JPH06194550A - Coated optical fiber and its coloring method - Google Patents

Abstract

PURPOSE:To obtain a coated optical fiber having a colored layer by which many coated optical fibers are surely identified. CONSTITUTION:A colored layer 2 is made unequal in thickness so that at least one thin-film part 3 is provided in the circumferential direction to constitute a coated optical fiber. At least a part of the periphery of the coated optical fiber is arranged close to the inner wall of a die passing hole, the coated optical fiber is passed through the hole, and a colorant is supplied to the hole to coat the coated optical fiber. The coated optical fiber is colored in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber core wire,
In particular, the present invention relates to an optical fiber core wire having a colored layer with uneven thickness for identifying the optical fiber core wire, and a coloring method thereof.

[0002]

2. Description of the Related Art In the field of optical fiber communication, a multi-core cable such as a pipe core wire or a tape core wire having a structure in which a large number of optical fiber strands are bundled in one cable is being used as the amount of information transmitted increases. It is supposed to be used. Different signals are input to and output from the individual optical fibers included in these multi-core cables according to their purposes. Therefore,
Incorrectly connecting these optical fibers can disrupt the signal, rendering it useless or erroneous. Therefore, it is necessary to surely identify each optical fiber.

Conventionally, the identification of this optical fiber cable has been
The color of the colored layer coated on the outer circumference of the optical fiber core is used. As the coloring method, generally used is a method of providing a colored layer made of an ultraviolet curable ink or a thermosetting ink on the outer periphery of an optical fiber core wire coated with a resin such as nylon after the drawing step. Specifically, the colored layer is formed using, for example, a device as shown in FIG. Reference numeral 6 in the drawing denotes a die, and the colorant 5 made of an ultraviolet curable ink is supplied from a resin supply port 7 provided on the upper portion of the die 6. A resin supply tube 20 is connected to the resin supply port 7, and the resin supply tube 20 is connected.
Communicates with a colorant tank (not shown). That is, the colorant 5 is supplied from the tank to the die 6 through the resin supply tube 20. The die 6 is provided with a penetrating fiber insertion hole 8. When the optical fiber core wire 1 is passed through the insertion hole 8, the coloring agent 5 is applied to the outer peripheral surface of the optical fiber core wire 1. Will be. At this time, the central axis of the optical fiber core wire 1 passing through is arranged so that the central axis of the insertion hole 8 is aligned, and therefore, the outer circumference of the optical fiber core wire 1 has a uniform film thickness. Colorant 5 is applied. The optical fiber core wire 1 to which the coloring agent 5 is applied continues to pass through the ultraviolet irradiation device 9 and is irradiated with ultraviolet rays, and the applied coloring agent 5 is cured to form the colored layer 2.

The optical fiber core wire on which the colored layer is formed in this manner has a sectional structure as shown in FIG.
That is, the colored layer 2 having a uniform thickness is formed around the optical fiber core wire 1. However, when a colored layer having such a uniform thickness is formed, it can be colored only in a single color determined by the color of the colorant used. The colors of the colorants generally used for identifying the optical fiber core are about 10 at most, and if other colors are used, the distinction from other colors becomes unclear. Therefore,
The number of optical fiber cores that can be identified by the color of the colored layer is also
It is limited to about 10 at most. Therefore, when a high degree of information transmission is performed using a larger number of optical fibers, there is a problem that it is difficult to distinguish between the fibers.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to obtain an optical fiber core wire having a colored layer which can surely identify a large number of optical fiber core wires, and a method of coloring the same. To provide.

[0006]

This problem can be solved by an optical fiber core wire provided with an uneven thickness so that the colored layer provided on the outer periphery has at least one thin film portion in the circumferential direction. . The present invention will be described in detail below. FIG. 1 is a sectional view showing an embodiment of the optical fiber core wire of the present invention. In the figure, reference numeral 1 is an optical fiber core wire, and the colored layer 2 is coated around the optical fiber core wire 1. This colored layer 2 has one thin film portion 3 in its circumferential direction.
And has one thick film portion 4 and has an uneven thickness. This thin film portion 3 is hardly colored with a film thickness of 0.5 μm or less, and whether the surface of the optical fiber core wire 1 is almost exposed,
It is assumed that the surface is a portion coated with a thin film that can be visually recognized from the outside, and the thick film portion 4 has a film thickness of 2.0 μm or more and is clearly colored. That is, the appearance of the optical fiber core wire is such that an uncolored portion is formed linearly in the longitudinal direction of the fiber on a part of the outer circumference of the colored fiber core wire.

Next, a method of coloring such an optical fiber core wire will be described. This coloring method is basically the same as the conventional coloring method, and the coloring layer is formed using the apparatus shown in FIG. However, in the present invention, a part of the outer periphery of the optical fiber core wire 1 passing through is arranged close to the inner wall of the insertion hole 8, and another part is arranged apart from the inner wall of the insertion hole 8. ing.

This arrangement will be described with reference to the cross section at the die outlet 6a. As shown in FIG. 2, the inner wall of the insertion hole 8 of the die 6 and the outer peripheral surface of the optical fiber core wire 1 are close to each other at the bottom in FIG. In addition to being arranged, they are arranged apart from each other at the top. Then, with such an arrangement, the colorant 5
When is applied, the uncured thin film portion 13 is formed in the portions arranged close to each other, and the uncured thick film portion 14 is formed in the portion arranged in a spaced manner. Here, the closely arranged portion means that the inner wall of the insertion hole 8 of the die 6 is in contact with the outer peripheral surface of the optical fiber core wire 1 or 1.
The parts are arranged at intervals of 0 μm or less, and
The separated portion means a portion in which the inner wall of the insertion hole 8 of the die 6 and the outer peripheral surface of the optical fiber core wire 1 are arranged with a gap of 2.0 μm or more. This uncured thin film part 1
3 and the uncured thick film portion 14 are coated with the colorant 5 so that the optical fiber core wire 1 continues to be irradiated with the ultraviolet ray irradiation device 9
As it passes through the inside and is irradiated with ultraviolet rays, the applied coloring agent 5 is cured to form the uneven colored layer 2. Further, this optical fiber core wire is wound around a roller (not shown).

In such an optical fiber core, the uncolored thin film portion 3 and the colored thick film portion 4 are formed in the same manner as the two-color strip printing in the longitudinal direction of the fiber. Become. Therefore, by adding a conventional one that is uniformly colored, two types of distinguishable colored layers can be obtained with the same color ink. That is, it is possible to provide the identifiable colored layer on the optical fiber cores whose number is twice the number of colors of the ink used.

In the above description, an example having a colored layer having one thin film portion and one thick film portion was described, but the shape of the optical fiber core wire of the present invention is not limited to this. For example, as shown in FIG. 5, an elliptical insertion hole 8
The inner wall in the minor axis direction is arranged close to the outer peripheral surface of the optical fiber core wire 1, and the inner wall in the major axis direction of the insertion hole 8 is arranged apart from the outer peripheral surface of the optical fiber core wire 1. When the colorant 5 is applied and cured using a die 6 having a size that is large, two thin film portions formed in the minor axis direction of the ellipse and two thick film formed in the major axis direction of the ellipse. The portions are alternately arranged to form a colored layer having an uneven thickness.

Further, when a die 6 having an insertion hole 8 having an inner wall having a plurality of protrusions formed along the longitudinal direction of the insertion hole as shown in FIG. 6 is used, the inner wall of the insertion hole 8 is used. In the concave portion, the inner wall and the outer peripheral surface of the optical fiber core wire 1 are arranged apart from each other, and in the convex portion of the inner wall of the insertion hole 8, the inner wall and the outer peripheral surface of the optical fiber core wire 1 are arranged close to each other. ,
After applying and curing the colorant, a colored layer having a shape in which four thin film portions and four thick film portions are alternately arranged is formed. In addition to this, by using a die having an insertion hole having a polygonal cross section such as a triangle or a quadrangle, or a die having an insertion hole having an inner wall having more irregularities than that shown in FIG. It becomes possible to form various kinds of colored layers.

As the optical fiber core wire used here, a generally used one can be used as it is. For example,
After the drawing step, an optical fiber core wire coated with nylon or silicone resin is used. Further, the optical fiber element wire that has finished the drawing step, the colored layer of the present invention is formed,
After that, resin coating may be performed to form an optical fiber core wire or an optical fiber tape core wire.

As the colorant, an ink generally used for coloring the optical fiber core wire can be used, and the kind of the color is not limited. Further, although the ultraviolet curable ink is used in the above example, a thermosetting ink or the like may be used, and in that case, the ultraviolet irradiation device in FIG. 3 is used as a heat treatment device such as an oven. However, in order to shorten the curing time and improve the productivity, it is preferable to use an ultraviolet curable ink.

The thickness of the colored layer should be such that the colors of the thin film portion and the thick film portion can be surely discriminated from each other. However, if the difference in film thickness between the two becomes large, distortion will occur and the strength of the fiber itself will be weakened. Therefore, the difference in film thickness between the thin film part and the thick film part is 1 μm.
It is preferably within the range of 10 μm. Hereinafter, the present invention will be described with reference to specific examples, but the content of the present invention is not limited thereto.

(Example 1) A blue colored layer was formed on the outer circumference of an optical fiber core wire having an outer diameter of 250 µm by using an apparatus as shown in Fig. 3 equipped with a die having a circular insertion hole having an inner diameter of 270 µm. . First, blue-colored ultraviolet curable ink was charged into the tank, and the optical fiber core wire was passed through the die. At that time, the lower end of the optical fiber core wire was arranged so as to be in contact with the lower end of the inner wall of the die, and the upper end of the optical fiber core wire was arranged at a distance of 0.5 μm from the upper end of the inner wall of the die insertion hole. Further, the optical fiber core wire coated with the coloring agent from the die is irradiated with ultraviolet rays by a UV lamp to be cured, and an optical fiber having an uneven thickness colored layer having one thin film portion and one thick film portion. I got the core wire. The colored layer of the obtained optical fiber core wire had a thickness of 8 μm in the thickest part and 0.2 μm in the thinnest part, and both colors could be clearly distinguished.

(Embodiment 2) Major axis 270 μm, minor axis 253
An outer diameter of 250 μm is obtained by using an apparatus as shown in FIG. 3 in which a die having an elliptical through hole as shown in FIG.
The optical fiber of (1) was placed so that its central axis coincided with the central axis of the ellipse of the die insertion hole, and was passed through to form a blue colored layer. The other conditions were the same as in Example 1. As a result, an optical fiber core wire having an uneven colored layer having two thick film portions (thickness 5 μm) and two thin film portions (thickness 0.5 μm) was obtained. The colors of the thick film portion and the thin film portion could be clearly distinguished.

[0017]

According to the optical fiber core wire of the present invention, the colored layer provided on the outer periphery of the optical fiber core wire is unevenly thickened so as to have at least one thin film portion in the circumferential direction, and the thin film is formed. Since the color of the portion and the thick film portion can be clearly discriminated, it becomes the same as that in which the fiber is printed in the longitudinal direction.
Therefore, it is possible to form two or more kinds of distinguishable colored layers using the same colorant, and it is possible to reliably distinguish a large number of optical fibers. Further, such a method for forming a colored layer can be easily carried out by using the apparatus used in the conventional coloring step as it is, only by changing the passing position of the optical fiber, or by appropriately changing the dice. Since it is possible, it is an extremely advantageous method in terms of cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of an embodiment of an optical fiber core wire of the present invention.

FIG. 2 is a cross-sectional view illustrating an example of a method for coloring an optical fiber according to the present invention.

FIG. 3 is an explanatory diagram of an apparatus used for coloring an optical fiber core wire.

FIG. 4 is a cross-sectional view illustrating an example of a method for coloring an optical fiber according to the present invention.

FIG. 5 is a cross-sectional view illustrating an example of a method for coloring an optical fiber according to the present invention.

FIG. 6 is a sectional view showing a structure of a conventional optical fiber core wire.

[Explanation of symbols]

1 ... Optical fiber core wire, 2 ... Colored layer, 3 ... Thin film part, 4 ...
Thick film portion, 5 ... Colorant (before curing), 6 ... Dice, 7 ... Resin supply port, 8 ... Insertion hole 9 ... UV irradiation device, 13 ... Uncured thin film portion, 14 ...
Uncured thick film part

Claims (2)

[Claims] 1. An optical fiber core wire, wherein a colored layer provided on the outer periphery is provided with uneven thickness so as to have at least one thin film portion in the circumferential direction. 2. The optical fiber core wire is passed through the die insertion hole while at least a part of the outer peripheral surface of the optical fiber core wire is arranged close to the inner wall of the die insertion hole, and the coloring agent is passed through the die insertion hole. And a coloring agent is applied to the outer peripheral surface of the optical fiber core to supply it to the optical fiber core.