JPH10227955A - Coating device for ribbon of coated optical fibers and die used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the coating device which can manufacture a ribbon of coated optical fibers in an excellent coated optical fiber array state without thickness unevenness and the die used for the device. SOLUTION: The coating device for a ribbon of coated optical fibers has the die 12 having a nozzle 17, through which optical fibers 14 arrayed in plane in parallel to one another pass, formed at its center part, a partition member 13 which has a resin pool 27 supplied with coating resin 28, formed before the die 12 and also has a through hole 26 where the optical fibers 14 pass at the center part, and a die holder 11 which holds the die 12 and partition member 13 across a gap so that the nozzle 17 and through hole 26 are coaxial, and also has a tapered part 15 which decreases gradually in diameter in the passing direction of the optical fibers 14 on the nozzle 17 of the die 12. In this case, the taper angle of a tapered part 15 which is cut with one plane is set smaller than that of a tapered part 15 cut with a plane crossing the plane at right angles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber tape core for forming a tape-shaped multi-core optical fiber by applying a coating resin to a plurality of optical fibers arranged in parallel at predetermined intervals. The present invention relates to a wire coating apparatus and a die used for the same.

[0002]

2. Description of the Related Art A tape-shaped multi-core optical fiber ribbon in which a plurality of optical fibers are bundled along a plane in parallel with each other is composed of a plurality of optical fibers coated with a primary coating such as an ultraviolet curing resin or a silicon resin. It is formed by applying a thermoplastic resin such as an ultraviolet curable resin or nylon as a secondary coating for reinforcement in a state where the fiber strands are arranged in parallel with each other at predetermined intervals.

When forming such a tape-shaped multi-core optical fiber core, a secondary coating having a uniform film thickness is formed stably, and the arrangement of the optical fibers is not disturbed. For this purpose, as a coating apparatus for an optical fiber tape, there are known techniques disclosed in Japanese Patent Application Laid-Open Nos. 6-174987, 7-46882 and 209565. ing.

Among them, the one disclosed in Japanese Patent Application Laid-Open No. Hei 6-174879 discloses a secondary coating with a coating die (hereinafter simply referred to as a die) containing a resin passing through an optical fiber. A drag flow of the material is generated, and the drag flow generates a self-centering force of the optical fiber strand with respect to the die, that is, a self-centering force that automatically displaces the optical fiber strand so that the optical fiber strand is stabilized at the center of the die. A secondary coating having a large thickness can be stably formed. For this reason, the taper angle of the protruding portion of the optical fiber strand cut on the plane where the optical fiber strands are arranged is set to 1/2 to 1 of the taper angle of the protruding section of the optical fiber strand cut on a plane perpendicular to the plane. It is said that setting to / 4 is advantageous.

[0005] Japanese Utility Model Publication No. 7-46882 discloses that at least two sets of resin supply ports are provided at point-symmetric positions on the side wall of a die, and the pressure of the coating resin supplied to these resin supply ports is independently controlled. By performing the adjustment, a tape-shaped multi-core optical fiber core wire with less deviation is obtained.

Further, in Japanese Unexamined Patent Application Publication No. 7-209565, a resin outlet is provided on a die which faces the upper and lower surfaces and both side surfaces of a tape-shaped multi-core optical fiber core. By appropriately setting the resin supply ratio from the resin outlet, it is possible to secure a sufficient side wall thickness of the secondary coating without disturbing the arrangement of the optical fibers.

[0007]

Problems to be Solved by the Invention Japanese Patent Laid-Open No. 6-17498
No. 7, JP-A-7-46882, or JP-A-Heisei 209565 discloses a conventional coating apparatus for optical fiber ribbons.
In the device disclosed in Japanese Patent Publication No. 174897, as the number of optical fiber strands increases, the taper angle of the protruding portion cut by the plane in which these optical fiber strands are arranged is reduced, and the running angle is reduced by a plane perpendicular to the plane. It is necessary to increase the taper angle of the cut-off running section. As a result, the self-centering force in the direction orthogonal to the plane in which the optical fiber strands are arranged weakens, and as a result, the optical fiber strand deviates from the plane in which the optical fiber strands are arranged, and the arrangement state of the optical fiber strands May be disturbed.

Further, Japanese Unexamined Patent Publication No. Hei 7-46882 and Japanese Unexamined Patent Publication No. Hei 7-209565 disclose a method of simply adjusting a resin pressure and a supply amount thereof which are not involved in a self-centering force of an optical fiber to a die. Only the thickness of the secondary coating of the tape-shaped multi-core optical fiber is controlled. As a result, there is a disadvantage that the arrangement of the optical fibers is easily disturbed due to a change in coating conditions or the like.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coating apparatus for an optical fiber ribbon capable of producing a tape-shaped multi-core optical fiber having a good arrangement of optical fibers and having no uneven thickness, and a die used therefor. Is to provide.

[0010]

An important factor in manufacturing a tape-shaped multi-core optical fiber is to arrange the optical fibers in the same plane without any disturbance. From such a viewpoint, the present inventors consider self-centering force as a factor for improving the arrangement of optical fiber strands,
Dies with variously changed nozzle taper angles were manufactured, and coating experiments were performed on optical fibers. Further, in consideration of the shape of the tape-shaped multi-core optical fiber, the taper angle θ of the die nozzle cut at a plane where a plurality of optical fibers are arranged.
₁ and the taper angle θ of the nozzle cut by a plane perpendicular to this
Also noticed _two .

As a result, when the taper angle θ ₁ of the nozzle of the die cut at the plane where the optical fiber strands are arranged is small, and the taper angle θ _{2 of the} nozzle cut at the plane orthogonal to the plane is large, The arrangement of the lines was found to be abnormally disturbed. The reason for this is that the self-centering force in the direction along the plane where the optical fiber strands are arranged is large, and the self-centering force in the direction perpendicular to this plane is small. The balance trying to keep on the same plane is broken,
In any case, it is considered that a balance state is created in which the optical fiber is repelled in a direction orthogonal to the plane on which the optical fiber is arranged, and the arrangement of the optical fiber is disturbed. Further, when the optical fiber is large taper angle theta ₁ of the nozzle of the die taken along a plane arranged, and has a small taper angle theta ₂ of the nozzle taken along a plane perpendicular to this plane, i.e. theta _1> theta _In the case of ₂ , it was found that the arrangement of the optical fiber was good. Where θ ₂ = 0
Then, the arrangement of the optical fibers was disturbed. This is probably because the self-centering force in the direction orthogonal to the plane where the optical fiber strands are arranged almost disappears, and the optical fiber strands cannot be held in the same plane.

From the above experimental results, 1> θ ₂ / θ ₁
It has been found that when a nozzle having a taper angle satisfying > 0 is used, a good tape-shaped multi-core optical fiber core in which optical fiber strands are arranged on the same plane without disturbance is obtained.

In a first embodiment of the present invention, there is provided a die having a nozzle formed at a central portion through which a plurality of optical fibers arranged parallel to each other along one plane pass, and a coating resin is provided between the die. A partition member having a central portion formed with a through hole through which the optical fiber passes while forming a resin reservoir to be supplied, and a gap between the die and the partition member such that the nozzle and the through hole are coaxial. And a die holder for holding the optical fiber tape with the taper portion having a tapered portion whose diameter gradually decreases along the passing direction of the optical fiber, formed on the nozzle of the die. The tapered angle of the cut tapered portion is set to be larger than the taper angle of the tapered portion cut by a plane orthogonal to the one plane.

According to the present invention, the taper angle of the tapered portion cut at the plane where the plurality of optical fibers are arranged is larger than the taper angle of the tapered portion cut at the plane orthogonal to the plane where the plurality of optical fibers are arranged. Because of the large setting, the self-centering force in the direction perpendicular to the plane in which the plurality of optical fibers are arranged becomes larger than the self-centering force in the direction along the plane in which the plurality of optical fibers are arranged. The deviation of the optical fiber from the plane where the optical fibers are arranged is suppressed.

A second embodiment of the present invention is used in a coating apparatus for an optical fiber ribbon for applying a coating resin to a plurality of optical fibers arranged in parallel along one plane in parallel with each other. A nozzle through which the coating resin is supplied and through which the plurality of optical fibers pass is provided at a central portion, and a tapered portion whose diameter gradually decreases along the passing direction of the plurality of optical fibers is formed in the nozzle. A die, wherein the taper angle of the tapered portion cut by the one plane is set to be larger than the taper angle of the tapered portion cut by a plane orthogonal to the one plane.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a coating apparatus for an optical fiber ribbon according to a first embodiment of the present invention, the cross-sectional shape of a tapered portion cut in a plane perpendicular to the optical fiber passing direction is parallel to one plane. It may have a pair of straight wall portions and a pair of curved wall portions facing each other across the pair of straight wall portions.

In this case, the cross-sectional shape of the tapered portion cut by a plane perpendicular to the optical fiber passing direction is an elongated hole shape along the optical fiber arrangement direction, and extends over the entire circumference of the tapered portion. The resin flow is smooth.

Further, in the die according to the second aspect of the present invention, the cross-sectional shape of the tapered portion cut in a plane perpendicular to the optical fiber passing direction includes a pair of straight wall portions parallel to one plane, It may have a pair of curved wall portions facing each other across a pair of straight wall portions.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the coating apparatus for an optical fiber ribbon according to the present invention incorporating the die according to the present invention will be described.
This will be described in detail with reference to FIGS.

FIG. 1 showing a sectional structure of this embodiment and FIG.
FIG. 2 showing a cross-sectional structure taken along the line II-II, FIG. 3 showing a state in which a resin is applied to the optical fiber corresponding to FIG. 1, and FIGS. As shown in FIG. 5 showing a cross-sectional shape taken along the arrow VV in the middle, a die 12 and a partition member 13 are accommodated in a cylindrical die holder 11 so as to be vertically separated from each other.

In the center of the die 12 attached to the lower side of the die holder 11, the cross-sectional area in a plane orthogonal to the direction of transport of the optical fiber 14 from the upper side to the lower side in FIG. , A nozzle 17 having a tapered portion 15 gradually decreasing toward the lower side and a straight portion 16 having a constant cross-sectional area along the transport direction of the optical fiber 14 are formed. The cross-sectional shape of the straight portion 16 in a plane orthogonal to the transport direction of the optical fiber strand 14 is similar to the cross-sectional shape of the tape-shaped multi-core (four in the illustrated example) optical fiber core 18 pulled out from the nozzle 17. A pair of straight wall portions 19 and a pair of semi-elliptical curved wall portions 20 facing each other with the pair of straight wall portions 19 interposed therebetween.
And The cross-sectional shape of the tapered portion 15 includes a straight wall portion 21 similar to the straight portion 16 and a curved wall portion 22 having a semi-elliptical shape.
The higher the position above the connection portion with No. 6, the more the above-mentioned similar shape is deviated. That is, the taper angle θ ₁ of the tapered portion 15 cut by a plane on which the plurality of optical fiber strands 14 are arranged, that is, a plane including the axes of all the optical fiber strands 14 arranged ideally, is It is set so as to be larger than the taper angle θ ₂ of the tapered portion 15 cut by an orthogonal plane, in other words, 1> (θ ₂ / θ ₁ )> 0.

In this embodiment, the length of the straight wall portion 21 (FIG. 1)
(Length in the middle, left and right directions) is set to a constant size along the passing direction of the optical fiber 14, while the semi-ellipse of the curved wall portion 22 is reduced toward the straight portion 16. It is set to become. However, this straight wall portion 21
May be set to be shorter as the straight portion 16 is closer. Further, in the present embodiment, the curved wall portions 20 and 22 are formed in a semi-elliptical shape. However, a curved portion which is not discontinuous at a connection portion with the straight wall portions 19 and 21 is formed so as not to obstruct the flow of the resin. Any other shape that is possessed can be employed.

At the center of the partition member 13 attached to the upper side of the die holder 11, the cross-sectional area in a plane orthogonal to the direction of transport of the optical fiber wires 14 from the upper side to the lower side in FIG. A straight portion 23 which is constant along the transport direction of the strand 14, a tapered portion 24 whose cross-sectional area gradually decreases downward in FIG. 1, and a cross-section along the transport direction of the optical fiber 14 A through hole 26 having a constant straight portion 25 is formed. The cross-sectional shape of the through-hole 26 in a plane orthogonal to the transport direction of the optical fiber strand 14 is a tape-shaped multi-core (four in the illustrated example) drawn from the nozzle 17.
8 is similar to the cross-sectional shape of FIG.
The lower straight portion 25 is set smaller than the lower straight portion 25. However, it goes without saying that a sufficient gap is formed between the lower straight portion 23 and the optical fiber 14.

A resin reservoir 27 communicating with the nozzle 17 of the die 12 is formed between the die 12 and the partition member 13. The resin reservoir 27 has a predetermined pressure from a coating resin supply source (not shown). Is supplied.

Generally, it is known that a self-centering force acting on a striatum passing through a tapered hole filled with liquid acts toward the center of the tapered hole. Similarly, since the optical fiber strand 14 as a linear body runs also in the tapered portion 15 of the nozzle 17 of the die 12, a resin flow is formed as shown by arrows in FIGS. Centering force works. This allows
The optical fiber 14 is automatically centered with respect to the tapered portion 15 and is stabilized in a state where the optical fibers 14 are arranged in parallel on the same plane. Also, the self-centering force is weakened As the taper angle theta _1, theta ₂ is increased, the taper angle theta ₁ Conversely, theta ₂ is increased As the smaller.

Therefore, the plurality of optical fiber wires 14 arranged parallel to each other along the same plane are
The resin enters the nozzle 17 of the die 12 from the through hole 26 through the resin reservoir 27, and while passing therethrough, the coating resin 28 having a predetermined thickness is applied to an external ultraviolet irradiation device (not shown). The fed and cured 4-core optical fiber ribbon 18 is obtained.

In the above-described embodiment, the tape-shaped four-core optical fiber core 18 has been described, but as shown in FIG.
Such a tape-shaped four-core optical fiber core 18 is continuously formed on the same pass line by a resin connecting material 29 and cured by curing the resin connecting material 29. The same effect can be obtained by using the die according to the present invention in the production of 30 or more tape-shaped multi-core optical fibers.

The tapered portion 15 and the straight portion 1
When the cross-sectional shape of each of the nozzles 6 is rectangular, that is, the curved wall portion is also formed of a straight wall portion, as shown in FIG. 7 showing the cross-sectional structure of the nozzle 17 corresponding to FIG.
At the corners of the nozzles 17 where the nozzles 31 abut each other, an area Z where the resin flow velocity is low depends on the shape of the nozzles 17, and the resin flow is hindered, exerting an adverse effect on the self-centering force on the optical fiber 14, and causing both ends in the arrangement direction. , The arrangement position of the optical fiber wires 14 located at the position tends to be slightly disturbed.

In this respect, in this embodiment, since the cross-sectional shape of the nozzle 17 is a long hole, a discontinuous corner portion is not formed as in the case of making the nozzle 17 into a rectangular shape, and the resin flows smoothly. As a result, the self-centering force on the optical fiber 14 works effectively, and a good tape-shaped optical fiber core 18 having no arrangement disorder can be obtained.

Next, four optical fiber cores 32a having a diameter of 250 μm and a secondary coating layer formed on an optical fiber strand 14 having a diameter of 125 μm using the above-described coating apparatus for an optical fiber ribbon. To 32d, and a coating resin 28 is applied thereto all at once to form a tape-shaped four-core optical fiber core wire 33.
Was manufactured. Then, in order to confirm the effect of the present invention, as a method for quantitatively evaluating the arrangement disorder of the optical fiber cores 32a to 32d, as shown in FIG. 8, the optical fiber cores 32a, 32a, to the plane (straight line) L passing through the center of the 32d, the deviation amount of the two optical fibers 32b located in the middle, 32c axial position of Δ _b, Δ _c
Was used as an evaluation parameter.

(Experimental Example 1) θ ₁ = 10 °, θ ₂ = 6 °
A die having a nozzle having a sectional shape as shown in FIG. 7 was used. In this _{case, Δ b = 12μm, Δ c} = became a 10 [mu] m, the optical fiber 32a which is substantially located on both sides in the arrangement direction as shown in FIG. 7, 32d of the other optical fiber 32b, There was a tendency to shift with respect to a plane passing through the axis of 32c.

(Experimental Example 2) In order to generate a self-centering force larger than that of Experimental Example 1, θ ₁ = 5 °,
A die having a nozzle at θ ₂ = 3 ° and a cross-sectional shape as shown in FIG. 7 was used. In this case, the amount of deviation delta _b = 9 .mu.m, delta
_c = 8 μm, and the optical fiber cores 32a and 32d located on both sides in the arrangement direction substantially become the other optical fiber cores 32b and 3 as shown in FIG.
There was a tendency to shift with respect to a plane passing through the axis of 2c.

(Experimental Example 3) θ ₁ = 10 °, θ ₂ = 6 °
A die having a nozzle having a sectional shape as shown in FIG. 5 was used. In this _{case, Δ b = 6μm, Δ c} = 5μm , and the
As in Experimental Examples 1 and 2 due to the inhibition of resin flow, the optical fibers 32a and 32d located on both sides in the arrangement direction are displaced from the plane passing through the axes of the other optical fibers 32b and 32c. No trends occurred.

(Experimental Example 4) In order to generate a self-centering force larger than that of Experimental Example 1, θ ₁ = 5 °,
At θ ₂ = 3 °, a die having a nozzle having a sectional shape as shown in FIG. 5 was used. In this case, the amount of deviation delta _b = 3 [mu] m, delta
_c = 3 μm, and the optical fiber cores 32a and 32d located on both sides in the arrangement direction are different from the optical fiber cores as in Experimental Examples 1 and 2 caused by the inhibition of resin flow, as in Experimental Example 3. There was no tendency to shift with respect to a plane passing through the axes of 32b and 32c.

Comparative Example 1 θ ₁ = 80 °, θ ₂ = 60 °
A die having a nozzle having a sectional shape as shown in FIG. 5 was used. In this case, since the self-centering force becomes smaller, which in accordance with the amount of deviation is Δ _b = 21μm, Δ
_c = 18 μm.

(Comparative Example 2) θ ₁ = 6 °, θ ₂ = 10 °
A die having a nozzle having a sectional shape as shown in FIG. 7 was used. In this case, the amount of deviation _{Δ b = 35μm, Δ c =} 38
μm, which is very large.
The 2d arrangement was disordered randomly.

[0037]

According to the present invention, the taper angle of the tapered portion cut by a plane where a plurality of optical fibers are arranged is reduced by the taper angle of the tapered portion cut by a plane orthogonal to the plane where a plurality of optical fibers are arranged. The self-centering force in the direction perpendicular to the plane in which the plurality of optical fibers are arranged becomes larger than the self-centering force in the direction along the plane in which the plurality of optical fibers are arranged. The deviation of the optical fiber from the plane where the optical fibers are arranged is suppressed. As a result, the arrangement state of the optical fibers can be favorably maintained.

Further, the cross-sectional shape of the tapered portion cut in a plane perpendicular to the optical fiber passing direction is such that a pair of straight wall portions parallel to one plane and a pair of opposed wall members sandwiching the pair of straight wall portions. In the case of having a curved wall portion, the cross-sectional shape of the tapered portion cut by a plane perpendicular to the optical fiber passing direction becomes a long hole shape along the arrangement direction of the optical fiber, and is formed over the entire circumference of the tapered portion. Because the resin flows smoothly over
Does not adversely affect the occurrence of self-centering force,
The arrangement state of the optical fibers can be better maintained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a schematic structure of an embodiment of a coating device for an optical fiber ribbon according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a cross-sectional view showing a state during a coating operation by the optical fiber ribbon coating apparatus shown in FIG. 1;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

5 is a sectional view taken along the line VV in FIG. 3;

FIG. 6 is a cross-sectional view illustrating a structure of a tape-shaped eight-core optical fiber cable which is an object of the present invention.

FIG. 7 is a cross-sectional view corresponding to FIG. 5, illustrating a structure of a die according to another embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a structure of a tape-shaped four-core optical fiber cable which is an object of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Die holder 12 Die 13 Partition member 14 Optical fiber 15 Taper part 16 Straight part 17 Nozzle 18 Tape-shaped four-core optical fiber core 19 Straight wall 20 Curved wall 21 Straight wall 22 Curved wall 23 Straight part 24 Taper Part 25 Straight part 26 Through-hole 27 Resin pool part 28 Coating resin 29 Resin connecting material 30 Tape-shaped eight-core optical fiber core 31 Linear wall part 32a to 32d Optical fiber core 33 33 Tape-shaped four core optical fiber L Arrangement direction a plane passing through the center of the optical fiber positioned at both ends (linear) delta _b, the amount of deviation of the axis position of the delta _c optical fiber

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihisa Sato 1 Tagamachi, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Ken Takahashi 1-Tagamachi, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo (72) Inventor Ryohide Oka 1-chome, Taya-cho, Sakae-ku, Yokohama, Kanagawa Prefecture Sumitomo Electric Co., Ltd.

Claims (4)

[Claims] 1. A die having a nozzle formed at a central portion through which a plurality of optical fibers arranged in parallel with each other and passing along a plane, and a resin reservoir for supplying a coating resin is formed between the die. A partition member having a through hole through which the optical fiber passes and formed at the center, and a die holder for holding the die and the partition member with a gap therebetween so that the nozzle and the through hole are coaxial. An optical fiber coating apparatus comprising: a nozzle having a tapered portion having a diameter gradually decreasing along a passing direction of the optical fiber, wherein the tapered angle of the tapered portion cut by the one plane is set to the one. A coating device for an optical fiber ribbon, wherein the taper portion is set to be larger than a taper angle of the tapered portion cut by a plane perpendicular to the plane. 2. A cross-sectional shape of the tapered portion cut by a plane perpendicular to a direction in which the optical fiber passes through a pair of straight wall portions parallel to the one plane and a pair of straight wall portions sandwiching the pair of straight wall portions. The coating apparatus for an optical fiber ribbon according to claim 1, comprising a pair of curved wall portions facing each other. 3. A coating apparatus for an optical fiber ribbon for collectively applying a coating resin to a plurality of optical fibers arrayed along one plane parallel to each other, wherein the coating resin is supplied. A die having a nozzle through which a plurality of the optical fibers pass is provided at a central portion, and a taper portion having a diameter gradually reduced along the passing direction of the plurality of the optical fibers is formed in the nozzle. A die, wherein a taper angle of the cut tapered portion is set to be larger than a taper angle of the tapered portion cut by a plane orthogonal to the one plane. 4. A cross-sectional shape of the tapered portion cut along a plane perpendicular to a direction in which the optical fiber passes, a pair of straight wall portions parallel to the one plane and a pair of the straight wall portions interposed therebetween. The die according to claim 3, comprising a pair of curved wall portions facing each other.