JP2019179169A - Light quantity adjusting device - Google Patents

Abstract

To provide a light quantity adjusting device, in which the accuracy of blade travel is improved and a blade drive speed is speeded up.SOLUTION: The light quantity adjusting device comprises: a bottom plate having an opening; an aperture blade for adjusting the quantity of light passing through the opening; a drive ring for driving the aperture blade; a presser plate for operably holding the aperture blade and the drive ring between the bottom plate and itself; and a ring-shaped sheet member arranged between the aperture blade and the drive ring. The drive ring includes a blade presser protruding toward the aperture blade side than a surface of the sheet member facing the aperture blade on the center side of the opening than the inside diameter of the ring-shaped sheet member and supporting the aperture blade between the bottom plate and itself.SELECTED DRAWING: Figure 7

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 a light amount adjusting device mounted on an optical device such as a camera or an interchangeable lens, it is required to increase the accuracy of the aperture diameter and increase the speed of the aperture drive. In the diaphragm device as the conventional light quantity adjusting device shown in Patent Document 1 and FIGS. 11 to 14, the drive ring is rotated around the fixed opening to rotate the plurality of diaphragm blades in the opening and closing direction, and the plurality of diaphragm blades. The amount of light is adjusted by changing the size of the formed aperture. Such a diaphragm device is also called an iris diaphragm device.

  As shown in FIG. 11 and FIG. 13, each diaphragm blade 210 is provided with a drive pin 211 and a cam pin 212 extending in opposite directions from the blade surface. The drive ring 220 shown in FIGS. 11 and 12 is formed with a plurality of drive holes 223 into which the drive pins 211 of the plurality of diaphragm blades 210 are respectively engaged.

  In the base plate 250 shown in FIG. 14, a fixed opening 254 is formed at the center with the optical axis 205 as the center, and a plurality of cams with which the cam pins 212 of the plurality of diaphragm blades 210 engage with each other around the fixed opening 254. A groove portion 251 is formed. The holding plate 240 has a fixed opening 244 formed in the center, is arranged so as to sandwich the plurality of diaphragm blades 210 and the drive ring 220 between the holding plate 250 and is fixed to the main plate 250.

  As described above, in the conventional diaphragm device, the plurality of diaphragm blades 210 are rotatably held by the fixed base plate 250 and the rotating drive ring 220. Further, the back side portion of the drive pin 211 on the blade surface of each diaphragm blade 210 on the ground plate 250 side is supported by the ground plate 250.

  Further, the peripheral portion on the back side of the cam pin 212 on the blade surface on the drive ring 220 side of each diaphragm blade 210 is supported by a blade support portion 228 formed on the drive ring 220 so as to extend radially outward. The blade support portions 228 are provided at a plurality of locations in the circumferential direction of the drive ring 220 in the vicinity of the drive holes 223. A connecting portion 221 extending in the circumferential direction is formed between the plurality of blade support portions 228 so as to form a continuous flange including the blade support portions 228. The surfaces of the plurality of blade support portions 228 and the connecting portion 221 on the base plate 250 side (the diaphragm blade side) are formed as one flat surface (flange surface).

  In addition, a cylindrical radial support portion 226 that protrudes toward the pressing plate 240 is formed on the inner peripheral side of the drive ring 220 having an opening 224 formed in the center, and an outer peripheral surface of the radial support portion 226 includes Protrusions 227 that rotatably contact the inner peripheral surface of the pressing plate 240 are formed at a plurality of locations in the circumferential direction.

JP-A-2-114246

  In the conventional diaphragm device configured as described above, the blade surface on the opposite side of the diaphragm blade 210 from the base plate 250 side is supported by the drive ring 220 that is a rotating member. The rotating drive ring 220 is configured to slide. In addition, the drive ring 220 is fitted in a state where there is a gap with the inner diameter of the holding plate 240, and the torque of the drive unit 201 is transmitted to the gear unit 225 of the drive ring 220 through the pinion gear 202, thereby driving the drive ring. 220 is rotated. In this case, if the drive ring 220 is heavy, it becomes a load during the diaphragm operation, and the drive speed becomes slow. Furthermore, when the drive ring 220 and the diaphragm blade 210 come into contact with each other and slide, the resistance increases and becomes a load.

  On the other hand, in another conventional example, as shown in the cross-sectional view of FIG. 15, the sheet member 370 is sandwiched between the drive ring 320 and the aperture blade 310 as a fixed member, and the drive ring is reduced and lightened. The load is being reduced. However, the travel space in the thickness direction of the diaphragm blades 310 is such that, in the small diaphragm state where the diaphragm blades 310 are arranged on the inner peripheral side of the drive ring 320, the upper surface of the base plate 350 and the lower surface of the drive ring 320, as indicated by reference numeral 381. Determined by the interval between. On the other hand, in the state in which the diaphragm in which the diaphragm blade 310 is disposed on the outer peripheral side of the drive ring 320 is opened, the traveling space in the thickness direction of the diaphragm blade 310 is between the base plate 350 and the sheet member 370 as indicated by reference numeral 380. It will be determined by the interval. Therefore, the blade traveling space 380 on the outer peripheral side and the blade traveling space 381 on the inner peripheral side are different, and there is a problem that the traveling accuracy of the blade is not stable. Moreover, there is a problem in that the traveling accuracy of the blades is further deteriorated depending on the difference in posture of the apparatus.

  The present invention has been made in view of the above-described problems, and an object thereof is to improve the traveling accuracy of the blades and increase the driving speed of the blades in the light amount adjusting device.

  The light amount adjusting device according to the present invention includes a base plate having an opening, a diaphragm blade that adjusts the amount of light passing through the opening, a drive ring that drives the diaphragm blade, and the base plate, and the diaphragm blade and the ground plate A holding plate that operably holds the drive ring, and a ring-shaped sheet member disposed between the aperture blade and the drive ring, wherein the drive ring is formed from an inner diameter of the ring-shaped sheet member. The blade member has a small outer shape, protrudes toward the diaphragm blade side from the surface of the sheet member facing the diaphragm blade, and has a blade pressing portion that supports the diaphragm blade with the base plate.

  According to the present invention, in the light amount adjusting device, it is possible to improve the traveling accuracy of the blade and increase the driving speed of the blade.

The disassembled perspective view which shows the structure of the aperture_diaphragm | restriction apparatus concerning one Embodiment of this invention. The perspective view which shows the state which assembled the diaphragm | throttle device of one Embodiment. The perspective view of the aperture blade in the aperture_diaphragm | restriction apparatus of one Embodiment. The perspective view of the surface of the drive ring in the diaphragm | throttle device of one Embodiment. The perspective view of the back surface of the drive ring in the diaphragm | throttle device of one Embodiment. The perspective view of the main plate in the diaphragm | throttle device of one Embodiment. The perspective view of the sheet | seat member in the aperture_diaphragm | restriction apparatus of one Embodiment. Sectional drawing of the aperture_diaphragm | restriction apparatus of one Embodiment. The top view which shows the state which opened the aperture blade in the aperture_diaphragm | restriction apparatus of one Embodiment. The top view which shows the state which narrowed down the aperture blade in the aperture_diaphragm | restriction apparatus of one Embodiment. The figure which shows the aperture blade of the modification of one Embodiment. The exploded perspective view of the conventional diaphragm | throttle device. The perspective view of the drive ring in the conventional diaphragm | throttle device. The perspective view of the aperture blade in the conventional aperture stop apparatus. The perspective view of the main plate in the conventional diaphragm | throttle device. Sectional drawing of another conventional aperture_diaphragm | restriction apparatus.

  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 of an iris diaphragm device 6 which is an embodiment of a light amount adjusting device of the present invention. FIG. 2 is a perspective view showing an assembled state of the diaphragm device 6 of the present embodiment. In this embodiment, the diaphragm device will be described, but a shutter device and a diaphragm device having a shutter function are also included in the light amount adjusting device of the present invention.

  1 and 2, the diaphragm device 6 includes an actuator 1, a holding plate 40, a drive ring 20, a plurality of diaphragm blades (light-shielding blades) 10, a ground plate (base member) 50, and a photo interrupter 3. Prepare.

  The actuator 1 is an electromagnetic actuator such as a stepping motor. A pinion gear 2 that rotates the drive ring 20 is attached to the output shaft of the actuator 1. The actuator 1 and the pinion gear 2 constitute a drive source unit.

  The photo interrupter 3 is used as a sensor for detecting the initial position of the drive ring 20. The actuator 1 is attached to the holding plate 40 with screws 61.

  The central axis 5 of the diaphragm device 6 coincides with the optical axis of the imaging device when the diaphragm device 6 is mounted on the imaging device. In the following description, a direction parallel to the central axis 5 is referred to as a thrust direction. The holding plate 40, the drive ring 20, the sheet member 70, the plurality of diaphragm blades 10, and the base plate 50 are stacked in this order in the thrust direction. That is, the drive ring 20 is disposed on the side opposite to the base plate 50 with respect to the aperture blade 10 in the thrust direction, and the holding plate 40 is disposed on the side opposite to the base plate 50 with respect to the aperture blade 10 and the drive ring 20. The The aperture blade 10 and the drive ring 20 are operably held by the main plate 50 and the pressing plate 40. A direction and a surface orthogonal to the thrust direction are referred to as a radial direction (radial direction) and a radial surface, respectively.

  A plurality of aperture blades 10 are arranged in the circumferential direction of the fixed opening 54 formed in the main plate 50. In this embodiment, nine diaphragm blades 10 are used. The number of diaphragm blades is not limited to nine, and may be other plural sheets.

  FIG. 3 is an enlarged view of one aperture blade 10. The diaphragm blade 10 is arranged so as to be substantially parallel to the radial surface, and has a flat plate-shaped blade portion 10a having a light shielding function, and a drive pin 11 provided so as to protrude from the blade portion 10a to opposite sides in the thrust direction. And a cam pin 12. The positions of the drive pin 11 and the cam pin 12 in the radial plane are different from each other.

  4A is an enlarged view of the drive ring 20, and FIG. 4B is a view of the drive ring 20 of FIG. 4A viewed from the back side. The drive ring 20 has a light passage opening 24 at the center thereof, and further has blade support protrusions 22 as first blade support portions provided at a plurality of circumferential positions (9 places) around the light passage opening 24. , And nine connecting portions 21 formed in a ring shape so as to connect the nine blade support protrusions 22 in the circumferential direction. Each blade support protrusion 22 is formed to protrude radially outward from the connecting portion 21. The nine blade support protrusions 22 are formed with drive holes 23 into which the drive pins 11 of the nine aperture blades 10 are inserted and engaged.

  A gear portion 25 that meshes with the pinion gear 2 is formed on a part of the outer peripheral portion of the drive ring 20. The gear portion 25 extends in an arc shape in the circumferential direction and has a plurality of gear teeth formed on the outer periphery thereof. The gear portion 25 extends radially outward from the connecting portion 21 and is connected to the gear tooth portion 25a to be connected to the gear teeth. It is comprised by the two gear support | pillar parts 31 which form a space between the part 25a and the connection part 21. FIG. The gear support 31 is formed with a drive hole 23 into which the drive pins 11 of the two diaphragm blades 10 are inserted. That is, the gear support 31 also serves as two of the nine drive holes 23.

  In addition, radial support wall portions 26 extending from the connection portion 21 toward the holding plate 40 in the thrust direction are formed at a plurality of circumferential locations (9 locations in the present embodiment) in the connection portion 21 of the drive ring 20. . A radial support wall portion 26 of the drive ring 20 is fitted to the inner peripheral portion of the pressing plate 40 and is supported rotatably around the central axis 5.

  Further, thrust pressing protrusions 29 are provided on the front and back of a plurality of circumferential positions (9 positions in the present embodiment) on the pressing plate 40 side in the connecting portion 21 of the drive ring 20. A ring-shaped sheet member 70 rides on the thrust retainer protrusion 52 of the base plate 50, and the thrust retainer protrusion 29 of the drive ring 20 is sandwiched between the sheet member 70 and the retainer plate 40, so that the drive ring 20 can be rotated by the retainer plate 40. Supported in the thrust direction.

  Further, at one place in the circumferential direction of the drive ring 20, there is provided a light shielding protrusion 30 that enters between the light emitting portion and the light receiving portion of the photo interrupter 3 and shields light.

  As shown in FIG. 4B, a blade pressing portion 32 is formed on the back surface of the drive ring 20. The blade pressing portion 32 will be described in detail later.

  As shown in FIG. 1, the pressing plate 40 is formed in a ring shape having a light passage opening 44 in the center thereof, and covers (presses) the diaphragm blades 10 and the drive ring 20 disposed on the main plate 50. The base plate 50 is fixed with six screws 60.

  FIG. 5 is a perspective view showing the shape of the main plate 50. The base plate 50 is formed in a ring shape having a light passage opening 54 as a fixed opening at the center thereof, and a plurality of (the diaphragm blades 10) with which the cam pins 12 of the plurality of diaphragm blades 10 are respectively engaged. 9) cam groove portions 51 are formed.

  Further, a sheet member 70 shown in FIG. 6 is provided on the blade surface side of the main plate 50 and the blade surface side of the drive ring 20 so that the drive ring can be made small.

  In the present embodiment, “supporting (or pressing)” the diaphragm blades 10 gives the backlash necessary for smooth rotation of the diaphragm blades 10, and the diaphragm blades 10 rattle or drop more than that. This means that the movement is restricted so that it does not occur. That is, it is not pressing so that there is no backlash in a direction other than the rotating direction (thrust direction).

  In the diaphragm device 6 configured as described above, when the actuator 1 operates and the pinion gear 2 rotates, the drive ring 20 rotates around the central axis 5 with respect to the main plate 50 and the pressing plate 40. The drive ring 20 transmits the driving force from the actuator 1 to the nine aperture blades 10 via the drive pins 11. As a result, each diaphragm blade 10 rotates about the drive pin 11 as the cam pin 12 moves along the cam groove 51. By controlling the rotational position of the drive ring 20 by the actuator 1, the rotational position of the plurality of diaphragm blades 10, that is, the size (diameter) of the diaphragm opening formed by the blade portions 10 a of the plurality of diaphragm blades 10 is controlled. The The amount of light passing through the light passage openings 44, 24, 54 can be changed (adjusted) according to the aperture diameter.

  The detection of the initial rotation position of the drive ring 20 necessary for controlling the rotation position of the drive ring 20 is performed by the light-shielding protrusion 30 of the drive ring 20 entering between the light emitting part and the light receiving part of the photo interrupter 3. This can be done by detecting a signal indicating that light from the light is blocked.

  Next, a more characteristic configuration of the diaphragm device 6 of the present embodiment configured as described above will be described.

  Conventionally, as shown in FIG. 15, the blade travel space 380 on the outer peripheral side is determined by the space formed by the sheet member 370 and the base plate 350. At this time, the drive ring 320 is supported so as to be sandwiched between the sheet member 370 supported by the base plate 350 and the pressing plate 340 and the pressing plate 340. As a result, the blade travel space 381 on the inner peripheral side of the sheet member 370 is wider than the blade travel space 380 on the outer peripheral side of the sheet member 370 by the thickness of the sheet member 370.

  On the other hand, in the aperture device 6 of the present embodiment, the blade travel space 81 on the inner peripheral side is determined by the space formed by the drive ring 20 and the main plate 50 as shown in FIG. However, the drive ring 20 is formed with a blade pressing portion 32 that protrudes downward in the drawing inside the opening 70 a of the sheet member 70. The blade pressing portion 32 has an outer diameter smaller than the inner diameter of the ring-shaped sheet member 70, and is closer to the center side of the opening 70 a than the inner diameter of the sheet member 70 than the surface facing the aperture blade of the sheet member 70. Also protrudes to the aperture blade side. More specifically, the blade pressing portion 32 protrudes downward from the lower surface of the seat 70 by the dimension indicated by d, and the blade travel space 81 on the inner peripheral side of the seat 70 is defined on the outer peripheral side of the seat 70. It is smaller than the blade travel space 80. The dimension d corresponds to, for example, the thickness of one to several diaphragm blades 10. As described above, the interval between the blade pressing portion 32 and the main plate 50 of the drive ring 20 is made narrower than the interval between the sheet 70 and the main plate 50, and the interval between the blade pressing portion 32 and the main plate 50 is set. Define the blade travel space. As a result, as shown in FIGS. 8 and 9, the travel space of the diaphragm blade 10 is always defined by the interval between the blade pressing portion 32 and the main plate 50 regardless of whether the diaphragm blade 10 is in the open state or the small diaphragm state. It can always be supported stably. Further, since the change in the travel space of the diaphragm blade 10 due to the difference in posture is small, the change in accuracy can be reduced.

  Furthermore, by providing the sheet member 70 on the outer periphery of the drive ring 20, the drive ring 20 can be made smaller, and the speed can be increased and the accuracy can be improved.

  FIG. 10 is a diagram illustrating a diaphragm blade 410 according to a modification of the embodiment. In this modification, instead of providing the cam groove 51 on the base plate 50, a cam pin is provided, and the cam groove 412 is provided on the aperture blade 410 side. Even with such a configuration, the same effects as those of the above-described embodiment can be obtained.

  As described above, according to the above-described embodiment, the drive ring 20 can be reduced by the presence of the sheet member 70, and the contact area between the aperture blade 10 and the drive ring 20 can be reduced. As a result, the frictional resistance received by the diaphragm blade 10 can be reduced and the diaphragm blade 10 can be smoothly rotated, so that high-speed response can be improved. Furthermore, since the travel space of the blades can always be determined by the base plate 50 and the blade pressing portion 32 of the drive ring 20, changes in the travel space of the blades can be reduced, and the drive accuracy of the blades can be stabilized.

1: Actuator 2: Pinion gear 3: Photo interrupter 10: Diaphragm blade 20: Drive ring 40: Holding plate 50: Base plate 70: Sheet member

Claims (5)

A main plate having an opening;
A diaphragm blade for adjusting the amount of light passing through the opening;
A drive ring for driving the diaphragm blades;
A holding plate that operably holds the diaphragm blade and the drive ring between the base plate,
A ring-shaped sheet member disposed between the diaphragm blades and the drive ring,
The drive ring protrudes closer to the diaphragm blade side than the surface of the sheet member facing the diaphragm blades at the center side of the opening with respect to the inner diameter of the ring-shaped sheet member, and the diaphragm blades between the drive ring and the base plate A light quantity adjusting device having a blade pressing portion for supporting the light.   The light quantity adjusting device according to claim 1, wherein a travel space of the diaphragm blades is defined by an interval between the blade pressing portion and the base plate.   The light amount adjusting device according to claim 1, wherein the drive ring is supported by being sandwiched between the sheet member and the pressing plate.   The blade pressing portion protrudes from the surface of the sheet member facing the diaphragm blade so as to approach the base plate by an amount corresponding to the thickness of one to several sheets of the diaphragm blade. The light quantity adjusting device according to any one of claims 1 to 3.   The light quantity adjusting device according to claim 1, wherein the diaphragm blade has a cam pin or a cam groove portion.