JP4954553B2 - Light amount adjusting device and camera - Google Patents

Description

  The present invention relates to a shutter and diaphragm light amount adjusting device and a camera used in an optical apparatus such as a digital still camera.

  In recent years, products such as video cameras and still cameras that require a light amount adjusting device are strongly required to be small and thin, and inevitably light amount adjusting devices such as electromagnetically driven shutters and diaphragms are also made small and thin. There is a request. An example of the light amount adjusting device is disclosed in Japanese Patent Laid-Open No. 5-216090 (Patent Document 1).

In the downsizing, since the mechanism such as the light amount adjusting device and autofocus is housed in the gap between the optical member and the inside of the lens barrel holding the optical member, these are placed in a cylinder as small as possible centering on the optical axis. This is because of the desire to contain the member. In addition, since the distance from the shutter member or the diaphragm member to the image pickup device such as a CCD or the distance from the driving source for autofocusing is reduced, the above-described thinning reduces the dimension in the optical axis direction of the light amount adjusting device. This is because of the desire to do.
Japanese Patent Laid-Open No. 5-216090

  The electromagnetically driven shutter, which is an example of the light amount adjusting device proposed above, includes two blades, a blade pressing member, a shutter base plate, a winding coil, and a magnet. The two blades are sandwiched between the blade retainer plate and the shutter base plate, and the winding coil and the magnet are sandwiched between the shutter base plate and the stator. That is, the two blades, the winding coil, and the magnet are held in a space formed by a combination of different members. Therefore, in the light amount adjusting device disclosed in Patent Document 1, the thickness of the entire light amount adjusting device is increased, and the thickness reduction is not sufficient. Further, as described above, since the blade is sandwiched between the blade pressing plate and the shutter base plate, it cannot be said that the size reduction is sufficient.

(Object of invention)
The present invention is intended to provide a light amount adjusting device and a camera that can achieve a reduction in size and thickness.

To achieve the above object, the present invention provides a shielding member that shields incident light, a pressing member that covers the shielding member, a ground plate that rotatably holds the shielding member together with the pressing member, and the shielding member. In the light amount adjusting device having a driving means for driving, the pressing member has a traveling rail portion that guides the rotation of the shielding member at an end portion, and the traveling rail portion is disposed at a distal end of the shielding member. The light quantity adjusting device has an engaging portion formed so as to be sandwiched , and the shielding member and the driving means are arranged between the base plate and the pressing member.

  Similarly, in order to achieve the above object, the camera is provided with the above light amount adjusting device.

  ADVANTAGE OF THE INVENTION According to this invention, the light quantity adjustment apparatus or camera which can achieve size reduction and thickness reduction can be provided.

  The best mode for carrying out the present invention is as shown in Examples 1 to 3 described below.

  Hereinafter, an electromagnetically driven shutter according to Example 1 of the present invention will be described with reference to the drawings. 1 is an exploded perspective view of an electromagnetically driven shutter, FIG. 2 is a plan view of the electromagnetically driven shutter, and FIGS. 3 and 4 are cross-sectional views cut along different portions of the electromagnetically driven shutter shown in FIGS. . FIG. 5 is a schematic view of a digital zoom camera (photographing apparatus) provided with the electromagnetically driven shutter of FIGS.

  First, a digital camera including an electromagnetically driven shutter according to the first embodiment will be described with reference to FIG. In FIG. 5, reference numeral 11 denotes a camera body, in which a lens group 12 and the like which will be described later are arranged. Reference numeral 12 denotes a lens group disposed in the lens barrel. An electromagnetically driven shutter 13 is also disposed in the lens barrel and blocks subject light that has passed through the lens 11. Reference numeral 14 denotes an image pickup element which is an image pickup medium that receives (exposes) a subject light flux that has passed through the lens group 12, and is a CCD, a C-MOS, or a film.

  Next, the configuration of the electromagnetically driven shutter 13 will be described with reference to FIG. In FIG. 1, 1 is a magnet base plate. Reference numeral 2 denotes a permanent magnet that is a rotor, and magnetized portions (N, S) magnetized in two poles are formed on the outer peripheral surface thereof. Reference numeral 3 denotes a shutter blade having rotating shafts 3a and 3b serving as bearings, and the permanent magnet 2 is integrally arranged by insert molding, two-color molding, or separate molding and press-fitting. Here, as shown in FIG. 4, the rotary shafts 3a and 3b are rotatably fitted and held in a blade rotation bearing hole 1a of the magnet base plate 1 and a blade rotation bearing hole 6a of a blade presser plate 6 described later. .

  Reference numeral 4 denotes a horseshoe-shaped stator yoke made of a soft magnetic material, and the stator yoke 4 constitutes a magnetic circuit by magnetic pole portions 4 a and 4 b arranged to face the outer peripheral curved surface with the permanent magnet 2. An electromagnetic coil 5 is configured by winding a conductive wire around a bobbin 5a having terminal pins.

  After one or more (2-N) stator yokes 4 are stacked and connected, the electromagnetic coil 5 is inserted into the stator yoke 4 from the direction of arrow A to the root. Thereafter, the electromagnetic coil 5 is inserted and positioned from the blade mounting side (upper side in FIG. 1) to the magnet base plate 1 side (lower side in FIG. 1). In this state, the rotating shaft 3b of the shutter blade 3 with the permanent magnet 2 integrated therein is fitted in the blade rotation bearing hole 1a of the magnet base plate 1, and the rotating shaft 3a rotates the blade of a blade pressing plate 6 described later. The bearing hole 6a is rotatably fitted. At this time, as described above, the magnetized portions (N, S) of the outer peripheral curved surface of the permanent magnet 2 are arranged to face the magnetic pole portions 4a, 4b.

  Reference numeral 6 denotes a blade pressing plate formed of a single plate having an opening 6 b through which a light beam passes, and is arranged so that an appropriate gap is formed between the magnet base plate 1 and the shutter blade 3. The blade presser plate 6 presses and fixes the flange portions 5b and 5c of the bobbin of the stator yoke 4 and the electromagnetic coil 5 when assembling. Further, the blade pressing plate 6 is formed with a traveling groove (hereinafter referred to as a traveling rail) 6e that allows the shutter blade 3 to freely rotate, and stoppers are provided at both ends of the operating area of the traveling rail 6e. Parts 6c and 6d are provided. The shutter blade 3 rotates in a state where an engagement portion 3c formed in a U shape at the tip end sandwiches the traveling rail 6e of the blade pressing plate 6.

  The electromagnetically driven shutter, which is an example of the light amount adjusting device configured as described above, is disposed within the circumference of the lens barrel together with the lens group 12.

  Here, the operation of the electromagnetically driven shutter having the above configuration will be described. When the energization of the electromagnetic coil 5 is off, the stator yoke 4 is in a non-excited state, and a force (detent torque) attracted between the magnetic pole portion of the outer peripheral surface of the permanent magnet 2 and the magnetized portions 4a and 4b. Thus, the shutter blade 3 is held at the blade stop position in FIG. That is, at this time, the shutter blade 3 is magnetically attracted by the permanent magnet 2 in the direction in which the shutter blade 3 abuts on the stopper portion 6c formed on the blade pressing plate 6 at the position shown in FIG.

  From the above state, it is assumed that the electromagnetic coil 5 is energized and controlled so that the magnetic pole portion 4a of the stator yoke 4 is the S pole and the magnetic pole portion 4b is the N pole. Then, an attractive force and a repulsive force are generated between the stator yoke 4 and the permanent magnet 2, and the permanent magnet 2 rotates at an angle of about 40 ° to 50 ° counterclockwise from the state of FIG. As a result, the shutter blade 3 rotates from the open state to the closed position that shields the opening 6b.

  Here, the arrangement relationship between the permanent magnet 2 and the stator yoke 4 is such that the detent torque becomes zero at an operating position of about 20 ° to 25 °, which is an intermediate point between all the operating angles of the permanent magnet 2 of 40 ° to 50 °. The direction of is also arranged to switch to the left and right. Therefore, it is assumed that after the energization of the electromagnetic coil 5 is performed and the permanent magnet 2 and the shutter blade 3 are rotated counterclockwise, the energization off state of the electromagnetic coil 5 is maintained. Even in such a case, the shutter blade 3 comes into contact with the stopper portion 6d formed at the operation end position of the blade pressing plate 6 by the detent torque, and FIG. 2 shows the opposite position (the position where the opening portion 6b is shielded). A stable stop will occur.

  When the electromagnetic coil 5 is energized and controlled so that the magnetic pole portion 4a of the stator yoke 4 has an N pole and the magnetic pole portion 4b has an S pole, a repulsive force is generated between the stator yoke 4 and the permanent magnet 2. An attractive force is generated, and the permanent magnet 2 rotates in the clockwise direction at an angle of about 40 ° to 50 °, so that the shutter blade 3 returns to the initial position (position where the opening 6b shown in FIG. 2 is opened).

  In this way, the shutter blade 3 is moved to the blade retainer plate 6 around the rotation shafts 3a and 3b under the action of two forces of magnetic attraction and repulsion by forward and reverse energization of the electromagnetic coil 5. It rotates to both ends within the range of the formed stopper portions 6c and 6d. At this time, the engaging portion 3 c of the shutter blade 3 is guided and rotated by the traveling rail 6 e of the blade pressing plate 6. After the energization of the electromagnetic coil 5 is turned off, the permanent magnet 2 is urged by the detent torque to the end of the stopper portion 6c of the blade pressing plate 6, and the state is maintained and stopped.

As described above, the drive control of the shutter blades is performed by the energization control of the positive and reverse currents to the electromagnetic coil 5. In the shutter blade drive control of a compact camera or the like, the shutter blade opening / closing drive control is performed at the current on / off energization time and timing of the electromagnetic coil 5.
According to the above Example 1, it has the following effects.

  In the conventional electromagnetically driven shutter described above, each of the two blades, the winding coil and the magnet are held in a space formed by a combination of different members. For this reason, the entire thickness is increased, and the thickness reduction is not sufficient. Further, since each blade is sandwiched between the blade pressing plate and the shutter base plate, the size reduction is not sufficient.

  On the other hand, in the electromagnetically driven shutter of the first embodiment, the shutter blade 3, the permanent magnet (magnet) 2, and the winding coil 5 are all sandwiched between the blade pressing plate 6 and the magnet base plate 1. Therefore, the thickness of the shutter base plate in the conventional example can be reduced, and the entire electromagnetically driven shutter can be reduced in size. In addition, since the electromagnetically driven shutter can be reduced in size as described above, it is advantageous in terms of power consumption.

  Furthermore, in the electromagnetically driven shutter according to the first embodiment, the engaging portion 3c is formed at the tip of the shutter blade 3, and the blade pressing plate 6 (specifically, the traveling rail 6e) is sandwiched between the engaging portion 3c. Therefore, it is not necessary to sandwich the blades from both sides by the blade pressing plate and the shutter base plate as in the prior art, and the electromagnetically driven shutter can be reduced in thickness and size accordingly.

  As is clear from the above, it is possible to reduce the size of the lens in the radial direction of an electromagnetically driven shutter used in a camera, particularly a digital still camera, particularly by reducing the size of the electromagnetically driven unit. That is, it is possible to reduce the size in the optical axis direction, that is, to reduce the thickness.

  FIG. 6 is a diagram showing only the main configuration of an electromagnetically driven shutter which is an example of a light amount adjusting device according to the second embodiment of the present invention. Other configurations are the same as those in FIG.

  Differences from the first embodiment will be described. In the first embodiment, the rotating shafts 3a and 3b of the shutter blade 3 are integrally formed with the shutter blade 3. The rotary shafts 3 a and 3 b are configured to be rotatably fitted and held by a blade rotation bearing hole 1 a formed in the magnet base plate 1 and a blade rotation bearing hole 6 a formed in the blade pressing plate 6.

  On the other hand, in Example 2 of this invention, the blade | wing rotation shaft 1d is provided in the position which the blade | wing rotation bearing hole 1a of the magnet base plate 1 had. A bearing hole 3d provided in the shutter blade 3 is fitted into the blade rotation shaft 1d.

  That is, in the second embodiment, the rotation shaft hole 3d integrally formed with the shutter blade 3 is rotatably fitted and held on the blade rotation shaft 1d provided on the magnet base plate 1, and the outer diameter of the rotation shaft hole 3d. The permanent magnet 2 is integrated into the part by insert molding, two-color molding, or press molding after separate molding.

  FIG. 7 is a diagram showing only the configuration of the main part of an electromagnetically driven shutter which is an example of a light quantity adjusting device according to Embodiment 3 of the present invention. Other configurations are the same as those in FIG.

  In FIG. 7, the permanent magnet 2 is a plastic magnet having good slidability, and a blade rotation bearing hole 2 a is provided in the permanent magnet 2. And this blade | wing rotation bearing hole 2a is set as the structure fitted and hold | maintained so that rotation to the blade | wing rotation shaft 1e provided in the magnet base plate 1 was possible. A shutter blade 3 is fixed to the upper part of the permanent magnet 2.

  According to the above first to third embodiments, the electromagnetically driven shutter can be arranged very thin, and the electromagnetically driven shutter can be reduced in thickness and size. Furthermore, it is possible to adopt a configuration in which components are assembled from one direction even when assembled, and an electromagnetically driven shutter with very good assemblability can be obtained. Furthermore, not only can the electromagnetically driven shutter thus reduced in size and thickness be driven at high speed, but also an electromagnetically driven shutter that achieves both small size and low power consumption without increasing power consumption. Is something that can be done.

  In the first to third embodiments, the electromagnetically driven shutter including the shutter blade 3 has been described as an example of the light amount adjusting device. However, the present invention is not limited to this. For example, an electromagnetically driven diaphragm that uses aperture blades instead of shutter blades and changes the aperture by inserting and removing the aperture blades into the opening may be used. Furthermore, the light quantity adjusting device provided with both the shutter blade and the aperture blade may be used. Further, it may be a light amount adjusting device provided with a transmitted light beam adjusting blade such as an ND filter for adjusting the amount of light beam passing through the aperture.

It is a disassembled perspective view which shows the electromagnetically driven shutter concerning Example 1 of this invention. It is a top view which shows the electromagnetically driven shutter of Example 1 of this invention. It is sectional drawing which shows the electromagnetically driven shutter of Example 1 of this invention. FIG. 4 is a cross-sectional view illustrating a state where the electromagnetically driven shutter according to the first exemplary embodiment of the present invention is cut at a portion different from FIG. 3. It is a schematic block diagram which shows the camera provided with the electromagnetically driven shutter of Example 1 of this invention. It is sectional drawing which shows only the principal part structure of the electromagnetically driven shutter concerning Example 2 of this invention. It is sectional drawing which shows only the principal part structure of the electromagnetically driven shutter concerning Example 3 of this invention.

Explanation of symbols

Reference Signs List 1 magnet base plate 1d blade rotation shaft 1e blade rotation shaft 2 permanent magnet 3 shutter blades 3a, 3b rotation shaft 3c engagement portion 3d rotation shaft hole 4 stator yoke 5 electromagnetic coil 6 blade presser plate 6a blade rotation bearing hole 6b open aperture 6c , 6d Stopper part 6e Traveling rail

Claims (4)

A shielding member for shielding incident light;
A pressing member that covers the shielding member;
A base plate that rotatably holds the shielding member together with the pressing member;
Driving means for driving the shielding member;
In the light quantity adjusting device having
The pressing member has a traveling rail portion that guides the rotation of the shielding member at an end portion, and an engaging portion formed so as to sandwich the traveling rail portion at the tip of the shielding member. The light quantity adjusting device, wherein the shielding member and the driving means are arranged between the base plate and the pressing member. The pressing member, the light amount adjusting device according to claim 1, characterized in that it comprises a stopper portion for rotating regulation of the shielding member provided at both ends of the travel rail section. The shielding member, the light amount adjusting device according to claim 1 or 2, characterized in that the shutter blades, a diaphragm blades or transmitted light beam regulating blade. A camera comprising the light amount adjusting device according to any one of claims 1 to 3 .

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