JPS6259908A - Formation of terminal fixing means for optical fiber - Google Patents

Abstract

PURPOSE:To hold the center position of an optical fiber accurately and to fix the optical fiber strongly by providing a specific cavity and a receiving groove which connects with it in a metallic mold, and injecting resin and fixing the optical fiber. CONSTITUTION:The metallic mold consists of a moving mold 4-1 and a fixed mold 4-2 and is provided with the cavity 5 and grooves 6 and 7 for reception continuously. When a fixed part is formed, a fiber which is bared atop is placed in the groove 6 and a sheath coating part 3 is put in the groove 7; and the top and bottom metallic molds are superposed one over the other and resin suitable for the use of the optical fiber 2 is injected from charging ports 8 and 9 to fix the terminal. Consequently, the enter position of the fiber 2 in the fixing means is set accurately and the fiber is fixed strongly. In this case, massproduction is possible by the use of a metallic mold which has cavities 5 arrayed in parallel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming an optical fiber end fixing means, and more particularly to a method for forming an optical fiber fixing means by incorporating an optical fiber into a mold for forming an optical fiber fixing means and press-fitting a fixing means forming material. This is related.

Conventionally, when fixing the terminal, the outer covering of the terminal part of the optical fiber is peeled off, and the outer coating is removed from the terminal part, inserted into the terminal component, terminal, etc., and fixed by adhesion with adhesive or heat welding, etc., and when this fiber is inserted, the filament does not leak or become disordered. , sag easily occurs at the insertion part, which requires time and effort to correct, and quality deteriorates due to disordered filament alignment at the tip of the fiber.
Furthermore, since the contact surface between the outer periphery of the insertion port and the exterior sheathing is a bonding point made only by adhesive, there are problems such as being susceptible to damage from external forces. However, this requires crimping molds, presses, etc., which is uneconomical. However, the present invention solves these problems and eliminates troubles when inserting the fiber (the bonding with the outer sheathing does not occur). The purpose of this method is to improve quality, reduce defective products, and improve productivity. The place to do this is to place the optical fiber in the appropriate position in which the end fixing means is to be formed in a molding die, which has a cavity for forming the end fixing means and a groove for receiving one or two optical fibers continuous with the cavity. is inserted into a cavity through a groove in a mold, and then a forming material such as the synthetic resin is press-fitted into the cavity to form an end fixing means. Furthermore, two or more such continuous cavities can be installed in parallel to enable mass production.

The details of the present invention will be explained based on the illustrated embodiments. 1 in the figure is an optical fiber one end fixing means formed by the fixing means forming method of the present invention;
The terminal fixing means 1 is made of, for example, a synthetic resin, such as the above-mentioned epoxy, polyethylene, or light cured by ultraviolet rays. The mold resin, heat or low temperature curing resin, thermoplastic synthetic resin, etc. is selected from those suitable for the material and purpose of the optical fiber, and the optical fiber 2
The material is made of quartz glass, multi-component plastic, etc., and the exterior covering part 3 is made of vinyl chloride, polyethylene rubber, etc. However, the shape of the fixing means may be one in which a flange 1b is formed on the center outer periphery of a thick-walled pipe-shaped main body 1a as shown in FIG. 1, or a reflection type in which an optical fiber is branched into two (not shown). There is also a parallel arrangement of the ones shown in the figure, which are used for light guides, sensors, etc. For example, the dimensional ratio of each part is that the outer diameter of the fixing means is 6, the total length is 10, the outer diameter of the optical fiber coating is 2, the internal length of the outer coating is 3, and the length of the bare optical fiber is about 7. be done. The presence of the means-internal portion 3a of the exterior sheathing portion 3 serves as a buffer means to prevent damage caused by external forces at the joint with the fixing means. The mold for forming the fixing means consists of a movable die 4-1 and a fixed die 4-2 in FIG. The cavities 5 are formed as recessed grooves 7 or 6.7 that communicate with each other, and depending on the number of cavities, the cavities 5 can be a single type with one cavity installed, a continuous type with two cavities installed in series, or even this type. A mass-produced type with an appropriate number of parallel types (3rd type)
(as shown in the figure) etc. are adopted. Now, as shown in Fig. 2, place the fiber with the tip bare in the groove 6 at the optical fiber fixing position at one end of the mold, place the outer sheathing part 3 in the groove 7 at the other end at the outer sheathing part receiving and fixing position, and move it. In the case of mold 4-3, which fixes the fiber tip at two places inside by overlapping the mold and the fixed mold, and has 71 receiving grooves, fixing means 1 is used.
This is preferable when the fiber of In the case of .5 to 0.6 m/m, the occurrence of defective products due to eccentricity of the fiber position, which is likely to occur, is prevented. Therefore, the molding material is injected from a position that does not hinder operations such as mold polymerization, for example, from 8, 9, etc., and the fixing means 1
In addition to injection molding, compression molding and other molding methods may be used as appropriate.

Furthermore, 10 in FIG. 3 shows a case in which cavities 5 are installed in series, and the fiber 2 with the central portions A and B of the illustrated optical fiber exposed is placed in a groove located in the center of the mold. 6, and the exterior covering portion 3 is placed in the grooves 7.7 at both ends of the cavity, and then the molds are overlapped and fixed to form the mold. The part shown by the imaginary line in FIG. 3 is an example in which a larger number of these double cavities 5, 5 are provided in parallel.
An example of a mold suitable for mass production is shown below. Moreover, FIG. 4 shows an internal cross section showing the molding state of the continuous molds, in which the bare fiber 2 is positioned in the center, accurately fixed and held, and both ends are wrapped in the groove 7. This allows for mass production without the coating being held and moving during injection molding. After forming the fixing means 1 with a mold, the fixing means 1° is formed between both ends of the fibers by cutting out the fiber 2 portion located between the tips of each fixing means 1, 1, that is, the fiber 2 portion located in the groove 6. 1 can be integrally molded with the fiber. In addition,
When forming the fixing means 1, it is optional to interpose an adhesive 12 between the fixing means 1 and the fiber in order to more completely fix the fixing means 1 and the fiber.

Further, each of the above embodiments has shown an example in which the fixing means 1 is integrally molded, but as shown in FIG. Alternatively, a structure in which they are fixed to each other by means such as welding is also considered as another embodiment.

As described above, the method for forming an optical fiber terminal fixing means according to the present invention includes forming a cavity for forming the fixing means in a mold, and forming a groove for receiving an optical fiber continuous with the cavity. Since the optical fiber is received in the tee or groove to form the terminal fixing means, the position of the fiber within the fixing means is always set accurately in the center, and the fixing means is not fixed to the fiber after the fixing means is formed. It is strong and suitable for mass production.

[Brief explanation of the drawing]

Fig. 1 is an explanatory cross-sectional view of the state in which a terminal fixing means is formed at the tip of the optical fiber, Fig. 2 is an explanatory view of the mold, Fig. 3 is an explanatory view of another mold, and Fig. 4 is an explanatory diagram of the end fixing means in the mold. FIG. 5 is a cross-sectional view of the terminal fixing means using an adhesive, and FIG. 6 is a cross-sectional view showing the fixing means divided into two parts. 1: Fixing means, 2: Optical fiber, 3: Exterior coating, 4: Mold, 5: Cavity, 6: a, 7: Groove, 8.9: Filling port, 10: Continuous cavity, 11: Parallel Cavity, 12: Adhesive,
13: Two-split fixing means, Fig. 2 Fig. 1

Claims (1)

[Scope of Claims] 1) The terminal fixing means is attached to a molding die which has a cavity for forming the terminal fixing means and a groove for receiving one or two optical fibers continuous with the cavity. A method for forming a terminal fixing means for an optical fiber, which comprises placing an optical fiber to be formed into a cavity at an appropriate position through a groove in a mold, and then forming a terminal within the cavity. 2) A method for forming an optical fiber terminal fixing means according to claim 1, wherein two terminal fixing means are formed on one optical fiber at a constant interval. 3) Claim 1, in which a synthetic resin such as an epoxy resin, a polyester resin, a photocurable resin, a thermosetting resin, or a thermoplastic resin is used as the material for forming the terminal fixing means;
2. The method for forming an optical fiber terminal fixing means according to item 2. 4) A method for forming an end fixing means for an optical fiber according to claims 1, 2, and 3, which uses injection molding, compression molding, or the like as the method for forming the end fixing means.