JP2000131577A - Optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To substantially prevent a buckling of optical fiber cable even if this cable is bent. SOLUTION: Coated optical fibers 1 are formed in a ribbon form by lining up plural pieces of optical fibers in parallel and applying a coating of a resin thereon. An optical fiber ribbon laminate is formed by laminating plural sheets of such optical fiber coated optical fibers 1. The outer periphery of the optical fiber ribbon laminate is coated with a coating layer 2 consisting of the resin, by which the optical fiber ribbon laminate is integrated. The outer periphery of such laminate is extrusion coated with the thermoplastic resin to form a sheath 3. A thick tape-like intervention 4 is disposed longitudinally between the layers or at the end face of the coated optical fibers 1 of the optical fiber ribbon laminate of such optical fiber cable to suppress the tendency of the respective coated optical fibers 1 to obliquely tilt when the cable is bent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cable having an optical fiber tape laminate formed by laminating a plurality of optical fiber ribbons as a cable core.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view of a conventional optical fiber cable. In FIG. 5, 1 is an optical fiber ribbon, 2 is a coating layer, and 3 is a jacket. The optical fiber ribbon 1 is an optical fiber 1 coated with an ultraviolet curable resin.
a are arranged in parallel (usually, any of 2, 4, 5, 8, 12, and 16), and a UV-curable resin layer 1b is further applied thereon to form a tape. A plurality of such optical fiber tape cores 1 are laminated to form an optical fiber tape laminate, and while the optical fiber tape laminate is twisted, the outer periphery thereof is cured with a thermosetting resin such as silicone or an ultraviolet ray such as urethane acrylate. The optical fiber tape laminate is integrated by coating with a coating layer 2 made of a curable resin, a thermoplastic resin such as nylon, ethylene-vinyl acetate copolymer or the like. An outer jacket 3 is formed by extrusion-coating a thermoplastic resin such as polyethylene or polyvinyl chloride on the outer periphery.

[0003]

However, in the above-mentioned conventional optical fiber cable, since the optical fiber tape laminate is twisted, when the cable is bent, the optical fiber ribbon 1 on the end face side of the laminate is bent. There is a problem in that the distortion of the outer optical fiber increases and the transmission characteristics deteriorate. Further, if a cable is formed without twisting the optical fiber tape laminate to avoid this, buckling is likely to occur, which leads to a reduction in transmission characteristics.

[0004] That is, if the optical fiber tape laminate is twisted, when the cable is bent, a portion where the cross section of the optical fiber tape laminate becomes oblique with respect to the bending direction occurs. The distance from the center to the optical fiber at both the inner and outer ends increases, and the strain force applied to the optical fiber increases accordingly. As a result, when distortion occurs in the optical fiber, transmission characteristics deteriorate.

On the other hand, when a cable is formed without twisting the optical fiber tape laminate, the optical fiber tape laminate is integrated by the covering layer 2 covering the outer periphery thereof, and the length of one rectangular cross section is increased. It can be regarded as a shaku.
Therefore, when a bending force is applied to the cable, it becomes easy to bend in a direction in which the width of the rectangular cross section is small. That is, as shown in FIG. 5, in the case of an optical fiber cable having an optical fiber tape laminate in which ten eight optical fiber ribbons 1 are laminated, as shown in FIG. It becomes easy to bend.

When the cable bends in the direction of arrow A, the optical fiber 1a-IN inside the bend of each optical fiber ribbon 1 receives a compressive force in the longitudinal direction, and the optical fiber 1a outside the bend. -OUT is subject to extension in the length direction. As a result, each laminated optical fiber ribbon 1
In this case, the inside of the bend moves in the lateral direction (the direction of arrow B), and the optical fiber ribbon 1 tends to tilt obliquely. When the bending of the cable exceeds a certain level, buckling occurs.

[0007] The present invention solves such a problem, and by forming a cable without twisting the optical fiber tape laminate, it is possible to prevent the optical fiber from being excessively strained even if the cable is bent. However, it is an object of the present invention to prevent buckling from occurring even when the optical fiber cable is greatly bent.

[0008]

According to a first aspect of the present invention, there is provided an optical fiber cable comprising a plurality of optical fibers arranged in parallel, the outer circumference of which is integrally coated with a resin. In contact with the optical fiber tape laminate in which a plurality of wires are laminated, a thick tape-shaped interposition is disposed in the longitudinal direction, and the optical fiber tape laminate and the interposition are interposed in a state where the optical fiber tape laminate is not twisted. It is characterized in that a coating layer made of resin is provided thereon. In this way, buckling is less likely to occur even if the optical fiber cable is bent significantly, while preventing the optical fiber from being subjected to too much distortion even if the cable is bent.

The optical fiber cable according to the present invention is characterized in that the interposition is arranged in parallel with the plane of the laminated optical fiber tape. In this case, buckling can be effectively prevented.

The optical fiber cable according to claim 3 is characterized in that the interposition is arranged on both end faces of the optical fiber tape laminate. In this case, the occurrence of buckling can be more effectively prevented.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of the present invention. The reference numerals correspond to those in FIG. 5, and 4 is intervening. The coating layer 2 and the jacket 3 can be formed of the same material as that of the above-described conventional optical fiber cable.

The interposition 4 is made of a metal such as steel or copper, nylon,
It is made of a plastic such as polyester or polyethylene, a fiber reinforced plastic reinforced with glass fiber, carbon fiber, aramid fiber, or the like, and is formed in a thick tape shape, which is housed in the center of the optical fiber tape laminate. In this embodiment, the interposition 4 is constituted by one tape. However, the interposition 4 may be formed by laminating a plurality of tapes, or a plurality of the tapes may be an optical fiber ribbon of an optical fiber tape laminate. It may be provided separately at a plurality of locations between the two.

An optical fiber tape core 1 is laminated on both sides of the interposition 4 as a center to form an optical fiber tape laminate, and the outer periphery is covered with a coating layer 2 without twisting the optical fiber tape. The top is covered with a jacket 3. In this case, the optical fiber ribbon 1 has eight cores and a cross-sectional size of about 2.1 mm × about 0.3 mm, and the interposition 4 is made of polyethylene.
And the width were the same, and the thickness was tripled to about 2.1 mm × about 0.9 mm. Optical fiber ribbons 1 on both sides of the interposition 4
Were laminated five by one. The outer periphery was covered with a coating layer 2 made of an ethylene-vinyl acetate copolymer, and further covered with a jacket 3 made of polyethylene.

As described above, by providing the thickened tape-shaped interposition 4 having a certain mechanical strength in the optical fiber tape laminate in parallel with the optical fiber tape core wire 1, each optical fiber cable has Even if bending in the width direction of the fiber ribbon 1 is applied, the bending is suppressed by the interposition 4. Also, even if a large bending force is applied and the optical fiber cable is bent to some extent,
The lateral movement of the inner portion in the bending direction of the optical fiber ribbon 1 is restricted, and each optical fiber ribbon 1 is less likely to be inclined, and buckling is less likely to occur.

FIG. 2 is a diagram showing a second embodiment of the present invention. The reference numerals correspond to those in FIG. 1, and 5 is intervening. In this embodiment, the interpositions 5 and 5 are provided at both ends in the thickness direction of the optical fiber tape laminate. Examples of the material of the interposition 5 include metals such as steel and copper, plastics such as nylon, polyester, and polyethylene;
Fiber reinforced plastics reinforced with glass fibers, carbon fibers, aramid fibers, or the like can be used.

In this case, the optical fiber ribbon 1 is the same as in the first embodiment, the interpositions 5 and 5 are made of polyethylene, and the cross-sectional size is about 2.1 mm × about 0.5 mm.
Both ends of ten laminated optical fiber ribbons 1 were sandwiched between their intervening parts 5,5. The outer periphery was covered with the same coating layer 2 and outer jacket 3 as described above.

As described above, by providing the interpositions 5 and 5 at both ends of the optical fiber tape laminate in parallel with the optical fiber tape 1, the optical fiber cable is bent in the width direction of each optical fiber tape 1. , Bending is suppressed by the interpositions 5 and 5. Then, even if the optical fiber cable is bent to a certain degree by applying a larger bending force, the optical fiber cable 1 is sandwiched by the interpositions 5 and 5 at both ends, and the inner side portion of the optical fiber ribbon 1 in the bending direction does not move in the lateral direction. Due to the strong regulation, the optical fiber ribbons 1 are less likely to be slanted and buckling is less likely to occur. In addition, intervention 5
It is not always necessary to provide them at both ends of the optical fiber tape laminate, and a certain effect can be obtained by providing them only at one end.

FIG. 3 is a diagram showing a third embodiment of the present invention. The reference numerals correspond to those in FIG. 1, and 6 is an intervening. In this embodiment, the interpositions 6, 6 are provided at both ends in the width direction of the optical fiber tape laminate so as to be perpendicular to the respective optical fiber ribbons 1. As the material of the interposition 6, a metal such as steel or copper, a plastic such as nylon, polyester, or polyethylene, a fiber reinforced plastic reinforced with glass fiber, carbon fiber, aramid fiber, or the like may be used as in the above. it can.

In this case, the optical fiber ribbon 1 is the same as in the above embodiments, and the interpositions 6, 6 are made of polyethylene, and the cross-sectional size is about 2.1 mm × about 0.5 mm. That is, the thickness of the laminated body in which ten optical fiber ribbons 1 are laminated is about 3 mm, and both ends in the width direction are sandwiched between the interpositions 6, 6 having a width of about 0.7 times the width. The outer periphery was covered with the same coating layer 2 and outer jacket 3 as described above.

As described above, even if the interpositions 6, 6 are provided at both ends in the width direction of the optical fiber tape laminate so as to be perpendicular to the optical fiber tape core 1, the respective optical fiber tape cores can be attached to the optical fiber cable. When bending in the width direction of line 1,
The bending is suppressed by the interpositions 6,6. Then, even if the optical fiber cable is bent to some extent by applying a larger bending force, the movement of the optical fiber ribbon 1 is suppressed by the interpositions 6 and 6, so that buckling hardly occurs. In addition, the interposition 6 does not necessarily need to be provided on both side ends of the optical fiber tape laminate, and a certain effect can be obtained even if it is provided on only one side.

Further, the interpositions 4, 5 and 6 of the above embodiments may be provided in combination. For example, even when the interposition 5 of the second embodiment and the interposition 6 of the third embodiment are combined as shown in FIG. 4, the occurrence of buckling can be prevented. In addition, the intervention 4 of the first embodiment and the intervention 6 of the third embodiment can be combined, or the intervention 4 of the first embodiment and the intervention 5 of the second embodiment can be combined.

In each of the above embodiments, the interpositions 4, 5,
Although specific examples of the material and size of No. 6 were shown,
The optimum material and size can be appropriately selected according to the structure of the optical fiber cable to be applied and the like.

[0023]

Since the present invention is configured as described above, it has the following effects. In other words, the optical fiber cable according to claim 1 is arranged in such a manner that a thick tape-shaped intervention is disposed in the longitudinal direction in contact with the optical fiber tape laminate, and the optical fiber tape laminate is not twisted. Layers were provided. As a result, even if the optical fiber cable is bent, buckling is less likely to occur even if the optical fiber cable is bent significantly.

In the optical fiber cable according to the present invention, the interposition is arranged in parallel with the surface of the laminated optical fiber ribbon, so that when the cable is bent, the optical fiber ribbon is slanted. Even if it is inclined, the movement is prevented by the interposition, and the occurrence of buckling can be effectively suppressed.

In the optical fiber cable according to the third aspect of the present invention, the interposition is disposed on both end faces of the optical fiber tape laminate, so that when the optical fiber cable is bent, the optical fiber tape core is inclined obliquely. Even so, since the movement is strongly prevented by being sandwiched by the interposition of both ends, the occurrence of buckling can be more effectively prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the present invention.

FIG. 4 is a diagram showing a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a conventional optical fiber cable.

FIG. 6 is a diagram showing a state where a conventional optical fiber cable is bent.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical fiber ribbon 2 ... Coating layer 3 ... Jacket 4,5,6 ... Intervening

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masami Hara 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. F-term (reference) 2H001 BB16 DD00 KK06 KK07 KK17 KK22 5G313 AA01 AB02 AC04 AD02 AE01 AE02 AE08 AE10

Claims (3)

[Claims] 1. An optical fiber tape laminate comprising a plurality of optical fiber ribbons each having a plurality of optical fibers arranged in parallel and having an outer periphery integrally coated with a resin, and having a thick tape-like interposition. An optical fiber cable which is provided in a longitudinal direction, and in which a coating layer made of resin is provided on an optical fiber tape laminate and an interposition thereof without twisting the optical fiber tape laminate. 2. The interposition according to claim 1, wherein the interposition is arranged in parallel with the plane of the laminated optical fiber ribbon.
Optical fiber cable as described. 3. The optical fiber cable according to claim 2, wherein the interposition is disposed on both end faces of the optical fiber tape laminate.