JP3326253B2 - 3-stage extension zoom lens barrel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a three-stage extension zoom lens barrel.

[0002]

2. Description of the Related Art In recent compact cameras equipped with a zoom lens, in order to shorten the storage length, the lens barrel is extended from the camera body in use in some form. However, in the past, two-step feeding was common, and it was difficult to simultaneously achieve a reduction in the storage length (thinning of the camera body) and a demand for a high zoom ratio of the zoom lens. Recently, a three-stage extended zoom lens barrel has also been commercialized. However, in the conventional product, the expansion and contraction mechanism and the drive mechanism have become large, and it has been difficult to reduce the size of the entire camera.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a zoom lens barrel which is a three-stage extended zoom lens barrel, which has a simple expansion and contraction mechanism and a driving mechanism, and which can be easily miniaturized.

[0004]

SUMMARY OF THE INVENTION A three-stage extended zoom lens barrel according to the present invention comprises:
A rotating cylinder driven to rotate; a first advancing and retreating cylinder that moves straight in the optical axis direction by the rotation of the rotatable cylinder; a second thread that is screwed to the first advancing and retreating cylinder and moves in the optical axis direction when rotated.
An advancing and retreating cylinder; at least two front and rear movable zoom lens groups which advance and retreat in the optical axis direction with the rotation of the second advancing and retreating cylinder; and a rotation transmitting mechanism for transmitting the rotation of the rotating cylinder to the second advancing and retreating cylinder. It is characterized by having.

[0005]

SUMMARY OF THE INVENTION A three-stage extended zoom lens barrel according to the present invention comprises:
A rotating cylinder driven to rotate; a first advancing and retreating cylinder that moves straight in the optical axis direction by the rotation of the rotatable cylinder; a second thread that is screwed to the first advancing and retreating cylinder and moves in the optical axis direction when rotated.
A reciprocating cylinder; and a movable lens group of the at least two front and rear groups are moved in the optical axis direction by rotation of the second reciprocating cylinder; the
With the rotation of the second advance / retreat cylinder,
A third advancing and retreating cylinder that independently advances and retreats in the optical axis direction; and a rotation transmission mechanism that directly transmits the rotation of the rotary cylinder to the second advancing and retreating cylinder without passing through the first advancing and retreating cylinder. Features. Since the three-stage extended zoom lens barrel directly transmits the rotation of the rotary barrel to the second advance / retreat barrel, it is not necessary to rotate the rotary barrel and the second advance / retreat barrel independently, and the drive mechanism is simplified. be able to.

More specifically, the rotation transmitting mechanism includes a pinion rotatably supported in a state in which a part of the tooth surface protrudes from the outer peripheral surface of the first advance / retreat cylinder; An inclined inner gear provided to be inclined with respect to the circumferential direction so as to always mesh with the pinion; an inner gear provided on the inner peripheral surface of the second advance / retreat cylinder; A take-out pinion supported by the second advance / retreat cylinder; and a gear mechanism that constantly transmits the rotation of the first advance / retreat cylinder side pinion to the take-out pinion regardless of the relative positions of the first advance / retreat cylinder. Thus, a smaller transmission mechanism can be obtained.

In addition, at least a movable variable magnification lens group is constituted.
So that both lenses are supported by the second retraction cylinder
can do.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In this embodiment, a zoom lens system is constituted by the front lens group L1 and the rear lens group L2, and focusing is performed by the front lens group L1.

The fixed lens barrel 11 integrated with the camera body has an inner cylinder 11a and an outer cylinder 11b. The rear ends of the inner cylinder 11a and the outer cylinder 11b are connected by a connection wall 11c, and the front end is open.
A rotary cylinder 12 is rotatably fitted on the outer periphery of 1a. A straight guide groove 11e in a direction parallel to the optical axis is provided on the inner surface of the inner cylinder 11a.

The rotary cylinder 12 is provided with a flat spur gear 12a in the circumferential direction on the outer circumference thereof, and a fine screw 12b on the outer circumference of the distal end thereof. On the inner surface thereof, a lead groove 12c inclined in the circumferential direction and an inclined inner gear 12d parallel to the lead groove 12c and inclined in the circumferential direction are formed. At the open end of the front end of the inner cylinder 11a and the outer cylinder 11b of the fixed lens barrel 11, a fitting part 13a with the inner surface of the outer cylinder 11b, a screw part 13b screwed to the fine screw 12b, and an outer surface of the inner cylinder 11a Abutting portion 13c that abuts
And the support ring 13 having the outer flange 13e is fixed. The support ring 13 is pressed toward the fixed lens barrel 11 (P direction) by a biasing means (not shown) and is held at a fixed position. 13d is a gear for rotating operation formed on the outer peripheral surface of the support ring 13. With this support ring 13, it is possible to eliminate insufficient strength at the openings of the inner cylinder 11a and the outer cylinder 11b.

The outer cylinder 11b of the fixed lens barrel 11 has a spur gear 1
Notch 11d for pinion 11f meshing with 2a is provided, and similar notch for exposing lead groove 12c and inclined inner gear 12d is provided in inner cylinder 11a.

A first advance / retreat cylinder 14 that moves straight in the optical axis direction is fitted on the inner periphery of the inner cylinder 11a of the fixed lens barrel 11. On the outer periphery of the first advancing / retreating cylinder 14, a rectilinear guiding projection 14a which fits into the rectilinear guiding groove 11e of the fixed lens barrel 11 is integrally provided.
A pin 14b that fits into the second lead groove 12c is provided. A female helicoid 14c and a straight guide groove 14d parallel to the optical axis are formed on the inner periphery of the first advance / retreat cylinder 14. According to the above relationship, when the rotary cylinder 12 is driven to rotate, it follows the straight guide groove 11e and the lead groove 12c.
The first advance / retreat tube 14 advances / retreats in the optical axis direction without rotating.

A second advance / retreat barrel (cam ring) 15 is fitted on the inner periphery of the first advance / retreat barrel 14, and a female helicoid 14 c of the first advance / retreat barrel 14 is fitted on the outer peripheral rear portion of the second advance / retreat barrel 15. Is formed with a male helicoid 15a. A rectilinear guide member 16 is located on the inner circumference of the second reciprocating cylinder 15, and a gear support / straight guide plate 17 is fixed to a rear end portion of the rectilinear guide member 16 with a fixing screw 19. An inner flange 1 is rotatably held between the rectilinear guide member 16 and the rectilinear guide plate 17 on the second reciprocating cylinder 15.
5b (see FIGS. 7 and 8) is formed, and a straight guide key 17a formed on the straight guide plate 17 is fitted into a straight guide groove 14d of the first advance / retreat cylinder 14. Therefore,
The rectilinear guide member 16 and the rectilinear guide plate 17 can freely rotate relative to the second reciprocating barrel 15 and move integrally in the optical axis direction.
That is, when the second advance / retreat cylinder 15 rotates, it moves in the optical axis direction while rotating according to the male helicoid 15a and the female helicoid 14c, while the straight guide member 16 and the straight guide plate 17 do not rotate. It moves in the optical axis direction together with the binary retraction cylinder 15.

The rectilinear guide member 16 is provided with a rectilinear key 16b in a direction parallel to the optical axis.
The straight key 18a of the front group straight guide member 18 is engaged with 6b. The front group straight guide member 18 has a fixing screw 2
1, the shutter block 20 is fixed, and the shutter block 20 further includes a front lens support cylinder (third advance / retract cylinder).
2 so that the shutter block 20
The rotation of the front lens support cylinder 22 is restricted, and only the movement in the optical axis direction is possible.

The shutter block 20 has a female helicoid 20a on its shaft, and the female helicoid 20a
The male helicoid 23a of the front group lens frame 23 to which the front group lens L1 is fixed is screwed. The shutter block 20
As is well known, the front group lens frame 23 is rotated in accordance with the helicoids 20a, 23a via the drive pin 20b and the linking projection 23b based on the subject distance signal from the distance measuring device, and is moved to the in-focus position. A male helicoid 22a for moving the front lens support cylinder 22 in the optical axis direction during zooming is formed at the rear end portion of the outer peripheral surface.
The shutter block 20 also has a shutter blade 20c that opens and closes according to a subject luminance signal. A drive signal is supplied to the shutter block 20 via the FPC board 20d.

On the other hand, the front group straight guide member 18 is formed with a rear group guide surface 18b for moving the rear group lens L2 straight in the optical axis direction. The rear group lens L2 is fixed to the rear group lens frame 24.
Then, the rectilinear key 24a engaged with the rear group guide surface 18b
Is provided. And on this straight key 24a,
A cam pin 24b is formed to protrude.

A female helicoid 15c for screwing the male helicoid 22a of the front group lens support cylinder 22 and a cam pin 24b of the rear group lens frame 24 are fitted into the inner peripheral surface of the second advance / retreat cylinder (cam ring) 15. A cam groove 15d to be formed is formed. The cam groove 15d is mixed with the helicoid at the same circumferential position so as to cut off a part of the female helicoid 15c. At the time of assembly, the cam pin 24 of the rear lens group frame 24 is inserted into the open groove 22b at the rear end of the front lens group support cylinder 22.
b, and in this state, the cam pin 24b is inserted into the cam groove 15d.
Next, the male helicoid 22a is engaged with the female helicoid 15c. In this engaged state, when the second advance / retreat cylinder 15 rotates, the screw engagement between the female helicoid 15c and the male helicoid 22a, and the straight key 16b of the straight guide member 16 and the straight key 18a of the front group straight guide member 18, , The front-group lens support cylinder 22 (front-group lens L1) moves straight in the optical axis direction, and the cam groove 1
5d and cam pin 24b, and rear group lens frame 2
4, the rear group lens frame 24 (rear group lens L2) moves along a predetermined trajectory in the optical axis direction due to the rectilinear guide relationship between the rectilinear key 24a of No. 4 and the rear group guide surface 18b of the front group linear guide member 18. Done.

As described above, when the rotary barrel 12 is rotationally driven, the first advance / retreat barrel 14 moves straight in the optical axis direction, and when the second advance / retreat barrel 15 rotates with respect to the first advance / retreat barrel 14, the first advance / retreat barrel 15 rotates. It can be seen that the binary retreat cylinder 15 moves in the optical axis direction while rotating, and the front lens group L1 and the rear lens group L2 move straight while changing the air gap, thereby performing zooming.

Next, a drive mechanism for rotating the second advance / retreat cylinder 15 will be described. This rotation drive mechanism basically transmits the rotation of the rotary cylinder 12 to the second advance / retreat cylinder 15. A pair of gear support plates 26 and 27 are fixed to the rear end of the first advancing / retreating cylinder 14 by fixing screws 29. The gear support plate 26 rotatably supports a pinion 30 that meshes with the inclined inner gear 12 d of the rotary cylinder 12. The pinion 30 is stored in a pinion storage space 14 e formed on the rear end surface of the first advance / retreat cylinder 14. In addition, a part of the tooth surface protrudes from the outer surface of the first advance / retreat cylinder 14. The inclined inner gear 12d of the rotary cylinder 12 is
2c, the meshing relationship between the pinion 30 and the inclined inner gear 12d is maintained even if the first advance / retreat cylinder 14 moves in the optical axis direction due to the rotation of the rotary cylinder 12. A gear train 31 receiving the rotation of the pinion 30 is supported between the gear support plates 26 and 27.
A rotation transmission shaft 32 extending forward is integrally fixed to the shaft portion a. The rotation transmission shaft 32 has a non-circular uniform cross section.

On the other hand, a linear guide plate 17 fixed to the rear end face of the linear guide member 16 has the rotation transmitting shaft 3.
The take-out pinion 33, which is freely movable in the axial direction relative to 2 and rotates integrally, is supported in a state where the axial movement with respect to the linear guide plate 17 is restricted. That is, the take-out pinion 33 is always in the linear guide plate 17 (and the second advance / retreat cylinder 1).
5) and move together in the optical axis direction. The takeout pinion 33 meshes with a circumferential inner gear 15 e formed on the inner surface of the second advance / retreat cylinder 15. Therefore, the rotating cylinder 12
Rotation of the inclined inner gear 12d, the pinion 30, and the gear train 3 regardless of the position of the first advance / retreat cylinder 14 in the optical axis direction.
1. The rotation is transmitted to the second advance / retreat cylinder 15 via the rotation transmission shaft 32, the takeout pinion 33, and the circumferential inner gear 15e.

In the zoom lens barrel having the above-described structure, when the rotary barrel 12 is driven to rotate, the first advance / retreat barrel 14 moves straight in the optical axis direction, and the second advance / retreat barrel 15 rotates. When the second advance / retreat cylinder 15 rotates, it moves in the optical axis direction, and the front group lens L1 and the rear group lens L2 move straight while changing the air gap, and zooming is performed.

[0022]

As described above, the three-stage extension zoom lens barrel according to the present invention is such that the first advance / retreat barrel, the second advance / retreat barrel, the third advance / retreat barrel, and the movable zoom lens group advance / retreat in the optical axis direction. So,
The driving is performed by rotating the rotary cylinder and the second advance / retreat cylinder. Then, since the rotation of the rotary barrel is directly applied to the second advance / retreat barrel via the rotation transmission mechanism, a simple zoom lens barrel having a drive mechanism and a telescopic mechanism can be obtained. According to the rotation transmission mechanism of the second aspect, the rotation of the rotary cylinder is directly transmitted to the second advance / retract cylinder regardless of the relative position of the first advance / retreat cylinder.
It is possible to easily obtain a rotation transmitting mechanism for transmitting the contact .

[Brief description of the drawings]

FIG. 1 is an overall exploded perspective view schematically showing an embodiment of a lens barrel according to the present invention.

FIG. 2 is an enlarged perspective view of a rear part of the lens barrel in FIG.

FIG. 3 is an enlarged perspective view of an intermediate portion of the lens barrel in FIG.

FIG. 4 is an enlarged perspective view of a front part of the lens barrel of FIG. 1;

FIG. 5 is a perspective view showing a support mechanism of a power transmission system of the lens barrel of the present invention.

FIG. 6 is a perspective view showing the relationship of only the gears of the power transmission system.

FIG. 7 is an upper half sectional view of the lens barrel of the present invention in a housed state.

FIG. 8 is an upper half view of the vertical section in the longest feeding state.

[Explanation of symbols]

L1 Front lens group L2 Rear lens group 11 Fixed lens barrel 12 Rotating cylinder 12a Flat gear 12c Lead groove 12d Inclined inner gear 13 Support ring 14 First advance / retreat cylinder 15 Second advance / retreat cylinder 15e Circumferential inner gear 16 Straight guide member 17 Straight guide plate 18 Front group straight guide member 20 Shutter block 22 Front group lens support cylinder (third advance / retract cylinder) 23 Front group lens frame 24 Rear group lens frame 26 27 Gear support plate 30 Pinion 31 Gear train 32 Rotation transmission shaft 33 Take-out pinion

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B ⁷ /02-7/105

Claims (3)

(57) [Claims] A rotating cylinder driven to rotate; and a first cylinder that moves straight in the optical axis direction by rotation of the rotating cylinder.
An advancing and retreating cylinder; a second advancing and retreating cylinder that is screwed to the first advancing and retreating cylinder and that moves in the optical axis direction when given a rotation; A movable variable power lens group; and a movable variable power lens group by rotating the second advance / retreat cylinder.
A third advancing and retreating cylinder that advances and retreats in the optical axis direction independently of the above ; and rotating the rotating cylinder without passing through the first advancing and retreating cylinder
And a rotation transmission mechanism for directly transmitting the rotation to the second advance / retreat cylinder. 2. The three-stage extended zoom lens mirror according to claim 1.
In the cylinder , the rotation transmission mechanism rotates with the tooth surface partially protruding from the outer peripheral surface of the first advance / retreat cylinder.
A pinion rotatably supported ; and an inclined inner gear provided on the inner peripheral surface of the rotary cylinder so as to be inclined with respect to the circumferential direction so as to always mesh with the pinion; and provided on an inner peripheral surface of the second advance / retreat cylinder. A take-out pinion supported by the second advance / retract cylinder so as to always mesh with the inner gear of the second advance / retract cylinder; regardless of the relative positions of the first advance / retreat cylinder and the second advance / retreat cylinder, the rotation of the pinion And a gear mechanism for constantly transmitting the gear to the take-out pinion. 3. The three-stage extended zoom lens mirror according to claim 1,
At least one of the movable variable magnification lens groups
A three-stage extended zoom lens barrel in which two lenses are supported by a second advance / retreat barrel.