JPH0755546Y2 - Zoom lens with barrier device - Google Patents

Description

[Technical Field] The present invention relates to a zoom lens, and more particularly to a zoom lens with a barrier device that includes a lens barrel and a barrier device that can significantly reduce the storage length.

“Prior Art and Its Problems” Recently, demands for miniaturization of cameras have been extremely strong, and the width and the height have reached a limit which is limited by the size of the film and the aperture. However, the thickness was limited by the lens storage length. The shorter the storage length, the greater the amount of movement of the lens group,
It requires a long cam ring. Therefore, when the balance between the amount of movement of this lens group and the length of the cam ring is lost, the lens retracts, but the cam ring protrudes, the overall length does not shorten, and the thickness of the camera does not become thin. The inconvenience occurs.

Furthermore, if a lens barrier that protects the lens is built in, the inconvenience that the storage length of the lens becomes longer and the barrier opening / closing device becomes complicated accordingly.

[Purpose of Invention] The present invention provides a lens barrel that can reduce the thickness of a zoom lens when the lens is housed, and a barrier device can be used without increasing the length of the lens barrel when housed.
The purpose is to obtain with a simple structure.

[Outline of the Invention] In the conventional lens barrel according to the present invention, a cam ring that rotates at a fixed position moves the lens between a shooting position including a macro area and a zooming area and a storage position. The inventors discovered the fact that it hinders the reduction in thickness, solved this problem, and arrived at the present invention.

The present invention includes a fixed barrel fixed to the camera body,
A lens guide barrel that moves back and forth in the optical axis direction with respect to the fixed barrel, at least a front lens group that is guided by the lens guide barrel so as to be movable in the optical axis direction, and the lens guide barrel together with the front lens group. A zoom lens having a lens cover tube that is movably guided in the optical axis direction, the lens cover tube moving to a storage position and a shooting position capable of zooming, and a plane orthogonal to the optical axis on the lens cover tube. A barrier rotatably supported therein for opening and closing a photographing opening of the zoom lens; and a ring member for rotating and opening and closing the barrier by rotating in a plane orthogonal to the optical axis about the optical axis. A barrier opening / closing mechanism having a interlocking member for rotating the ring member when the lens cover cylinder moves between the photographing position and the storage position is provided.

According to this configuration, the cam ring and the lens guide ring that rotate relative to each other move forward and backward in the optical axis direction while holding the movable lens, and the relative rotation of both moves the movable lens in the optical axis direction. Even if the length of the ring is short, the moving distance of the moving lens can be increased, so that the length of the lens barrel during storage can be shortened, and the barrier rotates in the plane orthogonal to the optical axis. Since the lens cover cylinder and the lens guide ring are opened and closed in association with relative movement, the barrier device having a simple structure can be obtained without increasing the length of the lens barrel.

"Embodiment of the Invention" The present invention will be described below with reference to illustrated embodiments. The illustrated embodiment shows an embodiment of a zoom lens with a barrier device according to the present invention. Fig. 1 is an exploded perspective view of the zoom lens, and Figs. 2 and 3 show a retracted position and a wide end position, respectively. FIG. 6 is an end view showing a portion other than a lens guide ring in a vertical section.

A fixed barrel is attached to the camera body 11 of the lens shutter type camera.
12 is fixed. Reference numerals 13 and 14 denote outer rails and inner rails formed on the camera body 11 as film guides, and the rails 13 and 14 form a film holding surface. According to the present embodiment, the front and rear two groups of moving lenses 1
Can store 5 and 16 by retracting them to a state where they are extremely close to the film holding surface, and since the annular member such as the cam ring is also short, the storage length is short.

An outer helicoid ring 18 having helicoid peaks formed on the inner circumference is fixed in the fixed cylinder 12 via fixing screws 19. The outer helicoid ring 18 has a helicoid peak 20a on the outer periphery.
The inner helicoid ring 20 in which is formed is screwed, and a cam ring 22 is fixed in the inner helicoid ring 20 via a fixing screw 21 (see FIG. 4).

On the outer circumference of the inner helicoid ring 20, as shown in FIG.
Gear 20b having ridges (in the optical axis direction) extending parallel to the optical axis
Are formed in the same direction as the lead angle of the helicolid crest 20a. The inner helicoid ring 20 is rotationally driven in the forward and reverse directions via a pinion 27a meshing with the gear 20b and a motor 27 that rotationally drives the pinion 27a. Therefore, the cam ring 22 is
When the inner helicoid ring 20 is driven to rotate, the helicoid mountain
It moves along the optical axis according to the lead of 20a.

A lens guide ring 24 is fitted in the cam ring 22 so as to move integrally in the optical axis direction and be relatively rotatable.
A straight guide plate 26 is fixed to the rear end of the lens guide ring 24 with a fixing screw 25. This straight guide plate 26
The projecting portion 26a protruding from the outer periphery thereof is engaged with the lens guide ring guide groove 12a formed on the inner surface of the fixed barrel 12. The lens guide ring guide groove 12a is a linear groove in the optical axis direction in this embodiment.

An inner flange 29 formed at the rear end of the cam ring 22 is fitted in an annular groove 28 formed between the rear end of the lens guide ring 24 and the linear guide plate 26 so as to be relatively rotatable. . Therefore, although the lens guide ring 24 is restricted from rotating by the lens guide ring guide groove 12a, the lens guide ring 24 always moves integrally with the cam ring 22 in the optical axis direction, and the cam ring 22 moves relative to the lens guide ring 24. Can be rotated.

The front and rear two groups of movable lenses 15 and 16 are respectively fixed to a front group lens frame 30 and a rear group lens frame 31 located inside the lens guide ring 24. The front lens group frame 30 is a shutter block.
The helicoid ring 33 fixed to 32 is helicoid-bonded. The shutter block 32 is fixed to the front group moving frame 34, and at least three shutter blocks are provided on the outer peripheral portion of the front group moving frame 34.
Book guide pins 35 are provided. Similarly, at least three guide pins 36 are provided on the outer periphery of the rear lens group frame 31. The guide pins 35, 36 are overlapped in FIGS. 2 and 4.

As is well known, the shutter block 32 rotates the drive pin 32a by an angle corresponding to the distance signal from the distance measuring device to the subject, and the front group lens frame 30 is interlocked via the drive pin 32a and the pin 30a. Are rotated together and moved along the helicoid in the optical axis direction to adjust the focus. Further, the shutter blade 32b is operated according to the brightness signal of the subject.

A lens cover cylinder 38 is fitted on the outer side of the shutter block 32 and is fixed to the front group moving frame 34. Reference numeral 39 is a decorative cylinder that covers the outer circumferences of the lens guide ring 24 and the cam ring 22 projecting from the main body outer casing 11a. The decorative case 39 is omitted in FIG.

The cam ring 22 has a front group cam groove 22a and a rear group cam groove 22b, through which the guide pins 35 and 36 are inserted, respectively. The lens guide ring 24 has lens guide grooves 24a, 24a corresponding to the front group cam grooves 22a and the rear group cam grooves 22b, respectively.
b is drilled. In this embodiment, the lens guide groove 2
Both 4a and 24b are linear grooves in the optical axis direction. Guide pin 3
5 is inserted through the front group cam groove 22a and the lens guide groove 24a, and the guide pin 36 is formed in the rear group cam groove 22b and the lens guide groove 2a.
It is inserted through 4b.

The front group cam groove 22a and the lens guide groove 24a, and the rear group cam groove 22b and the lens guide groove 44 respectively have shapes
The movement of the cam ring 22 and the lens guide ring 24 in the optical axis direction as the inner helicoid ring 20 rotates, and the cam ring 22 and the lens guide ring 24.
Is set so that the moving lenses 15 and 16 can be given a predetermined movement trajectory in the optical axis direction.

In FIG. 6, a section 1 of the front group cam groove 22a and the rear group cam groove 22b is a zooming (zoom shooting) section which is a normal shooting area, and l2 is a macro transition section following the tele end of the zooming section 1, The same l3 is a storage section following the wide end of the zooming section 1. The macro transition section l2 is inclined in the opposite direction to the zooming section 1 with respect to a straight line parallel to the optical axis. In other words, if the lead angle of the zooming section 1 is positive, the lead angle of the macro transition section 12 is negative.

Next, other features of the present invention will be described. A pair of lens barriers 40 is provided at the tip of the lens cover cylinder 38. The lens barrier 40 is opened and closed in the storage section l3, closed at the storage position, opened between the storage position and the wide end, and maintained in the open state between the wide end and the macro position.

A pair of barriers 40, 40 are provided on the surface of a flange portion 38a projecting on the inner circumference of the front portion of the lens cover cylinder 38, and the pin 4 in the optical axis direction is provided.
It is pivoted through 1, 41. This barrier 40,40
Barrier plate that is symmetrical and faces the optical axis
40a and a drive arm portion 40b extending in a direction opposite to the barrier plate portion 40a with respect to the pin 41. A pin 42 extending in the optical axis direction is planted at the end of the drive arm 40b.
Extends rearward through a space inside the flange portion 38a.

On the back side of the flange 38a, a disc-shaped relay ring 43 with a hollowed center is provided as an opening / closing mechanism for opening / closing the barrier 40.
And the drive ring 45 is rotatably mounted. A groove 42a with which the pin 42 is engaged is formed on the inner circumference of the relay ring 43, and a projection 43b extending rearward in parallel with the optical axis is formed on the outer circumference.
And a relay engagement piece 43c is provided so as to project. Between the protrusion 43b and the pin 45c planted in the drive ring 45, a closing spring 44 for tensioning the lens barrier 40 in a direction to always close it is stretched.

A drive arm 45a, which is one of interlocking members and extends rearward in the optical axis direction, is formed on a part of the outer periphery of the drive ring 45. The drive arm 45a extends rearward through a gap between the cam ring 22 and the lens guide ring 24, and a pin 46 is planted at the tip thereof. The pin 46 is fitted in a barrier opening / closing cam groove 24c formed in the lens guide ring 24. Further, a cutout 45b is formed in a part of the outer circumference of the drive ring 45, and the relay engagement piece 43c of the relay ring 43 is engaged with the cutout 45b.

Further, the drive ring 45 includes the drive arm 45a and the lens cover tube 38.
An open spring 47 that is stretched between and is constantly biased in the barrier opening direction. Therefore, the drive ring 45
The pin 46 is always in contact with the barrier opening / closing cam groove 24c by the rotational biasing force of the opening spring 47. And relay ring 43
The relay engagement piece 43 is caused by the rotational biasing force of the normally-closing spring 44.
c contacts the inner wall of the cutout 45b of the drive ring 45,
It rotates following 45.

A barrier cover 48 that covers the lens barriers 40, 40 is fitted to the tip of the lens cover cylinder 38. The barrier cover 48 has a photographing opening 48a.

The present zoom lens with the above configuration has an inner helicoid ring.
When the outer helicoid ring 18 meshing with the 20 is rotated in the forward and reverse directions, the outer helicoid ring 18 is fixed to the fixed barrel 12, so that the inner helicoid ring 20 rotates while following the lead of the helicoid crest 20a in the optical axis direction. Move to. That is, the cam ring 22 fixed to the inner helicoid ring 20 rotates forward and backward integrally with the inner helicoid ring 20, and at the same time, the helicoid mountain 20
Move along the optical axis according to the lead of a.

Further, as the cam ring 22 moves in the optical axis direction, the lens guide ring 24 attached to the cam ring 22 so as to be relatively rotatable and integrally move in the optical axis direction, does not rotate but moves in the optical axis direction. Moving. With the relative rotation of the cam ring 22 and the lens guide ring 24, the cam groove 41, the lens guide groove 43, and the cam groove
Due to the relationship between 44 and the lens guide groove 44, the moving lenses 15, 16
Moves in the optical axis direction.

By moving the cam ring 22 and the lens guide ring 24, the movable lenses 15 and 16 can be moved from the stored state in FIG. 2 to the wide end in FIG. 3 to the macro end state. Moreover, since the cam ring 22 and the lens guide ring 24 do not project from the main body shell 11a and the lens cover cylinder 38 in the housed state, it can be seen that the housed length is extremely short.

The effect that the storage length is extremely short is that the cam ring 22 and the lens guide ring 24 advance and retreat together in the optical axis direction as the cam ring 22 rotates, and the moving lenses 15 and 16 cause the cam ring to move.
22 and a lens guide ring 24, and by relative rotation of the cam ring 22 and the lens guide ring 24, moving in the optical axis direction relative to the cam ring 22 and the lens guide ring 24,
Also, since the cam ring 22 moves back and forth in the optical axis direction, the cam groove 22
Even if the lead angles of a and 22b are set small, the moving lenses 15 and 16
This is because it is possible to secure a sufficient amount of movement in the optical axis direction, so that the total length of the cam ring 22 can be set short.

As described above, the cam ring 22 in the present embodiment rotates and simultaneously moves back and forth in the optical axis direction by the lead of the helicoid crest 20a. Therefore, in this embodiment, the length of the cam grooves 22a and 22b in the optical axis direction is shorter than the longest movement length of the movable lenses 15 and 16 in the optical axis direction by the movement length of the cam ring 22 in the optical axis direction. That is, the total length of the cam ring 22 may be shorter than the longest lens moving length by the moving length of the cam ring 22 in the optical axis direction.

Further, in the present embodiment, by reducing the lead angle of the cam grooves 22a, 22b, even if the movement distance by the action of the cam grooves 22a, 22b is shortened, the movement distance by the lead of the helicoid crest 20a does not change, that is, In this embodiment, if the lead angles of the cam grooves 22a and 22b are formed to be zero (on the plane orthogonal to the optical axis), the moving distance of the moving lenses 15 and 16 with respect to the cam ring 22 will be zero. Since 22 moves according to the lead of the helicoid mountain 20a, the moving lenses 15, 16
Moves for the lead of the helicoid mountain 20a.

That is, in the present embodiment, even if the rear group cam groove 22b is provided in the plane orthogonal to the optical axis, as the cam ring 22 rotates,
The moving lens 16 can be retracted to the storage position. This means that the cam grooves 22a and 22b formed in the cam ring 22 can be laid as a whole (the lead angle can be reduced). Therefore, the lengths of the cam grooves 22a and 22b and the lens guide grooves 24a and 24b in the optical axis direction can be shortened to shorten the cam ring 22 and the lens guide ring 24, and the movement accuracy of the movable lenses 15 and 16 can be improved.

The relationship between this lead and the cam grooves 22a and 22b is that the rear group cam groove 22
This is especially clear with reference to the storage section 13 of b. The storage section 13 is oriented on the cam ring 22 in a direction orthogonal to the optical axis. If the cam ring 22 only rotates and does not move in the optical axis direction as in the conventional case, the moving lenses 15 and 16 cannot be retracted. However, in this embodiment,
Since the cam ring 22 moves in the optical axis direction, the moving lenses 15, 16
Can be retracted.

Further, the required amount of movement of the movable lenses 15 and 16 at the time of shifting from the tele end to the macro photographing range is small. Therefore, in the present embodiment, the moving lenses 15, 16 with respect to the rotation amount of the cam ring 22.
In order to reduce the movement amount of, the excess movement amount is subtracted by the cam grooves 22a and 22b. That is, the cam groove
The lead angle of the macro transition section l2 of 22a and 22b is made negative, and the lead by the cam grooves 22a and 22b is made negative. As a result, the cam ring in the macro transition section l2
The moving distance of the moving lenses 15 and 16 with respect to the moving distance in the optical axis direction of 22 becomes shorter than that in the zoom section 1, and the cam ring
The moving distance in the optical axis direction of the movable lenses 15 and 16 with respect to the rotation angle of 22 is shortened. Therefore, since the moving distance of the moving lenses 15 and 16 with respect to the rotation angle of the cam ring 22 becomes short,
It is possible to secure a sufficient rotation angle of the cam ring 22 and obtain high movement accuracy. Moreover, since the lead of the macro transition section 12 is negative, the total length of the cam ring 22 is also short.

Next, the operation of the barrier, which is one of the features of the present invention, will be described. In the storage position shown in FIG. 2, the pin 46 rides on the inclined portion (barrier opening / closing drive portion) 24d of the barrier opening / closing groove 24c, and the drive ring 45 is closed in the closing direction against the rotational biasing force of the opening spring 47. Has been rotated to. Therefore, the relay ring
43 rotates following the rotation of the drive ring 45 in the closing direction, and rotates the pair of barriers 40, 40 until the barrier plates 40a, 40a close the optical path (FIGS. 2 and 5). reference).

When the motor 27 rotates from this state, as described above, the cam ring 22 rotates and moves in the optical axis direction, and the front group moving frame 34 advances with respect to the lens guide ring 24. Along with the front group moving frame 34, the lens cover 38, the driven ring 43 and the drive ring 45.
Moves forward, the pin 46 moves from the inclined portion 24d of the barrier opening / closing cam groove 24c to the optical axis direction portion. Therefore, the drive ring 45 is rotated in the opening direction by the rotational biasing force of the opening spring 47, the relay ring 43 is driven to rotate in the opening direction, and the pair of barriers 40 are respectively rotated in the opening direction (see FIG. 3). And FIG. 6). After that, even if the cam ring 22 rotates from the zoom range to the macro position, the pin 46 slides in contact with the optical axis direction portion of the barrier opening / closing cam groove 24c and is held at the rotating position. The state is maintained.

In this embodiment, the relay ring 43 is interposed between the barrier 40 and the drive ring 45, and the relay ring 43 and the drive ring 45
A closed spring 44 that urges the driven ring 43 to rotate in the closing direction is stretched between the two, and the relay projection 43c that interlocks the relay ring 43 and the drive ring 45 and the cutout 45b. I have some play in between. Therefore, when the drive ring 45 rotates in the closing direction, the relay ring 43 rotates in the closing direction while the relay protrusion 43c is in contact with one of the inner walls of the cutout 45b by the rotational biasing force of the closing spring 44. Then, each of the pair of barriers 40 is rotated in the closing direction. Then, when the facing edges of the barrier plate portions 40a of the pair of barriers 40 come into contact with each other and the rotation of the barriers 40 stops,
The rotation of the relay ring 43 also stops, but the drive ring 45 is notched 45
Since there is play between b and the relay protrusion 43c, the open spring 47 is further extended and rotated in the closing direction. Therefore, due to the excessive rotation of the drive ring 45, the manufacturing error and the assembly error of each member can be absorbed and the pair of barriers 40 can be completely closed.

It should be noted that, without providing the relay ring 43, a spring member for urging the pair of barriers 40 to rotate in the opening direction is provided.
Even if there is a play between the pin and the notch that interlock the drive ring 45 with the drive ring 45, the same effect as described above can be obtained.

In the above embodiments, the lens guide ring guide groove 12a and the lens guide grooves 24a and 24b are all formed as straight grooves. The use of these linear grooves has the advantage of facilitating the machining of these grooves and the setting of the shapes of the front group cam groove 22a and the rear group cam groove 22b. It does not prevent the lens guide grooves 24a and 24b from having a shape other than the straight groove. In short, the cam ring
The rotation of 22 causes the lens guide ring 24 to move together in the optical axis direction (which may include rotation), and the relative rotation of the cam ring 22 and the lens guide ring 24 causes the moving lenses 15, 16 to move.
The shapes of the lens guide ring guide groove 12a, the front group cam groove 22a, the rear group cam groove 22b, and the lens guide grooves 24a, 24b may be determined so that the lens group moves along the optical axis along a predetermined locus. .

Furthermore, the shapes of the barrier opening / closing cam groove 24c and the inclined portion 24d are the relative optical axis direction of the lens cover cylinder 38 and the lens guide ring 24,
It may be set according to the change in the rotational position.

In this embodiment, the inner helicoid ring 20 and the cam ring 22 are composed of separate members, and they are fixed with the fixing screw 21. However, these can be integrally molded with a resin material.

The lens barrel having the cam structure of the present invention can be used for a lens shutter type camera in which a fixed barrel is fixed to a camera body, and an interchangeable lens type camera that is detachable from the camera body.

Further, in the present embodiment, the moving lenses are the front and rear two groups.
The present invention is of course applicable to a lens barrel having moving lenses of groups or more. In this case, the cam groove for each moving lens may be formed in the cam ring. Such a lens barrel can be used, for example, as an interchangeable lens for a higher quality single-lens reflex camera.

As described above, in the zoom lens with barrier device of the present invention, the cam ring and the lens guide ring that rotate relative to each other move forward and backward along the optical axis while holding the moving lens, and the relative rotation of both Since the moving lens moves in the optical axis direction, the moving distance of the moving lens can be increased even if the length of the cam ring is short, and the storage length of the lens barrel can be shortened. Since the barrier is opened / closed by the movement of the lens guide ring in the optical axis direction, the structure of the barrier opening / closing device is simple, and the lens and camera can be made small and thin.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a zoom lens with a barrier device according to the present invention, and FIGS. 2 and 3 are end views showing the same embodiment in a longitudinal section except for a lens guide ring. FIG. 2 is a retracted state, FIG. 3 is an end view showing the wide end state, FIGS. 4 and 5 are front views showing the main part of the barrier portion, and FIG. 4 is a retracted state. State (closed state)
5 is a front view showing a wide end state (open state), and FIG. 6 is a development view of a cam ring, a lens guide ring, and an inner helicoid ring. 11 …… Camera body, 12 …… Fixed cylinder, 12a …… Lens guide ring guide groove, 15,16 …… Moveable lens, 18 …… Outside helicoid ring (inner circumference helicoid), 20 …… Inside helicoid ring (outer circumference helicoid) ), 22 …… Cam ring, 22a …… Front group cam groove, 22b …… Rear group cam groove, 24 …… Lens guide ring, 24a, 24
b …… Lens guide groove, 24c …… Barrier opening / closing cam groove, 24d
...... Inclined part (barrier opening and closing drive part), 26 …… Straight guide plate,
30 …… front group lens frame, 32 …… shutter book, 34 …… front group moving frame, 35, 36 …… guide pin, 38 …… lens cover tube, 40 …… lens barrier, 43 …… relay ring, 43a ......
Engagement groove, 43c ... Relay engaging piece, 44 ... Closing spring, 45 ... Drive ring, 45a ... Drive arm, 45b ... Notch, 46 ... Pin,
47-Open spring

Claims (2)

[Scope of utility model registration request] 1. A fixed barrel fixed to a camera body, a lens guide barrel that moves back and forth in the optical axis direction with respect to the fixed barrel, and at least a lens guide barrel movably guided in the optical axis direction. A zoom for moving the lens group of the front lens group and the lens cover tube which is guided by the lens group of the front lens group so as to be movable in the optical axis direction together with the lens of the front lens group to the storage position and the shooting position where zooming is possible. A lens, which is rotatably supported by the lens cover cylinder in a plane orthogonal to the optical axis and which opens and closes a photographing aperture of a zoom lens; and a plane which is orthogonal to the optical axis about the optical axis. Opening and closing a barrier having a ring member that rotates inside to open and close the barrier and an interlocking member that rotates the ring member when the lens cover cylinder moves between a shooting position and a storage position. Configuration; barrier device with a zoom lens comprising the. 2. The interlocking member according to claim 1, wherein the interlocking member has a drive arm extending outside the photographing optical path of the zoom lens in parallel with the optical axis and rotating about the optical axis, and the drive arm includes the lens cover. When the barrel moves between the storage position and the shooting position, the lens cover barrel is linked to the lens guide barrel, and when the lens cover barrel moves from the storage position to the shooting position, the pair of barriers is rotated in the opening direction. A zoom lens with a barrier device that rotates in a direction that closes a pair of barriers when the lens cover tube moves from the shooting position to the storage position.