JPS5961805A - Lens barrel - Google Patents

Abstract

PURPOSE:To facilitate a position adjustment of a focusing point lens in an optical-axis direction by adjusting the relative position of the 2nd barrel in the optical-axis direction by the rotation of an eccentric pin, and fixing the eccentric pin by a fixing means in the adjusted state. CONSTITUTION:A moving lens barrel 10 is fitted slidably around a fixed lens barrel 9 and a lens holding part 10a is provided to the inner circumferential surface of this moving lens barrel 10. The focusing point lens 11 is clamped fixedly between the lens holding part 10a and a lens presser frame 12. The moving lens barrel 10 is provided with a rotation-angle specifying pin 13 which enters the notch part 9a of the fixed lens barrel 9 and this pin 13 abuts on the fixed lens barrel 9 to restrict the rotation of the moving lens barrel 10. The moving lens barrel 10 is provided with a cam groove 14 and a cam follower 15 fitted therein is fixed to the fixed lens barrel 9 by a fixing screw 16 which pierces a through hole formed at a distance apart from the center of the cam follower; and this screw 16 is necessarily loosened to rotate the cam follower around the center of the screw 16.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a lens barrel for a video camera or the like.

Conventional structure and its problems Conventionally, the focusing mechanism of a lens barrel has generally used a helicoid screw provided in a fixed barrel and a movable barrel to extend the lens. This will be explained using figures. a helicoid inner cylinder (1) which is a fixed lens barrel;
A helicoid outer tube (2), which is a movable lens barrel, is fitted, and the helicoid outer tube (2) is equipped with a lens holding frame (4) that holds a focusing lens (3), and this lens holding frame ( 4
) is attached to the helicoid outer cylinder (2) so that it can be finely adjusted in the direction of the optical axis (6) by means of a threaded part (5) I formed on its outer peripheral surface and the inner peripheral surface of the helicoid outer cylinder (2). ing. A rotation angle regulating pin (7) that fits into the notch (1a) of the helicoid inner barrel (1) is implanted in the helicoid outer cylinder (2). By contacting the inner cylinder (1), the rotation angle of the helicoid outer cylinder (2) is regulated. Also, helifit outer cylinder (2)
Distance numbers are engraved on the rear end (2a) of the outer peripheral surface of the lens, and the focusing distance can be displayed using the index line (8) formed on the outer peripheral surface of the helicoid inner cylinder (1). Yes, when assembling the lens barrel, rotate the lens holding frame (4) and move the focusing lens (3) in the direction of the optical axis (6) so that the displayed distance number and the actual focusing distance match correctly. It is configured to be adjusted back and forth.

However, in such a conventional lens barrel, a lens holding frame (
4) is provided at °C, the outer diameter of the lens barrel becomes larger compared to the case where the focusing lens (3) is directly attached to the helicoid outer cylinder (2), and the front and back position of the lens holding frame (4) also increases. Screws are used for adjustment, and if the screw precision is poor, the lens will become decentered, so there is a problem in that highly accurate screw machining is required.

Purpose of the Invention The present invention solves the above-mentioned conventional drawbacks, and aims to provide a lens barrel in which the outer diameter of the steel part can be reduced, and in addition, the eccentricity of the lens can be prevented without performing high-precision screw processing. do.

Structure of the Invention In order to achieve the above object, the lens barrel of the present invention includes a first cylindrical body and a second cylindrical body having a lens holding portion and slidably fitting into the first cylindrical body. a rotation angle regulating means for regulating the rotation angle of the second cylindrical body; a groove formed in the second cylindrical body and inclined at a constant angle with respect to the circumferential direction thereof; An eccentric bottle rotatably fitted into the groove, and a fixing means for fixing the eccentric bottle to the first cylindrical body in a state where the eccentric bottle is prevented from rotating, and by rotating the eccentric bottle, the The relative position of the second cylindrical body in the optical axis direction is adjustable, and the eccentric bin is fixed by the fixing means in the adjusted state.

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

In FIGS. 2 and 8, (9) is a fixed lens barrel,
A movable set IQ is slidably fitted onto the fixed lens barrel (9), and a lens holding #
(tOa) is provided protrudingly. C11) is a focusing lens, and this focusing lens Qη is attached to the lens holding portion (1
0a) and lens holding frame 4 and fixed to C
There is. The movable lens barrel (101 is the fixed mirror 11h (o)
A rotation angle regulating pin ring that fits into the notch (9a) is installed, and when this rotation angle regulating pin 4 comes into contact with the fixed lens barrel (9), the movable lens barrel 0 (I) The rotation angle is regulated.A cam groove α◆ is formed in the movable mirror &FilC1O, and an eccentric cam follower (T) is fitted into this cam groove Q4.
is caused by the cam follower fixing screw Q passing through the through hole formed at a position away from the center of the fixed mirror Jl.
lii (9), and the cam follower fixing screw a
By loosening the lock, the cam follower can be rotated around the fixing screw of1. In this way, the cam follower is fixed to the fixed lens barrel (9) with the cam follower fixing screw QQ.
This eccentric cam follower Q4 fits into a cam groove α◆ carved in the circumferential direction of the movable lens barrel and inclined at a predetermined angle. 4II By rotating the lens barrel QQ, the focusing lens Qυ moves in the optical axis Qη force direction while rotating. Distance numbers are engraved on the outer peripheral surface of the rear end (10b) of the movable lens barrel C11), and the distance numbers and b (fixed mirror 1)
1fil (9) The focusing distance can be displayed with the index line Q barrel formed on the outer peripheral surface. In addition, the range of the distance number engraving matches the notch range of the notch part (9a) of the fixed lens barrel (9), and the rotation angle regulating bin o3 is in contact with the fixed lens barrel (9). Sometimes, the distance number on the outer circumferential surface of the moving body C1 (for example, ■, 10.5.8.2.1.5
) The numbers at both ends (Oo or 1.6) are the index line (to)
matches.

Next, the procedure for adjusting lens assembly will be explained. After assembly, first move the movable lens barrel by 1g1 until the distance number ■ matches the index line (to). In this state, the position of the optical axis αη of the focusing lens Q]) is adjusted in the force direction using a collimator, etc., but the focusing lens 01) is
Since it is integrally fixed to 1, it fits into the cam groove α°.
By rotating the eccentric cam follower O [9 in C, the movable lens barrel Q [) is moved back and forth in the direction of the optical axis (171).
Insert a screwdriver etc. into the hole and turn it. At this time, if the eccentric cam follower ◇Q is rotated while the rotation angle regulating bin (+a and the fixed mirror &I (9) are in contact with each other,
The position of the distance number ■ and the index line (to) will not deviate. After adjusting the ■ position of the focusing lens 0υ, fix the eccentric cam follower mark α with the cam follower fixing screw αQ. There are relief parts (14a) (1
4b) is provided to prevent the eccentric cam follower αQ from coming into contact with the end wall of the cam groove α◆.

Effects of the Invention As described above, according to the present invention, the position of the focusing lens in the optical axis direction can be adjusted by rotating the eccentric pin within the groove. Since no frame is required, the outer diameter of the lens barrel can be reduced, and high-precision screw machining is not required, resulting in easy machining, which can reduce costs and improve performance. Further, the position of the focusing lens in the optical axis direction can be adjusted very easily.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a conventional lens barrel, FIG. 2 is a cross-sectional view of essential parts of a lens barrel according to an embodiment of the present invention, and FIG.
The reason is that this is a plan view of the main parts of the lens barrel. (9)... Fixed lens barrel (first barrel), 0Q... Movable barrel (second barrel), (10a)... Lens holding part,
α rule...Rotation angle regulation pin, 04...Cam groove (groove)
, On... Eccentric cam follower (eccentric pin), (1...
Cam follower fixing screw. Agent Yoshihiro Morimoto

Claims (1)

[Claims] 1. A first cylindrical body, a second cylindrical body having a lens holding portion and slidably fitting into the first cylindrical body, and regulating the rotation angle of the second cylindrical body. a rotation angle regulating means, and the second
a groove formed in the cylindrical body at a predetermined angle with respect to the circumferential direction; an eccentric pin fitted into the groove for rotation; and fixing means for fixing to the cylindrical body, the relative position of the second cylindrical body in the optical axis direction can be adjusted by rotating the eccentric bin, and in the adjusted state, the eccentric bin is fixed by the fixing means. Lens barrel configured to be fixed.