JP3574620B2 - Ferrule of MT connector for optical fiber connection and connector for optical fiber connection using the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a connector for connecting an optical fiber, particularly to a ferrule for an MT connector which can be manufactured at low cost, a method for manufacturing the ferrule, and a connector using the ferrule.
[0002]
[Prior art]
A connector called an MT connector is known as one of connectors for connecting an optical fiber. The MT-type connector is a connector which can collectively connect multiple ribbon-shaped fibers using a rectangular plastic ferrule. This is as shown in, for example, FIGS. 1 to 3 of Japanese Patent Publication No. 6-54364.
[0003]
[Problems to be solved by the invention]
The ferrule of this MT type connector is mainly made of expensive epoxy resin or PPS resin, and is mainly manufactured by press molding in the case of epoxy resin, and is mainly manufactured by injection molding in the case of PPS resin. Has been produced. Ferrules manufactured by these methods must be formed with extremely high dimensional accuracy of the ferrule shape in order to keep the connection loss of the optical fiber to be connected low.
[0004]
In order to satisfy this requirement, expensive plastic materials, such as epoxy resin, are used.Also, the precision of the mold used in molding is always kept in good condition, and the total number of finished products or sampling inspection is performed. The pin hole, fiber guide hole diameter, hole straightness, eccentricity, etc. are inspected in detail, and if the specifications are out of the specified specifications, the mold is adjusted immediately to maintain high accuracy. ing.
[0005]
Particularly, in the case of ferrules for single mode optical fibers, at present, characteristics are checked strictly to maintain accuracy. For this reason, the number of ferrules manufactured by the press molding method or the injection molding method is limited (the number of molds is about four), and the price is high. Recently, the use of optical fiber connectors has been steadily increasing due to the promotion of IT and the like, and the emergence of low-cost, high-precision ferrules that meet the needs of users is expected.
[0006]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to manufacture a low-cost MT ferrule at a low cost and efficiently while maintaining the same accuracy and function as a conventional ferrule for an MT connector. An object of the present invention is to provide a ferrule for an MT type connector, a method of manufacturing the ferrule, and a connector using the ferrule.
[0007]
[Means for Solving the Problems]
The first invention is a ferrule of an MT connector that can collectively connect ribbon fibers of many cores by a plastic ferrule having a rectangular shape as a whole. The ferrule is made of plastic having good dimensional stability after molding and has a plurality of optical fibers. A tip portion, through which the fiber insertion hole extends from the back surface to the front surface, is integrally molded at the distal end of the ferrule main body, and the front surface of the tip portion is exposed so as to be the distal end surface of the ferrule main body. A rear surface of the tip portion is exposed to face a hollow portion provided at a central portion of an upper surface of the ferrule main body, and a projection is formed on an upper surface and / or a bottom surface of the tip portion. The projection is formed on the upper surface of the ferrule main body so as to coincide with the upper surface of the main body .
[000 8 ]
BEST MODE FOR CARRYING OUT THE INVENTION
An example of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 (A) to 1 (C), an adhesive for fixing a plurality of inserted optical fiber cores flows into a central portion of an upper surface of a ferrule main body 1 having a rectangular shape as a whole. Is provided, and the depth thereof reaches approximately half of the thickness S of the ferrule main body 1. On the bottom surface of the cavity 2, a plurality of grooves 2A for positioning the plurality of optical fiber cores are formed.
On the other hand, at the tip of the ferrule main body 1, a tip portion 3 formed of a plastic having good dimensional stability after molding, such as an epoxy resin, by a separate press molding method or an injection molding method is integrally formed in the ferrule main body 1. Molded.
[00 09 ]
Further, a guide hole 4 for introducing a plurality of optical fibers is formed at the rear end of the ferrule main body 1, and the guide hole 4 communicates with the cavity 2. In addition, guide pin guide holes 5 and 5 for inserting guide pins (not shown) for holding a pair of ferrule bodies 1 in close contact with each other near the side surfaces on both sides of the ferrule body 1 are provided. Penetrated.
[001 0 ]
The tip portion 3 has a rectangular shape as a whole as shown in FIGS. 2 (a) to 2 (c), and its width L is substantially the same as or slightly smaller than the width L of the ferrule body 1, and its length M is the ferrule body. 1 and the distance M between the end face of the optical fiber positioning groove 2 </ b> A in the cavity 2. Guide pin guide holes 31 communicating with the guide pin guide holes 5 and 5 are provided near the side surfaces on both sides of the tip portion 3. Further, a plurality of optical fiber insertion holes 6 and 6 communicating with the optical fiber positioning groove 2A of the ferrule main body 1 are penetrated from the back to the front in the tip portion 3.
[001 1 ]
Further, protrusions 7 are provided on the top and bottom surfaces of the chip portion 3 respectively. The width W of the projections 7, 7 is shorter than the width L of the ferrule body 1, and the distance between the tips of the projections 7, 7 is substantially equal to or slightly smaller than the thickness S of the ferrule body 1. The thickness H of the projection 7 is smaller than the length M of the tip 3.
[001 2 ]
Therefore, at least the front surface 32 of the tip portion 3 is exposed so as to be the tip surface of the ferrule main body 1, and the back surface 33 of the tip portion 3 faces the hollow portion 2 provided at the center of the upper surface of the ferrule main body 1. Is exposed. Furthermore, the height of the projections 7, 7 of the tip part 3 can be made to coincide with the upper surface of the ferrule main body 1, and this can be exposed on the upper surface of the ferrule main body 1.
[001 3 ]
Since the tip portion 3 is configured as described above, when the ferrule main body 1 is molded on the tip portion 3, the projections 7, 7 of the tip portion 3 function as reinforcing beams and are not deformed. In addition, since at least the front surface 32 of the tip portion 3 is exposed at the distal end surface of the ferrule main body 1, consistency with the other connector ferrule that contacts this distal end surface is ensured.
[001 4 ]
The shape of the tip portion 3 is not limited to the shape of the embodiment, and when the tip portion 3 is molded at the tip of the ferrule main body 1, the tip portion 3 is bent or deformed, or the tip portion 3 falls off. The shape may be such that the ferrule main body 1 can be engaged with the ferrule body 1 so that the ferrule body 1 is not engaged. For this reason, a U-shaped groove-shaped concave portion can be adopted instead of the projection 7.
[001 5 ]
Next, a method of manufacturing the ferrule will be described.
First, the chip portion 3 is formed in advance by a press molding method using a synthetic resin, for example, an epoxy resin. Then, the tip portion 3 is inserted into a predetermined molding die, and the cavity portion 2, the optical fiber positioning groove, the optical fiber core wire introduction guide hole 4, the guide pin guide holes 5, 5 are further inserted into the molding die. After positioning and installing the cores for forming the core, a molten synthetic resin, for example, a PPS resin is press-fitted into a mold, injected by, for example, an injection molding method, and cooled and solidified, and then each core is removed and molded. By moving the mold, the ferrule according to the present invention is obtained.
[001 6 ]
The method of forming the tip portion 3 may be an extrusion method other than the press molding method. In addition, as the material thereof, amorphous silicon, metal, or the like can be adopted in addition to the epoxy resin.
[001 7 ]
After inserting a multi-core ribbon fiber from the rear of the ferrule configured as described above, the individual optical fiber wires are finished smoothly at the tip end surface of the tip portion 3, and the pair of ferrules are abutted and closely contacted. The connector is configured by holding in the state.
[001 8]
【The invention's effect】
The present invention has the following effects because it is configured as described above.
(1) Since only the tip portion of the entire ferrule may be made of an expensive resin, for example, an epoxy resin, a low-cost ferrule can be obtained as a whole.
(2) The tip part determines the accuracy of the ferrule, but since the length of this part is shortened, the processing accuracy of the ferrule is improved, and the yield is improved as compared with conventional products.
(3) Insertion of the tip portion enables high-speed molding by the injection molding method, so that the overall cost can be reduced.
(4) When a conventional epoxy resin is used for the chip portion, the entirety of the conventional MT optical connector is an epoxy resin, so that compatibility with the conventional optical connector can be maintained.
(5) A large number of ferrules can be manufactured at the same time because insert molding is performed on a chip portion whose accuracy is previously secured.
(6) Since the tip has a tip structure, by changing the tip portion, it is possible to easily manufacture a ferrule for an MT connector having a high precision and a different number of optical fiber insertion holes.
[Brief description of the drawings]
1A is a plan view showing an example of the present invention, FIG. 1B is a cross-sectional view taken along line YY in FIG. 1A, FIG. 1C is a side view in FIG. 1A, and FIG. (B) Side view in FIG. 2 (a) (c) Cross-sectional view in FIG. 2 (a) showing an example of a chip portion used in the present invention.
DESCRIPTION OF SYMBOLS 1 Ferrule main body 2 Cavity part 3 Chip part 4 Optical fiber core wire introduction guide hole 5 Guide pin guide hole 6 Optical fiber insertion hole

Claims (4)

An MT connector ferrule that can connect a multi-core ribbon-shaped fiber at a time by a plastic ferrule having a rectangular shape as a whole,
A tip portion (3) made of plastic having good dimensional stability after molding and having a plurality of optical fiber insertion holes (6) penetrating from the back surface to the front surface thereof is integrally formed at the tip of the ferrule body (1). Molded,
The front surface of the tip portion (3) is exposed so as to be the tip surface of the ferrule body (1),
Further, the back surface of the tip portion (3) is exposed facing a hollow portion (2) provided at the center of the upper surface of the ferrule body (1) , and
A protrusion (7) is formed on the upper surface and / or the bottom surface of the tip portion (3), the height of the protrusion (7) is made to coincide with the upper surface of the ferrule body, and the protrusion is formed on the upper surface of the ferrule body (1). (7) The ferrule of the MT connector for optical fiber connection, wherein the ferrule is exposed . The ferrule of an MT connector for optical fiber connection according to claim 1, wherein the plastic forming the tip portion (3) is an epoxy resin. The ferrule of an MT connector for optical fiber connection according to claim 1, wherein the tip portion (3) is made of metal or ceramic. An optical fiber connection connector comprising a pair of ferrules according to claim 1, wherein tip end surfaces of a tip portion are closely held and opposed to each other.

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