Plastic and nonmetallic article shaping or treating: processes – Optical article shaping or treating – Optical fiber – waveguide – or preform
Reexamination Certificate
1999-06-24
2001-10-30
Vargot, Mathieu D. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Optical article shaping or treating
Optical fiber, waveguide, or preform
C118S405000, C118S420000, C264S001280, C264S001380, C425S114000, C425S174400, C425S463000, C427S163200
Reexamination Certificate
active
06309567
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to manufacturing a plurality of optical fiber ribbons formed by applying coating resin in a lump to coated optical fibers arranged in parallel on one and the same plane, and a separable optical fiber ribbon formed by further integrally applying coating resin to the optical fiber ribbons arranged in parallel on one and the same plane. Particularly, the present invention relates to a collectively coating die device for manufacturing an optical fiber ribbon and a separable optical fiber ribbon, a manufacturing device having such a collectively coating die device for manufacturing a separable optical fiber ribbon, and a method of manufacturing such a separable optical fiber ribbon.
2. Description of the Conventional
Conventionally, to manufacture a separable optical fiber ribbon shown in
FIG. 5A
by way of example, constituted by a plurality of coated optical fibers are coated integrally, a die device having a branch portion
30
a
shown in
FIG. 8
is known, as disclosed in Unexamined Japanese Patent Publication (kokai) No. Hei. 3-150519.
However, there is a problem in a method of manufacturing a separable optical fiber ribbon with such a die device having a branch portion as disclosed in the above-mentioned publication. That is, when the line speed increases, the arrangement of coated optical fibers
1
in a separable optical fiber ribbon
26
may fall into disorder as shown in
FIG. 5C
, and in some cases, there occur so-called fault of fiber planarity in the coated optical fibers
1
due to the displacement of the coated optical fibers
1
from the positions on one and the same plane on a large scale.
With such fault of fiber planarity, it becomes impossible to mount the coated optical fibers
1
of the separable optical fiber ribbon
26
onto V-grooves of a V-grooved board properly in an cable installation step or the like, so that it is difficult to connect the coated optical fibers
1
by fusion splice. Further, there is a fear that the fault of fiber planarity causes increase of transmission loss. It is therefore extremely important to suppress such fault.
Specifically, as shown in
FIG. 6
, the displacement &Dgr;a-&Dgr;f of the center of each of the coated optical fibers
1
disposed in the separable optical fiber ribbon
26
relative to the straight line L connecting the respective centers of the coated optical fibers
1
disposed in both ends of the separable optical fiber ribbon
26
is referred to as a fiber planarity. It is necessary to make the respective fiber planaritys as small as possible.
Particularly, recently, the production technique has been improved so that the line speed is increased conspicuously. Therefore, the problem that fault of fiber planarity is increased has become manifest.
The present inventor investigated the cause of this problem and found out the following fact. In a step of manufacturing optical fiber ribbons, in a collective resin coating method using such a collectively coating die device having a branch portion
30
a
as shown in
FIG. 8
by way of example, unstable vortex flows J of coating resin appear in the branch portion
30
a
in the direction reverse to the moving direction of the coated optical fibers
1
so as to disturb self-centering force generated in the coating resin in the collectively coating die device. Consequently, the fault of fiber planarity is increased.
Generally, when a linear body is passed through a die having a tapered portion and storing a liquid, a drag flow is generated in the liquid with the passage of the linear body. This drag flow makes a force to act on the linear body to dispose the linear body at the center of the die, that is, self-centering force.
Therefore, generally, when optical fibers pass through optical fiber passageways, respectively, of the collectively coating die device
2
filled with liquid-type coating resin, such self-centering force acts on the optical fibers so that the optical fibers are disposed at the center of an outlet opening
35
.
The present inventor has found out the following fact. When the conventional collectively coating die device shown in
FIG. 8
is used, a resin flow moving in the moving direction of the optical fibers collides with the branch portion
30
a
to generate unstable vortex flows J when the line speed of the optical fibers increases, and these vortex flows J disturb the self-centering force to cause the fault of fiber planarity. The present inventor has given light onto a structure of a die device which can eliminate such vortex flows to thereby achieve the present invention.
SUMMARY OF THE INVENTION
It is an object of the present invention to manufacture a separable optical fiber ribbon in which coated optical fibers are arranged on a plane with high accuracy.
The present invention provides a collectively coating die device for applying coating resin in a lump to coated optical fibers arranged in parallel on one and the same plane so as to form a plurality of optical fiber ribbons at the same time. In the coating die devices, the collectively coating die device comprises a nipple portion and a die portion, a resin accumulation space formed between the nipple portion and the die portion, each of the nipple portion and the die portion having two parallel planes and having a plurality of optical fiber passageways shaped like ellipse in section and provided in the direction perpendicular to the planes, each of the plural optical fiber passageways of the nipple portion having a tapered portion, each of the plural optical fiber passageways of the die portion being constituted by a tapered portion and a straight portion in order from an inlet opening side, the optical fiber passageways of the die portion being disposed so as to correspond to the optical fiber passageways of the nipple portion respectively through the resin accumulation space.
Further, the present invention provides an apparatus and a method for manufacturing an optical fiber ribbon and a separable optical fiber ribbon, which uses such a collectively coating die device.
According to a collectively coating die device of the present invention, also in the case of applying resin to coated optical fibers at a high line speed, it is possible to reduce fiber planaritys of optical fibers in the optical fiber ribbons conspicuously. As a result, the coated optical fibers could be mounted on V-grooves of a V-grooved board accurately without any problem at the time of connection of the coated optical fibers of the separable optical fiber ribbon by fusion splice. Further, it is possible to avoid increase of transmission loss caused by fault of fiber planarity.
Further, the productivity of a separable optical fiber ribbon can be improved by using a collectively coating die device according to the present invention, so that it is possible to obtain an effect to reduce the manufacturing cost.
REFERENCES:
patent: 5127361 (1992-07-01), Matsuda et al.
patent: 5486378 (1996-01-01), Oestreich et al.
patent: 5904883 (1999-05-01), Hattori et al.
patent: 5976611 (1999-11-01), Okuno et al.
patent: 6030658 (2000-02-01), Tsuchiya et al.
patent: 0 841 582 (1998-05-01), None
patent: 2-180733 (1990-07-01), None
patent: 3-150510 (1991-06-01), None
patent: 3-150519 (1991-06-01), None
Hattori Tomoyuki
Kobayashi Kohei
Okuno Kaoru
Takahashi Ken
Tsuchiya Ichiro
McDermott & Will & Emery
Sumitomo Electric Industries Ltd.
Vargot Mathieu D.
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