JP2019179167A - Light quantity adjusting device - Google Patents

Abstract

To provide a light quantity adjusting device for driving a plurality of aperture blades and changing an aperture diameter, with which a series of aperture operations from full open to a minimum aperture can be smoothly performed.SOLUTION: The light quantity adjusting device comprises a base member having an opening, a plurality of aperture blades for adjusting the size of the opening by rotating one on top of another, and a cover member including an opening and supporting the plurality of aperture blades between the base member and itself. The aperture blades include a protrusion the thickness of which corresponds to a space between the base member and the cover member at a position where the aperture blades do not overlap each other during opening/closing operation of the aperture blades.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a light amount adjusting device such as a diaphragm device mounted on an optical apparatus such as a camera or an interchangeable lens.

  In general, a diaphragm device including a diaphragm blade and a blade driving device for driving the diaphragm blade has a base member having an opening corresponding to the photographing optical path, and is supported by the base member to open and close the opening. A plurality of diaphragm blades that operate as described above, and a drive ring that rotates. A plurality of blades are driven by this drive ring to open and close, thereby performing a series of aperture operations from opening to minimum aperture.

  In general, in the diaphragm device having such a structure, the plurality of diaphragm blades forming the opening are driven to open and close in a sliding space in the optical axis direction formed between the base member and the guide member. At this time, the plurality of aperture blades are overlapped most when the opening is opened, and the overlap gradually decreases as the aperture is reduced. Since the sliding space of the diaphragm blades is usually set broadly in accordance with the open side where the number of overlapped diaphragm blades increases, the sliding of the blades decreases as the blade overlaps gradually from the open side. A gap is created between the space and the aperture blade.

  Patent Document 1 discloses a structure of a diaphragm device for solving such a problem. A light amount adjusting device as a diaphragm device disclosed in Patent Document 1 includes a ring-shaped base member having an optical path opening, a guide member provided opposite to the base member, and between the base member and the guide member. A plurality of aperture blades that slide in a circumferential direction while overlapping each other in a slide space provided in the aperture, and that open and close the optical path opening, and the base member and the guide are interlocked with the slide of the aperture blades It is comprised so that the space | interval of the sliding space between members may be changed.

  In this light amount adjusting device, the sliding space between the base member and the guide member can be changed according to the overlap of the diaphragm blades in conjunction with the sliding of the plurality of diaphragm blades when the optical path opening is narrowed. . As a result, the load torque accompanying the opening / closing operation of the plurality of aperture blades can be made constant between the open side of the optical path opening and the minimum aperture side, and a series of aperture operations from the fully open to the minimum aperture can be performed smoothly. It is supposed to be possible.

JP 2017-120347 A

  However, in the structure of Patent Document 1, a cam surface is formed on the base member in order to change the sliding space of the aperture blade as it changes from the open side to the small aperture side, and the blade slides on this cam surface. This is a structure that makes the load torque generated by this constant. For this reason, the sliding space on the small aperture side is set wide, and there is a problem that fluctuations in the optical axis direction of the aperture blades on the small aperture side are likely to occur.

  The light quantity adjusting device according to the present invention includes a base member having an opening, a plurality of diaphragm blades that adjust the size of the opening by rotating in an overlapping manner, and an opening, and the base member A cover member that supports the plurality of diaphragm blades, and the diaphragm blades correspond to a gap between the base member and the cover member at a position where the diaphragm blades do not overlap each other when the diaphragm blades are opened and closed. It has a protrusion part of thickness.

  According to the present invention, in a light amount adjusting device that changes a diaphragm diameter by driving a plurality of diaphragm blades, it is possible to stably perform a series of diaphragm operations from fully open to the minimum diaphragm.

The disassembled perspective view which shows the structure which looked at the light quantity adjustment apparatus concerning one Embodiment of this invention from the upper side. The disassembled perspective view which looked at the light quantity adjustment apparatus 10 from the lower side. The enlarged view of the aperture blade used for the light quantity adjustment apparatus of one Embodiment. The side view of the aperture blade used for the light quantity adjustment apparatus of one Embodiment. The figure which looked at the aperture blade in the open state of the light quantity adjustment apparatus of one Embodiment from the optical axis direction. The figure which looked at the stop blade in the middle stop state of the light quantity adjusting device of one embodiment from the optical axis direction. The figure which looked at the aperture blade in the small aperture state of the light quantity adjustment apparatus of one Embodiment from the optical axis direction. The assembly external view of the light quantity adjustment apparatus of one Embodiment. XX sectional drawing of the light quantity adjustment apparatus of one Embodiment. The figure which further shows the shape of the protrusion part formed in an aperture blade. The figure which shows the maximum shape of the protrusion part formed in an aperture blade. The figure which shows the overlap of an aperture blade when an aperture blade operate | moves from an open state to a small aperture state. The disassembled perspective view of the light quantity adjustment apparatus when the magnitude | size of a protrusion part is made into the maximum dimension. The figure which showed the example by which the opening-and-closing guide cam is formed in the aperture blade. YY sectional drawing of FIG. It is a figure which shows the example which formed the opening-and-closing guide cam in the aperture blade, and formed the cam pin in the base member. The figure which shows the maximum shape of a protrusion part at the time of forming an opening-and-closing guide cam in an aperture blade. ZZ sectional drawing of FIG. The disassembled perspective view of the light quantity adjusting device when the opening / closing guide cam is formed on the diaphragm blade and the size of the protruding portion is the maximum dimension.

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

  FIG. 1 is an exploded perspective view showing a configuration of a light amount adjusting device 10 according to an embodiment of the present invention as viewed from above. FIG. 2 is an exploded perspective view of the light amount adjusting device 10 as viewed from below. 3 is an enlarged view of the aperture blade 2, and FIG. 4 is an enlarged side view of the aperture blade 2. As shown in FIG. FIGS. 5 to 7 are plan views showing how the diaphragm blades are driven from the open state to the narrowed state. Further, FIG. 8 is an external view of the assembly of the light amount adjusting device, and FIG. 9 is a cross-sectional view taken along the line XX of FIG.

  The light quantity adjusting device 10 includes a base member 1 having an optical path opening 11 centered on the optical axis and open / close guide cams (cam grooves) 1a to 1i, a plurality (9 in this embodiment) of diaphragm blades 2a to 2i, A drive plate 3 that opens and closes the aperture blades 2a to 2i and a cover member 4 that slidably presses the drive plate 3 are provided.

  The base member 1 is a ring-shaped member that forms the opening 11, and the protrusions 12 a to serve as a plurality of support portions that support the drive plate 3 and form the sliding spaces A (see FIG. 9) of the diaphragm blades 2 a to 2 i. 12i and a plurality of opening / closing guide cams 1a to 1i corresponding to the number of diaphragm blades 2.

  The open / close guide cams 1a to 1i are engaged with cam pins 21a to 21i provided on the base portions 20a to 20i of the diaphragm blades as shown in FIG. By moving the cam pins 21a to 21i along the opening / closing guide cams 1a to 1i, the diaphragm blades can be opened or closed.

  The drive plate 3 is generally formed in a ring shape by resin molding or metal. A gear 3j is formed on a part of the outer peripheral portion of the drive plate 3, and meshes with the pinion gear 6 of the drive motor 5 attached to the cover member 4 and is driven to rotate. The drive motor 5 can rotate clockwise and counterclockwise, and the drive plate 3 rotates within a set rotation range by the rotation of the drive motor 5. The drive shafts 3a to 3i provided in the drive plate 3 are engaged with the drive pins 22a to 22i provided on the opposite side of the cam pins 21a to 21i of the plurality of stop blades, so that the stop blades 2a to 2i are engaged. 2i is opened and closed, the opening is changed, and the amount of light is adjusted.

  The diaphragm blades in the present embodiment are configured by nine diaphragm blades 2a to 2i, and each blade is provided with cam pins 21a to 21i and drive pins 22a to 22i, as shown in FIG. The blade portions 23a to 23i of the respective diaphragm blades are arranged at equal angular intervals around the optical axis, and an opening is formed on the inner peripheral side of the diaphragm blades 2a to 2i by overlapping a part of the blades. And the rotation of the drive ring 3 changes the size of the opening continuously by changing the overlap of the blades.

  As shown in FIG. 3, the diaphragm blades 2 a to 2 i are configured such that drive pins 22 a to 22 i and cam pins 21 a to 21 i are arranged in the blade portions 23 a to 23 i. In general, the diaphragm blades 2a to 2i are integrally formed with blade portions 23a to 23i, base portions 20a to 20i, drive pins 22a to 22i, and cam pins 21a to 21i by resin molding. In consideration of the ease of flow during molding of the resin, as shown in FIG. 4, the thickness of the base portions 20 a to 20 i is set to be thicker than the thickness of the blade portions 23 a to 23 i, and the molten resin is introduced from the base portions 20 a to 20 i side. Molding is performed so as to flow toward the blade portions 23a to 23i.

  In addition, the manufacturing method of the aperture blades 2a to 2i is not limited to resin molding. The blade portions 23a to 23i are formed by a light-shielded sheet member, and the drive pins 22a to 22i and the cam pins 21a to 21i are resin molded. And may be integrated with the blade portions 23a to 23i by adhesion, welding, outsert molding, or the like. Alternatively, the drive pins 22a to 22i and the cam pins 21a to 21i may be formed by metal pins and integrated with the blade portions 23a to 23i by adhesion, welding, caulking, or the like.

  The cover member 4 has a fitting hole 4j (see FIG. 2) to which the drive motor 5 is attached. Further, the cover member 4 may be provided with a mounting shape when the light amount adjusting device 10 is incorporated in the imaging device. The cover member 4 is formed in a ring shape by a resin mold like the drive plate 3, and the convex portions 4 a to 4 h provided in the circumferential direction on the inner diameter side and the outer peripheral portion 31 of the drive plate 3 slide. The drive plate 3 is supported rotatably.

  The above is the description of the schematic configuration of the light amount adjusting device. Next, a further characteristic configuration of the present embodiment will be described.

  In the light quantity adjusting device of the present embodiment, as shown in FIGS. 3, 4, and 5 to 7, the protrusions 24 a to 24 are formed at locations where the diaphragm blades do not overlap each other when the plurality of diaphragm blades 2 a to 2 i are opened and closed. 24i is provided. The thicknesses 211a to 211i of the protrusions 24a to 24i shown in FIG. 4 are set to, for example, the thickness of about two sheets of the thickness 213a of the blade part 23a. Due to the presence of the protrusions 24a to 24i, the sliding thickness of the diaphragm blades is the thickness obtained by adding the thickness of the base portion 20a of the diaphragm blade 2 to the thickness 211a to 211i, whether the diaphragm blades 2a to 2i are overlapped or not. It is determined at 212a to 212i. The thicknesses 212a to 212i are set so that the diaphragm blades 2a to 2i are substantially equal to the total thickness of the blades that overlap each other in the open state. Therefore, by determining the distance of the sliding space A between the drive plate 3 and the base member 1 in accordance with the thicknesses 212a to 212i, even when the aperture blades overlap most when the opening is opened, the small aperture Even in the state where the overlap of the diaphragm blades at the time is reduced, the space in the thickness direction occupied by the diaphragm blades in the sliding space A is constant at the thicknesses 212a to 212i. This prevents, for example, a gap from being generated between the sliding space A and the diaphragm blades in the case of a small diaphragm in which the overlapping of the diaphragm blades 2a to 2i is reduced, thereby improving the performance change due to the posture variation. it can.

  The protrusions 24a to 24i are formed in a partially thick shape when the diaphragm blades 2a to 2i are resin-molded, and are bonded, welded, or outsert to the diaphragm blades 2a to 2i when formed with a sheet member. It is formed by molding.

  The protrusions 24a to 24i are provided so that the diaphragm blades 2a to 2i do not overlap during the opening and closing operation, for example, around the cam pins 21a to 21i in a range that does not contact the adjacent diaphragm blades 23a to 23i during the opening and closing operation. And as already explained, the thicknesses 211a to 211i of the protrusions are preferably set to be equal to or more than two of the thicknesses 213a to 213i of the blades 23a whose overlap changes by the opening / closing operation.

  Next, FIG. 10 is a figure which further shows the shape of protrusion part 24a-24i. Since the shapes of the diaphragm blades 2a to 2i are all the same, the shape of the diaphragm blades 2a will be described below as an example.

  The aperture blade 2a is formed by resin molding, and at the time of molding, the resin flows from the cam pin 21a toward the blade portion 23a. At that time, the molten resin is preferably easier to flow in the longitudinal direction of the diaphragm blade indicated by the arrow B. Therefore, in this embodiment, in order to facilitate the resin to flow from the thick part of the protruding part 24a into the thin blade part 23a, the slope 24a-1 is provided on the side surface in the arrow B direction of the protruding part 24a. The slope 24a-2 is provided in the direction of the arrow C, which is the width direction (short direction) of the diaphragm blade 2a, in order to facilitate the flow of the resin. Makes the slope gentler than the slope 24a-2. In this way, by providing the inclined surface in which the protruding amount of the protruding portion 24a gradually decreases in the longitudinal direction of the aperture blade 2a, the protruding portion 24a and the aperture blade 2a are molded well.

  Next, FIG. 11 is a diagram illustrating the maximum shape of the protrusion 24a, and FIG. 12 is a diagram illustrating overlap of the diaphragm blades when the diaphragm blades are operated from the open state to the small diaphragm state.

  The protrusion 24a needs not to interfere with the diaphragm blades 2a to 2i at any position when the diaphragm blades 2a to 2i are opened and closed. Therefore, when the aperture blades 2a to 2i are in the open state, as shown in FIG. 11A, the maximum line 24a-3 that does not interfere with the adjacent aperture blade 2b is in the width direction of the protrusion 24a. Maximum position. When the aperture blades 2a to 2i are in the small aperture state, as shown in FIG. 11C, the line 24a-4 that does not protrude from the opening 11 of the base member 1 is the maximum position in the longitudinal direction. Become. Thus, the maximum dimension of the protrusion 24a is determined as a range that does not interfere with the movement of the aperture blades 2a to 2i and the position of the opening 11. What is necessary is just to determine the magnitude | size of the actual protrusion part 24a to arbitrary magnitude | sizes within the range of this maximum dimension.

  FIG. 13 is an exploded perspective view of the light amount adjusting device 10 when the size of the protruding portion 24a is the maximum dimension.

  Next, FIG. 14 is a view showing an example in which an opening / closing guide cam 25a is formed on the diaphragm blade 2a. 15 is a cross-sectional view taken along line YY of FIG. In the above embodiment, an example in which the opening / closing guide cams 1a to 1i are formed on the base member 1 and the cam pins 21a are formed on the diaphragm blades 2a to 2i has been described. However, as shown in FIGS. 14 and 15, the arrangement of the opening / closing guide cam and the cam pin may be reversed between the base member 1 and the aperture blades 2a to 2i.

  Also in this case, in order to stabilize the movement of the diaphragm blade 2a, and so as not to interfere with the movement of the adjacent diaphragm blade, it is preferable that the protruding portion 24a is disposed near the opening / closing guide cam 25a.

  FIG. 16 is a view showing an example in which the opening / closing guide cam 25a is formed on the aperture blade 2a, and the cam pin 13a is formed on the base member 1 to be engaged with the opening / closing guide cam 25a.

  Next, FIG. 17 is a view showing the maximum shape of the protruding portion 24a when the opening / closing guide cam 25a is formed on the aperture blade 2a, and FIG. 18 is a ZZ sectional view of FIG.

  In the case of the example of FIG. 17, the protrusions 24a are formed on both sides of the opening / closing guide cam 25a. The maximum shape of the protrusion 24a is determined as a range that does not interfere with the movement of the aperture blades 2a to 2i and the position of the opening 11 in the same manner as the example shown in FIG.

  FIG. 19 is an exploded perspective view of the light amount adjusting device 10 when the opening / closing guide cam 25a is formed on the aperture blade 2a and the size of the protruding portion 24a is the maximum dimension.

  As described above, in the light amount adjusting device 10 of the present embodiment, a gap is formed between the sliding space A and the aperture blades 2a to 2i due to a change in the overlap of the aperture blades 2a to 2i in the aperture operation of the optical path opening 11. Can be prevented. Therefore, the influence on the performance due to the posture difference variation in a state where the overlap of the diaphragm blades is small is suppressed. As described above, the variation in posture difference can be suppressed from the open state of the optical path opening 11 to the minimum aperture state, and the opening / closing operation can be stably performed, so that the light amount adjustment by the imaging device such as a camera can be accurately performed. In addition, the manufacturing cost can be kept low because of the simple configuration in which only a part of the shape of the aperture blade is protruded.

1: Base members 2a to 2i: Aperture blades 3: Drive plate 4: Cover member 5: Drive motor 6: Pinion gear

Claims (6)

A base member having an opening;
A plurality of diaphragm blades that adjust the size of the opening by rotating in an overlapping manner;
A cover member having an opening and supporting the plurality of diaphragm blades with the base member,
The aperture blade has a protrusion with a thickness corresponding to the gap between the base member and the cover member at a position where the aperture blades do not overlap when the aperture blade is opened and closed. .   The light quantity adjustment according to claim 1, wherein the aperture blade has a cam pin that engages with a cam groove formed in the base member, and the protrusion is formed around the cam pin. apparatus.   2. The light quantity according to claim 1, wherein the aperture blade has a cam groove that engages with a cam pin disposed on the base member, and the protrusion is formed around the cam groove. Adjusting device. The total thickness of the protrusions and the diaphragm blades on which the protrusions are formed is substantially equal to the total thickness of the diaphragm blades in the open state. The light quantity adjusting device according to any one of claims 1 to 3.   5. The light amount adjusting device according to claim 1, wherein the protruding portion has an inclined surface in which a protruding amount gradually decreases with respect to a longitudinal direction of the aperture blade.   The light amount adjusting device according to claim 1, wherein the protruding portion has a slope that is gentle in the longitudinal direction of the diaphragm blades and steep in the short direction.