JPS6053293B2 - Optical connector manufacturing method and optical connector - Google Patents

Description

Detailed Description of the Invention In the present invention, in an optical connector for interconnecting optical fiber cables used in optical devices, etc. when used as an optical communication transmission medium, the inner surface of the sleeve that fits opposing cores is made of heat-shrinkable tube. The present invention relates to a method of manufacturing an optical connector, which is integrally molded with resin to form an optical connector.

2. Description of the Related Art Conventionally, optical fiber cables have generally been widely used to connect optical circuit elements within each device in an optical communication system. This optical fiber cable is composed of a central core and a cladding on the outer periphery, and a protective plastic jacket, that is, a nylon coat outer skin. In such an optical fiber cable, optical connector members are connected to both ends thereof, and the optical connector members connect various optical circuit elements in the device. Conventionally, this optical connector, including its core and sleeve, has required high precision to prevent an increase in optical coupling loss.
They are constructed by assembling precision-machined metal parts made of stainless steel, etc., and are not mass-producible and are expensive. Therefore, resin molding is required from the viewpoint of mass production or low cost. By the way, when the connector core and sleeve used in the optical connector member are made by resin molding, as shown in FIG. A protective tube 3 made of stainless steel or the like is inserted into the nylon coated outer skin 2. Then, as shown in the figure, the optical fiber and the protective tube are integrated, and a core 4 is formed using a resin mold. On the other hand, the sleeve 5 is formed by resin molding. However, the core 4 and the sleeve 5 have problems such as wear and dimensional accuracy during attachment and detachment as an optical connector, and it has been difficult to produce an optical connector with low optical connection loss. That is, the sleeve 5 is a cylinder for precisely fitting the core 4 to which the optical fiber terminal is fixed and the opposing cores 4' together. Since the sleeve 5 is molded with resin, the dimensional accuracy varies greatly depending on molding shrinkage, molding conditions, etc. Also, core 4
, 4, and the sleeve 5 are made of resin molded material, and therefore dimensional changes occur due to wear and abrasion powder during attachment and detachment, resulting in problems such as optical connection loss as an optical connector. Therefore, an object of the present invention is to solve the above problems, and to provide a method for manufacturing an optical connector made of a removable resin mold.
In order to improve dimensional accuracy and abrasion resistance during attachment/detachment, heat-shrinkable tubes made of fluororesin (TFE, FEP, ETFE) with a low coefficient of wear are inserted into the molding of new optical connector sleeves. It is resin molded and the inner surface of the sleeve is made of fluororesin to create a flexible structure with wear resistance.

Below, as an example of the method for manufacturing an optical connector according to the present invention, a cross-sectional view of the sleeve shown in FIG.
This will be explained using a sectional front view of the sleeve shown in the figure and a sectional view of the connection structure of an optical connector to which the sleeve is applied, as shown in FIG.

As shown in the figure, the resin molded sleeve for optical connectors of the present invention is different from the conventional one shown in FIG. 1 in that it has the same diameter as shown in FIG. , and a heat-shrinkable tube 7 made of fluororesin is inserted into the inner periphery of the sleeve 6 and molded, and the inner surface of the sleeve 6 is formed into a flexible structure with abrasion resistance made of fluororesin as shown in FIG. That's true. That is, a TFE heat shrink tube (manufactured by Pennit KK) 7 is placed in the inner cavity of the core mold (corresponding to the outer diameter of the core) 8 shown in FIG.
After the tube 7 is contracted and fixed by heating at 330° C., the core mold 8 is inserted into the lower mold 9, and the upper mold 10 is fitted into the lower mold 9. Next, a molding material 11 of polycarbonate resin (Mitsubishi Kako CS) is poured from the top of the upper mold 10.
2O3Ol) 12 is injection molded to form the sleeve 6 shown in FIG. The diameter of the core mold 8 is the diameter of the sleeve 6 to shrink and fix the saw heat shrinkable tube to the core mold by heating.
The diameter is slightly larger than that of the cores 4, 4" that are mated within the sleeve 6. Therefore, when the cores 4, 4" are mated within the sleeve 6, heat is applied to prevent the fibers from misaligning. This is because it is necessary to shrink and fix the shrinkable tube 7 to the core mold 8. If molding is performed without shrinking and fixing to the core mold 8, the shrink tube 7 may shift or the resin 12 of the molding material 11 may enter the shrink tube 7, making it impossible to produce a sleeve whose inner surface is made of fluororesin. In an optical connector to which a sleeve formed in this manner is applied, first, as shown in FIG. 2. Also, mold 2' and cladding 1 with epoxy resin to each core 4,
4". Then, when the right core 4 is inserted into the fluororesin 7 on the inner surface of the sleeve 6, the flexible structure of the inner surface 7 or the lubricating effect of the fluororesin ensures a secure fit with high dimensional accuracy. The tube 7 made of fluororesin also has the same properties as general heat-shrinkable tubes: it hardens when heated.However, since fluororesin is originally a very soft material, it has the same property of becoming hard even when heated. There is no change in hardness, and the lubrication effect is great even after heat shrinkage.The sleeve 6
are installed and fixed with the connector housing 13. Furthermore, the left core 4'' is fitted into the sleeve 6 in the same way as the right core, and the connector housing 13'' is attached and fixed, thereby forming an optical connector connection structure. Next, the optical connector can be attached or detached by removing the attached connector housing 13'' and pulling out the core 4'', and then,
It can be attached and detached by fitting it in.
Therefore, in the method for manufacturing an optical connector of the present invention, the inner surface of the sleeve is heated with the TF'E heat shrink tube 7 to further shrink and fix it to form a fluororesin, and then it is injected with polycarbonate resin. By molding to form the sleeve 6, and by molding the optical fibers 2, 2'' with epoxy resin to form the cores 4, 4'', the cores 4, 4.
Since dimensional changes due to wear and variations in optical connection loss can be prevented even if the connector is repeatedly attached and detached using the inside 7 of the sleeve 6, the optical connector can be attached and detached reliably. As described above, according to the method for manufacturing an optical connector according to the present invention, the inner surface of the sleeve is made of fluororesin and molded with resin, thereby preventing wear during attachment and detachment of the core, and improving dimensional accuracy. This method has advantages such as being able to manufacture optical connectors that have good optical connection loss and can be mass-produced.

[Brief explanation of the drawing]

FIG. 1 is a sectional front view of a core coupled to a sleeve of a conventional optical connector member, and FIG. 2 is a sectional front view of molding a sleeve in an embodiment of the optical connector manufacturing method of the present invention.
FIG. 3 is a sectional front view showing the formation of the sleeve, and FIG. 4 is a sectional front view showing the connection configuration of an optical connector to which the sleeve is applied. In the figure, 1... cladding, 2...
Optical fiber sheath, 3...Metal tube, 4,4''.
... Core, 7 ... TFE heat shrink tube,
8...Core mold, 9...Lower mold, 10...
...Upper mold, 11...Molding material, 13,13''
...Indicates the connector housing.

Claims (1)

[Scope of Claims] 1. In a method for manufacturing an optical connector in which a core to which an optical fiber is fixed and a sleeve that fits the opposed cores are molded with resin, a heat-shrinkable material made of a fluororesin is provided in a cavity in a core mold. A step of inserting a tube and shrinking and fixing the heat-shrinkable tube to the core mold by heating, a step of inserting the core mold into a lower mold and fitting an upper mold to the lower mold, and a step of fitting the upper mold to the lower mold. 1. A method of manufacturing an optical connector, comprising the step of injection molding a resin to form a sleeve whose inner surface is made of the fluororesin. 2. An optical connector consisting of a core to which an optical fiber is fixed, a sleeve that fits the opposing cores together, and a connector housing that fixes the sleeve and the opposing cores that are fitted into the sleeve. The optical connector is characterized in that the sleeve is made of a composite resin body having a fluororesin layer on the inner surface into which the opposing cores are fitted.