Method for manufacturing optical fiber ribbon and device for manufacturing optical fiber ribbon

Abstract

Provided is a method for manufacturing an optical fiber ribbon in which a plurality of single-core coated optical fibers are partially joined, the method for manufacturing an optical fiber ribbon including a step for heating the plurality of single-core coated optical fibers before coating the plurality of single-core coated optical fibers with an uncured resin.

Description

Method for manufacturing optical fiber ribbon core wire and manufacturing apparatus for optical fiber ribbon core wire

[0001] The present invention relates to a method for manufacturing an optical fiber ribbon core wire and a manufacturing apparatus for an optical fiber ribbon core wire.

[0002] In recent years, due to the spread of IoT (Internet of Things), the full-scale commercialization of 5G, and the autonomous driving of automobiles, data traffic has increased exponentially, and the demand for the construction and establishment of high-speed and large-capacity optical fiber communication networks to support it has been increasing. In order to economically realize the construction and establishment of a high-speed and large-capacity optical fiber communication network, it is important to accommodate more single-core coated optical fibers (optical fibers) in existing ducts. When performing wiring installation work to accommodate such a large number of single-core coated optical fibers in an existing duct, in order to improve workability, an optical fiber ribbon core wire (rollable ribbon) in which single-core coated optical fibers are intermittently connected is often used. In such an optical fiber ribbon core wire, between adjacent optical fibers, resin connecting portions for connecting them and spaced portions that are spaces for separating them are alternately arranged.

[0003] Patent Document 1 discloses a method for manufacturing an optical fiber ribbon core wire and a manufacturing apparatus therefor. In the manufacturing method and manufacturing apparatus described in Patent Document 1, after applying an uncured UV-curable resin to a plurality of optical fibers arranged in parallel, it is cured. When applying the uncured UV-curable resin, the arrangement of the UV-curable resin is controlled so that the UV-curable resin is intermittently present between adjacent optical fibers by rotating a disk having cutouts between adjacent optical fibers. By curing the UV-curable resin arranged intermittently in this way, a plurality of alternately arranged connecting portions and a plurality of spaced portions are formed.

[0004] Japanese Unexamined Patent Application Publication No. 2010-33010

[0005] However, the inventors have found that with conventional optical fiber ribbon core manufacturing methods and apparatus as described in Patent Document 1, when attempting to manufacture high-density optical fiber ribbon cores by arranging small-diameter optical fibers at a narrow pitch, adjacent optical fibers come into contact with each other after the uncured resin is applied, making it impossible to properly form the separated portions.

[0006] The object of the present invention is to provide a method for manufacturing optical fiber ribbon cores and an apparatus for manufacturing optical fiber ribbon cores that can appropriately form connecting portions and separated portions even when multiple small-diameter optical fibers are arranged at a narrow pitch.

[0007] To solve the above problems, according to one aspect of the present invention, a method for manufacturing an optical fiber ribbon core in which a plurality of single-core coated optical fibers are partially connected is provided, comprising the step of heating the plurality of single-core coated optical fibers before coating them with an uncured resin.

[0008] According to another aspect of the present invention, there is a manufacturing apparatus for optical fiber ribbon cores in which a plurality of single-core coated optical fibers are partially connected, comprising: a heating unit for heating the plurality of single-core coated optical fibers; a coating unit for coating the heated plurality of single-core coated optical fibers with an uncured resin; a removal unit for partially removing the uncured resin between adjacent single-core coated optical fibers among the plurality of single-core coated optical fibers coated with the uncured resin; and a curing unit for curing the uncured resin remaining on the plurality of single-core coated optical fibers.

[0009] According to the present invention, it is possible to provide a method for manufacturing optical fiber ribbon cores and an apparatus for manufacturing optical fiber ribbon cores that can appropriately form connecting portions and separated portions even when multiple small-diameter optical fibers are arranged at a narrow pitch.

[0010] Figures 1A to 1C are schematic diagrams showing optical fiber ribbon cores. Figure 2 is a diagram showing the schematic configuration of an optical fiber ribbon core manufacturing apparatus. Figures 3A and 3B are schematic diagrams showing the configuration of the removal section. Figures 4A and 4B are schematic diagrams showing the configuration of the rotating blade. Figure 5 is a flowchart of the optical fiber ribbon core manufacturing method.

[0011] The following describes a preferred embodiment of the present invention: a method for manufacturing optical fiber ribbon cores and an apparatus for manufacturing optical fiber ribbon cores. In this specification, with respect to the notation "~" indicating a numerical range, the lower limit and upper limit are included within that numerical range.

[0012] First, we will describe the optical fiber ribbon core that is the subject of manufacturing, and then we will describe the manufacturing apparatus and manufacturing method for the optical fiber ribbon core. In the following description, the direction in which the optical fibers are arranged in parallel will be referred to as the first direction (D1), the length direction of the optical fibers will be referred to as the second direction (D2), and the direction perpendicular to the first and second directions will be referred to as the third direction (D3). The first direction D1 corresponds to the width direction of the optical fiber ribbon core, the second direction D2 corresponds to the length direction of the optical fiber ribbon core, and the third direction D3 corresponds to the thickness direction of the optical fiber ribbon core.

[0013] [Configuration of Optical Fiber Ribbon] Figure 1A is a schematic plan view of the optical fiber ribbon 10, Figure 1B is a cross-sectional view of line A-A in Figure 1A, and Figure 1C is a cross-sectional view of line B-B in Figure 1A.

[0014] As shown in Figures 1A to C, the optical fiber ribbon cable 10 has multiple single-core coated optical fibers (hereinafter also simply referred to as "optical fibers") 20, multiple connecting portions 30, and multiple separating portions 40. In Figure 1A, the connecting portions 30 are shown in black to make them easier to distinguish from the separating portions 40.

[0015] Multiple optical fibers 20 are arranged in parallel in a first direction D1. The number of optical fibers 20 is not particularly limited as long as there are two or more. The number of optical fibers 20 included in one optical fiber ribbon cable 10 is appropriately selected depending on the application of the optical fiber ribbon cable 10. For example, the number of optical fibers 20 included in one optical fiber ribbon cable 10 is in the range of 2 to 12. In this embodiment, 12 optical fibers 20 are arranged in parallel in one optical fiber ribbon cable 10.

[0016] As shown in Figures 1B and 1C, the single-core coated optical fiber 20 has optical fiber strands 21, a primary coating layer 22, and a secondary coating layer 23. The optical fiber strands 21, primary coating layer 22, and secondary coating layer 23 can be the same as those of known optical fibers, the first coating layer, and the second coating layer. A colored layer may be further formed on the secondary coating layer 23 of the optical fiber 20. It is preferable that the colors of the colored layers of multiple optical fibers 20 within a single optical fiber ribbon cable 10 are different from each other. This makes it possible to distinguish between multiple optical fibers 20 within a single optical fiber ribbon cable 10.

[0017] In this embodiment, a tape layer 41 is further arranged around a plurality of optical fibers 20, and adjacent optical fibers 20 are intermittently connected by the tape layer 41. In this embodiment, the portion of the tape layer 41 that connects adjacent optical fibers 20 is the connecting portion 30, and the space that separates adjacent optical fibers 20 (the region without the tape layer 41) is the separating portion 40.

[0018] The connecting portion 30 is positioned between all adjacent optical fibers 20, partially connecting them. The separating portion 40 is positioned between all adjacent optical fibers 20, partially separating them. The arrangement of the connecting portion 30 and the separating portion 40 is not particularly limited. In the optical fiber ribbon cable 10 of this embodiment, the connecting portion 30 and the separating portion 40 are arranged alternately in the longitudinal direction (second direction D2) of the optical fiber ribbon cable 10. Furthermore, in the optical fiber ribbon cable 10, it is preferable that two or more separating portions 40 are positioned between adjacent connecting portion 30 in the width direction (first direction D1) of the optical fiber ribbon cable 10. In the optical fiber ribbon cable 10 of this embodiment, two separating portions 40 are positioned between adjacent connecting portion 30 in the width direction (first direction D1) of the optical fiber ribbon cable 10. This reduces the number of connecting portions 30, thereby shortening the overall width of the optical fiber ribbon cable 10. Furthermore, it is preferable that the multiple spacing portions 40 are arranged such that the extent of existence of two adjacent spacing portions 40 in the length direction (second direction D2) of the optical fiber ribbon core 10 partially overlaps in the width direction (first direction D1) of the optical fiber ribbon core 10.

[0019] As shown in Figure 1A, the length L1 of the connecting portion 30 when the optical fiber ribbon core 10 is viewed from above is not particularly limited. The length L1 is, for example, within the range of 5 mm to 15 mm. Also, as shown in Figure 1B, the thickness T of the connecting portion 30 is not particularly limited. The thickness T is, for example, within the range of 209 μm to 290 μm. When the length L1 and thickness T of the connecting portion 30 are within this range, 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 core 10 is wound or twisted in the width direction. On the other hand, as shown in Figure 1A, the length L2 of the separating portion 40 when the optical fiber ribbon core 10 is viewed from above is not particularly limited. The length L2 is, for example, within the range of 45 mm to 55 mm. When the length L2 of the separating portion 40 is within this range, it becomes easier to wind or twist the optical fiber ribbon core 10 in the width direction when housing the optical fiber ribbon core 10 in the cable. In this embodiment, length L1, thickness T, and length L2 are the average values ​​obtained when measured at any five locations within the optical fiber ribbon core 10.

[0020] [Configuration of the Optical Fiber Ribbon Manufacturing Apparatus] Next, the optical fiber ribbon manufacturing apparatus 100 will be described. Figure 2 is a perspective view of the optical fiber ribbon manufacturing apparatus 100.

[0021] As shown in Figure 2, the optical fiber ribbon core manufacturing apparatus 100 has a heating section 110, a coating section 120, a removal section 130, and a hardening section 150. The optical fiber ribbon core manufacturing apparatus 100 manufactures an optical fiber ribbon core 10 in which adjacent optical fibers 20 are partially connected, by feeding a plurality of optical fibers 20 arranged in parallel in a first direction D1 in a second direction D2 which is the longitudinal direction of the plurality of optical fibers 20.

[0022] The heating unit 110 heats the multiple optical fibers 20 before they are coated with the uncured resin in the coating unit 120. It is preferable that the heating unit 110 heats the multiple optical fibers 20 immediately before they are coated with the uncured resin.

[0023] As described above, in conventional methods and apparatus for manufacturing optical fiber ribbons, when attempting to manufacture a high-density optical fiber ribbon 10 by arranging small-diameter optical fibers 20 at a narrow pitch, adjacent optical fibers 20 would come into contact with each other after the uncured resin was applied, making it impossible to properly form the separated portions 40. The inventors investigated this phenomenon and found that when small-diameter optical fibers 20 are arranged at a narrow pitch, the surface tension of the uncured resin causes adjacent optical fibers 20 to come into contact with each other. Therefore, in the method and apparatus for manufacturing optical fiber ribbons 10 according to this embodiment, in order to reduce the effect of this surface tension, the multiple optical fibers 20 are heated before being coated with the uncured resin. By doing so, it is possible to suppress a significant drop in the temperature of the resin when the uncured resin (heated to, for example, about 50°C) is applied to the multiple optical fibers 20. The surface tension of the resin depends on the temperature, and the higher the temperature of the resin, the lower the surface tension of the resin. Therefore, by heating multiple optical fibers 20 to reduce the surface tension of the resin, it is possible to prevent adjacent optical fibers 20 from coming into contact with each other after the uncured resin has been applied, even when small-diameter optical fibers 20 are arranged at a narrow pitch.

[0024] The heating temperature of the multiple optical fibers 20 is not particularly limited as long as it is higher than the ambient temperature (room temperature; for example, 20°C or 23°C). For example, the heating unit 110 heats the multiple optical fibers 20 so that the temperature of the multiple optical fibers 20 when they are coated with uncured resin in the coating unit 120 is 25°C or higher, preferably 30°C or higher. The upper limit of the temperature of the multiple optical fibers 20 when they are coated with uncured resin is not particularly limited, for example, 80°C. The configuration of the heating unit 110 is not particularly limited as long as it can heat the entire surface of the multiple optical fibers 20 uniformly and without variation for each optical fiber 20, and can perform the above function. Examples of heating units include hot jets and tubular furnaces.

[0025] The type and diameter of the optical fiber 20 are not particularly limited. As described above, when using a small-diameter optical fiber 20, adjacent optical fibers 20 tend to come into contact with each other due to the surface tension of the uncured resin. However, with the manufacturing apparatus 100 and manufacturing method according to this embodiment, contact between adjacent optical fibers 20 can be prevented even when using small-diameter optical fibers 20. Therefore, for example, optical fibers 20 with a diameter of less than 250 μm, a diameter of 200 μm or less, or a diameter of 160 μm or less may be used.

[0026] The coating portion 120 forms an uncured tape layer 41 by coating a plurality of optical fibers 20 arranged in parallel at a predetermined pitch with an uncured photocurable resin (hereinafter also simply referred to as "uncured resin"). The configuration of the coating portion 120 is not particularly limited as long as it can perform the above function. In this embodiment, the coating portion 120 has a die (not shown). The die has an insertion hole through which a plurality of optical fibers 20 arranged in parallel in a first direction D1 pass, and the shape of the opening of the insertion hole is the shape of the cross-section perpendicular to the length direction of the tape layer 41. By feeding the plurality of optical fibers 20 arranged in parallel at a predetermined pitch and coating them with the uncured resin using the die, a tape layer 41 can be formed on a plurality of optical fibers 20 in a continuous manner and in one go. The pitch (center-to-center distance) of the plurality of optical fibers 20 is not particularly limited as long as it is greater than the diameter of the optical fiber. As described above, when thin-diameter optical fibers 20 are arranged at a narrow pitch, adjacent optical fibers 20 tend to come into contact with each other due to the surface tension of the uncured resin. However, with the manufacturing apparatus 100 and manufacturing method according to this embodiment, contact between adjacent optical fibers 20 can be prevented even when thin-diameter optical fibers 20 are arranged at a narrow pitch. Therefore, the pitch of the multiple optical fibers 20 may be, for example, about the diameter of the optical fiber + 50 μm.

[0027] The removal section 130 partially removes the uncured resin between adjacent optical fibers 20 from a plurality of optical fibers 20 that are coated with uncured resin, thereby forming a separated section 40 where adjacent optical fibers 20 are partially separated and a connected section 30 where adjacent optical fibers 20 are partially connected.

[0028] The configuration of the removal unit 130 is not particularly limited as long as it can perform the above functions. Figures 3A and 3B are diagrams illustrating an example of the removal unit 130 shown in Figure 2. Figure 3A is a plan view of the positioning unit 132, and Figure 3B is a cross-sectional view taken along line A-A shown in Figure 3A. Figure 3B also shows a part of the suction unit 133 located on top of the positioning unit 132. As shown in Figures 3A and 3B, the removal unit 130 is positioned between adjacent optical fibers 20 and includes a plurality of rotating blades 131 for intermittently pushing out the uncured resin between adjacent optical fibers 20, a positioning unit 132 for positioning the optical fibers 20 covered with uncured resin relative to the plurality of rotating blades 131, and a suction unit 133 for sucking up the uncured resin pushed out by the plurality of rotating blades 131.

[0029] The positioning unit 132 includes a positioning unit body 134, a through hole 135 for passing multiple optical fibers 20 covered with uncured resin, multiple slits 136 communicating with the through hole 135 and for multiple rotating blades 131 to rotate inside, and multiple outlet openings 136a for the slits 136 from which the resin extruded by the multiple rotating blades 131 comes out. The through hole 135, the multiple slits 136, and the outlet openings 136a are provided in the positioning unit body 134.

[0030] Multiple rotating blades 131 partially extrude the uncured resin between adjacent optical fibers 20. Each of the multiple rotating blades 131 is positioned inside each of the multiple slits 136. The ends of the rotating blades 131 on the side of the exit opening 136a of the slit 136 are positioned closer to the exit opening 136a of the slit 136 than the upper end of the incoming optical fiber 20. The rotation of the multiple rotating blades 131 is controlled by a motor (not shown) and rotates in accordance with the transport of the optical fiber 20, with their rotation axes 137 coinciding. The shapes of the multiple rotating blades 131 may all be the same, or they may be different. In this embodiment, all of the multiple rotating blades 131 have the same shape.

[0031] Figures 4A and 4B are schematic diagrams showing the configuration of the rotating blade 131. Figure 4A shows only one rotating blade 131, and Figure 4B shows three rotating blades 131. As shown in Figure 4A, in this embodiment, the rotating blade 131 has a notch 138 and a blade portion 139. The circumferential length of the notch 138 corresponds to the length of the connecting portion 30, and the circumferential length of the blade portion 139 corresponds to the length of the separating portion 40. The number of rotating blades 131 is the same as the number of slits 136. As shown in Figure 4B, the multiple rotating blades 131 are arranged such that the position of the notch 138 differs between adjacent rotating blades 131. When the rotating blades 131 rotate in accordance with the transport of the optical fiber 20, the multiple rotating blades 131 rotate while the positions of the notches 138 of each of the multiple rotating blades 131 remain different, and the connecting portion 30 and the separating portion 40 are formed alternately. The positions of the notches 138 in each of the multiple rotating blades 131 are appropriately set according to the positions of the connecting portion 30 and the separating portion 40 in the optical fiber ribbon core 10. Specifically, when the notches 138 are located between adjacent optical fibers 20, the uncured photocurable resin is not pushed out, and a connecting portion 30 is formed. On the other hand, when the blades 139 are located between adjacent optical fibers 20, the uncured resin is pushed out from between the adjacent optical fibers 20, so that the uncured resin is no longer present between the adjacent optical fibers 20 and a separating portion 40 is formed.

[0032] Although not specifically shown in the figures, it is preferable that the rotating blade 131 is positioned such that the distance between the rotating blade 131 and the optical fiber 20 is in the range of 0 to 10 μm, and more preferably in the range of 0 to 5 μm. By shortening the distance between the rotating blade 131 and the optical fiber 20 in this way, the tape layer 41 formed on the side surface of the optical fiber 20 can be made thinner (see Figure 1B).

[0033] As described above, the positioning unit 132 has a positioning unit body 134, a through hole 135, a plurality of slits 136, and an exit opening 136a.

[0034] In this embodiment, the positioning unit body 134 is formed in a substantially rectangular parallelepiped shape. The positioning unit body 134 has through holes 135 for passing multiple optical fibers 20 through, multiple slits 136 for each of the multiple rotating blades 131 to rotate inside, and multiple outlet openings 136a of the slits 136 through which the resin extruded by the multiple rotating blades 131 comes out.

[0035] The through-hole 135 allows multiple optical fibers 20, which are coated with uncured resin, to pass through. In this embodiment, the through-hole 135 opens on the back surface 134a (right side in Figure 3B) and the front surface 134b (left side in Figure 3B) of the positioning unit body 134. The cross-sectional shape of the through-hole 135 in the direction along the third direction D3 and the first direction D1 is complementary to the cross-section of the optical fiber 20 coated with uncured resin.

[0036] Multiple slits 136 are configured so that multiple rotating blades 131 can rotate within them. The multiple slits 136 are arranged along a second direction D2 and in parallel with the first direction D1. The exit opening 136a of the slit 136 opens onto the surface of the positioning unit body 134 on the suction unit 133 side (the top surface in this embodiment). The downstream end of the slit 136 opens onto the front surface 134b of the positioning unit body 134. The multiple slits 136 may all be the same shape, or they may all be different shapes. In this embodiment, all the multiple slits 136 are the same shape. The number of slits 136 is equal to or greater than the number of spaces between adjacent optical fibers 20. In this embodiment, the number of spaces between adjacent optical fibers 20 is 11, so there are 11 slits 136.

[0037] Since the rotating blade 131 is positioned in the slit 136, the uncured resin is pushed out from the exit opening 136a of the slit. Also, as described above, since the rotating blade 131 follows the transport of the optical fiber 20, stress is generated in the direction of the optical fiber 20's movement on the uncured resin pushed out from the slit 136 by the rotating blade 131. At this time, since the downstream end of the slit 136 opens to the front surface 134b of the positioning unit body 134, the uncured resin does not get stuck and is prevented from coming into contact with the optical fiber 20 again.

[0038] The suction unit 133 sucks up the uncured resin extruded from the outlet opening 136a of the slit 136. The suction unit 133 has an intake unit 141, a negative pressure device (not shown), and a connecting unit 142 for connecting the intake unit 141 and the negative pressure device.

[0039] The intake section 141 is formed in a hollow box shape and has a suction opening 141a that is positioned to cover the multiple outlet openings 136a of the multiple slits 136 from which the resin extruded by the multiple rotating blades 131 comes out. Preferably, the downstream end of the suction opening 141a is positioned further downstream than the downstream ends of the multiple outlet openings 136a. This allows for proper suction of the uncured resin accumulated downstream of the multiple outlet openings 136a, and prevents the uncured resin accumulated downstream of the multiple outlet openings 136a from coming into contact with the optical fiber 20 again. Also, the upstream end of the suction opening 141a is positioned further upstream than the upstream ends of the multiple outlet openings 136a. In this embodiment, the upstream end of the suction opening 141a is positioned at the same location as the upstream ends of the multiple outlet openings 136a.

[0040] Furthermore, the length of the suction opening 141a in the direction of arrangement of the multiple optical fibers 20 (first direction D1) is preferably within the range of 100 to 120% of the length of the multiple outlet openings 136a in the direction of arrangement of the multiple optical fibers 20. Here, "L3 length of the multiple outlet openings 136a in the direction of arrangement of the multiple optical fibers 20" means the length between the outer end of the slit 136 located at one end in the first direction D1 (the outer end of the lower slit 136 in the example shown in Figure 3A) and the outer end of the slit 136 located at the other end in the first direction D1 (the outer end of the upper slit 136 in the example shown in Figure 3A). This reduces the volume of the space surrounded by the upper surface of the intake section 141 and the positioning section body 134, allowing the space to be efficiently subjected to negative pressure by the suction device. Therefore, the uncured resin can be efficiently and appropriately aspirated.

[0041] The connection section 142 connects to the intake section 141 and a negative pressure device (not shown). In this embodiment, the connection section 142 is connected to the surface of the intake section 141 opposite to the suction opening 141a. By operating the negative pressure device, the space surrounded by the intake section 141 and the upper surface of the positioning section body 134 can be made into a negative pressure state, and the uncured resin that has been pushed into the space is sucked up without sucking up the uncured resin remaining around the multiple optical fibers 20. The conditions for sucking up the uncured resin that has been pushed into the space without sucking up the uncured resin remaining around the multiple optical fibers 20 are appropriately adjusted by the volume of the space and the suction pressure from the negative pressure device. It is preferable that the negative pressure device is constantly running during the manufacturing of the optical fiber ribbon core 10.

[0042] The curing unit 150 cures the uncured resin remaining in the plurality of optical fibers 20. The configuration of the curing unit 150 is not particularly limited as long as it can exhibit the above functions. In the present embodiment, the curing unit 150 includes a first light irradiation unit 151 and a second light irradiation unit 152. The first light irradiation unit 151 is disposed on the upstream side and irradiates light onto the tape layer 41 to semi-cure the uncured tape layer 41. The second light irradiation unit 152 further irradiates light to fully cure the semi-cured tape layer 41. In the present embodiment, the integrated irradiation amount of the first light irradiation unit 151 is less and the integrated irradiation amount of the second light irradiation unit 152 is greater, such that the integrated irradiation amounts of the first light irradiation unit 151 on the upstream side and the second light irradiation unit 152 on the downstream side are adjusted respectively.

[0043] [Method for manufacturing an optical fiber ribbon core wire] Next, a method for manufacturing an optical fiber ribbon core wire will be described. FIG. 5 is a flowchart of the method for manufacturing an optical fiber ribbon core wire.

[0044] As shown in FIG. 5, the method for manufacturing an optical fiber ribbon core wire includes a step of heating a plurality of optical fibers (S110), a step of coating the plurality of optical fibers with an uncured resin (S120), a step of partially removing the uncured resin (S130), and a step of curing the resin (S140).

[0045] In the step of heating a plurality of optical fibers (S110), the plurality of optical fibers 20 are heated. For example, the plurality of optical fibers 20 arranged in parallel may be heated using the heating unit 110 of the manufacturing apparatus shown in FIG. 2. Specifically, while feeding the plurality of optical fibers 20, the plurality of optical fibers 20 are heated to a predetermined temperature.

[0046] In the step of coating multiple optical fibers with an uncured resin (S120), multiple heated optical fibers 20 arranged in parallel at a predetermined pitch are coated with the uncured resin. At this time, the temperature of the optical fibers 20 immediately before coating with the uncured resin is higher than the ambient temperature. For example, the temperature of the multiple optical fibers 20 is in the range of 25 to 80°C. Therefore, the temperature of the uncured resin does not decrease easily, and the surface tension of the resin does not increase. As a result, even when multiple small-diameter optical fibers 20 are arranged at a narrow pitch, it is possible to prevent adjacent optical fibers 20 from coming into contact with each other when the multiple optical fibers 20 are coated with the uncured resin. For example, the coating section 120 of the manufacturing apparatus shown in Figure 2 may be used to form the uncured tape layer 41. Specifically, while feeding the multiple optical fibers 20, the uncured resin is applied in a tape-like manner to the multiple optical fibers 20 using a die to form the tape layer 41.

[0047] In the step of partially removing the uncured resin (S130), the uncured resin between adjacent optical fibers is partially removed in a plurality of optical fibers 20 coated with uncured resin. For example, the removal unit 130 of the manufacturing apparatus shown in Figures 2, 3A, and 3B may be used to form the connecting portion 30 and the separating portion 40. Specifically, a plurality of rotating blades 131 are rotated on the tape layer 41 to remove a portion of the tape layer 41 and form the connecting portion 30 and the separating portion 40. As the rotating blades 131 rotate in accordance with the transport of the optical fibers 20, the separating portion 40 and the connecting portion 30 are formed alternately. At this time, the uncured resin removed by the rotating blades 131 is pushed out toward the exit opening 136a of the slit 136. The uncured resin pushed out from the exit opening 136a of the slit 136 is sucked up by the suction unit 133.

[0048] In the resin curing step (S140), the uncured resin remaining on the multiple optical fibers 20 is cured. For example, the curing unit 150 of the manufacturing apparatus shown in Figure 2 may be used to partially cure the uncured tape layer 41 by irradiating it with light from the first light irradiation unit 151, and then completely cure the partially cured tape layer 41 by irradiating it with light from the second light irradiation unit 152.

[0049] Even when a plurality of small-diameter optical fibers 20 are arranged at a narrow pitch, an optical fiber ribbon core wire 10 in which a plurality of connection portions 30 and a plurality of separation portions 40 are appropriately formed can be manufactured by the above procedure.

[0050] (Effect) As described above, according to the present invention, since the plurality of optical fibers 20 are heated before being coated with the uncured resin, the surface tension of the uncured resin after the plurality of optical fibers 20 are coated with the uncured resin can be reduced. Therefore, according to the present invention, even when a plurality of small-diameter optical fibers 20 are arranged at a narrow pitch, it is possible to prevent adjacent optical fibers 20 from contacting each other when the plurality of optical fibers 20 are coated with the uncured resin. As a result, a plurality of connection portions 30 and a plurality of separation portions 40 can be appropriately formed. Therefore, according to the present invention, it is possible to manufacture a high-density optical fiber ribbon core wire 10 (an optical fiber ribbon core wire having a small width) by arranging small-diameter optical fibers 20 at a narrow pitch.

[0051] An optical fiber ribbon core wire including 12 single-core coated optical fibers was manufactured using the manufacturing apparatus 100 shown in FIG. 2. The diameter of the single-core coated optical fiber was 200 μm. In the coating portion 120, a urethane acrylate-based photocurable resin was applied to 12 single-core coated optical fibers arranged in parallel at a pitch (center-to-center distance) of 250 μm. The length of the notch portion 138 (corresponding to the length of the connection portion) on the outer peripheral circle of the rotary blade 131 of the removing portion 130 was 10 mm, and the length of the blade portion 139 (corresponding to the length of the separation portion) was 50 mm. A hot jet was used as the heating portion 110, and the heating temperature was changed for each sample. The ambient temperature was 20° C., and the temperature of the single-core coated optical fiber when being coated with the uncured resin in the coating portion 120 was 20° C., 25° C., 30° C., 50° C., or 80° C.

[0052] For each sample, a 1m length was evaluated to determine whether the connecting and separating sections were properly formed. The entire optical fiber ribbon core was evaluated as follows: Pass (○) if the connecting and separating sections were properly and alternately formed; Pass (△) if there were one or two locations where the connecting and separating sections were not properly and alternately formed; and Fail (×) if there were three or more locations where the connecting and separating sections were not properly and alternately formed.

[0053] Table 1 shows the presence or absence of heating, the temperature of the optical fiber during coating, and the evaluation results for each sample.

[0054]

[0055] As shown in Table 1, in sample No. 1, which was not heated before coating with resin, the optical fibers were partially in contact with each other, and there were areas where the spacing was not properly formed. This is thought to be because, after the 12 optical fibers were coated with resin in the coating portion 120, the surface tension of the resin caused them to be pulled together in the width direction, resulting in contact between adjacent optical fibers. On the other hand, in samples No. 2 to 5, which were heated before coating with resin, the connecting portions and spacing portions were properly and alternately formed. From this, it can be seen that even when arranging multiple small-diameter optical fibers at a narrow pitch, it is possible to manufacture optical fiber ribbons with properly formed connecting portions and spacing portions by heating them at an appropriate temperature before coating with resin.

[0056] The method and apparatus for manufacturing optical fiber ribbon cores according to the present invention are useful, for example, for manufacturing optical fiber ribbon cores used in high-speed, high-capacity optical fiber communication networks.

[0057] 10 Optical fiber ribbon core 20 Optical fiber (single-core coated optical fiber) 21 Optical fiber strand 22 Primary coating layer 23 Secondary coating layer 30 Connecting section 40 Separating section 41 Tape layer 100 Manufacturing apparatus 110 Heating section 120 Coating section 130 Removal section 131 Rotating blade 132 Positioning section 133 Suction section 134 Positioning section body 134a Back view 134b Front view 135 Through hole 136 Slit 136a Exit opening 137 Rotating shaft 138 Notch 139 Blade section 141 Intake section 141a Suction opening 142 Connection section 150 Hardening section 151 First light irradiation section 152 Second light irradiation section

Claims

1. A method for manufacturing an optical fiber ribbon core in which a plurality of single-core coated optical fibers are partially connected, comprising the step of heating the plurality of single-core coated optical fibers before coating them with an uncured resin.

2. A method for manufacturing an optical fiber ribbon core according to claim 1, wherein the temperature of the plurality of single-core coated optical fibers when coated with the uncured resin is in the range of 25 to 80°C.

3. A method for manufacturing an optical fiber ribbon core according to claim 1, further comprising: a step of coating a plurality of heated single-core coated optical fibers with the uncured resin; a step of partially removing the uncured resin between adjacent single-core coated optical fibers among the plurality of single-core coated optical fibers coated with the uncured resin; and a step of curing the uncured resin remaining on the plurality of single-core coated optical fibers.

4. An apparatus for manufacturing an optical fiber ribbon core in which a plurality of single-core coated optical fibers are partially connected, comprising: a heating unit for heating the plurality of single-core coated optical fibers; a coating unit for coating the heated plurality of single-core coated optical fibers with an uncured resin; a removal unit for partially removing the uncured resin between adjacent single-core coated optical fibers among the plurality of single-core coated optical fibers coated with the uncured resin; and a curing unit for curing the uncured resin remaining on the plurality of single-core coated optical fibers.

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