JPH0313178B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of coating a glass fiber for optical transmission (hereinafter referred to as an optical fiber) with a resin and an apparatus therefor.

Optical fiber is being put into practical use as a new transmission method due to its excellent transmission characteristics such as high capacity and low loss, as well as the advantages of non-induction and light weight. Optical fiber is made of glass and is processed to a diameter of 200 μm or less, so its mechanical strength is one of its most important properties. In order to improve this mechanical strength, a so-called tandem primary coat is applied and cured immediately after the optical fiber base material is molten and drawn to maintain the virgin strength of the glass and prevent subsequent scratches. (Japanese Unexamined Patent Publication No. 51-100734).

Conventionally, the die-depping method, the felt method, the spray method, etc. have been used as this coating method, but each method has its advantages and disadvantages. is superior and is the most commonly used. However, the die depping method is 2
It is impossible to form a coating film with a thickness of ~3 μm or less, and the spray method has the disadvantage that it is difficult to coat the optical fiber without causing vibrations.

The present invention provides a method and apparatus capable of coating an optical fiber without applying vibration in a spray method, and the present invention provides a method and apparatus that can coat an optical fiber without applying vibrations. A method of coating a glass fiber for optical transmission, which comprises spraying the fiber toward the fiber after being drawn through the center of the fiber, and a plurality of hopper-like containers of different sizes for carrying out the above method, each The containers are stacked with gaps between them to form a plurality of passages, and the passages form concentric openings each having at least one carrier gas opening and at least one resin composition opening at the end of the container. The present invention relates to a coating apparatus for the above-mentioned method of coating a glass fiber for light transmission, in which the glass fiber for light transmission is passed through the center of the concentric opening.

A method of coating optical glass using the apparatus of the present invention will be explained with reference to FIG.

The optical fiber 3 obtained by melting and drawing the optical fiber base material 1 in the drawing furnace 2 is coated with a resin in the coating device 4 of the present invention and hardened in the baking furnace 5 before coming into contact with other solid materials. It is then wound up by a winding machine 6. 7 is a resin composition recovery device.

FIG. 2 schematically shows an example of the coating apparatus of the present invention. FIG. 2A is an overall view, and FIG. 2B is a longitudinal sectional view. As can be seen from the figure, the device 4 has hopper-shaped containers 11, 12, 13, and 14 of different sizes stacked on top of each other with gaps between each container to form a plurality of passages a, b, and c. The passageway defines a plurality of openings a', b', c' at the ends of the container. Carrier gas (air, nitrogen, etc.) at the same pressure in passages a and c, b
The resin composition is supplied to the The carrier gas is a′,
When spraying from the ring-shaped opening c', the resin composition from the ring-shaped opening b' is atomized, and the optical fiber is coated with this atomized resin composition.

The ring-shaped openings a', b', and c' may be on the same transverse plane, but the ring-shaped openings a', b', and c' may be in the same transverse plane, but the ones that form a conical shape as they move toward the inside, as shown in Figure 2B, It can be said that it is preferable from the point of view of uniformity, etc.

In the coating method using the apparatus of the present invention, since the drawn optical fiber is passed through the center of the ring, uniform pressure is applied from the circumferential direction, and no vibration is applied to the optical fiber. Furthermore, it is possible to apply the resin composition to the circumferential surface of the optical fiber in a uniform thickness.

The resin composition used in the present invention is not particularly limited, but it is preferably one that can be cured by reaction with heat, ultraviolet rays, electron beams, etc., and preferably has a viscosity of 500 cps or less to enable spraying. It is also possible to keep the entire application device or atomizer at 60-80°C to reduce the apparent viscosity of the resin.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the overall flow when coating optical glass using the apparatus of the present invention, Fig. 2 is a schematic diagram of the apparatus of the present invention, and Fig. 2A is an overall view;
Figure B is a longitudinal sectional view.

Claims (1)

[Claims] 1. A carrier gas and a resin composition are sprayed from each opening of a sprayer having a plurality of concentric openings toward a drawn optical transmission glass fiber passing through the center of the opening. A method of coating glass fiber for optical transmission, comprising: 2 A plurality of hopper-shaped containers of different sizes are stacked with gaps between each container to form a plurality of passages, and the passages have an opening for the carrier gas and an opening for the resin composition at the end of the container. at least 1 each
A device for coating a glass fiber for optical transmission, which is formed by forming a concentric opening having the above configuration, and passing a glass fiber for optical transmission through the center of the concentric opening.