JP2010164887A - Flat optical fiber cord - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat optical fiber cord in which coated optical fibers are less affected (damaged), by suppressing the bending of an optical fiber ribbon inside even if a pressure is actuated in the longitudinal direction. <P>SOLUTION: The flat optical fiber cord 1 is composed of one or a plurality of optical fiber ribbons 4 and a jacket 2 housing the optical fiber ribbons 4 and having a roughly rectangular cross section. In the inner side face of the jacket 2, there is provided a thick part 5 which is diagonally formed to be thicker than other parts. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flat optical fiber cord that accommodates a tape core wire therein.

  A flat optical fiber cord is a tape core in which a plurality of optical fibers are integrated with a resin and formed into a tape shape. The optical fiber cord is housed in an inner space formed of a jacket having a substantially rectangular cross section. The tape core is accommodated in the inner space of the jacket so that the major axis direction of the jacket and the width of the tape core (longitudinal direction of the cross section) substantially coincide.

  In order to prevent damage to the tape core due to the force applied from the outside of the jacket, a cushion material having a hardness lower than that of the sheath cannot be moved between the tape core on the longitudinal side surface of the jacket and the jacket. It has been proposed to be fixed to (see, for example, Patent Document 1).

JP 2003-295015 A

  However, as shown in FIG. 14, when pressure is applied to the flat optical fiber cord 21 in the major axis direction by being stepped on with a foot or the like, the jacket 22 is deformed, and the method described in Patent Document 1 is used. There is a risk that the internal tape core wire 24 will buckle. On the other hand, if the strength of the jacket is increased to prevent this, there is a problem that the laying property is deteriorated.

  An object of the present invention is to provide a flat optical fiber cord that suppresses bending of an internal tape core even when pressure is applied in a major axis direction, and can reduce the influence (damage) on the optical fiber core. Is to provide.

  In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention is a flat comprising one or a plurality of tape cores and an outer cover having a substantially rectangular cross section for accommodating the tape cores. In the type optical fiber cord, the inner side surface of the jacket is provided with a thick portion formed diagonally thicker than other portions.

  According to a second aspect of the present invention, in the flat optical fiber cord according to the first aspect of the invention, the tape core wire is disposed on the inner side of the outer cover in a state where the width direction is inclined with respect to the major axis direction of the outer cover. It is housed in a space.

  According to the present invention, even if pressure acts in the major axis direction, a flat optical fiber cord that suppresses bending of the internal tape core wire and can reduce the influence (damage) on the optical fiber core wire. Can be provided.

1 is a schematic cross-sectional view of a flat optical fiber cord 1 according to an embodiment of the present invention. It is a schematic sectional drawing of the flat type optical fiber cord 1 in the initial stage where the side pressure of the major axis direction was applied. It is a schematic sectional drawing of the flat type optical fiber cord 1 in the final stage where the side pressure of the major axis direction was applied. 1 is a schematic sectional view of a flat optical fiber cord 1 of Example 1. FIG. 3 is a schematic cross-sectional view of a flat optical fiber cord 1 of Example 2. FIG. 5 is a schematic cross-sectional view of a flat optical fiber cord 1 of Example 3. FIG. 6 is a schematic cross-sectional view of a flat optical fiber cord 1 of Example 4. FIG. 6 is a schematic cross-sectional view of a flat optical fiber cord 1 in Example 5. FIG. 6 is a schematic cross-sectional view of a flat optical fiber cord 1 of Example 6. FIG. 6 is a schematic cross-sectional view of a flat optical fiber cord 1 of Example 7. FIG. 3 is a schematic cross-sectional view of a flat optical fiber cord 11 of Comparative Example 1. FIG. 6 is a schematic cross-sectional view of a flat optical fiber cord 11 of Comparative Example 2. FIG. (A) is a top view which shows the method of a side pressure test, (b) is a B arrow view of (a), (c) is a C arrow view of (a). It is a schematic sectional drawing of the conventional flat type optical fiber cord 21 after the side pressure of a major axis direction is applied.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a cross-sectional view of a flat optical fiber cord 1 according to an embodiment of the present invention. The flat optical fiber cord 1 is generally composed of a jacket 2, a tensile strength fiber 3, and a tape core wire 4.

  For example, an aramid fiber, a PBO fiber, a carbon fiber, or the like can be used as the tensile fiber 3, and the tensile tension and external force (side pressure, etc.) required for the flat optical fiber cord 1 are appropriately adjusted according to the use environment. Is possible.

  The tape core 4 is formed into a tape shape by arranging a plurality of optical fiber cores 41 in which glass optical fibers are coated with an ultraviolet curable resin, and further coating with an ultraviolet curable resin 42. For example, twelve optical fiber cores coated with UV curable resin on a φ125 μm glass optical fiber are arranged and further coated with UV curable resin to form a tape core wire having a thickness of 0.3 mm and a width of 3.1 mm. it can. In FIG. 1, two tape core wires 4 are overlapped and stored in the inner space portion of the jacket 2 in a state where the tensile strength fibers 3 are arranged on both surfaces in the stacking direction.

  As the tape core 4, a two-core tape core or a four-core tape core formed by arranging two or four optical fiber cores with a diameter of 250 μm in a tape shape with an ultraviolet curable resin may be used.

  The outer cover 2 is made of an extrudable thermoplastic resin and is made of soft PVC (polyvinyl chloride), ethylene-ethyl acrylate (EEA), ethylene-vinyl acetate (EVA), or the like. Flame retardant resin containing inorganic flame retardant and flame retardant aid, polyolefin resin such as low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, etc. Things can be used. Furthermore, if necessary, these resins can be given a weather resistance prescription by blending carbon black, UV inhibitors, UV absorbers, etc., or colored prescription by blending color pigments. is there.

  As shown in FIG. 1, thick portions 5 are provided diagonally on the inner surface of the jacket 2. The portion of the outer cover 2 where the thick portion 5 is provided is designed to be thicker than the other portions of the outer cover 2 and has a swollen shape. When the outer cover 2 receives a side pressure in the major axis direction, the thick part 5 presses the tape core wire 4 in the minor axis direction and tilts it before the side pressure in the major axis direction acts on the tape core wire 4. . The thick portion 5 may be in direct contact with the tape core wire 4 to be tilted, or the thick wall portion 5 is in contact with the tensile strength fiber 3 and presses and tilts the tape core wire 4 through the tensile strength fiber 3. Also good.

  The size of the thick portion 5 may be appropriately designed according to the clearance between the tape core wire 4, the tensile strength fiber 3, and the outer sheath 2 that are housed in the flat optical fiber cord 1. When the cord is deformed by an external force (side pressure in the major axis direction), the tape core wire 4 is brought into contact with either the thick portion 5 of the jacket or the tensile strength fiber 3 or simultaneously, and a strong side pressure is applied to the tape core wire 4. What is necessary is just to design so that the tape core wire 4 may incline before being loaded.

  The shape of the thick portion 5 of the outer cover 2 can be made a desired shape by designing and processing the shape of the outer surface of the nipple used when the outer cover 2 is extruded.

  When such a thick portion 5 is provided, when the flat optical fiber cord 1 receives an external force (side pressure in the major axis direction), the strength is greatest in the major axis direction of the jacket 2 as shown in FIG. Deformation starts from a weak part (a part where the outer cover 2 is thin or a central part in the major axis direction). In the initial stage of the deformation, the thick portion 5 provided at the diagonal of the inner side surface of the jacket 2 presses the tensile strength fiber 3 and the tape core wire 4 to incline the tape core wire 4. For this reason, even when the tape core wire 4 is inclined following the deformation of the jacket 2 and is deformed to the maximum, the tape core wire 4 is prevented from being bent as shown in FIG. The influence (damage) on can be reduced.

  In FIG. 1, the tape core wire 4 is housed so that the arrangement direction of the optical fiber core wires is inclined with respect to the major axis direction of the jacket 2. In the cross section of the flat optical fiber cord 1, the center line of the minor axis of the outer sheath 2 is 0 °, the direction of rotation in the direction of the thick portion 5 around the center of the cross section of the flat optical fiber cord 1 is −, When the direction of rotation in the direction opposite to the meat part 5 is set to +, when the arrangement direction of the optical fiber cores is inclined by + 5 ° to + 45 ° with respect to the major axis direction of the jacket 2, a flat optical fiber The influence (damage) on the optical fiber core due to the external force (side pressure in the major axis direction) applied to the cord 1 becomes lighter, which is preferable.

  Further, only one tape core wire 4 may be provided alone or a plurality of tape core wires 4 may be provided, or different tape core wires 4 may be provided in combination. In any combination, the tape core wire 4 and the tensile fiber 3 are in contact with the thick portion 5 of the outer jacket 2 at the time of initial deformation with an external force (side pressure in the major axis direction) that the flat optical fiber cord 1 receives. What is necessary is just to design so that it may incline by pushing the tape core wire 4, before a strong side pressure is loaded to the tape core wire 4. FIG.

  Hereinafter, evaluation of the lateral pressure characteristics of the flat optical fiber cord 1 according to Examples and Comparative Examples will be described. In addition, the shape and dimension of the thick part 5 used below are one Example, and this invention is not limited to this.

  The flat optical fiber cord 1 was manufactured by changing the shape of the jacket 2 and the inclination angle with respect to the major axis direction of the tape core wire 4 incorporated therein. Five samples having a length of 1 m were cut out of the manufactured flat optical fiber cord 1 at intervals of 5 m in the longitudinal direction. A low-viscosity epoxy resin was injected using a syringe from a substantially central position of the cut 1 m sample. After the injected epoxy resin is cured, the sample is sliced, the cross section is enlarged 10 times using a universal projector, and the inclination angle of the tape core wire 4 is measured with a protractor. The dimensions of the outer jacket 2 (major axis length, minor axis length, and lengths a to c) were measured. Table 1 shows the average value of the measurement results of five cross sections cut out from the same flat optical fiber cord 1. Moreover, the cross-sectional shape of the flat optical fiber cord 1 reproduced from the average value of the measurement results is shown in FIGS.

  The major axis length, minor axis length, jacket thickness, and the meanings of the lengths a to c are as shown in FIG. Here, a is the distance between point A and point B in FIG. 4, b is the distance between point A and point D, and c is the distance between point A and point C. Further, point A is an intersection of an extension line L1 in the minor axis direction and an extension line L2 in the major axis direction of the inner side surface (excluding the thick portion 5; the same applies hereinafter) of the jacket 2 in FIG. Is the intersection of L1 and the surface of the thick portion 5, point C is the intersection of L2 and the surface of the thick portion 5, and point D is the bisector L3 of the corner BAC and the surface of the thick portion 5 Is the intersection of

(Side pressure test)
A lateral pressure test was conducted using the flat optical fiber cords of Examples 1 to 7 and Comparative Examples 1 and 2 in Table 1.
13 (a) is a plan view showing a method of a lateral pressure test, FIG. 13 (b) is a view taken in the direction of arrow B in FIG. 13 (a), and FIG. 13 (c) is a view in arrow C of FIG. 13 (a). FIG. As shown in FIG. 13 (b), with respect to the sample 3m of the flat optical fiber cord 1, the 2nd core wire and the 3rd core wire, 4th core wire and 5th core wire, 6th core wire and 7 at one end The core wire, the 8th core wire and the 9th core wire, the end surfaces of the 10th core wire and the 11th core wire are fused and loop-connected, and the LED 51 faces the end surface of the 1st core wire. I let you. Further, as shown in FIG. 13 (c), at the other end of the flat optical fiber cord 1, the first core wire, the second core wire, the third core wire and the fourth core wire, the fifth core wire and the sixth core The wires, No. 7 and No. 8, the No. 9 and No. 10, and the No. 11 and No. 12 cores were fused and loop connected. As a result, all the core wires from the first core wire to the 12th core wire were connected. Here, the first core wire to the 12th core wire are obtained by assigning numbers to the optical fiber core wires in the tape core wire in the order of arrangement, and the first core wire and the 12th core wire are in the tape core wire. It means the optical fiber core wires at both ends.

  Thereafter, as shown in FIG. 13 (a), the sample 3m of the flat optical fiber cord 1 is arranged in a U-shape with a bending diameter of 200 mm so that the major axis direction is the vertical direction, and the flat optical fiber cord is arranged. A 100 mm square lateral pressure plate 52 (iron plate) was placed on the bent portion of 1. Next, a lateral pressure was applied in the major axis direction of the flat optical fiber cord 1 by applying a load of up to 700 N at a speed of 1 mm / min to the lateral pressure plate 52.

[Confirm light transmission]
Then, the visible light of LED51 was entered from the 1st core wire side, and the influence on a tape core wire was confirmed by the visible light beam of LED51 by confirming visually from the 12th core wire end. In addition, as a criterion for evaluation, light transmission confirmation was visually performed on the 12th core terminal, and the light transmission was confirmed as pass (indicated by ○ in Table 2), and light transmission was not confirmed (No. 1 A part from the core wire to the 12th core wire was disconnected) and rejected (indicated as x in Table 2).

[Tape injury]
The outer cover of the flat optical fiber cord after the test was removed, and the damaged state of the tape core wire was confirmed. Visually check the tape core for damage, and accept that the surface of the tape core is intact (shown as ○ in Table 2), and the surface of the tape core is scratched (though not cracked but has damage) What was confirmed was determined to be acceptable (indicated as Δ in Table 2), and those in which cracks (including breakage of each core) were confirmed in the tape core were regarded as unacceptable (indicated as x in Table 2).

  The obtained results are shown in Table 2. In Table 2, the tape core wire on the side close to the upper thick portion (the tape core wire positioned on the upper side in the state of FIG. 3) is the upper layer, and the tape core wire on the side close to the lower thick portion ( The tape core wire located on the lower side in the state of FIG.

In Examples 1 to 7, light transmission was confirmed in both the upper layer and the lower layer. Moreover, although the damage | wound was confirmed on the surface of the tape core wire in the lower layer of Example 1 and the upper layer of Example 5, it was not damaged in other than that. It is considered that the provision of the thick portion 5 prevents the tape core wire 4 from being inclined following the deformation of the outer cover 2 and bending the tape core wire 4.
In addition, it turns out that what the tape core wire 4 inclines (Examples 2-4, 6-7) does not have a damage | wound, and is more preferable than what is not inclined (Examples 1 and 5).

  On the other hand, light transmission was not confirmed in Comparative Example 1, and light transmission was not confirmed even in the lower layer of Comparative Example 2. Moreover, in the comparative example 1, the crack was confirmed on the surface of the tape core wire 14, and the crack was confirmed on the surface of the tape core wire 14 in the lower layer of the comparative example 2.

  In addition, although the thick part 5 of the jacket 2 in the above embodiment has a diagonally symmetric structure and dimensions, it is not limited to diagonally symmetric. For example, one thick portion 5 on the diagonal may have the shape of the first embodiment, and the other thick portion 5 may have the shape of the fifth embodiment. Also, the dimensions need not be symmetrical. Moreover, the cross-sectional shape of the thick part 5 may be a wave shape.

1,11,21 Flat type optical fiber cord 2,12,22 Outer jacket 3,13,23 Tensile fiber 4,14,24 Tape core 5 Thick part

Claims (2)

One or more tape cores,
In a flat type optical fiber cord provided with a jacket having a substantially rectangular cross section for accommodating the tape core wire,
A flat optical fiber cord, wherein an inner side surface of the outer jacket is provided with a thick portion diagonally thicker than other portions.   2. The flat optical fiber according to claim 1, wherein the tape core wire is accommodated in an inner space portion of the jacket with a width direction inclined with respect to a major axis direction of the jacket. code.

Images