JPS61183611A - Covering method for optical fiber - Google Patents

Abstract

PURPOSE:To cover an optical fiber by increasing a type winding sped without damaging the surface of a tape, by covering the optical fiber by heating at least two pieces of tapes whose coefficients of thermal expansion are different from each other. CONSTITUTION:An adhesive layer 2-3 having a thermal or chemical adhesive capacity is provided on an internal tape layer 2-2 side of a covering tape 2, coefficients of thermal expansion of an external tape layer 2-1 and the internal tape 2-2 are made different from each other, and also the width is made wider than the outside periphery of an optical fiber 1. Also, the optical fiber 1 and the covering tape 2 are set to a parallel state in the longitudinal direction, the surface of the external tape 2-1 is heated, and a warp is generated in the direction vertical to the longitudinal direction of the tape 2, by which the tape 2 is wound continuously to the outside periphery of the longitudinal direction of the optical fiber 1, and the tape 2 is stuck in a superposed part 5 of the tape 2 by the adhesive layer 2-3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method of vertically covering the outer periphery of a Hikari 7 Eyeper with a tape.

(Prior art) As a method of coating an optical fiber with a tape-shaped material,
There are two methods: one is to wind the tape horizontally, and the other is to roll the tape vertically using a roll former. However, it is difficult to increase the manufacturing speed of the former, and the latter is a Whirlformer.
There was a problem in that the tape was easily scratched due to friction and its quality deteriorated.

(Problems to be Solved by the Invention) Optical fibers can be coated without damaging the surface of the tape by forcibly bending it as in conventional vertical splicing, and with a faster tape winding speed than before. It's about doing.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention heats at least two tapes having different coefficients of thermal expansion and wraps them around the outer periphery of an optical fiber in the longitudinal direction of the optical fiber. Continuously attach vertically.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a cross-sectional view of one embodiment of a coated optical fiber manufactured by the coating method of the present invention, in which 1 is an optical fiber;
2 is a covering tape, 2-1 is an outer tape layer, 2-2 is an inner tape layer, 2-8 is an adhesive layer, and 5 is a tape overlapping portion.

2 is a perspective view of the optical fiber shown in FIG. 1. FIG.

FIG. 8 is a manufacturing process diagram according to the optical fiber coating method of the present invention, in which 8 is an optical fiber core, 4 is a tape bobbin, and 6 is a manufacturing process diagram.
is the heating section.

The present invention is a method of vertically covering the outer periphery of a Hikari 7 Eyeper with a tape-like material, and in this embodiment, two tapes with different coefficients of thermal expansion provided with an adhesive layer 2-8 are integrated. It takes advantage of the effect that the tape warps into a cylindrical shape by applying heat.

In FIG. 8, at the tape supply section where the optical fiber and the coated tape are supplied, the optical fiber and the coated tape are parallel to each other in the longitudinal direction. Thereafter, a heating section 6. the device is not specifically shown. So 1. When the surface of the outer tape 2-1 is heated, the outer tape layer 2-1 becomes more intense than the inner tape layer 2-1.
Since the coefficient of thermal expansion is greater than 2, the covering tape curls inward to cover the optical fiber 1. Also, at this time, the coating tape is provided with an adhesive layer 2-8, and when the adhesive layer 2-8 is melted by this heating and the coating tape 2 completely wraps around the optical fiber, the coating tape overlapping portion 6 The tape can now be attached.

Thereafter, by cooling, the optical fiber core Sa can be easily manufactured.

In a first embodiment of the covering tape material, the inner tape layer is made of polyimide and the outer tape layer is made of polyamide. In the second embodiment, the inner tape layer is made of polyimide and the outer tape layer is made of FEP (in tetrafluoroethylene). A combination of materials with large differences in coefficient of thermal expansion, such as Teflon (a copolymer of safluoropropylene), is required. Furthermore, by using a metal-deposited outer tape layer, the difference in thermal expansion coefficient can be increased, and the moisture permeability effect can also be improved. Furthermore, if you use heat shrink tape for the internal tape layer,
It is also possible to improve the curling effect of the coated tape.

As another example, polyimide (coefficient of thermal expansion Wks X 10/''C) was used for the inner tape layer, polyamide (coefficient of thermal expansion 108 IO/''C) was used for the outer tape layer, and the heating temperature was set to 200°C. The transmission loss of the obtained optical fiber was the same as that of the glass fiber itself, and there was no increase in loss due to manufacturing. Further, the optical fiber core wire was subjected to a heat cycle test at -40°C to 80°C, but even after 10 cycles, there was almost no increase in loss and the optical fiber did not break.

Since the optical fiber coating method of the present invention is characterized in that the coating tape curls in a direction perpendicular to the longitudinal direction of the fiber, it is necessary to use a material that does not warp or shrink in the longitudinal direction as the coating tape material. Moreover, applying tension in the longitudinal direction of the covering tape allows more effective covering.

It goes without saying that the adhesive effect of the tape overlapping portion 5 of the covering tape can be increased by applying pressure with a four-layer or the like at the tape overlapping portion 5 of the covering tape.

Furthermore, the optical fiber coating method of the present invention can be used not only for optical fiber core wires but also for optical cable jackets or metal core wires. It's okay.

・Furthermore, the adhesive layer 2-8 of the covering tape 2 can be applied to the entire surface or part of one or both sides of the covering tape depending on the adhesion situation, and the adhesive material can be applied to the tape overlapping part 5 on the production line. The adhesive layer 2-8 may not be provided on the covering tape if it can be supplied in the middle.

(Effects of the Invention) As explained above, the optical fiber coating method according to the present invention is a method of coating an optical fiber by applying heat to an integrated product of two tapes having different coefficients of thermal expansion. This method has the advantage that it does not damage the surface of the tape by forcibly bending it as in conventional longitudinal splicing, and the tape can be wound at a faster speed than before to coat the optical fiber.

Furthermore, since the tape is attached vertically, it is possible to coat even small diameter materials at low cost.

Furthermore, since optical fibers of the same length are fabricated by applying tape vertically, the length of the overlap can be made shorter than when wrapping with tape, which has the effect of increasing the reliability of the bonded portion. Furthermore, if a flame retardant material such as polyimide or a metal layer is used for the outer tape layer 2-1 of the covering tape, a coated optical fiber that is difficult to burn can be produced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one embodiment of the optical fiber coated wire manufactured by the coating method of the present invention. FIG. 2 is a perspective view of the optical fiber coated wire shown in FIG. 1, and FIG. It is a manufacturing process diagram by a fiber coating method. 1...Optical fiber 2...Coated tape! -1
--- External tape layer 2-2 --- Internal tape layer 2-
8... Adhesive layer 8... Optical 7 Ibara core wire 4.
・Tape bobbin 6 ・Tape overlapping part 6 ・
・Heating part

Claims (1)

[Claims] 1. A covering tape that has thermal or chemical adhesion ability on at least one side and has a width wider than the outer periphery of an optical fiber and that integrates at least two tape layers with different coefficients of thermal expansion. By heating the tape to cause warpage in a direction perpendicular to the longitudinal direction, the tape is continuously wound around the outer circumference of the optical fiber in the longitudinal direction, and the thermal or chemical bonding ability is improved. An optical fiber coating method characterized in that the optical fiber is coated with the tape longitudinally by adhering the overlapped portions of the tape. 2. The optical fiber coating method according to claim 1, wherein the coating tape uses a heat shrink tape for at least one tape layer.