JPH01192739A - Apparatus for drawing optical fiber - Google Patents

Abstract

PURPOSE:To enable drawing and coating of an optical fiber at a high speed without reducing tensile strength, by passing a spun optical fiber through coating dies, coating the optical fiber and providing optical fiber position sensors near the coating dies. CONSTITUTION:A fiber position sensor (14a) is provided near a primary coating die (5a) between the primary coating die (5a) and an outside diameter measuring instrument 3 for the fiber and a fiber position sensor (14b) is also provided just on a secondary coating die (5b). Drawing operation is initially carried out by sensing the position of a fiber 4 by drawing in a state of no coating with the fiber position sensors (14a) and (14b). The fiber is then passed through coating dies (5a) and (5b) to sense the fiber position. If the fiber position is deviated from the position without passing the fiber through the coating dies, die holders (6a) and (6b) are moved to eliminate the deviation of the fiber position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber drawing apparatus, and more particularly to reducing breakage during high-speed drawing.

[Conventional technology and its issues]

A conventional optical fiber drawing device has a structure as shown in Fig. 2, which includes a drawing heating furnace (2), a fiber outer diameter measuring device (3), a primary coating die (5a), Dice holder (6a), UV lamp for curing primary coating material (7a)
), secondary coating die (5b), die holder (6b
), a UV lamp (7b) for curing the secondary coating material, an outer diameter measuring device for coated fiber (8), a capstan (9), a pulley 00, and a winder.

For fiber spinning, the preform (1) is heated in a heating furnace (2).
The fiber (4) drawn out from the free end of the preform (1) is wound up at a constant speed by the winder 00 through the capstan (9) and pulley 00. be exposed. To coat the fiber, when it reaches a predetermined diameter, pass the fiber through the -th layer die (5a), harden the coating material with a UV lamp (7a), and then pass it through the second layer die (5b). This is done by curing the coating material with a UV lamp (7b). Depending on the type of resin that is the coating material, the resin may be cured with a heating furnace instead of the UV lamp.

When passing the dice fiber, use the dice holder (6
A dice holder is installed so that the fiber (4) is located at the center of the fibers (a, 6b), the dice (5a, 5b) are placed on the dice holder, and the fiber is passed through.

In addition, if the die can be divided, only one half is attached to a die holder, and the die holder is moved so that the fiber is located at the center of the die, so that the core of the die and the position where the fiber passes are aligned. However, in the prior art, due to the gap created between the die holder and the die, the position where the fiber passes before the die is attached does not match the position where the fiber passes after the die is attached, and the fiber is bent. Therefore, during high-speed drawing, the fiber comes into contact with the die and is likely to break, and during low-speed drawing, the coated fiber cross section tends to be eccentric. Particularly, in the case of simultaneous multilayer coating such as a double-layered die, contact between the die and the fiber is more likely to occur, and the strength of the coated fiber is significantly reduced.

The present invention has been made in view of the above points.
The objective is to provide an apparatus for drawing and coating optical fibers at high speed without reducing tensile strength.

[Means to solve the problem]

In order to achieve the above object, according to the present invention, an optical fiber preform is softened in a heating furnace and an optical fiber is spun,
There is provided an optical fiber drawing apparatus for passing the optical fiber through a coating die, applying a coating, and winding the optical fiber, characterized in that an optical fiber position detector is provided in the vicinity of the coating die.

In an optical fiber drawing apparatus having such a configuration, since an optical fiber position detector is provided near the coating die, the position of the optical fiber can be confirmed before and after passing the optical fiber through the coating die. Furthermore, by moving the coating die and setting it at a position determined by the optical fiber position detector, the position of the optical fiber after passing through the coating die can be made to match the position before passing through the coating die. . Therefore, it is possible to avoid contact of the optical fiber with the coating die during coating.

〔Example〕

The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 is an explanatory diagram of an embodiment of an optical fiber drawing apparatus according to the present invention, and compared with FIG. ), the fiber position detector (14) is placed close to the die (5a).
a), and a fiber position detector (14b) was also installed directly above the secondary coating die (5b). In the drawing process, first, the position of the uncoated fiber is detected by the fiber position detector (14a, 14b). Next, the fiber is passed through the coating die (5a, 5b).
The fiber position is detected by passing through the coating die, and if the fiber position deviates from the position when the coating die is not passed through, the die holder (6a, 6b) is moved to eliminate the fiber position deviation. As a fiber position detector, an outer diameter measuring device with this function may be used, but in order to detect the fiber position directly above the coating die, it is desirable to install a dedicated detector. A non-contact detector using scanning laser light can detect orthogonal two-wheel directions on the order of μ.

When wire is drawn using the above-mentioned device, in the case of an open-type coated die, the wire drawing speed is 3 times that of the conventional method.
Even when the speed was increased to about 00 m/sin, no problem of wire breakage or strength reduction occurred.

In addition, in the case of pressurized coating dies, conventionally
A decrease in strength was observed even at a low speed of 70 m/sin, but no problem occurred with this device even at a speed of 400 to 600 m/sin. In this embodiment, the fiber position detector is installed directly above the dice, but it may be installed directly below the dice.

〔Effect of the invention〕

As explained above, according to the present invention, since the optical fiber position detector is installed near the coating die, the optical fiber is drawn without contacting the coating die, and the drawing speed can be increased. It has a positive effect.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a conventional example. l... Preform, 2... Heating furnace, 3...
Fiber outer diameter measuring device, 4... fiber, 5a,
5b...Dice, 6a, 6b...Dice holder, 7a, 7b...UV lamp, 8...Outer diameter measuring device for coated fiber, 9...Capstan, 1
0... Pulley, 11... Winding Kei, 12...
1-layer coated fiber, 13...2-layer coated fiber,
14a, 14b...Fiber position detector.

Claims (1)

[Claims] In an optical fiber drawing device that softens an optical fiber preform in a heating furnace to spin an optical fiber, passes the optical fiber through a coating die to apply a coating, and winds the optical fiber, an optical fiber position detector is installed near the coating die. An optical fiber drawing device characterized in that: