Glass manufacturing – Processes of manufacturing fibers – filaments – or preforms – Process of manufacturing optical fibers – waveguides – or...
Reexamination Certificate
1997-12-04
2003-09-02
Hoffmann, John (Department: 1731)
Glass manufacturing
Processes of manufacturing fibers, filaments, or preforms
Process of manufacturing optical fibers, waveguides, or...
C065S432000
Reexamination Certificate
active
06612134
ABSTRACT:
FIELD OF THE INVENTION
In a method of making an optical fiber product, the present invention relates to a technique in which a control step is provided between the time at which a drawing step is completed and the time at which its subsequent processing step is started, and the operating time of the control step is optimally regulated in relation to the ambient temperature during this step.
BACKGROUND OF THE INVENTION
The conventional method of making an optical fiber product includes, at least, a preform manufacturing step of making a preform for optical fiber by means of a so-called VAD (vapor phase axial deposition) technique or the like, a drawing step of drawing thus obtained preform so as to yield a coated optical fiber, and a processing step of making a ribbon-type optical fiber or an optical fiber code by utilizing thus obtained coated optical fiber, whereby a desired optical fiber product has been made in consequence of all these steps. In this specification, the coated optical fiber refers to a light guide member which is obtained by the above-mentioned drawing step and comprises, as shown in
FIG. 2
, a glass fiber
3
constituted by a core having a predetermined refractive index and a cladding which is disposed around the outer periphery of the core and has a refractive index lower than that of the core, and a primary coating layer
40
made of a UV-curing resin or the like disposed around the outer periphery of the glass fiber
3
. As the prior art relating to the above-mentioned preform manufacturing step, for example, U.S. Pat. No. 4,367,085 discloses the VAD technique. The prior art relating to the above-mentioned drawing step is disclosed in U.S. Pat. No. 4,123,242, for example. As the prior art relating to the above-mentioned processing step, U.S. Pat. No. 5,561,730 discloses a configuration of a ribbon-type optical fiber.
In the above-mentioned method of making an optical fiber product, after the coated optical fiber is wound around a reel
1
(first winding member) once (after the completion of the drawing step), the subsequent processing step is performed while the coated optical fiber is directly rewound around another bobbin or after the coated optical fiber is further temporarily rewound around a bobbin (second winding member) which is different from the above-mentioned reel.
For example, in the drawing apparatus shown in
FIG. 1
, the glass fiber
3
(see
FIG. 2
) constituted by the core and the cladding is obtained when a tip portion of an optical fiber preform
10
softened by a heating oven
11
is drawn into the direction of depicted arrow S
1
, while a predetermined tension is applied thereto, and is wound around the reel
1
rotating in the direction indicated by depicted arrow S
2
. At this time, a coating apparatus
12
applies a resin to the outer periphery of the glass fiber
3
, and the primary coating layer
40
made of the UV-curing resin, which is cured in a curing furnace
13
, is subsequently formed. Accordingly, in this drawing step, a coated optical fiber
4
, in which the primary coating layer
40
is formed on the outer periphery of the glass fiber
3
, is wound around the reel
1
.
The processing step performed after the above-mentioned drawing step includes, for example, a step of making a ribbon-type optical fiber
6
shown in FIG.
3
. In this step, first, the coated optical fiber
4
wound around the reel
1
in consequence of the drawing step is divisionally wound around a plurality of bobbins simultaneously. Thereafter, a plurality of coated optical fibers
4
respectively wound around the bobbins are collectively covered with a coating layer
60
made of a UV-curing acrylate resin or the like in the state where they are arranged horizontally, whereby the ribbon-type optical fiber
6
shown in
FIG. 3
is obtained.
Also, the above-mentioned processing step includes a step of yielding a colored coated optical fiber
5
in which, as shown in
FIG. 4
, a coloring layer
50
made of a UV-curing acrylate resin containing a pigment or the like is formed on the outer periphery of the optical fiber bundle
4
wound around the reel
1
. This colored coated optical fiber
5
can also be employed in the ribbon-type optical fiber
6
shown in FIG.
3
. Specifically, the colored coated optical fibers
5
are collectively covered with the coating layer
60
made of a UV-curing acrylate resin or the like in the state where they are arranged horizontally, whereby the ribbon-type optical fiber
6
shown in
FIG. 5
is obtained.
Further, the above-mentioned processing step
15
includes a step of yielding a single-filament optical fiber code
7
in which, as shown in
FIG. 6
, a coating layer
70
made of nylon or the like is disposed around the outer periphery of the coated optical fiber
4
, while the coated optical fiber
4
is being rewound from the reel
1
.
In addition, the above-mentioned processing step includes a step of rewinding the coated optical fiber
4
, which has been wound around the reel
1
in the above-mentioned drawing step, simply around a single bobbin different from the reel
1
or divisionally around a plurality of bobbins.
SUMMARY OF INVENTION
In the conventional method of making an optical fiber product, no control has been made at all with respect to the time for starting the processing step (including the step of rewinding the coated optical fiber
4
around the second winding member) that is effected for forming the coloring layer
50
, the casing
60
, or the casing
70
and the like after the completion of the drawing step (including the step of winding the coated optical fiber
4
around the first winding member).
In the optical fiber product (the ribbon-type optical fiber
6
, single-filament optical fiber code
7
, colored coated optical fiber
5
, coated optical fiber
4
rewound around another bobbin from the reel
1
, or the like) thus made by the conventional manufacturing method, there have been cases where delamination (
8
indicating a delaminated portion in
FIG. 7
) locally occurs between the glass fiber
3
and the primary coating layer
40
disposed around the outer periphery thereof, thereby increasing transmission loss. Also, this delamination has been causing the strength to deteriorate.
Similarly, in the ribbon-type optical fiber
6
(see
FIG. 5
) obtained when a plurality of colored coated optical fibers
5
each having the coloring layer
50
made of a UV-curing resin containing a coloring pigment formed around the outer periphery of the coated optical fiber
4
are collectively covered with the coating layer
60
made of a UV-curing resin while being arranged horizontally, there have been cases, as shown in
FIG. 8
, where color delamination (
9
indicating a color-delaminated portion in
FIG. 8
) occurs when the coating layer
60
is removed therefrom.
The locally generated delamination has mainly been studied from the viewpoint of improving the composition of the primary coating layer so as to increase its bonding force, whereas the color delamination has been studied from the viewpoint of improving the coloring layer. In either case, however, the above-mentioned problem has not been solved.
Hence, it is an object of the present invention to provide a method of making an optical fiber product, which efficiently restrains the primary coating layer or ink (coloring layer) of the resulting optical fiber product from delaminating.
Specifically, the method of making an optical fiber product according to the present invention comprises, at least, a drawing step (first step) of winding around a first winding member (e.g., reel) a coated optical fiber in which a primary coating layer made of a UV-curing resin or the like is formed around the outer periphery of a glass fiber having a core and a cladding; a processing step (second step) of rewinding around a second winding member (bobbin), which is different from the first winding member, the coated optical fiber wound around the first winding member; and a control step (third step), provided between the drawing step and the processing step, of h
Aikawa Haruhiko
Hasegawa Takashi
Shimoda Koji
Yoshida Motohide
Hoffmann John
Sumitomo Electric Industries Ltd.
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