JPH0743578A - Lens barrel - Google Patents

Abstract

PURPOSE:To eliminate an uncertain factor such as stick slip between bearings, to make movement smooth and to prevent the vignetting of a picture from occurring by providing a tilt regulation guide for an iris unit which is constituted to be pressed by a spring so as to change its position between a telephoto side and a wide angle side in a main body. CONSTITUTION:This lens barrel is provided with a 1st group lens unit 1 constituted of plural lenses, a 2nd group lens unit 2 moving between the telephoto side and the wide angle side, and a 3rd group lens unit 3 constituted to be able to move in an optical axis direction. Furthermore, it is constituted of the main body 4 holding the lens units 1, 2 and 3, a frame body 5, an image pickup means 6, and the iris unit 7 constituted so as to change its position between the telephoto side and the wide angle side interlocked with the action of the lens unit 2; and the tilt regulation guide 10 for the iris unit 7 is provided in the main body. When the iris unit 7 acts to tilt, the guide 10 regulates the further tilt, whereby the stick slip is not caused and the smooth sliding of the iris unit 7 is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel used in a video camera.

[0002]

2. Description of the Related Art In recent years, lens barrels have been used in a wide range and are required to have smaller size, lighter weight and reliable operation (reliability). A conventional lens barrel will be described below with reference to FIGS. 2 and 3.

Reference numeral 1 is a first lens group unit composed of a plurality of lens balls, 2 is a second lens group unit that is movable between a telephoto side (A) and a wide angle side (B), and holds a lens 17.
Reference numeral 3 is a third group lens unit for holding the lens 18 and focusing on the image pickup means 6, 4 is a main body, and 5 is a frame. 7 is a second group lens unit 2 and a third group lens unit 3
In the iris unit located between, 7a is a meter part, 7b
Is a blade. Reference numeral 8 is a stopper of the iris unit 7, 9 is a biasing spring of the iris unit 7, 11 is a guide pole for guiding the second group lens unit 2 and the iris unit 7, and 12 is a swinging control of the second group lens unit 2. It is a key groove provided in the main body 4. Reference numeral 2a denotes a convex portion provided on a part of the second group lens unit 2, which is adapted to be operated by an operation signal at an engaging portion with a driving means such as a conventionally known motor. 13 is a screw portion provided on the frame body 5,
It meshes with a screw portion 14 provided on the third group lens unit 3 to enable the third group lens unit 3 to move back and forth. Reference numeral 15 is a boss end of the second lens unit 2, and 16 is a boss end of the iris unit 7. Reference numeral 19 indicates an optical axis. Next, the operation will be described.

FIG. 2 is a view showing a state in which the lens is set to the telephoto side (the second group lens unit 2 is at the position (A)), and the iris unit 7 is urged by the spring 9 and is in contact with the stopper 8. When used in a wide-angle state, the motor (not shown) is rotated by an operation signal, and the convex portion 2 of the second group lens unit 2 is rotated.
Power is transmitted via a, and the second group lens unit 2 is moved from the position (A) to the position (B). At this time, the boss end 15 of the second group lens unit 2 contacts the boss end surface 16 of the iris unit 7 to move the iris unit 7 from the position (C) to the position (D).

[0005]

When the lens barrel having the above-mentioned structure is used, the lens barrel operates normally when used horizontally, but when the lens barrel is directed downward, for example,
As shown in FIG. 3, the meter unit 7 a of the iris unit 7
Depending on the weight of, it rotates in the direction of the arrow by the amount of backlash. Therefore, the boss of the iris unit 7 and the guide pole 1
Sliding with 1 deteriorates and stick-slip occurs, and normal operation stops, and in the worst case, the iris unit 7 locks during operation. Therefore, vignetting occurred on the screen.

An object of the present invention is to improve the problems in the operation of the above-mentioned conventional iris unit 7.

[0007]

In order to solve the above-mentioned problems, a lens barrel according to the present invention comprises a first group lens unit composed of a plurality of lenses and a telephoto side and a wide-angle side.
3 configured to be movable in the optical axis direction together with the group lens unit
A group lens unit and a main body that supports the lens unit,
A structure in which a frame body, an image pickup means, and an iris unit configured to change its position on the telephoto side and the wide-angle side in association with the operation of the second group lens unit are provided in the main body with a tilt control guide for the iris unit. have.

[0008]

With the above structure, when the iris unit is about to fall, the regulation guide provided on the main body prevents the iris unit from falling further, and a smooth iris is produced without causing a stick slip between the iris unit and the guide pole. This is to obtain the sliding of the unit.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a lens barrel of an embodiment of the present invention. In FIG. 1, description of the same components as those of the related art will be omitted. Reference numeral 10 is a regulation guide portion provided on the main body 4.

In FIG. 1, the regulating guide portion 10 is provided on the main body 4 so as to face the meter portion 7a of the iris unit 7.
When the tilting of the iris unit 7 occurs as in the related art, the iris unit 7 contacts the restriction guide portion 10 to restrict the iris unit 7.

[0012]

As described above, according to the present invention, since the regulating guide portion is provided in the main body in order to prevent the iris unit from falling, there is no anxiety element such as stick slip between the guide pole and the bearing of the iris unit, and the The movement can be made smooth and the occurrence of screen vignetting can be prevented.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a conventional lens barrel.

FIG. 3 is a side view showing the collapse of the iris unit in the conventional lens barrel.

[Explanation of symbols]

 1 1st lens unit 2 2nd lens unit 3 3rd lens unit 7 Iris unit 10 Regulation guide part 11 Guide pole

Claims (1)

[Claims] 1. A first group lens unit including a plurality of lenses, a second group lens unit that moves on a telephoto side and a wide angle side, a third group lens unit that is capable of fine adjustment movement in an optical axis direction, and each of the above. A body that supports the lens unit,
A lens unit comprising a frame body, an imaging means, an iris unit that is spring-biased so as to change its position on the telephoto side and the wide-angle side in conjunction with the operation of the second group lens unit, and a stopper thereof, A lens barrel characterized in that a tilt control guide for the iris unit is provided on the main body.