JPH1096975A - Shutter device and optical instrument with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shutter device capable of executing consecutive exposure as fast as possible and holding light shielding members in an initial stage state, without futile power consumption. SOLUTION: The shutter device having first and second light shielding members 5 and 7 moved respectively between an opening position for opening a shutter aperture 1a and a closing position for closing the shutter aperture, is provided with a control means for executing outgoing direction opening/ closing control for moving the first light shielding member 5 from the closing position to the opening position and then, the second light shielding member 7 from the opening position to the closing position and ingoing direction opening/closing control for returning the second light shielding member 7 from the closing position to the opening position and then, the first light shielding member 5 from the opening position to the closing position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter device for opening and closing a shutter opening with two light blocking members, for example, a focal plane shutter device.

[0002]

2. Description of the Related Art As a focal plane shutter device of a camera, there is a type in which a front curtain (light shielding member) and a rear curtain (light shielding member) are driven by using a spring force. In a shutter device of this type, first, a spring is set to a charged state having potential energy by a DC motor or the like, and the charged state is held by a shutter curtain holding mechanism using a cam or the like. At the time of photographing, the hold by the shutter curtain holding mechanism is switched to the hold by an electromagnet, and the front curtain and the rear curtain are driven by turning off the power to the electromagnet.

The exposure operation of such a shutter device is as follows.
It is controlled according to the flowchart shown in FIG. First,
When the main switch of the camera (not shown) is turned on, the first curtain is in the closed position for closing the shutter opening, and the second curtain is held in the charged state in the initial state of being in the open position for opening the shutter opening (step S101). When it is determined that the release switch (not shown) has been turned on (step S102), the front curtain is released and moved to the open position to perform exposure (step S103). If it is determined that a predetermined time (determined by the set shutter time, etc.) has elapsed after the release of the front curtain (step S
104), the trailing curtain is released and moved to the closed position, and the exposure ends. After the exposure is completed, step S101
To return to the initial state and charge the first curtain again, and then wait for the release switch to be turned on.

[0004]

However, in the control of the shutter device as described above, it is necessary to return the front curtain and the rear curtain to the initial state after the end of one exposure in preparation for the next exposure. It takes a long time before exposure can be performed. In addition, in the case where the DC motor is used for charging the spring, the charging itself takes a long time. For this reason, there is a problem that continuous photographing cannot be performed sufficiently quickly with a camera provided with this shutter device.

In the shutter device, since the electromagnet is energized and held in a charged state, if the hold time is long, the power of the camera may be wasted.

Accordingly, an object of the present invention is to provide a shutter device capable of performing continuous exposure as fast as possible.

It is another object of the present invention to provide a shutter device capable of holding a light shielding member in an initial state (a state corresponding to a charged state) without wasting power.

[0008]

According to a first aspect of the present invention, a first light-shielding member which moves between an open position for opening a shutter opening and a closed position for closing the shutter opening is provided. In the shutter device having the second light-blocking member, after the first light-blocking member is moved from the closed position to the open position (for example, after a first predetermined time has elapsed after returning the first light-blocking member), the second light-blocking member is moved to the second position. The forward opening / closing control for moving from the open position to the closed position, and after returning the second light blocking member from the closed position to the open position (for example, after a lapse of a second predetermined time after returning the second light blocking member), the first Control means is provided for performing opening / closing control for returning the light blocking member from the open position to the closed position.

In other words, the exposure can be performed by moving the light shielding member in the forward direction and moving in the backward direction (return), so that the light shielding member is returned to the initial position after one exposure (forward direction exposure). In this case, the next exposure (backward exposure) can be performed immediately, thereby enabling continuous exposure at a higher speed than a conventional shutter device in which the light-shielding member is returned to the initial position for each exposure.

The first and second predetermined times may be differently set according to a set shutter time, a difference in characteristics between a forward direction and a backward direction of a driving mechanism of a light shielding member, or the like, or may be equal. May be set.

In the second invention of the present application, the first and second light shielding members are configured to be opened and closed by a magnetic force generated by an electromagnetic driving means, and are conventionally provided for driving the light shielding members. The spring and the charging operation of the spring are not required.

In this case, each light shielding member is held at at least one of the closed position and the open position by a magnetic force generated in the electromagnetic driving means when the electromagnetic driving means is in a non-energized state. In such a configuration, it is desirable to suppress power consumption during holding.

When the electromagnetic driving means has a rotor made of a permanent magnet and the direction of rotation of the rotor is switched in accordance with the direction of energization, each of the electromagnetic driving means has It is desirable that the amount of energization in the direction be the amount of energization that causes one rotation position (magnetically stable point) at which the rotor is held by the magnetic force during one rotation of the rotor.
That is, it is desirable that only one magnetic stable point is generated for each energizing direction, the rotation angle between the magnetic stable points is increased, and the operable angle of the rotor is increased as much as possible.

According to the third aspect of the present invention, by providing the above-described shutter device, it is possible to perform continuous photographing at a higher speed than before and realize an optical device such as a camera which consumes less power. .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows a main part of a two-blade focal plane shutter device according to a first embodiment of the present invention. The shutter device includes a shutter driving mechanism described below, a mount 103 disposed in front of the shutter driving mechanism in the optical axis (axis A) direction (upper side in the drawing), and for attaching and detaching an interchangeable lens (not shown). It is arranged behind the shutter drive mechanism in the optical axis direction, and is constituted by an image pickup means 104 for taking an image through the shutter opening 1a.

The shutter driving mechanism has a main plate 1. Reference numeral 1a denotes a shutter opening formed on the base plate 1 and opened in the optical axis direction. Reference numerals 5 and 7 denote a first light-shielding member and a second light-shielding member for opening and closing the shutter opening 1a in accordance with an operation sequence described later.

Reference numeral 8 denotes a main lever rotatably connected to the first light shielding member 5, and has a fitting hole 8a on the base end side. 9
Is an auxiliary lever that is rotatably connected to the first light shielding member 5 and forms a parallel link together with the main lever 8 and moves the first light shielding member 5 in parallel. The auxiliary lever has a fitting hole 9a on the base end side.

Reference numeral 10 denotes a main lever which is rotated by the second light-shielding member 7, and has a fitting hole 10a on the base end side. 1
Reference numeral 1 denotes a main lever 1 which is rotatably connected to a second light blocking member 7.
0 is a parallel link, and is an auxiliary lever for moving the second light shielding member 7 in parallel.
Having.

Reference numerals 12 and 13 denote a pair of shaft portions formed on the base plate 1, and fitting holes 8a and 9a of the main lever 8 and the auxiliary lever 9 are rotatably fitted to these shaft portions 12 and 13. I do. Reference numerals 14 and 15 denote a pair of shaft portions formed on the base plate 1, and fitting holes 10a and 11a of the main lever 10 and the auxiliary lever 11 are rotatably fitted to these shaft portions 14 and 15. . Each of the shafts 12 to 15 is formed in a concentric stepped shape, and the height of the steps of the shafts 12 and 13 is adjusted to the height of the shafts 14 and 1.
5 is lower in the optical axis direction than the height of the step portion. For this reason, the first light shielding member 5 attached around the upper steps of the shafts 12 and 13 via the main lever 8 and the auxiliary lever 9 is provided.
A second light-blocking member 7 attached via a main lever 10 and an auxiliary lever 11 around upper steps of the shafts 14 and 15.
Are held apart from each other in the optical axis direction.

In addition, drive fitting holes 8b and 10b are formed in the intermediate portions of the main levers 8 and 10, respectively. Further, arcuate guide grooves 2 and 3 are formed in a portion of the base plate 1 between the shafts 12 and 14 and the shutter opening 1a.

Reference numerals 20 and 30 denote electromagnetic actuators for driving the first light-shielding member and the second light-shielding member, respectively. These actuators 20 and 30 include yokes 25 and 35 formed in a substantially U-shape, coils 27 and 37 attached to the yokes 25 and 35, and rotors 24 and 3 made of permanent magnets.
4 and rotating shafts 21 and 31 joined to the rotors 24 and 34 so as to be integrally rotatable.

As the magnets 24 and 34, a rare earth plastic magnet or the like that is lightweight, has a large maximum energy product, and can be manufactured with high accuracy is suitable. As shown in detail in FIG. 4, the rotor 24 (same for the magnet 34) is magnetized in the direction of the arrow 47 in the figure. Note that, in FIG.
Reference numeral 51 denotes a terminal of the coil 27. Also, the yokes 25, 3
For 5, a material having high magnetic permeability, for example, iron or the like is suitable.
Here, FIG. 8 shows a drive circuit of each of the actuators 20 and 30. FIG. 8A shows a drive circuit of the actuator 20, and FIG. 8B shows a drive circuit of the actuator 30. In these figures, V is a power supply, G is a ground, B
1, B2, D1 and D2 are control terminals, and Tr1 to Tr4 are transistors.

In FIG. 8A, when the terminal B1 is on and the terminal B2 is off, a current flows in the coil 27 of the actuator 20 via the transistors Tr1 and Tr2 in the direction of the arrow in the figure. When the terminal B1 is off and the terminal B2 is on, a current flows through the coil 27 of the actuator 20 via the transistors Tr3 and Tr4 in the direction opposite to the arrow in the drawing. Therefore, the rotation direction of the actuator 20 can be controlled by the on / off control of the terminals B1 and B2.

On the other hand, in FIG. 8B, when the terminal D1 is on and the terminal D2 is off, the transistors Tr1, T2
A current flows through the coil 37 of the actuator 30 in the direction of the arrow in FIG. Terminal D1 is off and terminal D2
Is ON, a current flows in the coil 37 of the actuator 30 through the transistors Tr3 and Tr4 in the direction opposite to the arrow in the figure. Therefore, the rotation direction of the actuator 30 can be controlled by on / off control of the terminals D1 and D2. The control terminals B11, B2, D
The on / off control of D1 and D2 is performed by a system controller (not shown) in the camera.

Further, as shown in FIG.
1 includes arms 21a, 31a extending in the radial direction, respectively.
Are formed, and driving protrusions 21b and 31b projecting in the optical axis direction are formed at the tips of the arm portions 21a and 31a. These driving projections 21b and 31b are
Are fitted movably in the longitudinal direction of the grooves, and are rotatably fitted in the drive fitting holes 8b, 10b of the main levers 8, 10. Therefore, if a current is applied to the coils 27 and 37 of the actuators 20 and 30 by the above-described drive circuit, the rotors 24 and 34 and the rotating shafts 21 and 31 are rotated in a rotation direction according to the direction of the current, and the arm 21a , 31a and levers 8, 9, 1
The first and second light blocking members 5 and 7 can be driven to open and close via 0 and 11.

At this time, the driving projections 21b and 31b abut against the ends of the guide grooves 2 and 3 so that the light shielding members 5 and
7 are defined. That is, the open position of the first light blocking member 5 is defined by the drive protrusion 21b abutting on the front end of the guide groove 2 in FIG. 1 (see FIGS. 2B and 2C), The closed position of the first light blocking member 5 is defined by contacting the end (FIG. 2A).
reference).

The driving projection 31b abuts on the front end of the guide groove 3 on the near side in FIG.
(See FIG. 2 (c)), and the open position of the second light blocking member 7 is defined by contacting the rear end (see FIGS. 2 (a) and 2 (b)). In the present embodiment, the opening angle between both ends of each of the guide grooves 2 and 3 is set to 50 degrees, and the rotor 2 of each of the actuators 20 and 30 is set.
Each of the light shielding members 5, 7 can be moved between the open position and the closed position by rotating the shafts 4, 34 and the rotating shafts 21, 31 by 50 degrees.

Next, the operation sequence of the focal plane shutter device of this embodiment will be described with reference to FIG.
This will be described with reference to the flowchart of FIG. When a main switch (not shown) is turned on in the camera, FIG.
As shown in (a), the first light-blocking member 5 is held in the closed position and the second light-blocking member 7 is held in the initial state in which it is in the open position (step S1). At this time, the shutter opening 1a is
No exposure is performed because it is closed by the light shielding member 5.

Next, when it is determined that the release switch (not shown) has been turned on (step S2), FIG.
As shown in (b), only the first light blocking member 5 is released and moved to the open position, and the shutter opening 1a is opened to perform exposure (step S4). At the same time, the timer is operated, and when it is determined that the first predetermined time has elapsed (step S4), as shown in FIG. 2C, the second light shielding member 7 is released and moved to the closed position, and the shutter opening 1a is closed. (Step S5).

Here, the first predetermined time is a shutter time set in advance by a photographer or an automatic exposure control device of the camera, or a hold position (open position) of the second light shielding member 7.
Is determined in consideration of the traveling distance from the position to the position where the shutter opening 1a starts to be blocked and the characteristics of the actuator 30 and the shutter driving mechanism.

The first exposure operation is performed by driving the first and second light-shielding members 5 and 7 in the forward direction in this manner. In the present embodiment, after the first exposure is completed, FIG. , That is, with the first light-blocking member 5 at the open position and the second light-blocking member 7 at the closed position (step S6).

Next, when it is determined that the second ON operation of the release switch has been performed (step S7), FIG.
As shown in (b), only the second light blocking member 7 is released and moved to the open position, and the shutter opening 1a is opened to perform exposure (step S8). At the same time, the timer is operated, and when it is determined that the second predetermined time has elapsed (step S9), the first light shielding member 5 is released and moved to the closed position as shown in FIG. 2A, and the shutter opening 1a is closed. (Step S10).

The second predetermined time is, similarly to the first predetermined time, a shutter time set in advance by a photographer or an automatic exposure control device of the camera, or a hold position (open position) of the first light shielding member 5. ) Is determined in consideration of the travel distance from the position to start blocking the shutter opening 1a and the characteristics of the actuator 20 and the shutter driving mechanism.

In this way, the first and second light shielding members 5, 7 are driven in the backward direction to perform the second exposure operation, and the flow ends. In the present embodiment, the first and second light shielding members 5 and 7 are not returned to the initial positions after the end of the first exposure, and when the release operation is performed next, the state at the end of the first exposure is changed. The second exposure is performed by returning to the initial state. For this reason, the time required until the next exposure is shorter than that of the conventional shutter device in which the light shielding member is returned to the initial state each time the exposure is completed (the charging operation of the light shielding member is required), and the continuous shooting can be performed at high speed. It can be carried out.

After completion of the second exposure, the third, fourth, fifth, etc. exposure can be performed by repeating the flow of FIG.

By the way, in the shutter device of the present embodiment, the light shielding members 5, 7 are smoothly opened and closed by utilizing the characteristics of the magnetic circuits formed in the actuators 20, 30. This will be described below in detail with reference to FIGS. 5, 6, and 7. Since the actuators 20 and 30 have the same configuration, only the actuator 20 and the first light shielding member 5 driven by the actuator 20 will be described here.

FIG. 5 shows the coil 2 of the actuator 20.
Reference numeral 7 denotes a non-energized state, and shows a state of the magnetic lines of force in the magnetic circuit when the rotor 24 is at the initial position (position in which the magnetization direction 47 is rightward in the drawing). FIGS. 6 and 7 show changes in the generated torque depending on the rotation angle of the rotor 24 when the coil 27 is in the non-energized state and in the energized state. 6 and 7, the horizontal axis represents the rotor 2
4 shows the rotation angle in the counterclockwise direction in FIG. 4 from the initial position, and the vertical axis shows the magnitude of the generated torque. In addition,
The positive torque increases the rotation angle of the rotor 24 (FIG. 4).
(Medium, counterclockwise) and negative torque is applied to the rotor 2
4 acts in the direction of decreasing the rotation angle (clockwise in FIG. 4).

First, the curve (a) in FIG. 7 shows a change in the generated torque depending on the rotation angle of the rotor 24 when the coil 27 is in the non-energized state, and the curve (b) shows the change in the coil 27 in FIG. The change of the generated torque according to the rotation angle of the rotor 24 in the state where the power supply of 100AT (AT = ampere turn) is performed in the arrow direction of a) is shown. The curve (c) shows a change in the generated torque depending on the rotation angle of the rotor 24 when the coil 27 is energized for 100 AT in the direction opposite to the arrow in FIG. 8A. With the torque curve shown in FIG. 7, when the coil 27 is in the energized state, the rotor 24 moves at an angle (g) on the curve (c).
As shown in the above, as the rotational angle increases, the torque acts toward the magnetically stable point, which is the rotational angle at which the torque acting direction reverses from the positive side to the negative side. Then, at the magnetically stable point, it is held at this position by the torque acting when trying to rotate from this position. Note that when 100 AT is energized (curves (b) and (c)), one magnetically stable point occurs during one rotation of the rotor 24.

On the other hand, the curve (h) in FIG. 6 shows a change in the generated torque depending on the rotation angle of the rotor 24 when the coil 27 is in the non-energized state, and is equal to the curve (a) in FIG. Curve (i) shows a change in generated torque depending on the rotation angle of the rotor 24 in a state where the coil 27 is energized by 50 AT in the direction of the arrow in FIG. 8A, and curve (j) shows 8 in the direction opposite to the arrow in FIG.
The change of the generated torque according to the rotation angle of the rotor 24 in the state where the energization of 0AT is performed is shown. As can be seen from this figure, when 50 AT is energized (curves (i) and (j)), the magnetic stable point is, for example, as shown by the angles (k) and (m) on the curve (j). Two occur during one rotation of the rotor 24.

As described above, when the magnetic circuit is not energized or energized for a low ampere turn of about 50 AT, two magnetic stable points are generated during one rotation of the rotor 24, but about 100 AT. In the state in which the energization of the high ampere turn is performed, only one magnetic stable point is generated during one rotation of the rotor 24. That is,
If a current of a predetermined value or more flows in the present magnetic circuit, a magnetically stable point, that is, a position where the rotor 24 stops rotating can be generated one by one in each energizing direction.

Therefore, the movable angle as an actuator for driving the light shielding member 5, that is, the difference between the magnetically stable point when energizing in the direction of the arrow shown in FIG. 8A and the magnetically stable point when energizing in the opposite direction. The rotation angle between them can be made sufficiently wide (in the present embodiment, 50 degrees or more). Therefore, even in the shutter device of the present embodiment, the coil 27 is energized by 100 AT.

Since the generated torque can be increased by increasing the ampere-turn of the coil, the torque can be easily increased without increasing the size of the rotor 24. Furthermore, since the coil 27 of the actuator 20 is supported by the yoke 25, the rotor 24 has no load due to power supply means such as a power input terminal. Therefore, the rotor 24 can be operated smoothly.

When the coil 27 has a torque curve shown in FIG.
Rotates in a direction away from the magnetically unstable point, which is a rotation angle at which the torque acting direction reverses from the negative side to the positive side as the rotation angle increases, as shown by the angle (f) on the curve (a).

In the shutter device of this embodiment, the rotor 24 is rotated between an angle (d) and an angle (e) sandwiching the angle (f), which is a magnetically unstable point. For this reason, in the range from the rotation angle (d) to the rotation angle (f) where the first light shielding member 5 is located at the closed position, the rotor 24 moves clockwise in FIG. In the range from the rotation angle (f) to the rotation angle (e) at which the first light shielding member 5 is located at the open position, the rotor 24 is rotated counterclockwise in FIG. Biased in the direction. In the shutter device of the present embodiment, the angles (d) to (e) are set to 50 degrees.

The driving projection 21 is driven by the urging force.
By contacting b with the end of the guide groove 2, the first light-blocking member 5 can be held at the open position and the closed position in the non-energized state of the actuator 20 without providing a holding mechanism such as a cam or an electromagnetic magnet. Can be. For this reason, there is no power consumption when the first light blocking member 5 is held, and a shutter device and hence a camera that consumes less power can be realized. In addition, since it is known that the first light shielding member 5 is held at either the open position or the closed position in the non-energized state, a mechanism for detecting the position of the first light shielding member 5 in the non-energized state. Need not be provided.

When the coil 27 is energized for 100 AT in the direction of the arrow in FIG. 8A, the first light shielding member 5 held in the closed position (initial position) in the non-energized state causes the rotor 24 to be curved. By driving in a direction to increase the rotation angle by a torque having a magnitude represented by (b) (a torque on the positive side that is larger than the generated torque on the negative side at the rotation angle (d) in the non-energized state), Driven to the open position.

On the other hand, when the first light-blocking member 5 held at the open position in the non-energized state is energized by 100 AT in the coil 27 in the direction opposite to the arrow in FIG. The drive is driven in a direction to reduce the rotation angle by a torque having a magnitude represented by c) (a negative torque that is larger than a generated torque on the positive side at the rotation angle (e) in the non-energized state). Driven into position.

As described above, in the shutter device of the present embodiment, the first direction is switched by switching the direction of current supply to the coil 27.
The light-shielding member 5 can be driven in a direction of releasing from the initial position (closed position) to the open position (forward direction) and in a direction of returning from the open position to the initial position (return direction). Therefore, the first light blocking member 5 can be opened and closed with a simple mechanism and a simple electric circuit.

Further, since the actuator 20 has torque characteristics substantially symmetrical in the release direction and the return direction from the unstable equilibrium point, the release operation and the return operation of the first light shielding member 5 are performed in substantially the same time. be able to.

Although the operation of the actuator 20 and the first light-blocking member 5 driven by the actuator 20 has been described above, the same applies to the operation of the actuator 30 and the second light-blocking member 7 driven by the actuator.

In this embodiment, the operating angle of the actuator from the open hold end to the closed hold end of the light shielding members 5 and 7 is set to 50 degrees. However, as shown in FIG. If energization is performed, an operation angle larger than 50 degrees is possible.

Further, in the present embodiment, the state in which the first light shielding member 5 is located at the closed position and the second light shielding member 7 is located at the open position is an initial state. Can be applied to a shutter device in which an initial state is a state in which the second light blocking member 7 is located in the open position and the second light blocking member 7 is located in the closed position. In this case, the second light-blocking member 7 corresponds to a first light-blocking member in the claims, and the first light-blocking member 5 corresponds to a second light-blocking member in the claims.

In this embodiment, the case where the present invention is applied to a focal plane shutter has been described. However, the present invention can be applied to other shutter devices.

Further, the present invention can be applied to various types of cameras such as a single-lens reflex camera and a lens shutter camera, and furthermore, optical devices and other devices other than cameras, and furthermore, these cameras and optical devices The present invention can also be applied to a device applied to or another device or an element constituting these devices.

[0055]

As described above, according to the present invention, exposure can be performed by moving the light blocking member in the forward direction and moving in the backward direction (return), so that after one exposure (forward direction exposure), The next exposure (backward exposure) can be performed immediately without returning the light shielding member to the initial position. Therefore, continuous exposure can be performed at a higher speed as compared with a conventional shutter device that returns the light shielding member to the initial position for each exposure.

If the light shielding member is configured to be opened and closed by a magnetic force generated by the electromagnetic driving means,
The spring conventionally provided for driving the light shielding member and the charging operation of the spring can be eliminated.

When the electromagnetic driving means is in a non-energized state, the light shielding member is held at at least one of the closed position and the open position by the magnetic force generated in the electromagnetic driving means. Thus, power consumption during holding can be suppressed.

Further, if the amount of energization of the electromagnetic driving means is set to an amount of energization at which only one magnetic stable point occurs in each energizing direction, the rotation angle between each magnetic stable point is increased. Therefore, the operable angle of the rotor for driving the light shielding member can be increased.

By providing the shutter device as described above, continuous photographing can be performed at a higher speed than before, and an optical device such as a camera which consumes less power can be realized.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a main part configuration of a focal plane shutter device according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory view of the focal plane shutter device.

FIG. 3 is an operation flowchart of the focal plane shutter device.

FIG. 4 is a plan view of an electromagnetic actuator used in the focal plane shutter device.

FIG. 5 is a magnetic force diagram of the electromagnetic actuator.

FIG. 6 shows the state when no power is supplied to the electromagnetic actuator and
It is a graph which shows the torque curve at the time of 0 ampere turn-on electricity supply.

FIG. 7 shows a state where the electromagnetic actuator is not energized and
It is a graph which shows the torque curve at the time of energization of 00 ampere turn.

FIG. 8 is a drive circuit diagram of the electromagnetic actuator.

FIG. 9 is an operation flowchart of a conventional focal plane shutter device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 shutter base plate 1 a shutter opening 5 first light shielding member 7 second light shielding member 20, 30 electromagnetic actuator 24, 34 rotor 27, 37 coil 103 mount 104 imaging means

Claims (6)

[Claims] 1. A shutter device having a first light-shielding member and a second light-shielding member that move between an open position for opening a shutter opening and a closed position for closing the shutter opening, respectively, wherein the first light-shielding member is moved to the closed position. After moving from the open position to the closed position after moving the second light shielding member from the open position to the closed position, and after returning the second light shield member from the closed position to the open position, A shutter device comprising a control unit for performing a backward opening / closing control for returning the first light blocking member from the open position to the closed position. 2. The control means moves the second light-shielding member after a first predetermined time has elapsed after moving the first light-shielding member in the forward opening / closing control, and controls the second light-shielding member in the backward opening / closing control. 2. The shutter device according to claim 1, wherein the first light shielding member is returned after a second predetermined time has elapsed since the light shielding member was returned. 3. 3. The shutter device according to claim 1, wherein the first and second light blocking members are driven to open and close by a magnetic force generated by an electromagnetic driving unit. 4. The light shielding member is held at at least one of the closed position and the open position by a magnetic force generated in the electromagnetic driving means when the electromagnetic driving means is in a non-energized state. The shutter device according to claim 3, wherein: 5. The electromagnetic driving means has a rotor made of a permanent magnet, and the rotation direction of the rotor is switched according to the energizing direction. 5. The shutter device according to claim 3, wherein the amount of energization in the direction is an amount of energization that causes one rotation position of the rotor to be held by a magnetic force during one rotation of the rotor. . 6. An optical apparatus comprising the shutter device according to claim 1.