JPH09208249A - Method for drawing optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avert the damage of the coating layer of a coated fiber by the optical fiber splinters pricked to a pressing belt and prevent the slip of the coated optical fiber at a take-off capstan. SOLUTION: This method for drawing the optical fiber 3 comprises heating and drawing an optical fiber preform 1 to obtain the optical fiber 3, applying coating layers 6, 6' on the outer side of the optical fiber 3 to obtain the coated optical fiber 7, taking off the coated optical fiber 7 by the take-off capstan 12 and taking up the optical fiber by a taking-up means 16. The passage route for the coated optical fiber 7 between the take-off capstan 12 and the taking-up means 16 is provided with a winding angle changing means (a guide roller 14 in this embodiment) so that the taking-up of the coated optical fiber 7 is executed in the state of parting the pressing belt 13 from the take-off capstan and adjusting the taking-up angle of the coated optical fiber 7 at the take-off capstan 12 by the winding angle changing means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber drawing method.

[0002]

2. Description of the Related Art FIG. 5 shows an example of an optical fiber drawing device. However, here, an example of an optical fiber drawing device for producing a coated optical fiber having two coating layers is shown.
As shown in FIG. 5, in this optical fiber drawing device,
Reference numeral 2 is a drawing furnace for heating and melting the optical fiber preform 1 and drawing it to form the optical fiber 3, and reference numeral 4 is an outer diameter measurement for measuring the outer diameter of the obtained optical fiber 3. Reference numeral 5 is an optical fiber cooler for cooling the optical fiber 3 by directly blowing a cooling gas onto the optical fiber 3.

Reference numeral 8 is a coating layer forming means for forming a coating optical fiber 7 by applying a coating layer 6 (6 ') to the outside of the optical fiber 3. The coating layer forming means 8 is, for example, of the optical fiber 3. A resin coating die 9 for coating a resin such as an ultraviolet curable resin on the outside, and a resin curing device 10 such as an ultraviolet irradiation source for irradiating the ultraviolet curable resin with ultraviolet rays to cure the resin.

However, here, in order to form two layers of the coating layers 6 (6 '), the coating layer forming means 8 is provided in two stages in series, and in order to surely cure the coating layers 6, 6'. Further, a resin curing device 10 'is further provided below it.

Reference numerals 12 and 13 respectively denote a take-up capstan and a pressing belt for pressing the optical fiber 3 not having the coating layers 6 and 6'or the coated optical fiber 7 on the take-up capstan. A pair of pulling means 11 for pulling the coated optical fiber 7 is formed.

In this take-up means 11, the holding belt 13 is taken up by the air cylinder drive and the capstan 1 is taken.
The optical fiber 3 and the coated optical fiber 7 are pulled up by being sandwiched between the capstan 12 and the pressing belt 13 and pulled up.

Then, the take-up speed of the optical fiber 3, that is, the rotation speed of the take-up capstan 12 is set so that the measured value of the outer diameter of the optical fiber 3 obtained by the above-mentioned outer diameter measuring device 4 becomes a predetermined constant value. Adjusted.

Reference numeral 14 'is a rotatably fixed guide roller for guiding the coated optical fiber 7 to a desired passage path. Reference numeral 15 is a dancer that adjusts the slack of the coated optical fiber 7 caused by changes in the take-up speed of the take-up means 11 and the take-up speed of the take-up means 16 described later, and the reference numeral 16 is finally the coated optical fiber 7. Is a winding means for winding up.

Usually, the winding speed of the winding means 16 is appropriately changed so that the length of the slack of the coated optical fiber 7 wound around the dancer 15 falls within a predetermined range.

A conventional method for drawing the optical fiber 3 to obtain the coated optical fiber 7 with this optical fiber drawing apparatus will be described below.
As shown in FIG. 5, first, the optical fiber preform 1 is heated and melted by the drawing furnace 2 and drawn into the optical fiber 3, which is then cooled by the optical fiber cooler 5 provided below the drawing furnace 2. Cooling.

Then, with the resin coating die 9 removed from the passage of the optical fiber 3, the optical fiber 3 is passed through the resin curing device 10 which is not irradiated with ultraviolet rays, and is sandwiched between the take-up capstan 12 and the pressing belt 13. Then, the take-up capstan 12 is driven to take the optical fiber 3. The above process is called an optical fiber pulling process.

While the optical fiber 3 is being taken up by the capstan 12 in this manner, the optical fiber 3 is taken out.
The outer diameter of the resin is stabilized to a desired value, and then the resin-coated die 9 is attached to the passage of the optical fiber 3 for wire passing, and an uncured ultraviolet curable resin is supplied to the resin-coated die 9 and the resin is cured. Ultraviolet irradiation is started from the container 10, the coating layers 6 and 6'are applied to the outside of the optical fiber 3 to obtain the coated optical fiber 7, and the take-up means 11, the guide roller 14 ',
And winding by the winding means 16 via the dancer 15.

In the above-mentioned conventional method for drawing the optical fiber 3, the winding means 16 has a large winding diameter while the coated optical fiber 7 is being wound. Since the winding length of No. 1 cannot be measured, this was measured by the number of rotations of the take-up capstan 12.

Further, while the contact surface of the take-up capstan 12 with the optical fiber 3 is made of metal, ceramic or the like and has a high mechanical strength and a small friction with the optical fiber 3, the belt portion of the pressing belt 13 has a small portion. It is made of rubber or the like, which has a slightly low mechanical strength but has a large frictional force with the optical fiber 3. Normally, the pressing pressure by the pressing belt 13 is set to be slightly stronger than the optimum value for the coated optical fiber 7 so that the optical fiber 3 does not slip on the take-up capstan 12.

[0015]

As a result of setting the holding pressure of the holding belt 13 to be strong as described above, the optical fiber 3 sometimes cannot withstand the holding pressure, so that the space between the take-up capstan 12 and the holding belt 13 is reduced. There was a case where it was broken and the shards stuck into the belt portion of the pressing belt 13. As a result, when the coated optical fiber 7 is taken out at this portion next, the coating layer 6 on the surface of the coated optical fiber 7
However, there is a problem that is damaged by the fragments of the optical fiber stuck on the pressing belt 13.

In order to avoid this problem, if the coated optical fiber 7 is to be taken only by the take-up capstan 12 without using the holding belt 13, the take-up capstan 1
Since the frictional force between 2 and the coated optical fiber 7 was insufficient, the coated optical fiber 7 slipped on the take-up capstan 12. As a result, the take-up efficiency of the coated optical fiber 7 is deteriorated, and a measurement error in measuring the winding length of the coated optical fiber 7 by the take-up capstan 12 is increased, or the take-up capstan 12 is used.
There is a problem that the outer diameter of the optical fiber 3 fluctuates because the take-up tension of the coated optical fiber 7 fluctuates.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to prevent the coating layer of the coated optical fiber from being damaged by the fragments of the optical fiber piercing the pressing belt, and to take up the capstan. It is an object of the present invention to provide an optical fiber drawing method capable of obtaining a high-quality coated optical fiber by preventing slippage of the coated optical fiber in the above.

[0018]

According to a first aspect of the present invention, there is provided a method for drawing an optical fiber, wherein an optical fiber preform is heated and drawn to obtain an optical fiber, and the optical fiber is taken out to capture a capstan and a pressing belt. After the optical fiber pulling step of pulling the optical fiber in a state of being sandwiched by the optical fiber, a coating layer is applied to the outside of the optical fiber to obtain a coated optical fiber, the coated optical fiber is pulled by a capstan, and wound by a winding means. The drawing method of
A winding angle changing unit is provided in the passage of the coated optical fiber between the take-up capstan and the winding unit, and the winding of the coated optical fiber is performed by the winding angle changing unit.
It is characterized in that the pressing belt is moved away from the take-up capstan and the winding angle changing means adjusts the winding angle θ of the coated optical fiber in the take-up capstan.

The method for drawing an optical fiber according to a second aspect of the present invention is the method according to the first aspect of the present invention, wherein the winding angle changing means is a guide roller for guiding the coated optical fiber. When winding the fiber, the winding angle θ of the coated optical fiber in the take-up capstan is adjusted by moving the guide roller to change the distance between the guide roller and the take-up capstan.

The method for drawing an optical fiber according to the third aspect of the present invention is the method for drawing an optical fiber according to the second aspect of the present invention, in which the coated optical fiber is provided between the guide roller and the take-up capstan so that the distance between them is close. It is characterized in that the coated optical fiber is wound in a state of being sandwiched.

In the optical fiber drawing method according to the first aspect of the present invention, the winding angle changing means is provided in the passage of the coated optical fiber between the take-up capstan and the winding means. Then, when winding the coated optical fiber, the holding belt is pulled away from the capstan, and the winding angle changing means causes the winding angle of the coated optical fiber in the pulling capstan (hereinafter, simply referred to as a capstan winding angle) θ.
Perform with adjusting.

As described above, when the coated optical fiber is wound up, the coated optical fiber is pulled up without using the pressing belt, so that the surface of the coated optical fiber is not damaged by the fragments of the optical fiber stuck into the pressing belt. Absent. By adjusting the capstan winding angle θ, the frictional force between the take-up capstan and the coated optical fiber can be adjusted to a desired value, and slippage of the coated optical fiber in the take-up capstan can be eliminated. Therefore, it is possible to prevent the take-up efficiency of the coated optical fiber from being lowered by the take-up capstan, and reduce the measurement error of the winding length. In addition, since the pulling tension of the coated optical fiber by the pulling capstan can be stabilized, the fluctuation of the outer diameter of the optical fiber can be prevented.

In the optical fiber drawing method according to the second aspect of the present invention, the winding angle changing means is a guide roller for guiding the coated optical fiber. Then, when winding the coated optical fiber, the capstan winding angle θ is adjusted by moving the guide roller and changing the distance between the guide roller and the take-up capstan.

According to this optical fiber drawing method, in addition to the effect obtained by the invention according to claim 1, by shortening the distance from the take-up capstan to the guide roller, the take-up capstan generated at this portion. It is possible to suppress the vibration of the coated optical fiber due to the high-speed rotation, and increase the rotation speed of the take-up capstan to improve the productivity of the coated optical fiber. For example, the rotational speed of the take-up capstan, which was conventionally 1000 m / min or less, is 1500 in the invention according to claim 2 of the present application (for example, the optical fiber drawing device shown in FIG. 1).
It can be increased to about m / min.

In the optical fiber drawing method according to the third aspect of the present invention, the coated optical fiber is sandwiched between the guide roller and the take-up capstan so that the coated optical fiber is sandwiched therebetween. Take up.

Therefore, the coated optical fiber can be wound in a state where the capstan winding angle θ is always stable at a desired constant angle and the coated optical fiber is not separated from the guide roller. Moreover, the sandwiching pressure of the coated optical fiber between the guide roller and the take-up capstan can be increased, and as a result, the slip of the coated optical fiber at the take-up capstan can be further eliminated.

According to the third aspect of the present invention, when the guide roller is rotationally driven in the same direction as the take-up capstan or at a peripheral speed slightly higher than that of the take-up capstan, the coated optical fiber in the take-up capstan is formed. Since slack can be prevented, the risk of the coated optical fiber coming off the take-up capstan is reduced, which is preferable.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1, FIG. 2 (a), (b)
1 shows an optical fiber drawing device used in an optical fiber drawing method as an example of an embodiment of the present invention. However, description of the same parts as those in the conventional example shown in FIG. 5 is omitted. As shown in FIG. 1, this optical fiber drawing apparatus includes two sets of coating layer forming means 8 (resin coating die 9 and resin curing device 10),
An auxiliary resin curing device 10 'is provided, and a coated optical fiber 7 having two coating layers 6 and 6'can be manufactured.

Between the take-up capstan 12 and the dancer 15 of this optical fiber drawing device, a pulley-like member for guiding the coated optical fiber 7 to the dancer 15 is provided at a position A separated from the take-up capstan 12 by a distance a. A guide roller 14 is provided. This guide roller 14 is
From the position A, the distance b from the pick-up capstan 12
(However, b <a) can be reciprocated to a position B separated from each other.

This position A is the position of the conventional fixed guide roller 14, and the guide roller 1 at this position A is
When the coated optical fiber 7 is wire-wound on 4, the capstan winding angle θ becomes 100 °. On the other hand, position B
Is determined so that the capstan winding angle θ is about 180 °. In addition, the pressing belt 13
Can freely move in a direction away from or closer to the take-up capstan 12 (direction of a double arrow in FIG. 1).

A method for drawing the coated optical fiber 7 by the above-mentioned optical fiber drawing device and drawing the optical fiber 3 by the winding means 16 will be specifically described below. As shown in FIG. 1, first, the optical fiber preform 1 is heated and melted in the drawing furnace 2,
The optical fiber 3 was formed by drawing and cooled by the optical fiber cooler 5 below the drawing furnace 2.

Then, with the resin-coated die 9 removed from the passage of the optical fiber 3, the optical fiber 3 is
It was passed through the resin curing device 10 in the state of not being irradiated with ultraviolet rays, sandwiched between the take-up capstan 12 and the pressing belt 13, and then the take-up capstan 12 was driven to take out the optical fiber 3.

In this way, when the outer diameter of the optical fiber 3 reaches a desired value and stabilizes while the optical fiber 3 is being taken out by the capstan 12, the resin coating die 9 is attached to the passage of the optical fiber 3. The wire is threaded, an ultraviolet curable resin is supplied thereto, and ultraviolet irradiation is started from the resin curing device 10 serving as an ultraviolet irradiation source, and two coating layers 6 and 6 ′ are applied to the outside of the optical fiber 3. A coated optical fiber 7 was obtained.

Further, when the formation of the above-mentioned coating layers 6 and 6'starts, the pressing belt 13 is taken off and the capstan 1
2 in a direction away from the coated optical fiber 7, and the coated optical fiber 7 is pulled by the capstan 12 and then, as shown in FIG.
As shown in detail in (1), the guide roller 14 in the state of being moved to the position A was lined up and the winding was started by the winding means 16 via the dancer 15.

After that, as shown in detail in FIG.
The winding of the coated optical fiber 7 was continued in a state where the guide roller 14 was gradually moved to the position B to increase the capstan winding angle θ of the coated optical fiber 7. Thereby, the vibration of the coated optical fiber 7 after passing through the take-up capstan 12 can be eliminated and the slip of the coated optical fiber 7 at the take-up capstan 12 can be eliminated.

The coated optical fiber 7 obtained by the above-described method of drawing the optical fiber 3 according to the present embodiment is of a very high quality without any change in the outer diameter of the optical fiber 3. Further, since the guide roller 14 is provided as the winding angle changing means, the rotation speed of the take-up capstan 12 is 1500 when the coated optical fiber 7 is wound.
Coated optical fiber 7 in a stable state even if it is increased to m / min.
I was able to collect

Here, in the drawing method of the optical fiber 3 as an example of the present embodiment, the horizontally movable guide roller 14 is used as the winding angle changing means, but the optical fiber according to the first aspect of the present invention is used. The winding angle changing means in the drawing method of No. 3 is not limited to this, and may be, for example, the guide roller 14 that moves in the vertical direction, or as shown in FIG. It may be a metal ring 17 or the like that can be moved in the same manner as the guide roller 14 in a passed state.

In the example of this embodiment, the guide roller 14 has a pulley shape.
The guide roller 14 used in the method of drawing the optical fiber 3 of the invention described in 3 may be any one as long as it can adjust the capstan winding angle θ of the coated optical fiber 7, and for example, It may be a simple cylindrical roller.

In the drawing method of the optical fiber 3 as an example of the present embodiment, the position A and the position B are determined such that the capstan winding angle θ is 100 ° and 180 °, respectively. The method of drawing the optical fiber 3 according to the present invention is not limited to this. For example, in the example of the present embodiment, the moving range of the guide roller 14 is appropriately determined, and the coated optical fiber after passing through the take-up capstan 12 is appropriately determined. The vibration of the coated optical fiber 7 can be eliminated and the slippage of the coated optical fiber 7 in the take-up capstan 12 can be eliminated. However, when the winding angle of the coated optical fiber 7 on the guide roller 14 is large, for example, 180 °, the bending of the coated optical fiber 7 is reduced by increasing the outer diameter of the guide roller 14 to reduce the bending of the coated optical fiber 7. It is preferable to prevent the deterioration of quality.

However, since the coated optical fiber 7 is hooked on the guide roller 14 at the position A, it is better to pull the position A away from the capstan 12 and the dancer 16 to facilitate the hooking. preferable.

As shown in FIG. 4, the position B is set at a position close to the take-up capstan 12, and the coated optical fiber 7 is sandwiched between the guide roller 14 and the take-up capstan 12. The fiber 7 may be wound up.

In the example of the present embodiment, the example of the drawing method of the optical fiber 3 in which the two coating layer forming means 8 are provided and the two coating layers 6 (6 ') are provided on the optical fiber 3 is shown. The coated optical fiber 7 obtained by the drawing method of the optical fiber 3 of the present invention is not limited to the two-layer coating.

[0043]

According to the optical fiber drawing method of the present invention, the winding angle changing means is provided in the passage of the coated optical fiber between the take-up capstan and the winding means. Since the coated optical fiber can be taken out without using the holding belt, the coating layer of the coated optical fiber is not scratched by the fragments of the optical fiber piercing the holding belt, and the coated optical fiber on the take-up capstan is removed. High quality coated optical fiber can be obtained by eliminating fiber slip. According to the optical fiber drawing method of the invention described in claim 2 of the present application, in addition to the effect obtained by the invention of claim 1 of the present application, by shortening the distance from the take-up capstan to the guide roller, It is possible to suppress the vibration of the coated optical fiber due to the high-speed rotation of the take-up capstan generated at the portion, and it is possible to increase the rotation speed of the take-up capstan and improve the productivity of the coated optical fiber. According to the optical fiber drawing method of the invention of claim 3 of the present application, in addition to the effect obtained by the invention of claim 2 of the present application, the capstan winding angle θ is always more stable at a predetermined angle, and The coated optical fiber can be wound in a state where the coated optical fiber does not come off from the take-up capstan, and moreover, the sandwiching pressure between the guide roller and the take-up capstan can be adjusted. The effect that the slip can be further eliminated is obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an optical fiber drawing device used in an optical fiber drawing method as an example of an embodiment of the present invention in a partially sectional state.

2 is an explanatory view showing a part of a cross section of a take-off means and a guide roller in the optical fiber drawing device of FIG. 1, in which (a) is a state when a coated optical fiber is drawn;
(B) A state in which the coated optical fiber is wound after being wound.

FIG. 3 is a perspective view showing an example of a winding angle changing unit used in the optical fiber drawing method according to the embodiment of the present invention.

FIG. 4 is an explanatory view showing another embodiment of the take-out means and the guide roller shown in FIG. 2 (b).

FIG. 5 is an explanatory view showing an optical fiber drawing apparatus used in a conventional optical fiber drawing method in a partially cross-sectional state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber base material 2 Drawing furnace 3 Optical fiber 4 Outer diameter measuring instrument 5 Optical fiber cooler 6, 6'Coating layer 7 Coated optical fiber 8 Coating layer forming means 9 Resin coating die 10, 10 'Resin curing device 11, 11 'Take-up means 12 Take-up capstan 13, 13' Holding belt 14, 14 'Guide roller 15 Dancer 16 Wind-up means 17 Ring

Claims (3)

[Claims] 1. An optical fiber preform is obtained by heating an optical fiber preform to obtain an optical fiber, and after the optical fiber pulling step of pulling the optical fiber in a state of being sandwiched between a capstan and a pressing belt, the optical fiber is placed outside the optical fiber. A method for drawing an optical fiber, wherein a coated optical fiber is obtained by applying a coating layer, the coated optical fiber is drawn by a capstan, and wound by a winding means, the method comprising: between the take-up capstan and the winding means. In the passage of the coated optical fiber, a winding angle changing means is provided, the winding of the coated optical fiber is taken away from the capstan by a pressing belt, and the winding optical fiber is taken up by the winding angle changing means. It is characterized in that it is performed in a state where the winding angle θ of the optical fiber is adjusted. Line 引方 method of fiber. 2. The winding angle changing means is a guide roller for guiding the coated optical fiber, and when the coated optical fiber is wound, the guide roller is moved so that the gap between the guide roller and the take-up capstan is increased. The method of drawing an optical fiber according to claim 1, wherein the winding angle θ of the coated optical fiber in the take-up capstan is adjusted by changing 3. The line of the optical fiber according to claim 2, wherein the coated optical fiber is wound in a state where the guide roller and the take-up capstan are close to each other and the coated optical fiber is sandwiched therebetween. Pulling method.