JP2004205967A - Light quantity adjusting device and optical equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light quantity adjusting device whose light shielding member can efficiently be driven while the device is made small-sized on the whole. <P>SOLUTION: Provided are a driving unit which has a rotor magnet 2, a stator yoke 4, and a coil unit 5, a light shielding member 3 which is fitted to the rotor magnet 2 and moves to and away from a light passage opening as the rotor magnet 2 rotates, a device substrate 1 which supports the light shielding member 3 rotatably, and a pressure member 6 which secures a travel space for the light shielding member 2, and the device substrate 1 and pressure member 6 clamp and support the driving unit. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light amount adjusting device used for an optical device such as a camera.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a shutter device that uses a moving magnet type electromagnetic drive unit as a drive source for a shutter blade or the like (for example, see Patent Document 1).
[0003]
2. Description of the Related Art In recent years, there is a strong demand for miniaturization (thinning) of optical devices such as a video camera and a still camera equipped with a light amount adjusting device, and a downsizing of the light amount adjusting device necessarily disposed in the optical device is also required. .
[0004]
Here, in a camera provided with a lens barrel, the light amount adjusting device is disposed in a cylindrical lens barrel together with a lens driving mechanism (including a lens driving source) for performing focusing and zooming. Therefore, in order to reduce the size of the camera (the size of the lens barrel in the radial direction), there is a demand that the light amount adjusting device and the like be housed within a small diameter centered on the optical axis.
[0005]
In addition, when miniaturizing the camera (reducing the size of the lens barrel in the direction of the optical axis), the distance from the light amount adjusting device to the imaging medium (imaging element such as film or CCD) or the lens driving source However, in order to prevent interference between the members, there is a demand to reduce the thickness (length in the optical axis direction) of the light amount adjusting device.
[0006]
Here, by using a rotor magnet made of a high magnetic material such as a neodymium (Nd-Fe-B) magnet as the permanent magnet, the drive unit can be downsized and the shutter device as a whole can be downsized.
[0007]
This shutter device has a rotor magnet magnetized to two poles (N pole and S pole) on the outer peripheral surface of a small and high-performance permanent magnet, and a stator yoke arranged on the outer periphery of the rotor magnet. Driving (opening / closing operation) of the shutter blades is performed by using an attractive force and a repulsive force generated between the rotor magnet and the stator yoke by energizing the electromagnetic coil.
[0008]
[Patent Document 1]
JP-A-5-216090
[Problems to be solved by the invention]
However, when the size of the drive unit is reduced, the attraction force and repulsion force generated between the permanent magnet and the magnetic stator yoke cannot be increased. In a configuration in which a power transmission member such as a driving lever is disposed between the driving source and the shutter blade, the driving force from the driving source is not efficiently transmitted to the shutter blade or the like, and the driving of the shutter blade or the like is unstable. May become
[0010]
On the other hand, in order to transmit the necessary driving force to the shutter blades, it is necessary to increase the power supplied to the driving unit (electromagnetic coil). However, in this case, the power consumption increases. For this reason, it has been difficult to achieve both miniaturization and low power consumption of the light amount adjusting device.
[0011]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a light amount adjusting device capable of appropriately driving shutter blades and the like without increasing the drive current while reducing the size.
[0012]
[Means for Solving the Problems]
A light quantity adjusting device according to the present invention includes a rotatable rotor magnet that is magnetized on an outer circumferential surface thereof, a rotatable rotor magnet, a stator yoke arranged to face the outer circumferential surface of the rotor magnet, and a coil unit that excites the stator yoke by energization. A light shielding member attached to the rotor magnet and capable of moving back and forth with respect to the light passage opening in accordance with the rotation of the rotor magnet, a device substrate rotatably supporting the light shielding member, and running of the light shielding member. A holding member for securing a space, wherein the device substrate and the holding member sandwich and support the drive unit.
[0013]
That is, by supporting the drive unit by sandwiching it between the device substrate and the holding member, the entire light amount adjusting device can be made smaller (thinner). Specifically, since a member for supporting the drive unit is not required, the size can be reduced by reducing the number of components.
[0014]
Moreover, by attaching a light shielding member to the rotor magnet, the rotational force of the rotor magnet is directly transmitted to the light shielding member, which is compared with a case where a power transmission member such as a drive lever is arranged between the rotor magnet and the light shielding member. The power from the drive unit is efficiently transmitted to the light shielding member. As a result, it is not necessary to supply a large current to the coil unit as in the above-described related art, and power saving can be achieved.
[0015]
Here, the drive unit can be arranged so as to substantially fit within the thickness of the apparatus main body.
[0016]
As a configuration in which the drive unit is sandwiched between the device substrate and the holding member, in a coil unit having a bobbin and a coil wound around the bobbin, the bobbin is formed with a flange portion sandwiched between the device substrate and the holding member. Can be.
[0017]
Here, if the flange portion is formed at a position separated from the both end surfaces of the bobbin (end surfaces facing in the thickness direction of the light amount adjusting device) by substantially the thickness of the device substrate and the pressing member, the surface of the light amount adjusting device is formed. Flattening can be achieved without unevenness.
[0018]
The light amount adjusting device of the present invention can be mounted on optical devices such as cameras and portable electronic devices. As described above, if the light amount adjusting device capable of downsizing is mounted on an optical device, the entire optical device can be downsized.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
Hereinafter, a shutter device (light amount adjusting device) according to a first embodiment of the present invention will be described with reference to the drawings.
[0020]
FIG. 1 is an exploded perspective view of the shutter device, and FIG. 2 is a plan view of the shutter device. 3 is a sectional view taken along line AA in FIG. 2, and FIG. 4 is a sectional view taken along line BB in FIG. FIG. 7 is a schematic diagram of a camera (optical device) including the shutter device of the present embodiment.
[0021]
Note that the shutter device of the present embodiment can also be mounted on a lens device (optical device) detachable from the camera body, a portable electronic device (mobile phone, optical device) with a built-in camera, and the like.
[0022]
In FIG. 7, reference numeral 10 denotes a camera body, in which various members capable of photographing are arranged. Reference numeral 11 denotes a photographing lens arranged in the camera main body 10, and passes a subject light beam. Here, the photographing lens 11 is composed of a plurality of lens groups, and the optical zoom can be performed by changing the distance of these lens groups in the optical axis direction.
[0023]
Reference numeral 12 denotes a shutter device, which shields a subject light beam that has passed through the photographing lens 11. The specific configuration of the shutter device 12 will be described later. Reference numeral 13 denotes an image pickup medium, which is constituted by an image pickup device such as a CCD or a CMOS. Note that a film can be used as the imaging medium 13.
[0024]
The imaging medium 13 receives (exposes) a subject light beam that has passed through the photographing lens 11. As a result, an image signal corresponding to the amount of received light is output from the image pickup medium (image pickup device) 13, the image signal is subjected to predetermined image signal processing, and then a display unit (not shown) provided on the camera body 10. Is displayed as a subject image. The data of the subject image can be recorded on a recording medium (not shown) (for example, a CompactFlash (registered trademark) card) inserted into the camera body 10.
[0025]
The camera body 10 is provided with an operation unit for starting a photographing operation, and photographing (imaging) can be performed by operating the operation unit by a photographer.
[0026]
Next, the configuration of the shutter device 12 will be described with reference to FIG.
[0027]
Reference numeral 1 denotes a shutter base plate (apparatus board) to which members described below are attached. In the center of the shutter base plate 1, an opening 1d serving as a light passage port is formed.
[0028]
Reference numeral 2 denotes a rotor magnet composed of a permanent magnet, and its outer peripheral surface is magnetized to two poles (N pole, S pole).
[0029]
Reference numeral 3 denotes a shutter blade (light shielding member), on which rotating shafts 3a and 3b extending in a direction perpendicular to the blade running surface are integrally formed on the front and back surfaces. The rotor magnet 2 is press-fitted into the rotating shaft 3b to be integrally formed. Here, the rotating shaft 3b and the rotor magnet 2 may be integrally formed by insert molding or two-color molding.
[0030]
The rotating shaft 3a is rotatably engaged with a bearing hole 6a formed in a blade holding plate (holding member) 6, which will be described later. The rotating shaft 3b is rotatably engaged with a bearing hole 1a formed in the shutter base plate 1.
[0031]
Reference numeral 4 denotes a stator yoke made of a soft magnetic material, which is formed in a horseshoe shape. The stator yoke 4 has magnetic pole portions 4a and 4b arranged to face the outer peripheral curved surface of the rotor magnet 2. The stator yoke 4 is attached to the shutter base plate 1 from the blade attachment side (upper side in FIG. 1) together with an electromagnetic coil unit 5 described later.
[0032]
Reference numeral 5 denotes an electromagnetic coil unit, which is configured by winding a coil made of a conductive wire around a bobbin 5a. The electromagnetic coil unit 5 is attached to the shutter base plate 1 in a state where one or a plurality of stacked stator yokes 4 are inserted.
[0033]
Reference numeral 6 denotes a blade holding plate, which is attached to the shutter base plate 1 at a predetermined interval. Thereby, the blade holding plate 6 protects the shutter blade 3 and secures a running space for the shutter blade 3. In the center of the blade holding plate 6, an opening 6c serving as a light passage port is formed.
[0034]
At the time of assembling the shutter device 12, the corner portions 6b of the blade holding plate 6 come into contact with the flange portions 5b and 5c of the bobbin 5a, and the electromagnetic coil unit 5 and the stator yoke 4 connect the blade holding plate 6 and It is fixed while being sandwiched by the shutter base plate 1.
[0035]
Here, the upper surfaces of the flange portions 5b and 5c (upper surfaces in FIG. 1) are located below the upper surface of the electromagnetic coil unit 5 by the thickness of the blade holding plate 6, and the shutter device 12 is assembled. In this state, the upper surface of the blade holding plate 6 and the upper surface of the electromagnetic coil unit 5 are located in substantially the same plane as shown in FIGS.
[0036]
The lower surfaces of the flange portions 5b and 5c (the lower surfaces in FIG. 1) are located above the lower surface of the electromagnetic coil unit 5 by the thickness (x) of the shutter base plate 1, and the shutter device 12 In the assembled state, the lower surface of the shutter base plate 1 and the lower surface of the electromagnetic coil unit 5 are located in substantially the same plane as shown in FIGS.
[0037]
In the above configuration, as shown in FIGS. 3 and 4, the electromagnetic coil unit 5 fits within the thickness of the shutter device 12.
[0038]
Further, since the rotor magnet 2 is directly fixed to the rotating shaft 3 b formed integrally with the shutter blade 3, the rotational force of the rotor magnet 2 can be directly transmitted to the shutter blade 3. For this reason, the power from the drive source can be transmitted to the shutter blade 3 more efficiently than when the rotational force of the rotor magnet 2 is transmitted to the shutter blade via a power transmission member such as a drive lever (prior art). As a result, the shutter blades 3 can be driven at high speed.
[0039]
The electromagnetic coil unit 5 (stator yoke 4) is fixed with the flange portions 5b and 5c sandwiched between the blade holding plate 6 (corner portion 6b) and the shutter base plate 1, so that the electromagnetic coil unit 5 (stator yoke 4) is fixed. A member (for example, a screw) for fixing the stator yoke 4) to the shutter base plate 1 becomes unnecessary. By reducing the number of components in this way, the cost of the shutter device 12 can be reduced, and the shutter device 12 can be made smaller (thinner).
[0040]
Moreover, by configuring the actuators of the shutter blades 3 (the rotor magnet 2, the electromagnetic coil unit 5, and the stator yoke 4) so as to be within the thickness of the shutter device 12, compared with the shutter device and the like disclosed in Patent Document 1. Thus, the shutter device can be reduced in size (thickness).
[0041]
That is, in the shutter device 12 according to the present embodiment, the shutter blades 3 can be efficiently driven without increasing the power supplied to the electromagnetic coil unit 5 as described above, and the overall size of the device is reduced. Can be.
[0042]
Next, a method of assembling the shutter device 12 according to the present embodiment will be described.
[0043]
First, the electromagnetic coil unit 5 into which the stator yoke 4 has been inserted is assembled into the shutter base plate 1. Then, the rotor magnet 2 with which the shaft portion 3b is engaged is arranged in the space between the magnetic pole portions 4a and 4b of the stator yoke 4. At this time, the rotary shaft 3b is arranged so as to fit into the bearing hole 1a of the shutter base plate 1.
[0044]
Then, the blade holding plate 6 is attached to the shutter base plate 1. At this time, the blade holding plate 6 is attached so that the rotating shaft 3a fits into the bearing hole 6a of the blade holding plate 6. Thus, the shutter device 12 is assembled.
[0045]
In the shutter device 12 of the present embodiment, since all the components constituting the shutter device 12 can be attached to the shutter base plate 1 from one side (upper side in FIG. 1), assembly of the shutter device 12 becomes easy.
[0046]
Next, the operation of the shutter device 12 having the above-described configuration will be described.
[0047]
When the electromagnetic coil unit 5 is in the power OFF state, the stator yoke 4 is in a non-excited state, and the rotor magnet 2 is moved to a predetermined position (detent force) by an attractive force (detent force) with the magnetic pole portions 4a and 4b of the stator yoke 4. 2).
[0048]
At this time, the shutter blade 3 is held in a state of being in contact with the stopper 1c formed on the shutter base plate 1, and is in a state of being retracted from the opening 6c of the blade holding plate 6 (open state).
[0049]
In the state shown in FIG. 2, when the energization (positive energization) of the electromagnetic coil unit 5 is controlled so that the magnetic pole portion 4a of the stator yoke 4 becomes the S pole and the magnetic pole portion 4b becomes the N pole, the stator yoke 4 and the rotor Attraction and repulsion are generated between the magnet 2 and the rotor magnet 2, and the rotor magnet 2 rotates counterclockwise at an angle of about 40 ° to 50 ° from the state of FIG.
[0050]
Thus, the shutter blade 3 moves from the open state to a position covering the opening 6c.
[0051]
Here, the rotor magnet 2 and the stator yoke 4 have zero detent force at an intermediate position (approximately 20 ° to 25 °) in the entire operating range (angle of 40 ° to 50 °) of the rotor magnet 2 and have a low detent force. It is arranged so that the direction is switched right and left (reverse direction) before and after the intermediate position.
[0052]
With this arrangement, the shutter blades 3 are formed on the shutter base plate 1 by the detent force even when the power is turned off after the electromagnetic coil unit 5 is energized to rotate the shutter blades 3. And remains in contact with the stopper 1b. That is, the shutter blades 3 are held so as to cover the opening 6 c of the blade holding plate 6.
[0053]
On the other hand, if the energization (reverse energization) control of the electromagnetic coil unit 5 is performed so that the magnetic pole part 4a of the stator yoke 4 becomes the N pole and the magnetic pole part 4b becomes the S pole, the gap between the stator yoke 4 and the rotor magnet 2 is obtained. A repulsive force and an attractive force are generated, and the rotor magnet 2 rotates clockwise in FIG. 2 at an angle of about 40 ° to 50 °, and returns to the initial position (the position shown in FIG. 2).
[0054]
When the electromagnetic coil unit 5 is turned off, the shutter blade 3 is held in the state shown in FIG. 2 by the detent force between the rotor magnet 2 and the stator yoke 4.
[0055]
As described above, the shutter blade 3 receives the two forces of magnetic attraction and repulsion of the rotor magnet 2 and the stator yoke 4 by forward and reverse energization of the electromagnetic coil unit 5, and the shutter blades 3 move the rotating shafts 3a and 3b. The opening 6c that rotates as the center and serves as a light passage opening is opened and closed.
[0056]
Further, after the power supply to the electromagnetic coil unit 5 is cut off, the shutter blades 3 abut against the stopper portion 1b or the stopper portion 1c due to the detent force generated between the rotor magnet 2 and the stator yoke 4. (Stop.
[0057]
When the shutter device 12 of the present embodiment is mounted on a digital camera in which the imaging medium 13 is formed of an imaging device such as a CCD, the shutter blades 3 are controlled by controlling the forward and reverse energization of the electromagnetic coil unit 5. Will be controlled. When the shutter device 12 of the present embodiment is mounted on a camera in which the imaging medium 13 is formed of a film, the drive of the shutter blades 3 is controlled by the energizing time and energizing timing of the electromagnetic coil unit 5. become.
[0058]
(2nd Embodiment)
Hereinafter, a shutter device according to a second embodiment of the present invention will be described with reference to FIGS. Here, FIGS. 5 and 6 are partial cross-sectional views of the shutter device of the present embodiment.
[0059]
The shutter device of the present embodiment has substantially the same configuration as the shutter device described in the first embodiment. Hereinafter, portions different from the first embodiment will be described. The same members as those described in the first embodiment are denoted by the same reference numerals.
[0060]
In the first embodiment, the rotating shafts 3 a and 3 b are integrally formed with the shutter blade 3, and the rotating shafts 3 a and 3 b can be rotated to the bearing hole 1 a of the shutter base plate 1 and the bearing hole 6 a of the blade holding plate 6, respectively. It is engaged in the state.
[0061]
On the other hand, in the present embodiment, as shown in FIG. 5, a rotary shaft 1e is formed on the shutter base plate 1, and the rotary shaft 1e engages with a cylindrical bearing hole 3c formed on the shutter blade 3. are doing. As a result, the shutter blade 3 becomes rotatable about the rotation shaft 1e.
[0062]
The rotor magnet 2 is integrally mounted on the outer peripheral surface of the bearing hole 3c by press fitting. The bearing hole 3e and the rotor magnet 2 may be integrally formed by insert molding or two-color molding.
[0063]
FIG. 6 shows a modification of the shutter device of the present embodiment.
[0064]
In the figure, a rotating shaft 1e is formed on the shutter base plate 1, and the rotating shaft 1e is adapted to engage with the inner peripheral surface 2a of the rotor magnet 2. The rotor magnet 2 is made of a plastic magnet having good slidability, and is integrally attached to the shutter blade 3 by two-color molding.
[0065]
Since the rotor magnet 2 is made of a plastic magnet having good slidability, the frictional force between the rotating shaft 1e and the inner peripheral surface 2a can be reduced, and the shutter blades 3 can be driven efficiently.
[0066]
The same effects as in the first embodiment can be obtained with the configuration as shown in FIGS. 5 and 6.
[0067]
Although the shutter device has been described in the first and second embodiments, the present invention can also be applied to a diaphragm device having aperture blades and a device having aperture blades and shutter blades.
[0068]
In the case of the aperture device, in the configuration of the shutter device shown in FIG. 1, instead of the shutter blade 3, an aperture blade having an opening smaller in diameter than the diameter of the opening 6c can be used. In the configuration of the aperture device, when the opening formed in the aperture blade is made to enter the opening 6c of the blade holding plate 6, the light amount of the subject light beam can be limited.
[0069]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the light quantity adjustment apparatus of this invention, while reducing the whole apparatus, the light-shielding member can be driven efficiently, without increasing the electric power supplied to a coil unit.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a shutter device according to a first embodiment.
FIG. 2 is a plan view of the shutter device according to the first embodiment.
FIG. 3 is a cross-sectional view of the shutter device according to the first embodiment (a cross-sectional view along AA in FIG. 2).
FIG. 4 is a cross-sectional view of the shutter device according to the first embodiment (a cross-sectional view taken along line BB in FIG. 2).
FIG. 5 is a partial cross-sectional view of a shutter device according to a second embodiment.
FIG. 6 is a partial cross-sectional view (modification example) of a shutter device according to a second embodiment.
FIG. 7 is a schematic diagram of a camera including a shutter device according to the first embodiment.
[Explanation of symbols]
1: Shutter base plate 2: Rotor magnet 3: Shutter blade 3a, 3b: Rotating shaft 4: Stator yoke 5: Electromagnetic coil unit 5a: Bobbin 5b, 5c: Flange part 6: Blade holding plate 6a: Bearing hole

Claims (5)

A rotor unit that is multipolarly magnetized on the outer peripheral surface and is rotatable, a rotor yoke, a stator yoke disposed to face the outer peripheral surface of the rotor magnet, and a coil unit that energizes the stator yoke when energized; A light-shielding member attached to the rotor magnet and capable of moving forward and backward with respect to the light passage opening in accordance with the rotation of the rotor magnet,
An apparatus substrate rotatably supporting the light shielding member;
A holding member for securing a running space for the light shielding member,
The light amount adjusting device, wherein the device substrate and the pressing member sandwich and support the drive unit. The light amount adjusting device according to claim 1, wherein the drive unit is disposed so as to substantially fit within a thickness of the device main body. The coil unit has a bobbin and a coil wound around the bobbin,
The light amount adjusting device according to claim 1, wherein the bobbin has a flange portion sandwiched between the device substrate and the pressing member. 4. The light amount adjusting device according to claim 3, wherein the flange portion is formed at a position apart from both end surfaces of the bobbin by substantially the thickness of the device substrate and the pressing member. 5. An optical apparatus comprising the light amount adjusting device according to claim 1.

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