TECHNICAL FIELD
The present invention relates to an optical fiber
ribbon of an intermittently fixed type in which adjacent
optical fiber cores are intermittently fixed, and an
optical fiber cable.
BACKGROUND ART
In recent years, in an optical fiber cable, the
desires of a higher density and a thinner diameter have
been increased. In order to attain the ultimate thin
diameter, it is more advantageous to gather optical fiber
cores each having a single core together than a structure
of the optical fiber ribbon. However, in a case that the
optical fiber cores each having the single core are
gathered together, there is a problem that a connecting
workability may be deteriorated, for example, such that a
batch fusion splicing is impossible.
In order to solve this problem, in the optical fiber
ribbon having two or more optical fiber cores arranged in
parallel to each other, the optical fiber ribbon of an
intermittently fixed type in which a plurality of coupling
portions coupling only the optical fiber cores adjacent to
each other are arranged two-dimensionally and
intermittently in a longitudinal direction and a width
direction of the optical fiber cores has been proposed (for
example, refer to patent documents 1 to 5).
In addition, by the expansion of recent FTTH (Fiber
To The Home), the optical fiber ribbon often has been
separated into single cores to connect to each of the
optical fiber cores each having single core.
When this connecting work is carried out, an outer
diameter of the coating of the optical fiber core becomes
larger than a hole diameter of a mechanical splice or a
field assembled connector if a tape forming member is left
on the outer circumference of the optical fiber core having
the single core, and thus, things may occur where the
optical fiber core may not be inserted into those hole
portions. Hence, after separating the optical fiber ribbon
into the single core, processing for removing the tape
forming member on the surface of the optical fiber core is
required.
[PRIOR ART DOCUMENT]
[PATENT DOCUMENT]
[Patent Document 1] JP 2007-279226A
[Patent Document 2] JP 2003-241041A
[Patent Document 3] JP 4143651B
2
[Patent Document 4] JP H06-181009A
[Patent Document 5] JP 2003-232972A
DISCLOSURE OF INVENTION
However, in the optical fiber ribbon united by the
coupling portions of the tape forming member, in which the
adjacent optical fiber cores are arranged in parallel
spaced from each other and the tape forming member covers
the outer circumference of each optical fiber cores, since
the entire circumference of the optical fiber core is
covered with the tape forming member after the single core
separation, it is difficult to remove the tape forming
member even if the adhesion of a colored layer of the
optical fiber core and the tape forming member is made
lower.
Also, even if a special removing tool is used,
removing solely between the tape forming member and the
colored layer is possible, but, since the entire
circumference of the optical fiber core is covered with the
tape forming member, it is difficult to remove the tape
forming member.
In view of the foregoing problems, an object of the
present invention is to provide an optical fiber ribbon and
an optical fiber cable capable of easily removing a tape
forming member after single core separation.
An aspect of the present invention provides an
optical fiber ribbon including a plurality of optical fiber
cores arranged in parallel spaced from each other; and a
tape forming member having a coating portion covering an
outer circumference of the optical fiber cores, and a
coupling portion, integrally formed with the coating
portion, intermittently coupling adjacent optical fiber
cores, wherein the coating portion has an opening portion
to expose a part of surfaces of the optical fiber cores,
and at least a part of the coating portion is continuous in
a longitudinal direction of the optical fiber cores.
Another aspect of the present invention provides an
optical fiber cable implementing the foregoing optical
fiber ribbon.
According to the present invention, it is possible to
provide the optical fiber ribbon and the optical fiber
cable capable of easily removing the tape forming member
after the single core separation.
BRIEF DESCRIPTION OF DRAWINGS
3
FIG. 1 is a top view illustrating an example of an
optical fiber ribbon according to an embodiment of the
present invention;
FIG. 2 is a cross-sectional view taken along line A-A
in FIG. 1;
FIG. 3 is a perspective view illustrating an example
of the optical fiber ribbon according to the embodiment of
the present invention;
FIG. 4(a) is a cross-sectional view perpendicular to
a longitudinal direction of the optical fiber ribbon during
single core separation of a comparative example;
Fig. 4(b) is a cross-sectional view of the optical
fiber ribbon following Fig. 4(a) during the single core
separation of the comparative example;
FIG. 5 is a cross-sectional view perpendicular to a
longitudinal direction of the optical fiber ribbon during
single core separation according to the embodiment of the
present invention;
FIG. 6 is a cross-sectional view of the optical fiber
ribbon following Fig. 5 during the single core separation
according to the embodiment of the present invention;
FIG. 7 is a table presenting examples of crosssection
exposure angles and coating removal times according
to a third example of the embodiment of the present
invention.
FIG. 8 is a cross-sectional view perpendicular to a
longitudinal direction of the optical fiber ribbon
according to the other embodiment of the present invention;
and
FIG. 9 is a cross-sectional view perpendicular to a
longitudinal direction of the optical fiber ribbon during
single core separation according to the other embodiment of
the present invention.
DESCRIPTION OF EMBODIMENTS
Various embodiments of the present invention will be
described with reference to the accompanying drawings. In
the following description of the drawings, same or similar
parts are given same or similar reference numerals.
However, it is noted that the drawings are schematic and
that the relationship between thickness and planar
dimensions, the proportion of thicknesses of layers, and
the like are different from real ones. Accordingly,
specific thicknesses and dimensions should be determined
with reference to the following description. It is certain
that some portions have different dimensional relations and
proportions between the drawings.
4
Also, the following embodiments show devices and
methods to embody the technical idea of the invention by
way of example. The technical ideas of the invention do
not limit the materials, shapes, structures, arrangements,
and the like of the constituent components to those
described below. The technical idea of the invention can
be variously changed within the scope of the claims.
As shown in FIG. 1, an optical fiber ribbon according
to an embodiment of the present invention includes a
plurality of (four) optical fiber cores 10a to 10d
extending in parallel and spaced from each other, coating
portions 21a to 21d covering outer circumferences of the
optical fiber cores 10a to 10d, respectively, and a tape
forming member (outer coating) 20 having coupling portions
22a to 22f, which are integrally formed with the coating
portions 21a to 21d and intermittently couple the adjacent
optical fiber cores 10a to 10d, respectively. In addition,
although not shown in FIG. 1, each of the coating portions
21a to 21d of the tape forming member 20 has an opening
portion so as to expose a part of a surface of each of the
optical fiber cores 10a to 10d.
As shown in FIG. 2, the optical fiber cores 10a, 10b
have cores 11a, 11b and clads 12a, 12b which are made of
quartz, coating layers 13a, 13b made of ultraviolet curing
resin covering outer circumferences of the clads 12a, 12b,
and colored layers 14a, 14b made of ultraviolet curing
resin covering outer circumferences of the coating layers
13a, 13b, respectively. The optical fiber cores 10c, 10d
shown in FIG. 1, also have the same structures as the
optical fiber cores 10a, 10b. Hereafter, description will
be given by focusing attention on the optical fiber cores
10a, 10b.
For the material of the tape forming member 20, not
only an ultraviolet curing resin, such as urethane acrylate,
epoxy acrylate and the like, but also a thermoplastic resin,
a thermo-setting resin or the like may be used. A
thickness of the coupling portion 22a of the tape forming
member 20 may be thicker or thinner than each thickness of
the coating portions 21a, 21b. The thickness of the
coupling portion 22a is about 1 􀁐m to about 120 􀁐m, and
each thickness of the coating portions 21a, 21b is about 1
􀁐m to about 15 􀁐m.
As shown in FIGs. 2 and 3, the coating portions 21a,
21b of the tape forming member 20 have opening portions 31
to 35 to expose a part of the surfaces of the colored
layers 14a, 14b of the optical fiber cores 10a, 10b.
Shapes, sizes, layout patterns, numbers and the like of the
5
opening portions 31 to 35 are not limited in particular.
Each shape of the opening portions 31 to 35 may be elliptic
as shown in FIGs. 2 and 3, and may be circular or
rectangular. Also, when each shape of the opening portions
31 to 35 is an ellipse having a major axis in a
longitudinal direction of the optical fiber cores 10a, 10b,
the major axis is, for example, about 10 􀁐m to about 500 􀁐m.
The opening portions 31 to 35 in FIGs. 2 and 3, are
illustrated as being provided irregularly, however the
opening portions 31 to 35 may be provided regularly. For
example, the opening portions may be provided􃻌in a linear
shape or a spiral shape in the longitudinal direction of
the optical fiber cores 10a, 10b periodically with an equal
interval.
Additionally, for an appearance pattern of the
opening portion in the longitudinal direction per each
single core of the optical fiber cores, it is preferable to
be at least one for each coating removal length (for
example, 5 cm) after the single core separation.
Moreover, the opening portions 31 to 35 may be
provided as being biased to one side of each surface of the
coating portions 21a, 21b, or may be provided on both sides
in the longitudinal direction of the optical fiber cores
10a, 10b so as to be not biased to the one side.
Furthermore, an angle (cross-section exposing angle)
􀁔 for exposing the surfaces of the optical fiber cores 10a,
10b through the opening portions 31 to 35, is preferably
larger in view of reducing the coating removal times after
the single core separation. The cross-section exposing
angle 􀁔 is preferably 15􀁱 or more, and it is possible to
significantly reduce the coating removal times after the
single core separation when the cross-section exposing
􀁄􀁑􀁊􀁏􀁈􀀃􀈙􀀃􀁌􀁖􀀃􀀔􀀘􀁱 or more. Also, the cross-section exposing
angle 􀁔 is preferably 270􀁱 or less, in order to secure the
separation strength of the coupling portion 22a. Note that
the cross-section exposing angle 􀁔 is defined as an angle
between two straight lines that connect the centers of the
optical fiber cores 10a, 10b to the ends of the opening
portions 31 to 35 in the widest portions of the opening
portions 31 to 35 in the circumferential direction.
The coating portions 21a, 21b are provided without
discontinuity in the longitudinal directions of the optical
fiber cores 10a, 10b, and at least a part of the coating
portions 21a, 21b is continuous in the longitudinal
directions of the optical fiber cores 10a, 10b. That is,
in any cross-section perpendicular to the longitudinal
directions of the optical fiber cores 10a, 10b, a part or
6
all of the surfaces of the colored layers 14a, 14b are
covered by the coating portions 21a, 21b.
Here, description of comparable example will be given
with reference to FIGs. 4(a) and 4(b). In an optical fiber
ribbon, as shown in FIG. 4(a), in which adjacent optical
fiber cores 101 are arranged in parallel spaced from each
other and integrally formed by the tape forming member
having coating portions 102 for covering the optical fiber
cores 101 and coupling portions 103, cutting is carried out
at the coupling portion 103 when separating into single
cores, as shown in FIG. 4(b). As a result, since the
coating portion 102 of the tape forming member covers the
entire circumference of each optical fiber core 101, it is
difficult to remove the coating portion 102, even if the
adhesion between the surface of the optical fiber core 101
and the coating portion 102 is made poor.
On the contrary, in the optical fiber cores 10a, 10b
according to the embodiment of the present invention, as
shown in FIGs. 2 and 3, the opening portions 31 to 35 are
provided on the coating portions 21a, 21b of the tape
forming member 20 preliminarily prior to the single core
separation, and a part of the surfaces of the colored
layers 14a, 14b of the optical fiber cores 10a, 10b are
exposed. Therefore, as shown in FIG. 5, after the coupling
portion 22a has been cut away during the single core
separation, the coating portions 21a and 21b may be easily
peeled off from the opening portions 31 to 35 when rubbing
the coating portions 21a, 21b by a removing tool having a
abrasive paper or a brush portion, and thus, it is possible
to easily remove the coating portions 21a, 21b as shown in
FIG. 6.
(Manufacturing Method of Optical Fiber Ribbon)
As an example of a manufacturing method of the
optical fiber ribbon according to the embodiment of the
present invention, a plurality of optical fiber cores 10a
to 10d are run in parallel to each other, and an
ultraviolet curing resin is coated on predetermined
positions. Then, the ultraviolet curing resin is cured by
irradiating ultraviolet, and thereby coupling portions 22a
to 22f intermittently fixing the adjacent optical fiber
cores 10a to 10d and the coating portions 21a to 21d
covering the optical fiber cores 10a to 10d are formed.
Here, by adjusting the supply amount of the
ultraviolet curing resin applied to the optical fiber cores
10a to 10d, it is possible to form opening portions 31 to
35 on the coating portions 21a to 21d.
7
Also, shapes, sizes, layout patterns, numbers and the
like of the opening portions 31 to 35 may be arbitrarily
controlled by adjusting the supply amount of the
ultraviolet curing resin applied to the optical fiber cores
10a to 10d or adjusting a shape of a coating dice or a
shutter, and the like.
(First Example)
As a first example, by using colored optical fiber
cores each having a diameter of 250 􀁐m, an intermittently
fixed type optical fiber ribbon (sample A) having four
cores in which opening portions have been provided in
coating portions of a tape forming member so as to expose a
part of each colored layer of the colored optical fiber
cores, has been prepared. Moreover, as a comparative
example, an intermittently fixed type optical fiber ribbon
(sample B) having four cores in which coating portions of a
tape forming member have covered the entire circumference
without exposing colored layers of the colored optical
fiber cores, has been prepared.
The single core separation of the prepared samples A,
B has been performed. After the single core separation,
the optical fiber cores have been rubbed using an abrasive
paper (micro poly-net sheet WA-600 (particle size 20 􀁐m),
made by KOYOSHA INK), and a number of times of rubbing
until the removal of the tape forming member have been
measured.
As a result of the measurement, the sample A has been
3 times and the sample B has been 15 times, and it has been
found that the sample A is easy to remove the tape forming
member in comparison to the sample B.
(Second Example)
By applying alcohol on the same abrasive paper in the
first example, the tape forming member has been removed for
the samples A, B similar to the first example, and a number
of times of rubbing until the removal of the tape forming
member have been measured.
As a result of the measurement, in the sample A, the
number of times of rubbing the optical fiber core has been
reduced by an average of about 12 times in comparison to
the sample B. It is considered that this is because the
colored layer and the coating portion have become more
easily peeled off by swelling due to the alcohol soaking
from an exposed portion of the colored layer where a part
of the coating portion has been peeled off during the
single core separation.
8
(Third Example)
For the sample A similar to the first example, which
has been prepared by changing an exposing angle (crosssection
exposing angle) of the opening in the coating
portion to 90􀁱 and􃻌 15􀁱, the coating removal times of the
tape forming member have been measured after the single
core separation, together with the sample B (the crosssection
exposing angle is 0􀁱) similar to the first example.
As a result, it has been found that, as the cross-section
exposing angle is wider, the coating removal times of the
tape forming member is reduced, as shown in FIG. 7. In
particular, it has been found that, when the cross-section
exposing angle is 15􀁱 or more, the coating removal times of
the tape forming member is dramatically reduced.
(Other Embodiment)
The present invention has been described through the
embodiment as mentioned above. However the descriptions
and drawings that constitute a portion of this disclosure
should not be perceived as limiting this invention.
Various alternative embodiments and operational techniques
will become clear to persons skilled in the art from this
disclosure.
For example, description has been given using the
optical fiber ribbon having four cores in the embodiment of
the present invention. However, the number of the optical
fiber cores composing the optical fiber ribbon is not
particularly limited. Also, the size and kind of the
optical fiber core are not particularly limited. For
example, a structure that does not have the colored layers
14a, 14b of the optical fiber cores 10a, 10b may be used.
Also, pitches and arrangement positions of the coupling
portions 22a to 22f are not particularly limited.
Additionally, it may be possible to produce as an
optical fiber cable by surrounding the outer circumferences
of the optical fiber cores 10a to 10d with cushioning
material, such as jelly, yawn and the like, and coating the
optical fiber cores 10a to 10d simultaneously together with
this cushioning material by a coating layer. The optical
fiber ribbon and the optical fiber cable according to the
present invention may be used for information communication,
and also may be applied to a variety of optical fibers,
such as a single mode fiber, a dispersion shifted fiber and
the like.
Moreover, as shown in FIG. 3, the coating portions
21a, 21b covering the optical fiber cores 10a, 10b have
uniformly smooth surfaces. However, the coating portions
9
21a, 21b may have are irregularly uneven surfaces, as shown
in FIG. 8.
Moreover, as shown in FIG. 5, the coupling portion
22a between the coating portions 21a, 21b has been cut away
during the single core separation. However, as shown in
FIG. 9, a part of the coating portion 21a may be cut away
during the single core separation without cutting the
coupling portion 22a, caused by the thickness of the
coupling portion 22a, the thicknesses of the coating
portions 21a, 21b, the positions of the openings 31, 32,
and the like.
􃻌 In this manner, the present invention naturally
includes various embodiments not specifically mentioned
herein. Accordingly, the technical scope of the present
invention may be limited only by the inventive features set
forth by the scope of the patent claims deemed reasonable
from the above description.

I/We Claim:
1. An optical fiber ribbon comprising:
A plurality of optical fiber cores arranged in
parallel spaced from each other; and
a tape forming member having a coating portion
covering an outer circumference of the optical fiber cores,
and a coupling portion, integrally formed with the coating
portion, intermittently coupling adjacent optical fiber
cores,
wherein the coating portion has an opening portion to
expose a part of surfaces of the optical fiber cores, and
at least a part of the coating portion is continuous in a
longitudinal direction of the optical fiber cores.
2. An optical fiber cable implementing the optical fiber ribbon of claim 1.