JP2003114361A - Method for manufacturing core and ferrule using the core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core, with which a ferrule with low connection loss of an optical connector can be manufactured and a method of manufacturing the ferule using the core. SOLUTION: Disclosed is the method for manufacturing the core 1 which has a plurality of pins 2 for forming fiber holes of a ferrule gripped in a plurality of holding grooves 1c formed in pin holders 1a and 1b respectively and also the method for manufacturing the ferrule using the core 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a core and a method for manufacturing a ferrule using the core.

[0002]

2. Description of the Related Art Ferrules for optical connectors are known which use synthetic resin for the purpose of manufacturing at low cost while maintaining the accuracy of fiber holes and pin holes of positioning pins. When manufacturing such a resin ferrule, for example, a core in which a plurality of pins forming the fiber hole of the ferrule are collectively arranged in a line in the recess of the pin holder is used.

[0003]

By the way, it is difficult for the core to hold each pin with high accuracy simply by arranging a plurality of pins in a line in the recess. Therefore, in a ferrule manufactured using such a core, it is difficult to realize an optical connector having a small connection loss, for example, an average connection loss of 0.1 dB or less. In particular, in an optical connector in which a plurality of optical fibers are arranged in a plurality of rows in a row, it is more difficult to suppress the connection loss.

The present invention has been made in view of the above points, and an object thereof is to provide a core and a method for manufacturing a ferrule using the core, which are capable of manufacturing a ferrule with a small connection loss in an optical connector. And

[0005]

To achieve the above object, in the core of the present invention, a plurality of pins forming fiber holes of a ferrule are held in a plurality of holding grooves formed in a pin holder. It is configured to be.
Preferably, the plurality of pins are held in a plurality of stages by the pin holder via spacers.

Further preferably, a holding groove for holding the pin is further formed in the spacer.
Further, in order to achieve the above object, in the ferrule manufacturing method of the present invention, a plurality of pins forming the fiber hole of the ferrule, a core held in each of the plurality of holding grooves formed in the pin holder, and the ferrule. The molding pin for forming the pin hole through which the positioning pin is inserted is arranged in the mold, and the synthetic resin is injected into the mold for manufacturing.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION One embodiment of a core and a method for manufacturing a ferrule using the core of the present invention will be described in detail below with reference to FIGS. First, a core and a first embodiment of a ferrule manufacturing method using the core of the present invention will be described.

As shown in FIG. 1, the core 1 has a plurality of pin holders 1a and 1b, for example, eight pins 2 and two pins 3 are held. As shown in FIGS. 1 and 2, the pin holders 1a and 1b are U that individually hold a plurality of pins 2.
Pin grooves 1e and 1 formed of V-shaped holding grooves 1c and 1d and square concave grooves for holding the pins 3 on both sides of the holding grooves 1c and 1d.
f is formed. The pin grooves 1e and 1f are not limited to rectangular recessed grooves, but may be U grooves or V grooves. At this time, needless to say, the holding grooves 1c and 1d are formed with high precision.

Here, each pin 2 has a large diameter portion 2c formed at the rear portion of the small diameter portion 2a via a tapered step portion 2b. In the pin 2, the small diameter portion 2a forms a ferrule fiber hole (not shown), and the large diameter portion 2c forms a guide hole (not shown) for guiding the optical fiber to the fiber hole. The pin 3 is formed with a pin hole (not shown) of a ferrule through which the guide pin is inserted.

As shown in FIG. 3, the core 1 having the above-mentioned structure has a lower mold 11 and an upper mold 15, and the mold 1 has the following structure.
It is placed in the No. 0 and used for manufacturing ferrules. Lower mold 1
As shown in FIG. 3, 1 has a base block 12, a first positioning block 13 and a second positioning block 14. The base block 12 has a first positioning block 13 at the front, a second positioning block 14 at the rear, and a support block 12a in the middle.

As shown in FIG. 3, the first positioning block 13 has V grooves (not shown) for arranging the pins 3 on the left and right sides of the upper surface, and a plurality of pins 2 individually arranged between these V grooves. V groove 13a is formed. The second positioning block 14 has a concave groove (not shown) for arranging the core 1 at the center in the width direction and a V groove (not shown) for arranging the pins 3 on both sides of the concave groove. There is.

Here, the upper die 15 is the base block 1
6, the first positioning block 17 and the second positioning block 18, and is configured substantially the same as the lower mold 11.
However, in the first positioning block 17, the groove for arranging the pins 3 is not the V groove but a concave groove, and the V groove for arranging the plurality of pins 2 is not formed. In order to manufacture a ferrule using the mold 10, first, the core 1 is set in the lower mold 11 using the first positioning block 13 and the second positioning block 14.

Next, the upper mold 15 is put on from above, and the mold 10 is closed as shown in FIG. As a result, a ferrule-forming cavity C is formed in the mold 10 by the lower mold 11 and the upper mold 15. Next, the molten resin such as polyphenylene sulfide (PPS) resin or epoxy resin is filled in the cavity C. As a result, the ferrule 20 shown in FIG. 4 corresponding to the shape of the cavity C is molded. Then, after a predetermined time has passed,
The mold 10 is opened and the ferrule 20 which is a molded product is taken out.

The ferrule 20 has a collar portion 20b formed at the rear portion of the main body 20a, a cylindrical portion extending from the approximate center of the main body 20a to the rear side, and an opening 20 formed at the center of the main body 20a.
c is formed. Further, the ferrule 20 has two pin holes 20d on both sides for inserting the guide pins along the longitudinal direction, and a plurality of (eight) fiber holes 20e for inserting an optical fiber are provided between the two pin holes 20d. Has been formed.

At this time, in the closed mold 10, as shown in FIG. 3, one end side of each pin 2 has a V groove 13a and a first groove.
The other end side of each pin 2 is held by the positioning block 17 and the second positioning block 14, 18 via the core 1
Are held respectively. In particular, the pins 2 are
The other end is individually held in the U-shaped holding grooves 1c and 1d formed in the core 1 with high precision as described above. That is,
The core 1 holds the ends of the individual pins 2 with high precision by the holding grooves 1c and 1d.

Therefore, when the ferrule 20 is molded by using the core 1 of this embodiment, the plurality of pins 2 are effectively prevented from moving due to the injection pressure of the synthetic resin at the time of molding, and the plurality of fiber holes 20e are formed. Is molded with high precision. Therefore, by using the core 1, it is possible to manufacture the ferrule 20 with a small connection loss in the optical connector.

As described above, the use of the core 1 improves the holding accuracy of the plurality of pins 2, resulting in an improvement in the forming accuracy of the fiber hole 20e, and the optical connector using the ferrule 20 has a butt end surface polished. In this case, it is possible to obtain an excellent effect that the positions of the plurality of optical fibers bonded and fixed to the plurality of fiber holes 20e do not change even if the polishing amounts are different. For example, with respect to an optical connector in which the butt end faces are polished obliquely, the yield satisfying the criterion that the connection loss is 0.3 dB or less is 50% or less in the above-mentioned conventional technique. On the other hand, 90% or more of the optical connectors using the ferrule manufactured by the manufacturing method of the present invention satisfied the above criteria.

Here, in the core 1, the plurality of pins 2 are individually held by the U-shaped holding grooves 1c and 1d.
1d may be, for example, a V groove as long as it can position the plurality of pins 2 with high accuracy. Also, the core 1 is
As shown in FIG. 1, eight pins 2 are held, but the number may be variously changed according to the application. Next, a second embodiment according to the core of the present invention and the method of manufacturing a ferrule using the core will be described.

As shown in FIG. 5, in the core 5, the plurality of pins 2 described in the above embodiment are held by the pin holders 5a and 5b via the spacers 6 and the two pins 3 are held. ing. As shown in FIGS. 5 and 6, the pin holders 5a and 5b include concave grooves 5c and 5d in which a plurality of pins 2 and spacers 6 are arranged, and rectangular concave grooves that hold the pins 3 on both sides of the concave grooves 5c and 5d. Formed with pin grooves 5e and 5f.

The spacer 6 is used to arrange the plurality of pins 2 in two stages. At this time, as shown in FIG. 6, the recessed grooves 5c and 5d have a plurality of U-shaped holding grooves 5g and 5h for individually holding the plurality of pins 2 formed at the bottom with high precision. However, the holding grooves 5g and 5h may be V grooves as shown in FIG. 7A as long as the pins 2 can be positioned with high accuracy. Similarly, it goes without saying that the spacer 6 may form a V groove 6a that cooperates with the holding grooves 5g and 5h to position the plurality of pins 2 with high accuracy.

As shown in FIG. 8, the core 5 constructed as described above is placed in a mold 30 having a lower mold 31, an upper mold 35 and a first positioning block 39 to manufacture a ferrule. Be used for. The lower die 31 is, as shown in FIG.
It has a base block 32 and a second positioning block 34.

A second positioning block 34 is arranged on the rear side of the base block 32, and the first positioning block 3 is provided.
A support block 32a is arranged between the 9 and the second positioning block 34. Second positioning block 34
Is a groove for arranging the core 5 at the center in the width direction (not shown)
However, V grooves (not shown) for arranging the pins 3 are formed on both sides of the concave groove, respectively.

Here, the upper die 35 is the base block 3
6 and the second positioning block 38, and is configured substantially the same as the lower mold 31. First positioning block 39
As shown in FIG. 8, positioning holes (not shown) for inserting and positioning the tips of the pins 3 on both left and right sides, and the tips of the plurality of pins 2 are individually inserted between these positioning holes. And a positioning hole 39a for positioning are formed in upper and lower two stages.

The first positioning block 39 and the second positioning block 39
Mold 3 with core 5 using positioning block 34
Set to 1 and set 2 in the first positioning block 39.
The ferrule 22 shown in FIG. 9 is manufactured by positioning the tips of the book pins 3 and the plurality of pins 2 and molding the pins in the same manner as in the first embodiment. At this time, the mold 30
As shown in FIG. 8, a cavity C for molding the ferrule 22 is formed by the lower mold 31, the upper mold 35, and the first positioning block 39.

The ferrule 22 manufactured in this way
Has a collar portion 22b formed at the rear portion of the main body 22a, and the rear portion side of the main body 22a is formed into a tubular shape from the center thereof.
An opening 22c is formed in the center of the main body 22a. Further, the ferrule 22 is formed with two pin holes 22d on both sides for inserting the guide pins along the longitudinal direction, and a plurality of fiber holes 22e for inserting an optical fiber between the two pin holes 22d are arranged in upper and lower two stages. Has been formed.

At this time, in the die 30, as shown in FIG. 8, one end side of each pin 2 is located on the first positioning block 3.
9 and the other ends of the pins 2 are respectively held by the second positioning blocks 34 and 38 via the core 5. In particular, the plurality of pins 2 are individually held through the spacers 6 in the U-shaped holding grooves 5g and 5h of the concave grooves 5c and 5d formed on the core 5 with high accuracy as described above. There is. That is, the core 5 holds the plurality of pins 2 in the holding grooves 5g,
5h and the spacer 6 hold them individually with high precision.

Therefore, when the ferrule 22 is molded by using the core 5 of this embodiment, the plurality of pins 2 are effectively prevented from moving due to the injection pressure of the synthetic resin at the time of molding, and the plurality of fiber holes 22e. Is molded with high precision. Therefore, by using the core 5, it is possible to manufacture the ferrule 22 with a small connection loss in the optical connector.

As described above, by using the core 5, the accuracy of holding the plurality of pins 2 is improved. As a result, the molding accuracy of the fiber hole 22e is improved, and the optical connector using the ferrule 22 has a butt end surface polished. In this case, it is possible to obtain an excellent effect that the positions of the plurality of optical fibers bonded and fixed to the plurality of fiber holes 22e do not change even if the polishing amounts are different. For example, with respect to an optical connector in which the butt end faces are polished obliquely, the yield satisfying the criterion that the connection loss is 0.3 dB or less is 50% or less in the above-mentioned conventional technique. On the other hand, 90% or more of the optical connectors using the ferrule manufactured by the manufacturing method of the present invention satisfied the above criteria.

The core 5 includes a plurality of pins 2 and spacers 6
Although it is arranged in two stages above and below through the above, it is needless to say that a plurality of pins 2 can be arranged in three or more stages by increasing the number of spacers 6, and the number of pins 2 per stage is shown in FIG. The number is not limited to eight shown.

[0030]

According to the first to fourth aspects of the present invention, it is possible to provide a core and a ferrule manufacturing method using the core capable of manufacturing a ferrule with a small connection loss in an optical connector.

[Brief description of drawings]

FIG. 1 is a perspective view showing a core and a first embodiment of a ferrule manufacturing method using the core of the present invention.

FIG. 2 is an enlarged front view showing a portion A of the core of FIG.

3 is a cross-sectional side view of the core ferrule of FIG. 1 arranged in a mold for molding.

FIG. 4 is a perspective view of a ferrule molded by the mold of FIG.

FIG. 5 is a front view showing a second embodiment of a core and a ferrule manufacturing method using the core of the present invention.

6 is an enlarged front view showing a portion B of the core of FIG. 5. FIG.

7 is a front view showing a modified example of the core of FIG. 5 in a state corresponding to FIG. 6, showing a modified example (a) of the holding groove and a modified example (b) of the spacer.

8 is a cross-sectional side view of the core of FIG. 5 arranged in a mold for molding a ferrule.

9 is a perspective view of a ferrule molded by the mold of FIG. 8. FIG.

[Explanation of symbols]

1 core 1a, 1b pin holder 1c, 1d holding groove 1e, 1f pin groove 2 pin 2a small diameter part 2b step 2c large diameter part 3 pin 5 core 5a, 5b pin holder 5c, 5d concave groove 5e, 5f pin groove 5g, 5h holding groove 6 spacers 6a V groove 10 mold 11 Lower mold 12 base blocks 12a support block 13 1st positioning block 13a V groove 14 Second positioning block 15 Upper mold 16 base blocks 17 1st positioning block 18 Second positioning block 20,22 ferrule 20a, 22a body 20b, 22b collar part 20c, 22c opening 20d, 22d pin holes 20e, 22e Fiber hole 30 molds 31 Lower mold 32 base blocks 32a support block 34 Second positioning block 35 Upper mold 36 base blocks 38 Second positioning block 39 1st positioning block C cavity

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasushi Kihara             2-6-1, Marunouchi, Chiyoda-ku, Tokyo             Kawa Electric Industry Co., Ltd. (72) Inventor Takashi Shigematsu             2-6-1, Marunouchi, Chiyoda-ku, Tokyo             Kawa Electric Industry Co., Ltd. F-term (reference) 2H036 JA01 LA02 LA05 QA12 QA18                       QA20

Claims (4)

[Claims] 1. A core, wherein a plurality of pins forming a fiber hole of a ferrule are respectively held in a plurality of holding grooves formed in a pin holder. 2. The core according to claim 1, wherein the plurality of pins are held in a plurality of stages on the pin holder via spacers. 3. The core according to claim 2, wherein a retaining groove for retaining the pin is further formed in the spacer. 4. A core in which a plurality of pins forming a fiber hole of a ferrule are held in each of a plurality of holding grooves formed in a pin holder, and a molding pin forming a pin hole through which a positioning pin of a ferrule is inserted. Is placed in a mold, and a synthetic resin is injected into the mold to manufacture the ferrule.