JPH07117681B2 - camera - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a structure of a lens barrel of a camera.

[Background of the Invention]

In the so-called varifocal type camera that switches the focal length of the taking lens by advancing the main optical system of the taking lens along the optical axis beyond the distance adjustment range and inserting the sub optical system on the optical axis. A diaphragm provided with a shutter on the optical axis between the optical system and the sub-optical system is already known, for example, as disclosed in JP-A-59-19926. However, in this known variable focus camera, a shutter base plate holding a shutter device is mounted on a rear base plate holding a sub optical system drive mechanism for inserting the sub optical system on the photographing optical axis. On the shutter base plate, a magnet holder equipped with an autofocus mechanism that extends the main optical system for distance adjustment and a shutter magnet is attached, and the front base plate is screwed onto the magnet holder. The cover enclosing all the drive mechanisms from the sub optical system to the main optical system is provided so as to project from the camera body. In the case where the lens barrel portion is formed by sequentially stacking the respective devices in this manner, for example, the shutter base plate is deformed during the assembling to easily deteriorate the shutter accuracy, and the dimensional deviation in the optical axis direction is prevented. Since the cover is formed to have a size that includes the auxiliary optical system holding frame located at the retracted position outside the photographing optical path, the external shape of the lens barrel portion becomes extremely large. It was.

On the other hand, in the variable focus camera, the amount of movement of the photographing optical system (particularly the main optical system) in the optical axis direction is extremely large, so that the amount of protrusion of the lens barrel portion with respect to the camera body becomes large.
However, the external shape of the lens barrel protruding from the camera body is
Considering handling, etc., it is desirable that the size be as small as possible. Therefore, a base plate that is movable along the optical axis is provided, and a sub-optical system driving device that is displaced at a right angle to the optical axis and requires a relatively large space is provided on the back side of the base plate together with the sub-optical system. Provided on the front side of the base plate is a shutter that also serves as an aperture, the main optical system, and a lens barrier that covers the front surface of the main optical system, and the lens shutter is constructed by enclosing the aperture and shutter from the lens barrier with a cylindrical outer cylinder. If the sub-optical system and the base plate are left and only the lens barrel portion of the camera body protrudes from the camera body when the focal length is switched, the camera can be downsized and the handling becomes easy.

However, in the above-mentioned configuration, as in the above-described known example, the method of sequentially stacking the respective subassemblies has a drawback that it is difficult to obtain accuracy and weak against external force.

[Object of the Invention]

The present invention solves the above-mentioned drawbacks of conventional cameras, is compact in spite of having a built-in lens barrier, has a small amount of protrusion from the camera body, and has a negative effect on the photographing optical system and the shutter device even when external force is applied. An object of the present invention is to provide a varifocal camera having a lens barrel that is not likely to be given.

[Outline of Invention]

In order to achieve the above object, the present invention provides a support member movable in the shooting optical axis direction by electric drive, a shooting optical system,
A shutter unit, an outer cylinder that covers an outer periphery of the photographing optical system and the shutter unit are arranged, and a fixing unit that fixes the shutter unit to the subject side of the support member without the outer cylinder interposed. Is the technical point.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view of a camera according to an embodiment of the present invention, showing a state in which a main optical system is extended and a sub optical system is inserted on a photographing optical axis, and FIG. 2 is a lens barrel portion in FIG. 3 is an exploded perspective view showing the configuration of FIG.

In FIG. 1, the taking lens includes a main optical system 1 and a sub optical system 2.
And a main optical system holding frame 3 for holding the main optical system 1.
Is fixed to the shutter base plate 5 that holds the shutter 4 that also serves as the diaphragm. The shutter base plate 5 is attached to the surface of a base plate 6 that can be moved back and forth in the optical axis direction by machine screws 7. Further, a barrier unit 8 is provided on the surface of the base plate 6 so as to be sandwiched between the outer cylinder 9 and the base plate 6, and the barrier unit 8 and the outer cylinder 9 are fixed by machine screws 10.
Are fixed on the base plate 6. The barrier unit 8
Consists of a rear ring 8A having three legs 8a, a front ring 8B attached to the rear ring 8A at a predetermined interval, and a lens barrier 8C provided between the two so as to be openable and closable. Protrusions 8b are provided on the tips of the legs 8a, and the protrusions 8b are
As shown in the drawing, the three bosses 6a formed so as to project from the surface of the base plate 6 are fitted in the notch grooves 6b provided on the side surfaces.

The shutter base plate 5 is provided with an escape groove 5a at a portion corresponding to the boss 6a of the base plate 6, and the escape groove 5a is formed outside the operation locus of the shutter blades of the diaphragm / shutter 4. The outer shape of the shutter base plate 5 is formed in a slightly smaller circular shape due to the inner diameter of the cylindrical outer cylinder 9 (see FIG. 2).

As shown in FIG. 3, the sub optical system 2 is held by a sub optical system holding frame 11 that is swingably provided along the back surface of the base plate 6, and the sub optical system holding frame 11 is the back surface of the base plate 6. When the main optical system 1 is moved in the optical axis direction beyond the distance adjustment range by being driven by the sub optical system switching mechanism 12 driven by the reversible motor M provided in It is configured to be inserted on the axis or displaced to a retracted position outside the optical axis shown by a chain double-dashed line in FIG. Further base plate 6
A feed screw shaft 14 for moving the base plate 6 in the optical axis direction penetrates through the feeding mechanism 13 driven by a motor M, and a guide shaft 15 for guiding the forward / backward movement.
16 also penetrates as shown in FIG. The feed screw shaft 14 and the guide shafts 15 and 16 are all fixed between the camera body 17 and the dark box 18 shown in FIG. The outer circumference of the outer cylinder 9 that is movable in the optical axis direction integrally with the base plate 6 is fitted into a dark box 18 fixed to the camera body 17, and the outer circumference of the camera body 17 and the dark box 18 is covered with an exterior cover 19. It is covered by.

Since the embodiment of FIG. 1 is configured as described above, the shutter unit including the shutter 4 also serving as the diaphragm and the shutter base plate 5 is configured so that the escape groove 5a of the shutter base plate 5 does not contact the boss 6a of the base plate 6. It is placed on the surface of the base plate 5 and attached to the base plate 6 by machine screws 7. The main optical system holding frame 3 that holds the main optical system 1 is fixedly mounted on the shutter base plate 5, and in that case, the central cylindrical portion of the shutter base plate 5 to which the main optical system holding frame 3 is attached is in the optical axis direction. Since the shutter base plate 5 is thick, the shutter base plate 5 is not likely to be deformed, and therefore the shutter precision is not affected by the mounting of the main optical system 1.

Next, the barrier unit 8 including the rear ring 8A, the front ring 8B and the lens barrier 8C is attached to the base plate 6. At that time, rear ring
The legs 8a of 8A never touch the shutter base plate 5 and the main optical system holding frame 3. Therefore, even if an external force is applied to the barrier unit 8, there is no fear that the shutter accuracy will be affected. Rear ring
The tip of the leg 8a of 8A and the boss 6a of the base plate 6 are coupled to each other so that the protrusion 8b provided at the end of the leg 8a is inserted into the notch groove 6b provided in the boss 6a on the base plate 6 without backlash. Done by. After that, the outer cylinder 9 is put on the outer periphery of the barrier unit 8 and fixed to the base plate 6 with machine screws 10, whereby the assembling work on the front surface side of the base plate 6 is completed. When the barrier unit 8 is fixed to the base plate 6, since the outer peripheral surface of the leg 8a fits on the inner peripheral surface of the outer cylinder 9, the radial movement of the leg 8a about the optical axis is caused by the outer cylinder 9. Suppressed. Also barrier unit 8
The movement in the direction of the optical axis is suppressed by the front end edge 9a of the outer cylinder 9 pressing the front ring 8B and the tips of the legs 8a being pressed against the end surface of the boss 6a. Therefore, the base plate 6 of the barrier unit 8
It does not require a small screw or the like for fixing to, and the assembly work can be performed quickly and easily.

On the other hand, an optical system driving device 12, 13 including a sub optical system holding frame for holding the sub optical system 2 and the reversible motor M, which requires a large space, is attached to the back surface of the base plate 6. Therefore, these assembling operations can be performed independently of the attaching operation of the main optical system 1 provided on the front surface of the base plate, the shutter unit including the shutter base plate 5, the barrier unit 8 and the like, and the work efficiency is improved. Can be made.

In the above embodiment, the movement of the base plate 6 in the optical axis direction and the swing of the auxiliary optical system holding frame 11 are configured to be performed by a reversible motor, but the base plate is manually moved. The sub optical system may be inserted and removed on the optical axis in conjunction with this movement.

〔The invention's effect〕

As described above, according to the present invention, the supporting member movable in the photographing optical axis direction is provided with the photographing optical system, the shutter unit, and the outer cylinder covering the outer circumferences of the photographing optical system and the shutter unit. Since the shutter unit has fixing means for fixing the shutter unit to the subject side of the support member without the intervention of the outer cylinder, even if an external force is applied to the outer cylinder which can be touched by the user of the camera, the shutter unit is not attached to the shutter unit. It is not transmitted directly. Therefore, the accuracy of the shutter unit is not affected. Further, since the outer cylinder and the shutter unit are separately and independently fixed to the support member, there is an advantage that the outer cylinder has a small outer shape and is compact, and the assembly is quick and easy.

Further, since the shutter unit is fixed to the subject side of the supporting member, the non-subject side (film surface side) of the supporting member may be
The auxiliary optical system, the electric drive mechanism of the support member, and the like can be arranged, and it is not necessary to arrange these drive mechanisms and the like on the subject side of the support member. As a result, the outer shape of the outer cylinder can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG.
FIG. 3 is an exploded perspective view showing the configuration of the lens barrel portion of the figure, and FIG. 3 is a perspective view of the base plate of FIG. 1 seen from the back side. [Explanation of Signs of Main Parts] 1 ... Main optical system, 2 ... Sub optical system, 3 Main optical system holding frame,
4 ... Shutter that also serves as aperture (shutter unit), 5 ...
Shutter base plate (shutter unit), 6 ... Base plate, 6a ...
… Boss, 8A …… Rear ring (8 …… Barrier unit), 8B ……
Front ring (8 ... barrier unit), 8C ... lens barrier (8 ... barrier unit), 9 ... outer cylinder, 11 ... sub-optical system holding frame, 12 ... optical system switching mechanism.

Claims (1)

[Claims] 1. A photographic optical system, a shutter unit, and an outer cylinder that covers the outer periphery of the photographic optical system and the shutter unit are provided on a support member that is movable in the photographic optical axis direction by electric drive. A camera having a fixing means for fixing the shutter unit to the subject side of the support member without interposing the outer cylinder.