JPH08201670A - Method of manufacturing optical fiber ribbon - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a method for manufacturing an optical fiber ribbon, which can stably form a tape coating of about several tens of μm on the outer side in the width direction of the optical fiber ribbon. And [Structure] A step of manufacturing an optical fiber tape core wire in which an optical fiber element wire 1 is integrated into a tape shape, and a temperature of a UV curable resin 16 cured by forcibly cooling the optical fiber tape core wire. And forcibly lowering the optical fiber tape core wire through the opening of the die 6b filled with the ultraviolet curable resin 17 in a fluidized state, thereby allowing the ultraviolet curable fiber core wire to be cured outside the optical fiber tape core wire. Resin 1
7 is applied, and a step of irradiating the ultraviolet curable resin 17 with ultraviolet rays to cure the resin 17 to produce an optical fiber tape core wire in which the thickness of the coating in the width direction is thicker than the thickness in the thickness direction. Is equipped with.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical fiber ribbon, which comprises a plurality of optical fiber strands arranged in a plane and integrated into a tape.

[0002]

2. Description of the Related Art Conventionally, as an optical fiber unit which is effective in constructing a multi-core optical fiber cable, a plurality of optical fiber wires are arranged in a plane, and the periphery thereof is collectively covered and integrated. An optical fiber tape core wire is used. For the coating applied here, an ultraviolet curable resin having excellent productivity because it is rapidly cured by irradiation with ultraviolet rays is used.

The optical fiber ribbon is formed by arranging a plurality of optical fiber strands in a plane and then using a die having an oval opening to form a plurality of optical fibers of highly viscous UV curable resin. It is manufactured by applying it to the outside of the wire and irradiating it with ultraviolet light to cure the applied ultraviolet curable resin.

The conventionally used optical fiber ribbon has an outer diameter of the optical fiber of 250 μmφ, the number of cores of the optical fiber of 2 to 12 and a thickness of 400 μm. As the width of the optical fiber ribbon, it is general that the optical fiber strand diameter × the number of cores + 100 μm, and several tens of μm around the plurality of arranged optical fiber strands.
It is customary to carry out a batch coating with a thickness of.

By the way, in recent years, there is an idea to construct the subscriber line network entirely by optical fibers. In order to realize this concept, adoption of a high-density optical fiber cable having an outer diameter equivalent to that of a conventional optical fiber cable and having a few thousand optical fiber cores in the cable is being considered. In order to construct such a high-density optical fiber cable, the optical fiber element wire is thinned to, for example, an outer diameter of 200 μmφ or less, and the optical fiber tape core wire is multi-coreed to, for example, 16 cores. The thickness of 0.25m
It is necessary to reduce the thickness to about m or less, and studies are underway.

[0006]

However, although the optical fiber wires arranged in a plane are arranged at both ends,
On the outer side in the width direction of the optical fiber ribbon, several tens of μ are provided, as in the currently used optical fiber ribbon.
It is necessary to apply a coating with a thickness of m. This is because the ones arranged at both ends of the optical fiber bare wire are apt to have excessive stress due to an external force acting when the cable is constructed by using the optical fiber ribbon, so that the transmission characteristics are not deteriorated, Moreover, in order to guarantee the strength, it is necessary to apply a coating having such a thickness.

In the conventional method of manufacturing an optical fiber ribbon, there are a method of forming the tape coating with a one-layer coating and a method of forming the tape coating with a two-layer coating. However, by any of the above methods, in the case of a multi-core optical fiber tape core wire using the above-mentioned thin optical fiber element wire, a tape coating of about several tens of μm is provided outside the width direction of the optical fiber tape core wire. Was difficult to form stably.

When the tape coating is formed of a single layer, the width of the die used for applying the tape material is required to form the tape coating of several tens of μm or more at both ends in the width direction of the optical fiber tape core wire. , (Optical fiber strand outer diameter ×
It was necessary to make the length about 100 μm or more larger than the length calculated by the (core number). However, in the case of a multi-core optical fiber ribbon using the thin optical fiber strand as described above, the tape coating on both ends in the width direction of the optical fiber ribbon has a thickness of at most 19 μm. I couldn't get it.

Further, even if the width of the die is expanded to (the outer diameter of the optical fiber strand × the number of cores + 400 μm) for the purpose of compensating for this lack of thickness, the tape coating of both ends in the width direction of the optical fiber ribbon is performed. Is not more than 30 μm, and there is a problem that variations in the thickness of the tape coating become large. Also, if only one side is up to 30 μm
However, even in this case, the other side was only about 15 μm.

Therefore, an object of the present invention is to provide a method of manufacturing an optical fiber ribbon which can stably form a tape coating of about several tens of μm on the outer side in the width direction of the optical fiber ribbon. It is in.

[0011]

In order to achieve the above object, the invention according to claim 1 is a step of arranging a plurality of optical fiber wires in a plane and applying an ultraviolet curable resin at once. And irradiating the ultraviolet curable resin applied to the optical fiber strand with ultraviolet rays to cure the ultraviolet curable resin,
A process of manufacturing an optical fiber tape core wire in which optical fiber strands are integrated into a tape, and by forcibly cooling the optical fiber tape core wire, the temperature of the cured ultraviolet curable resin is forcibly lowered. The process and the process of applying the ultraviolet curable resin to the outside of the optical fiber tape core wire by passing the cooled optical fiber tape core wire through the opening of the die filled with the flowing state ultraviolet curable resin. The gap between the optical fiber tape core wire and the opening is larger in the width direction of the optical fiber tape core wire than in the thickness direction, and the ultraviolet curable resin applied to the optical fiber tape core wire. The UV-curable resin is cured by irradiating it with UV light, and the thickness of the UV-curable resin in the width direction is thicker than the thickness of the UV-curable resin in the thickness direction. And a step of manufacturing the core wire.

It is preferable that the optical fiber ribbon is forcibly cooled by using helium gas.

[0013]

In the present invention, the coating of the ultraviolet curable resin is formed by two layers. Then, the first layer of ultraviolet curable resin is applied and cured, then the optical fiber tape core wire is cooled, and then the second layer of ultraviolet curable resin is applied. Therefore, the ultraviolet curable resin of the second layer can be stably applied, and the tape coating of about several tens of μm can be stably formed on the outer side in the width direction of the optical fiber ribbon.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the same reference numerals are used for the same or corresponding parts in the drawings.

Since a thin optical fiber ribbon is required, the thickness of the tape coating of the optical fiber ribbon is suppressed to about 20 μm. If the thickness of the tape coating in the width direction of the optical fiber ribbon is also about the same, it is not so difficult to form. However, 20 μm only in the width direction of the optical fiber ribbon.
It is difficult to apply a tape coating having a thickness of more than 10 μm because the UV curable resin before curing which has fluidity moves due to surface tension. Therefore, it is conceivable to form the tape coating with a two-layer coating and apply the second layer only in the width direction, but in this case as well, the second layer coating cannot be applied stably.

In such an optical fiber ribbon, the required covering structure is larger in the width direction than in the thickness direction. Therefore, before the tape material is applied by the die and cured in the application of the first layer, the resin of the tape material has a thickness of about 0.24 to about immediately after leaving the die due to its own surface tension.
The elliptical shape of 0.25 mm and the width of about 3.3 mm cannot be maintained. This only increases longitudinal instability when the die shape is changed.

For example, simply comparing the coating thicknesses of the tape material in the thickness direction and the width direction of the optical fiber ribbon, it is about 20 to 25 μm, which is about several tens of μm, which is about double. There is. Therefore, for the optical fibers arranged at both ends, a double coating ratio is required in two directions forming 90 ° on the cross section, but before curing, the shape is not maintained due to the fluidity and surface tension of the tape resin. . When classifying the irregularities of the shape, the tape material that was intended to be attached to both ends had a large gap between the optical fiber wires near the center of the tape instead of at both ends, and the thickness of the coating near the center of the tape. Was found to be partially inflated. Therefore, in order to maintain the arrangement of the optical fiber strands, the coating is
As the layer coating, the arrangement of the optical fiber element wires is mainly maintained by the first layer, and the coating thickness is adjusted by the second layer. In this way, at the stage of applying the second layer, the optical fiber element wires have already been arranged and cured collectively with the tape material resin, so that the arrangement is not disturbed.
Further, after the first layer is cured, the shape of the tape is already formed although it is incomplete, so that the thickness of the coating near the central portion of the tape does not swell.

Since the coating of the tape material of such an optical fiber tape core is intended to be large only in the width direction as compared with the thickness direction, when the tape material and the coating have a one-layer structure. The surface tension causes the fluid resin to move before the resin of the tape material applied by the die is cured. For this reason, it is difficult to form the coating of the tape material with one layer, and it is necessary to mainly coat both end portions after coating and curing the first layer. Also, 2
In order to stabilize the coating in the coating of the first layer (in order to keep the coating thickness constant), the optical fiber element wires are arranged in a plane and the UV curable resin is collectively applied and cured, and then the second layer is applied. Before applying, the tape-shaped optical fiber core wire (semi-finished product of the tape core wire) is forcibly cooled. This stabilizes the coating of the second layer.

The instability of the coating in the coating of the second layer is due to the hardening of the tape material of the first layer. That is,
For curing, UV irradiation is performed, but actually, what is irradiated is also irradiated with light of a thermal radiation component having a wavelength longer than UV, and heat of polymerization reaction is generated during curing. Therefore, after the first layer tape material is cured, the resin of the tape material becomes high in temperature, which causes the wetting or viscosity of the resin to become unstable, and sometimes the application of the second layer tape material becomes unstable. Therefore, after the first-layer tape material is hardened and before the second-layer tape material is passed between the dies, the instability factor can be removed by forcibly cooling (more than natural cooling). preferable. FIG. 1 is a diagram showing an apparatus for manufacturing an optical fiber ribbon according to the present invention.
In FIG. 1, reference numeral 9 indicates a cylinder for forced cooling.

Further, in order to improve the cooling efficiency, when He gas having a high thermal conductivity is used as the cooling gas, the temperature of the tape resin can be further lowered or the forced cooling cylinder 9 can be downsized. More preferable. In FIG. 1, a He gas cylinder 10 is attached to the forced cooling cylinder 9.
Are connected, and He gas is introduced into the forced cooling cylinder 9.

[Embodiment 1] FIG. 1 is a diagram showing the construction of an apparatus for carrying out a method for manufacturing an optical fiber ribbon according to the present invention.

The optical fiber strand 1 used here is formed by coating two layers of urethane acrylate-based ultraviolet curable resin on a single mode optical fiber glass having an outer diameter of 125 μmφ, and an outer diameter of 200 μmφ. is there. Sixteen optical fiber strands 1 are fed from a supply 4, which is equipped with 16 supply reels 2 around which the optical fiber strands 1 are wound, through a supply dancer roller 3 with a tension of about 50 g. The 16 optical fiber strands 1 fed out are arranged in a row using the guide roller 5 for optical fiber strands, and the urethane acrylate-based ultraviolet curable resin supplied from the pressure type resin supply device 7a is a pressure type. It is applied collectively by the application die 6a. The pressure application die 6a has an oval opening. The size of this opening is 3.30 m in the width direction of the optical fiber ribbon.
Similarly, the thickness direction is 0.28 mm. 16
The optical fiber strands 1 of the book are collectively coated with a urethane acrylate-based ultraviolet curable resin when passing through this opening.

The 16 optical fiber strands 1 coated with the urethane acrylate-based UV curable resin all at once are passed through the UV irradiation furnace 8a, and the applied urethane acrylate-based UV curable resin is cured. This optical fiber strand 1 is further passed through a forced cooling cylinder 9 of 1 m length in which He gas at 23 ° C. flows at a flow rate of 5 liters / minute, and is forcibly cooled. Further, the urethane acrylate-based UV-curable resin supplied from the pressure-type resin supply device 7b has an oval opening on the outer circumference of the optical fiber element wire 1 which is coated and cooled as described above. It is applied by the application die 6b. The size of this oval opening is 3.50 in the width direction of the optical fiber ribbon.
mm, and the thickness direction is 0.28 mm. That is, the width direction of the pressure applying die 6b is larger than the pressure applying die 6a by 0.20 mm, and
The gap between the optical fiber ribbon and the opening is larger in the width direction of the optical fiber ribbon than in the thickness direction. The coating of the second layer thus formed is cured by the ultraviolet rays emitted from the ultraviolet ray irradiation furnace 8b.

The optical fiber tape core wire manufactured as described above is the optical fiber tape core wire guide roller 11,
It is wound on the winding reel 15 via the capstan 12, the winding dancer roller 13, and the winding device 14. The production speed of the 16-fiber optical fiber ribbon thus produced is 50 m / min.

The cross section of the manufactured 16-fiber optical fiber ribbon is shown in FIG. That is, the collective coating forming the optical fiber tape core wire is composed of two layers of the inner layer coating 16 and the outer layer coating 17, and the thickness (t in FIG. 2) of the optical fiber tape core wire is 0.25 mm and the width (t). 2w)
Is 3.30 mm. The thickness (d in FIG. 2) in the width direction of the optical fiber ribbon coated with the optical fiber strands 1 at both ends of the 16-fiber optical fiber ribbon was 50 μm.

Comparative Example 1 H at 23 ° C. performed in Example 1
A 16-fiber optical fiber ribbon having a two-layer coating including an inner layer coating 16 and an outer layer coating 17 was manufactured without passing through the cooling cylinder 9 through which e gas flows. Has a thickness of 0.24 mm and a width of 3.2
It was 4 mm. Compared with Example 1, both the thickness and width of the optical fiber ribbon are small, and the coating thickness of the optical fiber element wires 1 at both ends of the optical fiber ribbon in the width direction of the optical fiber ribbon is 20 μm. Was thin. In addition, the resin of the coating 17 of the second layer was broken, that is, the state where the coating was not performed occurred, and the inclusion of air bubbles was observed in half of the entire length.

[Comparative Example 2] The forced cooling with He gas and the coating of the second layer of the tape material as in Example 1 were not performed,
Using a die having an elliptical opening (a width of the elliptical opening of 3.60 mm and a thickness of 0.28 mm), only one layer of coating is used.
When a 6-fiber optical fiber ribbon was manufactured, the average thickness of the manufactured optical fiber ribbon was 0.24 mm, the thickness of the partially raised portion was 0.30 mm, and the width was 3.2.
It was 0 to 3.45 mm. That is, the structure shown in FIG. 3 has a thickness of 0.24 mm and a width of 3.45 mm, and the structure shown in FIG. 4 has a maximum thickness of 0.30 m.
It was m and the width was 3.20 mm. In some cases, as shown in FIG. 5, one end has a coating of 30 μm on one end and the other has a coating of only 15 μm.

[0028]

As described above, according to the present invention, the coating of the optical fiber ribbon is made up of two layers, and moreover
Since the second-layer coating is formed after the coating of the first layer is forcibly cooled, it is possible to stably form a tape coating of several tens of μm outside the width direction of the optical fiber ribbon. It is possible to obtain a method for manufacturing a tape core wire.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a manufacturing apparatus for carrying out a method of manufacturing an optical fiber ribbon according to the present invention.

FIG. 2 is a cross-sectional view showing a state of an optical fiber tape core wire manufactured by the present invention.

FIG. 3 is a cross-sectional view showing a state of an optical fiber tape core wire manufactured according to Comparative Example 2 for showing the effect of the present invention.

FIG. 4 is a cross-sectional view showing a state of an optical fiber ribbon according to Comparative Example 2 as well.

FIG. 5 is a cross-sectional view showing a state of an optical fiber ribbon according to Comparative Example 2 as well.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical fiber strand, 6a, 6b ... Pressurizing type coating die (die), 9 ... Cylinder for forced cooling, 10 ... He gas cylinder, 1
6 ... First layer coating (cured UV curable resin), 17
... Second layer coating (cured UV curable resin).

Claims (2)

[Claims] 1. A step of arranging a plurality of optical fiber strands in a plane and applying an ultraviolet curable resin at once, and irradiating the ultraviolet curable resin coated on the optical fiber strands with ultraviolet rays. Curing the leveraged ultraviolet curable resin to produce an optical fiber tape core wire in which the optical fiber element wires are integrated into a tape shape; and by forcibly cooling the optical fiber tape core wire, curing The step of forcibly lowering the temperature of the ultraviolet curable resin, and the cooled optical fiber tape core wire are passed through the opening of the die filled with the fluidized ultraviolet curable resin to In the step of applying an ultraviolet curable resin to the outside of the wire, the gap between the optical fiber tape core wire and the opening is larger in the width direction of the optical fiber tape core wire than in the thickness direction. And the step of irradiating the ultraviolet curable resin applied to the optical fiber tape core with ultraviolet rays to cure the ultraviolet curable resin, and the thickness of the ultraviolet curable resin in the width direction is cured in the thickness direction. And a step of producing an optical fiber ribbon which is thicker than the thickness of the mold resin, and a method for producing an optical fiber ribbon. 2. The method for producing an optical fiber ribbon according to claim 1, wherein the forced cooling of the optical fiber ribbon is performed by using helium gas.