JP2003240979A - Sheet for optical fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To apply no stress to an optical fiber even if a tube for a loose tube coated optical fiber is extended or contracted due to temperature change or the like. <P>SOLUTION: In a sheet 11 for the optical fiber, the optical fiber 2 wired in sheets 4 is loosely covered with the tube 5 as far as the interior of each of sheet end edges and the tube 5 is drawn out to outside the sheet to serve for the single-core loose tube coated optical fiber 6. Where, the interior portion of the sheets in the tube 5 is covered with a cylindrical member 8 made of a resin, for example. As a result, a structure not restricting movement in the length direction of the tube is formed thanks to the upper and lower sheets 4. For example, when an optical connector 7 is installed on the extremity of the loose tube coated optical fiber 6, tube extension or contraction is absorbed in a manner that the interior of each of the sheets is slid in the length direction of the tube even if the tube 5 is extended or contracted due to the temperature change or the like. As a result, stress applied to the optical fiber 2 is prevented. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention covers an optical fiber laid in an optical fiber sheet loosely with a tube up to the inside of the edge of the sheet, and pulls it out of the sheet as a single-core loose tube optical fiber core wire. The present invention relates to an optical fiber sheet.

[0002]

2. Description of the Related Art A conventional optical fiber sheet 1 is shown in FIGS.
Indicates. In this optical fiber sheet 1, a tape-shaped multi-fiber optical fiber 3 in which a plurality of optical fibers 2 are formed into a tape is laid between upper and lower sheets 4 and 4, and each optical fiber 2
The tube 5 is loosely covered to the inside of the seat edge (to the inside of the seat), and each is branched as a single-core loose tube optical fiber core wire 6 and pulled out of the seat 4. An optical connector 7 is attached to the tip of the tube optical fiber core wire 6. Although the drawing length L of the optical connector 7 is shown to be short in FIG. 7, it is usually longer than the drawing (for example, 1 to 2 m). Pressure sensitive adhesives (adhesives) are applied to the upper and lower sheets 4, respectively, and when the upper and lower sheets 4 are bonded together, the ends of the tubes 5 are fixed to the sheet 4 side together with the optical fibers 2. As described above, since one end of the tube 5 is attached to the optical connector 7 and the other end is retained by the sheet 4, both ends of the tube 5 are fixed. As shown in the drawing, the inside portion of the tube 5 (the portion indicated by the length M ′ in FIG. 7) of the conventional optical fiber sheet 1 of this type directly contacts and is fixed to the upper and lower sheets 4 coated with the adhesive. Has been done.

[0003]

As described above, in the structure in which the end portion of the tube 5 of the loose tube optical fiber core wire 6 having the optical connector 7 attached to the tip is adhered and fixed in the sheet 4, both ends of the tube 5 are attached. When the tube 5 is expanded or contracted due to temperature change, for example, when the tube 5 is expanded or contracted due to temperature change when installed in an environment such as an engine room of an automobile, a trunk, or a room, stress of pulling or compressing the optical fiber 2 due to the expansion or contraction There is a drawback that it costs. In addition,
Since the linear expansion coefficient of the resin of the tube 5 is larger than the linear expansion coefficient of the glass of the optical fiber 2, the expansion and contraction of the tube 5 greatly affects the temperature change as described above.

The present invention has been made in order to eliminate the above-mentioned conventional drawbacks. Even if the tube of the loose tube optical fiber core wire expands or contracts due to environmental changes such as temperature changes, the optical fiber may be stressed. The purpose is to provide a fiber optic sheet that does not.

[0005]

According to a first aspect of the present invention, an optical fiber wired in a sheet is loosely covered with a tube up to the inner side of the edge of the sheet to form a single-core loose tube optical fiber core wire outside the sheet. In the drawn optical fiber sheet, the inner portion of the tube has a length-direction unconstrained structure in which movements in the tube length direction are not restricted by upper and lower sheets.

According to a second aspect of the present invention, each of the tape-shaped multi-fiber optical fibers laid in the sheet is loosely covered with a tube up to the inside of the edge of the sheet, and each is a single-core loose tube optical fiber. In the optical fiber sheet that is branched as a core wire and drawn out of the sheet, the inside portion of each tube has a length-unconstrained structure in which movements in the tube length direction are not restricted by upper and lower sheets.

A third aspect of the present invention is that the lengthwise unconstrained structure of the optical fiber sheet according to the first or second aspect is obtained by covering at least the inner portion of the tube with a resin cylindrical member having an inner diameter that does not adhere to the outer peripheral surface of the tube. It is characterized by being configured.

According to a fourth aspect of the present invention, a lengthwise unconstrained structure of the optical fiber sheet according to the first or second aspect is a pair of halves, which is obtained by dividing a tube into at least an inner portion of a sheet with a resin cylindrical member halved. It is characterized in that it is constructed by covering one piece from above and below.

A fifth aspect of the present invention is the optical fiber sheet according to the first or second aspect, wherein an optical connector is attached to the tip of the loose tube optical fiber core wire.

According to a sixth aspect of the present invention, in the optical fiber sheet of the second aspect, the loose tube optical fiber core wires are branched in a two-dimensional array.

[0011]

1 is a partially cutaway plan view of an optical fiber sheet 11 according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view taken along the line AA of FIG. 1, and FIG. 2B is an enlarged cross-sectional view taken along the line BB, and (B) is an enlarged cross-sectional view taken along the line CC of FIG. 2 and 3A are sectional views showing the upper sheet without cutting out. In the optical fiber sheet 11 of the embodiment, a tape-shaped multi-core optical fiber 3 formed by tape-forming a plurality of optical fibers 2 is laid between the upper and lower sheets 4 and 4, and each optical fiber 2 is provided with a sheet edge inside. Up to the inside of the sheet (to the inside of the sheet), the tube 5 is loosely covered, and each is branched as a single-core loose-tube optical fiber core wire 6 and pulled out of the sheet 4. Each branched loose-tube optical fiber core wire An optical connector 7 is attached to the tip of 6. Although the drawing length L of the optical connector 7 is shown to be short in FIG. 1, it is usually longer than the drawing (for example, 1 to 2 m).
etc). In the above description, for example, covering the optical fiber 2 with the tube 5 "loosely" means that the optical fiber 2 is inserted into the inner surface of the tube 5 with a gap and without being in close contact with the inner surface.

According to the present invention, at least the inner portion of the tube 5 (the portion indicated by the length M in FIGS. 1 and 2) is moved in the tube length direction by the upper and lower sheets 4 (movement in the left and right directions in FIGS. 1 and 2). ) Is an unconstrained structure in the length direction. In this embodiment, as a length-direction unrestrained structure, a resin cylindrical member having an inner diameter (that is, a gap with respect to the outer peripheral surface of the tube 5) that does not adhere to the outer peripheral surface of the tube in the sheet inner portion M of the tube 5. 8 is covered with an appropriate margin length (S dimension in FIG. 2). The material of the cylindrical member 8 is not particularly limited, but nylon resin or the like can be used, for example. The upper and lower sheets 4 each have a rubber-based or acrylic-based room temperature pressure-sensitive adhesive (adhesive) on one side.
Is applied, and when the upper and lower sheets 4 are attached,
A cylindrical member 8 is bonded and fixed to each optical fiber 2 by upper and lower sheets 4. However, the inner part M of the tube 5
Is inserted in the cylindrical member 8 with a gap,
Since it is not in direct contact with the sheet 4 to which the adhesive is applied, the upper and lower sheets 4 do not restrain the movement in the length direction. The cylindrical member 8 adhered and fixed by the upper and lower sheets 4 is normally crushed into a flat shape.

Explaining the material of the upper and lower optical fiber sheets 11, it is a flexible resin sheet, and its material and thickness are required workability, abrasion resistance, waist strength (bending rigidity). , Young's modulus is selected in accordance with the tensile strength, and is appropriately selected. For example, polyimide, polyethylene terephthalate, low density or high density polyethylene, polypropylene, polyester, nylon 6, nylon 66, ethylene-tetrafluoroethylene copolymer, poly 4-methylpentene, polyvinylidene chloride, plasticized polyvinyl chloride, Polyether ester copolymer,
Films of ethylene-vinyl acetate copolymer, soft polyurethane, etc. are used. As the material of the tube 5,
Various materials can be used from the viewpoints of wear resistance, flame resistance, smoothness, etc., for example, nylon resin or the like can be used. Further, the optical fiber 2 is an optical fiber element wire obtained by coating a bare fiber, or an optical fiber core wire obtained by further coating.

In the above optical fiber sheet 11, the optical fiber 2 and the tube 5 are fixed to the optical connector 7 at the tip of the loose tube optical fiber core wire 6 extending from the edge of the sheet 4. On the other hand, since the linear expansion coefficient of the resin tube 5 is larger than that of the glass optical fiber 2 and the amount of expansion and contraction of the tube 5 due to temperature change is large,
When the temperature changes, the tube 5 also expands and contracts with respect to the optical fiber 2. In this way, when the tube 5 expands and contracts due to the temperature change, since the tip of the tube 5 is fixed to the optical connector 7, the expansion and contraction of the tube 5 is wrinkled toward the sheet 4 side. Since the inner portion M is inserted into the cylindrical member 8 with a gap and is not restrained from moving in the lengthwise direction, the expansion and contraction of the tube 5 is absorbed in the form in which the sheet inner portion M of the tube 5 slides in the lengthwise direction. There is no tensile or compressive stress on the. Therefore, there is no problem that the optical fiber 2 is pulled or compressed by the expansion and contraction of the tube 5. The length N (see FIG. 2) of the cylindrical member 8 should be long enough so that the tube 5 does not enter further from the inner end of the cylindrical member 8 even when the tube 5 is stretched to the maximum due to temperature rise or the like. Keep it. Further, the length M of the in-sheet portion of the tube 5 may be set longer than in the conventional case so that the tube 5 does not come out from the edge of the sheet even when the tube 5 is maximally contracted due to temperature decrease or when the tube 5 is pulled. As a result, no matter how the tube 5 expands or contracts due to temperature changes or the like, the sheet inner portion M of the tube 5 is kept inserted into the cylindrical member 8, and the tube 5
Even if you pull the sheet, it will not come out from the edge of the sheet.

In the above-described embodiment, the tube 5 is covered with the resin cylindrical member 8 with an appropriate margin as an unconstrained structure in the longitudinal direction of the in-seat portion of the tube 5, but FIG. 4, a pair of half-split pieces 18 obtained by splitting a resin cylindrical member in half may be arranged above and below the inner seat portion of the tube 5. The upper and lower halves 18 are adhered and fixed to the upper and lower sheets 4, respectively, and the sheet inner portion of the tube 5 is located between the upper and lower halves 18 and is not restrained from moving in the length direction. It is also possible to attach a thin film to the inner surface of the sheet 4 in the area of the inner portion of the tube 5 to cover the adhesive on the inner surface of the sheet 4, thereby preventing the sheet 4 from adhesively fixing the tube 5. To be Further, it may be considered that the adhesive is not applied to the inner surface of the sheet 4 in the area of the inner portion of the tube 5 of the sheet. In short, it suffices that the inner portion of the tube 5 is not constrained from moving in the longitudinal direction by the upper and lower sheets 4.

In each of the above-mentioned embodiments, each optical fiber 2 of the tape-shaped multi-core optical fiber 3 is branched as a loose tube optical fiber core wire 6 arranged side by side, but as shown in FIG. It is also possible to apply when branching with. That is, for example, the tape-shaped multi-fiber optical fiber 3'of, for example, 12 cores shown in FIG. 5B corresponding to the CC sectional view of FIG. ), In the case of stacking and branching in three stages, for example, a cylindrical member 38 is put on the inner part of the sheet of the whole tube 5 stacked in three stages to cover the inner part of the seat of the whole tube 5 in three stages. Unconstrained structure in the length direction.

In each of the above embodiments, each tube 5
The inner portions of the sheet may be simply aligned, but may be integrated by adhering adjacent portions with an adhesive. In this case, since the inner portion of the sheet of each tube 5 is bonded by an adhesive, it is not suitable when different expansion and contraction amounts occur for each tube 5, but it is usually not suitable for environmental changes such as temperature changes. Since each tube 5 expands and contracts evenly, the optical fiber 2
It is usually effective as a structure that does not stress the user.

The present invention is applicable not only to the case of branching a multi-core optical fiber but also to the case of a single-core optical fiber.
That is, FIG. 6B is a view corresponding to the CC sectional view of FIG. 1, and FIG. 6A is a view corresponding to the BB sectional view of FIG. A single optical fiber 2 wired inside is covered with a tube 5 to the inside of the sheet edge,
When the single-core loose tube optical fiber core wire 6 is pulled out of the seat, the seat inner portion of the tube 5 is covered with, for example, a cylindrical member 38, so that the seat inner portion of the tube 5 has a longitudinal unconstrained structure.

Further, the present invention is particularly effective when the optical connector 7 is attached to the tip of the loose tube optical fiber core wire 6, but the connection destination does not necessarily have to be the optical connector.

[0020]

According to the present invention, in an optical fiber sheet in which an optical fiber wired in a sheet is pulled out of the sheet as a loose tube optical fiber core wire, the inner portion of the tube is formed by upper and lower sheets. The length-unconstrained structure that does not constrain the movement in the length direction allows the tube to expand and contract in the longitudinal direction due to environmental changes such as temperature changes when an optical connector is attached to the end of the loose-tube optical fiber core. Even so, the expansion and contraction of the tube is absorbed in the form that the inner portion of the tube slides in the length direction, and it is possible to prevent the optical fiber from being subjected to tensile or compressive stress.

The present invention is suitable for branching a multi-core optical fiber laid in a sheet as a single core loose-tube optical fiber core.

According to the third aspect of the present invention, at least the inner portion of the sheet is covered with the resin cylindrical member having the inner diameter that does not adhere to the outer peripheral surface of the tube, so that the longitudinal unconstrained structure can be easily obtained. . Further, as in claim 4,
A lengthwise unconstrained structure can also be easily obtained by a structure in which at least the inside portion of the tube is covered with a pair of half-split pieces formed by splitting a resin cylindrical member in half from above and below.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view of an optical fiber sheet according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line AA of FIG.

3A is a sectional view taken along line BB of FIG. 1, and FIG. 3B is a sectional view taken along line CC of FIG.

FIG. 4 shows another embodiment of the optical fiber sheet of the present invention, and is a view corresponding to FIG.

FIG. 5 shows still another embodiment of the optical fiber sheet of the present invention, in which (a) corresponds to FIG. 3 (a),
(B) is a figure corresponding to FIG. 3 (b).

FIG. 6 shows still another embodiment of the optical fiber sheet of the present invention, in which (a) corresponds to FIG. 3 (a),
(B) is a figure corresponding to FIG. 3 (b).

FIG. 7 is a partially cutaway plan view showing a conventional optical fiber sheet.

8 is a cross-sectional view taken along the line DD of FIG.

[Explanation of symbols]

2 optical fiber 3 Tape-shaped multi-fiber optical fiber 4 seats 5 tubes (loose tubes) 6 Loose tube optical fiber core 7 Optical connector 8, 28, 38 Cylindrical member 11 Optical fiber sheet 18 halves Sheet inside part of M tube

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuhiro Takizawa             1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Sa Co., Ltd.             Inside the warehouse F-term (reference) 2H038 CA52                 2H046 AA02 AA05 AA62 AC21 AD22

Claims (6)

[Claims] 1. An optical fiber sheet in which a tube is loosely covered up to the inside of a sheet end edge with an optical fiber laid in a sheet and is drawn out of the sheet as a single-core loose tube optical fiber core wire. An optical fiber sheet, wherein an inner portion of the sheet has a length-direction unrestrained structure in which movements in the tube length direction are not restricted by upper and lower sheets. 2. Loosely covering each optical fiber of the tape-shaped multi-core optical fiber laid in the sheet with a tube up to the inside of the edge of the sheet, and branching each as a single-core loose tube optical fiber core. In the optical fiber sheet drawn out of the sheet, the inside portion of each of the tubes has a length-direction unrestrained structure in which movements in the tube length direction are not restricted by upper and lower sheets. 3. The length-direction unrestrained structure is constructed by covering at least an inner portion of the tube of the tube with a resin cylindrical member having an inner diameter that does not adhere to the outer peripheral surface of the tube. 2. The optical fiber sheet according to 2. 4. The length-direction unrestrained structure is characterized in that at least the inner portion of the sheet of the tube is covered with a pair of half-split pieces formed by splitting a resin cylindrical member in half from above and below. The optical fiber sheet according to claim 1 or 2. 5. The optical fiber sheet according to claim 1, wherein an optical connector is attached to the tip of the loose tube optical fiber core wire. 6. The optical fiber sheet according to claim 2, wherein the loose tube optical fiber core wire is branched in a two-dimensional array.