JPH0952736A - Method for coating optical fiber and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a device capable of easily and uniformly applying a coating resin on an optical fiber under drawing at a high speed and at a low cost and a device capable of embodying this method. SOLUTION: This device has dies 17a, 23a to which the coating resin is supplied and which have nozzles to be passed with the optical fiber 12, tilting tables 18, 24 which hold these dies 17a, 23a and are tiltable with the plane perpendicular to the pass direction of the optical fiber 12, table tilting driving means 19, 25 for inclining the tilting tables 18, 24 in the arbitrary inclination positions and outside diameter measuring instruments 22, 27 which are disposed right under the tilting tables 18, 24 and measure the outside diameter of the optical fiber 12 coated with the coating resin without contact. The dies 17a, 23a are inclined at every prescribed angle with the plane perpendicular to the passable direction of the optical fiber 12 and the angle of inclination of the dies 17a, 23a at which the outside diameter of the optical fiber 12 is maximized and the fluctuation width thereof is minimized is selected. The dies 17a, 23a are held at this selected angle of inclination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus capable of uniformly coating a coating resin on an optical fiber.

[0002]

2. Description of the Related Art An optical fiber drawn from a drawing furnace is usually provided with a primary coating serving as a buffer layer with an ultraviolet curable resin or a silicone resin before coming into contact with any solid material such as a winding roller. Further, a secondary coating for reinforcement is applied with a thermoplastic resin such as an ultraviolet curable resin or nylon.

If the film thickness of the primary coating or the secondary coating formed on the optical fiber is not uniform, the microbending phenomenon, that is, irregularity is caused due to the fluctuation of the outside air temperature or the external force acting on the optical fiber. A slight bending occurs in the optical fiber, resulting in an increase in transmission loss of the optical fiber.
Further, when the film thickness of the primary coating or the secondary coating is non-uniform, there is a problem that the portion where the coating layer is thin has a relatively low strength and is easily broken from this portion.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 62-52143 and Japanese Patent Publication No. 5-37938, the eccentric state of the coating resin with respect to the optical fiber drawn from the drawing furnace is analyzed online. The position of the die is shifted or tilted so that the amount of eccentricity of the coating resin with respect to the optical fiber becomes smaller based on this.

[0005]

Problems to be Solved by the Invention JP-A-65-2214
As in Japanese Patent Publication No. 3 and Japanese Patent Publication No. 5-37938,
The eccentricity of the coating resin for the optical fiber drawn from the drawing furnace is optically grasped online, and based on this, the die position is shifted or tilted so that the amount of eccentricity of the coating resin for the optical fiber becomes smaller. In the method, the entire system including the light source, the optical device, and the image processing device becomes very large in order to grasp the eccentricity state, and there is a drawback that the manufacturing cost for that becomes very large.

A method of measuring the amount of eccentricity off-line is also conceivable, but it is necessary to stop the operating equipment and sample the sample each time the working conditions change, and it takes time to feed back the result. Therefore, it is difficult to efficiently manufacture the coating resin.

[0007] In recent years, with the lengthening of the base material for optical fibers,
The drawing speed is also increasing. When the optical fiber is drawn at such a high speed, the above-mentioned problems become more prominent, and therefore an alternative improvement plan has been demanded.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method by which a coating resin can be applied uniformly to an optical fiber being drawn at a high speed at a low cost, and an apparatus capable of realizing the method. .

[0009]

According to a first aspect of the present invention, an optical fiber is passed through a nozzle of a die to which a coating resin is supplied, and the coating resin is applied to the optical fiber. A step of inclining a predetermined angle with respect to a plane perpendicular to the passing direction of the optical fiber, and measuring the outer diameter of the optical fiber coated with the coating resin at each of the inclination angles in a non-contact manner; Of the die having the largest outer diameter and the smallest fluctuation range thereof, and holding the die at the selected inclination angle, the optical fiber coating method.

Here, the step of measuring the outer diameter of the optical fiber and the step of holding the die so that the outer diameter of the optical fiber is maximum and the fluctuation width thereof is minimum include the passing direction of the optical fiber. It is effective to perform respectively around two axes that are orthogonal to each other and mutually orthogonal, and in this case, the die is tilted by a predetermined angle around the first axis, and the outer diameter of the optical fiber is Select the inclination angle of the die around the first axis that has the maximum and minimum fluctuation width, hold the die at this inclination angle, and then incline the die around the second axis by a predetermined angle. It is desirable to select an inclination angle of the die around the second axis line in which the outer diameter of the optical fiber is maximum and the fluctuation range thereof is minimum, and the die is held at this inclination angle.

The coating resin may be a primary coating resin or a secondary coating resin applied to the optical fiber having the primary coating. further,
In a dual coating type coating apparatus in which the primary coating resin and the secondary coating resin are coated simultaneously, the primary coating resin and the secondary coating resin serve as the coating resin.

On the other hand, in the second embodiment of the present invention, a die having a nozzle through which the coating resin is supplied and through which the optical fiber passes, and a surface which holds the die and is perpendicular to the passing direction of the optical fiber. A tilt table that can tilt,
Table tilt drive means for tilting the tilt table to an arbitrary tilt position, and an outer diameter measuring device provided directly below the tilt table for measuring the outer diameter of the optical fiber coated with the coating resin in a non-contact manner. The optical fiber coating device is characterized by comprising:

Here, a table tilt control means for operating the table tilt drive means may be further provided, and the table tilt control means is an outer diameter of the optical fiber measured by the outer diameter measuring device. It is effective to actuate the table tilt drive means to tilt the tilt table together with the die so that the fluctuation range is maximum and the fluctuation range is minimum. Further, it is preferable that the tilt table tilts around two axes that are respectively orthogonal to the passing direction of the optical fiber and are orthogonal to each other.

Accordingly, the die is tilted together with the tilt table in advance by a predetermined angle with respect to the plane perpendicular to the passing direction of the optical fiber by using the table tilt driving means, and the optical fiber coated with the coating resin is tilted at each tilt angle. The outer diameter is measured with an outer diameter measuring device in a non-contact manner. Then, the inclination angle of the die is selected such that the outer diameter of the optical fiber is maximum and the fluctuation range thereof is minimum, and the die is held at the selected inclination angle and the coating resin is applied to the optical fiber.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an optical fiber manufacturing system capable of realizing an optical fiber coating method according to the present invention will be described in detail with reference to FIGS.

FIG. 1 showing a manufacturing system in this embodiment.
As shown in FIG. 1, the outer diameter of the drawn optical fiber 12 is measured below the optical fiber drawing furnace 13 which heats and melts the optical fiber preform 11 and draws the optical fiber 12 from the lower end thereof. The outer diameter measuring device 14 is disposed, and the detection information by the outer diameter measuring device 14 is output to the control device 15 and the outer diameter dimension of the optical fiber 12 measured by the first outer diameter measuring device 14. The control device 15 appropriately adjusts the winding speed of the optical fiber winding device 16, which will be described later, that is, the drawing speed of the optical fiber 12 such that

Immediately below the first outer diameter measuring device 14 is a primary coating resin coating device 17 for coating a primary coating resin.
The die 17a of the primary coating resin applying device 17 has a first axis line (hereinafter, referred to as an X-axis line) perpendicular to the passing direction of the optical fiber 12 and orthogonal to each other and a first axis line. A first tilt table 1 that can be tilted around two axes (hereinafter, referred to as Y axis).
8 is installed. This first tilt table 18
The table tilt drive device 19 is capable of tilting at predetermined angles (for example, 5 minutes) around the X-axis and the Y-axis.

In order to adjust the temperature of the optical fiber 12 sent from the optical fiber drawing furnace 13 to the primary coating resin coating device 17 to an appropriate temperature for coating the primary coating resin, the optical fiber drawing furnace is used in this embodiment. An optical fiber cooling device 20 is provided between 13 and the first outer diameter measuring device 14.

Immediately below the above-mentioned primary coating resin coating device 17, there is provided a primary coating resin curing furnace 21 for curing the primary coating resin coated on the optical fiber 12, and further the primary coating resin curing furnace 21. A second outer diameter measuring instrument 22 for measuring the outer diameter of the optical fiber 12 in a state where the primary coating resin is applied is arranged below. The information detected by the second outer diameter measuring device 22 is the information detected by the control device 15 described above.
It is designed to be output to.

Immediately below the second outer diameter measuring device 22, a secondary coating resin coating device 2 for further coating the outer periphery of the optical fiber 12 coated with the primary coating resin with a secondary coating resin.
3 are arranged. The basic structure of the secondary coating resin coating device 23 is exactly the same as that of the primary coating resin coating device 17, and the die 23 of the secondary coating resin coating device 23 is the same.
The a is mounted on a second tilt table 24 that is tiltable around the X-axis and the Y-axis that are orthogonal to the passing direction of the optical fiber 12 and are also orthogonal to each other. The second tilt table 24 can be tilted by a predetermined angle (for example, 5 minutes) around the X axis and the Y axis by a table tilt drive device 25.

A secondary coating resin curing furnace 26 for curing the secondary coating resin coated on the optical fiber 12 is provided immediately below the above-mentioned secondary coating resin coating device 23, and this secondary coating resin is further provided. A third outer diameter measuring device 27 for measuring the outer diameter of the optical fiber 12 in a state where the secondary coating resin is applied is arranged below the curing oven 26. The information detected by the third outer diameter measuring device 27 is also included in the second outer diameter measuring device 22.
Similarly to the above, the data is output to the control device 15 described above. Each of these outer diameter measuring devices 14, 22, and 27 measures the outer diameter dimension of the optical fiber 12 in a non-contact manner.

The optical fiber 12 which has passed through the third outer diameter measuring device 27 has the direction changing roll 28 located therebelow.
The optical fiber take-up device 16 is wound around the optical fiber take-up device 16 via the. A tension roll 29 is provided to alleviate the tension fluctuation of the optical fiber 12 due to the change.

The control device 15 includes the first outer diameter measuring device 1
The rotation speed of the take-up drum 16a of the optical fiber take-up device 16 is controlled via the drive motor 30 so that the detection value of the optical fiber take-up device 4 becomes constant.
9 and 25 are driven to tilt the tilt tables 18 and 24 by a predetermined angle around the X-axis and the Y-axis, respectively, and the detection values by the second and third outer diameter measuring instruments 22 and 27 are stored for each tilt angle. Then, the tilt angles of the tilt tables 18 and 24 at which the outer diameter of the optical fiber 12 is maximum and the fluctuation width thereof is minimum are extracted. Then, after the table tilt drive devices 19 and 25 are driven so as to have the extracted tilt angle, the actual wire drawing application work is performed.

As shown in FIG. 2 showing the procedure of the present invention, first, in the step S1, the tilt tables 18, 2 are set.
4 is set to the initial position, and in this step S2, the first tilting table 18 is tilted from this state around the X axis in the first direction in steps of 5'to 40 'from the initial position, for example. It is tilted in the direction opposite to the direction in 5'steps from the initial position to 40 ', and in step S3, the outer diameter dimension of the optical fiber 12 at each tilted position and its fluctuation range are stored. Then, in step S4, the tilt angle around the X-axis of the first tilt table 18 in which the outer diameter of the optical fiber 12 is maximum and the fluctuation range thereof is minimum is obtained, and in step S5, the first tilt table is obtained. 18 is set around the X-axis so that the inclination angle obtained in step S4 is obtained.

Next, at step S6, Y is returned from this state.
The first tilting table 18 is tilted about the axis in the second direction from the initial position in steps of 5'to 40 ', and in the direction opposite to the second direction from the initial position in steps of 4'.
The optical fiber 12 is tilted to 0 ', and the outer diameter of the optical fiber 12 at each tilted position and its fluctuation range are stored in step S7. Then, in the step of S8, the tilt angle around the Y-axis of the second tilt table 18 in which the outer diameter of the optical fiber 12 is the maximum and the fluctuation range thereof is the minimum is obtained, and in the step of S9, the second tilt table. 18 is set around the Y-axis so that the inclination angle obtained in step S8 is obtained.

Further, in step S10, the second tilt table 25 is tilted about the X-axis in the first direction from the initial position to 40 'in steps of, for example, 5', and further in the direction opposite to the first direction. 40 'to the initial position in 5'steps
And the outer diameter dimension of the optical fiber 12 at each tilt position and its fluctuation range are stored in step S11. Then, in the step of S12, the tilt angle around the X-axis line of the second tilt table 25 in which the outer diameter of the optical fiber 12 is the maximum and the fluctuation range thereof is the minimum is obtained, and in the step of S13, the second tilt table. 25 is set around the X axis so that the inclination angle obtained in step S12 is obtained.

Next, in step S14, the second tilt table 25 is tilted from this state around the Y-axis in the second direction in steps of 5 ', for example, from the initial position to 40'. 4'from the initial position in 5'steps in the opposite direction
The optical fiber 12 is tilted to 0 ', and the outer diameter dimension of the optical fiber 12 at each tilt position and its fluctuation range are stored in step S15. Then, in step S16, the optical fiber 1
The tilt angle around the Y-axis of the second tilt table 25 having the largest outer diameter of 2 and the smallest fluctuation range is obtained, and the second tilt table 25 is tilted at the step of S16 in the step of S17. After being set around the Y-axis line so as to form an angle, the drawing of the optical fiber 12 to be the actual product and the resin application work are started in step S18.

As a result, it is possible to stably manufacture a good optical fiber 12 in which the thickness of the coating resin is extremely small.

By the way, when the first tilting table 18 is tilted around the X-axis while drawing the optical fiber 12 at a low speed, for example, at a rate of 400 meters per minute, the tilting angle, the outer diameter of the optical fiber 12, and its value. FIG. 3 shows the relationship with the fluctuation range, and FIG. 4 shows the relationship between the tilt angle of the first tilt table 18 and the non-uniform thickness ratio of the coating resin with respect to the optical fiber 12 at this time.

As is apparent from these figures, the die 1 in which the outer diameter of the optical fiber 12 is maximum and the fluctuation width thereof is minimum.
7a, that is, the tilt angle of the first tilt table 18 is
It can be seen that the uneven thickness ratio of the coating resin with respect to the optical fiber 12 is also the minimum, and the coating resin is maintained at a uniform and constant film thickness. In this case, the optical fiber 12 is operated at high speed, for example,
A similar tendency is exhibited when the fiber is drawn at a rate of 00 meters, but as is clear from FIGS. 5 and 6, the first tilt table 18 in which the outer diameter of the optical fiber 12 is maximum and the fluctuation width thereof is minimum. The inclination angle of can be grasped more clearly.

From the above, the optical fiber 1 is initially used.
After performing steps S1 to S17 while drawing 2 at a low speed, the tilt positions of the tilt tables 18 and 25 are repeated with the tilt positions of the tilt tables 18 and 25 as initial positions. The tilting table 18 and 25 may be set to a smaller size, for example, by tilting in 1'steps to about 10 ', and the optimum tilting positions of the tilting tables 18 and 25 may be set more precisely.

[0032]

According to the optical fiber coating method of the present invention,
The die is tilted by a predetermined angle with respect to the plane perpendicular to the passing direction of the optical fiber, and the outer diameter of the optical fiber coated with the coating resin is measured at each tilt angle without contact. Since it is held at the die tilt angle that maximizes the fluctuation range and minimizes the fluctuation range, the drawing furnace can be used without using a light source, an optical device, and an image processing device for grasping the eccentricity state as in the past. The coating resin can be applied to the drawn optical fiber in a uniform film thickness.

In this case, it is not necessary to optically grasp the eccentricity state online and to shift or incline the position of the die so that the eccentricity of the coating resin with respect to the optical fiber becomes small on the basis of this. Therefore, the whole system can be made more compact than the conventional one, and the manufacturing cost therefor can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an embodiment of an optical fiber manufacturing system capable of realizing an optical fiber coating method according to the present invention.

FIG. 2 is a flowchart showing a work procedure in the embodiment shown in FIG.

FIG. 3 is a graph showing the relationship between the tilt angle of the tilt table and the outer diameter of the optical fiber during drawing at a low speed.

FIG. 4 is a graph showing the relationship between the inclination angle of the inclination table and the non-uniform wall thickness ratio of the optical fiber during drawing at a low speed.

FIG. 5 is a graph showing the relationship between the tilt angle of the tilt table and the outer diameter dimension of the optical fiber during drawing at high speed.

FIG. 6 is a graph showing the relationship between the tilt angle of the tilt table and the non-uniform wall thickness ratio of the optical fiber during drawing at high speed.

[Explanation of symbols]

 11 Optical Fiber Base Material 12 Optical Fiber 13 Optical Fiber Drawing Furnace 14 First Outer Diameter Measuring Device 15 Control Device 16 Optical Fiber Winding Device 16a Winding Drum 17 Primary Coating Resin Coating Device 17a Die 18 First Inclined Table 19 Table tilt drive device 20 Optical fiber cooling device 21 Primary coating resin curing furnace 22 Second outer diameter measuring device 23 Secondary coating resin coating device 23a Die 24 Second tilting table 25 Table tilt driving device 26 Secondary coating resin curing furnace 27 Third Outer Diameter Measuring Device 28 Direction Change Roll 29 Tension Roll 30 Drive Motor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Tsuchiya 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works

Claims (9)

[Claims] 1. A method of passing an optical fiber through a nozzle of a die to which a coating resin is supplied, and applying the coating resin to the optical fiber, wherein the die is predetermined with respect to a plane perpendicular to the passing direction of the optical fiber. Inclining by each angle, and measuring the outer diameter of the optical fiber coated with the coating resin at each of the inclination angles in a non-contact manner, and the outer diameter of the optical fiber is maximum and its fluctuation range is minimum. Selecting the tilt angle of the die and holding the die at this selected tilt angle. 2. The step of measuring the outer diameter of the optical fiber, and the step of holding the die so that the outer diameter of the optical fiber is maximum and the fluctuation range thereof is minimum, in the passing direction of the optical fiber. The optical fiber coating method according to claim 1, wherein the optical fiber coating method is performed around two axes that are orthogonal to each other and orthogonal to each other. 3. The tilt angle of the die about the first axis is selected such that the die is tilted about the first axis by a predetermined angle and the outer diameter of the optical fiber is maximum and the fluctuation range thereof is minimum. Then, after holding the die at this tilt angle, the die is tilted by a predetermined angle around the second axis line, and the second axis line in which the outer diameter of the optical fiber is maximum and the fluctuation range thereof is minimum. 3. The optical fiber coating method according to claim 2, wherein an inclination angle of the die around the die is selected, and the die is held at the inclination angle. 4. The optical fiber coating method according to claim 1, wherein the coating resin is a primary coating resin. 5. The light according to claim 1, wherein the coating resin is a secondary coating resin applied to the optical fiber having a primary coating. Fiber coating method. 6. A die having a nozzle through which the coating resin is supplied and through which the optical fiber passes, a tilt table which holds the die and can tilt with respect to a plane perpendicular to the passing direction of the optical fiber, and the tilt table. A table tilt drive means for tilting the table to an arbitrary tilt position, and an outer diameter measuring device provided directly below the tilt table for measuring the outer diameter of the optical fiber coated with the coating resin in a non-contact manner. An optical fiber coating device characterized by the above. 7. The optical fiber coating apparatus according to claim 6, further comprising table tilt control means for operating the table tilt drive means. 8. The table tilt control means operates the table tilt drive means so that the outer diameter of the optical fiber measured by the outer diameter measuring device is maximum and the fluctuation range thereof is minimum. The optical fiber coating device according to claim 7, wherein a tilting table is tilted together with the die. 9. The tilt table according to claim 6, wherein the tilt table is tilted about two axes that are respectively orthogonal to the passing direction of the optical fiber and are orthogonal to each other. The optical fiber coating device as described in any one.