JP2012025644A - Method and apparatus for producing optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for producing an optical fiber where the unintended twist of the optical fiber in one direction is released when rewinding the optical fiber.SOLUTION: In the method for producing the optical fiber having a step that the drawn and resin-coated optical fiber 10 is rewound on another rewinding bobbin 2 after being wound on a supply bobbin 1, the twisting state of the optical fiber 10 in one direction is monitored by an uneven thickness measuring sensor 7 set in a path line between the supply bobbin 1 and the rewinding bobbin 2 and the rotation of the supply bobbin 1 is controlled in a direction perpendicular to the unreeling direction of the optical fiber 10 so that the twist of the optical fiber 10 in one direction is released.

Description

  The present invention relates to an optical fiber manufacturing method and a manufacturing apparatus including a step of winding an optical fiber strand or a core wire that has been drawn and coated with a resin, and then winding it to another bobbin.

  The optical fiber is wound around a bobbin once the outer periphery of the drawn glass fiber is coated with a resin. After this, for example, there may be rewinding such as detection of defects in the resin coating of the optical fiber (cove detection), screening, coloring, and winding on a bobbin for shipment. Furthermore, after that, a plurality of optical fibers may be arranged in parallel to form a tape core wire by batch coating or a multi-core optical cable in which a plurality of optical fibers are assembled. In the following description, an optical fiber means an optical fiber (optical fiber strand) in a state where a protective coating is applied to a glass fiber immediately after drawing, and a state in which a colored layer for identification is applied to the optical fiber strand. In addition, the outer periphery of the glass fiber including the optical fiber (optical fiber core wire) and the like is pointed to one having a resin coating of one or more layers.

  When manufacturing the optical fiber, if the axis of the pass line of the equipment is shifted, if the roller in the pass line is tilted, if the fiber is uneven in one direction and a force is applied in a stable direction, etc. In some cases, a force for rotating the fiber is applied only in one direction. If a unidirectional force is applied in this way, the fiber will be twisted in one direction. When the fiber is unwound in the subsequent process, the fiber may become entangled and disconnected, or the tape core may be removed in the tape forming process. May twist. In order to reduce the polarization mode dispersion (PMD) value, it is known to intentionally twist the optical fiber in alternate directions, but when twisting in the alternate direction, the fiber is unwound. Since the twist is offset, the fiber will not become entangled.

  As a method for reducing PMD, for example, as in Patent Document 1, a bobbin for feeding out a plurality of optical fibers when taped into an optical fiber is rotated for each optical fiber in a direction perpendicular to the feeding direction of the optical fiber. It is disclosed to control the movement or to intentionally deviate the thickness of the resin coating of the optical fiber in the radial direction and to vary the length in the longitudinal direction of the optical fiber as in Patent Document 2. Patent Document 3 discloses an example of an optical fiber thickness deviation occurrence form and the thickness deviation detection using scattered light caused by laser light irradiation.

JP-A-8-43694 Japanese Patent Laid-Open No. 2004-38066 JP-A-60-235670

  Patent Documents 1 and 2 disclose a method for reducing (twisting) PMD. However, there is no disclosure of how to handle a twisted fiber in one direction. In Patent Document 1, the twist direction of each optical fiber is intentionally alternated so that no twist remains in the entire length of the optical fiber, but this originally causes twist in the optical fiber. It does not correspond to the case.

  On the other hand, in the process of manufacturing an optical fiber, apart from intentionally forming uneven thickness as in Patent Document 2, usually, uneven thickness often occurs naturally. As an example in which the uneven thickness of the optical fiber is generated, for example, as illustrated in Patent Document 3, it is generated depending on the state of the drawing equipment, the position of the die, and the like. In this case, the radial position of the uneven thickness is constant and often occurs continuously in the longitudinal direction. The thickness deviation is allowed within a predetermined range. However, if the thickness is largely uneven, it is detected by a thickness sensor or the like, and correction control is performed, or the die is reassembled.

  The optical fiber is wound around the bobbin through several guide rollers and the like, but when the guide roller is inclined, the optical fiber is twisted in one direction. FIG. 3 is a diagram for explaining the reason for the occurrence of the twist. The optical fiber 10 is guided by the guide groove 14 of the guide roller 13 and wound up. However, since the roller is inclined, the optical fiber 10 is wound while continuing to roll in one direction. It is done.

  If the optical fiber is twisted in one direction, the twisted state cannot be released because the both-end fixed state by the feeding-side bobbin and the winding-side bobbin does not change even in the subsequent rewinding process. For this reason, when an optical fiber in an unintentionally unidirectional twisted state is used to form a tape core wire, the tape core wire itself is twisted or tangled in the middle and disconnected, resulting in a defective product. Therefore, when the twisted state of the optical fiber is severe, it must be disposed of.

  The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an optical fiber manufacturing method and an apparatus for manufacturing the same, in which an unintended unidirectional twist of the optical fiber is released when the optical fiber is wound. And

  An optical fiber manufacturing method and manufacturing apparatus according to the present invention includes a step of winding an optical fiber, which has been drawn and coated with a resin, around a supply bobbin, and then winding the optical fiber onto another winding bobbin. The deviation measurement sensor provided in the pass line between the bobbin and the take-up bobbin monitors the unidirectional twist of the optical fiber, and the supply bobbin is connected to the optical fiber so that the unidirectional twist of the optical fiber is released. The rotation control is performed in a direction orthogonal to the feeding direction.

  According to the present invention, at the time of rewinding an optical fiber, one-way twisting of the optical fiber can be eliminated, making it possible to manufacture a tape core without twisting or breaking, and improving the productivity of the optical fiber. be able to.

It is a figure explaining the outline of the present invention. It is a figure explaining the unidirectional twist of an optical fiber, and the state of thickness deviation. It is a figure explaining generation | occurrence | production of the one way twist of an optical fiber.

  The outline of the present invention will be described with reference to FIG. In the figure, 1 is a supply bobbin, 2 is a take-up bobbin, 3 is a turntable, 4 is a guide roller, 5 and 6 are dancer rollers, 7 is a thickness measurement sensor, 7a is a laser light source, 7b is a photodetector, 8 Is a linear velocity detector, 9 is a control unit, and 10 is an optical fiber.

  FIG. 1 is an example showing the rewinding of the optical fiber 10 in the present invention, and the optical fiber 10 wound around the supply bobbin 1 is wound around the winding bobbin 2. The optical fiber 10 is, for example, one in which the outer periphery of a drawn glass fiber is coated with one or two layers of resin coating, and an unintended unidirectional twist is generated. The take-up bobbin 2 may be the same as the supply bobbin 1, but a plurality of bobbins having a smaller take-up amount than the supply bobbin 1 may be subdivided and taken up.

  The optical fiber 10 drawn out from the supply bobbin 1 is sent out to a pass line for rewinding through a plurality of guide rollers 4 and dancer rollers 5. Also on the winding side, the optical fiber 10 that has finished predetermined processing in the pass line is wound around the winding bobbin 2 with a predetermined tension through the plurality of guide rollers 4 and the dancer roller 6. The rotation of the supply bobbin 1 can be controlled by the turntable 3 in the direction indicated by the arrow a orthogonal to the feeding direction of the optical fiber 10.

  The present invention is characterized in that, when rewinding the optical fiber 10 or the like, an unintended unidirectional twisted state of the optical fiber is detected by monitoring the uneven thickness state, and this twist is eliminated. Therefore, the optical fiber which is the subject of the present invention is intended for an optical fiber with uneven thickness, and is excluded when the optical fiber is manufactured in an ideal state where the uneven thickness is zero. . Further, as disclosed in Patent Document 2, an optical fiber that is intentionally provided with a thickness deviation along the longitudinal direction and cannot detect a twist due to the thickness deviation is also excluded from the scope of the present invention.

In the present invention, an uneven thickness measurement sensor 7 for monitoring the uneven thickness state is arranged in a pass line such as rewinding of the optical fiber 10. The uneven thickness measurement sensor 7 includes, for example, a laser light source 7a that irradiates the side surface of the optical fiber and a photodetector 7b that includes a diode array that detects transmitted light or reflected light from the side surface of the optical fiber. The uneven thickness measurement sensor is not limited to this configuration, and may be configured to irradiate X-rays or take a picture with a camera. Further, the rewinding linear velocity of the optical fiber 10 is measured by the linear velocity detector 8. The measured thickness deviation states and linear velocity of the fiber-optic 1 0 is monitored by the control unit 9, the monitor result is fed back to the turntable 3 of the supply bobbin.

  FIG. 2 (A) is a diagram showing an uneven thickness state of the optical fiber 10, and the optical fiber 10 has a helical twist in one direction along the longitudinal direction for the reason described in FIG. To do. However, since the resin coating 12 of the optical fiber 10 has a cylindrical shape and the external shape in the longitudinal direction does not change, the glass fiber 11 is displaced in a spiral manner within the resin coating 12. Here, the twisting amount of the optical fiber 10 is T (times / m), and the linear velocity V (m / min) for rewinding the optical fiber 10 is used.

  When the optical fiber 10 having the twist amount T in one direction is traveling in the rewinding direction at the linear velocity V, when the variation state of the cross section of the optical fiber 10 at the fixed position bb is observed, the resin coating The position of the outer peripheral surface showing the outer diameter of 12 does not vary. However, as shown in FIG. 2B, the position of the glass fiber 11 varies so as to rotate in one direction as indicated by an arrow d. The rotational fluctuation number n (rpm) of the glass fiber 11 at this time is a product (T × V) of the twist amount T and the linear velocity V.

As shown in FIG. 2C, the rotational fluctuation number n can be detected by the above-described thickness detection sensor. That is, when the rotational fluctuation state of the glass fiber 11 of the traveling optical fiber 10 shown in FIG. 2B is observed from the side, the position of the glass fiber 11 is indicated by the arrow e in the radial direction of the optical fiber on the observation surface. It fluctuates to vibrate. The fluctuation frequency n ′ is the same frequency as the rotation fluctuation number n (rpm) in FIG. By monitoring the frequency n ′, the twist amount T (times / m) of the optical fiber 10 can be estimated.
For example, when T = 10 times / m and V = 3000 m / min, n = n ′ = 30000 (rpm). That is, the fluctuation frequency of the glass fiber 11 monitored by the thickness deviation measuring sensor is n / 60 = 500 (Hz).

  Returning to FIG. 1, the present invention will be described. The frequency n ′ of the glass fiber 11 of the optical fiber 10 detected by the thickness deviation measuring sensor 7 is input to the control unit 9. The rewinding linear velocity V of the optical fiber 10 is detected by the linear velocity detector 8 and input to the control unit 9. The control unit 9 outputs a control signal calculated based on the data such as the frequency n ′ and the linear velocity V, and drives and controls the turntable 3 of the supply bobbin 1.

  The rotation of the turntable 3 applies a twist to the optical fiber 10 fed from the supply bobbin 1 or cancels the twist applied to the optical fiber 10 (returns the twist). That is, when the optical fiber 10 is twisted, the twist of the optical fiber 10 can be released by rotating the turntable 3 at a rotation speed N (rpm) according to the feeding speed of the optical fiber 10. it can.

  Specifically, the twist direction of the optical fiber is confirmed in advance, and the rotation direction of the turntable 3 is set to a direction to eliminate the twist. Then, the rotational speed N of the turntable 3 is controlled so that the vibration frequency n ′ detected by the uneven thickness measurement sensor 7 becomes zero. When the turntable 3 is rotated in either direction and the frequency n ′ increases, it is determined that the rotation direction is opposite, and the rotation of the optical fiber is controlled by performing rotation control in the opposite direction. The twist can be eliminated.

  In addition, the above-described unidirectional twist release of the optical fiber can be performed at the time of rewinding such as bump detection, screening, coloring, and dividing into a plurality of bobbins in the optical fiber, thereby increasing the work process. Can be implemented without. By using an optical fiber that is free from unidirectional twisting, it becomes possible to make a tape core, and even if the optical fiber has a large twist, there is no need to dispose of it, thereby improving the productivity of the optical fiber. Can do.

DESCRIPTION OF SYMBOLS 1 ... Supply bobbin, 2 ... Winding bobbin, 3 ... Turntable, 4 ... Guide roller, 5 ... 6 Dancer roller, 7 ... Thickness measuring sensor, 7a ... Laser light source, 7b ... Photo detector, 8 ... Linear velocity Detector: 9 ... Control part, 10 ... Optical fiber, 11 ... Glass fiber, 12 ... Resin coating, 13 ... Guide roller, 14 ... Guide groove.

Claims (2)

An optical fiber manufacturing method comprising a step of winding an optical fiber that has been drawn and coated with a resin coating around a supply bobbin and then rewinding it to another winding bobbin,
By the thickness measurement sensor provided in the pass line between the supply bobbin and the winding bobbin, the unidirectional twist state of the optical fiber is monitored, and the unidirectional twist of the optical fiber is released. The method of manufacturing an optical fiber, wherein the supply bobbin is rotationally controlled in a direction orthogonal to a feeding direction of the optical fiber. An optical fiber manufacturing apparatus comprising means for winding an optical fiber that has been drawn and coated with a resin coating onto a supply bobbin and then rewinding it to another winding bobbin,
In the pass line between the supply bobbin and the take-up bobbin, an uneven thickness measurement sensor that monitors the unidirectional twist state of the optical fiber is disposed, so that the unidirectional twist of the optical fiber is released, An apparatus for manufacturing an optical fiber, comprising: control means for controlling rotation of the supply bobbin in a direction orthogonal to a feeding direction of the optical fiber.

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