JPH07114059A - Shutter device - Google Patents

Abstract

PURPOSE:To arrange the front and rear group lenses of a zoom lens closely to each other for instance and to make a zooming range on a wide-angle side large by fixing a motor projected from a pedestal toward the top end part of a movable lens barrel. CONSTITUTION:This shutter device is composed of the pedestal 10, a shutter driving ring 11, shutter blades 12-14 and a coreless motor 26 and fixed on the rear end side of the movable lens barrel. On the pedestal 10, an aperture for exposing 16 is formed on the center part. The shutter driving ring 11 is assembled between the aperture 16 and the periphery, freely turnably supported centering an optical axis and turned by the drive of the motor 26. The aperture 16 is opened/closed by three shutter blades 12-14 by the turn of the shutter driving ring 11. The motor 26 has the shape of a column whose outside diameter is smaller than the width between the aperture 16 and periphery of the pedestal 10 and fixed thereon so as to project in parallel with the optical axis from the pedestal 10 to the top end part of the movable lens barrel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter device,
More specifically, the present invention relates to a shutter device that opens and closes shutter blades by driving a coreless motor.

[0002]

2. Description of the Related Art Compact cameras, which can easily take pictures by simply pressing a shutter, are becoming more diverse and multifunctional year by year.
Above all, the growth of zoom cameras is remarkable, and they are already the mainstream of compact cameras. With this zoom camera, it is ideal to use the
The lens shutter is used. This type of shutter generally opens and closes the exposure opening with three to five shutter blades, and the opening and closing is performed by a stepping motor, an iris motor, or the like. Since the stepping motor, the iris motor, and the like can easily have a thin shape, it is possible to reduce the thickness of the shutter device.

However, if a stepping motor, an iris motor, or the like is used to drive the shutter blades, the control program for driving them becomes complicated, and it is difficult to obtain a sufficient torque required to drive the shutter blades. There are difficulties, and the use of a DC motor is being considered. In particular, when a coreless motor is used, it is preferable because the starting characteristic and response are good and the inertia is small.

[0004]

By the way, since the outer diameter of the coreless motor has an elongated cylindrical shape, it is difficult to incorporate it in the lens barrel, and a camera using this is irrespective of the above-mentioned characteristics. Then, there was a drawback that the compactness was impaired.

The present invention has been made in order to solve the above-mentioned problems, and a shutter which can be efficiently incorporated into a movable lens barrel while using an elongated cylindrical motor for driving shutter blades. The purpose is to provide a device.

[0006]

In order to solve the above problems, according to the invention of claim 1, a cylindrical coreless motor provided for driving the shutter blades of the shutter device is projected toward the front lens group. It is arranged to do.
According to this, since the coreless motor is used, the rising characteristics and response when driving the shutter blades are good, and the inertia is small, which is preferable. Also, since the outer diameter of the coreless motor is an elongated cylindrical shape, a gear fixed to the drive shaft on one end side meshes with the drive gear of the shutter blades so that the longitudinal direction of the motor is parallel to the optical axis. When incorporated in the device, the other end of the motor largely projects from the shutter device. For example, when a shutter device is incorporated in a two-group zoom lens, it is generally incorporated at the rear end of a movable lens barrel holding a front lens group, but when the other end of the motor is directed toward the rear lens group side, Therefore, it becomes impossible to bring the rear lens group close to each other, and the zoom range is greatly limited particularly on the wide angle side. For this reason, since the coreless motor is arranged so as to project toward the front lens group, it is possible to arrange the front lens group and the rear lens group with a small interval.

According to the invention described in claim 2,
A ring-shaped pedestal member having an opening for exposure formed in the central portion, a shutter drive ring incorporated between the opening and the outer edge of the pedestal member, and supported rotatably around the optical axis, respectively. An end portion of which is pivotally attached to the pedestal member,
At least two pieces that are movable in a range from a closed position that shields the opening in association with the rotation of the shutter drive ring to a fully open position that exposes the opening without each tip protruding from the outer edge of the pedestal member. A shutter blade and a motor for rotating the shutter drive ring, having a cylindrical shape whose outer diameter is equal to or less than the width of the opening and the outer edge of the pedestal member, and is directed from the pedestal member toward the tip of the movable lens barrel. The motor is held by the pedestal member so as to project in parallel with the optical axis.

By the way, there is a possibility that the angle of view of the photographing lens may be obscured at the wide angle due to the protruding contour shape of the motor. Therefore, in the invention of claim 3, the shutter drive ring is arranged within the length of the motor, and a gear train for transmitting the drive of the motor to the shutter drive ring is provided between the outer edge of the pedestal member and the opening. They are arranged in a line within the width of the space. According to this, since the shutter drive ring is arranged within the length of the motor, the protruding length of the motor can be reduced.

Further, in the invention according to the fourth aspect, a concave portion which is inserted into the optical axis side is provided on the outer edge of the shutter blade, and when the shutter blade is rotated to the fully open position, the concave portion and the outer edge of the pedestal member are provided. The gear fixed to the drive shaft of the motor is located in the gap formed in the. According to this, the gear fixed to the rotation shaft of the motor is arranged in the gap formed between the recess and the outer edge of the pedestal member when the shutter blade is rotated to the fully open position. The length protruding from the base member can be further reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a shutter device 9 is a program shutter that also serves as a diaphragm, and has an annular pedestal 1
0, shutter drive ring 11, three shutter blades 12
To 14 and the pressing plate 15. The pedestal 10 has an opening 16 in the center, and thickened restricting portions 17 and 18 are formed on the inner and outer peripheral portions. A ring groove 19 that rotatably receives the shutter drive ring 11 is provided between the restricting portions 17 and 18. Further, three restriction plates 20 to 22 for preventing the shutter drive ring 11 from coming off are formed on the restriction part 17 on the inner peripheral part.

Supporting pins 23 to 2 for rotatably supporting the three shutter blades 12 to 14 are provided on the restricting portion 18 on the outer peripheral portion.
5 are planted at a predetermined pitch. Support pins 23,
The coreless DC motor 26
A gear train 27 for transmitting the drive of the above to the shutter drive ring 11 is arranged. Each of the gears 28 to 32 constituting the gear train 27 has a rotation shaft formed on a surface recessed from the regulation portion 18 by one step, and protrudes into the regulation portion 18 when the gear trains 27 are rotatably fitted. It is arranged not to.

The shutter drive ring 11 is formed with three cutouts 33 to 35 on the inner circumference thereof for receiving the control projections 20 to 23, respectively, and these cutouts 33 to 35 are controlled projections 20 to 22. It is attached so as to be rotatable around the restricting portion 17 by being inserted according to. The shutter drive ring 11 has a gear portion 36 integrally formed on a part of its outer periphery meshed with the gear 32 of the gear train 27, and is rotated according to the drive of the motor 26.
This rotation is performed within the range between the restriction protrusions 20 and 21. Further, the shutter drive ring 11 has a drive pin 3 for opening and closing each of the shutter blades 12 to 13.
7 to 39 are planted at a predetermined pitch. Further, on the outer circumference of the shutter drive ring 11, a piece 40 having an encoded pattern 66 printed on a part thereof is integrally formed.
Since the encode pattern 66 is printed on the piece 40, the cost can be reduced as compared with the conventional case where the encode pattern is formed by making a hole, and a fine pattern can be easily printed. There is an advantage that various controls can be performed.

The shutter blades 12 to 14 have the same shape, and end portions 44 to 46 in which holes 41 to 43 for inserting the support pins 23 to 25 are formed, and the opening 1 respectively.
It is composed of vanes 47 to 49 for closing 6. At the outer edge between the end portions 44 to 46 and the blade portions 47 to 49, recessed portions 50 to 52 are formed which are recessed one step toward the optical axis. The drive pin 3 is provided near the recesses 50 to 52.
Slots 53 to 55 that are inserted through 7 to 39 are formed. These slots 53 to 55 are driven by drive pins 37 to 39 in order to reduce the change in exposure as the diameter of the opening formed by the shutter blades 12 to 14 at the time of opening is reduced.
The shape is bent in a direction close to the rotation locus of the.

The pedestal 10 has an outer diameter contour of the pedestal 10, blade portions 47 to 49 and end portions 44 to of the shutter blades 12 to 14.
Utilizing the gap formed between the pressing plate 46 and
Three mounting bases 57 to 59 for mounting 5 are formed. The pressing plate 15 is formed with an opening 60 having the same diameter as the opening 16, for example.
60 will determine the diameter of the maximum opening. The maximum aperture diameter is determined according to the F value of the optical system arranged in front, and the overall outer diameter including the pedestal 10 is determined according to the outer diameter of the lens barrel. The shutter drive ring 1
It is desirable that the width of 1 is as small as possible in order to make the entire shutter device compact.

The shutter blades 12 to 14 are superposed on each other.
It is as shown in FIG. That is, the shutter blade 12 is located at the lowest position in sliding contact with the regulating portion 17, the shutter blade 13 is superposed on it, and the shutter blade 1 is arranged at the uppermost position.
4 is located. When the shutter blades 12 are fully opened, the opening 16 is exposed, and the outer edges of the shutter blades 12 to 14 do not protrude from the outer peripheral edge of the pedestal 10, and the blade portions of the shutter blades 12 to 14 are prevented to prevent biting. 47 to 49 are in sliding contact with different end portions 44 to 46 of the shutter blade.

Two ribs 62, 63 having a half-moon-shaped cross section are formed on the surface of the pedestal 10 on the side opposite to the restricting portions 17, 18 on the front side of the optical system so as to press-fit and adhere the motor 26. There is. Further, below the pedestal 10, the through hole 6
4 are formed. A reflective photosensor 65 is attached inside the through hole 64. The photo sensor 65 reads the encode pattern 66 and causes a microcomputer incorporated in the camera body to monitor the rotation amount of the shutter drive ring 11. The microcomputer controls the drive of the motor 26 according to the drive program, and reverses the rotation of the motor 26 when a predetermined rotation amount is reached. Note that the motor 26 is usually controlled so that the shutter blades 12 to 14 close the opening 16. Further, a part of the ring groove 19 is cut out in order to allow the rotation of the piece 40 of the shutter drive ring 11.

As shown in FIG. 3, the shaft of the motor 26 is
The drive gear 68 is fixed. And the ribs 62, 6
When the motor 26 is inserted into the gear 3, it meshes with the gear 28 of the gear train 27. The gear trains 27 are arranged in a line between the drive gear 68 and the gear portion 36 of the shutter drive ring 11 and within the range of the restriction portion 18. The path immediately above the drive gear 68 and the gear train 27 is the movement path of the shutter blades 14. For this reason,
A motor 26 protruding from the pedestal 10 toward the front optical system
The contour length of can be made as short as possible. In addition,
Each gear 28-32 of the gear train 27 is provided with a mini chair bearing. Since the inner rings of these bearings are press-fitted into the shafts, the gears 28 to 32 are prevented from entering the movement path of the shutter blades 14.

Such a shutter device 9 is built in a lens barrel of a zoom lens as shown in FIG. This zoom lens is a two-group zoom lens including front group and rear group lenses 70 and 71, and a cam barrel 7 in which a cam groove 72 is formed.
By rotating 3 by driving the zoom motor 74, the movable barrel 76 incorporating the front lens group frame 75 moves back and forth in the direction of the optical axis 77 in response to the displacement of the cam groove 72, and also the rear lens group frame. 78 moves forward and backward in the direction of the optical axis 77 inside the cam barrel 73 according to the helicoid lead. The rear lens group 7
1 moves forward and backward in the direction of the optical axis 77 inside the rear lens group frame 78 by driving a focusing motor (not shown) during focusing.

Inside the movable barrel 76 and in the front lens group 70.
The shutter device 9 according to the present invention is mounted between the rear lens group 71 and the rear lens group 71. The coreless DC motor 26 used in the shutter device 9 has a contour length of about 15 to 16 mm, which is shorter than the coreless motor used in a pager or the like, and the contour of the motor 26 protruding from the pedestal 10. It is attached with the length thereof facing the front lens group 70. Further, the output torque of the motor 26 is very small, 0.3 gcm, and if the rotation speed of the output shaft is set to 2000 to 3000 rpm, even if the torque is small, the gear train 27 has a reduction ratio of 1/4 to 1/5. The rotational force is transmitted to the shutter drive ring 11 after being decelerated by, but in an experiment, the shutter blades 12 to 14
Was found to be sufficient to drive. Therefore, in FIG.
As shown in FIG.
The motor 26 that projects from the pedestal 10
Since the contour length of the lens is as short as possible, the lens barrel does not increase in size, and the angle of view of the taking lens at wide angle can be widened.

Next, the operation of the shutter device will be briefly described. The shutter device 9 is normally in a state in which the opening 16 is closed by the shutter blades 12 to 14, as shown in FIG. When the shutter button is half-pressed by the photographer, the microcomputer performs photometry and distance measurement, and when the shutter button is fully pressed by the photographer, the zoom lens is extended and focused. After that, the coreless DC motor 26 is driven in the forward direction according to the drive program. As a result, the drive of the motor 26 is transmitted to the shutter drive ring 11 via the gear train 27, and the shutter drive ring 11 rotates in the clockwise direction shown in FIG. This causes the shutter blades 12 to 14 to rotate counterclockwise about the support pins 23 to 25, and the blade portions 47 to 4 on the optical axis 77.
An opening 9 is formed, and the subject light is incident on the film through this opening.

The microcomputer includes a photo sensor 6
The rotation amount of the shutter drive ring 11 is monitored via the motor 5, and when the rotation amount according to the photometric value is reached, the motor 26
Rotate in reverse. The reverse rotation of the motor 26 causes the shutter drive ring 11 to rotate counterclockwise, and this rotation causes the shutter blades 12 to 14 to rotate clockwise about the support pins 23 to 25, respectively.
The opening 16 is closed with. The film is exposed by the amount of light that has passed while the shutter blades 12 to 14 were open.

FIG. 6 shows a state where the shutter blades 12 to 14 are fully opened. At this time, the subject light is regulated not by the openings formed by the shutter blades 12 to 14 but by the openings 16 and 60 provided in the pedestal 11 or the pressing plate 15. 5 and 6, the pressing plate 15 is omitted in order to prevent the drawings from becoming complicated.

In the above embodiment, the movement path of the shutter blades 14 is provided on the axis of the motor 26, but the present invention is not limited to this, and the outer diameter contour of the pedestal 10 and the shutter blades are fully opened. The drive gear 68 of the motor 26 may be disposed here by utilizing the space generated between the recessed portions 50 to 52 of 12 to 14. According to this, the protrusion amount of the motor 26 is shortened by the space for moving the shutter blades 12 to 14 described in the above embodiment, and it is possible to further widen the angle of view of the taking lens at wide angle. Further, in the above embodiment, the shutter device 9 is used as the zoom camera, but the present invention is not limited to this, and the shutter device 9 may be used for a single focus type camera.
Further, in the above-described embodiment, the number of shatter blades is three, but the present invention is not limited to this, and the number of shutter blades may be increased in order to reduce the rotation amount of the shutter drive ring 11. Needless to say, two shutter blades can be applied.

[0024]

As described in detail above, according to the present invention, since the coreless motor is used, the rising characteristics and responsiveness when driving the shutter blade are good, and the inertia is small, which is preferable. Further, since the coreless motor is arranged so as to project in the direction of the front lens group, the distance between the front lens group and the rear lens group can be shortened and the zoom range on the wide angle side can be increased. According to the second aspect of the invention, the motor for rotating the shutter drive ring is housed in an outer diameter not larger than the width between the opening and the outer edge of the pedestal member and directed from the pedestal member to the tip of the movable lens barrel. Since it is held by the pedestal member so as to project in parallel with the optical axis, it is possible to efficiently install the movable lens barrel in the movable lens barrel while using a motor having an elongated cylindrical shape for driving the shutter blades. Further, according to the third aspect of the invention, since the shutter drive ring is arranged within the length of the motor, it is possible to reduce the protruding length of the motor, and it is possible to achieve compactness. Further, in the invention according to claim 4, since the gear fixed to the rotating shaft of the motor is arranged in the gap formed between the concave portion and the outer edge of the pedestal member when the shutter blade is fully opened, the pedestal member is provided. Therefore, the length by which the motor projects is further reduced, and the angle of view of the taking lens can be made wider.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a shutter device of the present invention.

FIG. 2 is a cross-sectional view of a shutter device.

FIG. 3 is a sectional view of a main part of a gear train.

FIG. 4 is a cross-sectional view of a zoom lens using a shutter device.

FIG. 5 is an explanatory diagram showing a shutter device at the time of closing.

FIG. 6 is an explanatory diagram showing a shutter device when fully opened.

[Explanation of symbols]

 9 shutter device 10 pedestal 11 shutter device 12 to 14 shutter blades 15 pressing plate 26 coreless DC motor 27 gear train 68 drive gear

Claims (4)

[Claims] 1. A shutter device, which is used in a two-group zoom lens for moving a movable barrel supporting a front lens group and a rear lens group in the optical axis direction and fixed to the rear end side of the movable barrel, wherein A shutter device, wherein a cylindrical coreless motor for driving shutter blades is arranged in the device so as to project toward the front lens group. 2. A shutter device fixed to a rear end portion of a movable lens barrel, wherein a ring-shaped pedestal member having an exposure opening formed in a central portion, and the pedestal member is incorporated between the opening and the outer edge of the pedestal member. A shutter drive ring that is rotatably supported about the optical axis, and each end of the shutter drive ring is rotatably attached to the pedestal member.
At least two pieces that are movable in a range from a closed position that shields the opening in association with the rotation of the shutter drive ring to a fully open position that exposes the opening without each tip protruding from the outer edge of the pedestal member. A shutter blade and a motor for rotating the shutter drive ring, having a cylindrical shape whose outer diameter is equal to or less than the width of the opening and the outer edge of the pedestal member, and is directed from the pedestal member toward the tip of the movable lens barrel. A shutter device comprising: a motor held by the pedestal member so as to project in parallel with an optical axis. 3. The shutter drive ring is arranged within the length of the motor, and a gear train for transmitting the drive of the motor to the shutter drive ring is arranged in a line within the width between the outer edge of the pedestal member and the opening. 3. The shutter device according to claim 2, wherein the shutter device is arranged in. 4. A recess is formed on the outer edge of the shutter blade so as to enter the optical axis side, and the motor is provided in a gap formed between the recess and the outer edge of the pedestal member when the shutter blade is rotated to the fully open position. The shutter device according to claim 2 or 3, wherein a gear fixed to the drive shaft of is located.