JPS6111712A - Production of frp-coated optical fiber - Google Patents

Abstract

PURPOSE:To center satisfactorily an optical fiber core regardless of the various diameters of the optical fiber by providing a centering die just before a mold, coating the outside circumferential surface of the optical fiber core body with a fiber-reinforced resin and curing the fiber-reinforced resin. CONSTITUTION:The centering die M is provided just before a mold 17 and the optical fiber core body 1 is introduced into the die M and after the core body is centered by said die, the core body is conducted to the mold 17. On the other hand, the fibers 12 let off from fiber creels 11 are dipped into an uncured resin 15 and are impregnated with the resin and thereafter the fibers are introduced into the mold 17 while the fibers are guided by the outside circumferential surface of the die M from a guide roller 16. The outside circumferential surface of the body 1 is uniformly coated with the fibers 12 impregnated with the resin and the resin is cured. The optical fiber core body is thus surely centered even in the case of manufacturing the slender optical fiber. The offcentering of the core body and the deviation of the FRP layer coating the core body are obviated and therefore the optical transmission loss is decreased.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides an optical fiber core made of FRP (#h fiber reinforced resin).
The present invention relates to an advantageous method for producing optical fibers coated with.

[Prior art]

Optical fiber consists of a core and a cladding made of two types of glass or plastic with different refractive indexes (core and sheath), and a protective layer is provided on the outer surface of the core to transmit light. Since it has the property of being able to send from one end to the other without scattering, communication technology that utilizes this is being put into practical use.

In the protective layer, silicone or acrylic resin is used as a soft layer, and nylon, acrylic resin, thermosetting FRP, or the like is used as a hard layer. Further, in order to stabilize the quality of the optical fiber, it is desirable that the core and the protective layer are not eccentric from each other.

Conventionally, various centering methods have been used to prevent eccentricity of the core. However, with these methods, centering of the core is not sufficient, and a layer of only resin tends to form between the core and the protective layer, and this resin-only part has a large curing shrinkage, so lateral pressure is applied to the optical fiber. This results in an increase in optical transmission loss.

Therefore, recently, a method of inserting a nipple into a mold has been proposed as a method for centering the core (Japanese Unexamined Patent Publication No. 71839/1983). However, with this method,
When producing a thin optical fiber with an outer diameter of 1 mm or less, it is practically difficult to produce and use a correspondingly small nipple.

[Purpose of the invention]

The present invention has been made to solve these problems, and provides a method for manufacturing an FRP-coated optical fiber that allows sufficient centering of the core regardless of the diameter of the optical fiber. The purpose is to

[Structure of the invention]

For this reason, the present invention provides a centering die just before the mold, introduces the optical fiber core into the mold while centering it with the centering die, and guides the uncured fiber reinforced resin with the outer peripheral surface of the centering die. A method for manufacturing an FRP-coated optical fiber, characterized in that the fiber-reinforced resin is introduced into the mold, the outer peripheral surface of the optical fiber core is coated with the fiber-reinforced resin in the mold, and then the fiber-reinforced resin is cured. The main points are as follows.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a schematic explanatory diagram of an example of an apparatus for manufacturing an FRP-coated optical fiber of the present invention. In this figure, a centering die M is provided immediately before the mold 17.

The optical fiber core 1 is introduced into a centering die M via a guide plate (batten) N, and after being centered there, is guided to a mold 17.

On the other hand, the fibers 12 unwound from the fiber creel 11 pass through guide rollers 13 and 14 and are immersed in uncured resin 15. After being impregnated with the resin, the fibers 12 are passed from the guide rollers 16 to the guide plate N to the centering die M. It is introduced into the mold 17 while being guided by the outer peripheral surface of the mold.

The guide plate N has a through hole for the optical fiber core 1 at the center and has a through hole for the fibers 15 around it. Note that this guide plate N may be provided as necessary.

The centering die M is not specified as long as it can center the optical fiber core 1. However, the outer peripheral surface is devised in order to guide the resin-impregnated fibers-12. To do this, for example, grooves may be cut at equal intervals equal to the number of fibers 12, needles may be set up, or battens sufficient to allow the fibers to pass through may be provided. This allows the fibers 12 to enter the mold 17 uniformly.

The fibers 12 may be made of glass fiber, carbon fiber, or the like. It is preferable to use non-twisted fibers 12 and take them out while rotating the fiber creel 11 when untwisting them from the fiber creel 11 in order to improve the dispersion as much as possible.

The resin 15 may be either a thermosetting resin or an ultraviolet curable resin. Examples of the ultraviolet curable resin include unsaturated polyester resin, epoxy acrylate resin,
It is a composition consisting of a urethane acrylate resin, etc., a photosensitizer, etc.

In the mold 17, the outer peripheral surface of the optical fiber core 1 is uniformly coated with resin-impregnated fibers 12. Next, the resin is cured. If the resin is an ultraviolet curable resin, it is cured by ultraviolet irradiation from the ultraviolet lamp 18.

Then, it is taken off through the obtained FRP-coated optical fiber take-up roller 19.

〔Effect of the invention〕

According to the present invention having the above-described configuration, the following effects can be achieved.

fl+ Even when making a thin optical fiber with an outer diameter of 1111In or less, centering can be performed reliably.

(2) Since centering can be performed reliably, there is no eccentricity of the core, and therefore only eccentricity occurs in the FRP layer covering the core, so optical transmission loss can be reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an example of an apparatus for manufacturing an FRP-coated optical fiber of the present invention. 1... Optical fiber core, 11... Fiber creel, 1
2...Fiber, 13.14.16...Guide roller,
DESCRIPTION OF SYMBOLS 15... Resin, 17... Mold, 18... Ultraviolet lamp, 19... Take-up roller, M... Centering die, N... Guide plate, A... FRP coated optical fiber. Agent Patent Attorney Shin Ogawa − Kenshosai Noguchi Kazuhiko Shimo

Claims (1)

[Claims] A centering die is provided immediately before the mold, the optical fiber core is introduced into the mold while being centered by the centering die, and the uncured fiber reinforced resin is introduced into the mold while being guided by the outer peripheral surface of the centering die. A method for manufacturing an FRP-coated optical fiber, comprising: coating the outer peripheral surface of the optical fiber core with the fiber-reinforced resin in the mold, and then curing the fiber-reinforced resin.