JPS6135530B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a core mold for a core in a multi-core optical connector for connecting a plurality of optical fibers.

Japanese Patent Laid-Open No. 55-41485 discloses a method for processing optical fiber connection ends when optical fiber cables (or optical fiber units) having a plurality of optical fibers are connected using connectors. There is a method for manufacturing an optical fiber connector terminal. As shown in Figure 1A and B, this means that
The spheres 02 are closely arranged in the frame 01, and the optical fiber 03 is inserted into the gap between the spheres 02.
In this state, the resin 04 is poured into the frame 01 to manufacture an optical fiber connector terminal. However, with this method, inserting the optical fiber 03 into the gap is technically difficult and requires skill, and it lacks mass productivity.
Furthermore, since it requires a mold and a heater, it is unsuitable for on-site work, and it also has disadvantages such as a long curing time for the resin.

On the other hand, as a single-core connector for connecting a pair of optical fibers, as shown in Fig.
The strand of optical fiber 03 is inserted into the microhole 05 of the core 06, which has a microhole 05 with approximately the same diameter as the outer diameter of the strand of strand 3 without eccentricity, and is inserted into the sleeve 0.
A method is known in which the optical fibers 03 are connected to each other by inserting them into the optical fibers 7. It is conceivable that this method could be used to connect multi-core optical fiber cables, but manufacturing a core with multiple microholes placed precisely through plastic molding would require an extremely complicated mold structure. It is considered difficult.

The present invention has been made in view of the above-mentioned current situation, and it is an object of the present invention to provide a method for manufacturing a core mold that can accurately and economically mass-produce the core of a connector used for connecting multi-core optical fibers.

The gist of the present invention to achieve the above object is to
A pin with approximately the same diameter as the optical fiber wire is inserted into the microscopic hole of the mold body, which has a plurality of small holes arranged in a row, and in this state, conductive treatment is applied to the surface of this mold body to form a master mold. A metal layer is formed around the master mold by electroforming, and this metal layer is separated from the master mold to obtain a concave mold from which the pins protrude from the bottom. are arranged in the same manner as the pins to form a mold, and this mold and the mold are combined so that the tip of the bar and the tip of the pin are butted together to form a core mold. Features.

EMBODIMENT OF THE INVENTION Hereinafter, the manufacturing method of the core mold based on this invention is demonstrated in detail based on the Example shown in drawing.

FIGS. 3A and 3B show a core manufactured by a core mold obtained by the method of the present invention. Figure 3A
The core 1 shown in the figure is used to connect round multi-core optical fiber cables, and the plastic main body 2 has a cylindrical shape, and has a micro hole 3 in the center and on the same circumference and connected to it. Insertion holes 4 are arranged and bored. The microhole 3 is a place where a bare wire portion of the optical fiber is housed, and the insertion hole 4 is a place where a core wire portion is housed. The core 5 shown in FIG. 3B is used to connect tape-shaped optical fiber cables made by arranging optical fibers in parallel.The main body 6 made of plastic has a flat shape, and has a microhole 3 and an insertion hole connected to it. Holes 4 are arranged and bored in parallel.

A core mold (molding mold) for plastic molding the core 5 shown in FIG. 3B can be manufactured by the method of the present invention as follows.

First, as shown in FIG. 4, a plurality of cylindrical bodies 8 of uniform precision each having a minute hole 7 of the same diameter as the optical fiber wire in the center of one end without eccentricity (the diameter of the cylindrical body 8 to be connected The cylindrical bodies 8 are held in a housing 9 in close contact with each other, and a resin (for example, epoxy resin) 10 is poured thereinto to form a mold body (cylindrical aggregate) 11.

Next, as shown in FIG. 4, steel pins 12 of the same diameter are inserted into each microhole 7 of the mold body 11 to a predetermined depth.
In this state, metal vapor deposition is performed to form a thin conductive layer on the entire surface of the mold body 11, and this is applied to the master mold 11a.
shall be.

Next, as shown in FIG. 4, the master mold 11a
is immersed in an electroforming bath (for example, a nickel electroforming bath) 13 to perform electroforming, thereby producing an electroformed layer (metal layer) 14 around the master mold 11a. In Figure 4, 1
5 is a nickel rod, and 16 is a power source.

When the electroformed layer 14 grows to a predetermined thickness, electroforming is finished. After this, from the master mold 11a to the electroformed layer 14
pull out. The pin 12 is integrated with the electroformed layer 14 and removed from the microhole 7. In other words, as shown in FIG. 4, a concave mold 14a with pins 12 protruding from the bottom surface is obtained. The arrangement precision of the pins 12 in this mold 14a is equivalent to the arrangement precision of the minute holes 7 in the mold body 11. Note that, if necessary, the end face and side face of the mold 14a are cut.

On the other hand, as shown in FIG. 5, by preparing the same number of rods 17 having approximately the same diameter as the optical fiber core wire and implanting them in the mold member in the same arrangement as the pins 12, the other A mold 18 is obtained.

Then, this mold 18 and the mold 14a are combined so that the tip of the bar 17 and the tip of the pin 12 are butted together to form a core mold (molding mold).
It is set as 9.

By performing plastic molding within this core mold 19, a core 5 as shown in FIG. 3B can be manufactured with high precision. The pin 12 portion becomes the microhole 3, and the bar 17 portion becomes the insertion hole.

FIG. 6 shows another embodiment. This is to manufacture a core mold used for manufacturing a core corresponding to the core 1 shown in FIG. 3A. First, as shown in FIG. 8
are closely arranged in the cylindrical housing 20, and the housing 20
Resin 10 is injected inside and between the cylindrical bodies 8 to form a mold body 21.
form. In this case, it is preferable to remove the resin 10 from one or two places on the side surface to form a keyway 22 that serves as a rotation stopper.

Next, as shown in FIG. 6, a steel pin 12 of the same diameter is inserted into the microhole 7 of the mold body 21 to a predetermined depth, and conductive treatment is performed in this state to form a thin conductive layer on the surface of the mold body 21. A master mold 21a is formed.

Thereafter, in the same way as in the previous embodiment, a metal layer is formed around the master mold 21a by electroforming, and this metal layer is separated from the master mold 21a to form a mold in which the pins 12 protrude from the bottom surface. obtain. The other mold that is combined with this mold is an optical fiber core wire.
This can be obtained by planting rods having approximately the same diameter in the mold member in the same number and arrangement as the pins 12.

FIG. 6 shows a connection structure using a core 1 obtained from a core mold made of the two molds described above. The core 1 is inserted into the sleeve 23 with its keyway 22 aligned with the guide pin 24 inside the sleeve 23.
In the figure, 25 is a spacer.

Incidentally, the master mold for the core mold of the core 1 as shown in FIG. 3A can also be formed by a cylindrical body having no microholes. As shown in FIG. 7, this utilizes the substantially triangular gaps 27 between the cylindrical bodies 26 that are created when the cylindrical bodies 26 are arranged in close contact with each other. The cylindrical body 26 is formed so as to fit accurately with the steel pin 12 having approximately the same diameter as the wire. In other words, here, the substantially triangular gap 27 becomes a microhole. In addition, as another method for manufacturing the master mold, the 8th
There is also a method as shown in the figure. This involves preparing a metal ring 30 with a highly accurate inner diameter, and inserting a minute hole 7 in the center of the ring 30 as shown in the figure.
A plurality of cylindrical bodies 8 with cylindrical bodies 8 are pressed into close contact with each other, adhesive 10 is poured into the gaps, and then the outer periphery of the ring 30 is cut with precision so that the cylindrical bodies 8 inside are not eccentric, and the axes are aligned. A master mold is formed by forming a groove 31 for use in the mold.

Next, the method for manufacturing the core mold according to the present invention will be described by giving actual numerical values, and the performance of the core mold manufactured by the obtained core mold will be shown.

Outer diameter 1.5±0.001mm, micro hole inner diameter 0.126±0.001
Six cylindrical bodies with an eccentricity of 0.001 mm or less are arranged in a horizontal row in close contact with each other, and epoxy resin is poured into them.
A mold body (oblate cylindrical aggregate) as shown in FIGS. 4A and 4B was formed. After this, a steel pin with a diameter of 0.125 mm was inserted approximately 1.2 mm into each of the six microholes, and in this state, a master mold was prepared in which 700 Å of gold was deposited on the entire surface of the mold. This master mold was immersed in a nickel electroforming bath for 20 days at a current density of 10 mA/cm ² and a temperature of 35° to form a nickel layer to a thickness of about 7 mm. Thereafter, the nickel layer was separated from the master mold, and its peripheral portion was shaped to obtain one molding die. on the other hand,
Another mold was made as previously explained in the example, and this was combined with the mold to form a core mold.

Using this core mold, a 6-fiber connector core was molded by injection molding of ABS resin, and the dimensions were measured. As a result, the dimensional error was ±0.002 mm from the set value.
The following good results were obtained. The microhole in this core (corresponding to microhole 3 in Figure 3B) has an outer diameter of 0.125mm.
After inserting a six-core tape-shaped graded quartz fiber with a core diameter of 0.050 mm and fixing it with epoxy adhesive, a pair of cores with polished end faces were processed with high precision. A multi-core connector was constructed by inserting it into a receptacle. As a result of measuring the connection loss using an LED (light emitting diode) light source with a wavelength of 0.85 μm, an average value of 0.7 dB was obtained.
The time required from inserting the optical fiber to polishing the end face of the core was about 30 minutes.

As explained above, according to the method for manufacturing a core mold for a multi-fiber optical connector according to the present invention, a mold for forming a core (core mold) having micro holes into which a plurality of fibers are inserted can be manufactured with high precision. As a result, high-precision, low-connection-loss multi-core optical connector cores can be mass-produced at low cost by plastic molding. Further, since electroforming can be performed multiple times using the same master mold, a large number of molds with uniform precision can be prepared, and the quality of the molded product can be maintained constant.

[Brief explanation of the drawing]

Figures 1A and B are plan and side views showing a conventional method for manufacturing a multi-fiber optical connector terminal, Figure 2 is a sectional view of a conventional single-fiber connector, and Figures 3A and B are according to the present invention. FIG. 4 is a partially cutaway perspective view of a core manufactured by the core mold obtained by the method, and FIG. The figure is a sectional view of a core mold obtained by the method of the present invention,
is an explanatory diagram of a part of the process of another embodiment, FIG. 6 is a cross-sectional view showing a connector connection using a core manufactured by the obtained core mold, and FIGS. 7A and B are still another embodiment. An explanatory diagram of an example, FIG. 8 is an explanatory diagram showing another method of manufacturing a master mold. In the drawing, 1 and 5 are cores, 3 is a microhole, 4 is an insertion hole, 7 is a microhole, 8 is a cylinder, 10 is resin, 11
is a mold body, 12 is a steel pin, 11a is a master mold, 14
14a is an electroformed layer, 14a is a mold, 17 is a bar, 18 is a mold, and 19 is a core mold. 〓〓〓〓

Claims (1)

[Claims] 1 Insert a pin with approximately the same diameter as the optical fiber wire into the microholes of a mold with a plurality of microholes arranged at its tip, and in this state conductive treatment is applied to the surface of the mold to create a master. A metal layer is formed around this master mold by electroforming, and this metal layer is separated from the master mold to obtain a concave mold with the pins protruding from the bottom. A mold is formed by arranging rods having the same diameter as the pins, and this mold and the mold are combined so that the tips of the rods and the pins butt against each other to form a core mold. A method for manufacturing a core mold for a multi-core optical connector, characterized in that: