JPH0462044B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] When fusion splicing single-mode optical fibers, core axes are sometimes aligned using a microscope, visual inspection, or TV camera. .

The present invention relates to a single mode optical fiber fusion splicer, particularly to a microscope portion.

[Prior Art] In FIG. 3, reference numeral 10 denotes a base, on which a support 12 stands, and a plate-shaped stand 14 is horizontally mounted on the support. Mounted on the table 14 are a V-groove block 16 that can be finely adjusted in the horizontal direction (x direction) and vertical direction (y direction), an optical fiber support device 18, and the like.

A control device 20 (V-groove block 1
6), which are covered with a case 22.

The microscope 26 is mounted on a stand 24 that stands upright on the base 10 and is positioned directly above the V-groove block 16. Note that the microscope used in the fusion splicer has one objective lens and one eye lens, and their optical axes are aligned in a straight line. It has a very simple structure. The position of this microscope 26 is not fixed, but needs to be adjusted as follows.

First, when aligning the core in the horizontal direction, the microscope 26 must be positioned exactly above the light from the light source 32 passing through the optical fiber 30 in the x direction, as shown in FIG. The microscope 26 also has an optical fiber 30 in the y direction.
must be in a position where the core of the image is in focus.

Next, when aligning the core in the vertical direction, the microscope 26 is positioned directly above the light from the light source 34, which is reflected in the y direction by the mirror 36 after passing through the optical fiber 30 in the x direction. There must be. Further, the microscope 26 has an image 3 of the optical fiber 30.
It must be in a position where the 0' core is in focus.

Therefore, the position of the microscope 26 needs to be adjusted several times.

[Problems to be Solved by the Invention] When adjusting the position of the microscope 26, it is difficult to adjust the position if the microscope 26 is heavy. In particular, as shown in FIG. 3, a TV camera 27 is fixed to a microscope 26, the image is analyzed by a processor 28,
9 to automatically adjust the position of the microscope 26, the microscope 26 must be moved simultaneously with the TV camera 27. If this happens, the inertia will become even greater, making it difficult to start and stop the engine smoothly. Furthermore, the output of the fine adjustment device 29 must also be increased.

This invention aims to solve the above problem.

[Means for solving the problem] As shown in FIG. 1, the lens barrel 75 of the microscope 74 is separated into an upper lens barrel 76 and a lower lens barrel 78, and only the one of them is connected to the objective lens 77. It is characterized by being able to be finely adjusted in both the x and y directions.

[Example] An example in which a microscope is housed in a case will be described. However, as shown in FIG. 3, the present invention can also be applied when the microscope is placed on top of the case.

In FIG. 1, reference numeral 40 denotes a base on which, for example, four pillars 42 are erected, and a plate-shaped stand 44 is horizontally mounted on the base.

From the stand 44, two elongated plate-shaped supports 46
are lined up and hung at appropriate intervals (however, only one is shown in the drawing; the other is overlapping it and cannot be seen). A microscope 7 is attached to this support material 46.
4 is attached via a fine adjustment device 47, which will be described below.

That is, from each support member 46, each rod 4
8 is made to protrude horizontally, and a rectangular block-shaped horizontally movable member 50 is slidably attached thereto. 52
is a spring. A thick plate-shaped pedestal 54 is fixed on the horizontally movable member 50 so that it moves horizontally together with the horizontally movable member 50.

The two support members 46 are connected by a horizontal plate 55, and a horizontal fine adjustment screw 57 (for example, the male screw side of a micrometer) is fitted into the female screw 56 fixed thereto, and its tip is attached to the pedestal 54. Let it hit you. Further, a motor 58 is horizontally attached to the horizontal plate 55. The rotation of the motor 58 is transmitted to the fine adjustment screw 57 via a gear transmission mechanism 60.

Two rods 62 are placed upright on the pedestal 54,
A thick plate-shaped vertically movable member 64 is slidably fitted therein. 66 is a spring. A fine adjustment screw 69 is fitted vertically into a female screw 68 fixed to the pedestal 54 so that its upper end abuts against the vertically moving member 64. The motor 70 is mounted vertically on the pedestal 54. The rotation of the motor 70 is transmitted to the fine adjustment screw 69 via a gear transmission mechanism 72.

On the other hand, the lens barrel 75 of the microscope 74 is separated into an upper lens barrel 76 and a lower lens barrel 78. An objective lens 77 is connected to the upper barrel 76 . An eyepiece lens 79 is provided in the lower barrel 78 .

Also, a TV camera 80 is connected to the lower lens barrel 78. The TV camera 80 is connected to the rod 81 (the above-mentioned support material 4).
6) and can be manually raised and lowered and fixed in a predetermined position. Note that when the TV camera 80 moves up and down, the optical tube length of the microscope 74 also changes.
The size of the TV image also changes.

Then, the upper lens barrel 76 is attached to the vertically movable member 64.
Fix only.

As described above, when the fine adjustment screw 57 rotates, the upper lens barrel 76 moves in the horizontal direction (x direction) via the pedestal 54, the rod 62, and the vertically moving member 64.

Also, when the fine adjustment screw 69 rotates, the vertically moving member 6
4, the upper lens barrel 76 moves in the vertical direction (y direction).

82 is a V-groove block, which is equipped with a fine adjustment mechanism (not shown) in the x and y directions. 84 indicates an optical fiber.

86 is a light source, and the light is transmitted through bundle fiber 88
through it and hit the optical fiber 84 from right side. In the past, two light sources were used as shown in FIG. 4, but in this case only one light source is used. However, this has no direct relation to the present invention.

90 is a mirror, and the arm 92 attached to it so as not to get in the way during spark discharge.
At the same time, it is possible to retreat on the slope of the platform 93 to the position indicated by the imaginary line.

94 is an electrode.

[Function] An example of automatic adjustment using the TV camera 80 will be explained (FIG. 2).

- Horizontal alignment of the core: A portion of the light emitted from the light source 86 and guided to the bundle fiber 88 is reflected by the mirror 90, passes through the optical fiber 84 in the y direction, and enters the upper barrel 76 ( 85). At this time, the optical fiber 84 is made in advance so that the optical axis of the TV camera 80 coincides with the optical axis.

Note that there are dark areas a on both sides of the optical fiber image 84''.
There are two lines c in the bright area b between them. This line c indicates the position of the core.

If the objective lens 77 is misaligned, the fiber is misaligned on the TV monitor 96, so the processor 95 adjusts the fine adjustment device 47 so that the optical fiber image 84'' is approximately centered. Rotate the motor 58 inside the upper lens barrel 7.
Move only 6 in the x direction. However, the position of the optical fiber image 84'' is not limited to the center because it is desired to use a good part of the imaginary tube of the TV camera 80.
Further, when the microscope 74 is not focused on the core of the optical fiber 84, the width of the dark area a changes, and both edges become particularly blurred (the differential coefficient changes). Therefore, so that they become normal values,
Similarly to the above, a signal is output from the processor 95 to rotate the motor 70 in the fine adjustment device 47,
Only the upper lens barrel 76 is moved in the y direction.

After doing so, the image of the TV camera 80 is analyzed by the processor 95, and the fine adjustment device 98 is operated to adjust the position of the V-groove block 82 to align the core axes.

Since the axis alignment method using the TV camera 80 is not directly related to the present invention, its explanation will be omitted (see Japanese Patent Application No. 58-94454 (Japanese Patent Publication No. 2-34002), etc.).

- Vertical alignment of the core: light source 8 guided by bundle fiber 88
After passing through the optical fiber 84 in the x direction, a portion of the light of 6 is reflected by the mirror 90 in the y direction and enters the microscope 74 (reference 87). This light 87 is slightly shifted in position from the above light 85 in the x direction. Then, the fine adjustment device 4 is adjusted by the processor 95 so that the image 84'' of the optical fiber is centered.
Rotate the motor 58 of 7 to rotate the upper lens barrel 76.
move only in the x direction.

At that time, the lower lens barrel 78 and the TV camera 80
and remain in their original positions, so that one occurs between the optical axes of the objective lens 77 and the eyepiece lens 79.
However, the deviation of the optical axis is usually very small compared to the length of the lens barrel (distance between the objective lens 77 and the TV camera 80) and poses no practical problem. For example, with a lens barrel length of 210mm,
Assuming that the distance between the optical fiber 84 and the mirror 90 is 0.2 mm, the optical axis deviation θ is as follows: θ=tan ⁻¹ 0.2/210=0.05 deg.

Further, the distance between the core of the image 84'' of the optical fiber 84 and the objective lens 77 changes, so that it becomes out of focus.Therefore, as described above, focus is adjusted, and then the axis of the core is aligned.

[Effect of the invention] A microscope 7 in which there is originally one objective lens and one objective lens, and their optical axes are in a straight line.
The lens barrel 75 of No. 4 is separated into an upper lens barrel 76 and a lower lens barrel 78, and only the one connected to the objective lens 77 can be finely adjusted in both the x and y directions. ) The inertia of the moving part is smaller, making adjustment easier. Especially when using a TV camera, there is no need to move the heavy TV camera, making adjustments easier.

(2) In principle, the entire microscope 74 must be moved when aligning in the x direction and when aligning in the y direction.

However, as mentioned above, fiber and mirror 90
The distance between them is very short, and the fiber itself is very thin, so even if you move only the upper lens barrel 76, which has the objective lens attached, the optical axis will not shift from the lower lens barrel that has the objective lens. , very little.

The present invention focuses on this time and simply separates the lens barrel 75 into an upper lens barrel 76 and a lower lens barrel 78 without adding any optical correction to the microscope itself.
Of these, only the one connected to the objective lens 77 is movable.

Therefore, the microscope used is still
It is based on one objective lens and one eye lens, and does not include correction prisms or mirrors.
A very simple structure is sufficient.

Therefore, there is no cost increase in the microscope part, and the necessary purpose can be achieved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of its operation, FIG. 3 is an explanatory diagram of the prior art, and FIG. 4 is an explanatory diagram of its operation. 47...Fine adjustment device, 74...Microscope, 75
... Lens barrel, 76... Upper lens barrel, 77... Objective lens, 78... Lower lens barrel, 79... Eyepiece, 8
0...TV camera, 82...V groove block, 84
...Optical fiber, 86...Light source, 88...Bundle fiber, 90...Mirror.

Claims (1)

[Scope of Claims] 1. An optical fiber is placed in a V-groove block that can be finely adjusted in the x and y directions, and the abutting state is determined by the objective lens and the eye lens, one by one. Using a microscope with their optical axes aligned in a straight line, the horizontal shift is observed using light that passes through the optical fiber in the y direction, and the shift in the horizontal direction is observed using a mirror after passing through the optical fiber in the x direction. In the optical fiber fusion splicing device, the optical fiber fusion splicing device is configured to observe vertical deviation using light reflected in the y direction, and finely adjust the V-groove block based on the observation results, wherein the lens barrel of the microscope is moved upwardly. An optical fiber fusion splicing device characterized in that it is separated into a lens barrel and a lower lens barrel, and only the one of them connected to an objective lens can be finely adjusted in both x and y directions.