JPS61197449A - Production of core line of optical fiber - Google Patents

Abstract

PURPOSE:To produce a core line of optical fiber having small variability of outer diameter efficiently, by coating the circumference of optical fiber with an ultraviolet-curing resin, and irradiating the resin with ultraviolet rays after cooling it or while cooling so that it is cured. CONSTITUTION:The optical fiber 1 consisting of a core and a clad, being pulled at a constant speed in the arrow direction A is provided with the ultraviolet- curing resin 3 from the resin storage tank 6 through the die 4 and coated. Then, the resin is cooled with air by the cooling chamber 7 connected to a part below the die 2. A cooling gas to be fed to the cooling chamber 7 is fed from the blow inlet 8 shown by the arrow B while being controlled to a desired temperature and amount, and exhausted from the outlets 9 and 10 shown by the arrows C and D. The viscosity of the ultraviolet-curing resin 3 is raised by this cooling, drop of the resin 3 by its own weight is prevented. The resin is irradiated with ultraviolet rays by the ultraviolet lamp 4, and the resin 3 is cured. An ozone gas occurring during the curing is exhausted from the outlets 9 and 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing an optical fiber core in which an optical fiber is coated with an ultraviolet curable resin.

[Prior art]

Optical fibers used in optical fiber cables generally consist of a core and a cladding, or are coated with silicone resin, etc., and coated with nylon, etc., so-called optical fiber cores. It is something that can be done. Incidentally, in recent years, coated optical fibers coated with ultraviolet curable resin instead of nylon have also been manufactured. The method of coating with this ultraviolet curable resin is as shown in FIG. Thereafter, the applied ultraviolet curable resin 3 is irradiated and cured using an ultraviolet lamp 4 to obtain an optical fiber core 5. Incidentally, reference numeral 6 denotes a resin storage tank for supplying liquid ultraviolet curable resin 3 to the die 2.

In this conventional method, since the viscosity of the applied ultraviolet curable resin 3 is extremely low, it is hardened by its own weight from immediately after it is applied to the optical fiber 1 until it is cured by the ultraviolet lamp 4. It sags or drips, making it impossible to coat it with a uniform thickness. That is, there is a problem in that the outer diameter of the optical fiber varies greatly.

[Purpose of the invention]

In view of the above problems, it is an object of the present invention to provide a method for manufacturing an optical fiber coated with an ultraviolet curable resin without any variation in outer diameter.

[Structure of the invention]

In order to achieve the above object, the present invention provides a method for manufacturing a coated optical fiber having a coating made of an ultraviolet curable resin around an optical fiber, which comprises applying the ultraviolet curable resin around the optical fiber. It is characterized in that it is then cooled or irradiated with ultraviolet rays while being cooled to harden it.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the invention. As shown in this figure, in the manufacturing method of the present invention, a resin storage tank 6 supplies the optical fiber 1 consisting of a core and cladding, which is being pulled in the direction of arrow A at a constant speed by a pulling machine (not shown). The liquid ultraviolet curable resin 3 is applied through the die 2. After that, the dice 2
This is air-cooled by a cooling chamber 7 connected below.

The cooling gas to be passed through the cooling chamber 7 is supplied from an inlet 8 indicated by an arrow B while being controlled at a desired temperature and in a desired amount, and is supplied from an outlet 9 and an outlet 10 indicated by an arrow C1.
is discharged from. Of course, the inlet 8 and the outlet 9.
10, and the cooling gas may be circulated while being cooled through a suitable cooling device. The ultraviolet curable resin 3 coated on the optical fiber 1 in this way is transferred to the cooling chamber 7.
By cooling, the viscosity of the ultraviolet curable resin 3 is increased and the dripping of the ultraviolet curable resin 3 due to its own weight is prevented. Reference numeral 4 denotes an ultraviolet lamp provided in the cooling chamber 7, which irradiates the ultraviolet curing resin 3 with ultraviolet rays to harden it and obtain the optical fiber core 5. Incidentally, for example, ozone gas generated when the ultraviolet curable resin 3 is cured is discharged through the outlet 9.10 of the cooling chamber 7. Furthermore, the die 2 and the cooling chamber 7 are thermally insulated to prevent the ultraviolet curing resin 3 inside the die 2 from being cooled from the cooling chamber side. In the above, the optical fiber 1 consists of only a core and a cladding, but the optical fiber 1 consists of a core and a cladding coated with silicone resin, etc. The same applies to the case where the resin 3 is coated.

As described above, according to the present invention, by immediately cooling the ultraviolet curable resin applied to the optical fiber, the viscosity of the resin is increased, and the self-weight of the resin is increased until it is cured by the ultraviolet lamp. Prevent dripping. Therefore, the conventional problem that the outer diameter of the optical fiber varies can be solved. Furthermore, by cooling the resin immediately after coating, the viscosity of the ultraviolet curable resin at the time of coating with a die may be even lower. As a result, since the viscosity of the resin at the time of application is low, it is easy to apply the resin to the optical fiber, thereby making the optical core of the ultraviolet curable resin. In an optical fiber coated wire having a coating made of resin, it is possible to efficiently manufacture an optical fiber coated wire with little variation in outer diameter.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the method for producing a coated optical fiber according to the present invention, and FIG. 2 is a schematic diagram showing a conventional method for producing a coated optical fiber. 1 ----One optical fiber 2-Curved die 3-・
-Ultraviolet curable resin 4 -1111 ultraviolet lamp 5
−・− Optical fiber core wire? --- Cooling chamber patent applicant Furukawa Electric Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] In a method for manufacturing an optical fiber coated wire having a coating made of an ultraviolet curable resin around an optical fiber, the ultraviolet curable resin is applied around the optical fiber and then cooled or while being cooled. A method for producing an optical fiber core, the method comprising curing it by irradiating it with ultraviolet rays.