Abstract: A resin coating device for coating a surface of a glass fiber, includes: a point having a point hole; a die disposed directly below the point and including a first alignment portion, a second alignment portion, and a first die hole; and a first resin supply path. The second alignment portion is disposed below the first alignment portion. The first alignment portion includes a first diameter-reduced portion, and a first land portion disposed, connected to the first diameter-reduced portion, and having a constant diameter in the traveling direction. The second alignment portion includes a second diameter-reduced portion, and a second land portion, connected to the second diameter-reduced portion, and having a constant diameter in the traveling direction. The first diameter-reduced portion, the first land portion, the second diameter-reduced portion, and the second land portion are each a part of the first die hole.

Abstract: A coating device includes: a fiber passage through which a glass fiber passes downward in a vertical direction; a first flow path which is a flow path allowing a primary resin to flow toward the fiber passage and includes a first branch path horizontally dividing the primary resin moving in a horizontal direction; a first temperature controller which is disposed along the first flow path and controls a temperature of the first flow path; a second flow path which is a flow path allowing a secondary resin to flow toward the fiber passage, includes a second branch path horizontally dividing the secondary resin moving in the horizontal direction, and is located below the first flow path; and a second temperature controller which is disposed along the second flow path and controls a temperature of the second flow path.

Abstract: The optical fiber manufacturing method includes: a drawing step of drawing a glass fiber from an optical fiber base material with a melted tip; a passing step of passing the glass fiber through a fiber passage formed in a die; and a resin coating step of forming a resin layer on the outer periphery of the glass fiber by supplying a resin to the fiber passage through a flow path communicating with the fiber passage formed in the die. In the resin coating step, a temperature of the resin is controlled so that a supply pressure of the resin to the fiber passage becomes a value in a predetermined range.

Abstract: When a glass fiber and an inner fiber coating layer are to be attached to a connector by removing an outer fiber coating layer while leaving the inner fiber coating layer as it is, a collective coating and the outer fiber coating layer can be removed at a stretch so that the inner fiber coating layer can easily and satisfactorily be exposed. In the ultraviolet curable resin coating layer of a coated optical fiber 17 of an optical fiber ribbon 11 for wiring of equipment, the inner fiber coating layer 15 has a Young's modulus of 600 MPa to 1000 MPa, and the outer fiber coating layer 16 has a Young's modulus of 10 MPa to 300 MPa. The material of the outer fiber coating layer 16 is made by mixing 100 weight parts of base resin, 1-30 weight parts of silicone-based additive, and 0.5 to 40 weight parts of long chain fatty acid ester compound, wherein the base resin is a material made of a urethane metha acrylate oligomer, a mono-functional or multi-functional reactive dilution monomer, and an optical initiator.

Abstract: When a glass fiber and an inner fiber coating layer are to be attached to a connector by removing an outer fiber coating layer while leaving the inner fiber coating layer as it is, a collective coating and the outer fiber coating layer can be removed at a stretch so that the inner fiber coating layer can easily and satisfactorily be exposed. In the ultraviolet curable resin coating layer of a coated optical fiber 17 of an optical fiber ribbon 11 for wiring of equipment, the inner fiber coating layer 15 has a Young's modulus of 600 MPa to 1000 MPa, and the outer fiber coating layer 16 has a Young's modulus of 10 MPa to 300 MPa. The material of the outer fiber coating layer 16 is made by mixing 100 weight parts of base resin, 1-30 weight parts of silicone-based additive, and 0.5 to 40 weight parts of long chain fatty acid ester compound, wherein the base resin is a material made of a urethane metha acrylate oligomer, a mono-functional or multi-functional reactive dilution monomer, and an optical initiator.

Abstract: A molding die 1 is constituted by an upper die 1a and a lower die 1b which are made of a material transparent to an ultraviolet light, and has a cavity 3 constituted by grooves 2c, 2d, whereas a resin injection gate 4 and a resin exit gate 7 are provided so as to communicate with the cavity 3. A junction of an optical fiber 10 is inserted into the cavity 3. A UV-curable resin is injected into the cavity 3 surrounding an exposing portion of the glass optical fiber 11 from the resin injection gate 4 positioned at one of coating ends of the optical fiber 10, whereas a part thereof is discharged from the resin exit gate 7 positioned at the other coating end. The ultraviolet light is emitted through the lower die 1b so as to cure the resin, thereby forming a reinforcement resin coating. As a consequence, bubbles can be prevented from occurring due to the residual air within the reinforcement resin coating in the junction of the optical fiber 10.

Abstract: In a method for molding an optical fiber fusion spliced portion, a mold coating is formed on a bare fiber portion of a fusion spliced portion of the optical fibers, using a resin compound having the characteristics where in a cured state, the tensile elongation is 70% or more and the tensile strength is 20MPa or more.

Abstract: In a method for molding an optical fiber fusion spliced portion, a mold coating is formed on a bare fiber portion of a fusion spliced portion of the optical fibers, using a resin compound having the characteristics where in a cured state, the tensile elongation is 70% or more and the tensile strength is 20MPa or more.

Abstract: In an optical fiber coating method comprising the steps of; applying an injecting first coating resin to the outer periphery of the optical fiber while inserting the optical fiber through a first die hole provided in a first coating die; and applying an injected second coating resin onto the first coating resin while inserting the optical fiber through a second die hole provided in a second coating die.

Abstract: In an optical fiber coating method comprising the steps of; applying an injecting first coating resin to the outer periphery of the optical fiber while inserting the optical fiber through a first die hole provided in a first coating die; and applying an injected second coating resin onto the first coating resin while inserting the optical fiber through a second die hole provided in a second coating die.

Abstract: A molding die 1 is constituted by an upper die 1a and a lower die 1b which are made of a material transparent to an ultraviolet light, and has a cavity 3 constituted by grooves 2c, 2d, whereas a resin injection gate 4 and a resin exit gate 7 are provided so as to communicate with the cavity 3. A junction of an optical fiber 10 is inserted into the cavity 3. A UV-curable resin is injected into the cavity 3 surrounding an exposing portion of the glass optical fiber 11 from the resin injection gate 4 positioned at one of coating ends of the optical fiber 10, whereas a part thereof is discharged from the resin exit gate 7 positioned at the other coating end. The ultraviolet light is emitted through the lower die 1b so as to cure the resin, thereby forming a reinforcement resin coating. As a consequence, bubbles can be prevented from occurring due to the residual air within the reinforcement resin coating in the junction of the optical fiber 10.

Abstract: In a resin coating applicator, a holder 14 is fixed on a base 15 fitted to a drawing machine, and in the holder 14, hot water can be circulated from an inlet 18. The inner circumferential surface of the holder 14 is formed into a tapered shape so that the outer circumferential surface of a cup-like member 4 of a cartridge type coating sub-assembly 1 is fitted to the holder 14. The respective outer circumferential surfaces of a nipple 2 and a coating die 3 are cylindrical so as to be fitted to the inner circumferential surfaces of an inner cylindrical member 6, and they are positioned by a step portion. Further, they are pressed from the upper and lower sides by the bottom portion of the cup-like member 4 and a lid member 5. The lid member 5 is fastened to the cup-like member 4 integrally by a thread.

Abstract: The present invention relates to an optical fiber coating method and an apparatus therefor which can form high quality coating layer on an optical fiber (12) by preventing non-concentricity of a coating resin (14) applied on the optical fiber (12) and admixing of bubble.

Abstract: A coated optical fiber comprising a light-transmitting fiber and a resin coating layer disposed on the outer periphery of the light-transmitting fiber is formed, an external flaw is imparted to the surface of the resin coating layer while running the coated optical fiber, and then the coated optical fiber is subjected to the measurement of a tensile breaking strength thereof. At this time, the fiber having a strength retention ratio R.sub.S =S.sub.A /S.sub.0 of 0.98 or more, wherein S.sub.A is the median value of the tensile breaking strength after the provision of the external flaw, and S.sub.0 is the median value of the tensile breaking strength before the provision of the external flaw, is selected as a non-defective product.

Abstract: A coated optical fiber comprising a light-transmitting fiber and a resin coating layer disposed on the outer periphery of the light-transmitting fiber is formed, an external flaw is imparted to the surface of the resin coating layer while running the coated optical fiber, and then the coated optical fiber is subjected to the measurement of a tensile breaking strength thereof. At this time, the fiber having a strength retention ratio R.sub.S =S.sub.A /S.sub.0 of 0.98 or more, wherein S.sub.A is the median value of the tensile breaking strength after the provision of the external flaw, and S.sub.0 is the median value of the tensile breaking strength before the provision of the external flaw, is selected as a non-defective product.

Abstract: A physical property evaluation method for optical fiber coating which is easy in producing a sample and high in accuracy and which is capable of measuring the shear modulus or tensile modulus with high accuracy, and a coated optical fiber with good lateral pressure characteristics using this evaluation method.

Abstract: A light transmitting optical fiber having at least one coating layer of an ultraviolet curing resin on an outer surface of the fiber, in which the ultraviolet curing resin used in an outermost layer has a Young's modulus of at least 100 kg/mm.sup.2 and an elongation of at least 30%.