JPH09189936A - Light shielding device and camera provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light shielding device capable of reducing the fluctuation of the operation of plural light shielding blades having different shape caused by the posture of a camera and being made compact by making the material (specific gravity) and the thickness of the light shielding blades different so that the weight of each light shielding blade per unit area may differ. SOLUTION: When a coupling ring 4 is rotated, the shutter blades 1 and 2 are respectively rotated with parts 1a and 2a as the center of rotation so as to perform the opening/closing operation of a shutter. The shutter blade 1 has an ear part 1c on its outermost periphery part distant from the part 1a, and holes 1d, 1e and 1f detected by a photosensor are formed on the ear part 1c. The shutter blade 2 does not have the ear part 1c, its outside dimension is smaller than that of the blade 1. By making the blade 1 thinner in thickness than the blade 2, the weight of the blade 1 is made nearly the same as that of the blade 2, and force acting on the coupling ring 4 from both blades 1 and 2 in all the postures of the camera is cancelled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light shielding device used as a shutter device of a camera.

[0002]

2. Description of the Related Art A shutter device used in a camera with a lens shutter is provided with a plurality of shutter (light-shielding) blades that can be opened and closed. One of these shutter blades is used for light-shielding. In addition, it has a portion for forming a through hole for position detection.
When the shutter blade opens and closes, the position of the shutter blade is detected by passing the through hole in front of the optical sensor, and the detection result is used for exposure control of the camera.

[0003]

However, in the shutter device as described above, the outer shape and weight of the shutter blade having the position detecting portion are larger than those of the other shutter blades, so that the distance between the shutter blades is large. The weight balance will be lost. Therefore, the operating characteristics of the shutter device may vary depending on the attitude of the camera, that is, the shutter device.

It is possible to balance the weight of both shutter blades by adding a portion having the same shape as the position detecting portion to the other shutter blades, but this is disadvantageous in making the shutter device compact. become.

Therefore, an object of the first to ninth inventions of the present application is to provide a light-shielding device which has a plurality of light-shielding blades having different shapes, but has a small variation in the operating characteristics depending on the posture and can be made compact. It is in.

The object of the tenth to sixteenth inventions of the present application is to:
In particular, to provide a light-shielding device in which there is little variation in the operating characteristics due to the posture and the size can be reduced when one light-shielding blade is provided with a different shape for detecting the opening / closing operation by an optical sensor. is there.

The object of the seventeenth to twenty-second inventions of the present application is to reduce the variation of the operating characteristics due to the posture and to make the apparatus compact when the shapes of one light shielding blade are provided to drive the other light shielding blades. It is an object of the present invention to provide a light shielding device capable of achieving the above.

A further object of the inventions 23 and 24 is to provide a camera capable of performing stable exposure control regardless of the posture.

[0009]

In order to achieve the above object, in the invention of the first to ninth inventions of the present application, in a light-shielding device having a plurality of light-shielding blades having different outer shapes, the material (specific gravity) of the light-shielding blades and The weight per unit area of each light-shielding blade is changed by changing the thickness and the like.

That is, even though the plurality of light-shielding blades have different outer shapes, the weights and the moments of inertia about the opening and closing operation centers are made equal to each other, so that the weight balance is good, and the variation of the operation characteristics due to the posture is small. A compact shading device is realized. It should be noted that these inventions have a larger outer shape than the other light-shielding blades because one light-shielding blade has a portion used for position detection in the light-shielding opening / closing direction, like the inventions of the tenth to twenty-second aspects of the present invention. The present invention can be applied to the case where one light-shielding blade has a larger outer shape than the other light-shielding blades because it has a portion for driving the other light-shielding blades.

In the twenty-third and twenty-fourth aspects of the present invention, the above-mentioned light-shielding device is provided as a shutter device or the like, so that stable exposure control can be performed regardless of the posture and a compact camera is realized. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIGS. 1 to 3 show a first embodiment of the present invention. In these drawings, reference numeral 1 denotes a shutter blade, which is rotatably attached to a base plate (not shown) at a portion 1a. Further, there is an ear portion 1c at the outermost peripheral portion away from the rotational center 1a, and the ear portion 1c is formed with through holes 1d, 1e, 1f which are detected by an optical sensor described later.

Reference numeral 2 denotes a shutter blade, which is rotatably attached to a base plate (not shown) at a portion 2a. The shutter blade 2 has a smaller outer dimension than the shutter blade 1 because it does not have the ear portion 1c.

Reference numeral 3 is an optical sensor, that is, a photo interrupter, attached to a ground plate (not shown), and detects the through holes 1d, 1e, 1f provided in the ear 1c of the shutter blade 1 as the shutter blade 1 rotates. However, the rotation position and the rotation speed of the shutter blade 1 are measured. The camera corrects the exposure operation based on these data.

A connecting ring 4 is attached to a base plate (not shown) so as to be rotatable about the optical axis. Long holes 4a and 4b are formed at two locations in the circumferential direction of the connecting ring 4, one long hole 4a and a pin 1b fixed to the shutter blade 1 are slidably fitted, and the other one. Long hole 4b
And the pin 2b fixed to the shutter blade 2 are slidably fitted.

As a result, when the connecting ring 4 rotates, the shutter blade 1 and the shutter blade 2 are respectively 1a and 2a.
The unit rotates about the rotation center to open and close the shutter.

Reference numeral 5 denotes a drive gear, which is a gear portion 4 of the connecting ring 4.
mesh with c. Reference numeral 6 is a known motor, and the drive gear 5 is fixed to its output shaft. That is, the shutter is opened and closed by the normal rotation and the reverse rotation of the motor 6.

Reference numeral 7 shown by a chain double-dashed line in FIG. 2 indicates a maximum opening area defined by a ground plane (not shown). The shutter blades 1 and 2 are made of the same kind of material, but have different thicknesses. As shown in FIG. 3, which is a cross-sectional view, when the thickness of the shutter blade 1 is t1 and the thickness of the shutter blade 2 is t2, these relationships are t2> t1. Therefore, even though the shape of the shutter blade 1 is large, the shutter blade 1
The shutter blade 2 and the shutter blade 2 have almost the same weight.

As shown in FIG. 2, if the camera is in a posture in which the direction of arrow A of the shutter device is downward,
The shutter blade 1 tries to rotate in the direction to close the opening by gravity and the shutter blade 2 tries to rotate in the direction to open the opening. However, as described above, the shutter blade 1 and the shutter blade 2 have the same weight. The forces acting on the connecting ring 4 from the blades 1 and 2 are offset.

Similarly, if the camera is in a posture in which the arrow B direction of the shutter device faces downward, the shutter blade 1 tends to rotate in the direction to open the opening due to the weight, and the shutter blade 2 tends to rotate in the direction to close the opening. And The forces acting on the connecting ring 4 are canceled out because the shutter blades 1 and 2 have the same weight.

Similarly, even if the camera is in a posture in which the arrow C direction of the shutter device faces downward and the arrow D direction faces downward, gravity acts on the connecting ring 4 from the shutter blades 1 and 2. The forces are offset.

As described above, according to the present embodiment, even if one shutter blade has a detection portion such as an optical sensor, it is possible to maintain the weight balance with the other shutter blade, and to operate due to the attitude difference of the shutter device. It is possible to eliminate changes in characteristics.

Further, in order to keep the weight balance of the shutter blade, the shape of the shutter blade without the detecting portion is not matched with the large shutter blade with the detecting portion, so that the compactness of the shutter device can be maintained.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention, in which the shutter blades 1 and 2 are made of different materials having different specific gravities. The shutter blade 1 having a detection unit for detection by the optical sensor is made of a light material, for example, a resin material such as polyester, and the shutter blade 2 having a smaller outer dimension than the shutter blade 1 is made of a material having a high specific gravity, for example, a resin material. The one that has been plated is used. The 2c portion of the shutter blade 2 is a base material made of a resin material such as polyester, and the 2d portion on the surface thereof is plated with a metal such as nickel. Therefore, the material of the shutter blade 2 has a larger specific gravity than the material of the shutter blade 1 as a whole.

According to this, similarly to the first embodiment, the shutter blade 1 and the shutter blade 2 can have the same weight although the outer dimensions are different, and the change in the operating characteristics due to the attitude difference of the shutter device. Can be eliminated.

The materials of the shutter blades 1 and 2 are not limited to those described in the present embodiment, and any combination of materials having different specific gravities may be used.

Further, since the shutter blade 1 has an ear portion detected by an optical sensor such as a photo interrupter, the outer dimensions are larger than those of the other shutter blades 2. However, other methods such as magnetic method are used. It may be applied to the case where the shutter blade is larger than the other shutter blades because the position is detected at.

(Third Embodiment) FIGS. 5 and 6 show a third embodiment of the present invention. In addition to the shutter blade having a detection unit for position detection as in the first and second embodiments, the shape of a plurality of shutter blades may be different as in this embodiment. FIG. 5 shows an example thereof, and is an example in which the present invention is applied to a system in which one shutter blade drives another shutter blade.

In FIG. 5, reference numerals 11, 12, and 13 denote shutter blades, and 11a, 12a, and 13a portions are rotatably attached to a base plate (not shown).

A pin 11b is fixed to the shutter blade 11, and the pin 11b is attached to the cam groove 12c of the shutter blade 12.
It is slidably fitted with. A pin 12b is fixed to the shutter blade 12, and the pin 12b is attached to the shutter blade 13
It is slidably fitted in the cam groove 13c. This configuration is known from Japanese Patent Laid-Open No. 5-241223, and one shutter blade is driven to drive the other shutter blade.

As is apparent from FIG. 5, the shutter blade 1
Among the shutter blades 1, 12, and 13, the shutter blade 11 having no cam groove has a smaller outer dimension than the other shutter blades 12 and 13. However, as shown in FIG. 6, the plate thickness ta of the shutter blades 11 is larger than the plate thickness tb of the shutter blades 12 and the plate thickness tc of the shutter blades 13, and the weight balance of the shutter blades 11, 12, 13 is large. It is kept. Therefore, the shutter device is configured to prevent changes in the operating characteristics due to the attitude difference.

The shutter blade 11 is replaced by the shutter blade 1
The blades 11 to 13 may be manufactured using a material having a larger specific gravity than those of Nos. 2 and 13, and the weight balance of the blades 11 to 13 may be maintained.

In each of the above embodiments, the case where the present invention is applied to the shutter device of the camera has been described.
The present invention can also be applied to a diaphragm device of a camera.

Furthermore, the present invention may be used by combining the above-described embodiments and modified examples, or the technical elements thereof as needed.

In addition to the lens shutter camera of the above embodiment, the present invention can be applied to various types of cameras such as a video camera, and optical devices other than the camera. (Relationship Between Embodiment and Claims) In the above embodiment, the shutter blades 1, 12 and 13 are provided on the light shielding blades and the second light shielding blades having a large outer shape referred to in the claims, and the ear 1
The shutter blade 1 is attached to the position detecting portion c in the claims.
The portions in which the grooves 12c and 13c of 2 and 13 are formed respectively correspond to the driving portions in the claims.

The above is the correspondence relationship between each configuration of the present invention and each configuration of the embodiment, but the present invention is not limited to the configurations of these embodiments, and the mechanism or the embodiment shown in the claims is not limited. Any structure may be used as long as the function of the structure can be achieved.

[0037]

As described above, according to the present invention, even if the outer shapes of a plurality of light-shielding blades are different, the weight (open / close) of each light-shielding blade and the opening / closing of the light-shielding blade can be changed by changing the material (specific gravity) or thickness of the light-shielding blade. The moment of inertia about the center of motion is equal. Therefore, according to the present invention, even when a position detecting portion or a driving portion for another light shielding blade is added to one light shielding blade to cause a difference in outer shape from another light shielding blade, It is possible to realize a compact light-shielding device in which the weight balance of these light-shielding blades is good, the movement characteristics of the light-shielding blades do not fluctuate depending on the posture.

By providing such a shading device as a shutter device or the like, it is possible to realize stable exposure control and the like regardless of the posture and to realize a compact camera.

[Brief description of the drawings]

FIG. 1 is a perspective view of a shutter device (light blocking device) according to a first embodiment of the present invention.

FIG. 2 is a plan view of the shutter device according to the first embodiment.

FIG. 3 is a cross-sectional view of the shutter device according to the first embodiment.

FIG. 4 is a sectional view of a shutter device according to a second embodiment of the present invention.

FIG. 5 is a perspective view of a shutter device according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of the shutter device according to the third embodiment.

[Explanation of symbols]

 1, 2, 11, 12, 13 Shutter blades 1c Ears 1d, 1e, 1f (for position detection) through holes 12c, 13c (for driving) 3 Photo interrupter 4 Connecting ring 5 Drive gear 6 Motor

Claims (24)

[Claims] 1. A light-shielding device having a plurality of light-shielding blades having different outer shapes, wherein the weight per unit area of at least one of the plurality of light-shielding blades is different from the weight per unit area of other light-shielding blades. A shading device characterized by. 2. The weight per unit area of the light shielding blade having a larger outer shape than the other light shielding blades out of the plurality of light shielding blades is set to be smaller than the weight per unit area of the other light shielding blades. The shading device according to claim 1, wherein the shading device is provided. 3. At least one of the plurality of light shielding blades
3. The shading device according to claim 1, wherein the specific gravity of one material is different from the specific gravity of the material of the other shading blade. 4. A light-shielding blade having a larger outer shape than other light-shielding blades of the plurality of light-shielding blades is made of a material having a smaller specific gravity than the material of the other light-shielding blades. The shading device according to claim 3. 5. At least one of the plurality of light shielding blades
6. The light-shielding device according to claim 4, wherein one light-shield is formed only by a resin material, and the other light-shielding blades are formed by a plated resin material. 6. At least one of the plurality of light shielding blades
The shading device according to claim 1 or 2, wherein one thickness is different from the thickness of the other shading blades. 7. The shading device according to claim 6, wherein a shading blade having a larger outer shape than the other shading blades among the plurality of shading blades is made thinner than the other shading blades. . 8. The shading device according to claim 1, wherein the shading blades have the same weight. 9. The shading device according to claim 1, wherein the moments of inertia around the opening / closing operation centers of the respective shading blades are made equal to each other. 10. A shading device comprising a first shading blade and a second shading blade having a portion used for position detection and having an outer shape larger than that of the first shading blade, wherein a unit of the second shading blade The weight per area is the first
A light-shielding device, characterized in that the weight of the light-shielding blade is smaller than the weight per unit area. 11. The shading device according to claim 10, wherein the second shading blade is made of a material having a specific gravity smaller than that of the material of the first shading blade. 12. The shading device according to claim 10, wherein the first shading blade is made of a plated resin material, and the second shading blade is made of only a resin material. 13. The shading device according to claim 10, wherein the second shading blade is made thinner than the first shading blade. 14. The shading device according to claim 10, wherein the first and second shading blades have the same weight. 15. The shading device according to claim 10, wherein the moments of inertia about the opening / closing operation centers of the first and second shading blades are made equal to each other. 16. The shading device according to claim 10, wherein the position detection is performed using an optical sensor. 17. A light-shielding device comprising: a first light-shielding blade; and a second light-shielding blade having a portion for driving the first light-shielding blade and having an outer shape larger than that of the first light-shielding blade. The weight per unit area of the light-shielding blade is the first
A light-shielding device, characterized in that the weight of the light-shielding blade is smaller than the weight per unit area. 18. The shading device according to claim 17, wherein the second shading blade is made of a material having a specific gravity smaller than that of the material of the first shading blade. 19. The shading device according to claim 17, wherein the first shading blade is made of a plated resin material, and the second shading blade is made of a resin material only. 20. The shading device according to claim 17, wherein the second shading blade is made thinner than the first shading blade. 21. The shading device according to claim 17, wherein the weights of the first and second shading blades are equal. 22. The shading device according to claim 17, wherein the inertia moments about the opening / closing operation centers of the first and second shading blades are made equal to each other. 23. A camera comprising the light-shielding device according to any one of claims 1 to 22. 24. The camera according to claim 23, wherein the light shielding device is used as a shutter unit.