JP2001356387A - Electromagnetic driving device, electromagnetically driven light quantity controller and optical device incorporating the same electromagnetic driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic driving device capable of suppressing the start-up delay and a bound at switching the opening/closing direction of a light quantity control member and capable of smoothly and rapidly transmitting a motive power necessary for opening/closing the light quantity control member, and to provide an electromagnetically driven light quantity controller and optical equipment capable of attaining the increase of the speed of opening/ closing the light quantity controlling member and power-saving by using the electromagnetic driving device. SOLUTION: The device is provided with a magnet driving body 107 having both of N and S magnetic surfaces, a core 103 having attracting surfaces 116 and 117 respectively facing both magnetic surfaces of the magnetic driving body 107 and for forming a magnetic circuit, and a coil 105 for magnetizing the core 103 and also switching the magnetic polarity in accordance with the flowing direction of the current, and an attracting force reducing means is arranged between the magnetic surfaces of the magnet driving body 107 and the attracting surfaces 116 and 117 of the core.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic driving device for quickly and power-saving switching of power to be applied to a light amount adjusting member, and an electromagnetic driving light amount for incorporating the electromagnetic driving device to open and close the light amount adjusting member. The present invention relates to an adjusting device and an optical device.

[0002]

2. Description of the Related Art Conventionally, a rotor and a stator are provided as a driving device for opening and closing a light amount adjusting member.
A structure in which both are electromagnetically switched to perform a rotation or swing operation is often used. The rotor is constituted by a swingably mounted magnet, and the stator is constituted by an electromagnet formed by winding a coil around a core such as an iron core. FIG. 11 shows the structure of an electromagnetic drive device configured by combining an aperture drive mechanism 40 that performs aperture adjustment using a servomotor and a filter drive mechanism 29 that opens and closes a filter for attenuating the amount of light ( JP-A-49-12
9529).

The filter drive mechanism 29 includes an O-shaped iron core 30 concentrically arranged on the outer periphery of a rear mount screw 2 for mounting a rear lens group, a coil 31 wound around the O-shaped iron core 30, and a light-attenuating light at one end. And a support arm 13 having a movable permanent magnet 15 disposed at the other end.

[0004] The O-shaped iron core 30 is shown in FIG.
As shown in (b), both ends are opposed to each other,
A magnetic pole is formed at each end in a forked shape, and a movable permanent magnet 15 is rotatably arranged between the magnetic poles. A circular light attenuating filter 12 is attached to the movable permanent magnet 15 via a support arm 13. (A) shows a state where the movable permanent magnet 15 stops at a position where the exposure hole 11 at the center of the O-shaped iron core 30 is closed.
2B, the current flowing in the coil 31 is caused to flow in the opposite direction to that of FIG. 2A, so that the bifurcated magnetic pole polarity of the O-shaped iron core 30 is reversed, and the movable permanent magnet 15 is rotated in accordance with the bifurcated magnetic pole. This shows the state in which it has moved. At this time, the filter 12 stops at a position where the filter 12 is separated from the exposure hole 11 as shown in FIG. Thus, by alternately switching the current direction of the coil 31,
The opening and closing operation of the filter 12 attached to the support arm 13 is performed.

[0005]

The above-mentioned FIG.
In the filter driving mechanism 29 shown in FIG.
When the magnetic pole of the movable permanent magnet 15 is attracted to or pulled away from the magnetic pole surface where the excitation direction of 0 is switched and the polarity is alternately reversed, the support arm 13 and the filter 12 connected to the movable permanent magnet 15 are pulled. Is rotated. However, when the filter 12 is completely open or completely closed, the magnetic force is strongly acting between the magnetic pole of the iron core 30 and the magnetic pole of the movable permanent magnet 15, so that the filter 12 rotates in the opposite direction from this state. A large driving force is required to move it. Then, in order to obtain a large driving force, the current flowing through the coil 31 must be increased to increase the exciting force, which consumes power accordingly. In addition, in the above-described conventional structure, when the excitation direction of the coil 31 is switched, if the magnetic holding force between the magnetic pole of the iron core 30 and the movable permanent magnet 15 is too strong, the start of the separating filter 12 is delayed, or the filter 12 is completely stopped. There were also problems such as bounces occurring before.

Accordingly, the present invention provides an electromagnetic drive device which can suppress a start delay and a bounce when switching the opening / closing direction of a light amount adjusting member, and which can smoothly and quickly transmit power required for opening / closing, and this electromagnetic drive device. An object of the present invention is to provide an electromagnetically driven light amount adjusting device and an optical device which realize an improvement in opening / closing speed of a light amount adjusting member and power saving.

[0007]

According to a first aspect of the present invention, there is provided an electromagnetic driving apparatus comprising: an N-pole;
A magnet driving body having both magnetic surfaces of a pole, a stator forming a magnetic circuit having an attraction surface facing each of the two magnetic surfaces of the magnet driving body, and magnetizing the stator and magnetic polarity depending on the direction of current flow. And an attraction force reducing means is provided between the magnetic surface of the magnet driver and the attraction surface of the stator.

According to the present invention, the magnetic pole surface switched by the excitation direction of the coil wound on the stator and the magnetic pole surface of the magnet driving body are held with a minimum magnetic attraction force. The power consumption for maintaining is low. Further, since the switching of the magnetic holding surface between the magnet driver and the stator can be performed smoothly, the opening / closing speed of the light amount adjusting member interlocked with the switching can be improved, and the bounce at the time of stopping the opening / closing can be prevented.

According to a second aspect of the present invention, in the electromagnetic driving device according to the first aspect, the attraction force reducing means has an uneven surface provided on one of a magnetic surface of the magnet driving body and an attraction surface of the stator. It is characterized by being a rough surface portion.

According to the present invention, by forming one of the magnetic surface of the magnet driving body and the attraction surface of the stator into an uneven shape, a slight gap is formed in the joint surface between the magnet driving body and the stator. . The presence of this gap moderately weakens the magnetic coercive force between the two magnetic pole faces, and smoothly starts the magnet driver when the magnetization polarity of the stator is reversed. As a result, the opening / closing speed of the light amount adjusting member interlocked with the magnet driver is improved, and the opening / closing speed is increased.

According to a third aspect of the present invention, in the electromagnetic driving device according to the first aspect, the attraction force reducing means is a sheet-shaped member provided on one of a magnetic surface of a magnet driving body and an attraction surface of a stator. It is a non-magnetic member.

According to the present invention, the gap between the magnetic surface of the magnet driver and the attracting surface of the stator can be obtained simply by attaching a non-magnetic tape to one of the magnetic surface of the magnet driver and the attracting surface of the stator. Can be weakened moderately. For this reason, it is possible to easily limit the magnetic coercive force with small processing cost and material cost. Further, the magnetic coercive force can be adjusted according to the thickness of the tape and the number of tapes to be attached.

According to a fourth aspect of the present invention, in the electromagnetic driving device according to the first aspect, the attraction force reducing means is provided when the magnetic surface maintains a direction facing the attraction surface of the stator by rotation of the magnet driving body. It is characterized by comprising a gap portion and a stopper for preventing rotation of the magnet driving body for holding the gap portion.

According to the present invention, since the two magnetic poles are in a non-contact state in which a certain gap is maintained, there is little wear due to friction at a joint portion between the magnet driving body and the stator, and the noise is excellent and smooth. A switching operation can be performed.

According to a fifth aspect of the present invention, there is provided an electromagnetically driven light amount adjusting device having a magnet driving body having both magnetic surfaces of an N pole and an S pole, and an attracting surface opposed to both magnetic surfaces of the magnet driving body. And a stator that forms a magnetic circuit, and a light quantity adjusting device that is driven to open and close using an electromagnetic drive device that includes a coil that magnetizes the stator and switches the magnetic polarity according to the direction of current flow, wherein the electromagnetic drive device includes: An attraction force reducing means for reducing the attraction force between the magnetic surface of the magnet driving body and the attraction surface of the stator is provided.

According to the present invention, since the magnetic holding force can be appropriately adjusted by the magnet driving body and the stator having the above configuration, the opening / closing operation of the light amount adjusting member that swings in conjunction with the magnet driving body. But smoother and faster. Therefore, the opening / closing speed of the light amount adjusting member is increased and the power consumption is reduced as compared with the conventional electromagnetically driven light amount adjusting device.

An optical apparatus using the electromagnetically driven light amount adjusting device according to claim 6 of the present invention comprises: a magnet driver having both magnetic surfaces of an N pole and an S pole; A light quantity adjusting device that is driven to open and close by using an electromagnetic drive device that includes a stator having a suction surface to form a magnetic circuit, and a coil that magnetizes the stator and switches magnetic polarity according to the direction of current flow; In an optical apparatus including an optical lens system that constitutes an electromagnetic drive light amount adjustment device by incorporating a light amount adjustment device, the electromagnetic drive device is configured to reduce an attraction force between a magnetic surface of the magnet driving body and an adsorption surface of a stator. It is characterized in that a suction force reducing means for reducing is provided.

According to the present invention, manufacturing cost is reduced, shutter speed is improved, and power consumption is reduced by mounting the apparatus on an optical device such as a digital camera constructed by combining an optical lens with the electromagnetically driven light amount adjusting device having the above configuration. It is possible to produce a product that achieves a reduction in production.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electromagnetic drive device, an electromagnetic drive light amount adjusting device, and an optical apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view when the electromagnetic driving device of the present invention is incorporated in an electromagnetic driving light amount adjusting device (shutter device), and FIG. 2 is an exploded perspective view of the shutter device. FIG. 3 is a partially enlarged plan view of the shutter device, and FIG. 4 is an operation diagram for explaining the operation of the shutter device. FIG. 5 is a partially enlarged plan view of the first embodiment showing the suction force reducing means in the shutter device, and FIG. 6 is a partially enlarged plan view of the second embodiment of the suction force reducing means. FIG. 7 is a partially enlarged plan view of a third embodiment of the attraction force reducing means. FIG. 8 is a plan view of the shutter device in a state where the shutter blades are closed,
FIG. 9 is a plan view of the shutter device with the shutter blades opened, and FIG. 10 is a conceptual diagram in which the shutter device is incorporated in an optical device (camera body).

As described above, FIGS. 1 and 2 show the structure of the shutter device 100 incorporating the electromagnetic driving device 101. FIG. The shutter device 100 is mounted in a lens barrel of an optical device such as a camera, and includes a shutter mechanism 102 in addition to the electromagnetic driving device 101.

The electromagnetic driving device 101 includes a U-shaped core 103 made of a magnetic material such as iron, a coil 105 wound around the core 103, and a magnet driving member which is interposed between the core 103 and swings. 107.

As shown in FIG. 1, the core 103 is disposed on a disk-shaped base plate 109. For this reason, the shape of the core 103 is U-shaped along the outer peripheral surface of the base plate 109,
The arms 104 and 106 at both ends of the U-shape are elongated and curved. The arm 104,
A part of the facing surface of the magnet 106 includes a magnet driving body 10.
The suction surfaces 116 and 117 for sucking the magnetic surface 7 are formed. The suction faces 116 and 117 are
By switching the direction of the current flowing through the exciting coil 105 wound around the coils 4 and 106, the magnetization is alternately performed to the S pole or the N pole.

As shown in FIG. 3, the magnet driver 107 sandwiched between the attraction surfaces 116 and 117 of the core 103 has a slender octagonal shape, and the vicinity of a shaft 114 serving as a rotation axis is provided. The magnetization is divided into an S pole and an N pole in the longitudinal direction at the boundary. Also, this magnet driving body 10
The shaft 11 is attracted to or pulled away from the attraction surfaces 116 and 117 where the magnetic poles are reversed, depending on the direction of the current flowing through the coil 105 as described above.
Oscillation is repeated around the center 4 in a range sandwiched between the suction surfaces 116 and 117.

The swing operation of the magnet driver 107 will be described with reference to FIG. (A) sets the current flowing through the core 103 in the direction indicated by the arrow A, and
Then, the attracting surface 117 is magnetized to S, whereby the S pole surface of the magnet driver 107 is attracted to the attracting surface 116 and the N pole surface is attracted to the attracting surface 117 and stopped. is there. (B) is a diagram in which the current flowing through the core 103 is switched in the direction of arrow B, which is opposite to the above (a). The suction surface 116 is switched from N to S, the suction surface 117 is switched from S to N, and the magnet is magnetized. This shows a state where the magnetic surface of the driver 107 swings in the opposite direction to the above.
Further, (c) shows a state in which the swing in (b) is stopped, and the magnet driver 107 is fixed in a direction completely opposite to that of (a).

FIGS. 5 to 7 show a core 10 having the above-described structure.
3 is provided with suction force reducing means. FIG. 5 shows a first embodiment of the attraction force reducing means. The attraction surface 116 of the core 103 with which the magnetic pole of the magnet driver 107 is in contact.
117 is formed on one or both of the attraction surfaces as a rough surface 118 having an uneven shape. 5 to 7 show an example in which the suction force reducing means is provided at or near the suction surface 116. FIG. In this embodiment, the rough surface 118 is formed by a plurality of streaks engraved on the suction surface 116. However, the shape of the rough surface 118 and the depth of the unevenness are not particularly limited. When the magnetic surface of the core 1 contacts the magnetic surface of the magnet driver 107,
It is sufficient that the attraction force between the attraction surface 03 and the attraction surface 116 is small. Further, the present invention is not limited to the case where the rough surfaces 118 are formed on the attraction surfaces 116 and 117 of the core 103, and the magnet driver 1
A similar effect can be expected even if a similar uneven surface is provided on the magnetic surface 07.

FIG. 6 shows a second embodiment of the suction force reducing means. In this embodiment, the magnet driver 10
The sheet-shaped non-magnetic member 119 is attached to the attracting surface 116 of the core 103 with which the magnetic pole 7 contacts. The non-magnetic member 119 is, for example, an adhesive tape made of vinyl or cloth, and the material of the tape and the number of tapes to be applied are appropriately selected and used depending on how much the magnetic coercive force is reduced. The tape may be attached over the entire surface of the magnet driver 107 that contacts the magnetic surface, or may be attached in a grid or stripe pattern at a certain interval. The same effect can be expected even when a similar non-magnetic member 119 is attached to the magnetic surface of the magnet driver 107.

FIG. 7 shows a third embodiment of the suction force reducing means. Here, the configuration is such that the magnetic pole surface of the magnet driver 107 and the attraction surface 116 of the core 103 are stopped at a predetermined position in a non-contact state. In order to realize this state, a stopper 120 for preventing the swing of the magnet driver 107 is provided near any one of the suction surfaces 116 of the core 103. In this embodiment, the magnetic holding force is determined by the distance of the gap 121 set according to the position where the stopper 120 is arranged. The smaller the gap 121, the stronger the magnetic coercive force, and conversely, the larger the gap 121, the weaker the magnetic coercive force.

As described above in the first to third embodiments, the magnet driver 107 and the core 103
With respect to the relationship, the stronger the magnetic coercive force between them, the higher the stability of the magnet driver 107 at rest, but
The switching speed of the rotation direction is accordingly reduced. Conversely, the weaker the magnetic holding force, the lower the stability of the magnet driver 107 at rest, but the faster the switching speed in the rotation direction. Therefore, if the magnetic holding force is appropriately adjusted using the attraction force reducing means as shown in the above-described embodiment, the shutter opening / closing drive can be smoothly and quickly performed without requiring a large force.

Next, the shutter mechanism 102 operated by the electromagnetic driving device 101 will be described. As shown in FIGS. 1 and 2, the shutter mechanism 102 includes a disk-shaped base plate 109 having an exposure hole 108, a first shutter blade 110 for shielding the exposure hole 108, and a second shutter blade 110.
The shutter blade 111 and the first shutter blade 110
And the second shutter blade 111 has the magnet driver 107
And an operating lever 112 for transmitting power from the motor.

FIG. 8 shows a state when the shutter is closed. The power required for the magnet driver 107 to swing in the closing direction of the shutter is applied to the operating lever 11.
2, the first shutter blade 110 and the second shutter blade 111 overlap with each other, and
Block 08. FIG. 9 shows a state in which the shutter is opened. An operation in which the magnet driver 107 attempts to swing in the opening direction of the shutter is transmitted to the operating lever 112, and the first shutter blade 110 is accordingly actuated. And the second shutter blade 111 is separated from each other, and the exposure hole 108 is exposed from the openings of both shutter blades.

FIG. 10 shows an example of a configuration in which the shutter device 100 is mounted in a lens barrel of an optical device such as a video camera or a digital camera. The shutter device 100 is disposed in the camera body 130 in a state sandwiched between the front lens group 131 and the rear lens group 132. The front lens group 131 is disposed in the light receiving opening 134 of the camera body 130, and takes in light emitted from a subject. The taken-in light is received by the rear lens group 132 within a predetermined time by the two shutter blades 110 and 111 of the shutter device 100. This rear lens group 132
Is provided for focusing light on a predetermined portion of the light receiving body 133 (for example, a CCD or a photosensitive film). Shutter device 100
Is approximately the same diameter as the front lens group 131 and the rear lens group 132 and has a small thickness, and therefore fits easily in a narrow place between the front lens group 131 and the rear lens group 132. Further, since the driving mechanism is simple and driven by using the suction force reducing means, the movement is smooth and the power consumption is small.
For this reason, it is suitable for optical devices such as small video cameras and digital cameras.

Next, the exposure operation in the camera body 130 will be described. The camera body 130 is a digital camera in which a CCD is mounted on a photoreceptor 133, and has the following three modes of control as an exposure operation.
First, the first control utilizes the entire opening / closing operation of the shutter device 100, and is the most common and is suitable for a camera having a middle / low shutter speed. This operation is synchronized with the release operation of the camera, and the shutter blades 110, 111
Opens and closes, and during the opening and closing, makes the CCD expose,
The exposure signal is output. The second control uses only the opening operation of the shutter device 100 and is suitable for a high-speed operation with a shutter speed of 1/60 sec to 1/2000 sec. In this operation, the shutter blades 110 and 111 are opened in conjunction with the release operation of the camera, and the opening amounts of the shutter blades 110 and 111 are detected by a detecting means such as a photo interrupter during the opening operation. An exposure completion signal is output when the opening amount reaches a predetermined shutter time, and exposure to the CCD is interrupted and output based on the exposure completion signal. Third
Control uses only the closing operation of the shutter device 100, and as in the above case, the shutter speed is reduced to 1/6.
It is suitable for high-speed operation from 0 sec to 1/2000 sec. In this operation, after the shutter blades 110 and 111 are once set to the open state in conjunction with the release operation of the camera, the detection unit detects the opening amount of the shutter during the closing operation in synchronization with the close signal. An exposure completion signal is output when the shutter is closed to an opening amount at which a predetermined shutter time can be obtained. Based on the exposure completion signal, the exposure to the CCD is made valid, and light is received. The first to third controls described above can be appropriately combined depending on the performance of the shutter device 100.

In the above-described embodiment, the shutter device has been described as an application example of the electromagnetically driven light amount adjusting device. However, the present invention is not limited to such a shutter device. It is also applicable for driving.

[Brief description of the drawings]

FIG. 1 is a plan view showing a state in which an electromagnetic drive device according to the present invention is incorporated in a shutter device.

FIG. 2 is an exploded perspective view of the shutter device.

FIG. 3 is a partially enlarged plan view of the electromagnetic driving device.

FIG. 4 is an operation diagram for explaining the operation of the electromagnetic drive device.

FIG. 5 is a partially enlarged plan view of a first embodiment showing an attraction force reducing means in the electromagnetic driving device.

FIG. 6 is a partially enlarged plan view of a second embodiment showing an attraction force reducing means in the electromagnetic driving device.

FIG. 7 is a partially enlarged plan view of a third embodiment showing an attraction force reducing means in the electromagnetic driving device.

FIG. 8 is a plan view showing a state where the shutter blades in the shutter device according to the present invention are closed.

FIG. 9 is a plan view showing a state when shutter blades of the shutter device are opened.

FIG. 10 is a conceptual diagram when the shutter device is incorporated in an optical device such as a camera.

FIG. 11 is a perspective view showing a structure of a conventional diaphragm device.

FIG. 12 is a plan view of an electromagnetic drive unit in the diaphragm device.

[Explanation of symbols]

 103 core 105 coil 107 magnet driver 116, 117 suction surface

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/225 H04N 5/225 G // H04N 101: 00 101: 00

Claims (6)

[Claims] A magnet driver having both magnetic surfaces of an N pole and an S pole; a stator having an attraction surface facing each of the magnetic surfaces of the magnet driver to form a magnetic circuit;
A coil for magnetizing the stator and switching a magnetic polarity according to a direction of current flow, wherein an attraction force reducing means is provided between a magnetic surface of the magnet driver and an attraction surface of the stator. Drive. 2. The electromagnetic device according to claim 1, wherein said attraction force reducing means is a roughened surface provided on one of a magnetic surface of a magnet driving body and an attraction surface of a stator. Drive. 3. The non-magnetic member according to claim 1, wherein the attraction force reducing means is a sheet-shaped non-magnetic member provided on one of a magnetic surface of a magnet driving body and an adsorption surface of a stator. Electromagnetic drive. 4. A gap formed when the magnetic surface maintains a direction facing the attracting surface of the stator due to the rotation of the magnet driver, and a magnet drive unit for holding the gap. 2. The electromagnetic drive device according to claim 1, further comprising a stopper for preventing rotation. 5. A magnet driver having both N-pole and S-pole magnetic surfaces, a stator having an attraction surface opposed to both magnetic surfaces of the magnet driver and forming a magnetic circuit,
A light quantity adjusting device that is driven to open and close using an electromagnetic drive device that has a coil that magnetizes the stator and switches the magnetic polarity according to the direction of current flow, wherein the electromagnetic drive device includes a magnetic surface of the magnet driver and a stator. An electromagnetically driven light amount adjusting device, comprising: an attraction force reducing unit configured to reduce an attraction force between the attraction surface and the attraction surface. 6. A magnet driver having both magnetic surfaces of an N pole and an S pole, a stator having an attraction surface facing each of the magnetic surfaces of the magnet driver and forming a magnetic circuit,
A light quantity adjusting device that is opened and closed using an electromagnetic drive device having a coil that magnetizes the stator and switches the magnetic polarity according to the direction of current flow, and an electromagnetically driven light quantity adjusting device that incorporates the light quantity adjusting device. An optical device comprising an optical lens system, wherein the electromagnetic driving device includes an attraction force reducing unit configured to reduce an attraction force between a magnetic surface of the magnet driving body and an attraction surface of the stator. Optical equipment using an electromagnetically driven light amount adjustment device.