Method for manufacturing optical fibers, and apparatus for manufacturing optical fibers

Abstract

To appropriately control cooling of an optical fiber bare wire by using a non-contact guide.SOLUTION: A method of manufacturing an optical fiber includes the steps of: melting an optical fiber base material and wiredrawing an optical fiber bare wire; changing a direction of the optical fiber bare wire by a plurality of non-contact guides while cooling the optical fiber bare wire by the plurality of non-contact guides; and coating the optical fiber bare wire with a resin. Each of the non-contact guides has, along its outer peripheral surface, a guide part around which a part of the optical fiber bare wire can be wound. The guide part is provided with a blow-out port which blows out gas for making the optical fiber bare wire float. Cooling of the optical fiber bare wire is controlled by adjusting a position of at least one of the plurality of non-contact guides to increase or decrease a winding length of the optical fiber bare wire with respect to the plurality of non-contact guides.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an optical fiber and an apparatus for manufacturing an optical fiber.

Background Art

[0002] Patent Document 1 discloses an example of a method for manufacturing an optical fiber. In this manufacturing method, an optical fiber preform is melted and drawn, and a coating resin is provided on the outer periphery of the drawn optical fiber bare wire. The drawn optical fiber bare wire is cooled while being changed in direction by a direction changer (non-contact guide) before being coated with resin. During this cooling, the position of the non-contact guide is horizontally moved based on the outer diameter value of the coating resin of the optical fiber bare wire, thereby adjusting the length of the optical fiber bare wire between the non-contact guides.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the method of simply adjusting the length of the optical fiber bare wire between the non-contact guides, the variation range of the cooling degree of the optical fiber bare wire is small, and it may be difficult to achieve the desired cooling efficiency. In addition, there are many cases where the size of the equipment is spatially limited, and the non-contact guide may not be able to traverse largely in the horizontal direction. Therefore, a technique that can appropriately control the cooling of the optical fiber bare wire with compact equipment is desired.

[0005] An object of the present disclosure is to provide a method for manufacturing an optical fiber and an apparatus for manufacturing an optical fiber that can appropriately control the cooling of an optical fiber bare wire in a method for cooling an optical fiber bare wire using a non-contact guide.

Means for Solving the Problems

[0006] This disclosure provides a method for manufacturing an optical fiber. The method for manufacturing an optical fiber comprises the steps of: melting an optical fiber base material to draw an optical fiber bare wire; cooling the optical fiber bare wire with a plurality of non-contact guides while changing its direction with a plurality of non-contact guides; and coating the optical fiber bare wire with a resin. Each non-contact guide has a guide portion along its outer surface to which a portion of the optical fiber bare wire can be wound, and the guide portion is provided with an outlet for blowing out gas to suspend the optical fiber bare wire. The position of at least one of the plurality of non-contact guides is adjusted to change the direction of the optical fiber bare wire with respect to the plurality of non-contact guides This is the length of the portion that comes into direct contact with the gas from multiple non-contact guides. The cooling of the bare optical fiber is controlled by increasing or decreasing the winding length. Among the multiple non-contact guides, adjacent non-contact guides in the direction of travel of the bare optical fiber are separated vertically. The multiple non-contact guides are arranged at regular intervals such that the pitch width H between the multiple non-contact guides is greater than the outer diameter D2 of each of the multiple non-contact guides.

[0007] This disclosure provides an apparatus for manufacturing optical fibers. The apparatus for manufacturing optical fibers comprises a melting apparatus, a cooling mechanism, and a coating apparatus. The melting apparatus melts the optical fiber matrix to draw bare optical fibers from the optical fiber matrix. The cooling mechanism cools the bare optical fibers. The coating apparatus coats the bare optical fibers with resin. The cooling mechanism has a plurality of non-contact guides that change the direction of travel of the bare optical fibers. Each non-contact guide has a guide portion along its outer surface on which a portion of the bare optical fiber can be wound, and the guide portion is provided with an outlet for blowing gas to suspend the bare optical fiber. At least one of the plurality of non-contact guides has a guide portion for the bare optical fiber This is the length of the portion that comes into direct contact with the gas from multiple non-contact guides. This is a movable, non-contact guide that can be adjusted to increase or decrease its wrapping length. Among the multiple non-contact guides, adjacent non-contact guides in the direction of travel of the bare optical fiber are separated vertically. The multiple non-contact guides are arranged at regular intervals such that the pitch width H between the multiple non-contact guides is greater than the outer diameter D2 of each of the multiple non-contact guides. [Effects of the Invention]

[0008] According to this disclosure, the cooling of bare optical fibers using a non-contact guide can be appropriately controlled. [Brief explanation of the drawing]

[0009] [Figure 1]Figure 1 is a schematic diagram of an optical fiber manufacturing apparatus according to one embodiment. [Figure 2] Figure 2 is a perspective view showing the non-contact guide of the optical fiber manufacturing apparatus shown in Figure 1. [Figure 3] Figure 3 shows the internal space shown in Figure 1, before the bare optical fiber is wound around the non-contact guide. [Figure 4] Figure 4 shows the state in which a bare optical fiber is wound around a non-contact guide in the internal space shown in Figure 1. [Figure 5] Figure 5 shows two non-contact guides that are adjacent in direction X, among the multiple non-contact guides shown in Figure 4. [Figure 6] Figure 6 is a graph showing the relationship between cooling distance and fiber temperature. [Figure 7] Figure 7 is a graph showing the relationship between traverse distance and total wrap length. [Figure 8] Figure 8 is a graph showing the relationship between traverse distance and total air length. [Figure 9] Figure 9 is a graph showing the relationship between traverse distance and total wrap-around length. [Figure 10] Figure 10 shows the state in which a bare optical fiber is wound around a non-contact guide in the internal space of the optical fiber manufacturing apparatus according to the first modified example. [Figure 11] Figure 11 shows the state in which a bare optical fiber is wound around a non-contact guide in the internal space of the optical fiber manufacturing apparatus according to the second modified example. [Modes for carrying out the invention]

[0010] [Description of Embodiments in this Disclosure] First, the contents of the embodiments of this disclosure will be listed and described. One embodiment of a method for manufacturing an optical fiber comprises the steps of: melting an optical fiber base material to draw an optical fiber bare wire; cooling the optical fiber bare wire with a plurality of non-contact guides while changing its direction with a plurality of non-contact guides; and coating the optical fiber bare wire with a resin. Each non-contact guide has a guide portion along its outer surface to which a part of the optical fiber bare wire can be wound, and the guide portion is provided with an outlet for blowing out gas to suspend the optical fiber bare wire. The position of at least one of the plurality of non-contact guides is adjusted to control the direction of the optical fiber bare wire with respect to the plurality of non-contact guides This is the length of the portion that comes into direct contact with the gas from multiple non-contact guides. The cooling of the bare optical fiber is controlled by increasing or decreasing the winding length. Among the multiple non-contact guides, adjacent non-contact guides in the direction of travel of the bare optical fiber are separated vertically. The multiple non-contact guides are arranged at regular intervals such that the pitch width H between the multiple non-contact guides is greater than the outer diameter D2 of each of the multiple non-contact guides.

[0011] In this optical fiber manufacturing method, the direction of the bare optical fiber is changed via multiple non-contact guides, and the position of the multiple non-contact guides is adjusted to increase or decrease the winding length of the bare optical fiber, that is, the length of the portion of the bare optical fiber that is more directly exposed to the gas from the non-contact guides. Increasing or decreasing the winding length of the bare optical fiber in this way has a greater effect on the cooling efficiency than increasing or decreasing the length of the bare optical fiber in air between each non-contact guide, that is, the length of the portion that simply passes through the gas atmosphere. Therefore, according to the above manufacturing method, the cooling efficiency of the bare optical fiber can be adjusted over a wider range, and the cooling of the bare optical fiber can be appropriately controlled. Furthermore, because the non-contact guides are spaced apart, the angle at which the direction of travel of the bare optical fiber, as it is drawn from one non-contact guide and enters the next, is inclined relative to the horizontal can be changed according to the traverse distance of the non-contact guides along the horizontal direction. This allows for easy increases or decreases in the length of the bare optical fiber wrapped around the non-contact guides. As a result, the cooling of the bare optical fiber can be appropriately controlled.

[0012] In one embodiment, at least one of the multiple non-contact guides may be a movable non-contact guide capable of traversing along the horizontal direction. In this embodiment, the cooling of the bare optical fiber may be controlled by adjusting the traverse distance of the movable non-contact guide to increase or decrease the wrapping length. In this case, the movable non-contact guide moves along the horizontal direction. Therefore, compared to the case where the movable non-contact guide moves in an irregular direction, it is easier to calculate the wrapping length of the bare optical fiber and to control the cooling of the bare optical fiber.

[0013] As one embodiment, the plurality of non-contact guides may be three or more odd-numbered non-contact guides. In this form, the moving non-contact guide located at the even number from the optical fiber base material among the plurality of non-contact guides is traversed along the horizontal direction to increase or decrease the winding length. In this case, the in-line position of the optical fiber bare wire with respect to the non-contact guide closest to the apparatus for melting the optical fiber base material (which side of the non-contact guide to contact) and the out-line position of the optical fiber bare wire with respect to the non-contact guide closest to the apparatus for coating the optical fiber bare wire can be aligned on the same side. Thereby, the winding length management becomes easy.

[0014] As one embodiment, the plurality of non-contact guides may be four or more non-contact guides. Among the plurality of non-contact guides, the non-contact guides excluding the first non-contact guide closest to the optical fiber base material and the second non-contact guide closest to the apparatus for coating with resin are moving non-contact guides. The moving non-contact guide located at the odd number from the optical fiber base material and the moving non-contact guide located at the even number from the optical fiber base material may traverse in different directions from each other in the horizontal direction and at substantially the same distance to increase or decrease the winding length. In this case, the length of the optical fiber bare wire between the non-contact guides excluding the first non-contact guide and the second non-contact guide becomes substantially the same, and the total winding length of the optical fiber bare wire (the total value of the winding lengths of the optical fiber bare wire for each non-contact guide) can be easily calculated. Therefore, it is easy to appropriately control the cooling of the optical fiber bare wire.

[0015] As one embodiment, the traverse distance of the moving non-contact guide may be greater than 0 mm and 350 mm or less. In this case, since the traverse distance is 350 mm or less, the enlargement of the cooling mechanism of the optical fiber can be suppressed. Further, when the traverse distance is 350 mm or less, the variation amount of the total winding length of the optical fiber bare wire with respect to the variation amount of the traverse distance is large. Therefore, the cooling efficiency of the optical fiber bare wire can be greatly adjusted by a slight increase or decrease operation of the traverse distance, and the cooling of the optical fiber bare wire can be efficiently controlled.

[0016] In one embodiment, when the traverse of the moving non-contact guide is completed, a virtual line extending vertically downward from the non-contact guide closest to the optical fiber base material among the multiple non-contact guides coincides with a virtual line extending vertically downward from the non-contact guide closest to the resin coating device among the multiple non-contact guides. In this case, it becomes easier to manage the length of the bare optical fiber wrapped around the non-contact guide, and the cooling of the bare optical fiber can be controlled more appropriately.

[0017] In one embodiment, the movable non-contact guide may be arranged to traverse a virtual line extending vertically downward from the non-contact guide closest to the optical fiber base material among a plurality of non-contact guides. In this case, the range of increase or decrease in the length wrapped around the non-contact guide can be increased, and the cooling of the bare optical fiber can be efficiently controlled. In addition, the size of the optical fiber cooling device can be suppressed.

[0019] In one embodiment, the cooling of a bare optical fiber can be controlled by increasing or decreasing the length of the bare optical fiber wrapped around a non-contact guide, and the adjustment of the wrapping length may be performed during the process of cooling the bare optical fiber. When cooling control is performed while the bare optical fiber is being cooled, the cooling control of the bare optical fiber can be performed at a more appropriate timing, and a higher precision optical fiber can be obtained. In addition, it is possible to measure in advance how much the wrapping length should be increased or decreased before performing the cooling process in the actual manufacturing process, in which case it is not necessary to perform cooling control each time during manufacturing, thus simplifying the manufacturing method.

[0020] An optical fiber manufacturing apparatus according to one embodiment comprises a melting apparatus, a cooling mechanism, and a coating apparatus. The melting apparatus melts the optical fiber base material to draw bare optical fiber wires from the optical fiber base material. The cooling mechanism cools the bare optical fiber wires. The coating apparatus coats the bare optical fiber wires with resin. The cooling mechanism has a plurality of non-contact guides that change the direction of travel of the bare optical fiber wires. Each non-contact guide has a guide portion along its outer surface to which a portion of the bare optical fiber wire can be wound, and the guide portion is provided with an outlet for blowing out gas to suspend the bare optical fiber wire. At least one of the plurality of non-contact guides has a guide portion for the bare optical fiber wire This is the length of the portion that comes into direct contact with the gas from multiple non-contact guides. This is a movable, non-contact guide that can be adjusted to increase or decrease its wrapping length. Among the multiple non-contact guides, adjacent non-contact guides in the direction of travel of the bare optical fiber are separated vertically. The multiple non-contact guides are arranged at regular intervals such that the pitch width H between the multiple non-contact guides is greater than the outer diameter D2 of each of the multiple non-contact guides.

[0021] This optical fiber manufacturing apparatus allows for increasing or decreasing the winding length of the bare optical fiber by adjusting the positions of multiple non-contact guides. As mentioned above, increasing or decreasing the winding length of the bare optical fiber has a greater impact on cooling efficiency than increasing or decreasing the air length of the bare optical fiber between each non-contact guide. Therefore, by using the above manufacturing apparatus, the cooling efficiency of the bare optical fiber can be adjusted over a wider range, and the cooling of the bare optical fiber can be appropriately controlled. Because the non-contact guides are spaced apart, the angle at which the direction of travel of the bare optical fiber, as it is drawn from one non-contact guide and enters the next, is inclined relative to the horizontal can be changed according to the traverse distance of the non-contact guides along the horizontal. This allows for easy increases or decreases in the length of the bare optical fiber wrapped around the non-contact guides. Therefore, the cooling of the bare optical fiber can be appropriately controlled.

[0022] In one embodiment of an optical fiber manufacturing apparatus, the apparatus may further include a device for traversing a movable non-contact guide. The movable non-contact guide may be capable of traversing along a horizontal direction. Multiple non-contact guides may be arranged to control the cooling of the bare optical fiber by adjusting the traverse distance of the movable non-contact guide to increase or decrease the winding length. In this case, the non-contact guide moves along a horizontal direction. Therefore, compared to the case where the non-contact guide moves in an irregular direction, it is easier to calculate the winding length of the bare optical fiber and to control the cooling of the bare optical fiber.

[0023] In one embodiment of an optical fiber manufacturing apparatus, the moving non-contact guide may be arranged to traverse a virtual line extending vertically downward from the non-contact guide closest to the optical fiber base material among a plurality of non-contact guides. In this case, the range of increase or decrease in the length wrapped around the non-contact guide can be increased, and the cooling of the bare optical fiber can be efficiently controlled. In addition, the size of the optical fiber cooling device can be suppressed.

[0025] In one embodiment of the optical fiber manufacturing apparatus, the cooling mechanism may have 3 to 15 non-contact guides. In this case, having 3 or more non-contact guides allows for adjustment of the total winding length of the bare optical fiber. Furthermore, having 15 or fewer non-contact guides can suppress the need for larger optical fiber manufacturing apparatus.

[0026] In one embodiment of the optical fiber manufacturing apparatus, the winding diameter of each non-contact guide may be 50 mm or more and 200 mm or less. In this case, by having a winding diameter of 50 mm or more for each non-contact guide, a sufficient winding length of the bare optical fiber can be secured for each non-contact guide, and the cooling of the bare optical fiber can be appropriately controlled. Furthermore, by having a winding diameter of 200 mm or less for each non-contact guide, it is possible to suppress the increase in size of the optical fiber manufacturing apparatus.

[0027] [Details of the embodiments of this disclosure] Specific examples of optical fiber manufacturing apparatus and optical fiber manufacturing method relating to this disclosure will be described below with reference to the drawings. In the following description, the same reference numerals will be used for elements that are the same or have the same function, and redundant descriptions will be omitted. However, the present invention is not limited to these examples and is intended to include all modifications within the meaning and scope equivalent to the claims as indicated by the claims.

[0028] Referring to Figures 1 and 2, an optical fiber manufacturing apparatus and a method for manufacturing an optical fiber according to one embodiment will be described. Figure 1 is a schematic diagram of the optical fiber manufacturing apparatus 1 according to one embodiment. Figure 2 is a perspective view showing the non-contact guide 20. In this embodiment, the height direction (vertical direction) of the manufacturing apparatus 1 is denoted as direction X, the width direction (horizontal direction) as direction Y, and the depth direction as direction Z. In this embodiment, directions X, Y, and Z are orthogonal to each other.

[0029] As shown in Figure 1, the manufacturing apparatus 1 is a device that manufactures optical fiber strands 11 by heating and melting an optical fiber base material 2 to draw an optical fiber bare wire 10, and then applying a coating resin to the outer circumference of the optical fiber bare wire 10. As shown in Figure 1, the manufacturing apparatus 1 is equipped with a drawing furnace 3, a cooling section 4, a coating section 5, a curing section 6, a direct roller 7, a traction roller 8, and a winding section 9 in order along the passage path of the optical fiber bare wire 10 and optical fiber strands 11. The manufacturing apparatus 1 is also equipped with a traverse device 50.

[0030] The drawing furnace 3 is a melting device that heats and melts the optical fiber preform 2. The drawing furnace 3 heats and melts the optical fiber preform 2 so that it can be drawn along the vertical direction (direction X shown in Figure 1). The drawing furnace 3 has heaters located around the optical fiber preform 2. The optical fiber preform 2 may be a glass body (preform) containing, for example, quartz glass. The drawn optical fiber preform 2 becomes a bare optical fiber wire 10. The bare optical fiber wire 10 may be a glass wire containing, for example, a core and a cladding covering the outer circumference of the core. The drawn bare optical fiber wire 10 is sent to the cooling unit 4.

[0031] The cooling unit 4 is a cooling mechanism for cooling the bare optical fiber 10. The cooling unit 4 has an internal space S surrounded by an outer wall (including side walls, top plate, and bottom plate), through which the bare optical fiber 10 passes. The presence of an outer wall in the cooling unit 4 prevents the broken bare optical fiber 10 from scattering and also suppresses the accumulation of foreign matter in the internal space S, thereby maintaining the cleanliness of the internal space S. The outer wall of the cooling unit 4 may be made of transparent glass or resin so that the inside of the cooling unit 4 can be seen.

[0032] The cooling unit 4 may have an intake port (not shown) for injecting a dry gas into the internal space S to cool the bare optical fiber 10 overall. The heat of the bare optical fiber 10 is released to the outside using the dry gas as a coolant. The cooling unit 4 may also have an exhaust port (not shown) for discharging the dry gas. The height of the cooling unit 4 in direction X (height of the side wall) may be, for example, 1000 mm or more and 1600 mm or less. The width of the cooling unit 4 in direction Y (width of the side wall) may be, for example, 800 mm or more and 1400 mm or less. By enclosing the cooling unit 4 with an outer wall, it is possible to control the dew point inside the cooling unit 4 and prevent the scattering of optical fibers in the event of a break. However, it is also possible to cool the bare optical fiber 10 simply by using the non-contact guide 20 described later, without enclosing it with an outer wall. Furthermore, even if it is enclosed with an outer wall, it is also possible to simply prevent the bare optical fiber 10 from directly coming into contact with the outside air without injecting a dry gas into the internal space S.

[0033] The bare optical fiber 10 passes through the internal space S in a meandering manner, its direction of travel being changed by a plurality of non-contact guides 20. The bare optical fiber 10 passes between each non-contact guide 20 in a direction inclined with respect to directions X and Y. The cooling unit 4 has nine non-contact guides 21 to 29. Each non-contact guide 21 to 29 is provided sequentially along the path of the bare optical fiber 10. Hereafter, unless it is necessary to explain each non-contact guide 21 to 29 separately, they will simply be referred to collectively as the non-contact guides 20. The number of non-contact guides 20 in the cooling unit 4 may be multiple, and is not limited to nine. For example, the cooling unit 4 may have three to fifteen non-contact guides 20.

[0034] The non-contact guide 20 is a component that changes the direction of travel of the bare optical fiber 10. As shown in Figure 2, the non-contact guide 20 comprises a first flange 30 and a second flange 35. The first flange 30 and the second flange 35 are disc-shaped components and are arranged to overlap each other in a direction along the central axis C. The non-contact guide 20 has a guide portion 40 between the first flange 30 and the second flange 35. The guide portion 40 is a gap provided between the outer edge of the first flange 30 and the outer edge of the second flange 35. The guide portion 40 is provided in an annular shape along the outer circumference of the non-contact guide 20. The bare optical fiber 10 passes through the guide portion 40.

[0035] Internal components (not shown) are housed inside the first flange 30 and the second flange 35. These internal components are connected to an external gas supply source (such as an air pump). The internal components blow the gas supplied from the gas supply source out of the non-contact guide 20 through an outlet inside the guide section 40. The gas supplied from the gas supply source may be, for example, a dry gas filling the internal space S (see Figure 1) of the cooling section 4. The blown-out gas is blown onto the bare optical fiber 10 that is passed through the guide section 40. The bare optical fiber 10 is suspended by the blown gas and does not come into contact with the first flange 30 and the second flange 35.

[0036] The second flange 35 may be movably attached to the internal member. In this case, the pressure of the gas blown out from the guide portion 40 can be adjusted by moving the second flange 35 to change the width of the guide portion 40. The pressure of the gas blown out from the guide portion 40 may be appropriately adjusted according to the diameter or type of the bare optical fiber 10 passed through the guide portion 40. The first flange 30 may be fixed to the internal member, or, similar to the second flange 35, it may be attached to the internal member so as to be movable in the direction that changes the width of the guide portion 40.

[0037] At least one of each non-contact guide 20 is a movable non-contact guide that can move along direction Y across the internal space S. In the optical fiber manufacturing process, the position of at least one of the multiple non-contact guides 20 is adjusted to increase or decrease the length of the wrapped optical fiber 10 around the non-contact guide 20. This controls the cooling of the optical fiber 10. The wrapped length of the optical fiber 10 is the length of the portion of the optical fiber 10 that is passed through the guide portion 40 and is located on an arc centered on the central axis C of the non-contact guide 20 (hereinafter referred to as the wrapped portion).

[0038] In this embodiment, the even-numbered non-contact guides 20 (non-contact guides 22, 24, 26, and 28) are moved along direction Y toward the right side of the paper in Figure 1. The even-numbered non-contact guides 20 are the non-contact guides 20 located in even positions from the optical fiber base material 2, and are counted in even positions when the non-contact guides 20 are counted in the order in which the bare optical fiber 10 passes. On the other hand, the odd-numbered non-contact guides 20 are the non-contact guides 20 located in odd positions from the optical fiber base material, and are counted in odd positions when the non-contact guides 20 are counted in the order in which the bare optical fiber 10 passes. In this embodiment, the odd-numbered non-contact guides 20 are the non-contact guides 21, 23, 25, 27, and 29.

[0039] The manufacturing apparatus 1 includes a traverse device 50 that traverses each non-contact guide 20. Here, traversing the non-contact guide 20 means moving the non-contact guide 20 along direction Y (horizontal direction). That is, the traverse device 50 is configured to allow each non-contact guide 20 to move along direction Y (horizontal direction). Each non-contact guide 20 is attached to the traverse device 50. Each non-contact guide 20 may be detachable from the traverse device 50. That is, the number of non-contact guides 20 in the cooling unit 4 may be changeable. By changing the number of non-contact guides 20, the total winding length of the bare optical fiber 10 around the non-contact guides 20 can be adjusted. The total winding length of the bare optical fiber 10 is the sum of the winding lengths of the bare optical fiber 10 around each non-contact guide 20 in the cooling unit 4.

[0040] The bare optical fiber 10 moves through the internal space S while its direction is changed by multiple non-contact guides 20. After being cooled by the cooling unit 4, the bare optical fiber 10 is sent to the coating unit 5.

[0041] The coating unit 5 is a coating device that applies a coating resin to the outer circumference of the bare optical fiber 10. The coating resin is, for example, an ultraviolet-curing resin. The coating unit 5 may apply two different types of coating resins to the outer circumference of the bare optical fiber 10. For example, the coating unit 5 may apply a primary resin to the bare optical fiber 10, and then apply a secondary resin to the outside of the primary resin. The coating unit 5 may apply the primary resin and the secondary resin to the bare optical fiber 10 almost simultaneously. The bare optical fiber 10 coated with the coating resin is sent to the curing unit 6.

[0042] The curing unit 6 is a curing device that cures the coating resin applied to the bare optical fiber 10 by irradiating it with ultraviolet light. The curing unit 6 has a light-emitting element such as an ultraviolet lamp that emits ultraviolet light. When the coating resin applied to the bare optical fiber 10 hardens, the optical fiber strand 11 is completed. The optical fiber strand 11 is then fed to the roller 7 directly below.

[0043] The lower roller 7 is a roller that changes the direction of travel of the optical fiber strand 11 from a direction along direction X to a predetermined direction. The optical fiber strand 11 whose direction of travel has been changed by the lower roller 7 is sent to the traction roller 8. The traction roller 8 is a roller that pulls and moves the optical fiber strand 11. The movement speed of the bare optical fiber 10 and the optical fiber strand 11 may be adjustable by changing the rotation speed of the traction roller 8. The optical fiber strand 11 is sent from the traction roller 8 to the winding section 9. The winding section 9 is a component that winds the optical fiber strand 11. The winding section 9 may be, for example, a bobbin on which the optical fiber strand 11 can be wound. This completes the manufacturing process of the optical fiber strand 11.

[0044] Referring to Figures 3 and 4, a method for winding the bare optical fiber 10 onto the non-contact guide 20 and a method for adjusting the winding length of the bare optical fiber 10 will be described. Figure 3 shows the state of the bare optical fiber 10 before winding it onto the non-contact guide 20. Figure 4 shows the state of the bare optical fiber 10 after winding it onto the non-contact guide 20. In Figure 4, the bare optical fiber 10 and non-contact guide 20 before winding the bare optical fiber 10 onto the non-contact guide 20 are shown with dashed lines, and the bare optical fiber 10 and non-contact guide 20 after winding are shown with solid lines.

[0045] Before the bare optical fiber 10 is wound around the non-contact guide 20, as shown in Figure 3, the bare optical fiber 10 is positioned to extend along direction X. In direction Y, the bare optical fiber 10 is positioned so as to be sandwiched between odd-numbered non-contact guides 20 and even-numbered non-contact guides 20. The multiple non-contact guides 20 are positioned such that adjacent non-contact guides 20 in the direction of travel of the bare optical fiber 10 are separated by a predetermined distance in direction X. That is, the odd-numbered non-contact guides 20 and even-numbered non-contact guides 20 are arranged alternately so that their positions in direction X do not overlap.

[0046] In this state, the non-contact guides 20 are traversed. The traversal of the non-contact guides 20 is performed using the traversal device 50 (see Figure 1) provided in the manufacturing apparatus 1. The odd-numbered non-contact guides 20 and the even-numbered non-contact guides 20 are traversed in different directions toward the bare optical fiber 10.

[0047] The odd-numbered non-contact guides 20 traverse to a position where their outer edge approximately overlaps with the bare optical fiber 10 extending in direction X (to the position where the bare optical fiber 10 passes through the guide portion 40), as shown in Figure 4. The even-numbered non-contact guides 20 traverse by crossing a virtual line extending downward along direction X from the uppermost non-contact guide 21, which is closest to the optical fiber base material 2. The even-numbered non-contact guides 20 pass between the odd-numbered non-contact guides 20 and traverse to a position to the right of the plane of Figure 4, compared to the position where the bare optical fiber 10 was placed before traversing. By traversing each non-contact guide 20, the bare optical fiber 10 becomes wrapped around the outer circumference of the non-contact guide 20 (the guide portion 40 shown in Figure 2).

[0048] By appropriately adjusting the traverse distance of the non-contact guide 20, the winding length of the bare optical fiber 10 can be increased or decreased, thereby controlling the cooling of the bare optical fiber 10. The control of the cooling of the bare optical fiber 10 (increasing or decreasing the winding length) may be performed in the cooling process of the bare optical fiber 10 during the optical fiber manufacturing process. When increasing or decreasing the winding length, it is not necessary to traverse all of the non-contact guides 20; for example, only the even-numbered non-contact guides 20 may be traversed, or only one of the non-contact guides 20 may be traversed. The relationship between the traverse distance and the winding length will be described later with reference to Figure 7.

[0049] When the traverse of the non-contact guide 20 is complete, the bare optical fiber 10 introduced into the uppermost non-contact guide 21, which is closest to the optical fiber base material 2, and the bare optical fiber 10 discharged from the lowermost non-contact guide 29, which is closest to the coating portion 5, extend along direction X. On the other hand, the bare optical fiber 10 passing between each non-contact guide 20 extends in a direction inclined with respect to direction X. In this embodiment, the length of the bare optical fiber 10 between each non-contact guide 20 is approximately the same. When the traverse of the non-contact guide 20 is complete, a virtual line extending vertically downward from the non-contact guide 21 coincides with a virtual line extending vertically downward from the non-contact guide 29.

[0050] The direction of travel of the bare optical fiber 10 is changed by a predetermined angle α by each non-contact guide 20. The angle α of the direction of travel changed by the non-contact guide 20 is the angle between the direction in which the bare optical fiber 10 travels if the direction of travel is not changed by the non-contact guide 20 and the direction in which the bare optical fiber 10 travels after the direction of travel has been changed by the non-contact guide 20. That is, the angle α changed by the non-contact guide 21 is the angle α1 between the direction in which the bare optical fiber 10 travels if the direction of travel is not changed by the non-contact guide 21 (the direction of travel along the straight line SL1 shown in Figure 4 towards the bottom of the paper) and the direction in which the bare optical fiber 10 travels after the direction of travel has been changed by the non-contact guide 21 (the direction of travel along the straight line SL2 shown in Figure 4 towards the right of the paper). Using the angle θ described later, α1 = π / 2 + θ. Furthermore, the angle α changed by the non-contact guide 22 is the angle α2 formed by the direction in which the bare optical fiber 10 travels (to the right on the page along the straight line SL2 shown in Figure 4) assuming that the direction of travel is not changed by the non-contact guide 22, and the direction in which the bare optical fiber 10 travels after its direction of travel has been changed by the non-contact guide 22 (to the left on the page along the straight line SL3 shown in Figure 4). Using the angle θ described later, α2 = 2θ. Here, the straight line SL3 is a straight line along the bare optical fiber 10 that is discharged from the non-contact guide 22 and introduced into the non-contact guide 23.

[0051] In this embodiment, the direction of travel of the bare optical fiber 10 is changed by an angle α slightly exceeding 90° (for example, an angle between 95° and 110°) by the non-contact guides 21 and 29, and the direction of travel of the bare optical fiber 10 is changed by an angle α (for example, an angle between 10° and 40°) by the other non-contact guides 22 to 28.

[0052] Figure 5 shows two adjacent non-contact guides 20 in direction X. In Figure 5, non-contact guides 21 and 22 are shown as examples. For explanatory purposes, in Figure 5, the width in direction Y between non-contact guides 21 and 22 is shown to be smaller than in Figure 4. In Figure 5, non-contact guides 21 and 22 in the state where traversing has been completed are shown with solid lines. Also in Figure 5, when non-contact guide 22 begins traversing and the bare optical fiber 10 extends downward along direction X, the non-contact guide 22 located at the point where the bare optical fiber 10 passes through the guide section 40 without bending (hereinafter referred to as the reference point) is designated as non-contact guide 22A and is shown with a dashed line.

[0053] Here, we will explain the distances between each point shown in Figure 5. The pitch width H shown in Figure 5 is the distance in direction X between the central axes C of adjacent non-contact guides 20. The pitch width H may be adjustable by changing the position of each non-contact guide 20 in direction X. The horizontal distance L is the distance in direction Y between the central axes C of adjacent non-contact guides 20. The horizontal distance L may be, for example, 50 mm or more and 450 mm or less. The horizontal distance L may be adjustable by changing the position of each non-contact guide 20 in direction Y (by traversing each non-contact guide 20).

[0054] The winding diameter D1 is the diameter of the circle formed by the bare optical fiber 10 when it is wound around the entire circumference of the guide portion 40 of each non-contact guide 20. The winding diameter D1 may be, for example, 50 mm or more and 200 mm or less. The outer diameter D2 is the diameter of the flange portion of each non-contact guide 20 (the diameter of the outer edge of the non-contact guide 20 when viewed from direction Z). The outer diameter D2 may be, for example, 80 mm or more and 230 mm or less. Multiple non-contact guides 20 are arranged at regular intervals such that the pitch width H between the multiple non-contact guides 20 is greater than the outer diameter D2 of each of the multiple non-contact guides 20. The pitch width H may be, for example, 150 mm or more and 200 mm or less. The traverse distance L11 is the distance in direction Y between the central axis C of the non-contact guide 20 located at the reference point (non-contact guide 22A shown in Figure 5) and the central axis C of the non-contact guide 20 after traversing (for example, the non-contact guide 22 shown in Figure 5). The traverse distance L11 only needs to be greater than 0 mm, and may be, for example, 100 mm or more and 500 mm or less, 200 mm or more and 400 mm or less, or approximately 350 mm.

[0055] The bare optical fiber 10, after being inserted into the internal space S, moves along direction X and is then passed through the guide portion 40 of the non-contact guide 21. The bare optical fiber 10 then moves along the guide portion 40, wrapping around the non-contact guide 21, and is discharged from the guide portion 40 to the non-contact guide 22. The bare optical fiber 10 between the non-contact guide 21 and the non-contact guide 22 extends in a direction intersecting direction X at an angle θ. The bare optical fiber 10 sent to the non-contact guide 22 is then passed through the guide portion 40 of the non-contact guide 22. The bare optical fiber 10 then moves along the guide portion 40, wrapping around the non-contact guide 22, and is discharged from the guide portion 40 to the non-contact guide 23 (see Figure 4). At this time, the horizontal distance L is calculated using the following formula (1). L = (H - D1 / cosθ) / tanθ …(1)

[0056] Next, we will explain the winding length and air length of the bare optical fiber 10. As mentioned above, the winding length of the bare optical fiber 10 is the length of the portion of the bare optical fiber 10 that is passed through the guide portion 40 and is located on an arc centered on the central axis C of the non-contact guide 20 (hereinafter referred to as the winding portion). The winding length L21 of the bare optical fiber 10 with respect to the non-contact guide 21 can be calculated using the following formula (2). L21 = D1(π-2θ) / 4 …(2) Furthermore, the length of the wrap-around length of the bare optical fiber 10 around the non-contact guide 29 (see Figure 4) can also be calculated using the same formula as in formula (2).

[0057] The length L22 of the wrap-around length L22 of the bare optical fiber 10 around the non-contact guide 22 can be determined by the following formula (3). L22 = D1(π-2θ) / 2 …(3) Furthermore, the length of the wrap-around length of the bare optical fiber 10 around the non-contact guides 23 to 28 (see Figure 4) can also be calculated using the same formula as in formula (3).

[0058] The air length of the bare optical fiber 10 is the length of the portion of the bare optical fiber 10 that connects the wound portions. The air length L31 of the bare optical fiber 10 between the non-contact guides 21 and 22 can be calculated using the following formula (4). L31 = D1tanθ + L / cosθ …(4) Furthermore, the air length of the bare optical fiber 10 between other non-contact guides 20 can also be calculated using the same formula as formula (4).

[0059] Figure 6 is a graph showing the calculated relationship between cooling distance and fiber temperature. In Figure 6, the horizontal axis represents the cooling distance (unit: mm), and the vertical axis represents the fiber temperature (unit: °C). Here, the cooling distance is the distance the bare optical fiber 10 travels in the internal space S of the cooling unit 4 (see Figure 1). The cooling distance is calculated using the formulas described above as appropriate. Fiber temperature is the temperature of the bare optical fiber 10. Each line in Figure 6 shows the fiber temperature when the bare optical fiber 10 was cooled under different conditions A1 to A3. In the measurements for conditions A1 and A2, the bare optical fiber 10 was moved linearly along direction X in the internal space S without using the non-contact guide 20. In addition, in the measurement for condition A1, the linear velocity of the bare optical fiber 10 was set to the conventional condition Y1 m / min, and in the measurement for condition A2, the linear velocity of the bare optical fiber 10 was set to 1.2 × Y1 m / min.

[0060] On the other hand, in the measurement under condition A3, the bare optical fiber 10 was moved while changing its direction of travel using a non-contact guide 20. In the measurement under condition A3, eight non-contact guides 20 were used, the horizontal distance L between each non-contact guide 20 (see Figure 5) was set to 500 mm, and the linear velocity of the bare optical fiber 10 was set to 1.2 × Y 1 m / min. In addition, in all conditions from condition A1 to condition A3, it was assumed that the temperature of the bare optical fiber 10 when it was entered into the internal space S was approximately 600°C.

[0061] As shown in Figure 6, in measurements under condition A3, the fiber temperature decreased to approximately 100°C with a shorter cooling distance compared to measurements under conditions A1 and A2. By cooling the bare optical fiber 10 to approximately 100°C, a resin coating can be appropriately applied to the outer circumference of the bare optical fiber 10.

[0062] Furthermore, in measurements under conditions A1 and A2, the fiber temperature decreases gradually. On the other hand, in measurements under condition A3, portions where the fiber temperature decreases gradually and portions where it decreases rapidly alternate. Of these, the portions where the fiber temperature decreases rapidly correspond to the portion of the bare optical fiber 10 that is wrapped around the non-contact guide 20. According to the inventors' findings, it is thought that the fiber temperature decreases rapidly due to the gas blown from the guide portion 40 when the bare optical fiber 10 is wrapped around the non-contact guide 20. In other words, by increasing or decreasing the length of the wrapping around the non-contact guide 20 compared to the length of air between the non-contact guides 20, it is possible to adjust the cooling efficiency of the bare optical fiber 10 more significantly.

[0063] Figure 7 is a graph showing the relationship between the traverse distance L11 and the total winding length L20. In Figure 7, the horizontal axis represents the traverse distance L11 (unit: mm) of the even-numbered non-contact guides 20, and the vertical axis represents the total winding length L20 (unit: mm) of the bare optical fiber 10. The graph in Figure 7 shows the change in the total winding length L20 when the traverse distance L11 of the even-numbered non-contact guides 20 is changed under each of the conditions B1 to B3. The pitch width H between each non-contact guide 20 was 150 mm under condition B1, 170 mm under condition B2, and 190 mm under condition B3. Also, for all conditions, this is an example where the number of non-contact guides 20 in the cooling unit 4 is 9, and the winding diameter D1 of each non-contact guide 20 is 120 mm.

[0064] As shown in Figure 7, in all three conditions from B1 to B3, the total winding length L20 increases as the traverse distance L11 of the even-numbered non-contact guides 20 increases. However, the increase in the total winding length L20 relative to the increase in the traverse distance L11 gradually decreases as the traverse distance L11 increases. It can be seen that when the traverse distance L11 exceeds approximately 300 mm, the total winding length L20 remains almost constant even when the traverse distance L11 is increased. A similar trend is observed when the total winding length L20 is calculated with the number of non-contact guides 20 in the cooling unit 4 set to 5 and 7.

[0065] Figure 8 is a graph showing the relationship between the traverse distance L11 and the total air length L30. In Figure 8, the horizontal axis represents the traverse distance L11 (unit: mm) of the even-numbered non-contact guides 20, and the vertical axis represents the total air length L30 (unit: mm). Here, the total air length is the sum of the air lengths between each non-contact guide 20. The graph in Figure 8 shows the change in the total air length L30 when the traverse distance L11 of the even-numbered non-contact guides 20 is changed under each of the conditions C1 to C3. The number of non-contact guides 20 in the cooling unit 4 was 5 under condition C1, 7 under condition C2, and 9 under condition C3. Also, for all conditions, the pitch width H was 170 mm, and the winding diameter D1 of each non-contact guide 20 was 120 mm.

[0066] As shown in Figure 8, in all three conditions C1 to C3, the total aerial length L30 increases as the traverse distance L11 of the even-numbered non-contact guides 20 increases. In contrast to Figure 7, unlike the total winding length L20 mentioned above, the increase in the total aerial length L30 does not decrease even when the traverse distance L11 exceeds 300 mm. The total aerial length L30 shows a similar trend when the pitch width H of the non-contact guides 20 is set to 150 mm and 190 mm.

[0067] Figure 9 is a graph showing the relationship between the traverse distance L11 and the total winding length L20. In Figure 9, the horizontal axis represents the traverse distance L11 (unit: mm) of the even-numbered non-contact guides 20, and the vertical axis represents the total winding length L20 (unit: mm). The graph in Figure 9 shows the change in the total winding length L20 when the traverse distance L11 of the even-numbered non-contact guides 20 is changed under each of the conditions E1 to E3.

[0068] Under condition E1, the cooling unit 4 had 9 non-contact guides 20, a winding diameter D1 of 100 mm, and a pitch width H of 150 mm. Under condition E2, the cooling unit 4 had 9 non-contact guides 20, a winding diameter D1 of 120 mm, and a pitch width H of 170 mm. Under condition E3, the cooling unit 4 had 7 non-contact guides 20, a winding diameter D1 of 150 mm, and a pitch width H of 190 mm. Furthermore, the total height T (see Figure 4) from the upper end of the non-contact guide 20 located at the top of the cooling unit 4 to the lower end of the non-contact guide 20 located at the bottom was 1300 mm under condition E1, 1480 mm under condition E2, and 1350 mm under condition E3.

[0069] As shown in Figure 9, the total winding length L20 under condition E3, where there are 7 non-contact guides 20, is greater than the total winding length L20 under condition E1, where there are 9 non-contact guides 20. In other words, even when the number of non-contact guides 20 is reduced, the total winding length L20 can be increased by adjusting the winding diameter D1 and pitch width H. Furthermore, even if the total height T (and therefore the height of the cooling equipment) is similar or the same under conditions E1 and E3, the total winding length L20 can be increased under condition E3 compared to condition E1.

[0070] Furthermore, the total winding length L20 under condition E2, where the winding diameter D1 is 120 mm, is greater than the total winding length L20 under condition E3, where the winding diameter D1 is 150 mm. In other words, even when the winding diameter D1 is reduced, the total winding length L20 can be increased by adjusting the number of non-contact guides 20 and the pitch width H.

[0071] As described above, the winding length of the bare optical fiber 10 can be increased or decreased by appropriately changing the number of non-contact guides 20, the winding diameter D1, the pitch width H, and the traverse distance L11. The operation of increasing or decreasing the winding length may be performed in the cooling process of the bare optical fiber 10 during the optical fiber manufacturing process. Furthermore, the total winding length L20 of the bare optical fiber 10 may be maximized by considering the space available for the manufacturing apparatus 1, the weight of each non-contact guide 20, etc.

[0072] As described above, according to the optical fiber manufacturing method of this embodiment, the winding length of the bare optical fiber 10 can be increased or decreased by adjusting the positions of the multiple non-contact guides 20. Increasing or decreasing the winding length of the bare optical fiber 10 has a greater effect on cooling efficiency than increasing or decreasing the air length of the bare optical fiber 10 between each non-contact guide 20. Therefore, according to the above manufacturing method, the cooling efficiency of the bare optical fiber 10 can be adjusted over a wider range, and the cooling of the bare optical fiber 10 can be appropriately controlled.

[0073] In the optical fiber manufacturing method according to this embodiment, at least one of the multiple non-contact guides 20 is a movable non-contact guide capable of traversing along the horizontal direction (direction Y). The cooling of the bare optical fiber 10 is controlled by adjusting the traverse distance of the movable non-contact guide to increase or decrease the winding length. In this case, the movable non-contact guide moves along the horizontal direction (direction Y). Therefore, compared to the case where the movable non-contact guide moves in an irregular direction, it is easier to calculate the winding length of the bare optical fiber 10 and to control the cooling of the bare optical fiber 10.

[0074] In the optical fiber manufacturing method according to this embodiment, the plurality of non-contact guides 20 are an odd number of non-contact guides 20, three or more. The movable non-contact guides located in even positions from the optical fiber base material 2 are traversed horizontally to increase or decrease the winding length. In this case, the entry position of the bare optical fiber 10 to the non-contact guide 21 closest to the device for melting the optical fiber base material 2 (wire drawing furnace 3) and the exit position of the bare optical fiber 10 to the non-contact guide 29 closest to the device for coating the bare optical fiber 10 (coating section 5) can be aligned on the same side. This makes it easy to manage the winding length.

[0075] In the optical fiber manufacturing method according to this embodiment, the traverse distance of the moving non-contact guide may be greater than 0 mm and 350 mm or less. In this case, by having a traverse distance of 350 mm or less, it is possible to suppress an increase in the manufacturing space for the optical fiber. Also, when the traverse distance is 350 mm or less, the amount of variation in the total winding length L20 of the bare optical fiber 10 is large with respect to the amount of variation in the traverse distance L11. Therefore, by slightly increasing or decreasing the traverse distance L11, the cooling efficiency of the bare optical fiber 10 can be greatly adjusted, and the cooling of the bare optical fiber 10 can be appropriately controlled.

[0076] In the optical fiber manufacturing method according to this embodiment, when the traverse of the moving non-contact guide is completed, a virtual line extending vertically downward from the non-contact guide 21 closest to the optical fiber base material 2 among the multiple non-contact guides 20 coincides with a virtual line extending vertically downward from the non-contact guide 29 closest to the coating portion 5 among the multiple non-contact guides 20. In this case, it becomes easier to manage the length of the wrapping of the bare optical fiber 10 around the non-contact guide 20, and the cooling of the bare optical fiber 10 can be controlled more appropriately.

[0077] In the optical fiber manufacturing method according to this embodiment, the moving non-contact guide is positioned to traverse a virtual line extending downward in the vertical direction (direction X) from the non-contact guide 20 closest to the optical fiber base material 2 among a plurality of non-contact guides 20, crossing it. In this case, the range of increase or decrease in the length wrapped around the non-contact guide 20 can be made larger, and the cooling of the bare optical fiber 10 can be appropriately controlled. In addition, the size of the optical fiber manufacturing apparatus 1 can be suppressed.

[0078] In the optical fiber manufacturing method according to this embodiment, among the plurality of non-contact guides 20, adjacent non-contact guides 20 in the direction of travel of the bare optical fiber 10 are spaced apart in the vertical direction (direction X). The plurality of non-contact guides 20 are arranged at regular intervals such that the pitch width H between the plurality of non-contact guides 20 is greater than the outer diameter D2 of each of the plurality of non-contact guides 20. In this case, when the non-contact guides 20 are traversed in the horizontal direction (direction Y), the length of the bare optical fiber 10 wrapped around the non-contact guides 20 can be increased or decreased. Therefore, the cooling of the bare optical fiber 10 can be appropriately controlled.

[0079] In the optical fiber manufacturing method according to this embodiment, the cooling of the bare optical fiber 10 is controlled by increasing or decreasing the winding length, and the winding length may be adjusted during the process of cooling the bare optical fiber 10. When cooling control is performed while the cooling process of the bare optical fiber 10 is being carried out, the cooling control of the bare optical fiber 10 can be performed at a more appropriate timing, and a more highly accurate optical fiber strand 11 can be obtained.

[0080] In the optical fiber manufacturing apparatus 1 according to this embodiment, the winding length of the bare optical fiber 10 can be increased or decreased by adjusting the positions of the multiple non-contact guides 20. Increasing or decreasing the winding length of the bare optical fiber 10 has a greater effect on cooling efficiency than increasing or decreasing the air length of the bare optical fiber 10 between each non-contact guide 20. Therefore, by using the above manufacturing apparatus 1, the cooling efficiency of the bare optical fiber 10 can be adjusted more significantly, and the cooling of the bare optical fiber 10 can be appropriately controlled.

[0081] The optical fiber manufacturing apparatus 1 according to this embodiment includes a device (traverse device 50) that traverses a movable non-contact guide. The movable non-contact guide is capable of traversing along the horizontal direction (direction Y). Multiple non-contact guides 20 are arranged to control the cooling of the bare optical fiber 10 by adjusting the traverse distance of the movable non-contact guide to increase or decrease the winding length. In this case, the movable non-contact guide moves along the horizontal direction (direction Y). Therefore, compared to the case where the movable non-contact guide moves in an irregular direction, it is possible to easily calculate the winding length of the bare optical fiber 10 and control the cooling of the bare optical fiber 10.

[0082] In the optical fiber manufacturing apparatus 1 according to this embodiment, the movable non-contact guide may be arranged to traverse a virtual line that crosses a line extending vertically downward from the non-contact guide 21, which is the closest to the optical fiber base material 2 among the multiple non-contact guides 20. In this case, the range of increase or decrease in the length around the non-contact guide 20 can be increased, and the cooling of the bare optical fiber 10 can be appropriately controlled. In addition, the size of the optical fiber manufacturing apparatus 1 can be suppressed.

[0083] In the optical fiber manufacturing apparatus 1 according to this embodiment, among the plurality of non-contact guides 20, adjacent non-contact guides 20 in the direction of travel of the bare optical fiber 10 are spaced apart in the vertical direction (direction X). The plurality of non-contact guides 20 are arranged at regular intervals such that the pitch width H between the plurality of non-contact guides 20 is greater than the outer diameter D2 of each of the plurality of non-contact guides 20. In this case, when the non-contact guides 20 are traversed in the horizontal direction (direction Y), the length of the bare optical fiber 10 wrapped around the non-contact guides 20 can be increased or decreased. Therefore, the cooling of the bare optical fiber 10 can be appropriately controlled.

[0084] In the optical fiber manufacturing apparatus 1 according to this embodiment, the cooling mechanism (cooling section 4) may have 3 to 15 non-contact guides 20. In this case, by having 3 or more non-contact guides 20, the total winding length L20 of the bare optical fiber 10 can be adjusted. Furthermore, by having 15 or fewer non-contact guides 20, the size of the optical fiber manufacturing apparatus 1 can be suppressed.

[0085] In the optical fiber manufacturing apparatus 1 according to this embodiment, the winding diameter D1 of each non-contact guide 20 may be 50 mm or more and 200 mm or less. In this case, by having a winding diameter D1 of each non-contact guide 20 of 50 mm or more, a sufficient winding length of the bare optical fiber 10 around each non-contact guide 20 can be secured, and the cooling of the bare optical fiber 10 can be appropriately controlled. Furthermore, by having a winding diameter D1 of each non-contact guide 20 of 200 mm or less, the size of the optical fiber manufacturing apparatus 1 can be suppressed.

[0086] <First variation> Referring to Figure 10, a first modified example of the optical fiber manufacturing apparatus 1 and manufacturing method will be described. Figure 10 shows the state in which the bare optical fiber 10 is wound around the non-contact guide 20 in the internal space S of the optical fiber manufacturing apparatus according to the first modified example. In the following description, the differences from the above-described embodiment will be mainly explained, and common points may be omitted from the explanation. In Figure 10, the bare optical fiber 10 and non-contact guide 20 before the bare optical fiber 10 is wound around the non-contact guide 20 are shown with dashed lines, and the bare optical fiber 10 and non-contact guide 20 after winding are shown with solid lines.

[0087] In the embodiment described above, as shown in Figure 4, the even-numbered non-contact guides 20 traverse a greater distance than the odd-numbered non-contact guides 20 in the cooling section 4. On the other hand, this modified example differs from the above embodiment in that in the cooling section 4A, a portion of the odd-numbered non-contact guides 20 traverse a distance approximately the same as that of the even-numbered non-contact guides 20.

[0088] Before the bare optical fiber 10 is wound around the non-contact guide 20, it is arranged to extend along direction X, similar to the embodiment described above. The bare optical fiber 10 is positioned so as to be sandwiched between odd-numbered non-contact guides 20 and even-numbered non-contact guides 20 in direction Y. The multiple non-contact guides 20 are arranged such that adjacent non-contact guides 20 in the direction of travel of the bare optical fiber 10 are spaced apart in direction X. That is, the odd-numbered non-contact guides 20 and even-numbered non-contact guides 20 are arranged alternately so that their positions in direction X do not overlap.

[0089] In this state, the odd-numbered non-contact guides 20 and the even-numbered non-contact guides 20 traverse toward the bare optical fiber 10 in different directions. Specifically, the odd-numbered non-contact guides 20 traverse in the direction of arrow A shown in Figure 10, and the even-numbered non-contact guides 20 traverse in the direction of arrow B shown in Figure 10.

[0090] Of the odd-numbered non-contact guides 20, the uppermost non-contact guide 21 (first non-contact guide) closest to the optical fiber base material 2, and the lowermost non-contact guide 29 (second non-contact guide) closest to the coating portion 5, traverse to a position where their outer edges approximately overlap with the bare optical fiber 10 extending in direction X (to the position where the bare optical fiber 10 is passed through the guide portion 40). The odd-numbered non-contact guides 20 (non-contact guides 23, 25, and 27), excluding non-contact guides 21 and 29, traverse to approximately the same distance as the even-numbered non-contact guides 20. By appropriately adjusting the traverse distance of each non-contact guide 20, the length around which the bare optical fiber 10 is wrapped can be increased or decreased, thereby controlling the cooling of the bare optical fiber 10.

[0091] In the optical fiber manufacturing method according to this modified example, the multiple non-contact guides 20 are four or more non-contact guides 20. Of the multiple non-contact guides 20, the non-contact guides 20 (non-contact guides 21 to 28) excluding the non-contact guide 21 closest to the optical fiber base material 2 and the non-contact guide 29 closest to the resin coating device (coating section 5) are movable non-contact guides. The non-contact guides 23, 25, and 27 located in odd-numbered positions from the optical fiber base material 2 and the non-contact guides 22, 24, 26, and 28 located in even-numbered positions from the optical fiber base material 2 are traversed in different directions in the horizontal direction (direction Y) but over approximately the same distance to increase or decrease the winding length. In this case, the lengths of the bare optical fiber 10 between the non-contact guides 20 excluding the non-contact guides 21 and 29 become approximately the same, making it easy to calculate the total winding length L20 of the bare optical fiber 10. Therefore, it is easy to appropriately control the cooling of the bare optical fiber 10.

[0092] <Second variation> Referring to Figure 11, a second modified example of the optical fiber manufacturing apparatus 1 and manufacturing method will be described. Figure 11 shows the state in which the bare optical fiber 10 is wound around the non-contact guide 20 in the internal space S of the optical fiber manufacturing apparatus according to the second modified example. In the following description, the differences from the above-described embodiment will be mainly explained, and common points may be omitted from the explanation. In Figure 11, the bare optical fiber 10 and non-contact guide 20 before the bare optical fiber 10 is wound around the non-contact guide 20 are shown with dashed lines, and the bare optical fiber 10 and non-contact guide 20 after winding are shown with solid lines.

[0093] As shown in Figure 4, the cooling unit 4 according to the above embodiment has an odd number (9) non-contact guides 20. On the other hand, the cooling unit 4B according to this modified example differs from the above embodiment in that it has an even number (8) non-contact guides 20, as shown in Figure 11.

[0094] Before the bare optical fiber 10 is wound around the non-contact guide 20, it is arranged to extend along direction X, similar to the embodiment described above. The bare optical fiber 10 is positioned so as to be sandwiched between odd-numbered non-contact guides 20 and even-numbered non-contact guides 20 in direction Y. The multiple non-contact guides 20 are arranged such that adjacent non-contact guides 20 in the direction of travel of the bare optical fiber 10 are spaced apart in direction X. That is, the odd-numbered non-contact guides 20 and even-numbered non-contact guides 20 are arranged alternately so that their positions in direction X do not overlap.

[0095] In this state, the odd-numbered non-contact guides 20 and the even-numbered non-contact guides 20 traverse toward the bare optical fiber 10 in different directions. Specifically, the odd-numbered non-contact guides 20 traverse in the direction of arrow A shown in Figure 11, and the even-numbered non-contact guides 20 traverse in the direction of arrow B shown in Figure 11.

[0096] Of the odd-numbered non-contact guides 20, the uppermost non-contact guide 21, which is closest to the optical fiber base material 2, and the lowermost non-contact guide 28, which is closest to the coating portion 5, traverse to a position where their outer edges approximately overlap with the bare optical fiber 10 extending in direction X (to the position where the bare optical fiber 10 is passed through the guide portion 40). The odd-numbered non-contact guides 20 (non-contact guides 23, 25, and 27), excluding non-contact guide 21, traverse to approximately the same distance as the even-numbered non-contact guides 20 (non-contact guides 22, 24, and 26), excluding non-contact guide 28. By appropriately adjusting the traverse distance of each non-contact guide 20, the length around which the bare optical fiber 10 is wrapped can be increased or decreased, thereby controlling the cooling of the bare optical fiber 10.

[0097] In the optical fiber manufacturing method according to this modified example, the number of non-contact guides 20 is four or more non-contact guides 20. Of the number of non-contact guides 20, the non-contact guides 20 (non-contact guides 21 to 27) excluding the non-contact guide 21 closest to the optical fiber base material 2 and the non-contact guide 28 closest to the resin coating device (coating section 5) are movable non-contact guides. The non-contact guides 20 located in odd-numbered positions from the optical fiber base material 2 (non-contact guides 23, 25, and 27) and the non-contact guides 20 located in even-numbered positions from the optical fiber base material 2 (non-contact guides 22, 24, and 26) are traversed in different directions in the horizontal direction (direction Y) but over approximately the same distance to increase or decrease the winding length. In this case, the lengths of the bare optical fiber 10 between the non-contact guides 20 excluding non-contact guides 21 and 28 become approximately the same, making it easy to calculate the total winding length L20 of the bare optical fiber 10. Therefore, it is easy to appropriately control the cooling of the bare optical fiber 10.

[0098] Although embodiments relating to this disclosure have been described in detail above, the present invention is not limited to the above embodiments and can be applied to various embodiments.

[0099] The traverse distance of each non-contact guide 20 may be different. Also, the winding diameter D1 and outer diameter D2 of each non-contact guide 20 may be different. Each non-contact guide 20 may be movable not only in direction Y, but also along directions X and Z, or along directions intersecting these directions. [Explanation of Symbols]

[0100] 1...Manufacturing equipment 2… Optical fiber base material 3…Line drawing furnace 4, 4A, 4B...Cooling section 5…Coating part 6…Hardened part 7... Directly below roller 8... Towing roller 9... Winding section 10… Bare fiber optic cable 11… Optical fiber strand 20, 21, 22, 22A, 23, 24, 25, 26, 27, 28, 29... Contactless guide 30…First flange 35…Second flange 40… Guide section 50... Traverse device C…Central axis D1...Wrap diameter D2…Outer diameter H...Pitch width L…Horizontal distance L11...Traverse distance L20...Long with full wrap L21, L22... Wrapping length L30...Total air length L31…Aerial length S…interior space θ…Angle

Claims

1. The process involves melting the optical fiber preform and drawing bare optical fiber wires, A step of changing the direction of the bare optical fiber using a plurality of non-contact guides while cooling the bare optical fiber using the plurality of non-contact guides, The process of coating the aforementioned bare optical fiber with resin, Equipped with, Each of the non-contact guides has a guide portion along its outer surface on which a part of the bare optical fiber can be wound, and the guide portion is provided with an outlet for blowing out gas to suspend the bare optical fiber. By adjusting the position of at least one of the plurality of non-contact guides, the cooling of the bare optical fiber is controlled by increasing or decreasing the winding length, which is the length of the portion of the bare optical fiber that comes into direct contact with the gas from the plurality of non-contact guides. Among the plurality of non-contact guides, adjacent non-contact guides in the direction of travel of the bare optical fiber are separated vertically. The plurality of non-contact guides are arranged at regular intervals such that the pitch width H between the plurality of non-contact guides is greater than the outer diameter D2 of each of the plurality of non-contact guides. A method for manufacturing optical fibers.

2. Of the plurality of non-contact guides, at least one non-contact guide is a movable non-contact guide capable of traversing along the horizontal direction. The cooling of the bare optical fiber is controlled by adjusting the traverse distance of the moving non-contact guide to increase or decrease the winding length. A method for manufacturing an optical fiber according to claim 1.

3. The aforementioned plurality of non-contact guides are three or more odd-numbered non-contact guides, The moving non-contact guide located at an even number of positions from the optical fiber base material among the plurality of non-contact guides is traversed horizontally to increase or decrease the winding length. The method for manufacturing an optical fiber according to claim 2.

4. The aforementioned multiple non-contact guides consist of four or more non-contact guides. The non-contact guides, excluding the first non-contact guide closest to the optical fiber base material and the second non-contact guide closest to the resin coating device, are the movable non-contact guides. The moving non-contact guides located at odd-numbered positions from the optical fiber base material and the moving non-contact guides located at even-numbered positions from the optical fiber base material are traversed in different directions horizontally over substantially the same distance to increase or decrease the winding length. The method for manufacturing an optical fiber according to claim 2.

5. The traverse distance of the aforementioned moving non-contact guide is greater than 0 mm and 350 mm or less. A method for manufacturing an optical fiber according to any one of claims 2 to 4.

6. When the traverse of the moving non-contact guide is completed, a virtual line extending vertically downward from the non-contact guide closest to the optical fiber base material among the plurality of non-contact guides coincides with a virtual line extending vertically downward from the non-contact guide closest to the resin coating device among the plurality of non-contact guides. A method for manufacturing an optical fiber according to any one of claims 2 to 5.

7. The movable non-contact guide is positioned to traverse a virtual line extending vertically downward from the non-contact guide closest to the optical fiber base material among the plurality of non-contact guides, crossing the virtual line. A method for manufacturing an optical fiber according to any one of claims 2 to 6.

8. The cooling of the bare optical fiber is controlled by increasing or decreasing the winding length, and the increase or decrease in the winding length is performed in the process of cooling the bare optical fiber. A method for manufacturing an optical fiber according to any one of claims 1 to 7.

9. A melting apparatus for melting the optical fiber preform in order to draw bare optical fiber wires from the optical fiber preform, A cooling mechanism for cooling the aforementioned bare optical fiber, A coating device for coating the aforementioned bare optical fiber with resin, Equipped with, The cooling mechanism has a plurality of non-contact guides that change the direction of travel of the bare optical fiber, Each of the non-contact guides has a guide portion along its outer surface on which a part of the bare optical fiber can be wound, and the guide portion is provided with an outlet for blowing out gas to suspend the bare optical fiber. At least one of the plurality of non-contact guides is a movable non-contact guide that can move to increase or decrease the winding length, which is the length of the portion of the bare optical fiber that comes into direct contact with the gas from the plurality of non-contact guides relative to the guide portion. Among the plurality of non-contact guides, adjacent non-contact guides in the direction of travel of the bare optical fiber are separated vertically. The plurality of non-contact guides are arranged at regular intervals such that the pitch width H between the plurality of non-contact guides is greater than the outer diameter D2 of each of the plurality of non-contact guides. Optical fiber manufacturing equipment.

10. The device further comprises a device for traversing the aforementioned movable non-contact guide, The aforementioned mobile non-contact guide is capable of traversing along the horizontal direction. The plurality of non-contact guides are arranged to control the cooling of the bare optical fiber by adjusting the traverse distance of the moving non-contact guides to increase or decrease the winding length. The apparatus for manufacturing optical fibers according to claim 9.

11. The movable non-contact guide is positioned to traverse a virtual line extending vertically downward from the non-contact guide closest to the optical fiber base material among the plurality of non-contact guides, crossing the virtual line. The optical fiber manufacturing apparatus according to claim 10.

12. The cooling mechanism has three to fifteen of the non-contact guides. An apparatus for manufacturing optical fibers according to any one of claims 9 to 11.

13. The winding diameter of each of the aforementioned non-contact guides is 50 mm or more and 200 mm or less. An apparatus for manufacturing optical fibers according to any one of claims 9 to 12.

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