JP2006174629A - Electromagnetic driving unit, light intensity controller, and optical instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic driving unit which reconciles downsizing and energy-saving. <P>SOLUTION: This electromagnetic driving unit has a permanent magnet 3 which is attached integrally to a position apart in its radial direction from the center to a rotatable driven member 2, stators 5 and 6 which are arranged to face the side of one magnetizing part (N pole) of a permanent magnet, and an electromagnetic coil 7 which energizes the stator yoke. This makes the magnetic attraction and repulsion arising between one magnetizing part of the permanent magnet and the stator yoke work on the above permanent magnet thereby rotating the driven member where the permanent magnet is integrated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electromagnetic drive device that drives a driven member, a light amount adjustment device that includes the electromagnetic drive device, and an optical apparatus such as a digital camera that includes the light amount adjustment device.

  Conventionally, an outer peripheral surface of a rotor magnet made of a permanent magnet is magnetized to two poles (N pole and S pole), and a rotating shaft formed integrally with a drive shaft of a driven member is attracted by a magnetomotive force generated by an exciting coil. An electromagnetic drive device that rotates by repulsion is known. In addition, this type of electromagnetic drive device is provided as a drive source, and the amount of light used in an optical device such as a digital camera that opens and closes, for example, a lens shutter blade, using the rotation of the rotation shaft of the electromagnetic drive device. An apparatus has also been proposed (Patent Document 1).

  In recent video camera and still camera products that require the above light control devices, there is a strong need to reduce the size, thickness, and power consumption. Therefore, the light control devices are inevitably small, thin, and low power consumption. There is a demand for electric power.

In particular, there are two demands for downsizing, and one is that the distance from the light quantity adjusting member such as the shutter blade and the diaphragm to the image pickup device such as the CCD and the distance to the drive source for autofocus and zoom are reduced. This is to reduce the dimension (height) in the optical axis direction of the light quantity adjusting device. The other is that the lens barrel that holds the optical member basically has a circular cross section centered on the optical axis, and the light amount adjusting device, autofocus, zoom, and other mechanisms are located in the gap between the optical lens group. Therefore, these members are intended to be contained in a cylinder as small as possible with the optical axis as the center.
Japanese Patent Laid-Open No. 9-211531

  However, the electromagnetic drive device provided in the above conventional light quantity adjusting device that rotates by repulsion with the magnetomotive force generated at the outer periphery of the rotor magnet made of a permanent magnet has insufficient torque, and is reduced in size and consumption. It had the problem that it was difficult to use electric power. This is because the volume of the rotor magnet made of a permanent magnet (area facing the stator yoke) = the generated torque, and considering the necessary torque, there has been a limit to downsizing. As a result, it has been difficult to achieve both downsizing and low power consumption (since this type of small electromagnetic drive device requires a large amount of power consumption to obtain high torque).

(Object of invention)
An object of the present invention is to provide an electromagnetic drive device, a light amount adjusting device, and an optical apparatus that achieve both miniaturization and low power consumption.

  In order to achieve the above object, a first aspect of the present invention provides a permanent magnet integrally attached to a rotatable driven member at a position radially away from the center of rotation thereof, A magnetic force generated between the one magnetized portion of the permanent magnet and the stator yoke, the stator yoke being disposed so as to face one of the magnetized portions; and an electromagnetic coil for exciting the stator yoke. Thus, an electromagnetic drive device that causes a permanent attraction force and a repulsive force to act on the permanent magnet and rotates the driven member integrated with the permanent magnet is provided.

In order to achieve the above object, the invention according to claim 3 is the electromagnetic drive device according to claim 1, the base having an opening through which light passes, and the permanent magnet of the electromagnetic drive device. And a light amount adjusting member that is a driven member, and the amount of light passing through the opening is adjusted by rotating the light amount adjusting member by the electromagnetic driving device and opening and closing the opening. This is a light quantity adjusting device.

  Similarly, in order to achieve the above object, the invention according to claim 4 includes a plurality of electromagnetic driving devices according to claim 1, a base having an opening that defines a maximum amount of light passing through, and a plurality of the plurality of electromagnetic driving devices. A plurality of light intensity adjusting members, each of which is a driven member having a hole having a different diameter, and each of the permanent magnets of each of the electromagnetic driving devices is integrally attached; The light amount adjusting member of the electromagnetic driving device is rotated by a driving device, and a hole portion of the light amount adjusting member is caused to enter the opening to adjust a light amount passing through the opening.

  Similarly, in order to achieve the above object, the invention described in claim 5 is an optical apparatus including the light amount adjusting device described in claim 3 or 4.

  According to the present invention, it is possible to provide an electromagnetic drive device, a light amount adjusting device, or an optical apparatus that achieves both miniaturization and low power consumption.

  The best mode for carrying out the present invention is as shown in Examples 1 and 2 described below.

  FIGS. 1 to 4 are diagrams related to the first embodiment of the present invention. Specifically, FIG. 1 is an exploded perspective view showing a configuration of a light amount adjusting device provided with an electromagnetic drive device, and FIG. 2 is a light amount shown in FIG. FIG. 3 is a cross-sectional view of the light amount adjusting device shown in FIG. 1. 4 is a cross-sectional view showing details of the arrangement of the stator yoke and the permanent magnet of the electromagnetic drive device shown in FIG.

  This light quantity adjusting device is configured as a shutter device used in an optical apparatus such as a digital camera or a compact camera.

  In FIG. 1 to FIG. 4, reference numeral 1 denotes a shutter base plate which is a base material that defines the maximum aperture diameter of the passing light beam. The opening 1 d opened and closed by a shutter blade 2 described later and the operating range of the shutter blade 2 are defined. It has the stopper parts 1b and 1c to regulate. Reference numeral 2 denotes a shutter blade that is a driven member configured to be able to rotate (arc movement: pendulum movement) by fitting a rotation bearing hole 2a to a rotation shaft 1a provided on the shutter base plate 1, and the stopper portion 1b. And 1c, the opening 1d of the shutter base plate 1 is opened and closed to adjust the amount of light passing through the opening 1d.

  3 is a permanent magnet composed of a neodymium-based (Nd-Fe-B) or samarium-based compression magnet, bond magnet, plastic magnet, or the like. As shown in FIG. N pole and S pole) are magnetized (magnetized). The permanent magnet 3 is attached to the shutter blade 2 by being attached to the shutter blade 2 at a predetermined distance in the radial direction from the rotation axis center (position of the mounting hole 2b) by adhesion or the like (or a driven member). It is also possible to affix and fix to the upper surface of the shutter blade 2). Reference numeral 4 denotes a blade case, which secures a travel space of the shutter blade 2 and is attached to the shutter base plate 1 to enable arc movement of the shutter blade 2 within a predetermined range.

  An R (right side) stator yoke 5 made of a soft magnetic material is fixed to the shutter base plate 1. An L (left side) stator yoke 6 made of a soft magnetic material is also fixed to the shutter base plate 1 so as to face the stator yoke 5 with a predetermined gap. The stator yokes 5 and 6 have the shortest magnetic field direction (indicated by the broken lines in FIG. 4) generated when the magnetic pole portions 5a and 6a of the stator yokes 5 and 6 are excited with respect to the magnetization direction (thickness direction) of the permanent magnet 3. In the direction perpendicular to the direction shown). At this time, one magnetized surface (N pole surface) of the stator yokes 5 and 6 and the permanent magnet 3 is at a position having a gap of 0.3 mm or more, for example.

  In other words, the permanent magnet 3 has a direction in which the magnetization direction magnetized in two poles in the thickness direction and the shortest magnetic field direction generated in the excited state from the magnetic pole portions 5a and 6a of the stator yokes 5 and 6 are orthogonal to each other. In addition, the shutter blade 2 is disposed outside the range of the shortest magnetic field direction having a predetermined distance in the radial direction from the rotation axis center. Further, when the stator yokes 5 and 6 are excited, the permanent magnet 3 floats and rotates in a direction that differs by at least 5 ° or more with respect to the direction of the shortest magnetic field generated between the magnetic pole portions 5a and 6a (see FIG. 4). Offset placement. Thereby, the influence of the magnetic reaction with respect to the other magnetized surface (S pole surface) of the permanent magnet 3 and the magnetic pole portions 5a and 6a of the stator yokes 5 and 6 is reduced. Therefore, as shown in FIG. 4, the permanent magnet 3 has a magnetic field generated between the magnetic pole portions 5a and 6a when the stator yokes 5 and 6 are excited and is magnetized to different poles (N pole and S pole). Since the permanent magnet 3 is integrally formed with the shutter blade 2, it is arranged between the magnetic pole portions 5 a and 6 a. The generated magnetic field directly acts on the shutter blade 2. This is because, as in the conventional type, the rotor magnet is rotated by attraction and repulsion with the magnetomotive force generated at the outer periphery of the rotor magnet (both N and S poles) made of a permanent magnet, and the rotor magnet output shaft This is different from an electromagnetic drive device that applies circular motion to a driven member such as a shutter blade. In other words, the electromagnetic drive device is small and achieves low power consumption.

  Reference numeral 7 denotes an electromagnetic coil made of a copper wire and a mold bobbin, and stator yokes 5 and 6 are connected and joined in the bobbin of the electromagnetic coil 7 to constitute a magnetic circuit.

  The electromagnetic drive device according to the first embodiment includes the permanent magnet 3, the stator yokes 5, 6 and the electromagnetic coil 7. The shutter device which is an example of the light amount adjustment device includes the electromagnetic drive device, the shutter base plate 1, and the like. The shutter blade 2 and the blade case 4 are configured. The shutter device is disposed in the circumferential wall of a lens barrel such as a digital camera or in combination with a lens unit.

  Next, the operation of the electromagnetic drive device and the shutter device configured as described above will be described below.

  In the off state in which the electromagnetic coil 7 is not energized, the stator yokes 5 and 6 are in a non-excited state. At this time, the permanent magnet 3 magnetized in two poles (N pole, S pole) in the thickness direction and one of the stator yokes 6 among the stator yokes 5 and 6 arranged in the direction perpendicular to the magnetization direction. The magnetic pole portion 6a is held in the state shown in FIGS. 2 to 4 by the attractive force (detent force). That is, since the permanent magnet 3 is integrated with the rotatable shutter blade 2 as described above, the permanent magnet 3 is attracted to the magnetic pole part 6a side of the stator yoke 6 by the attractive force (detent force), and the shutter blade Reference numeral 2 denotes a stable stop at a position in contact with the stopper 1 c of the shutter base plate 1. This state is the initial position of the shutter blade 2.

  As shown in FIG. 4, when energization control is performed on the electromagnetic coil 7 so that the magnetic pole portion 6 a of the stator yoke 6 is an N pole and the magnetic pole portion 5 a of the stator yoke 5 is an S pole, A repulsive force is generated between the N pole of the magnetic pole portion 6a and the N pole of the permanent magnet 3, and an attractive force is generated between the S pole of the magnetic pole portion 5a of the stator yoke 5 and the N pole of the permanent magnet 3. The permanent magnet 3, that is, the shutter blade 2, moves in the clockwise direction (arrow direction) from the state of FIG. 4 in an angle range of about 40 ° to 50 ° (range restricted by the stopper portions 1 c and 1 b). The arc moves to a position where it abuts, more specifically, the levitating rotation, and after the levitating rotation, the permanent magnet 3 and the magnetic pole portion 5a of the stator yoke 5 are brought into close contact with the opening 1d of the shutter base plate 1 by the attractive force generated by excitation. Stopped and held. As a result, the shutter blade 2 changes the opening 1d from the open state to the light-shielded state.

  Thereafter, when the energization of the electromagnetic coil 7 is turned off, the shutter blade 2 is moved to the stopper 1b of the shutter base plate 1 by the attractive force (detent force) between the permanent magnet 3 and the magnetic pole portion 5a of the stator yoke 5 this time. It abuts and is held in a stable stop state at this position.

  Next, conversely to FIG. 4, when energization control is performed on the electromagnetic coil 7 so that the magnetic pole portion 6 a of the stator yoke 6 is an S pole and the magnetic pole portion 5 a of the stator yoke 5 is an N pole, the stator coil 6 is energized. A repulsive force is generated between the magnetic pole portion 5 a of the yoke 5 and the permanent magnet 3, and an attractive force is generated between the magnetic pole portion 6 a of the stator yoke 6 and the permanent magnet 3, so that the permanent magnet 3, that is, the shutter blade 2. However, in the counterclockwise angle range of about 40 ° to 50 °, it floats and rotates to the initial position where it abuts against one stopper portion 1c, and after the floating rotation, the permanent magnet 3 and the magnetic pole portion 6a of the stator yoke 6 generate. It is stopped and held away from the opening 1d of the shutter base plate 1 by the suction force acting on. Accordingly, the opening 1d is returned from the state where the opening 1d is shielded by the shutter blade 2 to the initial state where it is opened.

  According to the first embodiment, the stator yokes 5 and 6 are energized with the stator yokes 5 and 6 fixed to the shutter base plate 1 so that the magnetic pole part 5a and the magnetic pole part 6a face each other with a gap. The magnetic pole portions 5a and 6a are integrally attached to an electromagnetic coil 7 for exciting different poles and a shutter blade 2 that rotates about a rotation axis with a predetermined distance in the radial direction from the rotation axis center, and a stator. Permanently arranged so that the magnetic field generated between the magnetic pole portions 5a and 6a of the yokes 5 and 6 acts only on one of the magnetized surfaces (N pole surface in FIG. 4) magnetized on different poles. An electromagnetic drive device is constituted by the magnet 3, and a magnetic attractive force and a repulsive force generated between the permanent magnet 3 and the stator yokes 5, 6 are applied only to one magnetized surface of the permanent magnet 3, The permanent magnet There has been so as to arc motion between the holding or these positions the shutter blades 2, which is integrated in a predetermined position (initial and open the opening 1d position or position shielding the opening 1d).

  Specifically, the shutter blade 2 integrated with the permanent magnet 3 is predetermined by the attractive force generated between the stator yokes 5 and 6 and one magnetized surface of the permanent magnet 3 when the stator yokes 5 and 6 are not excited. When the stator yokes 5 and 6 are excited, the repulsive force and the attractive force generated between the magnetic pole portions 5a and 6a of the stator yokes 5 and 6 and one magnetized surface of the permanent magnet 3 are opened. An arc is moved from the initial position where the portion 1d is opened to a position where the opening 1d is shielded, or from the position where the opening 1d is shielded to the initial position where the opening 1d is opened.

  As a result, it is possible to realize a reduction in size (thinning) and reduction in power consumption as compared with a conventional electromagnetic drive device in which the volume of the rotor magnet made of a permanent magnet (area facing the stator yoke) = generated torque.

  In addition, a shutter device (light amount adjusting device) using the electromagnetic driving device having the above configuration as a driving source of the shutter blade 2 which is an example of a driven member, and further an optical device such as a digital camera equipped with the shutter device. Thus, the dimension (height) of the shutter device in the optical axis direction can be reduced, and the shutter device can be housed in a cylinder such as a lens barrel that is as small as possible with the shutter device as the center of the optical axis. This makes it possible to reduce the size and power consumption of devices and digital cameras.

  Next, a light amount adjusting apparatus according to Embodiment 2 of the present invention will be described. In the first embodiment, the permanent magnet 3 disposed integrally with the shutter blade 2 is magnetized by being magnetized with two poles (N pole, S pole) in the thickness direction, but the second embodiment of the present invention. As shown in FIG. 5, the permanent magnet 30 is disposed at a predetermined distance in the radial direction from the rotation bearing hole 2a of the shutter blade 2 and is magnetized to two poles (N pole, S pole) in the radial direction. Yes. Therefore, the permanent magnet 30 does not float and only moves in a circular arc around the rotating shaft 1a. Other structures are the same as those of the first embodiment.

  In the electromagnetic drive device having the above configuration, when energization control is performed on the electromagnetic coil 7 (energization is turned on / off), a magnetic field generated between the magnetic pole portions 5a and 6a of the stator yokes 5 and 6 is generated by the permanent magnet 30. Acting in the radial direction as a force to repel and attract one of the magnetized surfaces, the permanent magnet 30, that is, the shutter blade 2, shields the opening 1d from the initial position where the opening 1d (not shown) is opened. The arc movement is performed to the position or from the position where the opening 1d is shielded to the initial position where the opening 1d is opened.

  That is, the permanent magnet 30 in the second embodiment is integrally attached to the shutter blade 2 with a predetermined distance from the rotation center of the shutter blade 2, which is a driven member capable of arc motion, as in the first embodiment. When the stator yokes 5 and 6 are excited, the magnetic field generated between the magnetic pole portions 5a and 6a is applied only to one of the magnetized portions (N pole in FIG. 5) magnetized to the S and N poles. It will be arranged to act.

  Thereby, it is possible to obtain the same effect as in the first embodiment.

  In each of the above embodiments, the shutter blade 2 is assumed as a driven member. However, the shutter blade 2 is not limited to this, and is a diaphragm blade or a neutral density filter (ND (Neutral Density Filter) filter). Also good.

  When the driven member is an aperture blade, the configuration of the light amount adjusting device includes a plurality of small (thin) electromagnetic drive devices set on the shutter base plate 1 and a plurality of aperture blades having holes of different diameters. And an arbitrary electromagnetic driving device is driven with respect to the opening 1d to allow the corresponding diaphragm blade to enter the opening 1d to obtain a desired amount of light. In other words, a two-stage or more diaphragm switching mechanism is provided. It is conceivable to use a device.

  In each of the above-described embodiments, for example, the opening / closing drive control of the shutter blades, the diaphragm, etc. of the digital camera is assumed, and the opening / closing drive control is performed by the forward / backward current control to the electromagnetic coil 7. For example, when the present invention is applied to opening / closing drive control of a diaphragm / shutter of a compact camera, the opening / closing drive control of the diaphragm / shutter is performed in accordance with the energization time and timing when the current supplied to the electromagnetic coil 7 is turned on / off.

It is a disassembled perspective view which shows the structure of the light quantity adjustment apparatus which comprised the electromagnetic drive device concerning Example 1 of this invention. It is a top view of the light quantity adjustment apparatus shown in FIG. It is sectional drawing of the light quantity adjustment apparatus shown in FIG. It is sectional drawing which shows the detail of arrangement | positioning of the stator yoke of the electromagnetic drive device shown in FIG. 1, and a permanent magnet. It is a top view which shows a part of structure of the light quantity adjustment apparatus provided with the electromagnetic drive device concerning Example 2 of this invention.

Explanation of symbols

1 Shutter base plate (base)
1a Blade shaft 1b, 1c Stopper portion 1d Opening portion 2 Shutter blade (driven member, light amount adjusting member)
2a Rotating bearing hole 3,30 Permanent magnet 4 Blade cover 5 Stator yoke 6 Stator yoke 7 Electromagnetic coil

Claims (5)

A permanent magnet integrally attached to a rotatable driven member at a position radially away from the center of rotation;
A stator yoke disposed to face one of the magnetized portions of the permanent magnet;
An electromagnetic coil for exciting the stator yoke;
Have
A magnetic attraction force and a repulsive force generated between one magnetized portion of the permanent magnet and the stator yoke are applied to the permanent magnet, and the driven member integrated with the permanent magnet is rotated. An electromagnetic drive device. When the stator yoke is not excited, the driven member is held in one or the other position by an attractive force generated between the stator yoke and one magnetized portion of the permanent magnet,
During excitation of the stator yoke, a repulsive force generated between the stator yoke and one magnetized portion of the permanent magnet acts on the permanent magnet, and the driven member moves from the one to the other position, or the The electromagnetic drive device according to claim 1, wherein the electromagnetic drive device rotates from the other to one position. The electromagnetic drive device according to claim 1 or 2,
A base having an opening through which light passes;
A light quantity adjusting member, which is a driven member, to which the permanent magnet of the electromagnetic driving device is integrally attached;
Have
A light amount adjusting device that adjusts the amount of light passing through the opening by rotating the light amount adjusting member by the electromagnetic driving device and opening and closing the opening. A plurality of electromagnetic drive devices according to claim 1 or 2,
A base having an opening that defines the maximum amount of light passing through;
A plurality of light quantity adjusting members, which are driven members, each having a permanent magnet attached to each of the plurality of electromagnetic driving devices, each having a hole having a different diameter;
Have
The light amount adjusting member of the electromagnetic driving device is rotated by an arbitrary electromagnetic driving device of the plurality of electromagnetic driving devices, and a hole of the light amount adjusting member is caused to enter the opening to reduce the amount of light passing through the opening. A light amount adjusting device characterized by adjusting. An optical apparatus comprising the light amount adjusting device according to claim 3.

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