JP2007212600A - Molding die for optical connector and ferrule for optical connector manufactured with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding die for optical connector in which a molding pin is not moved by the pressure of resin when the resin is ejected and the optical connector is accurately manufactured, and to provide a ferrule for optical connector manufactured with the molding die for optical connector. <P>SOLUTION: The molding die for optical connector is used to manufacture a ferrule for the optical connector which has a plurality of optical fiber through holes for arranging optical fibers at the front end part and a boot part at the rear end part formed by injection molding. The molding die for optical connector is characterized in that the molding die is composed of a lower molding die, an upper molding die and a core arranged in the internal space of the molding dies, the core is composed of a plurality of molding pins for forming the optical fiber through holes and a pin arraying member for arraying and holding the plurality of molding pins, and the molding pins are arrayed, held and arranged by being inserted into pin inserting holes formed on the pin arraying member by drilling. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical connector molding die for manufacturing an optical connector ferrule by injection molding and an optical connector ferrule manufactured thereby.

  In general, this type of optical connector ferrule 1 is provided with a plurality of optical fiber insertion holes 2 and guide pin holding holes 3 opened at the tip, as shown in FIG. An optical fiber which is formed so that the rear portion of the optical fiber insertion hole 2 (not shown) communicating with the optical fiber insertion hole 2 faces the inner space 4 ′ visible from the hole 4 and further communicates with the inner space 4 ′ at the rear end. A tape core wire introduction hole 5 is formed.

FIG. 4B shows a state where the optical connector ferrule 1 is attached to the end of the optical fiber ribbon 6. This attached state is assembled as follows.
First, the coating at the tip of the optical fiber ribbon 6 is removed to expose the optical fiber, and the coating of the end from the optical fiber ribbon introduction hole 5 formed at the rear end of the optical connector ferrule 1 is performed. The exposed optical fiber is inserted into the optical fiber insertion hole 2 while the optical fiber tape core wire 6 from which is removed is inserted. Thereafter, the adhesive 7 is injected from the window hole 4 into the internal space 4 ′, and the optical fiber ribbon 6 and the optical connector ferrule 1 are fixed together. Thereafter, a boot (not shown) is arranged between the optical fiber tape core wire introduction hole 5 and the optical fiber tape core wire 6, and the optical fiber tape core wire 6 is mechanically strengthened. Further, the end face 8 of the optical fiber protruding from the end face 2 ′ of the optical fiber insertion hole 2 is polished, if necessary, at a non-right angle with respect to the axis of the optical fiber in order to reduce the reflected light from the end face. .

Further, a method has been proposed in which the optical connector ferrule 1 and the boot are integrally formed of the same material. (For example, see Patent Document 1)
As shown in FIG. 5, the ferrule 1 for an optical connector disclosed in Patent Document 1 is formed with a boot portion 9 so that a rear end portion of the ferrule 1 for the optical connector is marked.
Such an optical connector ferrule 1 is manufactured by an injection molding method in which a molding resin is injected into a molding die.

  FIG. 6 shows an example of a conventional optical connector molding die 20, which includes a lower die 21, an upper die 22, a core 25 by a pin alignment member 24 that aligns and holds a plurality of molding pins 23, a guide. It is constituted by a hole forming pin 26 or the like. The lower mold 21 has a recess 21 ′ that matches the outer shape of the upper half of the optical connector ferrule 1 manufactured on the upper surface, and the upper mold 22 is the lower half of the optical connector ferrule 1 manufactured on the lower surface. It has a recess 22 'that matches the outer shape of the. Further, a molding pin holding groove 27 and a guide hole forming pin holding groove 28 are formed in the front part of the lower mold 21 and / or the front part of the upper mold, and thereby the molding pin support part 29 is formed. Is formed.

  In order to manufacture the optical connector ferrule 1 using the optical connector molding die 20, the pin alignment member 24 is placed in the recess 21 ′ of the lower die 21 and the molding pin 23 is placed in the molding pin holding groove 27. Further, the guide hole forming pin 26 is placed on the guide hole forming pin holding groove 28, and then the upper mold 22 is put on these pins. A resin injection space is formed around the inner wall of the mold formed by the recess 22 ′ and the recess 21 ′ of the lower mold 21, the molding pin 23, the pin alignment member 24, and the like. Then, the ferrule 1 for optical connectors is formed by inject | pouring resin from the resin injection port which is not illustrated in this resin injection space, and making it harden | cure.

JP 2001-074973 A

  As shown in FIGS. 4 and 5, the optical connector ferrule 1 is constituted by a resin portion and an internal space portion. The space portion includes the window hole 4, the optical fiber tape core wire introduction hole 5, the guide pin holding hole 3, and the like. There is a difference in molding shrinkage between the resin portion and the space portion. Since the optical fiber tape core introduction hole 5 has a boot, it is designed to be about 0.5 mm larger than the width of the optical fiber ribbon used and about 1.0 mm larger than the thickness of the optical fiber ribbon 6. It was. Therefore, a large shrinkage difference has occurred between the front end side and the rear end side with the window hole 4 as a boundary.

  When the difference in shrinkage occurs as described above, the pitch of the guide pin holding holes 3 listed as one of important dimensions of the optical connector ferrule 1 changes between the front end side and the rear end side of the optical connector ferrule 1. come. The pitch of the guide pin holding holes 3 is small on the front end side with a large amount of resin, and the pitch of the guide pin holding holes 3 is large on the rear end side with a large space. That is, the two guide pin holding holes 3 are not parallel to each other, making it difficult to obtain good optical characteristics. Further, because of the difference in contraction due to the structure of the ferrule 1 for optical connectors, it becomes very difficult to obtain molding conditions for making the guide pin holding holes 3 parallel.

The conventional pin alignment member 24 is divided into two parts as shown in FIG. 7, and the assembly is performed as shown in FIG. 8 with the molding pin 23 sandwiched between the two pin alignment members 24a and 24b. In the case of the ferrule 1 for an optical connector in which the general boot portion 9 is not integrally formed, the pin alignment member 24 ′ constituting the boot portion 9 becomes large, so that a sufficient mold thickness can be secured and sufficient component strength can be obtained. It is done.
However, in the case of the optical connector ferrule 1 in which the boot portion 9 is integrally formed, the fiber insertion port 9 ′ becomes very small, and therefore the size of the fiber insertion port forming portion in the pin alignment member is small. Furthermore, because of the split structure, the fiber insertion port forming portion of the small pin alignment member must be divided into two, and the mold part is very thin and small. As a result, this portion of the molding die is insufficient in strength and easily damaged, and processing becomes difficult, so that the manufacturing cost of the molding die increases.

  Further, when the optical connector ferrule 1 is molded using the two-pin split pin alignment members 24 a and 24 b as disclosed in Patent Document 1, the molding pin 23 moves between the molding pin 23 and the molding pin 23. Then, there is a possibility that the arrangement of the forming pins 23 is disturbed. If the arrangement of the molding pins 23 is disturbed, the production accuracy of the optical connector ferrule 1 which is a molded product is deteriorated. In the worst case, the molding pin 23 may not fit in the mold and the mold may be damaged.

  The present invention has been made in view of this point, and manufactured by injection molding an optical connector ferrule having a plurality of optical fiber insertion holes for arranging optical fibers at the front end portion and a boot portion formed at the rear end portion. The optical connector molding die is composed of a lower die, an upper die, and a core disposed in an internal space of these molds, and the core is the optical die. It is composed of a plurality of forming pins for forming fiber insertion holes and a pin aligning member for aligning and holding these forming pins, and the forming pins are aligned and held by being inserted into pin insertion holes formed by excavation in the pin aligning member. It is characterized by being arranged.

  In the present invention, since the forming pins are aligned and held by being inserted into the pin insertion holes formed by excavation in the pin alignment member, the forming pins are mechanically firmly fixed. As a result, the forming pins 23 and the forming pins are fixed. When the resin enters between 23, the molding pin 23 does not move due to the flow of the resin, the arrangement of the molding pins 23 is not disturbed, and the ferrule for optical connectors can be manufactured with high accuracy. .

  Hereinafter, the present invention will be described in more detail with reference to FIGS. 1 to 3 illustrating the present embodiment. FIG. 1 shows a perspective view of an optical connector molding die 30 in the present embodiment. As in the conventional example shown in FIG. 6, the optical connector molding die 30 is a core 25 formed by a pin alignment member 24 that aligns and holds a lower die 21, an upper die 22, and a plurality of molding pins 23. The guide hole forming pin 26 is used.

  The present embodiment is greatly different from the conventional example shown in FIG. 6 in that, as shown in FIG. 2, the pin alignment member 24 is integrally formed without being divided into two parts, and the boot portion 9 is formed. A pin insertion hole 23a slightly larger than the outer diameter of the molding pin is cut and formed at the end of the pin alignment member 24 'to be cut by a cutting drill or the like, and the direction of the pin insertion hole 23a at the end 24' of the pin alignment member 24 ' A guide pin insertion hole 26a slightly larger than the outer diameter of the guide hole forming pin 26 is cut and formed by a cutting drill or the like in the same direction as the guide hole forming pin 26. Further, the molding pin 23 and the guide hole forming pin are formed in these holes 23a and 26a. 26 is inserted and arranged.

  Here, these holes 23a, 26a are configured to have a value slightly larger than the diameter of the pin used, for example, the hole diameter is 0 μm to 5 μm larger than the diameter of the pin used. Almost no molding resin enters the gaps between the pins 23 and 26. As a result, a highly accurate ferrule for an optical connector can be manufactured without disturbing the arrangement of the molding pins 23 during resin molding.

  The outer diameter of the pin aligning member 24 ′ for constituting the boot portion 9 is the same as the inner diameter of the boot portion 9 of the optical connector ferrule 1 when it is molded and commercialized. This size is configured to be slightly larger than the outer diameter of the optical fiber ribbon. For example, this size is increased by 0.1 mm with respect to the thickness and width of the optical fiber ribbon used. For example, assuming that the outer diameter of the optical fiber ribbon is 0.3 mm thick and 1.2 mm wide, the inner diameter of the boot portion is about 0.4 x 1.3 mm.

  In general, in the ferrule 1 for an optical connector in which the boot portion 9 is formed integrally, the inner diameter of the boot portion 9 is very small. In the present embodiment, a pin insertion hole 23a is formed at the tip of the pin alignment member 24 ′ constituting the boot portion 9. Therefore, the mechanical strength of this portion is greatly increased compared to the conventional structure. For this reason, there is less concern about damage to the mold.

Usually, since the optical fiber interval of the optical fiber ribbon is 250 μm, the pin insertion hole 23 a needs to have a diameter of less than 250 μm. If the pin insertion hole 23a is close to 250 μm, the thickness of the mold between the pin insertion hole 23a and the pin insertion hole 23a becomes very thin, and the pin insertion hole 23a cannot be maintained. Therefore, the pin insertion hole 23a is desirably 220 μmφ or less.
Further, since the outer diameter of the optical fiber is usually about 125 μmφ, the pin insertion hole 23 a needs to be larger than the diameter 125 μm. If the inner diameter of the pin insertion hole 23a is close to 125 μm (= the outer diameter of the molding pin is close to 125 μm), the inner diameter of the optical fiber insertion hole 2 of the ferrule becomes close to 125 μmφ, and fiber insertion work becomes difficult. Therefore, the inner diameter of the optical fiber insertion hole 2 is desirably 150 μm or more.
That is, the diameter D of the pin insertion hole 23a is 150 μm ≦ D ≦ 220 μm
It is desirable that

FIG. 3 shows the ferrule 1 for an optical connector molded by the molding die according to the above embodiment.
The ferrule 1 for an optical connector according to the present embodiment is configured such that the size of the window hole 4 is small. The window hole 4 is provided for inserting the optical fiber along the guide groove while visually checking the optical fiber when inserting the optical fiber, and for injecting an adhesive. If the window hole 4 is made smaller, the space in which the window hole 4 is formed becomes smaller. However, if the window hole 4 is too small, it is difficult to visually confirm, so that the optical fiber insertion workability becomes difficult. Therefore, the space for forming the window hole 4 is reduced by making the window hole 4 as small as possible within the range in which the optical fiber can be inserted.

Specifically, the size of the window hole 4 in the longitudinal direction is 0.5 mm to 2.0 mm which allows the optical fiber to be visually confirmed, and the size of the window hole 4 in the width direction is relative to the width of the optical fiber tape to be used. The design is 0.1 mm larger. The guide groove 2 a is also shortened according to the size of the window hole 4.
Furthermore, the space from the rear end portion of the boot portion 9 to the window hole 4 is shortened by designing the position from the end surface (front end surface) of the optical connector ferrule 1 to the window hole 4 to be long. It is desirable that the length from the end face (tip face) of the optical connector ferrule 1 to the window hole 4 is 3.0 mm or more and that the window hole 4 is not in contact with the flange 1a. The inner diameter of the boot portion 9 is continuously extended to the same diameter up to the position of the window hole 4.

  The optical connector ferrule 1 of this embodiment increases the amount of resin constituting the optical connector ferrule 1 by making the space formed by the inner diameters of the window hole 4 and the boot portion 9 as small as possible, thereby increasing the ferrule for the optical connector. 1 is characterized by equalizing the entire shrinkage.

With the structure as described above, the space portion of the optical connector ferrule 1 in the above embodiment is less than half the space portion of the conventional optical connector ferrule 1, and molding shrinkage with the window hole 4 as a boundary is reduced. The difference is greatly reduced, and a highly accurate optical connector ferrule 1 can be easily obtained.
Further, the manufacturing cost can be reduced by integrally forming the boot portion 9.

The disassembled perspective view which shows the molding die for optical connectors in one Embodiment of this invention. The principal part disassembled perspective view of the components in FIG. The ferrule for optical connectors of this invention manufactured with the shaping | molding die for optical connectors of FIG. 1 is shown, A is a cross-sectional view, B is a longitudinal cross-sectional view. (A) is a perspective view showing an example of a conventional ferrule for an optical connector, and (b) is a perspective view of the optical connector ferrule in use. The longitudinal cross-sectional view which shows the other example of the conventional ferrule for optical connectors. The disassembled perspective view which shows an example of the shaping | molding die for conventional optical connectors. The disassembled perspective view which shows the other example of the shaping | molding die for conventional optical connectors. The perspective view when FIG. 7 is assembled.

Explanation of symbols

1 Ferrule for optical connector
1a 鍔 2 Optical fiber insertion hole 2 'End surface 3 Guide pin holding hole 4 Window hole 4' Internal space 5 Optical fiber tape core wire introduction hole 6 Optical fiber tape core wire 7 Adhesive 8 End surface 9 Boot portion 9 'Fiber insertion port 20 Optical connector molding die 21 Lower die 22 Upper die 23 Molding pin 24 Pin alignment member 24a Pin insertion hole 25 Core 26 Guide hole forming pin 26a Guide pin insertion hole 27 Molding pin holding groove 28 Guide hole forming Pin holding groove 29 Molding pin support 30 Molding mold for optical connector

Claims (5)

  An optical connector molding die for manufacturing an optical connector ferrule having a plurality of optical fiber insertion holes for arranging an optical fiber at a front end portion and a boot portion formed at a rear end portion by injection molding, The connector molding die is composed of a lower die, an upper die, and a core disposed in an internal space formed by these molds, and the core includes a plurality of molding pins for forming the optical fiber insertion hole and these. An optical connector comprising: a pin aligning member for aligning and holding the forming pin, wherein the forming pin is arranged and held by being inserted into a pin insertion hole formed by excavation in the pin aligning member. Mold for molding.   An optical connector ferrule, which is molded with the optical connector molding die according to claim 1.   3. The optical connector for an optical connector according to claim 2, wherein the inner diameter of the boot portion is 0 to 0.2 mm larger than the outer diameter of the optical fiber ribbon tape inserted therein. Ferrule.   It has a plurality of optical fiber insertion holes for optical fiber placement at the front end, a boot portion is formed at the rear end, a window hole is formed at the upper side, and the inner diameter of the boot portion continues to the position of the window hole. The ferrule for an optical connector according to claim 3, wherein the ferrule is configured to extend to the same diameter.   The size of the window hole is 0.5 mm to 2.0 mm in the same direction as the axis of the optical fiber insertion hole, and is formed at a distance of 3.0 mm from the ferrule end face. 5. A ferrule for optical connectors according to 4.

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