JPS59172605A - Terminal part reinforcing device for flexible optical fiber bundle - Google Patents

Abstract

PURPOSE:To reinforce the boundary part between the hard part and flexible part of the terminal part of an optical fiber bundle by drawing the terminal part side of a ferrule to the flexible part side, and covering the outer circumference of the flexible part of the ferrule with a heat-shrinkable tube from the ferrule to close to the ferrule. CONSTITUTION:The ferrule 13 almost in a pipe shape is fitted around the hard part 11 of the optical fiber bundle and fixed with an adhesive. This ferrule 13 has one end part side drawn out slightly toward the flexible part 12, and while the end part on the side of the flexible part 12 is stepped to a small external diameter, a projection part 14 is formed at the center part of the step part. On the other hand, the outer circumferential part from the projection part 14 of the ferrule 13 to the flexible part 12 close to the ferrule 13 is covered tightly with the heat-shrinkable tube 15. Consequently, the boundary part where the hard part 11 and flexible part 12 of the optical fiber bundle are discontinuous enters the internal diameter part of the ferrule 13 slightly, so any force which bends the optical fiber bundle does not operate directly thereupon, so the optical fiber bundle is not broken there, thus reinforcing the boundary part easily.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention provides a flexible optical fiber bundle whose end portion has a hard part and a cap is fitted into the hard part, in which the optical fibers near the cap are The present invention relates to an end reinforcement device having a structure for reinforcing bundles.

"Technical Background of the Invention and its Problems" In recent years, optical fiber bundles have come to be widely used as means for transmitting optical images or illumination light.

The optical fiber bundle is formed by converging a large number of optical fibers (elements) having a sufficiently small diameter. As shown in FIG. 1, an optical fiber 1 has a core glass 2 with a relatively high refractive index made of, for example, barium flint glass, and an acid-resistant glass with a relatively low refractive index coated around the core glass 2. The coated glass 3 is made of, for example, crown flint glass, and the acid-soluble acid-leaching glass 4 coated on the outside thereof is made of, for example, borosilicate glass. Then, a large number of the optical fibers [11] are bundled together, heated, heat-sealed, stretched, and cut to form, for example, two optical fibers as shown in FIG.
0) Optical fiber 1 with J diameter is approximately 10,000 pieces and has an outer diameter of 2 m.
rn, a conduit 5 with a length of 1000 mm is manufactured.

Both ends of this condot 50 are sealed with tubes 6 made of a substance insoluble in the solvent, as shown in FIG. Then, in a container containing a solvent, the acid-leached glass 4 of the optical fiber 1 in the intermediate portion other than that sealed with the tube 6 is melted out, the fusion between each fiber is removed, and each fiber is separated. Therefore, only the both ends sealed with the tube 6 remain as a rigid part, and the middle part is a flexible optical m with a flexible part 7 formed thereon.
A string bundle is manufactured. Adhesive is applied to the hard parts at both ends of the optical fiber bundle manufactured in this manner, and a base is fixed thereto. However, as it is, the boundary between the hard part and the flexible part near the end of the mouthpiece is brittle, which may cause problems in use, and some kind of reinforcement must be provided. Conventionally, as shown in Fig. 4, a pipe-shaped cap 9 whose inner diameter is the outer diameter of the hard part 8 at both ends of the optical fiber bundle is inserted into both ends of the optical mI# bundle and fixed with adhesive. , and an adhesive, such as Cemedine, is applied or impregnated on the part (A part) extending from the boundary between the hard part 8 and the flexible part 7 to the flexible part 7 side,
It consisted of a reinforced structure.

However, in a configuration consisting of a structure like this, the optical fiber N1
As a result, light from the broken part is not transmitted, resulting in a black appearance.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and is aimed at reinforcing the boundary portion between the hard part (M non-eluting part) and the flexible part (acid eluting part) at the end of the optical fiber bundle. An object of the present invention is to provide an end reinforcing device for a flexible optical fiber bundle having a structure of:

[Summary of the Invention] To achieve the above object, the present invention provides a flexible optical fiber bundle whose end portion has a hard part and a cap is fitted into the hard part, in which the end side of the cap is flexible. It is characterized by a structure in which a heat-shrinkable tube extends toward the flexible portion and covers the outer periphery of the flexible portion of the cap to the outer periphery of the flexible portion adjacent to the cap.

Further, in order to achieve the above object, the present invention provides a flexible optical tile whose end portion has a component and a base is fitted into the hard portion.
T-bundle with a string, extend the end side of the cap to the flexible part side, and cover the heat shrinkable tube from the outer periphery of the flexible part side of the cap to the outer periphery of the flexible part close to the cap. , and the flexible portion near the base is coated with or impregnated with an adhesive.

[Embodiments of the invention] Hereinafter, the present invention will be specifically described with reference to the drawings.

FIG. 5 relates to the first embodiment of the present invention, and shows a sectional view when the base is thick at the end of the optical fiber bundle.

In this figure, optical 4! 'The end of the fiber bundle is the rigid part 11 (
The middle part is a flexible part 12 (acid-eluting part). The hard part 11 has a substantially pipe-shaped base 1.
3 is fitted and fixed with adhesive. This cap 1
3 has one end extending somewhat toward the flexible section 12, and the end of the cap 13 on the flexible section 12 side is formed into a stepped shape with a small outer diameter.

A protrusion 14 is formed at the center of this step. On the other hand, from the protrusion 14 of the base 13 to the base 13
The outer periphery of the nearby flexible portion 12 is tightly covered with a heat-shrinkable tube 15 .

In the flexible optical fiber bundle end reinforcement device of the first embodiment configured as described above, the hard part 11 and the flexible part 1 of the optical fiber bundle are
Since the discontinuous boundary portion of No. 2 is slightly inside the inner diameter of the base 13, a force that bends the optical fiber bundle does not directly act on that portion, so that the optical fiber bundle will not be broken at that portion. Further, the heat-shrinkable tube 15 is covered with the largest outer diameter by the protrusion 14 of the base 13, and is most tightly adhered to the protrusion 14. The elasticity of the heat-shrinkable tube 15 provides resistance to bending of the optical fiber bundle in the vicinity of the base 13 from the protrusion 14 of the heat-shrinkable tube 15 to the flexible portion 12 side. The flexible portions 12 can be tied together and reinforced. In addition, in this embodiment, a thick-walled cap 13 is used to attach the heat shrink tube 1.
The outer diameter of the protrusion 14 covered with the cap 5 can be configured so that it does not particularly protrude from the other outer diameter portion of the cap 13.

FIG. 6 relates to a second embodiment of the present invention, and shows a sectional view when the base is thin at the end of the optical fiber bundle. In this diagram,
Like the first embodiment of the optical fiber bundle, it is formed of a hard part 11 and a flexible part 12. The cap 16 fitted on the hard part 11 side has a substantially pipe shape and is fixed to the flexible part 11 with an adhesive. One end of the cap 16 extends somewhat toward the flexible portion 12, and a protrusion 17 is formed on the outer periphery of the cap 16. On the other hand, the base 1
A heat-shrinkable tube 18 is tightly coated on the outer periphery between the protrusion 17 of 6 and the flexible portion 12 near the base 16.

In the flexible optical fiber bundle end reinforcing device of the second embodiment configured in this way, the optical IJ1 is given resistance against bending of the bundle near the base 16, as in the first embodiment. In addition, the flexible portion 12 can be tied and reinforced.

In addition, in this embodiment, a thin-walled base 16 is used to
The protrusion 17 is covered with a heat-shrinkable dupe 18, and is used particularly when the outer diameter of the optical fiber bundle is large and the protrusion of the protrusion 17 is not a problem.

FIG. 7 relates to a third embodiment of the present invention, and does not show a cross-sectional view when the adhesive is evenly applied to the end of the optical fiber/string bundle. In the first embodiment, an adhesive is applied from the boundary between the hard part 11 and the flexible part 12 of the optical m-string bundle to the near side of the part covered with the heat shrink tube 15 (part 8 in FIG. 7).
For example, it has a structure in which a silicone-based adhesive or the like is evenly applied (hereinafter referred to as "impregnation").

In the flexible optical yAN bundle end reinforcing device of the third embodiment configured as described above, in addition to being reinforced in the same manner as in the first embodiment, the ends are further bound and reinforced with adhesive. . The problems that arise when only adhesive is used are covered by the reinforcement of the heat-shrinkable duplex 15.

FIG. 8 relates to a fourth embodiment of the present invention, and shows cross-sectional views when the amount of adhesive is applied to the end of an optical fiber bundle in a stepwise manner. The adhesive of the third embodiment is applied in a stepwise smaller amount toward the flexible portion 12.

In the flexible optical fiber bundle end reinforcing device of the fourth embodiment configured as described above, in addition to being reinforced in the same manner as in the first embodiment, the darkness of the adhesive is gradually reduced in the C portion. As a result, the degree of binding from the hard part 11 to the flexible part 12 changes in stages, resulting in even better reinforcement.

FIG. 9 relates to a fifth embodiment of the present invention, and shows a cross-sectional view when a small amount of adhesive is continuously applied to the end of an optical fiber bundle. The adhesive of the third embodiment is applied to the D portion in a continuously smaller amount toward the flexible portion 12 side.

In the flexible optical fiber bundle end reinforcing device of the fifth embodiment configured as described above, since a small amount of adhesive is continuously applied, the binding from the hard part 11 to the flexible part 12 is difficult. Since the degree of transition is smoother than in the fourth embodiment, reinforcement is improved.

In the above embodiment, the protrusions are provided in a ring shape in one row on the outer periphery of the cap, but they may be provided in several rows in a ring shape or in scattered dots on the outer periphery, and the shape is also the same as in the embodiment. It is not limited to the shape of

[Effects of the Invention] As described above, according to the present invention, in a flexible optical fiber bundle in which the end portion of the optical fiber bundle has a hard part and a cap is fitted into the hard part, the cap can be made somewhat flexible. Since it extends to the flexible part side and its outer periphery is covered with heat-shrinkable dew, the flexible part of the optical i-string bundle at the end of the cap is bound, preventing problems such as breakage of the optical fibers in that part. It can be easily reinforced without causing damage.

Further, in addition to providing the cap and the heat shrink tube in the same way as above, since an adhesive is also used, it can be further bundled and reinforced. Furthermore, by applying a smaller amount of adhesive in stages or continuously toward the flexible part, the degree of binding from the hard part to the flexible part can be smoothly transferred and reinforcement can be improved. I can do it.

[Brief explanation of the drawing]

Fig. 1 is an enlarged sectional view of an optical fiber bundle having an acid-leaching glass layer, Fig. 2 is a perspective view of a conduit, Fig. 3 is a perspective view of a flexible optical fiber bundle, and Fig. 4 is a conventional example. FIG. 5 is a cross-sectional view of the end of the optical fiber bundle according to the first embodiment of the present invention, and FIG. 6 is a cross-sectional view of the end of the optical fiber bundle when the base is thick. FIG. 7 is a cross-sectional view of the second embodiment when the cap is thin at the end of the optical fiber bundle, and FIG. li
FIG. 8 is a cross-sectional view of the fourth embodiment of the present invention, and FIG. FIG. 7 is a cross-sectional view when a small amount of adhesive is continuously applied to the end of the optical fiber bundle according to the fifth actual flow example. 11... Hard part 12... Flexible part 13.16... Cap 14.17... Projection part 15.18... Heat shrink tube representative Patent attorney Susumu Ito Figure 1
Figure 2 Figure 4 Figure 5 Figure 6

Claims (10)

[Claims] (1) Flexible optics with a hard part at the end and a cap fitted into this hard part! ! In the fiber bundle, the end side of the cap extends toward the flexible portion, and a heat-shrinkable tube is coated from the outer periphery of the flexible portion of the cap to the outer periphery of the flexible portion adjacent to the cap. Flexible optics i characterized by
End reinforcement device for string bundles. (2) The cap has a protrusion formed on the outer periphery of the flexible portion, and is covered with a heat shrink tube so as to cover the protrusion. An end reinforcement device for a flexible optical m-string bundle. (3) The end reinforcing device for a flexible optical fiber bundle according to claim 2, wherein the protrusions are formed in one or several rows in a ring shape around the outer periphery of the base. (4) The end reinforcement device for a flexible optical fiber bundle according to claim 2, wherein the protrusions are formed in a dotted manner on the outer periphery of the base. (5) The mouthpiece is characterized by having a thick wall and a stepped portion having a small outer diameter on the side of the flexible portion, and a projection portion being formed at approximately the middle of the stepped portion. An end reinforcement device for a flexible optical fiber bundle according to claim 2. (6) The device for reinforcing the end of a flexible optical fiber bundle according to claim 2, wherein the cap is thin and has a protrusion formed on the outer periphery of the cap. . (7) In a flexible optical fiber bundle whose end has a hard part and a cap is fitted into the hard part, the end of the cap extends somewhat toward the flexible part, and A flexible device characterized in that the outer periphery of the flexible portion near the base is covered with a heat-shrinkable tube, and the flexible portion near the base is coated with or impregnated with an adhesive. end reinforcement device for optical fiber bundles. (8) The end reinforcing device for a flexible optical fiber bundle according to claim 7, wherein the adhesive is applied or impregnated almost uniformly on the flexible portion. (9) The adhesive spreads farther away from the end of the cap on the flexible part.
8. The end reinforcing device for a flexible optical fiber bundle according to claim 7, wherein the end reinforcing device for a flexible optical fiber bundle is constructed by applying or impregnating the amount of the same in a stepwise manner. (10) Flexibility according to claim 7, characterized in that the adhesive is applied or impregnated in a smaller amount in the flexible portion as the distance from the end of the cap increases. Optical fiber bundle end reinforcement device.