JPH0511162A - Zoom lens barrel - Google Patents

Abstract

PURPOSE:To miniaturize a zoom lens barrel. CONSTITUTION:A moving means 14 is provided between a fixed barrel 13 and a cam ring 22. An advancing guiding board 30 is provided in parallel with the moving means 14 inside the cam ring 22. The advancing guiding board 30 controls the rotation of the moving frame 25 of a rear group. The advancing guiding groove 34 of the moving frame 25 of the rear group controls the rotation of the moving frame 35 of a front group. Consequently, an advancing guiding constitution is not provided on the fixed barrel 13, the outside diameter of the fixed barrel 13 can be small, the moving means 14 and the advancing guiding board 30 are lined up in parallel with an optical axis, and a thickness in a state where a lens is housed can be small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens barrel for a camera or the like.

[0002]

2. Description of the Related Art As a conventional zoom lens barrel, for example, a structure disclosed in Japanese Patent Laid-Open No. 1-306808 is known.

As shown in FIG. 8, a cam ring 2 is arranged inside the fixed cylinder 1, and a cam ring 2 is arranged on the front end side of the fixed cylinder 1.
There is provided a moving means 3 for moving the cam ring 2 in the optical axis direction with the rotation of the. In addition, this moving means 3
This is due to the engagement of the outer helicoid 3a on the fixed cylinder 1 side and the inner helicoid 3b on the cam ring 2 side.

A guide ring 4 which moves integrally with the cam ring 2 in the optical axis direction is arranged inside the cam ring 2, and a straight guide plate 5 provided at the rear end of the guide ring 4 is provided on the inner surface of the fixed barrel 1. It engages with the guide groove 1a formed along the optical axis direction, and restricts the rotation of the guide ring 4. Further, the guide ring 4 is formed with a straight guide groove 4a along the optical axis direction.

Inside the guide ring 4, there are arranged a rear lens group moving frame 7 supporting the rear lens group 6 and a front lens group moving frame 9 supporting the front lens group 8. The guide pins 7a and 9a provided on the movable frames 7 and 9 are inserted into the cam grooves of the cam ring 2 through the straight guide grooves 4a.
It is inserted through 2a and 2b.

Then, when the cam ring 2 is rotated by a driving means (not shown), the cam ring 2 moves in the optical axis direction and the guide ring 4 integrally moves in a rotation-restricted state. The movable frames 7 and 9 are moved in the optical axis direction according to the shapes of the cam grooves 2a and 2b of the cam ring 2 in a state where the rotation is restricted by the guide ring 4.

[0007]

By the way, recent demands for miniaturization of cameras are extremely strong, and particularly for zoom lens barrels, miniaturization of outer diameter dimension and thickness dimension when the lens is housed is required. ..

However, in the conventional zoom lens barrel as described above, the structure of the guide ring 4, the linear guide plate 5, and the guide groove 1a of the fixed barrel 1 is adopted in order to restrict the rotation of the moving frames 7 and 9. Therefore, it was difficult to reduce the size.

That is, since the fixed cylinder 1 is provided with the guide groove 1a, the outer diameter of the fixed cylinder 1 is correspondingly increased. Further, since the moving means 3, the guide groove 1a, and the straight guide plate 5 are arranged in series in the optical axis direction, the thickness dimension when the lens is housed becomes large.

The present invention has been made in view of the above points, and an object thereof is to reduce the size of a zoom lens barrel.

[0011]

According to the present invention, there is provided a fixed barrel 13,
A cam ring 22 arranged inside the fixed barrel 13 and provided with cam grooves 23, 24 for at least two lens groups 28, 38 in the front and rear.
A moving means (14) for moving the cam ring (22) rotated with respect to the fixed cylinder (13) in the optical axis direction with the rotation between the fixed cylinder (13) and the cam ring (22), and the inside of the cam ring (22). Is arranged along the optical axis direction, and the linear guide plate 30 having the rear end fixed to the fixed barrel 13 and the cam ring supporting the rear lens group 28.
An engaging portion that is arranged inside 22 and has a guide pin 33 that is inserted into a cam groove 23 for the lens group of the rear group of the cam ring 22, and that the linear guide plate 30 is inserted through and engages in the optical axis direction. 29 is formed, and the rear group moving frame 25 in which the linear guide groove 34 is formed in the optical axis direction and the rear lens group moving frame 25 supporting the front lens group 38 are arranged inside the rear lens group moving frame 25. A front group moving frame 35 having a straight guide groove 34 of 25 and a guide pin 40 inserted into the cam groove 24 for the front lens group of the cam ring 22 is provided.

[0012]

In the present invention, the linear guide plate 30 fixed to the fixed cylinder 13
The rotation of the rear group moving frame 25 is restricted by the
The rotation of the front group moving frame 35 is restricted by the straight guide groove 34.

The cam ring 22 rotated with respect to the fixed barrel 13 moves in the optical axis direction by the moving means 14 while rotating. By the rotation of the cam ring 22, the guide pin is inserted into the cam groove 23.
The rear group moving frame 25, whose rotation is restricted by the linear guide plate 30 while the 33 is inserted, moves in the optical axis direction along the cam groove 23. Further, the guide pin 40 is inserted into the cam groove 24, the guide pin 40 is inserted into the straight guide groove 34 of the rear group moving frame 25, and the rotation of the front group moving frame 35 is restricted. Move to.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an embodiment of the present invention will be described below with reference to FIGS.

In the drawing, 11 is a camera body, and 12 is a film surface set on the camera body 11.

A fixed barrel 13 is fixed to the front surface of the camera body 11. The inner surface of the fixed barrel 13 has a cam ring 22 to be described later.
An outer helicoid portion 15 is integrally formed as a moving means 14 for moving the optical axis in the optical axis direction. Also,
A window hole 17 in which a pinion gear 16 that is normally and reversely rotated by a zoom motor (not shown) is inserted and arranged in a part of the intermediate portion.
Are formed.

Inside the fixed barrel 13, an inner helicoid ring 18 is arranged as a moving means 14. The outer surface of the inner helicoid ring 18 is shown in FIG.
Outer helicoid part
An inner helicoid portion 19 that is screwed with 15 is formed, and a gear portion 20 that faces the inside of the window hole 17 and meshes with the pinion gear 16 is formed. In addition, this gear part 20
Is inclined at the same angle as the inner helicoid portion 19 so as to always face the inside of the window hole 17 and mesh with the pinion gear 16. A flexible printed circuit board 21 having a pattern for zoom position detection is attached to the outer surface of the inner helicoid ring 18.

A cam ring 22 is fixed inside the inner helicoid ring 18. As shown in FIGS. 2 and 6, cam grooves 23 and 24 for front and rear lens groups, which will be described later, are formed on the cam ring 22 at two positions on the circumference. Then, the cam ring 22 rotates integrally with the inner helicoid 18 and moves in the optical axis direction according to the lead of the helicoid.

A rear group moving frame 25 is arranged inside the cam ring 22 so as to be movable in the optical axis direction and rotatable relative to the cam ring 22. The rear group moving frame 25 has a base portion 26 slidably in contact with the inner peripheral surface of the cam ring 22, and a tubular portion 27 is formed so as to project forward from the base portion 26, and a rear lens is provided inside the base portion 26. Group 28 is supported.

Further, the base portion 26 is provided with two hole-shaped engaging portions 29 which are flush with the inner peripheral surface of the tubular portion 27 and penetrate in the optical axis direction, and the engaging portions 29 are linearly guided. Each plate 30 is inserted therethrough. In this linear guide plate 30, the fixed plate portion 31 at the rear end is fixed to the rear end surface of the fixed barrel 13, and the elongated plate-shaped guide plate portion 32 is inserted into the engaging portion 29 so as to be inside the rear group moving frame 25. They are arranged in parallel along the optical axis direction.

Guide pins 33 which are inserted into the cam grooves 23 of the cam ring 22 are provided at two positions on the outer surface of the base portion 26.

Therefore, the rear group moving frame 25 is a linear guide plate.
The rotation is restricted by 30 and the cam groove 22 rotates with the cam groove.
Follow 23 to move along the optical axis.

Further, in a part of the base portion 26 and the tubular portion 27, two straight guide grooves are provided corresponding to the cam grooves 24 of the cam ring 22.
34 is formed along the optical axis direction.

A front group moving frame 35 is arranged inside the rear group moving frame 25 so as to be movable in the optical axis direction. This front group moving frame 35
Supports a front lens group 38 mounted inside the shutter unit 36 and the lens frame 37. This shutter unit 36
A ring 39 is provided on the inside, and the ring 39 and the lens frame 37 are coupled by helicoidal screwing.

Guide pins 40, which are inserted into the cam grooves 24 of the cam ring 22 through the straight guide grooves 34 of the rear group moving frame 25, are provided at two positions on the rear side of the outer surface of the front group moving frame 35. ..
In addition, an escape groove portion 41 is formed to prevent interference with the guide plate portion 32 of each straight-ahead guide plate 30.

Therefore, the front group moving frame 35 is the rear group moving frame.
The rotation is regulated by 25, and the cam groove is rotated as the cam ring 22 rotates.
Move along the optical axis according to 24.

A lens frame outer cover is provided on the outer periphery of the front end of the cam ring 22.
42 is fixed, and a lens frame inner cover 43 is fixed to the outer periphery of the front end of the front group moving frame 35. This cover
A packing receiver 45 to which a packing 44 is attached is rotatably arranged between 42 and 43, and the packing 44 is in contact with the outer peripheral surface of the lens barrel inner cover 43 to prevent light leakage.

Next, the operation of this embodiment will be described.

When the pinion gear 16 is rotationally driven, the cam ring 22 moves in the direction of the optical axis according to the lead of the helicoid while rotating.

By the rotation of the cam ring 22, the guide pin 33 is inserted into the cam groove 23 and the rear group moving frame 25, the rotation of which is restricted by the rectilinear guide plate 30, moves in the optical axis direction along the cam groove 23.

Further, by the rotation of the cam ring 22, the guide pin 40 is inserted into the cam groove 24, and the guide pin 40 is inserted into the rectilinear guide groove 34 of the rear group moving frame 25 so that the rotation is restricted. 35 moves in the optical axis direction according to the cam groove 24.

The cam ring 22, the rear group moving frame 25, and the front group moving frame 35 move between the lens housed state shown in FIGS. 1 and 2 and the telephoto end state shown in FIG.

In the zoom lens barrel constructed as described above, the rear group moving frame is provided by the linear guide plate 30 fixed to the fixed barrel 13.
The rotation of the front group moving frame 35 is restricted by the straight guide groove 34 of the rear group moving frame 25.

Therefore, it is not necessary to provide a guide groove inside the fixed barrel as in the conventional case, and the outer diameter of the fixed barrel 13 can be reduced accordingly.

Moreover, an outer helicoid is provided inside the fixed cylinder 13.
It becomes possible to integrally form 15, and it is not necessary to form separate parts as in the conventional case, and the number of parts can be reduced. In addition, a guide ring (reference numeral 4 in FIG. 8) that was conventionally required
Can be eliminated and the number of parts can be reduced.

Further, moving means 14 for moving the cam ring 22
Since the linear guide plates 30 are arranged in parallel with the optical axis, the thickness of the lens housed state can be reduced.

The reduction in the thickness of the lens housed state will be described with reference to FIG. 7A and 7B show the lens housed state and the telephoto end state of this embodiment, and FIG.
8C and 8D show the lens housed state and the telephoto end state in the conventional case shown in FIG.

Conventionally, since the outer helicoid 3a of the moving means 3 and the guide groove 1a are arranged in series in the optical axis direction, as shown in FIG. 7C, the thickness W in the lens housed state is the outer side. It is the sum of the length of the helicoid 3a and the length of the guide groove 1a.

On the other hand, in this embodiment, the moving means 14
Since the linear guide plate 30 and the straight-ahead guide plate 30 are arranged in parallel with the optical axis, (a) in FIG.
As described above, the thickness dimension Y in the lens housed state depends on the length of the outer helicoid portion 15 or the length of the cam ring 22.

Therefore, although the lens lengths in the telephoto end state are substantially the same, the thickness dimension in the lens accommodation state is W> Y, and this embodiment can reduce the thickness dimension in the lens accommodation state. ..

[0041]

According to the present invention, the rotation of the rear group moving frame is restricted by the straight guide plate fixed to the fixed barrel, and the rotation of the front group moving frame is restricted by the straight guide groove of the rear group moving frame. Therefore, it is not necessary to provide a guide groove inside the fixed barrel as in the conventional case, and the outer diameter of the fixed barrel can be reduced accordingly. Further, since the moving means for moving the cam ring and the linear guide plate are arranged in parallel with the optical axis, the thickness dimension of the lens housed state can be reduced. Therefore, the zoom lens barrel can be downsized.

[Brief description of drawings]

FIG. 1 is a sectional view of a zoom lens barrel according to an embodiment of the present invention in a lens housed state.

FIG. 2 is a sectional view of a lens housed state.

FIG. 3 is a sectional view of a tele end state.

FIG. 4 is a sectional view.

FIG. 5 is a development view of an inner helicoid ring.

FIG. 6 is a development view of a cam ring.

FIG. 7 is an explanatory diagram comparing a dimensional relationship between the present embodiment and a conventional one.

FIG. 8 is a sectional view of a conventional zoom lens barrel.

[Explanation of symbols]

 13 Fixed cylinder 14 Moving means 22 Cam rings 23, 24 Cam groove 25 Rear group moving frame 28 Rear lens group 29 Engaging portion 30 Straight guide plate 33 Guide pin 34 Straight guide groove 35 Front group moving frame 38 Front lens group 40 Guide pin

Claims (1)

Claim: What is claimed is: 1. A fixed barrel, a cam ring which is disposed inside the fixed barrel, and in which cam grooves for at least two lens groups of front and rear are formed, and the fixed barrel and the cam ring. And a moving means for moving a cam ring rotated with respect to the fixed barrel in the optical axis direction as the rotation occurs, and a moving means disposed inside the cam ring along the optical axis direction and arranged on the fixed barrel. A straight guide plate having fixed ends, a guide pin that is arranged inside the cam ring to support the rear lens group, and is inserted into a cam groove for a lens group of the rear group of the cam ring, A rear group moving frame in which an engaging portion is formed through which the guide plate is inserted and engaged in the optical axis direction, and a linear guide groove is formed in the optical axis direction; and a rear group moving supporting the front lens group. For the front lens group of the cam ring, which is arranged inside the frame, and which is provided in the rectilinear guide groove of the rear group moving frame. A zoom lens barrel, comprising: a front group moving frame having a guide pin that is inserted into a cam groove.