JP2743649B2 - Zoom lens barrel - 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 barrel for moving two or more lens units in a video camera, an SV camera, a single-lens reflex camera or the like.

[0002]

2. Description of the Related Art Conventionally, a zoom lens barrel utilizing a lead screw and a face cam to move two or more lens groups in conjunction with each other has already been filed by the present applicant. However, no consideration has been given to the focus adjustment by the lens groups and the adjustment of the distance between the front and rear group lenses.

[0003]

However, in the above-mentioned conventional example, after assembling the lens groups into the lens barrel, the distance adjustment and the focus adjustment between the front and rear lens groups are simply taken into consideration while checking the image forming state. I didn't. For zoom lenses that require correction of lens group and lens barrel manufacturing errors, adjust the focus by inserting washers into the mount for attaching the lens barrel to the camera.
The lens group must be reassembled, and there is a problem that the error correction work is troublesome.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a zoom lens barrel in which two or more lens groups can be mounted on the lens barrel and then the distance between the front and rear lens groups and the focus can be easily adjusted.

[0005]

According to the present invention, there is provided a lead screw provided in parallel with an optical axis and supported movably in the optical axis direction, and a lens group which holds a lens group and is supported by the lead screw. At least two or more of the first and second
An engagement member for engaging the first lens barrel with a lead screw portion of the lead screw; and a second lens barrel screwed to the second lens barrel in parallel with an optical axis. By providing a cam follower pin for changing the distance between the cam follower provided on the lead screw and a spring for urging the second lens barrel so that the tip of the cam follower pin contacts the cam follower, the lead Focus adjustment can be performed by moving the first and second lens barrels holding the lens group through the screw integrally in parallel with the optical axis, and rotating the cam follower pin provided on the second lens barrel. hand,
The distance between the second lens barrel and the cam surface of the cam follower can be adjusted.

[0006]

1 to 3 are drawings showing the features of the present invention best. FIG. 1 is a longitudinal sectional view, FIG.
Is a plan view.

1 to 3, reference numeral 1 denotes a mount to be attached to a camera body (not shown), reference numeral 2 denotes a front frame of a lens barrel, and reference numeral 3 denotes a mount disposed in parallel with the optical axis and one end of which is provided in a concave portion 1a of the mount 1. A guide rod 4 whose other end is fitted and held in the concave portion 2a of the front frame 2 is a lead screw disposed in parallel with the optical axis. The other end is fitted to the recess 2b of the front frame 2 with the other end fitted into the recess 1b, and the tip of a screw 6 screwed into the front frame 2 to compress the spring 5 interposed between the one end face and the mount 1. Is held down.

Reference numeral 7 denotes a face cam fixed to a chamfered step 4b formed at one end of the lead screw 4, and this face cam has a cam surface 7a on its surface. Reference numeral 8 denotes a lens barrel that holds the front lens group 9. The lens barrel 8 has supporting arms 8a and 8b protruding on both sides, and an engaging recess 8a that engages with the guide rod 3 on the supporting arm 8a. -1, a sleeve 8 through which the lead screw 4 passes through the support arm 8b
b-1. Reference numeral 10 denotes a lens barrel that holds the rear lens group 20. The lens barrel 10 has support arms 10a, 1a on both sides.
The support arm 10a has an engagement recess 10a-1 that engages with the guide rod 3, and the support arm 10b has a sleeve 10b-1 through which the lead screw 4 passes.

Reference numeral 11 denotes a washer fitted to the recess 4 c of the lead screw 4, 12 denotes a washer fitted to the lead screw 4,
A spring interposed between the lens barrel 10 and the washer 11, 1
Reference numeral 3 denotes a follower pin which is screwed into a screw hole 10b-2 provided in the support arm 10b of the lens barrel 10 in parallel with the optical axis, and the penetrated tip spherical surface 13a is brought into contact with the cam surface of the face cam 7.
Reference numeral 4 denotes a leaf spring implanted in the lens barrel 8, and this leaf spring 14
Presses the steel ball 15 against the lead screw portion 4d of the lead screw 4.

Reference numeral 16 denotes an image pickup substrate for holding a solid-state image pickup device 17, and 18 denotes an image pickup substrate 1
7 is a stop screw.

In the above configuration, when the face cam 7 is rotated by an operating member or an actuator (not shown), the lead screw 4 integrated with the face cam 7 is rotated, and the lead screw 4d, the steel ball 15, and the leaf spring 14 are rotated. The lens barrel 8 holding the front lens group 9 moves in the optical axis direction using the guide rod 3 and the lead screw 4 as guides. At this time, the lens barrel 10 holding the rear group lens group 20 only fits the outer diameter of the lead screw 4 and is
Regardless of d, zooming is performed by moving in the optical axis direction along the shape of the cam surface 7a of the face cam 7.

Next, the operation of adjusting the zoom lens will be described. First, Tele is performed by the zooming operation.
Perform zoom operation to the end side, and hold
The follower pin 13 implanted in the lens is rotated to adjust the distance from the lens barrel 8. At this time, an image state may be confirmed by measuring a video signal from the solid-state imaging device 17 with a measuring device (not shown).

Thereafter, a zoom operation is performed to the Wide end side, and the screw 6 is rotated in the Wide end state, and the lens barrel 8 and the lens barrel 10 are moved in the optical axis direction without changing the above-mentioned distance to perform focus adjustment. Do. Thus, the operation of adjusting the distance between the lens barrels 8 and 10 on the Tele end side and performing the focus adjustment on the Wide end side is repeated to adjust the zoom lens.

Here, the front frame 2 shown in FIG. 1 and FIG.
In order to rotate the follower pin 13 from the front of the lens, a hole 2c for inserting a driver is formed, and the distance between the lens barrels 8 and 10 can be adjusted with the lens groups 9 and 20 incorporated.

The screw 6 to be rotated for focus adjustment can be adjusted in a state where the lens is mounted from the front of the lens.
It can be adjusted while checking the image formation state.

In the above embodiment, the face cam 7 as a separate member is fixed to the lead screw 4, but it is also possible to integrally form both of them by molding or die casting.

The distance between the front and rear lens barrels 8 and 10 and the focus can be adjusted by rotating the screw 6 and the follower pin 13 from the front of the lens. However, the relationship between the lead screw 4 and the face cam 7 is reversed. If the urging spring 5 of the lead screw 4 is brought to the front frame 2 and the focus adjusting screw 6 is brought to the mount side, it can be adjusted from the rear surface of the lens.

Instead of the follower pin 13 and the focus adjustment screw 6, eccentric rods may be implanted in the lens barrel 10 and the front frame 2, respectively, so that the lens can be adjusted from the outer peripheral direction of the lens.
Even in a zoom lens having two or more lens groups,
The same adjustment can be made by changing the phase of the follower pin 13 viewed from the front of the lens, that is, by turning each follower pin separately from the front of the lens.

Solid-state image pickup device 1 for confirming focus adjustment of a lens
Although the video signal of No. 7 is used, other optical detection means such as a transmission chart on the focal plane, light from behind, and projection of the chart on the front side of the lens to confirm focus adjustment Good.

[0020]

As described above, according to the present invention,
The lead screw is moved in the direction of the optical axis by a screw penetrating the support of the lens barrel to perform focus adjustment.The cam follower pin changes the distance between the lens barrels before and after in the optical axis direction, so that the zoom lens can be adjusted. Focus adjustment and zoom lens adjustment work can be performed efficiently with high accuracy. Therefore, it is possible to easily adjust a manufacturing error of a lens or a lens barrel after assembling the lens, and to provide a zoom lens barrel with sufficient performance of the lens.

[Brief description of the drawings]

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

FIG. 2 is a front view of FIG. 1;

FIG. 3 is a plan view of FIG. 1;

[Explanation of symbols]

 Reference Signs List 4 lead screw 5 spring 6 screw 7 face cam 8 lens barrel 9 lens group 10 lens barrel 20 lens group

Claims (2)

(57) [Claims] 1. A lead screw provided in parallel with an optical axis and supported so as to be movable in the optical axis direction, and at least two or more first screws holding a lens group and supported by the lead screw. A second lens barrel, an engagement member for engaging the first lens barrel with a lead screw portion of the lead screw, and a second lens barrel screwed into the second lens barrel in parallel with an optical axis. A cam follower pin for changing the distance between the cam follower provided on the lead screw and the cam follower; and a spring for biasing the second lens barrel so that the tip of the cam follower pin contacts the cam follower. Characteristic zoom lens barrel. 2. A lead screw, one end of which is regulated by a spring and the other end of which is regulated by a tip of a screw threaded through a fixing member, and by rotating this screw, the lead screw is passed through the lead screw. 2. The zoom lens barrel according to claim 1, wherein the first and second lens barrels supported on the lens barrel are integrally movable in parallel with the optical axis.