JP2002287207A - Shuttering device and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome the problem that a rotary shaft of a light shielding wing is difficult to close a centroid position due to restrictions of a lens or the like and the opening closing speed of the light shielding wing cannot be made foster. SOLUTION: In a shuttering device provided with a pair of shuttering wings 1 and 2, and driving means 5 for making these shuttering wings open/close driven, the above one pair of shuttering wings are respectively supported so as to permit open/close rotation around the same shaft 3, while this rotary shaft is arranged on the position being closer to the light axis from a driving means than drive power transmitting parts 5b, 1b and 2b of the pair of light shuttering wings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter device suitable for being incorporated in a camera.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 10, a shutter device called a lens shutter or the like is composed of a right light-shielding blade 121 that closes by turning right and a left light-shielding blade 122 that closes by turning left. Are formed.

The right light-shielding blade 121 and the left light-shielding blade 122
Can be opened and closed about the rotation shafts 121 a and 122 a, respectively, and can be elongated holes 121 b formed on the right light-shielding blade 121 and long holes 1 formed on the left light-shielding blade 122.
A drive pin 105b is engaged with 22b.

The drive pin 105b is moved (rotated) in the direction of arrow D by a drive motor (not shown). Thereby, the right light-shielding blade 121 turns right around the rotation axis 121a, the left light-shielding blade 122 turns left around the rotation axis 122a, and the left and right light-shielding blades 121, 122 turn from the open state to the closed state. An open-diameter hole 104k formed in a shutter base plate (not shown) is covered. Also, the drive pin 105
When b moves in the direction opposite to the direction of arrow D, the left and right light shielding blades 121 and 122 pivot from the closed state to the open state, and the open diameter hole 104k is opened.

[0005]

However, in the above-mentioned conventional shutter device, a pair of light-shielding blades are supported so as to be rotatable (rotatable) by respective dedicated rotation shafts.

On the other hand, since these light-shielding blades are rotationally driven by one drive pin, the trajectory of the drive pin passes on a line connecting the rotation axes of the respective light-shielding blades with the rotation axis of one of the light-shielding blades as the center. It must be arc-shaped.

On the other hand, in order to simplify the mechanism, the drive pin is generally a mechanism directly connected to a motor shaft which is a power source for driving the blades. For this reason, it is not possible to dispose the motor at the position where the lens is disposed.

Therefore, the motor must be arranged outside the lens, and the rotation axis of the light shielding blade must be arranged farther from the optical axis which is the center of the open diameter. For this reason,
There is a disadvantage that the distance from the rotation axis of the light-shielding blade to the center of gravity of the light-shielding blade increases, the moment of inertia of the light-shielding blade increases, and the closing speed of the blade decreases.

FIG. 11 is a side view of the conventional shutter device. An open hole 104k is formed at a position on the optical axis of the shutter base plate 104, and a drive pin 105b is provided on an output shaft 106c of the drive motor 106.
Are fixed so as to rotate integrally.

Reference numeral 108 denotes a blade cover plate, and its foot 1
08a is fixed to the shutter base plate 104. Also,
The right light shielding blade 121 and the left light shielding blade 122 are sandwiched between the shutter base plate 104 and the cover plate 108.

Reference numeral 121a denotes a rotation axis of the right light shielding blade 121. In FIG. 11, the rotation axis of the left light shielding blade 122 is 1
It is hidden behind 21a. 107 is a lens.

As shown in FIG. 11, the drive motor 6 cannot be arranged sufficiently close to the optical axis due to the restriction of the lens 107 in the lens barrel in which the shutter device is housed. For this reason, the rotation axis 121a is far from the optical axis. Accordingly, the distance from the rotation axis of the light shielding blade to the center of gravity of the light shielding blade becomes longer.

Accordingly, a first object of the present invention is to reduce the moment of inertia of the light-shielding blade by bringing the center of gravity of the light-shielding blade close to the rotation axis, thereby increasing the opening / closing speed of the light-shielding blade. It is intended to provide.

Further, a second object of the present invention is to provide a shutter device which, under the first object, prevents the driving source from being overloaded, especially at the start of the closing operation of the light shielding blade. The purpose is.

Further, a third object of the present invention is to provide the above-described first embodiment.
It is another object of the present invention to provide a shutter device capable of preventing a bounce at the end of a closing operation of a light shielding blade.

[0016]

In order to achieve the first object, according to a first aspect of the present invention, there is provided a shutter device having a pair of light-shielding blades and driving means for driving the light-shielding blades to open and close. The pair of light-shielding blades are supported so as to be able to open and close around the same rotation axis, and the rotation shaft is disposed at a position closer to the optical axis than a driving force transmitting portion from the driving means to the pair of light-shielding blades.

Accordingly, even in a case where the driving means must be arranged at a position distant from the optical axis due to a restriction by a lens or the like, the rotation center of the light-shielding blade and the center of gravity of the light-shielding blade are set to be different from the conventional one. It becomes possible to approach each other. Therefore, the moment of inertia at the time of opening and closing the light shielding blade can be reduced, and the light shielding blade can be rotated at a higher speed (that is, the time required for the opening or closing operation can be reduced).

Further, in order to achieve the second object,
In the second invention of the present application, the pair of light-shielding blades
When a cam portion that engages with the output pin of the driving means and generates an opening / closing force in accordance with the movement of the output pin is provided, the cam portion is gradually closed from the start of the closing operation of the light shielding blade ( (Incremental).

That is, the time required for closing the light-shielding blade is shortened by increasing the speed of closing the light-shielding blade gradually, instead of abruptly, for example, so as to have a sufficient speed in an intermediate state. At the same time, the drive source is prevented from being overloaded when the closing operation of the light shielding blade is started.

Further, in order to achieve the third object, in the third invention of the present application, the pair of light-shielding blades are respectively engaged with an output pin of a driving means so as to reduce an opening / closing force as the output pin moves. When the generated cam portion is provided, the cam portion is formed in a shape that reduces the closing speed near the end of the closing operation of the light shielding blade.

That is, instead of allowing the light-shielding blade to reach the closing position at a high speed, the speed of the light-shielding blade is reduced sufficiently to reach the closing position. This makes it possible to prevent the exposure from rebounding, and to suppress the occurrence of collision sound and improve the durability.

[0022]

(First Embodiment) FIG. 1 is an exploded view of a shutter device according to a first embodiment of the present invention. This shutter device is housed in a lens barrel of a so-called lens shutter camera.

FIG. 9 shows the structure of the camera. In FIG. 9, reference numeral 201 denotes a shutter device according to the present embodiment, which is mounted by being sandwiched between a lens group 202 and a lens group 203. Reference numeral 204 denotes an imaging / photoelectric conversion element. Reference numeral 205 denotes a shutter button.

In FIG. 1, reference numerals 1 and 2 denote a pair of light-shielding blades. Reference numeral 1 denotes a right light-shielding blade that closes by turning right (clockwise). It is a feather.

Reference numeral 1a denotes a rotary shaft hole formed in the right light-shielding blade 1, and 1b denotes a long cam hole (cam portion) formed in the right light-shielding blade 1.

Reference numeral 2a denotes a rotary shaft hole formed in the left light shielding blade 2, and 2b denotes a long cam hole (cam portion) formed in the left light shielding blade 2.

Reference numeral 4 denotes a shutter base plate, and an open hole 4k is formed at a position on the optical axis of the shutter base plate 4.

Reference numeral 3 denotes a shaft serving as a rotation center of the right light-shielding blade 1 and the left light-shielding blade 2, and is provided on the shutter base plate 4. The shaft 3 is fitted into the rotary shaft holes 1a and 2a of the right light shielding blade 1 and the left light shielding blade 2.

Reference numeral 4b denotes an elongated hole formed in the shutter base plate 4, which is formed at a position corresponding to the cam elongated holes 1b and 2b of the light shielding blades 1 and 2. Reference numeral 4c denotes a shaft hole formed in the shutter base plate 4.

Reference numeral 6 denotes a drive motor having an output shaft 6c.
A drive lever 5 having a drive pin 5b is fixed to the output shaft 6c so as to be integrally rotatable. The drive pin 5b penetrates the elongated hole 4b of the shutter base plate 4 and
Are engaged with the cam slots 1b and 2b. The tip of the output shaft 6c is fitted in the shaft hole 4c.

In the above configuration, when the photographer presses the shutter button of the camera, the drive motor 6 starts, and the drive lever 5 directly connected to the output shaft 6c rotates in the direction of arrow A in the figure.

Thus, the driving pin 5b and the cam slot 1
The right light-shielding blade 1 engaged and connected at b starts rotating in the direction of arrow B in the figure. On the other hand, the left light shielding blade 2 engaged and connected to the drive pin 5b by the long cam hole 2b starts rotating in the direction of arrow C in the figure. In this way, the right light shielding blade 1 and the left light shielding blade 2 close and move about the shaft (rotation axis) 3 like scissors, and cover the open diameter hole 4k.

The driving motor 6 rotates in the reverse direction, and the output shaft 6c
Is rotated in the direction opposite to the direction of arrow A, so that the drive pin 5b and the cam slot 1b,
The light shielding blades 1 and 2 engaged and connected at 2b rotate in the directions opposite to the directions of arrows B and C. In this way, the right light-shielding blade 1 and the left light-shielding blade 2 open like a pair of scissors about the axis (rotation axis) 3 to open the opening 4k.

FIG. 2 is a side view of the shutter device. Reference numeral 8 (not shown in FIG. 1) denotes a blade cover plate, which is fixed to the shutter base plate 4 at its foot 8a. The right light-shielding blade 1 and the left light-shielding blade 2 are sandwiched between a shutter base plate 4 and a blade cover plate 8. 7 is a lens.

According to the above-mentioned shutter device, as shown in FIG. 2, even if the drive motor 6 can only be arranged away from the optical axis due to the restriction of the lens 7, the shaft 3 (light-shielding blades 1, 2) can be used. Can be brought sufficiently close to the optical axis.

FIG. 3 shows the distance relationship between the center of gravity G of the light-shielding blade and the rotation axis, comparing the conventional case (A) and the present embodiment (B).

In FIG. 3A, Rj indicates the distance from the rotation axis 121a of the light shielding blade to the center of gravity G in the conventional case, and Rn indicates the distance from the rotation axis 3 of the light shielding blade to the center of gravity G in the present embodiment. Represents distance.

As is apparent from FIG. 3, Rn <Rj, and according to the present embodiment, the light-shielding blades 1,
The rotation shaft 3 can be made closer to the center of gravity G of the light-shielding blades 1 and 2, so that the moment of inertia of the light-shielding blades can be reduced. Therefore, the closing operation speed of the light shielding blades 1 and 2 can be increased.

FIG. 4 is an enlarged view of the cam slot 1b formed in the right light shielding blade 1. This cam slot 1b
Is a cam surface that comes into contact with the drive pin 5b during the closing operation and generates a closing force of the right light shielding blade 1 with the movement of the drive pin 5b, and is formed in an arc shape with a radius R. The inner surface of the elongated cam portion 1b is a cam surface that generates an opening force of the right light shielding blade 1 with the movement of the drive pin 5b during the opening operation, and is formed in an arc shape like the outer cam surface. Have been.

The cam slot 2b formed in the left shading blade 2 is formed in an arc shape having a slightly different curvature from the cam slot 1b in a direction opposite to the cam slot 1b. It is formed so that the angular velocity coincides with the right light shielding blade 1.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention.
The shape of a long cam hole 1b 'formed in the right light shielding blade 1' in the shutter device according to the embodiment is shown.

In the first embodiment, the cam surface of the long cam hole 1b 'in contact with the drive pin 5b has an arc shape with a radius R. In the present embodiment, the closing operation of the right light shielding blade 1' is started. The shape of the cam surface at the time of (initial closing) is an arc shape of a small curvature having a large radius Rs, and the right light-shielding blade 1 ′
The cam surface shape corresponding to the intermediate state and the end state of the closing operation is a large-curvature arc having a small radius Rm.

FIG. 6 shows the right light-shielding blade 1 'in this embodiment.
5 is a graph showing a relationship between the operating angle θ of the light shielding blade 1 ′ and the angular velocity ω of the right light shielding blade 1 ′.

The right light-shielding blade 1 starts to move at a small angular velocity at the initial stage of closing, reaches the maximum angular velocity in an intermediate state while gradually increasing the speed, and reaches a target operating angle (closed position).

By operating the light-shielding blades in this way, it is possible to prevent the drive motor from being overloaded at the initial stage of closing the light-shielding blades, as compared with the case where the closing operation is rapidly started at a high speed. It is possible to sufficiently draw out the speed of the drive motor. Moreover, the closing speed can be sufficiently increased by an intermediate state of the closing process of the light shielding blade,
The time from when the light-shielding blade starts to block the open diameter hole 4k until it is completely closed, that is, the closing time of the light-shielding blade can be shortened.

The cam slot (not shown) of the left shading blade has an arc opposite to the cam slot 1b and having a slightly different curvature, but the angular velocity with respect to the operating angle of the left shading blade is right shading. It is formed so as to match the blade.

(Third Embodiment) In the second embodiment,
Although the case where the angular velocity ω at the initial stage of closing the light-shielding blade is reduced has been described, when the light-shielding blade reaches the closing position at a high speed reached in the intermediate state of closing, the blade stopper (not shown) provided on the shutter base plate or the like is moved. There is a possibility that the light-shielding blades may bounce due to high-speed collision and re-exposure may be performed. Thus, in the present embodiment, the angular velocity ω of the blade at the end of the operation of the light-shielding blade is similarly reduced.

FIG. 7 shows an enlarged view of a cam slot 1b "formed on the right light-shielding blade 1" of the shutter device in this embodiment.

The cam surface of the cam slot 1b ", which corresponds to the start (close initial stage) of the closing operation of the right light-shielding blade 1", has a small curvature arc shape having a large radius Rs2. The cam surface shape corresponding to the intermediate state of the closing operation of the light-shielding blade 1 ″ is an arc of a large curvature having a small radius Rm2. Further, the cam surface shape corresponding to the end of the closing operation of the right light-shielding blade 1 ″ is changed. It has an arc shape with a small curvature and a large radius Re.

FIG. 8 shows the right light shielding blade 1 ″ in the case of this embodiment.
7 is a graph showing a relationship between the operating angle θ of the right light shielding blade 1 ″ and the angular velocity ω of the right light shielding blade 1 ″.

The right light-shielding blade 1 starts to move at a small angular velocity in the initial stage of closing, gradually increases in speed, reaches the highest angular velocity in the intermediate state, decelerates from the intermediate state, and has a small angular velocity near the end of closing. The desired operating angle (closed position) is reached.

As described above, by operating the light-shielding blade, it is possible to prevent an overload from being applied to the drive motor of the light-shielding blade at the initial stage of closing the light-shielding blade.
The speed in the intermediate state during the closing process of the light shielding blade can be increased, and the closing time of the light shielding blade can be shortened. Furthermore, since the speed of the light-shielding blade can be reduced near the end of closing, the impact force of the light-shielding blade against the blade stopper at the time of reaching the closing position is reduced, and re-exposure due to bouncing of the light-shielding blade is prevented. It is also possible to suppress the generation of collision noise and improve the durability.

The cam slot formed on the left shading blade has an arc opposite to the cam slot 1b and having a slightly different curvature. It is formed to match.

(Fourth Embodiment) In the first to third embodiments, the case has been described in which the cam slot of the light-shielding blade is constituted by one or a plurality of circular arcs. You may make it comprise by a part.

[0055]

As described above, according to the first aspect of the present invention, even if the driving means has to be arranged at a position distant from the optical axis due to the restriction by the lens or the like, the present invention is not limited to the conventional one. In comparison, the center of rotation of the light-shielding blade and the center of gravity of the light-shielding blade can be brought closer to each other. Therefore, the moment of inertia at the time of opening and closing the light-shielding blade can be reduced, and the light-shielding blade can be rotated at a higher speed (that is, the time required for the opening or closing operation can be reduced).

According to the second aspect of the present invention, the closing speed of the light shielding blade is not increased rapidly but is gradually increased from the start of the closing operation to the intermediate state. Can be prevented and the driving source is not overloaded when the closing operation of the light shielding blade is started.

Further, according to the third aspect of the present invention, it is possible to reach the closing position by sufficiently reducing the speed of the light-shielding blade instead of reaching the closing position at a high speed.
Even if it hits a stopper etc. provided in the closed position, the light-shielding blades can be prevented from bouncing and re-exposure is performed, and the occurrence of collision noise is suppressed and durability is improved. can do.

[Brief description of the drawings]

FIG. 1 is an exploded configuration diagram of a shutter device according to a first embodiment of the present invention.

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

FIG. 3 is a diagram illustrating the relationship between the center of rotation and the position of the center of gravity of the light-shielding blades in the conventional and the first embodiment of the shutter device.

FIG. 4 is a view showing a shape of a long hole of a light shielding blade in the shutter device of the first embodiment.

FIG. 5 is a view showing a shape of a long hole of a light shielding blade in a shutter device according to a second embodiment of the present invention.

FIG. 6 is a graph showing a relationship between an operating angle and an angular velocity of a light shielding blade in the second embodiment.

FIG. 7 is a view illustrating a shape of a long hole of a light shielding blade in a shutter device according to a third embodiment of the present invention.

FIG. 8 is a graph showing a relationship between an operating angle and an angular velocity of a light shielding blade in the third embodiment.

FIG. 9 is a sectional view of a camera provided with the shutter device.

FIG. 10 is a partial plan view illustrating a configuration of a light-shielding blade, a rotation shaft of the light-shielding blade, and a driving pin in a conventional shutter device.

FIG. 11 is a side view of a conventional shutter device.

[Explanation of symbols]

 1, 121, 2, 122 Light shielding blade 1a Rotating shaft hole 1b Cam long hole 3, 121a Rotating shaft 5b, 105b Drive pin 6, 106 Drive motor

Claims (7)

[Claims] 1. A shutter device having a pair of light-shielding blades and driving means for driving the light-shielding blades to open and close. A shutter device, wherein a shaft is arranged at a position closer to an optical axis than a driving force transmitting portion from the driving means to the pair of light shielding blades. 2. The light-shielding blades each have a cam portion that engages with an output pin of the driving means and generates an opening / closing force in accordance with the movement of the output pin. 2. The shutter device according to claim 1, wherein the shutter device has a shape that gradually increases the closing speed from the start of the closing operation of the blade. 3. 3. The light-shielding blades each have a cam portion that engages with an output pin of the driving means and generates an opening / closing force in accordance with the movement of the output pin. The shutter device according to claim 1, wherein the shutter device has a shape that reduces the closing speed near the end of the closing operation of the blade. 4. The shutter device according to claim 2, wherein the cam portion is constituted by a plurality of arc portions having different curvatures from each other. 5. The shutter device according to claim 2, wherein the cam portion includes a plurality of arc portions having different curvatures from each other and at least one straight portion. 6. The shutter device according to claim 2, wherein the cam portion is constituted by a plurality of linear portions. 7. A camera comprising the shutter device according to claim 1.