive ring 204 rotates. When the drive ring 204 rotates, the driving force is transmitted from the engagement pin 204e of the drive ring 204 to the engagement hole 205e of the aperture blade 205 and the engagement hole 206e of the aperture blade 206, and the first aperture blade group 250 and the second The aperture blade group 260 rotates around the opening 202a of the base member 202.

  Since the cam groove 205c of the diaphragm blade 205 and the cam groove 206c of the diaphragm blade 206 are engaged with the cam pin 202c of the base member 202, the shape of the cam groove 205c and the cam groove 206c causes the diaphragm blade 205 and the diaphragm blade 206 to move. It goes in and out of the opening 202a. In the range from the maximum aperture to the minimum aperture, the aperture is limited only by the aperture opening forming edge 205r of the first aperture blade group 250, or only by the aperture opening forming edge 206r of the second aperture blade group 260, or The aperture opening forming edge 205r of the first aperture blade group 250 and the aperture opening forming edge 206r of the second aperture blade group 260 are formed in cooperation.

  In the second embodiment, the engagement pin 204e is arranged on the drive ring 204 and the cam pin 202c is arranged on the base member 202. However, the cam pin is arranged on the drive ring 204 and engaged with the cam groove of each aperture blade. Alternatively, an engagement pin may be arranged on the base member and engaged with an engagement hole of each aperture blade. In this case, unlike the arrangement of FIG. 14, the position of the cam pins of the drive ring 204 may be radially inward, and the position of the engagement pins of the base member may be radially outward.

  FIG. 15 is a diagram showing the aperture shape of the aperture device of the present embodiment with the cover member 208 removed. FIG. 16 is an enlarged view of the shape of the aperture opening. The aperture shape is represented by (A), (B), (C), (D), and (E) in order of increasing aperture diameter. In the process of shifting from the full aperture to the minimum aperture, the aperture aperture is formed by the aperture blade group 250 and the aperture blade group 260 cooperating with each other.

  In FIG. 16A on the open side of the aperture, the aperture is formed by the aperture opening forming edge portion 206 r of the plurality of aperture blades 206. In FIGS. 16B and 16C, which are the intermediate aperture regions, the aperture openings are formed by the aperture opening forming edges 205r of the plurality of aperture blades 205 and the aperture opening forming edges 206r of the plurality of aperture blades 206. . In FIGS. 16D and 16E, which are the small stop areas of the stop, the stop openings are formed by the stop opening forming edges 205r of the plurality of stop blades 205.

  In the process of shifting from the full aperture to the minimum aperture, a movement that changes from FIG. 16D to FIG. 16E will be described. When changing from FIG. 16 (D) to FIG. 16 (E), the aperture opening is formed by moving the first aperture blade group 205 in the closing direction. At this time, the second diaphragm blade group 260 is moved in a direction in which the opening opens. This is because, similarly to the first embodiment, the tip of the aperture blade 205 of the first aperture blade group 250 collides with the opening forming edge 206r of the aperture blade 206 or is sandwiched between the aperture blades 206. This is to prevent By moving the second diaphragm blade group 260 in the direction in which the opening opens, the first diaphragm blade group 250 can form a smaller diaphragm diameter.

  As described above, when the second diaphragm blade group 260 is moved in the opening direction on the small diaphragm side, as shown in FIG. 14, the cam groove 206c formed in the diaphragm blade 206 is formed. A portion 206f that bends at a steep angle is formed. When the steep angle portion 206f is disposed adjacent to the drive ring 204, it is conceivable that the steep angle portion 206f is turned up by the movement of the drive ring 204. For this reason, in the present embodiment, the first diaphragm blade group 250 is interposed between the second diaphragm blade group 260 and the drive ring 204 to suppress the curling up.

  In the second embodiment, since the first diaphragm blade 250 and the second diaphragm blade group 260 are operated adjacent to each other, the position of the diaphragm opening in the direction of the optical axis in the process of shifting from the opening to the minimum diaphragm. Little change. This is because the distance between the aperture blade groups can be maintained by incorporating the aperture blade groups so as to be knitted in the same direction. In general, the braid of the aperture blades increases as the aperture is reduced, but in the second embodiment, as shown in FIG. 16E, the braid of the first aperture blade group 250 is reduced. Since it can be held down by the second diaphragm blade group 260, it is possible to reduce a change in the position of the diaphragm aperture in the optical axis direction. Therefore, when the diaphragm device according to the second embodiment is incorporated in the lens barrel, the distance from the lens can be reduced.

  Although the position of the aperture opening slightly changes in the optical axis direction, the first aperture blade group 250 and the second aperture blade group 260 have their braiding directions opposite to each other so that they are knitted back to back. May be arranged so as to face the opposite side of the group of aperture blades.

  Since the aperture device of the present embodiment can reduce the distance from the lens, the degree of freedom in optical design can be improved, which contributes to improvement of optical characteristics and downsizing and thinning of the optical device.

  Further, in the present embodiment, there is no need to insert a partition member or the like between the aperture blade groups. Conventionally, when an aperture opening is formed by a plurality of aperture blade groups, a partition member may be inserted between the aperture blade groups, or partitioned by a rotating member, in order to avoid collision between the blades. In the present embodiment, the reason why stable operation can be realized without inserting a partition member between the respective aperture blade groups is that one of the aperture blade groups described above is moved in the opening direction during the process of narrowing the aperture blade from the open state to the small aperture. This is because it is possible to prevent collision with other diaphragm blade groups. Since there is no need to insert a partition member between the aperture blade groups, the difference between the aperture openings in the optical axis direction is small. Further, it is effective for reducing the thickness of the aperture device.

<Third embodiment>
FIG. 17 shows an interchangeable lens 221 for a single-lens reflex camera as an optical device equipped with the above-described aperture device, and an internal configuration of a camera body to which the interchangeable lens is attached.

  A photographing optical system including a variable power lens 232, a diaphragm device 100 according to any one of the first to third embodiments arranged between the lenses, and a focusing lens 229, disposed within the lens barrel of the interchangeable lens 221. Is housed.

  An image sensor 225 composed of a photoelectric conversion element such as a CCD sensor or a CMOS sensor is disposed in the camera body, and photoelectrically converts a subject image formed by the interchangeable lens 221 to output an electric signal. The brightness of the subject image formed on the image sensor 225 (that is, the amount of light reaching the image sensor 25) is appropriately set by changing the aperture of the aperture device 100 or moving the ND filter forward or backward. Can be.

  The electric signal output from the image sensor 225 is converted into a digital signal in the image processing circuit 226 and subjected to various image processing. Thereby, an image signal is generated.

  By rotating the zoom ring 231, the user can move the zoom lens 232 to perform zooming (zooming). The controller 222 detects the contrast of the image signal, controls the focus motor 228 according to the contrast, and moves the focus lens 229 to perform autofocus. Alternatively, the controller 222 may control the focus motor 228 and move the focus lens 229 to perform autofocus based on a detection signal of a focus detection unit using a phase difference detection method (not shown).

  Further, the controller 222 controls the drive unit 1 of the diaphragm device 100 based on a photometric value of a photometric unit (not shown) or an image signal to adjust the light amount. Thereby, blur and ghost at the time of shooting can be made into a natural shape, and a high-quality image can be recorded.

  The present invention is not limited to the above-described single-lens reflex camera, but can be widely applied to optical devices such as a digital camera and a video camera with an integrated lens. According to the aspect of the present invention, it is possible to realize an optical device having an excellent light amount adjusting function by forming light passage openings having different diameters and high circularity.

1: drive unit, 2: base member, 3: pinion gear, 4: first drive ring, 5: first aperture blade group, 6: second aperture blade group, 7: second drive ring, 8 ： Cover member

Claims (7)

A base member having a light passage opening;
A first diaphragm blade group including a plurality of first diaphragm blades that enter and exit the light passage opening;
A second group of diaphragm blades including a plurality of second diaphragm blades that enter and exit the light passage opening;
With
In the process of changing from a fully opened aperture to an intermediate aperture, only the first aperture blade group, only the second aperture blade group, or the aperture opening is cooperated by the first and second aperture blade groups. In the process of forming and changing from the intermediate aperture to the minimum aperture, only one of the first and second aperture blades forms an aperture, and the other aperture is in the direction in which the aperture opens. A light amount adjusting device characterized in that the light amount adjusting device moves.   The first group of aperture blades is annularly overlapped around the light passage opening and is incorporated so as to be knitted in one direction along the optical axis, and the second group of aperture blades is formed of the light passage opening. The light amount adjusting device according to claim 1, wherein the light amount adjusting device is integrated so as to be annularly overlapped with the periphery and knit along the optical axis in the same direction as the one direction.   3. The one-way aperture blade group arranged on the one direction side with respect to the one aperture blade group forming the aperture aperture in a process of changing from an intermediate aperture to a minimum aperture. Light intensity control device.   The first aperture blade group and the second aperture blade group receive driving force from a drive ring that rotates around the light passage opening, and enter and exit the light passage opening. The light amount adjustment device according to any one of claims 1 to 3.   The first aperture blade has a first rotation center engagement portion and a first cam groove, and the second aperture blade has a second rotation center engagement portion, a second cam groove, 5. The base member has a cam pin, and the cam pin is engaged with the first cam groove and the second cam groove. A light amount adjusting device according to the item. The first aperture blade has a first rotation center engagement portion and a first cam groove, and the second aperture blade has a second rotation center engagement portion, a second cam groove, Has,
A drive ring that rotates around the light passage opening and applies a driving force to the first aperture blade and the second aperture blade;
4. The light amount adjusting device according to claim 1, wherein a cam pin of the driving ring is engaged with the first cam groove and the second cam groove. 5. A lens barrel forming the optical path, and a plurality of lenses disposed in the lens barrel,
7. An optical apparatus, wherein the light amount adjusting device according to claim 1 is arranged between the plurality of lenses.