JP2008026692A - Shutter apparatus for digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shutter apparatus for a digital camera where, in two shutter blades rotating to opposite directions, even if at least either is composed of two divided blades, an closing operation by an electromagnetic actuator can be stably performed at a high speed. <P>SOLUTION: A driving member 7 integrated into a rotor 6 made of a permanent magnet comprises a driving pin 7b at the tip of an arm part 7a. The driving member 8 rotatably fitted to the rotor 6 comprises a driving pin 8b at the tip of an arm part 8a. A shutter blade 3 is fitted to a blade shaft 1b, and shutter blades 4, 5 are fitted to a blade shaft 1c. The driving pin 7b is inserted into the long hole 4a of the shutter blade 4, and the driving pin 8b is inserted into the long holes 3a, 5a of the shutter blades 3, 5. Then, a torsion coil spring 9 is applied between the two driving members 7, 8 for rotation to opposite directions, thus only the shutter blade 4 is operated in the initial stage of the closing operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a shutter device suitable for use in a digital camera.

  Among the shutter devices employed in recent digital cameras, two shutter blades that are rotatably attached to the main plate are simultaneously reciprocated in opposite directions by electromagnetic actuators. is there. As the electromagnetic actuator, many current-controlled electromagnetic actuators that are easy to miniaturize at low cost are employed. The rotor provided in this type of electromagnetic actuator is formed of a permanent magnet having a substantially columnar shape (or a substantially cylindrical shape) and magnetized in a radial direction with two poles (or four poles). The rotor is integrated with a driving means made of synthetic resin, and the driving pin is usually formed at the tip end of the rotor extending in the substantially radial direction. It is also known that these are not made of synthetic resin and are integrally formed with a permanent magnet together with a rotor. The rotor can reciprocate only within a predetermined rotation angle range corresponding to the direction of current supplied to the stator coil, and is recently provided in the driving means. In general, the drive pin is directly connected to the two blades.

  Also, various types of stators of this type of electromagnetic actuator are known. However, what is actually implemented a lot can be roughly divided into two types. One of them is equipped with a substantially U-shaped yoke with the tips of the two leg portions as magnetic pole portions. A stator coil is wound around one of the leg portions, and the two magnetic pole portions are placed on the circumferential surface of the rotor. The other is configured so that the rotor is housed in a housing chamber formed in a cylindrical space by two stator frames, and the stator frames are enclosed so as to surround the housing chamber. The stator coil is configured to be wound around the outside. In Patent Document 1 below, there are different implementations of shutter devices in which two electromagnetic actuators having respective stator configurations cause two shutter blades to open and close by the drive pins as described above. It is described as an example.

  On the other hand, recent shutter devices for digital cameras are required to be further miniaturized from the viewpoint of increasing the number of components accompanying the multi-functionality of the camera and improving the portability of the camera. In order to satisfy the above, it is of course necessary to reduce the size of the electromagnetic actuator as described above, but it is also necessary to reduce the size of the ground plane by reducing the accommodation space of the shutter blades when the exposure opening is fully opened. Become. In order to reduce the storage space for the shutter blades, at least one of the two shutter blades described above is composed of blades divided into two, and when fully opened, It is known from Patent Document 2 below that it is only necessary to accommodate a large amount of each other. Moreover, it can be said that such a configuration of the shutter blade is an advantageous configuration even when it is desired to increase the exposure opening without increasing the size of the base plate.

  In the present invention, among the two shutter blades that are simultaneously rotated in opposite directions, at least one of the shutter blades is divided into two to make a total of three or more blades as described above. The present invention relates to a shutter device for a digital camera that is opened and closed by an electromagnetic actuator.

JP 2005-241866 A JP-A 64-526

  In the case of a digital camera equipped with the shutter device described in Patent Document 1, the shutter blade is normally set at a shooting standby position (initial position) at a position where the exposure opening is fully opened, and shooting is started in that state. The shutter blades can be closed at the end of photographing. After that, when imaging information is transferred from the solid-state imaging device to the storage device, the shutter blades are opened and returned to the imaging standby position. As can be understood from this, in the case of a digital camera, it can be said that the closing operation is more important than the opening operation for the shutter blade. The closing operation is required to be performed stably at high speed so as not to cause uneven exposure and uneven cutting.

  By the way, as described above, the current control type electromagnetic actuator described in Patent Document 1 is characterized in that it is easy to miniaturize at a low cost. However, compared to a step motor, the startability is somewhat difficult. Therefore, if the weight of the shutter blade increases, the startability also decreases, and the exposure opening is closed after the shutter blade starts to close. It takes a long time to do it or it becomes unstable. On the other hand, the shutter blade is at least one of the two shutter blades as described in Patent Document 2 in order to reduce the size of the shutter device and to cope with an increase in the diameter of the exposure opening. If one side is divided into two sheets, these divided blades must be overlapped with each other when the exposure opening is closed. Will become bigger.

  Therefore, when the shutter device described in Patent Document 1 is employed in a digital camera, it is described in Patent Document 2 in order to reduce the size of the shutter device or enlarge the exposure opening. In addition, when dividing at least one of the two shutter blades into two, even if the number of blades increases and the weight increases, the effect of the shutter blades is hardly affected. It is required that the closing operation be performed at high speed and stably.

  The present invention has been made to solve such a problem, and the object of the present invention is to, among two shutter blades that simultaneously rotate in opposite directions to open and close the exposure aperture, To provide a shutter device for a digital camera in which the closing operation of the exposure aperture can be obtained at high speed and stably by the electromagnetic actuator even if at least one is constituted by two divided blades.

  In order to achieve the above object, a shutter device for a digital camera according to the present invention includes a ground plate having an opening for a photographing optical path, a permanent magnet, and reciprocally rotates in accordance with the energization direction to the stator coil. And a first drive means integrated with the rotor and having a first drive pin at a tip end portion extending in a substantially radial direction of the rotor, and separate from the rotor. A second driving means that is arranged to be rotatable about a rotation axis of the rotor and has a second driving pin at a tip end portion extending in a substantially radial direction of the rotor; and the first driving means. And a biasing means that biases the second driving means to rotate in a relatively opposite direction, and a relative angle between the first driving means and the second driving means is the biasing force of the biasing means. Restriction means to limit the angle so that it does not exceed a predetermined angle by force, A first blade that is rotatably attached to the main plate and rotated by the first drive pin when the first driving means rotates, and a second blade that is rotatably attached to the main plate. A second blade that is rotated in a direction opposite to the first blade by the second drive pin when the device rotates in the same direction as the first drive device, and is rotatably attached to the base plate; A third blade that is simultaneously rotated in a direction opposite to the second blade by the second drive pin when the second drive device rotates in the same direction as the first drive device, When closing, only the first driving means is rotated until the relative angle between the first driving means and the second driving means reaches the predetermined angle.

  In this case, the second blade is rotatably attached to the ground plate at a position different from the first blade, and the third blade is the same position as the first blade with respect to the ground plate. It is advantageous to make the base plate smaller because the number of blade attachment points is small. Further, it is rotatably attached to the base plate at the same position as the second blade, and when the first driving means rotates, it is simultaneously rotated in the direction opposite to the first blade by the first driving pin. When the fourth blade is provided, it is advantageous to further reduce the size of the main plate.

  Further, when the second driving means is rotatably attached to the rotor, it is advantageous in assembly. The biasing means is a torsion coil spring, and it is practical if one arm portion is hooked on the first driving means and the other arm portion is hooked on the second driving means. In this case, however, the torsion coil spring is advantageous in terms of assembly if the coil portion is wound around the rotor. Further, the first drive pin and the second drive pin are made of permanent magnets, and since they constitute the biasing means, they are magnetized so that their opposing surfaces have the same polarity. Then, the torsion coil spring as described above becomes unnecessary. Further, the first driving means of the present invention may be made of a permanent magnet together with the rotor.

  When performing the closing operation of the shutter device of the present invention, in the initial stage where the rotational force of the rotor is not sufficiently large, the second blade and the third blade are not loaded on the rotor. Only one blade is immediately started to close, and then the exposure opening starts to close and the second blade and the third blade start to close when the rotational force of the rotor increases. Therefore, there is an advantage that the timing at which the opening of the exposure opening is started is stabilized and the time from when the first blade starts closing the exposure opening until the exposure opening is completely closed is shortened. It is extremely effective as a device.

  The embodiment of the present invention will be described with reference to two illustrated examples. The present invention can also be applied to a shutter device configured as a single unit together with a diaphragm device and a filter device. However, in each of the embodiments, the shutter device is unitized alone. It will be explained as a thing. 1 to 5 are for explaining the first embodiment, and FIG. 6 is for explaining the second embodiment.

  First, Example 1 will be described with reference to FIGS. 1 to 5. FIG. 1 is a plan view showing a photographing standby state, and FIG. 2 shows a state in the middle of a shutter blade closing operation. FIG. 3 is a plan view showing an end state of the shutter blade closing operation. 4 (a) to 4 (f) are diagrams for explaining a specific mounting configuration of the two driving means with respect to the rotor. FIGS. 5 (a) and 5 (b) It is a figure for demonstrating the relative positional relationship of two drive means mainly at the time of an action | operation.

  First, the configuration of this embodiment will be described with reference to FIGS. The ground plane 1 is formed with a relatively thick synthetic resin, and has a circular opening 1a and an arc-shaped long hole (not shown) which will be described later. A cover plate 2 having the same outer shape is attached to the base plate 1 on the front side in FIG. 1 by an appropriate means (not shown), and constitutes a blade chamber between the base plate 1 and A part of the cover plate 2 is shown only in FIG. 1 for easy understanding of the configuration of the blade chamber, and is not shown in FIGS. 2 and 3. The cover plate 2 is also formed with an opening 2a having the same size so as to overlap the opening 1a.

  On the base plate 1, two blade shafts 1b, 1c and three stopper shafts 1d, 1e, 1f are erected. The distal end of the stopper shaft 1d is inserted into the hole 2b of the cover plate 2, and the other shafts 1b, 1c, 1e, and 1f are also formed in the cover plate 2 through holes that are not shown. Is inserted in each. Further, three shutter blades 3, 4, and 5 are arranged in the blade chamber. Among them, the shutter blade 3 arranged on the first base plate 1 side has a long hole 3a and a hole 3b having a unique shape, and is rotatably attached to the blade shaft 1b. The shutter blade 4 arranged in the middle has a long hole 4a and is rotatably attached to the blade shaft 1c. Further, the shutter blade 5 arranged on the cover plate 2 side has a long hole 5a and a hole 5b having a unique shape, and is rotatably attached to the blade shaft 1c together with the shutter blade 4.

  An electromagnetic actuator is attached to the surface outside the blade chamber of the main plate 1, and the rotor 6 is a cylindrical permanent magnet that is magnetized in two radial directions, and is erected on the main plate 1. It is rotatably attached to the shaft 1g. Then, the member integrated with the rotor 6 and the member attached to the rotor 6 are demonstrated concretely using FIG.4 and FIG.5. As shown in the plan view of FIG. 4 (a) and the side view of FIG. 4 (b), the rotor 6 has a small diameter portion formed at one end in the axial direction thereof, which is made of a synthetic resin material. The drive member 7 is integrally formed. In the drive member 7, a drive pin 7b and a spring hook pin 7c are erected at the distal end portion of the arm portion 7a extending in the radial direction.

  Further, another driving member 8 shown in the plan view of FIG. 4C and the side view of FIG. 4D is made of synthetic resin, and is an arm portion 8a extending in the radial direction from the annular portion. A driving pin 8b and a spring hooking pin 8c are erected at the front end portion, and a regulating pin 8d is erected at the annular portion. The drive member 8 has its annular portion rotatably fitted to the rotor 6 as shown in the plan view of FIG. 4E and the side view of FIG. ing. Further, as shown in FIG. 5, the rotor 6 is wound with a torsion coil spring 9 after the annular portion of the drive member 8 is fitted, and one arm portion of the rotor 6 is connected to the drive member. The other arm portion is hooked on the spring hook pin 8 c of the drive member 8. Therefore, the drive members 7 and 8 are urged so as to rotate in opposite directions by the torsion coil spring 9, and as shown in FIG. By abutting against the regulating pin 8d of the drive member 8, the mutual angular positional relationship is not changed.

  Although not shown, the base plate 1 is formed with an arc-shaped long hole centered on the shaft 1g, and the cover plate 2 has the same shape corresponding to the long hole. A long hole is formed. The two drive pins 7b and 8b are inserted into the blade chamber through the long hole of the base plate 1, and their tips are inserted into the long holes of the cover plate 2. 7b is inserted into the hole 3b of the shutter blade 3, the long hole 4a of the shutter blade 4 and the hole 5b of the shutter blade 5 in this order. It is inserted into the hole 5a.

  On the other hand, although not shown because it is well known, the stator of the electromagnetic actuator is substantially the same as the configuration described in FIG. 6 and FIG. In other words, a yoke having a substantially U-shape is opposed to the circumferential surface of the rotor 6 with the tip ends of the two legs as magnetic poles, and against the stator coil wound around one leg. When the current is supplied in the forward direction, the rotor 6 is rotated in the counterclockwise direction in FIG. 1, and then when the current is supplied in the reverse direction, the rotor 6 is rotated in the clockwise direction. ing. When no current is supplied to the stator coil, the rotor 6 is moved to either one by the attractive force of the permanent magnet acting between the magnetic pole portion of the yoke and the magnetic pole of the rotor 6. It is comprised so that the force to rotate may be provided.

  Next, the operation of this embodiment will be described. FIG. 1 shows a photographing standby state in which the shutter blades 3, 4, 5 fully open the opening 1 a, and at this time, the shutter blades 4, 5 are maximized in mutual overlap. In this state, since the subject light strikes the solid-state image sensor, the photographer can observe the subject image on the liquid crystal display device. At this time, no current is supplied to the stator coil, but as described above, the rotor 6 has a relative position between the magnetic pole of the permanent magnet and the two magnetic pole portions of the yoke (not shown). Depending on the relationship, a clockwise rotational force is applied. However, since the shutter blade 3 is in contact with the stopper shaft 1e and the shutter blades 4 and 5 are in contact with the stopper shaft 1f, this stopped state is maintained. Further, in this state, the rotational force applied to the rotor is greater than the biasing force of the torsion coil spring 9 shown in FIG. 5, and therefore the torsion coil spring 9 is tensioned. As shown in FIG. 5A, the arm portion 7 a of the drive member 7 is separated from the restriction pin 8 d of the drive member 8. In FIG. 1, only the relative angular positional relationship between the drive member 7 and the drive member 8 in such a state is shown.

  When the release button is pressed at the time of shooting, the charge accumulated in the solid-state image sensor is released, and immediately after that, charge accumulation for shooting is started. Then, when a predetermined time elapses, the stator coil is energized in the forward direction. Thereby, the rotor 6 starts to rotate counterclockwise in FIG. 1, but the rotational force in the initial stage is not so large. However, in the case of the present embodiment, in the state of FIG. 1, the urging force of the torsion coil spring 9 acts to push the drive pin 7b of the drive member 7 and rotate the rotor 6 counterclockwise. Therefore, the rotor 6 can rotate stably at high speed in the counterclockwise direction. At this stage, since the driving member 8 is biased to rotate clockwise by the torsion coil spring 9, the shutter blades 3 and 5 are not rotated, and only the shutter blade 4 is rotated clockwise. Will be. Therefore, at this stage, only the shutter blade 4 becomes a load on the rotor 6, so that the rotor 6 can rotate at high speed and stably.

  When the shutter blade 4 starts to close the opening 1a and enters the state shown in FIG. 2, the arm 7a of the drive member 7 is restricted by the drive member 8 as shown in FIG. It contacts the pin 8d. Therefore, at this stage, thereafter, the restricting pin 8d is pushed by the arm portion 7a and the driving member 8 is rotated counterclockwise in FIG. 2, so that the rotor 6 is rotated counterclockwise until then. The urging force of the torsion coil spring 9 that has been acting so as to rotate toward the end is eliminated. However, at this stage, since the rotational force of the rotor 6 itself has already become very large, the rotor 6 continues to rotate suitably. At that time, since the driving member 8 also starts to rotate counterclockwise, the shutter blade 3 is rotated counterclockwise, and the opening 1a is closed from the substantially opposite side to the shutter blade 4. The shutter blade 5 is rotated together with the shutter blade 4 in the clockwise direction. Then, when the opening 1a is completely closed, immediately after that, the shutter blades 3 and 4 come into contact with the stopper shaft 1d, whereby the rotation of the rotor 6 is stopped. FIG. 3 shows the stop state.

  In this way, when the closing operation of the shutter blades 3, 4, 5 ends, immediately after that, the imaging information photoelectrically converted by the solid-state imaging device is transferred to the storage device. Thereafter, the stator coil is energized in the opposite direction unlike the previous case, so that the rotor 6 is rotated together with the drive member 7 in the clockwise direction in FIG. At this time, the drive member 7 rotates in a direction in which the arm portion 7 a is separated from the restriction pin 8 d of the drive member 8, but a torsion coil spring 9 is hung between the drive member 7 and the drive member 8. Therefore, the drive member 8 rotates together with the drive member 7 in the clockwise direction without leaving the arm portion 7a and the regulation pin 8d. Accordingly, the drive pin 7b of the drive member 7 rotates the shutter blade 4 counterclockwise, and the drive pin 8b of the drive member 8 rotates the shutter blade 3 clockwise and the shutter blade 5 counterclockwise. The opening 1a is opened.

  This opening operation does not change the amount of overlap between the shutter blade 4 and the shutter blade 5 in the initial stage. Therefore, first, after the shutter blades 3 and 5 are completely retracted from the opening 1a, the shutter blade 4 is retracted. Therefore, first, when the shutter blades 3 and 5 are completely retracted from the opening 1a, immediately after that, the shutter blade 3 contacts the stopper shaft 1e and the shutter blade 5 contacts the stopper shaft 1f. As a result, the drive member 8 cannot rotate any further, and thereafter the rotor 6 continues to rotate while the torsion coil spring 9 is tensioned by the drive member 7, and the shutter blade 4 is rotated counterclockwise by the drive pin 7b. Continue to rotate to. Then, when the shutter blade 4 fully opens the opening 1a and immediately contacts the stopper shaft 1f, the rotation of the rotor 6 is stopped. Thereafter, when the energization to the stator coil is cut off, the imaging standby state shown in FIG. 1 is restored.

  In this embodiment, the shutter blades 4 and 5 are rotatably attached to the same blade shaft 1c. However, in the present invention, the shutter blades 4 and 5 are both operated by being attached to different blade shafts. However, the amount of mutual overlap may change. However, as in this embodiment, it is advantageous to make the main plate 1 smaller by attaching it to the same blade shaft 1c. In the present embodiment, of the two blades rotating in the opposite directions, only one blade is divided into two blades, shutter blades 4 and 5, for a total of three. It is also possible to divide the blades 3 into two and make a total of four.

  Further, in the case of the present embodiment, the driving member 8 has its annular portion fitted to the rotor 6, but the present invention is not limited to such a configuration, and the rotation of the driving member 8. As long as the shaft and the rotation axis of the rotor 6 coincide with each other, for example, the base side of the shaft 1g of this embodiment may be thickened and the drive member 8 may be attached thereto. Furthermore, in the case of the present embodiment, the torsion coil spring 9 is wound around the rotor 6, but the present invention is not limited to such a configuration, and a part of the ground plane 1 or the ground plane 1 You may make it wind around the fixing member attached integrally.

  Next, Example 2 will be described. In the first embodiment, the torsion coil spring 9 is provided as means for biasing the drive members 7 and 8 to rotate in opposite directions. The present embodiment is an example in which another urging means is provided in place of the torsion coil spring 9. Therefore, since the configuration other than the torsion coil spring 9 is the same as that of the first embodiment, description of the configuration thereof is omitted. Further, since the operation of the present embodiment is performed in accordance with the first embodiment, the description of the operation is also omitted. Furthermore, in the description of the first embodiment, everything described except for the configuration of the torsion coil spring 9 also applies to the present embodiment.

  FIG. 6 is a diagram showing the present embodiment so as to be easily compared with FIG. 5 used for explaining the first embodiment. The rotor 16 of the present embodiment has the same shape as the rotor 6 of the first embodiment. Similarly to the driving member 7 of the first embodiment, the driving member 17 of the present embodiment is integrally formed with the rotor 16 of a synthetic resin material, and has a driving pin at the distal end portion of the arm portion 17a extending in the radial direction. The drive pin 17b is not made of a synthetic resin, but is made of a permanent magnet that is magnetized in two radial directions, and the center line of the arm portion 17a is used as a boundary line of the magnetic pole. Yes. And the spring hook pin is not standingly arranged in the front-end | tip part of the arm part 17a.

  Further, the drive member 18 of the present embodiment is made of synthetic resin, like the drive member 8 of the first embodiment, and a drive pin 18b is erected at the distal end portion of the arm portion 18a that extends in the radial direction. Although the restriction pin 18c is erected on the portion, the drive pin 18b is not made of synthetic resin but is made of a permanent magnet that is magnetized in two radial directions, and the center line of the arm portion 18a is a magnetic pole. The boundary line. As shown in the figure, the north pole of the drive pin 18b is opposed to the north pole of the drive pin 17b. Further, a spring hook pin is not erected at the tip of the arm portion 18a.

  As can be seen from this configuration, the biasing means in this embodiment is a permanent magnet having two poles each configured as two drive pins 17b and 18b, and arranged so that the same magnetic poles are opposed to each other. It is. For this reason, the two drive members 17 and 18 are given a biasing force that rotates them in opposite directions. Accordingly, it is needless to say that the same function as that of the torsion coil spring 9 of the first embodiment can be achieved, and thus detailed description thereof is omitted. Thus, the urging means of the present invention applies a torsion coil spring between the two drive members, makes the drive pins of the two drive members permanent magnets, and compresses between the arms of the two drive members. There are various means such as interposing a spring.

  The electromagnetic actuator in each of the above embodiments has been described on the assumption that the configuration described in FIGS. 6 and 7 of Patent Document 1 is substantially the same as described above. The present invention is not limited to the one using such an electromagnetic actuator, and can be applied to one using the electromagnetic actuator described in FIGS. 1 and 2 of Patent Document 1, for example. Also, as this type of electromagnetic actuator, it is known that the drive members 7 and 17 are made of permanent magnets together with the rotors 6 and 16. However, the present invention is also applicable to those configured as described above. Applied.

It is the top view of Example 1 which showed the imaging | photography standby state. It is the top view of Example 1 which showed the state in the middle of the closing operation | movement of a shutter blade | wing. It is the top view of Example 1 which showed the completion | finish state of the closing operation | movement of a shutter blade | wing. In Example 1, it is a figure for demonstrating the attachment structure of the two drive means with respect to a rotor. FIG. 5 is a diagram for explaining a relative positional relationship between two driving units during operation of the first embodiment. FIG. 10 is a diagram for explaining a relative positional relationship between two driving units during operation of the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ground plate 1a, 2a Opening part 1b, 1c Blade shaft 1d, 1e, 1f Stopper shaft 1g Shaft 2 Cover plate 2b, 3b, 5b Hole 3, 4, 5 Shutter blade 3a, 4a, 5a Long hole 6,16 Rotor 7 , 8, 17, 18 Drive member 7a, 8a, 17a, 18a Arm 7b, 8b, 17b, 18b Drive pin 7c, 8c Spring hook pin 8d, 18c Restriction pin 9 Torsion coil spring

Claims (8)

  A ground plane having an opening for the photographing optical path, a rotor having a permanent magnet and reciprocatingly rotated in accordance with the energization direction to the stator coil, and an approximate diameter of the rotor integrated with the rotor A first drive means having a first drive pin at a tip end extending in the direction, and the rotor is disposed separately from the rotor and rotatable about the rotation axis of the rotor. A second driving means having a second driving pin at a tip end portion extending in a substantially radial direction of the child, and the first driving means and the second driving means are attached so as to rotate in the opposite directions. An energizing means, a restricting means for restricting the relative angle between the first driving means and the second driving means so as not to exceed a predetermined angle by the energizing force of the energizing means, and the base plate And the first drive means is rotated. A first blade that is rotated by the first drive pin and a second drive pin that is rotatably attached to the main plate and the second drive means rotates in the same direction as the first drive means. The second blade is rotated in a direction opposite to the first blade, and is rotatably attached to the base plate, and the second driving means rotates in the same direction as the first driving means. A third blade that is simultaneously rotated in a direction opposite to the second blade by two drive pins, and when the opening is closed, a relative angle between the first drive device and the second drive device. A shutter device for a digital camera, wherein only the first driving means rotates until the angle reaches the predetermined angle.   The second blade is rotatably attached to the ground plate at a position different from the first blade, and the third blade is rotatable to the same position as the first blade with respect to the ground plate. The shutter device for a digital camera according to claim 1, wherein the shutter device is attached to the camera.   The fourth plate is rotatably attached to the base plate at the same position as the second blade, and is simultaneously rotated in the direction opposite to the first blade by the first drive pin when the first driving means rotates. The shutter device for a digital camera according to claim 1, further comprising a blade.   The shutter device for a digital camera according to any one of claims 1 to 3, wherein the second driving means is rotatably attached to the rotor.   The biasing means is a torsion coil spring, wherein one arm portion is hooked on the first driving means and the other arm portion is hooked on the second driving means. The shutter device for a digital camera according to any one of 1 to 4.   The shutter device for a digital camera according to claim 5, wherein the coil portion of the torsion coil spring is wound around the rotor.   The first drive pin and the second drive pin are made of permanent magnets and are magnetized so that their opposing surfaces have the same polarity in order to constitute the biasing means. The shutter device for a digital camera according to any one of claims 1 to 4.   8. The shutter device for a digital camera according to claim 1, wherein the first driving means is made of a permanent magnet together with the rotor.

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