JP3343379B2 - Preform rod etching equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a surface of a preform rod used for manufacturing an optical fiber.
The present invention relates to a preform rod etching apparatus.

[0002]

2. Description of the Related Art Optical fibers are conventionally manufactured by spinning a preform rod. FIG. 4 (a)
2 shows a perspective view of the preform rod, and FIG. 2B shows a cross-sectional view of the spinning device. As shown in the figure, the preform rod 1 is composed of a quartz base material having a core 2 and a clad 3 serving as a light guide. The preform rod 1 is heated and drawn to a predetermined outer diameter in a spinning furnace 4 composed of an electric furnace or the like, as shown in FIG.

The preform rod 1 for an optical fiber has a V
It is made by a known method such as the AD method. In manufacturing the preform rod 1, variations occur in characteristics of the finished rod, such as cutoff wavelength and dispersion. Therefore, it is necessary to adjust the characteristics of the finished rod. As means therefor, there is an etching treatment for chemically polishing the outer peripheral surface of the preform rod with hydrofluoric acid.

FIG. 5 shows a conventional apparatus for etching the preform rod 1 as described above. FIG. 1 is a perspective view showing an example of a conventional etching apparatus. As shown in the drawing, in the conventional etching apparatus, a tank 5 is filled with an etching solution such as hydrofluoric acid 6, and a number of preform rods 1 to be treated are immersed in the tank 5 and left for a certain period of time.

[0005]

In the conventional etching apparatus as described above, a relatively large amount of hydrofluoric acid 6 is stored in the tank 5 regardless of the number of preform rods to be processed.
Need to be housed inside. Hydrofluoric acid 6, as is well known, is a powerful drug and can pose a danger to workers, and requires particularly careful handling. When hydrofluoric acid 6 is used repeatedly, the etching effect gradually decreases. Therefore, it is necessary to periodically dispose of the waste liquid. However, since the treatment of the waste liquid is not easy, it is desirable that the used amount be as small as possible. Further, the preform rod has a variation in the time to be etched or the like depending on its shape, radius and other various conditions. Therefore, when a large number of preform rods 1 are collectively accommodated in the tank 5 as described above, it is not easy to pull out and take out each of the preform rods 1 at an appropriate timing.
There was also the danger of splashing.

The present invention has been made in view of the above points, and prevents the generation of a large amount of waste liquid for etching, and furthermore, it is easy to manage the etching time etc. individually for each preform rod. It is an object of the present invention to provide a reform rod etching apparatus.

[0007]

A preform rod etching apparatus according to the present invention comprises a plurality of cylindrical containers each containing a preform rod and an etching solution, and a container for moving the cylindrical container together with the preform rod. And a holder for supporting the preform rod and an etching solution stirring member formed on the inner wall surface of the container.

[0008]

This apparatus has a cylindrical container capable of accommodating, for example, one preform rod and having an inner diameter slightly larger than that of the preform rod. A minimum required amount of etching liquid is contained in the cylindrical container, and the cylindrical container is rotated by a container driving unit about a preform rod. The etching solution is stirred by the projections formed on the inner wall surface of the cylindrical container, and the etching effect is enhanced. If a plurality of cylindrical containers each containing a preform rod are rotated using the container driving unit, the etching time of the preform rod can be individually controlled.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is a perspective view showing an embodiment of a preform rod etching apparatus according to the present invention, and a cross-sectional view of one cylindrical container is described on the left side thereof. As shown in the figure, the apparatus of the present invention uses a large number of cylindrical containers 11 for accommodating, for example, one preform rod 10. This cylindrical container 11
The inner diameter of the preform rod 10 is selected to be slightly larger than the outer diameter of the preform rod 10, and a minimum necessary amount of the etching liquid 12 is stored therein. This etching solution 12 is composed of hydrofluoric acid or the like. The inner wall surface of the cylindrical container 11 is provided with a holder member 13 for supporting the preform rod 10 therein and a projection 14 for stirring the etchant.

One holder member 13 is provided at each of the upper and lower portions of the cylindrical container, and the outer surface of the preform rod 10 collides with the inner wall surface of the cylindrical container 11 by grasping the preform rod 10. I try not to. The holder member 13 is formed of, for example, a ring-shaped member partially fixed to the inner wall surface of the cylindrical container 11. In the apparatus of the present invention, the preform rod 10
Is the minimum required amount of the etching solution 12 inside the cylindrical container 11.
Is immersed in. Therefore, it is necessary that the etching liquid 12 sufficiently convects inside the cylindrical container 11 and is further stirred well. For this reason, both ends of the preform rod 10 are previously formed in a tapered shape. Furthermore, the cylindrical container 1
A large number of projections are provided on the inner surface of the preform rod 10 so that when the cylindrical container 11 rotates, the etching solution 12 is sufficiently stirred and the new etching solution 12 always contacts the surface of the preform rod 10. On the other hand, the cylindrical container 11 as described above
Are fixed on the rotating plate 16 of the container drive unit 15, respectively, and in this case, are configured to be rotated around the preform rod 10.

FIG. 2 is a diagram showing a specific embodiment of the apparatus of the present invention. (A) is an internal configuration diagram of a container driving unit, and (b) is a cross-sectional view showing an etching liquid replacement structure. In the figure, as shown in (a), a large-diameter spur gear 17A and a large-diameter spur gear, each of which is coaxially connected to a rotating plate 16 that supports the cylindrical container 11 shown in FIG. A small-diameter spur gear 17B connecting between 17A is provided. As shown, each spur gear 17A, 17B
Are connected to each other, and the drive shaft 1 of the motor 18 is
9 rotates one large-diameter spur gear 17A, and the rotation is transmitted to all spur gears 17A, 1A.
7B is configured to rotate. Thereby, as shown in FIG. 1, all the rotating plates 16 of the container driving unit 15 rotate in the direction of the arrow.

As shown in FIG. 2B, the cylindrical container 11 shown in FIG. 1 can be provided with an inlet 11A and an outlet 11B at its lid and bottom, respectively. When the etching liquid 12 such as is replaced, a configuration may be adopted in which the replacement can be automatically performed using a pump or the like. This is a configuration that is highly effective for preventing the danger of the operator coming into contact with the etching solution and improving the safety of the operation.

FIG. 3 shows a reaction formula in the case where the above-described etching process is performed. That is, as shown in the figure, the preform rod is made of quartz, and when its surface is treated with hydrofluoric acid, a waste liquid containing water is generated. If the mass of the portion to be treated on the preform rod surface is determined in advance, the necessary minimum amount of the etching solution 12 can be calculated using this reaction formula. Therefore, the etching liquid 12 may be replaced every time one preform rod is processed, or the etching liquid 12 may be replaced after processing a plurality of preform rods by calculation.

The preform rod etching apparatus according to the present invention having the above-described structure is provided for each of the preform rods 10.
Are individually housed in the cylindrical container 11 and immersed in the minimum necessary amount of etching solution, and simultaneously rotating these cylindrical containers 11 using the container driving unit 15, the etching amount is sufficiently smaller than in the conventional case. The etching process can be performed using the liquid. Therefore, the actual amount of waste liquid can be greatly reduced as compared with the conventional case.

Furthermore, since the container is different for each preform rod as described above, the processing time can be freely selected for each preform rod, and the etching process for each preform rod can be safely and individually stopped. It is. In this case, the cylindrical container 11 may be detached from the container driving unit 15, or the internal etching solution may be discharged or a cleaning solution may be injected by a mechanism as shown in FIG. The etching process may be automatically stopped as described above. This has the effect that the cutoff wavelength and dispersion characteristics of each preform rod can be freely selected.

The present invention is not limited to the above embodiment. In the above-described embodiment, the example in which the preform rods are accommodated in the cylindrical container one by one has been described. Further, the cross-sectional shape of the cylindrical container is not necessarily cylindrical, and may be, for example, a polygonal structure. The stirring member for stirring the etching solution can be variously deformed, such as a projection, a groove, a fin, and a stirring rod, according to the internal structure of the container. Further, the container may be configured to perform not only a rotational motion but also a motion such as a vibration, a swing, and an inversion.

[0017]

According to the preform rod etching apparatus of the present invention described above, a preform rod and a minimum necessary etching solution are stored in a cylindrical container, and a plurality of such cylindrical containers are operated by a container driving unit. Because of the movement, the preform rod can be etched using a much smaller amount of etchant than in the prior art. In addition, since the preform rod is supported inside the cylindrical container by using a holder member and the etching solution is stirred by using a stirring projection or the like, the preform rod can be efficiently etched with a small amount of etching solution.

[Brief description of the drawings]

FIG. 1 is a perspective view and a main part longitudinal sectional view showing an embodiment of a preform rod etching apparatus of the present invention.

FIGS. 2A and 2B show a specific configuration of the apparatus of the present invention, wherein FIG. 2A is a specific plan view of a container driving unit, and FIG.

FIG. 3 is an explanatory diagram showing a reaction formula of an etching solution and its contents.

4A and 4B show a manufacturing process of an optical fiber, wherein FIG. 4A is a perspective view of a preform rod, and FIG. 4B is a cross-sectional view of a spinning device.

FIG. 5 is a perspective view of a conventional preform rod etching apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Preform rod 11 Cylindrical container 12 Etching liquid 13 Holder member 14 Projection (etching liquid stirring member) 15 Container drive part 16 Rotating dish

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C03B 37/014 C03B 20/00 B08B 3/00-3/14

Claims (1)

(57) [Claims] 1. A plurality of cylindrical containers each containing a preform rod and an etching solution, and a container drive unit for moving the cylindrical container together with the preform rod, wherein the inside of the cylindrical container is An apparatus for etching a preform rod, comprising: a holder member for supporting the preform rod; and an etchant stirring member formed on an inner wall surface of the container.