JPH0523402B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to the structure of a connector for connecting optical fibers, particularly to the structure of a ferrule.

(Background Art) Generally, an optical connector having a structure as illustrated in FIG. 1 is used. In the figure, reference numeral 3 denotes a ferrule for positioning and fixing the optical fiber wire 1. After inserting the optical fiber wire 1 from both sides of the sleeve 4 as shown in the figure, the ferrule 3 is inserted into the fixing housing 5.
An optical connector is constructed by fixing the connector.

The ferrule of such an optical connector is as follows:
Conventionally, structures as shown in FIGS. 2 and 3 have been used. The one shown in FIG. 2 is of the optical fiber direct molding type, and has a metal pipe 8 on the outer periphery of the plug part 7 of the ferrule 6. Usually, the optical fiber wire 1 and the metal pipe 8 are inserted into the mold. It is integrally molded with the collar portion 10 using resin 9. When the bending strength of this fleur 6 is measured, it is, for example, about 5 kg on average.

The device shown in FIG. 3 is constructed entirely of metal, and the optical fiber 1 is inserted into the ferrule 11 from behind and fixed by adhesive. The bending strength of this ferrule 11 is
For example, the average weight is around 10 kg, and the above-mentioned optical fiber direct mold type is about half this amount.

Circumferential metal pipe ferrules are preferable in terms of mass production, cost, and reliability because they can be obtained by molding, but as mentioned above, they have the disadvantage that the bending strength is about half that of ferrules made entirely of metal. was.

(Disclosure of the Invention) The present invention was made to solve the above-mentioned problems, and the bending strength of the ferrule is improved.
The present invention aims to provide an optical connector that has excellent adhesiveness between metal pipes and resin and has low coupling loss.

The present invention provides an optical connector in which a ferrule with an optical fiber end fixed thereon is inserted from both sides of a sleeve for optical coupling, and the ferrule has an uneven inner or outer surface on a part of the outer periphery of the plug part. The present invention is an optical connector characterized in that it is formed of a metal pipe and that a part of the outer periphery of its collar also includes a metal pipe that has irregularities on its inner or outer surface.

Hereinafter, the present invention will be explained with reference to the drawings and examples.

FIG. 4 is a longitudinal sectional view showing an example of a ferrule in an embodiment of the connector of the present invention. In the figure,
The ferrule 12 has a plug part 13 and a collar part 14
Metal pipes 15 and 16 are provided on the outer periphery of the plug portion 13 and the outer periphery of the collar portion 14, respectively.

Both of the metal pipes 15 and 16 have irregularities on their inner and outer surfaces by swaging. Note that the unevenness may be provided only on the inner surface. Further, one end of a metal pipe 15 covering the outer periphery of the plug portion 13 is embedded and fixed within the collar portion 14.

Such unevenness on the inner surface of the metal pipes 15 and 16 improves adhesiveness with the resin 17, and
Further, by having a recessed portion on the outer periphery, the recessed portion has the effect of absorbing dust and abrasion powder during attachment and detachment from the sleeve.

Furthermore, by providing the metal pipe 16 on the outer periphery of the collar portion 14, the bending strength is significantly improved. When a force is applied to the tip of the ferrule 12 shown in FIG. 4, in the conventional type, the breakage was mainly due to the shearing force of the mold resin, but in the method of the present invention, the resin 17 is
5 and 16, and compressive force is required in addition to shear force for destruction.
The structure is such that the bending strength is improved accordingly.

Note that the metal pipe 15 may be a part of the outer periphery of the plug part 13, and the metal pipe 16 may also be a part of the outer periphery of the collar part 14.

Further, as another embodiment shown in FIG. 6, a metal pipe 16' having a fold 18 covering one end surface on the sleeve side end may be used as the metal pipe of the collar portion 14. In this case, the collar 1
4 has a further effect on compressive forces.

Further, the shapes of the inner or outer surfaces of the metal pipes 15, 16, 16' are not limited to the shapes shown in FIGS. 4 and 6, and are not particularly limited. In FIG. 6, the same reference numerals as in FIG. 4 indicate the same parts.

(Example) A ferrule of an optical connector according to the present invention was molded by a molding method as shown in FIG. In the figure, the same reference numerals as in FIG. 4 indicate the same parts.

First, in a mold 20 having a hole 21 with an inner diameter of 130 μm in the center, an outer diameter of 2.499±0.001 mm, an inner diameter of 2.0 mm,
A metal pipe 15 with a length of 10 mm and unevenness on the inner and outer surfaces, an outer diameter of 4.5 mm, an inner diameter of 4 mm, and a length of 4 mm,
A metal pipe 16 with irregularities on the inner and outer surfaces is inserted, an optical fiber wire 1 with an optical fiber 2 protruding from the center thereof or a molding pin is inserted, and an epoxy resin 17 is injected from a resin injection port 21. Molded.

When a molding pin was used, the molding pin was pulled out after molding, and the optical fiber 1 was inserted therein and fixed with an adhesive.

Thereafter, the end face of the ferrule 12 of the optical connector was polished to create the ferrule 12.

Plug part 1 of the obtained ferrule with an outer diameter of 2.5 mm
The length of the collar 3 was approximately 8 mm, the length of the collar 14 having an outer diameter of 4.5 mm was approximately 4 mm, and the length of the rear end portion of the collar 14 having an outer diameter of 2.5 mm was approximately 2 mm.

Using this ferrule, it was inserted from both sides of the sleeve 4 as shown in Fig. 1, and was fixed with a spring fixing housing 5 that generates pressure in the axial direction.The optical coupling loss was measured, and the average was 0.50 dB. The value was not a problem for practical use.

Furthermore, as shown in Fig. 7, the ferrule 12 was sandwiched between the chucks 22, 22, and a force F in a direction perpendicular to the tip of the plug part 13 was applied to measure the bending strength. It was hot.
Incidentally, the average weight of a conventional ferrule as shown in Fig. 2, which does not have a metal pipe on the outer periphery of the brim, is 5 kg, which has been improved by about 1.5 times with the present invention. Also, the average weight of all plastic molded ferrules is 2kg.
The present invention improved by about 3.5 times.

In addition, using the ferrule according to the present invention, the temperature between −30°C and +
As a result of a heat shock test at 70℃, 30
After 20 cycles and tests (n = 20), not a single metal pipe fell off, indicating that the unevenness of the metal pipe improves its adhesion to the resin.

In the above embodiments, a fixing housing as shown in FIG. 1 was used as the housing of the optical connector of the present invention, but the present invention may be applied to a screw-type housing using other springs or the like. , there are no particular restrictions.

(Effects of the Invention) The optical connector of the present invention configured as described above has the following effects.

(a) In the ferrule, a part of the outer periphery of the plug part is formed of a metal pipe that has unevenness on the inner or outer surface, and a part of the outer periphery of the collar part also has unevenness on the inner or outer surface. Since it is equipped with a metal pipe, due to the presence of the metal pipe with an uneven outer periphery and the Sanderch structure as mentioned above, compressive force is required in addition to shear force for fracture, which increases the bending strength by that much. Significantly improved.

For example, compared to a conventional ferrule (Fig. 2) that does not have a metal pipe on the outer periphery of the brim, it is approximately 1.5 times larger.
Approximately 3.5 times better than the all-plastic molded type ferrule.

(b) The unevenness on the inner surface of the metal pipe in the plug and collar parts improves the adhesion with the mold resin, so even when heat cycles are applied, the metal pipe does not fall off from the ferrule, and
Having a concave portion on the outer periphery also has the effect of absorbing dust and wear during attachment and detachment from the sleeve.

[Brief explanation of drawings]

FIGS. 1A and 1B are side views showing an example of an optical connector, where A shows the parts and B shows the assembled product. FIGS. 2 and 3 are longitudinal cross-sectional views showing examples of ferrules of conventional optical connectors, respectively. FIGS. 4 and 6 are longitudinal cross-sectional views showing examples of ferrules in embodiments of the optical connector of the present invention, respectively.
FIG. 5 is a longitudinal sectional view for explaining a method of forming the ferrule shown in FIG. 4. FIG. 7 is a longitudinal sectional view for explaining a method of measuring the bending strength of a ferrule in an embodiment of the present invention. 1... optical fiber line, 2... optical fiber, 3,
6, 11, 12...Ferrule, 4...Sleeve, 5...Housing, 7, 13...Plug part,
8, 15, 16, 16', 16''...metal pipe,
9,17...Resin, 10,14...Brim portion, 18
...Fold, 19...slit, 21...hole,
22...Check.

Claims (1)

[Scope of Claims] 1. An optical connector in which a ferrule with an optical fiber end fixed thereon is inserted from both sides of a sleeve for optical coupling, wherein a part of the outer periphery of the plug portion of the ferrule has an uneven inner or outer surface. It is formed of a metal pipe with one end embedded in the collar, and a part of the outer circumference of the collar.
An optical connector characterized in that it is formed of a metal pipe having irregularities on its inner or outer surfaces. 2. The optical connector according to claim 1, wherein the metal pipe of the flange of the ferrule has a folded end on the sleeve side.