JPH0368905A - Method and device for coating fusion spliced part of optical fiber - Google Patents

Abstract

PURPOSE:To execute good coating by injecting a UV curing resin into a mold from the position deviated in an axial direction from the part to be coated and stopping the injection after injecting and packing this resin into the in-mold cavity for the purpose of forming the coating again and then irradiating only the recoating part with UV rays. CONSTITUTION:The juncture 8 of fibers (f) is aligned to the center of the molds and is fitted into grooves (g); thereafter, both the upper and lower molds are mated. The UV resin is then pressurized and is injected from a UV resin injection hole 4 into the grooves and is run in the direction of the axial line in the slight spacing (k) between the inside surface of the hole formed by the two grooves and the outside surface of the fibers (f) so that the UV resin is packed into the annular cavity on the outer periphery of the fibers 10 of the optical fibers. After the resin is fully packed into this cavity, the injection is stopped and the resin is irradiated with UV rays 18 through the block 1. Since only the recoating part 3 is irradiated with the UV rays 18, only this part is cured and shrunk and the UV resin in the slight spacing (k) between the front end of the existing coating C and the inside surface of the hole of the molds does not cure. The recoating part 3 cures and the outside diameter is the same in size and quality as the existing coating C. The smooth outside surface of the coating is thus formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] After removing the coating from the connecting end of an optical fiber and fusion splicing the exposed optical fiber tip, the optical fiber connecting end is installed in a coating mold. Then, the mold is filled with ultraviolet curable resin (hereinafter referred to as rUV resin), and ultraviolet rays are irradiated to cure the UV f inside the mold.
By curing the fM resin, the contact end of the optical fiber is exposed to UVI.
Regarding the coating method and coating device for recoating with oil, to avoid the occurrence of deburrs on the recoating outer peripheral surface that must be removed after removal from the mold, and to omit deburr removal work in the recoating process. It is effective when used.

[Prior art and issues] Attach the spliced optical fiber joint to the mold.

The technique of press-fitting UV4i1 resin into the cavity of a mold and curing it by irradiating the UV resin in the cavity with ultraviolet rays is conventionally known. An example of this is shown in Japanese Patent Laid-Open No. 61-277907. The outline of this technology (hereinafter referred to as "prior art") is as shown in FIGS. 3 and 4, and a cylindrical through hole is formed by a pair of left and right molds 11, ]2 and a transparent plate 13. , the optical fiber connection portion is attached to this through hole. Since the outer diameter of the coating of the optical fiber is the same as that of the cylindrical through-hole, and the coating is removed from the connection end of the optical fiber, an annular cavity is formed between the core alO of the optical fiber and the inner surface of the circular through-hole. 14 is formed.

A resin reservoir 15 is provided on the mating surface of the mold 12, and a large number of shallow V grooves 16 are provided to communicate the resin reservoir and the cavity 14.
6 After attaching the optical fiber to the mold, insert the resin reservoir 1 through the through hole 17.
5, resin is injected into the cavity 14 through the resin reservoir 15 and 16 to fill the cavity, and then the resin in the cavity is irradiated with ultraviolet rays 18 to be cured. In this case, the resin is continuously press-fitted until the resin hardens.

This prevents the outer diameter ↑L of the re-coated portion (coating of the connection portion) from becoming smaller than the outer diameter of the existing wave crest due to shrinkage during curing. In addition, the resin in the shallow VfM16 is also cured by UV irradiation, so when the optical fiber is removed from the mold, the fine hair-like resin that has hardened in this tllt +,6 becomes a paris on the outer surface of the recoated part of the optical fiber. remain. Since the outer surface of the optical fiber coating must be a smooth cylindrical surface, this paris must be removed after removal from the mold. This process of removing paris is tedious because the traces left after removing the paris must be smooth, and the traces that are removed may be uneven. Unreasonable bending force may be applied to 10, which may increase optical transmission loss at the connection end.

The present invention provides a t
The objective is to press fit the JV resin into the empty space 7fi14.

[Means taken to solve the problem] The measures taken to solve the above problem are comprised of the following elements.

(a) A cylindrical through hole is formed using a pair of upper and lower molds, and the inner diameter of this cylindrical through hole is set to be U larger than the outer diameter of the optical fiber coating.
(b) The center of the pair of upper and lower molds should be transparent, and both sides should be opaque.

(c) Make +lJ of the transparent part approximately equal to the length of the recoated part of the optical fiber; (d) Provide one resin injection hole in the opaque part of either the upper or lower mold.

[Operation] Align the upper and lower molds and attach the optical fiber connection end to the cylindrical through hole. At this time, the portion of the optical fiber from which the coating has been removed is aligned with the transparent portion of the mold.

Press the UV resin through the resin injection hole provided in the opaque part,
Inject it into the cavity inside the mold by flowing it in the axial direction of the mold,
After sufficient injection, stop pressurization.

After the injection is completed, ultraviolet rays are irradiated through the transparent part at the center of the frame to only the re-coated part to harden only the re-coated part.

When the recoating section cures, it shrinks to the same diameter as the existing coating.

When the optical fiber is removed from the mold, only the recoated portion is cured by irradiation with ultraviolet rays, and the resin interposed between the existing outer surface of the IXI target and the inner surface of the hole in the mold is not cured. Therefore, no debris remains at both ends of the recoated portion.

Therefore, there is no need to perform deburring work on the re-capped part after removing it from the mold.

[Implementation example] One embodiment will be described with reference to FIGS. 1 and 2.

Opaque square blocks 2, 2 are glued and fixed on both sides of a transparent square block 1 to form upper and lower molds B, , B, and the mating surface S with each mold B, , B is formed. , a groove g with a semicircular cross section in S
is formed. The diameter d□ of this 'rRg is slightly larger than the diameter d2 of the covered ylC of the optical fiber f. This difference in diameter corresponds to the amount of shrinkage during curing of the UV resin in the recoating section 3 of the optical fiber f. Also, the inside bl of the central transparent block 1 is approximately equal to the width of the recoated portion of the optical fiber.

A resin injection hole 4 is provided in the opaque block 2 of one of the upper and lower molds, and this is communicated with mg.

The ears 5 and 6 of both types B1 and B are connected by a hinge pin 7.

Align the connecting part 8 of the optical fiber f with the center of the mold, and insert it into the groove g.
Fit the top and bottom molds together. after that.

UV resin is pressurized and injected into mg from the UV resin injection hole 4, and is caused to flow in the axial direction through the minute gap k between the inner surface of the hole formed by one image and the outer surface of the optical fiber f. An annular cavity around the outer periphery of the core wire 10 is filled with UV resin. After this cavity is completely filled with resin, the press-fitting of the resin is stopped and the ultraviolet rays are passed through the transparent block 1 of the mold.
8. Since this ultraviolet ray 18 is irradiated only to the recoating part 3, only this part hardens and shrinks, and the UV rays in the minute gap between the tip of the existing coating C and the inner surface of the hole in the mold
The resin does not harden.

When the recoating section 3 is cured and the optical fiber f is taken out from the mold, the recoating section 3 is cured and its outer diameter is the same as that of the existing coating C.
It is of the same type and quality as , and has a smooth outer covering surface.

In addition, a semicircular protrusion 9 is provided on the inner surface of the end of the mold groove g on which the injection hole 4 is provided to prevent the UV resin injected into the mold hole from flowing out from this end. to ensure flow into the cavity for forming the recoating 3.

[Effects] The problem of the present invention is novel. Therefore, the unique effect of the present invention is that the above-mentioned problems of the present invention are solved, and thereby the above-mentioned problems of the prior art are eliminated.

Note that the molds in one or more of the above descriptions are not limited to molds that are matched vertically, but also include molds that are matched horizontally. Furthermore, the mold is not limited to just a two-piece mold.

It is also possible to adopt a three-part or four-part mold.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, and FIG. 2 is a perspective view of an embodiment of the present invention. FIG. 2 is a cross-sectional view of the mold shown in FIG. 1 with an optical fiber attached thereto. FIG. 3 is a sectional view of the prior art, and FIG. 4 is an enlarged perspective view of a portion of FIG. 3. In the figure, 1... Transparent block, 2... Opaque block, 3... Optical fiber recoating part, 4... Resin injection hole, 5.6... Ear, 7... Hinge, 8... Optical fiber connection portion, 9... Protrusion. 10... Optical fiber core wire, 11.12... Type, 1
3...Transparent plate, 14...Cavity, 15...Resin reservoir, 16...V groove, 17...Through hole, 18...Ultraviolet light, B1...Upper mold, B, ...lower mold, S...upper mold B
1. The mating surface with lower mold B2. g...I book of semicircular cross section, d,...ffl Diameter of g, d2...Diameter of optical fiber coating, f...Optical fiber, C...Optical fiber coating, b . . . . Width of transparent block 1, B 2 . . . Width of the recoated portion of the optical fiber, k . . . Minute gap. Figure 1

Claims (2)

[Claims] (1) After removing the coating from the optical fiber connection end and fusion splicing the exposed optical fiber tip, place the optical fiber connection end into a coating mold, and fill the mold with ultraviolet curing resin. However, in a coating method in which the UV-curable resin in the mold is cured by irradiation with ultraviolet rays, and the optical fiber connection part is re-coated with the UV-curable resin, a position shifted in the axial direction from the part to be coated with the UV-curable resin is used. After filling the cavity in the mold with UV-curable resin to form the re-coating, the injection of UV-curable resin is stopped, and then only the re-coating part of the optical fiber is filled in the radial direction of the optical fiber. irradiate ultraviolet rays from
A method for re-coating the above-mentioned optical fiber. (2) A cylindrical through hole is formed in a pair of upper and lower (or left and right, same hereinafter) molds, and the inner diameter of this through hole is made larger than the outer diameter of the optical fiber coating by the shrinkage during curing of the UV resin, The center of the pair of upper and lower molds is made transparent, the both sides thereof are made opaque, the width of the transparent part is made approximately equal to the length of the recoated part of the optical fiber, and one resin is placed in the opaque part of either of the pair of upper and lower molds. A coating device for optical fiber fusion splices with injection holes.