JPH0443332A - Position adjusting device for lens group - Google Patents

Abstract

PURPOSE:To eliminate deviation due to lens locking after tracking adjustment by performing the tracking adjustment by moving a guide bar provided with a lens support frame forward and backward, and locking the axial movement of the guide bar by a clamp member after the tracking adjustment. CONSTITUTION:A moving cylinder 20B is moved finely first by moving a cam cylinder 20C finely by the rotation of an adjusting ring 25 on a telephoto side to adjust the tracking of the whole lens barrel. Then the guide bar 204 is moved forward and backward by unclamping the clamp member 38 on a wide-angle side to adjust the tracking of a 4th lens group 220, and after the adjustment, the clamp member 38 is clamped to lock the guide bar 204. At this time, the clamp member 38 restrains only the axial movement of the guide bar 204 and makes it free in the circumferential direction. Therefore, no external force operates on the guide bar 204 except axially. Consequently, even when a lens is fixed after the tracking adjustment, its deviation is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lens group position adjusting device, and more particularly to a lens group position adjusting device suitable for a zoom lens of a compact camera.

[Conventional technology]

Recently, compact cameras with high-power zoom lenses have been proposed.

The lens barrel of such a camera is configured such that a movable barrel is movable back and forth within a fixed barrel. For example, the lens group and the fourth lens group are fixed to the movable barrel, and the second lens group and the third lens group are fixed to the movable barrel. The movable barrel moves back and forth independently, and by rotating the cam barrel, the movable barrel and the second and third lens groups are moved, respectively.
Zooming is now available. To adjust the tracking of a compact camera with a zoom lens like this, you adjust the tracking of the entire lens barrel by slightly moving the movable barrel relative to the cam barrel on the telephoto side, and then adjust the tracking of the fourth lens group on the wide side. .

This adjustment is alternately repeated multiple times.

[Problem to be solved by the invention]

However, in conventional tracking adjustment, the tracking adjustment of the fourth lens group is performed by slightly moving the fourth lens group with a screw, and after adjustment, a set screw is embedded in the moving tube from the radial direction to adjust the tracking of the fourth lens group. Fix the lens support frame to the movable tube. Alternatively, the lens support frame is slightly moved using an eccentric pin.

For this reason, in the conventional locking mechanism after tracking adjustment, an external force is applied to the movable cylinder and the guide bar, which causes the tracking adjustment to go out of order.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a lens group position adjustment device that does not cause misalignment even when the lens support frame is locked after tracking adjustment.

[Means to solve problems]

The present invention provides a fixed cylinder in which a straight groove is formed in the axial direction, a cam cylinder in which a cam groove is formed and is rotatably supported on the outside of the fixed cylinder, and a cam cylinder in which a cam groove is formed and is rotatably supported on the outside of the fixed cylinder, and a cam cylinder is supported in an axially movable manner within the fixed cylinder. A guide pin planted outward in the direction is fitted into the straight groove of the fixed cylinder and the cam groove of the cam cylinder, and the cam cylinder is rotated to move the movable cylinder in the axial direction, and the movable cylinder is moved in the axial direction. A guide bar is provided to be able to move minutely, a lens support frame is fixed to the guide bar, and the axial movement of the guide bar is restricted after tracking adjustment of the lens provided on the movable cylinder and attached to the lens support frame. a clamp member;
It is characterized by consisting of.

[Effect]

In the present invention, a lens support frame is fixed to a guide bar, and lens tracking adjustment is performed while moving the guide bar back and forth. After tracking adjustment, the guide bar is restricted from moving only in the axial direction by the clamp member. Therefore, no external force acts on the guide bar except in the axial direction. As a result, there is little deviation even if the lens is fixed after tracking adjustment.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a lens group position adjusting device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a photographic lens barrel 20 of a camera according to the present invention, in which a movable barrel 20B is housed in a fixed barrel 2OA so as to be movable in the axial direction, and a cam barrel 20 is disposed on the outer periphery of the fixed barrel 20A.
0C is rotatably supported. A drive ring 20D is fixed to the outside of the cam cylinder 20C, and the drive ring 20D is driven by a gear transmission mechanism (not shown) via a gear 20E.

In the photographing lens barrel 20, a lens group 200 is fixed to the front part of the movable barrel 20B via a lens support frame 202. Further, a guide bar 204 is provided in the axial direction of the movable cylinder 2OB. The mounting structure of the guide bar 204 will be described later. The lens support frame 208 of the second lens group 206 is attached to a movable frame 210, and this movable frame 210 is supported by a guide bar 204 so as to be movable in the axial direction. Further, a guide bar 212 is provided in the axial direction of the movable cylinder 2OB, and this guide bar 212 is positioned within the groove 214 of the movable frame 210 to prevent the movable frame 210 from steadying. Furthermore, the moving tube 2O
In B, the third lens group 216 is the lens support frame 2.
It is supported by a guide bar 204 via a guide bar 204 so as to be movable in the axial direction, and is prevented from steadying by a guide bar 212.

A fourth lens group 220 is fixed to the movable barrel 2OB via a lens support frame 222. That is, the lens support frame 222
is fixed to the guide bar 204, and when the guide bar 204 is attached to the movable cylinder 20B, the lens support frame 2
22 is attached to the movable tube 2 (IB).

The photographic lens is lens group 200.206.216.22
It consists of 4 groups of 0 and 13 lenses.

The cam m20c has three JR1 cam grooves 224.224.
224 (only one shown), one second cam groove 225.1
A third cam groove 229 is formed. As shown in FIG.
26 penetrates inside the straight groove 227 of the fixed cylinder 2OA,
Furthermore, it is located in the first cam groove 224. Therefore, when the cam cylinder 20C rotates in this state, the movable cylinder 2OB moves to the fixed cylinder 20C.
It is regulated by the straight groove 227 of A and the first cam groove 224 to move back and forth in the axial direction.

Thereby, the lens group 200 and the fourth lens group 220 move together with the movable barrel 20B.

Similarly, the guide pin 231 protruding from the movable frame 210 of the second lens group 206 fits into the straight groove of the fixed barrel 2OA and also fits into the second cam groove 225 of the cam barrel 20C.
Therefore, when the cam cylinder 20C rotates, it moves back and forth. Further, a guide pin 233 is provided protrudingly on the lens support frame 218 of the third lens group 216, and this guide pin 233 is similarly located in the straight groove of the fixed barrel 2OA and in the third cam groove 229 of the cam barrel 20C. It is located in Therefore, when the cam cylinder 20C rotates, the third lens group 216 also moves back and forth.

Next, a tracking adjustment mechanism for the entire lens mirror will be explained. An adjustment ring 25 is rotatably supported at the distal end of the fixed cylinder 2OA, and this adjustment ring 25 is screwed into the inside of the distal end of the cam cylinder 20C by a screw connection 26. As a result, when the adjustment ring 25 is rotated, the cam cylinder 20C is moved to the fixed cylinder 2.
It moves minutely in the axial direction with respect to the OA. As a result, tracking adjustment is performed by slightly moving the movable barrel 2OB.

Next, the tracking adjustment mechanism of the fourth lens group will be explained. The fourth lens support frame 222 is fixed to the guide bar 204, and the guide bar 204 is provided so as to be able to move minutely in the axial direction with respect to the movable barrel 2OB. Further, the fourth lens support frame 222 is stabilized by the guide bar 212. The left end of the guide bar 204 is the support piece 30 of the movable cylinder 2OB.
The right end is inserted into the hole 36 of the guide bar support member 34 of the movable cylinder 2OB, and the left end is inserted into the hole 32 of the guide bar support member 34 of the moving cylinder 2OB.
7 urges the guide bar 204 to the right.

The guide bar support member 34 is attached to the movable cylinder 2OB by screws 39.
The recess 3 of the guide bar support member 34 is attached to the rear end of the guide bar support member 34.
A clamp member 38 is provided at 4A.

The clamp member 38 is attached to the guide bar 20 as shown in FIG.
The clamping part 40 and the tightening part 4 are so that the right end of the part 4 can be clamped.
It consists of 2. A screw 44 is screwed into the tightening portion 42, thereby locking the right end of the guide bar 204 with the clamping portion 40.

The clamp member 38 is arranged within the recess 34A with a slight gap, and the clamp member 38 is slightly movable in the circumferential direction of the guide bar 204. Furthermore, the clamp member 38
is fixed to the guide bar support member 36 with a stop plate 46.

The stop plate 46 is fixed to the guide bar support member 34 with screws 48, 48.

The operation of the lens group position adjusting device according to the present invention, which is constructed as described above, is as follows.

First, the adjustment ring 25 is rotated on the telephoto side to slightly move the cam barrel 20C, thereby moving the movable barrel 2OB slightly to adjust the tracking of the entire lens barrel.

Next, loosen the clamp member 38 on the wide side, move the guide bar 204 back and forth to adjust the docking of the fourth lens group 220, and after adjustment, tighten the clamp member 38,
Lock the guide bar 204. At this time, the clamp member 38 restricts only the movement of the guide bar 204 in the axial direction, and is free in the circumferential direction. Both of these tracking adjustments are alternately repeated multiple times.

In the above embodiment, the guide bar 204 also serves as a guide bar for the second and third lens groups, but in addition to the guide bar for the second and third lens groups, it is also used as a dedicated guide bar for the fourth lens group 204. may be provided to perform tracking adjustment.

〔Effect of the invention〕

As explained above, according to the lens group position adjustment device according to the present invention, the lens support frame is provided on the guide bar, tracking adjustment is performed by moving the guide bar back and forth, and after the tracking adjustment, the guide bar is moved to the clamping member. Since the axial movement is locked, no other external force acts on the guide bar, and even if the lens is locked after tracking adjustment, it will not go awry.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a lens barrel to which a lens group position adjustment device according to the present invention is applied. Figure J2 is shown as ■- on Figure 1.
It is an n-line arrow view. 2OA...Fixed tube, 20B...Moving tube, 0C
...Cam cylinder, 4...Guide bar

Claims (1)

[Scope of Claims] A fixed cylinder in which a straight groove is formed in the axial direction, a cam cylinder in which a cam groove is formed and rotatably supported on the outside of the fixed cylinder, and a cam cylinder in which a cam groove is formed and is supported rotatably in the axial direction within the fixed cylinder. A movable cylinder, which is moved in the axial direction by rotating the cam cylinder, and a movable cylinder in which the guide pin, which is planted radially outward, is fitted into the straight groove of the fixed cylinder and the cam groove of the cam cylinder, and the cam cylinder is rotated. A guide bar that can be moved minutely in the axial direction, a lens support frame that is fixed to the guide bar, and a lens that is installed on a movable tube and attached to the lens support frame. After adjusting the tracking of the lens, the guide bar can be moved in the axial direction. A lens group position adjustment device comprising: a clamp member for restraining; and a lens group position adjustment device.