JP4086140B2 - Ferrule for optical connector - Google Patents

Description

[0001]
[Technical field belonging to the invention]
The present invention relates to a resin optical connector ferrule used for a fitting pin positioning type optical connector.
[0002]
[Prior art]
FIG. 9 shows a conventional ferrule 1 for an optical connector. This ferrule for optical connectors (abbreviated as ferrule) 1 corresponds to a ferrule used for a fitting pin positioning type optical connector (JIS C 5981: F12 type multi-core optical fiber connector) generally called an MT connector. An optical fiber hole 4 that opens to the connection end surface 3 at the front portion (left side in FIG. 9B ) of the hollow portion 2 for inserting the optical fiber core wire that opens to the rear end side (right side of FIG. 9B ) . the equipped, with a guide pin holes 5 for positioning on both sides, with the optical fiber Baga id groove 6 facing the optical fiber holes 4 in the optical fiber insertion hollow portion 2, further bonding of the optical fiber fixing The structure is provided with an adhesive filling hole 7 opened on the upper surface of the ferrule for filling the agent, and is a resin-integrated molded product (refer to the conventional example of JP-A-2001-83367). The hollow portion 2 for inserting the optical fiber core wire has a protective boot insertion portion 2a at the inlet side portion.
[0003]
The conventional ferrule 1 is a resin-integrated molded product as described above, and the internal hollow portion composed of the optical fiber core wire insertion hollow portion 2 and the adhesive filling hole 7 communicating with each other has a rear end side and an upper surface side. And is asymmetrical in the vertical direction.
[0004]
[Problems to be solved by the invention]
In the resin molding of the ferrule 1, an optical fiber hole core pin and a guide together with a portion corresponding to the hollow portion 2 for inserting an optical fiber core wire are formed in a cavity of a generally ferrule outer shape formed by an upper die and a lower die of a mold. A mold having a core pin with a pin hole core pin is used, but since the shape of the ferrule 1 is vertically asymmetric, the mold shrinkage rate of the filled resin tends to vary depending on the location, and high dimensional accuracy is ensured by the shrinkage strain. It is not always easy.
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical connector ferrule capable of easily obtaining a high-precision optical connector ferrule by eliminating a factor of deterioration in accuracy during resin molding. To do.
[0006]
[Means for Solving the Problems]
The present invention that solves the above-mentioned problem is provided with an optical fiber hole in the front portion of the hollow portion for inserting the optical fiber core opening on the rear end side of the ferrule, and opened on the upper surface of the ferrule so that the hollow portion for inserting the optical fiber core wire is provided. In the ferrule for optical connector made of resin of the fitting pin positioning method with the adhesive filling hole leading to the front side space,
A guide hole having an optical fiber guide groove facing the entrance of the optical fiber hole in the bottom hole is provided on the lower surface side of the ferrule so as to face the adhesive filling hole on the upper surface side and form a vertical through space. The member is fitted and fixed, and the guide member is resin-molded separately from the ferrule .
[0008]
According to a second aspect of the present invention, in the ferrule for an optical connector according to the first aspect, a shallow recess is formed around the bottom hole on the lower surface of the ferrule, and a flange portion that fits into the recess is formed on the lower surface side of the guide member. The optical fiber guide groove and the optical fiber hole are positioned by forming and positioning in the vertical direction so that the flange portion is accommodated in the recess.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
1 is an exploded perspective view of an optical connector ferrule 11 according to an embodiment of the present invention before assembly, FIG. 2 is a view of the optical connector ferrule 11 of FIG. 1 viewed from below, and FIG. 3 is an optical connector in an assembled state. 4 is a plan view of the ferrule 11, FIG. 4 is a cross-sectional view taken along line AA in FIG. 3, and FIG. 5 is a cross-sectional view taken along line BB in FIG. As shown in these drawings, the ferrule 11 for an optical connector as a whole corresponds to a ferrule used for a fitting pin positioning type optical connector (JIS C 5981: F12 type multi-fiber optical fiber connector) called an MT connector. The front portion of the hollow portion 12 for inserting the optical fiber core wire, which is made of a resin having a substantially rectangular shape and opens to the rear end side of the ferrule (the right side in FIGS. 3 and 4) (left in FIGS. 3 and 4) 1), optical fiber holes 14 opened in the connection end face 13 are provided, guide pin holes 15 for positioning are provided on both sides, and further opened on the upper surface of the ferrule to the front of the hollow part 12 for inserting the optical fiber core wire. A square adhesive filling hole 17 that leads to the side space is provided. The inlet portion 14a of the optical fiber hole 14 is tapered (conical surface) so that the optical fiber can be easily inserted. The optical connector ferrule 11 is attached to a tape core (optical fiber tape core). The entrance side portion of the hollow portion 12 for inserting the optical fiber core wire is a protective boot insertion portion 12a. Reference numeral 18 denotes a buttocks.
[0010]
In the present invention of this embodiment, a bottom hole 20 is provided on the lower surface side of the ferrule 11 so as to form an upper and lower through space 19 facing the adhesive filling hole 17 on the upper surface side. In this embodiment, a guide member 21 which is separately resin-molded having an optical fiber guide groove 21a facing the inlet 14a of the optical fiber hole 14 is fitted into this bottom hole 20 and fixedly bonded thereto. The guide member 21 has a flange portion 21 b on the lower surface side. On the other hand, the guide member 21 has a shallow recess 22 around the bottom hole 20 on the lower surface of the ferrule 11, and the flange portion 21 b of the guide member 21 is formed in the recess 22. It fits. As a result, the guide member 21 is firmly fixed to the bottom hole 20, and positioning in the vertical direction is performed with high accuracy, so that the positional accuracy of the optical fiber guide groove 21a with respect to the optical fiber hole 14 can be easily secured.
[0011]
When manufacturing the ferrule 11, the ferrule body 11 ′, which is a portion of the ferrule 11 excluding the guide member 21, is resin-molded, and the guide member 21 that is separately resin-molded is fitted into the bottom hole 20 of the ferrule body 11 ′. Adhere and fix. As a resin material used for molding the ferrule body 11 ′ and the guide member 21, a resin that is the same material and is suitable for precision molding, for example, an epoxy resin containing a silica filler may be used. Moreover, for example, an epoxy resin adhesive can be used as an adhesive that adheres the guide member 21 to the bottom hole 20. The guide member 21 may be simply fitted into the bottom hole 20 without being fixed in advance with an adhesive, and the guide member 21 may be fixed to the bottom hole 20 with an adhesive filled from the adhesive filling hole 17. it can.
[0012]
Since the ferrule body 11 'has a bottom hole 20 facing the adhesive filling hole 17 and a vertical through space 19 is formed, the conventional ferrule having the adhesive filling hole 7 simply opened on the upper surface shown in FIG. Compared with 1, the shape and weight balance are close to vertical symmetry. The ferrule body 11 ′ is formed by pouring molten resin into a cavity formed in a mold composed of an upper mold, a lower mold, and a core. However, as described above, the shape and weight balance are close to vertical symmetry. The molding shrinkage rate of the poured resin is rarely uneven. Therefore, there is little shrinkage distortion and it is easy to ensure high dimensional accuracy.
[0013]
The shapes of the adhesive filling hole 17 and the bottom hole 20 are preferably symmetric as much as possible in order to make the molding shrinkage rate uniform and eliminate the shrinkage strain. However, even if the shape itself is not vertically symmetric, the weight balance is up and down. If it is symmetrical, it is easy to obtain a uniform molding shrinkage, and therefore it is preferable to make the weight balance as close to vertical symmetry as possible. The adhesive filling hole 17 of the embodiment has the left and right side surfaces as tapered surfaces 17a, and the upper surface side is widened. The widened portion corresponds to the recess 22 on the lower surface side, and the weight balance between the upper and lower sides is made uniform. In order to contribute.
[0014]
FIG. 6 shows a state in which the ferrule 11 is attached to the tape core wire 25. The coating of each optical fiber core 25 ′ of the tape core 25 passed through the protective boot 26 is removed, and the bare fiber 25a from which the coating has been removed is inserted into the optical fiber hole 14 previously injected with an adhesive, and fixed. The optical fiber core wire 25 ′ is fixed by filling the adhesive 27 from the adhesive filling hole 17. Thereafter, the end face 13 is polished.
[0015]
In the above embodiment, the guide member 21 is provided with the flange portion 21a and has many advantageous surfaces as described above. However, like the ferrule 11A shown in FIG. 7, the guide member 21A having no flange portion is used. May be. In this case, the recess 22b is not required in the ferrule body 11′A, and the top and bottom can be made completely symmetrical as shown in the drawing, which is preferable in terms of formability of the ferrule body. In this case, the guide member 21A is positioned and fixed with high accuracy in the bottom hole 20A, taking care not to impair the positional accuracy of the optical fiber guide groove 21a with respect to the optical fiber hole 14.
[0016]
Further, like the ferrule 11B shown in FIG. 8, the hollow portion 12 for inserting the optical fiber core wire of the ferrule body 11′B may have a shape having a lateral hole portion 12b that enters the front side from the adhesive filling hole 17. In this case, the portion 21c of the optical fiber guide groove 21a of the guide member 21B enters the lateral hole portion 12b. The bottom hole is indicated by 20B.
[0018]
The ferrule 11 of the above embodiment is applied as a ferrule for a one-dimensional optical connector in which optical fiber holes 14 are arranged in a horizontal row, but for a two-dimensional optical connector in which optical fiber holes are arranged in a vertical direction and a horizontal direction. It can also be applied as a ferrule.
When applied to a two-dimensional optical connector ferrule, the same effect as that of a one-dimensional optical connector ferrule can be obtained easily. However, in the case of a two-dimensional optical connector ferrule, high precision is obtained. Is more difficult than in the case of a ferrule for a one-dimensional optical connector. Therefore, there is a great advantage in that a bottom hole for forming a vertical through space is provided to enable high-precision molding.
[0019]
The ferrule of the present invention is usually applied to a ferrule for a multi-fiber optical connector, but can also be applied to a single-fiber optical connector. In addition, as in the embodiment, the rear end portion of the ferrule is usually formed with a square flange portion 18 that is slightly larger than the cross section of the intermediate portion, but the shape of the flange portion may be different from this, It is also possible not to form the collar.
[0020]
【The invention's effect】
According to the present invention, in the optical pin ferrule for resin optical connector of the fitting pin positioning method, the bottom surface of the ferrule is provided with the bottom hole that forms the upper and lower through space facing the adhesive filling hole on the upper surface side. The shape or weight balance of the ferrule is close to vertical symmetry, which makes it possible to reduce the molding shrinkage when the ferrule is resin-molded, and to easily obtain high accuracy.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an optical connector ferrule of the present invention before assembly.
FIG. 2 is a view of the optical connector ferrule of FIG. 1 as viewed from below.
3 is a plan view of the assembled optical connector ferrule of FIG. 1; FIG.
4 is a cross-sectional view taken along the line AA in FIG. 3;
5 is a cross-sectional view taken along the line BB in FIG.
6 is a view showing the ferrule of FIG. 5 attached to a tape core wire.
FIG. 7 is a cross-sectional view of an optical connector ferrule according to another embodiment of the present invention (corresponding to FIG. 4).
FIG. 8 is a cross-sectional view of an optical connector ferrule according to still another embodiment of the present invention (corresponding to FIG. 4).
9A and 9B show a conventional ferrule for an optical connector, in which FIG. 9A is a perspective view and FIG. 9B is a cross-sectional view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11, 11A, 11B Ferrule 11 ', 11'A, 11'B for optical connectors 12 Ferrule main body 12 Optical fiber core wire hollow part 12a Protective boot insertion part 12b Side hole part 13 Connection end face 14 Optical fiber hole 15 Guide pin hole 17 Adhesive filling hole 18 ridge 19 upper and lower through space 20, 20A, 20B bottom hole 21, 21A, 21B guide member 21a optical fiber hole guide groove 21b flange 22 recess

Claims (2)

An optical fiber hole is provided in the front portion of the hollow portion for inserting the optical fiber core wire that opens to the rear end side of the ferrule, and an adhesive filling hole that opens in the upper surface of the ferrule and communicates with the front space of the hollow portion for inserting the optical fiber core wire. In the ferrule for optical connector made of resin with a fitting pin positioning method with
A guide hole having an optical fiber guide groove facing the entrance of the optical fiber hole in the bottom hole is provided on the lower surface side of the ferrule so as to face the adhesive filling hole on the upper surface side and form a vertical through space. A ferrule for an optical connector, wherein a member is fitted and fixed, and the guide member is resin-molded separately from the ferrule. A shallow recess is formed around the bottom hole on the lower surface of the ferrule, a flange portion that fits into the recess is formed on the lower surface side of the guide member, and the flange portion is accommodated in the recess. 2. The ferrule for an optical connector according to claim 1 , wherein the optical fiber guide groove and the optical fiber hole are positioned by performing vertical positioning .

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