Rollable optical fiber ribbon

Abstract

The present invention relates to a rollable optical fiber ribbon having an optical fiber ribbon bonding structure, which prevents damage to bonding parts during a twist test under strengthened test conditions, and thus having improved durability against mechanical stress working on the rollable optical fiber ribbon during the manufacturing process of an optical cable and the installation work of the optical cable.

Description

Rollable fiber optic ribbon

[0001] The present invention relates to a rollable optical fiber ribbon. More specifically, the present invention relates to a rollable optical fiber ribbon having an optical fiber ribbon joint structure that prevents damage to the joint during a torsional tensile test under enhanced test conditions, thereby improving durability against mechanical stress applied to the rollable optical fiber ribbon during the optical cable manufacturing process and optical cable installation work.

[0002] To build a large-capacity optical communication network, an optical fiber ribbon made by splicing optical fibers in parallel can be used.

[0003] An optical fiber ribbon is a composite material made by joining multiple optical fibers in parallel using resin or the like. It is generally manufactured in the form of a strip, and these are sometimes laminated to form a ribbon laminate in the shape of a polygonal column.

[0004] These optical fiber ribbons are mainly used in large-capacity communication networks because of their advantage of being able to be connected in bulk by optical fiber ribbon at the connection point.

[0005] Furthermore, a rollable optical fiber ribbon is being introduced that can be rolled in the width direction into a cylindrical shape and laid to increase the utilization of the internal space of a conduit for constructing an optical communication network or the number of optical fiber cores that can be accommodated in an optical cable or optical unit.

[0006] Such a rollable optical fiber ribbon can have multiple intermittent joints formed by intermittently applying a joint resin along the length of the optical fiber between a pair of adjacent optical fibers for widthwise rolling, or by intermittently removing the resin between a pair of adjacent optical fibers after coating the entire optical fiber with the resin.

[0007] Meanwhile, rollable optical fiber ribbons can be subject to various mechanical stresses, such as tensile and torsional stress, during the optical cable manufacturing or installation process. In particular, unlike standard optical fiber ribbons, which cannot be rolled in the width direction, rollable optical fiber ribbons are more susceptible to mechanical stress due to the intermittent formation of multiple joints.

[0008] Accordingly, there is a great demand for a rollable optical fiber ribbon that has an optical fiber ribbon joint structure that prevents damage to the joint during a torsional tensile test under enhanced test conditions, thereby ensuring durability against mechanical stress applied to the rollable optical fiber ribbon during the optical cable manufacturing process and optical cable laying work.

[0009] The present invention aims to provide a rollable optical fiber ribbon having an optical fiber ribbon joint structure that prevents damage to the joint during a torsional tensile test under enhanced test conditions, thereby ensuring excellent durability against mechanical stress applied to the rollable optical fiber ribbon during the optical cable manufacturing process and optical cable laying work.

[0010] In order to solve the above problem, the present invention provides a rollable optical fiber ribbon capable of being rolled in the width direction, comprising: a plurality of optical fibers arranged in parallel in the length direction; and a plurality of joints arranged at a distance in the length direction of the optical fiber ribbon and joining a pair of adjacent optical fibers among the plurality of optical fibers, wherein at least one pair of optical fibers is arranged between the pair of joints adjacent in the width direction of the rollable optical fiber ribbon, and when a torsional tensile test is performed in which one end of a specimen of the rollable optical fiber ribbon is twisted in both directions at an angle of 360 degrees or more 40 times under the condition that a tensile load of 60 g or more per optical fiber is applied to a 300 mm-long specimen of the rollable optical fiber ribbon using a test device according to the standard TIA / EIA Std. 455-141, no cracks or separations occur in the plurality of joints.

[0011] Here, the joint can be formed by applying a bonding resin to the surface of the optical fiber and then UV curing the resin.

[0012] In this case, the joint can be formed by intermittently removing the resin between a pair of adjacent optical fibers after coating all optical fibers included in the rollable optical fiber ribbon.

[0013] And, the density of the joint may be 0.8 g / cm3 to 1.4 g / cm3, the tensile strength may be 2.0 MPa to 22 MPa, the elongation may be 40% to 210%, the elastic modulus may be 5 MPa to 90 MPa at 2.5% strain, and the viscosity may be 80 mPa·s to 800 mPa·s at 25°C.

[0014] In addition, the length of the joint portion may be 5 mm to 15 mm, the period of the joint portion may be 10 mm to 90 mm, and the length of the non-joined portion arranged between a pair of joint portions adjacent in the longitudinal direction of the rollable optical fiber ribbon may be 5 mm to 75 mm.

[0015] Here, the rollable optical fiber ribbon may have a non-bonded region in which all optical fibers are not bonded by the bonding portion in the width direction of 10 mm to 30 mm in length.

[0016] In this case, the longitudinal position of the optical fiber of each of the above joints can be arranged at the center of the longitudinal position of the adjacent joints.

[0017] And, the length of the joint portion is 5 mm to 18 mm, the period of the joint portion is 24 mm to 84 mm, the length of the non-joined portion arranged between a pair of adjacent joint portions in the longitudinal direction of the rollable optical fiber ribbon is 30 mm to 70 mm, and the length of the optical fiber longitudinal direction of the non-joined region where not all optical fibers are joined by the joint portion in the width direction of the optical fiber ribbon may be 3 mm to 15 mm.

[0018] Additionally, the longitudinal position of the optical fiber of each of the above joints can be arranged to be spaced apart from the longitudinal position of the adjacent joint by 1 / N.

[0019] Here, the torsional tensile test of the above-mentioned rollable optical fiber ribbon can be performed using a test device according to the standard TIA / EIA Std. 455-141.

[0020] In this case, in the torsional tensile test of the above-mentioned rollable optical fiber ribbon, the specimen of the above-mentioned rollable optical fiber ribbon can be subjected to a twisting motion of 40 or more times in both directions for 1 minute.

[0021] And, in the torsional tensile test of the above-mentioned rollable optical fiber ribbon, the specimen of the above-mentioned rollable optical fiber ribbon can be subjected to an action of being twisted alternately in different directions.

[0022] Additionally, in the torsional tensile test of the above-described rollable optical fiber ribbon, a tensile load in the range of 60 g to 110 g per optical fiber can be applied to a specimen of the above-described rollable optical fiber ribbon.

[0023] And, the width of the joint may be smaller than 1.6 times the outer diameter of the optical fiber.

[0024] According to the rollable optical fiber ribbon of the present invention, by strengthening the test conditions according to the standard TIA / EIA Std. 455-141 for the torsional tensile test of a general optical fiber ribbon and applying it to the torsional tensile test of a rollable optical fiber ribbon, it is possible to secure excellent durability of the rollable optical fiber ribbon against various mechanical stresses such as tensile force or torsional stress applied to the rollable optical fiber ribbon during the optical cable manufacturing process or optical cable laying work.

[0025] According to the rollable optical fiber ribbon according to the present invention, the arrangement of joints constituting the rollable optical fiber ribbon, the resin properties of the joints, or the size of the joints have an optimized optical fiber ribbon joint structure, so that cracking or separation of each joint constituting the rollable optical fiber ribbon can be effectively prevented during a torsional tensile test under enhanced test conditions.

[0026] FIG. 1 illustrates one embodiment of a rolled state of a rollable optical fiber ribbon according to the present invention.

[0027] FIG. 2 illustrates one embodiment of a torsional tensile test device for a rollable optical fiber ribbon according to the present invention.

[0028] FIG. 3 illustrates a plan view of one embodiment of a rollable optical fiber ribbon according to the present invention.

[0029] FIG. 4 illustrates a plan view of another embodiment of a rollable optical fiber ribbon according to the present invention.

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosure is thorough and complete, and to sufficiently convey the spirit of the invention to those skilled in the art. Like reference numbers designate like elements throughout the specification.

[0031] FIG. 1 illustrates one embodiment of a rolled state of a rollable optical fiber ribbon according to the present invention, and FIG. 3 illustrates a plan view of one embodiment of a rollable optical fiber ribbon according to the present invention.

[0032] A rollable optical fiber ribbon (100) according to the present invention can be configured by connecting a plurality of optical fibers (10) in parallel so that width-wise rolling is possible.

[0033] Referring to FIG. 1, when examining the cross-sectional structure of a plurality of optical fibers (10) constituting a rollable optical fiber ribbon (100) according to the present invention, each optical fiber (10) can be configured to include a core (11), a cladding layer (12), a coating layer (13), and a coloring layer (14).

[0034] The core (11) may be composed of glass or synthetic resin and transmits light. The clad layer (12) may be formed to surround the core (11).

[0035] The above cladding layer (12) uses glass or synthetic resin made of silica material having a relatively lower refractive index than the core (11), thereby causing total reflection of light passing through the center of the optical fiber (10), thereby transmitting a signal.

[0036] The above coating layer (13) may be formed by coating the surface of the clad layer (12) with a material including at least one of acrylate, polyimide, and carbon. The coating layer (13) is configured to directly surround the clad layer (12) and serves to absorb external impact transmitted to the clad layer (12). The coating layer (13) may be composed of multiple layers having different physical properties, such as modulus, in order to safely protect internal components.

[0037] The coloring layer (14) is applied to the surface of the coating layer (13) with a material containing a coloring agent such as a colored or colorless pigment to impart color to the optical fiber (10), thereby enabling identification of the optical fiber from other optical fibers through color.

[0038] Each optical fiber (10) constituting the above-mentioned rollable optical fiber ribbon (100) has a coloring layer (14) on the outermost layer so that the optical fibers (10) can be mutually identified.

[0039] Among the plurality of optical fibers (10) constituting the rollable optical fiber ribbon (100) according to the present invention, a pair of adjacent optical fibers (10) can be joined through a plurality of joints (20) intermittently spaced apart from each other along the length of the optical fiber.

[0040] In this way, the rollable optical fiber ribbon (100) according to the present invention is not formed integrally in the entire boundary area between a pair of adjacent optical fibers or on the surface of the rollable optical fiber ribbon (100) with the joints (20), but rather, as shown in FIG. 1, a plurality of joints (20) are intermittently formed in the longitudinal direction of the optical fiber between a pair of adjacent optical fibers (10), so that the rollable optical fiber ribbon (100) can be configured to be rolled in the width direction.

[0041] Meanwhile, a tensile force (T) may be continuously applied to the rollable optical fiber ribbon (100) during the manufacturing process of the optical cable or the installation work of the optical cable. The tensile force (T) refers to a resistance force generated in the cross section of the rollable optical fiber ribbon (100) due to a force that pulls the rollable optical fiber ribbon (100) in the longitudinal direction of the optical fiber.

[0042] In one embodiment, the optical cable may be configured to include a plurality of optical units including a plurality of rolled rollable optical fiber ribbons (100) formed by rolling the rollable optical fiber ribbon (100) in the width direction having the above-described configuration and a tube for accommodating the same, a cable core formed by assembling the plurality of optical units, and an outer jacket wrapping the cable core.

[0043] When manufacturing such an optical cable, a plurality of optical fibers (10) constituting a rollable optical fiber ribbon (100) are frequently subjected to various manufacturing processes, such as a tubing process, an assembly process, and a cabling process, in which the optical fibers (10) are pulled in the longitudinal direction of the optical fiber, so that a tensile force (T) can be applied to the rollable optical fiber ribbon (100).

[0044] In general, when manufacturing an optical cable, a tensile force (T) in the range of about 3g to 30g per optical fiber can be applied to the rollable optical fiber ribbon (100) provided inside the optical cable.

[0045] Here, the tubing process is a process of inserting a rollable optical fiber ribbon (100) into a tube made of a polymer material to form an optical unit, the assembling process is a process of assembling a plurality of optical units to form a cable core, and the cabling process is a process of extruding an outer jacket made of a polymer material such as polyethylene outside the cable core to cover a plurality of optical units.

[0046] Likewise, during the installation work of an optical cable, a plurality of optical fibers (10) constituting a rollable optical fiber ribbon (100) may be pulled in the longitudinal direction of the optical fiber by performing various operations, such as pneumatic installation work, installation work, and pulling work of the optical cable into the internal space of a conduit, so that a tensile force (T) may be applied to the rollable optical fiber ribbon (100).

[0047] In general, when laying an optical cable, a tensile force (T) of about 10g to 60g per optical fiber can be applied to the rollable optical fiber ribbon (100) provided inside the optical cable.

[0048] In this way, when damage occurs to the joint (20) constituting the rollable optical fiber ribbon (100) due to mechanical stress such as tensile force (T) applied to the rollable optical fiber ribbon (100) during the manufacturing process of the optical cable or the laying work of the optical cable, twisting or lifting of the optical fiber (10) may occur, so it is not easy to stably maintain the shape of the rollable optical fiber ribbon (100), that is, the joint state between the plurality of optical fibers (10) arranged in parallel in the rollable optical fiber ribbon (100), and as a result, the collective connection of the plurality of optical fibers included in the optical fiber ribbon may not be possible.

[0049] Therefore, in order to prevent damage to the joint (20) due to mechanical stress such as tensile force (T) applied to the rollable optical fiber ribbon (100) during the manufacturing process of the optical cable or the laying work of the optical cable, sufficient mechanical properties are required for each joint (20).

[0050] In order to sufficiently secure the physical properties of the joint (20), the rollable optical fiber ribbon (100) according to the present invention can be configured so that cracks or separation do not occur in the plurality of joints (20) constituting the rollable optical fiber ribbon specimen during a torsional tensile test under specific test conditions, such as tensile load, number of twists, and twist angle, which are preset.

[0051] Hereinafter, with reference to FIG. 2, a torsional tensile test device and test method for measuring the joint properties of a rollable optical fiber ribbon according to the present invention will be reviewed.

[0052] FIG. 2 illustrates one embodiment of a torsional tensile test device for a rollable optical fiber ribbon according to the present invention.

[0053] A torsional tensile test of a rollable optical fiber ribbon (100) according to the present invention can be performed using a torsional tensile test device (1000) illustrated in FIG. 2.

[0054] As illustrated in FIG. 2, a torsional tensile test device (1000) according to one embodiment may be configured to include a pair of support plates (1100a, 1100b) that support the lower and upper portions of the torsional tensile test device (1000), a plurality of support rods (1200) that vertically connect between the pair of support plates (1100a, 1100b), a load application plate (1300) that is supported by the plurality of support rods (1200) and can move up and down on the plurality of support rods (1200) and applies a tensile load to an optical fiber ribbon specimen, a pair of grip portions (1400a, 1400b) for holding and fixing both ends of the optical fiber ribbon specimen, and a torsional rotation portion (1500) for rotating one end of the optical fiber ribbon specimen fixed by the pair of grip portions (1400a, 1400b).

[0055] The above pair of support plates (1100a, 1100b) may be composed of a lower support plate (1100a) placed at the bottom of the torsional tensile test device (1000) and an upper support plate (1100b) placed at the top of the torsional tensile test device (1000).

[0056] A plurality of support rods (1200) may be provided between the lower support plate (1100a) and the upper support plate (1100b). The plurality of support rods (1200) may be composed of four support rods (1200) each positioned at the corner regions of the lower support plate (1100a) and the upper support plate (1100b).

[0057] The above four support rods (1200) are configured so that their lengths correspond to each other, but the length of the above four support rods (1200) can be configured to be longer than the length of the optical fiber ribbon specimen to be measured through the above torsional tensile test device (1000).

[0058] In addition, the four support rods (12000) may be arranged parallel to each other, and the four support rods (1200) may be made of a metal material such as stainless steel.

[0059] A load applying plate (1300) can be placed in a direction horizontal to the ground between the lower support plate (1100a) and the upper support plate (1100a), and the load applying plate (1300) can be fixed on the four support rods (1200).

[0060] The above load application plate (1300) may be a flat plate shape with four guide holes formed at each corner region of the load application plate (1300). The four support rods (1200) can pass through the four guide holes formed at each corner region of the load application plate (1300).

[0061] Accordingly, the load application plate (1300) is free to move up and down along the longitudinal axis of the four support rods (1200), but the load application plate (1300) may be restricted from moving in any direction other than the up and down direction on the four support rods (1200).

[0062] The above load application plate (1300) can apply a tensile load to an optical fiber ribbon specimen fixed between a pair of grip portions (1400a, 1400b). At this time, the weight of the load application plate (1300) can be adjusted according to the tensile load conditions required for the optical fiber ribbon specimen during a torsional tensile test.

[0063] The above pair of grip parts (1400a, 1400b) is composed of a lower grip part (1400a) installed on the upper surface of the load application plate (1300) and an upper grip part (1400b) installed on the lower surface of the upper support plate (1100b).

[0064] The lower grip portion (1400a) and the upper grip portion (1400b) can each use multiple fastening members to secure both ends of the optical fiber ribbon specimen.

[0065] In addition, the lower grip portion (1400a) and the upper grip portion (1400b) may each have a slot formed therein to prevent the optical fiber ribbon specimen from being damaged, and the slot formed in each grip portion (1400a, 1400b) may be filled with an elastic material to safely fix the optical fiber ribbon specimen therein without being deformed or damaged.

[0066] The above-mentioned torsional rotation part (1500) is installed on the upper support plate (1100b), and the above-mentioned torsional rotation part (1500) supports the upper grip part (1400b) and can be configured so that the upper grip part (1400b) can rotate in both directions with respect to the fixed upper support plate (1100b).

[0067] The above-mentioned torsional rotation part (1500) may be configured to include a mount member (1510) mounted on the upper portion of the upper support plate (1100b) and for fixing the position of the upper grip part (1400b); and a rotation member (1520) provided on the upper surface of the mount member (1510) and allowing torsional rotation of the upper grip part (1400b).

[0068] The above-mentioned rotary member (1520) may be configured to be rotatable by manual operation. In this case, the rotary member (1520) may be configured in the form of a handle so that it can be easily rotated by holding it by hand.

[0069] In addition, the above-mentioned rotary member (1520) may be configured to be rotationally driven by power. In this case, the above-mentioned rotary member (1520) may be provided with at least one driving motor that is rotationally driven according to preset condition variables such as a rotation range, a rotation direction, and a rotation cycle.

[0070] As the rotating member (1520) of the above-mentioned torsion rotating member (1500) rotates, one end of the optical fiber ribbon specimen fixed to the upper grip portion (1400b) rotates together, while the other end of the optical fiber ribbon specimen fixed to the lower grip portion (1400a) is fixed, so that when the rotating member (1520) rotates, a torsional moment can be applied to the optical fiber ribbon specimen fixed between a pair of the grip portions (1400a, 1400b).

[0071] Here, the torsional tensile test device (1000) illustrated in FIG. 2 may be a test device according to the standard TIA / EIA Std. 455-141. The standard TIA / EIA Std. 455-141 is a standardized test method for evaluating the mechanical properties of optical fiber ribbons by the Telecommunications Industry Association (TIA) and the Electronic Industries Alliance (EIA).

[0072] More specifically, the test method according to the standard TIA / EIA Std. 455-141 can evaluate how well the optical fiber ribbon specimen can withstand mechanical stress by periodically applying a torsion to the optical fiber ribbon specimen while applying a preset tensile load to the optical fiber ribbon specimen (100) with a length of 300 mm and checking whether the optical fibers (10) constituting the optical fiber ribbon specimen are separated or damaged. Through this, the durability of the optical fiber ribbon (100) can be evaluated.

[0073] Here, the test method according to the standard TIA / EIA Std. 455-141 is intended to evaluate the mechanical properties of a typical optical fiber ribbon. A typical optical fiber ribbon refers to an optical fiber ribbon having a joint structure in which the joint is continuously formed across the entire optical fiber boundary area or is integrally formed on the surface of the optical fiber ribbon, making widthwise rolling difficult or impossible.

[0074] According to the torsional tensile test method of a general optical fiber ribbon according to the standard TIA / EIA Std. 455-141, when a torsional tensile test is performed by twisting an optical fiber ribbon specimen 20 times at an angle of 180° in both directions under the condition of applying a tensile load of 500 g per optical fiber ribbon to a 300 mm long specimen of an optical fiber ribbon (100) using a torsional tensile test device (1000) as shown in FIG. 2, the mechanical properties of the optical fiber ribbon can be evaluated by checking for damage to the joint of the optical fiber ribbon specimen. Here, one rotation from the initial position to the original position and then to the original position, and then to the original position after rotating 180° in the opposite direction is defined as one rotation.

[0075] However, since the rollable optical fiber ribbon (100) according to the present invention has a structure capable of being rolled in the width direction, it is difficult to accurately evaluate the durability of the rollable optical fiber ribbon (100) when performing a torsion tensile test using a torsion tensile test device (1000) under test conditions according to the standard TIA / EIA Std. 455-141 based on a general optical fiber ribbon.

[0076] That is, since the rollable optical fiber ribbon (100) according to the present invention has a flexible joint structure compared to a general optical fiber ribbon, the rollable optical fiber ribbon (100) has relatively superior torsional properties compared to a general optical fiber ribbon, and thus the mechanical properties of the rollable optical fiber ribbon can be evaluated by strengthening the test conditions according to the standard TIA / EIA Std. 455-141.

[0077] Specifically, when a tensile load of 60 g or more per optical fiber is applied to a 300 mm long specimen of a rollable optical fiber ribbon (100) according to the present invention using a torsional tensile test device (1000) illustrated in FIG. 2, it is possible to check whether cracks or separations occur in the plurality of joints (20) constituting the optical fiber ribbon specimen during a torsional tensile test in which one end of the optical fiber ribbon specimen is twisted in both directions at an angle of 360 degrees or more 40 times under the condition that a tensile load of 60 g or more per optical fiber is applied.

[0078] Here, the length of the optical fiber ribbon (100) specimen of 300 mm is defined as the length (H) of the optical fiber ribbon specimen exposed and fixed between the pair of grip portions (1400a, 1400b).

[0079] This means that the mechanical stress is more severe than that in the torsion test of a general optical fiber ribbon by increasing the number of twists and the twist angle of the optical fiber ribbon specimen under the torsion tensile test conditions of a general optical fiber ribbon according to the standard TIA / EIA Std. 455-141.

[0080] If no cracks or separations occur in each joint (20) constituting the rollable optical fiber ribbon (100) after a torsional tensile test of the rollable optical fiber ribbon (100) using the torsional tensile test device (1000) illustrated in FIG. 2, it can be understood that the joint (20) sufficiently secures mechanical properties under the test conditions, and thus the durability of the rollable optical fiber ribbon (100) is improved.

[0081] Here, the crack in the joint (20) means that mechanical damage such as a crack or breakage has occurred in the material of the joint (20). The separation phenomenon of the joint (20) means that the joint (20) is not bonded to the surface of the optical fiber (10) but is separated from the surface of the optical fiber (10), or a crack occurs in the joint (20) itself, causing the adjacent optical fiber to be separated.

[0082] When a tensile load of 60 g or more per optical fiber is applied to a 300 mm long optical fiber ribbon specimen using a load application plate (1300) provided in the torsional tensile test apparatus (1000) illustrated in FIG. 2 during a torsional tensile test, it is possible to check whether cracks or separations occur in each joint (20) constituting the optical fiber ribbon (100). Preferably, a tensile load of 60 g to 110 g per optical fiber can be applied to a 300 mm long optical fiber ribbon specimen of the optical fiber ribbon (100).

[0083] For example, if the optical fiber ribbon specimen is composed of 12 optical fibers (10) connected in parallel, a tensile load of 720 g or more can be applied to the optical fiber ribbon specimen during a torsional tensile test.

[0084] In addition, during a torsional tensile test, the rotating member (1520) of the torsional rotation part (1500) of the torsional tensile test device (1000) can be manually operated or driven by a motor to rotate one end of the optical fiber ribbon specimen in both directions 40 or more times. Here, one rotation from the initial position to one direction by 360° and then returning to the original position, and then returning to the original position by 360° in the opposite direction is defined as one rotation.

[0085] Preferably, when a 300 mm long optical fiber ribbon specimen is twisted in both directions at least 40 times for 1 minute during a torsional tensile test, it is possible to check whether there is a crack or separation phenomenon in each joint (20) constituting the optical fiber ribbon specimen.

[0086] In addition, during a torsional tensile test, the torsional rotation part of the torsional tensile test device (1000) can be manually operated or driven to rotate to twist one end of the optical fiber ribbon specimen by more than 360 degrees.

[0087] Preferably, during a torsional tensile test, the optical fiber ribbon specimen is twisted alternately in different directions by a predetermined number of twists of 360 degrees or more, so that cracks or separation of the joint (20) can be checked.

[0088] That is, the rollable optical fiber ribbon (100) according to the present invention is subjected to a torsional tensile test using a test method according to the standard TIA / EIA Std. 455-141, but considering that the rollable optical fiber ribbon (100) according to the present invention has a structure capable of rolling in the width direction, unlike a general optical fiber ribbon, the test conditions according to the standard TIA / EIA Std. 455-141 are strengthened to perform the torsional tensile test, thereby sufficiently securing durability against mechanical stress occurring during the manufacturing process of the optical cable or the laying work of the optical cable.

[0089] In addition, the rollable optical fiber ribbon (100) according to the present invention can have an optical fiber ribbon joint structure optimized so that cracks or separation do not occur at the joint (20) during a torsional tensile test under the strengthened test conditions as described above. Hereinafter, the optical fiber ribbon joint structure according to the present invention will be examined in detail with reference to FIGS. 3 and 4.

[0090] As shown in FIGS. 3 and 4, the rollable optical fiber ribbon (100) according to the present invention can implement width-wise rolling of the rollable optical fiber ribbon (100) by intermittently arranging a plurality of joints (20) for joining adjacent pairs of optical fibers (10) along the optical fiber length direction in the boundary region of the pair of optical fibers (10) instead of forming joints (20) for joining adjacent pairs of optical fibers (10) in the entire boundary region of the optical fibers (10).

[0091] For example, the optical fiber ribbon (100) may have two optical fibers (10) arranged between two adjacent joints (20) in the width direction of the optical fiber ribbon as shown in FIG. 3, and four optical fibers (10) may be arranged between two adjacent joints (20) in the width direction of the optical fiber ribbon as shown in FIG. 4.

[0092] The above optical fiber ribbon (100) can be configured by joining a pair of optical fibers (10) arranged adjacently among a plurality of optical fibers (10) arranged in parallel through a plurality of joints (20) having a specific pattern along the length direction of the optical fiber ribbon.

[0093] For example, the length (a) of each of the joints (20) constituting the rollable optical fiber ribbon (100) having the exemplary structure illustrated in FIG. 3 may be 5 mm to 15 mm, the period (p) of the joints (20) may be 10 mm to 90 mm, and the length (c) of the non-joint portion may be 5 mm to 75 mm.

[0094] In this case, while allowing the width-wise rolling of the rollable optical fiber ribbon (100), the phenomenon of the optical fiber (10) being separated due to damage to the joint during the rolling process can be effectively prevented, and further, the number or volume of joints (20) required per unit area of ​​the rollable optical fiber ribbon (100) can be minimized, thereby reducing the manufacturing cost of the rollable optical fiber ribbon (100).

[0095] Additionally, the length (b) of the non-bonded region in which all optical fibers (10) are not bonded by the bonding portion (20) in the width direction of the rollable optical fiber ribbon (100) may be in the range of 10 mm to 30 mm.

[0096] When the length (b) of the above non-bonded region is configured in the range of 10 mm to 30 mm, the width-wise flexibility of the rollable optical fiber ribbon (100) can be optimized by using the same volume and the same number of bonding portions (20).

[0097] And, as illustrated in FIG. 3, when the rollable optical fiber ribbon (100) is composed of N optical fibers, the longitudinal position of the joint (20) that joins the nth optical fiber (10) (n is a natural number greater than or equal to 1) and the n+1th optical fiber (10) among the N optical fibers (10) can be arranged at the longitudinal position center of two consecutive joints (20) that join the n+1th optical fiber (10) and the n+2nd (n+2 is a natural number less than or equal to N)th optical fiber (10).

[0098] In this case, the rollable optical fiber ribbon (100) can be configured to have a uniform length (b) of the non-bonded region, and accordingly, uniform width-wise flexibility can be secured in the entire longitudinal position of the rollable optical fiber ribbon (100).

[0099] In the embodiment illustrated in FIG. 3, the rollable optical fiber ribbon (100) is composed of 12 pieces, and, for example, the positions of the plurality of spaced joints (20) for joining the 4th (n, n=4)th optical fiber (10(4)) and the 5th (n+1)th optical fiber (10) can be arranged at the center of the plurality of spaced joints (20) for joining the 5th (n+1)th optical fiber (10(5)) and the 6th (n+2)th optical fiber (10(6)), thereby minimizing the length (b) of the non-joined region.

[0100] On the other hand, if the longitudinal position of the optical fiber (10) of the joint (20) that joins the nth (n is a natural number greater than or equal to 1)th optical fiber (10) and the n+1th optical fiber (10) among N optical fibers (10) is the same as the longitudinal position of the joint (20) that joins the n+1th optical fiber (10) and the n+2nd (n+2 is a natural number less than or equal to N)th optical fiber (10), it is difficult to roll in the joint area where the joint (20) that joins the optical fibers (10) is arranged in the width direction, and the length (b) of the non-joined area becomes longer, making it difficult to roll the rollable optical fiber ribbon (100) in the width direction.

[0101] Therefore, it is preferable that the joints (20) that join a pair of optical fibers (10) are spaced apart from each other in the longitudinal direction, but the joints (20) that join adjacent pairs of optical fibers (10) are arranged so that they are staggered in the longitudinal direction.

[0102] In addition, the length (a) of each of the joints (20) constituting the rollable optical fiber ribbon (100) having the exemplary structure illustrated in FIG. 4 may be 5 mm to 18 mm, the period (p) of the joints (20) may be 24 mm to 84 mm, and the length (c) of the non-joint portion may be 30 mm to 75 mm.

[0103] In this case, while allowing the width-wise rolling of the rollable optical fiber ribbon (100), the phenomenon of the optical fiber (10) being separated due to damage to the joint during the rolling process can be effectively prevented, and further, the occurrence rate of defects in which adjacent joints (20) are unintentionally connected during the manufacturing of the rollable optical fiber ribbon (100) can be reduced.

[0104] In addition, the length (b) of the non-bonded region in which all optical fibers (10) are not bonded by the bonding portion (20) in the width direction of the rollable optical fiber ribbon (100) may be in the range of 3 mm to 15 mm. In this case, the width direction flexibility of the rollable optical fiber ribbon (100) can be optimized by using the same volume and the same number of bonding portions (20).

[0105] In the case of the optical fiber ribbon (100) having the exemplary structure illustrated in FIG. 4, the joint (20) that joins the nth optical fiber (10) (n is a natural number greater than or equal to 1) and the n+1th optical fiber (10), the joint (20) that joins the n+1th optical fiber (10) and the n+2nd optical fiber (10), the joint (20) that joins the n+2nd optical fiber (10) and the n+3rd optical fiber (10), and the joint (20) that joins the n+3rd optical fiber (10) and the n+4th optical fiber (10) may be in a diagonal or step-like pattern.

[0106] In this case, as illustrated in FIG. 4, the longitudinal position of the optical fiber ribbon of the joint (20) that joins the nth (n is a natural number greater than or equal to 1) optical fiber (10) and the n+1th optical fiber (10) among a plurality of optical fibers (10), the longitudinal position of the optical fiber ribbon of the joint (20) that joins the n+1th optical fiber (10) and the n+2nd optical fiber (10), the longitudinal position of the optical fiber ribbon of the joint (20) that joins the n+2nd optical fiber (10) and the n+3rd optical fiber (10), and the longitudinal position of the optical fiber ribbon of the joint (20) that joins the n+3rd optical fiber (10) and the n+4th optical fiber (10) may not all correspond.

[0107] For example, the rollable optical fiber ribbon (100) of the embodiment illustrated in FIG. 4 is composed of 12 optical fibers (10), and the longitudinal positions of the optical fiber ribbons for the joint (20) that joins the 1st (n, n=1)th optical fiber (10(1)) and the 2nd (n+1)th optical fiber (10(2)), the joint (20) that joins the 2nd (n+1)th optical fiber (10(2)) and the 3rd (n+2)th optical fiber (10(3)), the joint (20) that joins the 3rd (n+2)th optical fiber (10(3)) and the 4th (n+3)th optical fiber (10(4)), and the joint (20) that joins the 4th (n+3)th optical fiber (10(4)) and the 5th (n+4)th optical fiber (10(5)) may not all correspond.

[0108] Furthermore, among the plurality of optical fibers (10) constituting the optical fiber ribbon (100), the longitudinal position of the optical fiber ribbon of the joint (20) that joins the nth optical fiber (10) and the n+1th optical fiber (10), the longitudinal position of the optical fiber ribbon of the joint (20) that joins the n+1th optical fiber (10) and the n+2nd optical fiber (10), the longitudinal position of the optical fiber ribbon of the joint (20) that joins the n+3rd optical fiber (10) and the n+4th optical fiber (10), and the longitudinal position of the optical fiber ribbon of the joint (20) that joins the n+4th optical fiber (10) and the n+5th optical fiber (10) are configured to be spaced apart from each other by the same interval, so that the interval between adjacent joints (20) in the width direction of the optical fiber ribbon (100) can be made uniform, and accordingly, uniform width-direction flexibility can be secured in the entire longitudinal position of the optical fiber ribbon (100).

[0109] The optical fiber ribbon (100) illustrated in FIG. 4 can have the longitudinal positions of the optical fiber ribbon of four joints (20) periodically formed in the width direction of the optical fiber ribbon corresponding to each other.

[0110] Specifically, the longitudinal position of the optical fiber ribbon of the joint (20) that joins the nth (n is a natural number greater than or equal to 1) optical fiber (10) and the n+1th optical fiber (10) among a plurality of optical fibers (10) and the longitudinal position of the optical fiber ribbon of the joint (20) that joins the n+4th optical fiber (10) and the n+5th optical fiber (10) may correspond.

[0111] In the embodiment illustrated in FIG. 4, the longitudinal positions of the optical fiber ribbon with respect to the joint (20) that joins the 1st (n, n=1) optical fiber (10(1)) and the 2nd optical fiber (10(2)) among the 12 optical fibers (10) constituting the optical fiber ribbon (100), the joint (20) that joins the 5th optical fiber (10(2)) and the 6th optical fiber (10(3)), and the joint (20) that joins the 9th optical fiber (10(7)) and the 10th optical fiber (10(8)) are all configured to correspond to each other so that the optical fiber ribbon can be formed substantially in a straight line in the width direction of the optical fiber.

[0112] Next, the resin properties of the joint (20) constituting the rollable optical fiber ribbon (100) according to the present invention are examined.

[0113] The above joint (20) may be made of an ultraviolet (UV) curable resin, such as an epoxy resin, an acrylate resin, a polyurethane resin, etc., and may be formed by applying a UV curable resin to the surface of the optical fiber (10) and then UV curing it.

[0114] The above joint (20) allows the widthwise rolling of the rollable optical fiber ribbon (100) while allowing the joint (20) to be clearly separated when the joined optical fiber (10) is separated. In this case, the elongation of the cured or sintered resin may be 40% to 210%, preferably 85% to 190%, and the density may be 0.8 g / cm. 3 1.4 g / cm 3 , preferably 1.0 g / cm 3 1.2 g / cm 3 It could be.

[0115] In addition, in order to enable the widthwise rolling or rolling state maintenance of the rollable optical fiber ribbon (100), the elastic cross modulus (Secant Modulus) of the joint (20) may be 5 MPa to 90 MPa, preferably 5 MPa to 74 MPa, at 2.5% strain.

[0116] And, in order to form a plurality of joints (20) intermittently arranged along the length direction of the optical fiber (10) in this way, the resin or the like must be applied accurately and quickly, but must have appropriate flowability to prevent dropping before hardening or sintering. Therefore, the viscosity of the joints (20) may be in the range of 80 mPa·s to 800 mPa·s, preferably 90 mPa·s to 520 mPa·s, at 30°C.

[0117] In addition, since the plurality of joints (20) must have a sufficiently large stress to maintain excellent joint strength of the joints (10) even after hardening or sintering and prevent cracking or breakage of the joints (20) due to external impact, the tensile strength of the joints (20) may be 2.0 MPa to 22 MPa, preferably 5 MPa to 18 MPa.

[0118] Furthermore, the width (W) of the above joint (20) B ) is configured to be smaller than 1.6 times the outer diameter of the optical fiber (10) constituting the above-mentioned rollable optical fiber ribbon (100), thereby preventing a phenomenon in which a plurality of joints (20) adjacent in the width direction of the rollable optical fiber ribbon are unintentionally attached to each other during the formation of the joint (20) or a plurality of optical fibers (10) adjacent in the width direction of the rollable optical fiber ribbon are connected by each adhesive portion (20).

[0119] In this way, the rollable optical fiber ribbon (100) according to the present invention has an optical fiber ribbon joint structure in which the arrangement of the joints (20), the resin properties of the joints (20), the size of the joints (10), etc. are optimized, so that the rollable optical fiber ribbon (100) according to the present invention can prevent cracks or separation in each of the joints (20) constituting the rollable optical fiber ribbon (100) even under test conditions that are more stringent than the test conditions according to the standard TIA / EIA Std. 455-141 for general optical fiber ribbons during a torsional tensile test, that is, under test conditions in which a tensile load of 60 g or more per optical fiber is applied to a 300 mm long specimen of the optical fiber ribbon (100), and one end of the optical fiber ribbon specimen is twisted in both directions at an angle of 360 degrees or more 40 times.

[0120] While this specification has described preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the claims below. Therefore, any modified implementation that fundamentally includes the elements of the claims should be considered within the technical scope of the present invention.

Claims

1. In a rollable optical fiber ribbon capable of widthwise rolling, A plurality of optical fibers arranged in parallel in the longitudinal direction; and A plurality of joints are arranged longitudinally apart from each other in the optical fiber ribbon and comprise a plurality of joints for jointing adjacent pairs of optical fibers among the plurality of optical fibers, One or more pairs of optical fibers are arranged between a pair of adjacent joints in the width direction of the rollable optical fiber ribbon, A rollable optical fiber ribbon characterized in that no cracks or separations occur at multiple joints when a torsional tensile test is performed in which one end of a 300 mm long specimen of the rollable optical fiber ribbon is twisted in both directions at an angle of 360 degrees or more 40 times under conditions in which a tensile load of 60 g or more per optical fiber is applied to the specimen using a test device according to the standard TIA / EIA Std. 455-141.

2. In paragraph 1, A rollable optical fiber ribbon characterized in that the above joint is formed by applying a jointing resin to the surface of the optical fiber and then UV curing the resin.

3. In paragraph 1, A rollable optical fiber ribbon characterized in that the above joint is formed by intermittently removing resin between a pair of adjacent optical fibers after coating all optical fibers included in the rollable optical fiber ribbon.

4. In paragraph 1, A rollable optical fiber ribbon characterized in that the density of the joint is 0.8 g / cm3 to 1.4 g / cm3, the tensile strength is 2.0 MPa to 22 MPa, the elongation is 40% to 210%, the elastic modulus is 5 MPa to 90 MPa at 2.5% strain, and the viscosity is 80 mPa·s to 800 mPa·s at 25°C.

5. In paragraph 1, A rollable optical fiber ribbon, characterized in that the length of the joint is 5 mm to 15 mm, the period of the joint is 10 mm to 90 mm, and the length of the non-joined portion arranged between a pair of joints adjacent in the longitudinal direction of the rollable optical fiber ribbon is 5 mm to 75 mm.

6. In paragraph 5, The above rollable optical fiber ribbon is characterized in that the length of the non-bonded region in which all optical fibers are not bonded by the bonding portion in the width direction is 10 mm to 30 mm.

7. In paragraph 1, A rollable optical fiber ribbon, characterized in that the longitudinal position of each of the above joints is positioned at the center of the longitudinal position of the adjacent joints.

8. In paragraph 1, The length of the above joint is 5 mm to 18 mm, the period of the above joint is 24 mm to 84 mm, and the length of the non-joint portion arranged between a pair of adjacent joints in the longitudinal direction of the rollable optical fiber ribbon is 30 mm to 70 mm. The above optical fiber ribbon is a rollable optical fiber ribbon, characterized in that the length of the optical fiber in the non-bonded region in which all optical fibers are not bonded by the bonding portion in the width direction is 3 mm to 15 mm.

9. In paragraph 1, A rollable optical fiber ribbon, characterized in that the longitudinal position of each of the above-mentioned joints is spaced apart from the longitudinal position of an adjacent joint by 1 / N.

10. In paragraph 1, A rollable optical fiber ribbon, characterized in that the torsional tensile test of the above rollable optical fiber ribbon is performed using a testing device according to the standard TIA / EIA Std. 455-141.

11. In paragraph 1, A rollable optical fiber ribbon, characterized in that in a torsional tensile test of the above rollable optical fiber ribbon, a specimen of the rollable optical fiber ribbon is subjected to a twisting motion in both directions 40 times or more for 1 minute.

12. In paragraph 1, A rollable optical fiber ribbon, characterized in that in a torsional tensile test of the above rollable optical fiber ribbon, a specimen of the rollable optical fiber ribbon is subjected to an alternating twisting motion in different directions.

13. In paragraph 1, A rollable optical fiber ribbon, characterized in that a tensile load of 60 g to 110 g per optical fiber is applied to a specimen of the rollable optical fiber ribbon in a torsional tensile test of the rollable optical fiber ribbon.

14. In paragraph 1, A rollable optical fiber ribbon, characterized in that the width of the joint is smaller than 1.6 times the outer diameter of the optical fiber.

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