JPS58100806A - Zoom lens barrel of fiberscope - Google Patents

Abstract

PURPOSE:To obtain a zoom lens barrel which is suitable for incorporating it to the tip part of a fiberscope, by providing a gear ring being a zoom driving means, irrespective of movement of a zoom ring in the optical axis direction. CONSTITUTION:When a wire 12 is drawn, a straight ring 4 moves to the right side against a compression spring 11, and a zoom ring 3 also moves as one body. A key member 3e moves in a key groove 7b, lens groups G1-G3 move to the right side, the lens group G3 approaches the end face of an image fiber 8, and when the wire 12 is loosened, the lens group G3 recedes in the distance by the compression spring 11, and focusing is executed. Subsequently, when a pulley 14 is rotated by operating a wire 15, a gear ring 7 meshed with a small gear 13 rotates, the zoom ring 3 rotates through the key member 3e and the key groove 7b, pins 5a, 6a go straight along straight grooves 4a, 4b, lens rings 5, 6 move in the optical axis direction, and the zoom operation is performed. Accordingly, this zoom lens barrel is suitable for incorporating it to the tip of a fiberscope.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an optical** device using an image fiber, a so-called fiberscope zoom lens + iiiMi
Regarding K.

A normal zoom lens has a zoom ring and a focusing ring, and by operating these rings, the objective of f-times 1 focusing is achieved. But inside a thin pipe.

In addition, for fiberscopes that are inserted into narrow spaces to observe the inside, the outer diameter must be kept as small as possible, making it impossible to use a lens barrel with the same structure as a conventional zoom lens.

Therefore, it is conceivable to provide a lens with a fixed focus at the tip end of the fiber (on the side of the object to be observed) and to arrange a zoom lens at the rear end side of the fiber V. -j in such a configuration.

Although there is certainly an advantage in being able to reduce the outer diameter of the fiberscope, there is also the disadvantage that the image becomes noticeably blurred due to the fact that the zoom lens is placed at the rear end of the fiber. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to obtain a zoom lens barrel that has a smaller outer diameter and is suitable for being incorporated into the distal end of a fiberscope.

Next, the present invention will be explained with reference to figures showing examples.

On the observation object side of the outer cylinder 1 (left end in the figure).

A window glass 2 is provided to shield the outside and the inside of the outer cylinder 1. Inside this outer cylinder 1, a zoom ring 6 having cams tll15m and 5b for R-multiplying is installed inside the outer cylinder 1.
K that can be rotated freely inside.

and is fitted so as to be slidable in the direction of the optical axis l. Further, inside the zoom #16, a rectilinear ring 4 for a focus plate is provided, and its tip (as shown in the figure) is provided.

Lens group G1 is fixed on the left side).

Inside the linear ring 40, there is a lens ring 5 that holds the lens group G2 and is slidable in the direction of the optical axis l, and a lens #G.
3, the optical axis l passes through the straight hole 4a provided in the straight ring 4 along the optical axis 1 direction and engages with the cam groove 6a, and the pin 6a moves straight along the optical axis l direction f14. The cam $5b is engaged with the cam $5b through a straight hole 4b provided therein. Furthermore, on both end surfaces of the zoom ring 5.

Flange g3. Slightly protruding inward. ), 3d are formed, and the linear ring 4 is inserted between these flange parts 3o, 3d.

In addition, in FIG. 9, the wall thickness is thinner from the middle to the right side of the outer cylinder 1, and a gear ring 7 having a bevel gear 7a formed on the end face is provided between this area and the zoom ring 6. ing. This gear ring 7 is rotatable within the outer cylinder 1 about the optical axis l. A key groove 7b extending in the direction of the optical axis 1 is provided in a part of the inner wall of the gear ring 7, and engages with a key member 5 protruding from the zoom [5]. In addition, the gear ring 7 is the outer cylinder 1.
On the other hand, at least 1, sliding to the left in the figure is prevented. Above key groove 7b, key part 50K
[Thus, 70 rotations of the gear ring are transmitted to the zoom ring 5,
Rotate as one. On the other hand, the image fiber 8 is fixed to the outer tube 1 by a support member 9 so as to be coaxial with the center of the outer tube 1, that is, the optical axis l. Note that the portion from the end surface of the image fiber 8 to the fixed portion of the support member 9 is covered by a tube 9a. Further, a fixed cylinder 10 is fixed to the support member 9 to support the fitting portion 40 of the linear ring 4 having a reduced diameter. A key member 11Ja protrudes from a part of the inner wall of the fixed cylinder 10, and engages with a straight line #4a extending in the optical axis l direction from a part of the outer wall of the fitting part 4o. The lock member 10a and the linear groove 4d prevent rotation of the linear ring 4 about the optical axis l. Also, inside the fitting part 4o.

A flange 4, which has a hole through which the holder 9a passes, is fixed. A compression spring 11 is provided between the flange 4 and the support member 9 so as to allow the tube 9a to pass therethrough.

This compression spring 11 acts to always urge the rectilinear ring 4 from the support member 9 toward the window glass 2 side.

One end of a wire 12 for focus adjustment is fixed to the flange 4sK, and the other end of this wire 12 is fixed to the support member 9.
It is connected to an operating device (not shown) through the.

The fixed cylinder 10 also has a shaft 10 in the space between it and the inner wall of the outer cylinder 1.
b is provided protrudingly.

This shaft 10b is rotatably engaged, and -Nk
Small tooth 1 meshing with bevel gear 7a of ring 7! t15 and a pulley 14 are provided. This small gear 1'5 and the pulley 14 are integrally formed, and by operating the zoom wire 15 that is passed around the pulley 14, the small gear 1'5
rotates. This gear ring7. The small tooth IL13° and the pulley 14 constitute a zoom driving means.

Although not shown, the rear of the outer cylinder 1 etc. (in the figure, the right l1
ll) is connected to a flexible pipe.

Next, the operation of this embodiment will be explained. First of all, focus
dI4 adjustment, so-called focusing, will be explained.

Focusing is performed by pulling or loosening the wire 12 in the direction of the arrow.

Now, if we pull the wire 12, the pressure spring 11
7 lunges 4s against the urging force of.

Inset part 40. The straight a ring 4 including the a-ring moves to the right side in the figure. At this time, the key member tOa moves in the straight groove 4d in one direction of the optical axis &
C sliding, straight ring 4.

There is no rotation around the optical axis l. This straight fiJI
As the I4 moves, the zoom ring 3 also moves together. At this time, the key member 6e slides within the key 7b. Therefore, the lens 1pP(h, ()2).

Gs moves as one to the right side in the figure, and the lens group ()
The distance between δ and the end face of the image fiber 8 is made small. Furthermore, when the tensile force of the wire 12 is loosened, the biasing force of the compression spring 11 causes the rectilinear ring 4. The zoom ring 6 is integrated.

Move 1M11K to the left in the figure. Therefore, the lens groups (J, G2, Gs) move to the left as a unit.

The distance between the lens WaS and the end face of the image fiber 8 is increased. In this way, a group of wires Gl, ()
2 and Gl can be moved together to form an image of the object to be observed on the end face of the image fiber 0.

Next, the operation of changing the focal length, that is, the zoom operation will be explained. The zoom operation.

This is done by rotating the pulley 14 by manipulating the wire 15. This rotation of the pulley 14 causes the gear ring 7 meshed with the small gear 13 to rotate around the optical axis l. This rotation.

The power is transmitted to the zoom ring 6 through the keyway 7b and the key member 30, and the gear ring 7 and the zoom ring 6 rotate together. At this time, the straight ring 4 is prevented from rotating by the key member 1Oa and the straight groove 4d, so that the zoom ring 6 is not inserted into the straight ring 4 and the outer cylinder 1.
rotate between. Therefore, depending on the shape of the cam groove 6&, the pin 5a moves in the optical axis 1 direction along the straight hole 4aK, and the pin 6a also moves according to the shape of the cam groove 5b.
θ moves. Therefore, the Luns ring 5. Second lens ring 6
move each other in a predetermined direction in the direction of the optical axis l in order to continuously vary the focal length. in this way.

A variable power lens m configured by operating the wire 15
Only G21 Gg moves in one direction of the optical axis.

My appearance due to the focusing and zooming operations as described above is successively monitored by an observation device (eyepiece, ITV, etc.) K provided at the other end (not shown) of the image fiber 8.

9 In the present invention, the imaging optical system is, as in the embodiment, in addition to the so-called six-group structure consisting of lens groups +) Two lens groups were provided. 4m
- configuration, etc., but it does not go beyond the point that it is more compact to have a 6-group configuration as in the embodiment.

As described above, in the present invention, the gear ring 7 serving as the zoom driving means is connected irrespective of the movement of the zoom ring 5 in the optical axis direction.
and zoom ring 6 can move together in the optical axis direction. Therefore, during focusing, lens group G2. G5 does not change at all,
The entire imaging optical system can be moved, making it much more compact than a conventional zoom lens in which only the focusing lens is moved.

In addition, as shown in the embodiment, the linear ring 4 has a compression spring 11
is always biased toward the tip of the fiberscope. Therefore, focusing can be done by adjusting the tensile force of the wire 12, and there is also the advantage that the operability of the flexible fiberscope is improved.

[Brief explanation of the drawing]

The figure is a sectional view of a zoom lens barrel according to an embodiment of the present invention. [Clarification of symbols of main parts] 1. Outer cylinder 5. Zoom ring 4. Straight ring 8. Image fiber applicant 2. Nippon Kogaku Kogyo Co., Ltd.

Claims (1)

[Claims] In a fiberscope that transmits observation data using an image fiber. A rectilinear ring that can move the optical system including the variable magnification lens in the optical axis direction for focus adjustment; and a rectilinear ring that is movable in the optical axis direction to adjust the focus; Possible *Kii An outer cylinder that accommodates a zoom ring and a knee zoom ring movably in the optical axis direction and holds the end face of the image fiber in alignment with the optical axis; and an outer cylinder that provides rotational force to the zoom ring. A zoom lens barrel for a fiberscope, characterized in that it is equipped with a driving means.