JP2001228364A - Method for joining ferrule for optical fiber connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture first grade products in which optical loss hardly occurs by easily clearing strict accuracy requirement for the diameter and position of a hole as well as for the thickness. SOLUTION: In the manufacture of a ferrule for an optical fiber connector, a set of two ferrules is integrally made using metal, plastics and ceramics, with the integration cut in the center to form two ferrules, and with their sections brought into contact with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of joining a ferrule for an optical fiber connector. More specifically, the optical fiber connector has a cylindrical shape in which an optical fiber having a diameter of 0.125 mm.phi. By connecting the cores in the center of the optical fiber, the core is positioned exactly by connecting the cores to the optical fiber, and the connection is made up of several parts. And a method of joining parts generally called a ferrule.

[0002]

2. Description of the Related Art Conventionally, a ferrule, which is one of the components for an optical fiber connector, has, for example, a shape as shown in FIGS. 1 (a) and 1 (b), and is mainly made of zirconia ceramics. ing. FIG. 1A shows a single-core type ferrule 1 having a thickness of about 2 mmφ and a length of 8 mm.
A circular hole 2 having a diameter of about 0.127 mmφ is formed at the center of the column, and a two-core type is shown in FIG. 1 (b).

On the other hand, recently, for example,
An optical fiber connector using a multi-core ferrule capable of facilitating connection of two hundred core types or more is beginning to be demanded from the market, but the hole position, hole diameter and thickness of the multi-core ferrule are 1 micron. Extremely strict dimensional accuracy is required in units, and it is particularly difficult to precisely adjust the hole position to, for example, a pitch of 0.25 mm, especially for a multi-core type. Although it has begun to be manufactured, since dimensional accuracy is not obtained, simply fixing the optical fiber, the connection is carried out by welding which is a laborious manual work, and a multi-core type connector It is almost impossible to connect the optical fiber with the cable, it has not responded to the demands of the market. The difficulty of the accuracy of the outer diameter create a insufficient a primary product is at present.

In a ferrule for an optical connector made of a ceramic molded product such as zirconia, the accuracy of the hole position and the hole diameter is currently insufficient, so that a single-core type or a two-core type ferrule for an optical connector is partially manufactured. Despite this, the current situation is that the production cost is extremely high due to the hauling process, etc., and the cost is extremely high, and the ferrule with three or more cores is not practically practicable due to insufficient dimensional accuracy. Was.

Also, for example, after forming a mixture of a metal fine powder and a resin binder described in Japanese Patent Application Laid-Open No. 11-305069, removing the resin component, and then sintering at a high temperature, it is generally called metal forming. It has been proposed to manufacture a ferrule for an optical connector by the method described above, but there was a problem similar to that of the zirconia ferrule described above.

[0006] On the other hand, the present inventor has disclosed in Japanese Patent Application No. 10-3753.
No. 72 and Japanese Patent Application No. 11-376662, a metal or plastic wire is used as a matrix for electroforming, the wire is removed, and then a metal is used. He has proposed a ferrule, but has the following problems.

As for the hole diameter, there is no problem only by controlling the thickness of the line. However, at the position of the line, the line moves slightly during electroforming, and sometimes the position accuracy of the hole cannot be obtained. Or, during machining, the centering and the outer diameter were remarkably high, and the trouble-shooting failure rate was also high.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above,
In the manufacture of ferrules for optical fiber connectors, the extremely tight hole diameter of ± several microns and the accuracy of the hole position and outer diameter were easily cleared, making it impossible with conventional optical connectors of, for example, 10 to 100 core types or more. It is an object of the present invention to provide a method for easily manufacturing a ferrule for use without any problem.

[0009]

According to the present invention, in order to solve the above-mentioned problems, in the manufacture of a ferrule, two products are integrally formed as shown in FIG. Cut in the center to produce two ferrules,
A method of contacting the cut surfaces of the ferrule was adopted.

FIG. 2 is a schematic enlarged view of one embodiment of the multi-core type ferrule according to the present invention. The rod-shaped ferrule 1 is twice as long as a normal ferrule 1 and has twelve holes 2 formed therein. It has a V-shaped groove A at the center of the rod and is made of a material such as plastic, ceramic, or metal.

More specifically, in the case where the ferrule according to the present invention is manufactured from plastic, the molding method includes injection molding, compression molding, and cast molding which are usually performed using a carbide pin or the like as a core. The plastic material can be used for heat resistance, stress crack resistance, impact resistance, moisture resistance, chemical resistance such as water resistance, aging resistance, shrinkage rate and other dimensional stability. Any material can be used as long as it is excellent, and any of a thermoplastic resin and a thermosetting resin can be employed, and a liquid crystal resin can also be employed. As the thermoplastic resin, engineering plastics such as polyester resin, polyacetal resin, polyamide resin, and modified phenylene ether resin are preferable, and as the thermosetting resin, phenol resin, melamine resin, epoxy resin, and the like are preferable. Fibers such as glass fiber, carbon fiber, Kevlar, and Amorphous metal, or reinforced with whiskers such as alumina, silicon carbide, and graphite may also be used. Further, a method using a metal wire instead of a carbide pin for the core of the mold described in Japanese Patent Application No. 11-154213 filed by the present inventors may be used.

When the ferrule according to the present invention is manufactured from ceramic, the molding method can be injection molding, compression molding, extrusion molding or the like using a carbide pin or the like as a core pin, and the material is zirconia. Using a mixture of a ceramic fine powder such as a ceramic binder and a resin binder, heating and molding in accordance with the molding method described above,
After baking at about 00 ° C. to decompose and remove the resin, 13
It is manufactured by a method of sintering at about 00 ° C. and performing post-processing such as polishing.

When the ferrule according to the present invention is manufactured from a metal, a single or mixed metal fine powder such as Ni, Co, Fe, Cr, Mo, Ti, and Nb, which is generally called metal forming, is used. Using a mixture with a resin binder, molding by injection molding or compression molding using a carbide pin or the like as a core pin, firing at about 500 ° C to decompose and remove the resin component, then sintering at about 1400 ° C It is manufactured by a method of performing post-processing such as polishing.

Further, for example, the present inventor disclosed in Japanese Patent Application No.
In Japanese Patent Application No. 75372 and Japanese Patent Application No. 11-376662, one or more wires of metal or plastic are electroformed using a matrix, and after removing the wires, a method of machining such as nickel is used. Although a metal ferrule made of metal has been proposed, it is a desirable manufacturing method from the viewpoint that the hole diameter can be accurately obtained only by controlling the thickness of the wire and that physical and chemical properties are appropriate.

In this patent, in the case of a multi-core type,
For example, the electroforming is performed by a schematic device as shown in FIG. 3. In detail, in FIG.
It comprises a positive electrode 4, a holding jig 5, an air stirring nozzle 6, a spring 7, a negative electrode 8, and a wire 9.

A configuration in which a plus electrode 4 in which nickel balls are put in a cylindrical titanium basket in a heated electroforming solution 3 mainly containing nickel sulfamate or the like is arranged at four corners around a holding jig 5. A plurality of wires 9 such as a stainless steel wire are set around a holding jig 5 having a minus electrode 8 fixed in a state where the wires 9 are pulled by a spring 7. A method of manufacturing a ferrule for an optical connector by applying a current and electroforming into a cylindrical rod, followed by machining.

[0017]

According to the method of the present invention, in the manufacture of a ferrule for an optical fiber connector, two articles are integrally formed as shown in FIG. Since two ferrules were manufactured and the cut surfaces of the ferrules were brought into contact with each other, the same thing was cut originally, and the cut surfaces were brought into contact with each other. Even if the diameter is not accurate to some extent, there is no problem at all, as long as the dimensional accuracy of the hole diameter is sufficient and the optical fiber can enter exactly, it is a multi-core type ferrule that was practically impossible in the past. Also, the position of the hole and the accuracy of the outer diameter can be easily cleared, and a first-class product can be manufactured very easily.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below. A SUS304 wire having a perfect circular cross section of 0.127 mmφ is prepared, and twelve wires as shown in FIG. After being set in a state of being strongly pulled by the elasticity of a spring in a holding jig for casting 5 and washed with water, it is immersed in an aqueous solution of a mixed solution of Nikka Nontack A and B manufactured by Nihon Kagaku Sangyo at room temperature for 10 minutes and separated. After the mold treatment, it was thoroughly washed with water. On the other hand, in an electroforming bath containing nickel sulfamate as a main component, a nickel plate was used as an anode, the electroforming bath was subjected to high-speed filtration with a filtration accuracy of 1 μm, and a bath heated to 50 ± 2 ° C. was prepared. Then, electroforming was performed at a current density of about 4 to 6 A / dm ² using nickel as an anode to produce a rod-shaped nickel electroformed product having a thickness of about 2.5 mmφ. Then pull out twelve lines, then N
C Automatic processing machine, centerless processing machine, etc., as shown in FIG. 2, a set of two pieces, 2.000 mm in thickness and 16.50 m in length
m, a product having a V-shaped groove A in the center was manufactured. Next, the optical connector is cut at the groove A, and the cut surface is polished to form two ferrules and assembled into an optical connector. Then, an optical fiber is adhered to the hole of the optical connector, and the cut surfaces are brought into contact with each other. The product was tested and found to have very little loss of light and no problem within specifications.

[0019]

The present invention has the following effects by the method described above. In the manufacture of ferrules for optical connectors, instead of individual production as in the prior art, FIG.
As shown in Figure 2, two ferrules were manufactured integrally, cut at the center, two ferrules were manufactured, and the cut surfaces of the ferrules were brought into contact with each other. It is difficult to manufacture first-class products due to the strictness of required accuracy, and especially in the case of multi-core type ferrules, the point that production was virtually impossible was improved, and light loss was easy. A first-class product with almost no odor can be manufactured.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view and a side view of a ferrule according to a conventional method.

FIG. 2 is an enlarged cross-sectional view and a side view of one embodiment of a two-piece, one-piece ferrule according to the present invention.

FIG. 3 is a schematic configuration diagram showing one embodiment in the case of manufacturing with an electroforming apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Ferrule 2 True circular hole 3 Electroforming liquid 4 Positive electrode 5 Holding jig 6 Air stirring nozzle 7 Spring 8 Negative electrode 9 wire

Claims (6)

[Claims] A ferrule for an optical fiber connector, wherein two products are integrally formed, cut near the center, two ferrules are manufactured, and the cut surfaces of the ferrules are used in contact with each other. A method for joining ferrules for fiber connectors. 2. The method according to claim 1, wherein said ferrule is applied to a multi-core type ferrule having two or more cores. 3. The method according to claim 1, wherein a plastic molding is used for the ferrule. 4. The method according to claim 1, wherein a ceramic molded product is used for the ferrule. 5. The method according to claim 1, wherein a metal molding is used for the ferrule. 6. The method according to claim 1, wherein said ferrule is formed by forming a rod made of plastic, metal or the like into a matrix, forming a rod shape by electroforming, and then processing. Item 7. The method according to Item 1.