Optical fiber ribbon and method for manufacturing optical fiber ribbon

Abstract

To improve fiber cord separability of an optical fiber ribbon.SOLUTION: An optical fiber ribbon includes: an optical fiber bare wire; a plurality of optical fiber colored core wires including a primary layer which coats the optical fiber bare wire and is formed of a first ultraviolet curable resin, a secondary layer which coats the primary layer and is formed of a second ultraviolet curable resin, and a colored layer which coats the secondary layer and is formed of a third ultraviolet curable resin; and a ribbon layer which coats the plurality of optical fiber colored core wires and is formed of a fourth ultraviolet curable resin, wherein a conversion ratio of a part contacting the colored layer in the ribbon layer is 83.7% or more, and breaking elongation of the ribbon layer is 9.4% or more.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to optical fiber ribbons and methods for manufacturing optical fiber ribbons. [Background technology]

[0002] Technologies have been proposed to improve the individual fiber separation property of optical fiber ribbons. The technology described in Patent Document 1 improves the individual fiber separation property of optical fiber ribbons by setting the surface conversion rate of the colored layer of the colored optical fiber core wires high. The individual fiber separation property of optical fiber ribbons refers to the ease of removing the colored optical fiber core wires from the optical fiber ribbon. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 017060 Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the manufacturing conditions of the colored optical fiber core, it may not be easy to set a high surface conversion rate of the colored layer, which may make it difficult to improve the separation ability of the optical fiber ribbon.

[0005] An object of the present invention is to improve the separation of individual fibers of an optical fiber ribbon. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided an optical fiber ribbon comprising: a plurality of colored optical fiber core wires including a bare optical fiber; a primary layer formed of a first ultraviolet-curable resin covering the bare optical fiber; a secondary layer formed of a second ultraviolet-curable resin covering the primary layer; and a colored layer formed of a third ultraviolet-curable resin covering the secondary layer; and a ribbon layer formed of a fourth ultraviolet-curable resin covering the plurality of colored optical fiber core wires, wherein a conversion rate of a portion of the ribbon layer in contact with the colored layer is 83.7% or more, and a breaking elongation of the ribbon layer is 9.4% or more.

[0007] According to another aspect of the present invention, there is provided an optical fiber ribbon comprising: a plurality of colored optical fiber core wires including a bare optical fiber, a primary layer formed of a first ultraviolet-curable resin covering the bare optical fiber, and a secondary layer formed of a second ultraviolet-curable resin covering the primary layer; and a ribbon layer formed of a fourth ultraviolet-curable resin covering the plurality of colored optical fiber core wires, wherein the secondary layer is a colored layer, a conversion rate of a portion of the ribbon layer in contact with the colored layer is 83.7% or more, and a breaking elongation of the ribbon layer is 9.4% or more.

[0008] According to another aspect of the present invention, there is provided a method for manufacturing an optical fiber ribbon, comprising the steps of: drawing a bare optical fiber from an optical fiber preform; applying a first ultraviolet-curable resin to form a primary layer around the bare optical fiber and irradiating the first ultraviolet-curable resin with ultraviolet light from a first light source to form a primary layer; applying a second ultraviolet-curable resin to form a secondary layer around the primary layer and irradiating the second ultraviolet-curable resin with ultraviolet light from a second light source to form a secondary layer; applying a third ultraviolet-curable resin to form a colored layer around the secondary layer and irradiating the third ultraviolet-curable resin with ultraviolet light from a third light source to form a colored layer; and applying a fourth ultraviolet-curable resin to form a ribbon layer around the colored layer and irradiating the fourth ultraviolet-curable resin with ultraviolet light from a fourth light source to form a ribbon layer, wherein a conversion rate of a portion of the ribbon layer in contact with the colored layer is 83.7% or more and a breaking elongation of the ribbon layer is 9.4% or more.

[0009] According to another aspect of the present invention, there is provided a method for manufacturing an optical fiber ribbon, comprising the steps of: drawing a bare optical fiber from an optical fiber preform; applying a first ultraviolet-curable resin to form a primary layer around the bare optical fiber and irradiating the first ultraviolet-curable resin with ultraviolet light from a first light source to form a primary layer; applying a second ultraviolet-curable resin to form a secondary layer around the primary layer and irradiating the second ultraviolet-curable resin with ultraviolet light from a second light source to form a colored secondary layer; and applying a fourth ultraviolet-curable resin to form a ribbon layer around the secondary layer and irradiating the fourth ultraviolet-curable resin with ultraviolet light from a fourth light source to form a ribbon layer, wherein a conversion rate of a portion of the ribbon layer in contact with the secondary layer is 83.7% or more and a breaking elongation of the ribbon layer is 9.4% or more. Effect of the Invention

[0010] According to the present invention, the separation property of the optical fiber ribbon can be improved. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view of a colored optical fiber core according to an embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view of an optical fiber ribbon according to one embodiment. [Diagram 3] 1 is a schematic diagram showing a portion of a manufacturing apparatus used in a method for manufacturing an optical fiber ribbon according to an embodiment of the present invention. [Figure 4] 1 is a schematic diagram showing a portion of a manufacturing apparatus used in a method for manufacturing an optical fiber ribbon according to an embodiment of the present invention. [Diagram 5] 1 is a schematic diagram showing a portion of a manufacturing apparatus used in a method for manufacturing an optical fiber ribbon according to an embodiment of the present invention. [Figure 6] 2 is a flowchart of a method for manufacturing an optical fiber ribbon according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Elements having common functions are designated by the same reference numerals throughout the drawings, and duplicated descriptions may be omitted or simplified.

[0013] 1 is a cross-sectional view of a colored optical fiber according to this embodiment. The colored optical fiber 6 includes an optical fiber 1 and a colored layer 5 that covers the outer periphery of the optical fiber 1. The optical fiber 1 also includes a bare optical fiber 2, a primary layer 3 that covers the outer periphery of the bare optical fiber 2, and a secondary layer 4 that covers the outer periphery of the primary layer 3. The bare optical fiber 2 is covered with three coating layers, namely the primary layer 3, the secondary layer 4, and the colored layer 5.

[0014] The bare optical fiber 2 is formed of, for example, silica-based glass and transmits light. The primary layer 3 is a soft layer and has a function of buffering external forces applied to the bare optical fiber 2. The Young's modulus of the primary layer 3 may preferably be 0.1 MPa or more and 2.0 MPa or less. The secondary layer 4 is a hard layer and has a function of protecting the bare optical fiber 2 and the primary layer 3 from external forces. The Young's modulus of the secondary layer 4 may preferably be 500 MPa or more and 2000 MPa or less. The colored layer 5 is colored to identify the colored optical fiber core 6. The colored layer 5 may be the secondary layer 4 colored with a coloring agent. The coloring agent may be a mixture containing a pigment or a lubricant.

[0015] The diameter of the optical fiber 1 may be 190 μm or more and 260 μm or less. The diameter of the bare optical fiber 2 may be 80 μm or more and 150 μm or less, and preferably 124 μm or more and 126 μm or less. The thickness of the primary layer 3 may be 5 μm or more and 60 μm or less. The thickness of the secondary layer 4 may be 5 μm or more and 60 μm or less. The thickness of the colored layer 5 may be several μm. Here, the diameter of the optical fiber 1 may be determined by the sum of the diameter of the bare optical fiber 2, the length twice the thickness of the primary layer 3, and the length twice the thickness of the secondary layer 4. Therefore, the diameter of the bare optical fiber 2, the thickness of the primary layer 3, and the thickness of the secondary layer 4 may be selected so that the diameter of the optical fiber 1 is 190 μm or more and 260 μm or less.

[0016] When an external force is applied to the bare optical fiber 2, a transmission loss of light (microbend loss) occurs due to minute deformation of the bare optical fiber 2. By setting the Young's modulus of the primary layer 3 low, the function of buffering the external force of the primary layer 3 is improved, and the microbend loss of the colored optical fiber 6 is suppressed. The microbend loss of the optical fiber strand 1 and the colored optical fiber 6 according to this embodiment can be 0.4 dB / km or less.

[0017] The Young's modulus of the primary layer 3 of the optical fiber is ISM (In Situ Modulus), and the Young's modulus of the primary layer 3 can be measured by the following method.

[0018] First, a commercially available stripper is used to strip off the primary layer 3 and the secondary layer 4 from the middle of the sample optical fiber by a length of several mm, and then one end of the optical fiber on which the coating layer is formed is fixed on a slide glass with an adhesive, and a load F is applied to the other end of the optical fiber on which the coating layer is formed. In this state, the displacement δ of the primary layer 3 at the boundary between the part where the coating layer is stripped off and the part where the coating is formed is read under a microscope. Then, the rate (slope) of the change in the load F with respect to the displacement δ is calculated by setting the load F to 10, 20, 30, 50, and 70 gf (i.e., 98, 196, 294, 490, and 686 mN, respectively). The primary elastic modulus is calculated using the calculated slope and the following formula (1). The calculated primary elastic modulus is the so-called ISM, and hereinafter the primary elastic modulus is appropriately referred to as P-ISM. When drawing the optical fiber, the drawing speed and the irradiance of the ultraviolet light are controlled to adjust the P-ISM. P-ISM=(3F / δ)*(1 / 2πl)*ln(DP / DG) ···(1)

[0019] The unit of P-ISM is [MPa]. In the right side of formula (1), F / δ is the rate (slope) of change in load (F) [gf] relative to displacement (δ) [μm], l is the sample length (e.g., 10 mm), and DP / DG is the ratio of the outer diameter (DP) [μm] of the primary layer 3 to the outer diameter (DG) [μm] of the cladding of the optical fiber. Therefore, when calculating P-ISM using formula (1) from the F, δ, and l used, a predetermined unit conversion is required. The outer diameter of the primary layer 3 and the outer diameter of the cladding can be measured by observing the cross section of the optical fiber cut by a fiber cutter under a microscope.

[0020] Furthermore, the Young's modulus of the secondary layer 4 of the optical fiber is an ISM (In Situ Modulus), and the Young's modulus of the secondary layer 4 can be measured by the following method.

[0021] First, an optical fiber is immersed in liquid nitrogen, and the coating layer is stripped off with a stripper to prepare a hollow cylindrical sample with only the coating layer by pulling out the bare optical fiber 2 from the optical fiber. The end of the sample is fixed to an aluminum plate using an adhesive. The aluminum plate part is chucked using a Tensilon universal tensile tester in an atmosphere with a temperature of 23°C and a relative humidity of 50%. Next, the sample is stretched with a width of 6 mm, a gauge interval of 25 mm, and a tensile speed of 1 mm / min, and the force at 2.5% elongation is measured to calculate the elastic modulus S-ISM (2.5% secant modulus) of the secondary layer 4. The coating layer sample includes the primary layer 3 and the secondary layer 4. Since the S-ISM is sufficiently large compared to the P-ISM, the effect of the P-ISM on the measured Young's modulus can be ignored and the measured Young's modulus can be regarded as the S-IPM.

[0022] There are various methods for measuring microbend loss, and the microbend loss can be measured by the following method. First, the transmission loss of an optical fiber wound around a bobbin wrapped with sandpaper is measured, and the transmission loss at this time is defined as the transmission loss of the optical fiber in state A. Next, the transmission loss of an optical fiber wound around a bobbin not wrapped with sandpaper is measured, and the transmission loss at this time is defined as the transmission loss of the optical fiber in state B. The difference between the transmission loss of the optical fiber in state A and the transmission loss of the optical fiber in state B is defined as the microbend loss of the optical fiber. Here, the transmission loss of the optical fiber in state B does not include the transmission loss due to external forces, and is considered to be the transmission loss inherent to the optical fiber. The grit size of the sandpaper is #1000, and the length of the optical fiber is 400 m or more. The optical fibers in states A and B are wound around the bobbin so as not to overlap each other. In other words, the optical fibers in states A and B are wound around the bobbin in a single layer.

[0023] This measurement method is similar to the fixed diameter drum method defined in JIS C6823:2010. This measurement method is also called the sandpaper method. In addition, this measurement method measures the transmission loss at a wavelength of 1550 nm, so the microbend loss in this embodiment is also a value at a wavelength of 1550 nm.

[0024] The effective core area (Aeff) is an index that indicates the susceptibility of an optical fiber to microbend loss. The effective core area (Aeff) is expressed by the following formula (2). The effective core area (Aeff) is described in, for example, C-3-76 and C-3-77 of the 1999 Electronics Society Conference Proceedings of the Institute of Electronics, Information and Communication Engineers. Aeff = (πk / 4) * (MFD) 2 (2) Here, the effective core area Aeff is a value at a wavelength of 1550 nm, MFD is a mode field diameter (μm), and k is a constant. The effective core area Aeff represents the area of ​​a portion of a cross section perpendicular to the axis of the bare optical fiber 2 through which light having a predetermined intensity passes. In general, the larger the effective core area Aeff of the bare optical fiber 2, the weaker the optical confinement in the cross section of the bare optical fiber 2. That is, when the effective core area Aeff of the bare optical fiber 2 is large, the light in the bare optical fiber 2 is more likely to leak out due to an external force applied to the bare optical fiber 2. For this reason, when the effective core area Aeff of the bare optical fiber 2 is large, microbending loss is more likely to occur in the colored optical fiber 6.

[0025] On the other hand, by increasing the effective core area of ​​the bare optical fiber 2, it is possible to reduce the light intensity per unit area in the cross section of the bare optical fiber 2. This makes it possible to suppress the nonlinear optical effect of the bare optical fiber 2.

[0026] The colored optical fiber 6 according to this embodiment has a primary layer 3 that can effectively suppress microbending loss. That is, even when the effective core area of ​​the bare optical fiber 2 is large, the microbending loss of the colored optical fiber 6 can be effectively suppressed.

[0027] The effective core area Aeff of the bare optical fiber 2 is 80 μm 2 More than, for example, 130 μm 2 More than 150μm 2 It is preferable that the above-mentioned condition is satisfied. In this manner, the colored optical fiber 6 capable of suppressing the nonlinear optical effect of the bare optical fiber 2 can be obtained.

[0028] The primary layer 3, the secondary layer 4, and the colored layer 5 are formed by curing an ultraviolet-curable resin by irradiation with ultraviolet light. The ultraviolet-curable resin will be described in detail below.

[0029] The ultraviolet curable resin is a resin that is polymerized and hardened by irradiation with ultraviolet rays. The ultraviolet curable resin is not particularly limited as long as it can be polymerized by irradiation with ultraviolet rays. The ultraviolet curable resin can be polymerized by, for example, photoradical polymerization.

[0030] The ultraviolet-curable resin is, for example, an ultraviolet-curable resin having a polymerizable unsaturated group such as an ethylenically unsaturated group that polymerizes and cures when exposed to ultraviolet light, such as urethane (meth)acrylates such as polyether-based urethane (meth)acrylates and polyester-based urethane (meth)acrylates, epoxy (meth)acrylates, and polyester (meth)acrylates, and preferably has at least two polymerizable unsaturated groups.

[0031] The polymerizable unsaturated group in the ultraviolet curable resin may be, for example, a group having an unsaturated double bond such as a vinyl group, an allyl group, an acryloyl group, or a methacryloyl group, or a group having an unsaturated triple bond such as a propargyl group, etc. Among these, an acryloyl group or a methacryloyl group is preferred in terms of polymerizability.

[0032] The ultraviolet curable resin may be a monomer, oligomer, or polymer that initiates polymerization and hardens upon irradiation with ultraviolet light, but is preferably an oligomer. An oligomer is a polymer having a degree of polymerization of 2 to 100. In this specification, "(meth)acrylate" means one or both of acrylate and methacrylate. The ultraviolet curable resin contains any photopolymerization initiator (photoinitiator) that has sensitivity in the ultraviolet region.

[0033] A polyether-based urethane (meth)acrylate is a compound having a polyether segment, a (meth)acrylate, and a urethane bond, such as a reaction product of a polyol having a polyether skeleton with an organic polyisocyanate compound and a hydroxyalkyl (meth)acrylate. A polyester-based urethane (meth)acrylate is a compound having a polyester segment, a (meth)acrylate, and a urethane bond, such as a reaction product of a polyol having a polyester skeleton with an organic polyisocyanate compound and a hydroxyalkyl (meth)acrylate.

[0034] The ultraviolet-curable resin of the primary layer 3 (first ultraviolet-curable resin) and the ultraviolet-curable resin of the secondary layer 4 (second ultraviolet-curable resin) may contain, in addition to the oligomer and the photoinitiator, a diluting monomer, a photosensitizer, an ultraviolet absorber, an antioxidant, a chain transfer agent, a silane coupling agent, a lubricant such as silicone, and various additives. The diluting monomer may be a monofunctional (meth)acrylate or a polyfunctional (meth)acrylate. Here, the diluting monomer means a monomer for diluting the ultraviolet-curing resin.

[0035] The ultraviolet curable resin of the colored layer 5 (third ultraviolet curable resin) may contain, in addition to the oligomer and monomer, various additives such as a photoinitiator, a photosensitizer, an ultraviolet absorber, an antioxidant, a chain transfer agent, silicone, titanium oxide, etc. The color of the ultraviolet curable resin of the colored layer 5 may be black, gray, blue, light blue, green, yellow, orange, brown, pink, red, or white.

[0036] By incorporating a photoinitiator or photosensitizer that has absorption in the ultraviolet light of a UV-LED (light-emitting diode) into the ultraviolet-curable resin, the curing of the ultraviolet-curable resin by the ultraviolet light of the UV-LED can be promoted. Since the ultraviolet light of the UV-LED has a single wavelength, a non-initiator or photosensitizer that has absorption in the wavelength of the ultraviolet light irradiated by the UV-LED can be adopted. For example, when using a UV-LED that irradiates ultraviolet light with a wavelength of 300 nm or more, the photoinitiator can be, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and the photosensitizer can be, for example, 2,4-diethyl-9H-thioxen-9-one, 2-isopropylthioxanthone.

[0037] 2 is a cross-sectional view of an optical fiber ribbon 8 according to this embodiment. The optical fiber ribbon 8 has a plurality of colored optical fiber core wires 6 and a ribbon layer 7. The plurality of colored optical fiber core wires 6 are arranged side by side. The ribbon layer 7 covers and connects the plurality of colored optical fiber core wires 6. The thickness of the optical fiber ribbon 8 can be 210 μm or more and 400 μm or less. The thickness of the ribbon layer 7 is set so that the thickness of the optical fiber ribbon is 210 μm or more and 400 μm or less.

[0038] The ribbon layer 7 is composed of an ultraviolet curable resin. The ultraviolet curable resin of the ribbon layer 7 (fourth ultraviolet curable resin) may be composed similarly to the ultraviolet curable resin of the primary layer 3 and the ultraviolet curable resin of the secondary layer 4. The Young's modulus of the ribbon layer 7 may preferably be 1.0 MPa or more and 2000 MPa or less. By changing the components constituting the ultraviolet curable resin of the ribbon layer 7, the conversion rate, Young's modulus, breaking elongation, etc. of the ribbon layer 7 can be changed.

[0039] The optical fiber ribbon 8 is not limited to the configuration shown in Fig. 2. The optical fiber ribbon 8 may be an intermittent type optical fiber ribbon. When the optical fiber ribbon 8 is an intermittent type optical fiber ribbon, the optical fiber ribbon 8 forms adhesive parts (ribbon layers 7) intermittently in the longitudinal direction of the colored optical fiber core wires 6 in the region where two adjacent colored optical fiber core wires 6 contact each other.

[0040] The Young's modulus of the ribbon layer 7 can be measured by the following method. The ribbon layer 7 is scraped off from the optical fiber ribbon 8 using an unused single blade. The scraped off ribbon layer 7 is then conditioned at constant temperature and humidity (temperature 23°C, relative humidity 50%) to obtain a sample piece of the ribbon layer 7 having a length of 25 mm. Under constant temperature and humidity conditions (temperature 23°C, relative humidity 50%), the sample piece of the ribbon layer 7 is pulled at a pulling speed of 1 mm / min, and the Young's modulus at 2.5% strain is calculated. The cross-sectional area of ​​the sample piece of the ribbon layer 7 is measured by observation under a microscope.

[0041] Next, a manufacturing apparatus used in the manufacturing method of the optical fiber ribbon according to this embodiment will be described. Fig. 3 is a schematic diagram showing a part of a manufacturing apparatus 10 used in the manufacturing method of the optical fiber ribbon according to this embodiment. The manufacturing apparatus 10 has a heating device 20, a primary layer coating device 30, a secondary layer coating device 40, a guide roller 60, and a winding device 70. The manufacturing apparatus 10 shown in Fig. 3 manufactures an optical fiber 1 from an optical fiber preform BM.

[0042] The optical fiber preform BM is made of, for example, quartz-based glass, and is manufactured by a well-known method such as the VAD method, the OVD method, or the MCVD method. The heating device 20 has a heater 21. The heater 21 can be any heat source such as a tape heater, a ribbon heater, a rubber heater, an oven heater, a ceramic heater, or a halogen heater. An end of the optical fiber preform BM is heated and melted by the heater 21 arranged around the optical fiber preform BM, and is drawn to draw out a bare optical fiber 2.

[0043] A primary layer coating device 30 is provided below the heating device 20. The primary layer coating device 30 has a resin applicator 31 and an ultraviolet ray irradiation device 32 (first light source). The resin applicator 31 holds an ultraviolet ray curable resin for the primary layer 3. The ultraviolet ray curable resin for the primary layer 3 contains the above-mentioned mercapto group-containing compound as an additive. The ultraviolet ray curable resin for the primary layer 3 is applied by the resin applicator 31 to the bare optical fiber 2 drawn out from the optical fiber preform BM.

[0044] An ultraviolet ray irradiation device 32 is provided below the resin application device 31. The ultraviolet ray irradiation device 32 includes any ultraviolet ray light source such as a metal halide lamp, a mercury lamp, a UV-LED, or the like. The resin application device 31 applies an ultraviolet ray curable resin of the primary layer 3 to the bare optical fiber 2, and the bare optical fiber 2 enters the ultraviolet ray irradiation device 32, where the ultraviolet ray curable resin of the primary layer 3 is irradiated with ultraviolet rays. As a result, the ultraviolet ray curable resin of the primary layer 3 is cured, and the primary layer 3 is formed.

[0045] A secondary layer coating device 40 is provided below the primary layer coating device 30. The secondary layer coating device 40 has a resin coating device 41 and an ultraviolet ray irradiation device 42 (second light source). The resin coating device 41 holds an ultraviolet ray curable resin for the secondary layer 4. The ultraviolet ray curable resin for the secondary layer 4 is applied to the primary layer 3 by the resin coating device 41.

[0046] An ultraviolet irradiation device 42 is provided below the resin coating device 41. The ultraviolet irradiation device 42 may be configured similarly to the ultraviolet irradiation device 32. The bare optical fiber 2, in which the ultraviolet-curable resin of the secondary layer 4 is coated around the primary layer 3, enters the ultraviolet irradiation device 42, and ultraviolet light is irradiated onto the ultraviolet-curable resin of the secondary layer 4. As a result, the ultraviolet-curable resin of the secondary layer 4 is cured, and the secondary layer 4 is formed. The bare optical fiber 2 is coated with the primary layer 3 and the secondary layer 4, and the optical fiber strand 1 is formed.

[0047] The resin coating device 31 may be configured to separately hold the ultraviolet curable resin of the primary layer 3 and the ultraviolet curable resin of the secondary layer 4. In this case, the resin coating device 31 coats the ultraviolet curable resin of the primary layer 3 on the bare optical fiber 2, and then coats the ultraviolet curable resin of the secondary layer 4 around the ultraviolet curable resin of the primary layer 3. Furthermore, in this case, the ultraviolet irradiating device 32 irradiates ultraviolet rays onto the ultraviolet curable resin of the primary layer 3 and the ultraviolet curable resin of the secondary layer 4 that have been applied to the bare optical fiber 2. This forms the primary layer 3 and the secondary layer 4. In this case, the manufacturing apparatus 10 does not necessarily need to have the secondary layer coating device 40.

[0048] A guide roller 60 and a winding device 70 are provided below the secondary layer coating device 40. The manufactured optical fiber 1 is guided by the guide roller 60 and wound up by the winding device 70.

[0049] Fig. 4 is a schematic diagram showing a part of a manufacturing apparatus 10 used in the manufacturing method of the optical fiber ribbon according to the present embodiment. The manufacturing apparatus 10 has a colored layer coating device 50, guide rollers 61, 62, and winding devices 70, 71. In Fig. 4, the manufacturing apparatus 10 is an apparatus for manufacturing a colored optical fiber core wire 6 from an optical fiber strand 1.

[0050] The optical fiber 1 wound by the winding device 70 is guided by a guide roller 61 and transported to the colored layer coating device 50.

[0051] The colored layer coating device 50 includes a resin applicator 51 and an ultraviolet ray irradiation device 52 (third light source). The resin applicator 51 holds an ultraviolet ray curable resin for the colored layer 5. The ultraviolet ray curable resin for the colored layer 5 is applied to the optical fiber 1 by the resin applicator 51.

[0052] An ultraviolet irradiator 52 is provided below the resin applicator 51. The ultraviolet irradiator 52 may be configured similarly to the ultraviolet irradiators 32 and 42. The optical fiber 1 coated with the ultraviolet curable resin of the colored layer 5 enters the ultraviolet irradiator 52, and the ultraviolet curable resin of the colored layer 5 is irradiated with ultraviolet light. As a result, the ultraviolet curable resin of the colored layer 5 is cured, and the colored layer 5 is formed. The optical fiber 1 is coated with the colored layer 5, and a colored optical fiber core 6 is formed.

[0053] Below the colored layer coating device 50, a guide roller 62 and a winding device 71 are provided. The manufactured colored optical fiber core wire 6 is guided by the guide roller 62 and wound around the winding device 71.

[0054] 5 is a schematic diagram showing a part of a manufacturing apparatus 10 used in the manufacturing method of an optical fiber ribbon according to this embodiment. The manufacturing apparatus 10 has a plurality of supply bobbins 81, guide rollers 82, a resin application device 83, an ultraviolet ray irradiation device 84, a guide roller 85, and a bobbin 86. In FIG. 5, the manufacturing apparatus 10 is an apparatus for manufacturing an optical fiber ribbon 8 from a colored optical fiber core 6.

[0055] A plurality of supply bobbins 81 are arranged side by side. The colored optical fiber 6 is wound around the supply bobbin 81. The colored optical fiber 6 wound around the supply bobbin 81 is guided by a guide roller 82 and transported to a resin application device 83.

[0056] The resin applicator 83 holds the ultraviolet curing resin of the ribbon layer 7. The ultraviolet curing resin of the ribbon layer 7 is applied to the plurality of colored optical fiber core wires 6 by the resin applicator 83.

[0057] An ultraviolet ray irradiation device 84 (fourth light source) is provided below the resin application device 83. The ultraviolet ray irradiation device 84 may be configured similarly to the ultraviolet ray irradiation devices 32, 42, 52. The plurality of colored optical fiber core wires 6 coated with the ultraviolet curable resin of the ribbon layer 7 enter the ultraviolet ray irradiation device 84, and the ultraviolet curable resin of the ribbon layer 7 is irradiated with ultraviolet rays. As a result, the ultraviolet curable resin of the ribbon layer 7 is cured, and the ribbon layer 7 is formed. The plurality of colored optical fiber core wires 6 are covered and connected by the ribbon layer 7, thereby forming an optical fiber ribbon 8.

[0058] 6 is a flow chart of a method for manufacturing an optical fiber ribbon 8 according to this embodiment. First, the optical fiber preform BM is placed in the manufacturing apparatus 10 (step S101).

[0059] Next, the heater 21 provided in the heating device 20 heats the optical fiber preform BM, and drawing of the bare optical fiber 2 starts (step S102).

[0060] The primary layer coating device 30 applies an ultraviolet-curable resin for the primary layer 3 around the drawn bare optical fiber 2, and irradiates the ultraviolet-curable resin for the primary layer 3 with ultraviolet light to form the primary layer 3 (step S103).

[0061] Next, the secondary layer coating device 40 applies an ultraviolet-curable resin of the secondary layer 4 around the primary layer 3, and irradiates the ultraviolet-curable resin of the secondary layer 4 with ultraviolet light to form the secondary layer 4 (step S104). This results in the optical fiber 1. The manufactured optical fiber 1 is wound up by a winding device 70.

[0062] Next, the colored layer coating device 50 applies an ultraviolet-curable resin for the colored layer 5 around the optical fiber 1, and irradiates the ultraviolet-curable resin for the colored layer 5 with ultraviolet light to form the colored layer 5 (step S105). This results in the production of the colored optical fiber 6. The manufactured colored optical fiber 6 is wound up by the winding device 71.

[0063] Next, the manufacturing apparatus 10 applies an ultraviolet-curable resin of the ribbon layer 7 to the plurality of colored optical fiber cores 6, and irradiates the ultraviolet-curable resin of the ribbon layer 7 with ultraviolet light to form the ribbon layer 7 (step S106). As a result, the optical fiber ribbon 8 is obtained.

[0064] It is not always necessary to irradiate the primary layer 3 with ultraviolet light in the step (step S103) of forming the primary layer 3. In this case, the primary layer 3 can be cured in the step (step S104) of forming the secondary layer 4.

[0065] According to this embodiment, it is possible to improve the separation performance of the optical fiber ribbon 8. The effects of this embodiment will be described in detail below in comparison with the prior art.

[0066] A technique is known in which the primary layer 3 covering the bare optical fiber 2, the secondary layer 4 covering the primary layer 3, and the colored layer 5 covering the secondary layer 4 in the optical fiber strand 1 or colored optical fiber core 6 are each formed from an ultraviolet curable resin. Also known is a technique in which a plurality of colored optical fiber cores 6 are covered with a ribbon layer 7 to form an optical fiber ribbon 8.

[0067] Usually, when the optical fiber ribbon 8 is installed, the colored optical fiber core wires 6 are taken out from the optical fiber ribbon 8. For this reason, it is preferable that the colored optical fiber core wires 6 can be easily taken out from the optical fiber ribbon 8, that is, the optical fiber ribbon 8 has good single-core separation properties. As a means for improving the single-core separation properties of the optical fiber ribbon 8, it can be considered to set the surface conversion rate of the colored layer 5 of the colored optical fiber core wires 6 to be high.

[0068] However, in the step of forming the colored layer 5, the temperature of the optical fiber 1 to which the ultraviolet-curable resin of the colored layer 5 is applied is lowered from the temperature at the time of manufacture to room temperature. On the other hand, in the step of forming the primary layer 3, the bare optical fiber 2 drawn out by melting the optical fiber preform BM is at a higher temperature than room temperature. Also, in the step of forming the secondary layer 4, the primary layer 3 covers the high-temperature bare optical fiber 2 and is heated by the curing heat of the ultraviolet-curable resin of the primary layer 3, so that it is at a higher temperature than room temperature. Therefore, the curing temperature and surface conversion rate of the colored layer 5 are lower than those of the primary layer 3 and the secondary layer 4.

[0069] In addition, depending on the manufacturing conditions of the optical fiber colored core 6, the surface conversion rate of the colored layer 5 may not be sufficiently high. For example, the ultraviolet light of a mercury lamp contains infrared light, while the ultraviolet light of a UV-LED does not contain infrared light. For this reason, when the light source of ultraviolet light irradiation is a UV-LED, the curing temperature and surface conversion rate of the colored layer 5 are lowered. In addition, when a UV-LED that irradiates ultraviolet light with a wavelength of 300 nm or more is used, the wavelength in the short wavelength region that is important in the surface conversion rate of the colored layer 5 is reduced compared to the ultraviolet light of a mercury lamp. Therefore, when the light source of ultraviolet light irradiation in the process of forming the colored layer 5 is a UV-LED, the surface conversion rate of the colored layer 5 is lowered.

[0070] Techniques for increasing the surface conversion rate of the colored layer 5 are described in WO 2016 / 017060, JP 2021-178741 A, JP 2018-177630 A, WO 2015 / 199199 A, WO 2016 / 072064 A, JP 2015-212222 A, and WO 2016 / 028668 A. However, even with these techniques, the surface conversion rate of the colored layer 5 cannot be sufficiently increased, and it may be difficult to obtain an optical fiber ribbon 8 having good single-core separation properties.

[0071] In this embodiment, by increasing the conversion rate of the portion of the ribbon layer 7 that contacts the colored layer 5, the adhesive force between the colored layer 5 and the ribbon layer 7 is reduced. In addition, by increasing the breaking elongation of the ribbon layer 7, when the colored optical fiber core wire 6 is taken out from the optical fiber ribbon 8, the ribbon layer 7 is less likely to remain on the surface of the colored optical fiber core wire 6, and the ribbon layer 7 can be easily removed. This can improve the single-core separation property of the optical fiber ribbon. In this embodiment, the conversion rate of the ribbon layer 7 of the portion of the ribbon layer 7 that contacts the colored layer 5 is 83.7% or more, and the breaking elongation of the ribbon layer 7 is 9.7% or more. Therefore, according to this embodiment, the single-core separation property of the optical fiber ribbon 8 can be improved.

[0072] Furthermore, compared to mercury lamps, UV-LEDs have the advantages of a longer lifespan, lower maintenance costs, etc. This makes it possible to significantly reduce the manufacturing cost of the optical fiber ribbon 8. According to this embodiment, even when the ultraviolet light source in the step of forming the colored layer 5 is a UV-LED, it is possible to improve the single-core separation property of the optical fiber ribbon 8.

[0073] Furthermore, the deterioration of the surface conversion rate of the colored layer 5 is not limited to the case where the ultraviolet light source is a UV-LED. For example, the surface conversion rate of the colored layer 5 may deteriorate when the manufacturing speed of the colored optical fiber core 6 is high, when the illuminance or dose of ultraviolet light is low, or when the oxygen concentration is high in the process of forming the colored layer 5. According to the present invention, even in such cases, it is possible to improve the single-core separation property of the optical fiber ribbon 8.

[0074] In this embodiment, the optical fiber ribbon 8 may have a bind layer that covers the ribbon layer 7. In this case, the adhesion between the ribbon layer 7 and the bind layer can be improved by lowering the surface conversion rate of the ribbon layer 7. Even in this case, the single-core separation property of the optical fiber ribbon 8 can be improved by setting the conversion rate of the portion of the ribbon layer 7 that contacts the colored layer 5 to 83.7% or more and the breaking elongation of the ribbon layer 7 to 9.7% or more.

[0075] Hereinafter, the measurement results of the optical fiber ribbon 8 according to the embodiment of the present invention will be described.

[0076] [Table 1]

[0077] Table 1 shows the conversion rate (%) of the portion of the ribbon layer in contact with the colored layer, the breaking elongation (%) of the ribbon layer, the breaking elongation (%) of the sheet-like cured product, and the evaluation of the separation property of the optical fiber ribbon.

[0078] In the examples and comparative examples, the ultraviolet curing resin of the ribbon layer was any one of Resin A to Resin I. The ultraviolet curing resin of the colored layer was cured by irradiation with ultraviolet light having a wavelength of 395 nm using a UV-LED as a light source. In the examples and comparative examples, the surface conversion rate of the colored layer was 85% or more and 92% or less. In the examples and comparative examples, the surface conversion rate of the colored layer was measured by a microscopic ATR (Attenuated Total Reflection) method of Fourier Transform Infrared (FT-IR) spectroscopy. The surface conversion rate of the colored layer was 1500 cm -1 Based on the peak area around 1407 cm before and after UV curing of the UV-curable resin in the colored layer, -1 In the examples and comparative examples, the ultraviolet-curable resin of the ribbon layer was cured by ultraviolet irradiation using a mercury lamp or a UV-LED, or both a mercury lamp and a UV-LED as a light source.

[0079] In the examples and comparative examples, a ribbon layer was obtained from the optical fiber ribbon by scraping off the ribbon layer with an unused single blade. A sheet-shaped cured product was also obtained by the following method. Using a spin coater, a film of the UV-curable resin of the ribbon layer was formed on a glass plate to a thickness of 40 μm or more and 60 μm or less. The film of the UV-curable resin of the ribbon layer was irradiated with UV rays from a mercury lamp as a light source. The UV-curable resin of the ribbon layer was sufficiently cured by the UV rays to obtain a sheet-shaped cured product. The mercury lamp was used for an illuminance of 1000 mW / cm. 2 , irradiation amount 1000mJ / cm 2 Illuminance measurements were performed using UV-351 from Oak Manufacturing Co., Ltd. Note that "sufficiently curing" a resin means that it has cured to a Young's modulus of 90% or more of the maximum Young's modulus that the resin can exhibit.

[0080] In the examples and comparative examples, the conversion rate of the ribbon layer was measured by the microscopic ATR method of Fourier transform infrared spectroscopy. The conversion rate of the ribbon layer was measured at 1500 cm -1 Based on the peak area around 810 cm before and after UV curing of the UV-curable resin in the ribbon layer, -1 This was determined from the decrease in height of the peak in the vicinity.

[0081] In the examples and comparative examples, the breaking elongation of the ribbon layer and the sheet-shaped cured product was measured by the following method. The ribbon layer and the sheet-shaped cured product were conditioned at constant temperature and humidity (temperature 23°C, relative humidity 50%) to obtain a sample piece with a length of 25 mm. The sample piece was elongated at a tensile speed of 50 mm / min in an atmosphere of constant temperature and humidity (temperature 23°C, relative humidity 50%), and the breaking elongation was measured from the elongation rate at break. The breaking elongation was measured four or more times for each example and comparative example, and the highest measured value was adopted as the breaking elongation listed in Table 1. The cross-sectional area of ​​the sample piece was measured using a microscope.

[0082] The breaking elongation of the ribbon layer of the optical fiber ribbon may vary depending on the manufacturing conditions of the optical fiber ribbon. The breaking elongation of the sheet-shaped cured material may be an index of the maximum breaking elongation that the UV-curable resin of the ribbon layer can have. Therefore, the breaking elongation of the sheet-shaped cured material is generally greater than that of the ribbon layer.

[0083] "Evaluation 1" in Table 1 indicates whether the optical fiber ribbon has good single-core separation ability. The single-core separation ability of the optical fiber ribbon was evaluated by the following method. First, a crack was made in the tape layer at the end of the optical fiber ribbon without using a special tool. Next, the ribbon layer was removed to separate the colored optical fiber from the optical fiber ribbon. If the separated colored optical fiber does not experience peeling of the colored layer or breakage of the colored optical fiber, and the cuticle of the ribbon layer does not adhere to the surface of the colored layer, Evaluation 1 is judged to be good (OK). If the separated colored optical fiber experiences peeling or breakage of the colored layer, or the cuticle of the ribbon layer adheres to the surface of the colored layer, Evaluation 1 is judged to be poor (NG).

[0084] In Example 1, the UV-curable resin of the ribbon layer was Resin A. The conversion rate of the ribbon layer was 83.7%. The breaking elongation of the ribbon layer was 41.0%. The breaking elongation of the sheet-shaped cured product was 60.5%. When the colored optical fiber was separated from the optical fiber ribbon, peeling of the colored layer and breakage of the colored optical fiber did not occur. Furthermore, the skin of the ribbon layer did not adhere to the surface of the colored layer. Therefore, the evaluation 1 was good (OK).

[0085] In Example 2, the UV-curable resin of the ribbon layer was Resin B. The conversion rate of the ribbon layer was 87.4%. The breaking elongation of the ribbon layer was 18.2%. The breaking elongation of the sheet-shaped cured product was 64.7%. When the colored optical fiber was separated from the optical fiber ribbon, peeling of the colored layer and breakage of the colored optical fiber did not occur. Furthermore, the skin of the ribbon layer did not adhere to the surface of the colored layer. Therefore, the evaluation 1 was good (OK).

[0086] In Example 3, the UV-curable resin of the ribbon layer was resin C. The conversion rate of the ribbon layer was 84.5%. The breaking elongation of the ribbon layer was 20.5%. The breaking elongation of the sheet-shaped cured product was 65.0%. When the colored optical fiber was separated from the optical fiber ribbon, peeling of the colored layer and breakage of the colored optical fiber did not occur. Furthermore, the skin of the ribbon layer did not adhere to the surface of the colored layer. Therefore, the evaluation 1 was good (OK).

[0087] In Example 4, the UV-curable resin of the ribbon layer was Resin D. The conversion rate of the ribbon layer was 91.0%. The breaking elongation of the ribbon layer was 54.0%. The breaking elongation of the sheet-shaped cured product was 54.3%. When the colored optical fiber core was separated from the optical fiber ribbon, peeling of the colored layer and breakage of the colored optical fiber core did not occur. Furthermore, the skin of the ribbon layer did not adhere to the surface of the colored layer. Therefore, the evaluation 1 was good (OK).

[0088] In Example 5, the UV-curable resin of the ribbon layer was Resin E. The conversion rate of the ribbon layer was 94.1%. The breaking elongation of the ribbon layer was 15.8%. The breaking elongation of the sheet-shaped cured product was 38.7%. When the colored optical fiber was separated from the optical fiber ribbon, peeling of the colored layer and breakage of the colored optical fiber did not occur. Furthermore, the skin of the ribbon layer did not adhere to the surface of the colored layer. Therefore, the evaluation 1 was good (OK).

[0089] In Example 6, the UV-curable resin of the ribbon layer was Resin F. The conversion rate of the ribbon layer was 95.0%. The breaking elongation of the ribbon layer was 9.4%. The breaking elongation of the sheet-shaped cured product was 23.6%. When the colored optical fiber was separated from the optical fiber ribbon, peeling of the colored layer and breakage of the colored optical fiber did not occur. Furthermore, the skin of the ribbon layer did not adhere to the surface of the colored layer. Therefore, the evaluation 1 was good (OK).

[0090] In Example 7, the UV-curable resin of the ribbon layer was resin G. The conversion rate of the ribbon layer was 90.2%. The breaking elongation of the ribbon layer was 13.3%. The breaking elongation of the sheet-shaped cured product was 33.8%. When the colored optical fiber core was separated from the optical fiber ribbon, peeling of the colored layer and breakage of the colored optical fiber core did not occur. Furthermore, no cuticle of the ribbon layer remained on the surface of the colored layer. Therefore, the evaluation 1 was good (OK).

[0091] In Comparative Example 1, the UV-curable resin of the ribbon layer was Resin H. The conversion rate of the ribbon layer was 81.8%. The breaking elongation of the ribbon layer was 41.1%. The breaking elongation of the sheet-shaped cured product was 60.5%. When the colored optical fiber core was separated from the optical fiber ribbon, peeling of the colored layer occurred, or the skin of the ribbon layer adhered to the surface of the colored layer. Therefore, the evaluation 1 was poor (NG).

[0092] In Comparative Example 2, the UV-curable resin of the ribbon layer was Resin I. The conversion rate of the ribbon layer was 94.3%. The breaking elongation of the ribbon layer was 5.4%. The breaking elongation of the sheet-shaped cured product was 8.4%. When the colored optical fiber core was separated from the optical fiber ribbon, peeling of the colored layer occurred, or the skin of the ribbon layer adhered to the surface of the colored layer. Therefore, the evaluation 1 was poor (NG).

[0093] In the examples and comparative examples, the number of fibers in the optical fiber ribbon is 4. However, even when the number of fibers in the optical fiber ribbon is, for example, 2, 8, 12, or 24, the same measurement results as those in Table 1 are obtained.

[0094] In addition, when the colored layer of the colored core wire used in the examples and comparative examples is formed using a mercury lamp as a light source instead of a UV-LED, the surface conversion rate of the colored layer is 92% or more and 96% or less. The surface conversion rate of the colored layer can vary depending on the manufacturing conditions of the optical fiber colored core wire, the composition of the ultraviolet curing resin of the colored layer, and the color of the colored layer. In addition, the colored layer in the examples and comparative examples is blue or brown. In general, the colored layer formed by ultraviolet irradiation from a mercury lamp has a higher surface conversion rate than the colored layer formed by ultraviolet irradiation from a UV-LED. For each of Examples 1 to 7 and Comparative Examples 1 to 2, the single-core separation property of the optical fiber ribbon when the colored layer is formed by ultraviolet irradiation from a mercury lamp was evaluated. In Examples 1 to 7 and Comparative Example 1, Evaluation 1 was good (OK), and in Comparative Example 2, Evaluation 1 was poor (NG).

[0095] It should be noted that even when the wavelength of the UV-LED in the examples and comparative examples is not 395 nm, the same measurement results as those in Table 1 are obtained. For example, when the wavelength of the UV-LED is 275 nm, 365 nm, or 385 nm, the same measurement results as those in Table 1 are obtained.

[0096] The ribbon layer preferably has a conversion rate of 83.7% or more in the portion in contact with the colored layer, and the ribbon layer preferably has a breaking elongation of 9.4% or more, thereby making it possible to provide an optical fiber ribbon with good single-core separation properties.

[0097] The present invention is not limited to the above-described embodiments and can be modified in various ways. For example, an example in which a part of the configuration of any of the embodiments is added to another embodiment, or an example in which a part of the configuration of another embodiment is replaced with another embodiment is also an embodiment of the present invention. Furthermore, with respect to parts not specifically described or illustrated in the embodiments, well-known or publicly known techniques in the relevant technical field can be appropriately applied. [Explanation of symbols]

[0098] 1. Optical fiber 2 Bare optical fiber 3 Primary Layer 4 Secondary Tier 5 Colored layer 6. Colored optical fiber 7 Ribbon Layer 8 Optical Fiber Ribbons

Claims

1. a plurality of colored optical fiber core wires including a bare optical fiber, a primary layer formed of a first ultraviolet-curable resin covering the bare optical fiber, a secondary layer formed of a second ultraviolet-curable resin covering the primary layer, and a colored layer formed of a third ultraviolet-curable resin covering the secondary layer; a ribbon layer formed of a fourth ultraviolet curing resin covering the plurality of colored optical fiber cores; The conversion rate of the portion of the ribbon layer in contact with the colored layer is 83.7% or more, An optical fiber ribbon, wherein the ribbon layer has a breaking elongation of 9.4% or more.

2. a plurality of colored optical fiber core wires including a bare optical fiber, a primary layer formed of a first ultraviolet-curable resin covering the bare optical fiber, and a secondary layer formed of a second ultraviolet-curable resin covering the primary layer; a ribbon layer formed of a fourth ultraviolet curing resin covering the plurality of colored optical fiber cores; the secondary layer is a colored layer that is colored, The conversion rate of the portion of the ribbon layer in contact with the colored layer is 83.7% or more, An optical fiber ribbon, wherein the ribbon layer has a breaking elongation of 9.4% or more.

3. 3. The optical fiber ribbon according to claim 1, wherein the surface conversion rate of the colored layer is 96.0% or less.

4. 3. The optical fiber ribbon according to claim 1, wherein the surface conversion rate of the colored layer is 92.0% or less.

5. 3. The optical fiber ribbon according to claim 1, wherein a conversion rate of the portion of the ribbon layer in contact with the colored layer is 95.0% or less.

6. 3. The optical fiber ribbon according to claim 1, wherein the ribbon layer has a breaking elongation of 65.0% or less.

7. 2. The optical fiber ribbon according to claim 1, wherein the third ultraviolet-curing resin is cured by ultraviolet light emitted by a light-emitting diode.

8. 3. The optical fiber ribbon according to claim 1, wherein the fourth ultraviolet-curing resin is cured by ultraviolet light emitted by a light-emitting diode.

9. 3. The optical fiber ribbon according to claim 2, wherein the second ultraviolet-curing resin is cured by ultraviolet light emitted by a light-emitting diode.

10. A step of drawing a bare optical fiber from an optical fiber preform; a step of applying a first ultraviolet curing resin for forming a primary layer around the bare optical fiber and irradiating the first ultraviolet curing resin with ultraviolet light from a first light source to form a primary layer; applying a second ultraviolet-curable resin to form a secondary layer around the primary layer, and irradiating the second ultraviolet-curable resin with ultraviolet light from a second light source to form a secondary layer; a step of applying a third ultraviolet curing resin to form a colored layer around the secondary layer, and irradiating the third ultraviolet curing resin with ultraviolet light from a third light source to form a colored layer; applying a fourth ultraviolet-curing resin to form a ribbon layer around the colored layer, and irradiating the fourth ultraviolet-curing resin with ultraviolet light from a fourth light source to form a ribbon layer; The conversion rate of the portion of the ribbon layer in contact with the colored layer is 83.7% or more, A method for manufacturing an optical fiber ribbon, wherein the ribbon layer has a breaking elongation of 9.4% or more.

11. 11. The method for manufacturing an optical fiber ribbon according to claim 10, wherein at least one of the first light source, the second light source, the third light source and the fourth light source is a light emitting diode.

12. The method for manufacturing an optical fiber ribbon according to claim 10, wherein the third ultraviolet-curing resin is cured by ultraviolet light emitted by a light-emitting diode.

13. The method for manufacturing an optical fiber ribbon according to claim 10, wherein the third light source includes a light emitting diode.

14. The method for manufacturing an optical fiber ribbon according to claim 10, wherein the fourth light source includes a light emitting diode.

15. The method for manufacturing an optical fiber ribbon according to claim 10, wherein the fourth ultraviolet-curing resin is cured by ultraviolet light emitted by a light-emitting diode.

16. A step of drawing a bare optical fiber from an optical fiber preform; a step of applying a first ultraviolet curing resin for forming a primary layer around the bare optical fiber and irradiating the first ultraviolet curing resin with ultraviolet light from a first light source to form a primary layer; applying a second ultraviolet-curable resin to form a secondary layer around the primary layer, and irradiating the second ultraviolet-curable resin with ultraviolet light from a second light source to form a colored secondary layer; and applying a fourth ultraviolet-curing resin to form a ribbon layer around the secondary layer, and irradiating the fourth ultraviolet-curing resin with ultraviolet light from a fourth light source to form a ribbon layer. The conversion rate of the portion of the ribbon layer in contact with the secondary layer is 83.7% or more; A method for manufacturing an optical fiber ribbon, wherein the ribbon layer has a breaking elongation of 9.4% or more.

17. 17. The method for manufacturing an optical fiber ribbon according to claim 16, wherein at least one of the first light source, the second light source and the fourth light source is a light emitting diode.

18. The method for manufacturing an optical fiber ribbon according to claim 16, wherein the second ultraviolet-curing resin is cured by ultraviolet light emitted by a light-emitting diode.

19. The method for manufacturing an optical fiber ribbon according to claim 16, wherein the second light source includes a light emitting diode.

20. The method for manufacturing an optical fiber ribbon according to claim 16, wherein the fourth light source includes a light emitting diode.

21. The method for manufacturing an optical fiber ribbon according to claim 16, wherein the fourth ultraviolet curing resin is cured by ultraviolet light emitted by a light emitting diode.

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