JP2005037641A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable on which large transmission losses are not brought even if tension, impact, external force or stress is applied thereto in manufacturing or using the optical fiber cable. <P>SOLUTION: According to this invention, an optical fiber cable formed by twisting a plurality of optical fibers and a reinforcing material together and covering them with an outer jacket around them, is characterized in that a bundle of aramid fibers is laid at the center part of the optical fiber cable as a center interjacent material; a 1st aramid fiber layer is formed by spirally winding a plurality of aramid fiber bundles around the aramid fiber bundle as the center interjacent material; a 2nd aramid fiber layer is formed by spirally winding a plurality of aramid fiber bundles and a plurality of optical fibers around the 1st aramid fiber layer in the opposite spiral winding direction of the 1st aramid fiber bundle; and in the 2nd aramid fiber layer, the plurality of optical fibers are buried separately without contacting with each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical fiber cable, for example, an optical fiber cable that can transmit and receive a high-speed and large-capacity signal with low loss between a display of a large television set and a tuner.

  In recent years, for example, an optical fiber cable has been used when high-speed and large-capacity signal transmission exceeding 1 Gbps (gigabit per second) is performed between a tuner and a display of a large television set. For this optical fiber cable, an optical fiber cable formed by twisting plastic optical fibers instead of a glass-based optical fiber is preferably used from the viewpoints of handling work of optical fibers or flexibility. It has been.

  When manufacturing an optical fiber cable by converting such an optical fiber into a cable, in order to improve pressure resistance and flex resistance, and to protect the optical fiber from tension, impact or external force, as a reinforcing member, that is, a tension member, As an example of this, an optical fiber cable is arranged at the center of an optical fiber cable, and an aramid fiber is vertically attached as an intermediate material around the optical fiber cable. . (For example, see Patent Document 1)

  However, for example, when an optical fiber cable is manufactured by twisting an optical fiber as shown in Patent Document 1 and an aramid fiber as an intermediary material, the optical fibers that are cabled at the time of manufacture are brought into contact with each other and slid. There is a problem that the optical fiber is stressed due to movement, twisting or bending of the optical fiber, resulting in an increase in transmission loss of the optical fiber.

In addition, in such an optical fiber cable, when the cable is bent during use, the optical fiber core wires at the center of the cable may be in contact with each other while sliding to be stressed. There is a problem that the transmission loss increases.
JP 2003-140013 A

  The present invention has been made in view of the above-described problems, and its purpose is to transmit a large amount of light even when tensile, impact, external force or stress is applied during manufacture of an optical fiber cable or use of an optical fiber cable. An object of the present invention is to provide an optical fiber cable that does not cause loss.

  The above objective is accomplished by an optical fiber cable according to the present invention. That is, the present invention relates to an optical fiber cable formed by twisting a plurality of optical fibers and a reinforcing material and covering the periphery thereof with an aramid fiber bundle as a central intermediary material at the center of the optical fiber cable. And a plurality of aramid fiber bundles are spirally wound around the central aramid fiber bundle to form a first aramid fiber layer, and around the first aramid fiber layer, A plurality of aramid fiber bundles and a plurality of optical fibers are spirally wound together in a direction opposite to the spiral winding direction of the first aramid fiber bundle to form a second aramid fiber layer, and In the second aramid fiber layer, the plurality of optical fibers are embedded separately from each other without contacting each other.

  According to the optical fiber cable of the present invention, in an optical fiber cable formed by twisting a plurality of optical fibers and a reinforcing material and covering the outer periphery thereof, the central portion of the optical fiber cable is used as a central intermediary material. An aramid fiber bundle is arranged, a plurality of aramid fiber bundles are spirally wound around the aramid fiber bundle of the central intermediary material to form a first aramid fiber layer, and further, the first aramid fiber layer Around the periphery, a plurality of aramid fiber bundles and a plurality of optical fibers are spirally wound together in a direction opposite to the spiral winding direction of the first aramid fiber bundle to form a second aramid fiber layer In addition, since the plurality of optical fibers are embedded in the second aramid fiber layer without being brought into contact with each other, they are embedded in the second aramid fiber layer at the time of manufacturing the optical fiber cable or the optical fiber. Even if an optical fiber is pulled, impact, external force, or stress is applied to the optical fiber, the aramid fiber bundle or the aramid fiber layer functions as a buffer to absorb the stress applied to the optical fiber, resulting in a large transmission loss. There is no invitation.

  In addition, the second aramid fiber layer is formed by spirally winding the aramid fiber bundle and the plurality of optical fibers together in a direction opposite to the spiral winding direction of the aramid fiber bundle forming the first aramid fiber layer. Since they are formed, the winding directions are canceled out, and the optical fiber cable is not twisted.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of an optical fiber cable according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a preferred embodiment of an optical fiber cable according to the present invention.
Referring to FIG. 1, there is shown an optical fiber cable 10 according to the present invention that is used to perform high speed and large capacity signal transmission between a tuner and display of a large television set. As shown in FIG. 1, an aramid fiber bundle 20, which is one of tensile strength fibers, is disposed at the center of the optical fiber cable 10 as a central intermediary material. This aramid fiber bundle 20 is formed by bundling four bundles (1420 denier per bundle) of aramid fiber Kevlar (registered trademark of DuPont) and having an outer diameter of about 0.9 mm. Has a tensile strength function against the overall tension.

  Around the aramid fiber bundle 20, a plurality of aramid fiber bundles 30 are twisted at a twist pitch of 98 mm to be right-twisted (Z-twisted) (in this embodiment, as a plurality of aramid fiber bundles, six bundles per bundle 1420 denier), that is, six aramid fiber bundles 30 are spirally wound around the aramid fiber bundle 20 to form a first aramid fiber layer 35.

  Further, around the first aramid fiber layer 35, a plurality of aramid fiber bundles 40 together with the plurality of optical fibers 50 are spirally wound in the aramid fiber bundle 30 in the first aramid fiber layer 35. In the opposite direction to the left twist (S twist) at a twisting pitch of 168 mm (in this embodiment, 8 bundles as a plurality of aramid fiber bundles: 3300 denier per bundle, 4 strands as a plurality of optical fibers) In other words, eight aramid fiber bundles 40 are spirally wound around the aramid fiber layer 35 to form a second aramid fiber layer 45. At that time, the aramid fiber bundle 40 forming the second aramid fiber layer 45 is composed of two bundles of four optical fibers 50 arranged substantially concentrically, as can be easily understood from FIG. It is arranged so as to be sandwiched between. The optical fiber 50 is made of Lucina (registered trademark of Asahi Glass Co., Ltd.) made of an amorphous fluorine polymer and having an outer diameter of 0.5 mm. The optical fiber 50 thus formed by being embedded in the second aramid fiber layer 45 has an outer diameter of about 2.1 millimeters.

  With this configuration, when the optical fiber 50 and the aramid fiber bundle 40 are used to form a cable, the aramid fiber bundle 40, which is a tensile strength fiber, emits light from, for example, unnecessary tension generated in the twisting process. The fiber can be protected so that the optical fiber 50 is not directly tensioned. In other words, the optical fiber 50 is hardly subjected to stress in the manufacturing process, and thus transmission loss during manufacturing is not increased.

  The first and second aramid fiber layers 35 and 45, together with the central intermediate member 20, are reinforced to protect the optical fiber 50 from bending stress, twisting, pulling, impact, external force, stress, and the like from the outside. As a result, the transmission loss of the optical fiber 50 can be minimized.

  Around the second aramid fiber layer 45, a presser made of Gore-Tex (WL Gore registered trademark) tape having a thickness of about 0.1 mm so that the aramid fiber bundle 40 or the optical fiber 50 is not scattered. The winding tape 60 is wound to have an outer diameter of about 2.3 millimeters. Since this press roll tape 60 of Gore-Tex (registered trademark of W.L. Gore) is made of expanded porous PTFE (polytetrafluoroethylene), a hot-melt resin is formed around the press roll tape 60 in the next step. When the cable covering portion 70 is formed as a jacket, the function as a heat-insulating layer having a heat resistance is exhibited, and an optical fiber cable is manufactured using an optical fiber, particularly a plastic optical fiber having a low melting point. Sometimes it is effective to eliminate the heat effect of the molten resin.

  As described above, the cable covering portion 70 is formed around the presser winding tape 60 by extrusion-coating a vinyl chloride resin, which is a heat-meltable resin, with a thickness of 0.3 millimeters as an outer cover. A 2.9 millimeter fiber optic cable 10 is formed. It goes without saying that other thermoplastic polymers such as polyurethane or polyethylene can be used as the jacket, not limited to the above-mentioned vinyl chloride resin.

  The transmission loss of the optical fiber cable 10 formed in this way is measured with a light source (Anritsu MG9001A), an optical power meter (Ando Electric, AQ-1111) and a sensor (Ando Electric, AQ-1958). Used and measured by the cutback method. As a result, it was confirmed that the transmission loss of this optical fiber cable was 50 dB / km or less for each fiber arranged in the second aramid fiber layer 45, and the transmission loss was sufficiently low.

  For example, it can be used as an optical fiber cable for performing transmission / reception of a high-speed and large-capacity signal such as signal transmission between a display and a tuner of a large television set with low loss.

It is sectional drawing of the optical fiber cable of this invention. Example 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical fiber cable 20 Center material 30 Aramid fiber bundle 35 1st aramid fiber layer 40 Aramid fiber bundle 45 2nd aramid fiber layer 50 Optical fiber 60 Press winding tape 70 Cable coating | coated part

Claims (2)

  In an optical fiber cable formed by twisting a plurality of optical fibers and a reinforcing material and covering the periphery thereof, an aramid fiber bundle is disposed as a central intermediary material at the center of the optical fiber cable, and the center A plurality of aramid fiber bundles are spirally wound around an intermediary aramid fiber bundle to form a first aramid fiber layer, and further, the first aramid fiber layer is formed around the first aramid fiber layer. A plurality of aramid fiber bundles and a plurality of optical fibers are spirally wound together in a direction opposite to the spiral winding direction of the bundle to form a second aramid fiber layer, and the second aramid fiber An optical fiber cable characterized in that the plurality of optical fibers are embedded in a layer so as to be spaced apart from each other without contacting each other. The optical fiber cable according to claim 1, wherein a press-wound tape is wound around the second aramid fiber layer, and a thermoplastic resin is extruded and coated on an outer periphery of the press-wound tape.

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