JPH112854A - Focal-plane shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focal-plane shutter for a camera in which a space for housing a front blade group, a rear blade group, and a light shielding blade group is not required to be large in an optical direction though it is provided with the light shielding blade group in addition to the front blade group and the rear blade group. SOLUTION: The blades 4, 5, 6 and 7 of the front blade group are arranged between a shutter base plate 1 and an intermediate plate 2; and the blades 8, 9, 10 and 11 of the rear blade group and the blades 12, 13, 14 and 15 of the light shielding blade group are arranged between the plate 2 and a cover plate 3. In a set condition, the blades 4, 5, 6 and 7 of the front blade group and the blades 12, 13, 14 and 15 of the light shielding blade group are in a developed condition and cover an aperture for exposure, so that light entering from an aperture part 1a is shielded so as not to leak and reach a film. Thus, since the plural blades of the rear blade group and the plural blades of the light shielding blade group are arranged in the same blade chamber, the housing space in the optical direction is prevented from being large.

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 in which a group of front blades and a group of rear blades are sequentially moved in the same direction during photographing, and a film is exposed by slits formed by the groups. About.

[0002]

2. Description of the Related Art As single-lens reflex cameras become smaller and have higher performance, this type of focal plane shutter is also required to be smaller and faster. As is well known, the focal plane shutter is disposed immediately before the film surface. Therefore, in order to reduce the size of the planar shape (the size of the surface orthogonal to the optical axis), the focal plane shutter needs to be placed in an overlapping state ( It is effective that the space for storing the blades in the state of being retracted from the exposure opening) can be reduced. However, for that purpose, it is necessary to reduce the width of each blade in the developing direction and at the same time increase the number of blades. When the number of blades is increased, the number of overlapping surfaces of the blades in the unfolded state (the state covering the exposure opening) increases, so that the weight of the entire blade and the sliding friction force inevitably increase. Would. Therefore, there is a problem that at least the blades must be reduced in weight in order to obtain the conventional traveling speed by the conventional driving force.

On the other hand, in order to increase the shutter speed (exposure time), it is necessary to increase the driving force (spring force) or reduce the weight of the blade. However, it is extremely difficult to increase the driving force more than ever from the viewpoint of obtaining stable performance and from the viewpoint of productivity. Therefore, it is important to reduce the weight of the blades in order to cope with higher speeds. By the way, reducing the weight of a blade means reducing the plane area or reducing the thickness of each blade, if the material surface is not considered. However, when the plane area of each blade is reduced, the overlapping area of the blades in the unfolded state is reduced, and light leakage to the film surface when the camera is not used becomes a problem. On the other hand, if the thickness of each blade is too small, the blade may bend significantly due to vibration or impact when the camera is carried, and harmful light leakage may also occur. Another problem is that it becomes difficult to withstand the impact at the end of the exposure travel.

As described above, in order to reduce the size and speed of the shutter, it is necessary to take measures against light leakage between the blades when the camera is not used. More recently, high-sensitivity films (for example, ISO 160
This is even more so because 0) has come to be used favorably. Therefore, in manufacturing the shutter, various efforts have been made in terms of surface treatment and structure.
Among them, an example of an extremely effective method for solving the problem structurally is described in JP-A-54-151439.

This conventional example is generally called a double light-shielding method. When the shutter is set in conjunction with the film winding after the photographing is completed, the front blade group is driven by the front blade. It moves to the set position with the member,
The rear blade group does not immediately operate to the set position, and only the rear blade drive member operates to the set position. Then, when the next photographing is performed, the rear blade group is moved to the set position (exposure operation start position) in the initial stage of the release. Therefore, when the camera is not used, the exposure opening is always covered by the front blade group and the rear blade group, and light leakage can be prevented.

[0006] However, in the double light shielding system having such a configuration, the normal rear blade driving member is divided into two members.
In addition to complicating the configuration of important components for exposure operation, such as applying a spring between them, the rear wing group moves to the set position at the initial stage of release, so it bounces at that position However, there is a problem that the exposure operation cannot be started until the temperature falls into a stable state. Therefore, although the number of parts may increase somewhat, a configuration that enables the double light shielding method without changing the configuration and the operation mode of the rear blade system has been proposed.
No. 53623.

In this conventional example, in addition to the front blade group and the rear blade group, another set of blade groups called a light-shielding blade group is provided. Then, when the shutter is set in conjunction with the film winding after the photographing is completed, the leading blade group and the trailing blade group are moved to the set position together with the respective driving members by the setting member, and the light shielding blade group is also set at the same time. The member is operated from the superposed state to the deployed state. for that reason,
When the shutter is set, the front blade group and the light shielding blade group are both in the deployed state and cover the exposure opening, so that light leakage when the camera is not used can be prevented. Then, when the next photographing is performed, in the initial stage of the release, the light-shielding blade group returns to the superimposed state as the set member returns to the initial position. The present invention relates to a double light-shielding focal plane shutter including a light-shielding blade group in addition to the front blade group and the rear blade group.

[0008]

By the way, in a focal plane shutter provided with a light-shielding blade group in addition to the front blade group and the rear blade group, the above-mentioned Japanese Utility Model Publication 4-5362.
As can be seen from the description of JP-A No. 3, each blade group is housed in a separate blade chamber. This is to prevent each blade group from interfering with other blade groups in operation. However, as a result, the conventional blade chamber needs only two chambers, whereas
Since it becomes a chamber, the dimension of the entire shutter in the optical axis direction must be increased. This places restrictions on the layout of other parts in the camera, especially
In the case of a single-lens reflex camera, the mounting position of the mirror must be moved to the lens side, which goes against the demand for miniaturization of the camera, which has been a serious problem.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. It is an object of the present invention to provide a light shielding blade group in addition to a front blade group and a rear blade group in order to prevent light leakage. The present invention provides a focal plane shutter for a camera that does not require a large accommodation space in the optical axis direction for all the blade groups for the light-shielding blade group.

[0010]

In order to achieve the above object, a focal plane shutter according to the present invention has a plurality of blades, and the exposure aperture starts from a superimposed position retreating from the exposure aperture at the time of setting. A front blade group actuated to a developing position covering the first blade group, and an exposure opening at the time of setting in a space having a plurality of blades and at least a part of which is partitioned by an intermediate plate in an operation space of the front blade group. A rear blade group that is operated from a development position covering the exposure opening to a superimposed position that retreats from the exposure opening, and has a plurality of blades and is arranged in an operation space of the rear blade group, and is used for exposure when set. A light-shielding blade group that is operated from the superimposed position retreating from the opening to the development position and covers at least a part of the exposure opening at the development position. The superimposed position of the serial trailing blade unit is constructed such that the opposite side of the exposure opening. In the focal plane shutter of the present invention, preferably,
At the time of setting, the rear blade group is configured to reach the overlapping position before the light shielding blade group reaches the deployment position. In the focal plane shutter according to the present invention, preferably, the working space of the front blade group is located on the lens side, and the working space of the rear blade group and the light shielding blade group is located on the film side. . Further, in the focal plane shutter according to the present invention, preferably, the number of blades of the light-shielding blade group is smaller than the number of blades of the front blade group.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to three illustrated embodiments. FIGS. 1 and 2 are sectional views showing a first embodiment, FIGS. 3 and 4 are sectional views showing a second embodiment, and FIGS. 5 and 6 are sectional views showing a third embodiment. FIGS. 1, 3 and 5 show the setting state of the shutter, and FIGS. 2, 4 and 6 show the state immediately after the end of the exposure operation of the shutter. In each of the drawings, in order to make it easier to understand the relative relationship between the respective blades described later, the plate thickness of each of the blades is larger than the actual one and the distance between the respective blades is large. Therefore, inevitably, the interval between the shutter base plate 1, the intermediate plate 2, and the cover plate 3 is drawn relatively wider than it actually is.

First, the configuration of the first embodiment will be described with reference to FIGS. Although shown in a cross-sectional view, as is well known, an opening 1 a is formed at a substantially central portion of the shutter base plate 1. An intermediate plate 2 and a cover plate 3 are sequentially attached by a suitable method on the back side (the right side in the figure) of the shutter base plate 1 when viewed from the subject side, that is, the lens side. The openings 2a and 3a are also formed in the intermediate plate 2 and the cover plate 3. And, in fact,
The three openings are not formed in the same shape, and an exposure opening as a shutter unit is determined by combining them. In the present embodiment, the openings 1a,
The description will be made on the assumption that 2a and 3a have the same shape, that is, that each opening regulates the exposure opening.

The two spaces formed between the shutter base plate 1, the intermediate plate 2, and the cover plate 3 are blade chambers. As is well known, the intermediate plate 2 has the smallest area on a plane. Actually, two blade chambers are connected near a pivot portion of the arm described later. In the case of the present embodiment, a group of leading blades is arranged in a blade chamber formed between the shutter base plate 1 and the intermediate plate 2, and a blade chamber formed between the intermediate plate 2 and the cover plate 3 is provided in the blade chamber. Is a group of rear blades. However, the present invention is not limited to such an arrangement, and the front blade group is provided in a blade chamber formed between the intermediate plate 2 and the cover plate 3.
Further, the rear blade group may be arranged in a blade chamber formed between the shutter base plate 1 and the intermediate plate 2.

The front blade group is composed of a plurality of arms (not shown), which are well known, and four front blades 4, 5, 6, and 7 respectively pivotally supported by them. 4
Are the slit forming blades of the front blade group. Each of the above-mentioned arms is pivotally attached to the shutter base plate 1, and is reciprocally rotated by a leading blade driving member (not shown) as is well known. At the time of photographing, when the driving member for the front blade is released from the electromagnet for the front blade (not shown) and rotated by the driving spring for the front blade, each of the front blades 4, 5, 6, and 7 is moved through the arm. 1 is actuated downward from the position shown in FIG. 1 and, as shown in FIG. 2, is superimposed and stored in a position below the opening 1a. Thereafter, the driving member for the leading blade is driven by a set member (not shown). When rotated against the force of
Numeral 7 operates upward and unfolds to cover the exposure opening as shown in FIG.

The rear blade group of this embodiment has basically the same configuration as the above-mentioned front blade group. Although only four rear blades 8, 9, 10, and 11 constituting the rear blade group are shown in the drawing, the rear blade 8 is a slit forming blade. Further, the arm constituting the rear blade group is configured to be reciprocally rotated by a rear blade driving member (not shown). At the time of photographing, the rear blade driving member is moved to the rear blade driving member (not shown). When released from the electromagnet and rotated by the rear blade drive spring, the respective rear blades 8, 9, 10, and 11 operate downward via the arms, and as shown in FIG. When the shutter is set and the rear blade driving member is rotated against the force of the driving spring when the shutter is set, the rear blades 8, 9, 10, and 11 operate upward while overlapping, and FIG. Is stored as shown in FIG.

Further, in this embodiment, a light-shielding blade group is disposed in a blade chamber in which the rear blade group is disposed. The light-shielding blade group includes four light-shielding blades 12, 13, and 1.
4, 15 and each light-shielding blade is pivotally attached to a shutter base plate in the same manner as in the conventional example described in Japanese Utility Model Publication No. 4-53623 described above. When the charging lever is in the set position, the charging lever is in a developed state as shown in FIG. 1 and covers the exposure opening. When the set member is operated from the set position prior to the operation of the front blade group during photographing, each of the light shielding blades 12, 13, 14, and 15 is operated.
Operate downward while overlapping, and are stored as shown in FIG. Conversely, when the set member is operated to the set position, each of the light shielding blades 12, 13, 14, and 15 is operated upward while being deployed, and is in a state as shown in FIG.

In this embodiment, as can be seen from FIG. 2, the vertical dimension of each of the light shielding blades 12, 13, 14, 15 is smaller than the vertical dimension of each of the front blades 4, 5, 6, 7. ing. In the present embodiment, the above-mentioned actual fairness 4
Similarly to the conventional example described in JP-A-53623, the respective light shielding blades 12, 13, 14, and 15 are pivotally attached to the shutter base plate. However, in the present invention, in the same manner as the above-mentioned front blade group, The light-shielding blade group may be composed of a plurality of arms and four light-shielding blades 12, 13, 14, and 15 pivotally supported by the arms, and the arms may be reciprocated by a set member. However, in this case, the arm of the light-shielding blade group and the arm of the front blade group should be arranged in a mutually preferable arrangement, instead of pivoting the arm of the light-shielding blade group to the shutter base plate 1. And the cover plate 3. Further, needless to say, the leading blade of the present embodiment,
The surfaces of the rear blade and the light shielding blade are each subjected to antireflection processing.

Next, the operation of this embodiment will be described. FIG. 1 shows a set state of the shutter. In this state, the rear blades 8, 9, 10, and 11 are superimposed and retracted upward from the exposure opening to be in a stored state. Also, the front blade 4,
5, 6, 7 and the light shielding blades 12, 13, 14, 15 are developed to cover the exposure opening. However, the shading blade 1
The upper end of 2 is located at substantially the same position as the upper end of the opening 3a, and a predetermined interval is maintained between the lower end of each of the rear blades 8, 9, 10, and 11. In this state, a part of the light entering from the opening 1a of the shutter base plate 1 enters the overlapping portion of the front blades 4, 5, 6, 7 even if the intermediate plate 2
Of the light passing through the opening 3a of the cover plate 3 toward the film surface,
Attenuation occurs at 2, 13, 14, and 15. Therefore,
Even if the light reflected by the light-shielding blades 12, 13, 14, 15 enters the overlapping portion of the light-shielding blades 12, 13, 14, 15 later, it is further attenuated at that time. However, it does not cause any harm to the film.

When a release is performed in such a set state, first, a well-known electromagnet for the front blade and a electromagnet for the rear blade (not shown) are energized, and the driving members for the front blade and the rear blade are driven. The member is magnetically attracted and held at the set position, and the set member is caused to retract from the set position. At this time, the light-shielding blade group also operates in conjunction with the set member, and the light-shielding blades 12, 13, 14, and 15 are superimposed and stored under the exposure opening. Next, when the power supply to the electromagnet for the front blade is cut off and the holding force of the electromagnet is lost, the driving member for the front blade is rotated by the driving spring for the front blade, and the front blade group is operated. Therefore, each front blade 4,
5, 6, and 7 run downward, open the exposure opening, and are stored in a superimposed state.

As can be seen from FIG. 2, in this state, a predetermined vertical distance is set between the upper ends of the front blades 4, 5, 6, 7 and the lower ends of the openings 1a and 2a. Have been. This is set to prevent the slit forming blade 4 from temporarily covering the exposure opening when the operation stops. Further, since the positions of the lower ends of the light-shielding blades 12, 13, 14, 15 are the same as the positions of the lower ends of the front blades 4, 5, 6, and 7, the light-shielding blades 12, 13, 14, 14,1
The vertical distance between the upper end of the upper blade 5 and the lower ends of the openings 2a and 3a is larger than the vertical distance in the case of the front blades 4, 5, 6, and 7 described above.

When a predetermined time has elapsed since the operation of the front blade group, the energization of the electromagnet for the rear blade is cut off, the driving member for the rear blade is rotated by the driving spring for the rear blade, and the rear blade group starts operating. I do. Therefore, each rear blade 8, 9, 1
0, 11 run downward while developing and close the exposure opening, thereby ending the film exposure operation, that is, photographing. FIG. 2 shows this state. As described above, the upper and lower dimensions of each of the light shielding blades 12, 13, 14, 15 are as follows.
In this state, the position of the lower end (slit forming edge) of the slit forming blade 8 of the rear blade group is substantially smaller than the upper and lower dimensions of each of the front blades 4, 5, 6, and 7.
It has been operated to the upper end positions of 5, 6, and 7 and stopped. Therefore, it does not bounce at the time of stop, and does not open the exposure opening temporarily.
There is no interference with 4,15.

The setting operation of the shutter is performed by a setting member. When the set member is operated by the member on the camera body side, first, the front blade driving member is rotated against the front blade driving spring to operate the front blade group.
Therefore, each of the front blades 4, 5, 6, and 7 operates upward while being deployed, but when a part of the slit forming blades 4 overlaps with the slit forming blades 8 of the rear blade group, the rear blades are turned. Also, the driving member is rotated against the driving spring for the rear blade,
Activate the rear wing group. Then, the set member further operates the light shielding blade group after the start of the operation of the slit forming blade 8 of the rear blade group. Therefore, after that, each front blade 4,
5, 6, 7, and each light-shielding blade 12, 13, 14, 15 operate upward while being deployed, and each rear blade 8, 9, 10, 11 operates upward while overlapping. Then, the setting member stops in a state where each driving member is in contact with each electromagnet, and the setting of the shutter is completed. FIG. 1 shows this state.

As described above, according to the present embodiment, the light-shielding blade group is arranged in the blade chamber of the rear blade group, so that there is no need to provide a dedicated blade chamber for the light-shielding blade group as in the related art. Accordingly, the size in the optical axis direction can be reduced (thinned) by that amount, and the size of the camera can be easily reduced.
Further, as described above, each of the light shielding blades 12, 13, 14, 1
5 is smaller than the top and bottom dimensions of each of the front blades 4, 5, 6, and 7, each of the rear blades 8, 9, 10, and 11 is configured such that its slit forming blades 8 1
It is possible to achieve a predetermined deployed state without interfering with 3, 14, and 15.

Also, as described above, each light-shielding blade 12, 1
By reducing the vertical dimension of 3,14,15,
It is not necessary to lower the storage position of each of the light shielding blades 12, 13, 14, 15 to a lower position than before, and there is an advantage that it is not necessary to increase the dimensions below the intermediate plate 2 and the cover plate 3. Further, as shown in FIG. 1, in the set state, the upper end of the light-shielding blade 12 is substantially located at the position of the upper end of the openings 2a, 3a, so that each of the rear blades 8, 9, 10,.
There is also an advantage that it is not necessary to raise the storage position of 11 to an upper position than before, and it is not necessary to increase the dimensions above the intermediate plate 2 and the cover plate 3.

Next, a second embodiment will be described with reference to FIGS. FIG. 3 shows a set state, and FIG. 4 shows a state immediately after the end of the exposure operation. This embodiment has a configuration in which the light shielding blade 15 is removed from the configuration of the first embodiment. Therefore, the same reference numerals as in the first embodiment are used for the respective components and their parts. Also, a known shutter configuration (not shown) is the same as that of the first embodiment. Accordingly, the operation of this embodiment is substantially the same as that of the first embodiment, and the description thereof will be omitted. Further, in the above description of the first embodiment, the advantages described in comparison with the conventional example are the same as those of the first embodiment.
Everything is available.

Thus, the features of the configuration of the present embodiment will be described. Needless to say, when the shutter is mounted on the camera, the upper and lower portions of FIGS. 3 and 4 are shielded from light by appropriate means in principle. Alternatively, there is no problem even if no special light shielding means is provided. This is exactly the same in each drawing of the first embodiment and each drawing of the third embodiment described later. Therefore, the light leakage countermeasures in the present invention are mainly for light entering from the opening 1a.

As is well known, in FIG.
The light that has entered enters between the shutter base plate 1 and the front blade 4, the overlapping portion of each of the front blades 4, 5, 6, and 7, and between the front blade 7 and the intermediate plate 2. Therefore, those lights enter from the lower left to the upper right in FIG. 3 as a whole. Among them, the light entering from between the shutter base plate 1 and the front blade 4 has a relatively large problem since the arm of the front blade group is usually arranged on the shutter base plate 1 side. The light that has entered from here generally travels above the opening 2a of the intermediate plate 2, attenuates by repeating reflection, and then enters the opening 2a toward the lower right.

However, the light is further attenuated by hitting the light-shielding blades 12, 13 and so on.
Even if a part of the light enters through the overlapping portion of the light shielding blades 12, 13, and 14, the light is already negligible,
Has substantially no effect on the film. Further, by repeating the reflection between each of the front blades 4, 5, 6, and 7 and each of the light shielding blades 12, 13, and 14, a part of the light that has traveled downward is covered with the cover plate 3 from below the light shielding blade 14. Although it may enter the side, the light has already been considerably attenuated. In addition, since the light enters the lower right direction, most of the light is reflected on the lower side of the opening 3a, and the light is repeatedly reflected before reaching the film surface.
Therefore, it has substantially no effect on the film.

Of the light that has entered from the overlapping portions of the front blades 4, 5, 6, and 7, most of the light that has directly entered the opening 2a hits the light shielding blades 12, 13, and 14. As a result, the light attenuated and reflected is further attenuated by the subsequent reflection, so that even if a part of the light passes through the opening 3a and reaches the film surface, the light is substantially exposed to the film. Never. Furthermore, the leading blade 7 and the intermediate plate 2
Although a part of the light that has entered from between passes through the openings 2a and 3a, the light is negligible and has substantially no problem. The reason is that the intermediate plate 2 does not bend as compared with the respective blades, so that the contact relationship between the leading blade 7 and the intermediate plate 2 at the overlapping portion is different from the contact relationship at the overlapping portion of the leading blades 4, 5, 6, 7 at the overlapping portion. 3, and the light entering from the lower part of the shutter base plate 1 is the light that has entered the opening 1a from the upper left to the lower right in FIG. 3 as a whole. This is because light that has been repeatedly attenuated and reflected by the lower portion of the intermediate plate 2 enters.

As described above, in the present embodiment, it is possible to prevent light leakage that adversely affects the film even though the number of the light shielding blades is three. In the present embodiment, the number of light-shielding blades is one less than that in the first embodiment, so that there is an advantage that the cost is reduced and the load on the set member is reduced.
Needless to say, the shutter light leakage countermeasures are usually taken in relation to the light leakage countermeasures on the camera body side. Therefore, for example, in a state where the mirror of the single-lens reflex camera is lowered, when a relatively large amount of light is reflected toward the shutter from around the mirror, particularly below the mirror, as in the first embodiment, If the configuration is relatively small, it may be possible to configure the configuration as in this embodiment. Therefore, when the amount of light reflected toward the shutter is further reduced, it is possible to further omit the light shielding blade 14 in this embodiment. In this case, it is more effective to set the positions of the light shielding blades 12 and 13 in the set state to a position slightly lower than the position in FIG.

Next, a third embodiment will be described with reference to FIGS. FIG. 5 shows the set state, and FIG. 6 shows the state immediately after the end of the exposure operation. The member configuration of the present embodiment is substantially the same as the configuration of the first embodiment. Therefore, the same reference numerals as in the first embodiment are used for the respective components and their parts. Also, the configuration of a well-known shutter (not shown) is the same as that of the first embodiment, so that the description of the configuration and the operation of this embodiment will be omitted to avoid duplication. Further, the advantage over the conventional example described in the description of the first embodiment is also provided in the present embodiment.
It is similarly obtained.

This embodiment differs from the first embodiment in that, as can be seen from FIG.
2 is at a position lower than the upper end of the opening 3a. This is extremely simple by designing the connection relationship between the light-shielding blade group and the set member,
Accordingly, the vertical dimension of each of the light shielding blades 12, 13, 14, 15 can be made smaller than in the case of the first embodiment. Even with such a configuration, most of the reflected light travels obliquely with respect to the optical axis, so that the reflected light rarely enters the opening 3a from the upper end of the light-shielding blade 12, and the light that enters is Since the light is considerably attenuated after repeated reflection, there is substantially no adverse effect on the film.

This embodiment has the advantage that the shutter can be made smaller than that of the first embodiment. That is, in the present embodiment, since the upper end of the light shielding blade 12 at the set position is at a lower position than in the case of the first embodiment, the rear blades 8, 9, 10, 11 stored in a superimposed state. Connect the lower end to the opening 2a,
3a. For this reason, in the present embodiment, the openings 1a,
The dimensions up to the upper ends of 2a and 3a are shorter than those in the first embodiment, and the vertical dimension of the entire shutter is reduced accordingly. As is well known, unlike the exposure operation, it is not necessary to consider the above-described bound at the time of the set operation. Even in this case, from the viewpoint of the light shielding effect, it is preferable that the upper end of the light shielding blade 12 be as close as possible to the lower end of each of the rear blades 8, 9, 10, 11 within a range that does not interfere. .

In each of the above embodiments, the front blade group is disposed between the shutter base plate 1 and the intermediate plate 2, and the rear blade group and the light shielding blade are disposed between the intermediate plate 2 and the cover plate 3. In the present invention, the rear blade group and the light shielding blade group are disposed between the shutter base plate 1 and the intermediate plate 2, and the front blade group is disposed between the intermediate plate 2 and the cover plate 3. May be arranged. However, the arrangement as in the embodiment is more advantageous in exhibiting the effect even on the light entering from the opening 1a. Further, in each embodiment, each blade group travels from above to below at the time of shooting, but the present invention is also applicable to a shutter that travels from below to above. Further, the number of blades of each blade group in the present invention is not limited to the number of blades in the above-described embodiment.

[0035]

As described above, according to the present invention, in order to prevent light leakage, the light-shielding blade group is provided in addition to the front blade group and the rear blade group. Since it is not necessary to increase the accommodation space in the optical axis direction required for accommodation, and it can be configured to be thinner in the optical axis direction than before,
Extremely effective.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a first embodiment, showing a set state of a shutter.

FIG. 2 is a cross-sectional view of the first embodiment, showing a state immediately after an exposure operation of a shutter is completed.

FIG. 3 is a cross-sectional view of the second embodiment, showing a setting state of a shutter.

FIG. 4 is a cross-sectional view of the second embodiment, showing a state immediately after the exposure operation of a shutter is completed.

FIG. 5 is a cross-sectional view of the third embodiment, showing a setting state of a shutter.

FIG. 6 is a cross-sectional view of the third embodiment, showing a state immediately after an exposure operation of a shutter is completed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a, 2a, 3a Opening 2 Intermediate plate 3 Cover plate 4,5,6,7 Front blade 8,9,10,11 Rear blade 12,13,14,15 Light shielding blade

Claims (4)

[Claims] A first blade group having a plurality of blades and being operated from a superimposed position retreating from the exposure opening to a developing position covering the exposure opening during setting, and a plurality of blades; In the operation space of the front blade group and a space at least a part of which is partitioned by the intermediate plate, after being operated from a development position covering the exposure opening to a superimposed position retreating from the exposure opening at the time of setting. The blade group, which has a plurality of blades, is arranged in the working space of the rear blade group and is operated from the superposed position retreated from the exposure opening to the developing position at the time of setting, to the developing position at the developing position. A light-shielding blade group that covers at least a part thereof, wherein a superposition position of the light-shielding blade group and a superposition position of the rear blade group are on opposite sides of the exposure opening. is being done A focal plane shutter. 2. The focal plane shutter according to claim 1, wherein at the time of setting, the rear blade group reaches the overlapping position before the light shielding blade group reaches the deployment position. 3. The operation space of the front blade group is located on the lens side, and the operation space of the rear blade group and the light-shielding blade group is arranged on the film side. 3. The focal plane shutter for a camera according to 1 or 2. 4. The focal plane shutter for a camera according to claim 1, wherein the number of blades of the light-shielding blade group is smaller than the number of blades of the front blade group.