JPS6328195Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Technical field of the invention This invention relates to an improvement of a coating jig used for applying a resin coating to the surface of an optical fiber.

(b) Background of the technology When manufacturing optical fibers, a high-purity glass base material is produced in advance by vapor phase chemical reaction (CVD method), and the base material is heated and stretched to obtain the desired outer diameter. It is common to spin the fibers into optical fibers. However, the as-spun optical fiber is weak in strength.
Moreover, it is difficult to maintain a low transmission loss due to the adhesion of dust or easy scratches on the outer surface.

Therefore, in order to protect the surface of such an optical fiber, immediately after spinning, the surface is coated with a resin called a primary coating using silicone resin or the like.

(c) Prior art and problems A coating jig for coating silicone resin consists of a container containing liquid resin and a taper nozzle attached to the bottom of the container. It is made by machining as shown in Figure 2a. However, in the conventional taper nozzle 7 shown in FIG. 2a, as the amount of optical fiber passing increases, the diameter of the tip microhole 72 of the inner taper part 71 of the taper nozzle wears out due to contact friction with the optical fiber. As a result, changes in the thickness of the coating layer occur, causing deterioration of loss strength characteristics, and improvement thereof is desired. In addition, in order to prevent changes in the hole diameter due to wear, a hole 7 of a predetermined length and a uniform diameter is provided at the tip of the internal tapered portion 71, as shown in FIG. 2b.
A taper nozzle having a structure in which a hole 73 is formed is also considered, but due to the nature of metal cutting, a horizontal discontinuous step occurs at the connection between the inner surface taper part 71 and the predetermined length uniform diameter hole 73, and when inserting the optical fiber, This optical fiber had the disadvantage that it collided with steps, making it very difficult to perform the work.

(d) Purpose of the invention The purpose of this invention is to provide a new optical fiber coating jig that eliminates the unevenness of the resin coating thickness on the optical fiber surface and improves workability. .

(e) Structure of the invention Briefly stated, this invention changes the material of the taper nozzle attached to the center of the bottom of the resin container of the jig for optical fiber coating to ceramic, and creates a uniform diameter hole with no step continuous to the taper part. It is characterized by a nozzle structure that realizes this, making it easy to insert the optical fiber into the tapered nozzle, and making it possible to prevent non-uniformity in the resin coating thickness.

(f) Embodiment of the invention Figure 1 is a sectional view of essential parts showing an embodiment of an optical fiber coating jig to which this invention is applied.
A set screw 5 is attached to the bottom of the taper container 2 so that the ceramic taper nozzle 3 is fitted into the central concave part of the bottom of the aluminum taper container 2 and pressed by the pressing plate 4.
It is screwed on by. A predetermined amount of silicone resin 6 is injected into the tapered container 2 of the coating jig constructed as described above, and the optical fiber 1 is immersed in the silicone resin from above the coating jig, so that the tip of the tapered nozzle 3 is uniformly heated. It passes through the diameter hole and is coated with resin.

FIG. 3 is an enlarged sectional view of the taper nozzle 3, which is made of ceramic and has an internal tapered portion 31 and a uniform diameter hole portion 32 of a predetermined length formed continuously at the end thereof. By using a ceramic material, a taper nozzle having an internal tapered part 31 with a predetermined length left at the center of the bottom is first formed by a press sintering method, and then a hole 32 of uniform diameter is penetrated by cutting. A taper nozzle with no steps is manufactured. The ceramic taper nozzle manufactured by the above manufacturing method is durable and has good processing accuracy. In particular, the eccentricity and verticality of the uniform diameter hole are excellent, and it is possible to eliminate the drawbacks of the conventional nozzle mentioned above.

(g) Effects of the invention As explained above, by applying the optical fiber coating jig of the invention, it becomes easier to insert the optical fiber into the tapered nozzle, and it is expected that workability will be improved, and the coating thickness can be reduced. This makes it possible to easily produce optical fibers with uniform and high performance, and is extremely advantageous when applied to the production of long optical fibers.

[Brief explanation of drawings]

Figure 1 is a sectional view of essential parts showing an embodiment of an optical fiber coating jig to which this invention is applied, Figures 2a and b are enlarged sectional views of a conventional taper nozzle, and Figure 3 is an enlarged sectional view of a conventional taper nozzle.
The figure is an enlarged cross-sectional view of a main part showing an embodiment of the taper nozzle according to this invention. 1 is an optical fiber, 2 is a tapered container, 3 is a tapered nozzle, 4 is a holding plate, 5 is a set screw, 6 is a silicone resin, and 7 is a tapered nozzle.

Claims (1)

[Scope of utility model registration request] In a coating jig used for inserting an optical fiber into a liquid resin stored inside and applying a resin coating to its surface, the coating jig is concentric with the upper tapered container 2 and the lower end of the tapered container. and a tapered nozzle 3 mounted on the tapered container, and the tapered nozzle is made of a ceramic member having a tapered hole continuous to the internal tapered surface of the tapered container and a uniform diameter hole continuous to the end thereof. An optical fiber coating jig featuring: