JP3186155B2 - Zoom lens adjustment mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens adjusting mechanism, and more particularly to a side-cam type zoom lens in which a rod-like cam member for moving a movable lens group during a zooming operation is arranged on the side of the movable lens group. It relates to an adjustment mechanism.

[0002]

2. Description of the Related Art Conventionally, this type of zoom lens adjusting mechanism has a pair of lens support rods 1, 2 arranged in parallel with an optical axis 3 as shown in FIG. 2, a first lens group 4, a second lens group 5, and a third lens group 6, which are moving lens groups, are respectively attached to a lens frame 7,
Attached so that it can move back and forth through 8,9. Then, the side cam 10 formed in a rod shape is attached to the lens frame 7,
The cam pins 11, 12, 13 formed on the lens frame bodies 7, 8, 9 are arranged in the cam grooves 14, 15, 16 formed on the side cams 10 by disposing the cam pins 11, 12, 13 on the side of the lens frames 7, 8, 9 on the sides of 8, 9 respectively. Insert.

[0003] At both ends of the side cam 10, rotatably provided cam shafts 18 and 20 are fixed, and a zoom motor 24 is connected to the cam shaft 20 via a gear mechanism 22 comprising a plurality of gears. Be linked. Therefore, when the side cam 10 is rotated by the rotational driving force from the zoom motor 24, the first lens group 4, the second lens group 5, and the third lens group 6 emit light along the cam grooves 14, 15, 16 Axis 3
It moves back and forth with a predetermined relationship in the direction. This allows
Zooming by the first lens group 4, the second lens group 5, and the third lens group 6 is performed.

Reference numeral 25 denotes a front lens, and reference numeral 2 denotes a front lens.
Reference numeral 6 denotes an iris plate, and reference numeral 27 denotes an iris motor for driving the iris plate 26.

[0005]

However, the conventional zoom lens adjusting mechanism requires the cam grooves 14, 15, and 16 of the side cam shaft 10 to be formed relatively shifted in the rotation direction due to an error in machining accuracy. Since the groove cannot be corrected, the position of the cam groove is difficult to adjust.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide a zoom lens adjustment mechanism that can easily adjust the position of a cam groove.

[0007]

In order to achieve the above object, according to the present invention, a bar-shaped cam member having a plurality of cam grooves is arranged on a side of a plurality of moving lens groups, and each of the plurality of moving lens groups is provided. In a zoom lens, each cam follower provided in each moving lens group is fitted into a cam groove, and each of the moving lens groups is moved back and forth in the optical axis direction with a predetermined relationship by rotating the cam member. The rod-shaped cam member includes a plurality of cylindrical divided cam members divided for each of the cam grooves,
In one of the plurality of divided cam members,
The shaft is integrally formed coaxially, and the remaining divided cam member is fitted around the outer periphery of the shaft, and the circumferential position of the remaining divided cam member is adjusted based on the one divided cam member. It is characterized by being possible.

[0008]

According to the present invention, the rod-shaped cam member is divided for each cam groove, the divided divided cam members are formed into a cylindrical shape, and these divided cam members are fitted into the cam shaft. Then, the divided cam members are relatively rotated in the circumferential direction so as to adjust the positions of the respective cam grooves so that the focus position at the time of zooming of the movable lens group becomes the normal focus position. Thus, the position of the cam groove can be easily adjusted.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A zoom lens adjusting mechanism according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a zoom lens adjusting mechanism according to the present invention, and the same or similar members as those in the conventional example shown in FIG.

According to FIG. 1, a pair of lens support rods 1, 2
Are arranged in parallel with the optical axis 3. The first lens group 4, the second lens group 5, and the third lens group
A lens group 6 is attached via lens frames 7, 8, 9 so as to be movable back and forth. On the sides of the lens frames 7, 8, and 9, a rod-like side cam 30 described later is provided.
Are arranged in parallel with the optical axis 3. The side cam 30 has three cam grooves 32, 34, 36 formed therein, and these cam grooves 32, 34, 36 are respectively provided with the lens frame bodies 7, 8, 9.
The cam pins 11, 12 and 13 formed in are fitted.

The side cam 30 is, as shown in FIG.
It has a cylindrical cam barrel 38, 40, 42 divided for each of the cam grooves 32, 34, 36, and a rotatable cam shaft 44 parallel to the optical axis 3 shown in FIG. I have. At the left end of the cam cylinder 42, a long thin cylinder (shaft) 46 is formed coaxially and integrally with the cam cylinder 42. Cam cylinder 42
And the thin cylinder 46 are provided with camshafts 44 in the hollow portions 42a and 46a.
And is fixed to the camshaft 44 by a pair of retaining rings 45, 45 attached to both sides thereof. In addition, the cam cylinders 38 and 40 have hollow portions 3.
8a and 40a, the narrow tube 46 is fitted into the cam tube 42.
And mounted on the same axis. Thereby, the cam cylinder 38,
The position of 40 in the circumferential direction is adjusted based on the cam cylinder 42 formed integrally with the thin cylinder 46. With such a configuration, the side cam 30 has the following effects. In other words, if all the cam cylinders 38, 40, 42 are provided rotatably with respect to the main cam cylinder, the thin cylinder 46 and the cam shaft 44, all the cam cylinders 38, 40, 42 are rotated to rotate around the circumference. Since it is necessary to adjust the position in the direction and fix it, there is a disadvantage that the adjusting operation and the assembling operation are troublesome. On the other hand, in the side cam 30, since one cam cylinder 42 is formed integrally with the narrow cylinder 46 of the main cam cylinder,
Is on the fixed side, so that only the two cam cylinders 38, 40 are rotated with respect to the narrow cylinder 46, and all the cam cylinders 38, 40
The circumferential positions of 40 and 42 can be adjusted. Also, since only the cam cylinders 38 and 40 need to be fixed, the side cam 30 can be easily assembled. Therefore, according to the side cam 30, the cam cylinders 38, 40,
The work of adjusting and assembling 42 does not require much work. Also, when reassembling the cam cylinders 38, 40 and 42 after disassembly and repair, the cam cylinders 3
Since it is only necessary to adjust the circumferential positions of 8, 40, the adjusted state before disassembly can be easily reproduced.

On the other hand, the cam cylinders 38 and 40 are formed with small diameter stepped portions 39 and 41 at the left ends in the drawing. Screw holes 48, 50 penetrating through the hollow portions 38 a, 40 a are formed in the stepped portions 39, 41, and bolts 52, 54 are screwed into the screw holes 48, 50, thereby forming the bolts 52, 5.
The cam cylinders 38 and 40 can be fixed to the narrow cylinder 46 at the tip of the fourth cylinder 4. Further, the cam cylinders 38 and 40 are provided with springs 56.
Is pressed against the cam cylinder 42 by the urging force.

A gear 58 is fixed to the right end of the cam cylinder 42 in the drawing. FIG.
The zoom motor 24 is connected via the gear mechanism 22 shown in FIG. Therefore, when the side cam 30 is rotated by the rotation driving force from the zoom motor 24, the first lens group 4,
The second lens group 5 and the third lens group 6 include the cam groove 3
It moves back and forth along the directions 2, 3, and 36 in the direction of the optical axis 3 with a predetermined relationship. Thereby, zooming by the first lens group 4, the second lens group 5, and the third lens group 6 is performed.

Reference numeral 25 denotes a front lens, and reference numeral 2 denotes a front lens.
Reference numeral 6 denotes an iris plate, and reference numeral 27 denotes an iris motor for driving the iris plate 26. Next, focus position adjustment during zooming of the first lens group 4, the second lens group 5, and the third lens group 6 using the zoom lens adjusting mechanism configured as described above will be described.

First, the cam cylinder 42 shown in FIG.
4, and then the cam cylinders 38 and 40 are sequentially fitted into the thin cylinder 46 and pressed against the cam cylinder 42 by the spring 56. next,
The cam pins 11, 12, 13 shown in FIG. 1 are fitted into the cam grooves 32, 34, 36 of the cam cylinders 38, 40, 42. Next, the cam cylinder 42 is moved relative to the cam shaft 44 and the cam cylinder 38 so that the first lens group 4, the second lens group 5, and the third lens group 6 are in focus at the time of zooming. , 40 are respectively rotated in the circumferential direction with respect to the thin cylinder 46 to determine the positions of the cam grooves 32, 34, 36. When the positions of the cam grooves 32, 34, 36 are determined, the bolts 5 are inserted into the screw holes 48, 50 of the cam cylinders 38, 40.
2, 54 are screwed into the cam cylinders 38, 40
Fixed to. Thereby, the position adjustment of the cam grooves 32, 34, 36 can be easily performed.

When the position of the cam groove 34 with respect to the cam groove 32 is to be finely adjusted, a guide of an adjusting jig 64 shown in FIG. This can be performed by inserting the pins 66 and 68 and turning the adjustment jig 64. That is, when the adjustment jig 64 is turned, the cam cylinders 38 and 40 relatively slightly rotate in the circumferential direction, so that the position of the cam groove 34 with respect to the cam groove 32 can be finely adjusted.

Further, when finely adjusting the position of the cam groove 36 with respect to the cam groove 34, similarly, the guide pins 66 of the adjusting jig 64 are inserted into a pair of holes 70, 72 formed in the cam cylinders 40, 42. , 68 inserted and turned. Therefore, in the present embodiment, the side cam 30 is divided into the cam grooves 32, 34, and 36, so that the cam grooves 32,
Position adjustment of 34 and 36 can be easily performed.

[0018]

As described above, according to the zoom lens adjusting mechanism of the present invention, the shaft is coaxially mounted on one of the plurality of divided cam members constituting the rod-shaped cam member. The remaining divided cam members are fitted into the outer periphery of the shaft body so that the circumferential position of the remaining cam members can be adjusted based on one divided cam member. In the circumferential direction adjustment work of the cam member and the assembling work, there is no trouble, and when reassembling a plurality of divided cam members after disassembly and repair, the remaining one is based on one fixed cam member on the fixed side. It is only necessary to adjust the circumferential position of the divided cam member and fix only the remaining divided cam members, so that the adjusted state before disassembly can be easily reproduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an adjustment mechanism of a zoom lens according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a side cam applied to the adjustment mechanism of the zoom lens according to the present invention.

FIG. 3 is a perspective view showing an embodiment of a cam adjusting jig applied to the zoom lens adjusting mechanism according to the present invention.

FIG. 4 is a sectional view showing an embodiment of a conventional zoom lens adjusting mechanism.

[Explanation of symbols]

 1, 2 support rod 4 first lens group 5 second lens group 6 third lens group 24 zoom motor 30 side cam 32, 34, 36 cam groove 38, 40, 42 cam cylinder 44 cam axis

Continuation of the front page (56) References JP-A-60-112009 (JP, A) JP-A-60-112008 (JP, A) Jikai Sho 61-194852 (JP, U)

Claims (1)

(57) [Claims] 1. A bar-shaped cam member having a plurality of cam grooves formed thereon is disposed beside a plurality of moving lens groups, and each cam follower provided in each moving lens group is provided in each of the cam grooves. fitted, said respective moving lens group by rotating the cam member with a predetermined relationship in the zoom lens is moved back and forth in the optical axis direction, the rod-like cam member has a plurality of divided for each of the cam groove
Of the plurality of divided cam members.
One of the split cam members has a shaft that is coaxial and integrally formed.
And the remaining divided cam member on the outer peripheral portion of the shaft body.
Is inserted, and the circumferential position of the remaining divided cam members is
An adjustment mechanism for a zoom lens, wherein the adjustment mechanism can be adjusted based on one split cam member .