JP2001296582A - Focal plane shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a light shielding performance while attaining the miniaturization of a focal plane shutter and simplifying the structure of the shutter. SOLUTION: The focal plane shutter is provided with a substrate 10 with an aperture part 10a, a 1st blade group 20 and a 2nd blade group 30 arranged on the rear side of the substrate so as to open/close the aperture, 1st and 2nd blade driving levers 40 and 50 arranged on the front side of the substrate so as to move the blade groups back and forth, and through-holes 10c and 10d formed in the substrate so as to allow the movement of connecting pins 42 and 52 for the driving levers connected to the 1st blade group and the 2nd blade group, and the focal plane shutter is provided with a movable shielding plate 70 capable of shielding the through-hole 10c which is adjacent to a notched hole 10b for storing the supporting shaft of a reflection mirror, and the plate 70 is driven by a set lever 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focal plane shutter for a camera having a group of shutter blades for opening and closing an opening formed in a substrate so as to allow subject light to pass therethrough, and more particularly, to a focal plane shutter disposed on the back side of the substrate. The present invention relates to a focal plane shutter for a camera having a through-hole allowing connection between a shutter blade group and a driving lever arranged on the front side of a substrate.

[0002]

2. Description of the Related Art As shown in FIGS. 6 and 7, a conventional focal plane shutter mounted on a camera has a substrate (base plate) 1 having an opening 1a for allowing subject light to pass therethrough.
A front blade group 2 and a rear blade group 3 forming a shutter blade group are disposed on the back side of the substrate 1. On the other hand, a driving lever for driving the front blade group 2 and the rear blade group 3 is provided on the front left side of the substrate 1. And the like, and an exposure operation is performed on a photographic film disposed behind the rear surface of the substrate 1.

In order to permit the movement of the connecting pins 4 and 5 of the drive lever connected to a part of the front blade group 2 and the rear blade group 3, the substrate 1 has a moving locus of the connecting pins 4 and 5. A long hole 1b on the front blade side and a long hole 1c on the rear blade side as through holes are respectively provided along. Further, the substrate 1 is provided with a cutout hole 1d for accommodating a part of the support shaft 6a that rotatably supports the reflection mirror 6 in an upper edge region of the opening 1a.

In this focal plane shutter, for example, when the charge of the shutter is set, as shown in FIG. 7, the front blade group 2 expands downward and is located at the closed position, and the rear blade group 2 3 are located at the open position where they overlap with each other, so that the slot 1b on the leading blade side is opened to allow light to enter the rear side of the substrate 1, that is, the photographic film side. In the vicinity,
Since there is also a cutout hole 1d, light can be more easily entered by reflection or the like. Therefore, this front blade side slot 1
b to prevent light from entering the back side of the substrate 1 directly or through the gap of the cutout hole 1d, and to secure light-shielding properties against the photographic film.
a and a light-shielding wall plate surrounding the reflection mirror, or a box-like light-shielding cover 7 surrounding the area where the drive lever and the like are arranged as shown in FIG. The long holes 1b, 1c and the like are entirely covered.

[0005]

However, in the above-described configuration in which the light shielding cover 7 and the like are provided, a space for disposing the light shielding cover 7 and the like is required, and the light shielding cover 7 and the like are dedicated. Since they are separately formed as a product by molding or the like, the size of the device, the complexity of the device, the cost of the device are increased, and the size of the camera body on which the focal plane shutter is mounted is also increased. There was a problem. The present invention has been made in view of the above-mentioned problems, and has as its object to reduce the size and cost of the device, simplify the structure, and improve the functional reliability. It is an object of the present invention to provide a focal plane shutter which can improve the light shielding property of the shutter while ensuring the above, and can contribute to downsizing of the camera body.

[0006]

SUMMARY OF THE INVENTION A focal plane shutter according to the present invention is movable between a substrate having an opening through which light passes, and a closed position covering the opening and an open position opening the opening. A shutter blade group arranged on the back side of the substrate, a drive lever arranged on the front side of the substrate to drive the shutter blade group to reciprocate, a part of the drive lever and a part of the shutter blade group And a through-hole formed in the substrate to allow movement of the connecting portion that connects to the substrate, and a focal plane shutter that is movable relative to the substrate so as to shield and open the through-hole. A movable shielding plate, and driving means for driving the movable shielding plate. According to this configuration, the movable shielding plate is moved above the through-hole by the driving means operating at a desired timing, and shields the through-hole communicating from the front side to the back side of the substrate. As a result, light is shielded from the photographic film located behind the rear surface of the substrate. Also, immediately before the exposure operation,
The movable shield plate is retracted from the through hole, and enables movement of the drive lever and the like during the exposure operation. Furthermore, since the movable shield plate is independent of the shutter blade group, the shutter blade group performs opening and closing operations quickly and accurately without being affected by the responsiveness of its operation.

In the above configuration, it is possible to adopt a configuration in which the movable shielding plate is driven so as to shield the through hole when the charge of the shutter is set. According to this configuration, in a state where the charge of the shutter is set, the movable shielding plate is moved by the driving unit to shield the through hole of the substrate. As a result, light is shielded from the photographic film located behind the rear surface of the substrate. In particular, when the camera is in the standby state for shooting or when the power of the camera is turned off, the shutter charge is always kept in the set state, and the through hole should be kept in the state covered by the shielding part. , And the shading of the photographic film is efficiently performed.

In the above structure, a set lever rotatably arranged on the front side of the substrate is provided so that the set lever can be set and released by engaging with the drive lever, and the set lever is movable. A configuration that also serves as a driving unit of the shielding plate can be adopted. According to this configuration, the set lever operates the drive lever that drives the shutter blade group to open and close, and also operates the movable shield plate. Therefore, a dedicated component for driving the movable shielding plate becomes unnecessary, and the structure is simplified. Further, the operation timing of the shutter blade group and the movable shielding plate is synchronized with each other via the set lever. This allows
At a necessary timing according to the position of the shutter blade group, the operation of shielding and opening the movable shielding plate is reliably performed.

In the above configuration, it is possible to adopt a configuration in which the movable lever is driven so as to open the through hole when the set lever is moved to a position where the charge of the shutter can be released. According to this configuration, when the set lever moves to a position where the charge of the shutter can be released by a release operation or the like, the movable shielding plate opens the through hole, that is, retracts to a position away from the through hole. The drive lever located in the region of the through hole that has been moved can be moved, and the shutter blade group is caused to travel to perform the exposure operation.

In the above configuration, the shutter blade group includes a front blade group and a rear blade group, and the driving lever includes a front blade driving lever for driving the front blade group and a rear blade driving lever for driving the rear blade group. The through hole is a through hole for the front blade that allows movement of a connecting portion that connects a part of the front blade drive lever and a part of the front blade group, and a part of the rear blade drive lever and the rear blade group. The movable shield plate is configured so as to be able to shield and open at least the front blade through hole, which is configured to include a rear blade through hole that allows movement of a connecting portion that connects a part thereof. be able to. According to this configuration, in a state where the charge of the shutter is set, for example, when the leading blade group is located at the closed position closing the opening and the trailing blade group is located at the opening position opening the opening,
The through hole for the front blade is opened, and light can enter the back side of the substrate. Therefore, the movable shielding plate is moved so as to shield the through-hole for the front blade, so that light entering through the through-hole for the front blade is blocked, and light is blocked against the photographic film located at the rear rear of the substrate. In particular, when the through hole for the front blade is close to the notch hole for accommodating the support shaft of the reflection mirror (for example, the finder is located above the camera, that is, the notch hole is located above, and the shutter blade group is located below the camera. When the exposure operation is performed by traveling upward from above, or when the finder is below the camera, that is, when the notch hole is below, and the shutter blade group runs downward from above the camera to perform the exposure operation. By shielding the through hole for the front blade with the movable shielding plate, it is possible to prevent light or the like that has entered through the cutout hole from further entering the back side of the substrate.

In the above configuration, it is possible to adopt a configuration in which the reflectance of the movable shielding plate is smaller than the reflectance of the portion of the shutter blade group that opens and closes the opening. According to this configuration, light or the like that enters through a gap between the movable shielding plate and the substrate, or through a gap such as a notch hole for mounting a reflection mirror formed in the upper edge region of the opening,
It can be prevented from being reflected by the movable shielding plate and the like toward the rear side of the substrate, that is, toward the photographic film as much as possible. As a result, light shielding of the photographic film is performed more reliably.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 5
1 shows an embodiment of a focal plane shutter according to the present invention. FIG. 1 is a plan view showing a substrate provided with an opening through which subject light passes, and FIG. 2 is a movable shielding plate and a driving lever. FIG. 3 is a plan view showing the state of a group of shutter blades before the shutter charge is set, and FIG. 4 is a plan view showing the state of the group of shutter blades before the charge of the shutter is set. FIG. 5 is a plan view showing a state of a shutter blade group and the like immediately after a shutter release operation is performed.

The focal plane shutter according to this embodiment has an opening 10 through which light (subject light) passes.
a front blade group as a shutter blade group movably arranged on the rear side of the ground plate 10 as a substrate having the base plate 10 and a closed position covering the opening 10a and an open position opening the opening 10a. 20 and a rear blade group 30; a front blade driving lever 40 and a rear blade driving lever 50 arranged on the front side of the main plate 10 to drive the front blade group 20 and the rear blade group 30 to reciprocate; 60
And the like, and a movable shielding plate 70 capable of shielding the through-hole of the substrate 10 and the like.

As shown in FIG. 1, a base plate 10 as a substrate has an outer contour formed in a substantially rectangular shape, and its surface is painted in black or the like. A rectangular opening 10a is provided in the central region.
A notch hole 10b for accommodating the support shaft of the reflection mirror is provided in the upper edge region of Oa. Further, the opening 10
The connecting pin 4 of the leading blade drive lever 40 is located in the left area of FIG.
2, a front blade through-hole 10c of an arc-shaped long hole, a rear blade through-hole 10d of an arc-shaped long hole through which a connecting pin 52 of the rear blade drive lever 50 passes.

Behind the base plate 10, an intermediate plate 11 is arranged at a predetermined interval. This intermediate plate 11
As shown by a dotted line in FIG. 1, the outer contour is substantially rectangular and formed so as to escape through holes 10c for the leading blade and through holes 10d for the trailing blade of the base plate 10, and the surface of the base plate 10 It is painted in black color etc. A substantially rectangular opening 11a is provided in the central region.

Behind the intermediate plate 11, a cover plate 12 is arranged at a predetermined interval. The outer contour of the cover plate 12 is formed in a substantially rectangular shape similar to that of the base plate 10. An opening 12a slightly larger than the opening 10a of the main plate 10 is provided in the central region.
Is provided. In the left region of the opening 12a, a through hole 12c for the front blade which forms a similar circular arc-shaped hole is provided at a position overlapping with the through hole 10c for the front blade of the base plate 10, and the rear blade of the base plate 10 is provided. A rear-blade through-hole 12d, which forms a similar arc-shaped long hole, is provided at a position overlapping with the through-hole 10d.

The back side of the main plate 10, that is, the main plate 1
In a space between 0 and the intermediate plate 11, a front blade group 20, which is a part of the shutter blade group, is disposed, and is deployed downward to cover the opening 10a (11a, 12a);
The opening 10a (11a, 12a) overlaps above the opening 10a (11a, 12a) and is reciprocally movable between an opening position where the opening 10a (11a, 12a) is opened. On the back side of the base plate 10, that is, in the space between the intermediate plate 11 and the cover plate 12, a rear blade group 30, which is a part of the shutter blade group, is arranged. 11a, 12
a) and the openings 10a (11a, 12a).
a) The opening 10a (11a, 1
2a) is reciprocally movable between an open position and an open position.

As shown in FIG. 4, the front blade group 20
Four front blades, that is, a first front blade 21 and a second front blade 2
2, a third front blade 23, a fourth front blade 24, and two link members 25, 26 for rotatably linking these front blades.
And the like. One end of the link member 25 is rotatably connected to a support shaft 13 provided on the main plate 10, and one end of the link member 26 is rotatable about a pivot 14 provided on the main plate 10. Are linked. Also,
A long hole-shaped connection hole 25a is formed in a part of the link member 25, and the connection pin 42 of the leading blade drive lever 40 is fitted into the connection hole 25a. Here, the trajectory (radius of the trajectory) of the connection hole 25a when the link member 25 rotates about the support shaft 13 is
It is formed so as to coincide with the extending direction (radius of curvature of the circular arc) of the through hole 10 c for the leading blade. In addition, the front blade group 20
The portion that opens and closes the opening 10a is painted gray or the like for strobe light control or the like.

As shown in FIG. 3, the rear blade group 30 includes four rear blades, that is, a first rear blade 31, a second rear blade 32, a third rear blade 33, a fourth rear blade 34, and a rear blade. It is composed of two link members 35 and 36 that link the blades rotatably. One end of the link member 35 is rotatably connected to a support shaft 15 provided on the main plate 10,
One end of the link member 36 is rotatably connected to a pivot 16 provided on the main plate 10. A long hole-shaped connection hole 35a is formed in a part of the link member 35, and the rear blade drive lever 5 is connected to the connection hole 35b.
The zero connection pin 52 is fitted. Here, the trajectory (radius of the trajectory) of the connection hole 35a when the link member 35 rotates about the support shaft 15 is set to coincide with the extension direction (radius of curvature of the arc) of the through hole 10d for the rear blade. Is formed. In the front blade 20 or the rear blade group 30, the portion corresponding to the opening 10a on the subject side may be painted in a gray color other than black for strobe light control or the like.

As shown in FIG. 2, a driving mechanism for driving the front blade group 20 and the rear blade group 30 is rotatably disposed in a region above the left side of the opening 10a on the front side of the main plate 10 and is rotatable. A leading blade drive lever 40 for driving the blade group 20;
The rear blade drive lever 5 that is rotatably disposed in a region below the front blade drive lever 40 and drives the rear blade group 30
0, these front blade drive lever 40 and rear blade drive lever 5
0, a set lever 60 rotatably disposed in a region between 0 and engageable with the front blade drive lever 40 and the rear blade drive lever 50, and a charge that engages with the set lever 60 to control the charge of the shutter. It is constituted by a lever (not shown), a drive motor (not shown) for applying a driving force to the charge lever, and the like.

The above-mentioned set lever 60 is shown in FIG.
As shown in (b) and (c), a torsion spring (not shown) is disposed on the front side of the main plate 10 so as to be rotatable around the support shaft 17 and is disposed in the region of the support shaft 17. As a result, the projection 61 is urged to rotate clockwise in FIG. 2, and the projection 61 is always engaged with a part (not shown) of the charge lever from above. Further, the set lever 60 is configured as shown in FIG.
As shown in (b) and (c), in addition to the protruding portion 61, a first engaging portion 62 having a curved surface, a second engaging portion 63 also having a curved surface, and projecting rearward from the rear surface side. It is formed integrally with a set pin 64 and a release pin 65 provided.

The leading blade drive lever 40 is shown in FIG.
As shown in (b) and (c), a torsion spring (not shown) is disposed on the front side of the main plate 10 so as to be rotatable around the support shaft 13, and is disposed in the region of the support shaft 13. Thus, it is urged to rotate counterclockwise in FIG. Further, the leading blade drive lever 40 is provided with an engaging portion 41 that can engage with the first engaging portion 62 of the set lever 60.
A connecting pin 4 extending to the rear side (rearward) of the main plate 10 through the through hole 10 c for the front blade and connected to the connection hole 25 a of the front blade group 20 (link member 25) to form a connection portion.
2 (a part of the drive lever), an iron piece 43 attracted to the magnetic force, a mechanism including a spring for reducing the impact force of the iron piece 43, and the like. Here, the trajectory (radius of the trajectory) of the connecting pin 42 when the leading blade driving lever 40 rotates about the support shaft 13 is the leading blade through hole 10c.
Are formed so as to coincide with the extension direction (the radius of curvature of the circular arc).

The rear blade drive lever 50 is shown in FIG.
As shown in (b) and (c), a torsion spring (not shown) is disposed on the front side of the base plate 10 so as to be rotatable around the support shaft 15 and is disposed in the region of the support shaft 15. Thus, it is urged to rotate counterclockwise in FIG. The rear blade drive lever 50 is provided with an engaging portion 51 that can engage with the second engaging portion 63 of the set lever 60.
And a connecting pin 52 extending to the rear side (rear) of the main plate 10 through the rear blade through-hole 10d and connected to the connecting hole 35a of the rear blade group 30 (link member 35) to form a connecting portion.
(Part of drive lever) and iron piece 5 attracted by magnetic force
3. It is formed by a mechanism including a spring for alleviating the impact force at the iron piece 53. Here, the trajectory (radius of the trajectory) of the connecting pin 52 when the rear blade drive lever 50 rotates about the support shaft 15 coincides with the extension direction (the radius of curvature of the circular arc) of the rear blade through-hole 10d. It is formed as follows.

On the front side of the base plate 10 and behind the front blade drive lever 40, a movable shielding plate 70 for shielding the front blade through hole 10c at a predetermined timing is arranged. The movable shielding plate 70 is rotatably disposed around a support shaft 18 provided on the main plate 10 and is wider than the through hole 10c for the front blade along the shape of the through hole 10c for the front blade. , A first engaging portion 72 capable of engaging with the set pin 64 of the set lever 60, a second engaging portion 73 capable of engaging with the release pin 65 of the set lever 60, and the like. It is formed in a thin plate shape.

Therefore, the set pin 64 of the set lever 60 is engaged with the first engagement portion 72 of the movable shielding plate 70,
When the movable shielding plate 70 is rotated clockwise in FIG. 2, as shown in FIG. 2B, the shielding portion 71 shields the through-hole 10 c for the front blade, while the release pin 65 of the set lever 60 is released. Engages with the second engaging portion 73 of the movable shielding plate 70, and rotates the movable shielding plate 70 counterclockwise in FIG. 2, as shown in FIGS. 2 (a) and 2 (c). The shielding portion 71 is evacuated to open the through hole 10c for the leading blade.

As described above, the movable shielding plate 70 is provided with a shielding position for shielding the leading blade through hole 10c and the leading blade through hole 1c.
Open position to retract from 0c and open it (evacuation position)
The front blade through-hole 10c is shielded at a desired operation timing, so that light entering the back side of the substrate 10 from the front blade through-hole 10c is blocked (shielded). In addition, the front blade through hole 10c is opened (retracted from) in a short time immediately before the exposure operation or the like, and the front blade drive lever 40 that drives the front blade group 20 can be moved. be able to. By providing a stopper (not shown) with which a part of the movable shielding plate 70 abuts when the movable shielding plate 70 reaches the retreat position and the shielding position, further movement of the movable shielding plate 70 is provided. Be regulated. Thereby, the movable shielding plate 70 can be positioned with high accuracy at the retreat position and the shielding position.

Further, since the movable shielding plate 70 is formed as a separate member independent of the front blade group 20 and the rear blade group 30, etc., the opening / closing operation (running operation) of the front blade group 20 and the rear blade group 30 is performed. ) Is not affected. Therefore, the opening and closing operation (exposure operation) of the front blade group 20 and the rear blade group 30 is performed quickly and reliably. Further, the movable shielding plate 70 is formed in a thin plate shape and has the leading blade drive lever 4.
Since it is arranged behind the zero, no special arrangement space is required, and as a result, the device can be downsized. Further, the movable shielding plate 70 is formed as a simple member that rotates around the support shaft 18, and drives the leading blade driving lever 40 and the trailing blade driving lever 50 as driving means for driving the same. Set lever 60 for
Is also used, so that the structure can be simplified, the number of parts can be reduced, the cost can be reduced, and the like.

The surface of the movable shielding plate 70 is painted black or the like. In other words, the movable shield plate 70 is painted so that the reflectance thereof is lower than the reflectance of the portion that opens and closes the opening 10a of the front blade group 20 and the rear blade group 30. As described above, by reducing the reflectance of the movable shielding plate 70, the movable shielding plate 70 and the front blade through-hole 10 are formed.
c can be more reliably prevented from being reflected to the back side of the base plate 10 through the gap with the notch hole 1 located in the vicinity.
The light that has entered through 0d can be more reliably prevented from being reflected toward the back side of the main plate 10.

In this embodiment, in order to move the movable shielding plate 70 to the retreat position, the set lever 60 is moved.
, The structure including the release pin 65 and the second engaging portion 73 is adopted, but these are not used, but the support shaft 18 is used.
2, a torsion spring (not shown) for constantly urging the movable shielding plate 70 counterclockwise in FIG. 2 is employed, and the movable shielding plate 70 is moved to the retreat position by the urging force of the torsion spring. You may do so.

The set lever 60, the front blade drive lever 40, and the rear blade drive lever 5 arranged on the front side of the main plate 10
0, a circuit board (not shown) is further arranged on the near side (front side) of the movable shielding plate 70 and the like in parallel with the ground plate 10.
An electromagnet 80 for the leading blade and an electromagnet 90 for the trailing blade are mounted on the back surface of the circuit board. The front blade electromagnet 80 and the rear blade electromagnet 90 are, as shown in FIG.
1 and 91 are wound around electromagnetic coils 82 and 92 and the like. And these electromagnetic coils 82,
When the current 92 is energized, an electromagnetic force is generated, and the front blade electromagnet 80 and the rear blade electromagnet 90 respectively move the iron piece 43 of the front blade drive lever 40 and the iron piece 53 of the rear blade drive lever 50. It is designed to adsorb.

As shown in FIG. 2A, the relationship between the operation of the front blade driving lever 40, the rear blade driving lever 50, the set lever 60, and the movable shielding plate 70 is as follows. When in the release position rotated clockwise by the biasing spring, the leading blade drive lever 40 is rotated counterclockwise by the biasing force of the torsion spring and is in the return position shown in FIG.
Also, the rear blade drive lever 50 is rotated counterclockwise by the urging force of the torsion spring, and is at the return position shown in FIG. Further, the movable shield plate 70 is at the retracted position where the second engagement portion 73 is pushed by the release pin 65 of the set lever 60 and rotated counterclockwise.

In this state, as shown in FIG. 3, the leading blade group 20 is located at the overlapping open position, and the trailing blade group 30 is located at the developed closed position. That is, this corresponds to a state before the charge (energy accumulation) of the shutter is set (or a state after the exposure operation). Further, the movable shielding plate 70 is in a state where the through-hole 10 c for the leading blade is opened as shown in FIGS. 2A and 3.

Subsequently, when the set lever 60 is rotated counterclockwise to reach the set position as shown in FIG. 2B, the first engaging portion 62 is moved to the leading blade drive lever 4.
The second engaging portion 63 engages with the engaging portion 51 of the rear blade drive lever 50. And
The front blade driving lever 40 and the rear blade driving lever 50 are rotated clockwise while resisting the urging force of the torsion spring. Further, the set pin 64 of the set lever 60 is engaged with the first engaging portion 72 of the movable shielding plate 70, and the movable shielding plate 70 is rotated clockwise.

In this state, as shown in FIG. 4, the leading blade group 20 moves downward and is located at the expanded closed position, and the trailing blade group 30 moves downward and is located at the overlapping open position. become. Further, as shown in FIGS. 2B and 4, the movable shielding plate 70 is provided with a through hole 10c for the leading blade.
Will be located at the shielding position where is shielded. That is,
With the shutter charge set, the first blade group 2
0 closes the opening 10a (11a, 12a), and the front blade through hole 1 opened by the movement of the front blade group 20.
The movable shielding plate 70 shields 0c.

Subsequently, the locked state of the set lever 60 at the set position is released by the release operation, and the set lever 60 is rotated clockwise by the biasing force of the torsion spring and returns to the released position. At this time, first, the leading blade electromagnet 80 and the trailing blade electromagnet 90 are respectively energized, and as shown in FIG. 2C, the leading blade electromagnet 80 attracts the iron piece 43 of the leading blade driving lever 40. Then, the electromagnet 90 for the rear blade attracts the iron piece 53 of the rear blade drive lever 50.

Thus, the first engaging portion 62 and the second engaging portion 63 of the set lever 60 are disengaged from the engaging portion 41 of the front blade drive lever 40 and the engaging portion 51 of the rear blade drive lever 50. Also, as shown in FIG. 2C, the front blade drive lever 40 and the rear blade drive lever 50 are held in the state rotated clockwise. Further, while the set pin 64 of the set lever 60 is disengaged from the first engagement portion 72 of the movable shielding plate 70, the release pin 65 of the set lever 60 is
2 is engaged with the second engaging portion 73 of the movable shielding plate 70, and FIG.
As shown in (c), the movable shielding plate 70 is rotated counterclockwise.

In this state, as shown in FIG. 5, the front blade group 20 moves downward and stays at the closed position where it is deployed, and the rear blade group 30 moves downward and stays at the overlapping open position. Will do. Further, the movable shielding plate 70 is located at an open position (a retracted position) where the leading blade through-hole 10c is opened, as shown in FIG. 2C and FIG. That is, the state corresponds to the state where the charge (energy storage) of the shutter is set and the state immediately before the exposure operation, and the front blade group 20 moves the opening 10a (11a, 1a).
2a) is closed, and the movable shielding plate 70 is
c is released again, and the state in which the leading blade drive lever 40 can be rotated counterclockwise is enabled.

Next, the operation when the focal plane shutter according to the above embodiment is mounted on a camera will be described.
This will be described with reference to FIGS. 3 to 5 are shown as perspective views in which, for convenience of description, what should be dotted lines are represented by solid lines. First, a state in which the shutter charge is not set (the shutter blade group 20,
3), the set lever 60, the front blade drive lever 40, and the rear blade drive lever 50 are all located at the release position or the return position, as shown in FIG. , The front blade group 20 is located at an open position where the opening portions 10a (11a, 12a) are overlapped and open, and the rear blade group 30 is developed upward to open the opening portion 10a.
(11a, 12a) is located in the closed position to close. Further, the movable shielding plate 70 is located at an open position (a retracted position) where the through hole 10c for the leading blade is opened. At this time, as shown in FIG.
c is shielded by the link members 25 and 26 of the leading blade group 20 and the like.

Subsequently, from a control unit provided in the camera,
When a control signal for setting the charge of the shutter is issued, the drive motor and the like are started, and the set lever 60 starts rotating counterclockwise from the release position toward the set position. 4 by the action of the set lever 60.
As shown in (1), the leading blade drive lever 40 is rotated clockwise and the trailing blade drive lever 50 is rotated clockwise, and a state is reached in which the shutter charge is set. Further, the movable shielding plate 70 is rotated clockwise to reach the shielding position.

At this time, as shown in FIG.
0 moves downward and unfolds to open the openings 10a (11a, 12a).
a) is located in the closed position where the rear blade group 30 is moved downward to overlap and overlap with the opening portions 10a (11a, 12a).
Is located at the open position where is opened. That is, the front blade group 2
The opening 10a (11a, 12a) is closed by only 0. In addition, as shown in FIG.
The through hole 10 c for the front blade is provided with the shielding portion 7 of the movable shielding plate 70.
On the other hand, the rear blade through-hole 10 d of the main plate 10 is shielded by the link members 35 and 36 of the rear blade group 30. That is, in the state where the charge of the shutter is set, the through hole 10c for the front blade is set.
Is shielded by the movable shielding plate 70 instead of being opened, so that light can be prevented from entering the rear side of the base plate 10 from this region. In particular, light that has entered from the region of the cutout hole 10b via a gap or the like is prevented from entering the back side of the base plate 10 due to reflection or the like. This ensures that the photographic film located on the rear side of the main plate 10 is shielded from light.

Subsequently, when the release operation is performed, first, the electromagnet 80 for the front blade and the electromagnet 90 for the rear blade are respectively energized, and the front blade driving lever 40 and the rear blade driving lever 50 are moved to their positions by suction. Will be retained. Then, as shown in FIG. 2 (c), the locked state at the set position is released, and the set lever 60 is rotated clockwise by the urging force of the torsion spring to return to the released position. 64 is disengaged from the first engaging portion 72 of the movable shielding plate 70, and the release pin 65 is engaged with the second engaging portion 73 of the movable shielding plate 70, and the movable shielding plate 7
0 is rotated counterclockwise.

At this time, as shown in FIG.
0 is located at a closed position where the opening 10a (11a, 12a) is closed, and the rear blade group 30 is located at the opening 10a (11a, 1a).
2a) is located in an open position where it is open. As shown in FIG. 5, the movable shielding plate 70 is positioned at an open position (a retreat position) where the through hole 10 c for the front blade of the main plate 10 is opened. After that, the energization to the front blade electromagnet 80 is cut off and the front blade group 20 runs toward the upper open position, and after a predetermined time (exposure time) has elapsed, the energization to the rear blade electromagnet 90 is cut off. The leaning rear blade group 30 travels toward the upper closed position, and the state shown in FIG. 3 is obtained. Thus, the exposure operation ends, and the subject is photographed.

After that, according to the control signal output from the control unit, following the sequence shown in FIGS. 2A and 2B, the leading blade group 20 closes the opening 10a (11a, 12a). And the rear blade group 30 is opened
It reaches the open position where (11a, 12a) is opened, and furthermore, the movable shield plate 70 reaches the shield position where it shields the through hole 10c for the leading blade, and waits in this state to prepare for the next photographing. In addition, when the camera is turned off and the photographing is completed, this state (the movable shielding plate 70 is moved to the front blade through hole 10).
c is shielded), and in the operation sequence of the camera, the case where it is held in this shielded state is the longest.

Accordingly, light is prevented from entering the back side of the base plate 10 from the region of the through hole 10c for the front blade, and in particular, light entering through the gap from the region of the cutout hole 10b is reflected or reflected. This further prevents the ground plate 10 from entering the rear side. Thereby, light-shielding of the photographic film located on the rear side of the main plate 10 is efficiently and reliably performed.

In the above embodiment, the movable shielding plate 70
Notch hole 10b for accommodating the support shaft of the reflection mirror
Is used to shield only the leading blade through-hole 10c located in the vicinity of the front blade, but is not limited to this, and adopts a configuration in which a movable shielding plate capable of blocking the trailing blade through-hole 10d is separately provided. It is of course possible to do so.

[0046]

As described above, according to the focal plane shutter of the present invention, the shutter blade group arranged on the back side of the substrate having the opening through which light passes and the front side of the substrate are arranged. A dedicated movable shield plate for performing a shielding operation and an opening operation is provided for a through hole in a region of a connecting portion that connects the driving lever to the drive lever, thereby improving light shielding properties for a photographic film on the back side of the substrate. be able to. Further, since the shutter blade group is configured separately and independently, the light shielding property can be improved without impairing the responsiveness and reliability of the opening / closing operation (exposure operation) by the shutter blade group. Further, by disposing the movable shielding plate in a plate shape on the substrate, the device can be reduced in size and simplified. In particular, by forming the movable shielding plate so as to shield the through hole when the charge of the shutter is set, light can be efficiently shielded in a standby state for photographing or in a power-off state. Also, by using the set lever used to operate the drive lever for driving the shutter blade group as the drive means of the movable shielding plate, it is possible to prevent an increase in the number of parts, to simplify the structure, to reduce the cost, etc. Can do it. Furthermore, by making the reflectivity of the movable shield plate smaller than the reflectivity of the portion that opens and closes the opening of the shutter blade group, light reflection and the like can be suppressed as much as possible, and the light blocking effect can be further improved. .

[Brief description of the drawings]

FIG. 1 is a plan view showing a substrate on which an opening constituting a part of a focal plane shutter according to the present invention is formed.

FIGS. 2A and 2B are plan views showing operations of a movable shield plate, a driving lever for driving a front blade group and a rear blade group, a set lever, and the like, and FIG. 2A is a plane showing a state before a shutter charge is set; FIG. 3B is a plan view showing a state where the shutter charge is set, and FIG. 3C is a plan view showing a state immediately after the release operation is performed.

FIG. 3 is a plan view showing a state of a movable shielding plate, a front blade group, a rear blade group, and the like before a shutter charge is set.

FIG. 4 is a plan view showing a state of a movable shield plate, a front blade group, a rear blade group, and the like in a state where a shutter charge is set.

FIG. 5 is a plan view showing a state of a movable shielding plate, a front blade group, a rear blade group, and the like immediately after a shutter release operation is performed.

FIG. 6 is a perspective view showing a conventional focal plane shutter.

FIG. 7 is a plan view showing a relationship between a through hole of a substrate and a group of shutter blades in a conventional focal plane shutter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Ground plate (substrate) 10a Opening, 10b Notch hole 10c Through hole for front blade (through hole), 10d Through hole for rear blade (through hole) 11 Intermediate plate 11a Opening 12 Cover plate 12a Opening 20 Front blade group (Shutter blade group) 25 Link member 25a Connection hole 26 Link member 30 Rear blade group (Shutter blade group) 35 Link member 35a Connection hole 36 Link member 40 Front blade drive lever 42 Connection pin (connection portion) 50 Rear blade drive lever 52 Connecting pin (connecting part) 60 Set lever (drive means) 62 First engaging part 63 Second engaging part 64 Set pin 65 Release pin 70 Movable shielding plate 71 Shielding part 72 First engaging part 72 Second engaging part 80 Electromagnet for front blade 90 Electromagnet for rear blade

Claims (6)

[Claims] 1. A shutter blade group movably arranged between a substrate having an opening for transmitting light and a closed position covering the opening and an open position opening the opening, the shutter blade group being disposed on the rear side of the substrate. And a drive lever disposed on the front side of the substrate to drive the shutter blades to reciprocate, and to allow movement of a connecting portion connecting a part of the drive lever and a part of the shutter blades. A through hole formed in the substrate,
A focal plane shutter comprising: a movable shielding plate movably disposed with respect to the substrate so as to shield and open the through hole; and a driving unit for driving the movable shielding plate. And a focal plane shutter. 2. The focal plane shutter according to claim 1, wherein said movable shield plate is driven so as to shield said through hole when a charge of a shutter is set. 3. A set lever rotatably disposed on a front side of the substrate so as to be engaged with the drive lever to set and release a charge of a shutter. The focal plane shutter according to claim 1, wherein the focal plane shutter also serves as a driving unit of the movable shielding plate. 4. The apparatus according to claim 3, wherein the set lever drives the movable shielding plate so as to open the through hole when the set lever is moved to a position where the charge of the shutter can be released. Focal plane shutter. 5. The shutter blade group includes a front blade group and a rear blade group, and the driving lever includes a front blade driving lever that drives the front blade group, and a rear blade driving lever that drives the rear blade group. The through-hole includes a through-hole for the front blade that allows movement of a connecting portion that connects a part of the front blade drive lever and a part of the front blade group, and one of the rear blade drive lever. And a rear blade through-hole that allows movement of a connecting portion that connects a portion and a part of the rear blade group, and the movable shielding plate can shield and open at least the front blade through-hole. The focal plane shutter according to claim 3, wherein the focal plane shutter is disposed. 6. The focal point according to claim 1, wherein the reflectance of the movable shielding plate is smaller than the reflectance of a portion of the shutter blade group that opens and closes the opening. Plane shutter.