JPH11183963A - Camera incorporating focal-plane shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera incorporating a focal-plane shutter capable of detecting the abnormal actuation of a blade group without forming a hole or a notch on an intermediate plate or a blade pressing plate. SOLUTION: A photointerrupter 21 is attached to cover the hole 1k formed on a shutter bottom board 1, so that detecting light is radiated toward a reflection sheet 22 stuck to an auxiliary bottom board 3 and reflected light is detected. The intermediate plate 2 and two blade pressing plates 13 and 20 are made of transparent material, and surface-processing having reflection preventing ability and lubricity is performed on their both surfaces except the optical path areas of the detecting light 2b, 13a and 20a. Therefore, the blades 9, 10, 11 and 12 of a front blade group and the blades 16, 17, 18 and 19 of a rear blade group are smoothly actuated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having a built-in focal plane shutter capable of checking the operating state of a group of blades performing an exposure run by photoelectric detection means.

[0002]

2. Description of the Related Art The front blade group and the rear blade group in a normal focal plane shutter each have a parallel link structure in which a plurality of blades are pivotally supported on two arms each having one end pivotally connected to a shutter base plate. Exposure travel is performed by a front blade drive member and a rear blade drive member that are operated by being biased by the respective drive springs. The exposure travel is started when the electromagnet for the front blade and the electromagnet for the rear blade are sequentially demagnetized. Therefore, if foreign matter adheres to the attracting surface of the electromagnet, the circuit of the electromagnet is cut off, or the supply voltage to the electromagnet drops, the required attracting force of the electromagnet cannot be obtained, and each of the blade groups has a predetermined strength. The operation may be started earlier than the operation start time.

In a normal case, the two drive members are operated to the set position by one set member. However, if the set stroke is insufficient, one or both drive members are not operated to the set position. However, there is a case where the operation is started when the predetermined operation start time is not reached. Further, although this type of shutter mechanism is manufactured so that the exposure travel of the leading blade group and the trailing blade group can be stably obtained for a long period of time, it is composed of many parts. Therefore, there is a case where the exposure traveling of the front blade group and the rear blade group is not performed at an appropriate timing.

Therefore, as a method for detecting such an abnormal operation of each blade group, a method using a mechanical switch mechanism has been conventionally known in Japanese Patent Application Laid-Open No. 9-244098. Japanese Patent Application Laid-Open No. 9-
This is known from Japanese Patent Publication No. 258296 and the like. The present invention relates to a camera provided with the latter type of detecting means, and two types of known types are known depending on the detection position of the blade.

[0005] First, the first configuration is described in Japanese Patent Laid-Open No.
As in the first embodiment described in Japanese Patent Application Laid-Open No. 258296, the side where the arm of each blade group is pivotally attached, that is, the base side of the blade that is pivotally supported by the arm, as viewed from the exposure opening. This is to be detected by. According to this configuration, a hole for a detection optical path is formed in the intermediate plate that partitions the working space of each blade group, so that light reflected from the cover plate can be detected.

A second configuration is disclosed in Japanese Patent Application Laid-Open No. 9-25 / 1997.
No. 8296, the second embodiment described in
As described in Japanese Patent Application Laid-Open No. 211444, detection is performed on the tip end side of the blade when viewed from the opening for exposure. In the case of this configuration, generally, Japanese Unexamined Patent Application Publication No.
As described in Japanese Patent Publication No. 11444, the tip of the blade of each blade group has an intermediate plate (a partition plate in this publication) having an opening, and a blade arranged only in an operation area of the tip of the blade. Since it is sandwiched between the holding plates (partition plate in this publication), holes for the detection optical path are formed not only in the intermediate plate but also in the blade holding plate, so that the reflected light from the cover plate can be detected. ing.

[0007]

However, it is problematic to form holes in the above-mentioned intermediate plate and blade holding plate. As is well known, these plates are made of very thin plates and are brought into contact so that the blades can slide properly. Therefore, if a hole or notch is formed in the detection optical path,
The strength is weakened depending on the formation location and shape, and it is difficult to appropriately suppress blurring (displacement or bending in the optical axis direction) of the blade during exposure traveling, which is not preferable. Further, during the exposure traveling, the end face in the traveling direction of the blade is caught by the edge of the hole or the notch, and it becomes difficult to obtain proper operation characteristics. Therefore,
Japanese Patent Application Laid-Open No. Hei 8-21444 also proposes a shape of a hole. However, even if a certain effect can be considered, if the blade is extremely lightweight and thin as in recent years, it is inevitable that the running speed is slightly affected while the blade is running. Such an effect is more likely to occur when the hole is formed on the tip side of the blade.

The present invention has been made to solve such a problem, and an object thereof is to form a blade group without forming holes or cutouts in an intermediate plate or a blade holding plate. An object of the present invention is to provide a camera with a built-in focal plane shutter capable of detecting an abnormal operation.

[0009]

In order to achieve the above object, a camera having a focal plane shutter according to the present invention is connected to a first shutter base plate arranged on the lens side in the camera and to the camera. A second shutter base plate disposed on the image plane side, an intermediate plate forming a partition between the first shutter base plate and the second shutter base plate and forming a blade chamber of the front blade group and a blade chamber of the rear blade group; Photoelectric detection means for irradiating the two blade chambers from one shutter base plate side and detecting light reflected from the second shutter base plate to detect at least one operation state of the blade group; The plate is manufactured by performing an anti-reflection treatment on both sides of a transparent plate material except for the optical path region of the light. In the camera of the present invention, preferably, at least one of the two blade chambers is provided with a blade holding plate so that a part of each blade of the blade group is sandwiched between the intermediate plate and the blade plate. At least one of the blade holding plate and the intermediate plate is manufactured by performing an anti-reflection treatment on both surfaces of a transparent plate material except for an optical path region of the light.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to an embodiment shown in an exploded perspective view of FIG. An intermediate plate 2 and an auxiliary base plate 3 are attached to the shutter base plate 1 at a predetermined interval, constitute two blade chambers therebetween, and have a substantially rectangular shape by combining the respective openings 1a, 2a, 3a. Are formed. In the camera, the shutter base plate 1 is arranged on the lens side, and the auxiliary base plate 3 is arranged on the imaging surface side, that is, on the film surface side when a film is loaded. Shafts 1b, 1c, and 1d are provided upright on the front side of the shutter base plate 1, and the shafts 1b and 1c are provided with a front blade driving member 4 and a rear blade driving member 5, both of which are made of synthetic resin. A set member 6 also made of a synthetic resin is rotatably attached to the shaft 1d.

Driving member 4 for front blade and driving member 5 for rear blade
Is urged to rotate clockwise by a front blade drive spring and a rear blade drive spring, not shown,
Iron pieces (not shown) are attached to the attachment portions 4a and 5a. The set member 6 is urged by a spring (not shown) to rotate counterclockwise.
Immediately after the exposure operation of the shutter is completed, the shutter is stopped at the initial position by the stopper. When the film is wound up, it is pushed by the member on the camera body side and rotates clockwise to rotate each of the driving members 4 and 5 in a counterclockwise direction. Make contact with each electromagnet not shown.

The front blade group is arranged between the shutter base plate 1 and the intermediate plate 2, and is composed of two arms 7, 8 and four blades 9, 10, 11, 12. The arm 7 has a shaft 1 e erected on the rear side of the shutter base plate 1.
The sleeve 7a is rotatably fitted, and the arm 8 is
A hole 8a is formed in the shaft 1f provided on the rear side of the shutter base plate 1.
Are rotatably fitted. Also, four blades 9.1
As is well known, 0, 11 and 12 are respectively pivotally supported on the arms 7 and 8 by two connecting shafts, and the blade 9 is a slit forming blade.

The drive pin 4b of the leading blade drive member 4 penetrates an arc-shaped long hole 1g formed in the shutter base plate 1 and fits into a long hole 7b formed in the arm 7. The tip is an arc-shaped long hole 3b formed in the auxiliary base plate 3.
Is fitted. Therefore, when the leading blade driving member 4 is rotated clockwise by the urging force of the leading blade driving spring (not shown), the blades 9, 10, 11, and 12 retreat from the exposure opening while overlapping, and the leading blade is rotated. When the driving member 4 for use is pushed by the set member 6 and rotates counterclockwise,
The blades 9, 10, 11, and 12 are configured to cover the exposure opening while developing.

A blade holding plate 13 is provided in an operating region at the tip of each of the blades 9, 10, 11, and 12. As is well known, the minimum size of the gap required in the optical axis direction differs between the blades 9, 10, 11, and 12 when they are superimposed and when they are deployed. For this reason, when the blades are superimposed, they overlap so closely that the displacement in the optical axis direction is limited, but the degree of freedom gradually increases as the blades are deployed, and the displacement in the optical axis direction increases. Is becoming possible. The displacement hinders proper operation. Therefore, the blade holding plate 13
Cooperates with the intermediate plate 2 and serves to close the overlap between the blades during operation.

On the other hand, the rear blade group includes an intermediate plate 2 and an auxiliary base plate 3.
And two arms 14, 15 and 4
The blades 16, 17, 18, and 19 are provided. The arm 14 has its sleeve 14a rotatably fitted on a shaft 1i provided on the rear side of the shutter base plate 1, and the arm 15 is mounted on a shaft 1j provided on the rear side of the shutter base plate 1. And the hole 15a are rotatably fitted. The four blades 16, 17, 18 and 19 are pivotally supported on the arms 14 and 15 by two connecting shafts, respectively, and the arms 14, 15 and the blades 16, 17, 18, and 19 overlap. The relationship is reversed from that of the front blade group. The blade 16 is a slit forming blade.

The drive pin 5b of the rear blade drive member 5 penetrates the arc-shaped long hole 1h formed in the shutter base plate 1 and fits into the long hole 14b formed in the arm 14. The tip is an arc-shaped long hole 3 formed in the auxiliary base plate 3.
c. Therefore, when the rear blade drive member 5 rotates clockwise by the urging force of the rear blade drive spring (not shown), the blades 16, 17, 18, and 19 cover the exposure opening while expanding, and When the rear blade drive member 5 is pressed by the set member 6 and rotates counterclockwise, the blades 16, 17, 18, and 19 retreat from the exposure opening while overlapping. And each wing 1
A blade holding plate 20 is provided in the operating region at the tip end of each of the blade holding plates 6, 17, 18, and 19, similarly to the above-described blade holding plate 13.

Further, in this embodiment, the operation of the leading blade group and the trailing blade group can be detected. That is, a rectangular hole 1k is formed in the shutter base plate 1, and the photoreflector 2 is formed so as to close the hole 1k.
1 is attached. As is well known, the photo reflector 21 is provided with a light emitting section and a light receiving section, and the detection light emitted from the light emitting section is reflected by the reflection sheet 22 attached to the auxiliary base plate 3, and is reflected by the light receiving section. It is configured to be incident. The intermediate plate 2 and the two blade holding plates 13 and 20 are made of a transparent sheet material such as polyester, so that the optical path regions 2b, 13a, and
Except for 20a, both surfaces are subjected to a surface treatment rich in anti-reflection properties and lubricity. Needless to say, other members are also subjected to such a surface treatment.

Next, the operation of this embodiment will be briefly described.
Immediately after the exposure operation is completed, the four blades 9, 10, 11, and 12 of the front blade group are superimposed and stored at a position below the opening 1a, and the four blades of the rear blade group are stored. The blades 16, 17, 18, and 19 are in the unfolded state and the opening 1
a. From this state, the set member 6 is set by the member on the camera body side in conjunction with the film winding.
Is rotated clockwise, the set member 6 first rotates the leading blade drive member 4 counterclockwise against a leading blade drive spring (not shown). Therefore, the four blades 9, 10, 11, and 12 of the front blade group are deployed upward while reducing the overlapping amount from the superimposed state.

The set member 6 does not show the rear blade drive member 5 when the overlap between the slit forming blades 9 of the front blade group and the slit forming blades 16 of the rear blade group reaches a predetermined amount. Start rotating counterclockwise against the rear blade drive spring. Therefore, the blades 16 and 1 of the rear blade group
7, 18, and 19 are superimposed upward while increasing the overlapping amount from the unfolded state. In this way, the leading blade group and the trailing blade group are operated together, and when the blades 9, 10, 11, 12 of the leading blade group eventually cover the opening 1a, the driving members 4, 5 The provided iron piece members (not shown) come in contact with the respective electromagnets successively, and at that stage, the rotation of the set member 6 is stopped. The setting member 6 is maintained in this state by the member on the camera body side.

When the release button of the camera is pressed during the next photographing, current is supplied to each of the electromagnets and the photoreflector 21 in the initial stage. Therefore, the iron piece member described above is magnetically attracted and held. The light emitted from the light emitting unit of the photo reflector 21 is
Since the light impinges on the front blade group, it is hardly reflected, and the L signal is output from the photo reflector 21. Thereafter, the set member 6 is rotated counterclockwise by the urging force of a spring (not shown) in conjunction with the member on the camera body side, and returns to the initial position. However, since the iron pieces are attracted by the electromagnets, the driving members 4 and 5 are not rotated clockwise by the driving springs.

At this time, if the coil of the electromagnet for the leading blade is disconnected, the driving member 4 for the leading blade is immediately rotated clockwise by the urging force of the driving spring for the leading blade, and the blades 9, 10, and 11 are rotated. , 12 are superimposed downward. Therefore, the light emitted from the light emitting unit of the photo reflector 21
Since the light is reflected by the reflection sheet 22 of the auxiliary base plate 3 and enters the light receiving unit, the H signal is output from the photoreflector 21. Then, it is confirmed that the output timing of the H signal is earlier than the normal output timing, and a warning of an abnormal operation is issued.

If the coil of the electromagnet for the rear blade is disconnected, the driving member 5 for the rear blade is immediately rotated clockwise by the urging force of the driving spring for the rear blade, and the blade 1 is rotated.
6, 17, 18, and 19 unfold and cover the opening 1a. Therefore, even if the front blade group subsequently operates normally, the H signal is not output from the photo reflector 21. Therefore, it is confirmed that the H signal is not output from the photoreflector 21 even though the front blade group is normally operated, and a warning of an abnormal operation is issued.

Therefore, when neither the leading blade group nor the trailing blade group performs the above-mentioned abnormal operation, the exposure time control circuit operates at the stage when all the preparatory operations such as automatic focusing are completed. Then, the energization of the electromagnet for the first blade is stopped, and the counting of the exposure time is started. Therefore, the leading blade driving member 4 is rapidly rotated clockwise by the urging force of the leading blade driving spring (not shown), and the H signal is output from the photo reflector 21. Thereafter, when a predetermined time has elapsed, the output signal from the exposure time control circuit
This time, the energization of the rear blade electromagnet is cut off, and the rear blade drive member 5 is rapidly rotated clockwise by the urging force of the rear blade drive spring (not shown). As a result, the L signal is output from the photo reflector 21. Is output and the exposure operation ends. At this time, if the time from when the H signal is output to when the L signal is output is compared with the time corresponding to the exposure time to be controlled, a predetermined appropriate operation may be performed for some reason. A warning can also be given of what was not done.

In this embodiment, the case where the photoreflector 21 is mounted on the shutter base plate 1 has been described, but this does not prevent the photoreflector 21 from being mounted on the camera body. Instead of the reflection sheet 22 attached to the auxiliary base plate 3, an appropriate process having a reflection effect may be applied to the surface of the auxiliary base plate 3. Further, the photoelectric detecting means of the present invention is not limited to the photoreflector, but may be configured to separately attach the light emitting section and the light receiving section.

In this embodiment, the intermediate plate 2 and the two blade holding plates 13 and 20 are both made of a transparent material, and are formed on both surfaces except for the optical path regions 2b, 13a and 20a of the detection light. Although the antireflection treatment is performed, the present invention is not limited to such a configuration, and only one of the members may be manufactured as described above. Recently, there has been known a shutter configuration in which at least one of the two ground plates 1 and 3 is made of synthetic resin, and the operating region at the tip of the blade is made thicker so that the blade holding plate is not provided. However, the present invention is also applied to a shutter having such a configuration. Further, when the detection is performed on the base side of the blade as in the first embodiment described in Japanese Patent Application Laid-Open No. 9-258296, only the intermediate plate is manufactured as described above. It will be good.

[0026]

As described above, in the present invention, when manufacturing the intermediate plate and the blade holding plate, a transparent plate material is adopted, and on both surfaces thereof, anti-reflection treatment is performed except for the optical path region of the detection light. Since the application is performed, there is no possibility that the traveling speed is affected during the traveling of the blade as compared with the case where holes or notches are formed. Therefore, the configuration for detecting abnormal operation of the blade group is extremely effective.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a, 2a, 3a Opening 1b, 1c, 1d, 1e, 1f, 1i, 1j Axis 1g, 1h, 3b, 3c, 7b, 14b Slot 1k, 8a, 15a Hole 2 Intermediate plate 2b, 13a, Reference Signs List 20a Optical path region 3 Auxiliary base plate 4 Front blade drive member 4a, 5a Attachment portion 4b, 5b Drive pin 5 Rear blade drive member 6 Set member 7, 8, 14, 15 Arm 7a, 14a Sleeve 9, 10, 11, 12 , 16,17,18,19 Blade 13,20 Blade holding plate 21 Photoreflector 22 Reflection sheet

Claims (2)

[Claims] 1. A first shutter base plate disposed on a lens side in a camera, a second shutter base plate disposed on an image forming surface side in a camera, and between a first shutter base plate and a second shutter base plate. And an intermediate plate forming a blade chamber of the front blade group and a blade chamber of the rear blade group, and light emitted from the first shutter base plate side into the two blade chambers and reflected from the second shutter base plate is detected. Photoelectric detecting means for detecting the operation state of at least one of the blade group, and the intermediate plate is manufactured by performing an anti-reflection treatment on both surfaces of a transparent plate material except for an optical path region of the light. A camera having a built-in focal plane shutter. 2. A blade holding plate is provided in at least one of the two blade chambers such that a part of each blade of the blade group is sandwiched between the intermediate plate and the blade holding plate. 2. The focal plane shutter according to claim 1, wherein at least one of the intermediate plates is manufactured by performing an anti-reflection treatment on both surfaces of a transparent plate material except for an optical path region of the light. Camera.