JPS58211715A - Optical fiber cable - Google Patents

Abstract

PURPOSE:To enable the better protection of an optical fiber against mechanical stress and prevention of the bending thereof as well as the reduction in the weight thereof, by using an acetal resin as a protective jacket for the optical fiber. CONSTITUTION:An optical fiber cable consists of an optical fiber core material 1 coated externally with an optical fiber sleeve material 2 and a cushion material 4 inserted between an optical fiber part 10 coated with a soft polymer 3 on said sleeve material and a jacket 5. The jacket 5 consists of a polyacetal resin alone or a compsn. thereof with glass fibers, carbon fibers or the like. The optical fiber 10 is inserted together with the material 4 in the jacket 5. The jacket may be pleated 6 like 5'. The latter case is effective in improving the resistance to abrasion, the protection of the optical fiber against mechanical strength and the prevention of the bending thereof additionally and effective in enabling the reduction in weight.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acetal resin protected optical fiber cable.

Technology related to optical fibers has advanced rapidly in recent years, and commercialization of optical communication systems has already begun. The medium used for optical communication is optical fiber, which has a core material of highly purified quartz or an organic or inorganic glass-like substance with good transparency.
This is then covered with a transparent material having a lower refractive index to form a sheath material, and the light incident on the end face of the fiber is propagated while undergoing total internal reflection. It is well known that various efforts have been made to improve the transmittance of this core material and reduce light attenuation.

On the other hand, the original glass material is brittle and easily damaged.
The damage also expands due to the mechanical stress caused by deformation, impeding the transmittance, and finally, after many years, it reaches the point where it is cut off.

□ For this reason, coating with organic polymers plays a very important role. That is, it prevents abrasion damage that causes micro-scratches in optical fibers, and protects them from environmental influences that cause stress corrosion of the fibers. Furthermore, it is effective in reducing optical loss due to microbending. For coating with such organic polymers, soft rubber-like polymers such as silicone rubber and ethylene-vinyl acetate are usually effectively used. These coatings use soft polymers to prevent the fibers from becoming uneven, but the coating polymers themselves are susceptible to wear and tear. This is especially noticeable with silicone rubber.

Furthermore, optical fiber itself is quite brittle and cannot withstand bending K with a small curvature. In order to prevent such small curvatures from being carelessly bent, it is necessary to take measures to prevent bending. Moreover, it cannot be said that it is necessarily strong against impact tensile stress. It is also necessary to protect it from such mechanical shocks.

As a result of various studies on optical fiber cables that solved the above-mentioned problems, the inventor of the present invention found that acetal resin was used as a protective jacket for optical fibers &:1:, -b
The inventors have discovered that an optical fiber cable can be obtained that solves the problems described above, and have completed the present invention.

That is, the present invention (d) is a small optical fiber cable protected by a jacket mainly made of polyacetal resin.

The present invention will be explained below with reference to FIG.

FIG. 1 is a perspective view of one embodiment of the optical fiber cable of the present invention. In the figure, 1 is an optical fiber core material, 2 is an optical fiber sheath material, 3 is a soft polymer, 4 is a cushion material, 5 is a jacket, and IO is an optical fiber part. In the figure, the optical fiber cable has an optical fiber sheath material 2 coated on the outer periphery of an optical fiber core material 1, and a cushion material 4 is inserted between an optical fiber portion 10 whose outer periphery is coated with a soft polymer 3 and a jacuit 5. It has a built-in structure. Jaggett 5 is made by combining polyacetal resin, which is often used as an engineering resin in mechanical parts, electronic parts, etc., or by combining the resin with fibrous or particulate fillers such as glass fiber, carbon fiber, aramid fiber, or other inorganic fibers. A boriacetaflu composition consisting of fine particles and the like is manufactured into a tube shape by extrusion processing.

The optical fiber cable is manufactured by inserting the optical fiber portion 10 together with the cushioning material 4 inside the jacket 5.

In the present invention, jackets having shapes as shown in FIGS. 2, 3, and 4 can also be used as the jacket. When a jacket having such a shape is used, it is possible to reduce the weight of the optical fiber table and improve bending resistance and scratch resistance, which is preferable. Further, in the present invention, the thickness of each material used or not used as a cushioning material, and the depth, width, and number of pleats of the pleated jacket may be arbitrarily designed within a range that does not change the gist of the present invention. Furthermore, although an example of a structure using one optical fiber part was shown in No. 1 I￥1, in the present invention, for example, an optical fiber having a structure in which a plurality of optical fiber parts are housed four times in the same jacket. It is also possible to use a cable.

The optical fiber cable of the present invention has effects such as improved abrasion resistance, protection against mechanical stress of optical fibers, and prevention of bending. This has the effect of further improving protection against mechanical stress and preventing bending of optical fibers, and making it possible to reduce the weight.

The optical fiber cable of the present invention can be used by covering one or more cables with rubber, PVC, or other synthetic material.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of one embodiment of the optical fiber cable of the present invention, and FIGS. 2.3 and 4 are cross-sectional views of jackets of other embodiments used in the present invention. 1 in the figure is an optical fiber core material,
2 is an optical fiber sheath material, and 3 is an optical fiber portion made of the soft fiber sheath material 2 and a soft polymer. Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] 1. An optical fiber cable characterized in that it is protected by a jacket mainly made of acetal resin.2 The jacket has a plurality of folds parallel to the outer periphery and the length direction. The optical fiber cable 3 according to claim 1, characterized in that the jacket has a plurality of pleats parallel to the length direction of the inner circumference. An optical fiber cable 4 according to claim 1, wherein the jacket has pleats in the longitudinal direction of the inner and outer circumferences, The acetal resin contains a fibrous or particulate filler. The optical fiber cable according to claim 1, characterized in that it contains