JP2008197258A - Optical cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical cable having high flexibility and handiness for mounting an optical connector and also having a prescribed tensile force. <P>SOLUTION: A coated optical fiber 11, for which an optical fiber 12 composed of fused quartz is coated with coating resin 13a, 13b, is integrated with a cable jacket containing no metallic wire inside, having an outside dimension ≤4 mm on the major side, and forming a rectangular or elliptical cross section. A general tensile strength at the time of 1% elongation of the cable jacket is ≥50 N, with a connecting part for an optical component 9 mounted on the cable jacket at the cable end. In addition, with no shrink resistant member in the cable, the coated optical fiber is desirably structured to have a glass fiber coated with a coating resin having a Young's modulus of 0.1-10 MPa. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical cable used for optical connection (for example, LAN wiring) between information devices.

  With recent advances in optical communication technology, LAN (Local Area Network) wiring using optical communication, wiring between devices, and the like have been adopted. This optical LAN wiring or inter-device wiring is different from optical communication over a long distance, for example, because it is an optical communication over a short distance between devices installed indoors or in a vehicle, so compared with a single mode optical fiber. A multimode optical fiber having superior optical connectivity is often used. Further, these optical cables are required to have high bending performance with respect to wiring in a complicated portion and wiring in an opening / closing portion of a door. In addition, the connection to the device is generally performed using an optical connector. However, the optical connector is often attached at the site, and an optical cable with good attachment to the optical connector is required.

Conventionally, as a drop optical cable or an indoor optical cable 1, for example, as shown in FIG. 6 (A), tension members 3 made of steel wire of about 0.4 mmφ are arranged on both sides of the optical fiber core wire 2, and the entire outer shape is formed. The thing of the structure integrated with the cable jacket 4 so that it may become about 2-4 mm is known (for example, refer patent document 1). It is also known that the steel wire 2 of the tension member 3 is formed of a twisted steel wire obtained by twisting a thin steel wire as shown in FIG. 6 (B). Further, it is also known that the tension member 3 is replaced with a steel wire and a glass fiber, an aramid fiber or the like is solidified and integrated with a resin.
JP 2004-198588 A

  In optical LAN wiring and inter-device wiring, when an optical cable is used across an opening / closing part such as a door, the optical cable is required to have high bending performance. For example, the optical cable is 100,000 at a bending radius R9 mm and 90 ° left and right. The optical cable is required not to be damaged even if it is bent more than once. However, as shown in FIG. 6 (A), when a single-core steel wire is used for the tension member, bending at a bending radius of R9 mm and a right and left of 90 ° causes metal fatigue and breaks about 2000 times. Moreover, even when the tension member is a stranded steel wire as shown in FIG. 6 (B), it is disconnected about 10,000 times. That is, when a metal wire is included in the optical cable, it is difficult to ensure the above bending performance.

It is also known to use a non-metallic material in which a high-strength glass fiber material or an aramid fiber material is hardened with a resin for the tension member of an optical cable, but there is a risk of breaking when bent at a bending radius of about R9 mm. Even if it does not lead to a complete disconnection, the tensile strength decreases. In addition, when a high-strength fiber material is used without being hardened with a resin, there is a problem that when the optical connector is attached to the end of the optical cable, it takes time to process the fiber material and workability is lowered.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an optical cable having high bending performance and simple optical connector attachment and having a predetermined tensile tension.

  An optical cable according to the present invention is an optical fiber core wire in which an optical fiber mainly composed of quartz glass is coated with a coating resin, does not include a metal wire inside, has an outer dimension of 4 mm or less, and has a rectangular cross section. Alternatively, they are integrated with an elliptical cable jacket, and the total tensile tension when the cable jacket is stretched by 1% is 50 N or more, and the connecting portion of the optical component is attached to the cable jacket at the cable end. In addition, it is desirable to use an optical fiber having a configuration in which a coating resin having a Young's modulus of 0.1 MPa to 10 MPa is applied on the glass fiber in a state where the cable has no anti-shrink member.

  If the cable does not include a tension member, the cable jacket is formed of a thermoplastic resin having a Young's modulus of 200 to 1500 MPa. As tension members, high-strength fiber bundles are integrated on both sides of the optical fiber core with a cable jacket at a density such that the force to pull out the high-strength fiber bundle from the cable (withdrawal force) is 50 N / cm to 900 N / cm. May be. Further, as a tension member, a rod-shaped wire material in which a high-strength fiber bundle is hardened with a matrix resin is arranged on both sides of the optical fiber core wire, and the rod-shaped wire material is integrated with the optical fiber core wire. The thickness in the direction orthogonal to the arrangement direction is set to a thickness that can withstand a predetermined bending test. In the bending test, it is desirable that the total tensile tension when the cable jacket extends 1% is 50 N or more after bending 100,000 times under the condition of a radius of curvature of 9 mm and a right and left of 90 °. Furthermore, you may make it use what has electroconductivity for said high-strength fiber bundle.

  According to the present invention, the optical connector has a tensile tension that can sufficiently withstand the tension temporarily applied when laying the optical cable, and does not break in a bending test of 100,000 times under the condition of a radius of curvature of R9 mm and a right and left of 90 °. Therefore, it is possible to provide an optical cable suitable for LAN wiring with good mounting workability.

  Embodiments of the present invention will be described with reference to the drawings. 1A and 1B are diagrams for explaining the outline of an optical cable according to the present invention. FIG. 1A shows an example of an optical cable having a rectangular cross section, FIG. 1B shows an example of an optical cable for LAN having an elliptical cross section, 1 (C) is a diagram showing a state in which an optical connector is attached to an optical cable. In the figure, 9 is an optical connector, 10 is an optical cable, 11 is an optical fiber core wire, 12 is a glass fiber, 13a and 13b are coating layers, 14 is a colored layer, 15 is a tension member, and 16 is a cable jacket.

  An optical cable 10 according to the present invention is an optical cable that optically connects a plurality of information devices installed indoors or in a vehicle, and is relatively short distance (for example, about 1 m to 20 m) between LANs and devices. The target is an optical cable (LAN optical cable) suitable for use in wiring or the like. For example, as shown in FIG. 1 (A), this type of optical cable 10 has optical fiber cores 11 arranged in a line and a cable jacket 16 with or without tension members 15 disposed on both sides thereof. It is formed integrally.

  For the optical fiber core 11, a multimode glass fiber 12 made of quartz glass, having a core diameter of 50 μm and a cladding diameter of 125 μm can be used. In addition, the optical fiber mainly made of quartz glass may be one in which both the core and the clad are made of quartz glass, or only the core is made of quartz glass and the clad is made of hard plastic. There may be.

  The optical fiber core 11 is formed by covering the glass fiber 12 with coating layers 13a and 13b made of an ultraviolet curable acrylate resin and having an outer diameter of about 245 μm, and applying a colored layer 14 to the coating surface. In addition, you may make it form a coating layer by two layers, the primary coating layer 13a and the secondary coating layer 13b. In this case, the Young's modulus of the inner primary coating 13a is made smaller than the Young's modulus of the outer secondary coating 13b so as to provide a buffering action against the side pressure so as to suppress the generation of microbends and maintain good optical transmission characteristics. can do.

  Two or more optical fiber core wires 11 are arranged in a line, and are integrated with a cable jacket 16 with or without tension members 15 disposed on both ends thereof. Here, “integrated with the cable jacket” refers to a state in which the optical fiber core 11 embedded in the cable jacket can directly contact the cable jacket 16 and jointly cope with the tensile stress. As will be described later, the tension member 15 may not be particularly required in a usage mode in which a large tension is not always applied, such as LAN wiring, as long as the tensile tension of the entire optical cable can be secured to a predetermined value or more. .

  The cable jacket 16 is formed of a thermoplastic resin such as nylon resin, polyethylene (PE), polyvinyl chloride (PVC), or the like, for example, in a rectangular or elliptical cross section. The cable jacket 16 is formed by full extrusion. Solid extrusion is a method of performing extrusion while applying pressure to an optical fiber core or the like so as to compress the extruded resin inside the die of the resin extruder. The extruded resin is in a compressed state in the die, and the thermoplastic resin extruded on the outer periphery of the optical fiber core wire 11 can have high adhesion to the optical fiber core wire 11 as the cable jacket 16. it can. The cable jacket 16 is in close contact with the optical fiber core 11 to prevent the optical fiber core 11 from meandering in the cable and increasing loss when the cable jacket 16 contracts. be able to.

  Further, the elongation at break of the optical fiber core 11 is generally 5% or more, but if the stretched state continues even below the elongation at break, static fatigue occurs due to the growth of cracks existing in the glass, and the wire breaks with a certain probability over time. To do. Considering the fracture life of the fiber glass part, it is also important to optimize the screening level at the time of drawing the optical fiber core wire. If this screening level is 1.5%, even if 1% of elongation corresponding to 2/3 of the screening level is added to the optical fiber core when wiring the optical cable, the glass breakage probability after 10 years is 1 million minutes. It can be suppressed to a very low value of 1 or less.

  In the present invention, since the optical fiber and the jacket are integrated, the optical fiber extension and the cable extension are substantially equal. For this reason, by suppressing the cable jacket elongation to 1% or less, the optical fiber elongation can also be suppressed to approximately 1% or less, and the breaking probability of glass can be suppressed to a very low level. Therefore, the total tensile tension when the cable jacket is stretched by 1% means the tensile tension when the cable is gripped and the cable is stretched by 1%, such as an optical fiber integrated with the cable jacket. The tensile tension of the member is also taken into consideration.

It is sufficient for the optical cable 10 to assume that a tensile tension of about 50 N is applied to LAN wiring such as indoors and wiring between devices. Therefore, the optical cable has a tensile strength that can withstand a tension of 50 N (preferably 70 N, which is generally accepted as an allowable tension), as a whole, the optical fiber core wire 11, the tension member 15, and the cable jacket 16 in the cable. I can say that.
Also, as LAN wiring and inter-device wiring, there is a demand for wiring space, handleability, and a thin optical cable. Therefore, in the present invention, the outer dimension of the cable jacket 16 is rectangular or elliptical in cross section of 4 mm or less. (Preferably, a rectangular cross section of 2 mm × 3 mm) has a directivity in the bending direction, and does not include a metal wire that easily causes metal fatigue as a strength member.

  Further, as shown in FIG. 1 (C), the optical cable 10 is often used by attaching a connecting portion of an optical component such as an optical connector 9, a light source module, or a light receiving module to the end portion of the optical cable 10. Good things are needed. For example, with respect to the mountability of the optical connector 9, since the optical fiber core wire 11 and the cable jacket 16 are integrated, the optical connector can be fixed simply by gripping the cable jacket 16, and the workability is simple. It is good. Even if the cable jacket 16 is held and fixed by the optical connector 9, if the Young's modulus of the cable jacket 16 is low, only the cable jacket may be stretched when the optical connector 9 is pulled. For this reason, the cable jacket 16 has a Young's modulus of 200 MPa or more (preferably 300 MPa or more), and the total tensile tension when the cable jacket including the optical fiber core 11 is extended by 1% is a general optical connector. It is desirable that the tension is 50N or more.

  Further, in the optical cable according to the present invention, since the cable jacket 16 and the optical fiber core 11 are integrated, the optical fiber core wire causes microbending at a low temperature and transmission loss tends to increase. For this, a rod-shaped wire (FRP rod) in which high-strength fibers repelling the shrinkage of the cable jacket are hardened with resin is used not only as a tension member (strength member) but also as an anti-shrink member. However, you may make it set it as the form which does not use preferentially the flexibility of a cable.

  When an anti-shrink member is not used, in the optical cable of the present invention, a soft layer (primary coating layer) having a low Young's modulus is formed on the glass fiber of the optical fiber core so that the optical fiber core is less susceptible to microbending. 13a) may be provided. Specifically, by providing a coating layer of 10 MPa or less, which is about two orders of magnitude lower than the Young's modulus of 800 MPa to 1200 MPa used for the outermost layer (secondary coating layer or colored layer 14) of the optical fiber core from the viewpoint of trauma resistance. It is possible to increase the micro bend diameter of the microbend and to maintain good transmission loss even at low temperatures. If the coating layer is too soft, the position of the quartz glass is not stabilized and the eccentricity is deteriorated. Therefore, it is desirable to set the Young's modulus to 0.1 MPa or more.

  With the above-described configuration, it can sufficiently withstand the tension applied temporarily when laying the optical cable, and has a high bending performance that does not cause breakage in a bending test with a radius of curvature of R9 mm and 90 ° left and right at 100,000 times, It is possible to improve the workability of mounting the optical connector.

(Example 1)
FIG. 2 is a diagram for explaining the first embodiment and shows an example in which no tension member is provided in the cable. In Example 1, two optical fiber core wires 11 are arranged in a line and integrated with a cable jacket 16 of 2 mm × 3 mm, and an optical cable having no tension member in the cable jacket is obtained. As the optical fiber core 11, a multi-mode glass fiber having a core diameter of 50 μm and a cladding diameter of 125 μm coated with an ultraviolet curable acrylate resin having an outer diameter of 250 μm was used. This UV curable resin type acrylate resin was obtained by coating a glass fiber of an optical fiber core with a low Young's modulus resin having a Young's modulus of 1 MPa up to 200 μm, and further coating a resin having a Young's modulus of 800 MPa up to 250 μm. The cable jacket 16 was formed by thoroughly extruding a nylon resin having a Young's modulus of 1200 MPa.

  The elongation rigidity of the optical cable of Example 1 will be described. The elongation rigidity is a value represented by the product ES (unit: N) of the Young's modulus E and the cross-sectional area S. In the present invention, assuming that the value at 23 ° C. is used and the glass fiber has a diameter of 125 μm and a Young's modulus of 68.6 GPa, the elongation rigidity of the two glass fiber portions is 1.7 kN. Since the cable jacket 16 has an outer shape of 2 mm × 3 mm and a Young's modulus of 1200 MPa, it is 7.2 kN. If the screening level of the optical fiber core 11 is 1.5%, it can be extended to 1%. Therefore, the total tensile tension when the optical cable jacket is extended by 1% is 89N. The tension can exceed 50N or the general allowable tension 70N.

  However, when the Young's modulus of the cable jacket 16 is increased, the cable bending rigidity is also increased, the cable is hard to be bent, and the cable handling property is also deteriorated. For this reason, it is desirable to suppress the Young's modulus to about 1500 MPa. In order to increase the tensile strength of the cable jacket 16, it is conceivable to increase the cross-sectional area of the cable jacket. However, in consideration of the cable wiring space, the outer dimension of the optical cable may be 4 mm or less. desirable. In consideration of this point, the Young's modulus of the cable jacket 16 needs to be 200 MPa or more in order to set the tensile tension when the cable jacket 1% is stretched to 70 N or more.

  As for the bending performance of the cable, the bending strain applied to the glass fiber portion of the optical fiber core wire 11 when bent at a bending radius R9 mm that is slightly less than 5 times the short side (2 mm width) of the cable cross section (2 mm × 3 mm). Is at most 0.7% and below 1%. Since the life of glass is mainly determined by the accumulated time of strain, the influence of the number of bendings is small, and unlike steel wires that cause metal fatigue, glass is a material that is less susceptible to dynamic fatigue. Even if it is added about 10,000 times (see the bending test example in FIG. 5), the probability of fracture is as low as 1 / million or less, and there is no practical disconnection.

  Further, the breaking elongation of the nylon resin used for the cable jacket 16 is 100%, which is one digit different from the bending strain applied to the cable jacket 16 when bent, and the cable jacket was not damaged such as cracks. Furthermore, in order to prevent the cable jacket from cracking even if it is bent 100,000 times in a reciprocating manner with a bending radius R9mm that is slightly less than 5 times the short side of the cable cross section, at least the breaking extension of the cable jacket should be It has also been found that it may be 100% or more, which is 10 times the maximum strain applied to the cover.

  In the first embodiment, nylon resin is used for the cable jacket 16, but polyurethane resin, polyethylene resin, and the like have a high Young's modulus like the nylon resin, and a wide variety of resins can be selected. In addition, by selecting a resin having a melting point of about 150 ° C., for example, wiring in a high temperature environment of about 125 ° C. such as around an automobile engine is possible.

As a result of performing a temperature test of (−40 ° C. to 125 ° C.) × 3 cycles, the transmission loss increase amount Δα was as good as 0.02 dB / 20 m. If the inner coating immediately above the glass fiber is coated with a soft coating resin having a diameter of 150 μm or more and a Young's modulus of 10 MPa or less, the increase Δα in transmission loss can be suppressed to 0.1 dB / km or less. However, if the Young's modulus is too low, the glass portion of the optical fiber cannot be firmly fixed and the eccentricity becomes high. Therefore, it is desirable that the Young's modulus of the coating resin immediately above the glass fiber is 0.1 MPa or more.
With respect to the mountability of the optical connector, since the optical fiber core 11 of the optical cable 10 and the thermoplastic resin of the cable jacket 16 are closely integrated, the cable jacket 16 can be fixed simply by gripping it with the gripping portion of the optical connector. Can be installed easily.

(Example 2)
FIG. 3 is a diagram for explaining the second embodiment and shows an example in which high-strength fibers are used as tension members in the cable. In this Example 2, the same two optical fiber core wires 11 as used in Example 1 of FIG. 2 are arranged in a line, and high-strength fiber bundles are arranged as tension members 15a on both sides thereof, and 2 mm × 3 mm The optical cable has a shape integrated with the cable jacket 16 of the above. As the optical fiber core 11, a multi-mode glass fiber having a core diameter of 50 μm and a cladding diameter of 125 μm coated with an ultraviolet curable acrylate resin having an outer diameter of 250 μm was used. The cable jacket 16 was formed by full extrusion molding of a soft 100 MPa polyolefin resin.

As the high-strength fiber bundle, PBO (poly-p-phenylene benzobisoxazole) polymer fiber having a Young's modulus of 180 GPa (the diameter when bundled is about 0.4 mm) was used. When full extrusion is performed, the resin pressure can be set as high as 500 MPa at the die and the point portion of the extruder, so that high-strength fibers can be strongly tightened with the resin of the jacket. Thus, even if only the cable jacket is gripped and pulled at the cable end portion, the tension is reliably transmitted to the high-strength fiber bundle. In addition, since micron-order ultrafine high-strength fibers are fastened with a cable jacket, when cutting with a general-purpose tool such as a nipper, the high-strength fibers can be easily cut without being loose. Specifically, the density of the high-strength fiber is about 15,000 dtex / mm ² (13,500 denier / mm ² ).

  In other words, this density is a density at which the force (pulling force) when pulling the high-strength fiber bundle from the cable jacket is 50 N / cm or more. The high-strength fiber does not come out even when the optical connector grips the jacket with a length of about 1 cm and is pulled with a tension of 50 N, so that the tension is reliably transmitted to the high-strength fiber bundle. In addition, the back tension of the high strength fiber at the time of manufacture can be manufactured at a low value of about 2N.

  Regarding the elongation rigidity of the optical cable of Example 2, for example, the elongation rigidity (ES product) of the high-strength polymer fiber bundle is 45 kN, the elongation rigidity of the fiber glass portion is 1.7 kN, and the elongation rigidity of the cable jacket 16 is 0.7. 6 kN. For this reason, for example, even in the case of a low-strength optical fiber core whose screening level is as low as 0.3% and can only be extended to 0.2%, the allowable tension of the optical cable 10 is 94 N, which is normally considered indoors. It is possible to exceed the tensile tension of 50N or the general allowable tension of 70N.

  As for the bending performance of the cable, for example, when the cable is bent to the short side of the cable with a bending radius R9 mm as in Example 1 of FIG. In the case of being completely fixed, the maximum strain of 2% is added. However, since the high-strength fiber bundle is actually only restrained by the soft thermoplastic resin of the cable jacket 16, the high-strength fibers move slightly in the longitudinal direction when the cable is bent, although there is fiber friction. can do. For this reason, even if the cable is bent, the maximum strain generated in the high-strength fiber is more surely relaxed than 2% and is not easily broken. In order to shift the high-strength fibers when the cable is bent, the pulling force of the high-strength fiber bundle is desirably 900 N / cm or less corresponding to the tension at the maximum strain of 2%. Here, the pulling force as a high-strength fiber bundle is described, but the force when pulling out one high-strength fiber or a part of the high-strength fiber is not more than a value obtained by multiplying the cross-sectional area ratio with respect to the high-strength fiber bundle It becomes.

Further, the tension member 15a of Example 2 is a bundle of micron-sized ultrafine fibers and the fibers are independent of each other. Therefore, even if the fiber where the maximum strain occurs is cut, other fibers are cut. It is not greatly affected by the fiber. Moreover, in the present Example 2, although the PBO fiber was shown as an example, high-strength polymer fiber such as aramid fiber, carbon fiber of inorganic fiber, or the like may be used. In addition, since carbon fiber has electroconductivity, it can be made to function as an object for electric power feeding of a light emitting element or a light receiving element. Therefore, the carbon fiber can achieve both bending characteristics and electrical conductivity, which are impossible with a metal wire that undergoes fatigue fracture.
With respect to the mountability of the optical connector, since the optical fiber core wire 11 and the high-strength fiber of the optical cable 10 and the thermoplastic resin of the cable jacket 16 are tightly integrated, the cable jacket 16 is gripped by the grip portion of the optical connector. It can be fixed simply and can be easily installed.

(Example 3)
FIG. 4 is a diagram for explaining a third embodiment, showing an example in which high-strength FRP (Fiber Reinforced Plastics) is used as a tension member in a cable. In this Example 3, the same two optical fiber core wires 11 used in Example 1 of FIG. 2 are arranged in a row, and rod members of high strength FRP are arranged as tension members 15b on both sides thereof, An optical cable having a shape integrated with a cable jacket 16 of 2 mm × 3 mm was obtained. As the optical fiber core 11, a multi-mode glass fiber having a core diameter of 50 μm and a cladding diameter of 125 μm coated with an ultraviolet curable acrylate resin having an outer diameter of 250 μm was used. The cable jacket 16 was formed by full extrusion molding of a soft 100 MPa polyolefin resin.

The high-strength FRP was impregnated with PBO (poly-p-phenylene benzobisoxazole) polymer fiber having a Young's modulus of 180 GPa with a polyester-based resin so as to be a rod-shaped wire having an outer diameter of about 0.4 mm. In addition, as high intensity | strength FRP, glass fiber, carbon fiber, etc. of an inorganic fiber can also be used.
Regarding the elongation rigidity of the optical cable of Example 3 above, since the high-strength fibers having the same material and dimensions are provided as in Example 2 of FIG. 3, the screening level is as low as 0.3% and 0.2%. Even with a low-strength optical fiber that can only be stretched, the allowable tension of the optical cable 10 is 94 N, which can exceed the tension tension of 50 N in ordinary indoor work or the general allowable tension of 70 N.

  As for the bending performance of the cable, since the high-strength fibers are impregnated with the polyester matrix resin, the periphery of the high-strength fiber bundle is suppressed with a soft thermoplastic resin. On the other hand, regarding the bending performance, when the cable is bent, the high-strength fibers move in the longitudinal direction and cannot relax the strain. Therefore, the rod member of high strength FRP is formed with a thickness that can withstand a predetermined bending test in a direction perpendicular to the arrangement direction of the optical fiber core wires (that is, a bending direction on the short side). It is desirable. It should be noted that, as shown in FIG. 5, the total tensile tension when the cable jacket is stretched by 1% is 50 N or more after bending 100,000 times under the condition of 90 ° left and right with a radius of curvature of 9 mm as shown in FIG. Say that.

  When the thickness in the bending direction of the FRP rod-shaped wire is 2 t and the bending radius is R, the thickness of the outermost (innermost) side of the FRP rod-shaped wire is t / (R + t). However, it shall withstand this distortion and have the necessary minimum strength. For example, by making the rod-like member into a flat shape with a reduced thickness in the bending direction, a predetermined tensile tension can be secured and the strain can be reduced.

  Basically, if a high-strength fiber having a breaking elongation of 2% or more is used, breakage due to bending can be prevented. Assuming that a portion of a high-strength FRP rod-shaped member having a large strain is partially broken, the high-strength fibers are not all broken. Although high-strength fibers are integrated with each other through a matrix resin, matrix resin has a modulus of elasticity that is two orders of magnitude lower than that of high-strength fibers and is easily broken. The matrix resin is also destroyed, and high strength fibers not broken do not break at the same time.

  As for the bending performance of the cable, the high-strength fibers are more likely to break than in Example 2 in FIG. 3, but the high-strength fibers having a high Young's modulus are integrated with a matrix resin, so It also functions. For this reason, when used under low temperature, it can resist low temperature shrinkage of a thermoplastic resin having a large linear expansion coefficient, and can reduce an increase in loss due to microbending in the cable of the optical fiber core wire.

The polyester resin impregnated in the high-strength fiber is a thermosetting resin, but an ultraviolet curable acrylic resin or a low viscosity thermoplastic resin may be used as long as it penetrates between the fibers.
With respect to the mountability of the optical connector, since the optical fiber core wire 11 and the high-strength fiber of the optical cable 10 and the thermoplastic resin of the cable jacket 16 are tightly integrated, the cable jacket 16 is gripped by the grip portion of the optical connector. It can be fixed simply and can be easily installed.

(Comparative Example 1)
As shown in FIG. 6 (A), the same two optical fiber core wires 2 as used in Example 1 of FIG. 2 are arranged in a line, and steel members having an outer diameter of 0.4 mm as tension members 3 on both sides thereof. An optical cable having a shape in which wires are arranged and integrated with a cable jacket 4 of 2 mm × 3 mm was obtained. As the optical fiber 2, a multimode glass fiber having a core diameter of 50 μm and a cladding diameter of 125 μm, similar to those of Examples 1 to 3, coated with an ultraviolet curable acrylate resin having an outer diameter of 250 μm was used. The cable jacket 4 was formed by solid extrusion molding of a soft 100 MPa polyolefin resin.

  The Young's modulus of the steel wire of the tension member 3 is larger than that of the PBO fiber, the elongation stiffness (ES product) of the steel wire is 53 kN, and the elongation stiffness of the fiber glass portion is more than an order of magnitude more than 1.7 kN. In the case of a steel wire, the allowable elongation of the steel wire itself is a rule, and the allowable elongation of the cable is only 0.3%. When calculated with an allowable elongation of 0.3%, the allowable tension of the cable is about 160 N, which can exceed the general allowable tension 70 N of the cable used indoors. In the case of a steel wire, since the allowable elongation of the steel wire itself is only 0.3%, there is no point in applying a high-strength optical fiber core with 1.5% screening, for example. Regarding the bendability of the optical cable, as described in the problem section, the steel wire causes metal fatigue, so the bend performance is low. Disconnected at a degree.

(Comparative Example 2)
As shown in FIG. 6 (B), the same two optical fiber core wires 2 used in Example 1 of FIG. 2 are arranged in a line, and steel members having an outer diameter of 0.17 mm as tension members 3 on both sides thereof. A twisted steel wire in which nine wires were twisted was arranged, and an optical cable having a shape integrated with a 2 mm × 3 mm cable jacket 4 was obtained. As the optical fiber 2, a multimode glass fiber having a core diameter of 50 μm and a cladding diameter of 125 μm, similar to those of Examples 1 to 3, coated with an ultraviolet curable acrylate resin having an outer diameter of 250 μm was used. The cable jacket 16 was formed by full extrusion molding of a soft 100 MPa polyolefin resin.

  The elongation rigidity (ES product) of the stranded steel wire of the tension member 3 is 86 kN, and even in the case of the stranded steel wire, the allowable elongation of the stranded steel wire itself is a rule, and the allowable elongation of the cable is only 0.3%. When calculated with an allowable elongation of 0.3%, the allowable tension of the cable is about 260 N, which can exceed the general allowable tension 70 N of the cable used indoors. As for the bendability of the optical cable, as in Comparative Example 1, even when individual steel wires having a thin thickness of 0.17 mm are used, metal fatigue cannot be avoided. The number of times increased, but the wire was still broken by about 10,000 bends.

  Table 1 below shows the cable tension when the optical cables of Examples 1 to 3 and Comparative Examples 1 and 2 described above were bent 100,000 times in a bending test of 90 ° to the left and right at a bending radius R9 mm shown in FIG. Is shown. In Examples 1 to 3, the allowable elongation of the fiber is determined from the viewpoint of the lifetime of the optical fiber, and the cable tension at the time of 10% elongation is shown. In Comparative Examples 1 and 2, the allowable elongation of the steel wire is determined. Therefore, it is shown by the cable tension at 0.3% elongation.

  From the results of Table 1, in Examples 1 to 3 according to the present invention, the cable tension after the bending test is slightly lower than that before the bending test. It exceeds the tensile tension of 50N or the general allowable tension of 70N. On the other hand, in Comparative Examples 1 and 2, both were disconnected during the bending test.

It is a figure explaining an example of the optical cable by this invention. It is a figure explaining Example 1 of the optical cable by this invention. It is a figure explaining Example 2 of the optical cable by this invention. It is a figure explaining Example 3 of the optical cable by this invention. It is a figure which shows the bending test method of an optical cable. It is a figure explaining a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 9 ... Optical connector, 10 ... Optical cable, 11 ... Optical fiber core wire, 12 ... Glass fiber, 13a, 13b ... Covering layer, 14 ... Colored layer, 15, 15a, 15b ... Tension member, 16 ... Cable jacket

Claims (7)

  An optical fiber with an optical fiber made mainly of quartz glass coated with a coating resin, a metal wire is not included inside, the outer dimension of the long side is 4 mm or less, and the cross section is rectangular or elliptical An optical cable characterized by being integrated with a jacket, having a total tensile tension of 50 N or more when the cable jacket is stretched by 1%, and having a connecting portion of an optical component attached to the cable jacket at a cable end.   2. The optical cable according to claim 1, wherein a coating resin having a Young's modulus of 0.1 MPa to 10 MPa is applied to the glass fiber of the optical fiber core wire in a state where there is no anti-shrink member in the cable. .   The optical cable according to claim 1 or 2, wherein the cable does not include a tension member, and the cable jacket is formed of a thermoplastic resin having a Young's modulus of 200 to 1500 MPa.   The high-strength fiber bundle is integrated on both sides of the optical fiber core wire by the cable jacket at a density of 50 N / cm to 900 N / cm for pulling the high-strength fiber bundle from the cable jacket. The optical cable according to claim 1.   On both sides of the optical fiber core, a rod-shaped wire material in which a high-strength fiber bundle is hardened with a matrix resin is arranged and integrated by the cable jacket, and the rod-shaped wire material is arranged in an arrangement direction with the optical fiber core wire. 2. The LAN optical cable according to claim 1, wherein the thickness in the orthogonal direction is a thickness that can withstand a predetermined bending test.   The bending test is characterized in that the total tensile tension of the cable jacket when the cable jacket is stretched 1% after bending 100,000 times under the condition of a radius of curvature of 9 mm and a right and left of 90 ° is 50 N or more. Item 6. The optical cable according to Item 5.   The optical cable according to any one of claims 4 to 6, wherein the high-strength fiber bundle has conductivity.

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