JP2013218205A - Exposure adjustment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure adjustment device able to maintain the correct shape of a diaphragm aperture by restricting deformation of the shape of the diaphragm aperture.SOLUTION: An exposure adjustment device comprise: a plurality of blade members 14, each of which is provided with a shaft hole 14a serving as the center of rotation, and a conical projection 14b reciprocally rotated with respect to the shaft hole; a frame member 10 having an opening 10f, and shafts 10g interspatially formed outside the opening so as to surround the opening and fitted in the shaft holes 14a; a rotary drive member 13, reciprocally rotated around the center of an opening 13f, which has a plurality of cam grooves 13a interspatially arranged outside the opening 13f in order to rotate the blade members around the shaft hole 14a and which are formed from a pair of opposite inclined faces 13h decreased in its width in linear proportion to the depth direction from a mouth in order that the conical projection fits in it; and an urging member 18a configured to urge the conical projection in a direction parallel to the center O of rotation so that the conical projection is moved into the cam groove.

Description

  The present invention relates to an exposure adjustment apparatus, and more particularly to an exposure adjustment apparatus provided in an optical system in an optical apparatus such as a photographing apparatus or an image display apparatus.

  2. Description of the Related Art Conventionally, an exposure amount adjustment device for adjusting the amount of light passing through an optical system is generally provided in an optical system in an optical apparatus such as a camera or other imaging device or an image display device such as a projector. is there.

  Various forms of this exposure amount adjusting apparatus have been put into practical use. For example, a wide variety of so-called iris-type exposure amount adjustment devices (also referred to as aperture devices) are configured in which a plurality of thin plate members (referred to as aperture blades) are overlapped and the aperture size is adjusted by switching the overlap amount. In addition, various proposals have been made by, for example, Japanese Patent Laid-Open Nos. 2-10336 and 2003-5248.

  A conventional iris-type exposure amount adjusting device includes, for example, a plurality of diaphragm blades each provided with a pin-shaped operating shaft, and a rotary drive member formed with a plurality of cam grooves with which each operating shaft of the diaphragm blade is engaged. When the rotary drive member is rotated, the cam groove of the rotary drive member acts on the operating shaft of the aperture blade to swing the aperture blade. With such a configuration, aperture size adjustment is performed for a polygonal aperture formed by a plurality of aperture blades.

  In the exposure amount adjusting apparatus having such a configuration, the operating shaft and the cam are arranged so that the operating shaft can smoothly slide and move along the cam groove with the operating shaft engaged with the cam groove. It is configured to have a slight gap between the grooves.

Japanese Patent Laid-Open No. 2-10336 JP 2003-5248 A

  However, in the conventional exposure adjustment apparatus, if there is a gap between the operating shaft and the cam groove, an operation error of the aperture blade may occur. This is because the lengths of the sides of the polygon formed by the diaphragm blades are different from each other, and the aperture shape of the aperture is collapsed, so that a regular polygonal aperture cannot be obtained. Effect. In particular, the collapse of the aperture shape when the aperture is set to a small diameter aperture has a problem of greatly affecting the exposure accuracy.

  In addition, since the aperture shape affects the degree of blurring of the image, there is a problem that when the aperture aperture shape is collapsed, an image that does not look good is generated.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide an exposure amount adjusting device capable of suppressing the collapse of the aperture opening shape and always maintaining an accurate aperture aperture shape. Is to provide.

  In order to achieve the above object, an exposure amount adjusting apparatus according to one aspect of the present invention is a conical or spherical shape that reciprocally rotates around a shaft hole or a shaft portion that serves as a rotation center in the exposure amount adjustment device. A plurality of blade members each provided with a convex portion, and an opening and a shaft or hole that is formed on the outside of the opening so as to surround the opening and that is spaced apart from each other and that fits the shaft portion or the shaft portion. A frame member having a conical shape or a spherical convex portion, which is arranged on the outer side of the opening so as to surround the opening, and the conical or spherical convex portions are fitted to rotate the frame member and the plurality of blade members with respect to the rotation center. A rotation drive member that has a plurality of cam grooves each having a pair of inclined surfaces that are linearly proportional to the depth direction from the mouth and that are opposed to each other, and that reciprocates around the center of the opening; Protrusion of the serial spherical in the center of rotation parallel to the direction to face the inside of the cam groove, and and a biasing member for biasing the projection portion of the conical or above spherical.

  ADVANTAGE OF THE INVENTION According to this invention, the exposure amount adjustment apparatus which can suppress collapse of a diaphragm aperture shape and can always maintain an exact diaphragm aperture shape can be provided.

1 is an exploded perspective view of an exposure adjustment apparatus according to an embodiment of the present invention. FIG. 1 is a cross-sectional view of the exposure amount adjusting device of FIG. Sectional drawing which abbreviate | omits a part of exposure amount adjustment apparatus of FIG. 1, and shows a principal part Sectional drawing which shows the modification of the exposure amount adjustment apparatus of FIG. Sectional drawing which abbreviate | omits a part of exposure amount adjustment apparatus of FIG. 4, and shows a principal part

  The present invention will be described below with reference to the illustrated embodiments.

  1-3 is a figure which shows one Embodiment of this invention. Among these, FIG. 1 is an exploded perspective view showing an exposure adjustment apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the exposure adjustment apparatus of FIG. FIG. 3 is a cross-sectional view showing a main part of the exposure adjustment apparatus of FIG. 1 with some members omitted.

  An exposure amount adjusting apparatus according to an embodiment of the present invention photoelectrically converts an optical image formed by, for example, an optical lens using a solid-state imaging device, and digital image data representing a still image or a moving image from an image signal obtained thereby. The digital data thus generated is recorded on a recording medium, and a still image or a moving image can be reproduced and displayed on a display device based on the digital image data recorded on the recording medium. The present invention is applied to a photographic lens barrel that is integrally or detachably provided in a photographic device (camera), and exemplifies a so-called iris-type exposure adjustment device (aperture device). is there.

  In each drawing used for the following description, each component may be shown with a different scale in order to make each component large enough to be recognized on the drawing. Therefore, according to the present invention, the number of constituent elements, the shape of the constituent elements, the ratio of the constituent element sizes, and the relative positional relationship of the constituent elements described in these drawings are limited to the illustrated embodiments. It is not a thing.

  In the present embodiment, the central axis of the opening for allowing the light beam to pass is denoted by reference symbol O. The central axis O coincides with the optical axis of the photographing optical system in the photographing lens barrel of the photographing apparatus to which the exposure adjustment device of the present embodiment is applied. In the direction along the central axis O, the light incident side (for example, the subject side facing the front of the photographing apparatus; the left hand side in FIG. 1) is the front, and the light emitting side (near the rear surface of the photographing apparatus). The light receiving surface side of the arranged image sensor is referred to as the rear.

  The structure of the exposure adjustment apparatus 1 of this embodiment is demonstrated below using FIGS. 1-3. The exposure amount adjusting apparatus 1 includes a front holding member 10, a rear holding member 11, a drive motor 12 as a drive source, a rotary drive member 13, a diaphragm blade member 14, a driving two-stage gear 15, The coil spring 16, the sliding plate 17, the plate-like urging member 18, and the rotational position detection sensor 19 are mainly configured.

  The front-side holding member 10 and the rear-side holding member 11 constitute a casing of the exposure amount adjusting device 1, and the various constituent members are housed and disposed inside the casing. The front holding member 10 and the rear holding member 11 are integrated by three screws 11a. That is, the screw 11 a is inserted through the hole formed in the fixing tab 11 c of the rear holding member 11 and screwed into the screw hole formed in the fixing portion 10 c of the front holding member 10. The front holding member 10 and the rear holding member 11 thus integrated are formed in a substantially annular shape having, for example, a circular opening (10f, 11f) at a substantially central portion. The rear holding member 11 has a plurality of short spacing pins 11d extending in a direction parallel to the optical axis around the opening 11f. When the rotation driving member 13 is housed in the recess 10i of the front holding member 10 and the rotation driving member 13 is sandwiched between the front holding member 10 and the rear holding member 11, the spacing pin 10d rotates together with the concave surface 10h. This is to secure a necessary space in the optical axis direction so that the driving member 13 can rotate to the center of the opening 10f or the like (optical axis) in the recess 10i and prevent it from moving unnecessarily in the optical axis direction. is there. That is, the distance from the concave surface 10 h to the tip of the spacing pin 11 d is only slightly larger than the thickness dimension of the rotation driving member 13.

  A motor fixing portion 10a that fixes and supports the drive motor 12 that is a driving source is formed on a part of the outer peripheral edge portion of the front holding member 10 so as to protrude outward from a part of the annular shape portion. . The motor fixing portion 10a is formed with a hole portion 10b through which the drive shaft of the drive motor 12 is inserted and a screw hole 10e for screwing and fixing the fixing tab 12a of the drive motor 12. With this configuration, after the drive shaft (not shown) of the drive motor 12 is inserted into the hole 10b of the motor fixing portion 10a, one end surface of the drive motor 12 is brought into close contact with the motor fixing portion 10a in the optical axis direction. The screw 12b is screwed into the screw hole 10e through the hole of the fixing tab 12a. Thereby, the drive motor 12 is fixed to the front holding member 10.

  As described above, the front holding member 10 is a frame member that is formed in a substantially annular shape as a whole and has an opening 10f at a substantially central portion. The front holding member 10 that is a frame member is fitted into a rotation shaft hole 14a of a diaphragm blade member 14 to be described later, and a plurality of shafts 10g (not shown in FIG. 1) serving as the rotation center of the diaphragm blade member 14. 2 and 3). The shaft 10g is located outside the opening 10f (annular portion), concentrically surrounding the opening 10f, and at a position spaced apart from each other at a predetermined interval in the circumferential direction. The same number as the blade members 14; seven in this embodiment) is provided. The plurality of shafts 10g are planted from the inner surface (one surface, one end surface) of the front holding member 10 toward the rear (rear holding member 11 side) in a direction parallel to the central axis O of the opening 10f. Further, in order to hold a rotation driving member 13 (described later) rotatably on the inner surface, a concave portion 10i having a substantially ring-shaped concave surface 10h (see FIG. 2) recessed in the optical axis direction so as to surround the opening 10f is formed. (Not shown). The outer periphery excluding a part of the rotational drive member 13 is fitted into a ring-shaped circumferential inner surface formed on the circumference of the concave portion 10i so that the rotational drive member 13 can reciprocate around the optical axis in the concave portion 10i. It is paid.

  In the present embodiment, the front holding member 10 is provided with a shaft 10g, and the rotation shaft hole 14a of the diaphragm blade member 14 is fitted to the shaft 10g. However, the present invention is not limited to this configuration. You may comprise so that a shaft part may be formed in the front side holding member 10 so that a rotational shaft part may be planted in the aperture blade member 14, and it may be fitted to this.

  For example, a stepping motor or the like is applied to the drive motor 12 that is a drive source of the exposure adjusting apparatus 1. A pinion gear 12 c is fixed to one end of the drive shaft of the drive motor 12. The pinion gear 12 c meshes with the large gear of the driving two-stage gear 15. Further, a small gear (not shown in FIG. 1) of the driving two-stage gear 15 meshes with a gear portion 13 c formed at a part of the outer peripheral edge portion of the rotation driving member 13. With this configuration, when the drive motor 12 is rotationally driven, the driving force is transmitted to the rotational drive member 13 via the pinion gear 12 c and the driving two-stage gear 15. Thereby, the rotation drive member 13 is configured to be rotatable forward and backward around the central axis O.

  The rotation drive member 13 is a drive member that rotates the plurality of blade members 14 with respect to the rotation center (rotation axis O). For this purpose, the rotation driving member 13 is constituted by a thin plate member formed in a substantially annular shape having, for example, a circular opening 13f in a substantially central portion. In addition to the gear portion 13c described above, a rotational position detecting arm portion 13b, a spring hanging portion 13d on which one end of the coil spring 16 is hung, and the like are formed on a part of the outer peripheral edge portion of the rotation driving member 13. . The gear portion 13c is a portion that receives the driving force from the driving motor 12 by meshing with the small gear (not shown) of the driving two-stage gear 15 as described above. The arm portion 13b for detecting the rotational position is a part that functions as a position detection unit that detects the rotational position of the rotation driving member 13 in conjunction with the rotational position detection sensor 19. In addition, as the rotation position detection sensor 19, an optical position sensor (Position Sensitive Detector) etc. are applied, for example. The spring hanging portion 13d is a portion where one end of a coil spring 16 having an elastic force for biasing the rotation driving member 13 in one direction around the rotation axis O is hung. Further, the other end of the coil spring 16 is hung on a spring hanging portion 10 d of the front holding member 10. Therefore, with this configuration, the rotational driving member 13 is always applied with the elastic force by the coil spring 16 around the central axis O and in the direction of the arrow R in FIG. In this case, the rotational drive member 13 itself is engaged with the gear portion 13c and the small gear (not shown) of the drive two-stage gear 15 as described above, so that the detent torque of the drive motor 12 acts. The coil spring 16 is configured not to rotate more than a predetermined amount against the elastic force of the coil spring 16.

  Further, a plurality (the same number as the diaphragm blade members 14; seven in the present embodiment) are provided at positions outside the opening 13f of the rotation driving member 13 (annular portion) so as to surround the opening 13f and are spaced apart from each other at a predetermined interval. ) Cam groove 13a. The plurality of cam grooves 13a are through grooves formed in a predetermined shape in a plane orthogonal to the central axis O in the outer portion (annular portion) of the opening 13f. In the plurality of cam grooves 13a, conical convex portions 14b, which are operating shafts of a diaphragm blade member 14 to be described later, are fitted. For this purpose, the plurality of cam grooves 13a are linearly proportional in the depth direction from the mouth 13aa (see FIG. 3) and have a pair of slopes 13h that are opposed to each other, and the cross-sections are so-called slopes. Is formed. In accordance with this, the cross section of the conical convex portion 14b is formed by a slope 14h (see FIG. 3) having an angle substantially similar to the pair of slopes 13h.

  The outer diameter of the rotary drive member 13 is set to be smaller than the diameter of a concentric circle formed by connecting the plurality of shafts 10g in the circumferential direction. With such a configuration, the rotation drive member 13 can freely rotate forward and backward (reciprocating) with respect to the central axis O of the opening 13f.

  As described above, the plurality of diaphragm blade members 14 are fitted to the shaft 10g of the front holding member 10 to be the rotation shaft hole 14a, and the reciprocating rotation (swinging) with respect to the rotation shaft hole 14a. A conical convex portion 14b that moves), and a pressed convex portion 14c that is formed back to back on the back side of the conical convex portion 14b and has a spherical tip, and is entirely formed by a thin plate-shaped light shielding member. Yes. In addition, the diaphragm blade member 14 in this embodiment has shown the example made into seven sheets structure.

  The conical convex portion 14b formed on each of the plurality of diaphragm blade members 14 is integrated with the thin plate member forming the main part of the diaphragm blade member 14 by, for example, resin molding or by means such as caulking. Is formed.

  Further, in the plurality of diaphragm blade members 14, the conical convex portion 14 b has a back surface side portion (a portion that is back-to-back across the 14 thin plate-like members) in the protruding direction (rear) of the conical convex portion 14 b. There is provided a pressed protrusion 14c formed so as to protrude toward the opposite side (front).

  The plate-like urging member 18 is a urging member having a single plate shape provided to prevent the conical protrusion 14b and the cam groove 13a from being disengaged. The plate-like urging member 18 is formed in a substantially annular shape having, for example, a circular opening 18f at a substantially central portion by a thin plate-like member having elasticity as a whole, for example, a stainless plate, a resin molded plate member or the like. A plurality of spring portions 18b (the same number as the aperture blade members 14) are formed at positions spaced apart from each other with a predetermined interval so as to surround the opening 18f. The spring portion 18b is formed in the shape of a section formed in a cantilever shape by cutting out the periphery of the spring portion 18b on the outer peripheral side of the opening 18f. This section shape has a beam portion 18c that elastically deforms by extending from the fixed end of the spring portion 18b along the circumference of the opening 18f, and a pressing portion 18d that extends radially from the tip of the beam portion 18c toward the center of the opening 18f. Consists of. The pressing portion 18d, which is in the vicinity of the distal end portion of the spring portion 18b, is configured to be elastically movable (displaceable) in the rotation center of the rotation drive member 13, that is, in a direction along the central axis O (a direction parallel to the rotation center). Yes.

  When the exposure amount adjusting device 1 is assembled, the pressing portions 18d of the spring portions 18b come into contact with the pressed convex portions 14c of the diaphragm blades 14 as shown in FIGS. The conical convex portion 14b is urged in a direction parallel to the central axis O so that the convex portion 14b is directed into the cam groove 13a.

  A sliding plate 17 is disposed between the plurality of blade members 14 and the plate-like urging member 18. The sliding plate 17 is a thin plate-like member whose surface is formed with slidability, and is a substantially ring-shaped member formed with a circular opening 17f, for example, in a substantially central portion. The sliding plate 17 is formed with a plurality of holes 17a and long holes 17b (the same number as the aperture blade member 14) at positions spaced apart from each other by a predetermined distance so as to surround the opening 17f. Spacing pins 11d are fitted in the respective holes 17a, the diameters of the respective holes 17a are larger than the diameters of the spacing pins 11d, the respective holes 17a are formed as escape holes, and the elongated projections 14c ( The spring portion 18b) is loosely fitted in the same manner, and each elongated hole 17b is formed as a relief hole. By providing the sliding plate 17, the plurality of blade members 14 are smoothly swung between the rotation driving member 13 and the plate-like urging member 18.

  As described above, according to the above-described embodiment, the plurality of diaphragm blade members 14 each have the conical convex portion 14 b that is the operating shaft, and each conical convex portion 14 b is the plurality of cams of the rotation driving member 13. It fits in each groove 13a. At this time, the conical convex portion 14b is directed in a direction parallel to the rotation center axis O so as to always go into the cam groove 13a by the pressing portion 18d at the tip of the spring portion 18b provided on the biasing member 18. Energized.

  Therefore, with this configuration, the conical convex portion 14b, which is the operating shaft of the diaphragm blade member 14, is always fitted into the cam groove 13a of the rotation drive member 13 without a gap, so that the rotation drive member 13 is moved in both forward and reverse directions. Even if the diaphragm blade member 14 is driven to swing by being rotated, an accurate diaphragm shape can be secured without play.

  In the above-described embodiment, an example in which the conical convex portion 14 b is used as the operating shaft of the diaphragm blade member 14 is shown. As described above, the conical convex portion 14b is always urged in the direction parallel to the central axis O by the spring portion 18b of the urging member 18, so that the conical convex portion 14b is always directed toward the cam groove 13a. And the conical convex part 14b is reliably inserted into the cam groove 13a. Therefore, it is only necessary to ensure that the convex portion (14b) as the operating shaft is fitted into the cam groove 13a, and the shape of the convex portion is limited to the shape shown in the above embodiment. Is not something

  For example, in the modification shown in FIGS. 4 and 5, the operating shaft of the aperture spring member 14 </ b> A having a different shape is used instead of the conical convex portion 14 b in the aperture spring member 14 of the exposure adjusting device of the above embodiment. For example, a spherical convex portion 14Ab is shown.

  In the case of this configuration, the spherical convex portion 14Ab is always directed into the cam groove 13a by the urging force in the direction parallel to the central axis O by the spring portion 18b of the urging member 18 as in the above-described embodiment. Be energized as At this time, the spherical convex portion 14Ab is urged against the pair of inclined surfaces 13h of the cam groove 13a by point contact. Therefore, the load caused by unnecessary frictional force on the spherical convex portion 14Ab and the cam groove 13a is reduced. In addition, the fitting state of the spherical convex portion 14Ab into the cam groove 13a is always reliably maintained without backlash, and the spherical convex portion 14Ab slides in the cam groove 13a as the rotational drive member 13 rotates forward and backward. Smooth movement can be ensured even when moving. Therefore, the shape of the aperture opening formed by the aperture blade member 14 is not destroyed.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and applications can of course be implemented without departing from the spirit of the invention. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if several constituent requirements are deleted from all the constituent requirements shown in the above-described embodiment, if the problem to be solved by the invention can be solved and the effect of the invention can be obtained, this constituent requirement is deleted. The configured structure can be extracted as an invention.

  The present invention uses an electronic device having a photographing function, such as a digital camera, a mobile phone, a sound reproducing device, a recording device, an electronic notebook, an electronic dictionary, a personal computer, a game device, a television, a clock, and a GPS (Global Positioning System). The present invention can be widely applied to exposure amount adjusting devices in various electronic devices such as navigation devices.

  Furthermore, the present invention is similarly applied to an exposure adjustment device in an electronic device having a function of acquiring an image using an imaging element and displaying the acquired image on a display device, for example, an observation device such as a telescope, binoculars, and a microscope. it can.

  In addition to these, the exposure amount adjusting apparatus according to the present invention can be applied to a projection type image display apparatus that projects an image using, for example, a transmissive liquid crystal display apparatus.

1 ... Exposure amount adjustment device,
10: Front holding member, 10a: Motor fixing part, 10f: Opening, 10g ... Shaft, 10h ... Concave surface, 10i ... Concave part,
11: Rear holding member, 11d: Spacer pin,
12 ... Drive motor, 12c ... Pinion gear,
13 …… Rotation drive member, 13a …… Cam groove, 13aa …… Mouth, 13b …… Arm part, 13c …… Gear part, 13d …… Spring hanging part, 13f …… Opening, 13h …… Slope,
14, 14 </ b> A... Diaphragm blade member, 14 a... Rotation shaft hole, 14 b... Conical convex portion, 14 Ab .. spherical convex portion, 14 c .. pressed convex portion, 14 h.
15 …… Two-stage gear for driving, 16 …… Coil spring,
17 ... sliding plate, 17f ... opening,
18 …… Plate-like biasing member, 18b …… Spring part, 18f …… Opening,
19 …… Rotation position detection sensor

Claims (3)

In the exposure adjustment device,
A plurality of blade members each provided with a shaft hole or a shaft portion for becoming a rotation center, and a conical or spherical convex portion reciprocatingly rotated about the rotation center;
A frame member having an opening and a shaft or hole that is formed on the outside of the opening so as to surround the opening and are spaced apart from each other;
In order to rotate the plurality of blade members with respect to the rotation center, the blade members are arranged outside the opening so as to surround the opening, and the conical or spherical convex portions are inserted from the mouth to fit. A rotation drive member that has a plurality of cam grooves each having a pair of inclined surfaces that are linearly proportional to the depth direction and have a width that is opposed to each other and that reciprocally rotates about the center of the opening;
An urging member that urges the conical or spherical convex portion in a direction parallel to the rotation center so that the conical or spherical convex portion is directed into the cam groove;
An exposure adjustment apparatus comprising:   2. The exposure adjustment apparatus according to claim 1, wherein the urging member is plate-shaped, and each of the plurality of spring portions formed on the urging member urges each of the plurality of blade members.   3. The exposure amount adjustment according to claim 2, wherein the urging member has a single plate shape, has an opening in the center, and the spring portions are formed around the opening so as to be separated from each other. apparatus.

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