JPS63261206A - Connector for optical fiber and its production - Google Patents

Abstract

PURPOSE:To obtain an inexpensive connector for optical fiber having good working function by providing an opening extending in the longitudinal direction to plastic parts above a side wall of an inserting hole of optical fiber formed on said plastic parts. CONSTITUTION:Plastic parts 4 is attached to the center of a connecting base plate 3 and a V-shaped grooves 10 for fixing an optical fiber core 1 are formed on both ends of the upper surface of the base plate 3. Further, an inserting hoe 5 for the optical fiber 2 and an opening extending in the longitudinal direction above a side wall of the hole 5 are provided to the parts 4. When optical fibers 2 are to be connected by this constitution the clad of the optical fiber core 1 is removed, then fibers 2 are inserted into left and right holes 5 and butted, and cores 1 are fixed with an instantaneous adhesive. Then, the instantaneous adhesive is applied to both ends of the holes 5 and a refractive index- matching agent is injected from the opening 6. Thereafter, a silicone adhesive or an ultraviolet setting agent is filled through an aperture for the protection of the cores, and the connected part is closed tightly after attaching a cover thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a small and simple optical fiber connector and a method for manufacturing the same.

(Prior Art) Conventionally, as methods for simply connecting optical fibers, there are the groove connection method and the sleeve method. ■The groove shape is a method in which a V-groove 10 is provided on the connector board 3, the optical fibers 2 are aligned, fixed with a holding plate 11, and hardened with adhesive, as shown in Fig. 11(a). In order to achieve accurate axis alignment, it is necessary to apply uniform pressure using a presser plate, which has the drawback of requiring operator skill.

In the sleeve method, as shown in Fig. 11, etc., the connector board 3
A sleeve 1 has a large number of alignment holes 5' arranged in a row.
The second method is to insert the optical fiber 2 until the end faces abut each other. This method does not have good workability because an optical fiber with a very small diameter is inserted into a hole with a similar inner diameter. Therefore, efforts have been made to make the ends of the holes tapered.

However, taper processing has the disadvantage of increasing costs.

In addition, the inside of the sleeve is usually filled with a refractive index matching agent to prevent optical transmission loss due to reflection at the end face of the optical fiber, but it is difficult to inject and hold the matching agent, and the matching agent is placed on the side of the hole. Efforts have been made, such as providing an injection port, but this has the disadvantage of increasing processing costs.

(Problems to be Solved by the Invention) The present invention eliminates the drawbacks of the hole shape and workability of conventional optical fiber splicers, and provides a compact and inexpensive optical fiber splicer with good splicing workability. and its manufacturing method.

(Means for Solving the Problems) The optical fiber insertion hole in the optical fiber connector of the present invention can be easily fabricated in a pre-processed plastic part with an opening above the side wall of the hole. It has been made possible. This hole machining can easily be done by pressing a pin with a cross-sectional shape equivalent to an optical fiber onto the pointed part using the flat surface of a heated heater. This is done by embedding it in a component, cooling it, and then pulling out the pin in the longitudinal direction.

Such a processing method has not existed in the past, and by using this processing method, a hole with an opening in the side wall of the hole can be easily formed.

Conventionally, an opening has been provided in the side wall of the hole, but the opening is a round hole orthogonal to the hole, and does not extend over the entire longitudinal direction as in the present invention.

In addition, the processing method used in the manufacturing method of the optical fiber connector of the present invention softens the sharp parts of the plastic and causes it to flow plastically, so that flow also occurs in the longitudinal direction of the pin, resulting in a hole being machined. The shape has a smoothly changing curvature at both ends. Conventionally, a hole with such an end shape is
could not be formed.

(Example 1) FIG. 1 is a diagram explaining the first example of the present invention,
1 is a coated optical fiber, 2 is an optical fiber, 3 is a connector board, 4 is a plastic part, and 6 is an opening provided above the plastic part 4.

FIG. 2 is a perspective view showing the structure of the plastic part 4, and 5 is a hole for inserting an optical fiber. As shown in FIG. 1, a plastic part 4 having a hole (described later) is attached to the center of the connector board 3. Grooves 10 for positioning and fixing the optical fiber core 1 are formed at both ends of the upper surface of the connector board 3. To connect optical fibers using this connector, first remove the coating of one optical fiber core 1, insert the optical fiber 2 with a shaped end face into the hole 5, and attach the optical fiber core with instant adhesive. Fix it. Next, the other optical fiber 2 is inserted through the hole on the opposite side, and the optical fiber core wire is similarly fixed. Then, instant adhesive is applied to both ends of the hole, and a refractive index matching agent is injected through the opening 6 on the top surface.

Then, to protect the optical fiber, the gap is filled with silicone adhesive or ultraviolet curable adhesive, a cover is attached, and the connection is sealed to complete the process. When using an ultraviolet curing adhesive, if the cover is made transparent, it can be cured by irradiating ultraviolet light after covering.

FIG. 3 is a perspective view showing an example of the structure of the cover 7. FIG.

The hole in the center is an inlet for filling adhesive. With this structure, the filling adhesive can be injected after the cover is attached. The injected adhesive flows outward through the gap between the connector board and the cover, the gap between the optical fiber sheath and the groove, etc., and expels air to the outside, so the optical fiber does not have any cavities around it. It ends up being wrapped in adhesive without it.

Next, a method for forming an optical fiber insertion hole in the plastic part 4 is shown in FIGS. 4(a), (5), and 5(a).

This will be explained using FIGS. 8(b) to 8(a) and ((f)).

In FIGS. 4 and 5 to 8, 8 is a pin made of a heat-resistant material, and 9 is a heater. As shown in FIG. 4(b), the pin 8 is placed in contact with the plane above the heater 9, and when the heater 9 is heated, the pin 8 is placed in contact with the plane above the heater 9. When the plastic part 4 is pressed from above, the top (projection) of the plastic part 4 comes into contact with the pin 8 and softens, and the pin 8 bites into the plastic part 4.

Figures 5(a) and 8(a) to 8(a) and (b) show the change in this state step by step, and (a) shows the change in the fourth state.
The figure shows the state seen from the front, and (b) shows the state seen from the right in FIG.

By further pushing the plastic part 4 from the state where the tip of the plastic part 4 is in contact with the surface of the heater 9 [Fig. 7 (a), (b):], the resin will also go around to the back side of the pin 8. However, due to viscosity, a small gap remains at the contact area between the pin 8 and the surface of the heater 9.

Also, in this process, the tip of the plastic part 4 is pushed away and flows plastically in the longitudinal direction of the pin 8, so that the buried portion of the pin 8 increases.

After the plastic part 4 has been pushed in by an appropriate amount in this manner, when the plastic part is lifted, the softened portion of the plastic part cools and hardens.

You may want to let it cool before lifting. Thereafter, by pulling out the pin 8 in the axial direction, a required hole is formed.

In the example shown in FIG. 4, one end of the pin 8 is thickened to facilitate this pulling operation.

In the example described above, the heater 9 is fixed and the plastic part 4 is pressed against it, but of course the heater 9 may be moved or the arrangement may be reversed.

Alternatively, the pins 8 may be arranged vertically. In that case, there is no risk that the hole in the middle of hardening will be deformed due to the gravity applied to the pin 8.

The shape of the optical fiber insertion hole 5 in the plastic part 4 shown in FIG. 2 is located on an inclined surface, and the edges actually sag and become smooth due to the flow of resin.
A portion is formed that will serve as a guide when attempting to insert the optical fiber end.

FIG. 9 is a diagram illustrating the guiding effect at the end of the hole when inserting the optical fiber. In FIG. 2, the bottom surface of the end of the hole is drawn to be flat in the longitudinal direction, but in reality, as shown in FIG. 9, it becomes a smooth curve, albeit to varying degrees. The reason for this shape is that the flow of the plastic ivy is inhibited in the portion that is in contact with the optical fiber. In either case, when trying to insert the optical fiber end, sliding the optical fiber downward from above will cause it to get caught at the bottom of the hole, so by moving the optical fiber in the axial direction, the light can be removed. Fibers are easily inserted. However, if the bottom is curved, it will be less likely to get caught and the guide will be more effective. This sag at the edge of the hole occurs not only on the bottom surface but also over the entire circumference of the hole, and this also provides a guiding effect when an optical fiber is inserted. Furthermore, the surface of the optical fiber is less likely to be damaged by contact.

Although this embodiment has been described as a single-core connector, it is also possible to apply it to a multi-core connector by arranging a plurality of pins.

(Example 2) In Example 1, the connector board and the plastic parts were separate parts, but FIG. 10 shows an example in which they are integrated. In this case, the optical fiber insertion hole may be fabricated by the method described above after manufacturing it as a single component by a molding method. Furthermore, when forming the hole, the positioning accuracy can be improved by fitting the thick end of the pin shown in FIG. 4 with the groove 2 on the connection board. Furthermore, since there is no need to assemble parts, manufacturing becomes easier.

In addition, since the connector board is manufactured by a molding method, the 10th
As shown in the structure shown in the figure, the space around the optical fiber that needs to be filled with adhesive can be made smaller, and the shape that facilitates the insertion of the optical fiber can be created without being subject to cost constraints. You can choose to. In this case, as in the previous example, the hole is formed by pushing a pin into the protrusion, so it is necessary to create a protrusion in the area where the hole is to be formed during mold shaping. , illustration is omitted in FIG.

Further, in this embodiment, protrusions are provided on both sides of the connector board, which serve as guides for mating the cover. Therefore, the cover in this embodiment has a shape that fits between both of the protrusions. If a semicircular groove is formed in the part that corresponds to the core wire covering part, similarly to the connector board, the gap between the connector board and the cover will be reduced. As described above, the adhesive may be injected through a hole in the cover, but it is also possible to apply a large amount of adhesive and cover the lid. This also applies to the previous embodiment.

(Effects of the Invention) As explained above, the present invention enables the insertion hole for optical fiber positioning to be easily formed into a desired shape, and it is possible to realize an optical fiber connector at low cost and with good workability. This will help popularize communication systems using optical fibers.

Note that the holes formed according to the present invention can be used not only for connecting optical fibers, but also for connecting optical fibers and light sources (semiconductor lasers and LEDs).
It can be used for fixing the optical fiber at the coupling part between the optical fiber and the light receiving element. Conventionally, a groove in the shape of a letter ``■'' or the like has been used in such a portion, and the optical fiber has been placed there, pressed down with a plate from above, and fixed by adhesion. However, there is a drawback that the shape cannot be made too small for convenience of work. In the present invention, 1
Since a hole with a length of about mm can be easily made, it is useful for downsizing the optical fiber fixing section.

[Brief explanation of the drawing]

Fig. 1 is a diagram explaining the first embodiment of the present invention, Fig. 2 is a perspective view showing the structure of the plastic parts in the first embodiment, and Fig. 3 is the structure of the cover used in the first embodiment. A perspective view showing an example; FIGS. 4(a) and (b) are explanatory diagrams for forming an optical fiber insertion hole in a plastic component; FIGS. 5(a), (b) to 8(a); (b) is a diagram explaining the hole formation process; FIG. 9 is a diagram explaining the guiding effect at the end of the hole when inserting the optical fiber; FIG. 10 is a diagram explaining the second embodiment of the present invention. , 11th
Figures (a) and (c) are explanatory diagrams of a conventional optical fiber connection method. 1... Optical fiber core wire 2... Optical fiber 3...
・Connector board 4...Plastic parts 5...
・Optical fiber insertion hole 5'...Axis alignment hole 6...
Opening 7...Cover 8...Pin
9...Heater 10...■Groove
11... Holder plate 12... Sleeve Patent applicant Nippon Telegraph and Telephone Corporation Patent applicant NTT Technology Transfer Corporation. Ward Ward I) 69 school
ku ku t-■

Claims (1)

[Claims] 1. In an optical fiber connector that connects a pair of optical fibers to be connected by abutting and fixing them in a straight hole, the openings at both ends of the hole are formed with the hole, respectively. An optical fiber connector characterized in that an opening is formed at an upper end of an upwardly inclined surface of a member in which the hole is formed, and an opening extending over the entire length of the side wall of the hole is formed in the upper surface of the member in which the hole is formed. 2. Adding a protruding portion of a thermoplastic member with a protruding portion to a pin having a cross-sectional shape equivalent to an optical fiber, or attaching a pin having a cross-sectional shape equivalent to an optical fiber to a protruding portion of a thermoplastic member having a protruding portion. , the pin is embedded in the thermoplastic member by pressing with the flat surface of a heated heater, and then cooled and solidified, and then the pin is pulled out in the longitudinal direction to form a hole for mating the optical fiber. 1. A method for manufacturing an optical fiber connector, characterized in that a member having a hole formed therein is provided on a connector substrate.