Optical fiber ribbon and method of manufacturing the same

Abstract

The optical fiber ribbon (10) has a plurality of resin-coated mono-coated optical fibers arranged in parallel, and a plurality of connecting portions (30) arranged between adjacent mono-coated optical fibers (20) to partially connect the adjacent mono-coated optical fibers. In a cross section perpendicular to the longitudinal direction of the mono-coated optical fiber in an area where no connecting portion is arranged, the ratio of the maximum length (D2) to the minimum length (D1) in the cross section of the mono-coated optical fiber is within a range of 1.02 to 1.14.

Description

[Technical Field]

[0001] The present invention relates to an optical fiber ribbon and a method for manufacturing the optical fiber ribbon. [Background technology]

[0002] In recent years, data traffic has increased dramatically due to the spread of IoT (Internet of Things), the full-scale commercialization of 5G, and autonomous driving of automobiles, and there is growing demand for the development and construction of high-speed, large-capacity optical fiber communication networks to support this.To economically realize the development and construction of high-speed, large-capacity optical fiber communication networks, it is important to accommodate as many mono-coated optical fibers (optical fibers) as possible within existing ducts. When accommodating many single-coated optical fibers in an existing duct, a rollable ribbon in which the single-coated optical fibers are intermittently connected is used from the viewpoint of workability in wiring installation work (see, for example, Patent Document 1).

[0003] Patent Document 1 describes an optical fiber ribbon having a plurality of optical fiber core wires arranged in parallel and an inter-core fiber connecting portion that intermittently connects adjacent optical fiber core wires. The method for manufacturing an optical fiber ribbon described in Patent Document 1 first arranges a plurality of optical fiber core wires in a row with a predetermined gap between them. Next, a tape-forming resin is applied so as to cover the entire periphery of the plurality of optical fiber core wires, and then the tape-forming resin between adjacent optical fiber core wires is partially removed before the tape-forming resin hardens. Finally, the tape-forming resin is hardened to manufacture the optical fiber ribbon. The optical fiber ribbon in the manufactured optical fiber ribbon is covered with a substantially uniform and thick tape-forming resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-108331 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the optical fiber ribbon described in Patent Document 1 contains a large amount of tape-forming resin, which makes it difficult to remove the resin during use.

[0006] An object of the present invention is to provide an optical fiber ribbon with high resin removability and a method for manufacturing the optical fiber ribbon. [Means for solving the problem]

[0007] In order to solve the above problem, according to one aspect of the present invention, a plurality of mono-coated optical fibers coated with resin, which are arranged in parallel; a plurality of connecting portions disposed between adjacent mono-coated optical fibers and partially connecting the adjacent mono-coated optical fibers; An optical fiber ribbon is provided in which, in a cross section perpendicular to the longitudinal direction of the mono-coated optical fiber in an area where the connecting portion is not arranged, the ratio of the maximum length to the minimum length in the cross section of the mono-coated optical fiber is within the range of 1.02 to 1.14.

[0008] According to another aspect of the present invention, arranging a plurality of mono-coated optical fibers in parallel; applying an uncured photocurable resin in a tape shape to the plurality of mono-coated optical fibers to form an uncured tape layer; a step of rotating a rotary blade or inserting and removing a needle with respect to the uncured tape layer to form a plurality of connection portions in which adjacent mono-coated optical fibers are partially connected and a separation portion in which adjacent mono-coated optical fibers are separated; and curing the uncured tape layer by irradiating the tape with light. There is provided a method for manufacturing an optical fiber ribbon, wherein in the step of forming the connecting portion and the separating portion, the distance between the rotary blade or needle and the mono-coated optical fiber is set within a range of 0 to 10 μm. [Effects of the Invention]

[0009] According to the present invention, an optical fiber ribbon with high resin removability and a method for manufacturing the optical fiber ribbon can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] 1A to 1C are diagrams showing an optical fiber ribbon according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram for explaining the shortest length and the longest length in the cross section of an optical fiber. [Figure 3] FIG. 3 is a flowchart of a method for manufacturing an optical fiber ribbon. [Figure 4] FIG. 4 is a diagram showing a schematic configuration of an optical fiber ribbon manufacturing apparatus. [Figure 5] 5A to 5C are side views showing a schematic configuration of the rotary blade of the separating die. [Figure 6] FIG. 6 is a side view schematically showing the state of rotation of the rotary blade. [Figure 7] FIG. 7 is a diagram illustrating a process of forming the connecting portion and the separating portion. [Figure 8] FIG. 8 is a diagram showing a schematic configuration of an optical fiber ribbon manufacturing apparatus according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an optical fiber ribbon and a method for manufacturing an optical fiber ribbon according to a preferred embodiment of the present invention will be described. In this specification, when a numerical range is indicated by "to", the lower limit and upper limit are included in the numerical range.

[0012] (1) Optical fiber ribbon configuration Fig. 1A is a schematic plan view of an optical fiber ribbon 10, Fig. 1B is a cross-sectional view taken along line AA in Fig. 1A, and Fig. 1C is a cross-sectional view taken along line BB in Fig. 1A. Fig. 2 is a schematic view for explaining the minimum length D1 and maximum length D2 in the cross section of an optical fiber 20.

[0013] The optical fiber ribbon 10 has a plurality of mono-coated optical fibers (hereinafter also simply referred to as "optical fibers") 20 and a plurality of connecting portions 30. The optical fiber ribbon 10 may have a plurality of spaced portions 41. As shown in FIGS. 1A to 1C, the optical fiber ribbon 10 of this embodiment has a plurality of mono-coated optical fibers 20, a plurality of connecting portions 30, and a plurality of spaced portions 41.

[0014] The optical fibers 20 are arranged in parallel. The number of optical fibers 20 is not particularly limited as long as it is two or more. The number of optical fibers 20 included in one optical fiber ribbon 10 is appropriately selected depending on the application of the optical fiber ribbon 10. The number of optical fibers 20 included in one optical fiber ribbon 10 is approximately 2 to 12. In this embodiment, twelve optical fibers 20 are arranged in parallel in one optical fiber ribbon 10.

[0015] 1B and 1C, the optical fiber 20 has an optical fiber strand 21, a primary coating layer 22, and a secondary coating layer 23. The optical fiber strand 21, the primary coating layer 22, and the secondary coating layer 23 can be the same as the optical fiber strand, first coating layer, and second coating layer of a known optical fiber. A colored layer may be further formed on the secondary coating layer 23 of the optical fiber 20. Preferably, the colors of the colored layers of the multiple optical fibers 20 within one optical fiber ribbon 10 are different from each other within the optical fiber ribbon 10. This allows the multiple optical fibers 20 to be distinguished from each other within one optical fiber ribbon 10.

[0016] In this embodiment, a tape layer 40 is further disposed around the plurality of optical fibers 20, and adjacent optical fibers 20 are intermittently connected by the tape layer 40. In this embodiment, the region where adjacent optical fibers 20 are partially connected is the connection portion 30, and the region where adjacent optical fibers 20 are partially separated is the separation portion 41.

[0017] The connecting portions 30 are disposed between all adjacent optical fibers 20, and partially connect the adjacent optical fibers 20. The separating portions 41 are disposed between all adjacent optical fibers 20, and partially separate the adjacent optical fibers 20. The arrangement of the connecting portions 30 and the separating portions 41 is not particularly limited. In the optical fiber ribbon 10 of this embodiment, the connecting portions 30 and the spaced portions 41 are alternately arranged in the longitudinal direction of the optical fiber ribbon 10. Furthermore, in the optical fiber ribbon 10, it is preferable that two or more spaced portions 41 are arranged between adjacent connecting portions 30 in the lateral direction of the optical fiber ribbon 10 (arrangement direction of the optical fibers 20). In the optical fiber ribbon 10 of this embodiment, two spaced portions 41 are arranged between adjacent connecting portions 30 in the lateral direction of the optical fiber ribbon 10 (arrangement direction of the optical fibers 20). This makes it possible to reduce the number of connecting portions 30, thereby making it possible to shorten the overall width of the optical fiber ribbon 10. The optical fiber ribbon 10 complies with IEC standards (IEC 60794-1-31:2018, JIS C 6838:2020) and Telcordia standard (Telcordia GR-20). In addition, in the short direction of the optical fiber ribbon 10, the spaced portions 41 are preferably arranged so that adjacent spaced portions 41 partially overlap each other.

[0018] 1A and 1B, the length L1 of the connecting portion 30 when the optical fiber ribbon 10 is viewed in plan is not particularly limited, but is, for example, in the range of 5 mm to 15 mm. The thickness T of the connecting portion 30 is also not particularly limited, but is, for example, in the range of 0.26 mm to 0.29 mm. When the length L1 and thickness T of the connecting portion 30 are within the above ranges, the strength of the connecting portion 30 is increased, and the connecting portion 30 is less likely to tear even when the optical fiber ribbon 10 is wound longitudinally or twisted as needed. On the other hand, the length L2 of the spaced apart portion 41 when the optical fiber ribbon 10 is viewed in plan is not particularly limited, but is, for example, in the range of 45 mm to 55 mm. When the length L2 of the spaced apart portion 41 is in this range, the optical fiber ribbon 10 can be easily wound or twisted along the longitudinal direction when the optical fiber ribbon 10 is housed in a cable. In this embodiment, the length L1 and thickness T of the connecting portion 30 and the length L2 of the spaced portion 41 are each the average values measured at any five points in the optical fiber ribbon 10.

[0019] As shown in FIGS. 1C and 2, in a cross section perpendicular to the longitudinal direction of the optical fiber 20 in a region where the coupling portion 30 is not disposed, the ratio (D2 / D1) of the longest length D2 to the shortest length D1 in the cross section is within a range of 1.02 to 1.14, and more preferably within a range of 1.07 to 1.14. In this embodiment, the shape of the cross section is not substantially circular but is substantially rectangular. The shortest length D1 in the cross section refers to the length of the shortest line segment among the line segments connecting any two points on the outer edge of the cross section and the center of gravity G of the cross section. In this embodiment, the shortest length D1 in the cross section is preferably the length in the direction along the arrangement direction of the multiple optical fibers 20. Furthermore, the longest length D2 in the cross section refers to the length of the longest line segment among the line segments connecting any two points on the outer edge of the cross section. In this embodiment, the line segment corresponding to the longest length D2 is inclined at approximately 45° with respect to the line segment corresponding to the shortest length D1. The line segment corresponding to the longest length D2 may or may not pass through the center of gravity in the cross section. In this embodiment, the line segment corresponding to the longest length D2 passes through the center of gravity G.

[0020] (2) Manufacturing method of optical fiber ribbon Next, a method for manufacturing the optical fiber ribbon 10 will be described. Fig. 3 is a flowchart of the optical fiber ribbon 10. Fig. 4 is a perspective view of a manufacturing apparatus 100 for manufacturing the optical fiber ribbon 10. Figs. 5A to 5C are side views showing a schematic configuration of the rotary blade of the separating die. Fig. 6 is a side view showing a schematic state of rotation of the rotary blade. Fig. 7 is a view for explaining the process of forming the connecting portion 30 and the separating portion 41.

[0021] As shown in FIG. 3, the manufacturing method of the optical fiber ribbon 10 of this embodiment includes a step of arranging the optical fibers in parallel (S110), a step of forming an uncured tape layer (S120), a step of forming a connecting portion 30 and a separating portion 41 (S130), and a step of curing the uncured tape layer (S140).

[0022] In the step (S110) of arranging the optical fibers in parallel, the above-described optical fibers 20 are arranged in parallel. The optical fibers 20 may be commercially available products or may be manufactured.

[0023] In the step (S120) of forming an uncured tape layer, the uncured tape layer 40 is formed using, for example, a manufacturing apparatus 100 shown in FIG. Specifically, while the optical fibers 20 are being transported in the transport direction A, an uncured photocurable resin is applied in a tape shape to the optical fibers 20 using a tape die 50 to form a tape layer 40 .

[0024] In the step (S130) of forming connecting portion 30 and separating portion 41, connecting portion 30 and separating portion 41 are formed using, for example, a manufacturing apparatus 100 shown in FIG. Specifically, rotary blades 62, 64, and 66 of the separation die 60 are rotated relative to the tape layer 40 to remove a portion of the tape layer 40 and form the connecting portion 30 and the separating portion 41. In the separation die 60, a plurality of rotary blades 62, 64, and 66 are provided facing the exit surface of the optical fiber 20. The rotation of each of the rotary blades 62, 64, and 66 is controlled by a motor so that they rotate in accordance with the transport of the optical fiber 20, and their rotation axes are all aligned. As shown in Fig. 5A, a notch 64a is formed in the central rotary blade 64, and as shown in Fig. 5B, notches 62a, 66a are also formed in the side rotary blades 62, 66. As shown in Fig. 5C, the notch 64a of the central rotary blade 64 and the notches 62a, 66a of the side rotary blades 62, 66 are out of phase with each other. In the process (S130) of forming the connecting portion 30 and the separating portion 41, as shown in FIG. 6, when each rotary blade 62, 64, 66 rotates in accordance with the transport of the optical fiber 20, the notch 64a of the central rotary blade 64 and the notch 62a, 66a of the rotary blades 62, 66 on both sides rotate while being out of phase with each other, and the separating portions 4 and connecting portions 3 are formed alternately. In addition, in Figures 4 to 6, three rotary blades 62, 64, and 66 are drawn for ease of explanation, but 11 such rotary blades are required to manufacture the optical fiber ribbon 10 shown in Figure 1.

[0025] As shown in Figure 7, the distance D between the rotary blades 62, 64, 66 and the optical fiber 20 is preferably in the range of 0 to 10 µm, more preferably in the range of 0 to 5 µm. By shortening the distance between the rotary blades 62, 64, 66 and the optical fiber 20 in this way, the tape layer 40 formed on the side of the optical fiber 20 can be made thinner. This improves resin removal, as described below, and satisfies the IEC standard and Telcordia standard. At this time, excess photocurable resin is sucked and collected by the resin suction device 70.

[0026] In the step (S140) of curing the uncured tape layer, the tape layer 40 is irradiated with light by the light irradiation device 80 to semi-cure the uncured tape layer, and finally, the semi-cured tape layer is completely cured by further irradiating with light by the light irradiation device 90. The cumulative irradiation doses of the upstream first light irradiation device 80 and the downstream second light irradiation device 90 are adjusted so that the cumulative irradiation dose of the first light irradiation device 80 is small and the cumulative irradiation dose of the second light irradiation device 90 is large. Because the distance D between the rotary blades 62, 64, 66 of the separating die 60 and the optical fiber 20 is within the range of 0 to 10 μm, the amount of photocurable resin applied to the optical fiber 20 is small, and the uncured photocurable resin does not wrap around the optical fiber 20 between the step (S130) of forming the connecting portion 30 and the separating portion 41 and the time when the uncured photocurable resin is cured. As a result, in a cross section perpendicular to the longitudinal direction of the optical fiber 20 in a region where the connecting portion 30 is not disposed, the ratio of the maximum length to the minimum length in the cross section is within the range of 1.02 to 1.14.

[0027] 8 may be used in place of the separating die 60 shown in Fig. 4 in the step (S130) of forming the connecting portion 30 and the separating portion 41, and needles 132, 134, 136 of the separating die 130 may be inserted into and removed from the tape layer 40 while controlling their elevation to remove part of the tape layer 40, thereby forming the connecting portion 30 and the separating portion 41. In this case as well, the distance D between the needles 132, 134, 136 and the optical fiber 20 is preferably in the range of 0 to 10 µm, and more preferably 0 to 5 µm.

[0028] (effect) As described above, according to the present invention, the ratio of the maximum length to the minimum length in the cross section of the optical fiber 20 is within a predetermined range, so that the tape layer 40 in the short direction of the optical fiber 20 in the area where the connecting portion 30 is not disposed is thin. This improves resin removal properties and makes it possible to obtain an optical fiber ribbon 10 that meets the width-related items of various international standards. [Example]

[0029] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited in any way by these examples, and the embodiments can be modified within the scope of the present invention.

[0030] (1) Sample preparation A single-coated optical fiber with an outer diameter of 250 μm was prepared by applying a primary coating made of a urethane acrylate photocurable resin and a secondary coating made of a urethane acrylate photocurable resin to a silica glass-based SM optical fiber with an outer diameter of 125 μm (a process for arranging optical fibers in parallel). Thereafter, using the manufacturing apparatus shown in FIG. 4, 12 single-coated optical fibers were aligned and coated with a urethane acrylate photo-curable resin to form a tape layer (a step of forming an uncured tape layer). The rotary blade was then rotated to form the connecting portion and the spaced portion (the step of forming the connecting portion and the spaced portion). Here, the length of the connecting portion was designed to be 10 mm, and the length of the spaced portion was designed to be 50 mm. The distance between the rotary blade and the single-coated optical fiber in the step of forming the connecting portion and the spaced portion was set as shown in Table 1. Thereafter, the uncured photocurable resin was cured by the upstream light irradiation device and the downstream light irradiation device to obtain an optical fiber ribbon (step of curing the uncured photocurable resin).

[0031] (2) Sample evaluation (2.1) Appearance evaluation of tape structure For each sample, a ruler was used to measure whether the connection and spacing between the optical fibers were manufactured according to the design values. The measurement results are shown in Table 1. In Table 1, the criteria for ◯, △, and × are as follows: 〇: Conforms to the design value (error is within 10%) △: There is an error of more than 10% from the design value ×: No separation portion is formed

[0032] (2.2) Evaluation of resin removability Bristle hardness as specified in JIS S 3061:1995 is 60N / cm 2 Using the brush described below, the optical fibers were separated from the optical fiber ribbon at room temperature (23°C). The separated optical fibers were then wiped with a commercially available resin removal tool (pulled while rubbing in one direction from the back to the front). This determined the number of wipes required to remove the tape layer from the surface of the optical fiber. This test was performed 32 times (n=32) for each sample, and the average number of wipes was calculated. The resin removability was evaluated based on the calculation results using the following criteria. ○: Wiping count is less than 5 times △: Number of wipings: 5 to less than 10 ×: Wiping count is 10 or more times

[0033] (2.3) Conformance Assessment Each sample was checked for compliance with the IEC standard (IEC 60794-1-31:2018) and the Telcordia standard (Telcordia GR-20). Specifically, for the IEC standard, the test was conducted to determine whether the optical fiber ribbon width was 3.4 mm or less, and for the Telcordia standard, the test was conducted to determine whether the optical fiber ribbon width was 3.27 mm or less. Compliance was evaluated according to the following criteria. ○: Compliant with standards ×: Not conforming to the standard

[0034] Table 1 shows the optical fiber ribbon number, the distance between the rotary blade and the single-coated optical fiber, the ratio of the longest length to the shortest length in the cross section perpendicular to the longitudinal direction of the optical fiber, and each evaluation result.

[0035] [Table 1]

[0036] As shown in Table 1, in Example Samples 1 to 3, in which the ratio of the maximum length to the minimum length in the cross section perpendicular to the longitudinal direction of the optical fiber was within the range of 1.02 to 1.14, the tape structure, resin removability, and standard conformance were all good. This is thought to be because there were thin portions of the tape layer coating the optical fiber. In particular, Example Samples 1 and 2, in which the ratio was within the range of 1.07 to 1.14, showed even better resin removability.

[0037] On the other hand, in Comparative Example Sample 4, where the ratio was not within the predetermined range, conformance to the standard was poor. This is thought to be due to the thick film thickness of the tape layer coating the optical fiber. In Comparative Examples Samples 5 and 6, the distance between the rotary blade and the single-coated optical fiber was excessively large (large clearance), and excess photocurable resin was integrated across the optical fibers (not separated), preventing the desired connection and separation sections from being formed. [Industrial Applicability]

[0038] The optical fiber ribbon according to the present invention is useful, for example, as an optical fiber used in a high-speed, large-capacity optical fiber communication network. [Explanation of symbols]

[0039] 10 Optical fiber ribbon 20 Single-coated optical fiber 21 Optical fiber strand 22 Primary coating layer 23 Secondary coating layer 30 Connecting part 40 tape layers 41 Separation part 50 Tape Dice 60, 130 Separate Dice 62, 64, 66 Rotary blade 70 Resin suction device 80 First light irradiation device 90 Second light irradiation device 100 Manufacturing equipment 132, 134, 136 Needles

Claims

1. a plurality of mono-coated optical fibers coated with resin, which are arranged in parallel; a plurality of connecting portions disposed between adjacent mono-coated optical fibers and partially connecting the adjacent mono-coated optical fibers; All of the plurality of mono-coated optical fibers are entirely coated with the resin that constitutes the connecting portion, a cross section of the mono-coated optical fiber in a region where the coupling portion is not disposed, the cross section being perpendicular to the longitudinal direction of the mono-coated optical fiber, is substantially rectangular; the ratio of the maximum length to the minimum length in the cross section of the mono-coated optical fiber is in the range of 1.02 to 1.14; Optical fiber ribbon core wire.

2. The optical fiber ribbon according to claim 1, The ratio of the maximum length to the minimum length in the cross section is in the range of 1.07 to 1.

14.

3. The optical fiber ribbon according to claim 1, The optical fiber ribbon has a shortest length in the cross section that is the length in a direction along the arrangement direction of the plurality of mono-coated optical fibers.

4. The optical fiber ribbon according to claim 1, The optical fiber cable further includes a spacing portion disposed between adjacent mono-coated optical fibers, the spacing portion spacing the adjacent mono-coated optical fibers apart, The number of the plurality of mono-coated optical fibers is 12, The optical fiber ribbon is configured such that two or more of the spaced apart portions are located between adjacent ones of the connecting portions in the arrangement direction of the single-coated optical fibers.

5. arranging a plurality of mono-coated optical fibers in parallel; applying an uncured photocurable resin in a tape shape to the plurality of mono-coated optical fibers to form an uncured tape layer; a step of rotating a rotary blade or inserting and removing a needle with respect to the uncured tape layer to form a plurality of connection portions in which adjacent mono-coated optical fibers are partially connected and a separation portion in which adjacent mono-coated optical fibers are separated; and curing the uncured tape layer by irradiating the tape with light. In the step of forming the connecting portion and the separating portion, the distance between the rotary blade or needle and the mono-coated optical fiber is set to a range of 0 to 10 μm, In the step of curing the uncured tape layer, the entire circumference of all of the plurality of mono-coated optical fibers is coated with the resin that constitutes the connecting portion, the shape of the cross section perpendicular to the longitudinal direction of the mono-coated optical fiber in the region where the connecting portion is not arranged is made to be approximately rectangular, and the ratio of the longest length to the shortest length in the cross section of the mono-coated optical fiber is set to be within a range of 1.02 to 1.

14. A manufacturing method for optical fiber ribbon.

6. 6. The method for producing an optical fiber ribbon according to claim 5, In the step of forming the connecting portion and the separating portion, the distance between the rotary blade or needle and the mono-coated optical fiber is set to a range of 0 to 5 μm, In the step of curing the uncured tape layer, the ratio of the maximum length to the minimum length in the cross section is set to a range of 1.07 to 1.

14. A manufacturing method for optical fiber ribbon.

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